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
  • B41C1/1066—Forme preparation for lithographic printing; Master sheets for transferring a lithographic image to the forme by spraying with powders, by using a nozzle, e.g. an ink jet system, by fusing a previously coated powder, e.g. with a laser

Definitions

• US-P- 5 312 654 discloses a method for making lithographic printing plates comprising: forming an image on a substrate having an ink absorbing layer and a hydrophilized layer between the substrate and absorbing layer by ink-jet printing using a photopolymerizable ink composition, and exposing it to an active light in the wavelength region for which said ink composition is sensitized to cure the image.
• the printing endurance of said printing plates is low.
• Japanese Kokai Publication 69244/1992 discloses a method for making printing plates comprising the steps of forming a printed image on a recording material subjected to a hydrophilic treatment by ink-jet printing using a hydrophobic composition containing photocurable components; and exposing the whole surface to an active light.
• the surface of the substrate to be used for the lithographic plate is usually subjected to various treatments such as a mechanical graining, an anodizing or a hydrophilic treatment to obtain good hydrophilic property and water retention property. Therefore, even the use of an ink composition having a very high surface tension results in a poor image on the surface of the substrate because of ink spreading and low printing endurance.
• Suitable hydrophilic binders for use in an image-forming layer in connection with this application are water soluble (co)polymers for example synthetic homo- or copolymers such as polyvinylalcohol, a poly(meth)acrylic acid, a poly(meth)acrylamide, a polyhydroxyethyl(meth)acrylate, a polyvinylmethylether or natural binders such as gelatin, a polysaccharide such as e.g. dextran, pullulan, cellulose, arabic gum, alginic acid, inuline or chemically modified inuline.
• water soluble (co)polymers for example synthetic homo- or copolymers such as polyvinylalcohol, a poly(meth)acrylic acid, a poly(meth)acrylamide, a polyhydroxyethyl(meth)acrylate, a polyvinylmethylether or natural binders such as gelatin, a polysaccharide such as e.g. dextran,
• the imaging element further preferably includes a compound capable of converting light to heat.
• Suitable compounds capable of converting light into heat are preferably infrared absorbing components although the wavelength of absorption is not of particular importance as long as the absorption of the compound used is in the wavelength range of the light source used for image-wise exposure.
• Particularly useful compounds are for example dyes and in particular infrared dyes and pigments and in particular infrared pigments such as carbon black, metal carbides, borides, nitrides, carbonitrides, bronze-structured oxides and oxides structurally related to the bronze family but lacking the A component e.g. WO2.9.
• the hydrophobic composition can be a hot melt composition.
• the hot melt composition used in the present invention is a solid hydrophobic composition that is melted in the ink jet printhead.
• a hot melt composition, also called a phase change composition consists of a hot melt ink carrier composition, and a dye.
• the phase change ink carrier may be a composition containing optionally a natural wax or a mixture of natural waxes or a mixture of (a) natural and (a) synthetic wax(es).
• the main requirement for the composition according to the invention is to be a meltable, jettable hydrophobic substance having appropriate physical characteristics, e.g. a phase change ink carrier.
• dyes and coloring agents are not required , but can help the operator to see the image on the plate.
• the phase change ink carrier composition comprises a tetra-amide and a mono-amide compound, a tackifier, a plasticizer, and a viscosity modifying agent.
• the preferred compositional ranges of this phase change ink carrier composition are as follows : from about 10 to 50 weight percent of a tetra-amide compound, from about 30 to 80 weight percent of a mono-amide compound, from about 0 to 25 weight percent of a tackifier, from about 0 to 25 weight percent of a plasticizer, and from about 0 to 10 weight percent of a viscosity modifying agent.
• phase change ink formed from the phase change ink carrier composition exhibits excellent physical properties. More details are given in EP-A 353 979 .
• the polymerizable compounds are the compounds characterized by having at least one ethylenically unsaturated double bound which is cured by radical addition polymerisation initialised by a polymerization initiator activated by addition of energy such as actinic light or heat.
• These compounds include mono- and polyunsaturated carboxylic acids esters such as acrylate esters of polyhydroxy compounds such as ethylene glycol, tetraethylene glycol, neopentylglycol, propylene glycol, 1,2-butanediol, trimethylolpropane, pentaerythritol and di-pentaerythritol and the like with the above-described unsaturated carboxylic acids, diglycidylester of phthalic acid and the like with the above-described unsaturated carboxylic acids.
• These photopolymerizable compounds are present in the photopolymerizable compositions according to the present invention in an amount of 20 to 99.9% by weight, preferably 25 to 99%
• the composition can comprise a latex of a hydrophobic organic particle in an aqueous medium.
• a latex is defined as a stable colloidal dispersion of a polymeric substance in an aqueous medium.
• the polymer particles are usually approximately spherical and of typical colloidal dimensions: particle diameters range from about 20 to 1000 nm.
• the dispersion medium is usually a dilute aqueous solution containing substances such as electrolytes, surfactants, hydrophilic polymers and initiator residues.
• the polymer latices are classified in various way.
• the printing plate of the present invention can also be used in the printing process as a seamless sleeve printing plate.
• This cylindrical printing plate has such a diameter that it can be slided on the print cylinder. More details on sleeves are given in "Grafisch Nieuws" ed. Keesing, 15, 1995, page 4 to 6.
• This layer was hardened for 12 hours at 67 °C and 50 % R.H. An imaging element was so obtained.

Landscapes

• Physics & Mathematics (AREA)
• Optics & Photonics (AREA)
• Engineering & Computer Science (AREA)
• Manufacturing & Machinery (AREA)
• Manufacture Or Reproduction Of Printing Formes (AREA)
• Printing Plates And Materials Therefor (AREA)
• Photosensitive Polymer And Photoresist Processing (AREA)
• Materials For Photolithography (AREA)

Priority Applications (4)

Applications Claiming Priority (1)

Publications (2)

Family

ID=8240332

Family Applications (1)

Country Status (3)

Families Citing this family (4)

Family Cites Families (1)

• 1999
  • 1999-06-21 DE DE1999613504 patent/DE69913504T2/de not_active Expired - Lifetime
  • 1999-06-21 EP EP19990201990 patent/EP1063086B1/en not_active Expired - Lifetime
• 2000
  • 2000-06-16 JP JP2000181423A patent/JP2001030457A/ja active Pending

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