EP1698463B1 - Damping device for an offset printing unit of a printing machine - Google Patents

Description

The invention relates to a dampening unit with an offset printing unit of a printing machine, wherein the offset printing unit comprises an inking unit and a plate cylinder carrying a printing plate with associated blanket cylinder, according to the preamble of claim 1.

A dampening unit of this kind is out DE 30 16 366 A1 which comprises a drivable moisturizer immersed in a fountain solution container and a dampening applicator roller directly in contact with the dampening ductor. The dampening roller is further engageable with a plate cylinder carrying a printing plate. In order to improve the dampening solution guide, a hydrophobic distribution cylinder which is in contact with the dampening applicator roll and which compares the dampening residue profile in the direction of rotation of the dampening applicator roll is arranged after the point of contact with the plate cylinder as a rider roll. In a development of the dampening form roller is a single arranged metering roll, in the direction of rotation of the dampening form roller before the contact point with the plate cylinder, adjustable.

According to DE 34 16 845 A1 a dampening unit essentially consists of a feeder for the dampening solution, a device for metering the dampening solution film and an applicator roller which transmits the dampening solution film to a plate cylinder carrying the printing plate and coupled to the adjacent inking unit or can also be operated separately. The dampening roller can have a different peripheral speed to the plate cylinder, so that, for example, foreign particles eliminating wiping effect arises.

From the DE 3432 807 A1 in conjunction with the U.S. Patent 4,724,764 is a continuing dampening known. In addition to optionally different peripheral speeds of plate cylinder and dampening roller a ink-absorbing roller is assigned as a so-called rider roll of the dampening form roller. The ink-absorbing roller rotates with a different speed to the plate cylinder peripheral speed and can with a coupled adjacent inking or operated separately from this.

A disadvantage of these embodiments is that the ink accumulating on the dampening roller is fed into the dampening unit and thus the color / dampening solution balance is impaired. These impairments show up in the form of stenciling or kordstreifen (streaks).

Out EP-A-1 561 578 a method for transporting dampening solution is known, wherein the dampening solution is fed via three juxtaposed rollers a form cylinder of a printing press. The first and second rollers are coupled to a separate drive.

The greater the surface speed of the forme cylinder, the closer the surface speed of the second roller to that of the forme cylinder is brought.

WO 2004/054804 A describes a dampening unit with a fountain solution from a reservoir receiving a first roller and a second roller, which are part of a compactor. The first and the second roller have separate drives, wherein the two rollers differ in their surface speeds on the drive side.

According to EP-A-0 764 524 is a short inking unit for an offset printing machine known. In the direction of rotation of the forme cylinder, this is preceded by a dampening unit. The structure of the dampening unit is not described in detail. In the drawings, only a dampening roller and a further upstream roller are visible, the latter roller is adjacent to another component.

In DE 195 01 146 C1 a dampening unit is known with a rolling on the forme dampening form roller, which is arranged upstream of a transfer roller. The transfer roller is in operative connection with a dampening agent metering device. Between the dampening roller and the transfer roller two parallel arranged and standing in direct contact with two rollers bridge rollers are arranged.

Another dampening unit is out DE 36 44 982 A which comprises a feed strand for dampening solution, formed by a drivable moisturizer immersed in the dampening solution container and a dampening applicator roll which can be brought into direct contact with the dampening roller and the plate cylinder. The dampening roller is directly a bridge roller to the inking and below the dampening roller arranged a dampening.

Out EP-A-0 478 493 For example, a dampening system is known, which comprises a dampening solution container with a dampening duct, a transfer roller and a dampening roller. The dampening roller can be brought into contact with the plate cylinder or a bridge roller. A drive device is coupled to the dampening duct and the transfer roller.

A drive of a dampening unit is off DE 39 23 350 C1 known. The dampening unit comprises a feed strand for dampening solution, formed by a dampening roller immersed in a storage container and a dampening applicator roller directly contacting the dampening roller and the plate cylinder. The dampening roller is assigned a metering roller. In order to drive the dosing roller of the dampening ductor without circumferential slippage during the common washing of dampening and inking unit, the toothed wheel drive causing the circumferential slipping is separated or separated around the axis of the dampening duct by means of separating or restoring the tooth engagement of two idler gears by pivoting a lever carrying the dosing roller and an intermediate gear engageable.

The object of the invention is to provide a dampening unit of the type mentioned, which noticeably improves the print quality by a more uniform, trouble-free dampening solution to the plate cylinder.
The problem is solved by the training features of claim 1. Further developments will become apparent from the dependent claims.

An advantage of the invention is that in a dampening unit - starting from a feed strand formed at least from dampening ductor and a dampening form roller in contact with it - the dampening solution supply from the dampening ductor to the dampening form roller can be realized via at least one second feed strand formed from rolls. In a further embodiment, in addition to the second feed strand, a third feed strand formed from rolls can realize the dampening solution feed from the dampening roller to the dampening form roller.

Another advantage is given by the fact that with the formation of the present invention, a reduction of dampening solution excess due to the channel passage of the plate cylinder on the dampening form roller achievable and a more uniform, the print quality improving dampening solution distribution on the dampening form roller can be realized. Furthermore, stenciling (defects in which the print subject splits one or more times on the dampening form roller) and / or streaking (cord strip) on the dampening form roller is counteracted.

A further advantage is that the dampening unit according to the invention reduces the speed of the dampening duct and also reduces the use of alcohol. The roller arrangement ensures a rapid achievement of the color / dampening solution balance when producing a very thin wet film. If required, at least the second feed strand may additionally be assigned a metering roll which is in contact with the moisturizer.

Fig. 1

ein Feuchtwerk mit zwei Zuführsträngen für Feuchtmittel zur Feuchtauftragwalze,

Fig. 2

ein Feuchtwerk gemäß Fig. 1 mit einem zusätzlichen, dritten Zuführstrang.

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

Fig. 1

a dampening unit with two supply lines for dampening solution to dampening roller,

Fig. 2

a dampening unit according to Fig. 1 with an additional, third feed line.

An offset printing unit of a printing press comprises at least one plate cylinder 1 carrying a printing plate and a blanket cylinder 2, the plate cylinder 1 being in operative connection with an inking unit 3 and a dampening unit 4. The inking unit 3 associated with the plate cylinder 1 consists of a plurality of inking rollers 11, which are connected to ink-feeding rollers (not shown). The dampening unit 4 is - viewed in the direction of rotation of the plate cylinder 1 - upstream of the inking unit 3 and consists in the present example of a fountain solution 8, a dipping into the fountain solution 8, rotatably drivable Feuchtduktor 6, if necessary, a Feuchtduktor 6 in contact associated metering roller 7 and a dampening roller 5. Feuchtduktor 6 and dampening roller 5 are in contact and form a first Zuführstrang for dampening solution to the plate cylinder 1, wherein the dampening form roller 5 can be brought into contact with the plate cylinder 1 in a contact point 15. If necessary, the dampening duct 6 is coupled to an axially distributing traversing drive. Preferably, the dampening roller 5 is in the direction of rotation after the contact point 15 associated with a bridge roller 12 brought into contact, which can be brought into contact with the first in the direction of rotation of the plate cylinder 1 inking roller 11 of the inking unit 3.

In addition to the first feed line for dampening solution, formed by dampening roller 6 and dampening roller 5, the dampening unit 4 comprises a further supply line for fountain solution, which consists of with the dampening roller 6 and the dampening roller 5 in contact rollers (first transfer roller 10 and first rider roller 9 or second Transfer roller 14 and second rider roller 13).

In a first embodiment of the additional Zuführstrang is a with the Moisture ductor 6 in contact first transfer roller 10 and one with the first transfer roller 10 and the dampening roller 5 in contact, in the direction of rotation of the dampening roller 5 after the contact point 15 of plate cylinder 1 and dampening roller 5, arranged first rider roller 9 is formed.

In a second embodiment of the additional Zuführstrang from a standing with the dampening roller 6 in contact second transfer roller 14 and a second transfer roller 14 and the dampening roller 5 in contact, in the direction of rotation of the dampening roller 5 in front of a contact point 15 of plate cylinder 1 and dampening roller. 5 , arranged second rider roll 13 is formed.

In a third embodiment of the additional Zuführstrang from the standing with the dampening 6 in contact first transfer roller 10 and the first transfer roller 10 and the dampening roller 5 in contact, in the direction of rotation of the dampening roller 5 after the contact point 15 of plate cylinder 1 and dampening roller 5, arranged first rider roll 9 and in combination of the second transfer roller 14 in contact with the dampening roller 6 and the second transfer roller 14 and the dampening roller 5 in contact, in the direction of rotation of the dampening roller 5 in front of the contact point 15 of plate cylinder 1 and dampening roller 5, arranged second rider roll 13 is formed.

In a preferred embodiment, the dampening duct 6 is driven separately rotatably. Preferably, the dampening duct 6 is coupled to an axially traversing traversing drive. The dampening roller 5 is drivable by means of a separate, controllable drive or with a machine drive, for example coupled to the plate cylinder 1. Alternatively, the rotational drive of the dampening form roller 5 can be made non-positively.

In a further development, the first rider roll 9 is coupled to a rotary drive and / or an axially traversing traverse drive. Preferably, the first rider roll 9 with the same or unequal peripheral speed to the dampening form roller 5 is operable. Alternatively, the rotational drive of the first rider roller 9 can be made non-positively.
In a development, the first transfer roller 10 is coupled to a rotary drive and / or an axially distributing traversing drive. Preferably, the first transfer roller 10 with the same or unequal peripheral speed to the dampening duct 6 operable. In a development, the second rider roll 13 is coupled to a rotary drive and / or an axially distributing traversing drive. Preferably, the second rider roll 13 with the same or unequal peripheral speed to the dampening form roller 5 is operable. Alternatively, the rotational drive of the second rider roll 13 can be made non-positively.

In a further development, the second transfer roller 14 is coupled to a rotary drive and / or an axially distributing traversing drive. Preferably, the second transfer roller 14 with the same or unequal peripheral speed to the dampening duct 6 is operable.

The surface of the dampening form roller 5 is preferably made of a fountain solution friendly rubber material, including a compressible rubber material. The surface of the rider rolls 9, 13 may be designed friendly for dampening solution or printing ink. Possible materials are polyamide, stainless steel, chrome surfaces, ceramics.

The mode of action of the dampening unit 4 is as follows: In the printing operation, dampening solution is drawn from the dampening solution container 8 in a known manner by the dampening ductor 6 and transferred to the dampening applicator roll 5 in the contact point. From the dampening roller 5 of the dampening solution film is transferred in the contact point 15 to the plate cylinder 1 and the printing plate. If necessary, the moisturizer 6 is associated with a metering roller 7 in contact, which meters the fountain solution located on the dampening 6 in the contact point. Preferably, the metering roller 7 is in its axial position to the axis of the dampening duct 6 from an axially parallel position in an obliquely adjustable position and back adjustable, i. the relative position of the axis of the metering roller 7 is the axis position of the dampening ductor 6 cutting or axially adjustable. This obliquely adjustable axial position of the metering roller 7 improves the metering result, in particular for a metering roller 7 for larger format widths. Alternatively, the axial position of the metering roller 7 can be arranged generally obliquely to the axis of the Feuchtduktors 6.

Starting from the dampening duct 6 is formed by an additional roll of feed consisting of the first transfer roller 10 and the first rider roll 9 or the second transfer roller 14 and the second Rider roller 13, fountain solution supplied to the dampening roller 5. In a further development, the additional feed strand consists of a combination, namely the first transfer roller 10 in contact with the dampening roller 6 and the first rider roller 9 in contact with the first transfer roller 10 and the dampening applicator roller 5 and the second roller in contact with the dampening roller 6 Transfer roller 14 and arranged with the second transfer roller 14 and the dampening roller 5 in contact second rider roller 13. The dampening roller 5 is thus supplied via an additional Zuführstrang or according to the Weiterbildüng two additional feed strands fountain solution.

If necessary, for example, when washing the dampening unit, a separation can take place in the contact point of dampening roller 5 and dampening ductor 6. Preferably, at least the first transfer roller 10 and - in the presence - the second transfer roller 14 to the dampening duct 6 arranged separable. In a preferred embodiment, the first rider roll 9, the first transfer roll 10, the second rider roll 13 and the second transfer roll 14 are arranged individually or in pairs to the dampening form roller 5 and to the dampening duct 6 at // abstellbar.

By the number of cleavage sites (contact points) and / or the axial trituration and / or the type of peripheral speeds and / or the choice of the roll surfaces a uniform dampening solution distribution on the dampening form roller 5 is achieved. As a result, the print quality is noticeably improved, there are no streaks or stencils or are noticeably reduced, there is no build-up of ink on the dampening roller 5 or this is noticeably reduced and ultimately the channel strip initiated by the channel passage of the plate cylinder 1 is noticeable reduced.

REFERENCE NUMBERS

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

first transfer roller

11

Inking roller

12

bridge roller

13

second rider roll

14

second transfer roller

15

contact point

Claims (16)

1. A dampening unit (4) with an offset printing unit of a printing press, wherein the offset printing unit comprises an inking unit (3) and a plate cylinder (1) carrying a print form with associated blanket cylinder (2) and in that the dampening unit (4) comprises a feeding line for dampening solution formed by a rotatorically drivable dampening fountain roller (6) dipping into a dampening solution container (8) and a dampening form roller (5) that can be brought into direct contact with the dampening fountain roller (6) and the plate cylinder (1), characterized in that the dampening unit (4) comprises an additional feeding line for dampening solution that is in contact with the dampening fountain roller (6) and with the dampening form roller (5) consisting of rollers (10, 9 or 14, 13).
2. The dampening unit according to Claim 1, characterized in that the additional feeding line of a first transfer roller (10) being in contact with the dampening fountain roller (6) and a first rider roller (9) that is in contact with the first transfer roller (10) and the dampening form roller (5) being arranged after a contact point (15) of plate cylinder (1) and (5).
3. The dampening unit according to Claim 1, characterized in that the additional feeding line is formed of a second transfer roller (14) in contact with the dampening fountain roller (6) and a second rider roller (13) that is in contact with the second transfer roller (14) and the dampening form roller (5), and arranged in direction of rotation of the dampening form roller (5) in front of a contact point (15) of plate cylinder (1) and (5).
4. The dampening unit according to Claim 1, characterized in that the additional feeding line is formed of a first transfer roller (10) being in contact with the dampening fountain roller (6) and a first rider roller (9) being in contact with the first transfer roller (10) and the dampening form roller (5), being arranged in direction of rotation of the dampening form roller (5) after a contact point (15) of plate cylinder (1) and (5), and of a second transfer roller (14) being in contact with the dampening fountain roller (6) and a second rider roller (13) being in contact with the second transfer roller (14) and the dampening form roller (5), being arranged in direction of rotation of the dampening form roller (5) in front of a contact point (15) of plate cylinder (1) and (5).
5. The dampening unit according to any one of the preceding claims, characterized in that the dampening fountain roller (6) is coupled to an axially oscillating drive.
6. The dampening unit according to any one of the preceding claims, characterized in that the dampening fountain roller (6) is assigned a metering roller (7) in contact.
7. The dampening unit according to Claim 1 and 2, characterized in that the first rider roller (9) is coupled to a rotary drive and/or an axially oscillating drive.
8. The dampening unit according to Claim 1, 2 and 7, characterized in that the first rider roller (9) has even or uneven circumferential speeds to the dampening form roller (5).
9. The dampening unit according to Claim 1 and 2, characterized in that the first transfer roller (10) is coupled to a rotary drive and/or an axially oscillating drive.
10. The dampening unit according to Claim 1, 2 and 9, characterized in that the first transfer roller (10) has equal or unequal circumferential speeds to the dampening fountain roller (6).
11. The dampening unit according to Claim 1 and 3, characterized in that the second rider roller (13) is coupled to a rotary drive and/or an axially oscillating drive.
12. The dampening unit according to Claim 1, 3 and 11, characterized in that the second rider roller (13) has equal or unequal circumferential speeds to the dampening form roller (5).
13. The dampening unit according to Claim 1 and 3, characterized in that the second transfer roller (14) is coupled to a rotary drive and/or an axially oscillating drive.
14. The dampening unit according to Claim 1, 3 and 13, characterized in that the second transfer roller (14) has equal or unequal circumferential speeds to the dampening fountain roller (6).
15. The dampening unit according to Claim 1 and 6, characterized in that the relative position of the axle of the metering roller (7) to the axle of the dampening fountain roller (6) can be adjusted from an axially parallel position into an obliquely adjustable position and back.
16. The dampening unit according to Claim 1 and 6, characterized in that the axial position of the metering roller (7) is arranged obliquely to the axle of the dampening fountain roller (6).

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