US2192924A - Printing method - Google Patents

Description

March 12, 1940. w.- w. MAHER ET AL PRINTING METHOD Filed Aug. 11, 1936 2 Sheets-Sheet 1 Eta! iza March 12, 1940. w. w. MAHER ET AL 2,192,924

PRINTING METHOD Filed Aug. 11, 1936 2 Sheets-Sheet 2 Patented Mar. 12, 1940 UNITED STATES PATENT OFFICE PRINTING METHOD New Jersey Application August 11, 1936, Serial No. 95,476

2 Claims.

The present invention relates to a method of printing by means of a flexible printing plate such as the regular zinc printing plate and has particular reference first to steps of producing zinc plates so that registration elements are included in the plate itself, such registration elements bearing definite relation to the printing design on the plate, and second, tothe use of a plate for printing in the printing press in which the registration elements are again utilized to accurately position the printing design relative to the surface being printed.

An object of the present invention is the provision of a method of producing a zinc plate or other similar printing plate so that it is equipped with registration elements which bear a definite relation to the printing design on the plate and by means of which the plate may be subsequently positioned and used in a printing operation whereby more accuracy is obtained with a saving in time and expense and with greater ease than by the usual shifting and adjusting operations attendant upon the usual printing press procedure.

Another object of the invention is the provisionof such a method for printing plate preparation and use wherein the registration elements are formed in the plate by punching through and making openings in the plate, such openings being utilized during the production of the plate for printing and during its subsequent use as a printing medium.

Yet another object is the provision of method steps including holding zinc printing plates and punching registration holes therein, thence placing the printing design in definite relation to the holes as by utilizing the holes for registration during its composition in a photo-composing machine so that different plates as so produced are exact duplicates, the holes of each individual plate being again used in the printing press for proper registration during subsequent printing from the zinc plate to the end that the work performed in the press will all be uniform, this being easily and quickly obtainable withoutthe usual need of preparatory adjustment or positioning of the parts during the different stages referred tom" Yet another object of the invention is the provision of a method of printing wherein there are produced printing plates having duplicate registration elements which make possible the use of the plates in printing sothat substitution of a different printing plate may be easily made in the printing press without disturbing the relative position of the design elements and so that perfect registration in printing with different plates as in a multi-color job may be obtained without need of adjustment, this feature adding greatly to the life of such printing plates and minimizing handling time in their setting into printing position within the printing press.

Numerous other objects and advantages of the invention will be apparent as it is better understood from the following description, which, taken in connection with the accompanying drawings, discloses a preferred embodiment thereof.

Referring to the drawings:

Figure 1 discloses schematically and in perspective a holding device and a punching jig or template for operation with a zinc printing plate, parts being broken back to disclose the relativ position of the zinc plate in the jig;

Fig. 2 is an enlarged sectional detail taken substantially along the line 22 in Fig. l and showing in addition to the holding device and zinc plate within the jig, a punching pin for forming registration elements in the zinc plate;

Fig. 3 is a transverse sectional view, largely schematic, of the principal parts of a photocomposing machine illustrating the holding of the perforated zinc plate during the application to its surface of the printing design;

Fig. 4 is a perspective view showing the step of developing a zinc plate after composition of the printing design upon its surface;

Fig. 5 is a side elevation of a plate cylinder of a printing machine illustrating the clamping o the zinc plate on the cylinder; and Fig. 6 is an enlarged transverse sectional view taken through the plate cylinder being substantially a section taken upon the lines 66 in Fig. 5.

vThe principal method steps contemplated in the present invention are suggested in the various figures of the drawings by certain elements and parts of machinery, these steps including the perforating of a zinc "printing plate as'fin Figs. 1 and 2 to provide registration elements in p the plate itself, thence comprising the design in a photo-composing machine ori the sensitized surface of the zinc plate as suggested in Fig. 3 after which the exposed plate is developed to bring out and fully setthe'design uponithe plate as indicated in Fig. 4, this design bearing a definite relation to the registration openings previously made in the plate and, lastly, asexemplified in Figs. 5 and 6, the accurateplac ng and registration of the zinc plate forgprinting as it means of which the jig element l4 may be lo-' cated on top of the holding device in an exact predetermined position. The jig element also is formed with a number of vertical bores l6 which are preferably disposed in straight lines parallel to opposite sides of the jig element.

The zinc plate I3 when it is placed in the holding device II is usually already prepared with its sensitized surface indicated by the numeral I! (Fig. 2) which ordinarily will be on the top surface of the zinc plate as the latter rests in position on the flat surface of the holding device H and inside of the locating pins l2.

While the zinc plate I3 is thus confined between the elements |||4, registration holes I8 are punched through the plate. This may be conveniently performed by a punching pin 2| which may be inserted in each hole l6 and the perforating end of the pin may be forced through the zinc plate by a sudden blow as by means of a hammer 22. The lower holding device plate II is provided with aligned clearance openings 23 there being one opening for each bore 6 of the upper plate I4. A bushing 24 may be inserted in the upper end of each of the openings 23 andthe center bore of the bushing is such as to snugly receive the punch end of the pin 2| when it is driven down through the zinc plate.

In this manner a plug 25 of the zinc plate is cut out by the descending punch pin and falls through the clearance opening 23 in the holding device. This perforating action punches the registration holes l8 in the zinc plate and all of the registration holes bear a definite relationship one to the other as they are in turn gauged as to position by the holes I6. In this manner the zinc plate prior to receiving its design is provided with registration elements which are preferably disposed along two opposite edges of the plate.

The zinc plate with its aligned registration holes may then be transferred to a photo-composing machine. There are a number of well known types on the market and accordingly only a brief reference will serve the present purpose. Such a'machine is illustrated in part in Fig. 3 of the drawings and may comprise a support board or frame 3| on which the zinc plate is positioned with its sensitized surface facing away from the engaged frame. With the present type of zinc plate I3 having the registration holes l8, the plate may first be hung on upper pins 32 carried in the frame 3|. These upper pins 32 are arranged in a horizontal row and are spaced the same distance apart as are the openings in the zinc plate.

In order to hold the top half of the zinc plate firmly against the face of the supporting frame one or more suction cups 33 are used, these being located in a pocket 34 cut in the face of the frame 3|. The interior of the suction cup is connected with a source of vacuum as is usual with suction cups. A nipple 35 is screwed into the frame back of the suction cup and a vacuum hose may be clamped onto the nipple by means of which the desired suction may be drawn on the suction cup.

It is desirable that the zinc plate be pulled taut as it rests in the photo-composing machine and accordingly there are provided a set of lowerholding pins 4| which engage within the registration openings l8 on the lower edge of the zinc plate. The pins 4| are also arranged in a row and are spaced the proper distance so that all of the lower edge of the zinc plate is engaged by the lower row of pins.

The pins 4| are carried on a slide 43 which is adapted for vertical movement within spaced slideways or guideways 44. These slideways are formed in part by side plates 45 which are bolted to the rear of the frame 3|, the side plates holding the slide 43 in sliding position. An operating rod 46 secured to the lower end of the slide provides connection with any suitable moving part to allow for the necessary pulling down of the slide and the drawing taut of the zinc plate.

One or more suction cups 41 are also carried on slide 43 and provide holding means for pulling the lower portion of the zinc plate back against the face of the frame 3|. The interior of each suction cup 41 communicates through a nipple 48 on which a suitable vacuum hose 49 may be mounted. When vacuum is applied the suction effective at the face of the suction cups 4! with a zinc plate in place holds the bottom of the zinc plate back against the face of the frame.

The design which is the result of the operations of the photo-composing machine is impressed or reproduced in the usual way on the sensitized face ll of the properly positioned zinc plate. This design may consist of a single pattern or may be composed of a duplication of unit patterns. In obtaining the composite type of design the photo-composing machine properly locates each light impression of each unit pattern in the proper registration, this feature of photo-composing machines being very accurate. The action of composing a design is so well known that it is thought further explanation is unnecessary other than to suggest that a source of light 5| may be carried in a suitable housing 52, and properly held on a movable frame 53. The design to be printed on the sensitized face of the. zinc plate may be carried on a screen 54. y

In order to finish the zinc plate so that it can be used for printing it is removed from the photocomposing machine and is developed, etched, fixed, etc., in the usual manner, Fig. 4 indicating graphically or schematically this operation. There is shown in this figure a pan 55 for holding a suitable chemical or liquid 56 and the finished zinc plate I3 is shown as being withdrawn from the chemical solution. This figure also shows the composite design which may be formed by a number of individual units 51. By reason of the accurate printing of the design units in the photocomposing machine each unit bears a definite relationship to the other units and to the registration openings l8 on the two edges of the plate.

In order to suggest the step of printing from the prepared zinc plate l3 there is disclosed, in Figs. 5 and 6 of the drawings, a printing cylinder 6| which may be substantially the regular form as used in the ordinaryrotary printing press for carrying the regularzinc printing plate as in offset printing.

The printing cylinder 6| is provided with the I usual recess designated by the numeral 62 in which a clamp block 63 is secured in the usual manner by screws 64. This clamp block carries a series of aligned pins 65 which are spaced the same distance apart as the registration openings l8 in the zinc plate. The upper edge of the zinc plate I3 is placed on the clamp block 63, the registration openings I8 being positioned over the pins 65 so that the upper edge of thezinc plate is held in exact position relative to the printing cylinder 6|.

The removable clamp bar 61 is then placed over the edge of the zinc plate, this bar having a series of holes 68 which are spaced apart the same distance as the registration holes in the zinc plate so that the clamp bar is located on the pins 65. This clamp bar is held intheusua'l manner as by clamp bolts 69.

Zinc plate I3 is then pulled taut and is caused to adhere to the surface of the printing cylinder. Its opposite or lower edge is confined in the usual clamping unit which is best illustrated in Fig. 6 and which is disposed in a longitudinal recess II. I

This clamping unit comprises a clamping block 12 which carries a series of pins 13 which like the openings 65 are located in a straight line and are spaced apart the same distance as the registration openings I8 of the zinc plate. The lower edge of the zinc plate is located over the pins I3 and this edge is then held down by a clamping bar 14. The clamping bar 14 in turn is secured in clamping position on the clamp block by bolts 15.

Both the clamp block I2 and the clamp bar I4 are yieldingly supported. on a pivot shaft I! which is carried in a bracket I8, bolted to the printing cylinder at the base of the recess 1|. A plurality of spring barrels 8I are disposed in bores 82'which are formed in'the clamp block 12 and springs 83 are seated in the bottom of these bores. The springs are confined in the bores by the spring barrels 8 I. By means of this construction the springs 83 exert a force on the block I2 and clamp bar 14 which in turn pull the zinc plate taut over the surface of the printing'cylinder.

Inasmuch as the printing design 51 carried on the zinc plate I3 is afiixed thereto relative to the registration elements I5 and the zinc plate is located in both photo-composing machine and printing machine by the same registration elements, the printing design 51 when the plate is located on the printing cylinder 6| is always presented to the surface to be printed at an exact predetermined place. This insures that the design on duplicate plates made at diiferent times or on cooperating plates used in succession on the same surface being printed as in a multi-color job, will always be perfectly aligned on the surface being printed without adjustment of the plate on the printing cylinder, the registration elements affording a labor saving and positive means of locating the plates on the printing cylinder with assurance of interchangeability and accuracy in printing results.

It is thought that the invention and many of its attendant advantages will be understood from the foregoing description, and it will be apparent that various changes may be made in the steps of the process described and their order of accomplishment without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the process hereinbefore described being merely a preferred embodiment thereof.

1. The method of preparing a plurality of color printing plates for a multicolor design in a printing machine, which comprises providing individual color plates each with a plurality of registration elements disposed in predetermined positions, and thereafter successively locating said plates by means of said registration elements upon a frame having a design carried thereby for the purpose of imparting the design to said plate, holding the plate upon said frame and photographically imparting a design of the individual color thereto during the holding operation, then utilizing said registration elements to successively locate each of said plates in predetermined position upon a printing instrumentality prior to a printing operation, and then printing from said plates.

2. The method of preparing a plurality of color printing plates for a multicolor design in a printing machine,'which comprises providing individual color zinc plates each with a plurality of registration elements disposed in predetermined positions, and thereafter successively locatin'g said zinc plates by means of said registration elements upon a frame having a design carried thereby for the purpose of imparting the design to said plate, holding the plate uponsaid frame and photographically imparting duplicate designs of the individual color thereto during the holding operation, then utilizing said registration elements to successively locate each of said plates in predetermined position upon a printing instrumentality prior to a printing operation, and then printing from said plates. I

WILLIAM W. MAKER. CARL G. SCHOOF.

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