US3573041A - Process for preparing a planographic printing plate - Google Patents

Process for preparing a planographic printing plate Download PDF

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Publication number
US3573041A
US3573041A US710729A US3573041DA US3573041A US 3573041 A US3573041 A US 3573041A US 710729 A US710729 A US 710729A US 3573041D A US3573041D A US 3573041DA US 3573041 A US3573041 A US 3573041A
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US
United States
Prior art keywords
chelate
image
printing plate
zinc
planographic printing
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Expired - Lifetime
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US710729A
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English (en)
Inventor
Jozef Leonard Van Engeland
Noel Jozef De Volder
Albert Lucien Poot
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Agfa Gevaert NV
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Agfa Gevaert NV
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    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G13/00—Electrographic processes using a charge pattern
    • G03G13/26—Electrographic processes using a charge pattern for the production of printing plates for non-xerographic printing processes
    • G03G13/28—Planographic printing plates

Definitions

  • a planographic printing plate is prepared by Xerographically developing a latent electrostatic image on a xerographic layer using an inorganic photoconductor adapted to provide zinc ions, the image being developed with a developing composition forming a hydrophobic deposit on the xerographic layer in the image areas.
  • the resultant xerographically developed layer is treated with an aqueous solution containing a hydrophilic zinc chelate or a compound capable of forming such a chelate with zinc ions.
  • This invention relates to a process for the preparation of a planographic printing plate and to the printing plate obtained therewith.
  • Planographic printing is based on the physical property of repellence of greasy materials for water.
  • the printing surface which is substantially flat contains the pattern of the image to be printed in terms of a differentiation in water-repellency.
  • a printing plate is prepared by affixing to a water-attractive, hydrophilic surface, a waterrepellent hydrophobic image, usually greasy, resinous or waxy in nature.
  • lithographic printing plate There are several methods known for preparing a lithographic printing plate. According to one of them use is made of a photoconductive insulating material such as an electrophotographic recording layer containing photoconductive zinc oxide dispersed in an electrically insulating binder. To prepare the printing surface said layer is electrostatically charged and image-wise exposed.
  • a photoconductive insulating material such as an electrophotographic recording layer containing photoconductive zinc oxide dispersed in an electrically insulating binder.
  • the electrostatic image according to the electrical sign of the electrostatically attractable developer particles in respect of the applied charge may be developed as a negative or a positive of the original to be reproduced.
  • the electrostatic image is rendered visible by applying a developer powder, which is held electrostatically to the charged areas of the sheet.
  • the powder image preferably composed of hydrophobic fusible powder particles may be fixed by heating. Normally the difference in hydrophobicity between the developed image parts and the non-covered areas of the recording layer is not high enough for high quality planographic printing and has to be increased. Therefore it has been proposed to chemically treat the recording layer in the undeveloped areas in order to make the said areas highly waterreceptive.
  • a photoconductive insulating recording layer comprising an electrically insulating binder having suspended therein an inorganic photoconductive substance which can provide zinc ions such as photoconductive zinc oxide, can be provided with an improved hydrophility by treating it with a compound capable of forming an hydrophilic chelate therewith, or by treating it with an already formed hydrophilic zinc chelatev
  • the water-solubility of the chelating compound can be improved by introducing one or more Water-solubilizing group(s) in its structure.
  • the compound may be a non-metal containing chelating compound, or a water-soluble metal chelate, for example formed by reaction of a non-metal containing chelating compound with a metal salt, e.g. a copper(II) or cobalt(II) salt.
  • a metal salt e.g. a copper(II) or cobalt(II) salt.
  • Preferably used compounds capable of forming a hydrophilic zinc chelate are represented by the following general formula:
  • the image-wise hydrophilization is carried out by treating the portions of the recording layer, which are not covered by the hydrophobic developing substance, with an aqueous liquid containing said chelating compound or chelate in dissolved form in a concentration comprised between 2 and 20 g. per liter.
  • the chelating compounds and chelates used in the present invention may be combined with other known zinc oxide hydrophilizing compounds such as, e.g., water-soluble cyanoferrates(III) and water-soluble cyanoferrates(II) and mineral and organic acids forming a hydrophilic zinc salt precipitate in aqueous medium e.g. orthophosphoric acid and water-soluble salts thereof, citric acid and tartaric acid.
  • other known zinc oxide hydrophilizing compounds such as, e.g., water-soluble cyanoferrates(III) and water-soluble cyanoferrates(II) and mineral and organic acids forming a hydrophilic zinc salt precipitate in aqueous medium e.g. orthophosphoric acid and water-soluble salts thereof, citric acid and tartaric acid.
  • the resistance to wear of the hydrophilized portions of the recording layer can be increased by the use in combination with the chelating compounds of hydrophilic colloids which may be applied together or after the treatment with said compounds.
  • Suitable hydrophilic colloids for that purpose are e.g. gum arabic, alginic acid, water-soluble alginates e.g. ammonium alginate, caseinates, gelatin, polyacrylic acid esters, polystyrene sulphonic acid, polyvinyl alcohol, and carboxymethylcellulose.
  • a treatment with hydrophilic precipitating or hardening agents for these colloids has proved to be advantageous; so, use can be made of formaldehyde as protein hardener and heavy metal salts forming a precipitate e.g. with alginates.
  • hydrophilized areas may be treated with a hygroscopic substance e.g. an hygroscopic salt or organic compound containing a great amount of hydrophilic groups e.g. as is the case in polyols such as glycerine.
  • a hygroscopic substance e.g. an hygroscopic salt or organic compound containing a great amount of hydrophilic groups e.g. as is the case in polyols such as glycerine.
  • the hydrophilizing action of the hydrophilizing agent may be improved by a pre-treatment of the developed and fixed recording layer with a softening or swelling agent for the binder occasionally in combination with a wetting agent improving the penetrating power of the hydrophilizing agent in the recording layer. In this way much more zinc oxide grains are reached by the hydrophilizing agent and hydrophilized.
  • swelling agents preferably water-miscible compounds such as acetone and methylethylketone are used.
  • the aqueous phase of the printing ink or the liquid of the damping system may contain lower (C C aliphatic alcohols.
  • watersoluble mineral and organic acids can be used e.g. nitric acid, sulphuric acid, hydrogen chloride, boric acid, acetic acid and lactic acid.
  • the electrophotographic recording layer is rendered water-receptive on the areas to be hydrophilized after the printing master has been mounted on the press, thus obviating any separate immersion treatment.
  • the hydrophilizing treatment of the said layer may be carried out by means of an absorbent pad impregnated with the aqueous chelating compound solution.
  • Electrophotographic recording materials which are especially suited to be used in the preparation of a planographic printing plate are e.g. described in the published Dutch patent applications 6608814 and 6608815.
  • Any known process for forming the electrostatic latent image and hydrophobic image may be used.
  • the hydrophobic image is formed by the subsequent steps of producing an electrostatic image on a photoconductive zinc oxide/ hydrophobic binder layer by integrally electrostatically charging that layer, subsequently image-wise exposing and developing the latter with a hydrophobic developer powder which is fixed to the recording layer e.g. by heating.
  • the powder image can be formed by the known dry carrier-toner development or by a liquid development based on electrophoresis wherein charged hydrophobic particles are attracted from an electrically insulating liquid to the charged areas of the recording layer.
  • a liquid development based on electrophoresis wherein charged hydrophobic particles are attracted from an electrically insulating liquid to the charged areas of the recording layer.
  • an aqueous liquid is image-wise applied to an electrostatic charge pattern present in a zinc oxide containing recording layer.
  • Said aqueous liquid can be an aqueous dispersion of hydrophobic material which after evaporating the aqueous liquid forms a hydrophobic deposit in correspondence with the printing parts.
  • the hydrophilizing chelating compounds used in the present invention can be applied in the aqueous liquid of the damping system of a planographic printing device or in the hydrophilic liquid phase of a planographic printing ink consisting of an emulsion of a lipophilic liquid phase in a hydrophilic liquid phase.
  • Results obtained according to that embodiment are better than those obtained by a common hydrophilizing pretreatment of the plate, in other words the reproducibility of the quality of the copies is improved and the amount of copies of good quality which can be produced without substantial degrading of the printing plate is increased.
  • EXAMPLE 1 A layer of photoconductive material consisting of photoconductive zinc oxide dispersed in an insulating binder (3 parts by weight of zinc oxide to one part by weight of resin binder) was coated on a sheet of aluminium foil laminated to a paper support.
  • the resin binder contained on a weight basis of styrene-buta diene copolymer (80/20), 20% of silicon resin (Silicon Resin SR-82 supplied by General Electric-Silicone Products Department, Waterford, N.Y., U.S.A.).
  • the recording layer was charged with a negative corona with a tension of -6000 v. on the corona wires and exposed through a graphic original. Development was carried out using the magnetic brush technique with iron particles as carrier and gilsonite as fusible toner.
  • the powder image was fixed to the layer by heating for seconds at C.
  • a cotton pad was impregnated with a solution containing the following ingredients:
  • the plate was rubbed lightly with the cotton pad while on the press, and printing started.
  • the quality of prints was very good.
  • Example 1 was repeated excepting that instead of the chelating compound 1, compound 2 of the table was used. Plate quality was fully equivalent to that of Example 1.
  • Example 1 was repeated excepting that instead of the chelating compound 1 compound 3 was used.
  • EXAMPLE 6 A layer of photo-conductive material consisting of photoconductive zinc oxide dispersed in an insulating binder (6 parts by weight of zinc oxide to one part by weight of binder) was coated on a flexible aluminium foil.
  • the binder is prepared from a mixture of EPOK X-l772 (ammoniacal alkyd resin salt marketed as a 66 to 68% (by weight) aqueous solution by British Resin Products) and EPOK-W-980l (a 72 to 75% aqueous solution of a melamine-formaldehyde resin marketed by British Resin Products).
  • EPOK X-l772 ammoniacal alkyd resin salt marketed as a 66 to 68% (by weight) aqueous solution by British Resin Products
  • EPOK-W-980l a 72 to 75% aqueous solution of a melamine-formaldehyde resin marketed by British Resin Products
  • the cured recording layer is charged with a negative corona with a tension of 6000 v. on the corona-wires and exposed to a line-copy.
  • the electrostatic image is electrophoretically developed by means of an electrophoretic developer obtained by diluting the hereinafter described concentrated developer composition in a ratio of 1000 by means of Shellsol T (trade name) carbon black (average particle size nm.) g.
  • Shellsol T (trade name)750 ccs.
  • the fixing agent composition is prepared as follows: 500 g. of Alkydal L67 (trade name of Wegriken Bayer AG, Leverkusen, Germany, for a linseed oil (67% by weight) modified alkyd resin) and 500 ccs. of white spirit containing 11% by weight of aromatic compounds are heated at 60 C. till a clear solution is obtained and cooled.
  • EXAMPLE 7 A layer of photoconductive material consisting of photoconductive zinc oxide dispersed in a ratio of 8 to 1 by weight in Alkydal V10 (trade name of Wegriken Bayer AG, Leverkusen, Germany for a 43% by weight solution of a styrolated alkyd resin modified with 35% by weight of a drying vegetable oil) as binding agent is coated onto a baryta-coated paper of g./sq. m. Said. recording layer is suited for the powder development described in Example 1 and for the electrophoretic development in Example 6. Hydrophilization on the press after development is carried out as described in Example 1. With the obtained offset-master 500 high quality prints were produced.
  • Process for preparing a planographic printing plate comprising the steps of developing a latent electrostatic image on a photoconductive insulating recording layer containing an inorganic photoconductive substance which can provide zinc ions, the developing being carried out with a developing composition forming an image-wise hydrophobic deposit on said layer, fixing said image-wise hydrophobic deposit and treating the portions of the recording layer free of hydrophobic deposit with an aqueous solution containing a hydrophilic zinc chelate or a compound capable of forming a hydrophilic zinc chelate with said zinc ions, said chelate being of zinc and a compound represented by the general formula wherein:
  • R is hydrogen, or an alkyl radical having from 1 to 5 carbon atoms
  • each of Z and Z represents the atoms necessary for completing a nitrogen-containing ring or ring systern.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Printing Plates And Materials Therefor (AREA)
US710729A 1967-03-06 1968-03-06 Process for preparing a planographic printing plate Expired - Lifetime US3573041A (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
GB00475/67A GB1192602A (en) 1967-03-06 1967-03-06 Process for Preparing a Planographic Printing Plate
GB10476/67A GB1198122A (en) 1967-03-06 1967-03-06 Process for Preparing a Planographic Printing Form
GB10477/67A GB1198123A (en) 1967-03-06 1967-03-06 Process for Preparing a Planographic Printing Master

Publications (1)

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US3573041A true US3573041A (en) 1971-03-30

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US710729A Expired - Lifetime US3573041A (en) 1967-03-06 1968-03-06 Process for preparing a planographic printing plate
US710730A Expired - Lifetime US3592640A (en) 1967-03-06 1968-03-06 Process for preparing a planographic printing master
US710723A Expired - Lifetime US3617266A (en) 1967-03-06 1968-03-06 Process for preparing a planographic printing form

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US710730A Expired - Lifetime US3592640A (en) 1967-03-06 1968-03-06 Process for preparing a planographic printing master
US710723A Expired - Lifetime US3617266A (en) 1967-03-06 1968-03-06 Process for preparing a planographic printing form

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US (3) US3573041A (en))
BE (1) BE711704A (en))
CH (1) CH500512A (en))
DE (1) DE1622950A1 (en))
FR (1) FR1558045A (en))
GB (3) GB1198122A (en))
NL (1) NL6803164A (en))

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3807305A (en) * 1968-07-15 1974-04-30 Itek Corp Metal photographic plate comprising a silver halide process
US3807304A (en) * 1968-07-15 1974-04-30 Itek Corp Photographic process for producing coherent metallic image bonded to a roughened support and products produced thereby
US3970455A (en) * 1973-06-04 1976-07-20 Itek Corporation Electrostatic lithographic printing process utilizing hydrophilizing composition
US4043811A (en) * 1976-07-29 1977-08-23 Addressograph Multigraph Corporation Conversion solutions for planographic masters
US4053319A (en) * 1973-06-04 1977-10-11 Itek Corporation Hydrophilizing composition for lithographic printing plates
US4058470A (en) * 1975-10-24 1977-11-15 A. B. Dick Company Liquid developer composition for lithographic masters
US4070969A (en) * 1976-07-16 1978-01-31 Minnesota Mining And Manufacturing Company Method for strengthening lithographic printing plate images
JP3222667B2 (ja) 1993-11-16 2001-10-29 株式会社巴川製紙所 平版印刷用不感脂化処理液

Families Citing this family (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE381109B (sv) * 1972-09-28 1975-11-24 Commw Of Australia Forfarande for offsettryckning
JPS5122405B2 (en)) * 1973-10-26 1976-07-09
NL7606078A (nl) * 1975-06-12 1976-12-14 Dow Chemical Co Werkwijze voor het bereiden van een bevochti- gingsoplossing voor lithografische drukken.
DE2934897C1 (de) * 1978-02-06 1984-09-20 Napp Systems (USA), Inc., San Marcos, Calif. Desensibilisierungsloesung fuer fotoempfindliche Diazodruckplatten
JPS6023099A (ja) * 1983-07-19 1985-02-05 Tomoegawa Paper Co Ltd オフセツト印刷用不感脂化処理液
GB8501868D0 (en) * 1985-01-25 1985-02-27 Byrne P Board game
JPS6277994A (ja) * 1985-10-01 1987-04-10 Nikken Kagaku Kenkyusho:Kk オフセツト印刷用電子写真版の不感脂化処理液
JPH01133795A (ja) * 1987-11-19 1989-05-25 Nikken Kagaku Kenkyusho:Kk オフセツト印刷用電子写真版の不感脂化処理液
JP2622753B2 (ja) * 1988-06-27 1997-06-18 石原産業株式会社 オフセット印刷マスターの作成方法
US5565290A (en) * 1991-07-30 1996-10-15 Fuji Photo Film Co., Ltd. Desensitizing solution for offset printing
JP2884988B2 (ja) * 1993-04-20 1999-04-19 岩崎通信機株式会社 オフセット印刷用不感脂化処理液
US5525458A (en) * 1993-09-02 1996-06-11 Tomoegawa Paper Co., Ltd. Desensitizing solution for lithographic platemaking

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2023669A (en) * 1933-01-06 1935-12-10 Art of printing
BE591935A (en)) * 1959-06-18
NL266999A (en)) * 1959-08-04
US3245784A (en) * 1961-10-16 1966-04-12 Minnesota Mining & Mfg Lithographic master and process of preparation
US3106158A (en) * 1962-01-22 1963-10-08 Rca Corp Method of preparing lithographic printing plates
DE1897467U (de) * 1963-11-27 1964-07-30 Eduard Winkler Appbau G M B H Rastwerk fuer drehschalter, insbesondere stufenschalter.

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3807305A (en) * 1968-07-15 1974-04-30 Itek Corp Metal photographic plate comprising a silver halide process
US3807304A (en) * 1968-07-15 1974-04-30 Itek Corp Photographic process for producing coherent metallic image bonded to a roughened support and products produced thereby
US3970455A (en) * 1973-06-04 1976-07-20 Itek Corporation Electrostatic lithographic printing process utilizing hydrophilizing composition
US4053319A (en) * 1973-06-04 1977-10-11 Itek Corporation Hydrophilizing composition for lithographic printing plates
US4058470A (en) * 1975-10-24 1977-11-15 A. B. Dick Company Liquid developer composition for lithographic masters
US4070969A (en) * 1976-07-16 1978-01-31 Minnesota Mining And Manufacturing Company Method for strengthening lithographic printing plate images
US4043811A (en) * 1976-07-29 1977-08-23 Addressograph Multigraph Corporation Conversion solutions for planographic masters
JP3222667B2 (ja) 1993-11-16 2001-10-29 株式会社巴川製紙所 平版印刷用不感脂化処理液

Also Published As

Publication number Publication date
DE1622950A1 (de) 1971-01-14
FR1558045A (en)) 1969-02-21
GB1198122A (en) 1970-07-08
GB1192602A (en) 1970-05-20
BE711704A (en)) 1968-09-06
NL6803164A (en)) 1968-05-27
CH500512A (de) 1970-12-15
US3592640A (en) 1971-07-13
US3617266A (en) 1971-11-02
GB1198123A (en) 1970-07-08

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