Classifications

• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03C—PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES; PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY
  • G03C1/00—Photosensitive materials
  • G03C1/494—Silver salt compositions other than silver halide emulsions; Photothermographic systems ; Thermographic systems using noble metal compounds
  • G03C1/498—Photothermographic systems, e.g. dry silver
  • G03C1/4989—Photothermographic systems, e.g. dry silver characterised by a thermal imaging step, with or without exposure to light, e.g. with a thermal head, using a laser
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
  • B41M5/00—Duplicating or marking methods; Sheet materials for use therein
  • B41M5/26—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used
  • B41M5/30—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used using chemical colour formers
  • B41M5/32—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used using chemical colour formers one component being a heavy metal compound, e.g. lead or iron

Definitions

• thermographic reproduction One well-known for copying typewritten ofiice correspondence and other graphic originals having difierentially radiation-absorptive image and background areas is known as thermographic reproduction. It involves the brief irradiation of the original, while sensitive copy-sheet, with high-intensity radiation. Preferential absorption of the radiation in the absorptive image areas then results in localized heating of the copy-sheet, producing a visible direct copy of the original. The background areas of the copy-sheet remain heat-sensitive.
• Another commercial 'oifice copying system requires preliminary exposure of a photosensitive sheet material to actinic radiation in a pattern determined by an original having radiation-transmissive background areas. Irradiated areas are thereby rendered non-reactive. The unexposed image areas may in some instances be rendered visible by heating, but for images of effective color density the sheet mustbe treated with a further reagent or activator in liquid or vapor form.
• Apparatus for carrying out the required sequence of operations is available under the designation Copy-Flex Model 100 copying machine. In this apparatus the composite of copy-sheet and transparency is passed over a rotating glass cylinder containing a mercury vapor lamp.
• Heat-sensitive copy-sheets have been described in which the visible change produced on localized brief heating is caused to occur by the inter-reaction ofa metal'saltand an organic chelating agent. The reaction produces a strongly colored permanent image. As previously described, however, these copy-sheets have been found to remain visibly heat-sensitive after, exposure to actinic radiation at speed in the Copy-Flex copying machine.
• the present invention provides a heat-sensitive copysheet having a visibly heat-sensitive layer containing, in physically distinct and chemically inter-reactive relationship, a metal salt and an organic chelating agent capable of reacting together, in the thermographic copying process or on momentarily heating the sheet to a conversion temperature in the range of about 90 C. to about 150 C., with the formation of a visibly distinct reaction product, the reactants being rendered incapable of undergoing such reaction on exposure to actinic radiation as provided in the Copy-Flex copying machine.
• the invention therefore makes possible the preparation of permanent, heatstable, high image density reproductions of graphic originals by procedures involving only irradiation and without any necessity of treatment with solutions, fumes, vapors, powders or other adjuvants.
• the composite of copy-sheet and original is first briefly irradiated with intense radiation rich in infrared and in accordance with known thermographic copying procedures.
• the thus imaged copy-sheet is next passed through the Copy-Flex copying machine under maximum exposure to the nearultraviolet radiation from the mer- 3,094,620 Ce Patented June 18, '1963 2 cury vapor arc.
• the resulting copy is stable against further heating to conversion temperature at the undarkened background areas.
• Copies may alternatively be prepared by first exposing the copy-sheet to the near-ultraviolet through a transparency, for example a ribbon or carbon copy of a typeand commercially important method in heat-conductive contact with a heatbacking,
• Dithiooxamide is known to be reactive with metal salts such as nickel stearate in the tom of heat-sensitive copy-sheets; but such products are found to remain heatsensitive under exposureto near-ultraviolet as just described.
• substituted dithiooxarnide such as N,N'-bis furfuryl dithioox-amide are equally elfectively, reactive with nickel stearate in copy-sheet formulations at conversion temperatures, while at the same time making possible the complete desensitization of the copy-sheet against such reaction by a single pass through the Copy-Flex machine.
• the substituted dithiooxamide and metal salt may be intimately dispersed in a thin film of a resinous or polymeric film-forming binder, either in self-sustaining film form or as a coating on a paper, film or other paper-like providing a unitary heat-sensitive copy-sheet in a single coating and drying operation.
• the two reactants may separately be dispersed or dissolved together with appropriate binders, and applied to a paper-like backing in separate coatings withintermediate drying, or to In the latter case the two sheets when held in face-to-face contact permit interfaci-al reaction at conversion temperature.
• the relative amounts of the two reactants are not critical, particularly in structures wherein the image-forming reaction occurs at an interface, the only requirement being that sutlicient of each reactant be present to ensure a readily visible change on reaction. It is desirable to employ a minimum amount of the substituted dithiooxamide and to maintain'this material in position for maximum exposure to the actinic radiation.
• Various additives are useful in providing copy-sheets of improved appearance, handling characteristics, or other properties. Pigments, fillers, plasticizers, dyes, waxes, resins and other additives may be incorporated. H I Thefollowing specific examples will further illustrate but not limit the invention. Proportions are given in parts by weight.
• the image areas are equally readily developed by replacing the transparency with a sheet of radiation-absorbent black paper prior to irradiating the composite with infra-red, or by placing the copy-sheet in contact with a heated metal platen or roller or in an oven heated to about 150 C.
• N,N'-bis fu-rfuryl dithiooxamide and nickel stearate as the reactant materials, a purple image color is obtained.
• Nickel stearate with N,N'-bis carboxyamyl dithiooxarnide provides a pink image.
• Other salts of nickel, such for example as nickel behenate, produce similar results. Salts of cobalt and copper are also useful.
• Other non-inventive variations will be apparent in view of the foregoing disclosures.
• a heat-sensitive copysheet capable of undergoing permanent visible change on being momentarily heated to a conversion temperature within the range of about 90 C. to about 150 C. and of becoming insensitive to said heating on moderate exposure .to near-ultraviolet radiation, said copy-sheet including a visibly heat-sensilive layer containing, in physically distinct and chemically inter-reactive relationship, chemically inter-reactant consisting essentially of nickel stearate and N,N-bis furfuryl dithiooxamide.
• a unitary heat-sensitive copy-sheet capable of undergoing permanent visible change on being momentarily heated to a conversion temperature within the range of about 90 C. to about 150 C. and of becoming inseni sitive to said heating on moderate exposure to near-ultraviolet radiation, said copy-sheet comprising a thin paperlike backing and a coating comprising a film-forming binder and, in physically distinct and chemically interreactive relationship, chemically inter-reactant components consisting essentially of nickel stearate and N,N'-'
• Method of copying comprising placing in surface contact and in position for irradiation a graphic original having ditierentially inf-rared absorptive image and back- 7 ground areas and a heat-sensitive copyisheet having a visibly heat-sensitive layer containing nickel stearate and N,N-bis furfiuryl dithiooxamide in physically distinct and chemically inter-reactive relationship, momentarily irradiating said graphic original with intense radiation rich in infra-red for causing visible inter-reaction in said i the near-ultraviolet wavelength region and in localized background-defining areas sufiicient to render said areas selectively insensitive to heat, and then heating at least the image-defining areas of said layer to provide a visible image.
• a radiation-desensitizable intermediate sheet product suitable for use in the reproduction of a graphic original by a process involving heating said sheet product, while in face-to-face contact with a separate receptor sheet consisting essentially of a paper-like backing and a surface layer of nickel stearate, at areas corresponding to image-forming areas of said original; the said intermediate sheet product consisting essentially of a paperlike backing and a surface layer of N,N'-bis furfuryl dithiooxamide.

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• Physics & Mathematics (AREA)
• Optics & Photonics (AREA)
• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• General Physics & Mathematics (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Heat Sensitive Colour Forming Recording (AREA)
• Non-Silver Salt Photosensitive Materials And Non-Silver Salt Photography (AREA)

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Citations (6)

Family Cites Families (1)

• 0
  • NL NL273128D patent/NL273128A/xx unknown
  • BE BE612242D patent/BE612242A/xx unknown
• 1961
  • 1961-01-03 US US79991A patent/US3094620A/en not_active Expired - Lifetime
  • 1961-01-03 US US79990A patent/US3094619A/en not_active Expired - Lifetime
  • 1961-12-30 SE SE13164/61A patent/SE313248B/xx unknown
• 1962
  • 1962-01-02 DE DEM51374A patent/DE1200846B/de active Pending
  • 1962-01-02 ES ES0273372A patent/ES273372A1/es not_active Expired
  • 1962-01-03 GB GB10700/65A patent/GB997362A/en not_active Expired
  • 1962-01-03 GB GB300/62A patent/GB997361A/en not_active Expired
  • 1962-01-03 FR FR883772A patent/FR1311591A/fr not_active Expired
  • 1962-01-03 CH CH5362A patent/CH419198A/de unknown
  • 1962-01-03 FI FI0008/62A patent/FI43136B/fi active

Patent Citations (6)

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