US760235A - Process of evening the faces of stereotype or electrotype plates to render them capable of producing uniform impressions. - Google Patents

Description

M. A. MUKEB.

PATENTED MAY 1'7, 1904.

PROCESS OP EVENING THE FACES 0F STEREOTY'PE 0R ELECTROTYPE PLATES TO RENDEB. THEM GAPABLE 0F PRODUGING UNIFORM IMPRESSIONS.

APPLIOATION FILED MAB. 1a. 1904.

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2 SHEETS--BHEET 1.

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PATENTND MAY 17, 1904.

2 SHEETS-SHEET 2.

M. A. MQKEE. PRocBss 0F EVENING THE PAGES 0F STBNBOTYPB 0R ELEGTNOTYPE PLATES APPLIOATION FILED MAB., 18, 1904.

T0 RENDER THEM CAPABLE 0F PRODUGING UNIFORM IMPRESSIO'NS.

No MODEL.

flag?? UNITED STATES Patented May 1*?, 1904.

PATENT OEETCE.

MILTON A. MCKEE, OF NEW YORK, N. Y., ASSIGNOR TO C. B. COTTRELL & SONS COMPANY, OF NEW YORK, N. Y., A CORPORATION OF NEW JERSEY.

PROCESS F EVENING THE FACES 0F STEREOTYPE OR ELECTROTYPE PLATES TO RENDER THEM CAPABLE OF PRODUCING UNIFORM IMPRESSIONS.

SPECIFICATION forming part of Letters Patent N0. 760,235, dated May 17, 1904:.`

Application led March 18, 1904.

To all 'LU/w11?. it may' cm1/cern:

Be it known that I, MILTON A. MCKEE, a citizen of the United States, and a resident of the borough of Manhattan, in the city.and State of New York, have invented a new and useful Process of Evening the Faces of Stereotype and Elcctrotype Plates "to Render Them Capable of Producing Uniform impressions, of which the following is a specification.

Stereotype and electrotype plates of type matter, aswell as those containing pictorial illustrations, in the condition in which they are ordinarily delivered by the manufacturer to the printer are generally or very often more or less defective in that their faces are so uneven that the printed impressions which they produce have some parts unnecessarily dark or heavy, while other parts are objcctionably light or pale. These defects are known in the trade as sinks or shrinks In such defective plates the parts which produce the darker or heavier impression are commonly thicker than the parts which produce the lighter or paler impression, the backs of the plates being even or plane, or nearly so. and the sinks or shrinks being only or chiefly on thc face.

The object of the present invention is to vcure these defects, and to this end the said invention is performed in the following manner: There is first obtained, by laying together one upon another two or more sheets or layers of paper or like fabric, a matrix the face of which corresponds exactly or approximately with the face of the plate to be treated, its higher or less sunken portions corresponding with the higher or more prominent portions of the face of the plate and its lower or more sunken i portions corresponding with the lower or less prominent portions of the face of the plate. The matrix thus obtained and the plate to be treatedare then placed face to face with the more prominent parts of the two opposite each other and the less prominent parts of the two opposite each other and While they are so placed together are laid on the bed of a shaving-machine with the matrix in register with Serial No. 198,864. (No model.)

the face of the plate, the back of the plate being upward, and while they are so laid the `back of the plate issubjected to a shaving operation in which by the plowing nature or pressure of the shaving-knife when removing the shave of metal from the back of thc plate every part of the face of the plate through the yielding 4 moved by the act of the shaving operation than at such parts on the back of the plate where the plate sprung down into the less or low parts of the matrix. The shaves may consist of a single cut or of two or more light successive cuts. After the shaving operation and f its being relieved from the shaving pressure the plate bylits own resiliency springs back so far toward its original condition that its face resumes its original form containing its original sinks or shrinks, while its back so nearly corresponds with its face that the thick ness of the plate measured to the face of the type matter is uniform in all parts. The plate `thus reduced to uniform thickness is then placed without the matrix between two perfectly parallel smooth surfaces, such as those of the bed and follower of a heating' box or press, which are heated to a suitable degree of temperature to so soften its metal as to render it suliiciently liexible, and is there subjected to such pressure as to render it perfectly even both on its face and back, in which condition it will remain after cooling, when it is ready for printing.

The invention is illustrated in the accompanying drawings, in which- Figure 1 is a face View of a printed sheet obtained from a defective plate, showing the lighter and darker impressions in different parts of the imprint. Fig. 2 is a transverse section of the defective plate, which gives such an imprint as is shown in Fig. 1; Fig. 3, a

vtransverse section of a matrix, consisting of sheets or layers of paper placed together; Fig. 4, a transverse sectional view of the plate and matrix laid together face to face preparatory to shaving. Fig. 5 represesents in transverse section the matrix and plate face to face between the bed and knife of a shaving-machine, showing the plate pressed by the knife against the higher parts of the matrix and as having shavings taken from its thicker parts. Fig. 6 represents the section of the plate after the shaving operation, but before the fiattening which constitutes the finishing operation; Fig. 7, a sectional view of the plate alone and of the flat bed and follower of a heating box or press between which the plate is flattened; Fig. 8, a section of the finished plate.

In Figs. l and Q the too-'heavy parts of the imprint and the higher'parts of the face of the plate 10 which produce it are both designated by the reference-numerals 11, and the too-light parts of the imprint and the lower parts of the face of the plate which produce them are designated by the numerals 12. The parts ofn the face of the matrix which correspond with those of the plate are designated by similar numerals. The layers of which the matrix is composed are preferably made from'proofs taken on thin paper from the defective plate, using one of said proofs 13 as a base and first building up by pasting on a layer or layers consisting of the dark portion or portions cut out from one or more ofother such proofs and afterward overlaying and pasting over the whole with one or -more of other such proofs `from which the lighter parts have been cut out and thrown aside, the number of said layers of each kind, one or more, depending on the degrees of unevenness of impression produced by the dierent parts of the defective plate. The example which I have selected for illustration, (given in Figs. 3, 4, and 5,) consists of only one layer of each kind, that affording better facility for clear representation, the layer next the base consisting' of two pieces 14 cut from one proof-sheet and corresponding with the dark portions 11 on the representation, Fig. 1, of the proofsheet, and the upper layer being formed from another proofsheet 15, from which the light parts (indicated by 12 in Fig. 1) have been cut out, there being three layers in all. When the matrix thus obtained and. the plate to be treated are registered face to face, as shown in Fig. 4, and so placed together in the shaving-machine between the bed 16 and the knife 17 thereof and run through said machine, the plowing and pressing action of the knife on the back of the plate causes the plate to bend in conformity to the cut-out or lower parts of the face of the matrix, forcing the less prominent parts of the face of the plate into the less prominent parts of the face of the matrix, and thereby reducing the want of prominence in those parts of the face of theplate, while the parts of the plate in which the face has greater prominence are held up by the higher parts of the face of the matrix and prominences Y are thereby produced on the back of the plate.

The knife being perfectly adjusted relatively to the bed of the machine only takes off in shavings 18, as shown in Fig. 5, enough of those'prominences on the back to 'reduce those parts of the plate which contain them to the same thickness as the other parts; but though thus reduced to uniform thickness the plate after its release from the pressure of the shaving-knife is caused by the resiliency of its metal to spring back so far toward its original condition that its face resumes its original form, as illustrated `by Fig. 6, in' which it will be seen that although the plate is of uniform thickness it isin a more or less wavy condition. That condition is corrected by the final stage of the process, which consists in the pressure between the two heated smooth flat parallel surfaces 19 20, Fig. 7, which bringsl the lplate in all parts, both its printing-surface and its back, to a level condition for perfect and uniform printing and renders unnecessary any form of underlay under the n plate or overlay on the impression-surface of the cylinder.

I have only thought it necessary to illustrate and describe my invention in detail as applied to flat plates; but it will be obvious to those skilled in the art that it may be adapted to the evening or taking out of the sinks or shrinks from curved plates, all that is required for such adaptation beingV to substitute for -the beds, matrix, and follower of flat form represented beds, matrix, and follower having curvatures corresponding with those of the plate and to substitute for the shaving-knife represented a knife having a movement conforming to the latter curvatures.

What I claim as my invention iS- 1. In a process of treating uneven printingplates for evening their faces, the improvement which consists in subjecting the plate to a shaving operation while its face is in contact with a matrix having in its face more and less prominent parts corresponding with the more and less prominent parts of the face of the plate. M Y

2. In a process of treating uneven printingplates for levening their faces, the improvement which consists in preparing from a printed proof of the plate a matrix with more and less prominent parts corresponding with the moreV and less prominent parts of the face of the plate and subjecting the plate to a shaving operation with its face in contact with the face of said matrix. f

3. In a process of treating uneven printingplates for evening their faces, the improvement which consists in placing the plate with IOO IIO

its face in contact with a matrix in which are more and less prominent parts corresponding with the more and less prominent parts ofthe face of the plate and While in such contact subjecting the plate while it is resting against and registered to the face of the matrix to a shaving operation on its back.

4. 1n a process of treating uneven printingplates for evening their faces, the improvement which consists in placing' the plate with its face in contact with a matrix in which are `more and less prominent parts corresponding with the more and less prominent parts of the face of the plate and While in such contact subjecting the back of the plate to the action of a shaving-knife which at the same time forces the face of the plate to form the counterpart of the matrix and also shaves the back of the plate.

5. The process of treating uneven printingplates for evening their faces which consists in placing the plate with its face in contact with a matrix in which are more and less prominent parts corresponding' with the more and less prominent parts of the face of the plate, then While inn such contact subjecting the plate at the same time to pressure against the matrix by the act of a shaving operation on its back, and afterward without the said matrix subjecting the plate to pressure between two parallel surfaces.

6. The process of treating uneven printingplates for removing sinks or shrinks from their faces, which consists in placing the plate with its face in contact with a matrix in which are more and less prominent parts corresponding with the more and less prominent parts of the face of the plate, then while in such contact subjecting the face of the plate at the same time to a pressure against the matrix by an act of shaving metal from its back, and afterward subjecting the plate Without the matrix to pressure and heat between two parallel surfaces, said process producinga plate of uniform thickness with even face and back.

In testimony that I claim the foregoing as my invention I have signed my name, in presence of two witnesses, this 17 th day of March,

MILTON A. MCKEE. Witnesses:

FREDK. HAYNES, HENRY THIERNE.

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