Digital printing machine

Abstract

The invention relates to a digital printing machine, comprising: a print head unit (1) with nozzles (2) for printing a substrate conveyed in a conveying direction (3); the invention relates to a device (1) for conveying a nozzle (2) in a conveying direction (3), and a cover element (4) which can be adjusted into an opposite position (6) in which the cover element (4) is located opposite the nozzle (2), characterized in that the cover element (4) can be adjusted into the opposite position (6) in a transverse direction (5) transverse to the conveying direction (3); the cover element (4) has a row of liquid chambers (7) which are separated from each other by an intermediate wall (8) and open upwards; and the rows extend in the transverse direction (5).

Description

Technical Field

[0001] The present invention relates to a digital printing press, comprising: a printhead unit with a nozzle for printing a substrate conveyed in a conveying direction; and a capping element adjustable to an opposite position in which the capping element is located opposite the nozzle. Background Technology

[0002] In inkjet printers, capping elements are used to cover the nozzles of the printhead when printing is interrupted. Liquid-filled capping elements are known in the prior art (US2010 / 0171789A1, DE102016222960A1). When the capping element is positioned opposite the nozzle, the liquid evaporates near the nozzle, thus preventing the ink in the nozzle from drying out. Summary of the Invention

[0003] The objective of this invention is to provide an alternative digital printing press.

[0004] The task is accomplished by a digital printing press comprising: a printhead unit with nozzles for printing on a substrate conveyed in a conveying direction; and a capping element adjustable to an opposite position, in which the capping element is located opposite the nozzles, characterized in that the capping element is adjustable to the opposite position transversely to the conveying direction; the capping element has a row of liquid chambers spaced apart from each other by a central wall and opening upwards; and the row extends transversely.

[0005] One advantage of this invention is that the capping element can be horizontally and linearly adjusted along the direction of a row of liquid chambers, even at high adjustment speeds, without the risk of liquid "overflow". Through horizontal linear adjustment, the capping element can be moved from a position not opposite the nozzle to the opposite position.

[0006] The following extension schemes can be implemented individually or in any combination:

[0007] In one extended design, a channel exists in the lower region of the intermediate wall through which liquid can flow from one liquid chamber to another.

[0008] In another extension, the capping element has a bottom and the channel is defined by the bottom and one of the intermediate walls.

[0009] In another extension, the bottom has an inclination along or against the lateral direction.

[0010] In another extension, the capping element has an outlet for liquid and the bottom slopes or slopes toward the outlet.

[0011] In another extension, the capping element is arranged in a carriage that is mounted to be movable along the lateral direction.

[0012] In another extension, the slider is designed as a collection tray for collecting liquid, into which the capping element is placed.

[0013] In another extended embodiment, there is a gap between the outer wall of the capping element and the outer wall of the collection tray, through which liquid overflowing from the capping element can drain into the collection tray.

[0014] In another extended embodiment, a cleaning device for cleaning the components of the printhead unit is arranged on the carriage.

[0015] In another extension, the printhead unit has one or more unique printheads.

[0016] In another extended embodiment, the printhead unit is arranged in a set of such printhead units, and the capping element is arranged in a set of such capping elements, each capping element being configured for a different printhead unit.

[0017] In another extended scheme, there is a common drive mechanism for simultaneously adjusting all the capping elements in the capping element group to their respective opposite positions. Attached Figure Description

[0018] Further extensions can be derived from the following description of the embodiments and related figures.

[0019] In the attached image:

[0020] Figures 1a to 1c This shows a set of capping elements in different positions on a digital printing press, and

[0021] Figure 2 and Figure 3 Different views of the set of capping elements are shown. Detailed Implementation

[0022] The digital printing press has a row of printhead units 1, also known as print strips. Each printhead unit 1 includes multiple printheads with nozzles 2 for inkjet printing. The nozzles 2 face downwards and print on the substrate as it passes along the transport direction 3. The substrate can be sheets of paper transported on a conveyor belt or tray. Each printhead unit 1 is equipped with a capping element 4 having a row of liquid chambers 7 extending laterally 5.

[0023] Figure 2 A top view of one of the sealing elements 4 is shown. Figure 3 It is along Figure 2 The cross-sectional view of line III-III in the diagram.

[0024] The capping element 4 has an inlet 11 and an outlet 12 for liquid 20, through which the liquid circulates. The bottom 10 slopes from one end of the capping element 4 (where the inlet 11 is located) to the other end. This slope facilitates the discharge of ink-contaminated liquid 20.

[0025] The capping element 4 is divided into liquid chambers 7 by an intermediate wall 8. The liquid chambers 7 are interconnected or communicate with each other by channels 9, which are formed between the bottom 10 and the intermediate wall 8. The channels 9 are sized to allow volumetric flow, thereby allowing the filling liquid levels in the liquid chambers 7 to slowly equalize with each other without creating waves.

[0026] from Figures 1a to 1c As can be seen, the capping elements 4 are placed into the collection tray 13 with the gap 14 formed. If liquid 20 overflows from the capping elements 4 and flows into the gap 14 due to a malfunction, the liquid 20 is collected by the collection tray 13, thereby additionally protecting the substrate conveying device arranged below the collection tray from contamination.

[0027] The collection tray 13 forms a carriage, on which a cleaning device 15 is also arranged. When the slider with the cleaning device 15 moves laterally 5, the cleaning device 15 cleans the nozzle 2 or the nozzle plate into which the nozzle 2 is inserted. The collection tray 13 can also collect liquid overflowing from the cleaning device 15.

[0028] The collection tray (carriage) 13 is mounted on a common frame 16, which can be moved laterally 5 via a threaded spindle 19 by a drive device 18. For this purpose, the frame 16 is movably mounted in a frame 17. Therefore, the sealing elements 4 can be jointly moved from a passive position ( Figure 1a ) via the middle position ( Figure 1b Adjust to the active position or the opposite position 6 ( Figure 1c Then adjust it back. In the opposite position 6, the corresponding capping element 4 is positioned opposite all the nozzles 2 of the associated printhead unit 1 and is not yet or no longer in the intermediate position. In the passive position, the capping element 4 is horizontally offset or staggered relative to the printhead unit 1 and its nozzles 2.

[0029] In the opposite position 6, the capping element 4 is positioned opposite the printhead unit 1, such that the nozzle 2 of the printhead unit faces the upward-opening capping element 4. Liquid 20 evaporating from the capping element 4 deposits on the printhead unit 1 and wets the nozzle 2, preventing it from drying out during printing interruptions.

[0030] One advantage of the system shown is that the adjustment of the capping element 4 from a passive position to an active position and back can be performed relatively quickly, thus reducing maintenance time. This high-speed adjustment is possible because the total volume of liquid 20 in the capping element 4 is subdivided into smaller volumes, thereby counteracting wave formation and overflow. The smaller sub-volumes allow the capping element 4 to be adjusted under large positive and negative accelerations without generating large waves in the liquid 20.

[0031] The following modifications, not shown in the diagram, are also feasible:

[0032] The orientation of the intermediate wall 8 can be slightly inclined to the vertical line, rather than vertically oriented.

[0033] The channel 9 between the bottom 10 and the middle wall 8 is not in the form of a gap, but can be in the form of a hole or groove in the middle wall 8.

[0034] However, the channel 9 bounded by the bottom 10 shown in the figure is more conducive to self-cleaning.

[0035] List of reference numerals in the attached diagram:

[0036] 1 Printhead Unit

[0037] 2 nozzles

[0038] 3 Conveying direction

[0039] 4 sealing elements

[0040] 5 horizontal

[0041] 6 Opposite position

[0042] 7 liquid chambers

[0043] 8 intermediate walls

[0044] 9 channels

[0045] 10 bottom

[0046] 11 entrances

[0047] 12 Exports

[0048] 13 Collection trays (carriages)

[0049] 14 gaps

[0050] 15 Cleaning equipment

[0051] 16 Framework

[0052] 17 racks

[0053] 18. Drive unit

[0054] 19 Threaded spindle

[0055] 20. Liquid.

Claims

1. A digital printing press, comprising: A print head unit (1) with a nozzle (2) is used to print on a substrate conveyed along the conveying direction (3); and a capping element (4) adjustable to an opposite position (6), in which the capping element (4) is located opposite the nozzle (2), characterized in that, The sealing element (4) can be adjusted laterally (5) to the opposite position (6) in the transverse direction (3); The sealing element (4) has a row of liquid chambers (7), which are spaced apart from each other by a middle wall (8) and open upwards; and The row extends along the transverse direction (5).

2. The digital printing press according to claim 1, characterized in that, A channel (9) exists in the lower region of the intermediate wall (8), through which liquid (20) can flow from one liquid chamber (7) to another.

3. The digital printing press according to claim 2, characterized in that, The capping element (4) has a bottom (10); and The channel (9) is bounded by one of the bottom (10) and the intermediate wall (8).

4. The digital printing press according to claim 3, characterized in that, The bottom (10) has an inclination along the transverse direction (5) or against the transverse direction.

5. The digital printing press according to claim 4, characterized in that, The capping element (4) has an outlet (12) for the liquid (20); and The bottom (10) slopes downward toward the outlet (12).

6. The digital printing press according to any one of claims 1 to 5, characterized in that, The capping element (4) is arranged on a carriage that is mounted to be movable along the lateral direction (5).

7. The digital printing press according to claim 6, characterized in that, The sliding structure creates a collection tray (13) for collecting liquid (20); and The capping element (4) is placed into the collection tray (13).

8. The digital printing press according to claim 7, characterized in that, There is a gap (14) between the outer wall of the capping element (4) and the outer wall of the collection tray (13), through which liquid (20) overflowing from the capping element (4) can flow into the collection tray (13).

9. The digital printing press according to any one of claims 6 to 8, characterized in that, A cleaning device (15) for cleaning the components of the printhead unit (1) is arranged on the carriage.

10. The digital printing press according to any one of claims 1 to 9, characterized in that, The printhead unit (1) has one or more unique printheads.

11. The digital printing press according to any one of claims 1 to 10, characterized in that, The printhead unit (1) is arranged in a set of such printhead units (1). The sealing element (4) is arranged in a set of such sealing elements (4); and Each capping element (4) is assigned to a different printhead unit (1).

12. The digital printing press according to claim 11, characterized in that, There is a common drive unit (18) for simultaneously adjusting all the capping elements (4) in the capping element (4) group to their respective opposite positions (6).

Images