Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
  • B41M3/00—Printing processes to produce particular kinds of printed work, e.g. patterns
  • B41M3/14—Security printing
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
  • B41M1/00—Inking and printing with a printer's forme
  • B41M1/12—Stencil printing; Silk-screen printing
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
  • B41M1/00—Inking and printing with a printer's forme
  • B41M1/22—Metallic printing; Printing with powdered inks
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
  • B41M7/00—After-treatment of prints, e.g. heating, irradiating, setting of the ink, protection of the printed stock
  • B41M7/0027—After-treatment of prints, e.g. heating, irradiating, setting of the ink, protection of the printed stock using protective coatings or layers by lamination or by fusion of the coatings or layers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B44—DECORATIVE ARTS
  • B44C—PRODUCING DECORATIVE EFFECTS; MOSAICS; TARSIA WORK; PAPERHANGING
  • B44C1/00—Processes, not specifically provided for elsewhere, for producing decorative surface effects
  • B44C1/04—Producing precipitations

Definitions

• ABSTRACT This method of manufacturing metal coated sheets, mainly gold-coated or gilded sheets, for making postage stamps, comprising depositing by the serigraphic process, on an absorbent sheet, a homogeneous composition of fine metal powder, binder and solvent, in several successive layers, with a drying step between successive applications, and fixing and polishing said layers by repeatedly passing the sheet through a polishing machine comprising a cylinder coated with very hard rubber and a cylinder of hardened steel, these cylinders being urged against each other by a pressure of the order of 300 to 500 psi.
• the present invention is concerned with improvements in the methods of producing by the silk-screen process sheets coated with precious metal such as gold, notably for manufacturing postage stamps and the like.
• stamps were also manufactured from golden sheets by using gold films deposited on a generally cellulose support, the thickness of these films being however of the order of a few Angstroms, but the quantity of gold contained in stamps of this character is extremely small, so that the process may be regarded more as the metal coating or metallization of a paper sheet constituting the stamp proper than forming a stamp on a golden sheet.
• Another known method consists in fixing the metal powder to its support by means of the serigraphic or silk-screen process.
• This process consists essentially in mixing the metal powder with a binder and a solvent, and subsequently apply the mix to the sheet through a silk (and mostly Nylon) screen or wire gauze stretched in a rigid frame.
• silk and mostly Nylon
• metal powder deposits formed either on flat-tint surfaces or on decorative patterns reproduced as resists on the silk-screen are obtained.
• this process is advantageous on account of its relative regularity, it is still objectionable on account of the powdering effect and therefore of the removal, by rubbing, of a certain amount of powder after the application. Moreover, the surfaces thus obtained are relatively dull.
• stamps made from golden sheets are intended to be embossed for setting in relief certain areas of the vignette (effigies or facial values, for instance), it is an essential requirement that the various treatments to be applied to the golden sheets shall not produce any distortion thereof, for such distortion would definitely prevent the necessary coincidence or matching of the subjects deposited on the golden sheet through a serigraphic process or another process with the subjects or patterns engraved on the tool means used for the embossing operation.
• a suitable support such as an adhesive-coated offset paper, which must have an absorption capacity sufficient to take at least one fraction of the binder coating the particles of gold powder, there is deposited through a serigraphic screen a printing paste consisting of a mixture of gold powder with a cellulose binder and a solvent. These ingredients must be metered with a great care in order to maintain the weight of deposited gold to a constant value.
• the printing takes place in several passes with a drying step between two successive passes, to permit a proper control of the weight of deposited gold particles. These successive passes are necessary for eliminating the abovementioned powdering effect, each successive layer causing the underlying layer to be safely fixed on the sheet surface.
• the golden sheet thus obtained is introduced into a polishing machine specially designed for this purpose.
• the golden sheet is passed between a very hard rubber cylinder and a carefully ground and polished hardened steel cylinder, both cylinders being urged against each other by using a constant hydraulic, pneumatic or mechanical pressure, so that the sheet eventually emerging from this machine is extremely glossy while having all the desired properties, without having undergone any distortion.
• the metal brightness is further improved by repeating this polishing operation.
• EXAMPLE For manufacturing a golden sheet intended for making postage stamps, there are used a printing paste consisting of a mixture of fine gold powder and a binder, dissolved in a cellulose solvent, and a serigraphic screen on which the resists corresponding to the ornamental designs or patterns of the stamps are reproduced.
• the screen receives several layers, and a drying step is reserved between successive applications, so that each deposit or coating of said composition on the support or carrier sheet disposed and adjusted under the screen is fixed by the next deposit or coating.
• a machine comprising positioning members on the serigraphic screen and means for depositing the composition, scraping off the excess as well as means for evaporating the solvent between successive applications, are provided.
• the sheet emerging from this machine which is coated with several regular and homogeneous layers of gold on a thickness of a few microns, has a full appearance and the last layer, even when dry, displays the above-mentioned powdering effect.
• the sheet is subsequently introduced one or preferably several times into a smoothing or polishing machine comprising a cylinder'lined with very hard rubber and a hardened steel cylinder, these two cylinders being urged towards each other under a strictly constant but adjustable pressure of the order of 300 to 500 psi.
• the sheet issuing from this machine meets all the above-defined requirements and can be subsequently subjected to the known embossing, pigmenting, printing and perforation operations.
• a method of manufacturing sheets of stamps comprising relief areas coated with gold powder which alternate with resist-printed areas, comprising depositing through a previously prepared serigraphic textile screen a mixture of very finely divided gold powder with a binder and a solvent on an offset paper sheet having a glue coated back, repeating this step according to the desired thickness of the gilded areas while allowing the coat to dry between at least two successive passes until a homogeneous metal layer adhering perfectly to the sheet areas to be gilded has been obtained, color-printing the other resist areas of the stamp and imparting the desired luster to the gilded areas by a calendering performed between a rubber-coated cylinder and a carefully ground and polished hardened steel cylinder, said cylinders being urged against each other by an adjustable and constant pressure.

Landscapes

• Printing Methods (AREA)
• Other Surface Treatments For Metallic Materials (AREA)
• Inks, Pencil-Leads, Or Crayons (AREA)
• Paper (AREA)
• Powder Metallurgy (AREA)
• Polishing Bodies And Polishing Tools (AREA)
• Chemically Coating (AREA)

Applications Claiming Priority (1)

Publications (1)

Family

ID=9101380

Family Applications (1)

Country Status (8)

Families Citing this family (2)

Citations (1)

• 1972
  • 1972-07-05 FR FR7224295A patent/FR2191475A5/fr not_active Expired
• 1973
  • 1973-06-26 CH CH927673A patent/CH576043A5/xx not_active IP Right Cessation
  • 1973-07-02 US US375864A patent/US3914474A/en not_active Expired - Lifetime
  • 1973-07-03 IT IT68974/73A patent/IT991653B/it active
  • 1973-07-03 ES ES416525A patent/ES416525A1/es not_active Expired
  • 1973-07-03 GB GB3175073A patent/GB1422921A/en not_active Expired
  • 1973-07-04 DE DE2334083A patent/DE2334083C3/de not_active Expired
  • 1973-07-05 JP JP7608373A patent/JPS5726958B2/ja not_active Expired

Patent Citations (1)

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