DE8915693U1 - Device for automatically changing a printing plate - Google Patents

Description

G 89 15 693.5 Aus,ßtajischsieit£ _# ·· _{§ t} « 1991-01-31

Description

Device for automatically changing a printing plate

The invention relates to a device for automatically changing a printing plate on a plate cylinder of a rotary printing machine.

EP-A-02 68 857 discloses a semi-automatic device with which it is possible to attach a printing plate to the plate cylinder of a rotary printing press.

The disadvantage of the device according to EP Note 02 68 857 is that the printing plate must be inserted into the clamping device by hand; in addition, the commands for placing the printing plate, clamping it and tightening it must be entered manually on a control panel.

The invention is based on the object of creating a device for changing a printing plate on a plate cylinder.

The object is achieved according to the invention by the features of the characterizing part of claim 1.

The advantage of the device according to the invention lies in the fact that for fastening the printing plates on the plate cylinder

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Auxiliary personnel can be deployed. Personnel cannot come into contact with the rotating parts of the machine, i.e. safety is increased. Machine downtimes for changing the printing plates are reduced.

The register-relevant position of the plate on the plate cylinder becomes more precise. Waste caused by time-consuming register correction is reduced.

An embodiment of the invention is shown in the drawings and is described below. They show

Fig. 1 is a side view of the printing plate changing device according to the invention in section,

Fig. 2 an enlarged section of the representation of the side view of the transport area of the printing plate changing device,

Fig. 3 an enlarged side view of the clamping device for a printing plate end, "Printing plate clamping position",

Fig. 4 an enlarged side view of the clamping device for a printing plate start, "printing plate feed position",

Fig. 5 Control device and control computer, Fig. 6 a flow chart.

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A rotary printing press has several printing units 1 (e.g. 4), each of which contains, among other things, a plate cylinder 3, a blanket cylinder 4 and an impression cylinder ft. These are mounted in the usual way in side positions of the rotary printing press.

Since the various printing units 1 are almost identical to one another, the invention is only described using one printing unit 1.

A printing plate changing device 9 is provided on an access side 8 to the cylinders 3, 4, 6 of the printing unit 1. The printing plate changing device 9 is attached to a cover plate 11, which serves as a coupling. This is arranged together with the printing plate changing device 9 so that it can be pivoted vertically into two end positions by means of two rockers 17; 18, which are attached to the side frames of the printing towers 1. The pivoting joints are shown by dashed lines. For this purpose, an upper and lower joint 14; 16 is provided on a front and rear side of the cover plate 11, in which a first end of the rocker 17; 18 is pivotably mounted. A second end of the rocker 17, 18 is pivotably mounted on the side frames. The cover plate 11 as a coupling, the rockers 17, 18 and the frame of the printing unit 1 as a web thus form a four-bar linkage.

At a lower end on both sides of the cover plate 11, a double-acting working cylinder 19 is pivotally mounted. A piston rod 21 of the working cylinder 19 is connected in an articulated manner to a lever 22. The lever 22 carries a rotatable

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mounted a continuous pressure roller 26 arranged parallel to the axis of the plate cylinder 3 with a drive 23. The pressure roller 26 can also be offset. The pressure roller 26 has a surface (e.g. rubber; plastic) that is soft in relation to a pressure plate 27. The lever 22 is pivotally mounted about an axis 30 of a drive roller 28 that is rotatably mounted in side supports (not shown) of the cover plate 11. The drive roller 28 is offset and has a drive (e.g. gear drive/electric motor, pneumatic motor, etc.).

In the exemplary embodiment, this is schematically represented by a sprocket 31 with a drive chain 32.

However, the drive roller 28 and the pressure roller 26 can also be connected to one another in a drive connection, e.g. by a chain drive, whereby they should preferably have the same circumferential speeds.

The drive roller 28 is in driving contact with another drive roller 29 (e.g. gear drive) in such a way that the drive rollers 28, 29 rotate in opposite directions, i.e. in a roller gap formed by the drive rollers 28, 29 they have a common transport direction. All transport rollers have a soft, elastic surface (e.g. rubber) which is at least softer than the pressure plates 27, 60 used? so that they cannot damage them.

A pressure roller 33 is arranged to be brought into contact with the driven drive roller 29. For this purpose, the

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Pressure roller 33 is rotatably mounted in a first end of a two-armed lever 34.

The lever 34 is pivotally mounted almost centrally in the side supports of the cover plate 11 and has a bearing point 36 at the second end into which one end of a piston rod 37 engages in an articulated manner. The piston rod 37 is part of a working cylinder 40 which is articulatedly attached to the cover plate 11.

The printing plate changing device 9 consists of a housing approximately the width of the printing plate with two storage chambers 73, 74. When viewed in section, the housing has a slight curvature such that an upper part of the housing is aligned almost vertically and a lower part of the housing is aligned tangentially towards a lower part of the plate cylinder 3.

The housing is constructed in two parts and has a hinge 42 above the cover plate 11, by means of which an upper part of the housing can be folded down, whereby an upper part of the printing tower 1, in which an inking unit (not shown) of the printing machine is usually provided, is accessible to an operator.

A front wall 43 of the housing extends to just before the pressure roller 26 and has openings 44 in the area of the drive roller 28 through which surface areas of the offset drive roller 28 protrude from below into the storage chamber 73. A rear wall 46 of the housing extends to just before the

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Pressure roller 33.

A wall 78 separates the storage chambers 73, 74 from each other and extends until just before the drive roller 29, where it ends in two guide plates 79, 81, which

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Printing plate 27, 60 enters the correct roller gap.

Behind the pressure roller 33, parallel to a wedge-shaped guide plate 76, several ejection fingers 45 are provided, which are fixedly arranged on an ejection finger shaft 47 pivotably mounted in the side supports of the cover plate 11. At a distance from the pivotable mounting of the ejection finger shaft 47, a piston rod 48 articulates on a lever 50 of the ejection finger shaft 47 to actuate them. The piston rod 48 is part of a working cylinder 49, which is articulated to the cover plate 11. The ejection fingers 45 can be pivoted by means of the piston rod 48 in such a way that their tips 68 dip into the periphery 62 of the plate cylinder or lift off the periphery 62.

The plate cylinder 3 has a plate clamping and tensioning device 53, 54 in a pit ¹ ^?. The plate clamping device is known, for example, from DE-PS 36 26. This is characterized in particular by a favorably arranged pivot pole of the clamping flap 55; 56. This has the effect that a printing plate end 57 is not hindered by the clamping flap 55 when it is inserted into or removed from the plate clamping device.

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The clamping device is known, for example, from DE-OS 36 04 071.

When the plate cylinder 3 is rotated from a printing plate release position A in a clockwise direction (backwards) and pressure is applied to the working cylinder 49, the tips 68 of the gripper fingers 45 pass through corresponding openings 64 in the clamping flap 55 into recesses 65 in the plate clamping and tensioning device 54 under the printing plate end 57 and thus support a lifting of the printing plate end 57 from a clamping support

The actuating means provided for the plate clamping and tensioning device 53, 54 are supplied with working medium via a rotary inlet on the plate cylinder journal. It is of course also possible to provide devices that supply the plate cylinder with working medium via its front side or outer surface when it is at a standstill in a plate cylinder position A; B; C. The actuating means can be designed as hydraulic, pneumatic, mechanical or even electrical units.

During printing operation, the printing plate storage 9 is in a position as shown in Fig. 1 and Fig. 2. In this position, access to the cylinders 3, 4, 6 is closed by the cover plate 11; however, the pressure roller 26 and the gripper fingers 45 are pivoted away from the plate cylinder 3.

In a printing plate release or feed position A, B, the pressure roller 26 is positioned against the plate cylinder 3.

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After completion of the current print job, the plate cylinder 3 moves into the predetermined angular position A (printing plate release position) (Fig. 2). The clamping cap 55 is opened. One printing plate end 57 springs outwards due to its own elastic tension until it strikes the guide plate 76 or is lifted off the clamping support 63 by the ejection fingers 45 by further rotating the center cylinder 3 into the printing plate clamping position C.

A clockwise rotation of the plate cylinder 3 (backwards) now causes the printing plate 27 to be pushed out into the storage chamber 74, whereby the pressure roller 26 is driven anti-clockwise with a preselectable torque. The torque must not exceed the friction between the plate 27; 60 and the roller surface 26.

The printing plate end 57 enters a gap between the drive roller 28 and the stopped pressure roller 33. The printing plate 27 is transported through the gap between the transport rollers 29, 33 into the storage chamber 74 until the plate cylinder 3 reaches the printing plate feed position B and the clamping flap 55 opens to hold the printing plate beginning 58. Almost simultaneously, the pressure roller 33 is positioned against the drive roller 29 by means of the working cylinder unit Y1, 40. Activating the drive 31, 32 now causes the printing plate 27 to be pulled out of the contact area, ie the lower part of the printing plate changing device 9, and fed into the storage chamber 74.

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At the same time, the drive rollers 28, 29 transport a printing plate 60 previously introduced (stored) into the storage chamber 73 into the application area until the printing plate start 58 of the new printing plate 60 hits a stop 51 of the plate clamping and tensioning device 53. A position detector 59 for monitoring the position of the printing plate 27; 60 on the stop 51 sends a "good" signal to a control computer 66, whereupon the clamping flap 56 is closed. The printing plate 58 is clamped in place. The plate cylinder 3 is now rotated counterclockwise (forwards) while the pressure roller 26 presses the printing plate 60 against the plate cylinder 3. However, if the position detector 59 signals a poor contact of the printing plate 60 with the stop 51 of the plate clamping device 54, a corresponding fault signal is generated.

When a plate cylinder position (printing plate clamping position) C (Fig. 3) is reached, in which the printing plate end 57 is pressed by the pressure roller 26 onto the clamping surface 63, the clamping flap 55 closes and clamps the printing plate end 57. Subsequent activation of the clamping elements clamps the printing plate 60 onto the plate cylinder 3.

Position C is, in degrees of angle, only slightly (e.g. 5° - 10°) behind the printing plate release position A, i.e. the plate cylinder 3 only has to be turned a little bit anti-clockwise from the printing plate release position A until it reaches position C (Fig. 3).

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In position C, the pressure roller 26 has slightly folded the printing plate end 57 around an edge 61 of the plate cylinder pit 52, so that the printing plate end 57 comes to rest within the periphery 62 of the plate cylinder 3 on the clamping support 63 of the clamping device 54 before it is held by the clamping flap 55.

The pressure roller 26 is then pivoted back into the printing press operating position by the double-acting working cylinder 19, which is pressurized with pressure medium, retracting the piston rod 21 and pivoting the pressure roller 26 away from the plate cylinder 3 about the axis 30 of the drive roller 29. The printing plate change is completed.

The control computer 66 is connected to a number of solenoid valves 67 which, when a printing plate change command is given, switch in the correct order depending on the positions of the plate cylinder 3 and in conjunction with suitable software and supply the actuating cylinders with working medium from a pressure source (Fig. 4).

The positions A, B, C of the plate cylinder 3 are determined by means of a rotary angle sensor 71 and fed to the control computer 66 (Fig. 4).

All electrical drives (e.g. plate cylinder drive M; drive of the transport roller 33) are also controlled by the control computer 66. The software of the control computer works according to a flow chart (Fig. 6), so that all steps 101 - 137

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are carried out automatically one after the other.

After actuating a start trigger 101 (Fig. 6), safety conditions of the rotary printing machine are checked in a first step 102 (e.g. is the cover plate 11 closed?). If all safety conditions are not met, a fault signal 103 is generated. If the safety conditions are met, a start-up warning signal is generated in a subsequent step 104.

After repeated actuation of the start trigger 10 1 (by hand or triggered by the control computer 66), the plate cylinder 3 rotates into the plate cylinder position A in step 106. Once the plate cylinder position A is reached, the pressure roller 26 is placed against the plate cylinder 3 in a step 107, then the plate tension is switched off in step 108, the clamping flap 55 is opened in step 109, the ejection fingers 45 are pivoted into the periphery 62 of the plate cylinder 3 in step 111 and the transport roller 33 is pivoted away from the drive roller 29 in step 112.

In a subsequent step 113, the drive 23 is activated and the plate cylinder 3 is moved backwards into the plate cylinder position B. After a circumferential path (approx. 50 mm) has been covered, the ejection fingers 45 are swung out of the periphery in a step 114. The plate cylinder 3 continues to rotate without interruption until it reaches the plate cylinder position B (step 116). Once the plate cylinder position B is reached, the drive 23 is switched off in a step 117. In step 118, the pressure roller 33 is connected to the drive roller

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29 employed.

In step 119, the clamping flap 56 is opened. In the following step 121, the pressure roller 26 is moved slightly away from the plate cylinder 3 and serves only as a guide for the old and new printing plates 27, 60. After that, the drives 31, 32 are activated in step 122 and the plate tension is turned off (step 123). The old printing plate 27 is now transported out of the clamping device 54 by means of the transport rollers 29; at the same time, the new printing plate 60 is transported from the storage chamber 73 to the clamping device 54.

In a step 124, a position detection of the new printing plate 60 is queried. If the plate position is not correct, the printing plate 60 continues to be fed by means of the transport rollers 28, 29. If the printing plate 60 is still not correctly positioned after repeated queries by the position detector 59, a fault signal 126 is generated. However, if the positioning of the printing plate 60 on the stop 51 is correct, the drive 31, 32 is switched off in step 127.

In steps 128 _to 129, the clamping flap 56 is closed and the pressure roller 26 is placed against the plate cylinder 3 under slight pressure.

In the following step 131, the plate cylinder 3 is moved forward into the plate cylinder position A; at the same time, the drives 23, 31, 32 are activated. When the plate cylinder position A is reached, the drives 31, 32 are switched off in step 132.

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In step 133, the plate cylinder position C is approached and then in step 134 the clamping flap 55 is closed, in step 135 the plate tension is turned on and in step 136 the pressure roller 26 is switched off and off. The printing plate change is finished; an end signal 137 is generated.

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Parts list

1 printing unit

3 plate cylinders

4 blanket cylinders

6 impression cylinders

8 Access page

9 Printing plate changing device

11 Cover plate

14 Joint (upper)

16 Joint (lower)

17 Swingarm

18 Swingarm

19 working cylinders

21 Piston rod

22 levers

23 Drive

26 Pressure roller

27 Printing plate

28 Drive roller

29 Drive roller

30 Axis

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31 Sprocket

32 Drive chain

33 Pressure roller

34 levers

36 Storage location

37 Piston rod

40 working cylinders

42 Hinge

43 Front wall (9)

44 breakthroughs

45 ejection finger

46 Rear wall (9)

47 Ejection finger shaft

48 Piston rod

49 working cylinders

50 levers

51 stop

52 Pit (3)

53 Plate clamping and tensioning device

54 Plate clamping and tensioning device

55 Clamping flap

56 Clamping flap

57 Printing plate end

58 Printing plate start

59 Position detectors

$0 Printing plate (new)

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61 Edge (52)

62 Peripherals (3)

63 clamp support (54)

64 breakthroughs

65 Recess (54)

66 tax calculator

6 Solenoid valve

68 Peak (45)

71 rotary encoder

72 Pressure source

73 Storage chamber

74 Storage chamber

76 Guide plate

78 Wall

79 Guide plate

81 Guide plate

) . ) Follow-up steps of the flow chart

A Printing plate release position B Printing plate feed position C Printing plate clamping position M Plate cylinder drive

Claims (12)

G 89 15 693.5 Exchange page 1991-01-31 • - '\ '· &igr;* : : : *: pi.764de Claims 1. Device for automatically changing a printing plate (27) on a plate cylinder (3) of a rotary printing machine, which has, among other things, means (53. 54) for clamping and tensioning the printing plate (27), characterized in that the Pressure plate, axis 1 device (9) has at least two storage chambers (73, ;4), that the pressure plate changing device (9) has a number of iansport rollers (28, 29, 33). 2. Device according to claim 1, characterized in that at least one transport roller (28; 29) has a drive (31, 32). 3. Device according to claim 2, characterized in that the pressure roller (33) is arranged so as to be adjustable to the drive roller (23') . 4. Device according to claims 2 and 3, characterized in that computer-controlled actuating means (37, 40, 67) are provided for generating an adjusting movement of the pressure roller (33). 5. Device according to claims 3 and 6, characterized in that a pivotably mounted pressure roller (26) is provided, that the pressure roller (26) has a drive (23). 6. Device according to claim 5, characterized in that adjusting means (19, 21, 67) are provided for generating a pivoting movement of the pressure roller (26). G 89 15 693.5 Exchange page 1991-01-31 ! &Iacgr; . i :" ." . *..! *: pi .764de &iacgr;# · I 1 * 7. Device according to claim 2, characterized in that ejection catches (4.5) are provided. 8. Device according to claims 2 and 7, characterized in that the ejection fingers (45) are fastened to a pivotably mounted ejection finger shaft (47). 9. Device according to claims 2, 7 and 8, characterized in that the ejection fingers (45) have tips (68) that the tips (68) are arranged to be pivotable into the periphery (62) of the plate cylinder (3). 10. Device according to claims 2, 7 to 9, characterized in that openings (64) are provided in the clamping flap (55) of the plate clamping and tensioning device (54) and recesses (65) are provided in the plate clamping and tensioning device (54). 11. Device according to claims 2, 7 to 10, characterized in that adjusting means (48, 49, 67) are provided for generating a pivoting movement of the ejection fingers (45). 12. Device according to claim 2, characterized in that the pressure plate storage (9) is made in two parts and has a joint (42) connecting the two parts.