Classifications

• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
  • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
  • G03F7/004—Photosensitive materials
  • G03F7/06—Silver salts

Definitions

• the present invention relates to a hectographic method for forming hectographic copies of a hectographic master sheet.
• a photographic reproduction is produced on a light sensitive material, such as a silver halide emulsion which contains a finely and evenly distributed water insoluble dye stuff component which is preferably colorless or only slightly colored.
• a positive relief mirror image of the original is photographically produced under utilization of the Herschel effect.
• the projection of the original image may be carried out by reflex with a conventional photocopy device through the light permeable foil.
• a conventional photocopy device through the light permeable foil.
• the photo-sensitive emulsion is to be previously exposed to ultraviolet light and this pre-exposure is neutralized by carrying out the image transferring exposure with relatively long wave yellow light, thus utilizing the Herschel effect.
• the present invention contemplates in a method of forming a hectographic master sheet by photographic reproduction of an original image under utilization of the Herschel effect, the steps of forming a latent positive mirror image of said original image in a silver halide emulsion layer having distributed therethrough a substantially water insoluble and substantially non-coloring component of a chromogenic dye stuif adapted to react with a second component under formation of a printing ink, and developing said latent image with a hardening developer containing said second component and adapted to reduce silver halide so as to form a master sheet carrying a relief image including the thus formed printing ink so that when an imprint of said master sheet is made on a copy sheet, said image is transferred to said copy sheet.
• a component of a dye stuff which is formed by chromogenic development is incorporated in the gelatin layer of the master.
• an indophenol is used as such dye stufi component.
• the developing liquid for the master will then contain the second component of such dye stuif which is formed by chromogenic development, preferably a derivative of p-phenylene diamine, such as N,N-dimethyl-p-phenylene diamine, which will reduce the silver halide to silver and simultaneously will form by oxidation the printing ink, preferably an indophenol dye stuff.
• a developing liquid which also has tanning or hardening properties.
• Copies of the thus formed master can be produced by imprinting the master sheet onto copy sheets in the presence of a copying liquid which preferably reacts neutral and also preferably contains alcohol.
• the copying liquid is applied to the copy sheets so as to moisten the same prior to contact with the master.
• the hardening properties of the developing liquid can be achieved by incorporating in the same suitable hardening substances such as pyrocatechol, or by choosing a derivative of p-phenylene diamine which possesses chromogenic and hardening properties.
• phenols or substituted phenols such as alpha-naphthol or alpha-oxynaphthoic acid anilide in finely subdivided form may be worked into the gelatin layer as the dye stuff component thereof.
• dye stuff component compounds having an enolic hydroxyl group for instance pyrazolones and substituted pyrazolones, for instance 1-phenol-3- methyl-S-pyrazolone or anilides such as aceto-acetic acid anilide.
• Cleaning of the master from the expanded gelatin of the image-free portions may be carried out for instance by pressing against and again removing a sheet of absorbent paper from the master, or, the gelatin may be removed from the image-free portions of the master in a special cleaning bath.
• the printing ink will be formed only at the image forming portions of the master while the gelatin layer which corresponds to the image-free portions of the master will be incapable of developing the dye stuff or printing ink. Due to this fact it is even possible to use a developer, for instance a paraformaldehyde developer which causes hardening or hardening throughout of the entire gelatin layer, i.e. of the exposed as well as of the unexposed portions. In the latter case, the thus hardened gelatin of the image-free portions need not be removed by washing or cleaning.
• a developer for instance a paraformaldehyde developer which causes hardening or hardening throughout of the entire gelatin layer, i.e. of the exposed as well as of the unexposed portions.
• EXAMPLE I A photographic paper having a direct positive silver halide gelatin layer in which as dye stuff component alpha-naphthol (Formula I) has been incorporated, is exposed by reflex with light for relatively long wave lengths, for instance, with yellow light, while located underneath a positive image which is to be reproduced.
• Formula I The thus exposed layer is then developed With a hardening developer which contains as the second dye stuff component N,N-dimethyl-p-phenylene diamine (Formula Formula II C Ha Upon development, a blue printing ink consisting of an indophenol (Formula III) is formed which in the hardened image portions is incorporated in the positive mirror image.
• a hardening developer which contains as the second dye stuff component N,N-dimethyl-p-phenylene diamine (Formula Formula II C Ha
• a blue printing ink consisting of an indophenol (Formula III) is formed which in the hardened image portions is incorporated in the positive mirror image.
• EXAMPLE II A photographic paper having a direct positive silver halide gelatin layer, is exposed and developed as described in Example I. However, the dye stuff component which is incorporated in the gelatin layer is alpha-oxynaphthoic acid anilide (Formula IV).
• EXAMPLE III A photographic paper having a direct positive silver halide gelatin layer is placed underneath a positive transparent original image and is exposed through the same with yellow light.
• the gelatin layer of the paper contains as dye stuff component finely and evenly distributed l-phenyl-3-methyl-5-pyrazolone (Formula VI).
• purple dye stuff or printing ink namely an indophenol (Formula VIII) will be formed at the image forming portions of the emulsion layer of the master.
• a method of forming a hectographic master sheet by photographic reproduction of an orginal image under utilization of the Herschel eifect the steps of forming by exposure to long wave yellow light a latent positive mirror image of said original image in a silver halide emulsion layer which has been pre-exposed to ultraviolet light and which has having distributed therethrough a substance selected from the group consisting of phenols, alpha-naphthol, alpha-oxynaphthoic acid anilide, pyrazolones, and anilides as a substantially water insoluble and substantially non-coloring component of a chromogenic dye stuff adapted to react with a second component so as to form by such reaction a hectographic ink which is soluble in a copying liquid; and developing said latent image with a hardening developer containing N,N-dimeth yl-p-phenylenediamine as said second component and adapted to reduce silver halide so as to form a master sheet
• a hectographic printing master sheet wherein a mirror image of an original is formed by photographic exposure, and said master sheet has an emulsion layer which is pre-exposed to ultraviolet light, long wave yellow light is used to neutralize said exposure and a hectographic copy is made from said master sheet, the steps of photographically exposing to long wave length light, under a positive original, an emulsion layer which comprises gelatin, a silver halide and a waterinsoluble color-former capable of forming a hectographic dye upon chromogenous development, until an image is formed in said emulsion layer on said master sheet; treating said master sheet with a color-developer capable of reducing the exposed silver halide to silver, and capable of simultaneously forming said hectographic dye by reaction with said color-former, whereby said master sheet is developed and simultaneously said hectographic dye is formed on said master sheet; and removing said gelatin in the image-free portions.
• said colordeveloper is a developing liquid which comprises N,N- dimethyl-p-phenylenediamine.
• said colorformer additionally comprises a substance selected from the group consisting of phenols, alphanapthol and alphahydroxynaphthoic acid anilide.
• said developer is a liquid comprising a tanning substance whereby hardening occurs both at the non-exposed and at the exposed areas of said emulsion layer.
• said color-former comprises an enolic-hydroxyl-containing component which is a substance selected from the group consisting of pyrazolones and acetoacetic acid anilide.
• gelatin emulsion comprises a plurality of superposed layers and a plurality of diiferent color-formers are incorporated at least one in each of said layers, whereby a plurality of colors are formed in said image on said master sheet.

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• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Color Printing (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

Applications Claiming Priority (1)

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Family

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Family Applications (1)

Country Status (4)

Citations (11)

• 0
  • BE BE597054D patent/BE597054A/xx unknown
• 1959
  • 1959-12-11 DE DER26908A patent/DE1166794B/de active Pending
• 1960
  • 1960-10-21 GB GB36152/60A patent/GB925383A/en not_active Expired
  • 1960-12-09 US US74771A patent/US3241965A/en not_active Expired - Lifetime

Patent Citations (11)

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