EP0144334A1

EP0144334A1 - Attachment for printing plate.

Info

Publication number: EP0144334A1
Application number: EP84901345A
Authority: EP
Inventors: Reiner Roosen
Original assignee: Individual
Current assignee: Individual
Priority date: 1983-06-11
Filing date: 1984-03-29
Publication date: 1985-06-19
Also published as: DE3464472D1; NO850489L; AU2740084A; FI850404L; FI72466C; FI72466B; WO1984004900A1; DK39785D0; FI850404A0; AU569204B2; DK39785A; JPS60501549A; DE8317151U1; EP0144334B1; US4604811A

Abstract

Fixation (70) pour plaques d'impression à appliquer sur le cylindre d'impression (72) d'une machine de flexographie, permettant l'ajustement précis de différentes plaques d'impression les unes par rapport aux autres. A cet effet, la fixation (70) comporte un rail (76) applicable de manière libérable sur le cylindre, respectivement les cylindres (72), qui présente de son côté des saillies (78) entrant en interaction avec des évidements pratiqués sur les plaques d'impression. En vue d'un positionnement simple et précis, la fixation (70) peut s'appuyer par centrage automatique sur le, respectivement les arbres de cylindre d'impression (102).Fixing (70) for printing plates to be applied to the impression cylinder (72) of a flexographic machine, allowing the precise adjustment of different printing plates relative to each other. To this end, the fixing (70) comprises a rail (76) releasably applicable on the cylinder, respectively the cylinders (72), which for its part has projections (78) interacting with recesses made on the plates. printing. For simple and precise positioning, the attachment (70) can be supported by automatic centering on the, respectively, the impression cylinder shafts (102).

Description

* ^'

Bracket for a printing plate

The invention relates to a holder for printing plates to be applied to printing cylinders of a flexographic printing press. 5

Flexographic printing is a rotary high-pressure process for, for example, imprints on packaging, forms, brochures or the like, in which printing plates consisting of photopolymers or rubber are preferably glued onto the printing cylinders 10.

If you want to print inscriptions or, for example, illustrations in different colors on the same material in a simple way, different clichés are used - the basic

15 can also be applied to various printing cylinders in order to be able to carry out the printing work. However, in order for the desired assignment to one another for the printing work with regard to the prints originating from the various clichés, it must be ensured that the clichés are clearly related to one another.

20 position in order on the printing cylinders. Often one makes use of elaborate sticking-on devices which make it possible to assign one color to another by means of a mirror device or other optical devices. This type of cliché assembly is not only very complex, but also involves considerable

25 sources of error. It is therefore an object of the present invention to provide a holder for printing plates to be applied to printing cylinders of a flexographic printing machine, which enables various printing plates to be applied in a precise position on the printing cylinders of the flexographic printing press, so that the finished printing work is error-free .

The object is achieved in accordance with the invention in that the holder u - comprises a rail which can be releasably arranged on the respective cylinder and which has projections or recesses for receiving the pressure plate. This bracket is attached to the printing cylinder when a new cliché or a new printing plate is to be glued to the printing cylinder. In this case, there must always be a clear orientation with respect to the pressure cylinder axis. This is ensured according to the invention by the holder. After this has taken place, the section which interacts with the rail is detached from the rail in order - after the holder itself has been removed - to also glue this region onto the printing cylinder. The clichés are applied accordingly to the other printing cylinders, which have a clear orientation in the machine. This ensures that the individual printing plates are arranged with an exact fit to one another, so that the finished printing work has no undesired overlaps resulting from the individual clichés. So that the rail, which enables the printing plate to be arranged on the respective printing cylinder in an extremely simple and precise manner, runs parallel to the longitudinal axis of the printing cylinder without complex adjustment measures, it can be supported on the shaft of the cylinder and at least partially encompasses it. The rail is preferably U-shaped, so that the angled legs, which run at least partially along the end faces of the pressure cylinder, each have a recess adapted to the shaft. This can be, for example, the shape of a hollow cylinder cut on the shaft

i

OMPΪ v. ^{v;: i,} ° is put on. Of course, the rail section which interacts with the shaft can also partially encompass the shaft from below, in order in this way to enable the holder to be arranged on the pressure cylinder even more securely. According to a particularly noteworthy embodiment of the invention, the sections of the holder which run along the end faces of the cylinder each consist of scissor-shaped movable jaws which have mutually facing, preferably V-shaped recesses which extend from the pin or. the shaft of the cylinder are penetrated, while at the same time self-centering takes place. A spring force also acts between the jaws of each side section such that they are always moved toward one another, so that the shaft of the cylinder can thereby be clamped. Finally, a swiveling locking element can emanate from a jaw, which can be introduced into a recess in the other jaw, in order to immovably position the holder on the shaft when the rail is oriented in the correct position relative to the cylinder by means of the locking element, for example by tightening a nut. The cliché can then be applied in a precise position.

According to a particularly noteworthy inventive design, the holder is supported by centering elements on the shaft or the cylinder journal. Each centering element is preferably plate-shaped, runs parallel to the front end of the cylinder and has approximately a V-shaped recess which interacts with the shaft or the pin in sections. This causes self-centering. Since the centering elements have an unambiguous association with the rail aligning the printing plates on the printing cylinder and the main cylinder axis, this ensures in a simple manner that the printing plates can be arranged precisely on the printing cylinder.

In a further embodiment, the shaft is gripped by a clamping lever, via which a force in the direction of the centering element - L, -

can be generated. This results in the holder being clamped onto the shaft, so that the pressure plate can then be arranged without problems. The tensioning lever itself, which can simultaneously serve as a handle for the entire holder, is caused by a compression spring in a basic position lifted from the shaft and is moved in the direction of the shaft by means of a tensioning screw, preferably against the spring force. This movement is in the true sense a pivoting around a pin passing through the tensioning lever, which starts from the holder and whose axis runs parallel to the longitudinal axis of the rail.

Finally, according to a further embodiment, the rail itself can be detachably arranged on the holder and displaced to its longitudinal axis in order to increase the variability.

The rail itself can be aligned in the cylinder axis by means of auxiliary devices or have so-called orientation slots in its longitudinal direction, which are to be aligned on the markings present on the printing cylinder surface, so as to ensure that the holder is arranged in the correct position. Thereby it is guaranteed that on the bracket aligned on the printing cylinders to be applied clichés the exact orientation learn each other so that the printing work in the use of different cliches which are used successively for printing on one and the same material ^', learn the desired quality. Of course, with the help of the holder according to the invention, if only one printing cylinder was present, different printing plates could be applied one after the other in a precisely fitting manner.

If the rail preferably has projections to which recesses in an edge region of the printing plate are assigned, recesses provided in the clichés in the holder can of course also be assigned to recesses

O PI be. However, these projections must be chosen so small that they are not noticeable when printing.

As an alternative to this, projections can be detachably arranged on the printing cylinders themselves, which protrude from the cylinder surfaces for aligning the printing plates to be applied one after the other. After the pressure plates are attached to the cylinders, i.e. glued on, the projections can be removed again. In this case, the projections should preferably have a pin shape and at least in one section have an external thread which can interact with a thread embedded in the pressure cylinder. Of course, the printing cylinder can also have recesses for aligning clichés in the correct position, into which projections on the printing plates can then be introduced.

Further details, advantages and features of the invention result not only from the claims but also from the preferred exemplary embodiments shown in the drawing.

Show it :

ig. 1 a holder to be attached to a printing cylinder,

ig. 2 shows a further exemplary embodiment of a holder arranged on a printing cylinder in a side view and partially broken away,

ig. 3 shows a third embodiment in side view,

ig. 4 shows a front view of a section of the embodiment according to FIGS. 3 and

ig. 5 shows a sectional illustration along the line VV in FIG. , 1 shows an example of a printing cylinder 14 of a flexographic printing press with a removable holder 10 which is intended for aligning printing plates to be arranged on the printing cylinder 14. The holder 10 preferably has the shape of a rail 12, which has laterally angled end sections 20 and 22, which in turn interact with the shaft 18 of the pressure cylinder 14. In the exemplary embodiment in FIG. 1, sections 20 and 22 have hollow cylindrical sections 28 and 30, the inside diameter of which is adapted to the outside diameter of shaft 18. Accordingly, if sections 28 and 30 are placed on shaft 18, rail 12 is aligned in the longitudinal axis direction of printing cylinder 14. Sections 20 and 22 of rail 12 can also be designed differently, e.g. B. have a portion that engages around the shaft 18 from below.

The sections 20 and 22 run parallel or almost parallel to the end faces 26 of the printing cylinder 14 and can be attached to this by means of a fastening device such. B. a screw 24 can be positioned non-rotatably. So that the rail can assume a desired position not only parallel to the longitudinal axis of the cylinder 14, but also with respect to the peripheral surface, without extensive adjustment work, longitudinal slots 32 and 34 are provided, which extend in the longitudinal direction of the rail 12, that is to say parallel to the longitudinal axis of the Cylinder 14, run. The surface of the * printing cylinder 14 now has marking lines, not shown, to which the slots 32 and 34 are aligned. Then the holder 10 assumes the desired position relative to the cylinder 14 in order to be able to apply printing plates or clichés, not shown, which are then arranged with a precise fit on the printing cylinder 14 and in relation to further printing cylinders. For this purpose, the rail 12 in the exemplary embodiment has projections 16, which are assigned corresponding recesses on one edge of the pressure plate. In order to apply a pressure plate to the cylinder 14, the recesses are penetrated by the projections 16. This gives the cliché the perfect fit Alignment with the printing cylinder 14. The section of the printing plate located outside the rail can then be glued to the printing plate without difficulty. Then the section of the plate that interacts with the rail 12 is lifted off the cliché in order to be able to remove the holder 10. Finally, the corresponding section of the pressure plate is also pressed onto the pressure plate 14 and glued. If a material to be printed is now to be printed by means of a second cliché, the holder 10 is - as described above - applied to further printing cylinders of the flexographic printing press which are clearly oriented towards the printing cylinders 14, in order for the projections 16 to interact with the recesses of further clichés to let, which ensures that the other clichés to be used also have the exact fit on the printing cylinders, which is required that the finished printing does not show any undesired overlaps from the individual printing plates. The printing plates applied by means of the holder according to the invention then print in register.

2 shows a side view of a holder 38, which is arranged on the shaft 18 of the printing cylinder 14 precisely, but releasably. The holder 38 also comprises a rail 40 with projections 42 which can pass through recesses of a cliché, not shown. Jaws 46 and 48, which can be separated, run along the end faces (shown the end face 44 of the cylinder 14), which together form sections which function according to the elements 20, 22, 24, 28, 30 of the exemplary embodiment according to FIG. 1 correspond. The jaws 46 and 48, which are rotatable about the axis 50, have V-shaped recesses 52 and 54 in the regions facing one another, which, when put together, form a quadrangular shape and which have their boundaries 56, 58, 60 and 62 at the cylinder 14 mounted bracket 38 come to rest in sections on the core or the shaft 18. This results in self-centering, for which the jaws 46 and 48 are caused by spring force endeavor to keep the free area formed by the recesses 52 and 54 as small as possible. From the lower area of the jaw 46 there is also a locking element 64 which can be pivoted and can be introduced into a recess 66 of the jaw 48 in such a way that after the holder 38 has been aligned in a precise position on the cylinder 14 by means of the edge sections 68 or the like Acting element, the jaw 46 and 48 are tightened to abut the shaft 18 rotatably. This ensures that the holder 38 can no longer be rotated in an uncontrolled manner.

In the Fig. 3 to 5, a further embodiment of a holder 70 according to the invention is shown, which is intended to be positioned precisely on a printing cylinder 72 of a flexographic printing machine with respect to the longitudinal axis 74 of the cylinder 72. The bracket comprises a bar 76 which has projections 78 on which clichés are to be arranged in the manner described above. The strip 76 is slidably arranged on a wedge 78, which in turn preferably starts from a square tube 80 as a support. The slidability of the bar 76 takes place via a sliding block 82 which is embedded in the wedge 78 on the one hand and is received on the other by the rear of the bar 76. The bar 76 is preferably fixed in relation to the connecting tube 80 by means of a knurled screw 82. The displaceability of the bar 76 in relation to the support tube 80 has the advantage that the bar 76 and thus the cliché can be moved horizontally to the pressure cylinder 72.

A connecting plate 90 extends from the carrier tube 80 via pin 86 (only the left pin shown) on both sides of the end faces 88 of the pressure cylinder 72, to which in turn a centering element 92 and a tensioning lever 94 are fastened. Furthermore, the connection plate 90 has in the upper region a web 96 which runs parallel to or approximately parallel to the square tube 80 and is angled from the connection plate 90 and which is penetrated by a tensioning screw 98 for interacting with the tensioning lever 94.

OV.PI The centering element 92 now has a preferably V-shaped recess 100 which can be placed on the pin or the shaft 102 of the pressure cylinder 72. This results in self-centering. So that the exact alignment of the bar 76 and thus the cliché takes place in relation to the pressure cylinder 72, the centering element 92 can be adjusted with respect to the connecting plate 90 by means of an adjusting screw 104, so that when the positional alignment on the longitudinal axis 94 of the pressure cylinder 72 is achieved To be able to carry out pinning (indicated by reference numerals 106, 108).

As soon as the holder 70 is supported on the pin 102 by means of the centering elements 92, which extend on both sides of the end faces 88 of the pressure cylinder 72, the pin 102 is gripped by the tensioning lever 94, thereby ensuring that the holder 70 cannot be moved on the pin 102 is. For this purpose, the tensioning lever 94 is moved in the direction of the pin by means of the tensioning screw 98 in order to interact with a lower leg 110 on the underside or a cut on the underside of the shaft 102. The tensioning lever 94 is about a pin 112 pivotable and must be moved against a spring force exerted by a compression spring 114 in the direction of the pin 102 by means of the clamping screw 98; because in the normal position, the clamping lever 94 is pivoted away from the pin 102, so that it can also be used as a handle for the holder 70. ^"'

By means of the bracket 70 according to the invention can be applied 78 precisely positioned on the circumference of the printing cylinder 72 now clichés on the bar 76 or the projections, in which case Elemen¬ te of the holder must be exchanged 70 when circumference, ^_ 2c ^"fe7ϊΦr_ nlnesser or length should change the printing cylinder 72nd of the circumference and the pin 102 remains of the printing cylinder 72 changing with them length constant, then only the connecting tube 80 needs to be replaced, ^• without changes in the connected via the pins 86 connecting plates 90, off of these outgoing centering elements 92 or the tensioning lever 94 is required. If, on the other hand, the diameter of the cylinder pin 102 is changed without the scope and length of the pressure cylinder 72 being varied, only the centering plates 92 need to be replaced. Otherwise, the other elements can be retained in order to ensure a positionally accurate alignment of the holder 70 with respect to the longitudinal axis 74 of the printing cylinder 72. If only the circumference of the cylinder is changed and the length of the pressure cylinder is kept constant, an exchange of both the centering elements and the clamping levers is necessary in order to enable the holder 70 to be aligned in the correct position.

For this purpose, the holder according to the invention can be supplied with an assortment of centering elements, tension levers or holding tubes adapted to different cylinder dimensions, in order to be able to use the holder according to the invention in connection with different cylinder types without any problems.

Of course, the centering elements 92 can also be vertically displaceably embedded in the connecting plates 90, in order to enable adaptation to different cylinder circumferences and / or pin diameters. In these cases, the clamping levers then only have to be replaced if necessary.

If the simple alignment of clichés to be applied to printing cylinders 14, 72 by means of the holders 10, 38, 70 has been described in the exemplary embodiments, projections in the form of, for example, pins, which are also provided with, can alternatively be arranged detachably on the surface of the printing cylinder Recesses existing on pressure plates interact. As soon as the printing plate is glued to the surface of the printing cylinder, the pins can be removed. As a result, there are the same advantages with regard to the alignment as those described in connection with the brackets 10, 38, 70, even if this means that damage to the cylinder surface must be accepted.

OMPI / IPO

Claims

Claims:

1. Holder for printing plates to be brought onto a printing cylinder of a flexographic printing machine, characterized in that - the holder (10, 38, 70) comprises a rail (12, 40,. 76) which can be releasably arranged on the cylinder (14, 72), the projections (16, 42, 78) or recesses which interact with recesses or projections present in the pressure plates.

2. Holder according to claim 1, d a d u r c h g e k e n n z e i c h n e t that the aligned on the longitudinal axis of the cylinder holder (10, 38, 70) on the shaft (18, 102) of the cylinder (14, .72). is supported and / or at least partially surrounds it.

3. Holder according to claim 1, characterized in that the holder (10, 38, 70) U-shaped and by means of ,, on outer legs (20, 22, 46, 48, 90) existing fastening elements (24, 64, 92, 94) can be fixed in position on the cylinder (14, 72). 4. Holder according to claim 2 and / or claim 3, characterized in that the holder (38, 70) via centering elements (46, 48, 92 ⁾ on the shaft (18, 102) can be supported.

5- Holder according to claim 4, characterized in that the shaft (102) can be grasped on both sides by a clamping lever (94 ⁾ , via which a force in the direction of the respective centering element (92) can be generated.

6. Holder according to claim 4, characterized in that the centering element (92) has an approximately V-shaped recess (100) _. . which interacts with the shaft (102).

7.- Bracket according to claim 5, d a d u r c h g e k e n n z e i c h n e t that the clamping lever (94) for grasping the shaft (102) one

Counteracting spring force is preferably pivotable about an axis (112) by means of a tensioning screw (98).

8. Holder according to claim 1, d a d u r c h g e k e n n z e i c h n e t that along the end faces (44) of the cylinder (14) extending portions of the bracket movable jaws comprising the shaft (18).

9. Holder according to claim 8, d a d u r c h g e k e n n z e i c h n e t that over the the shaft (18) surrounding jaws (46, 48) one

Self-centering is bar.

OMPI 10. Holder according to claim 8 or claim 9, characterized in that the mutually facing regions of the jaws (46, 48) each have a preferably V-shaped recess (52, 54) to which the shaft (18) abuts in sections.

11. Holder according to claim 10, d a d u r c h g e k e n n z e i c h n e t that the recesses (52, 54) put together essentially form a square shape.

12. Holder according to claim 8, so that the jaws (46, 48) can be moved towards one another by spring force and can preferably be locked by means of a locking element (64).

13 «Bracket according to claim 1, d a d u r c h g e k e n n z e i c h n e t that the rail is detachably arranged on the bracket and parallel to the cylinder longitudinal axis.

14- Holder according to claim 1, so that the rail (12, 40) has orientation slots running in its longitudinal direction, which are on the surface of the impression cylinder

_.

(36) existing markings are aligned.

15. Holder for printing plates of a flexographic printing machine to be applied, characterized in that the holder consists of releasably arranged projections on the printing cylinder surface (36), which interact with recesses present in the printing plates. Thiocyanate, 16 mount on printing cylinders of a flexographic printing-making printing plates, characterized in that the holder consists of mono- transmitted recesses is to Druckzyli ^'ndero.berf laugh (36) engage in the existing on the pressure plates projections.

17. Holder according to claim 1 or claim 15, so that the projections (16) are pins.

18. Holder according to claim 4, d a d u r c h g e k e n n z e i c h n e t,

_. that the centering elements (92) are arranged displaceably perpendicular to the cylinder axis (74).

19. Holder according to claim 6, so that the recesses (100) of the centering elements (92) are displaceable with respect to the rail (78).

O PI