EP0686504B1 - Device for fastening and tensioning printing plates with Z-formed ends - Google Patents

Description

The invention relates to a device for fastening and clamping of printing plates with "Z" -shaped edges Ends according to the preamble of claim 1.

Fixing and tensioning devices of pressure plates with folded ends for Rotogravure printing machines are generally known.

EP 01 24 008 A2 describes a forme cylinder with a device for clamping flexible Pressure plates with clamping devices for folded ends a printing plate. These clamping devices are in a pit arranged and with a triangular segment body formed a hanging edge, the outer surface in tensioned state of the plate covers the pit gap and corresponds to the contour of the forme cylinder.

There is no guarantee that the plate also in the area of the hanging edge the cylinder periphery rests. Even the smallest Form deviations of the fold of the plate for Hooking edge of the cylinder can, especially at metallic gravure plates that are particularly stiff not be balanced.

From DE-PS 11 21 073 is a pressure plate lock known, with the "Z" -shaped printing plates attached and tensioned. Here press to Clamp the jaws on the bent legs of the Pressure plate, being on the cylinder periphery between a cavity in the pressure plate and the clamping jaws arises.

Both devices lead to an impermissible Enlargement of the area in which the shape deviations Plate can appear from the cylinder contour, d. H. the plate lies hollow on the gravure cylinder.

Especially in gravure printing processes become rigid Metal printing plates used in which the Shape deviations occur particularly strongly.

These shape deviations cause an uneven Print run of the squeegee, causing disruption of the paint application (e.g. ink spray) during gravure printing.

In order to guide the doctor blade as smoothly as possible To achieve this, opportunities were created to normally parallel to the cylinder axis Cross edges of squeegee blade and pit gap (e.g. squeegee inclination). This entanglement are Limits set by the fact that with strong Interlocking the contact pressure of the squeegee to the plate impermissibly strong in the axial direction of the cylinder changes (also due to uneven support of the Wear of the squeegee is too high).

The invention has for its object a Device for fastening and tensioning printing plates, especially gravure plates, with a "Z" shape to create bent ends and thereby the shape of the Pressure plate in the area of the pressure plate ends exactly the Adapt cylinder contour.

This task is characterized by the characteristics of the characterizing part of claim 1 solved.

The advantages that can be achieved with the invention exist in particular in that with the invention Device shape deviations of a printing plate from one Forme cylinder contour in the area of the hanging edges, d. H. hollow of the pressure plate ends can be minimized. Paint spraying is achieved by the device according to the invention in the gravure printing process, which is caused by uneven installation of the doctor blade on the rotogravure plate is avoided. In addition, the wear on both sealant closes the pit gap, as clearly on the squeegee decreased. When opening the hanging edges, the Sealant removed automatically.

The device according to the invention is in the drawing shown and is described in more detail below.

Fig. 1

einen Radialschnitt der erfindungsgemäßen Vorrichtung mit geöffneten Spannelementen;

Fig. 2

einen Axialschnitt II-II entsprechend Fig. 1;

Fig. 3

einen Radialschnitt der erfindungsgemäßen Vorrichtung mit teilgeschlossenen Spannelementen;

Fig. 4

einen Radialschnitt der erfindungsgemäßen Vorrichtung mit halbgeschlossenen Spannelementen;

Fig. 5

einen Radialschnitt der erfindungsgemäßen Vorrichtung mit geschlossenen Spannelementen.

Show it

Fig. 1

a radial section of the device according to the invention with open clamping elements;

Fig. 2

an axial section II-II corresponding to FIG. 1;

Fig. 3

a radial section of the device according to the invention with partially closed clamping elements;

Fig. 4

a radial section of the device according to the invention with half-closed clamping elements;

Fig. 5

a radial section of the device according to the invention with closed clamping elements.

A gravure form cylinder shown in Fig. 1 1 has a left 2 and right 3 swiveling, acute-angled hook-in edge, their respective outer Surface 5 on a curvature of a forme cylinder contour is adapted and thus in the exciting state Forme cylinder contour without paragraph, continuously continued. These pivoting hanging edges 2, 3 run parallel to the cylinder axis and limit one Cylinder pit 7 on the side. In the hanging edges 2, 3 is each have a folded end 4, 6 of a gravure printing plate 8 hung. An opening angle alpha of the ends 4, 6 can be 45 °, but preferably less than 45 °, e.g. B. 35 °, be. In the interior of a cylinder pit 7 extending legs 9, 11 of the folded ends 4, 6 each follow a rounding 12, 13, in which is a non-folded part of the rotogravure plate 8 passes. Sit on the first legs 9, 11 each leg 14, 16 continued with the first Legs 9, 11 each with a second bevel 17, 18 form an opening angle beta. This opening angle Beta can also be 45 °, but preferably smaller 45 °, e.g. B. 35 °. This second bend 17, 18 is on the opposite end 6, 4 of the Gravure plate 8 directed. With a flat Gravure plate 8 have the two ends 4, 6 and two bevels 17, 18 approximately the shape of a "Z".

On a bottom 19 of the cylinder pit 7, the right and is delimited on the left by the hooking edges 2, 3, is a bar 21 approximately the length of a cylinder pit arranged.

Through a right and left side surface 22, 23 and a base area 24 becomes approximately trapezoidal Cross section of the bar 21 formed. The side faces 22, 23 close with the base 24 of the bar 21 each an angle gamma that is about 0.5 ° to 5 ° is smaller than the opening angle beta that the Legs 9, 11 with the legs 14, 16 of the folded Form ends 4, 6 of gravure plate 8. Through the Side surfaces 22, 23 and the base surface 24 arise Corner edges 26, 27. A distance a1 between the corner edges 26, 27 is equal to or slightly longer than a distance a2 the folds 17, 18 of the attached gravure plate 8 with the hanging edges 2, 3. The base area 24 runs parallel to the bottom 19 of the cylinder pit 7 and in the closed state of the hanging edges 2, 3 the legs 14, 16 of the gravure printing plate 8 parallel to the base 24.

At both ends 28, 29 of this strip 21 are cuboid guide pieces 31, 32 attached in Grooves 33, 34 run. The groove 33 or 34 in the base 19th the cylinder pit 7 is wider than the cuboid Guide piece 31 or 32, so that the bar 21 in Direction of the hooking edges 2, 3, d. H. in the direction the fold 17, 18 is movable. Along the groove 33, 34 allow the guide pieces 31, 32 a radial Movement of the bar 21 (Fig. 2).

This radial movement is caused by, for example, one cylinder-fixed bolt 36, the in a slot 37 with Length of the path of the bar 21 in the radial direction intervenes, limits. Between the guide pieces 31, 32 are under the bar compression springs 38, which are in the reason 19 of the cylinder pit 7 and on the base 24 of the Support bar 21, arranged (Fig. 1 and Fig. 2).

The intaglio printing process is running as follows:

In order to clamp the gravure plate 8, the Hook-in edges 2, 3 with the hooked, folded edges Ends 4, 6 of the intaglio plate 8 in the direction of Cylinder pit 7 pivoted. Here the legs 9, 11 of the folded ends 4, 6 of the gravure printing plate 8 against the side surfaces 22, 23 of the trapezoidal bar 21 pressed, causing the bar 21 against the compression springs 38 moves in the direction of the bottom 19 of the cylinder pit 7 becomes. The legs 14, 16 of the gravure printing plate 8 are during this movement under the base 24 of the trapezoidal bar 21 guided (Fig. 3 and Fig. 4).

Shortly before the swivel movement of the hanging edges is completed 2, 3 - d. H. before reaching the end position of the Hook-in edges 2, 3 - include the folds 17, 18 the corner edges 26, 27 of the trapezoidal ones near the pit Ledge 21 are now by further swiveling the Hook-in edges 2, 3 with the hooked, folded edges Ends 4, 6 of the intaglio plate 8 these ends 4, 6 exactly drawn on the hooking edges 2, 3. This fits the gravure printing plate 8 also in the area of the hanging edges 2, 3 exactly on the cylinder contour (Fig. 5).

Parts list

1

Gravure form cylinder

2nd

Hook-in edge, left (swiveling)

3rd

Hooking edge, right (swiveling)

4th

End, beveled

5

Surface, outer (2, 3)

6

End, beveled

7

Cylinder pit

8th

Gravure plate

9

leg

10th

-

11

leg

12th

Rounding

13

Rounding

14

leg

15

-

16

leg

17th

Folding

18th

Folding

19th

Reason (7)

20th

-

21

Strip, trapezoidal

22

Right side (21)

23

Left side (21)

24th

Footprint (21)

25th

-

26

Corner edge, right (21)

27

Corner edge, left (21)

28

End, first (21)

29

End, second (21)

30th

-

31

Guide piece, first (21)

32

Guide piece, second (21)

33

Groove, first (19)

34

Groove, second (19)

35

-

36

bolt

37

Slot (28, 29)

38

Compression spring

a1

Distance between the corner edges (26, 27) of the bar (21)

a2

Bending distance (17, 18)

alpha

Opening angle (4, 6)

beta

Opening angle (17, 18)

gamma

Angle (21)

Claims (4)

1. Device for fastening and tensioning gravure printing plates (8) having ends bent over in a "Z" shape (4;6) on a gravure-printing forme cylinder (1), characterized in that pivotable hook-in edges (2;3), which are adapted to the ends (4;6) bent over in a "Z" shape and whose respective outer faces (5) have a curvature of the cylinder contour, are arranged so that they run parallel to the axis of the gravure printing cylinder and bound a cylinder gap (7), in that the outer faces (5) of the pivotable hook-in edges (2;3), in the tensioning end position, are provided such that they continue the cylinder contour without an offset, in that a bar (21), which has a trapezoidal cross-section, is sprung in the radial direction of the gravure-printing forme cylinder (1) and is moveable in the direction of the two hook-in edges (2;3), is arranged along the cylinder gap (7), and in that angular edges (26;27) of the bar (21), which are formed by side faces (22;23) and bottom face (24), are arranged so as to engage in bent-over edges (17;18) of the gravure printing plate (8).
2. Device according to Claim 1, characterized in that an angle (Gamma) of the bar (21), this angle being formed by the side face (22) or (23) and the bottom face (24), is smaller than an opening angle (Beta) of the bent-over edge (17) or (18) of the gravure printing plate (8), this angle being enclosed by the legs (9) and (14) and, respectively, (11) and (16).
3. Device according to Claim 1, characterized in that a spacing (a1) between the angular edges (26,27) of the bar (21) is equal to or slightly longer than the spacing (a2) between the bent-over edges (17,18) of the hooked-in gravure printing plate (8) when the hook-in edges (2,3) are closed.
4. Device according to Claim 1, characterized in that the bar (21) is fitted with guide pieces (31,32), with which the bar (21) is mounted in grooves (33,34) in the bottom (19) of the cylinder gap (7) so that the said bar can move radially in relation to the gravure-printing forme cylinder (1) and in the direction of the bent-over edges (17,18).

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