US840775A - Process of stereotyping. - Google Patents

Description

been employed.

Up to the present time the casting of stere-' UNITED STATES P T NT, orFIoE,

SIGVALD ALFRED CHRISTIAN KRISTENSEN; or soToRP PERVALBY, NEAR COPENHAGEN, DENMARK, ASSIGNOR 1T0 ANDELSSELSKABET 1NTER NATIONALT METALLOTYPIKOMPAGNI, LIMITED, or COPENHAGEN,

DENMARK."

enema-75.-

PROCESS OF STEREOTYPING- Patented Jan. 8, 1907,

Application filed July 27, 1905. Serial No. 271,537.

.Toall whom it may concern:

\ Be it known that I, SIGVALD ALFRED Cnnis- TIAN,.KRIsTENsEN, stereotyper, a subject of theKing Valby', near Copenhagen, Denmark, have invented a certain new and useful Process of stereotyping, of which the following is a specification.

This invention relates to theproduction of matrices for the stereotypin of type-forms, line-etchings, and half-tone b ocks or the like; and it has for its main purpose to increase the clearness and sharpness of the matrices and their durability and make them better adapted than are the matrices heretofore used to resist the action of several castings, even. at 'gher temperatures than have heretofore otype-plates in ordinary paper matrices has been made at temperatures ranging from 280 to 340 Fahrenheit, as the common paper matrices are not able toresist higher temperatures. Alloysofsuchlowmelting-points suffer, however, from the defect of being rather soft, a circumstance-making it necessary very often to givethe stereotype-plates an aftertreatment-nickel and copper plating them, for instance-em order to increase the hardness of their surface, and thus enable them to betterresist the pressure and wear caused by. the printing; ut even when employing such rather low temperatures of cast-' mg the ordinary paper'matrices cannot be used'for more than a very few castings, (in the reproduction of type-fo'rms perhaps two or three,) the'reason being that the repeated application of molten metal to the paper ma trix makes its surface brittle and urned. This drawback is especially rorninent'in the casting of stereotype-plates or rotarypresses, because the amount ofmetal used, andconsequently also the quantity of heat contained in such metal, is here very considerable. Ordinary paper matrices are, besldes, not very suitable for the stereotyping of fine-line etchings, and they are especially unfit forlstereotyping autotype's or so-called half-tone of Denmark, residing at Sotorp per ,tionsubsequently cast therein will therefore 'be lacking in accuracy and depth, so that the intagli-o cavities between the grains or lines may blacken the prints produced from the stereotype-plate. Ordinary paper matrices 'suffenfinally from the defect that they will not at all slip the stereotype-plate founded therein unless they are previously rubbed by,

graphite, powdered soapstone, or the like, which treatment will of course be detrimental to their sharpness. v w

. The present invention has for its purpose to produce matrices with such a coating on their surface that the matrix is on that account'enabled '(1) to endure a considerable number of castings; (2) to resist a temperature of casting considerably higher than what has been used heretofore, so that alloys of.

"greater hardness may be employed; to withstand bending without any dangerof breaks or cracks in the surface, (4) to take very accurate impressions of the veryvfinest as well as of the coarsest cavities and projections, (5) to be used as a mold without any 7 kind of aftertreatment, such as powdering,

greasing, &c.

The solution of the special problem embodied in requirement No. 4 1n theabove enumeration-namely, on an ordinary paper:

matrix suitable for stereotyping of typeforms to produce also the very finest impresv sions has been attempted by giving those parts of the mixed form (types and half-tone looks) that havethe fine cavitiesvi z the half-tone blocks a coating consist i of whiting or powdered clay, mixed, if des red, with water, which coating is then by wiping removed from the printing-face beforethe resse'd down into ordinary paper flong is laid on and then parts ofth'e form coated with clay or the like the impression is, produced b means of the fine-grained substance that fil s the fine cavi-' ties of the form and when the wet paper flong is laid on under pressure adheres to the flong and stands out from its surface after it is removed from the form. Even admitting that an impression of the fine relief of the form may be made in this manner, it is nevertheless notdeep or sharp enough to give a faultioo less reproduction of the original in such a matrix. This drawback is due partly to the fact that the substances used will shrink considerably during the subsequent drying, and

consequently be subject to the formation of fissures and crevices, and partly to the circumstance that the air lodged in the cavities of the autotype cannot escape when a paste such as the one above described is a plied to the autoty e, and consequently wil prevent the paste om penetrating to the very bottom of the cavities and from .closely followingtheir sides. For thesereasons the relief becomes inaccurate and 'full of fissures and also too'low. Printinglates cast in such a matrix will-therefore be liable to blacken the prints-taken therefrom-and generally will not iveas sharp and clean prints as the original.

he matrices produced in the above-'described manner-will further suffer from other defects and drawbacks, some of which are to 1 be mentioned in the following: The impression-surface is very easily fractured, because chalk, clay, and the like are brittle substances,.-the grains of which are liable to "break when the matrix is bent, or even when it is removed from the form after drying. Besides, it is liable to be damaged if touched. These substances are also porous, and durin their drying fissures have arisen. They will therefore not easily-slip the cast metal, and as they are b'rittle it happens often that the grains break ofi-when the matrix'is removed and remain in the cavities of the original etching. Thisis unfortunate, partly on account of the damage to the matrix and partly because the etching has to be carefully cleaned before itcan be used again.

the adhering chalk, .&c., can only be dissolved by usmg acids, and the latter will also very ra idly attack the etching itself, espe-' ciall y'i' it is 'a zinc etching, and very likely I come brittle and burned-when the metal is cast therein and will endure only a very few castings, even at low temperatures.

Accordin to the present invention the entire face of the matrix is coated with a metallic film, endowing it with all the desirable qualities enumerated before under headings -1-5, and the substances as wellas the process employed for this purpose insure that the matrix thus obtainedjwill'become anexact negative copy of the relief of the form'. 4 f

"The substance to be applied to the form consists, according to the present invention, of a li uid mixture'offinely powdered orpulverize metal. 'Such mixture may be formed of about ten per cent. of borax in water, to

which is addedenough ungreased-casein to This cleanin is'exceedinglydifficult and can,-in' fact, on y be, made by-chemical means; but

brin the mass to a pulpy condition, after whic a volatile medium, such as alcohol, is addedto bring the mass to a liquid state. A sufficient quantity of the powdered metal may then be added.

Especially aluminium powder is eminently suitable as a metal for the pur ose mentioned, partly because it is easi y held in suspension in the proper amount of liquid and partly because it may in contrast to the substances heretofore used easily and quickly be dissolved by a weak solution of sodium hydrate, which practically will not attack the zinc, so that even if by inadvertence a part of the'metallic skin might remain in and on a zinc etching the latter could be easily washed freelfofsuch remnants without damage to itse The method of producing such a matrix thisis placed, in the usual way, the damp paper flong, and the Whole thing is then treated in the matrix-press according to the ordinary method used in the so-called hot stereotyping. The metallic film on the form is thus transferred to the surface of the matrix, so that when the matrix is removed from the form the film too leaves the form and adheres to the matrix, formin on its face a continuous metallic film or sun presenting an exceedingly fine and accurate negative repro-.

duction of the form.

The great and general superiority of this process over the methods formerly employed lsmainly due to the employment of a metallic powder as the filling mass. The reason is that in drying this will not shrink appreciably, and in consequence the im rint on the matrix will be just as sharp an deep as the relief of the form itself. film on account of being both hard and still somewhat elastic is also highly tenacious, both against. bending of the matrix and against casual handling and wear. It is, further, proof against even much higher temperatures than those used in stereotyping and has a high heat-conducting power. By this cirv cumstance is attained the advantage of being able to use in the casting alloys of higher melting-point, and therefore greater hardness,

than those usually em loyed, whereby the necessity of subsequent y hardening the face of the stereoty e-plate, as described before. is

avoided, an besides, the heat in the metal The metallic and in consequence the metal oured out on the metallic skin will after so idifying veryeasily slip the matrix, there being no necessity for, greasing the latter, whereby its sharpness would be diminished before making the casting. Another Jvery essential feature of the invention is the employment of the substance in a liquid state,whereby themetal powder is allowed to settle, so as to form a: solid film ,closely following the finest cavities of the autot pe.

In the'clabms I have used the term printing-form to include all kinds of type matter, galvanoes, etchings, half-tone etchings, and the like, the invention being perha s of greatest importance in connection wit half-tone etchings. c

Having now particularly described and ascertaincd the nature of my said invention and in what manner the same is to be performed, I declare that what I do claim is 1. The process for making matrices for a stereotype from a lprinting-form, which con-' sists in coating suc form with a volatile fluid containing an adhesive substance and a metallic powder, and after drying forming a matrix or flong of paper or papier-mach thereon, said coating being transferred to the said matrix and forming when the matrix is dried a continuous and tough metallic film or skin extending over the face thereof.

2. In the making'of matrices for a stereo-.

type wherein a flong of fibrous material is pressed onto the printing-form, the process which consists in coating one of said devices with a liquid containing a fine metallic pow-.

der, and then pressing the flong and form together to formthe matrix, such coatin con stituting a part of the matrix when the atter is removed, and forming a metallic skin extending over the face thereof.-

3. In the making of matrices for a stereotype wherein a flong of fibrous material is pressed onto the printing-form, the process which consists in coating one of said devices with a liquid containing'a fine aluminium powder, and then'pressing the fiongand form together -to form the matrix, such coating constituting a part of the matrix when the latter is removed, and forming a metallic film or skin extending over the face thereof.

4. A paper or papier-mach matrix for stereotyping a printing-form, having on its face a dry and solid film consisting of a metallic owder with an adhesive as a carrier.

n witness whereof I have hereunto set my hand in presence of two witnesses.

SIGVALD ALFRED CHRISTIAN KRISTENSEN.

Witnesses JULIUS SELEMANN, ALBERT G. MICHELSEN.