Classifications

• • 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

• the invention relates to a method for preserving ready-to-print planographic printing forms, in order to protect the plates during storage from being used for printing against the ingress of air and dirt and, at the same time, to permanently hydrophilize their non-printing surface areas.
• DE-OS 26 59 754 describes the use of aqueous polyvinyl alcohol solutions for the same purpose.
• the known preservatives normally have an effect which is sufficient for many carrier materials. It turned out, however, that this later worn protective film is not always sufficient to prevent the appearance of sound during printing.
• special care must be taken in printing forms with anodically oxidized aluminum as the carrier material in order to prevent oleophilic contamination of the carrier surface exposed by development, e.g. B. by dust or dirt particles or by fingerprints, before preservation, since such contaminants are usually only difficult to remove without attacking the print layer or the carrier surface.
• contamination can easily occur not only in the time between development and preservation, but also during development or during the manufacture of the printing plate by self-coating.
• the object of the invention was to provide a preservation method which allows the image background of planographic printing plates not only to be protected against later contamination, but also to be freed from smaller oleophilic contaminants which are already present.
• the invention relates to a method for preserving ready-to-print planographic printing forms, in which the planographic printing form is treated with an aqueous solution of a water-soluble film-forming high-molecular organic compound and a hydrophilizing acid and dried.
• the process according to the invention is characterized in that an organic phosphonic acid is used as the hydrophilizing acid.
• the invention ensures that a clean, toneless background is obtained when printing, even if this background already contained oleophilic contaminants on the plate before preservation.
• Suitable organic phosphonic acids are aromatic, heterocyclic, aliphatic and cycloaliphatic low and high molecular weight phosphonic acids and their derivatives.
• Examples are vinylphosphonic acid, polyvinylphosphonic acid, 2-phosphono-ethane-1-sulfonic acid, 3,3-diphosphono-pimelic acid, vinylphosphonic acid monomethyl ester, 4-chlorophenylphosphonic acid, 4-chloro-3-nitro-phenylphosphonic acid, ß-styrylphosphonic acid and water-soluble copolymers of vinyl with acrylic acid and / or vinyl acetate.
• Polyvinylphosphonic acid is particularly preferred.
• the concentration of the phosphonic acid in the preservation solution is generally 0.05 to 10, preferably 0.1 to 5% by weight.
• water-soluble film-forming high-molecular organic compounds all of these are basically Substances suitable, commonly known as ingredients of K are used for lithographic printing plates onserv michsaten. Suitable examples are gum arabic, dextrins and polyvinyl alcohol.
• concentration of the high molecular weight compounds is generally between 4 and 40, preferably between 5 and 35% by weight.
• the preservation solution can be applied to the plate surface by hand rubbing or tamponing, by dipping in a bath, or in a processing device by rolling, spraying, or the like. It is then dried.
• Aluminum is generally used as the carrier material for the printing forms to be treated.
• the known and preferably used carrier materials with a refined surface come into consideration, for. B. mechanically, chemically or electrochemically roughened and optionally treated with alkali silicates, polymeric acids or other known agents aluminum.
• the solution is suitable for the treatment of printing plates with supports made of anodically oxidized aluminum, the oxide layer also being coated with the above-mentioned agents, e.g. B. silicates, can be pretreated.
• the printing image parts of the printing form can be produced in any known manner. As a rule, this is done by exposing a light-sensitive layer and developing with a developer solution.
• the picture Generation can also be done electrophotographically by charging, exposing, concreting and fixing a photoconductor layer.
• the nature of the carrier surface exposed during development and to be hydrophilized is of greater importance for the effectiveness of the treatment solution than the nature and the manner in which the printing layer is produced.
• Suitable positive-working light-sensitive layers can contain, as light-sensitive constituents, o-quinonediazides or combinations of photolytic acid generators and acid-cleavable acetal or orthocarboxylic acid compounds. Such layers preferably contain water-insoluble binders soluble in aqueous alkali, e.g. B. phenolic resins. Suitable layers are described in DE-PS 938 233, 1 195 166 and 26 10 842 and DE-OS 23 31 377, 27 42 631, 28 28 037, 27 18 254 and 29 28 636.
• negative working layers those based on diazonium salt condensation products, p-quinonediazides or photopolymerizable mixtures are preferably used. Suitable materials of this type are in the described the following publications: DE-PS 1 104 824, 1 134 093, 1 214 086, 20 27 467, DE-OS 20 24 244, 20 34 655, 27 39 774 and 28 22 887.
• Organic photoconductors are preferably used as photoconductors, for example those as described in DE-PS 11 20 875 or DE-AS 25 26 720.
• the binder in the photoconductor layer are preference -, those which are suitable insoluble and soluble in aqueous alkaline solutions in water. Copolymers containing carboxyl groups are particularly preferred. The production of suitable electrophotographic materials and their processing into printing forms is described in the publications mentioned above.
• the plate was charged with a corona to about -450 V and exposed imagewise in a repro camera with 8 autophot lamps of 500 W each for 25 seconds.
• tone-free prints were obtained, even if the background had been contaminated by fingerprints or otherwise before or after preservation.

Landscapes

• Printing Plates And Materials Therefor (AREA)
• Photosensitive Polymer And Photoresist Processing (AREA)
• Coloring (AREA)
• Printing Methods (AREA)
• Manufacture Or Reproduction Of Printing Formes (AREA)
• Shaping Of Tube Ends By Bending Or Straightening (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (3)

Family

ID=6094949

Family Applications (1)

Country Status (9)

Cited By (1)

Families Citing this family (14)

Family Cites Families (7)

• 1980
  • 1980-02-19 DE DE19803006094 patent/DE3006094A1/de not_active Withdrawn
• 1981
  • 1981-01-29 CA CA000369655A patent/CA1161702A/fr not_active Expired
  • 1981-02-10 EP EP81100910A patent/EP0034324B1/fr not_active Expired
  • 1981-02-10 DE DE8181100910T patent/DE3166236D1/de not_active Expired
  • 1981-02-10 AT AT81100910T patent/ATE9562T1/de not_active IP Right Cessation
  • 1981-02-17 ZA ZA00811043A patent/ZA811043B/xx unknown
  • 1981-02-18 JP JP2161781A patent/JPS56133193A/ja active Granted
  • 1981-02-18 US US06/235,541 patent/US4349391A/en not_active Expired - Lifetime
  • 1981-02-18 AU AU67397/81A patent/AU533379B2/en not_active Ceased
  • 1981-02-18 BR BR8100972A patent/BR8100972A/pt not_active IP Right Cessation

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