EP1036657A2 - Damping unit for a printing press - Google Patents

Abstract

A dampening unit (4) for a printing press (1) consists of a first roller (6) and a second roller (7), which together form a slip gap (N _{6, 7} ).

The dampening unit (4) is characterized in that an axis of rotation (14), about which the first roller (6) is pivotally mounted on the second roller (7), lies on a line (L) which is defined by a central axis (M ) of the first roller (6) and essentially parallel to a tangential line (t _6.7 ) running through the slip gap (N _6.7 ).

Description

The invention relates to a dampening system for a printing press, consisting of a first Roller and a second roller, which together form a slip gap, after the Preamble of claim 1.

EP 0 893 251 A2 describes such a dampening unit, which has an immersion roller Includes slip roller and an intermediate roller. The slip roller turns with one Surface speed, which is different from a surface speed the intermediate roller is. As a result, one of the slip rollers along with the The nip formed between the nip is a so-called slip nip. The above Rollers only contain dampening solution and no ink / dampening solution emulsion.

In US 4,949,637 another dampening system is described, which several Contains rollers, each of which is 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.

Printing without Isopropanol (IPA)", der von der Fa. Heidelberger Druckmaschinen AG herausgegebenen Prospektreihe GTO 52-Tips" ist ein weiteres Direktfilmfeuchtwerk erwähnt, zu dessen Bedienung und Pflege in dem Prospekt Hinweise gegeben werden.In the prospectus

Printing without Isopropanol (IPA) ", the brochure series published by Heidelberger Druckmaschinen AG GTO 52-Tips "mentions another direct film dampening system, the operation and maintenance of which are given in the brochure.

Further state of the art is also in US 5,540,145, EP 0 462 490 A1 DE 36 37 460 A1, DE 37 22 519 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 is characterized by it from that an axis of rotation about which the first roller is pivotable to the second roller is stored, lies on a line which through a central axis of the first roller and in Essentially parallel to a tangential line running through the slip gap runs.

One of the advantages of the dampening system according to the invention is that an in Slip nip shear force no the first roller from the second roller can cause pushing or pushing to the second roller torque. As a result, the roller pressure remains in the slip gap and that which is conveyed by it Fountain solution film 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.

For example, in the dampening system according to the invention, it is possible without problems, the first Roll an energy accumulator, e.g. B. a spring for storing the first roller around the Assign axis of rotation to the second roller pivoting positioning force. The use of a such an energy accumulator holding the first roller elastically on the second roller a slight stop movement of the first roller from the second roller acts, is with regard to the exact dosage of an ink fountain solution emulsion extremely beneficial.

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.

1 shows a printing machine 1 in a detail. The section shows a printing form cylinder 2, an inking unit 3 and one with an alcohol-free dampening solution working and trained as a so-called direct film or emulsion dampening Dampening unit 4 of the printing press 1. The latter is used as a rotary printing press Printing of printed material sheets formed and further includes one Blanket cylinder and an impression cylinder, which are not shown and form an offset printing unit together with the printing form cylinder 2.

The dampening unit 4 consists of a first roller 6 arranged in a trough-shaped dampening 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 to form the printing form cylinder 2 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 first carrier 11 arranged adjusting device 15 is the pressure between the rollers 6 and 10 adjustable by turning a setting thread 16, z. 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 support 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 which 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- rotatively drives 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 with it.

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 engages the first carrier 11, so that the latter is pivoted counterclockwise 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 moistened 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.

The roller gap N _6.7 is a so-called slip gap due to the difference between the peripheral surface speeds v ₆ and v ₇ and a roller gap N _7.8 between the rollers 7 and 8 is a so-called slip gap due to the difference between the peripheral surface speeds v ₇ and v 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 also in a slip-free nip, but also in shear

FIG. 2 shows that a force line of action k _6.7 corresponds to the normal force F _{N, 6.7 to} a center point of the rollers 6 and 7 and a force line of action k _{7.8 to} the normal force F _7.8 corresponds to a center point of the rolls 7 and 8 . Along a common tangential line t _6,7 rollers 6 and 7 determined by the nip N _6,7 is a liquid shear force F _{S, 6,7} and along a common tangential line t _{7,8 of} the rollers 7 and 8 is a liquid 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 the 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 on 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 resulting from the bias of the energy accumulator 29 normal force F _{N, 6.7} and thus the set pressure between the rollers 6 and 7 remains 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 one Tolerance limit 31 or 32 defined. The angle α is less than or equal to 15 °.

With 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 be arranged, which is in the direction of the second roller 7. Referring to Figure 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 pressure of the first roller 6 against the second roller 17. An increase in the shear force F _{S, 6, 7} causes the first roller 6 from the second roller 7- due to the printing ink / fountain solution emulsion in the roller gap N _{6, 7} without loss of contact - torque which swings slightly, by means of which the normal force F _{N, 6.7} exerted by the first roller 6 on the second roller 7 is automatically 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 in 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, e.g. B. a motor shaft of the motor 25, with a coaxial to the shaft 36 pin-shaped roller axis 37 of the first roller 6. The clutch 18 is designed as a sleeve clutch and consists of two permanently connected coupling halves, namely a gear 26 and a non-rotatably seated on the shaft 36 Gear 27 seated in a rotationally fixed manner on the roller axis 37. The gear wheels 26 and 27 are enclosed by a flexible sleeve 28 which has two toothings on the inside into which the gear wheels 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.

Reference list

1

Printing press

2nd

Printing form cylinder

3rd

Inking unit

4th

Dampening system

5

Fountain solution container

6

first roller (dipping roller)

7

second roller (transfer roller)

8th

third roller (distribution roller)

9

fourth roller (applicator roller)

10th

fifth roller (metering roller)

11

first carrier

12th

frame

13

first swivel bearing

14

Axis of rotation

15

Adjustment device

16

Adjustment thread

17th

Axle journal

18th

clutch

19th

second swivel bearing

20th

second carrier

21

Actuator

22

Motor (main motor)

23

Gear transmission

24th

Gear transmission

25th

Motor (separate motor)

26

gear

27

gear

28

Sleeve

29

Lift mechanism

30th

Tolerance range

31

Tolerance limit

32

Tolerance limit

33

Bearing journal

34

./.

35

./.

36

wave

37

Roller 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 force

F _{S, 7.8}

Shear force

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

Tangential line

t _7.8

Tangential line

v ₆

Peripheral surface speed

v ₇

Peripheral surface speed

v ₈

Peripheral surface speed

x

Normal distance

y

Tangential distance

α

angle

Claims (14)

Dampening unit (4) for a printing press (1), consisting of a first roller (6) and a second roller (7), which together form a slip gap (N _6.7 ),
characterized by
that an axis of rotation (14) about which the first roller (6) is pivotally mounted on the second roller (7) passes through a central axis (M) of the first roller (6) and essentially parallel to one through the slip gap (N _{6 , 7} ) extending tangent line (t _6.7 ). Dampening unit according to claim 1,
characterized by
that the second roller (7) rests against a third roller (8) and forms a roller gap (N _7,8 ) with it. Moisture detector according to claim 2,
characterized by
that the roll gap (N _7.8 ) is a slip gap. Moisture detector according to one of claims 1 to 3,
characterized by
that the first roller (6) and the second roller (7) each have a color-friendly coating (B ₆ and B ₇ ) on the circumference. Dampening unit according to claim 4,
characterized by
that the coatings (B ₆ and B ₇ ) consist of rubber or a plastic. Dampening unit according to one of claims 1 to 5,
characterized by
that the first roller (6) is assigned a force accumulator (29) for storing an adjusting force which pivots the first roller (6) about the axis of rotation (14) against the second roller (7). Dampening unit according to claim 6,
characterized by
that the energy accumulator (29) is a spring. Dampening unit according to one of claims 1 to 7,
characterized by
that the first roller (6) is rotatably mounted on a carrier (11) for pivoting the first roller (6) about the axis of rotation (14) and the carrier (11) via a pivot bearing (13) determining the axis of rotation (14) Frame (12) of the printing press (1) is connected. Dampening unit according to claim 8,
characterized by
that a motor (25) for rotatingly driving the first roller is arranged on the frame (12) and is drivingly connected to the first roller (6) via a clutch (18). Dampening unit according to one of claims 1 to 9,
characterized by
that the first roller (6) is an immersion roller. Dampening unit according to one of claims 2 to 10,
characterized by
that the third roller (8) is an oscillating friction roller. Dampening unit according to one of claims 2 to 11,
characterized by
that the third roller (8) abuts a fourth roller (9). Dampening unit according to claim 12,
characterized by
that the fourth roller (9) is an application roller which bears against a printing form cylinder (2). Printing machine (1) with one designed according to one of claims 1 to 13 Dampening system (4).

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