US1639171A - Printing plate and method of production thereof - Google Patents

Description

Aug. 16, 1927.

' F. FISCHER PRINTING PLATE AND METHOD OF PRODUCTION THEREOF Filed MarchlO, 1926' omo eooooooooooo voooooooooooxowo Patented Aug. 16, 1927.

' UNITED STATES PATENT 0 FERDINAND rrscnnn, or. nnnnnv, GERMANY.

1,639,171 FFICEJ)" rnr'urme PLATE AND METHOD-or rnonocrrou rnnnnon- Application filed March 10, 1926. Serial No. 93,758.

As printing plates for socalled ofiice duplicators there are mostly used paper plates.

with a coating of wax orsimilar material. The use of such plates however entails a enumber of disadvantages.

For this reason some oflice duplicators have previously been produced which operate with more suitable printing plates of metal or metallizedor metal-coated paper. These printing plates are so thin that they can be typed upon in an ordinary typewriter just as an ordinary sheet of paper, whereupon printing is effected by means of the printing'plate in the usual planographic or T5" lithographic .method, for example offset process. M

Such metal printing plates have extraordinarily great advantages but some disadvantages wer'e hitherto unavoidable.

If simply the raw metal plate is supplied to the purchaser as the printing plate, the

purchasenin order to be able to operate ng plate to a larger scale.-

with-the plate,'mus t himself treat the print-' in-g surface in the manner well known in. the art of lithography. This includes grain --ing the printing surface and etching before printing, which imparts to. that part of the printing surface, not provided wlth inscriptions, images orlines for printing, the capacity of rejecting printing ink when in a damp condition. I r

The production of good and -uniform graining, however, is a" very-diflicult operation on thin sheet material so that an in sufficiently skilled purchaser or user will spoil a great many plates.

In order to remedy this disadvantage it has already been suggested to supply to the purchaser from the factory completely prepared plates, that is grained and etched printing plates, which consequently when in a damp condition reject printing ink over their entiresurface. This however has the disadvantage that the typing or marking of the written matter causes consid *bl' ditfipecially prepared carbon papers, heat treatment and thelike. y

The invention eliminates all these difliculties, in that it suggests a novel middle course. .Accordi ng to the invention the purchaser or user is supplied with the finished grained printing plate, which however has not been etched, as a new article of manufacture. The purchaser need not therefore be troubled with the difficult process of graining or roughening and is therefore not liable to spoil the plate in carrying out this operation.

On the other hand he can type upon the half finished plate as on an ordinary sheet of paper, in. a typewriter and then without any up to about 21 cm. wide and 33 cm. in length.

In the accompanying drawings there is diagrammatically illustrated one constructional example of the invention and a particularly advantageous method of production. The invention however is not limited in any way thereto.

Fig. 1 is a plan of a printing plate according to theinvention on a reduced scale.

Fig. 2 is a section of a part of the print p The printing plate a is along its two nar row sides provided with a plurality of holes 6 for the purpose of attachment to suitable pins of the cylinder ofan oflice duplicator, and preferably consists of an extremely thin plate of a metal suitable for lithogfiaphic purposes such as zinc or aluminum, for example only about 0.05 to 0.06 mm. thick. For the urp'ose of more convenient manipulation t with a-sheet o of rial.

According to theinvention the consumer is supplied-with the sheet cut to a useful size and provided with holes I) insuch acondition that theprinting surface is already provided with the graining oi, which for the "sake -of clearness is shown by a thick line. The production of this graining of the ready out small sheets a would be efitremely diflicult inpractice. course is had, according to the invention, to special treatment as represented in Figs. 3 and 4, according to which a plurality of printing plates are grained in the form of a large combined sheet or band and then cut into the separate rintingplates.

According toig'. 3 aflar'ge plate 9 is clamped in a suitable manner on a rotary cylinder 1'', whose surface corresponds to is plate is coated on the rear side'- paper or the like soft mate- For this reason rethat of a plurality of printing plates 41. Against the surface of the sheet 9 is projected a sand blast h, for example by means of projecting wheel i, whereby the surface [S grained. The sheet 1 is then cut into i small plates 0.

scribed in connection with Fig. 3, whereupon the band is wound upon to the roller 15 p, in order to be then cut into plates a.

. What I claim and desire to secure by Letters Patent of the United States is As a new article of manufacture, a small printing plate suitable for lithography comprising a metallic sheet provided with a commercially grained printing surface, and of uniform thinness throughout to both end edges thereof, said sheet being of such thinness as to be successfully tensioned on the cylinder of a duplicating machine by more pins and holes, the end of said sheet being provided with a series of holes for this purpose extending transversely there across.

In testimony whereof I affix-my si nature.

FERDINAND FISC ER.

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