US1375874A - Manufacture of printing-plates or surfaces for printing from - Google Patents

Description

A.]. N. WALKER MANUFACTUR E 0F PRINTING PLATES 0R SURFACES FOR PRINTING FROM.

APPLICATION FILED JAN-251198n Patented Apr. 26, 1921 3 SHEETS-SHEET I.

A. J. N. WALKER.

MANUFACTURE OF PRINTING PLATES 0R SURFACES FOR PRINTING'FROM.

APPLICATION FILED 1AN.25.I918.

Patented Apr. 26, 1921.

3 SHEETS-SHEET 2.

\lllll Ill A. J. N. WALKER.

MANUFACTURE OF PRINTING PLATES OR SURFACES FOR PRINTING FROM. APPLICATION FILED JAN, 25, 1918.

1,375,874. Patented Apr. 26,1921.

SHEETS ALFRED JAMES NEILL WALKER, OF LIVERPOOL, ENGLAND.

MANUFACTURE OF PRINTING-PLATES 0R SURFACES FOR PRINTING FROM.

Application filed January 25, 1918.

1 o all to 7mm it may concern Be it known that I, ALFRED JAMES NEILL WALKER, a subject of the King of Great Britain, residing at Liverpool, inthe county of Lancaster and Kingdom of England, have invented certain new and useful Improvements in or Relating to the Manufacture of Printing-Plates or Surfaces for Printing From, of which the following is a specification.

This invention has reference to certain improvements in making printing plates from celluloid, or other similar material that can be softened by heat.

One of the difficulties experienced in the molding of warm celluloid and like sheet material lies in the fact that gas or liquid emanates from the material during the process, and being trapped with perhaps some air as well, between the pressing members so that it cannot escape, it causes stria tions or bubbles to be formed on the face of the product.

Heretofore in one method of molding warm celluloid sheet material, fluid pressure has been employed in direct contact with the surface to be modeled thereby. This method involves practical inconveniences and moreover gives less satisfactory results than does the process of the present invention. In another method rigid press plates operated at a high pressure were employed and the space between them containing the celluloid and the mold was made air tight by a rubber packing. This space was put in communication with a vacuum so as to withdraw any air during the pressing process, and the mechanism was therefore somewhat complex. In yet another method the celluloid was subjected to pressure between two faces one of which was rigid or hard and the other of which was an air pressure bag freely deformable by the surface (6. 9. that of a photographic carbon negative) against which it acted, the characteristic feature being the employment of a pressure sufficiently low to permit such gas or liquid as comes out of the celluloidor the like to escape laterally between any of the said surfaces and issue at their edges into a r gion of still lower pressure. In other arrangements the space between the two faces (containing the celluloid) one of which was rigid and hard and the otherwas an air or water bag, was made tight or the best pos sible fit, and no means whatever were pro- Specification of Letters Patent.

Patented Apr. 26, 1921.

Serial No. 213,788.

vided for withdrawing the gas or liquid which emanates from warm celluloid.

though in one instance it was proposed (in allowing high pressure to be employed so as to produce a celluloid plate which will take the place of the ordinary electroplate or stereotype for printing letter press, pictures, posters, paper hangings and so on, will allow the gas or liquid that emanates from the warm celluloid to escape. By celluloid I mean not only celluloid itself, but any material which is similar to celluloid in that when warmed and pressed it exudes gas and liquid.

My method consists in forming a matrix laying the same on the hollow table of a press, providing in connection with the follower. of the press a recess in its face to which an inflatable mattressis applied, laying on the matrix a sheet of celluloid or the like, then bringing the inflatable mattress face of the follower toward the table so that while the mattress will lie against the sheet which slightly enters into the recess in the follower the rigid margins of the table and follower will be spaced apart or leave clear passages between them to allow any or liquid coming out of the sheet to escape, admitting hot fluid under pressure into the hollow chamber in the press table to warm the matrix and soften the sheet, inflating the mattress with air under pressure to press the sheet into the matrix and finally releasing the pressure and chargingthe chamber with cooling fluid to harden the sheet. By this method the mattress will. impact against the sheet while the rigid margins of the table and follower will be spaced apart or leave clear passages between them to allow such gas or liquid as comes out of the sheet to escape laterally through the passages between the table and V follower, and also any air between the mattrees and sheet will be urinen of" therethrough when the nr l am however aware that prior to this invention been prov hollow chambers which re ch hot fluid to i sequently wits a cooling;- T

The matrix itself is produced in the iollowing manner. The type, engraved plate or other surface to be printed from is so n ill) by the compositor in the usual way, and a. thin sheet or lead, vul anite, or iiber is im pressed upon the face of the term so as to produce a matrix. This is etl'ected by a matrix roll' machine, mangle or p wherein the form is brought into contact with the sheet of lead or other material and is impressed thereinto, so that an exact facsimile or the printing surface (set up by the compositor) is produced and forms the inatrn This ma '1; cons n a mold the printing plate is made.

In order that my invention and the manner of pertorining:- the same may be prope understood and the improvements as co 1- pared with known apparatus may be diilerentiated T will now describe the manner of carrying my invention ct erence being had to the appenc :l ings, in which 19' ;u l is vertical cross section of the press, Fin. 2 thereof, and 3 is anenlarged vertical sectional view talrni th l the follower, showi ,he tering the recess in the tolloweix In these drawings it is the table or bed of the press and B the head, platen or follower, which is operated mechanically from the crank shaft 0 so that the heat can be brought toward the table A by turning the hand wheel D the latter operating the cranlr shaft through the gear wheels E and F.

The table A is provided with a recess with inclosing sides to receive the ma G, and the head or follower B of the press is either recessed to receive the inflatable szclr or mattress or the equivalent rrangement may be provided namely providing the follower with a recess to the margin oi? which an india rubber diaph agm is attached so as to term a mattress The table or bad it or the press has a hollow chamber 1 in it into which steam can be injected through the pipe J for heating the matrix Si or into which cold air or other fluid can be driven through the pipe 1 for cooling. This cha1nher I is also provided with a steam safety valve L which will automatically open to permit steam to escape should the pressure exceed a given limit. A release or exhaust valve M for steam is also provided. An air pressure pipe N from the air pump passes into the head B of the press to the can is provided also with an air pressure release valve and the press is provideo with air pressure, steam pressure, and safety valve air pressure gages P Q, and

In operation the matrix Sr is laid in the recess in the table A, the sheet 01 celluloid S or other analogous material is applied, and the steam through the pipe J is now turned on so as to heat the matrix Gr and the celluloid sheet laid thereon. The inflatable mattress iace of the follower is brought toward the table so that the mattress H will lie against the sheet S which enters slightly into the recess in the follower so that the s oi? the recess lie closely all around the celluloid sheet thus holding the celluloid sheet in position, and yet allow of any air or any gas or liquid between the celluloid sheet and the matrix to escape laterally at the edges of the sheet because there is no tight clamping olf the inflatable mattress tace of the press against the table, there being in fact a clear open space T between the eration and pumps air through pipe N into the mattress H and compresses it therein and pressure is maintained in the mattress for just so long as it is necessary to cause the surtace of the celluloid sheet to be molded on the matrix. The air pump is now stopped and the steam shut oil, and cooling fluid is injected into the table or base A or the press through the pipe K so as to cool the matrii and harden the sheet. The head B and table A of the press are separated and the molded sheet of celluloid is taken out and (when mounted on a block to make it type high) is used as a surface for printing from in the operation described the rubber face of the mattress presses the celluloid sheet on to the matrix by which a replica oi the matrix is produced in relief or int-apglio on the celluloid sheet. The celluloid is forced into all the interstices or depressions in tile matrix i is molded in such manner to produce a plate without striations or bubbles lfor printing letter-press, pictures, posters, paper hangings and so on.

My improved printing plates can of course be m de ilat in which. case a dot matrizt is used to mold them, r they can be made of curvilinear shape as required for ro- V laid upon the matrix will partially enter the 1917, in the presence of two subscribing witrecess below the mattress while permitting nesses.

the gas or liquid between the sheet and the ALFRED JAMES "BILL WALKER matrix to escape through the space between 5 the table and the follower. Witnesses:

In Witness whereof, I have hereunto G. C. DYMOND,

signed my name this 21st day of December JOHN MCLAOHLAN.

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