GB2324270A

GB2324270A - Inking unit for a rotary printing press

Info

Publication number: GB2324270A
Application number: GB9808026A
Authority: GB
Inventors: Peter Hummel; Robert Ortner; Marc Hinz
Original assignee: MAN Roland Druckmaschinen AG
Current assignee: Manroland AG
Priority date: 1997-04-15
Filing date: 1998-04-15
Publication date: 1998-10-21
Anticipated expiration: 2018-04-15
Also published as: FR2761925A1; DE19715614B4; GB2324270B; FR2761925B1; GB9808026D0; DE19715614A1

Abstract

An inking unit for a rotary printing press has a vibrator roller (3) moving to and fro transferring ink from a ductor roller (1) to a first transfer roller (4) and a second transfer roller (6) which is a part of an ink-transferring connection between the first transfer roller (4) and an ink applicator roller (9) applying the ink to a plate cylinder (10). The first transfer roller (4) is driven by a first motor drive, and the second transfer roller (6) in common with the plate cylinder (10) by a second independent motor drive. Between the first transfer roller (4) and the second transfer roller (6), freely rotatable intermediate rollers (5) are arranged which are in frictional contact with the transfer rollers (4, 6) which transfer the ink from the first transfer roller (4) to the second transfer roller (6).

Description

2324270 INKING UNIT FOR A ROTARY PRINTING PRESS This invention relates to

an inking unit for a rotary printing press of the type in which a vibrator roller is arranged to transfer ink from a ductor roller on to a first transfer roller, the vibration roller being movable to and fro between a first position in which it is contact with the ductor roller and a second position in which it is lifted away from the ductor roller and is in contact with the first transfer roller. The inking unit also contains a second transfer roller which is part of the ink-transferring in connection between the first transfer roller and an ink applicator roller which applies the ink to a plate cylinder. In such an arrangement, the first transfer roller is driven by a first motor drive, the second transfer roller, in common with the plate cylinder, from a second independent motor drive and the ductor roller by a third independent motor drive.

In an inking unit of this type known from European Published Specification 0 475 120 Al, the independent drive of the first transfer roller separated from the drive of the plate cylinder should prevent that the so- called vibrator impact, which, on the impact of the relatively slowly moving surface of the vibrator roller with the more rapidly moving surface of the transfer roller generates a rotational oscillation which is transferred to the turning plate cylinder and thereby adversely affects the transfer of the inked printed image from the plate cylinder. In this known inking unit, the surfaces of the first and second transfer rollers are in direct ink-transferring contact with one another with the result that, despite the independent drives of both transfer rollers, strong oscillations generated by the vibrator impact are transferred and can lead to an adverse effect on the rotating plate cylinder. In order to diminish the extent of rotational oscillation, it is further provided in the known inking unit that the vibrator roller is driven from the first transfer roller and simultaneously subjected to a controlled slip with reference to the first transfer roller.

The present invention aims to improve the damping of the rotational oscillations generated by the vibrator impact in an inking unit of the initially noted type, and to avoid transfer of the oscillations to the plate cylinder.

This is achieved by providing, in an inking unit of the type set out above, between the first and the second transfer roller, at least one freely rotatable intermediate roller which stands in frictional contact with the first and second transfer rollers and which transfers the ink from the first to the second transfer roller.

It has emerged that by means of such an arrangement of an intermediate roller, the rotational movement of which is 3 - determined explicitly by frictional contact with both the transfer rollers, a surprisingly effective damping of the rotational oscillations generated by the vibrator roller can be achieved. The damping can be further increased if between the transfer rollers, a roller train of two or even three rotatable intermediate rollers is arranged.

According further to the invention, the to and fro movement of the vibrator roller may be generated by the second motor drive and the first motor drive may be provided with a device for rotational speed control enabling the rotational speed of the first motor drive to be controlled so that the peripheral speed of the first transfer roller is the same as the peripheral speed of the plate cylinder. By means of this, it is achieved that the movement of the vibrator roller in customary fashion can result from the press drive, wherein by the synchronisation of the course of movement between vibrator roller and transfer roller, it is guaranteed that the number of over-rollings of the vibrator roller against the transfer roller is the same at differing press speeds and accordingly also always the same quantity of ink is fed into the inking unit.

The invention is explained in more detail below with reference to an exemplary embodiment which is illustrated in the accompanying schematic drawing of a roller inking unit of an offset rotary printing press, in side view.

In the roller inking unit illustrated, ink is applied in the form of a defined ink film from an ink storage container 2 on to the surface of a ductor roller 1. A vibrator roller 3, which is movable to and fro between the ductor roller 1 and a first transfer roller 4, takes - 4 ink from the ductor roller 1 and transfers this metered to the transfer roller 4. Three intermediate rollers 5 transport the ink from the transfer roller 4 to a second transfer roller 6. From there, the ink arrives via further transfer rollers 7 and 8 on to several ink applicator rollers 9 which feed the now finely distributed ink on to the plate cylinder 10 in order to ink up the printed image located on this. A blanket cylinder 11 transfers the inked printed image to a not illustrated material to be printed.

Arranged relative to the plate cylinder 10 is a damping unit including a damping agent container 12, a damping ductor 13, a metering roller 14 and a damping applicator roller 15 to apply a damping film to the plate on plate cylinder 10.

The transfer rollers 4, 6, 8 of the inking unit are constructed as distributor rollers which can be moved to and fro axially and which are driven by a motor drive with the same peripheral speed as the plate cylinder 10. The vibrator roller 3, the intermediate rollers 5, the transfer rollers 7 and the applicator rollers 9 are mounted freely rotatably. There drive results in each case by frictional contact with the rotating driven rollers 4, 6, 8 or with the plate cylinder 10. The drive of the transfer roller 4 takes place via a first independent drive motor, the rotational speed of which is controlled in such a fashion that the peripheral speed of the transfer roller 4 is in each case the same as the peripheral speed of the plate cylinder 10. The transfer rollers 6, 8 and the plate cylinder 10 are driven in common from a second independent drive motor via a power divider with the same peripheral speed. A third independent drive motor serves for driving the ductor roller 1, wherein the peripheral speed of the ductor roller 1 however is smaller than the peripheral speed of the plate cylinder 10 and accordingly also of the transfer roller 4.

In operation, the vibrator roller 3 is set by a to and fro movement of its rotational axis in the radial direction either against the ductor roller 1 in order to pick up ink from this, or against the transfer roller 4 in order to transfer ink to this. In this connection, the vibrator roller 3 is driven in each case in accordance with its position either by surface contact with the ductor roller 1, or the surface contact with the is transfer roller 4, wherein its peripheral speed changes in each case and is matched to the peripheral speed of the respectively driven roller. On impact of the vibrator roller 3 on to the transfer roller 4, the vibrator roller 3 coming from the slower turning ductor roller 1 is in each case strongly accelerated, wherein, as a result of the impact, rotational oscillations arise, which should not be transferred to the plate cylinder 10. The transfer of these rotational oscillations works counter to the independent motor drive of the transfer roller 4. It has, however, emerged that this measure alone is not sufficient since also via the frictional contact of the rollers, rotational oscillations are transferred. In order here to achieve an effective damping of the rotational oscillation and also substantially to suppress the oscillation transfer via frictional contact, between the transfer rollers 4 and 6 driven independently from one another, three intermediate rollers 5 are arranged which are mounted freely rotatably. The freely oscillating rotating masses of the intermediate rollers 5 and the contact positions allowing a little bit of slip, which connect the intermediate rollers with one another and in frictional fashion with the transfer rollers 4, 6, provide for an effective damping even of stronger rotational oscillations and prevent a transfer of the oscillations on to the transfer roller 6 and the plate cylinder 10 connected rotationally fast with this via a gear.

Claims

1. An inking unit for a rotary printing press, the unit including a vibrator roller adapted to transfer ink from a ductor roller to a first transfer roller, the vibrator roller being movable to and fro between a first position in which it is in contact with the ductor roller and a second position in which it is lifted from the ductor roller and in contact with the first transfer roller, and the unit including a second transfer roller which is part of an ink- transferring connection between the first transfer roller and an ink applicator roller applying the ink to a plate cylinder, wherein the first transfer roller is driven by a first motor drive, the second transfer roller is driven in common with the plate cylinder by a second independent motor drive and the ductor roller is driven by a third independent motor drive, and wherein between the first transfer roller and the second transfer roller, there is arranged at least one freely rotatable intermediate roller which may be brought alternately into frictional contact with the transfer rollers to transfer ink from the first transfer roller to the second transfer roller.

2. An inking unit according to Claim 1 wherein the to and fro movement of the vibrator roller is generated by the second motor drive and the first motor drive has a device for controlling its rotational speed to control the peripheral speed of the first transfer roller to the same as the peripheral speed of the plate cylinder.

3. An inking unit substantially as hereinbefore described with reference to the accompanying drawing.

1

4. A rotary printing press including an inking unit according to any one of Claims 1 to 3.