DE2121502A1 - Method and device for preparing and checking a photographic master copy which is to be transferred to a sensitized printing cylinder - Google Patents

Description

Patent Attorneys Dlpl.-lnc ;. Π. "" I ' T TL sen.

DIpI-SnO. f.; /. ' - ·. ;: cHT

Dr.-lri- ;. Γ. Γ-J .: '- ■ C Z. Jr.
8 Munich 22, Sieinsdorfstrasse 4 £ _ _{l6 #} ^ p (^ _970n ) April 30, 1971

Roger, Jules , Justin BASSEREAU, Aulnay sous Bois (France)

Method and device for preparing and checking a photographic master copy, which is to be transferred to a sensitized printing cylinder

The invention relates to a method and a device for preparing and checking a photographic Copy templates to be transferred to a sensitized printing cylinder for heliography, offset printing etc.

Up to now, the testing of a heliography printing cylinder could only take place in the final stage of its manufacture, d. H. when the first attempts at printing are made; the errors that appear are very often such, that they cause the cylinder in question to be discarded; these errors are the ones that are in the Mainly show or affect by a discontinuity in the pressure.

42- (7O.15942) -Lp-r (?)

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The discontinuity appears in three different ways with each revolution of the cylinder

a) interrupting the Motov to be reproduced;

b) oblique displacement of the Motov;

c) Coverings of the Motov.

Moreover, these three errors can also occur at the same time.

The reasons for these errors are the main ones

L · either in the master copy or in the machine that allows this master copy to be transferred to the printing cylinder.

The present invention has the purpose of eliminating errors originating from the original.

The master copy also called "cliché" in specialist circles is known to appear in the form of a more or less transparent, rectangular image, its height is the same as the development of the printing cylinder and has a large, completely transparent edge area.

™ The relative location of the top and bottom edges of the

Clichés and the transparent edge surrounding the cliché are never accurate, and so are the two edges never exactly parallel; one must therefore attach two covers or masks so that these disturbing phenomena be eliminated. Unfortunately, even with great skill on the part of the operator, it is not always certain that the two covers for their part are exactly parallel to each other.

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are each other. In addition - even if one considers a parallel arrangement to be possible - the cliché itself can be slightly trapezoidal, and in this case will be a Part of the motif is covered by one of the covers and the connection when transferred to the cylinder is faulty.

Such errors are virtually uncontrollable on the cliché right now, and when they do occur, it persists the only remedy is to retouch the engraving of the impression cylinder by hand if the mistakes are not too are great.

On the other hand, there may be a tone difference between the top and bottom margins} when printing This error shows up very clearly, since it is characterized by a transverse border line between two surfaces with makes different tones noticeable »

The inventive method for dressing and testing a phot ο graphic master copy di «-. on -— eijiexl · Sensitized printing cylinder should be transferred »it is first and foremost that one is in a first step with With the help of two coupled twin projectors at the same time a point of the upper edge and the corresponding point of the lower edge of the original on a projection screen projected and brings the images of these points to coincide, then the two projectors parallel to Move original and retouch the original if the entire image is faulty. As each of the two twin projectors designs an inverted image of the projected original edge point, it is easy to understand that the

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simultaneously projecting a point of the upper edge and the corresponding point of the lower edge when they coincide of the two images of these points, the entire projection image, which also includes the images of the points from the Contains environment representing the reproduction of the critical zone of the printing cylinder on a large scale, i. do the one Zone in which the discontinuities appear if the original copy or the cliché is faulty.

In a second stage, a cover or mask strip is now placed along the lower and upper edge of the template in such a way that the mask stripe edges on collapse the screen in the projection; Then it will be retouch the original if the entire image has discontinuities. In a third stage one materializes on the transparent frame of the template, the extensions of the cover or mask strip edges by a Mask, for example by means of a line, and checks that the projection images of these two lines coincide and lie in the extension of the image of the two edges of the masking or masking strips

The lines or identification marks drawn in the process allow later, the cliché or the master copy to be arranged or set very precisely relative to the printing cylinder to which the motif is to be transferred.

For a better understanding of the invention, an implementation example will now be described in which this Example illustrative drawing is referred to; show in this drawing:

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1 and 2 are very schematic perspective views showing the essential phases or Recognize stages of the method according to the invention for preparing and checking a master copy permit;

Fig. 3 is a perspective view of a device for carrying out the invention Procedure;

FIG. H shows a vertical section, shown on an enlarged scale, through this device; FIG.

Fig. 5 is a section along the line V-V of Fig. 4, which is limited to the bracket of the lower projection device}

6 is a perspective, exploded view of the lower device, which allows the images of a point of the top margin and a corresponding one The point of the lower edge to coincide ο

As shown in the drawing, the usual "cliché" or a master copy 1, which is rectangular is assumed and is determined by its four corners A, B, C, D in the circumference, with a transparent border provided and applied to a likewise transparent surface, which consists of a transparent disk 3.

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It is assumed that the motifs to be transferred are given by the arrows k and 5? these arrows are arranged in such a way that when printing with the aid of an engraved printing cylinder, the tips of the arrows h and 5 would be opposite one another.

It is also assumed that all the tips of the arrows k lie on the edge AB of the copy original and all the tips of the arrows 5 lie on the edge DC.

If the cliché or the master copy is correct, the sides AB and DC are parallel, and each of the W arrows h corresponds to an arrow 5 'which lies on a line running perpendicular to the sides AB and DC. One of the purposes of the present invention is to check these two points.

For this purpose, a point B _{1 on} the AB side is projected onto a projection screen 6 with the aid of a projection device which is symbolically represented by its light source 7 and its lens 8; this projection device can be displaced or moved along a path running parallel to the cliché or to the master copy 1. Then you project with the help of a second Profe jektionsgerätes, which is also symbolized by its light source 9 and its lens 10 according to the first, on the screen 6 a point C _{1 of} the side DCj the two projection devices are rigidly coupled to each other for all transverse movements, they provide "Twin projectors" represent, and the axes of their lenses define a plane perpendicular to the direction of movement of the two devices.

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By inclining the axes of the lenses in a suitable way in the plane determined by you, the images B ^! and _{bring C 1} of points B ₁ and C ₁ to coincide; then you move the two projectors.

If the sides AB and DC of the cliché or the master copy are parallel to each other, each image corresponds of another point of the edge AB an image of another point of the side DC which coincides with the first point image.

However, if, for example, the vertical side AD of the cliché is smaller than the side BC, then the images A ^f ₁ and D ¹ ₁ , which correspond to the points A ₁ and D ₁ , are separated by a space (FIG. 1).

It is also possible that the sides AB and DC are parallel, but that the tip of one of the arrows is not on the corresponding side. In this case, the images B ¹ ₁ and C _{1 are} separated by a space. After the error has been discovered, the cliché or the master copy can be retouched immediately in order to make the error disappear} the same applies if the test reveals a difference between the tones of the edge part AB and the edge part DC of the cliché.

The adjustment of the cover or mask strips 11 and 12 does not present any difficulty if the cliché is perfectly correct and you proceed in exactly the same way as described above, that is, the marginal edge aa ^{1 of} the mask strip 11 with the side AB of the cliché to And the marginal edge 12 * of the mask

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Strip 12 with the side DC, whereby one checks on the projection screen by moving the twin projectors whether the projections or the ^{images given by the mask edges 11f} and 12 * coincide.

If, however, the sides AB and DC are not parallel, the masking or masking strips are attached in such a way that their strip edges 11 * and 12 * are parallel, one risking that part of the illustrated Subject is covered.

With reference to FIG. 2, it is assumed that the side AD is larger than the side BC of the cliché and that the side DC runs perpendicular to the plane which is given by the axes of the objectives} in this case the images of the tips lie of arrows 4 ¹ and 5 ^f do not coincide, since the edge 11 * of the mask strip 11, which is arranged parallel to the edge 12 * 'of the mask strip 12, covers the tip of the arrow h *.

Such errors can be suppressed by retouching the cliché or the master copy and the image obtained on the projection screen 6 is checked at the same time.

The edges or edges 11 * and 12 * of the mask strips limit the cliché or the copy! It can now be favorable to materialize their extension on the transparent peripheral edge of the cliché in such a way that in this way marks are obtained which sensitize a later setting of the cliché relative to the one to be exposed Allow printing cylinders with much greater accuracy.

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^{For this purpose, a line 13 is drawn on the transparent edge in the extension of the edge 11 f of} the mask strip 11, for example with the help of a drawing pen or scribing pen, the tip of which is placed on the cliché, and at the same time it is checked that the image 13 * of this line lies in the extension of the line XY of the two overlapping images of the marginal edges 11 and 12 ″ of the mask strips.

Then a second line 14 is drawn on the same side on the cliché in the extension of the marginal edge 12 'of the masking strip 12, and one checks whether the image 14' of this line on the projection screen coincides with the image 13 '. You can of course take this measure again on the other side of the cliché _{or similar}

A device will now be described which enables the method according to the invention to be carried out allowed, the aforementioned elements of this device retaining their reference numerals.

From Fig. 3 it can be seen that the glass pane 3 is held above and below by two cross members 15, their ends in cutouts 16 of the vertical upright one Reach in frame 17, which in turn can be held in a substantially vertical plane. The lower side 17 'of the frame 17 has at each of its ends an adjusting screw 18 which allows the inclination to vary the trusses 15 relative to the sides of the frame; the reasons for this will be given later «)

17 "on each of the upper and lower frame sides

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or 17 'of the frame 17, a sliding sleeve 19 can slide " The sliding sleeves 19 are in turn connected by two parallel rods 20, which are perpendicular to the upper and lower Side of the frame 17 running The connecting rods 20, which are designed as tubes, serve to guide two identical, adjustable slide 21 and 22, which can each be determined by tightening a screw 23.

Each of the carriages 21 and 22 is firmly connected to one of the ends of U-shaped support arms Zk or 25, the legs of which run on one or the other side of the disk 3 and enclose it on the outside.

The middle part of the support arm Zk lies above the upper edge 17 "of the frame 17» while the middle part of the support arm 25 lies below the lower edge 17 'of this frame.

The lens 8 of the upper projector is attached to the end of the leg of the support arm Zk , which extends between the pane and the projection surface, while the lens 10 sits on the corresponding leg of the support arm 25. The ends of the other legs of the support arms Zk and 25 are each firmly connected to circuit boards and 27, on which the light source 7 or 9 of each of the two projectors is fastened.

The sinkers 26 and 27 are connected to the carriage 21 and 22 via a horizontal axis 28, which is a Pivoting of the sinkers permitted. The pivoting of each of the sinkers and their support arms relative to the associated one

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Slide is limited, for example, in the following way: Each slide has a threaded bolt 29 »on one Spring 30 is seated, and through a longitudinal slot 31 one Extension 32 of the corresponding board protrudes and is provided with a nut 33 on the outside.

The springs 30 seek the carrier and sinkers in the To pivot the sense that the axes of the lenses 8 and 10 intersect; but by operating the nuts 33 is it is possible to move the point of intersection so that on the projection screen in the manner described above projected images cover each other.

The device described works in the following way. The cliché or the master copy is attached 1 on the glass pane 3 »for example with the help of adhesive tape, then the light source of one is switched on Projector, for example the upper one, and moves the entire movable assembly so that you can check can determine whether the edge AB of the cliché is substantially parallel to the horizontal sides of the frame; possibly" adjust to parallelism by turning one or the other of the screws 18.

Then you bring the entire movable assembly to side BC of the cliché and place the carriages accordingly the height of the cliché; then the carriage on the cross connections 20 with the help of Locking screws 23 set.

Now you turn on the light sources of the two projectors, and by operating the nuts 33 you leave

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the axes of the lenses 8 and 9 pivot such that the Images of points B and C are brought to coincide. The springs 30 play the role of brakes by they the approaches 32 with the elongated holes 31 on the nuts press on.

At this point, the setting of the device is finished, and the preparation or testing of the Clichés can be created in accordance with the method already described above by moving the entire movable, from the sliding sleeves 29 and the cross bars 20 connecting them are performed.

It goes without saying that the present invention is not limited to the manner of implementation described, which is shown in FIG the drawing was illustrated; the invention includes rather, all deviations in terms of shapes, building materials and dimensions.

For example, for clichés or master copies with large dimensions, the cliché can be attached on the glass pane by cutting the middle area of this cliché through the pane Openings attached to the Scheibr sucks.

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Claims (1)

Claims Μ.) Method for preparing and checking a photographic master copy that is to be transferred to a sensitized forme cylinder, characterized in that in a first stage with the help of two coupled twin projectors (7 »8 or» 9 »10) simultaneously a point of the upper edge (AB) and the corresponding point of the lower edge (DC) of the template (l) are projected onto a projection screen (6) and the images of these points are aligned, the two projectors are shifted parallel to the template and the templates are retus- chiert when the entire image faulty ISTJ that, in a second step, the mask strips (11, 12) along the lower and upper edge of the document attaching such a way that the images of MaskenstreifenräÄer _f coincide on the projection screen and the template retouched, if the entire picture Discontinuities have j that one in a third stage on the transparent frame of the template the extensions of the Maskenstre the edges are materialized by a mark or a line (13) and checked that the projection images of these two marks or lines coincide and lie in the extension of the image of the edges of the mask stripe 2. Apparatus for carrying out the method according to claim 1, characterized in that the master (1) can be fastened on a transparent disc (3) which is held in the plane of a frame (17), on the two parallel sides (17 ^r »17") a movable arrangement can slide which consists of two sliding sleeves (19) »two connecting rods (20) running perpendicular to the frame sides mentioned, on which two carriages (21, 109847/1300 22) are transversely guided, which are determined independently of one another • rierden, with each of the two carriages on the side of the transparent pane the light source (7 or 9) and on the other side the lens (8 or 1O) of one of the projection devices carries. 3. Apparatus according to claim 2, characterized in that each projection device (7 »8 or 9» 10) of a U = - ■ shaped support arm (24, 25) is carried, the legs of which extend on the one hand on the one hand and on the other hand on the other side of the disc (3) and that the light source (7 or 9) and the lens (8 or 1O) each sit on one of the ends of these legs. 4. Device according to one of claims 2 and 3 »characterized in that the carriage (21, 22) behind the Disc (3) are arranged » 5. Apparatus according to claim k, characterized in that the light source (7 or 9) of each projector is carried by a circuit board (26 or 27) which is fixed to the corresponding end of the U-shaped support arm (24 or 25) is connected and can be pivoted on the corresponding slide (21 or 22) via an axis (28) running parallel to the displacement of the movable arrangement. 60 device according to claim 5 »characterized in that that each carriage (21 or 22) carries a threaded bolt (29) on which a spring (30) is held and which is through an elongated hole (3 "O of an approach (32) of the corresponding Plate (26 or 27) extends therethrough and receives an adjusting nut (33). 109847/1300 7. Device according to any one of claims 2 to 6, characterized in that the upper and lower edges of the transparent pane (3) are held by cross members (15) the ends of which extend through longitudinal slots (16) of the vertical supports (frame uprights 17), that the lower traverse rests on the heads of two screws (18) screwed into the lower edge (i7 ^f ) of the frame (17), each of which is arranged at one of its ends ο 109847/1300