DE8813594U1 - Copier for exposing printing plates - Google Patents

Description

Applicant: Krause-Biagosch GmbH

Paul-Schwarze-Strasse 5
4800 Bielefeld 14

Description: Copier for exposure of

Printing plates

The innovation relates to a copier for exposing printing plates of the type specified in the generic term of claim 1.

For a flawless copying process with such a copier, it is important to position the printing template, which is usually a film, in a predetermined alignment on the printing plate, which is arranged in a predetermined position via the registration device on the top of the machine table. In the known copiers of the type mentioned at the beginning, the respective template already takes up a corresponding position on the feed cassette, from which it is only transported by essentially plane-parallel offset over the copy frame to the printing plate resting on the machine table. The appropriate alignment of the printing templates on the template cassette is ensured by the registration device there. The copy frame serves as the means of transport for the printing templates, under which the template cassette moves in a raised position. After that, it lowers

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The copy frame is placed on the printing template on top of the template cassette and picks it up using the holding device on the underside, which is usually a suction device. After the copy frame is raised, the template cassette is moved out of the travel area of the copy frame, after which the copy frame is lowered down to the printing plate resting on the machine table in order to press the printing template firmly onto the top of the printing plate.

In the known copiers, the necessary positioning accuracy of the print template on the printing plate is achieved by particularly rigid guides, both for the template cassette that can be inserted under the raised copy frame and for the height-adjustable copy frame. A correspondingly high level of effort is required for these two guide devices in order to ensure the exact positioning of the print template on the printing plate.

The innovation is therefore based on the task of enabling a very precise, positionally accurate transfer of the printing template to the copying frame and a correspondingly very precise placement of the printing template on the printing plate resting on the machine table using simple structural means in a copying machine of the generic type.

This object is achieved in a copier of the generic type according to the innovation by the characterizing features of claim 1

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The particular advantage of the innovation is that the associated guide device for the floating support of the copy frame can be designed with a large amount of play, which places only minimal demands on the accuracy of the individual components. Both when placing it on the template cassette and when lowering it onto the machine table, the large amount of play in the guide device for the copy frame allows sufficient flexibility in the copy frame plane so that it can be precisely adjusted to the template cassette on the one hand and to the machine table on the other.

In the same way as with the copy frame, the guide device for the original cassette can be simplified and equipped with a large amount of play. It is crucial that in the retracted transfer position the original cassette and the copy frame can align exactly with each other.

Further advantageous design features of the innovation emerge from the subclaims.

The innovation is explained in more detail below using the drawing of an example. Show:

Fig. 1 is a schematic side view of a copier for exposing printing plates,

Fig. 2 is a schematic perspective view of the feed cassette, the copy frame and the table top of the copy machine according to Fig. 1 and

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Details of the index system and the suspension of the copy frame of the copier according to figures 1 and 2,

In detail, one can see a table 1 of the copier in Fig. 1, above which an exposure head 2 is arranged, in which a lamp 3 is located. Furthermore, one can also see a diffusion foil 4 on the underside of the exposure head 2. The table 1 has a printing plate 5 on its top that is to be exposed. This is used to copy the image of a printing template 6 onto the photoactive printing plate 5, which must be placed from above in the correct position on the printing plate 5 on the machine table 1. The means of transport for this is a copying frame 7, which has a central light passage opening in order to be able to expose the printing plate 5 through it and the template 6. The copy frame 7 holds the respective printing template 6 on its underside; for this purpose, it has a suitable holding device which uses negative air pressure to suck the printing template 6 onto the underside of the copy frame 7. The copy frame 7 can be lowered from the upper end position shown in Fig. 1 down to the printing plate 5 resting on the table 1; it can be adjusted in height accordingly on a guide device not shown in detail in Fig. 1.

The printing templates 6 are fed to the copying frame 7 by means of a template cassette 8, which can be moved over the table 1 in the raised end position of the copying frame 7 and has a stack 9 of printing templates 6 on the top in a positionally correct position for transfer to the copying frame 7. A registration device on the top is used for this purpose.

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on the original cassette 8, which usually consists of the alignment pins 15 visible in Fig. 2. During the transfer process, the copy frame 7 is lowered onto the stack 9 on the retracted original cassette 8, after which the upper original 6 is removed by the suction device mentioned and then the copy frame 7 is raised again. The original cassette 8 then moves back out of the travel range of the copy frame 7 and the exposure process takes place.

The copying frame 7 then places the no longer required print template 6 on a storage cassette 10, which can also be inserted above the table 1 under the raised copying frame 7.

At the same time, a new printing plate 5 is conveyed to the table 1 via the storage cassette 10 and at the same time the storage cassette 10 pushes the exposed printing plate 5 from the table 1 into a storage station 13. The printing plates 5 are kept ready as a stack 11 on a carriage 12, which is positioned according to the outer end position of the storage cassette 10.

The precise alignment of the copy frame 7 to the feed cassette 8 on the one hand and of the copy frame 7 to the table 1 on the other hand is carried out by an index system, the details of which can be seen in Fig. 2. This index system makes it possible to implement the guide device 14 required for the movement of the original cassette 8 and the guide device 16 required for the vertical movement of the copy frame 7 using simple structural means which allow a relatively large amount of play, whereby the copy frame 7 can be

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its guide device 16 and the original cassette 8 are mounted floating on its guide device 14.

In detail, the index system consists of index members 17 that protrude from the underside of the copy frame 7. Accordingly, both the original cassette 8 and the table 1 have index counter members 18 and 19 that engage with the index members 17 of the copy frame 7 as soon as the copy frame 7 is lowered either onto the original cassette 3 or onto the table 1. This automatically centers the copy frame 7 in relation to the system cassette 8 or the table 1. The index members 17 and index counter members 18 and 19 are equipped with corresponding run-in slopes and are also designed in such a way that tilting or jamming is impossible.

The right index member 17 on the copy frame 7 in Fig. 2 interacts with the respective index counter-member 16 of the original cassette 8 or the table 1 in such a way that a polar alignment is established between the parts to be harmonized. The corresponding angular alignment is provided by the index member 17 on the opposite, left side of the copy frame 7, which interacts with index counter-members 19 of the original cassette 8 and the table 1, each of which consists of a long hole or slot.

Fig. 3 shows in addition that the index members 17 of the copy frame 7 are PaO pins 23 with a spherically thickened head 24. This head 24 fits into a counter hole 25/ which is circular as the index counter member 18.

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or represents an elongated hole as an index counter-member 19. On the insertion side, the hole 25 has a funnel-like widening 26 to enable automatic insertion of the spherically thickened head 24 of the dowel pin 23. The hole 25 is expediently designed as a through hole and consists of a bore in a bushing 27 let into the template cassette 8 and the table 1.

In the illustration to the right of Fig. 3, one can see a guide rod 20 of the guide device 16 for the copy frame V, which engages with a molded-on guide head 21 in a guide slot 22, to which, as indicated by the arrows below, there is play on all sides in the direction of the copy frame plane.

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Claims (5)

1. Copying machine for exposing printing plates with a table equipped with upper registration devices for holding one of the printing plates, with an exposure head arranged above it and a copying frame which can be moved in height above the table on a guide device with a light passage opening, on the underside of which a holding device for a translucent printing template is arranged, and also with a template cassette which can be moved on a guide device up to below the raised copying frame above the table and which has a registration device for the printing templates which are to be held on it in precise position for transfer to the underside of the copying frame, characterized, that the copy frame (7) is mounted in a floating manner on its guide device (16) and has index members (17) which interact in a self-introducing manner with index counter-members (18, 19) which are arranged on the one hand on the original cassette (8) and on the other hand on the table (1). 2. Copying machine according to claim 1, characterized in that the feed cassette (8) is floatingly mounted on its guide device (14). it 4» *·« &bgr;&Igr; III - 2 - 3494a 3. A copier according to claim 1 or 2,
characterized, that the copy frame (7), the original cassette (8) and the table (1) each have two index members (17) or two index counter members (18, 19), of which one is designed for polar centering and the other for angular alignment relative to the polar point. 4. A copier according to claim 3, characterized in that the index members and counter-members (17; 18) for the polar centering consist of a centering pin (23) with a radially projecting, spherical head (24) and a counter-hole (25) with an inner diameter corresponding to the head (24), the counter-hole (25) having a funnel-like widening (26) on its insertion side. 5. A copier according to claim 3 or 4, characterized in that the index members and counter-members (17; 19) for the angular alignment consist of a centering pin (23) with a radially projecting, spherical head (24) and of an elongated hole or slot, the width of which corresponds to the diameter of the head (24) and which has a funnel-like recess (26) on its insertion side.