EP0667237A1 - Automated printing plate changing device - Google Patents

Abstract

A printing plate to be fed to the plate cylinder is conveyed between driven transport rollers and counter pressure rollers. The driven transport rollers (15) and the corresp. counter pressure rollers (13) are movably located in the axis direction of the plate cylinder (1). The transport rollers together with the counter pressure rollers, with the printing plate (11) located on the plate cylinder, are effective in the middle of the format length of the printing plate. The transport rollers and the counter pressure rollers have a curved contour. The axes of the counter pressure rollers are adjustable in respect of the orientation to the drive shaft. The transport rollers are arranged on a common drive shaft which incorporates a drive.

Description

The invention relates to a device for automatically changing printing plates of a printing press, in particular sheet-fed offset printing press, according to the preamble of claim 1.

In conventional sheetfed offset printing machines, a lot of time-consuming manual operations have to be carried out to change a printing plate of the plate cylinder. For example, a used printing plate must be removed from the plate cylinder by loosening the clamping and tensioning of the print start and print end clamping rails, and a new printing plate must first be inserted into the printing start clamping rail in the reverse order of the work processes and then clamped and tensioned at the end of the print. In order to shorten the time for retrofitting a sheetfed offset printing machine, a number of semi or fully automatic printing plate changing systems have been developed.

From DE 4 215 969 A1, a semi-automatic printing plate changing system is known, in which an insertion rail which can be adjusted to the plate cylinder is provided, by means of which the printing start edge of a new printing plate is inserted into the corresponding clamping rail of the plate cylinder. For this purpose, the vertically movable protection in front of the printing unit cylinders has a gap at its upper end from which a pressure plate to be removed can be removed by an operator and via which - after the insertion rail has been inserted - a new pressure plate to be supplied is inserted into the start of the tensioning rail by the operator . The device is clamped and tensioned on the plate cylinder by means of corresponding remote-controlled actuating means.

From EP 0 431 575 A2 and DE 4 130 359 A1 magazines for the automatic printing plate change are known, in which linearly movable suction cups are provided for feeding a new printing plate to the plate cylinder. In order to ensure a supply of the new printing plates in accordance with the register, EP 0 431 575 A2 provides register pins which can be countersunk in the magazine and to which the new printing plate to be fed is aligned.

A disadvantage of these known printing plate magazines is the relatively complex and therefore also to be regarded as prone to failure. In order for a new printing plate to be fed to the plate cylinder in register with these plate changing systems, it is therefore necessary that the printing plate be carefully and therefore time-consumingly aligned when it is inserted into the magazine. A further disadvantage is that these magazines block the space between the printing units in the position of the printing plate change and therefore expensive additional protection must be provided so that an operator is not injured by the corresponding switch-on and switch-off movements.

From DE 3 940 796 C2, a printing plate magazine suspended in front of the printing unit is known, which has a storage chamber for the old as well as for the new printing plate to be fed. This magazine is curved in its lower part facing the plate cylinder and furthermore, in the lower part of this magazine, driven transport rollers, counter pressure rollers and pivotable ejection fingers are provided for removing a used printing plate. The described devices for changing or feeding the printing plates are all located in the lower area of the magazine and therefore in the vicinity of the plate cylinder. It is therefore not possible to hang this magazine movably on the printing unit via a vertical guide. Rather, it is provided to pivot the magazine from an operating position to a service position by means of parallel rockers. During this pivoting movement, the magazine also executes a movement into the space between the printing units, which in turn requires additional safety means to protect an operator. In this magazine too, the new printing plate to be fed in must be precisely pre-positioned, since otherwise a correct supply to the plate cylinder cannot be guaranteed. This device also provides a so-called position detector for the printing plate to check the register-correct system.

The object of the present invention is therefore to develop a device according to the preamble of claim 1 in a structurally simple manner in such a way that a register-correct supply of the printing plate to the plate cylinder is always guaranteed.

This object is achieved by the characterizing features of claim 1. Further developments of the invention result from the subclaims.

Due to the axial mobility of the transport rollers, the printing plate is not automatically aligned in the magazine with respect to the side register of the plate cylinder.

According to a development of the invention, it is provided that the transport rollers are mounted in such a way that they act on the printing plate in approximately half the format length when the new printing plate is inserted into the tensioning rail assigned to the start of printing.

It is also provided that the conveying direction of the transport rollers is oriented at an angle with respect to the direction of insertion of the detection area of the pressure start tensioning rail.

This measure ensures that even a printing plate which is not set exactly in the magazine with respect to the circumferential register of the plate cylinder can be inserted exactly into the latter due to a deflection which differs across the format width.

The device according to the invention can be arranged in a very compact and space-saving manner above a protection which is known per se and can be moved vertically in front of the printing unit cylinder and can effect the feeding of a new printing plate via a guide device which is likewise known and can be adjusted to the plate cylinder. The transport rollers according to the invention can then either be arranged in an integrated manner in the upper part of a protection or can be designed as a removable or pivotable attachment.

Furthermore, an embodiment of the invention is explained with reference to the drawing.

• Fig. 1 und 2 prinzipiell einen Schnitt durch die an einem vertikal vor dem Druckwerkszylinder verfahrbaren Schutz angebrachte Vorrichtung,
• Fig. 3 und 4 die Anordnung der Transportrollen oberhalb des Schutzes im Detail,
• Fig. 5 und 6 die Ausbildung der Aufhängung der Transportrollen,
• Fig. 7 und 8 das Prinzip des selbsttätigen Ausrichtens durch die erfindungsgemäße Ausbildung der Transportrollen, und
• Fig. 9 eine Detaildarstellung einer der den Transportrollen zugeordneten Gegendruckrolle.

It shows:

• 1 and 2 in principle a section through the device attached to a vertically movable in front of the printing unit protection device,
• 3 and 4, the arrangement of the transport rollers above the protection in detail,
• 5 and 6, the formation of the suspension of the transport rollers,
• 7 and 8 the principle of automatic alignment by the inventive design of the transport rollers, and
• 9 shows a detailed illustration of one of the counterpressure rollers assigned to the transport rollers.

1 and 2 show a part of a printing unit of a sheet-fed offset printing press with a plate cylinder 1, which carries a front tensioning rail 3 assigned to the start of printing DA in an axially parallel pit 2. The front tensioning rail 3 has, in a manner known per se, a format-wide gap as a detection area 4 for the edge of a printing plate 11 to be newly fed which is assigned to the start of printing DA. The remotely controllable actuating means (not shown here) can open the detection area 4 and also close it after clamping to insert a new pressure plate 11. A blanket cylinder 5 is shown below the plate cylinder 1.

A vertically movable guard 6 is attached in front of the printing unit cylinders 1 and 5 shown in FIGS. 1 and 2. For this purpose, the protection 6 is suspended on both sides via vertical guides (not shown here), each attached to a side frame wall.

Within the guard 6 facing the plate cylinder 1 axially spaced from each other two stops 7 are arranged, on which a new pressure plate 11 to be fed, pushed through a gap at the top of the guard 6, is placed with its front edge. This gap at the top of the protection 6 is formed by two guide plates 8 and 9. So that a used pressure plate 12 can be conveyed out at the top of the guard 6, a further guide plate 10 is provided that forms a second gap with the guide plate 9. The gaps formed by the guide plates 8, 9, 10 for the new and also the old printing plate 11, 12 have a length at the top of the protection 6 which is greater than the maximum format width of the printing plates to be processed.

Above the protection 6 and above the guide plates 8, 9, 10, a pair of axially spaced counter pressure rollers 13, 14 is attached (FIG. 6). Optionally adjustable to the pair of counter pressure rollers 13 and 14, a pair of driven transport rollers 15 is pivotally suspended. The pair of transport rollers 15 can thus be placed either on the pair of counter pressure rollers 14 or on the pair of counter pressure rollers 13, as shown in FIGS. 1-4. The drive of the transport rollers 15 is such that the transport rollers 15 rotate counterclockwise.

1, a pressure plate 11 to be newly supplied is placed through the gap between the pairs of counter-pressure rollers 13 and the transport rollers 15 and through the gap formed by the guide plates 8 and 9 into the protection 6 on the stops 7. In a manner known per se, a used printing plate was removed after loosening a holding device (not shown here) corresponding to the printing end by turning the plate cylinder 1 backwards (contrary to the normal direction of rotation shown here) through the gap of the guide plates 9 and 10 from the top of the guard 6 promoted. The plate cylinder 1 is rotated back until it assumes the position shown in FIG. 1, which also serves to insert a new printing plate. The transport rollers 15 are then brought up against the counter-pressure rollers 14 and the pressure plate 12 is pulled out of the opened detection area 4 of the tensioning rail 3 by the rotation of the transport rollers 15.

So that the edge (not shown here) when the pressure plate 12 is being conveyed away can get into the gap between the guide plates 9 and 10 and thus into the detection area of the transport rollers 15 with the counter-pressure rollers 14, the guide plate 9 is as shown in FIGS. 1 and 2 in the protection 6 pulled down. At the end of the guide plate 9, flexible guide tongues 16 are also spaced apart, on which the leading edge of the pressure plate 12 can slide. An inlet protection 17 located in front of the inking unit rollers shown also assumes a guiding function.

As indicated in FIGS. 1 and 2, an insertion rail 18 which can be pivoted about an axis (not shown) is arranged in front of the plate cylinder 1 and is in the basic position in FIG. 1. This insertion rail 18 has 7 recesses in the area of the stops, so that the pivotable end of the insertion rail 18 is not hindered by the stops 7 and can reach under the front edge of the pressure plate 11.

By pivoting the insertion rail 18 against the plate cylinder 1 (FIG. 2), the pressure plate 11 is thus removed with its front edge from the stops 7 and the insertion rail 18 forms with the outer contour of the plate cylinder 1 at the start of the print DA a funnel-shaped area for inserting the front edge of the pressure plate 11 in the open detection area 4 of the tensioning rail 3.

As shown in FIG. 2, the pressure plate 11 is bent in its lower region towards the plate cylinder 1 by the pivoting of the insertion rail 18 after the transport rollers 15 have been placed against the counter pressure rollers 13. The flexible guide tongues 16 also yield. Now the transport rollers 15 are actuated again, so that the front edge of the pressure plate 11 is inserted into the opened tensioning rail 3 (the detection area 4), whereupon the pressure plate is clamped. The insertion rail 18 is pivoted back into its basic position (FIG. 1) and the clamped pressure plate 11 is drawn up by rotating the plate cylinder 1 (direction of arrow) around its outer circumference, whereupon the clamping and tensioning of the printing end of the pressure plate 11 takes place by means not shown here.

So that the trailing end of the printing plate is not damaged by parts within the protection 6 when the printing plate 11 is pulled onto the plate cylinder 1, strip-shaped brushes 19 are arranged axially spaced apart from one another on the inside of the protection.

3 to 6, the attachment of the counter-pressure rollers 13, 14 and the transport rollers 15 pivotally driven between them is shown above the protection 6. As can be seen in FIGS. 5 and 6, the pair of transport rollers 15 is mounted on a common drive shaft 21 which has a drive 28 at one end. The drive shaft 21 is supported at both ends via bearings on the pivotable end of a pivot lever 24. Spherical roller bearings are preferably used here, so that bending of the drive shaft 21 is also possible. The two pivot levers 24 are in turn attached to the ends of a common pivot shaft 23 and connected to it in a rotationally fixed manner.

In Fig. 5 it is shown that the common pivot shaft 23 is suspended in each case on a frame part 22 attached above the protection 6 via bearings. 6, the frame parts 22 have a U-shaped shape in plan view and each consist of two opposite walls in which the counter-rollers 13, 14 are mounted and a support arm connecting the two walls. The pivotable through the pivot axis 23 via the pivot lever 24 drive shaft 21 is passed through an opening 25 in the support arm of the frame part 22, so that the transport rollers 15 on the counter-pressure rollers 13, 14 mounted in the walls of the frame part 22 are selectively adjustable. According to FIGS. 3 and 4, the transport roller 15 can therefore be turned on the counter-pressure rollers 13 by pivoting the pivot shaft 23 either against the counter-pressure rollers 14 for conveying out a used pressure plate 12 or for feeding a new pressure plate 11. It is further provided that the transport rollers 15 can also be pivoted into a central position, not shown, in which they therefore do not rest against the counter-pressure rollers 13 or against the counter-pressure rollers 14.

The mounting of the pivot shaft 23 within the two frame parts 22 is designed such that not only a smooth pivoting movement but also, as indicated by the arrow in FIGS. 5 and 6, axial mobility of the pivot shaft 23 with respect to the frame parts 22 is possible. For this purpose, the pivot shaft 23 is preferably mounted in the support arm of the frame part 22 via a needle bearing, which is seated in a spherical roller bearing.

So that the swivel shaft 23 and also the transport rollers 15 located on the drive shaft 21 always assume a centered starting position, springs 26 are arranged at both ends of the swivel shaft 23 between the bearing lever 24 and the frame part 22. Due to the described suspension of the pivot shaft 23, the transport rollers 15 and their common drive shaft 21 are thus floating in the axial direction. The drive 28 of the drive shaft 21 also carries out the corresponding axial movements.

For pivoting the pivot axis 23, a pivot drive 27 is attached to the side of the protection 6 opposite the drive 28, which is coupled in this way to the pivot shaft 23, so that the axial movement is possible speed of the unit shown pivot shaft 23, pivot lever 22 and drive shaft 21 is not hindered. The swivel drive 27 can advantageously be a rotary vane motor that can be operated with compressed air or pneumatic cylinders arranged in pairs. The drive 28 is advantageously designed as an electric motor. The drive 28 can also act via a freewheel on the drive shaft 21, so that a used pressure plate 12 can be pulled out of the guard 6 when the transport rollers 15 are in contact with the counter-pressure rollers 14 (FIGS. 1 and 3). Not shown are holding means for the used printing plate 12, so that it also remains in the protection 6 (FIG. 1) when the transport rollers 15 are parked by the counter pressure rollers 13.

As shown in FIGS. 3, 4 and 6, the counter-pressure rollers 13 and 14 assigned to the pair of transport rollers 15 are likewise mounted in the frame part 22 via an axis 20 in each case. The counter-pressure rollers 13 (see FIG. 4) that serve to feed a new pressure plate 11 are, as shown in FIG. 9, also movably mounted in the axial direction on an axis 20 attached in the frame part 22. Here, too, a bearing is used (needle bearing), which not only enables easy rotation, but also axial mobility of the counter-pressure roller 13, which is essentially designed as a bushing, with respect to the axis 20. According to FIG. 9, each counter-pressure roller 13 is centered via two springs 31 which are supported at the other end in the frame part 22. In Fig. 9 it can also be seen that the counter-pressure rollers 13 have a barrel-shaped profile. The transport rollers 15 also have such a spherical outer contour, and the counter-pressure rollers 14 can also be shaped in this way.

It is preferably provided that the axis 20 in the frame part 22 can be adjusted with regard to its orientation to the drive shaft 21. This can be achieved in that the axle 20 is inserted at one or both ends with a corresponding fit via eccentric bushings in the wall of the frame part 22 (not shown in FIG. 9). Through a skewed orientation of the counter pressure rollers 13 with respect to the transport rollers 15, an advantageous spreading effect of the pressure plate 11 during conveying can be achieved.

According to FIG. 7, it is preferably provided that the axial distance between the transport rollers 15 on the drive shaft 21 is the same as the distance between the punched-outs which are provided on the front edge of the pressure plate 11 and which are provided with register pins 29 arranged on the plate cylinder 1 (in the detection area of the tensioning rail 3). work together. The driving force of a new pressure plate 11 to be fed is thus introduced in the circumferential direction just above the punched-out portions 30.

According to the invention it is further provided that on the one hand the transport rollers 15 introduce the driving force approximately half the format length of the printing plate 11 and further that the printing plate 11 experiences a conveying direction F through the transport rollers 15, which is at an angle W to the insertion direction E of the plate leading edge extends into the open detection area 4 of the tensioning rail 4. The angle W is therefore formed by the conveying direction F and the orientation of the detection area 4, which is exaggerated in FIG. 8. In conjunction with the axial mobility of the transport rollers 15 with the corresponding counter-pressure rollers 13 provided in accordance with the invention, this results in an automatic correction and thus a registration-correct application of a new printing plate 11 when it is applied with the punched-out portions 30 to the register pins 29. This is shown in principle in FIGS. 7 and 8.

In Fig. 7, a slightly rotated with respect to the registered position oriented printing plate 11 is shown in dashed lines. If this pressure plate 11 (dashed line) with its punched-out 30 is conveyed to the register pins 29 of the plate cylinder 1, the punched-out 30 shown on the left in FIG. 7 first reaches the register pin 29. A possible lateral offset of the pressure plate 11 (dashed line) is indicated by the axial mobility of the transport rollers 15 and the corresponding counter-pressure rollers 13 compensated. Since the pressure plate runs curved between the transport rollers 15 and the counter pressure rollers 13 and the register pins 29, as shown in FIG. 8, the pressure plate is bent somewhat more strongly in the region of the edge a (FIG. 7) when the punched-out portions 30 are pressed against the two register pins 29 than in the area of the edge b. This different deflection is possible because the pressure plate 11 is not bent on a curved conveying surface but freely between the transport rollers 15 and the detection area. The new pressure plate 11 to be fed is thus moved exactly into the register of the plate cylinder 1 (tensioning rail 3) if it was only roughly aligned in the guard 6 (on the stops 7) by side stops (not shown).

Reference list

• 1 plate cylinder
• 2 pit
• 3 tensioning rails
• 4 detection area
• 5 blanket cylinders
• 6 protection
• 7 stop
• 8 guide plate
• 9 guide plate
• 10 guide plate
• 11 pressure plate (new, feed)
• 12 pressure plate (used)
• 13 counter pressure roller
• 14 counter pressure roller
• 15 transport roller
• 16 guide tongues
• 17 Inlet protection
• 18 insertion rail
• 19 brushes
• 20 axis
• 21 drive shaft
• 22 frame part
• 23 swivel shaft
• 24 swivel levers
• 25 breakthrough
• 26 spring
• 27 quarter turn actuator
• 28 drive
• 29 register pins
• 30 die cut
• 31 spring
• DA start of printing
• F conveying direction
• E direction of insertion
• W angle

Claims (10)

1. Device for automatically changing printing plates of a printing press, in particular sheet-fed offset printing press, in which a printing plate to be fed to the plate cylinder is conveyed between driven transport rollers and counter-pressure rollers,
characterized,
that the driven transport rollers (15) and the corresponding counter-pressure rollers (13) are movably mounted in the axial direction of the plate cylinder (1). 2. Device according to claim 1,
characterized,
that the transport rollers (15) and the counter pressure rollers (13) act on the plate cylinder (1) against the printing plate (11) approximately in the middle of the format length of the printing plate (11). 3. Device according to claim 2,
characterized,
that the conveying direction (F) checked by the transport and counter pressure rollers (15, 13) of the pressure plate (11) at an angle (W) to the direction of insertion (E) of the front edge of the pressure plate (11) into the detection area (4) of the tensioning rail ( 3) of the plate cylinder (1) moved into a predetermined angular position. 4. Apparatus according to claim 1, 2 or 3,
characterized,
that the transport rollers (15) and the counter pressure rollers (13) have a spherical contour. 5. Device according to one of the preceding
Expectations,
characterized,
that the axes (20) of the counter-pressure rollers (13) are adjustable with regard to their orientation to the drive shaft (21). 6. Device according to one of the preceding
Expectations,
characterized,
that the transport rollers (15) are arranged on a common drive shaft (21) which has a drive (28), and
that the drive shaft (21) are connected at both ends via swivel levers (24) to an axially movably mounted swivel shaft (23). 7. Device according to one of the preceding
Expectations,
characterized,
that the axially movable transport rollers (15) and the counter pressure rollers (13) are centered by springs (26, 31) in an initial position. 8. Device according to one of the preceding
Expectations,
characterized,
that the transport rollers (15) and the counter-pressure rollers (13, 14) are arranged on the top of a vertically movable protection (6) in front of the printing unit cylinders (1, 5). 9. The device according to claim 8,
characterized,
that the transport rollers (15) and the counter pressure rollers (13, 14) on the top of the protection (6) are arranged as a removable unit. 10. Device according to one of the preceding
Expectations,
characterized,
that the transport rollers (15) and the corresponding counter-pressure rollers (13) have the same axial spacing as on the front edge of the pressure plate to be fed (11) cutouts (30) which cooperate with register pins (29) located on the plate cylinder (1).

Images