WO2009103397A1

WO2009103397A1 - Method for inking a printing forme in a processing machine

Info

Publication number: WO2009103397A1
Application number: PCT/EP2009/000456
Authority: WO
Inventors: Peter Hummel; Robert Ortner; Jürgen Schölzig
Original assignee: Manroland Ag
Priority date: 2008-02-19
Filing date: 2009-01-24
Publication date: 2009-08-27
Also published as: DE102008009892B4; DE102008009892A1

Abstract

The invention relates to a method for inking a printing forme in a processing machine for stocks. The aim of the invention is to devise a method that especially allows ink to be metered in a stable manner in a universally usable inking unit while noticeably reducing the ghosting tendency. Said aim is achieved by using a processing machine comprising an inking unit, an optional dampening unit, and a plate/form cylinder that has the printing forme. The inking unit encompasses an ink metering and ink delivering device, at least one roller train, and inking rollers for inking the printing forme. The flow of ink is fed to a distribution roller on which the flow of ink is split into two partial flows of ink by means of two partial roller trains, the two partial flows of ink are fed to a front inking roller in the direction of rotation of the plate/form cylinder, the front, first partial flow of ink in the direction of rotation of the plate/form cylinder (1) is temporarily interrupted at a separation point (18) of the first partial roller train (12), the distribution roller (8) then feeds the flow of ink to the downstream, second partial flow of ink of the second partial roller train (13), and at least one ink transport roller (15) of the first partial roller train (12) is temporarily integrated into the second partial roller train (13).

Description

Process for coloring a printing form in a processing machine

The invention relates to a method for coloring a printing form in a processing machine for substrates according to the preamble of the independent claim.

From EP 0 280 957 A2 an inking unit for a printing unit in an offset printing machine is known. The printing unit comprises a plate cylinder having a printing plate, wherein a dampening unit can be assigned to the plate cylinder. The inking unit comprises a distributor roller arranged in the roller train for the ink feed and two sub-roller trains arranged in parallel downstream of this distributor roller. The ink stream is divided from the distributor roller by means of two partial roller trains in two partial color streams and the two partial color streams are fed to a front in the direction of rotation of the plate / forme inking roller for coloring the printing plate.

A method and a device for color guidance are known from DE 102 48 517 A1 or from EP 0 741 024 A2. Thereafter, an inking roller train comprises a distributor roller and two sub-roller trains arranged in parallel downstream of said distributor roller and each having at least one inking roller in contact with a printing plate. The partial rolling trains can be separated at at least one nip so that temporarily the ink stream can be supplied to at least one of the inking rollers via the first or the second partial drawing train. Such color flow separations can prevent a change in the ink layer thickness profile in ongoing inking at printing interruptions. After elimination of the print interruption, the rollers are re-set together at the start of printing, so that the original color flow is restored. The invention is based on the object to provide a method of the type mentioned above, which allows in particular a stable color guide in a universally applicable inking and noticeably reduces the tendency for stenciling.

The problem is solved by the training features of claim 1. Further developments will become apparent from the dependent claims.

As is known, the stenciling is an error phenomenon during printing, in which a structure of the printing form - offset in the printing direction - one or more times additionally images.

A first advantage of the solution according to the invention therefore lies in the fact that, especially in the case of difficult printing plates and / or special printing inks, such as metallic inks or inks that absorb excessively dampening solution, these irregularities when coloring a printing forme are avoided or at least noticeably reduced.

A second advantage is due to the fact that, starting from a distributor roller arranged in the roller train of an inking unit, the color flow in the printing operation or the planned ink flow is already influenced in a targeted manner even before the start of printing (in the case of machine standstill). For this purpose, in the inking unit, the amount of ink (color flow) supplied in the direction of the printing form can be supplied in variable ink flow proportions to the respective inking rollers. Thus, color flow components can be realized, which result in different working methods of the inking unit, a different load distribution of the ink flow in the inking unit. The inking unit is universally applicable for a variety of Drucksujets, responsive and the existing inking rollers remain preferred - despite different switching positions - always in the respective color flow.

Starting from the distributor roller, the ink flow to a front-heavy designed inking unit, ie at least in the direction of rotation of the plate / forme cylinder first and preferably second, optionally third inking roller are supplied with a relatively high ink flow rate and the remaining reduced ink flow rate is the other, for example, third and fourth and optionally further, inking rollers supplied.

Alternatively, from the distributor roller, the ink flow to a medium-duty inking unit, i. to the in the direction of rotation of the plate / forme cylinder at least second and preferably third inking roller are supplied with a relatively high ink flow rate and the remaining reduced ink flow rate is the other, for example, first and fourth and optionally further, inking rollers supplied.

It is also advantageous that, in the event of a possible occurrence of stenciling phenomena during printing, the inking unit can be selectively operated by switching operations of the ink transport rollers downstream of a distributor roller in a first and second partial roller train, if necessary also inking rollers, the inking unit can be operated in universal working methods. Thus, possible stencilling phenomena are avoidable or at least significantly reducible with a simultaneously stabilized color guide. In this case, the changeover of the ink flow from the distributor roller can be carried out in accordance with the respective mode of operation during machine standstill and during the printing operation.

The invention will be explained in more detail using an exemplary embodiment. Here are shown schematically:

1 is an inking unit of an offset printing machine,

2 the inking unit in a first embodiment,

Fig. 3, the inking unit in a second embodiment. According to FIG. 1, an inking unit for an offset printing press is shown which, inter alia, comprises a dye metering / feeding device 10. This ink metering / feeding device 10 can preferably be formed by a paint box with metering device and with ink fountain roller and a dye fountain roller or a film inking roller. The ink fountain roller or the film inking roller is preferably in operative connection with a fourth inking roller 9. The fourth inking roller 9 is followed by at least one compactor 11 having a plurality of ink transfer rollers in the color flow direction, which form a first color flow. This first color flow is transferred to a, one of the ink transfer rollers downstream distributor roller 8, which distributor roller 8 may preferably be formed as a third inking roller 8.

Viewed in the direction of color flow, the further compactor splits at the distributor roller 8 and thus the color flow over two subordinate, designed as branch rollers ink transfer rollers 15, 16 into a first and a second partial roller train 12, 13 and thus the color flow divided into two partial color streams. Each of the sub-roller trains 12, 13 may include a plurality of ink-transfer rollers as needed. The two partial ink streams are fed to a front in the direction of rotation of the plate / forme cylinder 1 inking roller, here a second inking roller 3.

In the present example, the first partial roller train 12 in the direction of rotation of a plate / forme cylinder 1 is formed by the ink transport roller 15, which is designed as a first branch conveyor, and a first inking roller 6 arranged downstream of this. About the ink transfer roller 15, the first part of color flow on the first Farbrei- berwalze 6 and seen in the direction of rotation of the plate / forme cylinder 1 subsequent front (first two) inking rollers 2, 3 of the inking unit supplied.

Furthermore, the second partial roller train 13 in the direction of rotation of the plate / forme cylinder 1 is formed by the ink transport roller 16 designed as a second branch roller and a color transport roller 17 arranged downstream of it. The color transport Roller 17 is as a bridge roller with the front, second inking roller 3 and a downstream in the direction of rotation of the plate / forme cylinder 1, third inking roller 4 in contact. The third inking roller 4 is followed by a fourth inking roller 5 in the direction of rotation of the plate / forme cylinder 1, with both inking rollers 4, 5 being bridged by a second inking roller 7. Via the ink transfer roller 16, the second partial ink flow is thus supplied to the two inking rollers 3, 4 via the ink transfer roller 17. From the third inking roller 4 7 ink on the fourth inking roller 5 is fed via the second ink fountain roller.

From the inking rollers 2 to 5, the color is supplied to the plate / forme cylinder 1. The plate / form cylinder 1 carries a fixable on the lateral surface printing plate, for example as a printing plate or sleeve. Alternatively, a printing form can be produced, fixed and preferably erased on the lateral surface of the plate / forme cylinder 1.

All Farbreiberwalzen 6 to 9 are rotationally and / or axially iridescent drivable. All inking rollers 2 to 5 are driven by friction and are formed on / off adjustable. If necessary, the inking rollers 2 to 5 may be formed axially iridescent, the traversing movement is also settable. The first, third and fourth inking rollers 2, 4 and 5, if necessary, individually, in groups or in total smoothing rollers 19 are assigned directly.

For wet offset printing, a dampening unit 14 may be arranged upstream of the inking unit 14 in the direction of rotation of the plate / forme cylinder 1.

Starting from the basic design shown in FIG. 1, depending on the print job and / or the rheological conditions, the first partial roller train (first partial ink flow) 12 in the direction of rotation of the plate / forme cylinder 1 is temporarily interrupted at a separation point 18. Thereafter, from the distributor roller 8, this first partial ink flow is fed to the second partial roller train (second partial ink flow) 13 arranged downstream in the direction of rotation of the plate / forme cylinder 1. For this purpose, at least one ink feed roller, here the ink feed roller 15, from the first Partial color flow temporarily integrated into the second partial color flow.

In an embodiment according to FIG. 2, the ink transfer roller 15 can be temporarily brought into contact with the distributor roller 8 and the ink transfer roller 17 of the second partial roller supply (second partial ink flow) 13.

In this embodiment, the first partial color flow is integrated into the second partial color flow. This results in a design of the ink flow components on the second and third inking rollers 3 and 4 of a total of approximately 70%. The first inking roller 2 has a reduced ink flow component and the fourth inking roller 5 has the lowest ink flow component.

In a further embodiment of Fig. 3, the ink transfer roller 15 can be temporarily brought into contact with the ink transfer roller 17 of the second Teilwalzenzuges (second partial ink stream) 13 and the first inking roller 6 of the first Teilwalzenzuges 12 (first partial color flow), wherein the ink transport roller 15 with the distributor roller 8 is out of contact.

In this embodiment, the first partial ink flow is separated directly at the distributor roller 8 (separation point 18) and the ink transfer roller 15 is in contact with the ink transport roller 17 of the second partial color flow and the first ink roller 6 of the first partial color flow. This results in a design of the ink flow components on the second and third inking rollers 3 and 4 of a total of approximately 70%. Although the first inking roller 2 has a reduced, but with respect to the embodiment of FIG. 2 higher ink flow rate and the fourth inking roller 5 has the lowest ink flow rate.

After completion of the print job, alternatively in the printing operation, the color flow can be switched to the basic version of FIG. LIST OF REFERENCE NUMBERS

1 platter / forrn cylinder

2 first inking roller

3 second inking roller

4 third inking roller

5 fourth inking roller

6 first inking roller

7 second ink roller

8 distributor roller (third ink roller)

9 fourth inking roller

10 paint dosing / feeding

11 compactor (first color flow)

12 first partial roller train (first partial color flow)

13 second partial roller train (second partial color flow)

14 dampening unit

15 ink transfer roller (first branch roller)

16 ink transfer roller (second branch roller)

17 ink transfer roller

18 separation point (first partial color flow)

19 smoothing roll

Claims

claims

1. A method for coloring a printing form in a processing machine for substrates, with an inking unit and optionally a dampening unit and a printing plate having plate / forme cylinder, wherein the inking unit comprises a Farbdosier- and Farbzuführeinrichtung, at least one compactor and inking rollers for inking the printing form and the ink stream is fed to a distributor roller, is split at the distributor roller by means of two sub-roller trains in two sub-color streams and the two sub-color streams are fed to a front in the direction of rotation of the plate / forme inking roller, characterized in that in the direction of rotation of the plate / forme cylinder (1 ) first, first partial ink flow temporarily at a separation point (18) of the first part roller train (12) is interrupted and then from the distributor roller (8) of the ink stream in the direction of rotation of the plate / forme cylinder (1) downstream, second partial ink flow of the second part roller train ( 13) is supplied and that at least one ink transfer roller (15) from the first partial ink stream is temporarily integrated into the second partial ink stream.

2. The method according to claim 1, characterized in that the ink transfer roller (15) is temporarily brought into contact with the distributor roller (8) and a color transfer roller (17) of the second partial color flow.

3. The method according to claim 1, characterized in that the ink transport roller (15) is temporarily brought into contact with a ink transfer roller (17) of the second partial ink stream and a first inking roller (6) of the first partial ink stream, wherein the ink transfer roller (15) with the distributor roller (8) is out of contact.