US3432329A - Erasure-proof development of electrostatic images - Google Patents

Erasure-proof development of electrostatic images Download PDF

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Publication number
US3432329A
US3432329A US3432329DA US3432329A US 3432329 A US3432329 A US 3432329A US 3432329D A US3432329D A US 3432329DA US 3432329 A US3432329 A US 3432329A
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United States
Prior art keywords
ink
solution
developing
erasure
image
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English (en)
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Walter August Van Den Heuvel
Johan Eugeen Vanhaist
Jozef Leonard Van Engeland
Noel Jozef De Volder
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Gevaert Photo Producten NV
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Gevaert Photo Producten NV
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J13/00—Colloid chemistry, e.g. the production of colloidal materials or their solutions, not otherwise provided for; Making microcapsules or microballoons
    • B01J13/02—Making microcapsules or microballoons
    • B01J13/025—Applications of microcapsules not provided for in other subclasses
    • 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
    • B41M1/26—Printing on other surfaces than ordinary paper
    • B41M1/36—Printing on other surfaces than ordinary paper on pretreated paper, e.g. parchment, oiled paper, paper for registration purposes
    • 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
    • B41M5/124—Duplicating or marking methods; Sheet materials for use therein using pressure to make a masked colour visible, e.g. to make a coloured support visible, to create an opaque or transparent pattern, or to form colour by uniting colour-forming components
    • B41M5/132—Chemical colour-forming components; Additives or binders therefor
    • B41M5/155—Colour-developing components, e.g. acidic compounds; Additives or binders therefor; Layers containing such colour-developing components, additives or binders
    • 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
    • B41M5/124—Duplicating or marking methods; Sheet materials for use therein using pressure to make a masked colour visible, e.g. to make a coloured support visible, to create an opaque or transparent pattern, or to form colour by uniting colour-forming components
    • B41M5/165—Duplicating or marking methods; Sheet materials for use therein using pressure to make a masked colour visible, e.g. to make a coloured support visible, to create an opaque or transparent pattern, or to form colour by uniting colour-forming components characterised by the use of microcapsules; Special solvents for incorporating the ingredients
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G13/00—Electrographic processes using a charge pattern
    • G03G13/06—Developing
    • G03G13/10—Developing using a liquid developer, e.g. liquid suspension
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G15/00—Apparatus for electrographic processes using a charge pattern
    • G03G15/06—Apparatus for electrographic processes using a charge pattern for developing
    • G03G15/10—Apparatus for electrographic processes using a charge pattern for developing using a liquid developer
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G17/00—Electrographic processes using patterns other than charge patterns, e.g. an electric conductivity pattern; Processes involving a migration, e.g. photoelectrophoresis, photoelectrosolography; Processes involving a selective transfer, e.g. electrophoto-adhesive processes; Apparatus essentially involving a single such process
    • G03G17/02—Electrographic processes using patterns other than charge patterns, e.g. an electric conductivity pattern; Processes involving a migration, e.g. photoelectrophoresis, photoelectrosolography; Processes involving a selective transfer, e.g. electrophoto-adhesive processes; Apparatus essentially involving a single such process with electrolytic development
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G9/00—Developers
    • G03G9/06—Developers the developer being electrolytic
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G9/00—Developers
    • G03G9/08—Developers with toner particles
    • G03G9/12—Developers with toner particles in liquid developer mixtures
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G9/00—Developers
    • G03G9/08—Developers with toner particles
    • G03G9/12—Developers with toner particles in liquid developer mixtures
    • G03G9/122—Developers with toner particles in liquid developer mixtures characterised by the colouring agents
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/249921—Web or sheet containing structurally defined element or component
    • Y10T428/249994—Composite having a component wherein a constituent is liquid or is contained within preformed walls [e.g., impregnant-filled, previously void containing component, etc.]
    • Y10T428/249995—Constituent is in liquid form

Definitions

  • This invention relates to the erasure-proof development of electrostatic images.
  • an electrostatic latent image is developed with a developing liquid, the interfacial tension of which in respect of the surface of a solid material carrying an electrostatic charge pattern is influenced by the magnitude and the sense of the electrostatic field strength on this surface in such a way, that this surface is wetted selectively or differently in correspondence with the electrostatic charge pattern.
  • liquid developing compositions for use in erasure-proof liquid development of electrostatic charge patterns present in a recording element containing zinc oxide.
  • a recording element preferably a photoconductive zinc oxide containing electrophotographic element, which can provide zinc ions, an aqueous composition (solution or dispersion), which in addition to leuco compounds contains hexacyanoferrate (III) ions.
  • aqueous composition solution or dispersion
  • leuco compounds contains hexacyanoferrate (III) ions.
  • the said leuco compounds are quickly oxidized to dyes by hexacyanoferrate (III) ions, while these dyes are firmly adsorbed to the formed zinc hexacyanoferrates.
  • the developing liquids have preferably a pH of 7-2.
  • For acidifying preferably strong acids are used and acids forming soluble zinc salts in order to liberate very fast zinc ions from zinc oxide contained in the recording element.
  • the developing liquids, which are applied according to the present invention, as liquid ingredient preferably comprise only water, although they may be mixed with other liquids or may comprise thickening agents for adjusting the viscosity.
  • up to 10% of substances can be added to the developing liquid which slow down the drying rate of the ink such as glycerol, glycol, and sorbitol, and from 0 till 10% of binding agents which are soluble or dispersable in water such as gum arabic, carboxymethyl cellulose, casein, poly(vinyl pyrrolidone), poly(vinyl alcohol), poly(vinyl acetate), polyacrylate, polystyrene, waxes, silicates and colloidal silicic acid.
  • a zinc oxide containing recording material is mordanted by the treatment with hexacyanoferrate (III) ions and by the hexacyanoferrate (11) ions which are formed during the reduction with the leuco compounds. It was found that on the areas of the recording material, which was treated with a solution of hexacyanoferrate (III) ions and a leuco compound, further absorption of cationic dyes is still possible so as to resist erasure, so that the dye image built up with the dyes of the leuco compounds can be a given a different color by an after-treatment with cationic dyes.
  • compositions used in the present invention can be applied for instance in an electronic recording system described in the U.S. patent specification 2,577,894, wherein recording is carried out by means of a modulated air or gas current, which is charged with ink particles.
  • an aqueous developing liquid which contains potassium hexacyanoferrate (III) and one of the leuco compounds mentioned hereinbefore, is deposited image-wise according to one of these techniques onto a photoconductive material containing photoconductive zinc oxide in correspondance with an electrostatic charge pattern.
  • the oxidation reaction of the leuco compound with the potassium hex-acyanoferrate (III) proceeds very rapidly by the zinc ions already present or formed in situ, and the formed dye is firmly adsorbed image-wise to the formed zinc hexacyanoferrates.
  • the liquid image formed by means of a developing liquid as defined above can be covered selectively with an aqueous solution containing a cationic dye.
  • the first dye image formed by oxidation can be covered in an erasure-proof way by a cationic dye, whereby dye patterns are obtained in the most differing color tones and possessing a high color intensity.
  • a solution containing hexacyanoferrate (HI) ions can be applied first and thereupon a solution of a leuco compound occasionally together with a cationic dye, or inversely a solution of a leuco compound occasionally together with a cationic dye and thereupon a solution comprising hexacyanoferrate (III) ions.
  • multicolor images can be obtained onto one single recording material by successive development with solutions comprising difierent leuco compounds, and occasionally by the subsequent application of aqueous compositions containing cationic dyes possessing a color different from the color of the dyes formed by oxidation of the leuco compounds.
  • Example 1 ethanol 500 10% solution of monobutyl phosphate in ethanol 10 10% solution of succinic acid in dimethylformamide l 1% solution of fiuorescein (C.I. 45350) in ethanol
  • the photoconductive dispersion is applied to a paper support coated with aluminum foil in a ratio of 10 sq. :11. per liter by means of a roller coating system and dried.
  • the photoconductive layer obtained after drying is charged by a corona to -300 v./cm. by a tension of -7000 v. at the corona wires, and then exposed for 0.7 sec. through a diapositive with a watt lamp at a dis tance of 10 cm. Then the latent image is developed with a developing apparatus as schematically shown in FIG. 1.
  • the apparatus schematically shown in FIG. 1 comprises an ink roller 10 and a guiding roller 11.
  • the ink roller 10 is moistened with ink from the ink bath 12.
  • a doctor blade 13 regulates the amount of ink supplied.
  • the guiding roller 11 being in contact with the support 15 presses the recording material 14 with its photoconductive layer 16 against the ink roller 10.
  • the ink roller 10 is helically grooved.
  • the helical groove has a depth of 0.2 mm. and a top angle of 60.
  • the recording material 14 is led between the guiding roller 11 and the ink roller 10 at a speed of 2 m./min., and hereby the photoconductive layer containing the charge image comes into contact with a liquid meniscus supplied by the helically grooved ink roller 10.
  • the peripheral speed of the inking roller equals the travelling speed of the photoconductive layer.
  • the developing ink supplied in this way is prepared by mixing the following solutions A and B.
  • Potassium hexacyanoferrate (III) g 1 Water 100 A photoconductive layer as described in Example 1 is applied to a paper support with as resistivity 10 ohm. cm. After charging the layer as described in Example 1, an untransparent original is episcopically projected for 30 sec. onto the photoconductive layer.
  • This projection occurs by means of a camera with a Schneider Kreuznach Xenar 4.4 lense having a focal length of 21 cm. and set at the diaphragm aperture 5.6.
  • the light-source consists of two Sylvania Green 14 watt lamps.
  • the length of the light beam from the light source to an original is 84 cm.
  • Example 2 The development occurs as described in Example 1 but with a developing ink obtained by mixing a. 1% aqueous leuco crystal violet solution, acidified with hydrochloric acid up to pH 2, with a 1% aqueous potassium hexacyanoferrate (HI) solution.
  • a developing ink obtained by mixing a. 1% aqueous leuco crystal violet solution, acidified with hydrochloric acid up to pH 2, with a 1% aqueous potassium hexacyanoferrate (HI) solution.
  • Example 3 For the preparation of a photoconductive dispersion, the following products are mixed in a ball mill:
  • Plexigum P/ 25 (trade name for a 10% solution of a polyacrylate resin in acetone marketed by Rohn &
  • the dispersion obtained is applied by dip-coating to an aluminum sheet so that the quantity of zinc oxide amounts to 15 g./sq. m.
  • the guiding roller 11 is in this case an aluminum cylinder with a diameter of mm. and a length of 25 cm.
  • the ink roller 10 is made of chrome nickel steel 18/8 and has a diameter of 30 mm. and a length of 25 cm.
  • the surface of the ink roller 10 is helically grooved in such a way that the windings touch each other.
  • the groove is V-shaped with a width and depth of 0.5 mm.
  • the ink roller 10 freely rotates in the ink container 12 so that the groove is filled with ink. The ink'isretained in the groove by capillarity.
  • the photoconductive material 14 is led between the ink roller 10 and the guiding roll 11 at a speed of 3 m./min., the latent image facing the grooved ink roller 10.
  • a -10 v. tension is applied between the guiding roller and the ink roller.
  • the developing liquid is obtained by mixing a 1% aqueous solution of 4,4'-bis-dimethylamino-4"-sulphomethyl-triphenylmethane acidified with hydrochloric acid to pH 2, with a 1% aqueous solution of potassium hexacyanoferrate (III). A positive water proof green image is obtained.
  • Example 4 A photoconductive composition is prepared by mixing the following products:
  • This composition is applied to an 80 g./sq. m. barytacoated paper. After drying, the thickness of the photoconductive layer amounts to 25,11 Both exposure and development occur as schematically given in FIG. 2.
  • the photoconductive layer 16 of the recording material 18 being in contact with a negative original 19 is exposed for 1 min. with a 75 watt lamp 20 at a distance of 10 cm. and then developed with an apparatus schematically represented by FIG. 2(b).
  • the guiding roller 21 contacting the support 15 is connected with the positive pole and the smooth ink roller 22 with the negative pole of a 100 volt direct current source 23.
  • the smooth ink roller 22 is made from chromium nickel steel 18/8 and has a diameter of mm.
  • the exposed photoconductive material is led between the smooth ink roller 22 and the guiding roller 21 at a speed of 1 m./min.
  • the developing ink is obtained by mixing a 1% aqueous 4,4'-bis(dimethylamino)-4"-fiuorotriphenylmethane solution, acidified with hydrochloric acid to pH 2, with a 1% aqueous potassium hexacyanoferrate (III) solution.
  • Example 5 A photoconductive composition as prepared in Example l is applied to a 70 g./sq. m. glassine paper support in a ratio of 12 sq. m./litre. Both exposure and development as shown in FIG. 3 occur for 6 sec. in contact through a diapositive with a 75 watt lamp at a distance of 10 cm.
  • the ink roller 25 has a diameter of 39 mm, is helically grooved and made from chromium nickel steel 18/ 8.
  • the helical groove 26 has a depth of 0.2 mm. and a top angle of 60.
  • the guiding roller 27 has a diameter of 30 mm. and is made from aluminum.
  • the ink roller 25 has a speed of 100 t./min. and forms a liquid meniscus 28 against the photoconductive layer 16 to be developed. During development, the ink roller 25 is connected to the positive and the guiding roller 27 contacting the support 15 to the negative pole of a 200 v. direct current source 29.
  • the developing ink is obtained by mixing a 1% aqueous leuco indigo solution, acidified with hydrochloric acid to pH 3, with a 1% aqueous potassium hexacyanoferrate (III) solution.
  • a positive erasure-proof light blue image 30 is obtained.
  • Example 6 2 cc. of a 10% solution of monobutyl phosphate in ethanol and 30 g. of photoconductive zinc oxide powder are added to 100 cc. of a 10% solution of Curnar Resin P-25 (trade name for a coumaron-indene resin marketed by Barrett Chemicals, New York, N.Y., U.S.A.), in methylene chloride. The whole mixture is ground for 4 h. in a ball mill.
  • 4 cc. of a 5% solution of succinic acid in ethanol are added to the photoconductive dispersion.
  • the support to which the dispersion is applied in a ratio of 20 g./sq. m. is a 60 g./ sq. m. glassine paper.
  • Example 7 30 g. of Plexigum P-25 (trade name), g. of photoconductive zinc oxide and 6 cc. of a 10% solution of monobutyl phosphate in ethanol are added to 300 cc. of toluene. This mixture is thoroughly ground in a ball mill and then diluted with 200 cc. of toluene, whereupon 12 cc. of a 5% solution of succinic acid in ethanol are added whilst thoroughly mixing. The photoconductive dispersion is applied to a glassine paper support in a ratio of 20 g./ sq. m. and dried at 40 C.
  • the supply roller 25 is a cylinder made of chromium nickel steel l8/ 8 with a diameter of 25 mm. and a length of 25 cm.
  • the surface of this roller 25 is helically grooved.
  • the grooves 26 are V-shaped and have a depth of 0.5 mm. and a top angle of 60.
  • the developing liquid 31 is retained in the grooves 26 of the supply roller by capillarity.
  • the guiding roller 27 is an aluminum cylinder with a diameter of 15 mm. and a length of 25 cm.
  • a 400 volt direct current is applied between both rollers, by connecting the guiding roller 27 with the positive pole and the supply roller 25 with the negative pole of a direct current source 32.
  • a positive water-proof ink image is obtained.
  • a method of developing an electrostatic image on a recording element containing zinc oxide which comprises the steps of selectively applying to said image a developing liquid which is an aqueous developing composition consisting essentially of hexacyanoferrate (III) ions, a leuco compound of a cationic dye, water and a compound to maintain the pH of the developing composition at 7 or below, the amount of said leuco compound being suflicient to produce a visible coloration when oxidized to dye form and the amount of said hexacyanoferrate (III) ions being sufiicient to oxidize said leuco compound to dye form.
  • a developing liquid which is an aqueous developing composition consisting essentially of hexacyanoferrate (III) ions, a leuco compound of a cationic dye, water and a compound to maintain the pH of the developing composition at 7 or below, the amount of said leuco compound being suflicient to produce a visible coloration when oxidized to dye form and the amount of said
  • said developing composition contains about 0.52% of a water-soluble salt of hexacyanoferrate (III) and about 0.52% of said leuco compound.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Organic Chemistry (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Electrochemistry (AREA)
  • Molecular Biology (AREA)
  • Dispersion Chemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Color Printing (AREA)
  • Liquid Developers In Electrophotography (AREA)
  • Paper (AREA)
  • Photoreceptors In Electrophotography (AREA)
US3432329D 1963-05-17 1964-05-18 Erasure-proof development of electrostatic images Expired - Lifetime US3432329A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
NL292921 1963-05-17
GB5508168A GB1293133A (en) 1963-05-17 1968-11-20 Pressure-activatable image formation

Publications (1)

Publication Number Publication Date
US3432329A true US3432329A (en) 1969-03-11

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Application Number Title Priority Date Filing Date
US3432329D Expired - Lifetime US3432329A (en) 1963-05-17 1964-05-18 Erasure-proof development of electrostatic images
US3536517D Expired - Lifetime US3536517A (en) 1963-05-17 1968-12-03 Pressure recording process

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Application Number Title Priority Date Filing Date
US3536517D Expired - Lifetime US3536517A (en) 1963-05-17 1968-12-03 Pressure recording process

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US (2) US3432329A (ja)
JP (1) JPS494483B1 (ja)
BE (2) BE648063A (ja)
CH (1) CH442015A (ja)
DE (2) DE1472961A1 (ja)
FR (1) FR2023724A1 (ja)
GB (2) GB1032264A (ja)
NL (1) NL292921A (ja)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2131601A5 (ja) * 1971-03-24 1972-11-10 Ricoh Kk
US3798049A (en) * 1971-04-09 1974-03-19 H Kosche Method for the development of latent electrostatic images
US3909433A (en) * 1972-07-12 1975-09-30 Agfa Gevaert Nv Liquid electrophotographic developing compositions

Families Citing this family (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1325220A (en) * 1970-10-07 1973-08-01 Fuji Photo Film Co Ltd Colour-forming composition
US3873340A (en) * 1972-07-27 1975-03-25 Hodogaya Chemical Co Ltd Pressure-sensitive copying paper containing phenoxazine compounds
GB1465669A (en) * 1972-12-28 1977-02-23 Agfa Gevaert Pressure sensitive recording materials and pressure-recording procews
GB1433165A (en) * 1973-09-13 1976-04-22 Wiggins Teape Ltd Coated
GB1469481A (en) * 1974-02-01 1977-04-06 Ciba Geigy Ag Pressure-sensitive copying material
US4398753A (en) * 1980-12-26 1983-08-16 Mitsui Toatsu Chemicals, Incorporated Pressure sensitive recording unit
DE3312654C1 (de) * 1983-04-08 1984-06-20 Heinr. Meier Eisengießerei, 4993 Rahden Boden- oder Deckenablauf
DE4105066C2 (de) * 1991-02-19 1994-02-17 Ulm Edelstahl Tech Geruchverschluß für einen Entwässerungsgully
US20150175880A1 (en) * 2013-12-20 2015-06-25 Schlumberger Technology Corporation Method of viscosity reduction in the presence of fully coordinated compounds

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Publication number Priority date Publication date Assignee Title
US3001872A (en) * 1957-03-18 1961-09-26 Xerox Corp Preparing planographic plates and solution therefor
US3080251A (en) * 1958-03-13 1963-03-05 Xerox Corp Method of xerographic development
US3245381A (en) * 1961-04-19 1966-04-12 Agfa Ag Developing apparatus
US3272644A (en) * 1963-07-31 1966-09-13 Dennison Mfg Co Development of latent electrostatic images with crystalline toners
US3285741A (en) * 1961-04-19 1966-11-15 Agfa Gevaert Nv Process for developing electrostatic latent images
US3309990A (en) * 1961-01-25 1967-03-21 Azoplate Corp Process for the preparation of printing plates

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US2215196A (en) * 1936-09-23 1940-09-17 Gen Aniline & Film Corp Process of producing color on textile materials
BE480326A (ja) * 1944-01-31
US2548365A (en) * 1948-07-13 1951-04-10 Ncr Co Process for making pressure sensitive record materials
NL76787C (ja) * 1951-08-24 1900-01-01
US2800457A (en) * 1953-06-30 1957-07-23 Ncr Co Oil-containing microscopic capsules and method of making them
US2755203A (en) * 1954-02-03 1956-07-17 Du Pont Process of converting a polyamino-triarylmethane dye coating on a base from a stabilized leuco form to a colored form
US2935938A (en) * 1956-04-17 1960-05-10 Eugene Lefebure Methods of copy reproduction

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3001872A (en) * 1957-03-18 1961-09-26 Xerox Corp Preparing planographic plates and solution therefor
US3080251A (en) * 1958-03-13 1963-03-05 Xerox Corp Method of xerographic development
US3309990A (en) * 1961-01-25 1967-03-21 Azoplate Corp Process for the preparation of printing plates
US3245381A (en) * 1961-04-19 1966-04-12 Agfa Ag Developing apparatus
US3285741A (en) * 1961-04-19 1966-11-15 Agfa Gevaert Nv Process for developing electrostatic latent images
US3272644A (en) * 1963-07-31 1966-09-13 Dennison Mfg Co Development of latent electrostatic images with crystalline toners

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2131601A5 (ja) * 1971-03-24 1972-11-10 Ricoh Kk
US3798049A (en) * 1971-04-09 1974-03-19 H Kosche Method for the development of latent electrostatic images
US3909433A (en) * 1972-07-12 1975-09-30 Agfa Gevaert Nv Liquid electrophotographic developing compositions

Also Published As

Publication number Publication date
GB1032264A (en) 1966-06-08
DE1958096A1 (de) 1970-06-11
NL292921A (ja) 1900-01-01
GB1293133A (en) 1972-10-18
BE741955A (ja) 1970-05-20
JPS494483B1 (ja) 1974-02-01
US3536517A (en) 1970-10-27
DE1472961A1 (de) 1969-04-30
BE648063A (ja) 1964-11-19
CH442015A (fr) 1967-08-15
FR2023724A1 (ja) 1970-08-21

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