EP0221322A2 - Process for applying a protective covering to a printing cylinder, and device for carrying out the process - Google Patents

Abstract

A flexible plate (1, 36, 65) is used for coating or covering a printing group cylinder (30, 44, 50, 63), which is provided with a double-sided adhesive film (2) in accordance with the cylinder circumference to be covered. The trailing end (4, 38, 68) of the plate (1, 36, 65) to be glued is provided with a liquid adhesive. The leading end is first fixed to a wall of the cylinder pit (31, 47, 64) by means of fixing leads (41, 57, 58, 67), after which the plate is glued onto the jacket under rolling and finally the rear end is used using the liquid or pressure-sensitive adhesive is glued to the other cylinder wall.

Description

The invention relates to a method for applying a protective coating to a printing couple cylinder according to the preamble of claim 1 and devices for carrying out the method.

From DE-OS 3 401 350 it is known to provide through-cylinder with a ceramic coating which covers both the cylinder jacket and partially the pit walls of the cylinder pit. It is also known, for example from DE-AS 22 49 195, to glue thin plates serving as printing form carriers to a printing couple cylinder, a frame being used on a base plate into which the plate is glued. However, these plates only partially cover the outer surface of the cylinders, so that the plates do not completely protect them against corrosion.

• Fig.1 die Belegung einer flexiblen Platte mit einer Klebstoffolie,
• Fig.2 die erfindungsgemäß beschichtete, flexible Platte,
• Fig.3 bis 6 eine Vorrichtung zum kantengenauen Abbiegen der Platte gemäß Fig.2,
• Fig.7 die in Fig.2 dargestellte, an den Enden abgewinkelte, flexible Platte,
• Fig.8 und 9 die erfindungsgemäße Belegung eines Druckwerkzylinders mit einer Platte gemäß Fig.2,
• Fig.10 und 11 die erfindungsgemäße Belegung eines Druckwerkzylinders mit einer Platte gemäß Fig.7 und
• Fig.12 die erfindungsgemäße Belegung eines Plattenzylinders mit einem einzigen schmalen Zylinderschlitz.

The object of the invention is to provide a method for applying a protective coating to a printing cylinder, which covers the cylinder jacket and at least partially the pit walls, in the form of a flexible plate which is provided with a homogeneous adhesive layer of the same thickness and over the entire cylinder a uniform adhesive force is applied without bubbles. This object is achieved by the features of the characterizing part. Further developments of the invention result from the subclaims in connection with the description and the drawings. These show schematically:

• 1 shows the covering of a flexible plate with an adhesive film,
• 2 the flexible plate coated according to the invention,
• 3 to 6 a device for bending the plate with the exact edge according to FIG. 2,
• 7 the flexible plate shown in FIG. 2, angled at the ends,
• 8 and 9 the assignment according to the invention of a printing couple cylinder with a plate according to FIG. 2,
• 10 and 11 the assignment of a printing unit cylinder according to the invention with a plate according to Fig. 7 and
• 12 shows the assignment of a plate cylinder according to the invention with a single narrow cylinder slot.

According to FIG. 1, a flexible plate (1) that is corrosion-resistant, such as, for example, stainless steel, is covered with a film (2) that has a homogeneous adhesive layer on both sides. The adhesive on the film (2) is intended to bring about an immediate bond as soon as it comes into contact with a counter layer or surface, it not being absolutely essential that the maximum adhesive effect be achieved immediately. Such adhesives are referred to as so-called "single-sided contact adhesives". The adhesive layer on the film (2) must be extremely homogeneous and have a uniform thickness. The film (2) or the adhesive layers located on this on both sides are covered by a protective layer S, for example also made of a thin film material, so that the adhesive film can be stored on a winding roll. In the manner according to the invention, the plate (1) shown in FIG. 2 is first to be coated with a film (2), the plate ends (3, 4) to be inserted into the cylinder pits being glued in different ways. While the plate end (3) and the remaining plate (1) covering the cylinder jacket are covered with the film (2), the other plate end (4) is not covered with the film (2). A film-free area or space (5) is preferably provided on the plate (1), which, as will be explained in more detail later, comes to lie above the leading edge of the pit. According to FIG. 1, the film (2) is pulled off a supply roll (6) and rolled onto the flexible plate (1) without bubbles and with even pressure using an elastic pressure roller (7). Here is Take special care so that the film (2) comes to lie on the plate (1) without bubbles and with a uniform adhesive force. To create the area (5), a narrow strip can subsequently be cut out if the plate (1) is covered with the film (2), with the exception of the plate end (4). In the illustration according to FIG. 2, there is therefore only a protective film S on the upper side of the film (2) which covers the upper adhesive layer.

FIGS. 3 to 6 show a bending device with which the plate (1) shown in FIG. 2 can be angled at the two ends (3, 4) in order to later use the ends (3, 4) in accordance with the invention To fix pit walls of printing unit cylinders, ie to glue. Corresponding to the circumference of the casing, the plate (1) is bent to the exact edge using the bending device shown in FIGS. 3 to 6. This comprises side walls (9, 10), between which a cylinder (11) is mounted, which has a relatively wide pit (12). The width and diameter of the cylinder (11) serving as the bending shape are therefore precisely matched to the size of the printing unit cylinder to be covered with the plate (1).

In the pit (12) there is a support bar (13), parallel and in the vicinity of the pit wall (14). The distance of the support bar (13) to the other pit wall (15) is preferably somewhat larger than the distance between the support bar (13) and the pit wall (14). As a result, the insert strip (16) shown in FIG. 4, which has holes (17), can be screwed into threaded holes in the bottom of the pit (12) using screws, not shown. Between the side of the insert bar (16) and the pit wall (15) facing the pit wall (15) there is a pulling and fixing bar (22) according to FIG. 6 and a fixing bar (19) between the support bar (13) and the pit wall (14) ) can be used according to Fig. 5. The fixing bar (19) and the pulling and fixing bar (22) have through holes (20 and 23 respectively) and eccentric holes (21 and 24). In the latter, eccentrics, not shown, are used, for example, with an Allen key, which can be rotated out of the side faces of the strips (19, 22) during rotation.

For the edge-precise bending of the plate according to FIG. 2, the plate end (3) is first inserted into the pit (12) so that it comes into contact with the pit wall (14). The fixing bar (19) is then inserted between the pit wall (14) and the support bar (13), this being fixed to the pit floor by means of screws and by means of rotatable eccentrics in the eccentric holes (21) against the pit wall (14) or against that on the pit wall (14) abutting end (3) of the plate (1) is pressed so that the plate end (3) is exactly fixed. By manual or motorized rotation of the cylinder (11), an elastic pinch roller (25), which is also rotatably mounted between the side walls (10, 11), is used to precisely bend the end defined in the manner described above, here (3) reached the plate (1) and, when the cylinder (11) is turned further, the plate (5) is rolled onto the jacket of the cylinder (11) until the other plate end, here (4), is bent over by the pressure roller (25) and into the pit (12) is pushed into it. After using the pressure roller (25) the bend is exactly finished, the plate end (4), for example by hand, is placed against the pit wall (15) and then between the insert bar (16), which is by means of the holes (17) and the threaded holes (18) have already been fastened in the pit (12), and the pit wall (15) has inserted the pulling and fixing strip (22). The end (4) is now pressed completely against the pit wall (25) by means of rotatable eccentrics, not shown, in the eccentric holes (24), after which the pulling and pulling screws are inserted through the holes (23) into the threaded holes (18) Fixing strip (22) is pressed downwards against the pit wall (15) or the plate end (4) resting thereon, ie towards the pit floor. This completes the folding process, with the plate end being pulled down along the pit wall (15). Preferably, at least the side of the pulling and fixing strip (22) abutting the plate end (4) should be roughened, for example corrugated, so that the pulling action which acts on the end (4) of the plate is increased. A similar corrugation or roughening can also be carried out on the corresponding side of the fixing strip (19).

Another advantageous embodiment of the bending device according to FIG. 3 is that the cylinder (11) has cutting grooves (26, 27) on both sides, into which disk-shaped knives (28, 29) engage. When the bending process is complete, the plate (1) on the cylinder (11) is cut to the required width precisely and without distortion by appropriate adjustment of the knives (28, 29).

The plate (2) bent on the device according to FIG. 3 can now be removed from the cylinder (11) by loosening the parts (16, 19, 22) and brought back into the position shown in FIG. Advantageously, the pre-bent plate (1) can be subsequently applied to a cylinder in a printing press, which will be described in more detail below.

First of all, however, the application of a plate (36) according to the invention, which has the structure according to FIG. 2, is described with reference to FIGS. 8 and 9, wherein no pre-bending or pre-bending is required. The method described in connection with FIGS. 8 and 9 is preferably used in the production of a printing group cylinder, while the method shown in FIG. 10 is suitable for applying the plate (1) in the installed state of the printing group cylinders. The cylinder (30) shown in FIGS. 8 and 9, for example a blanket cylinder, has a pit (31) with channels (32, 33), on the walls (34, 35) of which the plate ends 37, 38) of a flexible plate ( 36), which is coated like the plate (1) according to FIG. 2. The plate (36) is rolled onto the cylinder (30) using a pressure roller (39) which is rotatably attached to the jacket of the cylinder (30). The cylinder (30) also rotates in the direction of the arrow in printing operation.

First, with removal of the lower protective film S, the end (37) of the plate (36) covered with the film (2) is placed against the pit wall (34), after which a fixing strip (40) is inserted into the pit channel (32) and at the bottom of the Pit channel (32) is screwed. The fixing bar (40) is preferably constructed similarly like the fixing bar (19) according to Fig. 5. Then, while rotating the cylinder (30), the plate (36) is glued onto the jacket of the cylinder (30) by the pressure roller (39), the corresponding protective film S having to be removed successively. This process continues until, according to the position shown in FIG. 8, the pressure roller (39) folds the rear end (38) of the plate (36) at the trailing edge of the pit and at least partially the rear end (38) into the pit (31 ) pushes in. In the rear cladding area, for example at (42), the protective film S is not immediately removed from the adhesive layer, since after the end (38) has been bent, the roller (39) or the cylinder on the trailing edge (52) again in the opposite direction is rotated, after which, as indicated by the broken line in FIG. 8, the end (38) is inserted into the pit channel (33). Now the plate (42) is finally rolled onto the jacket of the cylinder (30) to the trailing edge of the pit (52) with the help of the pressure roller (39), removing the protective film S, ie glued on. The plate (36) is bent exactly around the trailing edge of the pit (52). In this position, a pulling and fixing strip (41) is inserted, which is constructed in accordance with the pulling and fixing strip (22) according to FIG. Before the insertion process, however, either the lower side of the end (38) of the plate (36) or the pit wall (35) was coated with a liquid adhesive or a pressure-sensitive adhesive which, when the end (38) was in contact with the pit wall (35) initially allows a displacement of the end (38) on the pit wall (35). It is thereby achieved in the manner according to the invention that when the pulling and fixing strip (41) is pulled in or screwed in, the plate (36) or the end (38) lies precisely and extends along the trailing edge of the pit (52) and the pit wall (35 ) he follows. The strips (40, 41) now remain in the pit channels (32, 33) until the adhesives used have approximately reached their final strength. As can be seen in FIG. 8, the plate (36) was also guided exactly around the leading pit edge (51), it being extremely advantageous that the area above the leading pit edge (51), in the direction of rotation of the printing unit cylinder, was free of the adhesive film is (see area 5). As a result, no material accumulation on the Pit edge (51) occur during the fold, which would otherwise have an adverse effect on the life of the coating and a fold would not be possible exactly.

10 schematically shows rubber cylinders (43, 44) with associated plate cylinders (45, 46), as are used in conventional web-fed rotary printing presses. Here, the application of a flexible plate with a built-in printing unit cylinder, here a blanket cylinder (44), is to be demonstrated retrospectively or if the protective covering needs to be replaced. For this purpose, the plate (1) angled according to FIG. 7 is inserted into the pit with the end (3) covered with film (2) and fixed in the manner already described in connection with FIGS. 8 and 3 by means of a fixing piece or fixing strip. Then the two rubber cylinders are slowly rotated and a deformable, thus elastic pressure roller (48) is placed between the rubber blanket cylinders (43, 44). As a result, the pressure roller (48) is pulled between the blanket cylinders (43) and (44) in the deforming area (49), so that when the cylinders (43, 44) are rotated, the plate (1) is pressed onto the jacket of the cylinder with a large and uniform pressure force (44) if the lower protective film S is removed beforehand. The pressure roller only rotates at low speed because it is separated by the rubber cylinder (43). When the blanket cylinder (44) with the pit (47) reaches the position shown in dashed lines, the end (4) not coated with film can also be inserted into the pit. The means shown in FIG. 11 can be used for this, which can also be used in connection with the application method according to FIGS. 8 and 9.

The cylinder (50) shown in FIG. 11, for example a blanket cylinder, was covered with a plate (1) according to FIG. 2 or 7. The pit edge (51) leading in the direction of rotation of the printing unit cylinder (50) was also covered with a plate (1) which has an area (5). Preferably, no adhesive is used above the trailing edge of the pit (52).

The ends (3, 4) which were fastened to the pit walls (53, 54) in the manner already described, for which purpose the fixing strips (57, 58) which could be fastened by means of threaded holes (55, 56) were used, corresponding to the strips (19, 22 , Fig. 5, 5). As a result, the plate ends (59, 60) are pressed against the pit walls (53, 54), a pulling action being exerted on the plate end (60) in the direction of the pit floor in the manner described. The pit channels are provided with the threaded holes (55, 56) which are engaged by screws, not specified, which are guided through holes (61, 62) in the strips (57, 58). After appropriate drying of the adhesives used, the parts (57, 58) are removed again, after which the process is completed.

A further advantageous variant of the invention results from FIG. 12, in which a plate cylinder (63) is shown, in which the ends of the pressure plate or mold are inserted together in a single narrow cylinder slot (64) which extends in the axial direction. Such cylinders can also be covered with an elastic plate, here an elastic plate (65) corresponding to the structure according to FIG. The end (66) of the plate (65) leading in the direction of rotation of the cylinder (63) is fixed in the manner already described in connection with FIGS. 7 and 8 with the aid of an insert strip (67) on the one pit wall of the cylinder slot (64). The cylinder slot (64) advantageously has a recess (69) on the trailing edge of the pit (52). The length of the plate (65) to be glued is now dimensioned such that the trailing plate end (68), as indicated in FIG. 12, only projects as far beyond the trailing edge of the pit (52) as the cylinder slot is wide. By using an elastic pressure roller (70) on the jacket of the plate cylinder (63) corresponding to the pressure roller (39), after the plate (65) has been rolled onto the cylinder jacket, the trailing plate end (68) is now pressed into the recess (69), wherein the deformation of the pressure roller (70) shown in dashed lines in the region (71) can be observed. Of course, the area in the recess (69) was previously provided with a suitable adhesive or, if necessary, with this arrangement according to FIG. 12, only the very narrow end (68) protruding beyond the trailing edge of the pit can be glued with the film, which, however is somewhat less convenient than using a liquid adhesive or a pressure sensitive adhesive.

The inventive use of the newly constructed and manufactured flexible plate thus enables a safe, uniform and bubble-free application of a protective coating on printing unit cylinders which adhere with uniform force over the entire cylinder jacket and which, due to the homogeneity of the adhesive, ensure a favorable concentricity of the coated cylinder. The advantages that the present invention brings include in the fact that instead of the previously required complex coating of printing unit cylinders with chrome, nickel, ceramic or other corrosion-resistant layers can now be carried out more cheaply, a further advantage being that the subsequent application of the plate according to the invention in the installed state or the replacement of already applied plates is inexpensive to do.

Claims (10)

1. Method for applying a protective covering to a printing couple cylinder, which covers the cylinder jacket and, at least partially, the pit walls of the cylinder pit,
characterized,
that the protective covering consisting of a flexible plate (1, 36, 65) is covered on one side with a film (2) provided with contact adhesive on both sides, in such a way that seen in the direction of rotation of the printing unit cylinder (30, 44 50, 63), the leading plate end (3, 38, 69) protruding into the pit (31, 47, 64) and the plate (1, 36, 65) resting on the cylinder jacket are covered with the film (2), and the trailing end ( 4, 38, 68) over the trailing cylinder edge (52) and the trailing pit wall (35, 54, 69) with a liquid adhesive or a pressure sensitive adhesive. 2. The method according to claim 1, characterized in that the plate (1, 36, 65) in the region of the leading pit edge (51) has an area (5) which is film-free. 3. The method according to claim 1 or 2, characterized in that the plate (1) in the stretched state by an elastic pressure roller (7) with the film (2) under pressure and with removal of the lower protective layer (S) on the film (2 ) is occupied. 4. The method according to claim 3, characterized in that the sheet (2) covered plate (1) angled precisely in a bending device (Fig.3) bypassing a rotatable cylinder (11) at the end regions (3, 4) becomes. 5. The method according to claim 4, characterized in that on a printing unit cylinder (44) in a printing press (Fig.10) at the ends (3, 4) angled plate (1) with removal of upper protective layer (8) in the film (2) with the leading end (3) glued to the associated pit wall (35) and the glued end (3) is held by a fixing strip (40), after which by means of a pressure roller (48) under Rotation of the printing unit cylinder (44), the plate (1) with the exposed upper side of the film (2) is rolled onto the cylinder jacket, the rear end (4) with the pressure roller (48) turned on with the aid of a pulling and fixing strip (58) is glued to the trailing cylinder wall (54) and stretched towards the pit floor (Fig. 10, 11). 6. The method according to claim 5, characterized in that the elastic pressure roller (48) between two rotating during the cylinder assignment printing unit cylinder (43, 44, Fig.10) is pulled. 7. The method according to claim 1 or 2, characterized in that in the stretched state, the plate (1) with its film (2) covered end (3) is glued to a pit wall (34) and is held by a fixing strip (40) Then, with an elastic pressure roller (39), the plate (1) covered with the film (2) is rolled up with the end (37) bent onto the cylinder (30) until the rear end of the plate (38) of the plate (1) the pressure roller (39) on the trailing edge of the pit (52) is angled to the exact edge, in the area (42) in front of the trailing edge of the pit (52) the top protective layer of the film (2) is not peeled off first, after the rear plate end (38 ) the pressure roller (39) is moved back again, the upper protective layer (2) is now removed and the angled plate end (38) is inserted into the pit while rolling up the plate (36), the pressure roller (39) being the one with the adhesive Foil-covered plate (36) to the na Chollen pit edge (52) rolls, after which the rear plate end of the plate (36) is fixed by a liquid adhesive on the trailing pit wall (35) by a clamping and fixing bar (40) clamping the plate end (38) and pulling towards the pit floor. 8. The method according to claim 1 or 2, characterized in that the rear non-angled plate end (38) of the plate (35) to the width of the two plate ends (68, 69) receiving cylinder (34) is cut and by the pressure roller (70 ) is pressed into a recess (69) in the cylinder slot (64) while deforming the pressure roller (70) for the purpose of gluing (Fig. 12). 9. A device for producing a plate for the method according to claim 4, characterized in that the device (Fig.3) comprises a with a cylinder pit (12) provided rotatable cylinder (11) in which a support strip (13) is arranged and into which (12) a fixing bar (19) can be screwed, which can be pressed against the one pit wall (14) by eccentrics and that on the other side of the supporting bar (13) a pulling and fixing bar (22) can be screwed to the pit bottom, which can be pressed against the other pit wall (15) via eccentrics in guides (24) with support on the support bar (13) and can be pulled towards the pit bottom by screws in holes (23) in the pulling and fixing bar (22), so that the the plate end (13) lying against the cylinder wall (15) is pulled towards the pit wall and tensioned. 10. Printing unit cylinder, produced by a method according to one or more of claims 1 to 7.

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