EP1149695B1 - Dampening unit for a offset printing press - Google Patents

Abstract

A water dosing system for an offset printing press has the dosing roller (5) fitted with scrapers (15) before and after the contact zone (13) with the print cylinder, to flatten out any peaks created by the contact zone. Additional scrapers can be fitted to the rider rollers (9, 10). The scrapers are set near tangential and comprise elastic strips on adjustable mountings.

Description

The invention relates to a dampening system for an offset printing press, that with a plate cylinder carrying a printing form and an inking unit in functional connection is after the Preamble of the main claim.

[State of the art]

A dampening unit of this type is known from DE 34 16 845 A1, which essentially consists of a feed device for the Fountain solution, a device for dosing the dampening film and a dampening roller that covers the dampening film transmits to a plate cylinder. The dampening system is with an inking unit assigned to the plate cylinder coupled as well as operated separately. The dampening roller is to the plate cylinder with different peripheral speed operable, so that for example foreign particles eliminating wiping effect.

From DE 34 32 807 A1 a dampening system is known, which a ink-absorbing roller (rider roller) of the dampening roller in Has assigned contact. This ink-absorbing roller rotates with a different one to the plate cylinder Peripheral speed and is to the neighboring inking unit coupled or can be operated separately with the dampening roller.

The disadvantage here is that on the dampening roller Ink accumulates, which is returned to the dampening system or the supply of dampening solution to the plate cylinder is impaired. These impairments affect print quality on the substrate, for example in the form of Stenciling or cord strips (streaks).

Furthermore, from DE 36 38 460 A1 a dampening system with an in a scoop roller immersed in a dampening solution. A scraper is arranged adjacent to this scoop roller, around deposits, such as paint particles, on the outer surface to eliminate the scoop roller.

The disadvantage here is that abrasion occurs on the wiper that contaminates the dampening solution. With longer use can the soft elastic material with color particles add so that the cleaning effect on the roller surface subsides.

According to DE-A-29 48 486 are a inking and dampening unit for one Rotary printing machine known in which the deforming / tearing of color or color / dampening solution layers for the purpose of releasing the enclosed Dampening solution. The exposed dampening solution is then dried. to This working principle is solved by means of vibration devices or Ultrasound sources used.

OBJECT OF THE INVENTION

The invention is based on the object, a dampening to create the kind mentioned at the beginning that the Avoids disadvantages, which is a process stable Dampening solution supply to the plate cylinder allowed and the The risk of emulsification is noticeably reduced.

The object is achieved by the training features of the independent claim. Further training results itself from the dependent claims.

It was found that on the outer surface of a dampening agent-carrying and ink-accepting dampening unit roller after ink had been torn off (sheared off) in a contact zone, for example with an ink-guiding plate cylinder, there was no uniform ink distribution - viewed across the roller width. On this dampening unit roller there is an uneven surface topography of the ink, which is characterized by ink peaks or ink domes and ink valleys on the outer surface of the dampening agent-carrying and ink-accepting dampening unit roller.
For example, in the case of a dampening roller after the ink splitting (separation of the ink layer) in a contact zone with a plate cylinder by tearing off ink, especially when thread-like tearing off, there is no uniform color distribution across the width of the roller, but an uneven surface topography of, for example, the dampening roller from the plate cylinder , cleaved residual color.

A first advantage of the invention is based on the fact that at least one dampening roller after a contact point of dampening roller and plate cylinder at least one in Direction of rotation of this plating device downstream of the dampening roller to the outer surface of the dampening roller can be adjusted in parallel.

The plating device causes a change in shape (plastic Shaping) of the color tips or color crests and the color valleys within the surface structure on the dampening roller the color. The change in shape represents a micro-forming the surface structure of the color such change in shape of the surface structure of the color the color tips or color tips slide into the color valleys, i.e. take place within the color layer of the color structure Sliding processes that cause the plastic shape, so that an approximately flat surface topography of color in a defined layer thickness can be achieved.

Advantageous for plastic shaping with a plating device it is that the color has no shear (Shear or fragmentation effect) is subject to a shear effect again to an unwanted tearing off of color and thus leads to an uneven surface topography.

The relatively flat achieved by means of the plating device Surface topography of ink on a dampening roller improves the wetting behavior for the absorption of Fountain solution and causes a process-stable fountain solution supply to the plate cylinder is realizable. So that is also a more precise dampening solution dosing and this reduces the risk of emulsification. A reduced consumption of dampening solution is advantageous as well as additives such as alcohol.

With the use of at least one plating device on a dampening roller, the wetting behavior of the Improved roller with dampening solution.

Another advantage is that the invention Plating device is not limited to a dampening roller is. Rather, the arrangement of plating devices also with other dampening solutions that accept ink Rolling of a dampening system can be realized. Here is preferably at least one plating device each Dampening roller assigned. Alternatively, there are several Plating devices can be arranged to form a dampening roller.

Depending on the geometry of the dampening unit, there is also the possibility of saving dampening unit rollers.
Another advantage is based on the fact that the improved wetting of the dampening unit rollers enables a reduction in dampening solution additives, for example isopropanol, to be achieved.
The formation of paint mist is also noticeably reduced through the use of plating devices.

The plating device serves to create a relatively flat surface topography on the outer surface of an assigned ink-accepting and dampening agent-carrying dampening unit roller. In the area of the plating device, paint should not be torn off on the outer surface of the corresponding roller, since otherwise uneven surface topographies would arise.
The design of the plating device is not limited to one or more mechanical plating device (s) with one or more plating element (s). For example, in order to achieve a flat surface topography of the ink by means of a blowing device directed at a dampening unit roller, blowing air can be used on the outer surface of the ink-carrying dampening unit roller or an ultrasonic vibration system directed at the outer surface of the ink-carrying dampening unit roller.

[Examples]

Fig. 1

ein Offsetdruckwerk für den Nass-Offset,

Fig. 2

ein Feuchtwerk des Offsetdruckwerkes,

Fig. 3

ein Detail einer Feuchtauftragwalze.

The invention will be explained in more detail using an exemplary embodiment. The following schematically show:

Fig. 1

an offset printing unit for wet offset,

Fig. 2

a dampening unit of the offset printing unit,

Fig. 3

a detail of a dampening roller.

The offset printing unit of a sheet-fed rotary printing press exists essentially from an inking unit 3 with one to one Plate cylinder 1 leading single drum roller with inking rollers 11. The plate cylinder 1 is in a known manner with a Blanket cylinder 2 in functional connection and the plate cylinder 1 is in the direction of rotation in front of the inking unit 3 Upstream of dampening unit 4.

The dampening unit 4 consists of at least one of the plate cylinders 1 assigned dampening roller 5 and a dampening solution supply 12, which in a contact zone 13 dampening solution the dampening roller 5 feeds. In the present example consists of the dampening solution supply 12 in one Fountain solution 8 immersible, drivable dampening roller 6, the functional connection with a metering roller 7 is. The dampening roller 5 is used for dampening with the plate cylinder 1 in a contact zone 13 in functional connection. The plate cylinder 1 is colored and the Dampening roller 5 transfers dampening solution to the plate cylinder 1 in the contact zone 13 (plate cylinder 1 / dampening roller 5), 13 takes place simultaneously in this contact zone a color break or a color splitting or color back splitting. Color is transferred from the plate cylinder 1 to the dampening roller 5 transferred, which is an uneven surface topography having.

In a preferred embodiment, a first rider roller 9 is arranged downstream of the contact zone 13 (with the plate cylinder 1) in the direction of rotation, which in turn is in a functional connection in a contact zone 13 with the dampening roller 5.
In a further development, a second rider roller 10 is arranged downstream of the contact zone 13 with the first rider roller 9 in the direction of rotation, which in turn is functionally connected to the dampener roller 5 in a contact zone 13. Depending on the design of the dampening unit 4, there are further contact zones 13 between further dampening unit rollers. Thus, in a configuration according to the present example, a contact zone 13 is also present between the metering roller 7 and the dampening roller 6. In this configuration, if necessary, a plating device 15 can also be arranged on the lateral surface of the metering roller 7 in the direction of rotation of the metering roller 7 after the contact point 13.

At least one dampening roller 5 is assigned at least one plating device 15 in the direction of rotation after the contact zone 13 (plate cylinder 1 / dampening roller 5), in which ink has broken off or is split, adjusably adjoining the outer surface. The plating device 12 extends essentially parallel over a full roller width of the dampening roller 5.
In a further embodiment, a plating device 15 of the dampening roller 5 is additionally arranged to be adjustable in the direction of rotation after the contact zone 13 with the dampening solution supply 12 and before the contact zone 13 with the plate cylinder 1.

The plating device 15 is preferably in each case by means of a force F on the lateral surface of the assigned Damping roller 5 or dampening unit rollers 6,7,9,10 unemployable. By means of the plating device 15 is preferred a uniform surface pressure across the roller width the surface area of the dampening roller that guides the color or residual color 5 or the dampening unit rollers 6,7,9,10 can be applied.

In a preferred embodiment, the Dampening roller 5, the plating device 15 in its Direction tangent or secant to the surface the dampening roller 5 adjustable.

Such a plating device 15 is preferably by a extending across the width of the roller, in the direction of rotation of the Damping roller 5 or dampening unit rollers 6,7,9,10 preferably tangentially positive in their direction of rotation Plating element 17 formed, which in a holder 14 detachably received parallel to the lateral surface of the respective Dampening roller 5,6,7,9,10 extends. The bracket 14 of the plating element 17 is preferably in one in the frame arranged pivot 16 on both sides, preferably around the Axis of the pivot joint 16 pivoted, mounted.

In a preferred embodiment, the plating element is 17th or the plating device 15 by means of at least one frame-side supported, preferably adjustable compression spring in functional connection. In particular the plating element 17 is preferably loaded by a force F. Alternatives are instead of a compression spring, for example pneumatic workable cylinder or other force F generating agents can be used. Likewise, depending on the arrangement the plating element 17 by utilizing its own weight with the assigned dampening unit roller 5,6,7,9,10 in functional connection, without a shearing effect on the lateral surface or the residual color. In further training is the plating device 15 also with a minimal Distance to the outer surface of the dampening roller 5,6,7,9,10 arranged to achieve a flat surface topography.

The free end of the plating element 17 preferably ends on a surface normal N (tangent point or secant point) of the dampening roller 5 or the respective dampening roller 6, 7, 9, 10. The free end of the plating element 17 preferably ends in a tangent or secant shape on the outer surface of one of the dampening unit rollers 5, 6, 7, 9, 10 in a tangent or secant point.
In a further embodiment, the cladding element 17 leads tangentially in the direction of rotation of the dampening roller 5 slightly beyond its outer surface, wherein tearing off of paint is to be avoided.
In a further embodiment, the free end of the plating element 17 ends at a slight distance from the outer surface of the respective dampening roller 5, 6, 7, 9, 10.

In the present example, the one according to the invention is preferred Plating device 15 of at least the dampening roller 5 assigned adjacent, for example with an offset printing ink through the ink-carrying plate cylinder 1 in the Contact point 13 takes back split color (residual color). The plating device 15 is in the direction of rotation Moist application roller 5 after the contact zone 13 (plate cylinder 1 / dampening roller 5) and preferably before another Contact point 13 of dampening solution supply 12 and dampening roller 5 arranged tangentially in the direction of rotation. This plating device 15 levels the uneven Surface topography on the surface of the dampening roller 5 after the contact zone 13 of plate cylinder 1 and Dampening roller 5 cleaved residual ink before prefers the residual ink with that of the dampening solution supply 12 supplied dampening solution in contact zone 13 in contact comes.

This is already in the direction of rotation of the dampening roller 5 in front of the contact point 13 of dampening solution supply 12 and Moist application roller 5 a leveled topography of the split-back paint on the surface of the dampening roller 5 before and wetting with dampening solution is noticeable improved. The flat surface topography leads again at approximately the same conditions in the contact zone 13 when adding dampening solution.

In a further development, the dampening roller 5 is after the Contact point 13 of dampening solution supply 12 and dampening roller 5 and in front of the contact point 13 of the dampening roller 5 and plate cylinder 1 additionally a plating device 15, preferably in the direction of rotation, the dampening roller 5 arranged parallel to the lateral surface.

If the dampening unit 4 has at least one rider roller 9, then is this roller 9, preferably in the direction of rotation, the Rider roller 9 a plating device 15 parallel to the outer surface arranged arranged. Another is analogous to this Plating device 15 of a second rider roll 10, preferred adjustable in the direction of rotation parallel to the lateral surface arranged. The rider rollers 9, 10 are in the direction of rotation the dampening roller 5 before the dampening solution supply 12 arranged.

The described plating device 15 is preferably arranged in the same configuration on all rollers 5, 6, 7, 9, 10 of the dampening unit 4.
The use of a plating device 15 is thus not limited to a dampening roller 5. Rather, the arrangement of plating devices 15 on other rollers 6, 7, 9, 10 of the dampening unit 4 can also be implemented, so that in the direction of rotation of a dampening agent-carrying dampening unit roller 5, 6, 7, 9, 10 after a contact zone 13 in which paint or ink is torn off ink splitting has occurred, at least one plating device 15 can be adjusted in parallel to the outer surface of the dampening unit roller 5, 6, 7, 9, 10.

Furthermore, in the direction of rotation of the dampening unit roller 5, 6, 7, 9, 10, a plating device 15 is arranged parallel to the outer surface of the dampening unit roller 5, 6, 7, 9, 10 in front of a contact zone 13 in which paint is torn or splitted.
Likewise, in the direction of rotation of the corresponding dampening unit roller 5, 6, 7, 9, 10, the plating device 15 is arranged so as to be adjustable in its direction tangent-shaped or secant-shaped to the outer surface of the dampening unit roller 5, 6, 7, 9, 10.

The mode of operation is as follows: there is ink on the plate cylinder 1, which is split back in the contact zone 13 to the dampening roller 5 which supplies the dampening agent (ink tear off).
After the contact zone 13, the residual ink is present as an uneven surface topography in the form of ink peaks, ink tips and ink troughs on the outer surface of the dampening roller 5. In the direction of rotation of the dampening roller 5, the plating device 15 flattens the uneven surface topography of the cleaved ink (residual ink) resulting from the demolition before the fountain solution supply 12.
The dampening roller 5 now passes through the contact zone 13 of the dampening solution supply 12 in the direction of rotation. Since the roller contact in this contact zone 13 causes a new ink splitting (ink separation), it is preferable to have an additional plating device 15 after the dampening solution supply 12 and before the contact zone 13 with the plate cylinder 1 arranged adjustable in the direction of rotation of the dampening roller 5. In a further embodiment, a plating device 15 is additionally arranged in the direction of rotation of the dampening roller 5 in front of the fountain solution supply 12. This is particularly useful if at least one rider roller 9 and / or 10 is arranged in the direction of rotation of the dampening roller 5 in front of the contact point 13 of the dampening solution supply 12. In the contact point 13 of the respective rider roller 9, 10 there is also a paint break, so that in turn an uneven surface topography can occur, which should preferably be leveled before the fountain solution supply 12.

The plating device 15 is to the lateral surface of the respective Dampening unit roller 5, 6, 7, 9, 10 arranged on and off. For example, this is in the case of reverse operation (Reverse running) of the respective dampening roller 5,6,7,9,10 meaningful.

[REFERENCE LIST]

1

plate cylinder

2

Blanket cylinder

3

inking

4

dampening

5

Dampener roller

6

dampening ductor

7

metering

8th

Dampening solution container

9

First rider roll

10

Second rider roller

11

Inking roller

12

Dampening solution supply

13

contact zone

14

bracket

15

plating

16

swivel

17

plating member

F

force

N

surface normal

Claims (12)

1. Damping unit for an offset printing press, which is functionally connected to a plate cylinder bearing a printing plate and an inking unit and has at least one damping solution applicator roll and a damping solution feed, characterized in that, in the direction of rotation of a damping unit roll (5, 6, 7, 9, 10) which carries damping solution, after a contact zone (13) in which ink is torn off or ink splitting takes place, at least one flattening device (15) is arranged such that it can be set parallel against the circumferential surface of the damping unit roll (5, 6, 7, 9, 10), over the full roll width, and in that, by means of the flattening device (15), a shape change of the ink present on the damping unit roll (5, 6, 7, 9, 10) can be achieved, so that the result is a planar surface topography of the ink in a defined layer thickness.
2. Damping unit according to Claim 1, characterized in that, in the direction of rotation of the damping unit roll (5, 6, 7, 9, 10), before a contact zone (13) in which ink is torn off or ink splitting takes place, the flattening device (15) is arranged such that it can be set parallel against the circumferential surface of the damping unit roll (5, 6, 7, 9, 10).
3. Damping unit according to Claim 1, characterized in that, in the direction of rotation of the damping unit roll (5, 6, 7, 9, 10), the flattening device (15) is arranged such that it can be set against the circumferential surface of the damping unit roll (5, 6, 7, 9, 10 ) in the form of a tangent or in the form of a secant in terms of its direction.
4. Damping unit according to Claim 1, characterized in that the damping unit roll that carries damping solution is a damping solution applicator roll (5) and, after the contact zone (13) with the plate cylinder (1), in the direction of rotation of the damping solution applicator roll (5), the flattening device (15) is arranged such that it can be set against this damping solution applicator roll (5).
5. Damping unit according to Claim 1 and 4, characterized in that the flattening device (15) is arranged such that it can be set at least in relation to a rider roll (9, 10) that is functionally connected to the damping solution applicator roll (5) in a contact zone (13), and in that the rider roll (9, 10) is arranged before the damping solution feed (12) in the direction of rotation of the damping solution applicator roll (5).
6. Damping unit according to Claim 1 and 4, characterized in that the flattening device (15) of the damping solution applicator roll (5) is arranged such that it can be set on in the direction of rotation after the contact zone (13) with the damping solution feed (12) and before the contact zone (13) with the plate cylinder (1).
7. Damping unit according to Claim 1, characterized in that the flattening device (15) can be set against the circumferential surface of the damping unit roll (5, 6, 7, 9, 10) by means of a force (F).
8. Damping unit according to Claim 1, characterized in that, by means of the flattening device (15), a uniform surface pressure can be applied over the width of the damping unit roll (5, 6, 7, 9, 10).
9. Damping unit according to Claim 1, characterized in that, in the direction of rotation of the damping unit roll (5, 6, 7, 9, 10), the flattening device (15) has a flattening element (17) which extends over the entire roll width and is detachably arranged in a holder (14).
10. Damping unit according to Claim 1 and 9, characterized in that the holder (14) is mounted on both sides in a rotary joint (16) fixed to the frame.
11. Damping unit according to Claim 1 and 9, 10, characterized in that a free end of the flattening element (17) ends in the form of a tangent or in the form of a secant on the circumferential surface of a damping unit roll (5, 6, 7, 9, 10) in a tangent or secant point.
12. Damping unit according to Claim 1 and 9, 10, characterized in that a free end of the flattening element (17) ends at a slight distance from the circumferential surface of the damping unit roll (5, 6, 7, 9, 10).

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