Classifications

• • 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
  • G03G9/135—Developers with toner particles in liquid developer mixtures characterised by stabiliser or charge-controlling agents
• • 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
• • 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
  • G03G9/13—Developers with toner particles in liquid developer mixtures characterised by polymer components
  • G03G9/131—Developers with toner particles in liquid developer mixtures characterised by polymer components obtained by reactions only involving carbon-to-carbon unsaturated bonds
• • 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
  • G03G9/135—Developers with toner particles in liquid developer mixtures characterised by stabiliser or charge-controlling agents
  • G03G9/1355—Ionic, organic compounds
• • 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
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S430/00—Radiation imagery chemistry: process, composition, or product thereof
  • Y10S430/001—Electric or magnetic imagery, e.g., xerography, electrography, magnetography, etc. Process, composition, or product
  • Y10S430/105—Polymer in developer

Definitions

• a liquid developer for electrophotography prepared by adding, to a pigment, an electric charge polarity controlling agent consisting of a synthetic resin and having a novel chemical'structure, kneading themixture, and dispersi'n'g the'kneaded mixture either independently or together with a surface active agent in acarrier liquid consisting of a hydrocarbon having a high electric resistance (a specific resistance of 10 0 cm. or more) and a low dielectric constant of 3 or less.
• liquid developers of the prior art had the shortcoming that their prolonged use or storage led to a deterioration of the dispersing ability of the toner, and this, in turn, caused the fine particles of pigment to agglomerate and precipitate in the carrier liquid, resulting in a marked loss of their developing ability and also a marked loss of the distinct electric charge polarity added to the fine particles of pigment.
• rosin or asphalt was used in combination with particles of such pigment as carbon black which, b nature, never exhibits a distinct electric charge polarity, it was difficult to control the electric charge polarity of such particles, and the control of the polarity of the electric charge of these particles required an additional use of an auxiliary organic pigment capable of making the polarity of the impressed electric charge distinct.
• the object of the present invention to provide a liquid developer for electrophotography which does not deteriorate during prolonged storage and repeated use.
• the developing agent of the present invention is prepared by dispersing an inorganic or organic pigment, such as carbon black, aniline black, prussian blue, phthalocyanine blue, red oxide and cadmium yellow, in an electric charge polarity controlling agent consisting of a copolymer expressed by the below-mentioned general formula, and dispersing the resulting mixture in a carrier liquid consisting of a paraffinic or isoparaflinic hydrocarbon having a high electric resistance and a low dielectric constant:
• an inorganic or organic pigment such as carbon black, aniline black, prussian blue, phthalocyanine blue, red oxide and cadmium yellow
• R and R are selected from the group consisting of hydrogen and alkyl group having 1 to 4 carbon atoms;
• L represents an atomic group capable of chemically bonding to the chain of a polymer and is selected from the group consisting of o 0 II II OC-, COO and i NHC X is selected from the oleophilic atomic group consisting of n 2n+1:
• copolymers expressed by said general formula can be obtained by the use of a known polymerizing process and, therefore, the description of such process is omitted.
• the long-chain alkyl group, aralkyl group or alkylene group is dominatingly responsible for the solubility of said copolymers in hydrocarbons constituting the carrier liquids.
• the copolymerization ratio of (a) to (b) may be 9 or less depending on the type of the atomic group such as R X and Y. With such a small ratio, however, the solubility of the copolymers in the carrier hydrocarbon liquids decreases, leading to the occurrence of undesirable agglomeration and deterioration of the pigment particles which are contained in the developers.
• an electric charge polarity controlling agent consisting of any of the aforesaid copolymers and having a specific functional radical Y introduced in its chemical structure enhances the adsorptivity of the molecules of such an electric charge polarity controlling agent to the pigment particles and also enhances the ability to disperse in the carrier liquid, of the concentrated toner which is produced by mixing pigments, controlling agents, and solvent.
• the electric charge polarity controlling agent which is provided according to the present invention has a substantially increased ability to control the polarity of the electric charge of such pigment particles as carbon black which is hard to control of its electric charge polarity. Therefore, this controlling agent does not require the use of any organic pigment as an auxiliary additive, whereas it was necessary to do so with the prior art.
• the liquid developer of the present invention which has been described above is such that the toner consisting of pigment particles and an electric charge polarity controlling agent and dispersed in a carrier liquid is negatively charged. It has been confirmed by the inventors that by the addition, to this developer, of a surface active substance which is miscible in said carrier liquid, the polarity of the electric charge of the developer particles is reversed.
• the preferred electric charge polarity reversers which are used in the present invention include naphthenic acid as well as metal salts of naphthenic acid with metals such as cobalt, manganese, cadmium, copper, iron, nickel, chromium, magnesium and zinc; palmitic acid, stearic acid and oleic acid and their mono-, diand tri-aluminum salts; and cationic and nonionic surface active agents.
• a developer having a distinctly positively charged toner in case the developer contains one or more of said electric charge polarity reversers in an amount of 0.001%-10% by weight of the total weight of the pigment particles of said toner.
• a liquid developer for electrophotography which is uniform in both quality and property, owing to the fact that all of its components are made with synthetic materials.
• the present invention has a further advantage that the electric charge polarity of the toner consisting of aforesaid pigment and synthetic resin and being contained in said developer can be easily reversed by the addition of a surface active substance.
• the developer of the present invention is extremely superior to those of the prior art with respect to life and developing ability including fixing ability.
• the present invention has a lot to contribute to the field of the electrophotographic industry.
• a concentrated developer was obtained, which is called a concentrated toner
• 2 parts by weight of this toner was diluted in 1000 parts by weight of an isoparafiinic hydrocarbon (Isopar H, a product of Esso Standard Oil Corporation), and as a result, a liquid developer for electrophotography having a negatively charged developer was obtained.
• This liquid developer was used in electrophotographic copying, and an excellently fixed print of the image was obtained.
• the developer remained stable for an extended period of time. Also, the print of the image was clear. It was noted that this developer was suitable for use in copying enlarged images from negative microfilms as well as ordinary negative films.
• Example 2 To 1 part by weight of aniline black were added 3 parts by weight of cetylacrylate-acrylonitrile copolymer (copolymerization ratio being 9.5: l) as an electric charge polarity controlling agent, and 7 parts by weight of mineral terpene, and they were thoroughly mixed and dispersed by the use of a ball mill. Thereafter, by processing the mixture in a manner similar to that described in Example 1, a liquid developer for electrophotography having a negatively charged toner was obtained. Electrophotographic copying was conducted by the use of this liquid developer, with a result that the print of the image was noted to be quite satisfactorily fixed. This print of the image was a highly well contrasted one. The developer exhibited a stable function for an extended period of time.
• Example 3 To 10 parts by weight of phthalocyanine blue were added 30 parts by weight of laurylmethacrylate-methacrylic acid copolymer (copolymerization ratio being 9.5 :1) as an electric charge polarity controlling agent, 0.5 part by weight of cobalt salt of naphthenic acid as an electric charge polarity reverser, and 60 parts by weight of mineral terpene, and they were thoroughly mixed by the use of a ball mill. 1 part by weight of this concentrated toner was diluted in 1000 parts by weight of an isoparaflinic hydrocarbon (Isopar H, a product of Esso Standard Oil Corporation), and a liquid developer for electrophotography having a positively charged toner was obtained. This developer was used in an electrophotographic copying, and the fixation of the print of the image Was noted to be excellent and the print of the image was highly well cont-rasted. The developer retained its stability for an extended period of time.
• laurylmethacrylate-methacrylic acid copolymer (copolymer
• Example 4 To 10 parts by weight of Mitsubishi Color Carbon No. 44 (a product of Mitsubishi Kasei K. K.) were added 40 parts by weight of cetylmethacrylate-methacrylic acid copolymer (copolymerization ratio being 9:1) as an electric charge polarity controlling agent, 0.1 part by Weight of copper salt of naphthenic-acid as an electric charge polarity reverser, and 50 parts by weight of mineral terpene, and they were thoroughly mixed by the use of a ball mill. 2 parts of this toner were diluted in 1000 parts by weight of an isoparaffinic hydrocarbon (Isopar H, a product of Esso Standard Oil Corporation), and a developer liquid for electrophotography having a positive charge was obtained.
• Isopar H isoparaffinic hydrocarbon
• Electrophotographic copying was conducted by the use of this developer, and it was noted that, although the fixation of the print of the image was satisfactory, the print of the image was less well contrasted than that obtained in Example 3. From this fact was noted that this developer was suitable for continuous tone copying.
• Example 1 To parts by weight of red oxide were added 50 parts by weight of laurylmethacrylate-dimethylaminoethylmethacrylate copolymer (copolymerization ratio being 9:1) as an electric charge polarity controlling agent, 005 part by weight of iron salt of naphthenic-acid as an electric charge polarity reverser, and 40 parts by weight of an isoparaffinic hydrocarbon (Isopar H, a product of Esso Standard Oil Corporation), and they were thoroughly mixed by the use of a ball mill.
• laurylmethacrylate-dimethylaminoethylmethacrylate copolymer (copolymerization ratio being 9:1)
• iron salt of naphthenic-acid As an electric charge polarity reverser
• Isopar H an isoparaffinic hydrocarbon
• a liquid developer for electrophotography comprising a carrier liquid consisting of a hydrocarbon having a high electrical resistivity of not less than 10 9 cm. and a low dielectric constant of not greater than 3, a negatively electrostatically charged toner dispersed in said carrier liquid, said toner consisting Substantially of fine particles of a pigment selected from the group consisting of carbon black, aniline black, prussian blue, phthalocyanine blue, red oxide and cadmium yellow, and a copolymer coated on the surface of said pigment particles, said 'copolymer being capable of imparting a negative electrostatic charge to said toner and consisting of a combination of a structural unit expressed by the below-mentioned formula (a) and a structural unit expressed by the belowmentioned formula (b):
• R represents a radical selected from the group consisting of hydrogen and alkyl radicals having 1 to 4 carbon atoms;
• L represents an atomic group capable of chemically bonding to the chain of said copolymer and is selected from the group consisting of and 0 ll NHC X is selected from the oleophilic atomic group consisting of C H (wherein 1427756) and (wherein 142712 6); and Y is selected from the functional atomic group consisting of COO(CH ),,N(R)
• liquid developer according to claim 1 wherein said liquid developer further contains at least one surface active substance selected from the group consisting of:
• an aluminum salt selected from the group consisting of monoaluminum palmitate, dialuminum palmitate, trialuminum palmitate, monoaluminum stearate, dialuminum stearate, trialuminum stearate, monoaluminum oleate, dialuminum oleate and trialuminum oleate, said surface active substances being capable of converting the negative charge of said toner to a positive charge.

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• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Liquid Developers In Electrophotography (AREA)

Applications Claiming Priority (1)

Publications (1)

Family

ID=13595467

Family Applications (1)

Country Status (3)

Cited By (20)

Families Citing this family (1)

• 1967
  • 1967-11-13 US US682568A patent/US3554946A/en not_active Expired - Lifetime
  • 1967-11-20 BE BE706743D patent/BE706743A/xx unknown
  • 1967-11-21 DE DE19671597860 patent/DE1597860B1/de not_active Withdrawn

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