US3900192A

US3900192A - Sheet feeding apparatus

Info

Publication number: US3900192A
Application number: US428483A
Authority: US
Inventors: David K Gibson
Original assignee: International Business Machines Corp
Current assignee: International Business Machines Corp
Priority date: 1973-12-26
Filing date: 1973-12-26
Publication date: 1975-08-19
Anticipated expiration: 1992-08-19
Also published as: DE2460318C3; FR2256095B1; FR2256095A1; GB1474940A; JPS5317905B2; CA1017372A; IT1022972B; DE2460318B2; GB1474939A; JPS5099339A; JPS5175528A; DE2460318A1; JPS5317904B2

Abstract

A storage bin, which is to receive sheets on which duplexed images are to be formed by a photocopy machine after a first image is formed thereon, has its rear wall at an oblique angle to the path along which the sheet is traveling from the reproduction portion of the photocopy machine. This causes each of the sheets to be stored with its side, which is to engage a vertically disposed aligner as it passes through the photocopy machine prior to the reproduction portion, at an angle to the aligner, which has a U-shaped cross section, so that the leading corner of the sheet on the side that engages the aligner will pass the upper edge of the aligner before the aligner engages the side of the sheet. A pivotally mounted wheel receives energy from the sheet as the sheet enters the storage bin to prevent bounce back of the sheet when its edge abuts the rear wall of the storage bin so that the edge of the sheet remains against the rear wall. To insure that the sheet, irrespective of its width, arrives at a gate in its path to the reproduction portion of the photocopy machine within a predetermined time period upon its advance from the storage bin, the feed cycle of the sheet from the storage bin is divided into first and second portions. During the first portion, the sheet is fed to a predetermined position. The second portion begins a fixed period of time after the start of the feed cycle to feed the sheet from this predetermined position so that the sheet arrives at the gate within the predetermined time period.

Description

United States Patent [191 Gibson [4 1 Aug. 19, 1975 [73] Assignee: International Business Machines Corporation, Armonk, NY.

22 Filed: Dec. 26, 1973 [21 Appl. No.: 428,483

[75] Inventor:

[52] US. Cl. 271/3.1; 271/110; 271/116; 271/121; 271/220 [51] Int. Cl. 8651-1 3/06; B6511 31/26 [58] Field of Search 271/207224, 271/184, 3.1,109-1l4,116,121,124,125, 167, 4, DIG. 9

[56] References Cited UNITED STATES PATENTS 650,410 5/1900 Morin 271/121 1,086,353 2/1914 Dick 271/220 1,928,923 10/1933 Anderson 271/221 X 2,133,260 10/1938 Wolff .4 271/216 X 3,100,] 13 8/1963 Bennett et a1. 271/184 3,502,325 3/1970 Greco et a1. 271/116 X 3,612,511 10/1971 Godlewski 271/3.1 3,645,615 2/1972 Spear 271/3.1 X 3,814,415 6/1974 Hunter et a1 271/214 X Primary E.mminer--Evon C. Blunk Assistant Examiner-Bruce H. Stoner, Jr. Attorney, Agent, or FirmFrank C. Leach, .lr.

[5 7 ABSTRACT A storage bin, which is to receive sheets on which duplexed images are to be formed by a photocopy machine after a first image is formed thereon, has its rear wall at an oblique angle to the path along which the sheet is traveling from the reproduction portion of the photocopy machine. This causes each of the sheets to be stored with its side, which is to engage a vertically disposed aligner as it passes through the photocopy machine prior to the reproduction portion, at an angle to the aligner, which has a U-shaped cross section, so that the leading corner of the sheet on the side that engages the aligner will pass the upper edge of the aligner before the aligner engages the side of the sheet. A pivotally mounted wheel receives energy from the sheet as the sheet enters the storage bin to prevent bounce back of the sheet when its edge abuts the rear wall of the storage bin so that the edge of the sheet remains against the rear wall. To insure that the sheet, irrespective of its width, arrives at a gate in its path to the reproduction portion of the photocopy machine within a predetermined time period upon its advance from the storage bin, the feed cycle of the sheet from the storage bin is divided into first and second portions. During the first portion, the sheet is fed to a predetermined position. The second portion begins a fixed period of time after the start of the feed cycle to feed the sheet from this predetermined position so that the sheet arrives at the gate within the predetermined time period.

14 Claims, 6 Drawing Figures 3,900,192 sum 1 BF 3 PATENTED AUG] suns DRIVER 2m 2 BF SOLENOID FIG. 6

FIG. 4

PATENTEBAUG-I 91975 3, 900. l 92 sum 3 o 3 SHEET FEEDING APPARATUS In forming images on both sides ofasheet in a photocopy machine. it is necessary to pass the sheet through the photocopy machine to obtain an image on one side thereof and then to store the sheet. After the document, which produced the image on the one side of the sheet. has been replaced by the newldocument, which is to produce the duplexed image, the sheet can then be returned through the photocopy machine to have the duplexed image on its reverse side,

When a sheet passes through the photocopy machine to have an image formed thereon, it is necessary for the sheet to follow a predetermined path. Thus, the sheet must be aligned along one side to insure that the sheet moves along the predetermined path as the various steps of electrostatic photocopying occur. One means for aligningthe sheet is to use a U-shaped aligner to cause one side of the sheet to be. aligned against the base, which defines a vertical edge, of the aligner.

As a result of this alignment of' the sheet by the aligner, the sheet will continue in the predetermined path through the machine. Thus, when a sheet, which isto have a duplexed image formed thereon, is directed to the storage bin, it still will be moving along its predetermined path. Therefore, the possibility exists that the sheet could be so disposed within the storage bin that it would engage the end of the aligner during its return along the predetermined path for duplexing to cause jamming of the machine. 4 L

The present invention"satisfactorilysolves this problem by providing an arrangement in whichthe sheet is stored within the bin at an oblique angle to the'predetermined path which it is to followwhen it again passes through the photocopy machine to have the duplexed image formed on the reverse side thereof. The present invention controls this angle so that the sheet is removed from the storage bin at the desired angle.

In the feeding of sheets through the photocopy machine. each of the sheets must arrive at a gate,'which stops the sheet before it is fed to the reproduction portion of the photocopy machine at a desired time, within a predetermined time period. If the sheet does not arrive at the gate "within the predetermined time, then logic circuitry stops the photocopy machine to prevent jamming of the sheets in the feed path.

One prior way of insuring that each sheet, which is to have a duplexed image, arrives at the gate within the predetermined time period has been to use'sheets of a single width and dispose the sheet feed mechanism adjacent to the sheets within the storage bin. However, this has the disadvantage of limiting the size of the sheets, which are to have the duplexed images on the reverse sides, to a single width at any one time. Furthermore, this arrangement requires the user toadjust the storage bin size whenever the width of the sheets is to be different than those previously utilized.

The present invention overcomes the foregoing problems' through utilizing a sheet feed apparatusin which each sheet is initially advanced from the storage bin to a first position during afirst portion of'a feed cycle and then advanced therefrom toward the gate during a second portion of the feed cycle. The second "portion of the feed cycle for the sheet is initiated'a fixed predetermined time after the start of the-sheet feed cycle. This fixed predetermined time exceeds the time it takes to dispose the sheet at the first position from any'initial' position within thestorage' bin to thereby insure that the time period to advance the sheettoward the gate can be controlled. Thus, even with the sheets having various widths, each arrives at the gate within the pre-. determined time period when using the arrangement of the present invention. n

It should be understood that the sheet is not advanced to the gate. from the storage bin during the single feed cycle. However, by insuring that the sheet beings from a certain position at the start of the second portion of the feed cycle of the sheet from the storage bin,.the sheet is disposed in the: path in the proper location relative to the gate so that it arrives at the gate within the predetermined time: period. 7

Furthermore, the sheet feed apparatus of the present invention overcome s any problem created by shingling wherein more than one sheet is acidentally fed from the sheet stack within the storage: bin. When this occurs while using the arrangement of the present invention, each sheet is still fed so as to arrive at the gate within the predetermined time period. Thus, the sheet feed apparatus of the present invention insures that each sheet, which is to have a duplexed imaged on its reverse side, arrives at the gate within the predetermined time period. t V t An object of this invention is. to provide a sheet feed apparatus that feeds a sheet from a storage bin or the like to a predetermined position within a predetermined time interval irrespective of the location of the sheet within the storage bin.

Another object "of this invention is to provide an arangement for disposing a sheet at an oblique angle to its entering path in a storage bin.

A further object of this invention is to control the position of a sheet within astorage bin to which it is advanced.

The foregoing and other objects, features, and advantages of the invention will be more apparent from the following more particular description of a preferred embodiment of the invention as illustrated in the accompanying drawings.

In the drawings:

FIG. 1 is a schematic top plan view of the sheet feed apparatus of the present invention including the storage bin.

FIG. 2 is a schematic side elevational view of the apparatus of FIG. 1 anda portion of the photocopy machine with which the apparatus is used.

FIG. 3 is a schematic view showing the path of a sheet through the photocopy machine.

FIG. 4 is a fragmentary schematic front elevational" view of a portion of the appratus shown in FIG. 2 for aligning the sheet.

' FIG. 5 is a top plan view ofa portion of the sheet feed apparatus for feeding the sheets.

FIG. 6 is a block diagram'of an arrangement for controlling the sheet feed apparatus of the present invention.

Referring to the drawings and particularly FIG. I, there is shown a storage bin 10 of a photocopy machine 11. The storage bin 10, which is supported on main frame of the photocopy machine 11, stores sheets 12, which have been passed through the photocopy machine ll to have an image formed on one side thereof. As each of the sheets 12 enters the storage bin 10, it has the image on its top surface.

The-storage bin 10 includes a bottom wall 14, substantially

parallel side walls

15 and 16, and a rear wall 17. As shown in FIG. 2, the bottom wall 14 is disposed at an angle to the horizon to aid the sheet 12 in advancing through the storage bin toward the rear wall 17.

The rear wall 17 is disposed at an angle other than 90 to each of the side walls and 16, which are parallel to the path of the sheet 12 as it enters the storage bin 10. Thus, the rear wall 17, which has the sheet 12 abut thereaginst, is at an oblique angle to the path through which the sheet 12 advances through the photocopy machine 11 after having been aligned by a U- shaped aligner 18 (see FIG. 4). Thus, the sheet 12 is advanced into the storage bin 10, its side edges 19 and 20 are substantially parallel to the

side walls

15 and 16, respectively.

Therefore, when the sheet 12 has its edge 21, which is the leading edge of the sheet 12 during its entry into the storage bin 10, abut the rear wall 17, it rotates relative to the rear wall 17. Thus, when the sheet 12 stops, the sheet 12 has its edge 22, which becomes the leading edge when the sheet 12 is to be advanced from the storage bin 10 to the photocopy machine 11 for having the duplexed image formed thereon, at an angle to the path through the photocopy machine 11.

As the sheet 12 is advanced into the storage bin 10, it moves underneath a freely rotatable wheel 23. The wheel 23 is rotatably mounted on the end of an arm 24 (see FIG. 2), which is pivotally mounted on a switch 25. The switch 25 is supported from a deflector 26, which aids in directing the sheet 12 into the storage bin 10 beneath the wheel 23. The deflector 26 is supported at each of its ends by a downwardly projecting portion 27, which is secured to an upstanding portion 28 on each of the

side walls

15 and 16 of the storage bin 10.

When the storage bin 10 is empty, a switch arm 29 of the switch 25 has its lower end disposed within a slot 30 in the bottom wall 14 of the storage bin 10. As a result, the switch 25 presents a signal to the logic of the photocopy machine 11 to indicate that the storage bin 10 is empty. As soon as a first of the sheets 12 advances into the storage bin 10, the switch arm 29 of the switch 25 moves upwardly enough to cause the switch 25 to provide a signal to indicate that the storage bin 10 now has at least one of the sheet 12 therein.

As the sheet 12 is advanced into the storage bin 10, its movement to the left (as viewed in FIGS. 1 and 2) causes clockwise (as viewed in FIG. 2) rotation of the wheel 23. Thus, the wheel 23 becomes an inertia wheel and is still coasting when the edge 21 of the sheet 12 strikes the rear wall 17 of the storage bin 10.

The energy from the rotation of the wheel 23 is transferred to the sheet 12 due to the slight friction between the wheel 23 and the sheet 12 to hold the edge 21 of the sheet 12 against the rear wall 17 of the storage bin 10. This prevents bounce of the sheet 12 away from the rear wall 17 of the storage bin 10 and insures that the edge 22 of the sheet 12 is at an angle other than 90 to the path along which the sheet 12 is to be moved for return to the reproduction portion of the photocopy machine 11 when the duplexed image is to be formed on the sheet 12.

The proper bounce restraint of the wheel 23 is obtained through controlling the friction between the wheel 23 and the sheet 12, the weight of the wheel 23, and the inertia of the wheel 23. This allows the wheel 23 to prevent the sheet 12 from moving away from the rear wall 17 of the storage bin 10 after the edge 21 of the sheet 12 strikes the rear wall 17.

The material of the wheel 23 is selected so that the desired characteristic of preventing bounce of the sheet 12 away from the rear wall 17 of the storage bin 10 is obtained. The material is selected so that friction between the wheel 23 and the sheet 12 is not too high since a high friction therebetween would result in the wheel 23 reversing direction when the sheet 12 attemped to bounce back from the rear wall 17. The weight of the wheel 23 is controlled to insure that it is easy to spin or rotate the wheel 23 and to keep it spinning or rotating. The inertia of the wheel 23 is maintained relatively low since this also can effect the starting of the rotation of the wheel 23. The relatively low inertia is obtained by using a relatively small radius for the wheel 23. To obtain the low weight of the wheel 23 while still having the fairly low coefficient of friction, most thermoplastic materials can be employed. The wheel 23 is preferably formed of Nylatron GS although Delrin or nylon are other suitable examples.

The sheet 12 is directed into the storage bin 10 after having an image formed on one side thereof by a pivotally mounted snout 40 (see FIG. 2). The snout 40 is pivotally mounted on brackets, which are f xed to the main frame of the photocopy machine 11. The snout 40 has a pair of driven rollers 41 with each of the driven rollers 41 cooperating with an idler roller 42 between which the sheet 12 is advanced.

The driven rollers 41 on the snout 40 are continuously driven through a chain whenever the photocopy machine 11 is turned on. The snout 40 pivots about the axis of the drive shaft to which the chain is connected.

The driven rollers 41 provide momentum to the sheet 12 so that it will strike the rear wall 17 of the storage bin 10. The snout 40 is pivotal between a position (solid line position of FIG. 2) in which each of the sheets 12 is directed into the storage bin 10 and to a position (phantom line position of FIG. 2) in which the sheets 12 are directed to a storage tray (not shown) exderneath the wheel 23 and against the wall 17 of the I I storage bin 10. The deflector 26 aids in directing the sheet 12 into the storage bin 10 beneath the wheel 23.

When the sheet 12 enters the storage bin 10, the uppermost left corner (as viewed in FIG. 1) of the sheet 12 engages the rear wall 17 first because of the angle of the rear wall 17 and then the sheet 12 pivots about the corner of the sheet 12 until the entire leading edge 21 of the sheet 12 is against the rear wall 17 of the storage bin 10. The momentum from the drive rollers 41 on the snout 40 are sufficient to cause this pivoting.

The wheel 23 prevents the bounce back of the sheet 12 when the corner of the sheet 12 engages the rear wall 17 of the storage bin 10. The wheel 23 also prevents bounce back when the entire edge'21 of the sheet 12 is engaging the rear wall 17 of the storage bin 10to insure that the sheet 12 does not have its edge 21 move away from the rear wall 17 of the storage bin 10.

After the sheets 12 have been formed in a stack in the storage bin 10, it is necessary to advance each of the sheets 12 separately therefrom for return to the reproduction portion of the photocopy machine 11 to produce the duplexed image on each of the sheets 12. Accordingly, two picker rolls 50 are supported above the storage bin 10. Each of the picker rolls 50 is rotatably mounted on a truck 51 (see FIG. 5), which is pivotally mounted to cause the picker roll 50 thereon to be moved out of engagement with the storage bin when the sheets 12 are to be supplied thereto. When the sheets 12 are to be advanced from the storage bin 10 for return to the reproduction portion of the photocopy machine 11, the trucks 51 are pivoted so that the picker rolls 50 are moved into engagement with the top sheet 12 on the stack of the sheets 12 within the storage bin 10.

The picker rolls 50 are rotated counterclockwise (as viewed in FIG. 2) to advance each of the sheets 12 out of the storage bin 10 and between a pair of

guides

52 and 53 between which the sheets 12 move. Each of the picker rolls 50 has its axis of rotation perpendicular to the

side walls

15 and 16 so that the sheets 12 are advanced in the direction of the predetermined path that they are to follow through the photocopy machine 11. This insures that the sheets 12 are advanced from the storage bin with each of the sheet 12 skewed relative to the predetermined path.

Each of the picker rolls 50 is driven from a shaft 54 (see FIG. 5). which has the trucks 51 pivotally mounted thereon through bearings in the truck 51 having the shaft 54 extend therethrough. Thus, by each of the trucks 51 being pivotally mounted separately, any variation in the level of the stack of the sheets 12 will not prevent both of the picker rolls 50 from engaging the stack of the sheets 12.

The shaft 54 is connected to each of the picker rolls 50 by a timing belt 55 extending between a pulley 56 on the shaft 54 and a pulley 57 on a shaft 58 of the picker roll 50. The shaft 54 is mounted in a bearing 59 on a support 60, which is fixed to the main frame of the photocopy machine 11.

The trucks 51 of the picker rolls 50 are moved into or out of engagement with the top of the stack of the sheets 12 in the storage bin 10 by an arm 61 being moved between two positions through a suitable driving arrangement including a two position clutch (not shown). The picker rolls 50 are in engagement with the sheets 12 when the sheets 12 are to be fed out of the storage bin 10, and the picker rolls 50 are elevated when the sheets 12 are fed into the storage bin 10.

When the picker rolls 50 are elevated, fingers 61 on the arm 61 hold them in this position by supporting the trucks 51. However, when the picker rolls 50 are in engagement with the sheets 12, the picker rolls 50 are supported solely by the sheets 12 as the arm 61 is disposed in a position in which the fingers 61' do not support the trucks 51.

To advance the sheet 12 from the storage bin 10, the picker rolls 50 must be rotated through rotation of the shaft 54. A timing wheel (not shown) is utilized to control when a sheet feed cycle begins through enabling the shaft 54 to be connected by a spring clutch and gearing arrangement to a main power shaft, which is continuously driven whenever the photocopy machine 11 is turned on.

At the start of the feed cycle, the timing wheel causes a pulse to be supplied to an input line 62 of a latch 63 (see FIG. 6). The latch is a bistable flip-flop with an overriding reset.

As a result of the timer wheel causing the input line 62 of the latch 63 to receive an input pulse, the latch 63 is set to produce a positive pulse on its output line 64, which is connected to an OR gate 65. The pulse is supplied from the OR gate 65 through a driver 66, which amplifies the signal, to energize a solenoid 67. The energization of the solenoid 67 moves a pivotally mounted arm (not shown), which is resiliently biased into engagement with a ratchet wheel sleeve (not shown), out of engagement with the ratchet wheel sleeve so that the spring clutch can connect the shaft 54 to the continuously driven main power shaft through the gearing arrangement.

As the sheet 12 is advanced from the storage bin 10 by the picker rolls 50, the edge 22 of the sheet 12 engages a pivotally mounted switch lever 69 (see FIG. 2). When the switch lever 69 is moved by the sheet 12 advancing to this position, the switch lever 69 causes its switch to close to supply a signal to input line 70 (see FIG. 6) of the latch 63 of the logic of the photocopy machine 11. The signal to the input line 70 of the latch 63 resets the flip flop so that its output on the output line 64 falls whereby the solenoid 67 is deenergized. As a result, the pivotally mounted arm, which cooperates with the solenoid 67, is returned by its spring into engagement with the ratchet wheel sleeve to inactivate the spring clutch whereby the shaft 54 is disconnected from the continuously rotating main power shaft to inactivate the picker rolls 50.

A separator roll 71 (see FIGS. 1 and 2), which is disposed downstream from the switch lever 69, is driven whenever the picker rolls 50 .are driven. The separator roll 71 has its shaft connected through a gearing arrangement with the gearing arrangement, which drives the shaft 54 from the main power shaft when it is connected thereto by the spring clutch. The separator roll 71 cooperates with a curved surface 72 of a restraint pad 73, which is fixed, to advance each of the sheets 12 separately therebetween.

Thus, when the switch lever 69 is moved by the sheet 12, both the picker rolls 50 and the separator roll 71 are stopped to prevent further advance of the sheet 12 at this time. As a result, the sheet 12 is advanced to a predetermined position and held there until a predetermined period of time, which is determined by the rotation of the timing wheel, has elapsed from the start of the sheet feed cycle.

After the sheet 12 is in the predetermined position to which it is advanced from the storage bin 10, the timing wheel causes a pulse to be supplied to an input line 75 of a latch 76 of the logic of the photocopy machine 11 to set the latch 76, which is a bistable flip flop, in a state in which a positive pulse appears on its output line 77. The positive pulse on the output line 77 is supplied through the OR gate 65 and the driver 66 to energize the solenoid 67. When this occurs, the picker rolls 50 and the separator roll 71 again are activated to advance the sheet 12 between the

guides

52 and 53.

It should be understood that the separator roll 71 is rotating faster than the picker rolls 50 so that the sheet 12 increases in linear speed when it is driven by the separator roll 71. As a result, the picker rolls 50 overrun due to a one-way clutch, which is separate from the spring clutch, whereby the picker rolls 50 rotate at the same speed as the separator roll 71 rather than the slower speed at which the shafts 58 are rotating.

As the sheet 12 moves along the

guides

52 and 53, it passes between two sets of continuously rotating pinch rolls with each set comprising an upper pinch roll 78 (see FIGS. 1 and 2) and a lower pinch roll 79 (see FIG. 2). Since the pinch rolls 78 and 79 are rotating faster than the separator roll 71, the linear speed of the sheet 12 advances when the driving of the sheet 12 by the pinch rolls 78 and 79 begins. As a result, the separator roll 71 overruns relative to its shaft through a one-way clutch so that the separator roll 71 is rotating at the same speed as the sheet 12 is being advanced by the pinch rolls 78 and 79. Of course, the speed of rotation of the picker rolls 50 increases too.

The timing wheel causes a pulse to be supplied to an input line 80 of the latch 76 a predetermined period of time after the pulse was supplied to the input line 75 of the latch 76. This resets the latch 76 to cause the voltage on the output line 77 of the latch 76 to drop whereby the solenoid 67 is again deenergized to inactivate the picker rolls 50 and the separator roll 71. The time period between changing the states of the latch 76 on the output line 77 is sufficient to insure that the sheet 12 has been advanced sufficiently by the picker rolls 50 and the separator roll 71 so that the pinch rolls 78 and 79 are driving the sheet 12.

After the pinch rolls 78 and 79 start to drive the sheet 12, it moves around the curved portions of the exit guides 52 and 53. Then, the sheet 12 moves between a guide 81 and a vertical extension of the guide 53. The sheet 12 is advanced through the

guides

81 and 53 by a feed roll 82 cooperating with a pressure roll 83. The feed roll 82 is driven whenever the pinch rolls 78 and 79 are activated.

After leaving the

rolls

82 and 83, the sheet 12 is driven by feed rolls 84, which are canted to the path of travel, as shown in FIG. 4, with each of the rolls 84 acting against a pressure roll 85. A second set of feed rolls 86, which are canted as shown in FIG. 4, engages pressure rolls 87 to drive the sheet 12.

As the sheet 12 is advanced by the feed rolls 84 and 86 between

guides

88 and 89, which are vertically aligned with the vertical extension of the guide 53 and the guide 81, respectively, the sheet 12 passes through the U-shaped aligner 18 (see FIG. 4), which is disposed between the

guides

88 and 89. It is the top edge of the aligner 18, are prevously mentioned, that it is desired for the leading edge 22 of the sheet 12 to not engage as it moves along its predetermined path through the photocopy machine 11. The aligner 18, which is not shown in FIG. 2 for clarity purposes, removes the skew, which is produced by the rear wall 17 of the storage bin 18, of the sheet 12.

The sheet 12 trips a switch 90 as it moves through the aligner 18 so that the logic of the photocopy machine 11 can determine that the sheet 12 is in a desired position to reach a gate 91 (see FlG. 3), which is defined by pairs of cooperating rolls having unique peripheral surfaces as more particularly shown and described in the copending patent application of Gary D. Anderson et al. for Sheet Feed Apparatus," Ser. No. 308,640, filed Nov. 2l, 1972, now abandoned, and assigned to the same assignee as the assignee of this application, within a predetermined period of time.

A feed roll 92 (see FIG. 2), which cooperates with a pressure roll 93, advances the sheet 12 from the aligner 18 in the

guides

88 and 89 to guides (not shown) with which the rolls of the gate 91 cooperate.

Thereafter, the sheet 12 is passed over a photoconductor drum 96 to have an image formed thereon in the well-known electrostatic manner. Then, after the sheet 12 is removed from the drum 96, it is advanced by a vacuum belt 97 to a fuser 98 at which the image is fused on the sheet 12 to form the duplexed image thereon.

Then, the sheet 12 is advanced by feed rolls and guides to the exit tray on the exterior of the photocopy machine 11 to enable the user to have access thereto. The snout is positioned to direct the sheet 12 in this direction.

Upon the inactivation of the picker rolls and the separator roll 71, the timing wheel causes a pulse to again be supplied to the input line 62 (see FIG. 6) of the latch 63 a predetermined period of time after causing the supply of the pulse to the input line 80 of the latch 76 to reset the latch 76. Thus, the timing wheel controls the length of each of the sheet feed cycles. By supplying another pulse to the input line 62 of the latch 63 to set the latch 63, the picker rolls 50 and the separator roll 71 are again activated so that another feed cycle occurs. This continues until all of the sheets 12 in the storage bin 10 have been removed therefrom.

If any of the sheets 12 are of different widths or should inadvertently fail to align against the rear wall 17, each of the sheets 12 can still be advanced to a desired position in the predetermined path within the predetermined period of time. This is because each of the sheets 12 is advanced to the predetermined position at which the switch lever (see FIG. 2) is moved. Since the second portion of the feed cycle does not begin until a predetermined period of time after start of the feed cycle, it is only necessary for the sheet 12 to arrive at the predetermined position before the second portion of the feed cycle is to start. By always starting the second portion of the feed cycle at a particular time period, the edge 22 (see FIG. 1) of the sheet 12 will always be starting at a known time from a fixed position to reach the gate 91 (see FIG. 3) within the desired time.

If more than one of the sheets 12 should be shingled from the stack in the storage bin 10 at the same time, only one of the sheets 12 can be fed between the separator roll 71 and the restrain pad 73. This is because the coefficent of friction of the restraint pad 73 is higher than the coefficient of friction between two of the sheets 12 and the separator roll 71 has a higher coefficient of friction than the restraint pad 73. Thus, the separator roll 71 can feed one of the sheets 12 past the restraint pad 73 while the other of the sheets 12 will not be fed because of the low coefficient of friction between the two sheets 12.

If this occurs, the switch lever 69 remains in the position in which it supplies a signal to the input line (see FIG. 6) of the latch 63 of the logic of the photocopy machine 11. As a result, since the latch 63 is a bistable flip flop with an overriding reset, supply of the positive signal from the timing sheel to the input line 62 of the latch 63 at the start of the next feed cycle cannot change the state of the latch 63 because of the overriding reset feature of the signal from the input line 70 to the latch 63. As a result, there is no activation of the picker rolls 50 or the separator roll 71 since the solenoid 67 cannot be energized.

However, when the timing wheel causes a signal to be supplied to the input line of the latch 76 to set the latch 76, the latch 76 changes state so that the output line 77 has a positive pulse thereon to cause energization of the solenoid 67. Thus, when a predetermined period of time from the start of the feed cycle to the second portion of the feed cycle has elapsed, the picker rolls 50 and the separator roll 71 are activated through the solenoid 67 being energized. The activation of the picker rolls 50 and the separator roll 71 causes the sheet 12 to advance between the

guides

52 and 53 towards the gate 91 in the path to the reproduction portion of the photocopy machine 11. 1

Thus, by dividing the sheet feed cycle from the storage bin 10 into two segments or portions, the sheet feed apparatus of the present invention is capable of handling the sheets 12 with different widths. This also al lows feeding of only one of the sheets 12 at a time to the reproduction portion of the photocopy machine 11 even though the sheets 12 are shingled.

To insure that the stack of the sheets 12 is not inadvertently shifted in some manner by the picker rolls 50 when one of the sheets 12 is to be advanced from the storage bin 10, a strip 100 of foam is disposed on the bottom wall 14 of the storage bin 10 at its side remote from the rear wall 17. This prevents the entire stack of the sheets 12 from being moved by the picker rolls 50.

While the present invention has shown and described the wheel 23 as having the arm 24 pivotally mounted on the switch 25, it should be understood that such is not a requisite for satisfactory operation. It is only nec' essary that the arm 24 be pivotally mounted in some manner to accommodate the varying heights of the stack of the sheets 12 within the storage bin 10 without exerting an undesired drag on the sheets 12.

While the present invention has shown the wheel 23 as forming the control to prevent bounce of the sheet 12, it should be understood that any other suitable means could be employed. It is only necessary that the desired force be exerted on the sheet 12 at the desired time to prevent bounce therof.

While the switch lever 69 has been shown as being disposed before the entry of the sheet 12 between the separator roll 71 and the restraint pad 73, it should be understood that such is not a requisite for satisfactory operation of the sheet feed apparatus of the present invention. Thus, for example the switch lever 69 could be disposed to be actuated by the sheet 12 after it has passed between the separator roll 71 and the restraint pad 73. Of course, this would necessitate the pinch rolls 78 and 79 being disposed far enough from the switch lever 69 so that the sheet 12 would stop during the first portion of the feed cycle before it could be grasped by the pinch rolls 78 and 79. Thus, it is only necessary to define a position to which the sheet 12 is advanced from the storage bin 10 and then start the feed of the sheet 12 again therefrom a predetermined period of time after the feed cycle has started.

An advantage of this invention is that it prevents jamming of sheets fed through a photocopy machine to have a duplexcd image formed thereon. Another advantage of this invention is that there is no requirement for the user of the photocopy machine to adjust the size of the storage bin for various widths of sheets which are to have a duplexed image formed thereon by the photocopy machine. A further advantage of this invention is that it eliminates the problems of variations in the locations of sheet within a shortage bin. Still another advan tage of this invention is that it enables the storage of sheets of varying width without making any adjustment therefor while still having the sheets advanced from the bin to a predetermined location within a predetermined period of time.

While the invention has been particularly shown and described with reference to a preferred embodiment thereof, it will be understood by those skilled in the art that the foregoing and other changes in form and de tails may be made therein without departing from the spirit and scope of the invention.

What is claimed is:

1. A sheet feed apparatus for sequentially feeding each sheet from a stack of sheets located in a storage bin or the like to a predetermined position within a predetermined time period irrespective of the dimension of each sheet in the feed direction or its location in the feed direction within the storage bin including:

means to advance a sheet from the storage bin in the feed direction;

first activating means to activate said advancing means at the start of a sheet advance cycle if a sheet is not at a first position;

first inactivating means to inactivate said advancing means when the sheet is advanced to the first position by said advancing means, said first inactivating means preventing activation of said advancing means by said first activating means if the sheet is at the first position at the start of the sheet advance cycle;

and second activating means to activate said advancing means a constant predetermined period of time after the start of the sheet advance cycle and greater than the period of time for said advancing means to advance a sheet of minimum dimension in the feed direction to the first position from its most remote position in the storage bin to advance the sheet from the first position toward the predetermined position irrespective of whether said first activating means activated said advancing means at the start of the sheet advance cycle.

2. The apparatus according to claim 1 in which said first inactivating means includes:

means to sense when the sheet is at the first position;

and means responsive to said sensing means sensing the sheet at the first position to inactivate said advancing means.

3. The apparatus according to claim 2 in which said advancing means includes means to prevent more than one of the sheets from being advanced from the first position by said advancing means during each sheet advancing cycle, said preventing means being spaced from the storage bin in the direction in which the sheet is advanced from the storage bin by said advancing means.

4. The apparatus according to claim 3 including sec- .ond inactivating means to inactivate said advancing means a constant predetermined period of time after being activated by said second activating means, said second inactivating means being separate from said first inactivating means.

5. The apparatus according to claim 1 in which said advancing means includes means to prevent more than one of the sheets from being advanced from the first position by said advancing means during each feed cycle, said preventing means being spaced from the storage bin in the direction in which the sheet is advanced from the storage bin by said advancing means.

6. The apparatus according to claim 2 in which said advancing means includes:

first means to engage the top surface of the top sheet in the storage bin to start feed of the sheet therefrom; 5 and second means to prevent more than one of the sheets from being advanced past said second means during each sheet advance cycle. said second means of said advancing means being spaced from the storage bin in the direction in which the sheet is advanced from the storage bin by said advancing means. 7. The apparatus according to claim 6 in which: said second means of said advancing means includes:

a fixed restraint pad having a curved surface; and a separator roll engaging said curved surface of said fixed restraint pad to prevent more than one sheet from passing therebetween during any sheet advance cycle while advancing the one sheet therebetween; and said first means of said advancing means and said separator roll being driven at the same time. 8. An arrangement for controlling the position of an first means to advance the sheet into the storage bin along the predetermined path;

abutment means in the storage bin disposed at an oblique angle to the predetermined path for the sole engagement by the leading entry edge of the sheet in its travel along the predetermined path into the storage bin;

means to cooperate with each sheet as it travels through the storage bin and strikes said abutment means to control the position of the sheet relative to said abutment means so that the leading entry edge of the sheet remains against said abutment means whereby the trailing entry edge of the sheet is at an oblique angle to the predetermined path;

and second means to advance each of the sheets in the storage bin out of the storage bin in a direction away from said abutment means and substantially parallel to the predetermined path to cause each of the sheets to remain at its angled relation to the predetermined path.

9. The arrangement according to claim 8 in which said cooperating means includes means exerting a force on each sheet initially only as it strikes said abutment means.

10. The arrangement according to claim 9 in which said force exerting means includes a pivotally mounted wheel rotating in the same direction as-the direction of the sheet before the sheet strikes said abutment means.

11. The arrangement according to claim 10 including means to support said wheel for engagement by the sheet as the sheet is advanced along the predetermined path toward said abutment means to cause said wheel to receive its direction of rotation.

12. The arrangement according to claim 8 including:

first activating means to activate said second advancing means at the start of a sheet advance cycle if a sheet is not at a first position;

means to inactivate said second advancing means when the sheet is at the first position;

and second activating means to activate said second advancing means a constant predetermined period of time after the start of the sheet advance cycle to advance the sheet from the first position to a predetermined position.

13. The arrangement according to claim 12 in which said inactivating means includes:

means to sense when the sheet is at the first position;

and means responsive to said sensing means to inactivate said second advancing means.

14. The arrangement according to claim 10 including means to pivotally mount said wheel for movement into and out of engagement with the top of the sheets in the storage bin.

Claims

1. A sheet feed apparatus for sequentially feeding each sheet from a stack of sheets located in a storage bin or the like to a predetermined position within a predetermined time period irrespective of the dimension of each sheet in the feed direction or its location in the feed direction within the storage bin including: means to advance a sheet from the storage bin in the feed direction; first activating means to activate said advancing means at the start of a sheet advance cycle if a sheet is not at a first position; first inactivating means to inactivate said advancing means when the sheet is advanced to the first position by said advancing means, said first inactivating means preventing activation of said advancing means by said first activating means if the sheet is at the first position at the start of the sheet advance cycle; and second activating means to activate said advancing means a constant predetermined period of time after the start of the sheet advance cycle and greater than the period of time for said advancing means to advance a sheet of minimum dimension in the feed direction to the first position from its most remote position in the storage bin to advance the sheet from the first position toward the predetermined position irrespective of whether said first activating means activated said advancing means at the start of the sheet advance cycle.

2. The apparatus according to claim 1 in which said first inactivating means includes: means to sense when the sheet is at the first position; and means responsive to said sensing means sensing the sheet at the first position to inactivate said advancing means.

4. The apparatus according to claim 3 including second inactivating means to inactivate said advancing means a constant predetermined period of time after being activated by said second activating means, said second inactivating means being separate from said first inactivating means.

6. The apparatus according to claim 2 in which said advancing means includes: first means to engage the top surface of the top sheet in the storage bin to start feed of the sheet therefrom; and second means to prevent more than one of the sheets from being advanced past said second means during each sheet advance cycle, said second means of said advancing means being spaced from the storage bin in the direction in which the sheet is advanced from the storage bin by said advancing means.

7. The apparatus according to claim 6 in which: said second means of said advancing means includes: a fixed restraint pad having a curved surface; and a separator roll engaging said curved surface of said fixed restraint pad to prevent more than one sheet from passing therebetween during any sheet advance cycle while advancing the one sheet therebetween; and said first means of said advancing means and said separator roll being driven at the same time.

8. An arrangement for controlling the position of an edge of a sheet in a storage bin or the like relative to a predetermined path along which the sheet travels into the storage bin including: first means to advance the sheet into the storage bin along the predetermined path; abutment means in the storage bin disposed at an oblique angle to the predetermined path for the sole engagement by the leading entry edge of the sheet in its travel along the predetermined path into the storage bin; means to cooperate with each sheet as it travels through the storage bin and strikes said abutment means to control the position of the sheet relative to said abutment means so that the leading entry edge of the sheet remains against said abutment means whereby the trailing entry edge of the sheet is at an oblique angle to the predetermined path; and second means to advance each of the sheets in the storage bin out of the storage bin in a direction away from said abutment means and substantially parallel to the predetermined path to cause each of the sheets to remain at its angled relation to the predetermined path.

10. The arrangement according to claim 9 in which said force exerting means includes a pivotally mounted wheel rotating in the same direction as the direction of the sheet before the sheet strikes said abutment means.

12. The arrangement according to claim 8 including: first activating means to activate said second advancing means at the start of a sheet advance cycle if a sheet is not at a first position; means to inactivate said second aDvancing means when the sheet is at the first position; and second activating means to activate said second advancing means a constant predetermined period of time after the start of the sheet advance cycle to advance the sheet from the first position to a predetermined position.

13. The arrangement according to claim 12 in which said inactivating means includes: means to sense when the sheet is at the first position; and means responsive to said sensing means to inactivate said second advancing means.