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
• • 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
  • B41N3/08—Damping; Neutralising or similar differentiation treatments for lithographic printing formes; Gumming or finishing solutions, fountain solutions, correction or deletion fluids, or on-press development

Definitions

• This invention relates to the art of planographic printing, in which a suitable plate or foundation, on which there is an image formed of ink receptive material, usually greasy ink, is wet with an ink repelling fiuid, then inked over to deposit ink only on the image, which is then transferred to a sheet of paper usually by way of a blanket in offset printing, the image being reinked and foundation being maintained, wet or ink repellent as repeated copies are printed.
• the plate For successful operation, the plate must be ink receptive to a degree where it receives and holds the image forming material and printing ink, and hydrophilic to a degree where it will receive and hold suflicient ink repellent fluid to limit the reinking of the plate to the image.
• plates with an organic coating, impregnation or foundation designed for planographic purposes change their properties with age before use, and the prints obtained from fresh plates are different from those which have aged. Further, the properties of such plates vary in the manufacturing process so that plates formed at the beginning of a run may be satisz factory but those made later in run are relatively poor due to the material changing its physical and chemical properties during the run.
• the present invention obviates these difficulties by avoiding the necessity of maintaining this balance in the plate as it is prepared for printing or inscription, by preparing or selecting a plate, the surface of which is inherently, or made so by design, ink receptive so that ink applied initially and in printing copies will be received and held by the plate producing the desired image on the plate, then rendering the surface of the plate forming the background around the image predominantly hydrophilic and ink repellent before the plate is used for printing. This is done preferably by applying to the image-bearing plate a solution, repelled by the image-forming material, which forms a hydrophilic film on the plate masking the background around the image, and which filmis insoluble in the fountain fluid of the press.
• the body of the plate may be made of any suitable or desirable material such as metal, cast plastic material, printing papers, wet-strength paper, parchmentized paper, or any of these with or without treated surface strata or coatings or films so long as it is strong enough when processed to withstand wetting and mechanical abrasion when used as a plate on a planographic printing machine; provided it is sufficiently ink receptive to image is produced thereon and preferably immediately or shortly before prints are to be made from the plate.
• the coating may be of a kind which would deteriorate with age.
• an insolubilizing reagent such as mineral acids, for example hydrochloric, sulphuric or phosphoric acid and certain organic acids such as citric, tartaric, and tannic acid, the film which forms on the plate becomes permanently water insoluble upon drying.
• an acidified aqueous solution including a. water-soluble salt of a carboxymethyl ether of cellulose to the image-bearing surface of the plate and allow the same to solidify by drying into an insoluble tough film.
• This film is predominantly hydrophilic and protects the foundation of the plate against excessive water absorption and .gives it additional wet strength, leaving the image predominantly ink receptive, sharp and well defined and protected from invasion and undermining by the wetting solutions used in printing from the plate, as so often happens with plates heretofore proposed.
• the masking film being predominantly and substantially uniformly hydrophilic when wet, prevents the formation of undesired background frequently present on prints made by plates heretofore proposed, especially on long runs.
• a masking film of solidified carboxymethylcellulose is capable of being formed without including the insolubilizing agent in the coating solution, and that an aqueous solution of a salt, of a carboxymethyl ether of cellulose may be applied to the image-bearing plate, dried, and then subjected to insolubilizing after-treatment.
• the film may be rendered' insoluble by including in the'wetting or fountain solution used in printing copies. or by application in any way, of a precipitant salt such as aluminum sulphate and/or an insolubilizing mineral acid such as phosphoric, or certain org'anic acids such as tannic acid.
• the reagent may be added to the solution in the fountain of the, printing press, or it may be brushed or rubbed on the plate before the press is 65 run, as desired.
• the film may be cast and insolubilized by including the reagent in the coating solution, or in the fountain solution, or by rubbing or brushing it on the undried plate before it is applied to the press.
• suitable plasticizers such as glycerine
• Inert fillers such a China clay may be added to the 15 filming solution especially if the coated plate is I to receive inscriptions or additional printing before use.
• the present invention may be practiced with the use of a metal plate, in which case it is not necessary or even desirable to remove the oxide formed on theplate, as this is more ink receptive than the polished and clean plate, and the film-producing coating adheres to the metal plate whether the latter is oxidized or not.
• a metal plate in which case it is not necessary or even desirable to remove the oxide formed on theplate, as this is more ink receptive than the polished and clean plate, and the film-producing coating adheres to the metal plate whether the latter is oxidized or not.
• the plate is to receive its image by typewriter type, it is better to use a non-metallic plate, for the metal plate is unavoidably embossed by the type blows and its continued use will blunt the type badly.
• any printed sheet or page such as a page or clipping from a book or magazine, after being suitably mounted so that sary .and waterproofed and strengthened if the sheet is too water absorbent or weak foruse in the printing machine, may be coated with the hydrophilic masking solution of the present invention, and then run on the press to make duplicate' copies by the planographic method.
• This is of great commercial and practical advantage, especially when the number of copies wanted is not great enough to justify making planographlc plate by photographic methods.
• any sheet having an image thereon which repels the coating solution may be used, I have evolved a method whereby practically an unlimited number of copies. may be made by the planographic method starting with one original master. practicing this method,-the master is made or prepared as above specified or otherwise, and a few copies printed from the master, preferably the first few, are set aside. The master on the machine is then used until just before the printed image falls below acceptable quality, and then it ing material used is discarded. One of the prints set aside is then coated and becomes itself a master which is placed on the planographic press cylinder and as many copies as possible are made from this. The other print-masters are used successively as they are needed. With this method, should it be desired to print 150,000 copies for example, it would merely be necessary to set aside nine of the prints made from the original master and then use these one after another using the original and each of the substitute masters to make approximately 1500 copies, again for example.
• any paper having sufllcient wet strength, or which may be given wet strength by treatment may be used to make a commercially satisfactory and salable master sheet, for most purposes it will be found desirable and preferable to use a prepared master sheet, and this sheet may. according to my invention which is described and claimed in my other application, Serial No. 586,825, filed April 5, 1945, be impregnated with carboxymethylcellulose with or without suitable inert fillers and with or without suitable softening agents such as glycerine.
• the method of making a planographic printing plate which includes the steps of applying a solution includin a salt of acarboxymethyl ether of cellulose to the face of the plate bearing an ink receptive water repellant image, the solution being aqueous and therefore being repellant to the image; drying the plate to produce a solidified predominantly hydrophilic film of said carboxymethyl ether of cellulose salt on the surface of the plate except over the image which remains ink receptive; and applying to the plate a reagent to insolubilize said film.
• the method of making a planographic printing plate which includes the steps of applying a solution includin a salt of a carboxymethyl ether of cellulose to the face of the plate bearing an ink receptive water repellant image, the solution being aqueous and therefore repellant to the image and forming a predominantly hydrophilic film of said carboxymethyl ether of cellulose salt on the surface of the plate except over the image which remains ink receptive; and while the film is still wet, applying to the plate a reagent to render the film water insoluble and ink repellant.
• the method of making a planographic printing plate which includes the steps of applying a solution of sodium carboxymethyl ether of cellulose to the face of the plate bearing an ink receptive water repellant image, the solution being aqueous and therefore being repellant to the image and forming a predominantly hydrophilic film of sodium carboxymethyl ether of cellulose on the surface of the plate except over the image which remains ink-receptive; and applying to the film a dilute aqueous solution of aluminum sulphate to render the film water insoluble and to wet the film and render it repellant to ink.
• the method of making a planographic printing plate which includes the steps of applying a solution including a salt of a carboxymethyl ether of cellulose to the face of the plate bearing an oleous image, the solution being aqueous and therefore being repelled by the oleous image and forming a predominantly hydrophilic film of said carboxymethyl ether of cellulose salt on the surface of the plate except over the oleous image which remains predominantly oleophilic; and applying to the film a dilute solution of insolubilizing acid to render the film water insoluble.
• the method of making a planographic printing plate which includes the steps of applying a solution including a salt of a carboxymethyl ether of cellulose to the face of the plate bearing an oleous image, the solution being aqueous and therefore bein repelled by the oleous image and forming a predominantly hydrophilic film of said the plate, the solution being aqueous and therefore being repelled by the image; and drying the plate to produce a substantially solid water insoluble predominantly hydrophiilc film comprising essentially a water insoluble carboxymethyl cellulose compound on the surface of the plate except over the image matter which remains water repellant.
• the method of making a planographic printing plate which includes the steps of printing form matter on an oleophilic cellulosic plate with oleous material; typewriting with water repellant material matter to fill-in the form printed on the plate; applying a solution including a salt of a carboxymethyl ether of cellulose to the printed and typed image-bearing face of the plate, the solution being aqueous and therefore being repelled by the oleous printed and filled-in image; drying the plate to produce a solidified predominantly hydrophilic film of said carboxymethyl ether of cellulose salt on the surface of the plate except over said image; and applying to the film a wetting solution containing an insolubilizing reagent for said carboxymethyl ether of cellulose salt from the fountain of the press before the plate is inked in the press.
• the method of printing duplicates by the planographic method which includes the steps of preparing a planographic printing master by producing on a plate an ink receptive water repellant image; applying a solution including a salt of a carboxymethyl ether of cellulose to the image-bearing face of the plate, the solution being aqueous and therefore being repellant to the image; drying the plate to produce a solidified predominantly hydrophilic film of said carboxymethyl ether of cellulose salt on the surface of the plate except for the surface covered by the image; wetting the image-bearing film-carrying surface of the plate with a reagent containing wetting solution to render the film water insoluble and repellant to oleous material; applying oleous printing ink to the image-bearing surface of the plate to ink the image; transferring the ink from the image to a copy-receiving medium; and maintaining the film wet with said reagentwetting solution and reinking the image as additional duplicates are made by transferring the image to copy-recei
• the method of printing duplicates by the planographic method which. includes the steps of preparing a planographic printing master by producing on a plate an ink receptive water repellant image; applying a solution of sodium carboxymethyl ether of cellulose to the imagebearing face of the plate, the solution being aqueous and therefore being repelled by the image and forming a predominantly hydrophilic film of said sodium carboxymethyl ether of cellulose on the surface of the plate except for the surface covered by the image; applying the plate to a planographic printing machine while the film is still wet; wetting the image-bearing film-carrying surface of the plate with a reagent-containing v 8 solution to render the-film water insoluble and repellant to oleous material; applying oleous printing ink to the image-bearing surface of the plate to ink the image; transferring the ink from the image to a copy-receiving medium; and maintaining the film wet with said reagent-containing solution and reinking the image as additional' duplicates are
• the method of printing duplicates by the planographic method which includes the steps of preparing a planographic printing master by producing on a plate an ink receptive water repellant image; applying a solution of aluminum carboxymethyl ether of cellulose to the imagebearing face of the plate, the solution being aqueous and therefore being repelled by the image and forming a predominantly hydrophilic film of said aluminum carboxymethyl ether of cellulose on the surface of the plate except for the surface covered by the image; applying the plate to a planographic printing machine; wetting the image-bearing film-carrying surface of the plate with a wetting solution including aluminum sulphate to render the'film water insoluble and repellant to oleous material; applying oleous printing ink to the image-bearing surface of the plate to ink the image; transferring the ink from the image to a copy-receiving medium; and maintaining the film wet with said salt-containing solution and reinking the image as additional duplicates are made by transferring the image to copy-rece
• the method of printing duplicates by the planographic method which includes the steps of preparing a planographic printing master by applying to a sheet having an ink receptive water repellant image to be printed a solution including a salt of a carboxymethyl ether of cellulose to the image-bearing face of the sheet, the solution being aqueous and therefore being repellant to the image; drying the coating to produce a predominantly hydrophilic film of said carboxymethyl ether of cellulose salt on the' surface of the sheet except for the surface covered by the image; wetting the image-bearing surface of the sheet with fountain solution containing an insolubilizing reagent to render the film insoluble and ink repellant; applying printing ink to the image-bearing surface of the sheet to ink the image; transferring the ink from the image to a copy-receiving medium; and maintaining the film wet and reinking the image as additional duplicates are made by transferring the image to copyreceiving media.
• the method of printing duplicates by the planographic method which includes. the steps of preparing a planographic printing master by formin a substantially solid image masking film comprising essentially a water insoluble carboxymethyl cellulose compound on the image-bearing face of a sheet inscribed with an ink receptive water repellant image: wetting the image-bearing film-carrying surface of the sheet to render the film repellant to printing ink material; applying printing ink to the image-bearing surface of the sheet to ink the image; transferrin the ink from the image to copy-receiving sheets to make duplicate copies; and selecting one or more of said duplicate copies and forming on the printed surface of each a substantiallyisolid protective image-masking film comprising essentially a water insoluble carboxymethyl cellulose compound whereby the selected and treated dupliplanographic method which includes the steps of selecting any printed sheet having the desired printed image thereon; forming a substantially solid protective image-masking film comprising essentially a water insoluble carboxymethyl cellulose compound on the image-be
• a planographic plate having an ink receptive water repellant image thereon and having a water insoluble hydrophilic film of a carboiiymethyl ether of cellulose forming a substantially solid, plate-attached mask around the image over the background of the plate.
• a planographic master comprising a cellulosic plate having on a face thereof an ink receptive water repellant image and on the same face a hydrophilic water insoluble film of an insolubilized carboxymethyl ether of cellulose providing a substantially solid, flexible, plateattached mask around the image and over the background of the plate.
• a planographic master comprising a cellulosic plate having on a face thereof an ink receptive water repellant image and on the same face a hydrophilic film of aluminum carboxymethyl ether of cellulose providing a substantially solid, flexible, plate-attached mask around the image and over the background of the plate.
• a planographic master comprising a cellulosic plate having on a face thereof an ink receptive water repellant image and on the same face a substantially solid hydrophilic film comprising essentially a water insoluble compound of carboxymethylcellulose providing a mask around the image and over the background of the plate.
• a pianographic master form to receive matter to be filledin on a typewriter, comprising a flexible cellulosic plate having printed thereon with oleous ink a blank form subsequently to be filled-in, said plate having thereon a film of a water insoluble carboxymethyl ether of cellulose forming a substantially solid, flexible, plate-attached mask around the oleous ink constituting the form and over the background thereof, which when dry is receptive to the fill-in ink material.
• a planographic master form to receive matter to be filled to/the fill-in ink material.
• the method of making a planographic printing plate which includes the steps of producing on a plate an ink-receptive water-repellant image; applying a self-insolubilizing solution including essentially a compound of carboxymethyl cellulose to the image-bearing surface of the plate, the solution beingaqueous and therefore repelled by the image; and then drying the plate toform a substantially solid masking film comprising essentiallya water insoluble carboxymethyl cellulose compound around the image.
• the method of making a planographic printing plate which includes the steps of producing on a plate an ink-receptive water-repellant image; applying an acidified solution including essentially a compound of carboxymethyl cellulose to the image-bearing surface of the plate, the solution being aqueous and therefore repelled by the image; and then drying the plate to form a substantially solid masking film comprising essentially a water insoluble carboxymethyl cellulose compound around the image.
• a planographic plate having an ink-receptive water-repellant image thereon and having a substantially solid hydrophilic film comprising essentially a water insoluble carboxymethyl cellulose compound forming a mask around the image over the background of the plate.

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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)
• Manufacture Or Reproduction Of Printing Formes (AREA)

Priority Applications (7)

Applications Claiming Priority (4)

Publications (1)

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Cited By (11)

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Citations (13)

Family Cites Families (4)

• 0
  • BE BE529582D patent/BE529582A/xx unknown
• 1945
  • 1945-03-08 US US581720A patent/US2582347A/en not_active Expired - Lifetime
  • 1945-12-22 US US637087A patent/US2655101A/en not_active Expired - Lifetime
• 1951
  • 1951-10-09 GB GB23502/51A patent/GB766532A/en not_active Expired
  • 1951-12-20 FR FR1054259D patent/FR1054259A/fr not_active Expired

Patent Citations (13)

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