US2634214A - Composition for a planographic image-forming pencil - Google Patents

Description

Patented Apr. 7, 1953 coMPos'rrIoNron A PLANOGRAPHIC IMAGE-FORMING PENCIL Charles HQVan Dusen, Jr., Willoughby, Ohio, and Oscar E. Weissenborn, Verona, N. J., "assignor's to =Addressograph Multigraph Corporation, WilmingtomDeL, a corporation of Delaware "NoDrawing. Application -May 18, 1951, a Serial No. 227,104

:2 Claims. 01. 106- 19) application is a continuation-in-part of iou r co -(pending application Serial No. 48,531, filed september 9,"l948, Patent No. 2,566,754,:and ilillfifle d "F- Planographic Image-Forming -Pencil and LeadTherefon Thisinvention relates-to aplanographic imagef'ormi'n'g pencil and to 'a so-called lead 'or writing rod therefor for use in forming plan'ographic images uponmaster planographic printing plates including aluminum and paper or like cellulose base master planographic printing plates. fli numberof problems are "encountered in the manufacture of *planographic image-forming "writingrodsbr so-called leads and pencils em- Fbo'dying the same which are :peculiar to such ip'lanographic image-forming pencils and which =are not encountered in the manufacture of common so-called lead pencils. Among these problems "are: A 'plan'ographic image-forming pencil must be capable :of forming an inscription or image'which will produce a satisfactory number or copies from the master plate upon which the image is written; itmust be capable of making uniform lines, that is to say, lines which are of substantially uniform width throughout their entire length upon the master plate; the writmg instrument, that is to say, the substantially cylindrical writing rod or so-called lead which is embodied inisuch apla'nographic pencil must be neither too soft so that the inscription or image formed thereby will wash off the plate readilyzor so thatit will produce lines which will vary in width as the pencil moves across a mastr aluminum or paper or'like planographicplate on which it is being used to write an image, and

' it must n'otbe sufficiently hard to scratch such masterplanographic printing plate; and it "must have "good ink-receptive and ink-retentive properties "so that it will be receptive to and will I retain the lithographic "inks used in making reproductions from the master plate.

Accordingly, an object of the present invention is to provide 'a new and improved image-form'- ing. planographic pencil embodying a writing inistrumentorso-called lead which has-good image- ;forming properties and which will produce images havingzgood ink-receptive and ink-wretentivepropi'rihich 'is' suflicientlyhard to enable it to make f; rm width upon a -paper or other graphi printing plate and to prevent the Ii made hereby from washing on the plate;

eities.11for planogr'aphicor lithographic inks? object er the nventi n is it prance 1 cylindrical writing rods or-so-called lea'ds of the new planographic pencil.

V :A further object of the inventionfis to anew and improved planographic image-forming lead or writing instrument for use in a'planographic image-forming pencil which may be employed in a planographic image-forming pencil of any suitable character including those "of the mechanically propelled type. I i:

Other and further objects of the present'im 'vention will be apparent from the followi'ngdescription and claims which describe "preferred embodiments of the invention and the principles thereof and what we now consider to be the best mode in which we have contemplated apply- 7 invention, may be that which is shown in the following example:

Example-No. 1

Partsbyweiht Nigrosine I v 35 Japan wax p 2 Aluminum stearate e 40 Methyl cellulose solution (binder) (one part dissolved in six parts of watenby weight) g 27.6

In the manufacture of the new planographic image-forming pencil, and the new plano'graphic image-forming lead or writing rod therefor, the n'igrosine and aluminum s'tearate referred 'toin the foregoing Example 'No. 1 may be mixed together in the dry state and the methyl "cellulose may be dissolved in approximately six times "its weight of water, whereupon the 'nigrosine-aluminum stearate mixture and the a'queous methyl cellulose binder solution may be thoroughly mixed for a period of two or three hours, in a suitable mixer. The Japan wax may then be melted to liquid form and added to the aforesaid mixture of nigrosine, aluminum 'stearate andmethfyl cellulose binder and the "resulting mixtureffur their thoroughly mixed for a period of swan-tars. The resulting base mixture is of dougf sistency and may be rolled and exams form of substantially eyup-ar'icai was I to suitable lengths to form the new pla'nog' 'phlc The thus prepared planographic image-form ing leads or substantially cylindrical rods may then be encased or enclosed in grooved wooden pencil casings in a conventional manner. This operation, as is well understood in the art, includes inserting the substantially cylindrical writing rods or so-called leads into a groove formed in one of two complementary sections of a wood or like pencil casing, adhesively securing the two complementary halves or sections of the pencil casing together with the substantially cylindrical writing rod or so-called .leadtherebetween; suitably shaping the outer -surface of the pencil casing as by forming hex- \agonal faces thereon; and then suitably finishing :the pencil casing as by sanding and painting the same.

' In addition to being encased in a grooved wooden casing the new planographic image- {forming leads or writing rods may, if desired, be employed in pencils of the mechanical type. It will thus be seen that the new planographic image-forming writing rods or so-called leads 'which are prepared according to the foregoing Example No. 1, are comprised of the dried reaction product of an intimate mixture of an aquelous solution of a binder, namely, a solution of ,methyl cellulose in water, and the balance a lmixture of the solid materials referred to in the foregoing Example No. 1, namely, nigrosine, Japan wax and aluminum stearate.

In place of the Japan wax specified in the foregoing Example No. l we may employ suitable equivalent quantities of one of the following sub- Tstances or mixtures thereof, namely, tallow, stearic acid, carnauba wax, bees wax, parafiin ,wax, and spermaceti.

1 The aqueous solution of methyl cellulose (binder) specified in the foregoing Example No. 1 may be employed within a rather wide range of from approximately ten per cent to approximately fifteen per cent, by weight, of the com- ;plete pencil base mixture. However, it; has been found that the resulting planographic imageforming pencil or writing rod becomes too weak if the percentage of the aqueous methyl cellulose binder is reduced below the minimum of ten percent, as specified, whereas if the percentage of the aqueous methyl cellulose binder is increased substantially in excess of the maximum of fifty per cent specified the writing or planofgraphic image-forming qualities of the resulting pencil or writing rod are unsatisfactory.

i vIn place of the aqueous solution of methyl ,cellulose specified in the foregoing Example No. l suitable equivalent quantities of the following -materials, or mixtures thereof, may be employed as the binder, namely, ethyl cellulose, carboxyl methyl cellulose, gum tragacanth, polyvinyl alcohol and clay.

Indulin may be employed in place of the nigro- :sine specified in the foregoing Example No. l in place of the aluminum stearate specified we also employ suitable equivalent quantities of lcalcium stearate or zinc stearate, or mixtures of ,these materials. l v 1, .Another composition. which may be employed Lill preparing the base for the new substantially-- 4 cylindrical planographic image-forming pencils or writing rods is illustrated in the following example in which all parts indicated are by weight:

Example No, 2

Parts by weight Nigrosine 35 Aluminum stearate 25 Inert mineral material (clay) 15 Methyl cellulose solution (binder) (one part dissolved in six parts water, by weight) 27.6

cal planographic image-forming Writing rod or instrument for the new planographic imageforming pencil enables a planographic imageforming pencil embodying the new planographic image-forming pencil or writin rod to slide or move easily over the surface of a planographic printing plate during the writing or image-forming operation; the nigrosine (or indulin substituted therefor) is an image-forming material and imparts necessary color to the substantially cylindrical planographic image-forming writing rod or instrument, namely a black color; the aluminum stearate, or other material substituted therefor, is also an image-forming material; and the methyl cellulose, with or without clay, serves as a binder to bind the various ingredients together.

The clay specified in the foregoing Example No. 2 serves as an inert mineral filler, adding bulk to the mixture and diluting the concentration of the nigrosine and aluminum stearate and it may also function as a binder. Such clay may be china clay or English clay or in place thereof talc or any other suitable inert filler material may be employed to add bulk to the mixture and also serve, in part, as a binder, if desired.

It has been found that the new planographic image-forming so-called leads or writing rods prepared according to the present invention have good image-forming properties, and that images formed thereby have good ink receptive properties for lithographic inks; that they are sufficiently hard to enable it to form good images, including lines of uniform width, on paper and like planographic printing plates; that they provide images which will not readily wash oil such plates; and that they provide images which will enable satisfactory editions or numbers of copies to be reproduced from a master paper or like planographic printin plate when the latter is employed in making reproductions in a rotary and improved planographic image-formingpenoil, and a new and improved planographic image- .forming writing rod or instrument for use therein, and a novel composition for making the same,

and that the invention has the desirable advantages and characteristics, and accomplishes its intended objects, including those hereinbefore pointed out and others which are inherent in the invention.

We claim:

1. A planographic image-forming pencil writing material consisting essentially of the dried productof an intimate mixture of the followin materials within a range of plus or minus ten per cent of each of the quantities specified, all parts being by weight:

Nigrosine 35 Aluminum stearate 25 Inert mineral material 15 Methyl cellulose solution (one part dissolved in six parts of water, by Weight) 27.6

2. A planographic image-forming pencil writing material consisting essentially of the dried product of an intimate mixture of the following materials within a range of plus or minus ten Nigrosine 35 I Aluminum stearate 25 Clay 15 I V 6 7 per cent of each of the quantities specified, all parts being by weight:

Methyl cellulose solution (one part dissolved in six parts of water, by weight) 27.6

CHARLES H. VAN DUSEN, JR. OSCAR E. WEISSENBORN.

REFERENCES CITED The following references are of record in the file of this patent:

Claims (1)

1. A PLANOGRAPHIC IMAGE-FORMING PENCIL WRITING MATERIAL CONSISTING ESSENTIALLY OF THE DRIED PRODUCT OF AN INTIMATE MIXTURE OF THE FOLLOWING MATERIALS WITHIN A RANGE OF PLUS OR MINUS TEN PER CENT OF EACH OF THE QUANTITIES SPECIFIED, ALL PARTS BEING BY WEIGHT: