EP1036657B1 - Damping unit for a printing press - Google Patents

Abstract

The damping unit (4) consists of two rubber or plastic coated (6,7) rollers forming a clear gap between them. The first roller (6) is swivel mounted on the second roller by means of a pivot axle (14) running through a center axis (M) of the first roller and parallel with a tangential line running through the gap. The second roller rests against a third roller (8) to form a gap between them. The first roller has an energy accumulator (29) in the form of a spring. The first roller is rotarily mounted on a support (11) connected by a swivel bearing (13) to the printer's (1) frame (12).

Description

The invention relates to a dampening system for a printing press.

DE 37 22 519 A1 describes a dampening system which has a first roller and a includes second roller and in which the two rollers together a slip gap form. The fact that an axis of rotation around which the first roller connects to the second roller is pivotally mounted, lies on a line which passes through a central axis of the first Roller and substantially parallel to one running through the slip gap Tangential line runs, is only in the latter publication graphic shown.

In CH 509 159 a dampening system is also described, in which an intermediate roller in a lever is mounted so that the intermediate roller to and from this transfer and Rubbing roller is on and off. The transfer and friction roller lies on an applicator roller which drives an ink-accepting friction roller via the circumferential friction, the one has copper outer surface.

Another dampening unit is described in EP 0 893 251 A2, the one Dip roller, a slip roller and an intermediate roller comprises. The slip roller turns itself with a surface speed that is different from a Surface speed of the intermediate roller is. As a result, one of those Slip roller together with the nip formed nip a so-called Slip gap. The rollers mentioned only carry dampening solutions and none Printing ink-water emulsion.

In US 4,949,637 still another dampening system is described, which several Contains rollers, each made of rubber and at surface speed of a plate cylinder rotates. Guide all rollers of this dampening system both dampening solution and printing ink during printing. This dampening system is thus a so-called direct film or emulsion film dampening system.

In the brochure "Printing without Isopropanol (IPA)", published by Heidelberger Druckmaschinen AG published series of brochures "GTO 52-Tips" is another Direct film dampening system mentioned, for its operation and maintenance in the prospectus are given.

Further state of the art is also in US 5,540,145, EP 0 462 490 A1 DE 36 37 460 A1 and DE 43 12 523 C2.

The invention has for its object to provide a further dampening system.

The task is performed by a dampening system with the features of claim 1 solved.

The dampening system according to the invention for a printing press consists of a first and a second roller, which together form a slip gap, and wherein an axis of rotation about which the first roller contacts the second roller is pivotally mounted, lies on a line which passes through a central axis of the first Roller and substantially parallel to one running through the slip gap Tangential line runs. In the dampening system according to the invention, the first roller is on Lift mechanism in the form of a spring for storing the first roller around the axis of rotation assigned to the second roller pivoting force.

The use of such an elastic holding the first roller on the second roller Energy store, which with a slight stop movement of the first roller from the second roller acts resilient, is with regard to the exact dosage of an ink fountain solution emulsion extremely beneficial.

The advantage of the dampening system according to the invention is that one in the slip gap shear force occurring does not force the first roller from or to the second roller second roller can cause excessive torque. As a result, they remain Roller pressure in the slip gap and the dampening solution film conveyed by it or preferably ink-fountain solution emulsion film constant.

In addition, the dampening system according to the invention is very good as an emulsion film dampening system for the processing of an alcohol-free dampening solution, which in turn is ecological is advantageous. When shearing an ink fountain solution emulsion in one Experience has shown that emulsion film dampening has a greater shear force than that of the Shear of a color-free dampening solution film in a so-called alcohol dampening system. The high shear forces caused those known from the prior art Emulsion dampening systems constructive and functional restrictions. In contrast there are no such restrictions in the dampening system according to the invention available.

Further constructively and functionally advantageous developments of the invention Dampening units are mentioned in the subclaims and result from the following description of exemplary embodiments and the associated Drawing.

Figur 1

ein Feuchtwerk mit einer ersten und einer zweiten Walze und mit einem Walzenträger, in welchem die zweite Walze drehbar gelagert ist,

Figur 2

die Anordnung einer Drehachse des Walzenträgers,

Figur 3

die Anordnung der Drehachse innerhalb eines keilförmigen Toleranzbereiches,

Figur 4

eine Variante zur Anordnung eines die erste Walze rotativ antreibenden Motors des Feuchtwerkes.

In this shows

Figure 1

a dampening unit with a first and a second roller and with a roller carrier in which the second roller is rotatably mounted,

Figure 2

the arrangement of an axis of rotation of the roller carrier,

Figure 3

the arrangement of the axis of rotation within a wedge-shaped tolerance range,

Figure 4

a variant for the arrangement of a motor of the dampening unit which rotates the first roller.

A printing machine 1 is shown in detail in FIG. The detail shows a printing form cylinder 2, an inking unit 3 and a dampening unit 4 of the printing machine 1, which works with an alcohol-free dampening solution and is designed as a so-called direct film or emulsion dampening unit , which are not shown and together with the printing form cylinder 2 form an offset printing unit. The dampening unit 4 consists of a first roller 6 arranged in a trough-shaped fountain solution container 5 as an immersion roller, a second roller 7 lying on the first roller 6 as a transfer roller in rolling contact, and a third roller lying on the second roller 7 as an axially oscillating friction roller in rolling contact Roller 8, one on the third roller 8 and the printing form cylinder 2 as an application roller in roller contact, and a fourth roller 9, which acts as a metering roller exclusively on the first roller 6 in roller contact. Each of the shortest transport path of the dampening solution from the dampening solution tank 5 for the printing form cylinder 2 forming rollers 6 to 9 and also the fifth roller 10 is provided on the circumference with a color-friendly coating B ₆ to B ₁₀ and leads to an ink-fountain solution emulsion on its peripheral surface coated in this way. The coatings B ₇ , B ₉ and B _{10 of} the rollers 7, 9 and 10 are soft rubber coatings and the coatings B ₆ and B _{8 of} the rollers 6 and 8 are hard rubber or plastic coatings and consist, for. B. made of hard nylon (Rilsan).

The rollers 6 and 10 are rotatably mounted in a common first carrier 11, which around a arranged on a frame 12 first pivot bearing 13 with a Axis of rotation 14 is pivotable. The first carrier 11 consists of two bearing plates, between which bales of rollers 6 and 10 are arranged. By means of a on the first carrier 11 arranged adjusting device 15 is the pressure between the rollers 6 and 10 adjustable by turning a setting thread 16, for. B. a screw that Adjustment device 14 an axle 17 of the fifth roller 10 depending on the direction of rotation Adjustment thread 16 to the first roller 6 and is adjustable away from this.

Around a second one arranged on the frame 12 and coaxial with the third roller 8 A second bracket 20 is pivotally mounted in which the fourth Roller 9 is rotatably mounted. An actuator 21 engages on the second carrier 20 optional turning on and off of the fourth roller 9 to and from the printing form cylinder 2. The actuator 21 is a pneumatic and double acting - d. H. by Pressurized fluid supply both retractable and extendable - working cylinder; which on Frame 12 and its piston rod on the second carrier 20 is articulated.

An electric motor 22 used as a main motor of the printing press 1 rotates the printing form cylinder 2 and the rollers 8 and 9 with a circumferential surface speed v _{8 that is} essentially the same as each other. For this purpose, the motor 22 is connected to the printing form cylinder 2 and the third roller 8 by means of schematically illustrated gear transmissions 23 and 24. The fourth roller 9 is rotated by the third roller 8 with the friction thereof.

An electrical second motor 25 used as a separate motor of the dampening unit 4 - compare FIGS. 4 and 6 - rotates the rollers 6 and 10 at the same peripheral speed v ₆ , which is lower than the peripheral speed v ₈ . As can be seen from FIGS. 4 to 6, the second motor 25 is connected in terms of drive to the first roller 6 via an exclusively torque-transmitting clutch 18 and the fifth roller 10 is rotated by the first roller 6 via friction.

In FIG. 1 it is symbolically shown by rotation arrows accordingly selected that a circumferential surface speed v _{7 of} the second roller 7 is smaller than the circumferential surface speed v ₈ , but larger than the circumferential surface speed v ₆

A preloaded energy or force store 29 in the form of a spring 29 which can be subjected to pressure and is helically wound acts on the first carrier 11, so that the latter is pivoted counter-clockwise with respect to FIG. 1 about the axis of rotation 14. As a result, the energy accumulator 29 holds the first roller 6 in elastic contact with the second roller 7. The energy accumulator 29, which acts as a pushing force against the first roller 6 and the second roller 7, acts in a roller gap (nip) against the first roller 6. N _6.7 compliant. The width of the press strip within the nip N _6.7 between the rollers 6 and 7 is determined by a normal force F _{N, 6.7} applied by the energy accumulator 29 - see FIG. 2. In other words, the energy accumulator 29 presses the first roller 6 against the second roller 7. The wetted peripheral surface of the second roller 7 forms a stop for the first roller 6. Other stops for determining the position of the roller 6 are not necessary.

Due to the difference between the peripheral surface speeds v ₆ and v _{7, the} roller gap N _6.7 is a so-called slip gap due to the difference between the peripheral surface speeds v ₇ and v ₈ and a roller gap N _7.8 between the rollers 7 and 8.

In the press or roller nips N _6.7 and N _7.8 with slip, the liquid transported through the roller nips N _6.7 and N _7.8 is subject to more than one splitting, such as the ink-fountain solution emulsion even in a slip-free nip, but also in shear.

FIG. 2 shows that a force action line k _6.7 corresponds to the normal force F _{N, 6.7 to} a center point of the rolls 6 and 7 and a force _{action line} k _{7.8 to} the normal force F _{N7.8 corresponds to} a center point of the rolls 7 and 8 There is a liquid shear force F _{S, 6.7} along a common tangential line t _{6.7 of} the rolls 6 and 7 determined by the roll gap N _6.7 and a liquid flow along a common tangential line t _7.8 Shear force F _{S, 7.8} effective.

The arrangement of the axis of rotation 14 of the first carrier 11 on a line L running through a central axis M of the first roller 6 and parallel to the tangential line t _6.7 and perpendicular to the force action line k _6.7 or center point of the rollers 6 and 7 ensures that the shear force F _{S, 6, 7 can} not exert any torque on the first carrier 11 which impairs the placement of the first roller 6 against the second roller 7, ie no torque pushing the first roller 6 towards the second roller 7 or pushing it away from the second roller 7 , With any changes in the size of the shear force F _{S, 6.7} , z. B. caused by changes in one of the circumferential surface speeds v ₆ or v _{7 of} the rollers 6 and 7, the normal force F _{N, 6.7} resulting from the pretensioning of the energy accumulator 29 and thus the pressure set between the rollers 6 and 7 remain constant.

In many applications it will be sufficient if the axis of rotation 14 is within a wedge-shaped tolerance range 30 surrounding the line L is arranged. As shown in FIG. 3, the position of tolerance limits 31 and 32 on both sides becomes of the tolerance range 30 of an angle α between the line L and the respective Tolerance limit 31 or 32 defined. The angle α is less than or equal to 15 °.

In the short tangential distance y shown, it is possible to extend the tolerance range 30 by displacing each of the tolerance limits 31 and 32 outward along the force action line k _6.7 by a normal distance x from the line L and the central axis M. It follows from this that the point of intersection of each of the tolerance limits 31 and 32 with the force line of action k _{6.7 is} offset by the normal distance x relative to the line L. The normal distance x is smaller or the same size as the product of a bearing diameter d - z. B. the diameter of a journal 33 - the first pivot bearing 13 and the coefficient of static friction of the first pivot bearing 13, which characterizes the friction between the journal 33 and a bearing bore.

In applications where there is, e.g. B. due to lack of space, not is possible to position the axis of rotation 14 exactly on the line L, should the axis of rotation 14 on that side of the line L and within that half of the tolerance range 30 can be arranged, which is in the direction of the second roller 7 in relation to FIG. 3 this is the left half of the between the line L and the tolerance limit 32 Tolerance range 30.

This results in a self-regulating pressing of the first roller 6 against the second roller 7. An increase in the shear force F _{S, 6, 7} causes the first roller 6 from the second roller 7 - due to the ink / fountain solution emulsion in the roller gap N _{6, 7} without loss of contact - slightly swiveling torque, which automatically. the normal force F _{N, 6.7} exerted by the first roller 6 on the second roller 7 is reduced. The size of the shear force F _{S, 6.7} in turn depends on the normal force F _{N, 6.7} , so that the shear force F _{S, 6.7 is} reduced as a result of the reduction in the normal force F _{N, 6.7} . The dampening unit 4 reacts in the opposite manner when the shear force F _{S, 6.7 is} reduced.

FIG. 4 shows a possible variant for introducing a driving force F _A that generates the speed difference in the nip N _6.7 . In this variant, it is ensured that the driving force F _A does not transmit a torque which pivots the first roller 6 about the axis of rotation 14 and thereby adversely affects the constancy of the pressure in the roller gap N _{6, 7} to the first carrier 11.

According to the variant, this is ensured by the fact that the motor 25 attached to the frame 12 transmits its torque to the first roller 6 via the clutch 18 without restoring forces. The clutch 18 connects a shaft 36 rotated by the motor 25, for example a motor shaft of the motor 25, to a pin-shaped roller axis 37 of the first roller 6 which is coaxial to the shaft 36. The clutch 18 is designed as a sleeve clutch and consists of two permanently connected clutch halves , namely a gear 26 which is seated in a rotationally fixed manner on the shaft 36 and a gear 27 which is seated in a rotationally fixed manner on the roller axis 37. The gears 26 and 27 are enclosed by a flexible sleeve 28 which has two toothings on the inside, in which the gears 26 and 27 engage.
Instead of the coupling 18 shown, a flexible shaft, a double cardan joint, a curved tooth coupling, a parallel crank coupling or another compensating coupling to compensate for inclination and / or misalignment deviations for driving connection of the motor 25 to the first roller 6 can also be used.

A central axis M of the first roller 6 is predetermined by the roller axis 37, around which axis the first roller 6 rotates.

Instead of the motor 25, a brake can also be arranged to brake the rotation of the roller 6 and to generate the slip in the nips N _6.7 and N _7.8 . The brake would have to be arranged stationary on the frame 12.

LIST OF REFERENCE NUMBERS

1

press

2

Plate cylinder

3

inking

4

dampening

5

Dampening solution container

6

first roller (dipping roller)

7

second roller (transfer roller)

8th

third roller (friction roller)

9

fourth roller (applicator roller)

10

fifth roller (metering roller)

11

first carrier

12

frame

13

first swivel bearing

14

axis of rotation

15

adjustment

16

adjustment threads

17

journal

18

clutch

19

second swivel bearing

20

second carrier

21

actuator

22

Motor (main motor)

23

gear transmission

24

gear transmission

25

Motor (separate motor)

26

gear

27

gear

28

shell

29

power storage

30

tolerance

31

tolerance limit

32

tolerance limit

33

pivot

36

wave

37

roll axis

B ₆

coating

B ₇

coating

B ₈

coating

B ₉

coating

B ₁₀

coating

d

Bearing diameter

F _A

driving force

F _{N, 6.7}

normal force

F _{N, 7.8}

normal force

F _{S, 6.7}

shear

F _{S, 7.8}

shear

k _A

Line of action

k _6.7

Line of action

k _7.8

Line of action

L

line

M

central axis

N _6.7

Roller gap (slip gap)

N _7.8

Roller gap (slip gap)

t _6.7

tangent

t _7.8

tangent

v ₆

Circumferential surface velocity

v ₇

Circumferential surface velocity

v ₈

Circumferential surface velocity

x

normal distance

y

tangential distance

α

angle

Claims (12)

1. The moistening unit (4) for a printing machine (1) consisting of a first roller (6) and a second roller (7) together forming a slip gap (N_6,7), whereby a pivot axis (14) about which the first roller (6) is pivotably supported against the second roller (7) is located on a line (L) which extends through a center axis (M) of the first roller (6) and substantially parallel to a tangential line (t_6,7) extending through the slip gap (N_6,7) and wherein the first roller (6) is assigned a force storing means (29) in the form of a spring for storing a positioning force that pivots the first roller (6) against the second roller (7) about the pivot axis (14).
2. The moistening unit of claim 1,
   characterized in that the second roller (7) is in contact with a third roller (6) and together form a roller gap (N_7,8) .
3. The moistening unit of claim 2,
   characterized in that the roller gap (N_7,8) is a slip gap.
4. The moistening unit of one of claims 1 to 3,
   characterized in that the first roller (6) and the second roller (7) each have a coating (B₆, B₇) with an affinity for ink on their circumference.
5. The moistening unit of claim 4,
   characterized in that the coatings (B₆, B₇) consists of rubber or a plastic.
6. The moistening unit of one of claims 1 to 5,
   characterized in that the first roller (6) is rotatably supported on a carrier (11) for pivoting the first roller (6) about the pivot axis (14), and the carrier (11) is connected to a frame (12) of the printing press (1) via a pivot bearing (13) that determines the pivot axis (14). ,
7. The moistening unit of claim 6,
   characterized in that a motor (25) for rotationally driving the first roller is disposed on the frame (12) and is connected for driving to the first roller (6) via a coupling (18).
8. The moistening unit of one of claims 1 to 7,
   characterized in that the first roller (6) is an immersion roller.
9. The moistening unit of one of claims 2 to 8,
   characterized in that the third roller (8) is a traversing friction roller.
10. The moistening unit of one of claims 2 to 9,
    characterized in that the third roller (8) rests on a fourth roller (9).
11. The moistening unit of claim 10,
    characterized in that the fourth roller (9) is an applicator roller that rests on a form cylinder (2).
12. A printing press (1) having a moistening unit (4) embodied according to one of claims 1 to 11.

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