EP0662046A1

EP0662046A1 - Process and device for adjusting the contact pressure of a synthetic-blanket roller in rotary printing presses

Info

Publication number: EP0662046A1
Application number: EP93920656A
Authority: EP
Inventors: Georg Schneider; Ewald RÖTHLEIN
Original assignee: Koenig and Bauer Albert AG; Koenig and Bauer AG
Current assignee: Koenig and Bauer AG
Priority date: 1992-09-25
Filing date: 1993-09-23
Publication date: 1995-07-12
Anticipated expiration: 2013-09-23
Also published as: US5485785A; EP0662046B1; WO1994007695A1; DE4232163C3; DE4232163A1; DE59308290D1; JPH08501510A; DE4232163C2

Abstract

A device for maintaining an even roller mark with rubber rollers for rotary printing presses is designed to avoid scumming by keeping constant a roller mark produced between a form cylinder (12) and the rubber lining (29) of an inking roller (26), independent of heat increase in the rubber lining (29) when the press is running. The invention thus provides that the inking roller (26) can be adjusted to the form cylinders (12) by means of levers (1) fixed to the frame which hold the inking roller (26) in roller carriages, where the levers are adjustable against stops (15) fixed to the frame, and elastic elements (14) susceptible of thermal expansion are arranged between the levers (1) and the stops (15).

Description

description

Method and V ^"orrichtung for adjusting the contact pressure of a provided with a plastic sheath roll in a rotary printing machine

The invention relates to a method for maintaining a set contact pressure in the form of a roller strip and a device for carrying out the method according to the preamble of claim 1.

From DE 21 55 496 C2 a generic device for adjusting the pressure of inking rollers against the forme cylinder is known, by means of which a reference ring is moved against cams, so that the inking rollers provided with elastic surfaces against the forme cylinder are adjustable with respect to their axes. For this purpose, the reference ring has an arm that can be adjusted using an adjusting screw.

A disadvantage of the device mentioned is that the adjustment of the contact pressure of the rubber roller after the rotary printing machine has been started up is done at the operator's discretion, both in terms of time and in terms of the size of the actuating amount, so that a temperature-dependent ink supply to the forme cylinder cannot be excluded.

The invention has for its object to provide a method and an apparatus for performing the method for rotary printing presses with short inking units, with which it is possible to keep the width of the so-called roller strip formed by pressing the inking roller against the forme cylinder approximately constant in the event of temperature changes.

According to the invention, this object is achieved by the features of the characteristics of claims 1 and 2.

The following advantages occur in particular when using the invention. A uniformly formed roller strip, regardless of the degree of warming of the rubber blanket, ensures a constant print quality through an even application of ink. The object of the invention is particularly advantageously used in anilox offset short inking units and especially when the forme cylinder and the inking roller have the same diameter. In addition, the susceptibility to toning can be reduced. The invention is not only limited to offset short inking units. The quantity of transfer of the ink from the inking roller to a printing plate, e.g. B. offset printing plate, a forme cylinder over a temperature range between approach temperature and operating temperature and thus the quality of the transfer of the ink from the inking roller to the printing plate can be kept almost constant.

In addition, it is avoided that an excessive contact pressure between the form cylinder and the inking roller and thus a toning occurs. The too strong contact pressure can lead to flexing of the elastic covering of the inking roller and thus to the destruction of the elastic covering.

The invention is intended to several

Exemplary embodiments are explained in more detail. Show in the accompanying drawings

Figure 1 is a schematic side view of a short inking unit of a rotary offset printing machine in anilox design with the device according to the invention.

FIG. 2 shows a detail of a detail "Z" according to FIG. 1 ;

FIG. 3 shows a detail of the detail "Z" according to FIG. 1, but with a second exemplary embodiment;

4 shows the schematic representation of a third exemplary embodiment corresponding to the device according to the invention;

5 shows the schematic representation of a fourth exemplary embodiment corresponding to the device according to the invention;

6 shows a block diagram for the exemplary embodiment according to FIG Fig. 5;

Fig. 7 is a schematic representation of a fifth embodiment according to the device according to the invention;

FIG. 8 shows a detail of a detail y according to FIG. 7;

Fig. 9 is a block diagram of the embodiment of FIG. 4;

10 shows a schematic illustration of a sixth exemplary embodiment corresponding to the device according to the invention;

11 shows a section XI - IX according to FIG. 10.

1 shows a schematic side view of a short inking unit in anilox construction. A one-armed lever 1 is pivotally mounted in the horizontal direction A at its first end 2 in the side frame 3 of a printing press via a bearing 4 on a journal 6 of an anilox-type anilox roller 7 mounted on the frame. An ink supply to the anilox roller 7 is not shown to simplify the facts. A second end 8 of the lever 1 is connected to one end of a piston rod 9 of a double-acting working cylinder 11. The end of the piston rod 9 can Eyelet formed and connected to the second end 8 of the lever 1 via a threaded bolt. The working cylinder 11 is rotatably arranged on the side wall 3 of the machine frame via a threaded bolt 10. The working cylinder 11 has at its two ends nozzle 13 for supplying and discharging the fluid, for. B. hydraulic oil or compressed air, from a corresponding system, not shown. The lever 1 can consist of sheet steel with a thickness of ten to fifteen millimeters. The second end 8 of the lever 1 can be moved according to the arrow A in the direction of a forme cylinder 12 up to a stop designated overall by 15, with the special feature that between the stop 15 and the second end 8 of the lever 1 a member designated overall by 14 is arranged. The element 14 is with the end face of the second end 8 of the lever 1, for. B. connected by screwing and is explained as a detail Z in FIGS. 2 and 3.

The stop 15 consists of a part-fixed bolt 16 on which an eccentric 17 and a one-armed lever 18 are rotatably received with its first end in the axial direction. A second end of the lever 18 is connected to a threaded bolt 21 via a joint 19. The hinge 19 consists of a hinge pin with a threaded bore running at right angles to its longitudinal axis, in which the threaded bolt 21 is mounted. The threaded bolt 21 is guided through a bore of a frame fixed bearing block 22 and with a Provide twist grip. Thus, the stop 15 is roughly adjustable by the eccentric 17 and finely adjustable by the threaded bolt 21 acting on the lever 18.

Between both ends 2; 8 of the lever 1 runs approximately in the middle of the lever 1, a semicircular holder 23 for receiving an axle 24 of an inking roller designated overall by 26, which can be closed by a removable holding part 27 analogous to known roller lock r. A bearing 28 is arranged between the holder 23 or a bearing shell 27 and the journal 24. On the outer surface of the inking roller 26, a known rubber cover 29 or rubber covering or an existing printing blanket made of rubber or a Gummiin is pulled up. The surface of the rubber cover 29 is in permanent connection with the surface of the anilox roller 7, which delivers the printing ink from its wells to the inking roller 2.

The inking roller 26 can be adjusted by means of the working cylinder 11 via the element 14 against the adjustable stop 15. This takes place in the idle state of the machine and has the effect that the forme cylinder 12 presses with a defined compressive force on the rubber cover 29 of the inking roller 26 and produces a roller strip 31 or a flattening with a width b. The forme cylinder 12 is mounted fixed to the frame in addition to the inking roller 26 via trunnions 34 and 36. 2 shows an element 14 corresponding to the detail Z according to FIG. 1. The element 14 is detachably connected to the end face of the lever 1 at its second end 8 by means of screws 35 indicated in the drawing. The element 14 consists of two strip-shaped metal plates 37; 38, e.g. B. made of steel, between which in a "sandwich construction" a thicker, cuboid Tempe ratureinf luß-Kornensensator 39 made of plastic with the thickness d and the same length and width fixed, z. B. is glued. The outside of the metal plate 38 of the element 14 facing the forme cylinder 12 is in the operating state against the eccentric 17 of the stop 15.

All of the above-mentioned components or elements of the device are double in front, but are not shown or shown separately. Such components are e.g. B. lever 1, bearing 4; 28, axle pins 6 and the like. This did not, however, is still valid for the components 41 ois 106 for the printing cylinder 12, the Fa ^'rbauftrag SwaI ze 26 to the rubber cover 29 and the anilox roller 7.

The setup works as follows. Due to the internal friction in the rubber cover 29 of the ink roller 26, heat is generated during the operating state, which results in an expansion of the rubber cover 29 and thus an increase in the outer diameter of the inking roller 26, which normally results in an increase in the width of the roller strip 31 and thus b to widened banding, which in turn leads to poor print quality. In order to compensate for the enlargement of the roller strip 31 set to the width b when the mascnine is at rest, the strip expands

Temper ature influence compensator 39 of the element 14 due to the heat, so that the second end 8 of the lever 1 moves in the direction of the working cylinder 11 and thus the compressive force between the rubber cover 29 of the inking roller 26 and the pressure plates 32; 33 of the form cylinder 12 remains the same.

The width b of the roller strip 31 extending in the axial direction of the inking roller 26 thus remains constant and thus also the quality of the printed image.

The plastic strip 39 of the element 14 can, for. B. made of polyamide PA 12 according to DIN 7728 with a linear expansion coefficient of

150 ^* 10 - f. K - 1, which also corresponds to a linear expansion coefficient of the rubber cover 29. Starting from the representation in FIG. 1, the ratio of the length of the imaginary distances between points F and G and F and H is like one to two. The point F represents the pivot or pivot point of the lever 1, the point G denotes the axis of rotation of the inking roller 26 and the point H denotes the point of contact or line of contact between the element 14 and the eccentric 17 of the stop 15. Given the same expansion coefficients of the rubber cover 29 and the temperature influence compensator 39, it is necessary with an above-mentioned lever ratio of one to two that the temperature influence compensator 39 has to expand by two millimeters so that the Cylinders 12, 26 arranged in one plane are separated by one millimeter, ie the width b of the roller strip 31 decreases. Accordingly, the thickness d of the plastic body 39 of the element 14 in the arrangement of the printing press cylinders shown in FIGS. 1 and 4 corresponds to twice the thickness of the rubber cover 29 of the inking roller 26.

When using a material for a temperature influence compensator 39 with a linear expansion coefficient twice as large as the polyamide PA 12 mentioned and the same thickness d of the material 39 of the rubber cover 29, this also ensures that a roll strip 31 which is always uniformly wide is also ensured. The heat generated during the operating state of the inking roller 26 is passed on via the lever 1 to the elements 14 located on the second ends 8 of the lever 1, as a result of which the thermal expansion of the elements 14 takes place. In fact, however, it is the case that the heating of the rubber cover 29 proceeds continuously during the operating state and thus also the element 14 is heated via the lever 1. This in turn has one uniform expansion of the temperature influence compensator 43 and thus a constant width b of the roll strip 31 result.

3 shows a second exemplary embodiment of an element 41. A metallic support or sleeve 42, e.g. B. made of steel, is releasably connected by means of screws 35 to the end face of the second end 8 of the lever 1 and has a bore in the center in the direction of its thickness e, which is filled by a cylindrical temperature influence compensator 43 made of plastic. The end of the cylindrical temperature influence compensator 43 facing away from the second end 8 of the lever 1 is provided with a metal disk 44, e.g. B. made of steel, z. B. by indicated screws 35. This metal disc 44 is used for the exact fixing of the element 41 against the stop 15 with the eccentric 17. The operation of the element 41 according to FIG. 3 corresponds to that of the element 14 according to FIG. 2.

4 shows a third exemplary embodiment of a device according to the invention. Above the inking roller 26, a known thermal sensor 46 is attached to the lever 1, which measures the temperature on the surface of the rubber cover 29 during operation and sends this to a sensor shown in FIG. 9 shown computer 61 and amplifier 66 reports that a heating source 47, z. B. a heating cartridge in one Actuator 48 operates until the material between the two metal plates 37; 38, in which the heating source 47 is embedded, expands due to heating so that the roller strip 31 remains constant in its width b. The actuator 48 is connected to the end face of the lever 1 by screws 35 analogously to the element 14 according to FIG. 1. Said substance can be made of plastic, e.g. B. polyamide exist. In this embodiment, the temperature measurement on the rubber cover 29 ensures that the actuator 48 is only heated and expanded by the heat source 47 to such an extent that a roller strip 31 of constant width b is always guaranteed.

According to the representation in Fig. 5 shows a fourth exemplary embodiment of a device according to the invention. The lever 1 pivotally arranged on the bolt 16 fixed to the frame with its first end 2 has at its second end 8 a fork guide 49 with which a sliding block 51 is moved. The sliding block 51 can be moved by means of an internal thread on a threaded spindle 52 which is mounted in the bearing blocks 53; 54 is stored. The outside of the Lagerbδcke 53; 54 lying ends of the threaded spindle 52 each accommodate a motor 56 fixed to the frame or are connected to a potentiometer 57 fixed to the frame. Motor 56 and potentiometer 57 are each via cable 58; 59 connected to a symbolically represented computer 61. 5 and 6, the computer 61 a keyboard 62 parameter 63; 64 entered about the coefficient of thermal expansion and the thickness of the rubber cover 29 of the inking roller 26. The thermal sensor 46 feeds the actual value of the temperature of the rubber cover 29 to the computer 61. The position of the sliding block 51 and thus the position of the lever 18 with the eccentric 17 to the second end 8 of the lever 1 is known via the potentiometer 57 '. From the data mentioned, the computer 61 calculates a setpoint value which is fed via an amplifier 66 to the motor 56, which rotates the threaded spindle 52 until the eccentric 17 has moved the lever 1 against its force against the force of the working cylinder 11, so that the desired width b of the roller strip 31 is set. The device for adjusting the eccentric 17 against the end face of the second end 8 of the lever 1 is denoted overall by 67.

According to the illustration in FIG. 7, a fifth exemplary embodiment of a device according to the invention is shown, in which an actuator, designated overall by 68, is connected by means of screws 35 analogously to the actuator 48 in FIG. 4 on the end face of the second end 8 of the lever 1. The actuator 68 is again manufactured in a “sandwich construction” and, according to FIG. 8, has three parallel metal plates 69 arranged at a distance i1 and i2 from one another; 71; 72, between which there are piezoelectric force generators 73; 74 located. Now the force generator 73; 74 via the metal plates 69; 71; 72 is subjected to a DC voltage, the center between the force generators 73; 74 arranged metal plate 71 must always have a different polarity as the two, the force generators 73, 74 from the outside adjacent metal plates 69; 72, the thicknesses or the distances i1 and i2 change either positively or negatively, depending on the above-mentioned polarity.

The actuator 48 shown in FIG. 4 with the heat source 47 located therein can be controlled via the computer 61 as shown in FIG. 9, as described in FIG. 6, with the special feature that an inductive displacement sensor 76 is arranged , which measures the extent d, see FIG. 2 with element 14, and sends this actual value to the computer 61.

Likewise, the actuator 68 shown in FIG. 8 according to FIG. 9 can be controlled via the computer 61. For this purpose, the heating source 47 is actuated by the actuator 68 with the connections 77; 78 replaced.

A further exemplary embodiment is shown as shown in FIG. 10. A forme cylinder 12 with pressure plates 32, 33 is mounted via its journal 34 in a bearing 36 in the side frame 1 of the machine. A holder 79 is likewise mounted on the bearing journal 34 of the forme cylinder 12 and receives an eccentric bushing 81 for an axle journal 24 of an inking roller 26 with a rubber cover 29. The axis of rotation of the journal 24 of the inking roller 26 is designated 82 and the axis of rotation of the eccentric bush 81 is designated 83. A bearing shell 27 surrounds the eccentric bush 81 and is connected to the holder 79. The pins 24, 34 of the inking roller 26 and the forme cylinder 12 are arranged by the holder 79 at such a distance from one another that their surfaces touch each other and give a roller strip 31 with a width b. In order to be able to vary the width b of the roller strip 31 automatically as a function of the heating of the rubber cover 29, a stop designated 84 is provided in the form of a nose and a lever 86 fastened to the eccentric bushing 81, between which an element 87 is arranged. The element 87 is shown enlarged in FIG. 11 and consists of a sleeve 88, which at its first end 89 is connected in an articulated manner to the stop 84 of the holder 79 via a pin 91. The stop 84 has a not shown groove for receiving the first end 89 of the sleeve 88. In the sleeve 88 there is a temperature influence compensator 92, for. B. of polyamide, with the same coefficient of thermal expansion as that of the rubber cover 29 of the inking roller 26. In the sleeve 88 is after the temperature influence compensator 92 in the direction of the second At the end 93 of the sleeve 88 there is a sliding element 96 which is provided with a threaded bore 94 and is movable in the axial direction of the sleeve 88.

The sliding member 96 has at its end the temperature influence compensator 92 facing in the radial direction, the sliding element 96 penetrating pin 97, which is guided with its respective end in an axial direction of the sleeve 88 slot 98, 99 and is thus secured against rotation . A set screw 101 is rotatably arranged in the threaded bore 94 of the sliding element 96 and passes through a bearing 102 with a threaded bore. The bearing 102 is attached to the lever 86 connected to the eccentric bushing 81. At the end of the screw 101 is an actuator 103, for. B. square, provided for turning the screw 101 and thus for presetting the roller strip 31.

A plate spring assembly 104 is provided between the actuating element 103 and the bearing 102. Between the upper end of the lever 86 and the upper end of the stop 84, a working cylinder 11 is mounted parallel to the element 87 as a spring. When expanding the plastic temperature influence compensator 92 in element 87 analogous to element 41 in FIG. 3, the plastic body 92 expands as a result of the heat effect and moves the sliding element 96 in the axial direction of the adjusting screw 101, so that the eccentric bushing 81 over the Lever 86 is rotated counter-clockwise and the axis of rotation 82 of the journal 24 of the inking roller 26 moves away from an axis of rotation 106 of the forme cylinder 12 so that the width of the roller strip 31 remains constant despite thermal expansion. The journal 6 of the anilox roller 7 is fixed to the frame and centrally via a bearing 4. The contact pressure or the distance between the journal 6 of the anilox roller 7 and the journal 24 of the inking roller 26 can be carried out by means of an adjusting device 107 which is fixed to the frame, ie by turning an adjusting element analogous to that with the designation 103, the one about the axis of rotation 106 of the plate cylinder 12 pivotable holder 79 can be adjusted against the anilox roller 7.

It is also possible to use a distance measuring device 46, e.g. B. a laser measuring device or an infrared range finder. This distance measuring device, as shown in FIGS. 4 and 5, can be fastened on the lever 1 and measures the distance from the surface of the inking roller 26 provided with the rubber cover 29 at intervals. In the computer 61 according to FIGS. 6 and 9, deviating from the input The following parameters were entered as parameters for parameters 63, 64. Diameter of the inking roller 26 and the forme cylinder 12, length of the lever 1 from the pivot point F to the stop 15, length of the lever 1 from the pivot point F to the axis of rotation G of the inking roller 26. As a result of a program stored in the computer 61, due to the change in the distance between the surface of the inking roller 26 and the distance measuring device, the drives symbolically shown in FIGS. 6 and 9 for changing the distance of the inking roller 26 to the forme cylinder 12 are started,

Roller strips / flattening pressure plate pressure plate bearing pin screw

Calculator keyboard (61) Parameter thermal expansion coefficient (29) Parameter thickness (29) - amplifier actuator actuator metal plate - metal plate metal plate piezoelectric force generator piezoelectric force generator - displacement transducer, inductive connection (68) connection (68) holder - eccentric bushing rotation axis (24) rotation axis (81) Stop (79) - lever (81) element sleeve end, first (88) - 91 cones (87)

92 temperature influence compensator (87) 93 end, second (88)

94 threaded hole (96)

95 -

96 sliding element

97 pen (96)

98 slot (88)

99 slot (88)

100 -

101 set screw

102 bearings

103 actuator

104 spring washer package

105 -

106 rotation axis (12)

107 adjusting device 108

109

110 -

A Direction of movement b Width

Z detail d thickness (39) e length (43)

F pivot point (1)

G axis of rotation (26)

H contact line (14) i1 thickness (68) i2 thickness (68)

Claims

1. A method for maintaining a set pressure in the form of a roller strip with a plastic jacket, for. B. rubber, provided metal roller to a forme cylinder of a rotary printing press having a short inking unit with changing roller temperature, characterized in that the inking roller (26) by means of a fluid-loaded working cylinder (.11) indirectly or directly against a frame-fixed stop defining the roller width (b) ( 15, 84) is pressed, that after the change in heating of the patch application roller (26) or parts thereof, an automatic direct or indirect movement of the ink application roller (26) in the radial direction towards the forme cylinder (12) towards or away from the forme cylinder (12), is produced.

2. Device for performing the method according to claim 1, characterized in that means (9, 10, 11, 1, 14, 15; 9, 10, 11, 1, 41, 15; 8b, 11, 84, 87; 9 , 10, 11, 1, 48, 15; 46, 61, 56; 9, 10, 11, 1, 68, 15, 46, 61, 56; 9, 10, 11, 1, 67, 15, 46, 61 , 56) for generating a self-daily movement of the

Ink application roller (26) in the radial direction towards the forme cylinder (12) to or from the forme cylinder (12) depending on a change in heating of parts or the entire ink application roller (26), based on a temperature at the time of presetting the roller strip (31) in a desired width (b) are provided.

3. Device according to claim 2, characterized in that the means for generating an automatic movement of the inking roller (26) from a against the force of a fluid-loaded working cylinder (11) movable temperature influence compensator (39, 43, 92) or an actuator ( 48, 68, 67), which are arranged between the bearing (28) of the inking roller (26) and a stop (15, 84) fixed to the frame.

4. Device according to claims 2 and 3, characterized in that the temperature influence compensator (39, 43, 92) consists of a heat-sensitive, length-extensible plastic.

5. Device according to claims 2 and 3, characterized in that the actuator (48) consists of a plastic heat source (47).

6. Device according to claims 2 and 3, characterized in that the actuator (68) consists of metal plates (69, 71, 72) arranged piezoelectric forces (73, 74).

7. Device according to claims 2 and 3, characterized in that the actuator (67) consists of a threaded spindle (52) driven by a motor (56).

8. Device according to claims 2, 3 and 5 to 1, characterized in that the actuator (48, 68, 67) via a computer (61) with a temperature we t on the surface of the

Ink application roller (26) measuring thermo sensor (46) is connected that the thermo sensor (46) transmits an actual value to the computer (61), that the computer (61) determines a target value and sends this to the actuator (48, 68, 67) forwards.