US2655864A - Method of making planographic plates - Google Patents

Method of making planographic plates Download PDF

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Publication number
US2655864A
US2655864A US637088A US63708845A US2655864A US 2655864 A US2655864 A US 2655864A US 637088 A US637088 A US 637088A US 63708845 A US63708845 A US 63708845A US 2655864 A US2655864 A US 2655864A
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United States
Prior art keywords
coating
paper
water
image
plates
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US637088A
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English (en)
Inventor
Douglas A Newman
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Columbia Ribbon and Carbon Manufacturing Co Inc
Original Assignee
Columbia Ribbon and Carbon Manufacturing Co Inc
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Filing date
Publication date
Priority to BE508935D priority Critical patent/BE508935A/xx
Application filed by Columbia Ribbon and Carbon Manufacturing Co Inc filed Critical Columbia Ribbon and Carbon Manufacturing Co Inc
Priority to US637088A priority patent/US2655864A/en
Priority to CH297859D priority patent/CH297859A/de
Application granted granted Critical
Publication of US2655864A publication Critical patent/US2655864A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41C—PROCESSES FOR THE MANUFACTURE OR REPRODUCTION OF PRINTING SURFACES
    • B41C1/00—Forme preparation
    • B41C1/10—Forme preparation for lithographic printing; Master sheets for transferring a lithographic image to the forme
    • B41C1/1091—Forme preparation for lithographic printing; Master sheets for transferring a lithographic image to the forme by physical transfer from a donor sheet having an uniform coating of lithographic material using thermal means as provided by a thermal head or a laser; by mechanical pressure, e.g. from a typewriter by electrical recording ribbon therefor
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41N—PRINTING PLATES OR FOILS; MATERIALS FOR SURFACES USED IN PRINTING MACHINES FOR PRINTING, INKING, DAMPING, OR THE LIKE; PREPARING SUCH SURFACES FOR USE AND CONSERVING THEM
    • B41N3/00—Preparing for use and conserving printing surfaces
    • B41N3/03—Chemical or electrical pretreatment
    • B41N3/036—Chemical or electrical pretreatment characterised by the presence of a polymeric hydrophilic coating

Definitions

  • This invention relates to the manufacture of planographic printing plates, suitable for use in planographic printing processes in which the surface of a plate on which an image is formed of ink-receptive material (usually a greasy ink) is wetted with an aqueous ink-repelling fountain fluid, then inked over to deposit ink only on the image, the latter being then transferred to a sheet of paper, usually by way of a blanket as in offset printing, the image being repeatedly reinked and the foundation being maintained wet or ink-repellent as repeated copies are printed.
  • ink-receptive material usually a greasy ink
  • this invention relates to planographic printing plates having a paper foundation which can be inscribed with an oleophilic image-forming material for use in a planographic printing process of the aforesaid type,
  • planographic plates heretofore used were sensitive to soiling with finger prints or the like which were reproduced on the printed copies. Such plates therefore required inordinate care in handling during preparation of a master copy, and up to the time they were used for printing.
  • a paper printing plate is provided on its printing surface with a film or coating of a water-insoluble carboxy-methyl cellulose compound (1. e., a carboxymethyl ether of cellulose or a salt or other derivative thereof) especially a water-insoluble metal derivative or salt of carboxy-methyl cellulose, the coating remains stable and does not change during storage,
  • a water-insoluble carboxy-methyl cellulose compound (1. e., a carboxymethyl ether of cellulose or a salt or other derivative thereof) especially a water-insoluble metal derivative or salt of carboxy-methyl cellulose
  • the surface of the plate is sufficiently oleophilic to receive an ink-receptive image, and to retain the image tenaciously during use; while the background is sufliciently hydrophilic to absorb water from the fountain solution and repel ink applied during printing.
  • the absorption of water from the fountain solution employed in printing is retarded and reduced by the coatings provided in accordance with my invention, so that troubles heretofore experienced involving reduction or loss of the image do not occur.
  • the background portion of the plate consistently maintains its hydrophilic ink-repellent character, preventing background specks from forming, and consistently retains a true image applied to it on the surface of the coating.
  • planographic printing plates having a paper foundation, and a coating on the printing surface thereof of a water insoluble metal derivative or salt of a carboxy-methyl cellulose, particularly a copper salt or derivative of carboxymethyl cellulose, or a mixture of the copper salt or derivative with such other salts or derivatives as those of aluminum, iron and chromium have especially desirable properties.
  • Such plates when dried, are adapted to receive an image inscribed or imprinted thereon with an oleophilic image-forming medium, and to retain the image tenaciously during printing; while the uninscribed background, which moistened Iith an aqueous fountain solution, consistently repels the printing ink yielding clear backgrounds. even when used for printing an exceedingly large number of copies.
  • Such plates are not subject to aging, and do not change their characteristics when stored for an indefinitely long period.
  • Plates prepared in accordance with my invention are very clean to handle so that they do not show thumb prints or finger marks, which usually appear on metal plates or other coated lithographic plates.
  • errors may be easily deleted with a pencil eraser, several times at the same point on the sheet if necessary, without injuringthe ink-repellent or image-receptive properties of the background, and without causing any perceptible change in the resulting copies after the correction is made.
  • This is especially advantageous, in that a typist can prepare master copies at normal speed, since minor errors can be readily corrected and do not necessitate retyping or reprinting the entire copy. or a tedious repair operation after erasure.
  • Planogra-phic plates can be prepared in accordance with my invention in a number of ways.
  • the simplest, and therefore the preferred method involves coating the paper with an aqueous composition containing a water soluble carboxymethyl cellulose salt or compound dissolved therein, drying the coating, and then insolubilizing the resulting film by treatment with a solution of a precipitant or coagulant reagent, particularly a coagulant metal compound.
  • the coating composition is applied to the paper preferably in the form of a continuous web from which the plates can be later cut, for example, by
  • paper which has been brush-coated with the carboxy-methyl cellulose solution and dried is preferably given a second coating with a similar composition, and again dried before subjecting it to treatment with the coagulant or precipitant metal compound.
  • the insolubilizing solution is applied to the carboxymethyl cellulose coated paper as' a wash (e. g. by coating devices or by tub-sizing) and the paper is then dried and calendered.
  • the sheet Before coating or after the intermediate or final drying, or after calendering, the sheet may be provided with a water-resistant backing, for example, by coating with a solution of a waterrepellent, resinous or plastic material in a volatile organic solvent, e. g. a solution of Polystyron (i. e. a resinous styrene polymer) in ethyl acetate.
  • a solution of a waterrepellent, resinous or plastic material in a volatile organic solvent e. g. a solution of Polystyron (i. e. a resinous styrene polymer) in ethyl acetate.
  • a Polystyron backing has been found especially satisfactory in that it not only Waterproofs the back of the plate, but gives it additional body without too much stiffness which would interfere with convenient handling of the .plate in a typewriter or printing machine.
  • the coating composition employed in accordance with my invention preferably contains, in addition to a water-soluble carboxy-methyl cellulose compound, an inert filler such as colloidal clay, barium sulphate, calcium carbonate or the like, to provide a surface having a substantial tooth, which possesses improved holdingpower for the ink applied to the image.
  • an inert filler such as colloidal clay, barium sulphate, calcium carbonate or the like
  • plasticizers such as glycerine can be included in the composition to insure or maintain the pliability of the film.
  • Readily volatile alcohols such as methanol or ethanol can also be included in the mixture to accelerate drying of the film.
  • the foundation sheet be made of paper having relatively high wet strength, so that the plate will have sufiicient body to be conveniently handled and applied to the printing press, and will have sumcient resistance to mechanical abrasion in use.
  • a water leaf strip from a paper-making machine may be passed through a size tub containing a solution for increasing the wet strength of the paper.
  • a fiber-bonding, absorptionlimitingmaterial is included in the pulp and the paper is formed as a wet-strength, limited-absorption paper.
  • a material such as a melamine or urea-formaldehyde resin, or a reaction product of these materials with a carboxy-methyl cellulose compound can be incorporated in the paper as a fiber-bonding, water-absorption-limiting material, either by addition to the pulp before the paper is prepared, or by impregnation after the paper is formed.
  • the web thus prepared is heated and dried, the aforesaid materials become coagulated or hardened and the paper foundation has its fibers bonded together and rendered resistant to penetration by'water.
  • Example 1 Calendered water leaf sheets, prepared from long-fibered pulp to which a melamine resin is added during manufacture to improve the wet strength of the resulting paper, is brush-coated with a composition made by dissolving the aluminum salt of carboxy-methyl cellulose in aqueous ammonia, adding a plasticizer and a lower alcohol, and mixing colloidal clay with the resulting solution until a uniform slurry is obtained.
  • the mixture has the following composition:
  • aqueous ammonia containing about 28 /2% of NI-la 5238 parts of water 180 parts of colloidal clay
  • CuSO4 copper sulphate
  • Al2(SO4)a aluminum sulphate
  • FeCla ferric chloride
  • Cl'Oa chromium trioxide
  • Example 2 Paper suitable for the foundation of a planographic printing plate, e. g., paper of the type employed in Example 1 is brush-coated with a uniform slurry composed of:
  • mixtures of metallic compounds advantageously having a total concentration of about 5% can be used to obtain planographic plates having similarly advantageous properties.
  • solutions containing 5% of copper sulphate and /2% of chromium trioxide; or 2 of copper sulphate and 2 /2% of aluminum sulphate have been found satisfactory.
  • the concentration of carboxy-methyl cellulose compound in the aqueous solution employed to form the coating composition is preferably about 3 to 5% in the case of the sodium compound, or about 1 to 3% in the case of the aluminum compound (which is dissolved in aqueous ammonia or other aqueous alkaline solution).
  • the coating on the paper preferably amounts to about 8 to 9 lbs. or more, per ream of 24" x 38" sheets.
  • the amount of coating can be readily controlled by adjusting the proportions of ingredients in the coating composition, varying the number of coatings, or the amount of composition applied in each coating treatment. In the foregoing examples, each brush-coated treatment results in formation of a coating of about 4 pounds per ream so that the two treatments described produce a coating on the finished sheets of about 8 lbs. per ream.
  • Desired variations in the character of the insolubilized carboxy-"nethyl cellulose film can be obtained by varying the type of coagulant or precipitant employed in the process as illustrated in Examples 1 and 2.
  • a single metal compound it has been found that copper salts produce the most satisfactory film for most purposes, the copper compound of carboxy-methyl cellulose having a gelatinous nature, and yielding a coating of especially desirable properties.
  • they when mixtures of coagulant metal compounds are employed, they preferably include a cop er salt such as copper sulphate.
  • the coagulan is advantageously used in a concentration of about 5%, although the concentration may be varied over a relatively wide range.
  • High wet-strength paper for use as a foundation for the plates of my invention can be advantageously made as disclosed in my copending application, Serial Number 586,825, by combining a concentrated melamine resin preparation (e. g. the product commercially available under the name of Melmac No. 7278) with a 2% aqueous solution of the sodium salt of a carboxymethyl cellulose; grinding the resulting precipitate to a colloidal slurry, adding the slurry to the paper pulp so as to incorporate it inthe paper, or impregnating the paper as it leaves the paper machine by applying the slurry thereto in a size tub, and drying and heating the paper to cause bonding of the fibres by the added material, thus forming paper of high wet strength and resistance to water absorption.
  • a concentrated melamine resin preparation e. g. the product commercially available under the name of Melmac No. 7278
  • a aqueous solution of the sodium salt of a carboxymethyl cellulose e. g. the product commercially
  • a solution formed by mixing other melamine resins e. g. Melmac No. 7277 which do not form a precipitate with dilute carboxy-methyl cellulose salt solutions with a 2%solution of sodium carboxy-methyl cellulose can be added to the paper pulp or used to impregnate the paper from a size tub.
  • Methylolurea or lower urea-formaldehyde polymers can be used instead of melamine resins.
  • the plate When the plate is to be used, its coated surface is typed, imprinted or inscribed with the desired image, using an oleophilic, ink-retaining, water-repellent, image-forming medium.
  • the plate is then fastened on the cylinder of a planographic printingmachine, and wetted with the aqueous wetting solution employed in the fountain of the machine.
  • No reagent capable sistant backing of waterproofing plastic e. g., of reacting with the coating on the plate is required in the fountain solution, and accordingly the latter does not change its composition during use.
  • Water alone can be used; or water containing such non-reactive materials as gum thickeners, wetting agents or buflers, generally'used in fountain solutions, can be employed.
  • oleous ink is applied from an inking roller to the image-bearing surface of the plate, the ink adhering only to those portions of the plate which are inscribed with the oleous image, while being repelled by the background portions of the plate constituted by the coating moistened with the aqueous fountain solution.
  • the inked image is then transferred to a printing blanket, used in offset printing and then applied to the sheet on which the copy of the image is to be made.
  • Planographic plates prepared in accordance with this invention can be employed for making 6000 to 10,000 copies without substantial deterioration in 'the quality of the duplicate copies of the image. If desired, the inked plate can also be applied for direct printing of copies, the image in this case being the reverse of the matter to be duplicated on the copies.
  • the paper foundation can be printed or inscribed with an oleous image-forming medium to produce a water-repellent image before application of the soluble carboxy-methyl cellulose solution, the latter being repelled by the image and thus coating only the uninscribed portion of the plate.
  • the coating of carboxy-methyl cellulose is converted to an insoluhie metal derivative as described above, and the plate is dried and calendered.
  • the uninscribed portions of the plate can then be inscribed with an image-forming medium, and the plate can be used to make copies of the pre-formed as well as the later-formed image.
  • plates prepared according tomy invention can be dried after use for duplicating an image inscribed thereon, a further inscription made on the background, and the plate used to make duplicate copies bearing the original as well as the later inscribed image.
  • the filler and/or plasticizer can be omitted in preparing the surface of a pianographic plate in accordance with my invention, the paper foundation being coated one or more times with an aqueous solution of a water-soluble carboxymethyl cellulose compound having a concentration, for example of about 1% to 5%, the coating being dried to form a film after each application, and the film being insolubilized in the manner described above by conversion to a waterinsoluble metal derivative or salt or carboxymethyl cellulose.
  • the process of preparing a master which comprises coating the surface of a paper foundation with a composition comprising an aqueous solution of a water-soluble carboxymethyl cellulose compound; drying the resulting coating; treating said coating with an aqueous solution of metal compounds consisting essentially of copper salts and aluminum salts in about equal parts by weight to coagulate the carboxymethyl cellulose; drying the coagulated coating; and inscribing an ink-receptive, water-repellent image on the surface of said coating.
  • the process of preparing a master which comprises coating the surface of a paper foundation with a composition comprising an aqueous solution of a water-soluble carboxymethyl cellulose compound; drying the resulting coating; treating said coating with an aqueous solution of metal compounds consisting essentially of copper salts and chromium salts in the ratio by weight of about 10:1 respectively to coagulate the carboxymethyl cellulose; drying the coagulated coating; and inscribing an ink-receptive, water-repellent image on the surface of said coating.
  • the process of preparing a master which comprises coating the surface of a paper foundation with a composition comprising an aqueous solution of a water-soluble carboxymethyl cellulose compound; drying the resulting coating; treating said coating with an aqueous solution of metal compounds consisting essentially of copper salts, aluminum salts, iron salts and chromium compounds in the ratio by weight of about 6:2:1:1 respectively to coagulate the carboxymethyl cellulose;
  • the process of preparing a master which comprises coating the surface of a paper foundation with a composition comprising an aqueous solution of a water-soluble carboxymethyl cellulose compound; drying the resulting coating; treating said coating with an aqueous solution of metal compounds consisting essentially of copper sulphate, aluminum sulphate, ferric chloride and chromium trioxide in the ratio by weight of about 6:2:1:1 respectively to coagulate the 'carboxymethyl cellulose; drying the coagulated coating; and inscribing an ink-receptive, water-repellent image on the surface of said coating.
  • the process of preparing a master which comprises coating the surface of a paper foundation with a composition comprising an aqueous solution of a water-soluble carboxymethyl cellulose compound, and colloidal clay suspended therein as a filler; drying the resulting coating, the amount of said composition being such as to yield a dry coating of about 4 lbs. per ream of 24" x 38" sheets; repeating the foregoing coating and drying operations so as to form a coating of about 8 to 9 lbs.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Mechanical Engineering (AREA)
  • Optics & Photonics (AREA)
  • Manufacturing & Machinery (AREA)
  • Printing Plates And Materials Therefor (AREA)
US637088A 1945-12-22 1945-12-22 Method of making planographic plates Expired - Lifetime US2655864A (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
BE508935D BE508935A (enrdf_load_stackoverflow) 1945-12-22
US637088A US2655864A (en) 1945-12-22 1945-12-22 Method of making planographic plates
CH297859D CH297859A (de) 1945-12-22 1952-01-14 Verfahren zur Herstellung von Flachdruckplatten.

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US637088A US2655864A (en) 1945-12-22 1945-12-22 Method of making planographic plates

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Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2766137A (en) * 1952-06-06 1956-10-09 Johnson & Johnson Treated fibrous product and method
US2776912A (en) * 1952-04-30 1957-01-08 Hercules Powder Co Ltd Process of coating paper with a gellable water-soluble cellulose derivative and pigment and gelling said coating
US2776911A (en) * 1952-04-30 1957-01-08 Hercules Powder Co Ltd Process of coating paper with gellable water soluble salt of cellulose sulfate and pigment and gelling said coating
US2778301A (en) * 1953-05-22 1957-01-22 Warren S D Co Coated paper planographic printing plate
US2805621A (en) * 1954-02-10 1957-09-10 Standard Register Co Paper planographic plate
US2941466A (en) * 1956-08-24 1960-06-21 Columbia Ribbon Carbon Mfg Planographic printing platess
US3031958A (en) * 1953-10-23 1962-05-01 Columbia Ribbon & Carbon Method of manufacture of paper planographic plate
US3311489A (en) * 1965-09-24 1967-03-28 Oxford Paper Co Transfer sheet and method of preparing
US3650805A (en) * 1967-06-30 1972-03-21 Saburo Imoto Method of manufacturing coated paper

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB821375A (en) * 1956-09-18 1959-10-07 Oxford Paper Co Improvements in coating compositions and planographic printing plates
DE1194879B (de) * 1957-02-16 1965-06-16 Eastman Kodak Co Verfahren zum Herstellen lithographischer Druckplatten

Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1625714A (en) * 1925-05-03 1927-04-19 Argentographica U S A Ltd Photocollographic printing plate and method for producing the same
US2130241A (en) * 1934-06-18 1938-09-13 Seaman Paper Company Method for coating paper
US2214565A (en) * 1938-01-26 1940-09-10 Champion Paper & Fibre Co Coated paper and method of making the same
US2230981A (en) * 1937-10-25 1941-02-04 Toland William Craig Printing plate
US2236545A (en) * 1938-10-08 1941-04-01 Du Pont Cellulose glycolic acid
US2302816A (en) * 1941-01-11 1942-11-24 Toland Planographic printing
US2331858A (en) * 1941-03-06 1943-10-12 Dow Chemical Co Preparing solutions of cellulose glycollic acid salts
US2370517A (en) * 1941-08-07 1945-02-27 Dow Chemical Co Insolubilization of water-soluble cellulose ethers
US2373287A (en) * 1943-07-27 1945-04-10 Method of preparing printing plates
US2542784A (en) * 1945-09-21 1951-02-20 Addressograph Multigraph Planographic printing plate and method of preparing the same

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1625714A (en) * 1925-05-03 1927-04-19 Argentographica U S A Ltd Photocollographic printing plate and method for producing the same
US2130241A (en) * 1934-06-18 1938-09-13 Seaman Paper Company Method for coating paper
US2230981A (en) * 1937-10-25 1941-02-04 Toland William Craig Printing plate
US2214565A (en) * 1938-01-26 1940-09-10 Champion Paper & Fibre Co Coated paper and method of making the same
US2236545A (en) * 1938-10-08 1941-04-01 Du Pont Cellulose glycolic acid
US2302816A (en) * 1941-01-11 1942-11-24 Toland Planographic printing
US2331858A (en) * 1941-03-06 1943-10-12 Dow Chemical Co Preparing solutions of cellulose glycollic acid salts
US2370517A (en) * 1941-08-07 1945-02-27 Dow Chemical Co Insolubilization of water-soluble cellulose ethers
US2373287A (en) * 1943-07-27 1945-04-10 Method of preparing printing plates
US2542784A (en) * 1945-09-21 1951-02-20 Addressograph Multigraph Planographic printing plate and method of preparing the same

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2776912A (en) * 1952-04-30 1957-01-08 Hercules Powder Co Ltd Process of coating paper with a gellable water-soluble cellulose derivative and pigment and gelling said coating
US2776911A (en) * 1952-04-30 1957-01-08 Hercules Powder Co Ltd Process of coating paper with gellable water soluble salt of cellulose sulfate and pigment and gelling said coating
US2766137A (en) * 1952-06-06 1956-10-09 Johnson & Johnson Treated fibrous product and method
US2778301A (en) * 1953-05-22 1957-01-22 Warren S D Co Coated paper planographic printing plate
US3031958A (en) * 1953-10-23 1962-05-01 Columbia Ribbon & Carbon Method of manufacture of paper planographic plate
US2805621A (en) * 1954-02-10 1957-09-10 Standard Register Co Paper planographic plate
US2941466A (en) * 1956-08-24 1960-06-21 Columbia Ribbon Carbon Mfg Planographic printing platess
US3311489A (en) * 1965-09-24 1967-03-28 Oxford Paper Co Transfer sheet and method of preparing
US3650805A (en) * 1967-06-30 1972-03-21 Saburo Imoto Method of manufacturing coated paper

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Publication number Publication date
CH297859A (de) 1954-04-15
BE508935A (enrdf_load_stackoverflow)

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