US2052556A - Multicolor printing - Google Patents

Description

Sept. 1, 1936. A. B. DAvjs MULTICOLOR PRINTING Filed Oct. 19, 1932 2 Sheets-Sheet 1 y e f 2"e .llllllllllLlnllll J W N Q Inveniaf' 4 rfl/rhu/ B.Davis wi-lamggs 2 Sheets-Sheet 2 Filed Oct. 19, 1932 Patented Sept. 1, 1936 UNITED STATES PATENT OFFICE 2,052,556 I UL'rrooLoa ranv'rme Arthur B. Davis, Springfield, Ohio ,Appllcation October 19, 1932, Serial No. 638,493

Claims. (01. 101-174) This invention relates generally to multi-color printing and has more particular reference to the manner in which the plates for printing different colors are mounted in order to obtain 5 proper color register.

' The general object of the invention is to provide a novel'construction of multi-color printing plates and a mounting therefor for obtaining a higher degree of accuracy in color registration than has been possible heretofore and to reduce the cost of manufacture of the plates and the time. during which the press is out of service in preparing the same for printing of an issue.

In carrying out the foregoing object, the invention contemplates forming on the different plates in exactly corresponding positions relative to their type-faces positioning devicesadapted to enact or interengage in a fixed relation with cooperating devices on the respective plate supports 29 of the printing press and thereby establish a predetermined positional relation between the different type-faces automatically as an incident to' placing the plates in the press.

The .invention also resides in the manner of forming the positioning devices on the difierent color plates before mounting thereof in the print-- ing press. Other objects and advantages of the invention will become apparent from the following detailed description taken in connection with the accompanying drawings, in which- Figure l is a diagrammatic end view'of theimpression and plate-supporting cylinders of a multl-color printing press.

Fig. 2 is a fragmentary plan view of one of the plate cylinders supporting one of the color plates in accordance with the present invention.

Fig. 2a is anenlarged fragmentary sectional view taken along the line i -2 of Fig. 2.

Fig. 3 is a section taken along the line 3-3 of Fig. 2.

Fig. 4 is a perspective view of a templet used for locating the securing devices on the different color plates.

Figs. 5 and 6 are views of two diiferent color plates in the course of formation. 7

Figs. 7 and 8 illustrate the manner of forming the positioning devices on the plates.

' Fig.9isaplanviewofafixtureusedintrim- 5o s etrn n a' As shown in Fig. 1, the multi-color printing presses commonly used in present practice are q pped with a plurality of cylinders 6 on which plates 1, 8, 9' and ill for prmting the four basic 55 colors or special colors are mounted. The cy1- finders are spaced circumferentially around a packing or impression cylinder II and rotated in exactly timed relation to each other and the packing cylinder by suitable power driven gearing. As is well understood in the art, exact color reg- 5 istratlon will be obtained during printing in the press above described when the plates are so positioned on their respective cylinders that correspondingly located points on different plates come directly opposite or coincide with the same point 10 on the paper while successive impressions are being taken. Under such conditions, there will be no overlapping of the matter printed by different plates where difierent color areas meet along a common line or where different colors 15.

are combined in the same area.

In the embodiment of the invention selected for purposes of illustration, each plate comprises a rectangular area of type l2 carried by and standing out-in relief on one side of a sheet i3 which herein comprises an ordinary electrotype shell having the type cavities M on the back side thereof filled with suitable reinforcing material l5. The type-carrying sheet or plate is supported in the press upon one of the cylinders ll through the medium of a backing member conforming to the curvature of the cylinder and fastened securely but detachably thereto so as to permit the plate assembly to be shifted across the cylinder surface as may be required in 80 some instances in order to compensate for slight inaccuracies in color registration. Preferably, the backing member is made in two plate sections i1 and i8 fitting together in edge-to-edge relation at a hinge joint l9 so that the section 35 Il may be swung upwardly away from the cylinder as shown in dotted outline in Fig. 3 while the section I8 remains fixed to the cylinder. Means such as lugs I!" on the section l8 receiving the edge. portion of the section ll be- 40 tween them are employed to hold the two sections against relative movement in a direction longitudinally of their pivotal axis. For a purpose to later appear, the backing members for the diflerent plates have the same dimensions. 45

A definite positional relation is established between the backing member and the cylinder in advance of mounting the type plate thereon. For this purpose, the width of the section l8,

that is the dimension perpendicular to the direction in which the plate is carried by the cylinder, is made greater than that of the width of the type sheet and the edges projecting from Opposite sides of the sheet are clamped against the cylinder by bars zu each bearing at opposite type-face is definitely located relative to the'cylends against one edge and the cylinder and drawn downwardly by a screw 22 threading into blocks seated in the regular T-shaped cylinder grooves 23.

In the present instance, each type-carrying plate is fastened securely to the backing member by being stretched over the surfaceof the latter in the direction of motion of the member by the cylinder. For this purpose, .the plate is formed with devices adapted to interengage with cooperating devices on themember and receive the tensile force which preferably is derived by relative movement between the two sections [1 and it of the backing member. Preferably said devices are in the form of shoulders extending along opposite ends of the plate and hereincomprise flanges 24 formed by bending the marginal end portions of the metal sheet l3 away from the type-face and reversely to form inturned portions 25. The spacing of the flanges 24 is slightly less than the length of the backing member. when the sections l1 and I8 are in alinement so that the required stretching action is obtained.

To mount the plate upon the backing member, the section I1 is swung upwardly into the position shown in dotted outline in Fig. 3 after which the plate is placed on the member with the fianges-24 and the inturned portions thereof extending around the remote edgespf the sections IT and I8. Then the section I1 is swung downwardly against the cylinder causing the type-carrying sheet to be stretched firmly over the surface .of the backing member and thus anchored in the cylinder. Finally clamping devices 26 are tightened down with their edges overlying the marginal edges of the plate assembly. ,The latter is thus fastened securly to the cylinder but may be shifted relative thereto 'as may be desired by first loosening the screws 22 and the clamps 26. i

As an incident to fastening each type-carrying plate upon the backing member as above described with the section l8 secured to the cylinder, it will be observed that a definite positional relation is established between the cylinder and the type-face in the direction of movement of the latter by the cylinder. This relation is determined by the positions of the flanges 24 relative to the type-face which flanges there fore constitute positioning devices as well as a means for enabling the backing memberand plate to be fastened together. To provide means for establishing a similarly fixed positional re-' inder. d p

In accordance with the present invention, the flanges 24 and the ends thereof are located on the plate for-printing one color .in exactly the same relation to the type-face thereof as the flanges of the sheets for printing the other colors with which the first mentioned color is to register. This is accomplished before attachment of the sheets, to the press through the use of a templet (Fig. 4), one of which is formed for the set of plates employed for printing one page. In the present instance, the templet comprises a. sheet 30 of moisture-proof non-shrinkable paper having secured thereto, as by adhesive, a

strip 3| of sheet metal with opposite ends formed with marks in the form of holes 32 accurately spaced to correspond to the spacing of the flanges to be formed on the different plates.

In using the templet as a gauge to determine the locations of the flanges 24, the templet is placed successively upon the individual plates .in the same relative positions to their type-faces and then while the templet is thus positioned, the shells are marked or drilled using the holes 32 as guides. Later, these markings are used for positioning the sheets in the mechanism for forming the flanges. To enable the templet to be located properly relative to each type-face, the paper sheet 30 bears a'so-called offset proof ofone of the plates or preferably a proof taken from the original form from which such plate was made. As is well understood in the art, such an onset proof is a printed impression reading from right to left as shown in Fig. 4, so that when placed face-up upon the type-face of the corre sponding plate, the type and printed impressions will coincide. The plate thus selected for making the offset proof may be referred to as the key plate and is one for printing matter in a color which, on the composite multi c'dlor impression ordinarily furnished to the publisher with each set .of original form plates, is combined in the same area with or has a border adjoining matter printed in one or more of the other colors.

At two widely spaced points on the offset proof, the paper 30 is cut out to form apertures 33 having edges 34 which match in the composite proof with similar edges of matter printed in other 7 colors. The intersections of the edges 34 define spaced reference points corresponding to com-.

mon points on the type-faces of two or more of the plates. Thus by placing the templet upon the different type faces with the edges 34 coinciding with the type edges for printing such lines in difierent colors, the gauging holes 32 may be brought into the same position relative to the type faces of the different plates which are then marked to establish the location of the flanges 24.

The selection ofthe reference points above referred to is a. matter of choice determined by examination of the composite proof with which Formation of the templet .In describing more in detail the manner of forming the templet, it will be assumed that the plate 1 shown in Fig. 2 is to print in black color and has an area 35 forming, on the composite,

a black border around a square printed .in red by a. type area 36 on the red plate 8 (Fig. 5), the borders of the red and black areas to be in exact register. The page may also have a green area printed by areas 31 on the blue and yellow plates 9 and Ill (Fig. 6) 'and not overlapping at any point with the matter printed in black. Black might be selected as the key color, the offset proof preferably being taken from the original black plate furnished by the engraver. Longitudinal and transverse center lines 38 are then marked on the paper to determine the center of the page which is cut out to form a small aperture 39. The paper is then pasted onto the metal strip with the lines 38 at the edges of the aperture 39 matching with lines 40 scratched on the strip. Such location of the proof on the strip is size.

merely for the purpose of centering the matter to be printed on the page and since it does not concern the attainment of color register, a high degree of precision is not required. Since the green color area does not overlap the black area at any point, it is necessary, in the case assumed, to take an ofiset proof from the blue'p1ate and paste a fragmental portion 4| of the 'same onto the paper centering the same thereon in the same manner as the sheet 30.

Corners of the areas 35 and 36 might be selected as the reference points above referred to in as much as the red and black areas must register at these points. Thus the black proof is cut accurately along the inner border of the area 35 to form the edges 34 and the flaps thus formed are cut out to leave the apertures 33 of the desired Similar apertures 42 are cut out around the comers of the blue area 31 thereby defining reference points 43.

' The templet formed as above described is first placed face-up on the type-face for printing any one of the colors, for example-the red plate 8, and shifted relative to such face until the edges 34 of both apertures 33 coincide exactly with the edges 44 on the type area 36 and the reference points 45 are superimposed exactly upon the corners 46. While the templet is thus positioned, holes 41 are drilled in the marginal edge portions 48 of the sheet, the templet holes 32 being used Formation of positioning devices Preparatory to forming the flanges 24, the plates with the holes 41 drilled therein are trimmed to the shape shown in Fig. so as to locate accurately with respect to the type-face, the ends 49 of the edge portions '50 from which the flanges are formed. This is necessary for the reason that these ends 49 form the ends of the plate flanges which constitute one of the sets of positioning devices above referred to and engage with lugs 21 in locating the shell upon the backing member.

To determine the lines for such trimming, the plate is placed upon a metal sheet 5! (Fig. 9) having pins 52 entering the holes 41 and edges 53 shaped to correspond to the shape to which the plate is to be trimmed. The marginal edges 50 are then trimmed accurately to correspond to the shape of the flxture'5l, the edge portions 48 preferably being formed with tapered ends.

' -After trimming, the flanges 24 may be formed in any preferred manner but in flxed relation to the holes 41. To thisend, the plate may be supported upon a flxture or'mandrel 54 (Fig. 7) having pins 55 projecting through the holes "thereby locating the type-face definitely relative to edges 56 of the mandrel around which the edge portions 50 may be bent to form the flanges 24. This may be accomplished by dies 51 moved downwardly past the edges 56. The inturned portions 25 are formed in the subsequent movement of the dies 58 (Fig. 8) which bend the free edges of the flanges reversely onto the underside of the shell. Upon withdrawal of the pins 55, the flanged shell may be removed from the fixture in an endwise direction. Finally the edge portions 48 are trimmed off along lines 59 (Fig. 5) the plate being then ready for mounting on the press cylinder in the manner above described.

The plates for printing red, yellow and blue colors are trimmed and flanged in the same manner with the result that the flanges 24 and their ends are formed on the different plates in exactly the same positions relative to the respective type faces. Thus, in the stretching of the different shells onto the backing members, all type lines on the plates extending parallel to the axes of the cylinders will be located so as to come opposite the same lines on the impression cylinder during printing. This is due, it will be observed,

' to the uniform spacing of the flanges 24 of the different plates and their location relative to the type-faces and'also to the uniform size of the backing members which results in a uniform stretching of all of the plates of the set. Exact matching of type-lines extending in the direction of movement of the plates is produced by interengagement of the other positioning devices, that Y is, the ends of the flanges 24 and the shoulders 21. It follows therefore that if the backing mem- 'bers for the different plates are properly positioned on the press cylinders, the type-faces will, as an incident to attachment of the plates to the backing members, be positioned for the producton ofexact registration of the different colors in operation of the press.

In the use of the system above described, it will be observed that the positions of the sections l8 of the backing members need not be changed in the removal and replacement of the plates for printing different pages of the same or different issues. Once the positions of these sections on the respective cylinders has been established so that proper color registration is obtained, the sections will remain flxed more or less permanently to the cylinder. Loosening of the clamps 2B and slight shifting of the plate assembly may be necprinting in order to compensate for inaccuracies in construction. But in as much as the flanges 24 maybe positioned relative to the type-faces with machine precision according to the present' essary occasionally in preparing the press for v method, such adjustment will seldom be neces-.

combination of a plurality of type-carrying sheets for printing different colors on a page, a pair of fastening devices on each sheet extending along opposite marginal edges thereof, aplurality'of securing members attached to the respective cylinders in exactly corresponding position and each arranged to interengage with the fastening devices on any one of said plates in a fixed relation and to fasten the plate securely to the cylinder, fastening devices on each sheet being located in the same position relative to' the type-face of the sheet as the devices on the other sheets whereby a predetermined relation will be established between the different plates and the respective cylinders as an incident to'mounting the plates on the latter. I I

'2. For use in a multi-color printing press having a pluralityof cylinders rotatable in timed relation, the combination of a plurality of rectangular plates carrying type for printing in different basic colors, fastening devices formed along two opposite marginal edges of each of said plates in the same space relation to the type-faces of the respective plates, means 'on the respective cylinders engageable with saiddevices and operable to stretch the plates over the surfaces of the respective cylinders circumferentially of the latter, said means being prearranged in corresponding predetermined positions on the different cylinders whereby to produce exact register of type edges extending circumferentially of the cylinders, and means on the cylinders engageable with respective plates and acting during stretching thereof to locate the plates longitudinally of the cylinders in positions such as to establish color register of type lines extending circumferen'tially of the cylinders.

3. For use in a multi-color printing press having a plurality of cylinders, the combination of i produce exact color register during printing.

4. For use in a multi-color printing press having a plurality of cylinders for respectively supporting the type for printing the different colors, a plurality of plates carrying type for printing the different colors and each having devices thereon by which each plate may be secured to one of said cylinders, the positional relationship between the devices on each plate and the typeface thereof being the same as in each of the other plates, and cooperating securing devices on f said plates, said cooperating devices being attached to therespective cylinders in corresponding positions whereby the type-faces of the different plates will be positioned for the attainment of color register as an incident to the attachment of the plates to the respective cylinders, and said cooperating devices being mounted upon the respective press cylinders for adjustment in unison in two transverse directions whereby to permit the plates to be shifted varying distances laterally of the cylinder surfaces.

5. Ina multi-color printing press having a plurality of cylinders for respectively supporting the type for printing the different colors, a plurality of plates for printing the different colors each comprising a type-carrying sheet and a backing section, interengaging devices on the margins of .each sheet and its backing section arranged to engage in a positional relationship such as to locate a common reference point on the different type surfaces accurately with respect to a point common to all of said plate sections, and means on the respective cylinders clamping the respective backing sections against the cylinder surfaces in accurately corresponding positions while permitting of edgewise adjustment of each plate along the surface of its supporting cylinder whereby the type faces of the difierent plates will be positioned for attainment of color register during printing as an incident to attachment of said sheets to their respective backing sections.

.ARTHUR B. DAVIS.

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