CN108116039B

CN108116039B - Printing machine

Info

Publication number: CN108116039B
Application number: CN201711201247.XA
Authority: CN
Inventors: M·迪瓦斯
Original assignee: Heidelberger Druckmaschinen AG
Current assignee: Heidelberger Druckmaschinen AG
Priority date: 2016-11-28
Filing date: 2017-11-27
Publication date: 2022-03-18
Anticipated expiration: 2037-11-27
Also published as: DE102017219709A1; CN108116039A

Abstract

The invention relates to a printing press comprising a device for coating a printing material with a fluid by means of a roller (7) and further comprising a removal device (19,29) for partially removing the fluid (31) from the roller (7). The removing device has at least one section which can be adjusted and set according to different specifications of the printing material. The segments may be roll segments or suction segments (21, 22).

Description

Printing machine

Technical Field

The invention relates to a printing press comprising a device for coating a printing material with a fluid by means of a roller and further comprising a removal device for removing the fluid from the roller in a partial manner.

Background

In digital and non-digital printing presses, the sheet or web is coated with ink, varnish, or other fluid.

DD 235852 a1 describes a printing press with anilox rollers. Anilox rolls may cause a disturbance known as the Framing phenomenon (Framing) when printing to a gauge smaller than the maximum gauge.

Disclosure of Invention

The object of the invention is to provide a printing press in which the edge phenomenon is reduced or completely eliminated.

This object is achieved by a printing press according to the invention, comprising a device for coating a printing material with a fluid by means of a roller and further comprising a removal device for removing the fluid from the roller in a partial manner, and characterized in that the removal device has at least one section which can be set adjustably according to different specifications of the printing material.

If the format width of the printing material to be processed is smaller than the maximum format width that can be processed in the printing press, the fluid can be removed from the roller by means of the removal device in sections of the roller that lie outside the format width to be processed, so that the edge-banding phenomenon is minimized or even completely avoided.

Other modifications are also possible.

The roll may be provided with cupped, grooved or other textured structures on its circumferential surface.

The rollers and the removal device can be components of a precoating installation which is arranged upstream of the inkjet installation in the direction of transport of the print substrate. Fluid is roll-coated (Aufwalzen) onto the substrate by means of a precoating apparatus and one or more inks are applied to the precoated substrate by means of an ink jet apparatus. Here, the printing press is a hybrid printing press in which a digital printing method (inkjet printing) is used in combination with a non-digital printing method (roll coating). The fluid that is rolled onto the substrate in the pre-coating apparatus may be a primer (Grundierung).

The removal device may have a single section which is supported as: can be adjusted into different positions for adapting the removal device to different format widths of the substrate. When adjusting the section from one position into another, the section is adjusted in a direction parallel to the axis of rotation of the roll. The removal device may also have two sections supported as: can be adjusted laterally into different positions according to different specifications of the printing material. When the two sections are to be positioned according to the specification, they are adjusted towards each other or away from each other according to whether the specification is switched from a larger to a smaller specification or vice versa. The two segments are adjusted in a direction parallel to the roller axis.

Regardless of the number of sections, the removal device may be a pneumatically acting removal device or a mechanically acting removal device.

In the case of a mechanical removal device, the removal device may have a peel blade, and the or each section may be a rolled section (walzensegmenter). One or more roll segments may be in rolling contact with the roll (Abrollkontakt) while partially removing fluid from the roll.

In the case of a pneumatic removal device, the removal device may be configured as a suction device and the or each section may be a suction section.

The removal device can also be both pneumatically and mechanically actuated, wherein the removal device in this case has both one or more scrapers for stripping off the fluid and one or more vacuum sections for sucking in the fluid.

Drawings

Further developments of the invention emerge from the following description of exemplary embodiments and the drawings; the figures show:

FIG. 1: an overall view of a printer with a pre-coating apparatus and an ink jet apparatus;

fig. 2 and 3: a first embodiment of the removal device of the precoat apparatus, wherein fig. 2 and 3 show a side view and a top view, respectively, of the mechanical removal device here; and

fig. 4 and 5: a second embodiment of the removal device of the precoat apparatus, wherein fig. 4 and 5 show a side view and a top view, respectively, of the pneumatic removal device here.

Detailed Description

Fig. 1 shows a printing press 1 for processing a printing material 10 in the form of a sheet. The printing press 1 has a sheet feeder and a sheet receiver, which are not indicated with a reference numeral. A precoat apparatus 2 is arranged between the sheet feeder and the ink jet apparatus 3. The ink jet device 3 comprises a plurality of print heads, shown without reference numerals, for multicolor printing with different colors of pigments. In order to be able to print a high-quality print substrate 10 by means of the inkjet device 3, the print substrate 10 is already fully printed in the precoating device 2

Coated with a fluid. The fluid is so-called primed (Primer) and is acidic. Furthermore, the fluid has a low viscosity, whereby the risk of "edge banding" is particularly high if the countermeasures to be elucidated below are not taken.

In both embodiments shown in fig. 2,3 or 4,5, the precoat apparatus 2 comprises a counter-pressure roller 4 for conveying the printing material 10. The impression cylinder 4 has grippers for gripping and holding the leading edge of the sheet of printing material 10, which grippers are not shown in the figures. In a printing operation, impression cylinder 4 and coating cylinder 5 together form an impression nip (Druckspalt) in which a fluid is applied from coating cylinder 5 onto printing substrate 10. The coating cylinder 5 is tensioned with a rubber blanket 6, the ends of which rubber blanket 6 are held fixed by tensioning strips or shafts which are arranged in one or more tensioning channels of the coating cylinder 5. These tensioning channels and tensioning straps or tensioning shafts are not shown with reference numerals. On the coating cylinder 5, a roller 7 is placed, which roller 7 is described next as an anilox roller 7. The anilox roller 7 sinks into the reservoir of fluid 31 in the upwardly open holding tank 8. The metering blade 9 peels off the excess portion of the fluid 31 obtained from the holding tank 8 by the anilox roller 7 from the anilox roller 7.

Features common to both embodiments are set forth above and are further described separately with respect to the exclusive features of both embodiments.

In the first embodiment according to fig. 2 and 3, the intermediate roller is divided into a first and a

second nip section

11,12 which are equal with respect to both circumference and length. The first and

second nip sections

11,12 are supported as: are each rotatable on a roller axis 14 and are movable along the roller axis 14. Instead of the two roller axes 14, however, a common roller axis can also be provided, the two

roller press sections

11,12 being supported: rotatable and movable on the common roller axis. Each

roller press section

11,12 has a roller lining 13 made of rubber, and each

roller press section

11,12 rests on the anilox roller 7 and simultaneously on the take-away roller 18.

The distance 20 between the two

roller press sections

11,12 corresponds to the format width of the printing material 10, which can vary from print job to print job. The spacing 20 required for each print job is set by axially moving the

roller segments

11,12 inwards or outwards. After the positioning of the

roller sections

11,12, the

roller sections

11,12 are fixed in the desired axial position against displacement by means not shown in the figures. The anilox roller 7 carries the fluid 31 from the holding tank 8 over its entire length, whereas the fluid is transferred to the

roller sections

11,12 only in the two outer sections, where the anilox roller 7 has an axial overlap with the

roller sections

11, 12. Since the roller lining 13 has properties similar to those of the rubber blanket 6, the amount of fluid transferred per unit area by the anilox roller 7 to the

roller sections

11,12 in the outer zones is exactly equal to the amount of fluid transferred by the anilox roller 7 to the coating cylinder 5 in the intermediate zone between the outer zones. The fluid 31 removed from the outer section of the anilox roller 7 is transferred by the

roller press sections

11,12 onto the take-away roller 18 and taken away from the take-away roller 18 by the stripping blade 17 and conducted into the collection trough 16. The take-away roller 18 has a hard peripheral surface of metal or ceramic, and a peeling blade 17 is placed on the peripheral surface.

The axially overlapping sections of the anilox roller 7, the

respective roller sections

11 or 12 and the take-away roller 18 can be referred to as non-printing areas 15 and lie outside the format width of the print substrate 10 transported on the impression cylinder 4 during coating. If there is no countermeasure, a "border phenomenon" may occur in these non-printed areas 15 in such a manner that: where the fluid 31 is transferred by the anilox roller 7 onto the coating cylinder 5.

Although the arrangement of the blankets (Unterlagebogen) under the blanket 6 corresponding to the sheet format of the print substrate 10 can be a viable solution, this measure is very complex, since these blankets must be replaced with each format change, which is associated with a blanket removal and correspondingly long machine downtime.

In contrast to this, the removal device 19 is very advantageous in terms of operation, said removal device 19 comprising the

roller press sections

11,12, the take-away roller 18 and the stripping blade 17. The

roller sections

11,12 can be set manually, electromechanically or automatically to the desired specifications in the axial direction, but in all cases are carried out very quickly and are used to minimize machine downtime.

In the second embodiment according to fig. 4 and 5, the removal device 29 is configured as a suction device 28. The suction device 28 comprises a first suction section 21 and a second suction section 22 which rest on the anilox roller 7. These suction sections 21,22 are open towards the circumferential surface of the anilox roll 7 for drawing off fluid from the circumferential surface and from the anilox depressions (e.g. cups or grooves). These suction sections 21,22 do not extend over the entire length of the anilox roller 7 and overlap this anilox roller 7 only in the non-printing edge regions of the anilox roller 7 (i.e. not aligned with the printing region of the coating cylinder 5). The width of the non-printing edge regions and thus the spacing 20 (see fig. 3) therebetween can also be set adjustably in the second embodiment.

Depending on whether the set reduction or enlargement is to be set, the setting is set by moving the suction sections 21,22 toward or away from one another by means of a servomotor 23 via a threaded spindle 24. The threaded spindle 24 has a right thread and a left thread, wherein one thread is screwed into the first suction section 21 or into a nut fastened to the first suction section 21, and the other thread is screwed into the second suction section 22 or into a nut fastened to the second suction section 22. Instead of a screw drive comprising a threaded spindle 24, other drives can also be used to position the suction portions 21,22 according to the format width of the printing material. However, the screw drive has the advantage that it can also serve as a safety device as a functional unit for securing the suction portions 21,22 in the set position.

During the movement along the threaded spindle 24, the suction segments 21,22 are also each guided by linear guides, not shown together in the figures. The linear guide also prevents the suction segments 21,22 from rotating about the threaded screw. That is to say, the linear guides act as anti-rotation means (drehsichherung) for the suction sections 21, 22.

These suction sections 21,22 are attached to a pump 26 (e.g. a vacuum pump) via a hose 25. The pump 26 is driven by a pump motor 27, and the pump 26 pumps fluid from these suction sections 21,22 via hoses 25 into the purge vessel, or back into the holding tank 8 for reuse.

List of reference numerals

1 printing machine

2 precoating equipment

3 ink jet device

4 pairs of pressing rollers

5 coating roller

6 rubber cloth

7 roller (anilox roller)

8 storage tank

9 measuring scraper

10 printing material

11 first roll-pressing section

12 second rolling section

13 roll liner

14 roll axes

15 non-printing area

16 collecting tank

17 peeling scraper

18 take away roller (Abnahmewalze)

19 removing device

20 at intervals of

21 first suction section

22 second suction section

23 Servo motor

24-thread lead screw

25 flexible pipe

26 Pump

27 pump motor

28 suction device

29 removing device

31 fluid

Claims

1. A printing press, comprising: -a device for coating a substrate (10) by means of a roller (7), and-a removal device for partially removing a fluid (31) from the roller (7), characterized in that the removal device has at least one section which can be set adjustably as a function of different specifications of the substrate (10), the at least one section comprising at least one nip section, each nip section having a roller lining (13) made of rubber, and the removal device has a take-away roller (18) on which a stripping blade (17) rests, wherein, if the specification width of the substrate (10) to be processed is smaller than the maximum specification width which can be processed in the printing press, the fluid (31) is removed from the roller (7) by means of the removal device in an outer section of the roller (7) which lies outside the specification width of the substrate (10) to be processed, in that the fluid (31) removed from the outer section of the roller (7) is transferred by the at least one roller pressing section onto the take-away roller (18) and taken away from the take-away roller (18) by the stripping blade (17).

2. A printing machine according to claim 1, wherein the roller (7) is an anilox roller.

3. Printing machine according to claim 1 or 2, wherein the at least one section is supported so as to be laterally adjustable into different positions according to different specifications of the printing material (10).

4. Printing machine according to claim 1 or 2, wherein the removal device (29) comprises a suction device (28) and the at least one section comprises at least one suction section.

5. Printing machine according to claim 1 or 2, wherein the removal device (29) has two roller press sections which are supported so as to be laterally adjustable respectively into different positions and adjustable towards or away from each other.

6. Printing machine according to claim 1 or 2, wherein the removal device (29) comprises a suction device (28) and the at least one section comprises two suction sections which are supported so as to be respectively adjustable laterally into different positions and toward or away from each other.

7. A printing machine according to claim 1 or 2, characterized in that the apparatus is a pre-coating apparatus (2) and that the apparatus is followed by an ink-jet apparatus (3).