Device for feeding printing plates to a plate cylinder of a printing press

Abstract

Device for feeding printing plates to a plate cylinder of a printing press, comprising a pivotably arranged guide element, a stop for pre-aligning the printing plate and a locking element (38) for securing the printing plate (28) on the stop (39), wherein the locking element (38) is pivotably arranged under the force of a spring (36), characterized in that the locking element (38) has a control element (34) with a control surface (35) and that this is in operative contact with a control roller (32).

Description

In a device for feeding printing plates to a plate cylinder of a printing press, provision is made for a new or already used printing plate to be prealigned before the printing plate is fed. DE 44 04 558 A1 discloses a device for supplying printing plates, in which a printing plate is pre-aligned by means of a stop outside of the plate cylinder. Here, the pressure plate is supported with its front edge on the stop. In particular, a used printing plate usually has a curvature caused by the plate cylinder and therefore tends to slip off the stops. The invention has for its object to provide a device that secures the position of the pressure plate on the stop. The object is achieved according to the invention by the features of claim 1. It is a particular advantage of the invention that a headband is provided to fix the pressure plate on the stop. As a result of this measure, the printing plate, in particular the leading edge of the printing plate, can be fed to the plate cylinder exactly and without any problems. In a particular embodiment, it is provided that the headband is pivotally mounted. This measure allows the front edge of the printing plate to be unlocked and released. Further advantages are described in the subclaims. An embodiment of the invention is illustrated in the drawings and we described below. It shows: 1 a sheet-fed rotary printing machine in section in a schematic representation, 2 shows a section through the printing plate feed device according to the invention. A sheet 7 processing machine, z. B. a printing press 1, has a feeder 2, at least one printing unit 3 or 4 and a delivery 6. The sheets 7 are removed from a sheet stack 8 and fed to the printing units 3 and 4 individually or in shingles via a feed table 9 . In a known manner, these each contain a plate cylinder 11, 12 and rubber blanket cylinders 15, 20 cooperating therewith. The plate cylinders 11 and 12 each have a clamping device 13, 14 for fastening flexible printing plates. In addition, each plate cylinder 11, 12 is assigned a device 16, 17 for the semi-automated or fully automatic changing of printing plates. The stack of sheets 8 rests on a stack plate 10 that can be raised in a controlled manner. The sheets 7 are removed from the top of the stack of sheets 8 by means of a so-called suction head 18, which has, among other things, a number of lifting and trailing suction cups 19, 21 for separating the sheets 7. In addition, blowing devices 22 are provided for loosening the upper sheet layers and feeler elements 23 for stack tracking. A number of lateral and rear stops 24 are provided for aligning the stack of sheets 8, in particular the upper sheets 7 of the stack of sheets 8. The printing plate changing device 16; 17 is arranged on a guard 26 which is suspended in front of the cylinders and rollers of the printing unit 3 and 4, respectively. The guard 26 has a pivotally arranged guide element 27 which moves from a waiting position for receiving a new or used printing plate 28 into an operating position on the plate cylinder 11; 12 is movable. The guide element 27 has two interacting transport rollers 29 , 31 and a control roller 32 . The control roller 32 is attached to the guide element 27 and is in operative contact with a control element, e.g. B. a control surface 35 of the control element 34 . The control 34 is also pivotable on Protection 26 stored. A spring 36 supported on the guard 26, e.g. B. tension spring, engages one end of the control element 34 and pulls it about a pivot point 37 against the control roller 32 . The control element 34 has a locking element 38, e.g. an upwardly opening hook or retaining clip. A stop 39 attached to the guard 26 serves to pre-align the pressure plate 28 . Preferably, at least two stops 39 are provided across the format width, which are designed as register pins and correspond to recesses in the printing plate 28. A provided on the stop 39 and pre-aligned pressure plate 28 is in this case surrounded by the bracket 38 from below and secured by the upwardly directed part of the bracket 38 against slipping in the direction of the plate cylinder 11. To feed the pre-aligned printing plate 28, the guide element 27 is pivoted by means of a drive, not shown, about a bearing point 41 close to the plate cylinder 11. here the printing plate 28 is held between the transport rollers 29 , 31 . So that the front edge of the printing plate can now slide off the stops 39, the retaining bracket 38 is pivoted downwards about the pivot point 37. Here, the control roller 32, which is in contact with the control surface 34, releases the control element 34, which is under the force of the spring 36, and which is pivoted away—clockwise—together with the retaining clip 38. When the guide element 27 pivots back into the waiting position, the control roller 32 pushes the control element 34 and the retaining bracket 38 back into the receiving position for a new printing plate 28 in the reverse order. 1 printing press 2 investor 3 printing unit 4 printing unit 5 6 boom 7 bow 8th stack of sheets 9 infeed table 10 stacking plate 11 plate cylinder 12 plate cylinder 13 pressure plate attachment 14 pressure plate attachment 15 16 printing plate changer 17 printing plate changer 18 suction head 19 lifting sucker 20 21 tow sucker 22 blowing device 23 tactile element 24 attack 25 26 Protection 27 guiding element 28 printing plate 29 transport roller 30 31 transport roller 32 control roll 33 34 control 35 control surface (34) 36 Feather 37 Pivot (34) 38 locking element 39 attack 40 41 Pivot (27) QUOTES INCLUDED IN DESCRIPTION

[0018] This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Patent Literature Cited - DE 4404558 A1

[0002]

Claims

[1] Device for feeding printing plates to a plate cylinder of a printing press, with a pivotably arranged guide element and a stop for pre-aligning the printing plate, characterized in that a locking element (38 ) is provided for securing the printing plate (28 ) on the stop (39 ). [2] Device according to claim 1, characterized in that the locking element (38 ) is pivotably arranged. [3] Device according to claim 2, characterized in that the locking element (38 ) is arranged to pivot under the force of a spring (36 ). [4] Device according to claim 3, characterized in that the locking element (38 ) has a control element (34 ) with a control surface (35 ) and that this is in operative contact with a control roller (32 ). [5] Device according to claim 4, characterized in that the control roller (32 ) is arranged on the guide element (27 ) for the pressure plate (28 ). [6] Device according to one of the preceding claims, characterized in that it is arranged on a guard (26) which covers the cylinder and roller area of ​​a printing press. [7] Sheet-fed rotary printing press with a device according to one of the preceding claims.

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