DEVICE FOR CONVEYING FLAT PIECES

Abstract

The present application relates to a device for conveying flat pieces. The device comprises a belt with a transport surface, wherein the belt is movable along a transport axis; a support element with a support surface for supporting the belt; and a vacuum supply for providing vacuum suction; wherein a suction distributing structure at the support surface of the support element is in fluid connection with the vacuum supply; and wherein the suction distributing structure has a belt suction region and a card suction region, wherein the belt suction region is configured to provide suction to the belt and the card suction region is configured to provide suction to flat pieces on the transport surface of the belt. The present application also relates to a system for treating flat pieces, the system comprising a treatment device, for example a print head.

Claims

1-12. (canceled)

13. A device for conveying flat pieces, the device comprising: a belt with a transport surface, wherein the belt is movable along a transport axis; a support element with a support surface for supporting the belt; and a vacuum supply for providing vacuum suction; wherein a suction distributing structure at the support surface of the support element is in fluid connection with the vacuum supply; and wherein the suction distributing structure has a belt suction region and a card suction region, wherein the belt suction region is configured to provide suction to the belt and the card suction region is configured to provide suction to flat pieces on the transport surface of the belt.

14. The device of claim 13, wherein the fluid connection with the vacuum supply in the belt suction region has a lower flow resistance than in the card suction region.

15. The device of claim 13, wherein the belt has openings that are configured such that, when the device is operated, the openings are arranged corresponding to the card suction region of the suction distributing structure.

16. The device of claim 15, wherein: the openings are configured such that they have a pattern with periodic units that repeat periodically along the transport axis; and the periodic units are configured such that at least one opening of the periodic unit is arranged in fluid connection with the vacuum supply while the belt is transported over the support element.

17. The device of claim 15, wherein the belt has a continuous region that is arranged, when the device is operated, corresponding to the belt suction region of the suction distributing structure.

18. The device of claim 13, wherein the vacuum supply comprises a channel in the support element along the transport axis.

19. The device of claim 13, wherein the suction distributing structure comprises a channel with a varying cross-section area, wherein the cross-section area is lower in the card suction region than in the belt suction region.

20. The device of claim 17, wherein the suction distributing structure comprises an elongated channel in the card suction region.

21. The device of claim 13, wherein: the fluid connection of the suction distributing structure with the vacuum supply comprises a first channel with a first cross-section for supplying the belt suction region and a second channel with a second cross-section for supplying the card suction region; and the second cross-section is smaller than the first cross-section.

22. The device of claim 13, wherein the flat pieces are plastic cards.

23. The device of claim 13, wherein the support element is formed by at least two support element modules.

24. A system for treating flat pieces, the system comprising: a treatment device; and a device for conveying the flat pieces, the device comprising: a belt with a transport surface, wherein the belt is movable along a transport axis; a support element with a support surface for supporting the belt; and a vacuum supply for providing vacuum suction; wherein a suction distributing structure at the support surface of the support element is in fluid connection with the vacuum supply; and wherein the suction distributing structure has a belt suction region and a card suction region, wherein the belt suction region is configured to provide suction to the belt and the card suction region is configured to provide suction to flat pieces on the transport surface of the belt; wherein the treatment device is arranged to perform a treatment on a given flat piece that is conveyed by the device for conveying.

25. The system of claim 24, wherein the treatment device is arranged to perform the treatment on a surface of the given flat piece.

26. The system of claim 25, wherein the treatment device comprises a print head.

27. The system of claim 26, wherein the belt has openings arranged corresponding to the card suction region of the suction distributing structure.

28. The system of claim 27, wherein the belt has a continuous region that is arranged corresponding to the belt suction region of the suction distributing structure.

29. The system of claim 28, wherein the suction distributing structure comprises a channel with a varying cross-section area, wherein the cross-section area is lower in the card suction region than in the belt suction region.

30. The system of claim 28, wherein the suction distributing structure comprises an elongated channel in the card suction region.

31. The system of claim 28, wherein: the fluid connection of the suction distributing structure with the vacuum supply comprises a first channel with a first cross-section for supplying the belt suction region and a second channel with a second cross-section for supplying the card suction region; and the second cross-section is smaller than the first cross-section

32. The system of claim 24, wherein the support element is formed by at least two support element modules.

Description

[0064] The invention is described further on the basis of the attached figures. Therein, the figures show:

[0065] FIG. 1 a perspective view of an embodiment of the device;

[0066] FIGS. 2A to 2D schematic views of details of the device;

[0067] FIG. 3 a cross-sectional view of the device;

[0068] FIGS. 4A and 4B schematic views of the suction distributing structure and the belt; and

[0069] FIGS. 5A and 5B perspective views of the modular support element structure.

[0070] Turning to FIG. 1, a perspective view of an embodiment of the device is described.

[0071] The device 10 of this embodiment is part of a system for treating flat pieces 11. More specifically, the system is used to treat the plastic cards 11 by printing on them and performing other operations such as laser engraving, laminating etc. Of course, the invention is not limited to such a system.

[0072] The device 10 has a base 22, on which several other elements are mounted.

[0073] The device comprises a belt 12, which is a metal belt 12.

[0074] The metal belt 12 is configured as an endless loop and movably engaged with a driven roller 18, which is rotated by a dedicated motor unit.

[0075] At the opposite end of the device 10, a tensional idler 20 holds the belt 12 tightly. Hereby, variations of the length of the belt 12, e.g., due to temperature changes, can be compensated to avoid a loose belt 12 and to thus avoid slippage between the belt 12 and the driven roller 18.

[0076] By the driven roller 18 and the tensioned idler 20, the belt 12 is held straight along a transport axis TA and can be moved such that an object lying on the top side of the belt 12, which is configured as a transport surface 12a, can be transported.

[0077] In the system of the embodiment, a feed-in device is used to put a card 11 onto the belt 12 at the side of the tensioned idler 20, and the card 11 may then be transported along the transport axis TA towards the driven roller 18.

[0078] Between the driven roller 18 and the tensioned idler 20, a support element 14 is arranged. In particular, the support element 14 is positioned between a bottom part of the belt 12 and a top part of the belt 12, which is formed as a loop between the driven roller 18 and the tensioned idler 20. The top part of the loop-shaped belt 12 is supported on a top surface of the support element 14, which is configured as a support surface 14a.

[0079] In the present embodiment, a card ruler 24 is attached to the device 10 in proximity to the belt 12 and with an edge that is parallel to the transport axis TA. The card ruler 24 is used to ensure a proper positioning of the flat piece 11, as it glides along the parallel edge of the card ruler 24. In the embodiment, rollers are provided to push the flat piece 11 against the card ruler 24 after the flat piece 11 has been fed onto the transport surface 12a of the belt 12. Between the rollers and the card ruler 24, vacuum suction is built up such that a suction force is achieved to hold the flat piece 11 relative to the transport surface 12a of the belt 12.

[0080] In the embodiment, the support element 14 is formed with support element modules 40, as explained below with respect to FIGS. 5A and 5B.

[0081] The support element 14 of the embodiment is manufactured in a two-step process: First, additive manufacturing, in particular 3D-printing, is used to produce a raw piece of the support element 14 or its modules. Subsequently, milling and/or drilling techniques are used to produce a smooth support surface 14a at the top of the support element 14, and to form further structures of the support element 14, which are explained in detail below.

[0082] Within the support element 14, a channel 15 is formed, which will be explained in greater detail below. To this channel 15, a vacuum supply 16 is connected, in particular a connection to a vacuum pump.

[0083] Turning to FIGS. 2A to 2D, schematic views of details of the device are described.

[0084] In the schematic exploded view of FIG. 2A, a card 11 is shown as the top element of the setup.

[0085] A section of the belt 12 is shown with the transport surface 12a on top.

[0086] The belt 12 has openings 13, which are arranged within regions at the outer edges of the belt 12 and in the middle of the belt 12.

[0087] When the device 10 is in operation, the card 11 is lying on the transport surface 12a of the belt 12, while the belt 12 is movable along the transport axis TA.

[0088] Below the belt 12, a section of the support element 14 is shown, with a support surface 14a on top.

[0089] When the device 10 is in operation, the belt 12 is in contact with the support surface 14a such that a certain friction is reached between the two. Such friction secures the belt 12 against displacement in a direction perpendicular to the transport axis TA.

[0090] A channel 15 is formed in the support element 14. This channel 15 is running essentially in a longitudinal direction of the support element 14, i.e., parallel to the transport axis TA.

[0091] The channel 15 is connected to the vacuum source 16, as shown above with respect to FIG. 1. Thus, a pressure below the surrounding air pressure can be generated with in the channel 15.

[0092] In further embodiments, the channel 15 can be formed between the support element 14 and the base 22. For example, complementary parts of a channel 15 may be formed in the support element 14 and the base 22, such that the channel 15 is closed, when the support element 14 is mounted on the base 22.

[0093] At the support surface 14a of the support element 14, a suction distributing structure 30 is formed. In general, the suction distributing structure 30 of the embodiment comprises indentations, open channels, grooves and deepened regions that are formed in the support surface 14a.

[0094] The suction distributing structure 30 is in fluid connection with the channel 15.

[0095] For facilitating the fluid connection, a channel 17 is used, which connects an opening in a wall of the channel 15 towards the vacuum source 16, and an opening 17a at the support surface 14a. Thus, air can be drawn from the environment into the channel 15, as long as a sufficiently low pressure is provided in the channel 15. Thus, a resulting suction extends towards the opening 17a, when an object is placed above the support surface 14a close to the opening 17a or the suction distributing structure 30.

[0096] When the device 10 is operated and vacuum is provided by the vacuum supply 16, suction is produced in distinct ways:

[0097] Where the belt 12 covers a part of the suction distributing structure 30, the suction is generated by this part of the suction distributing structure 30. As a result, the belt is pulled towards the support element 14.

[0098] Where an opening 13 of the belt 12 is arranged above the suction distributing structure 30, and a card 11 is covering the opening 13, the card is pulled towards the belt 12 and the support element 14.

[0099] Where an opening 13 of the belt 12 is arranged above the suction distributing structure 30, but the opening 13 is not or not completely covered by a card, surrounding gas is drawn in through the opening 13. Thus, some under-pressure in the channel 15 and suction in the suction distribution structure 30 may be lost.

[0100] In order to prevent a too great loss of suction or under-pressure in the channel 15, the suction distribution structure 30 is formed with high-resistance structure elements 30a and low-resistance structure elements 30b. These are schematically shown in FIG. 2B.

[0101] The high-resistance structure elements 30a are formed such that, when they are not or only partially covered with respect to the atmospheric pressure of the environment, a fluid flow through these structure elements 30a is acting against a higher flow resistance than in other parts of the suction distribution structure 30. Thus, incoming fluid is drawn in relatively slowly and only a small part of the pressure gradient is lost.

[0102] Such a high flow resistance can be reached, e.g., by narrow, deep and/or long structures. Therefore, in the embodiment, the high-resistance structure elements 30a comprise an elongated, narrow open channel 30a. When an opening 13 of the belt 12 is positioned above this part of the suction distribution structure 30, and the opening 13 is not covered or only partially covered, air is sucked in, but at a relatively small rate. Also, suction may be exerted to the belt 12 in areas, where the belt material covers the narrow open channel 30a.

[0103] Thus, the belt 12 is configured such that the openings 13 in a region 32a of the belt 12 are arranged above a high-resistance region 31a of the support surface 14a. This is a card suction region 31a, where suction can be applied to a card 11 on the transport surface 12a of the belt 12. If a card 11 is present above an opening 13, it is held down by suction; if no card 11 is present, the high-resistance properties of the suction distributing structure 30 makes sure that not too much pressure is lost.

[0104] Also, it is avoided that a leakage air flow is disturbing other processes. For example, ink droplets of an inkjet printer may be considerably deflected by an air flow that is caused by uncovered openings 13, in particular in regions close to an edge of a card 11.

[0105] On the other hand, the low-resistance structure elements 30b are configured to provide a strong suction, since a fluid flow through these structure elements 30b is acting against a lower flow resistance, compared to the high-resistance structure elements 30a. Thus, a fluid may be sucked into the channel 15 at a higher rate than through the high-resistance structure elements 30a. When such a low-resistance structure element 30b is not or only partially covered with respect to the atmospheric pressure of the environment, a higher incoming fluid is drawn and a larger part of the pressure gradient is lost. The belt 12 is therefore configured to avoid such a situation, by providing a continuous region without openings 13.

[0106] Such a low flow resistance can be reached by wider structures. Therefore, in the embodiment, the low-resistance structure elements 30b comprise wide open channels 30b and patches, where the support surface 14a is deepened. In the embodiment, the belt 12 is configured such that no openings 13 are positioned above this part of the suction distribution structure 30, and a continuous region 32b of the belt 13 is covering these low-resistance structure elements 30b instead. Thus, the belt 12 itself is pulled towards the support surface 14a by suction in the low-resistance region 31b, and a belt suction region 31a is provided.

[0107] The effect of higher or lower flow resistance may be envisioned by an example: At the same pressure gradient, an air flow will overcome the low-resistance structure elements 30b with at least the double flow rate compared to a high-resistance structure element 30a of the suction distributing structure 30.

[0108] In another example, if a high-resistance structure element 30a is not covered by a flat piece 11 or the belt 12, a resulting leakage air flow through the high-resistance structure element 30a is lower than it would be for a low-resistance structure element 30b.

[0109] FIGS. 2B and 2C show the support element 30 from above (FIG. 2B) and in a cross-section across the plane A-A (FIG. 2C). The high-resistance regions 31a, which serve as card suction regions 31a, and the low-resistance regions 31b, which serve as belt suction regions 31b, are indicated by dotted lines.

[0110] In the cross-section of FIG. 2C, channels 17 are shown, which implement the fluid connection between the suction distributing structure 30 at the support surface 14a and the channel 15, which is connected to the vacuum supply 16. The channel 17 ends at the support surface 14a in an opening 17a. This opening 17a can be used as a vacuum control hole 17a, which may for example be sealable partially or totally by a mechanism to reduce suction, if needed. In particular, a cross-section area of the opening 17a can be adjusted or a valve can be used to configure the openings 17a for the predetermined properties. Also, the cross-section and/or length of the channel 17 can be adjusted such that the predetermined flow resistance is obtained. In further embodiments, more channels 17 may be provided.

[0111] In another embodiment, a high-resistance structure element 30a may be configured with a long and/or narrow channel 17 for fluid communication with the channel 15, which is connected to the vacuum supply 16. On the other hand, the channel 17 for a low-resistance structure element 30b may be wider and/or shorter. By such a configuration, the communication channel 17 itself can have a smaller or larger flow resistance. By these properties of the channel 17, similar structural configurations of the high- 30a and low-resistance structure elements 30b can be used and modified by varying the channel 17 design.

[0112] Also, the flow resistance properties of the channel 17 can be used to influence the flow resistance in addition to the properties of structure elements 30a, 30b themselves. In other words, the balance of the restrictions for the air flow through the channel 17 and the structures 30a, 30b defines a local pressure gradient and flow in situations with openings 13 covered by flat pieces 11, or openings 13 that are not covered and allow free air inflow.

[0113] FIG. 2D shows the belt 12 of the embodiment in a schematic top view. Only some of the openings 13 are shown for clarity.

[0114] The openings 13 of the belt 12 are arranged in regions 32a with openings 13, while other regions 32b are continuous and free of openings 13. These regions 32a, 32b are defined as band-shaped regions 32a, 32b of the belt 12, running parallel to the transport axis TA.

[0115] The belt 12 is arranged on the support surface such that the regions 32a with openings 13 essentially coincide with the high-resistance regions 31a of the suction distributing structure 30. In addition to that, the continuous belt regions 32b essentially coincide with the low-resistance regions 31b of the suction distributing structure 30. Thus, the low-resistance structure elements 30b are always covered by the continuous belt regions 32b. Also, uncovered openings 13 can only occur above the high-resistance structure elements 30a. Thus, pressure loss and leakage air flow are reduced due to the high flow resistance, which has to be overcome by an incoming fluid.

[0116] Further details on the arrangement and configuration of openings 13 are explained below.

[0117] Referring to FIG. 3, a cross-sectional view of the support element 14 and belt 12 is shown, together with parts of a perspective view. Similar elements are shown, which have already been described above with reference to FIGS. 2A to 2D. The following description is thus focused on elements, which have not been described before in greater detail.

[0118] In the cross-section, the material of the support element 14 is shown. In the present embodiment, the support element 14 is made from a polymer material.

[0119] Above the support element's 14 top surface 14a, the belt 12 is arranged. While the device 10 is operated, the belt 12 glides over the top surface 14a of the support element 14.

[0120] The belt 12 has openings 13.

[0121] An opening 17a is formed at the support element's 14 top surface 14a, leading to a closed channel 17, where another end of the channel 17 is provided. This closed channel 17 extends downwards towards the vacuum supply 16 and another closed channel 15 within the support element 14, respectively, which distributes vacuum along the length of the support element 14.

[0122] The opening 17a and the closed channel 17 thus provide a fluid connection between the suction distributing structure 30, which is formed at the surface 14a of the support element 14, and the closed channel 15 within the support element 14, which distributes the vacuum or under-pressure along the support structure 14. Thus, an air flow 34 can enter through openings 13 of the belt 12, flow through a high-resistance 30a and/or a low-resistance structure element 30b of the suction distributing structure 30, and reach the opening 17a, the channel 17 and the next channel 15.

[0123] If the opening 13 is covered by a flat piece 11, suction is generated below it and a suction force is generated, pulling the flat piece 11 towards the belt and the support element 14. In the embodiment, this mechanism is mainly provided in a cooperation of the openings 13 of the belt 12 and the high-resistance structure elements 30a.

[0124] In a similar way, if the suction distributing structure 30 is covered by a continuous region of the belt 12, a suction force is provided to pull the belt 12 towards the support surface 14a. In the embodiment, this mechanism is mainly provided in a cooperation of the belt 12 and the low-resistance structure elements 30b.

[0125] With reference to FIGS. 4A and 4b, the interplay between the belt 12 and its openings 13 with the suction distributing structure 30 is described.

[0126] Herein, FIG. 4A is a more schematic view, reduced to only four openings 13 of the belt 12 and two parts of the suction distributing structure 30. FIG. 4B is a more complete view of the structure in a top-view.

[0127] As shown in FIG. 4A, the openings 13 of the belt are arranged shifted with respect to each other along the transport axis TA, which coincides with the longitudinal axis of the belt 12.

[0128] The arrangement of this set of four openings 13 is made such that it is repeated with a defined period length, resulting in a periodic unit Pu.

[0129] In the example of FIG. 4A, the openings 13 are shifted in the direction along the transport axis TA in regular distances, i.e., at shift lengths of ¼*Pu. In other embodiments, other shift lengths and/or irregular shift lengths may be used.

[0130] In the embodiment, the suction distributing structure 30 is extending essentially along an axis Y perpendicular to the transport axis TA.

[0131] It comprises high-resistance structure element 30a, in this example formed with larger structures like rounded pads and deepenings in the support surface 14a, and low resistance structure elements 30b, in this example formed as elongated channels along the width of the belt 12.

[0132] The belt 12 and its openings 13 are arranged such that, when the belt 12 is moved over the support surface 14a, the openings 13 are moved across the channels of the high-resistance structure elements 30a. On the other hand, a continuous region of the belt 12 is moved across the low-resistance structure elements 30b.

[0133] FIG. 4B shows more details of the arrangement of the belt 12 and the openings 13 formed therein, in relation to the suction distributing structure 30 of the support surface 14a.

[0134] In the embodiment, the openings 13 have an oval form and are longer in the longitudinal direction TA than along the width Y of the belt 12.

[0135] In this exemplary embodiment, the openings 13 are formed with different parameters, depending on their position at the lateral edges of the belt 12 or in the middle region. At the edge of the belt 12, openings 13a are configured with the same length along the transportation axis TA, but with smaller width, thus more elongated than openings 13b in the middle region. At the same time, the openings 13a, 13b have the same length along the transport axis TA. Thus, the individual openings 13a, 13b extend over a larger area in the middle region of the belt 12 than at the edges.

[0136] In the embodiment, this distribution of the openings 13 has the advantage of productively guiding any leakage air flow towards the low-resistance structure elements 30b, e.g., air leaking in between the support surface 14a and the underside of the belt 12. According to the embodiment, the continuous region 32b of the belt 12 is arranged between the regions 32a with openings 13a at the edge and openings 13b in the middle region of the belt 12. Thus, any leakage air flow streaming to a low-resistance region 31b, which is arranged below a continuous region 32b of the belt 12, contributes to the suction in the regions 32a with openings 13a, 13b, and thus to the holding force for flat pieces 11 above the openings 13a, 13b. In particular, the openings 13a, 13b of the belt 12 are arranged so close to each other that a leakage air flow will be drawn from these openings 13a, 13b. Thus, any leakage air flow is used productively, when a flat piece 11 is placed over the openings 13a, 13b.

[0137] The suction distributing structure 30 has several units, which comprise high-resistance 30a and low resistance structure elements 30b. These units of the suction distributing structure 30 extend essentially over the width Y of the support surface 14a. The units of the suction distributing structure 30 are regularly spaced at intervals Pi along the transport axis TA, in particular a distance Pi of the channels 30a to each other.

[0138] In the present embodiment, the length of the openings 13, 13a, 13b along the transport axis TA is the same in all cases.

[0139] In the embodiment, this length is chosen such that the openings 13, 13a, 13b do not connect two separate units of the suction distributing structure 30, in particular they do not connect two channels forming the high-resistance structure elements 30a. In particular, the length of an openings 13, 13a, 13b is smaller than the interval Pi between two units of the suction distributing structure 30. Thus, it is avoided that overly much pressure is lost through one openings 13, 13a, 13b, which is not covered by a flat piece 11 and thus allows an air inflow.

[0140] Also, the openings 13, 13a, 13b are arranged at intervals Po, in particular a specific distance Po between the trailing edges of the openings 13, 13a, 13b. This distance Po may correspond to or be equal to the length of the periodic unit Pu of FIG. 4A.

[0141] The pattern of openings 13, 13a, 13b of the belt 12 and the suction distributing structure 30 may also be periodic, in particular with a length Pp of the periodic pattern.

[0142] In the present embodiment, period length Pp is shorter than ⅓ of the length of a typically used flat piece 11. Due to the relation of periodic lengths Pi<Po, every periodic length Pp one opening 13 does not have a fluid connection to the suction distributing structure 30. By defining a predetermined periodic length Pp<<length of the flat piece 13, the flat piece 13 has only a minimal loss of suction at these disconnected openings 13, since the openings 13 is only disconnected for a very short period of time, in particular about 1 ms in the present case, depending on the transport speed of the belt 12 relative to the support element 14. With a ratio of Pp>>length of the flat piece 11, the suction force for a flat piece 11 on the belt 12 is essentially constant and only slightly reduced, when one of the openings 13 is disconnected from the suction distributing structure 30.

[0143] In another embodiment, a pattern of openings 13, 13a, 13b of the belt 12 and the suction distributing structure 30 may be provided, where there are no openings 13, 13a, 13b without a fluid connection to the suction distribution structure.

[0144] With reference to FIGS. 5A and 5B, the structure of a modular support element is described in more detail.

[0145] A base 22 is shown, which serves as a carrier for the further elements of the support element 14.

[0146] The support element 14 comprises several support element module 40. One of the support element modules 40 is shown missing, to make the structure of the system better visible.

[0147] The support element modules 40 have a flat support module surface 40a, such that their assembly forms a support surface 14a of the support element 14. When the device 10 is operated, the belt 12 is transported over the support surface 14a.

[0148] The support element modules 40 have an arc-like structure, so that a channel 15 is formed between the assembled support element 14 and the base 22, after fixating the support element modules 40 on the base 22.

[0149] To seal this channel 15 in relation to the environment, and to allow the provision of a vacuum suction through this channel 15, seals 44 are provided at the interfaces between support element modules 40 and the base 22, and seals 42 are provided between the support module end surface 40b at the end portions of the support element modules 40, respectively.

[0150] To fasten and secure the support element modules 40 in relation to the base 22, and to secure their position with respect to each other, bolts 23 are used.

[0151] The modular configuration of the support element 14 allows to easily exchange and/or modify and/or repair individual support element modules 40. This is especially useful, since the friction between the metal belt 12 and the support surface 14a may cause considerable wear of the surface and/or the suction distributing structure 30.

[0152] In the embodiment, three different types of support element modules 40 are provided, namely for providing a beginning section of the support element 14, where flat pieces 11 are fed onto the belt 12, a mid-section of the support element 14, over which the flat pieces 11 on the belt 12 are moved, and an end section of the support element 14, where the flat pieces 11 are removed from the belt 12. A support element module 40 for the mid-section may be used several times, depending on the overall length of the support element 14. The beginning section may be configured such that weaker suction is experienced by flat pieces 11 on a belt above the beginning section, to make sure that flat pieces 11 can be brought into a defined position before fixing the position for the transport on the belt 12.

[0153] Also, a longer support element 14 can easily be provided by using more modules 40, or a shorter support element 14 can be provided by using fewer modules 40 for the device 10.

[0154] In the present embodiment, the support element 14 can be manufactured by 3D-printing and subsequent treatment of the surfaces, e.g. by milling and/or drilling, in particular the support surface 14a and/or openings 17a.

[0155] For example, the support element 14 can comprise a polymer material.

[0156] In particular, milling can be used to provide the flat support surface 14a of the support element 14, in particular with the suction distributing structure 30.

[0157] In some systems of the art, shallow and wide channels have been used in the support surface 14a to distribute suction. Instead, the support element of the embodiment can be configured with relatively narrow and deep channels of the suction distributing structure 30, in order to provide a high-resistance structure element 30a. Such a channel design can allow manufacture with lower tolerances for the air flow. For example, a tolerance of +/−0.1 mm for the machining of a channel, a channel with 0.3 mm depth leads to ca.+/−30% deviation in air flow, which may affect an under-pressure that is generated by means of the channel. On the other hand, the tolerance of +/−0.1 mm for a channel at 1.2 mm depth leads to <10% variation in air flow.

[0158] The present design improves the holding force on flat pieces 11, which can be provided by the suction distributing structure 30 in combination with a suitable belt design: The belt 12 of the device 10 may have a width, which is smaller than the width of the flat pieces 11, in particular at least 60% of the width of the flat pieces 11 to be treated, preferably at least 75%, more preferably at least 85%. Thus, the flat pieces 11 on the belt 12 have a certain overhang over the edges. Thus, it is important to provide sufficient holding force in the middle of the width of the belt 12 to hold the flat pieces 11. In order to improve the holding force in the middle of the belt width, openings 13b may be provided in the middle region, corresponding to a high-resistance region 31a of the suction distributing structure 30 at the support surface 14a of the support element 14. For example, two rows of slots or openings 13 may be provided in the middle of the width of the support surface 14a relative to the transport axis TA.

[0159] Specifically, flat pieces 11 with an uneven surface, e.g., an uneven structure for providing Braille features for blind users, may pose significant challenges for a device 10 to hold a flat piece 11 by suction. The uneven surface may lead to a higher leakage of air into the openings 13 and a weaker sealing between the belt's transport surface 12a and the surface of the flat piece 11 is reached. Thus, higher suction may be necessary to hold such flat pieces 11.

[0160] Similarly, a higher suction may be needed to hold flat pieces 11 with a curvature, e.g., from embedded chips, a perforation, or with small security features or other irregularities of the surface, compared to flat pieces 11 with a perfectly flat surface in contact with the transport surface 12a of the belt 12.

[0161] The embodiment of the device 10 may, for example, be used in a printer, in particular an inkjet printer. Therein, the belt 12 is extending in such a way that the flat pieces 11 on the transport surface 12a are positioned below one or several print heads, where a printing operation is performed.

[0162] By providing suction to the belt 12 as well as the flat pieces 11 on the belt 12, a high precision is secured and, e.g., security features can be applied to the flat pieces 11 with high accuracy.

[0163] By transporting the belt 12 over the support surface 14a, while suction is applied through the suction distributing structure 30, high fiction between the belt 12 and the surface 14a is achieved, leading to lower variances in lateral position. At the same time, flat pieces 11 on the belt's 12 transport surface 12a are held steadily and at a fixed position relative to the belt 12.

[0164] In addition to or instead of printing, other treatments may be performed on the flat pieces 11, e.g., laser engraving, laminating, curing, programming of a chip, including further security features or similar.

REFERENCE NUMERALS

[0165] 10 Device [0166] 11 Flat piece; plastic card [0167] 12 Belt [0168] 12a Transport surface [0169] 13 Opening [0170] 13a Opening (edge of the belt) [0171] 13b Opening (middle of the belt) [0172] 14 Support element [0173] 14a Support surface; top surface (or the support element) [0174] 15 Closed channel [0175] 16 Vacuum supply; connection to vacuum pump [0176] 17 Closed channel [0177] 17a Vacuum control hole; opening [0178] 18 Driven roller [0179] 20 Tensioned idler [0180] 22 Base [0181] 23 Bolt [0182] 24 Card ruler [0183] 30 Suction distributing structure [0184] 30a High-resistance structure element; narrow open channel [0185] 30b Low-resistance structure element; wide open channel; deepening [0186] 31a High-resistance region; Card suction region [0187] 31b Low-resistance region; Belt suction region [0188] 32a Region with openings [0189] 32b Continuous region [0190] 34 Air flow [0191] 40 Support element module [0192] 40a Support module surface [0193] 40b Support module end surface [0194] 42 Seal [0195] 44 Seal [0196] A-A Sectional axis [0197] TA Transport axis [0198] Pi Distance of channels [0199] Po Distance of openings [0200] Pp Period of pattern (belt-support assembly) [0201] Pu Periodic unit (belt openings) [0202] Y Axis