EP0789332A2 - Device for printing a printing support standing on an edge - Google Patents

Abstract

The device includes a guide plate with an extruded area for a printing arrangement. The extruded area comprises at least an extrusion (21, 22) and the area (25, 26) of the guide plate (2) following the extrusion in a transport direction is modeled so that the print carrier (3) is exposed at this point. The printing arrangement is an ink printing arrangement with a nozzle plane (40) extending parallel to the guide plate, and the ink arrangement is positioned stationary during the printing process. A slope of the guide plate with respect to a vertical line is at most 45 degrees, and devices (1) are provided for producing a force on the print carrier for its advance in the transport direction along the guide plate.

Description

The invention relates to a device for printing a print carrier standing on an edge, in particular a letter in franking and / or addressing machines.

In devices of this type, the print carrier is guided along a printing device and the franking or address is printed in one pass.

It is common to guide the print carrier either lying flat, see for example US 5,467,709, or standing on an edge, see for example US 5,025,386, along the printing device.

In any case, it is important that the print carrier and the printing device come to a defined position in relation to one another so that the print is made at the intended location and with sufficient quality.
In the case of horizontal transport, a relatively large contact area is required in accordance with the largest print carrier format used, which in turn requires a correspondingly large footprint for the machine.
In the solution according to US Pat. No. 5,467,709, printing is carried out without contact by means of an ink print head. The letter is conveyed between a driven conveyor belt and spring-loaded pressure rollers, the letter also abutting a longitudinal guide plate. The longitudinal guide plate is provided with a recess adapted to the conveyor belt and with a rectangular recess for the ink print head, over the diagonal of which the row of nozzles of the ink print head runs. The conveyor belt, the longitudinal guide plate and the ink print head are arranged above the letter. The resilient pressure rollers and a pressure roller resiliently mounted in the printing area are arranged under the letter. The spring travel of the pressure rollers and the pressure plate corresponds to the maximum thickness of the letters, which can vary between 2 mm and 20 mm. The spring force must be sufficient for the entire weight range of the letters - approximately 20 to 1000 g - and also for the letters to lie sufficiently flat in the area of the recess for the print head. For the non-contact ink printing process, a constant, as small as possible distance between the print carrier and the ink print head must be maintained, so that on the one hand misaligned splashes have little effect and on the other hand the print carrier does not touch the nozzle surface and thus lubricants are avoided.
However, there is still the risk of smearing if the letter leaves the area of the recess and then inevitably slides along the longitudinal guide plate.
In the case of rapidly changing mixed mail, these conditions are difficult to meet.
Furthermore, a franking machine is known, compare already mentioned US Pat. No. 5,025,386, in which the letters are conveyed upright, slightly inclined, on a rotating conveyor belt. The letters rest on a guide plate in which a print window is provided. A thermal print head can be moved in height and to the side in the print window arranged with which the franking imprint is carried out on the letter. The size of the print window must be adapted to the maximum length and width of the print image. The individual letter is moved to the print window, then stopped and pressed against the guide plate or the print window by means of a pressure plate. Only then can the printing process begin.
The pressure plate is driven by a motor via gear drives and a crank joint. This is a relatively large mechanical effort and the counterpressure forces to be applied for thermal printing are also large.
After printing, the letter is released and transported on.
It is evident that only low letter throughput rates can be achieved with this intermittent operation. The effort for the thermal print head adjustment is considerable.

The purpose of the invention is to simplify the transport of letters and to improve the printing technology.

The invention has for its object to provide a device for printing a print carrier standing on an edge, which ensures a perfect print image at high throughput.

According to the invention, this object is achieved by a device having the features of claim 1.
Continuous transport and printing are possible thanks to the use of an ink printhead. Since printing is done without contact, the contact force is sufficient for a defined position of the print head due to the inclination of the guide plate and the conveyor belt. The friction on the guide plate can be kept low by a correspondingly smooth surface and / or slide rails.
The inventive design of the area of the guide plate following the printing area or the recess in the transport direction causes the printing medium to be exposed at this point.
As a result, the ink has a sufficiently long penetration time - also known as strike-off time - and thus prevents the printed image from smearing.

The fact that the area in front of the recess and the nozzle plane are staggered behind one another, and that the subsequent area is set back even further or is open, also prevents the recording medium from getting caught on one of the edges.
Specifically, the guide plate in the area after the recess can either be continued as an open recess or be set back by a depth that is greater than the largest to be expected by mechanical shaping - for example in the plastic injection molding process using the casting mold - or by removal from the contact surface for the pressure carrier Curvature of the print medium in the printed area.
In the case of the latter two variants, this is practically only a few tenths of a millimeter, but the clearance depth can be up to two millimeters in order to realize the staggered back offset.
By arranging slide rails in the transport direction on the guide plate, the contact surface for the pressure carrier can be significantly reduced and thus also the friction.
The already mentioned system-free area for the printed part of the print carrier can be easily realized in that the slide rails are further apart than the print image width and are thicker than the largest curvature of the print carrier to be expected.
The realization of the structured part of the guide plate by means of a stainless metal insert has several advantages.
This insert can then be punched and pressed out of a piece of sheet metal using a follow-on tool. Stainless metal is very easy to polish, abrasion-resistant and has good sliding properties.
The guide plate and the conveyor belt form an angle of 90 ^o . If you place the coordinates of an imaginary coordinate cross with x in the transport direction or longitudinal edge of the conveyor belt, z in the width direction of the conveyor belt and y in the vertical extension of the guide plate, it can be seen that the z and x position of the print carrier can be easily maintained.
The inclination of the guide plate is chosen over 90 ^o so that the print carrier takes a secure contact position, but the contact force is nevertheless so low that the abrasion is negligible. The skew is preferably an angle α in = 18 ^o the zx plane of the solder.

This minimizes the forces acting on the print carrier and ensures high position stability. Depending on the friction pairing, a range from greater than 90 ^o to 135 ^{o is also} possible.

If franking and address printing are to be carried out in one pass, this is possible with an ink print head, but it requires a corresponding adjustment device for the ink print head.
If an ink print head is permanently assigned to each recess or print function, then not only is the adjustment device not necessary, but it can also be printed in different colors - for example franking imprint red and address printing black.

The arrangement of the incremental encoder with the drive roller connected on a common axis and the use of a conveyor belt consisting of a toothed belt ensure an accurate detection of the transport path and an accurate slip-free movement transmission.

Fig. 1

eine perspektivische Ansicht einer erfindungsgemäßen Vorrichtung mit glatter Führungplatte,

Fig. 2

eine perspektivische Ansicht einer erfindungsgemäßen Vorrichtung mit einer Führungsplatte mit Gleitschienen,

Fig. 3

eine perspektivische Ansicht einer erfindungsgemäßen Vorrichtung mit einer Führungsplatte mit einem Einsatz;

• a) die Gesamtansicht,
• b) den Einsatz in der Pespektive,
• c) einen Längsschnitt im Druckbereich,

Fig. 4

eine perspektivische Ansicht einer erfindungsgemäßen Vorrichtung mit nach hinten offenen Ausnehmungen.

The invention is explained in more detail below using the exemplary embodiment.
Show it:

Fig. 1

2 shows a perspective view of a device according to the invention with a smooth guide plate,

Fig. 2

1 shows a perspective view of a device according to the invention with a guide plate with slide rails,

Fig. 3

a perspective view of a device according to the invention with a guide plate with an insert;

• a) the overall view,
• b) use in perspective,
• c) a longitudinal section in the printing area,

Fig. 4

a perspective view of a device according to the invention with recesses open to the rear.

To simplify the illustration and for a better understanding, the drawing is partially schematic.

1, the device according to the invention for printing a print carrier standing on an edge 31, in the further letter 3, essentially consists of a conveyor belt 1, a guide plate 2 arranged orthogonally to the transport plane and above this and an ink print head 4. A sensor 7 is used for Start of letter detection and print triggering.
The conveyor belt 1 consists of a belt 10 and two rollers 11. One of the rollers 11 is the drive roller. Both rollers 11 are preferably designed as toothed rollers in a manner not shown, and accordingly the belt 10 as toothed belt. This ensures clear power transmissions.
The drive roller 11 is fixed with an incremental encoder 5 on an axis, likewise not visible. The incremental encoder 5 is designed, for example, as a slotted disc which is illuminated by a photocell 6.
The guide plate 2 is preferably arranged at an angle α = 18 ^° to the perpendicular. Guide plate 2 and conveyor belt 1 form an angle of 90 ° with one another. The letters 3 standing on the conveyor belt 1 are inevitably in contact with the guide plate 2 due to the inclined position thereof.
When the conveyor belt 1 moves, the letters 3 slide along the fixed guide plate 2.
A first recess 21 for the ink print head 4 and a second recess 22 for the same or a further ink print head 4 are provided in the guide plate 2.
The franking imprint is made through the recess 21 and the address is printed through the recess 22.
The guide plate 2 is set back in the transport direction downstream in the area 25 or 26 behind the recesses 21 or 22 relative to the contact surface for the letter 3 so that the printed surface is certainly exposed. In this case, the offset is produced by cranking the guide plate 2.

In the device according to FIG. 2, the guide plate 2 is provided with slide rails 23, 231 parallel to the transport direction in order to improve the sliding properties. In the rear part, the guide plate 2 also has two recesses 21, 22, as in the first exemplary embodiment. The recess 21 is at the level of the to be applied Franking imprint arranged. The recess 22 is located at the address to be printed.
The ink print head 4 is arranged in the recess 21 with its nozzle surface parallel to the guide plate 2 so that the distance to the letter that is passed is approximately 1 to 2 mm. The sensor 7 for detecting the start of a letter in the guide plate 2 just before the recess 21 triggers the pressure signal in cooperation with the incremental encoder 5.
Depending on the choice, an ink print head 4 can be fixedly arranged in each recess or only one ink print head 4 can be moved from one recess into the other. On the one hand this would save the costs for a second ink print head, but on the other hand it would require a corresponding kinematic effort.
In the area 25, 26 after the recess 21, 22, the slide rails 231 are at a distance a from one another which is greater than the printed image width b. The thickness d of the slide rails 231 is greater than the largest curvature w of the letter 3 to be expected. With a distance a> 25 mm and a thickness d = 2 mm, sufficient security is achieved.

In the device according to FIG. 3a, the guide plate 2 is provided with an insert 20 in the main system and printing area for the letter 3.
The insert 20 expediently consists of a piece of rustproof metal, into which all the required structures are stamped or stamped, see FIG. 3b.
Above and below the recesses 201, 202 for the ink print head 4, slide rails 203 are formed continuously over the entire length of the insert 20. The opening 206 is provided for the sensor 7.
In order to ensure secure letter transport, in particular jam due to snagging is avoided, the area 204 in front of the recesses 201, 202, the nozzle plane 40 of the ink print head 4, and the area 205 thereafter are arranged in a staggered manner, see FIG. 3c.
If corresponding deep-drawing sheet metal is used for the production of the insert 20, the implementation is unproblematic.

4, the guide plate 2 is provided with recesses 21, 22 which are open at their downstream end in the direction of transport. In a simple manner, smearing of the printed image and jamming of the letter are avoided.

Reference symbols used

1

Conveyor belt

10th

Belts, timing belts

11

Roller, tooth roller

2nd

Guide plate

20th

Use in the guide plate 2

201

first recess in use 20

202

second recess in use 20

203

Slide rails on insert 20

204

Area in front of the recess (es) 201, 202

205

Area after the recess (es) 201, 202

206

Opening for sensor 7 in use 20

21

first recess in guide plate 2 for ink print head 4

22

second recess in guide plate 2 for ink print head 4

23

Slide rails on the guide plate 2

231

Slide rails in the area 25, 26

24th

Area in front of the recess (es) 21, 22

25th

Area of the guide plate 2 after the recess 21

26

Area of the guide plate 2 after the recess 22

3rd

Print carrier, letter

31

Edge, contact edge of the print carrier 3

32

Surface, contact surface of the pressure carrier on the guide plate 2

4th

Ink printhead

40

Nozzle level of the ink print head

5

Incremental encoder

6

Photocell

7

Sensor for letter start detection or for triggering pressure

a

Distance between slide rails 231 in the area 25, 26

b

Print image width

d

Thickness of the slide rails 231 or back offset of the area 25, 26

w

Curvature of the print carrier 3 in the printed area

α

Inclination angle of the guide plate 2 from the plumb line

Claims (14)

Device for printing a print carrier (3) standing on an edge (31), in particular a letter in franking and / or addressing machines, with a guide plate inclined with respect to the vertical with a recessed area for a printing device, characterized in that - That the recessed area has at least one recess (21, 22) and the recess (21, 22) in the transport direction to the downstream end following area (25, 26) of the guide plate (2) is designed so that the pressure carrier (3rd ) is exposed at this point, - That the printing device is an ink printing arrangement with a nozzle plane (40) extending parallel to the guide plate (2), and the ink arrangement is positioned in a stationary manner during the printing process, - That the inclination of the guide plate (2) with respect to the vertical is at most 45 ° and - That means (1) for applying a feed force to the pressure carrier (3) for feed in the transport direction along the guide plate (2) are provided. Device according to claim 1, characterized in
that a continuously revolving conveyor belt (1) is provided, the conveying plane of which extends orthogonally to the guide plate and on which the print carrier standing on the edge and supported against the guide plate due to its own weight is conveyed in a transport direction. Device according to claim 1, characterized in
that the area (25) of the guide plate (2) following the recess (21, 22) in the direction of transport towards the downstream end is set back relative to the contact surfaces for the pressure carrier (3). Device according to claim 3, characterized in
that the guide plate (2) in the area (25, 26) after the recess (21, 22) either by mechanical shaping or ablation relative to the contact surface for the pressure carrier (3) by a depth (d) is set back, which is larger than the largest curvature (w) to be expected of the printing medium (3) in the printed area. Device according to claim 1, characterized in
that the recessed area has at least one recess (21, 22) which is open towards the downstream end in the transport direction. Device according to claim 1, characterized in
that the guide plate (2) is a flat plate on which the pressure carrier (3) bears with a surface (32) and
that the print carrier (3) has an edge (31) on the conveyor belt (1). Apparatus according to claim 1 and 6, characterized in
that the guide plate (2) is a plate provided with slide rails (23, 231) in the transport direction, and
that in the area (25, 26) after the recess (21, 22) the slide rails (231) are at a distance (a) larger than the printed image width (b) and a thickness (d) larger than the largest curvature to be expected (w) of the print carrier (3) in the printed area. Device according to claims 1, 3, 4 and 7, characterized in that
that the guide plate (2) has an insert (20) with at least one recess (201, 202) and molded-in slide rails (203), which consists of a stainless metal. Device according to claims 1 and 6 to 8, characterized in that
that the contact surface on the guide plate (2, 20) for the pressure carrier (3) is polished. Device according to claims 1, 3, 4 or 8, characterized in that
that the area (204) in front of the recess (21, 201, 22, 202), the nozzle plane (40) of the ink print head (4) and the subsequent area (25, 205) are staggered in a row. Device according to claim 1, characterized in
that the inclination of the guide plate (2) relative to the vertical is 18 ^o . Arrangement according to claim 1 or 8, characterized in
that the recessed area comprises two recesses (21, 201, 22, 202) and the ink printing arrangement comprises two ink printing heads (4), each recess (21, 201, 22, 202) being permanently assigned an ink printing head (4). Arrangement according to claim 1 or 8, characterized in
that the recessed area has two recesses (21, 201, 22, 202) and the ink printing arrangement comprises a single ink printing head (4) which is optionally assigned to one of the two recesses (21, 22) and is height and side adjustable. Arrangement according to claim 1, characterized in
that the circulating conveyor belt (1) consists of a toothed belt and two toothed rollers (11), of which the driving roller is arranged in the vicinity of the printing area and is arranged together with an incremental encoder (5) on one axis.

Images