JPH10100380A - Form plate tightener - Google Patents

Abstract

PROBLEM TO BE SOLVED: To expand or contract an end part of a form plate in the circumferential direction or axial direction of a plate cylinder, as required, by providing a holding element with a strip which acts on the lower surface of the form plate and is adjustable in the circumferential direction or axial direction of the form plate. SOLUTION: Upper surface of a strip 10 facing the lower surface of a form plate extends in a plane where the end part of the form plate being held by a holding pin 5 or the hook 6 thereof extends. One clamp strip 11 can be secured, as required, along with each half part of the strip 10 through a plurality of screws 12 and the end part of the plate is clamped between the corresponding faces of the clamp strip 11 and the strip 10 by tightening the screw 12. After the end part of the plate is clamped between the strip 10 and the clamp strip 11, the strip 10 is adjusted in the circumferential direction through an adjusting screw 13 supported on a support 3 depending on a determined required correction amount.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a printing plate having a leading edge fixed against a force of a spring disposed at a printing end portion. Elongation of the print carrier in a printing press, in particular in a plate cylinder of a sheet-fed offset printing press, of a type which is movable in a direction and in a transverse direction and is fixed in a plurality of holding elements cooperating with openings formed in the plate. The present invention relates to a plate tightening device for compensating for the following.

[0002]

2. Description of the Related Art In a sheet-fed offset printing press, a printing plate to be fixed on a plate cylinder is first fixed to a clamping device provided at a printing start end, and the plate cylinder is rotated in a forward direction. Thus, it is stretched on the outer peripheral surface of the plate cylinder. Then, the rear end of the printing plate is fixed to a correspondingly arranged device. In such a case, a fixing device that also clamps and holds the printing end portion of the plate is widely used. In the case of such a plate fixing device,
The correction of the position of the plate with respect to the plate cylinder supporting the plate must be effected by correspondingly moving the fixing devices arranged at the printing start and the printing end.

A printing start end of a printing plate is fixed to a front tightening strip, and the tightening strip is arranged on a circumferential surface of the plate cylinder in such a manner as to be movable in both the circumferential direction and the axial direction with respect to the plate cylinder. A device for stretching a printing plate is known from DE-A-420 25 276. The rear end of the printing plate has perforations in the form of punch holes which are axially separated from one another, said perforations cooperating with a plurality of pin elements for fixing the printing plate. In operation, the pin element is movably mounted in the circumferential direction of the plate cylinder as well as in a direction perpendicular thereto, that is, in the axial direction of the plate cylinder, and is connected to a spring element. The fixing of the printing plate in a printing cylinder equipped in this way involves first fixing the leading edge of the printing plate in the corresponding tightening strip, and then drilling the printing plate after stretching the printing plate on the outer circumferential surface of the printing cylinder. This is achieved by engaging the part with a hook-shaped spring-movable pin element. The leading clamping strip is then moved to a zero position (printing start) in the direction of the front wall of the barrel groove by a suitable actuation control of an adjusting motor arranged on the clamping strip, whereby it can be spring-moved. The supported pin elements are clamped to hold the printing end of the printing plate. In this case, the known device has the advantage that the printing plate thus fixed on the outer peripheral surface of the printing drum can be modified by the movement of the front tightening strip, even during the operation of the machine, to correct the circumferential register and the lateral register. Therefore, it has the advantage that it can be moved for correcting the oblique register. The disadvantage in this case, however, is that it is not easy to correct the register deviations which are first noticed at the printing end of the printed sheet, in particular due to the stretching of the print carrier, and in particular by a corresponding stretching of the printing plate. That is not possible.

A printing plate correction device for guaranteeing the elongation of the print carrier is known from DE 4244279, in which a printing plate bent at the ends is used. It is held between two clamping surfaces which can move relative to each other and is stretched around the outer peripheral surface of the plate cylinder entirely by the forces of a plurality of springs. In this device, an elongate shaft is provided which penetrates the cylinder groove of the plate cylinder, and has a plurality of tightening elements which are respectively supported in a non-rotatable parallel manner,
By means of the clamping element, it is possible to introduce a certain degree of extension of the printing plate end. In this device, a change in the printed image can be obtained by stretching the printing plate in a clamped state.

However, a disadvantage of the known device is that, by virtue of its method of clamping or fixing the printing end of the printing plate, a corresponding movement of the fastening strip arranged at the printing start causes a corresponding printing of the plate. The position of the printing plate on the outer peripheral surface of the cylinder cannot be changed as a whole. The clamping device arranged at the printing end can certainly follow the plate movement introduced via the printing start to a certain extent, but it does follow plate changes in the axial direction relative to the plate cylinder. I can't.

A method and a device for correcting trapezoidal register deviations are known from DE 42 26 192, in which the printing ends of the printing plates are again movable relative to one another. Fixed between two clamping surfaces. The initial proofing is followed by the detection of a register deviation, and then by changing the lateral distance of the two trailing edge portions of the printing plate for clamping, the extension or compression of the printing plate end is reduced at the printing end. This is done to minimize or completely compensate for the previously identified register deviation. In that case, before the correction, the two printing plate trailing edge portions provided for changing the lateral distance are loaded with an additional clamping force, and during the correction the central portion of the printing plate trailing edge However, in this clamping area, the plate is loaded with a clamping force which still allows the plate to be stretched, and in order to compensate for the circular deformation of the plate, a corresponding plate trailing edge is additionally provided in the circumferential direction. Adjusted. However, in this known device and in the method described in connection therewith, the outer periphery of the plate cylinder during the operation of the printing press is obtained by exclusively clamping the plate trailing edge, i.e. the printing plate trailing edge. There is a disadvantage that the printing plate cannot be moved along the surface.

[0007]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to avoid the above-mentioned disadvantages of the prior art and to extend or compress the end of the printing plate in the circumferential direction of the plate cylinder or in the axial direction of the plate cylinder as required. It is an object of the invention to improve a device of the type described in the preamble of claim 1.

[0008]

According to a first aspect of the present invention, a holding element configured as a holding pin includes a lower surface of a printing plate. And a strip which can be adjusted in the circumferential and / or lateral direction of the plate cylinder and which is provided with a clamping strip for clamping the end of the plate if necessary. Is that it can be mounted.

[0009] Advantageous configurations of the invention are obtained by the measures as set forth in the claims.

In summary, according to the invention, at least a plurality of holding elements which are movable in the circumferential direction and in the lateral direction of the plate cylinder and which clamp the plate end by means of a spring force, in particular configured as pins, In addition, strips are provided which are movable in the circumferential direction and / or in the lateral register direction of the plate cylinder and which serve as underlays of the printing plate end which are fixed by holding elements and, if necessary,
In particular, when extension and / or compression is required under the influence of a dampening agent and / or when the rear edge of the plate cylinder needs to be deformed in the circumferential direction of the plate cylinder, a clamp strip serves as the underlay. Can be fixed to the strip. Since the underlay or strip, which can be extended to the clamping device, is divided over the entire width of the plate cylinder, after suitably clamping the trailing edge of the plate, the trailing edge of the plate extends or compresses its width. can do. Also, cushion-shaped or barrel-shaped image distortions at the printing end can be corrected by a corresponding deformation of the print carrier.

[0011]

Next, an embodiment of the present invention will be described in detail with reference to the drawings.

The plate cylinder 1 has a cylinder groove 2 parallel to the axis at a part of its outer periphery. At the bottom of the body groove 2, a support 3, which is configured as a strip, is arranged over the entire length of the body groove 2, and thus over the entire width of the plate cylinder 1. A plurality of spherical joints 4 are mounted at intervals in the axial direction of the plate cylinder 1 so as to face the wall. A retaining pin 5 is movably supported on each spherical joint 4 in both the circumferential register direction and the lateral register direction of the plate cylinder 1.
The end of the holding pin 5 is provided with a hook 6 cooperating with a fixing hole 7 provided at a printing end of a printing plate 8 stretched on the outer peripheral surface of the printing cylinder 1. Each retaining pin 5 is provided with a spring element 9 acting on the retaining pin via a drawbar, which spring element is supported by the support 3 as shown in FIG. ing. The printing end of the printing plate 8 is pulled around the outer peripheral surface of the printing drum 1 via the hook 6 by a spring element 9 arranged on the holding pin 5. Due to the mobility of the retaining pins 5, the printing end of the printing plate 8 can be moved in accordance with the register correction introduced via the front clamping strip, not shown in FIG. .

According to the invention, a strip 10 divided at the center of the plate cylinder is movably mounted on the support 3 in the circumferential and lateral directions of the plate cylinder 1. The upper surface of the strip 10 facing the lower surface of the printing plate 8 is in this case the printing plate 8 held by the holding pins 5 or the hooks 6 of the holding pins.
Extend in the plane in which the end of. If necessary, one clamping strip 11 can be fixed together with each half of the strip 10 via a plurality of screws 12, in which case the clamping of the screws 12 causes the printing plate 8 to be fastened.
Are clamped between corresponding surfaces of the clamp strips 11 and 10. After the end of the printing plate 8 has been clamped between the strip 10 and the clamping strip 11, the strip 10 is
Is adjusted in the circumferential direction via an adjusting screw 13 supported by the support 3.

As can be seen from FIG. 3, the tightening device of the present invention comprises:
Strip 1 divided at the center of the plate cylinder 1 not shown
0 and a clamp strip 11 that can be attached to each strip half as required. A total of two adjusting screws 13 are provided for each half of the strip 10 to initiate a correction operation (extension or compression) to be performed in the circumferential direction of the plate cylinder 1. Therefore, the printing end portion of the printing plate 8 stretched around the outer peripheral surface of the printing drum 1 may be extended strongly in the central region as necessary, or the edge region may be extended more than the central region. It can be stretched.
In order to be able to correct the printing width at the printing end, a further adjusting screw 14 consisting of two screw bolts is additionally provided between the strips 10 on the left half of the printing cylinder and on the right half of the printing cylinder. And one screw bolt of the adjusting screw 14 has a right-hand thread into a female screw hole of one strip 10, and the other screw bolt is a female screw of the other strip 10. It has a left thread threaded into the hole. Therefore, the strip 1 for clamping the end of the printing plate 8
0 and the clamping strip 11 can be adjusted at a distance from one another by turning the adjusting screw 14 accordingly.

As shown in FIG. 1, the adjusting screw 13 is screwed through a hole formed in a leg of the strip 10 disposed on the upper surface of the support 3 and engaging the support 3 from behind. And is supported by the support 3 at an end. Furthermore, as can be seen from FIG. 2, in order to guide the strip 10 with respect to the support 3, screws 15 passing through holes drilled in the support 3 are provided with internal threads formed in the support 3. Screwed into the hole, the screw 15 holds the strip 10 in its basic position against the support 3 via the associated spring 16 (disc spring) when the adjusting screw 13 is not actuated.

FIG. 2 shows a fixing method for fixing a clamp strip 11 that can be mounted as required to the strip 10. The clamp strip 11 has a long hole-like opening 17 (ring portion) corresponding to the number of screws 12 provided for fixing the clamp strip 11 to the strip 10. For the insertion of the strip 11, one end of the opening 17 is enlarged corresponding to the diameter of the screw head of the screw 12. After mounting the clamp strip 11 and laterally shifting the clamp strip 11 to the position shown in FIG. 2, by turning the screw 12, the clamp strip 11 separates the clamp strip 11 from the strip 10. It is tightened to clamp the printing plate 8 in between. Then, the correction operation described with reference to FIG. 3 is performed by turning the adjustment screws 13 and 14. After taking the necessary corrective actions and printing the order,
Clamp strip 11 by loosening screw 12
Is again removed from the strip 10, so that the printing plate 8 again cooperates exclusively with the spring-loaded bearing pins 5 for automatically stretching the printing plate 8.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a plate holding device disposed at a printing end of a plate cylinder and a tightening device according to the present invention.

FIG. 2 is a plan view of the tightening device of the present invention and a fixing mechanism of a tightening strip provided in the tightening device.

FIG. 3 is a plan view of a correcting device divided at the center of the trunk and an adjusting unit thereof.

[Explanation of symbols]

1 plate cylinder, 2 drum groove, 3 support, 4
Spherical joint, 5 retaining pin, 6 hook, 7
Perforation, 8 plate, 9 spring element,
10 strips, 11 clamp strips,
12 screws, 13, 14 adjustment screws, 15
Screw, 16 disc spring, 17 opening

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Gernaut Mosel Germany Ruedesheim Flechtaweg 24 a

Claims (6)

[Claims] At the printing end, a printing plate with a fixed leading edge is movable circumferentially and laterally against the force of an arranged spring and cooperates with an opening formed in the printing plate. In a clamping device for a printing plate for correcting the elongation of the print carrier in a plate cylinder of a printing press of the type fixed to a plurality of holding elements, a holding element (5) configured as a holding pin includes a plate. A strip (10) is provided which acts on the lower surface of the plate (8) and is adjustable in the circumferential and / or lateral direction of the plate cylinder (1), said strip comprising:
Clamping device for a printing plate, characterized in that a clamping strip (11) can be mounted to clamp the terminal end of the printing plate (8) as required. 2. A strip (10) which is adjustable in the circumferential and / or lateral register direction and a clamp strip (11) which can be mounted on said strip if required.
2. The tightening device according to claim 1, wherein the device is divided over the entire width of the plate cylinder. 3. The printing drum according to claim 1, wherein the strip is adjustable in the circumferential direction of the printing drum via an adjusting screw fixedly supported on the printing drum. Tightening device. 4. The clamping strip (11) is connected to the strip (1) via a plurality of screws (12) as required.
4. The tightening device according to claim 1, which can be fixed to 0). 5. A strip (10) is divided at the center of the plate cylinder (1), and each of the divided strips is provided with a clamp strip (11). Or clamp strip (1
5. The tightening device according to claim 1, wherein an adjusting means for changing the distance between the strips or the clamp strips in the axial direction of the plate cylinder is provided between the strips. 6. The adjusting means for changing the mutual spacing of the strips (10) or the clamping strips (11) is provided as an adjusting screw (14) having a right-hand threaded screw bolt and a left-hand threaded screw bolt. 6. The tightening device according to claim 5, wherein the device is configured.