US2503679A - Bonding planographic ink - Google Patents

Description

Patented 11, 1950 BONDINGPLANOGRAPHIC INK Douglas A. Newman, Port Washingto Y., asignor to Columbia Ribbon and Carbon Mannfactnring Company, Inc., Glen Cove, N. Y., a

corporation of New York No Drawing. Application May 7, 1943,

' Serial No. 486,101

8 Claims. (Cl. 101-1493) My invention relates to the art of planographic printing and more particularly to a method of bonding the ink used in producing the image upon the planographic printing sheet to the surface thereof.

The object of the invention is to produce an image upon the printing sheet which will be more firmly attached and more firmly bonded to the surface of the sheet and which will be more durable and less subject to being undercut and loosened by repeated applications of the aqueous ink repellent fluid used in printing and which will be capable of a greater number of satisfactory copies than is commonly possible with methods and inks heretofore used for the purpose.

The invention is aimed particularly at the preparation and bonding of the printing image produced by means of a typewriter or printing press or stylus or otherwise upon the surface of a planographic printing sheet of the fibrous or cellulosic material variety, such as those having a paper base with a grained or otherwise prepared surface, or of parchmentized paper, but it may be used also with other types of printing sheets.

It is well known to those skilled in the art of planographic printing that the "life" of the image on the printing sheet is the governing factor in limiting the number of clean, clear, legible copies that can be made from it. It is also well known that the chief factor influencing the durability or life of the image is the presence or absence of a sufliciently firm, tenacious bond between the ink of the printed image and the surface of the sheet. When the bond is weak the result is that the aqueous ink repellent fluid which is applied to the surface of the printing sheet between the applications of printing ink to the image, penetrates into the surface of the sheet at the edges of the image, finds its way under the ink which forms the image and loosens it from the surface of the sheet. Or, the aqueous ink repellent fiuid may penetrate the layer of ink at points away from the edges of the image, where the bond between the ink and the surface is weak, and s undermine and loosen the ink. Or, the aqueous fiuid may enter the fibres of the surface and displace the ink upon the outer surface of the fibres. Subsequent passage of the inking roller over the surface of the sheet picks of! the loosened particles of ink,

leaving a minute area'of the image uncoated with ink.

Thus gradually the edges and internal portions 'of the characters of the printing image become ragged and the body of the image becomes weak and has uninked points from which the ink has 2 been lifted so that ultimately the printed copies become unsatisfactory and the life of the printing sheet is exhausted. Ordinarily this deterioration and failure of the image occurs when somewhere between 500 and 2000 copies have been printed from a parchmentized paper printing sheet, depending upon the skill and carefulness of the operator.

Any method which will cause the ink of the printing image to become more firmly and tenaciously bonded to, or interlocked with, the surface of the printing sheet, thus preventing the penetration of the aqueous ink repellent fluid under the surface of the sheet at the edges of the characters and undermining the ink coating, and

which prevents the loosening of the coating in the body of the characters, will produce a greater number of satisfactory copies and is a distinct advance in the art. Such is the object of the invention, which it accomplishes in the following manner.

I first prepare a planographic printing ink either by incorporating a solid substance in a finely divided state in a vehicl in which it is not soluble at ordinary temperatures or by forming a solution of a substance in a vehicle, which substance may be acted upon subsequently, as will hereinafter appear. I may choose a substance which, while insoluble in the vehicle used, is capable of being acted upon by a volatile liquid either to dissolve it or to cause it to swell, or to chemically react upon it to cause a precipitate to form. Or, I may choose a substance which is soluble in the vehicle used but which can be acted upon by a liquid to alter its physico-chemical state, as will hereinafter be described.

Under the first mentioned procedure I prepare an ink which is a suspension of finely divided solid matter in a vehicle in which it is not soluble, said solid matter being soluble in a volatile solvent. I next prepare a printing image upon a plan" ographic sheet with this ink. I then apply to the image upon the sheet a volatile liquid which is capable of acting with the solid matter of the ink to effect a change in its physical or its chemical condition or both, which will result in an increase in the bond or union between the ink and the surface of the sheet upon the evaporation of the liquid.

There are several types of changes in the physico-chemical condition which the solid material in the ink may be caused to undergo which will result in increasing the bond between the ink and the surface of the printing sheet. One such change is the solution, or partial solution, of a solid material in a solvent or-in a mixture of asolvent and a non-solvent. For example, my planographic ink may be prepared by grinding to extreme fineness in a medium in which it is not soluble, a hard organic material which is readily soluble in volatile solvent.' Thus I may use an ester gum which is readily soluble in alcohol and grind it to an impalpable powder in a medium such as mineral oil in-which it is not soluble, to form the body of the ink. To this I may, if desired, but not necessarily, add a pigment to give a distinct; color and to make the image more plainly visible. To produce a black ink I may add a small quantity of carbon black. I may also control or modify the physical condition of the ink or its consistency by the addition of an appropriate amount of a hardener or of a plasticizer so as to adapt the ink to application to cloth or p per ribbon for use in a typewritter or for application to paper for use as carbon paper or to adapt it to use as a printing ink on a printing press, all as well understood by one skilled in the art.

After the image has been formed of such an ink upon the surface of a printing sheet by any of the conventional methods, I apply to the image a solvent of the ester gum, such as alcohol or a mixture of alcohol and water. The result is a solution or partial solution of the particles of ester gum in the solvent. This solution of the ester gum penetrates the pores of the grained or porous or fibrous surface of the printing sheet much more completely and thoroughly than do planographic inks heretofore commonly used. I next evaporate the solvent leaving the solid ester gum and the pigment, if present, and other non-volatile constituents of the ink, if any, firmly bonded to, and interlocked with, the surface of the sheet.

A second type of change which may be caused to take place and which results in a markedly increased bond between the ink of the image and the surface of the sheet is a swelling of the particles of solid matter of the ink in the pores and among the fibres of the printing sheet with the result that they cannot be readily dislodged by the action of the aqueous repellent fluid used in printing.

For example, I may prepare an ink by incorporating finely divided egg albumen in a vehicle composed of oleic acid and tricresyl phosphate and add thereto, if desired, a soluble coloring matter such as peerless black or nlgrosine base. After forming the printing image upon the surface of the printing sheet by such conventional processes as are described above I apply to the image a liquid composed of a mixture "of water, glycerine and phosphoric acid. The reaction between the finely divided particles of albumen and the water results in a swelling of the particles of albumen within the pores and among the fibres of the surface of the sheet and produces a greatly increased bond between the ink and the surface.

A third type of physico-chemical change which I may utilize to augment the bond between the ink and the surface of the printing sheet is the precipitation of a solid or semi-solid or rubbery material within the pores or between the fibres of the surface by chemical reaction.

For example, I may incorporate Vinylite resin in a vehicle composed of butyl Carbitol and, if desired, I may add thereto a pigment such as nigroslne base or carbon black. After forming the image upon the surface of the printing sheet by conventional methods as described above with an ink of this type I wet the surface of the sheet tion or precipitation of a rubbery mass in the pore and among the fibres of the sheet which serves to firmly bond the ink to-the surface. This precipitate is maintained in its rubbery condition throughout the life of the printing sheet by the continued application thereto of the aqueous repellent used in' printing.

Under each of the three types of actions, result ing in three types of physico-chemical changes described above there are other materials which may be used to carry out the invention with a greater or lesser degree of satisfaction. I do not intend to limit my invention to the use of any particular materials or combinations of materials or to exclude the. use of other materials or combinations of materials capable of acting as described herein, or otherwise, except as limited and bounded by the appended claims.

It is preferable that the ink be composed partly of a material possessing the following characteristics. It should be sufllciently hard and brittle to be reducible to a substantially impalpable powder. It should be readily acted upon by the liquid used to cause the desired physico-chemical change which will result'in the desired bonding action upon the surface of the sheet. It must be oleophilic or capable of receiving ,the oily or greasy ink used in printing copies of the image after the physico-chemical change caused by the action of the fluid has taken place.

In the practice of the invention I proceed as follows. Having selected a material possessing suitable characteristics such as are described above, I make an ink by methods well known in the art and with this ink I prepare a typewriter ribbon or a carbon paper or a printers ink and imprint the desired image upon the surface of a planographic printing sheet 1. e., a sheet which is receptive toward aqueous ink-repellent fluids as well as toward oil-receptive water-repellent ink, by such of the conventional methods as best suits the purpose. To this image I apply a fluid which will act upon the ink of the image to produce the desired physico-chemical change.

For example, if my ink is selected from those made from materials of the first described type, the soluble type, it may comprise ester gum ground or dispersed in a mineral oil in which it is not soluble. After printing the image on the planographic sheet with this ink I apply a volatile solvent of the ester gum, such as alcohol, or a mixture of alcohol and water, to the image by means of a small tuft of cotton wet with the solvent liquid. By partially saturating a wad of cotton with the solvent and gently applying it to the sheet without rubbing until that portion of the sheet which is occupied by the image'is moistened with the solvent, I dissolve or soften and partially dissolve the ester gum of the ink.

This solution of gum, or softened and partially dissolved gum, enters the pores of the surface of the sheet and into the interstices between the fibres. I next evaporate the solvent liquid leaving the ester gum and other non-volatile constituents of the ink, if any, firmly bonded to the surface of the sheet. The evaporation of the solvent may be effected by exposing the sheet to room temperature for a few minutes or the evaporation may be hastened by subjecting the sheet to a moderately elevated temperature for a shorter length of time.

The printing sheet is now ready for use and I proceed to print in the conventional manner as many copies as may be desired, which number may be many more than has been heretofore possible by usual methods.

If an ink is selected which is composed of other types of materials which give other types of reactions such as swelling or precipitation, I treat the image formed therefrom with an appropriate fluid to cause the particular change in the physico-chemical state of the ink as is hereinabove described, such as swelling or precipitation.

Having described my invention so that one skilled in the art to which it pertains may practice it, I now state what I believe to be new and for which I pray that Letters Patent be granted.

I claim:

1. In the art of planographic printing which comprises forming an oily-ink-receptive waterrepellent image on a planographic printing sheet, applying an aqueous ink-repellent fluid to the surface of the sheet, and inking the image with printing ink, the improvement which comprises forming said image on a paper base sheet having a porous surface with an oil-receptive, water-repellent ink having thoroughly mixed therethrough an at most partly active bonding constituent having the capacity to penetrate the porous surface of the sheet; applying to the image-containing areas of the sheet a volatile liquid having therein an agent capable of reacting with said constituent to alter the physico-chemical condition of said constituent which penetrates the porous surface of the sheet'so as to increase the bonding power thereof; and evaporating said volatile liquid, whereby the image is rendered resistant to undermining by the aqueous inkrepellent fluid applied to said sheet during printing.

2. In the art of planographic printing which comprises forming an oily-ink-receptive waterrepellent image on a paper base planographic printing sheet, applying an aqueous ink-repellent fluid to the surface of the sheet, and inking the image with printing ink, the improvement which comprises forming said image on a sheet having a porous surface with an oil-receptive, water-repellent ink containing finely divided undissolved ester gum uniformly dispersed therein in a vehicle in which it is insoluble, applying to the image-containing areas of the sheet a volatile liquid solvent for said ester gum whereby the gum is caused to penetrate the porous surface of the sheet, and evaporating the solvent, whereby the image is rendered resistant to undermining by the aqueous ink-repellent fluid applied to said sheet during printing.

3. In the art of planographie printing which comprises forming an oily-ink-recepti-ve waterrepellent image on a planographic printing sheet, applying an aqueous ink-repellent fluid to the surface of the sheet, and inking the image with printing ink, the improvement which comprises forming said image on a sheet having a porous surface with an oil-receptive, water-repellent ink containing finely divided undissolved ester gum uniformly dispersed in mineral oil, applying to the image-containing areas of the sheet a liquid containing a volatile solvent for said ester gum whereby the gum is caused to penetrate the porous surface of the sheet, and evaporating the liquid, whereby the image is rendered resistant to undermining by the aqueous ink-repellent fluid applied to said sheet during printing.

4. In the art of planographic printing which comprises forming an oily-ink-receptive waterrepellent image on a planographic printing sheet, applying an aqueous ink-repellent fluid to the surface of the sheet. and inking the image on a sheet having a porous surface with printingink, the improvement which comprises forming said image with an oil-receptive, water-repellent ink containing flnely divided undissolved ester gum uniformly dispersed in mineral oil, applying to the image-containing areas of the sheet a volatile liquid containing alcohol whereby the gum is caused to penetrate the porous surface of the sheet and evaporating the liquid, whereby the image is rendered resistant to undermining by the aqueous ink-repellent fluid applied to said sheet during printing.

5. In the art of planographic printing which comprises forming an oily-ink-receptive waterrepellent image on a planographic printing sheet, applying an aqueous ink-repellent fluid to the surface of the sheet, and inking the image with printing ink, the improvement which comprises forming said image on a sheet having a porous surface with an oil-receptive, water-repellent ink containing an undissolved solid bonding constituent having the capacity to penetrate the porous surface of the sheet and capable of swelling, and then bonding the image to the sheet by applying to the image-containing areas of the sheet, a. liquid agent capable of causing swelling of said constituent within the pores of the surface of said sheet, whereby the image is rendered resistant to undermining by the aqueous ink-repellent fluid applied to said sheet during printing.

6. In the art of planographic printing which comprises forming an oily-ink-receptive waterrepellent image on a planographic printing sheet, applying an aqueous ink-repellent fluid to the surface of the sheet, and inking the image with printing ink, the improvement which comprises forming said image on a sheet having a porous surface with an oil-receptive, water-repellent ink containing undissolved solid egg albumen dispersed in mineral oil, and applying an aqueous liquid to the image-containing areas of the sheet, to cause the albumen to swell within the pores of the surface of the sheet, whereby theimage is rendered resistant to undermining by the aqueous ink-repellent fluid applied to said sheet during printing.

'7. In the art of planographic printing which comprises forming an oily-ink-receptive waterrepellent image on a planographic printing sheet, applying an aqueous ink-repellent fluid to the surface of the sheet, and inking the image with printing ink, the improvement which comprises forming said image on a sheet having a porous surface with an oil-receptive, water-repellent ink containing a dissolved bonding constituent having the capacity to penetrate the porous surface of the sheet, and then bonding the image to the sheet by applying to the image-containing areas of the sheet, a liquid agent capable of forming a precipitate with said bonding constituent of the ink which penetrates the porous surface of the sheet, whereby the image is rendered resistant to undermining by the aqueous inkrepellent fluid applied to said sheet during printing.

8. In the art of planographic printing which comprises forming an oily-ink-receptive waterrepellent image on a planographic printing sheet, applying an aqueous ink-repellent fluid to the surface of the sheet, and inking the image on a sheet having a porous surface with printing ink,

the improvement which comprises forming said image with an oil-receptive, water-repellent ink containing a vinyl resin dissolved in butyl carbito] having the capacity to penetrate the porous surface of the sheet, applying to the image-containing areas of the sheet an agent comprising an aqueous solution of glycerine, phosphoric acid and gum arable, whereby the vinyl resin is precipitated as a rubbery deposit within the pores oi the surface of the sheet, and whereby the image is rendered resistant to undermining by the aqueous ink-repellent fluid applied to said sheet during printing.

' DOUGLAS A. NEWMAN.

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

UNITED STATES PATENTS Number Name Date 316,251 Eberle Apr. 21, 1885 1,065,884 Hesse June 24, 1913 Number Name Date 1,141,224 Wawrziniok June 1, 1915 1,249,390 Hasburg an--. Dec. 11, 1917 1,408,816 McClellan Mar. 7, 1922 1,690,427 Oliver Nov. 6, 1928 1,931,610 Johnsione Oct. 24, 1933 1,972,313 Price Sept. 4, 1934 2,027,435 Kallander Jan. 14, 1938 2,192,482 Schroeder Mar. 5, 1940 2,254,072 Jenkins Aug. 26, 1941 2,336,292 Pike: Dec. 7, 1943 2,342,! 13 Wescott Feb. 29, 1944 FOREIGN PATENTS Number Country Date 9,899 Great Britain July 14, 1887 397,385 Great Britain Aug. 24, 1933 OTHER REFERENCES The Lithographer-s Manual, Waltwin Publishing Co. (1949), 1776 Broadway, New York city. pages 186 and 187. Copy in Division 17.