US1768729A - Automatic engraving - Google Patents

Description

July 11930. N. s. -AMsTuTz 1,768,729

AUTOMATIC ENGRAVING Filed Ju1y'28, 1928 Ura/13e l Patented July ll, 1930 l I,

UNITEDy STATES PATENT oFF-lcs NOAH S. AMSTUTZ, OF VALPARAISO, INDIANA AUTOMATIC ENGRAVING Application filed July 28, 1928. Serial No. 296,075.

My invention relates to improvements in relation of relief, lines per inch and angle of automatic engraving and it more especially graver. consists o f the features pointed out inthe an- Fig. 9 is also a diagrammatic view shownexed claims. ing a dry-mat impression under rollingl pres- The purpose of my invention is to provide sure.

a process and means for automatically pro- Fig. 10 isadiagram ofa mat being cast ducing engraving for surface or intaglio with type metal in stereotyping.

- printing without the intervention of so-called In a general sense the engraving technique half-tone screens; that employs for relief described in the Patent No. 569,595, granted '10 printing purposes a negative carbon relief on Oct. 13, 1896, and the patent issued on 60 photograph; that utilizes a positive carbon N0v.24,1903, bearing number 744,852 is used relief photograph for the ultimate producin producing the engravings described herel tion of intaglio prints; that additionally vemin. One of the outstanding shortcomings of ploys a reversal step in changing an ordinary the process and method disclosed in these patkodak film from' a negative to a positive for ents is the fact that hitherto it has been im- 65 use in producing a carbon relief photographpossible to use film engravings 10 formed on ic negative and from this an engraved film celluloid for printing purposes with hot for direct relief printing; that maintains a stereotyping which has been universally in close mathematical relation between the invogue. The reason for this difficulty is found cluded V angle of the graving tool, the mazlzi in the fact lthat the wet papier-mch flong 70 mum relief of the photograph and the coopafter being beaten into the form was heated erating lines per inch of the engraved result; to dry it while in situ, thus destroying the and that makes use of a cold dry-mat dupl- Celluloid film. To first electrotype the ilm eating step for stereotyping the engraved reinvolved inadmissable delays. Now as the sult and subsequently printing it on soft dry-mat stereotype 15 has come into practical 75 paper by rapid rotary presses. use it is possible to simply place an engraved With these and other ends in view I illus- Celluloid film 10 onto a suitable base 16 which trate in the accompanying drawing such inwiththe thickness ofthe lm is not more than stances of adaptation as will disclose the type-high (.918) and lock it in the form broad underlying features of my invention with linotype slugs, display-type, etc. .80 without limiting myself to the specific details Another difficulty encountered .heretofore shown thereon and described herein. in producing such films for relief printingv Figure 1 is a diagram of an ordinary negahas been the necessity of changing an orditive. nary negative 1 into a lantern-slide trans- Fig. 2 isl a diagram of the first stage of a parency or positive and using this for pro- 85 reversal of Fig. l. ducing a carbon relief negative 8 to be the Fig. 3 is also a diagram of the second stage original from which the engraved lm 10 or complete reversal of Fi 1. 1 v is made. This involved considerable time Fig. 4 is a diagram o? a positive being which is now obviated through the use of a printed onto a paper supported carbon tissue. negative reversal step (Figa 1 to 3 inclusive) 90 Fig. 5 is a similar'diagram to Fig. 4. The similar to that employed in natural coloi` positive however being jointed onto a carbon photography and the use of dry-mat stereocoating on a transparent base. typing. In this way a new result-the final Fig. 6 shows a diagrammatic represcntaprinting stereotypes 18 are secured. tion'of a carbon 'relief print secured by the In practicing my invention, may use such 95 means shown in Figures 4 or 5. u alternative expedients and equivalents as the Fig. 7 is an enlarged diagram ofan lenexigencies of varying'conditions may degraved film superposed on a carbon relief mand, without departing from the broad photo. spirit of the invention. i Fig. 8 isa detached'diagram showing the The successive'steps from the beginning 10l to the end are outlined in the following description. An ordinary kodak or other negative 1, Fig. 1, is developed at 2 in any well known manner by metol-quinol, rodinal, ete. At the conclusion of the development the film or plateis rinsed for about twenty seconds and is then placed in any suitable reversing bath, such for instance, as

Permanganate of potassium--- 2 grams 31 grains Sulphuric acid 0 ccs. 170 minime Distilled water to -1000 ccs. 35 oz.

After leaving the plate or film in this bath for two or three minutes it should be examined under a weak white light. When all the developed or metallic silver 2 of the original exposure has .disappeared the film is washed for about a minute. After the primary image 2 is completely dissolved and the plate well washed the emulsion side 3 is ex osed to white light and redeveloped.

at 4 y the original developer or by means.

" of the following: Anhydrous sodium sulphate 15 grams (135 grains), Amidol 5 grams (45 grains), and distilled water to 1000 cubic Y placed on a piece of sensitized carbon tissue 1n which a small amount of pigment has been incorporated with the gelatine coating 6 on the paper supporting sheet 23 during the process of manufacture, exposed to an enclosed 110 volt arc lamp, consuming about ten amperes of current at a distance of ten inches for a period of ten minutes. The tissue 6 is sensitized by `means of two per cent bichromate of potassium, and a safe edge is used as with ordinar autotype carbon tissue. The print is eveloped in water of about 110 F. Before the development it is squeegeed face down onto a piece of thin celluloid as a support during the development, the paper backing 23 removed and the unacted gelatine 22 washed off. As soon as dry the negative relief print 8 is placed on the drum 12 of the engraving machine, underneath a piece 10 of transparent or other Celluloid about .005 inch thick. To avoid the use of the paper support 23 the gelatine S maj' be applled to a thin transparent ce1- luloi 7 which is printed with the Celluloid face against the transparency so that the subsequent development with hot water to remove the soft gelatine 22 and retain the hardened portions 21 will commence immediately without the necessity of stripping off a paper support 23 as is common in the use of carbon tissue.

In the production of such gelatine relief prints 9 it is im ossible to always secure the same maximum eight of relief 19 hence the engraving steps must compensate for this variation by coordinating the lines per inch Z with" the included angle a of the V shaped graving tool or incisor 11. This relation is shown on Fig. 8. If the tool or graver angle a remains constant then the lines per inch Z must vary with changes in the extent of the relief 1'. Should the lines per inch l remain constant, at a given number, then the angle a. of the graver must change accordingly. In practice it is simpler to retain an average graver angle a for a given kind of results, depending on the kind of paper, etc. to be used in printing, and change thc lines per inch Z by means of change gears, such as are well known in cutting screw threads on a lathe.

The drum or cylinder 12 of the phonograph-like engraving machine is rotated at about 120 revolutions per minute. Paradoxically as it may seem the sharp point of the graver 11 pushes the superposed Celluloid sheet l0 away from in front of itself into the hollows 20 of the carbon relief 8. To assist in this a sapphire presser foot (not shown) located adjacent the graver overcomes variations in the surface tension of the Celluloid film on which the engraving 10 is being made.

The mechanism has been christened an Akrograph; relief printing results, Akrotones; andintaglio printing results, Akrogravures.

When stereotyping steps are not encountered these engraved films 10 can be cemented to a wood base 16 and printed from direct. In fact, for some time it has been held that the theoretical so-called cold stereotype could be used, but it has not, until relatively recently been possible to procure the dry-mats for stereotyping as they havenot been in practical use. 'Ihese dry-mats 15 are now available for distribution through the mails, thus eliminating the heavy transportation charges incurred prior to their use when boiler-plate was sent from metropolitan centers to the smaller dailies, etc., located in the country where metal duplicates of su'ch mats are made to be placed in the forms for subsequent restereotyping.

The dry mats 15 are produced on a press provided with a roller 13 and a horizontally movable bed 17. The engraved film 10 is placed on any suitable base 16, the mat is then laid on top and it is covered by a rubber blanket'll which presses the dry papiermch into the wideand deep grooves 24 and the narrow and shallow grooves 25 thus completing the mat 15 which may be subsequently placed in the usual casting box (not shown) and hot type met-al forced against it to form a stereotype 18.

A single engraved film 10 when placed on a suitable base has impressed thereon a dry relatively cold mat from which an individual mat may be produced to form a matrix for subsequent stereotyping. In ordinary practice the film 1Q is held on a base 16, against side slipping, by a trace of thin honey, or otherwise. It is made a part of the regular form associated with linotype slugs, displaytype, etc., etc., the wholebeing held in a chase as usual. On such a form the dry matis placed to cover its entire surface and the Awhole is subjected to pressure. After the form and mat havepassed under the pressure' roller, the impressed mat is removed leaving the engraved film 10 on its base in the same condition as when it was assembled with the other matter. The impressed mat, opposite any wide open spaces,is then backed up with gummed strips of considerable thickness so as to produce greater depth in the metal cast, wherever these open spaces occur. The mat so treated is afterward subjected to moderate heat to remove any moisture present in the adhering strips and it i's then placed in a curved mold of substantially the same diameter as the printing cylinder.' Melted type metal is then poured against the mat, to reproduce the printin face of the entire form a temperature as will not destroy the incision so held incisions of variable de th and width corresponding to the varying eights' of the relief are made in the film as the relief and the superimposed' film-are moved adjacent the incisor, which method consists in pressing a relatively cold dry mat into the incisions, and in subse uently depositing metal against the reversed incisions of the mat to form a sur-face for relief printing.

2. In an automat-ic engraving process for relief printing in which a photographic ne ative is reversed into a positive and a varia le height carbon relief. 1s fproduced from the positive over which a lm of celluloid is placed and both are held-incontact with each other on a suitable sup ort and while so. held incisions are made o varying depth and width in the su erposed film according to the eight of thev carbon relief variations in through a movementbetwen the support and the incisor, which method consists in pressing a cold dry mat into theincisions, and in depositing metal againstfthe reversed incisions produced in the ,mat to'form a printing surface.

' In testimony whereof I alix my signature.

,NOAH S. AMSTUTZ. i

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