EP0826500B1 - Adjusting device for printing plates - Google Patents

Abstract

An device for adjusting the tension applied on a printing plate on a plate cylinder of a sheet fed offset printing machine is provided. The device includes a clamping bar comprising at least one clamping bar section and having a clamping gap which receives an end of the printing plate. Moreover, the clamping bar is arranged so that it can move approximately in the circumferential direction of the plate cylinder. The device further includes a spring element which acts on the clamping bar so as to apply a tensile force on the printing plate. The device also includes an adjusting element pivotally supported on the cylinder such that it can be pivoted counter to the force of a spring from a disengaged position into engagement with the clamping bar in order to selectively reduce the tensile forces exerted on the printing plate by the spring element.

Description

The invention relates to an adjusting device for printing plates according to the preamble of Claim 1.

In sheetfed offset presses, they are fed onto the plate cylinders of the printing units fastening printing plates with their start of printing edge on a corresponding one Fastening device clamped on the plate cylinder and then around the outer circumference of the plate cylinder. Then the printing end edge is inserted Pressure plate in a corresponding clamping device, whereupon the pressure plate through Applying a tension across the end of the print stretched around the outer circumference of the plate cylinder becomes. In particular for clamping and clamping, there are a large number of automated facilities known so that these steps, for example after Operation of a control element can be carried out remotely. An operator therefore has only the pressure plate in the corresponding pressure start clamping rail and then a corresponding control element that triggers the clamping to operate. Also inserting the printing end edge of the printing plate into the corresponding one Clamping device of the plate cylinder can be carried out automatically, so that this process takes place completely automatically.

DE 4 214 168 C2 describes a device for clamping printing plates onto the Plate cylinders of printing machines, in particular sheet-fed offset printing machines, in which a printing plate attached to the start of printing in the area of the printing end on a arranged in the cylinder channel clamping rail can be fastened, this clamping rail divided into several sections in the axial direction of the plate cylinder and one section each by means of a spring element for exerting the corresponding tensile force on the Printing end of the printing plate is provided. In this previously known facility are the individual clamping rail sections movable about two different swivel axes, see above that overall a movement of the tensioning rail section or that of the pressure plate Area almost in the circumferential direction of the plate cylinder is possible. By the spring elements assigned to the individual tensioning rail sections become the individual elements (i.e. the tensioning rail as a whole) from the front pit wall of the Plate cylinder swiveled or moved towards the center of the channel. To introduce a After opening the detection areas (clamping device), all of the printing plate ends Sections (i.e. the entire tensioning rail) against the spring force in the direction of the front Swinged pit wall and inserted the pressure plate end into the clamping gap. The clamping device is then actuated, after the pressure plate trailing edge has been gripped and the build-up of the tensile force by the corresponding spring elements results in an automatically increasing clamping force.

A different setting or exercise across the format width of the printing press tensile forces on the pressure plate not only serve to correct the unwinding between the blanket cylinder and impression cylinder elongations of the Printing material, especially influenced by the subject of dampening solution. A change caused by dampening solution on the substrate Print length (length of the print image on the substrate) has a negative effect Print end of the print image and must be corrected accordingly.

Corresponding corrective measures must therefore be taken here, DE 4 214 168 C2 mentioned above may consist in that the corresponding Preload forces for those acting on the individual clamping rail sections Spring elements are changed. In this case one has after winding and tensioning Pressure plate on the plate cylinder and after making the first print prints (a few machine revolutions) individual regulation of those exercised at the end of printing Clamping forces to take place.

A disadvantage of this procedure, briefly outlined above, is that, on the one hand the individual setting of the prestressing forces of the individual clamping rail sections associated spring elements is a very lengthy process (thread pitch). Furthermore, even after the used printing plate has been removed, the set one remains Preserve the spring elements, so that a newly fed and then tensioned Pressure plate with this individual (prestressed) setting of the spring elements is drawn around the outer circumference of the plate cylinder. One for a new print job The printing plate provided is therefore provided with a printing press that is larger than the format different tensile force drawn around the outer circumference of the plate cylinder, wherein this difference in traction across the format width of one from the previous Print job correction results. In this case, it cannot be ruled out that this correction resulting from the previous print job has a negative effect the print result affects especially the first prints, so that not only after Unclamping a used printing plate, the clamping device again on a total Must be reset (operated), but is also to be feared is this actuation or reset of the tensioning device in the starting position forget that a newly mounted printing plate over the format width with such very different tensile forces are stretched so that it remains (plastic) deformations.

DE 4 321 751 C1 describes a device for the precise clamping of printing plates known on the plate cylinder of printing presses, in which, in particular cooperating a hand tool with a tensioning rail according to the above-mentioned document is provided with an eccentric through which the on the pressure plate (whose End of printing) the tensile forces exerted can be individually corrected. The one on the tools attached eccentric acts in this way on an area of this clamping rail or the Clamping rail sections that in particular those exerted on the printing end of the printing plate Tractive forces can be increased. The pressure plate can therefore in certain sections be elongated in a defined manner, the force required to elongate them exclusively is applied during the operation of the hand tools. After application this over the format width of the printing machine in sections elongation of the printing plate again only the spring forces act on the pressure plate. This device has the advantage over the pressure plate clamping device mentioned at the outset that after unclamping a used and in particular individually stretched sections Printing plate a new printing plate again with the same across the format width of the machine Clamping forces is drawn around the outer circumference of the plate cylinder.

A disadvantage of the last-mentioned correction device, however, is that this means Only use hand tools to lengthen the pressure plate in sections to let. It is therefore not possible to use a printing plate in particular only in a few sections relieve the tensile forces with regard to the tension forces exerted on their pressure end to reduce in sections to the end of the printing plate.

The object of the present invention is therefore a device according to the preamble of claim 1 to expand in such a way that too large while avoiding the exercise Tensile forces on the printing plate an individual correction of the printing end of the Pressure plate exerted tensile forces, in particular when the section is executed Clamping rail is possible and also in an automated printing plate clamping device an existing correction when changing the printing plate is automatically canceled is so that a new printing plate is initially more even with the format width or uniform tensile force can be spanned.

This problem is solved by the characterizing features of claim 1. Further training the invention emerge from the subclaims.

According to the invention it is provided that in particular the format width of the machine (of the plate cylinder) divided into several sections, which each one or more spring elements are assigned by at least one setting element, preferably designed as an adjusting screw against the clamping force for the pressure plate applied spring elements can be operated. That the tensioning rail sections or the adjustment element assigned overall to the tensioning rail is in this case the tensioning rail assigned so that this from a first, not on the tensioning rail or the Tensioning rail sections acting position (stand-by) pivoted into a working position and the corresponding correction forces after actuation on the tensioning rail or the tensioning rail section against the force of the spring elements applies. The on the pressure plate or the end of its pressure by the spring elements The tractive force applied can now be regulated individually, that is to say in particular in sections reducing the clamping force exerted on the pressure plate end become.

The adjusting element provided according to the invention, which in a first position does not Contact with the tensioning rail or the tensioning rail sections is preferred against the force of an associated spring (torsion spring) pivotable by one Axle mounted, such that the adjusting element against the spring force in the position for Apply the appropriate correction forces to the tensioning rail or the tensioning rail sections is to be pivoted. After the adjusting element according to the invention in the the position provided for correction has been pivoted, in particular under With the help of a tool (open-end wrench), the appropriate correction force on the provided clamping rail section can be set. After finishing printing the clamping rail is then moved to release the used pressure plate or Release all clamping rail sections towards the pressure plate (towards the pit wall of the plate cylinder assigned to the printing end), so that the setting element or elements, which previously engaged with the corresponding tensioning rail sections have been brought into their starting position (stand-by position) due to the tensioned spring forces be pivoted back so that the clamping of a new pressure plate for a next print job with a uniform output force, in particular without the corrections individually set in the previous print job. Should corrections are made again for the next print job the corresponding setting elements by pivoting into their working position and, if necessary necessary turning back the adjusting nuts, again in engagement with the tensioning rail or the tensioning rail sections can be brought.

The adjustment device according to the invention for exercising in particular over the format width sections of different tensile forces on a pressure plate over its pressure end preferably takes place with one tiltable about one or more pivot axes Tensioning rail use, which was explained above (DE 4 214 168 C2) is. However, the device according to the invention can also be used with all tensioning rails Find use where the force exerted to clamp a pressure plate is effected by prestressed spring elements, and for detecting the end of the print a new as well as to release the printing end of a used printing plate on the Pressure plate end to be moved, and in which after attaching (clamping) the The end of the pressure plate releases only those released by the prestressed spring elements Forces on the clamping rail or the clamping rail sections on the pressure plate end Act.

Fig. 1

die erfindungsgemäße Vorrichtung in ihrer Ausgangsstellung (Stand-by),

Fig. 2 - 4

das Betätigen der erfindungsgemäßen Vorrichtung zum Einstellen unterschiedlicher Spannkräfte,

Fig. 5 + 6

das Rückstellen der erfindungsgemäßen Korrekturvorrichtung beim Entspannen einer gebrauchten Druckplatte,

Fig. 7 - 9

eine Betätigungsvorrichtung für eine Spannschiene bzw. einen Spannschienenabschnitt, mit welcher die erfindungsgemäße Vorrichtung bevorzugt zusammenwirkt und

Fig. 10

eine Draufsicht auf zwei Spannschienenabschnitte mit der erfindungsgemäßen Vorrichtung sowie der Betätigungsvorrichtung gemäß der Figuren 7 bis 9.

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

Fig. 1

the device according to the invention in its initial position (stand-by),

Figs. 2-4

actuating the device according to the invention for setting different clamping forces,

5 + 6

resetting the correction device according to the invention when relaxing a used printing plate,

Fig. 7-9

an actuating device for a tensioning rail or a tensioning rail section, with which the device according to the invention preferably interacts and

Fig. 10

a plan view of two clamping rail sections with the device according to the invention and the actuating device according to Figures 7 to 9.

Fig. 1 shows a section of a plate cylinder 1 in the area marked with DE Printing. In an axially parallel pit 2, the pressure end DE is a tensioning rail 3 assigned, which in particular consists of several adjacent clamping rail sections exists (Fig. 10). The tensioning rail 3 or the individual tensioning rail sections are pivotable overall about at least one pivot axis 4, so that a clamping gap 5 within the tensioning rail 3 or the tensioning rail sections almost in the circumferential direction of the plate cylinder 1 can be moved.

Not shown in FIG. 1 are associated with the tensioning rail 3 or the tensioning rail sections Spring elements, by means of which the tensioning rail 3 or the individual tensioning rail sections about pivot axis 4 (or successively about several pivot axes) is pivotable such that a pressure plate 6 fastened in the clamping gap 5 the outer contour of the printing end DE of the plate cylinder 1 is stretched. The order Such spring elements for exerting the tensile forces on the tensioning rail 3 or more Tensioning rail sections are known per se and therefore do not require any at this point further explanation. Furthermore, in the clamping rail 3 or in the individual next to each other lying and over the format width of the printing press (the plate cylinder 1) extending clamping rail sections arranged clamping devices through which to attach a printing plate 6 in the clamping gap 5, the printing end of the printing plate 6 can be attached is.

First of all, for a better understanding of the invention, that of the tensioning rail 3 or the actuating device 7 assigned to the plurality of tensioning rail sections, through which the clamping rail 3 or the clamping rail sections for releasing a used printing plate or to clamp a new printing plate against the Spring force of the spring elements, not shown, is pivotable. Parallel to the tensioning rail 3 or the several clamping rail sections pivotable about the common pivot axis 4 extends in the pit 2 of the plate cylinder 1 at the bottom of the Pit shaft 8 rotatably mounted several times, which according to the section by section the tensioning rail 3 a plurality of levers 9 with attached to their pivotable ends has rotatably mounted rollers 10 (Fig. 6-9). These roles 10 also act the area of the tensioning rail 3 or the tensioning rail sections facing away from the printing end DE attached contours 11 together like a curve control.

7 is for receiving a new printing plate mounted on the plate cylinder 1 6 the tensioning rail 3 or the individual tensioning rail sections by complete Swiveling back of the shaft 8 together with the lever 9 and the rollers 10 released in such a way that the tensioning rail 3 or the entirety of the tensioning rail sections one through the Force takes the defined end position of the spring elements, not shown. This end position 7 can be defined in particular by stops, not shown.

After the end of the pressure plate 6 has been brought into a defined position, this is done by pivoting the shaft 8 together with the levers 9 attached thereto and the rollers 10 in a direction of rotation counterclockwise, the pivoting of the tensioning rail 3 or the clamping rail sections about the pivot axis 4, so that the end of the pressure plate 6 in the open clamping gap 5 (the corresponding clamping device was previously actuated) is introduced (Fig. 8).

After actuating the clamping device, not shown, after the end of Pressure plate 6 is fixed in the clamping gap 5, the shaft 8 is relieved, so that the Clamping rail 3 or the entirety of the clamping rail sections by the force of not shown spring elements for tensioning the pressure plate 6 swings back. Fig. 9 shows the pressure plate tensioned by the tensioning rail 3 or the tensioning rail sections 6.

The device according to the invention consists according to the representations of FIGS. 1 to 5 and FIG. 10 from one or more of the tensioning rail 3 or the tensioning rail sections in a corresponding number of assigned control elements 12, which are fixed to the cylinder supported pivotable about the shaft 8 of the actuating device 7 of the tensioning rail 3 are stored. Each actuating element 12 is thus supported in a cylinder-fixed manner and pivotable about in particular, an axis mounted parallel to the axis of the plate cylinder. The invention provided actuator 12 is also a prestressed by the force Spring 20, which is placed around the shaft 8 of the actuating device 7 as a torsion spring is pivoted into a so-called stand-by position according to FIG. 1, this position is defined by a cylinder-fixed stop 13.

The actuating element 12 according to the invention consists of a shaft 8 in the manner of a socket comprehensive joint part 14, in which is inserted in a corresponding bore Threaded bolt 15 sits longitudinally movable, which protrudes from the joint part 14 and to the tensioning rail 3 or the tensioning rail sections facing end is executed (Fig. 1). On the threaded bolt 15 is a nut 16, for example designed as a hexagon or knurled nut, which is in turn in one located in the joint part 14 slot 17. The outside diameter of the nut 16 is larger than the width of the hinge part 14, so that the nut 14 for example can be turned using an open-ended wrench. By twisting the over the flanks of the slot 17 prevented from axial movement nut 16, the threaded bolt 15 more or less turned out of the hinge part 14.

Figures 2 to 4 show the use of the actuator according to the invention. For Use of the control element according to the invention, that is to say the tensioning rail 3 or a or several sections of the tensioning rail 3 with the pressure plate 6 clamped with respect To regulate the tensile forces exerted on the pressure plate 6 is first the actuating element 12 against the spring 20 shown in Fig. 10 (torsion spring) from the in Fig. 1 shown stand-by position pivoted a bit into the pit 2 of the plate cylinder 1. On the side facing away from the printing end DE of the plate cylinder 1 The tensioning rail 3 or the tensioning rail sections has the tensioning rail 3 or Tensioning rail sections each have a depression 18, which with the crowned end of the Threaded bolt 15 of the actuator (s) 12 cooperates. After swinging in of the control element or elements 12 from the stand-by position according to FIG. 1 in the 2, for example, the nut 16 is turned by hand until the crowned end of the threaded bolt 15 with the depression 18 of the tensioning rail 3 or Clamping rail sections comes into contact (Fig. 3). Now becomes the nut 16 of the actuator 12 rotated further to unscrew the threaded bolt 15, so the threaded bolt exercises 15 via the articulated part supported on the shaft 8 such a force on the Clamping rail 3 or the respective clamping rail section, so that the clamping rail 3 or this clamping rail section is displaced in the direction of releasing the pressure plate, thus the tensile force exerted by the spring element, not shown, on the pressure plate 6 is reduced accordingly. This pivoting of the tensioning rail 3 or the tensioning rail section to reduce the tensile force on the pressure plate 5 is in Fig. 4 by the dashed position of the tensioning rail 3 or of the respective tensioning rail section indicated.

To change a used pressure plate 6, the tensioning rail 3 or several will now be used Tensioning rail sections through the actuating device 7 from one in the figures 3, 4 and 9 shown position pivoted towards the end of printing DE, which as before explained above, by pivoting the shaft 8 and on the contours 11th the tensioning rail 3 or the tensioning rail sections acting rollers 10 causes becomes. The tensioning rail 3 or the tensioning rail sections are thus counter to the Force of the spring elements, not shown, pivoted toward the end of the print DE. At the Swiveling the tensioning rail 3 or the tensioning rail sections to the printing end DE is at the same time the crowned end of the threaded bolt 5 previously for correction used control elements 12 through the cooperating depressions 18 the respective sections of the tensioning rail 3 released, so that now by the force of the springs 20 assigned to the control elements 12 set the control elements 12 into the stand-by position pivot back according to FIG. 1. The pivoting back of the control element or elements 12 when pivoting the tensioning rail 3 or the tensioning rail sections by the actuating device 7 show in particular FIGS. 5 and 6. The stand-by position of the control element or elements 12 is defined by cylinder-fixed stops 13.

As can be seen in the illustration according to FIG. 5, one in one after pivoting back previous printing process for corrections required adjusting element 12 of the threaded bolt 15 correspondingly far from the joint part 14 in accordance with the correction made previously turned out. The maximum length by which the threaded bolt 15 from the Joint part 14 can be unscrewed, is chosen such that the end of the Threaded bolt 15 of an actuator 12 in the stand-by position not out of the pitch circle of the plate cylinder protrudes in order not to match the corresponding components of the Plate cylinder 1 interacting blanket cylinder or the rollers of the ink or dampening system to collide. Around the control element 12 according to FIG. 5 for correction processes To use it again in a next printing process, the threaded bolt 15 can only be turned back in by the nut 16 by a certain amount then after having previously clamped a new printing plate again by swiveling the Stellementes from the stand-by position (Fig. 1) again in contact with the tensioning rail 3 or the respective clamping rail section (depression 18) to be brought.

10 shows the arrangement of two or more sections of a tensioning rail 3 in the pit of a plate cylinder, not shown. The individual sections of the tensioning rail 3 are each mounted at a distance from one another on the bottom of the pit 2 Carriers 19 arranged pivotally. The individual carriers 19 also serve the mounting of the shaft 8 of the actuating device 7 for tensioning or for releasing a plate, not shown. The control elements 12 provided according to the invention are each adjacent the levers 9 with the rollers 10 pivotable on the shaft 8 stored assigned. Each actuator 12 is a seated on the shaft 8 and this spring 20 looping in several turns assigned as a torsion spring, wherein one end of the torsion spring (spring 20) is supported on a carrier 19 and that in each case other, biased end of the torsion spring (spring 20) in a manner not shown acts on the joint part 14 of the actuating element 12 in order to move the actuating element 12 into the position shown in FIG shown and pivoted by the cylinder-fixed stop 13 stand-by position.

Reference list

1

Plate cylinder

2nd

pit

3rd

Tensioning rail (tensioning rail section)

4th

Swivel axis (clamping rail 3)

5

Clamping gap

6

printing plate

7

Actuating device (tensioning rail 3)

8th

wave

9

lever

10th

role

11

contour

12th

Actuator

13

attack

14

Joint part

15

Threaded bolt

16

mother

17th

slot

18th

Sinking

19th

carrier

20th

Spring (torsion spring)

DE

End of printing

Claims (6)

1. Adjustment device for printing plates on the plate cylinders of printing presses, particularly offset sheet printing presses, with a tensioning rail (3) particularly one divided into sections, of which the region receiving the printing plate is arranged movably substantially in the peripheral direction of the plate cylinder (1) and spring elements are fitted to the tensioning rail applying the pulling force for the printing plate, characterised in that fitted to the tensioning rail (3) or the tensioning rail sections is at least one adjustment element (12) maintained by the force of a spring (20) in a position without contact relative to the tensioning rail (12) mounted swivellably and supported fixed with respect to the cylinder, which can be brought into contact with the tensioning rail (3) counter to the force of the spring (20) in order to diminish the pulling forces exerted by the spring elements on the printing plate (6).
2. Adjusting device according to Claim 1, characterised in that in the case of division of the tensioning rail (3) into several tensioning rail sections, an adjusting element (12) is fitted to each section.
3. Adjusting device according to Claim 1 or 2, characterised in that the adjusting element(s) (12) are mounted swivellably around an axis running parallel to the axis of the plate cylinder (1).
4. Adjusting device according to one of the preceding Claims, characterised in that the adjusting element(s) (12) are mounted on a shaft (8) of an actuation device (7) fitted to the tensioning rail (3) or the tensioning rail sections.
5. Adjusting device according to one of the preceding Claims, characterised in that the adjusting element (12) consists of a joint piece (14) mounted swivellably with respect to the plate cylinder (1) with a threaded pin guided axially movably therein, on the threaded shaft of which a nut (16) secured against axial movement is threaded and the end of the threaded pin (15) projecting out of the joint piece (14) cooperates with a part of the tensioning rail (3) or a part of the tensioning rail section.
6. Adjusting device according to one of the preceding Claims, characterised in that the tensioning rail (3) or tensioning rail sections in each case have on the side away from the print end (DE) niches (18) which cooperate with the swivellable ends of the respective adjusting elements (12).

Images