CA2268471C - Sheet-pressing member for sheet feeding mechanism - Google Patents
Sheet-pressing member for sheet feeding mechanism Download PDFInfo
- Publication number
- CA2268471C CA2268471C CA002268471A CA2268471A CA2268471C CA 2268471 C CA2268471 C CA 2268471C CA 002268471 A CA002268471 A CA 002268471A CA 2268471 A CA2268471 A CA 2268471A CA 2268471 C CA2268471 C CA 2268471C
- Authority
- CA
- Canada
- Prior art keywords
- sheet
- pressing
- printhead
- central axis
- shaft portion
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
- B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
- B41J13/00—Devices or arrangements of selective printing mechanisms, e.g. ink-jet printers or thermal printers, specially adapted for supporting or handling copy material in short lengths, e.g. sheets
- B41J13/02—Rollers
- B41J13/076—Construction of rollers; Bearings therefor
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
- B65H5/00—Feeding articles separated from piles; Feeding articles to machines
- B65H5/06—Feeding articles separated from piles; Feeding articles to machines by rollers or balls, e.g. between rollers
- B65H5/062—Feeding articles separated from piles; Feeding articles to machines by rollers or balls, e.g. between rollers between rollers or balls
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
- B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
- B41J13/00—Devices or arrangements of selective printing mechanisms, e.g. ink-jet printers or thermal printers, specially adapted for supporting or handling copy material in short lengths, e.g. sheets
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
- B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
- B41J13/00—Devices or arrangements of selective printing mechanisms, e.g. ink-jet printers or thermal printers, specially adapted for supporting or handling copy material in short lengths, e.g. sheets
- B41J13/02—Rollers
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
- B65H2402/00—Constructional details of the handling apparatus
- B65H2402/50—Machine elements
- B65H2402/54—Springs, e.g. helical or leaf springs
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
- B65H2404/00—Parts for transporting or guiding the handled material
- B65H2404/10—Rollers
- B65H2404/11—Details of cross-section or profile
- B65H2404/112—Means for varying cross-section
- B65H2404/1122—Means for varying cross-section for rendering elastically deformable
- B65H2404/11221—Means for varying cross-section for rendering elastically deformable involving spring
Abstract
A sheet feeding mechanism includes a sheet feed roller for transporting a sheet along a paper transport path, and a sheet- pressing member disposed so as to press the sheet feed roller. The sheet-pressing member integrally includes a pressing portion which is formed by increasing the diameter of a part of a coiled portion of a compression coil spring.
Description
SHEET-PRESSING MEMBER FOR SHEET FEEDING MECHANISM
BACKGROUND OF THE INVENTION
The present invention relates to a sheet feeding mechanism in use with an ink jet printer, for example, and more particularly to a sheet feeding mechanism including an object pressing member for pressing a printed sheet.
To print by an ink jet printer, the nozzle orifices of a printhead selectively eject ink drops onto a printing paper in accordance with print information while synchronizing with a relative movement of a printhead relative to a printing paper.
Generally, to feed a printing paper in the printer, the printing paper is nipped by a pair of paper-feed rollers, and one of the paired rollers is rotated.
In the case of the ink jet pririter, characters, for example, printed on the printing paper are not fixed. Accordingly, when the printed paper is pressed against the rollers, ink of the printed characters is still wet. The wet ink sticks onto the roller, and is transferred from the roller to the sheet or paper.
An ink jet printer designeci to solve the ink sticking problem is disclosed in JP-A-2-41277.
In the ink jet printer, the sheet is held by pressing the medium on the sheet feed roller. Therefore, the ink jet printer indispensably includes a sheet-pressing member having a, spur gear with sharp teeth on the shaft.
The sheet-pressing member iz;designed to act elastically to the spur gear or the shaft, and the thus designed member presses the printing paper against the sheet feed roller.
A contact area where the spur gear is in contact with the paper is small in the ink jet printer using the thus constructed sheet-pressing member. Therefore, rio ink transfer to the paper takes place in such a printer.
The sheet-pressing member of the printer takes the form of a bar or a plate, and the thus shaped member, while being bent, presses the sheet against the sheet feed roller.
The sheet-pressing member has a large spring constant, and inevitably suffers from dimensional variations. For this reason, work to properly set a pressing force is very difficult.
Where the pressing force is too large, an excessive load acts on the paper being fed. On the other hand, where it is too small, a sheet feeding force is insufficient. Either case leads to degradation of print quality.
SUMMARY OF THE INVENTION
Accordingly, an object of the present invention is to provide an ink jet printer with a sheet feeding mechanism which imparts an optimum pressing force onto a sheet being transported.
To achieve the above object, there is provided an object pressing member for pressing a sheet being transported along a transport path, the object-pressing member including a pressing portion of large diameter being shaped like an eddy current by spirally coiling an elastic wire.
A sheet feeding mechanism includes a sheet feed roller and a sheet-pressing member disposed so as to press the sheet feed roller, the sheet-pressing member including a pressing portion of large diameter being shaped like an eddy current by spirally coiling an elastic wire.
A printer for printing on a sheet set therein, the printer having a printhead, and a sheet feeding mechanism disposed downward of the printhead when viewed in a sheet feeding direction, wherein the sheet feeding mechanism comprises a sheet feed roller for feeding a sheet printed by the printhead in a predetermined direction; and a sheet-pressing member disposed so as to press the sheet feed roller, the sheet-pressing member including a pressing portion of large diameter being shaped like an eddy current by spirally coiling an elastic wire.
The sheet-pressing member includes a coil spring portion formed by spirally coiling the wire so that the wire rings formed are brought into close contact with one another, and the pressing portion is formed by increasing the diameter of a part of the coil spring portion.
In this case, the pressing portion may be formed by increasing the diameter of the middle of a main body of the coil spring portion.
The pressing portion may be formed by increasing the diameter of both ends of a main body of the compression coil spring.
The sheet-pressing member 23 is constructed such that the eddy-current shaped pressing portion (e.g., a flat spiral spring) 23a of large diameter flexibly presses the slip sheet S against the sheet feed roller. With this ffeature, in design, a spring constant of it measured in the pressing direction may be set to be small when comparing with the conventional one.
This fact implies that even if dimensional variation of the manufactured sheet-pressing menibers 23 is relatively large, a variation of pressing forces of the sheet-pressing members, which impart onto the slip sheet S, is reduced.
Thus, the sheet feeding mechanism, an appropriate pressing force may stably be imparted onto the slip sheet S by properly selecting such factors as the effective number of turns and the diameter of the coil portion of the sheet-pressing member, and a material of the sheet-pressing member.
The sheet-pressing member t:akes an integral form. The feature of the integral form contributes to reduction of the number of required component parts and size reduction, and further easy assembling.
Thus, the sheet feeding mechanism of the invention, which is simple in construction, can stabiy impart a pressing force of an optimum magnitude onto the sheet while being free from external factors such as assembling accuracy and medium or paper thickness.
The ink jet printer equipped with the thus constructed sheet feeding mechanism succeeds in solving the wet-ink transfer problem in which ink is transferred from the sheet feeding mechanism to a printing paper immediately after it is printed, viz. , the paper bearing printed characters, for example, which are still wet since it is not fixed. Further, the printer is capable of stably feeding the printing paper and hence printing at high print quality.
Further, according to the present invention, the printer comprises a printhead for printing characters, for example, on a sheet moving relatively to the pririthead by ejecting ink drops through ink discharging orifices; and sheet-pressing members having pressing portions, located near to the discharging orifices, for pressing on the sheet at their positions not in contact with the ink of the characters immediately after printed, the positions being spaced apart from the ink discharging orifices, the sheet-pressing members each including a coil spring portion formed by spirally coiling an elastic wire so that the wire rings formed when coiled are brought into close contact with one another, and each the pressing portion being formed by increasing the diameter of a part of the coil spring portion.
With such a construction, the sheet, even if it is bent, does not come in contact with the nozzle face since it is separated by the sheet-pressing members. Therefore, no ink is transferred to the slip sheet S.
The pressing portions do not come in contact with the printed characters, for example, being still wet on the sheet.
Therefore, the printer is free from ink sticking problem arising from the rubbing of the sheet with the sheet-pressing members.
BACKGROUND OF THE INVENTION
The present invention relates to a sheet feeding mechanism in use with an ink jet printer, for example, and more particularly to a sheet feeding mechanism including an object pressing member for pressing a printed sheet.
To print by an ink jet printer, the nozzle orifices of a printhead selectively eject ink drops onto a printing paper in accordance with print information while synchronizing with a relative movement of a printhead relative to a printing paper.
Generally, to feed a printing paper in the printer, the printing paper is nipped by a pair of paper-feed rollers, and one of the paired rollers is rotated.
In the case of the ink jet pririter, characters, for example, printed on the printing paper are not fixed. Accordingly, when the printed paper is pressed against the rollers, ink of the printed characters is still wet. The wet ink sticks onto the roller, and is transferred from the roller to the sheet or paper.
An ink jet printer designeci to solve the ink sticking problem is disclosed in JP-A-2-41277.
In the ink jet printer, the sheet is held by pressing the medium on the sheet feed roller. Therefore, the ink jet printer indispensably includes a sheet-pressing member having a, spur gear with sharp teeth on the shaft.
The sheet-pressing member iz;designed to act elastically to the spur gear or the shaft, and the thus designed member presses the printing paper against the sheet feed roller.
A contact area where the spur gear is in contact with the paper is small in the ink jet printer using the thus constructed sheet-pressing member. Therefore, rio ink transfer to the paper takes place in such a printer.
The sheet-pressing member of the printer takes the form of a bar or a plate, and the thus shaped member, while being bent, presses the sheet against the sheet feed roller.
The sheet-pressing member has a large spring constant, and inevitably suffers from dimensional variations. For this reason, work to properly set a pressing force is very difficult.
Where the pressing force is too large, an excessive load acts on the paper being fed. On the other hand, where it is too small, a sheet feeding force is insufficient. Either case leads to degradation of print quality.
SUMMARY OF THE INVENTION
Accordingly, an object of the present invention is to provide an ink jet printer with a sheet feeding mechanism which imparts an optimum pressing force onto a sheet being transported.
To achieve the above object, there is provided an object pressing member for pressing a sheet being transported along a transport path, the object-pressing member including a pressing portion of large diameter being shaped like an eddy current by spirally coiling an elastic wire.
A sheet feeding mechanism includes a sheet feed roller and a sheet-pressing member disposed so as to press the sheet feed roller, the sheet-pressing member including a pressing portion of large diameter being shaped like an eddy current by spirally coiling an elastic wire.
A printer for printing on a sheet set therein, the printer having a printhead, and a sheet feeding mechanism disposed downward of the printhead when viewed in a sheet feeding direction, wherein the sheet feeding mechanism comprises a sheet feed roller for feeding a sheet printed by the printhead in a predetermined direction; and a sheet-pressing member disposed so as to press the sheet feed roller, the sheet-pressing member including a pressing portion of large diameter being shaped like an eddy current by spirally coiling an elastic wire.
The sheet-pressing member includes a coil spring portion formed by spirally coiling the wire so that the wire rings formed are brought into close contact with one another, and the pressing portion is formed by increasing the diameter of a part of the coil spring portion.
In this case, the pressing portion may be formed by increasing the diameter of the middle of a main body of the coil spring portion.
The pressing portion may be formed by increasing the diameter of both ends of a main body of the compression coil spring.
The sheet-pressing member 23 is constructed such that the eddy-current shaped pressing portion (e.g., a flat spiral spring) 23a of large diameter flexibly presses the slip sheet S against the sheet feed roller. With this ffeature, in design, a spring constant of it measured in the pressing direction may be set to be small when comparing with the conventional one.
This fact implies that even if dimensional variation of the manufactured sheet-pressing menibers 23 is relatively large, a variation of pressing forces of the sheet-pressing members, which impart onto the slip sheet S, is reduced.
Thus, the sheet feeding mechanism, an appropriate pressing force may stably be imparted onto the slip sheet S by properly selecting such factors as the effective number of turns and the diameter of the coil portion of the sheet-pressing member, and a material of the sheet-pressing member.
The sheet-pressing member t:akes an integral form. The feature of the integral form contributes to reduction of the number of required component parts and size reduction, and further easy assembling.
Thus, the sheet feeding mechanism of the invention, which is simple in construction, can stabiy impart a pressing force of an optimum magnitude onto the sheet while being free from external factors such as assembling accuracy and medium or paper thickness.
The ink jet printer equipped with the thus constructed sheet feeding mechanism succeeds in solving the wet-ink transfer problem in which ink is transferred from the sheet feeding mechanism to a printing paper immediately after it is printed, viz. , the paper bearing printed characters, for example, which are still wet since it is not fixed. Further, the printer is capable of stably feeding the printing paper and hence printing at high print quality.
Further, according to the present invention, the printer comprises a printhead for printing characters, for example, on a sheet moving relatively to the pririthead by ejecting ink drops through ink discharging orifices; and sheet-pressing members having pressing portions, located near to the discharging orifices, for pressing on the sheet at their positions not in contact with the ink of the characters immediately after printed, the positions being spaced apart from the ink discharging orifices, the sheet-pressing members each including a coil spring portion formed by spirally coiling an elastic wire so that the wire rings formed when coiled are brought into close contact with one another, and each the pressing portion being formed by increasing the diameter of a part of the coil spring portion.
With such a construction, the sheet, even if it is bent, does not come in contact with the nozzle face since it is separated by the sheet-pressing members. Therefore, no ink is transferred to the slip sheet S.
The pressing portions do not come in contact with the printed characters, for example, being still wet on the sheet.
Therefore, the printer is free from ink sticking problem arising from the rubbing of the sheet with the sheet-pressing members.
The sheet-pressing members may include pressing portions for pressing down both sides of a region on the sheet immediately afte:r characters, for example, are printed on the sheet.
In the construction, the sheet is pressed down at a plurality of positions by use of the pressing portions, and hence the sheet :is reliably held down.
The thus constructed printer may include a wiper means for wiping ink stuck onto the ink discharging orifices while moving relatively to the ink discharging orifices, wherein the sheet-pressing members include pressing portions for pressing down the sheet while being located at positions out of a region including the ink discharging orifices when viewed in the wiping direction of the wiper means.
In the construction, the sheet-pressing members are located at positions out of a region including the ink discharging orifices when viewed in the wiping direction of the wiper means. Therefore, there is no chance that the pairs of the pressing portions of the sheet-pressing members come in contact with the wiper means, and hence that the wiper means is worn with those members. No degradation of the wiping ability of the wiper means results.
In one aspect, the present invention provides an object pressing member f'or pressing an object being transported along a transport. path, said object pressing member formed by an electric wire, having a helix section with a generally constant diameter about a central axis, and at least one spiral section generally in a plane perpendicular to said axis and having an outer diameter greater than said constant diameter.
In the construction, the sheet is pressed down at a plurality of positions by use of the pressing portions, and hence the sheet :is reliably held down.
The thus constructed printer may include a wiper means for wiping ink stuck onto the ink discharging orifices while moving relatively to the ink discharging orifices, wherein the sheet-pressing members include pressing portions for pressing down the sheet while being located at positions out of a region including the ink discharging orifices when viewed in the wiping direction of the wiper means.
In the construction, the sheet-pressing members are located at positions out of a region including the ink discharging orifices when viewed in the wiping direction of the wiper means. Therefore, there is no chance that the pairs of the pressing portions of the sheet-pressing members come in contact with the wiper means, and hence that the wiper means is worn with those members. No degradation of the wiping ability of the wiper means results.
In one aspect, the present invention provides an object pressing member f'or pressing an object being transported along a transport. path, said object pressing member formed by an electric wire, having a helix section with a generally constant diameter about a central axis, and at least one spiral section generally in a plane perpendicular to said axis and having an outer diameter greater than said constant diameter.
In another aspect, the present invention provides an object pressing member for pressing an object being transported along a transport path, said object pressing member formed by an elastic wire, having a cylindrical shaft portion formed by coiling the elastic wire into wire rings of generally constant diameter about a central axis so that the wire rings are brought into close contact with one another, and at least one spiral section generally in a plane perpendicular to said central axis and having an outer diameter greater than said constant diameter.
In a still further aspect, the present invention provides a sheet feeding mechanism for feeding a sheet along a transport path, comprising: a sheet feed roller; and a sheet-pressing member, disposed so as to press said sheet feed roller, said sheet-pressing member formed by an elastic wire, having a cylindrical shaft portion formed by coiling the elastic wire into wire rings of generally constant diameter about a central axis so that the wire rings are brought into close contact with one another, and at least one spiral section generally in a plane perpendicular to said central axis and having an outer diameter greater than said constant diameter.
In a further aspect, the present invention provides a printer for printing on a sheet set therein, said printer comprising: a printhead; a sheet feed roller, disposed downward of said printhead when viewed in a sheet feeding direction, for feeding a sheet printed by said printhead in a predetermined direction; and a sheet-pressing member, disposed so as to press down said sheet feed roller, said sheet-pressing member formed by an elastic wire, having a cylindrical shaft portion formed by coiling the elastic wire into wire rings of generally constant diameter about a central axis so that the wire rings are brought into close contact with one another, and at least one spiral section generally in a - 5a -plane perpendicular to said central axis and having an outer diameter greater than said constant diameter.
In a still further aspect, the present invention provides a printer comprising: a printhead for printing characters on a sheet moving relatively to the printhead by ejecting ink drops through ink discharging orifices; and sheet-pressing members, located near said discharging orifices, for pressing on the sheet at their positions not in contact with the ink of the characters immediately after printed, said positions being spaced apart from said ink discharging orifices, said sheet-pressing members formed by an elastic wire, having a cylindrical shaft portion formed by coiling the elastic wire into wire rings of generally constant diameter about a central axis so that the wire rings are brought into close contact with one another, and at least one spiral section generally in a plane perpendicular to said central axis and having an outer diameter greater than said constant diameter.
In a further aspect, the present invention provides a printer for printing on a sheet set therein, said printer comprising: a printhead; a guide member disposed downstream of said printhead when viewed in a sheet feeding direction and in a side where said printhead is located with respect to said sheet, said guide member defining a part of a paper transporting passage; and a spring for guiding said sheet in a direction in which said sheet is apart from said guide member, said spring formed by an elastic wire, having a cylindrical shaft portion formed by coiling the elastic wire into wire rings of generally constant diameter about a central axis so that the wire rings are brought into close contact with one another, and at least one spiral section generally in a plane perpendicular to said axis and having an outer diameter greater than said constant diameter.
In a still further aspect, the present invention provides a printer comprising: a printhead; a guide member disposed - 5b -downstream of said printhead when viewed in a sheet feeding direction along a paper transporting passage, said guide member defining a part of said paper transporting passage; and a spring at least partially protruded into said paper transporting passage, said spring having a cylindrical shaft portion formed by coiling an elastic wire into wire rings of generally constant diameter about a central axis so that the wire rings are brought into close contact with one another, and at least one spiral section generally in a plane perpendicular to said central axis and having an outer diameter greater than said constant diameter.
In a further aspect, the present invention provides a paper guide for a sheet feeding mechanism, said paper guide comprising:
a guide plate having a surface along which a sheet is to be transported; and a spring supported by said guide plate, said spring having a cylindrical shaft portion formed by coiling an elastic wire into wire rings of generally constant diameter about a central axis so that the wire rings are brought into close contact with one another, and at least one spiral section generally in a plane perpendicular to said central axis and having an outer diameter greater than said constant diameter, said spiral section being partially protruded from said surface of said guide plate to be contactable with said sheet.
In a still further aspect, the present invention provides a pressing member for pressing an object being transported along a transport path, said pressing member (23; 123) including a cylindrical shaft portion (23b, 23c; 123b) formed by coiling an elastic wire into wire rings of substantially constant diameter about a central axis so that the wire rings are brought into close contact with one another, and a pressing portion (23a; 123a) formed by spirally coiling said wire to an outer diameter larger than the diameter of the shaft portion.
- 5c -BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a perspective view showing an outline of an ink jet printer equipped with a sheet feeding mechanism that is a first embodiment of the present invention;
Fig. 2 is a perspective view showing a key portion of the sheet feeding mechanism of the first embodiment;
Fig. 3 is a perspective view showing a sheet-pressing member assembled into the sheet feeding mechanism of Fig. 2;
Fig. 4 is a perspective view showing a key portion of another sheet feeding mechanism that is a second embodiment of the invention;
- 5d -Fig. 5 is a perspective view showing another sheet-pressing member assembled into the sheet feeding mechanism constructed according to a third embodiment of the invention;
Fig. 6 is a perspective view showing a key portion of a fourth embodiment of a sheet-pressing member according to the present invention. Fig. 6A is a perspective view showing a printing unit of the printer of the fourth embodiment. Fig. 6B
is a diagram showing a positional relationship between a nozzle face of a print head and a sheet-pressing member in the printer.
Fig. 7 is a perspective view showing a printing unit in a fifth embodiment of the inventicn.
DESCRIPTION OF THE PREE'ERRED EMBODIMENTS
The prefered embodiments of the present invention, which are believed to be preferred, will be described in detail with reference to the accompanying drawings.
Fig. 1 is a perspective view showing an outline of an ink jet printer equipped with a sheet feeding mechanism that is a first embodiment of the present inventio.n.
Fig. 2 is a perspective view showing a key portion of the sheet feeding mechanism of the first embodiment. Fig. 3 is a perspective view showing a sheet-pressing member assembled into the sheet feeding mechanism of Fig. 2.
As shown in Fig. 1, in a printer 1 constructed=according to the invention, a printing unit 4 is disposed in a front portion within a main body case 2. The prir-ting unit 4 prints on a slip sheet S or a check sheet P referred to as a slip sheet S. The case 2 is made of resin.
The printing unit 4 prints in a known ink jet printing manner. The printing unit 4 is movable along a guide shaft 6 within a limited range between both side ends of a main body frame 5 made of metal, for example. The guide shaft 6 is transversely mounted on the frame S.
In a still further aspect, the present invention provides a sheet feeding mechanism for feeding a sheet along a transport path, comprising: a sheet feed roller; and a sheet-pressing member, disposed so as to press said sheet feed roller, said sheet-pressing member formed by an elastic wire, having a cylindrical shaft portion formed by coiling the elastic wire into wire rings of generally constant diameter about a central axis so that the wire rings are brought into close contact with one another, and at least one spiral section generally in a plane perpendicular to said central axis and having an outer diameter greater than said constant diameter.
In a further aspect, the present invention provides a printer for printing on a sheet set therein, said printer comprising: a printhead; a sheet feed roller, disposed downward of said printhead when viewed in a sheet feeding direction, for feeding a sheet printed by said printhead in a predetermined direction; and a sheet-pressing member, disposed so as to press down said sheet feed roller, said sheet-pressing member formed by an elastic wire, having a cylindrical shaft portion formed by coiling the elastic wire into wire rings of generally constant diameter about a central axis so that the wire rings are brought into close contact with one another, and at least one spiral section generally in a - 5a -plane perpendicular to said central axis and having an outer diameter greater than said constant diameter.
In a still further aspect, the present invention provides a printer comprising: a printhead for printing characters on a sheet moving relatively to the printhead by ejecting ink drops through ink discharging orifices; and sheet-pressing members, located near said discharging orifices, for pressing on the sheet at their positions not in contact with the ink of the characters immediately after printed, said positions being spaced apart from said ink discharging orifices, said sheet-pressing members formed by an elastic wire, having a cylindrical shaft portion formed by coiling the elastic wire into wire rings of generally constant diameter about a central axis so that the wire rings are brought into close contact with one another, and at least one spiral section generally in a plane perpendicular to said central axis and having an outer diameter greater than said constant diameter.
In a further aspect, the present invention provides a printer for printing on a sheet set therein, said printer comprising: a printhead; a guide member disposed downstream of said printhead when viewed in a sheet feeding direction and in a side where said printhead is located with respect to said sheet, said guide member defining a part of a paper transporting passage; and a spring for guiding said sheet in a direction in which said sheet is apart from said guide member, said spring formed by an elastic wire, having a cylindrical shaft portion formed by coiling the elastic wire into wire rings of generally constant diameter about a central axis so that the wire rings are brought into close contact with one another, and at least one spiral section generally in a plane perpendicular to said axis and having an outer diameter greater than said constant diameter.
In a still further aspect, the present invention provides a printer comprising: a printhead; a guide member disposed - 5b -downstream of said printhead when viewed in a sheet feeding direction along a paper transporting passage, said guide member defining a part of said paper transporting passage; and a spring at least partially protruded into said paper transporting passage, said spring having a cylindrical shaft portion formed by coiling an elastic wire into wire rings of generally constant diameter about a central axis so that the wire rings are brought into close contact with one another, and at least one spiral section generally in a plane perpendicular to said central axis and having an outer diameter greater than said constant diameter.
In a further aspect, the present invention provides a paper guide for a sheet feeding mechanism, said paper guide comprising:
a guide plate having a surface along which a sheet is to be transported; and a spring supported by said guide plate, said spring having a cylindrical shaft portion formed by coiling an elastic wire into wire rings of generally constant diameter about a central axis so that the wire rings are brought into close contact with one another, and at least one spiral section generally in a plane perpendicular to said central axis and having an outer diameter greater than said constant diameter, said spiral section being partially protruded from said surface of said guide plate to be contactable with said sheet.
In a still further aspect, the present invention provides a pressing member for pressing an object being transported along a transport path, said pressing member (23; 123) including a cylindrical shaft portion (23b, 23c; 123b) formed by coiling an elastic wire into wire rings of substantially constant diameter about a central axis so that the wire rings are brought into close contact with one another, and a pressing portion (23a; 123a) formed by spirally coiling said wire to an outer diameter larger than the diameter of the shaft portion.
- 5c -BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a perspective view showing an outline of an ink jet printer equipped with a sheet feeding mechanism that is a first embodiment of the present invention;
Fig. 2 is a perspective view showing a key portion of the sheet feeding mechanism of the first embodiment;
Fig. 3 is a perspective view showing a sheet-pressing member assembled into the sheet feeding mechanism of Fig. 2;
Fig. 4 is a perspective view showing a key portion of another sheet feeding mechanism that is a second embodiment of the invention;
- 5d -Fig. 5 is a perspective view showing another sheet-pressing member assembled into the sheet feeding mechanism constructed according to a third embodiment of the invention;
Fig. 6 is a perspective view showing a key portion of a fourth embodiment of a sheet-pressing member according to the present invention. Fig. 6A is a perspective view showing a printing unit of the printer of the fourth embodiment. Fig. 6B
is a diagram showing a positional relationship between a nozzle face of a print head and a sheet-pressing member in the printer.
Fig. 7 is a perspective view showing a printing unit in a fifth embodiment of the inventicn.
DESCRIPTION OF THE PREE'ERRED EMBODIMENTS
The prefered embodiments of the present invention, which are believed to be preferred, will be described in detail with reference to the accompanying drawings.
Fig. 1 is a perspective view showing an outline of an ink jet printer equipped with a sheet feeding mechanism that is a first embodiment of the present inventio.n.
Fig. 2 is a perspective view showing a key portion of the sheet feeding mechanism of the first embodiment. Fig. 3 is a perspective view showing a sheet-pressing member assembled into the sheet feeding mechanism of Fig. 2.
As shown in Fig. 1, in a printer 1 constructed=according to the invention, a printing unit 4 is disposed in a front portion within a main body case 2. The prir-ting unit 4 prints on a slip sheet S or a check sheet P referred to as a slip sheet S. The case 2 is made of resin.
The printing unit 4 prints in a known ink jet printing manner. The printing unit 4 is movable along a guide shaft 6 within a limited range between both side ends of a main body frame 5 made of metal, for example. The guide shaft 6 is transversely mounted on the frame S.
Pulleys 8 and 9 are rotatably supported at both sides of the frame 5. An endless belt 7 is wound on the pulleys 8 and 9.
The printing unit 4 is fastened to a part of the endless belt 7.
The printing unit 4 is disposed such that a printhead 4a of the printing unit is directed to the inside of the case 2.
A guide face 3 is disposed within the case 2 while confronting the printhead 4a of the printing unit 4. The guide face 3 is provided for guiding a slip sheet S.
A platen 10 is located on the inner side of the guide face 3. A slip sheet S is moved through a gap between the platen 10 and the printhead 4a of the printing unit 4. To print, the printhead 4a ejects ink drops onto the slip sheet S moving through the gap.
A cap 4b is provided adjacent to the platen 10. When the printer rests for a predetermined time period or longer, the printing unit 4 is moved to the position of the cap 4b to cover the nozzle orifices of the printhead 4a thereof with the cap 4b.
With use of the cap 4b, the nozzles of the printhead 4a can be kept wet even when the printer is left not used for a long time.
A wiper (ink wiping means) 4c is further provided at a position near the cap 4b. The wiper 4c is provided for wiping ink off the nozzle-orifice array 42 of the printhead 4a. the wiper 4c is formed with an elastic plate-like member made of resin, for example.
A paper-insertion port 32 is formed in the front side of the main body of the printer 1. Slip sheets S are inserted through the paper-insertion port 32 into the printer inside. A rail-like guide member 33 is extended along one of side ends of the paper-insertion port 32. The rail-].ike guide member 33 guides a slip sheet S when it is inserted into the printer through the port 32.
Paper transporting means 31 is provided within the main body of the printer 1. The paper transporting means 31 transports a slip sheet S, which comes in through the paper-insertion port 32, toward the printing unit 4.
A construction of the paper transporting means 31 is: a couple of rotary shafts each having a plurality of rollers fixedly mounted thereon in a state that the rollers are spatially separated in the axial direction, are coupled. such that the rollers of the shafts are aligned to form pairs of rollers each pair of rollers being in contact with each other. In Fig. 1, one roller shaft having a couple of rollers 31a mounted thereon is typically illustrated for simplicity of illustration. The roller shaft is oriented in a paper width direction, i. e., perpendicular to a sheet feeding direction A.
A plurality of sheet feedinq mechanisms 20, which will be described in detail later, are disposed in the upper portion of the printer main body, specifically at positions adjacent to the platen 10 and located downstream when viewed in the sheet feeding direction A. A discharge outlet 13 is formed located downstream of the sheet feeding mechanism 20 when viewed in the sheet feeding direction A. A printed slip sheet S is discharged through the discharge outlet 13.
A roll paper R is located iri the rear portion within the main body case 2 of the printer 1. A paper exit port 12 is provided in the upper portion within the case 2. The leading end of the roll paper R is led out of the paper exit port 12. The roll paper R passes through a paper transporting path, which is different from a transporting path of the slip sheet S, although when the printer prints on the roll paper R, the roll paper R passes through the gap between the printhead 4a of the printing unit 4 and the platen 10.
As shown in Figs. 1 and 2, each sheet feeding mechanism 20 includes a sheet feed roller 22 and a sheet-pressing member 23.
The sheet feed roller 22 is coupled with a paper-feeding drive motor (not shown). The sheet-press:_ng member 23 holds the slip sheet S being transported by pressing down it on the sheet feed roller 22. The sheet-pressing member 23 is supported with a guide member 21 for guiding a slip sheet: S.
The guide member 21 consists of a metal plate-like member shaped, by pressing, for example, t:o have an introducing portion 21d and claw-like pieces 21a. The introducing portion 21d is provided for introducing the slip sheet S. The claw-like pieces 21a are for supporting and holding the sheet-pressing member 23.
The guide member 21, which is mounted on the frame 5, is disposed along the guide face 3 of the printfar 1 and facing the sheet feed roller 22 with a predetermined space being present therebetween.
The introducing portion 21d, which occupies an upstream end portion (when viewed in the sheet feeding direction A) of the guide member 21, is slanted in a direction in which its distance from the printer guide face 3 increases.
Three holes 21A, 21B and 21C are formed in the guide member 21 while being arrayed in the paper width direction. Claw-like pieces 21a1 and 21a2, and 21c1 and 21c2 are extended from the peripheral edges of the holes 21A,and 21C. The claw-like pieces 21a1 and 21a2, and 21c1 and 21c2 support the side and upper portions of the sheet-pressing member 23. Coupling supports 21b1 and 21b2 are formed at portions between the holes 21A and 21B and between the holes 21B and 21C, respectivel.y.
The sheet-pressing member 23 includes a spring body, which consists of a spring by spirally coiling a wire of stainless steel, for example. The spring body 23A of the sheet-pressing member 23 includes a disc-like pressing portion 23a and cylindrical shaft portions 23b and 23c continuing to the ends of the pressing portion 23a. The pressing portion 23a, occtipying the central portion of the spring body, is formed like an eddy current. The shaft portions 23b and 23c are each formed so that the! wire rings formed are brought into close contact with one another oy an initial tension. Those portions 23a, 23b and 23c are formed with a single wire in an integral form.
As shown in Fig. 3, the pressing portion 23a of the sheet-pressing member 23 is shaped; like a disc when viewed from side. It takes the form of a body formed by coupling together two cones together such that the bottom surfaces of them are in contact with each other. The outside diameter (diameter) of the pressing portion 23a is larger than that of the cylindrical shaft portions 23b and 23c. A contact portion 23d as the outermost circumferential edge of the pressing portion 23a is formed with one or two wires so as to reduce a contact area where it contacts with the slip sheet S. In the embodiment, the diameter of the cylindrical shaft portion 23b is selected to be equal to that of the shaft portion 23c.
The sheet-pressing member 23 may be manufactured by a manufacturing method using an automatic coiling machine.
The manufacturing process is a coiling method in which a wire for a coil spring travels tracing a predetermined path while being fed by a feed roller, and duri.ng the travel of the wire, it is curved at a predetermined curvature and twisted at a predetermined torsion. The diameter of a coil is varied by changing a position of a coiling piri set in the width of the wire traveling path.
In the method for manufacturing the sheet-pressing member employed, a coiling pin (not shown) is fixed to a predetermined position. One shaft portion 23b is first formed. Then, pressing portion 23a, larger in diameter than the shaft portion 23b, is formed in a manner that the coiling pin is gradually moved apart from the axial center of the coil, and then moved toward the axial center of the coil. Subsequently, the coiling pin is fixed at a predetermined position (the same position as the position used for forming the shaft portion 23b), and the other shaft portion 23c is formed in a similar manner.
The printing unit 4 is fastened to a part of the endless belt 7.
The printing unit 4 is disposed such that a printhead 4a of the printing unit is directed to the inside of the case 2.
A guide face 3 is disposed within the case 2 while confronting the printhead 4a of the printing unit 4. The guide face 3 is provided for guiding a slip sheet S.
A platen 10 is located on the inner side of the guide face 3. A slip sheet S is moved through a gap between the platen 10 and the printhead 4a of the printing unit 4. To print, the printhead 4a ejects ink drops onto the slip sheet S moving through the gap.
A cap 4b is provided adjacent to the platen 10. When the printer rests for a predetermined time period or longer, the printing unit 4 is moved to the position of the cap 4b to cover the nozzle orifices of the printhead 4a thereof with the cap 4b.
With use of the cap 4b, the nozzles of the printhead 4a can be kept wet even when the printer is left not used for a long time.
A wiper (ink wiping means) 4c is further provided at a position near the cap 4b. The wiper 4c is provided for wiping ink off the nozzle-orifice array 42 of the printhead 4a. the wiper 4c is formed with an elastic plate-like member made of resin, for example.
A paper-insertion port 32 is formed in the front side of the main body of the printer 1. Slip sheets S are inserted through the paper-insertion port 32 into the printer inside. A rail-like guide member 33 is extended along one of side ends of the paper-insertion port 32. The rail-].ike guide member 33 guides a slip sheet S when it is inserted into the printer through the port 32.
Paper transporting means 31 is provided within the main body of the printer 1. The paper transporting means 31 transports a slip sheet S, which comes in through the paper-insertion port 32, toward the printing unit 4.
A construction of the paper transporting means 31 is: a couple of rotary shafts each having a plurality of rollers fixedly mounted thereon in a state that the rollers are spatially separated in the axial direction, are coupled. such that the rollers of the shafts are aligned to form pairs of rollers each pair of rollers being in contact with each other. In Fig. 1, one roller shaft having a couple of rollers 31a mounted thereon is typically illustrated for simplicity of illustration. The roller shaft is oriented in a paper width direction, i. e., perpendicular to a sheet feeding direction A.
A plurality of sheet feedinq mechanisms 20, which will be described in detail later, are disposed in the upper portion of the printer main body, specifically at positions adjacent to the platen 10 and located downstream when viewed in the sheet feeding direction A. A discharge outlet 13 is formed located downstream of the sheet feeding mechanism 20 when viewed in the sheet feeding direction A. A printed slip sheet S is discharged through the discharge outlet 13.
A roll paper R is located iri the rear portion within the main body case 2 of the printer 1. A paper exit port 12 is provided in the upper portion within the case 2. The leading end of the roll paper R is led out of the paper exit port 12. The roll paper R passes through a paper transporting path, which is different from a transporting path of the slip sheet S, although when the printer prints on the roll paper R, the roll paper R passes through the gap between the printhead 4a of the printing unit 4 and the platen 10.
As shown in Figs. 1 and 2, each sheet feeding mechanism 20 includes a sheet feed roller 22 and a sheet-pressing member 23.
The sheet feed roller 22 is coupled with a paper-feeding drive motor (not shown). The sheet-press:_ng member 23 holds the slip sheet S being transported by pressing down it on the sheet feed roller 22. The sheet-pressing member 23 is supported with a guide member 21 for guiding a slip sheet: S.
The guide member 21 consists of a metal plate-like member shaped, by pressing, for example, t:o have an introducing portion 21d and claw-like pieces 21a. The introducing portion 21d is provided for introducing the slip sheet S. The claw-like pieces 21a are for supporting and holding the sheet-pressing member 23.
The guide member 21, which is mounted on the frame 5, is disposed along the guide face 3 of the printfar 1 and facing the sheet feed roller 22 with a predetermined space being present therebetween.
The introducing portion 21d, which occupies an upstream end portion (when viewed in the sheet feeding direction A) of the guide member 21, is slanted in a direction in which its distance from the printer guide face 3 increases.
Three holes 21A, 21B and 21C are formed in the guide member 21 while being arrayed in the paper width direction. Claw-like pieces 21a1 and 21a2, and 21c1 and 21c2 are extended from the peripheral edges of the holes 21A,and 21C. The claw-like pieces 21a1 and 21a2, and 21c1 and 21c2 support the side and upper portions of the sheet-pressing member 23. Coupling supports 21b1 and 21b2 are formed at portions between the holes 21A and 21B and between the holes 21B and 21C, respectivel.y.
The sheet-pressing member 23 includes a spring body, which consists of a spring by spirally coiling a wire of stainless steel, for example. The spring body 23A of the sheet-pressing member 23 includes a disc-like pressing portion 23a and cylindrical shaft portions 23b and 23c continuing to the ends of the pressing portion 23a. The pressing portion 23a, occtipying the central portion of the spring body, is formed like an eddy current. The shaft portions 23b and 23c are each formed so that the! wire rings formed are brought into close contact with one another oy an initial tension. Those portions 23a, 23b and 23c are formed with a single wire in an integral form.
As shown in Fig. 3, the pressing portion 23a of the sheet-pressing member 23 is shaped; like a disc when viewed from side. It takes the form of a body formed by coupling together two cones together such that the bottom surfaces of them are in contact with each other. The outside diameter (diameter) of the pressing portion 23a is larger than that of the cylindrical shaft portions 23b and 23c. A contact portion 23d as the outermost circumferential edge of the pressing portion 23a is formed with one or two wires so as to reduce a contact area where it contacts with the slip sheet S. In the embodiment, the diameter of the cylindrical shaft portion 23b is selected to be equal to that of the shaft portion 23c.
The sheet-pressing member 23 may be manufactured by a manufacturing method using an automatic coiling machine.
The manufacturing process is a coiling method in which a wire for a coil spring travels tracing a predetermined path while being fed by a feed roller, and duri.ng the travel of the wire, it is curved at a predetermined curvature and twisted at a predetermined torsion. The diameter of a coil is varied by changing a position of a coiling piri set in the width of the wire traveling path.
In the method for manufacturing the sheet-pressing member employed, a coiling pin (not shown) is fixed to a predetermined position. One shaft portion 23b is first formed. Then, pressing portion 23a, larger in diameter than the shaft portion 23b, is formed in a manner that the coiling pin is gradually moved apart from the axial center of the coil, and then moved toward the axial center of the coil. Subsequently, the coiling pin is fixed at a predetermined position (the same position as the position used for forming the shaft portion 23b), and the other shaft portion 23c is formed in a similar manner.
As shown in Fig. 2, one stiaft portion 23b of the sheet-pressing member 23 is grasped with the claw-like pieces 21a1 and 21a2, and the coupling support: 21b1, while the other shaft portion 23c is grasped with the claw-like pieces 21c1 and 21c2, and the coupling support 21b2. The thus grasped sheet-pressing member 23, while being angularly immovable, is held with the guide member 21.
The cylindrical shaft portions 23b and 23c of the sheet-pressing member 23, which are thus held, are somewhat bent, by the coupling support 21b1, between the claw-like pieces 21a1 and 21c1, whereby the sheet-pressing member 23 is immovable in the paper width direction.
The contact portion 23d of the pressing portion 23a of the sheet-pressing member 23 is protruded through the hole 21B of the guide member 21 to be in contact with the sheet feed roller 22, so that the shaft portions 23b and 23c are somewhat bent.
The sheet feeding mechanism for an ink jet printer is thus constructed. In operation, after subjected to printing by the printhead 4a in the printer 1, a slip sheet S is transported by the paper transporting means 31; guided by the introducing portion 21d of the guide member 21; and inserted into the space between the sheet feed roller 22 and the pressing portion 23a of the sheet-pressing member 23.
The pressing portion 23a presses the slip sheet S against the sheet feed roller 22, and is transported to the discharge outlet 13 with rotation of the sheet feed roller 22.
As recalled, the contact portion 23d of the pressing portion 23a is designed so as to have a small contact area where it contacts with the slip sheet S. Because of this, little ink is transferred to the slip sheet S during the sheet feeding.
The sheet-pressing member 23 is constructed such that the eddy-current shaped pressing portion 23a of large diameter flexibly presses the slip sheet S against the sheet feed roller.
The cylindrical shaft portions 23b and 23c of the sheet-pressing member 23, which are thus held, are somewhat bent, by the coupling support 21b1, between the claw-like pieces 21a1 and 21c1, whereby the sheet-pressing member 23 is immovable in the paper width direction.
The contact portion 23d of the pressing portion 23a of the sheet-pressing member 23 is protruded through the hole 21B of the guide member 21 to be in contact with the sheet feed roller 22, so that the shaft portions 23b and 23c are somewhat bent.
The sheet feeding mechanism for an ink jet printer is thus constructed. In operation, after subjected to printing by the printhead 4a in the printer 1, a slip sheet S is transported by the paper transporting means 31; guided by the introducing portion 21d of the guide member 21; and inserted into the space between the sheet feed roller 22 and the pressing portion 23a of the sheet-pressing member 23.
The pressing portion 23a presses the slip sheet S against the sheet feed roller 22, and is transported to the discharge outlet 13 with rotation of the sheet feed roller 22.
As recalled, the contact portion 23d of the pressing portion 23a is designed so as to have a small contact area where it contacts with the slip sheet S. Because of this, little ink is transferred to the slip sheet S during the sheet feeding.
The sheet-pressing member 23 is constructed such that the eddy-current shaped pressing portion 23a of large diameter flexibly presses the slip sheet S against the sheet feed roller.
With this feature, in design, a spring constant of it measured in the pressing direction may be set to be small when comparing with the conventional one.
This fact implies that even if dimensional variation of the manufactured sheet-pressing members 23, caused by their assembly accuracy difference and paper thickness difference, is relatively large, a variation of pressing forces of the sheet-pressing members, which impart ontc> the slip sheet S, is reduced.
Thus, the sheet-pressing member of the invention is capable of stably imparting an appropriate pressing force on the slip sheet S through a designer's proper selection of such factors as the effective number of turns and the diameter of the coil portion of the sheet-pressing member 23, and a material of the sheet-pressing member. In this respect, improved print quality results.
It is noted that the pressing portion 23a, and the cylindrical shaft portions 23b and 23c supporting the former, those portions being all used for the sheet-pressing by the sheet-pressing member 23, are integrally formed. This feature contributes to reduction of the number of required component parts and size reduction, and further easy assembling.
Further, a plurality of sheet-pressing members 23 are arrayed in the paper width direction. Therefore, the sheet feeding mechanism can stably feed slip sheets S of different,width dimensions.
Fig. 4 is a perspective view showing a key portion of another sheet feeding mechanism that is a second embodiment of the present invention. Fig. 5 is a perspective view showing another sheet-pressing member assembled into the sheet feeding mechanism constructed according to the third embodiment of the invention.
As shown in Fig. 4, a sheet feeding mechanism 120, as in the first embodiment, includes a stieet feed roller 122 and a sheet-pressing member 123. The sheet-pressing member 123 presses the slip sheet S against the sheet feed roller 122. The sheet-pressing member 123 is supported with a guide member 121 for guiding a slip sheet S.
Two holes 121A and 121B are formed in the guide member 121 while being arrayed in the paper width direction. Claw-like pieces 121a1 and 121a2, and 121c1 and 121c2 are extended from the peripheral edges of the holes 121A and 121B. The claw-like pieces 121al and 121a2, and 121c1 and 121c2 support the side and upper portions of the sheet-pressing member 123. A coupling supports 121b is formed at a portion between the holes 121A and 121B.
The sheet-pressing member 123, like the sheet-pressing member 23, includes a spring body 124A, which consists of a spring by spirally coiling a wire of stainless steel, for example.
As shown in Fig. 5, the sheet-processing member 123 includes a cylindrical shaft portion 123b and pressing portions 123a and 123c, each shaped like a disc when viewed from side, formed at both ends of the cylindrical shaft portion 123b. The shaft portion 123b is formed so that the wire rings formed are brought into close contact with one another by an initial tension.
The pressing portions 123a and 123c are each formed like an eddy current. Those portions 123a, 123b and 123c are formed with a single wire in an integral form.
As shown in Fig. 5, the pressing portions 123a and 123c of the sheet-pressing member 123 are each shaped like a cone of which the apex connects to the end of the cylindrical shaft portion 123b and the bottom surface is directed outside. The outside diameter (diameter) of each of the pressing portions 123a and 123c is larger than that of the cylindrical shaft portion 123b.
Contact portion 123d and 123e as the outermost circumferential edges of the pressing portions 123a and 123c are each formed with one or two wires so as to reduce a contact area where each of them contacts with the slip sheet S. In the embodiment, the diameter of the pressing portion 123b is equal to the of the pressing portion 123c.
The sheet-pressing member 123 may also be manufactured by a manufacturing method using an automatic coiling machine as in the above-mentioned embodiment.
As shown in Fig. 4, the shaft portion 123b of the sheet-pressing member 123 is grasped with the claw-like pieces 121a1 and 121a2, and 121c1 and 12c2, and the coupling support 121b1 of the guide member 121. The thus grasped sheet-pressing member 123, while being angularly immovable, is held with the guide member 121.
The cylindrical shaft portion 123b of the sheet-pressing member 123, while being somewhat bent, are held between the claw-like pieces 121a1 and 121c1, whereby the sheet-pressing member 123 is immovable in the paper width direction.
The contact portions 123d anci 123e of the pressing portions 123a and 123bc of the sheet-pressing member 123 are protruded through the holes 121A and 121B of the guide member 121 to be in contact with the sheet feed roller 122, so that the shaft portion 123b is somewhat bent.
The sheet-pressing member 123 of the second embodiment is also constructed such that the eddy-current shaped pressing portions 123a and 123c of large dianieter flexibly press the slip sheet Sagainst the sheet feedroller. Withthis feature,. in design, a spring constant of them in the pressing direction may be set to be small when comparing with the conventional one. This fact implies that even if dimensional variation of the manufactured sheet-pressing members 123, caused by their assembly accuracy difference and paper thickness difference, is relatively large, avariation of pressing forces of the sheet-pressing members, which impart onto the slip sheet S, is reduced.
The pressing portions 123a and 123c, and the cylindrical shaft portion 23b supporting them, those portions being all used for the sheet-pressing by the sheet-pressing member 23, are integrally formed. This feature contributes to reduction of the number of required component parts and size reduction, and further easy assembling.
A fourth embodiment of the present invention will be described with reference to Fig. 6. The fourth embodiment is a printer incorporating thereinto a sheet-pressing member constructed according to the present invention.
Fig. 6A is a perspective view showing a printing unit of the printer of thefourth embodiment. Fig.6Bisa diagramshowing a positional relationship between a nozzle face of a print head and a sheet-pressing member in the printer.
As shown in Fig. 6A, a printing unit 4 of the printer includes a carriage 40 which is movable along the guide shaft 6 in a direction X or in the opposite direction to the direction X.
A printhead 4a is provided on the f:ront side of the carriage 40.
A nozzle face 41 occupies a centrai_ portion of the printhead 4a.
Nozzle orifice array 42 are formed in this portion. To print, the nozzle orifice array 42 eject ink drops at given timings in accordance with print information, and prints characters, for example, on a slip sheet S.
A couple of sheet-pressing members 24 and 25 are respectively located upstream and downstream of the printhead 4a when viewed in the traveling direction X of the printhea,d 4a. The sheet-pressing members 24 and 25 are constructed with springs which are equal in construction. The sheet-pressing member 24 (25) includes a bar-like shaft portion 24a (25a), disc-like pressing portions 24b and 24c (25b and 25c) provided at both ends of the shaft portion 24a (25a) as in the embodiments already described, and a fixing portion 240 (250) . The sheet-pressing member 24 (25) is fixedly attached, at its fixing portion 240 (250), to the carriage 40.
This fact implies that even if dimensional variation of the manufactured sheet-pressing members 23, caused by their assembly accuracy difference and paper thickness difference, is relatively large, a variation of pressing forces of the sheet-pressing members, which impart ontc> the slip sheet S, is reduced.
Thus, the sheet-pressing member of the invention is capable of stably imparting an appropriate pressing force on the slip sheet S through a designer's proper selection of such factors as the effective number of turns and the diameter of the coil portion of the sheet-pressing member 23, and a material of the sheet-pressing member. In this respect, improved print quality results.
It is noted that the pressing portion 23a, and the cylindrical shaft portions 23b and 23c supporting the former, those portions being all used for the sheet-pressing by the sheet-pressing member 23, are integrally formed. This feature contributes to reduction of the number of required component parts and size reduction, and further easy assembling.
Further, a plurality of sheet-pressing members 23 are arrayed in the paper width direction. Therefore, the sheet feeding mechanism can stably feed slip sheets S of different,width dimensions.
Fig. 4 is a perspective view showing a key portion of another sheet feeding mechanism that is a second embodiment of the present invention. Fig. 5 is a perspective view showing another sheet-pressing member assembled into the sheet feeding mechanism constructed according to the third embodiment of the invention.
As shown in Fig. 4, a sheet feeding mechanism 120, as in the first embodiment, includes a stieet feed roller 122 and a sheet-pressing member 123. The sheet-pressing member 123 presses the slip sheet S against the sheet feed roller 122. The sheet-pressing member 123 is supported with a guide member 121 for guiding a slip sheet S.
Two holes 121A and 121B are formed in the guide member 121 while being arrayed in the paper width direction. Claw-like pieces 121a1 and 121a2, and 121c1 and 121c2 are extended from the peripheral edges of the holes 121A and 121B. The claw-like pieces 121al and 121a2, and 121c1 and 121c2 support the side and upper portions of the sheet-pressing member 123. A coupling supports 121b is formed at a portion between the holes 121A and 121B.
The sheet-pressing member 123, like the sheet-pressing member 23, includes a spring body 124A, which consists of a spring by spirally coiling a wire of stainless steel, for example.
As shown in Fig. 5, the sheet-processing member 123 includes a cylindrical shaft portion 123b and pressing portions 123a and 123c, each shaped like a disc when viewed from side, formed at both ends of the cylindrical shaft portion 123b. The shaft portion 123b is formed so that the wire rings formed are brought into close contact with one another by an initial tension.
The pressing portions 123a and 123c are each formed like an eddy current. Those portions 123a, 123b and 123c are formed with a single wire in an integral form.
As shown in Fig. 5, the pressing portions 123a and 123c of the sheet-pressing member 123 are each shaped like a cone of which the apex connects to the end of the cylindrical shaft portion 123b and the bottom surface is directed outside. The outside diameter (diameter) of each of the pressing portions 123a and 123c is larger than that of the cylindrical shaft portion 123b.
Contact portion 123d and 123e as the outermost circumferential edges of the pressing portions 123a and 123c are each formed with one or two wires so as to reduce a contact area where each of them contacts with the slip sheet S. In the embodiment, the diameter of the pressing portion 123b is equal to the of the pressing portion 123c.
The sheet-pressing member 123 may also be manufactured by a manufacturing method using an automatic coiling machine as in the above-mentioned embodiment.
As shown in Fig. 4, the shaft portion 123b of the sheet-pressing member 123 is grasped with the claw-like pieces 121a1 and 121a2, and 121c1 and 12c2, and the coupling support 121b1 of the guide member 121. The thus grasped sheet-pressing member 123, while being angularly immovable, is held with the guide member 121.
The cylindrical shaft portion 123b of the sheet-pressing member 123, while being somewhat bent, are held between the claw-like pieces 121a1 and 121c1, whereby the sheet-pressing member 123 is immovable in the paper width direction.
The contact portions 123d anci 123e of the pressing portions 123a and 123bc of the sheet-pressing member 123 are protruded through the holes 121A and 121B of the guide member 121 to be in contact with the sheet feed roller 122, so that the shaft portion 123b is somewhat bent.
The sheet-pressing member 123 of the second embodiment is also constructed such that the eddy-current shaped pressing portions 123a and 123c of large dianieter flexibly press the slip sheet Sagainst the sheet feedroller. Withthis feature,. in design, a spring constant of them in the pressing direction may be set to be small when comparing with the conventional one. This fact implies that even if dimensional variation of the manufactured sheet-pressing members 123, caused by their assembly accuracy difference and paper thickness difference, is relatively large, avariation of pressing forces of the sheet-pressing members, which impart onto the slip sheet S, is reduced.
The pressing portions 123a and 123c, and the cylindrical shaft portion 23b supporting them, those portions being all used for the sheet-pressing by the sheet-pressing member 23, are integrally formed. This feature contributes to reduction of the number of required component parts and size reduction, and further easy assembling.
A fourth embodiment of the present invention will be described with reference to Fig. 6. The fourth embodiment is a printer incorporating thereinto a sheet-pressing member constructed according to the present invention.
Fig. 6A is a perspective view showing a printing unit of the printer of thefourth embodiment. Fig.6Bisa diagramshowing a positional relationship between a nozzle face of a print head and a sheet-pressing member in the printer.
As shown in Fig. 6A, a printing unit 4 of the printer includes a carriage 40 which is movable along the guide shaft 6 in a direction X or in the opposite direction to the direction X.
A printhead 4a is provided on the f:ront side of the carriage 40.
A nozzle face 41 occupies a centrai_ portion of the printhead 4a.
Nozzle orifice array 42 are formed in this portion. To print, the nozzle orifice array 42 eject ink drops at given timings in accordance with print information, and prints characters, for example, on a slip sheet S.
A couple of sheet-pressing members 24 and 25 are respectively located upstream and downstream of the printhead 4a when viewed in the traveling direction X of the printhea,d 4a. The sheet-pressing members 24 and 25 are constructed with springs which are equal in construction. The sheet-pressing member 24 (25) includes a bar-like shaft portion 24a (25a), disc-like pressing portions 24b and 24c (25b and 25c) provided at both ends of the shaft portion 24a (25a) as in the embodiments already described, and a fixing portion 240 (250) . The sheet-pressing member 24 (25) is fixedly attached, at its fixing portion 240 (250), to the carriage 40.
The outside diameter of each of the pressing portions 24b and 24c (25b and 25c) of the sheet-pressing member 24 (25) is larger than the shaft portion 24a (25a) . AS shown in Fig. 6B, the pressing portions 24b and 24c (25b and 25c) of the sheet-pressing member 24 (25) protrude beyond the nozzle face 41 of the printhead 4a so as to come in contact with the platen 10.
The pressing portions 24b and 24c (25b and 25c) of the sheet-pressing member 24 (25) are respectively located at positions equally distanced from the nozzle orifice array 42.
The sheet-pressing members 24 and 25 may also be manufactured by a manufacturing method using an automatic coiling machine, as in the embodiments mentioned above.
As shown in Fig. 6A, the wiper 4c is provided while being oriented at a right angle to the guide shaft 6. In operation, the printing unit 4 is moved along the guide shaft 6 in the opposite direction to the direction X, while at the same time the wiper 4c is moved relatively to the printing unit 4 in the direction X, and wipes ink left on the nozzle orifice array 42 of the printhead 4a.
In the present embodiment, ~=he sheet-pressing members 24 and 25 are oriented in a direction Y perpendicular to the guide shaft 6.
As shown in Figs. 6A and 6B, the pairs of the pressing portions 24b, 24c and 25b, 25c of the sheet-pressing members 24 and 25 are located on both sides of a region a including the nozzle orifice array 42 when viewed in the wiping direction (direction X) of the wiper 4c, viz., at positions out of the region a.
In this case, the shaft portions 24a and 25a of the sheet-pressing members 24 and 25 are preferably selected so as to prevent those paired pressing portions 24b, 24c and 25b, 25c of the sheet-pressing members 24 and 25 from coming in contact with the wiper 4c when the wiper operates for wiping.
The pressing portions 24b and 24c (25b and 25c) of the sheet-pressing member 24 (25) are respectively located at positions equally distanced from the nozzle orifice array 42.
The sheet-pressing members 24 and 25 may also be manufactured by a manufacturing method using an automatic coiling machine, as in the embodiments mentioned above.
As shown in Fig. 6A, the wiper 4c is provided while being oriented at a right angle to the guide shaft 6. In operation, the printing unit 4 is moved along the guide shaft 6 in the opposite direction to the direction X, while at the same time the wiper 4c is moved relatively to the printing unit 4 in the direction X, and wipes ink left on the nozzle orifice array 42 of the printhead 4a.
In the present embodiment, ~=he sheet-pressing members 24 and 25 are oriented in a direction Y perpendicular to the guide shaft 6.
As shown in Figs. 6A and 6B, the pairs of the pressing portions 24b, 24c and 25b, 25c of the sheet-pressing members 24 and 25 are located on both sides of a region a including the nozzle orifice array 42 when viewed in the wiping direction (direction X) of the wiper 4c, viz., at positions out of the region a.
In this case, the shaft portions 24a and 25a of the sheet-pressing members 24 and 25 are preferably selected so as to prevent those paired pressing portions 24b, 24c and 25b, 25c of the sheet-pressing members 24 and 25 from coming in contact with the wiper 4c when the wiper operates for wiping.
In a printing operation, the printer moves the slip sheet S in the direction Y while moving the printing unit 4 in the direction X.
In this case, as shown in Fig. 6B, the slip sheet S is separated fromthe nozzle-orifice array 42 and pressed on the platen by the pressing portions 24b, 24c and 25b, 25c, which are located in the vicinity of the nozzle-orifice array 42. This structural feature prevents the slip sheet S, even if it is bent, from coming in contact with the nozzle face 41. As a result, no ink is 10 transferred to the slip sheet S, and hence a high quality print is secured.
Further, it is noted that the four pressing portions 24b, 24c and 25b, 25c are located at the positions equally distanced from the nozzle-orifice array 42. This feature holds the slip sheet S in a well-balancing manner.
Furthermore, it is noted that the pairs of the pressing portions 24b, 24c and 25b, 25c are located on both sides of the nozzle-orifice array 42 of the printhead 4a when viewed in the traveling direction (direction X) of the printhead 4a, and that those pairs of the pressing portions 24b, 24c and 25b, 25c are located on both sides of the slip sheet S when viewed in the sheet feeding direction Y. With this structure, those pairs of the pressing portions 24b, 24c and 25b, 25c do not come in contact with the printed characters, for example, being still wet on the slip sheet S irrespective of the moving ciirection of the carriage 40.
Therefore, the printer is free from ink sticking problem arising from the rubbing of the printed slip s:-ieet S with the sheet-pressing members 24 and 25.
Also in the embodiment, as shown Fig. 6A, the nozzle face 41 is wiped with the wiper 4c in a manner that the carriage 40 is moved in the direction X and hence the wiper 4c is moved relatively to the printhead 4a.
In this case, as shown in Fig. 6B, the slip sheet S is separated fromthe nozzle-orifice array 42 and pressed on the platen by the pressing portions 24b, 24c and 25b, 25c, which are located in the vicinity of the nozzle-orifice array 42. This structural feature prevents the slip sheet S, even if it is bent, from coming in contact with the nozzle face 41. As a result, no ink is 10 transferred to the slip sheet S, and hence a high quality print is secured.
Further, it is noted that the four pressing portions 24b, 24c and 25b, 25c are located at the positions equally distanced from the nozzle-orifice array 42. This feature holds the slip sheet S in a well-balancing manner.
Furthermore, it is noted that the pairs of the pressing portions 24b, 24c and 25b, 25c are located on both sides of the nozzle-orifice array 42 of the printhead 4a when viewed in the traveling direction (direction X) of the printhead 4a, and that those pairs of the pressing portions 24b, 24c and 25b, 25c are located on both sides of the slip sheet S when viewed in the sheet feeding direction Y. With this structure, those pairs of the pressing portions 24b, 24c and 25b, 25c do not come in contact with the printed characters, for example, being still wet on the slip sheet S irrespective of the moving ciirection of the carriage 40.
Therefore, the printer is free from ink sticking problem arising from the rubbing of the printed slip s:-ieet S with the sheet-pressing members 24 and 25.
Also in the embodiment, as shown Fig. 6A, the nozzle face 41 is wiped with the wiper 4c in a manner that the carriage 40 is moved in the direction X and hence the wiper 4c is moved relatively to the printhead 4a.
In connection with this, as recalled, the pairs of the pressing portions 24b, 24c and 25b, 25c of the sheet-pressing members 24 and 25 are located at positions out of the region a including the nozzle-orif ice array 42. Besides, there is no chance that the pairs of the pressing portions 24b, 24c and 25b, 25c of the sheet-pressing members 24 and 25 come in contact with the wiper 4c, and hence that the wiper 4c is worn with those members. No degradation of the wiping ability of the wiper 4c results.
Additionally, the present invention uses the sheet-pressing members 24 and 35 formed with spring members. Therefore, in design, a spring constant of them measured in the pressing direction may be set to be small when comparing with the conventional one. This entails reduction of a variation of pressing forces of the sheet-pressing members, which impart onto the slip sheet S, and hence stable aipplication of proper pressing forces to the slip sheet S and stable holding of the slip sheet S.
The integrally formed sheet-pressing members 24 and 25 are fixed to the carriage 40. With this, a large space is not required, and the printer is simple in construction and reduced in size.
A fifth embodiment of the present invention will be described with reference to Fig. 7. Fig. 7 is a perspective view showing a printing unit in the fifth embodiment. In the figure, like or equivalent portions are designated by like reference numerals in Fig. 6.
A mounting member 260 is used for mounting sheet-pressing members 24 and 25 respectively on the upstream and downstream sides of the printhead 4a when viewed in the traveling direction X of the printhead 4a. The mounting member 260 is made of resin. As shown, two fins 262 and an arm 261 are formed at each end of the mounting member 260 when viewed in the longitudinal direction. The arm 261 is used for holding the central portion of the sheet-pressing member 24 (25).
Additionally, the present invention uses the sheet-pressing members 24 and 35 formed with spring members. Therefore, in design, a spring constant of them measured in the pressing direction may be set to be small when comparing with the conventional one. This entails reduction of a variation of pressing forces of the sheet-pressing members, which impart onto the slip sheet S, and hence stable aipplication of proper pressing forces to the slip sheet S and stable holding of the slip sheet S.
The integrally formed sheet-pressing members 24 and 25 are fixed to the carriage 40. With this, a large space is not required, and the printer is simple in construction and reduced in size.
A fifth embodiment of the present invention will be described with reference to Fig. 7. Fig. 7 is a perspective view showing a printing unit in the fifth embodiment. In the figure, like or equivalent portions are designated by like reference numerals in Fig. 6.
A mounting member 260 is used for mounting sheet-pressing members 24 and 25 respectively on the upstream and downstream sides of the printhead 4a when viewed in the traveling direction X of the printhead 4a. The mounting member 260 is made of resin. As shown, two fins 262 and an arm 261 are formed at each end of the mounting member 260 when viewed in the longitudinal direction. The arm 261 is used for holding the central portion of the sheet-pressing member 24 (25).
Each of the fins 262 includes a guide face slanted in the traveling direction of the printhead 4a. With provision of the guide faces of the fins 262, the printhead 4a may smoothly move to the slip sheet while not catching the end of the slip sheet.
if the end of the slip sheet S is raised at a height longer than the radius of each of the pressing portions 24b and 24c, the end of the slip sheet is guided by the guide faces of the fins 262 and gradually held down on the platen 10 with the movement of the printhead 4a.
Claw-like members 263 are provided on the other end of the mounting member 260. Holes 40a are formed in the carriage 40 at such locations as to receives the claw-like members 263 of the mounting member 260. The claw-like members 263 and the holes 40a form a called snap-fit construction. With this construction of the mounting member 260, the sheet-pressing members 24 and 25 may easily be mounted on the printhead 4a. Further, the guide portions for preventing the printhead 4a from catching the end of the slip sheet may be formed at both ends of the printhead 4a.
It should be understood to those skilled in the art that the present invention is not limited to the above-mentioned embodiments, but may variously be changed, modified and altered within the true spirits of the invention.
For example, a plurality of pressing portions may be provided at proper positions of the coil spring, which,forms the shaft portion of the sheet-pressing member.
While in the above-mentioned embodiments, the sheet-pressing members are held while being angularly immovable with respect to the guide member, it may be held while being angularly movable.
In the fourth and fifth embodiments, the nozzle-orifice array 42 of the printhead is held at four points by use of two sheet-pressing members. So long as such a construction that the pressing porti ons are provided at both ends of the region a is used, the sheet may be hold by use of two or larger number of pressing portions. To hold down the recording or sheet reliably and in a well-balanced manner, it is preferable to use the medium holding construction employed in the above-mentioned embodiments.
While two pressing members are formed at both ends of the coil spring of the sheet-pressing niember in the fourth and fifth embodiments, three or larger number of pressing portions may be formed on one spring coil.
Additionally, it is evident that the sheet-pressing member constructed according to the invention may be applied to any mechanism requiring a stable pressure contact, in addition to the ink jet printer.
The invention is most operant in particular when it is applied to a mechanism for transporting a sheet having printed characters, for example, being not yet fixed or still wet, as in the ink jet printer.
As seen from the foregoing clescription, the sheet feeding mechanism of the invention is able to impart an optimum pressing force onto a sheet being fed, and he:zce provides a printer of high quality printing.
if the end of the slip sheet S is raised at a height longer than the radius of each of the pressing portions 24b and 24c, the end of the slip sheet is guided by the guide faces of the fins 262 and gradually held down on the platen 10 with the movement of the printhead 4a.
Claw-like members 263 are provided on the other end of the mounting member 260. Holes 40a are formed in the carriage 40 at such locations as to receives the claw-like members 263 of the mounting member 260. The claw-like members 263 and the holes 40a form a called snap-fit construction. With this construction of the mounting member 260, the sheet-pressing members 24 and 25 may easily be mounted on the printhead 4a. Further, the guide portions for preventing the printhead 4a from catching the end of the slip sheet may be formed at both ends of the printhead 4a.
It should be understood to those skilled in the art that the present invention is not limited to the above-mentioned embodiments, but may variously be changed, modified and altered within the true spirits of the invention.
For example, a plurality of pressing portions may be provided at proper positions of the coil spring, which,forms the shaft portion of the sheet-pressing member.
While in the above-mentioned embodiments, the sheet-pressing members are held while being angularly immovable with respect to the guide member, it may be held while being angularly movable.
In the fourth and fifth embodiments, the nozzle-orifice array 42 of the printhead is held at four points by use of two sheet-pressing members. So long as such a construction that the pressing porti ons are provided at both ends of the region a is used, the sheet may be hold by use of two or larger number of pressing portions. To hold down the recording or sheet reliably and in a well-balanced manner, it is preferable to use the medium holding construction employed in the above-mentioned embodiments.
While two pressing members are formed at both ends of the coil spring of the sheet-pressing niember in the fourth and fifth embodiments, three or larger number of pressing portions may be formed on one spring coil.
Additionally, it is evident that the sheet-pressing member constructed according to the invention may be applied to any mechanism requiring a stable pressure contact, in addition to the ink jet printer.
The invention is most operant in particular when it is applied to a mechanism for transporting a sheet having printed characters, for example, being not yet fixed or still wet, as in the ink jet printer.
As seen from the foregoing clescription, the sheet feeding mechanism of the invention is able to impart an optimum pressing force onto a sheet being fed, and he:zce provides a printer of high quality printing.
Claims (32)
1. An object pressing member for pressing an object being transported along a transport path, said object pressing member formed by an elastic wire, having a cylindrical shaft portion formed by coiling the elastic wire into wire rings of generally constant diameter about a central axis so that the wire rings are brought into close contact with one another, and at least one spiral section generally in a plane perpendicular to said central axis and having an outer diameter greater than said constant diameter.
2. The object pressing member according to claim 1, wherein said at least one spiral section is located at a middle portion of said cylindrical shaft portion.
3. The object pressing member according to claim 1, wherein at least one spiral section is located at a first end of said cylindrical shaft portion and an additional spiral section, generally in a plane perpendicular to said axis and having a diameter greater than said constant diameter, is located at a second end of said cylindrical shaft portion.
4. A sheet feeding mechanism for feeding a sheet along a transport path, comprising:
a sheet feed roller; and a sheet-pressing member, disposed so as to press said sheet feed roller, said sheet-pressing member formed by an elastic wire, having a cylindrical shaft portion formed by coiling the elastic wire into wire rings of generally constant diameter about a central axis so that the wire rings are brought into close contact with one another, and at least one spiral section generally in a plane perpendicular to said central axis and having an outer diameter greater than said constant diameter.
a sheet feed roller; and a sheet-pressing member, disposed so as to press said sheet feed roller, said sheet-pressing member formed by an elastic wire, having a cylindrical shaft portion formed by coiling the elastic wire into wire rings of generally constant diameter about a central axis so that the wire rings are brought into close contact with one another, and at least one spiral section generally in a plane perpendicular to said central axis and having an outer diameter greater than said constant diameter.
5. A sheet feeding mechanism according to claim 4, wherein said at least one spiral section is located at a middle portion of said cylindrical shaft portion.
6. A sheet feeding mechanism according to claim 4, wherein said at least one spiral section is located at a first end of said cylindrical shaft portion and an additional spiral section, generally in a plane perpendicular to said central axis and having a diameter greater than said constant diameter, is located at a second end of said cylindrical shaft portion.
7. A printer for printing on a sheet set therein, said printer comprising:
a printhead;
a sheet feed roller, disposed downward of said printhead when viewed in a sheet feeding direction, for feeding a sheet printed by said printhead in a predetermined direction; and a sheet-pressing member, disposed so as to press down said sheet feed roller, said sheet-pressing member formed by an elastic wire, having a cylindrical shaft portion formed by coiling the elastic wire into wire rings of generally constant diameter about a central axis so that the wire rings are brought into close contact with one another, and at least one spiral section generally in a plane perpendicular to said central axis and having an outer diameter greater than said constant diameter.
a printhead;
a sheet feed roller, disposed downward of said printhead when viewed in a sheet feeding direction, for feeding a sheet printed by said printhead in a predetermined direction; and a sheet-pressing member, disposed so as to press down said sheet feed roller, said sheet-pressing member formed by an elastic wire, having a cylindrical shaft portion formed by coiling the elastic wire into wire rings of generally constant diameter about a central axis so that the wire rings are brought into close contact with one another, and at least one spiral section generally in a plane perpendicular to said central axis and having an outer diameter greater than said constant diameter.
8. A printer according to claim 7, wherein said at least one spiral section is located at a middle portion of said cylindrical shaft portion.
9. A printer according to claim 7, wherein said at least one spiral section is located at a first end of said cylindrical shaft portion and an additional spiral section, generally in a plane perpendicular to said central axis and having a diameter greater than said constant diameter, is located at a second end of said cylindrical shaft portion.
10. A printer according to claim 7, wherein said printhead is of an ink jet type.
11. A printer according to claim 8, wherein said printhead is of an ink jet type.
12. A printer according to claim 9, wherein said printhead is of an ink jet type.
13. A printer comprising:
a printhead for printing characters on a sheet moving relatively to the printhead by ejecting ink drops through ink discharging orifices; and sheet-pressing members, located near said discharging orifices, for pressing on the sheet at their positions not in contact with the ink of the characters immediately after printed, said positions being spaced apart from said ink discharging orifices, said sheet-pressing members formed by an elastic wire, having a cylindrical shaft portion formed by coiling the elastic wire into wire rings of generally constant diameter about a central axis so that the wire rings are brought into close contact with one another, and at least one spiral section generally in a plane perpendicular to said central axis and having an outer diameter greater than said constant diameter.
a printhead for printing characters on a sheet moving relatively to the printhead by ejecting ink drops through ink discharging orifices; and sheet-pressing members, located near said discharging orifices, for pressing on the sheet at their positions not in contact with the ink of the characters immediately after printed, said positions being spaced apart from said ink discharging orifices, said sheet-pressing members formed by an elastic wire, having a cylindrical shaft portion formed by coiling the elastic wire into wire rings of generally constant diameter about a central axis so that the wire rings are brought into close contact with one another, and at least one spiral section generally in a plane perpendicular to said central axis and having an outer diameter greater than said constant diameter.
14. A printer according to claim 13, wherein said sheet-pressing members include at least one additional spiral section generally in a plane perpendicular to said central axis and having an outer diameter greater than said constant diameter for pressing down both sides of a region on the sheet immediately after characters are printed on the sheet.
15. A printer according to claim 13, further comprising:
a wiper for wiping ink stuck onto said ink discharging orifices while moving relatively to said ink discharging orifices, wherein said sheet-pressing members include at least one additional spiral section generally in a plane perpendicular to said central axis and having an outer diameter greater than said constant diameter for pressing down said sheet while being located at positions out of a region including said ink discharging orifices when viewed in the wiping direction of said wiper.
a wiper for wiping ink stuck onto said ink discharging orifices while moving relatively to said ink discharging orifices, wherein said sheet-pressing members include at least one additional spiral section generally in a plane perpendicular to said central axis and having an outer diameter greater than said constant diameter for pressing down said sheet while being located at positions out of a region including said ink discharging orifices when viewed in the wiping direction of said wiper.
16. A printer according to claim 14, further comprising:
a wiper for wiping ink stuck onto said ink discharging orifices while moving relatively to said ink discharging orifices, wherein said sheet-pressing members include at least one additional spiral section generally in a plane perpendicular to said central axis and having an outer diameter greater than said constant diameter for pressing down said sheet while being located at positions out of a region including said ink discharging orifices when viewed in the wiping direction of said wiper.
a wiper for wiping ink stuck onto said ink discharging orifices while moving relatively to said ink discharging orifices, wherein said sheet-pressing members include at least one additional spiral section generally in a plane perpendicular to said central axis and having an outer diameter greater than said constant diameter for pressing down said sheet while being located at positions out of a region including said ink discharging orifices when viewed in the wiping direction of said wiper.
17. A printer according to claim 10 and having a region including said ink dispensing orifices, further comprising: a wiper for wiping ink stuck onto said discharging orifices while moving relatively to said ink discharging orifices, wherein said sheet-pressing members include at least one additional spiral section generally in a plane perpendicular to said axis and having an outer diameter greater than said constant diameter for pressing down said sheet while being located at positions outside of said region including said ink discharging orifices when viewed in the wiping direction of said wiper.
18. A printer for printing on a sheet set therein, said printer comprising:
a printhead;
a guide member disposed downstream of said printhead when viewed in a sheet feeding direction and in a side where said printhead is located with respect to said sheet, said guide member defining a part of a paper transporting passage; and a spring for guiding said sheet in a direction in which said sheet is apart from said guide member, said spring formed by an elastic wire, having a cylindrical shaft portion formed by coiling the elastic wire into wire rings of generally constant diameter about a central axis so that the wire rings are brought into close contact with one another, and at least one spiral section generally in a plane perpendicular to said axis and having an outer diameter greater than said constant diameter.
a printhead;
a guide member disposed downstream of said printhead when viewed in a sheet feeding direction and in a side where said printhead is located with respect to said sheet, said guide member defining a part of a paper transporting passage; and a spring for guiding said sheet in a direction in which said sheet is apart from said guide member, said spring formed by an elastic wire, having a cylindrical shaft portion formed by coiling the elastic wire into wire rings of generally constant diameter about a central axis so that the wire rings are brought into close contact with one another, and at least one spiral section generally in a plane perpendicular to said axis and having an outer diameter greater than said constant diameter.
19. A printer comprising:
a printhead for printing characters on a sheet moving relatively to the printhead by ejecting ink drops through ink discharging orifices; and a spring, located near said discharging orifices, for guiding said sheet in a direction in which said sheet is apart from said printhead, said spring being formed by an elastic wire, having a cylindrical shaft portion formed by coiling the elastic wire into wire rings of generally constant diameter about a central axis so that the wire rings are brought into close contact with one another, and at least one spiral section generally in a plane perpendicular to said central axis and having an outer diameter greater than said constant diameter.
a printhead for printing characters on a sheet moving relatively to the printhead by ejecting ink drops through ink discharging orifices; and a spring, located near said discharging orifices, for guiding said sheet in a direction in which said sheet is apart from said printhead, said spring being formed by an elastic wire, having a cylindrical shaft portion formed by coiling the elastic wire into wire rings of generally constant diameter about a central axis so that the wire rings are brought into close contact with one another, and at least one spiral section generally in a plane perpendicular to said central axis and having an outer diameter greater than said constant diameter.
20. A printer according to claim 19, wherein said spring includes at least one additional spiral section generally in a plane perpendicular to said central axis and having an outer diameter greater than said constant diameter.
21. A printer comprising:
a printhead;
a guide member disposed downstream of said printhead when viewed in a sheet feeding direction along a paper transporting passage, said guide member defining a part of said paper transporting passage; and a spring at least partially protruded into said paper transporting passage, said spring having a cylindrical shaft portion formed by coiling an elastic wire into wire rings of generally constant diameter about a central axis so that the wire rings are brought into close contact with one another, and at least one spiral section generally in a plane perpendicular to said central axis and having an outer diameter greater than said constant diameter.
a printhead;
a guide member disposed downstream of said printhead when viewed in a sheet feeding direction along a paper transporting passage, said guide member defining a part of said paper transporting passage; and a spring at least partially protruded into said paper transporting passage, said spring having a cylindrical shaft portion formed by coiling an elastic wire into wire rings of generally constant diameter about a central axis so that the wire rings are brought into close contact with one another, and at least one spiral section generally in a plane perpendicular to said central axis and having an outer diameter greater than said constant diameter.
22. A printer according to claim 21, wherein said printhead ejects ink drops onto a sheet surface to be confronted with said guide member.
23. A paper guide for a sheet feeding mechanism, said paper guide comprising:
a guide plate having a surface along which a sheet is to be transported; and a spring supported by said guide plate, said spring having a cylindrical shaft portion formed by coiling an elastic wire into wire rings of generally constant diameter about a central axis so that the wire rings are brought into close contact with one another, and at least one spiral section generally in a plane perpendicular to said central axis and having an outer diameter greater than said constant diameter, said spiral section being partially protruded from said surface of said guide plate to be contactable with said sheet.
a guide plate having a surface along which a sheet is to be transported; and a spring supported by said guide plate, said spring having a cylindrical shaft portion formed by coiling an elastic wire into wire rings of generally constant diameter about a central axis so that the wire rings are brought into close contact with one another, and at least one spiral section generally in a plane perpendicular to said central axis and having an outer diameter greater than said constant diameter, said spiral section being partially protruded from said surface of said guide plate to be contactable with said sheet.
24. A pressing member for pressing an object being transported along a transport path, said pressing member (23; 123) including a cylindrical shaft portion (23b, 23c; 123b) formed by coiling an elastic wire into wire rings of substantially constant diameter about a central axis so that the wire rings are brought into close contact with one another, and a pressing portion (23a; 123a) formed by spirally coiling said wire to an outer diameter larger than the diameter of the shaft portion.
25. The pressing member according to claim 23, wherein said pressing portion (23a) is provided at the middle of said shaft portion (23b, 23c) in the axial direction of the latter.
26. The pressing member according to claim 24, wherein two pressing portions (123a) are provided, one at each end of said shaft portion (123b).
27. A sheet feeding mechanism for feeding a sheet along a transport path, comprising:
a sheet feed roller (22,122); and the pressing member (23; 123) as defined in any one of claims 24, 25 or 26 disposed so that said pressing portion (23a; 123a) is pressed against said sheet feed roller.
a sheet feed roller (22,122); and the pressing member (23; 123) as defined in any one of claims 24, 25 or 26 disposed so that said pressing portion (23a; 123a) is pressed against said sheet feed roller.
28. A printer for printing on a sheet set therein, said printer comprising:
a printhead (4a); and a sheet feeding mechanism as defined in calim 27, wherein the sheet feed roller (22; 122) is disposed downward of said printhead when viewed in the sheet feeding direction, for feeding a sheet printed by said printhead in said sheet feeding direction.
a printhead (4a); and a sheet feeding mechanism as defined in calim 27, wherein the sheet feed roller (22; 122) is disposed downward of said printhead when viewed in the sheet feeding direction, for feeding a sheet printed by said printhead in said sheet feeding direction.
29. A printer according to claim 28, wherein said printhead (4a) is of an ink jet type.
30. A printer comprising:
a printhead (4a) for printing characterson a sheet moving relatively to the printhead by ejecting ink drops through ink discharging orifices (42); and pressing members (24, 25) as defined in any one of claims 24, 25 or 26, wherein the pressing portions (24b, 24c, 25b, 25c) are located near to but spaced apart from said discharging orifices (42) for pressing on the sheet at positions where they do not get into contact with the ink of the just printed characters.
a printhead (4a) for printing characterson a sheet moving relatively to the printhead by ejecting ink drops through ink discharging orifices (42); and pressing members (24, 25) as defined in any one of claims 24, 25 or 26, wherein the pressing portions (24b, 24c, 25b, 25c) are located near to but spaced apart from said discharging orifices (42) for pressing on the sheet at positions where they do not get into contact with the ink of the just printed characters.
31. A printer according to claim 30 using pressing members as defined in claim 26, wherein said pressing portions (24b, 24c, 25b, 25c) are arranged for pressing down both sides of a region on the sheet immediately after characters are printed on the sheet.
32. A printer according to claim 30 or 31 using pressing members as defined in claim 26, further comprising:
a wiper (4c) for wiping ink stuck onto said ink discharging orifices while moving relatively to said ink discharging orifices (42), wherein the pressing portions (24b, 24c, 25b, 25c) of said pressing members are located at positions out of a region including said ink discharging orifices when viewed in the wiping direction of said wiper.
a wiper (4c) for wiping ink stuck onto said ink discharging orifices while moving relatively to said ink discharging orifices (42), wherein the pressing portions (24b, 24c, 25b, 25c) of said pressing members are located at positions out of a region including said ink discharging orifices when viewed in the wiping direction of said wiper.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10-97761 | 1998-04-09 | ||
| JP9776198 | 1998-04-09 | ||
| JP12377198A JP3653982B2 (en) | 1998-05-06 | 1998-05-06 | Inkjet printer |
| JP10-123771 | 1998-05-06 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2268471A1 CA2268471A1 (en) | 1999-10-09 |
| CA2268471C true CA2268471C (en) | 2007-12-04 |
Family
ID=26438911
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002268471A Expired - Fee Related CA2268471C (en) | 1998-04-09 | 1999-04-08 | Sheet-pressing member for sheet feeding mechanism |
Country Status (7)
| Country | Link |
|---|---|
| US (1) | US6299367B1 (en) |
| EP (1) | EP0949082B1 (en) |
| KR (1) | KR100476830B1 (en) |
| CN (1) | CN1205049C (en) |
| CA (1) | CA2268471C (en) |
| DE (1) | DE69902710T2 (en) |
| HK (1) | HK1023315A1 (en) |
Families Citing this family (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6547464B1 (en) * | 1999-12-01 | 2003-04-15 | Diebòld, Incorporated | Automated transaction machine printer |
| JP2005041202A (en) | 2003-07-24 | 2005-02-17 | Heidelberger Druckmas Ag | Apparatus for transferring sheet within printing machine |
| JP2005247546A (en) * | 2004-03-05 | 2005-09-15 | Brother Ind Ltd | Eject roller, transporting device, and ink jet recording device |
| US7309357B2 (en) * | 2004-12-30 | 2007-12-18 | Infinesse, Corporation | Prosthetic spinal discs |
| JP4743428B2 (en) * | 2006-08-03 | 2011-08-10 | セイコーエプソン株式会社 | Recording device |
| CN101312477B (en) * | 2007-05-25 | 2010-06-02 | 东友科技股份有限公司 | Automatic paper feeding apparatus and transaction machine suitable for the same |
| DE102007043904A1 (en) * | 2007-09-14 | 2009-03-19 | Osram Gesellschaft mit beschränkter Haftung | Luminous device |
| US20090157185A1 (en) * | 2007-12-18 | 2009-06-18 | Chong Chol Kim | Prosthetic Monolithic Spinal Discs and Method of Customizing and Constructing Discs |
| JP5444621B2 (en) * | 2008-02-26 | 2014-03-19 | 株式会社リコー | Stencil printing machine |
| JP6383196B2 (en) * | 2014-07-02 | 2018-08-29 | グラフテック株式会社 | Cutting plotter |
| JP6520528B2 (en) * | 2015-07-29 | 2019-05-29 | セイコーエプソン株式会社 | Printing device |
| CN108001050B (en) * | 2016-10-28 | 2020-03-13 | 惠普发展公司有限责任合伙企业 | Adjusting print media acquisition |
| JP6874703B2 (en) * | 2018-01-31 | 2021-05-19 | ブラザー工業株式会社 | Sheet transfer device |
| JP7267774B2 (en) * | 2019-02-28 | 2023-05-02 | キヤノン株式会社 | image forming device |
Family Cites Families (16)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US274715A (en) * | 1883-03-27 | buckley | ||
| US653155A (en) * | 1900-03-26 | 1900-07-03 | Marshall Tilden | Coil-spring. |
| US1462925A (en) * | 1921-12-12 | 1923-07-24 | Wilburger William | Spring binder post |
| US1963053A (en) * | 1933-08-14 | 1934-06-12 | Powers Spring Corp | Wire spring |
| US2852801A (en) * | 1956-08-08 | 1958-09-23 | Christian F Kleinknecht | Door stop |
| DE2506420C3 (en) * | 1975-02-15 | 1982-03-11 | Gebrüder Ahle, 5253 Lindlar | Non-cylindrical, coiled compression spring made of wire with a circular cross-section, in particular for use in motor vehicles |
| JP2643963B2 (en) | 1987-12-29 | 1997-08-25 | キヤノン株式会社 | Printer recording member transporter |
| JP2821747B2 (en) * | 1988-08-01 | 1998-11-05 | キヤノン株式会社 | Inkjet printer |
| EP0785081B1 (en) | 1989-09-18 | 2002-12-04 | Canon Kabushiki Kaisha | An ink jet recording apparatus |
| JPH06255119A (en) | 1993-03-09 | 1994-09-13 | Canon Inc | Ink jet recording apparatus |
| JP3320149B2 (en) * | 1993-06-21 | 2002-09-03 | 株式会社東芝 | Paper ejection device |
| JPH07101588A (en) | 1993-10-01 | 1995-04-18 | Canon Inc | Recording device |
| GB2285777A (en) | 1994-01-25 | 1995-07-26 | Bride David James Mc | Spring wheel |
| GB2290262B (en) * | 1994-02-10 | 1996-09-04 | Seiko Epson Corp | Ink jet printer |
| JPH08133545A (en) * | 1994-11-14 | 1996-05-28 | Ricoh Co Ltd | Paper feeding roller |
| US5868383A (en) * | 1997-03-27 | 1999-02-09 | L&P Property Management Company | Multiple rate coil spring assembly |
-
1999
- 1999-04-08 EP EP99106928A patent/EP0949082B1/en not_active Expired - Lifetime
- 1999-04-08 DE DE69902710T patent/DE69902710T2/en not_active Expired - Lifetime
- 1999-04-08 CA CA002268471A patent/CA2268471C/en not_active Expired - Fee Related
- 1999-04-08 US US09/288,170 patent/US6299367B1/en not_active Expired - Fee Related
- 1999-04-09 CN CNB99106058XA patent/CN1205049C/en not_active Expired - Fee Related
- 1999-04-09 KR KR10-1999-0012444A patent/KR100476830B1/en not_active IP Right Cessation
-
2000
- 2000-04-27 HK HK00102550A patent/HK1023315A1/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| CN1205049C (en) | 2005-06-08 |
| EP0949082A1 (en) | 1999-10-13 |
| EP0949082B1 (en) | 2002-09-04 |
| HK1023315A1 (en) | 2000-09-08 |
| CA2268471A1 (en) | 1999-10-09 |
| US6299367B1 (en) | 2001-10-09 |
| KR19990083066A (en) | 1999-11-25 |
| DE69902710D1 (en) | 2002-10-10 |
| KR100476830B1 (en) | 2005-03-18 |
| DE69902710T2 (en) | 2003-08-07 |
| CN1235093A (en) | 1999-11-17 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CA2268471C (en) | Sheet-pressing member for sheet feeding mechanism | |
| US5564847A (en) | Media handling in an ink-jet printer having guide ribs | |
| EP1693219B1 (en) | Image forming apparatus | |
| US5419644A (en) | Print medium handling system including cockle springs to control pen-to-print medium spacing during printing | |
| US5805176A (en) | Ink jet printer and device for insuring proper printing | |
| JPH0796646A (en) | Computer-driven printer and carriage support device and printing medium travel device for the printer | |
| US6089773A (en) | Print media feed system for an ink jet printer | |
| US6666536B2 (en) | Ink jet device with movable platen | |
| CN1657300B (en) | Printing device | |
| US20010010775A1 (en) | Platen and printing apparatus | |
| US6394672B1 (en) | Imaging apparatus having a biased platen | |
| EP0729842B1 (en) | Media handling in an ink-jet printer | |
| US6979080B2 (en) | Printer having improved recording medium feeding mechanism | |
| US6890114B2 (en) | Recording apparatus | |
| JP3922336B2 (en) | Flap holding member and recording apparatus provided with the member | |
| JP3812643B2 (en) | Conveyor driven roller mounting device | |
| JP3653982B2 (en) | Inkjet printer | |
| GB2290262A (en) | Paper handling in ink jet printer. | |
| JPH11349178A (en) | Paper restraint member and paper feeding mechanism using the member and printer using it | |
| JP2012046312A (en) | Recording apparatus | |
| US20080251985A1 (en) | Driven roller, transport roller device, and liquid ejecting apparatus | |
| KR970006746Y1 (en) | Sheet bail apparatus | |
| JPS6262782A (en) | Sheet conveyor for printer | |
| JP2746589B2 (en) | Printer ejection device | |
| JPH08169616A (en) | Storing device for ink jut printer discharge recording sheet |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKLA | Lapsed |
Effective date: 20130408 |