US1954753A - Projection apparatus for making photomechanical printing plates - Google Patents

Description

R. A. GLASER April 10, 1934.

PROJECTION APPARATUS FOR MAKING PHOTOMECHANICAL PRINTING PLATES 6 Sheets-Sheet 1 Filed June 14, 1929 444"? dtm R. A. GLASER April 10, 1934.

PROJECTION APPARATUS FOR MAKING PHOTOMECHANICAL PRINTING PLATES Filed June 14 1929 6 Sheets-Sheet 2 Quao/ph 6/056/1 rm 2 W A ril 10, 1934. R. A. GLASER 1,954,753

PROJECTION APPARATUS FOR MAKING PHOTOMECHANICAL PRINTING PLATES Filed June 14, 1929 6 Sheets-Sheet 3 R. A. GLASER PROJECTION APPARATUS FOR MAKING PHOTOMEGHANICAL PRINTING PLATES April 10, 1934.

.Filed June 14, 1929 6 Sheets-Sheet 4 gwuemtoz April 10, 1934.

R. A. GLASER 1,954,753

PROJECTION APPARATUS FGR IAKING PHOTOMECHANICAL PRINTING PLATES l I i Filed June 14, 1929 6 Sheets-Sheet 5 gwventoz M (bond- UM M abtomaq Eudo/ph J57. yaserg R. A. GLASER April 10, 1934.

PROJECTION APPARATUS FOR MAKING PHOTOMECHANICAL PRINTING PLATES filed June 14, 1929 6 Sheets-Sheet 6 @uda2/1 13 67056;

M EMA. (Bay/w... 'M 06mg! 50 will be apparent to Patented Apr. 10, 1934 PROJECTION APPARATUS FOR MAKING PHOTOMECHANICAL PRINTING PLATES 'Budolph A. Glaser, Cleveland, Ohio, assignor, by

assignments,

meme trustee to Gardner Abbott,-

Applicatlon June 14, 1929, Serial No. 871,002

lOCIaims.

My invention relates to a new and improved projection apparatus especially adapted for use 1 making photomechanical printing plates, wherein images may be projected directly upon a printing plate or other sensitized member in proper relative position and exactly the right size, and aims generally to improve existing methods and apparatus intended for this purpose.

1 In the art of making printing plates photographically for instance, as described in my copending application Serial No. 295,266, flled J y 25, 1926, the image, which may be contained either in a photographic negative or positive,

depending upon whether a positive or negative printing plate is desired, is projected by means of the actinic rays of a powerful light, preferably especially designed for a projecting machine, through a suitable lens directly upon a sensizo tized surface of a suitably grained printing plate.

' The photographic image to be produced may be either a continuous tone or half-tone reproduction, and if continuous, may be broken up into dot formation by being projected through a halftone or mezzographic screen, as hereinafter described.

In the preparation of a set of multi-color printingplates, for example, a separate plate is required for each color used, and hence if the printing is to be done by a six color process, six separate printing plates must be prepared. If the printed copy is to be an enlargement of the original, it is apparent that the extent of enlargement must be exactly the same for each plate, and the subject must be properly and accurately positioned on. eachplateto insure accurate registry in the final printed copy.

One of the principal aims of the present invention is the improvement of the method .of

and apparatus for insuring the speedy and accurate projection of images for a set of printing plates, so that accurate registryin the final copy is assured.

v Another aim is to locate different-images forming the subject upon each plate at the same relative spacing both vertically and horizontally to insure proper registry of the variousfplates.

Other aims and advantag'esrof the invention those skilled in the art, having reference to the following moredetailed description and to the accompanying drawings, wherein, I have selected for illustrative purposes, one practical and successful embodiment of my invention.

' one part thereof relative to another after the proper working (Cl. 8H4) In the drawings Fig. 1 is a partial side elevation of the projecting apparatus, parts of the frame being broken away to get the view within the compass of the sheet;

Fig. 2 is a sectional view thereof taken on the line 2--2 of Fig. 1, showing the plate holder in elevation;

Fig. 3 is a horizontal sectional view of the plate holder taken on the line 3-3 of Fig. 2;

Fig. 4 is a horizontal sectional view oi. the same taken on the line 4-4 of Fig. 2;

Fig. 5 is a sectional view taken on the line 5-4 of Fig. 1, showing the projecting unit carriage in end elevation;

Fig. 6 is a side elevation of the micrometrical adjustment and lock for the projecting unit table;

Fig. 7 is a detail view thereof taken on the line 7-7 of Fig. 6;

Fig. 8 is a vertical, sectional view of the plate holder and its carriage taken on the line 8-8 of Fig. 2;

- Fig. 9 is a detail sectional view of the plate holder carriage lock taken on the line 9-9 of i 2;

Fig. 10 is a detail view of the projecting camera gauge; I

Fig. 11 is an enlarged plate holder;

Fig. 12 is a detail valves thereof;

Fig. 13 is a detail sectional view taken on the line 1313 of Fig. 12; and

Fig. 14 is a detail view of the yielding, leveling and compensating devices for the chassis.

In the particular embodiment of the invention selected for illustrative purposes in the annexed drawings, the apparatus -is preferably mounted upon a suitable chassis 10, herein illustrated as comprising upper and lower frame sections, 11 and 12, respectively, of'structural material, such front elevation of the sectional view of one of the .as angle irons, suitably braced, and interconnected as by'uprights 13, so as to form a rigid supporting structure. Obviously any suitable form and arrangement of supporting elements 11,

, 12 and 13, may be adopted, which provides a rigid support for the projection apparatus, hereinafter described, so as to prevent movement of various parts have been set and clamped in their positions, as will be more fully described later. 1

Yielding, leveling and compensating devices are provided for the at desirable points, as, no

for instance, at or adjacent to the respective corners of the chassis 10, so as to absorb and compensate for vibrations and disturbances of the floor of the building in which the apparatus may be used, while at the same time providing for the accurate leveling of the chassis. The resilient supporting of the frame, advantageously, may be accomplished by,a coil spring 14 (see Fig. 14) centered in the frame and one of the structural members thereof so as to support it resiliently. The coil spring 14 is in turn supported by a cushion 15, as of sponge rubber, capable of absorbing minor vibrations, and a protecting plate 16 for the rubber, is interposed between the spring 14 and the rubber cushion 15. The entire chassis may be levelled accurately by suitable leveling devices, as for instance, opposed wedges 17,, which may be adjusted relatively to each other lmtil the chassis is accurately levelled, as indicated by a plumb level applied to the chassis, as is well understood in the art.

The lower frame section 12 of the chassis 10 carries a pairof longitudinally extending rails 18, supported upon structural members 19, rigidly connected to the lower frame section 10, these rails 18 providing a trackway for the lamp carriage 20 and projection unit carriage 21, each of which is provided with grooved rollers 22 coacting with said rails.

One of the structural members 19, supporting the rails 18, is provided with a scaled clamping bar 23 suitably connected rigidly therewith (see Figs. 5, 6 and '7) and a plurality of serially numbered clamping lugs 24 are slidably supported on the bar 23 and are adapted to be independently clamped thereto as by clamping screws 25. The upper end of each lug 24 is suitably shaped, as at 26 (Fig. '7) to receive and lock, as by a pin 27, one or the other of the depending guides 28 adjustably carried in the respective carriages 20 and 21.

Advantageously, the lugs may be provided each with an index finger to register with the scale readings on the bar 23, so that the exact position of the carriage may be determined and recorded.

The lamp carriage 20 rigidly supports a lamp 29, preferably a high power rotating carbon arc lamp, such as disclosed in my copending application, Serial No. 295,266, filed July 25, 1928, the lamp casing being provided with a stack 30 having a telescopic sliding connection with a flue 31 whereby gases generated within the lamp casing may be withdrawn. The lamp carriage 20 is provided at its base with a clamp 32 for clamping its guide 28 in the desired adjacent lug 24, there being a Vernier scale 33 on the guide and base to permit of accurate setting and adjustment.

The projection unit carriage 21 may be constructed like the lamp carriage 20, and is provided with a similar clamp 34 for clamping its guide 28. Either or both of these clamps 32 and 34 may be provided with a micrometer adjustment 35 (see Fig. 6) so that accurate settings and adjustments of the carriages may be assured.

Carried by the carriage 21, in fixed horizontal alignment with the lamp 29 is a condensing lens 36. plate holder 37 and objective lens 38, of conventional construction and arrangement suitably supported and housed as will be apparent to those skilled in the art. As is well understood, it is necessary to adjust the focusing lens toward and away from the plate holder 37, which carries the photographic plate, and for this purpose the objective lens carriage 39 is slidably mounted upon guide bars 40 rigid with the carriage .21, and is engaging the underside of the lens 38 relative to movable therealong by means of a pinion 41 on a shaft 42 journaled in the lens carriage 39, and engaging with a fixed rack bar 43 on the carriage. (See Fig. 10).

A hand wheel-44 on the shaft 42 is provided to permit of adjustment of the lens carriage 39 along the guide bars 40, and this hand wheel 44 is provided with a scale 45, cooperating with an index finger 46 so that accurate adjustment of the photographic plate in the plate holder 37 may be attained and recorded. When the lens 38 is in proper adjusted position, its carriage 39 may be clamped upon the guide bar 40 by means of a clamp 4'1.

In the method of making photomechanical printing plates according to my invention, the photographic image is projected directly upon the sensitized surface of a metal printing plate, and accordingly my present invention provides means for holding the plate and adjusting it with precision relativeto the projection apparatus. Fur thermore, in many instances a number of different subjects are placed upon a singlelarge printing plate, and it obviously is necessary to provide for vertical and transverse movement of the printing plate holder and locking means for locking it in numerous adjusted positions so as to insure proper registry of the different subjects on the several plates.

In the embodiment of the invention illustrated herein, the printing plate holder 48 is mounted on a vertically movable carriage 49 slidable on vertical standards 50 of a transversely shiftable carriage 51 mounted to slide transversely on upper and lower'supports or tracks 52-53 respectively carried by the uprights 13; the plate holder being counterbalanced by means of counterweights 54 connected to the vertically movable carriage 49 by means of cables 55 trained over pulleys 56 on the transversely shiftable carriage 51 so as to permit it to be shifted vertically or laterally with ease.

The printing plate holder 48 may advantageously be locked in a vertically adjusted position with respect to the axis of the lens 36 and 38 by means of a locking bar 5'7, pivoted in a bushing 58 secured on the transversely shiftable carriage 51 and engaging in one of a plurality of tapered grooved split collars 59 adjustably fixed to an adjusting rod 60 journaled in bushings 61' on the rear side of the vertically movable frame 49. The operator having determined in advance the vertical position of the printing plate for the particular work to be done, one of the collars 59, which may be serially numbered, is properly adjusted on the adjusting rod 60, which may be marked with a scale, and is locked therein in such position by a suitable clamp 62. The frame with the metal printing plate thereon may be shifted vertically along the standards 50, manually, until the previously adjusted and locked collar is in horizontal alignment with the locklng bar 5'7, when it may be locked in proper position vertically. Accuracy of adjustment is permitted by a micrometergauge 63 and screw on the lower end of theadjusting rod.

Similar means are provided for properly ad-' justing and locking the printing plate holder in precise predetermined positions transversely of the axis of the lens 36 and 38, and as shown in Figs. 2, 3 and 9, a suitably graduated adjusting rod 64, provided with a micrometer screw and scale 65, similar to that above described, is journalled in bearings 66 on the lower part of the transversely movable carriage 51 to bring the during the projection which tracks project iatera projection 1,954,753 I 1 3 pre-set collars a: into registry with the locking dicated at 8, provides a support for the haltbarqflspivotedtoanxedsupportonthechassis tone 10. Clamp screws 69 may advantageously be ported from-the upper track provided for clamping the micrometer screw rods rollers on the upper From the above it is apparent that the print ing plate holder may be accurately and quickly positioned in proper position vertically and transversely oi the axis oi projection, and be rigidly locked in such position during the entire operation for the printing accurately reto any pre-set position by virtue of the collars on the adjusting rods and micrometrical feed therefor.

In the projection of photographic images upon printing plates, particularly when making a series of plates for multi-color process printing, it is necessary that each of the plates be accurately positioned on the holder and flrmly held thereon of the image. This is advantageously accomplished by the plate holder shown herein (see Figs. 2, 11, 12 and 13).

hold the plate tightly in position.

The respective partitions separating each inner compartment from itsimmediately surrounding compartment, are each provided with a passageway 74 normally closed by a spring any series of compartments from the innermost outwar y, and the source of suction. I

As iswell understood in this art, the halt-tone printing image for pictorial representations is a dot formation, and according to my process such a printing image may be produced on the metal printing plate either by projection through a screen produced photographic plate (i. e. a halttone or other screened negative or positive) or by projection from acontinuous tone photographic plate and through a halt-tone line screen or mezzograph grain screen of the printing plate. For certain classes or work the latteris preferable, and accordingly my present invention provides for means for supporting the screen in proper position in front or the printing plate holder. As shown (see Figs. 1, 2 and 8) the printing plate holder casing 70 is provided along its upper and lower edges with tracks '17, conveniently formed of angle iron, beyond the ends of the casing 70 to permit shitting of the screen and screen holders laterally beyond the front'of the casing 70. e screen holder, generally inpositioned in front holder in position.

The advantages oi my invention reside chiefly necessity oi. highly paid skilledartists.

As has been stated, accuracy and precision in the projection of images upon printing plates are essential for/multicolor process printing, and another advantage is the certainty with which any number of identical reproductions may be made of one or a series of negatives by establishing the relative positions of the lamp, lens, negative and plates, and clamping them securely in such position so that the several color separation images may be projected upon their respective printing plates under identical conditions.

ermore, when it is necessary to make new plates to take the place of spoiled ones, in the manufacture of printing plates for multi-color process printing, such new plates must correspond exactly in size, enlargement and detail with the other plates. of that set in order that accurate registry of colors in the printed copy will result, and it is important, in such case, that the apparato correspond with precision to the original setting of the apparatus for the projection on the original plates of that set, otherwise satisfactory printed work cannot be produced. In the operation of the apparatus, an accurate recordlifwthe relative positions oi the various movable parts of the apparatus may readily be made, so that when retakes are required, the requisite precise relative positioning of the parts may be restored.

For example, if in connection with each job, the operator makes a record of the position of the lamp carriage 20, of the projection carriage 21, of the objective lens, and the vertical and erse positions after having determined the proper adjusted positions of these relative parts, should it become necessary, at a later time, to remake one or more oi the plates, the apparatus may be readily reset with precision, so that absolute registry of all colors in the printed copy will be assured.

some instances, it is desirable to project 'a plurality of different images upon a single printingplate, and accordingly it becomes necessary toshift each print plate vertically or laterally or both for each respective image. For this purthe plurality of locking collars on the respective adjusting rods 60 and 64 may be predetermincdly set, and successively locked axially of the projection axes by the locking bars 5'7 and 68, tom; the corresponding portions-of the plate in proper alignment with the lens for-projecting the successive images upon each plate.

of the printing plate holder Other advantages of the invention will be readfly apparent to those skilled in the art to which the invention relates.

1. In apparatus of the character described, a plate holder, fixed guide means therefor, a rod parallel to said guide means and a plurality of like slides adjustably mounted thereon, means for fixing said slides in adjusted position on said rod, respectively, a detent for engaging one or another of said slides and holding said plate holder in adjusted position, and micrometric means for exactly positioning said detent.

2. In apparatus of the character described, a

movable holder, a rod secured thereto, split rings movably. mounted on said rod and screwsfor clamping them in position thereon, a stationary bracket having an orifice through which said rod and rings may pass, and detent means carried by said bracket for locking it to a split ring to secure said holder in place.

3. A flexible plate holder having rollers for supporting it on a horizontal track, vertical guides for adjusting the holder up and down, a fixed bracket, a rod carried by said plate holder and passing through said bracket, slidable means on said plate holderv rod, means for clamping-said slidable means, and means onsaid bracket for engaging said slidable means and looking it and said plate holder in adjusted position, said rod being provided with screw threads, whereby rotating it will give it a slight endwise movement for quick manipulation.

4. A device for direct projection of images in the preparation of plates for multi-color printing in which great precision is required comprising a substantially rigid cage-like frame made up of rigid structural members suitably braced, rigid track members supported in said frame, projection apparatus mounted for longitudinal movement on said track members, means for rigidly clamping the parts of said projection apparatus in precise, determined position with respect to said frame, micrometric means whereby each of the parts of said projection apparatus may be moved and replaced with precision in any determined position, a plate holder carrying structure aligned with said projection apparatus and adapted to be rigidly connected to one end of said frame, means providing for micrometric adjustment of the plate-holder transversely of, and vertically with respect topsaid structure and frame, means for clamping said plate holder in:

determined adjusted position to hold it rigid with respect to said projection apparatus, and means for rigidly holding-a plate in said plate holder in determined position with respect thereto and for maintaining it in said determined position during adjusting movement of said plate holder, said means insuring accuracy of micrometric replacement of the parts in any determined relative position, whereby a plurality of images may be accurately located on each of a plurality of color separation plates.

5. As part of a projection apparatus of the character described in claim 4, the plate holder carrying structure comprising a pair of vertically spaced tracks rigidly mounted in, and transverse ly of, the end of a sup rting frame, a plate holdmounted on said trans= verse tracks,

to said tracks and frame, a pair of rigid vertical track members carried by said carriage, a plate holder adjustably mounted on said vertical tracks, micrometric means whereby said plate holder may be precisely positioned relative to said plate holder carriage, and means whereby a plate may be held rigidly in said plate holder in determined position with respect thereto during all adjustment and readjustment of said plate holder and carriage.

6. A device for direct projection of images in the preparation of plates for multi-color printing in which great precision is required comprising a substantially rigid cage-like frame made up of rigid structural members suitably bracer, rigid track members supported in said frame, projection apparatus mounted for longitudinal movement on said track members, means for rigidly clamping the parts of said projection apparatus in precise, determined position with respect to said frame, micrometric means whereby each of the parts of said projection apparatus may bemoved and replaced with precision in any determined position, a plate holder carrying structure aligned with said projection apparatus and adapted to be rigidly connected to one end of said frame, means providing for micrometric adjustment of the plate holder transversely of, and vertically with respect to, said structure and frame, means for clamping said plate holder in determined adjusted position to hold it rigid with respect to said projection apparatus, a counter-balance for said plate holder comprising cables extending from said plate holder over pulleys arranged above said frame and weighted at the ends, and means for rigidly holding a plate in said plate holder in determined position with respect thereto and for maintaining it in said determined position during adjusting movement of said plate holder, said means insuring accuracy or micrometric replacement of the parts in any determined relative position, whereby a plurality of images may be accurately located on each of a plurality of color separation plates.

7. In a device of the class described, means for accurately positioning a part alternatively in one or another of a plurality of predetermined positions relative to another part comprising a plurality of clamping lugs adapted to be rigidly locked to 10116 of said parts to comprise a plurality of predetermined fixed positions, a micrometrically adjustable element carried by said other part, and interengageable means carried by said clamping lugs and micrometrically adjustable elements, so that said micrometrically adjustable elemen may be alternatively engaged with one or another of said clamping lugs to approximate the relative positioning of said parts in one or another of said predetermined positions and be itself adjusted for micrometric relative positioning. thereof.

8. In a device of the class described embodying two parts, one of which is mounted for movement with respect to the other and parallel thereto, means whereby the parts may be precisely positioned in one or another of a plurality of alternative positions with respect to each other comprising a plurality of clamping lugs adapted to be lccked to one of said parts to present a plurality of predetermined fixed positions, an element rigidly positioned with respect to the other of said parts, a member mounted for independent 1 micrometrically regulated movement with respect to said rigidly postioned-elements, only in the directions of relative movement of said parts and interengageable means carried by said clamping lugs and member. I 1

9. In a device of the class described embodying a frame and a part movable longitudinally of said frame, means for clamping said part precisely in a predetermined position relative to 'said frame, comprising a clamping lug adapted to be locked in one or another of a plurality of fixed positions with respect to said frame, a member,

ing a frame and a part movable longitudinally of said frame, means for clamping said part precisely in one or another of a plurality of predetermined positions relative to said frame, comprising a plurality of clamping lugs adapted respectively to be locked in a plurality of fixed positions with respect to said frame, a member carried by said movable part and arranged to be micrometrically adjustable back and forth in the direction of relative movability of the part and frame, and means on said member engageable with one or another of said lugs.

RUDOLPH A. GLASER.

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