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
  • G03G9/135—Developers with toner particles in liquid developer mixtures characterised by stabiliser or charge-controlling agents
  • G03G9/1355—Ionic, organic compounds

Definitions

• the copying material for use in electrophotography is generally manufactured by forming a photoconductive layer on the surface of a support sheet or base, such as a metallic plate or paper whose back has been processed for conductivity, by means of coating said surface with a dispersion prepared through dispersing fine particles of some photoconductive substance, for instance, zinc oxide powder, in an organic solution of resinous binder, and drying the thus coated surface.
• a dispersion prepared through dispersing fine particles of some photoconductive substance for instance, zinc oxide powder
• some photoconductive substance for instance, zinc oxide powder
• the cause of said stained texture has been analyzed as follows. That is, inasmuch as the copying of an electrophotograph is generally effected by forming the image using a toner contained in the developer, said toner adsorbing electrostatically onto the copying material in proportion to the density of electric charge impressed on the photoconductive layer of said copying material, to wit, the highness of potential (or strictly speaking, the intensity of electric field), a photoconductive layer is required to be so charged as to have a uniform potential 3,681,243 Patented Aug. 1, 1972 when imparted an electrostatic photosensitivity by means of impressing an electrostatic charge thereon.
• the object of the present invention is to provide a liquid developer for use in electrophotography, said developer precluding the possibility of bringing about a stained texture in case of developing an electrophotographic copying material which has essentially such a defect as set forth above.
• a liquid developer for electrophotography contains a carrier liquid wherein a toner consisting of pigment and polarity-controlling resin has been dispersed, and further contains at least one member selected from the group consisting of such substances as expressed by the following general Formulas a through j, Dekalin, azobenzene, camphor, citral and styrene monomer.
• R represents a member selected from the group consisting of alkyl radicals (C H having 12 to 16 carbon atoms, and Me represents a member selected from the group consisting of Na and K.
• R R and R each represents one radical selected from the group consisting of H and alkyl radicals (C H t having 2 to 17 carbon atoms.
• an electrophotographic copying material having an electrostatic latent image formed thereon is dipped in a liquid developer wherein metal-dialkyldithiophosphate has been dissolved.
• molecules of said metal-dialkyl-dithiophosphate are influenced by the electric field and cause polarization as follows:
• any of phosphates such as disodiummonolauryl-phosphate (general Formula b), sodiumdilauryl-phosphate (general Formula 0) and triethylphosphate (general Formula (1), sulfate such as sodiumlauryl-sulfate (general Formula e), alcohols (general Formula f) such as nonyl alcohol, isopropyl alcohol, ,3, Naphthal and cetyl alcohol, monocarboxylic acids (general Formula g) such as lauric acid, myristic acid and palmitic acid, phthalate (general Formula h) such as butylphthalate, amines (general Formula i) such as triethylamine and stearyl amine, aldehyde (general Formula i) such as n-butylaldeh
• phosphates such as disodiummonolauryl-phosphate (general Formula b), sodiumdilauryl-phosphate (general Formula 0) and triethylphosphate (general Formula (1), s
• the developer of the present invention is obtained by means of kneading at least one of the foregoing substances with pigment, one or more than two resins contributable to imparting polar-controllability, dispersibility and fixability, and a small quantity of organic solvent, and subsequently dispersing the thus kneaded mixture in a carrier liquid (viz. paraflinic hydrocarbon or isoparaflinic hydrocarbon having a electric resistance of more than Q-cm. and a dielectric constant of less than 3).
• a carrier liquid viz. paraflinic hydrocarbon or isoparaflinic hydrocarbon having a electric resistance of more than Q-cm. and a dielectric constant of less than 3
• the alternative to said means is to add at least one of the aforesaid substances to either a concentrated liquid developer (prior to dispersion in a carrier liquid) put on the market or a liquid developer for immediate use as available also in the market and mix them well.
• the suitable quantity of said substance to be employed or the content in the developer in this occasion is in the range of 0.001- 0.1 part by weight per 1 part by weight of pigment of a toner contained in the developer.
• the quantity of phosphates as expressed by general Formulas b, c and d and the quantity of sulfate as expressed by general Formula e for adding to the developer are sufiicient in said range for the sake of effecting a satisfactory result, but as for other substances than the foregoing, the optimum quantity to be added is in the range of 0.01-0.1 part by weight for dithiophosphates as expressed by general Formula a, 0.01-0.05 part by weight for phthalate, 0.001-0.005 part by weight for alcohols, 0.01-0.l part by weight for carboxylic acid, 0.001-0.005 part by weight for amine, .00l-0.01 part by weight for Dekalin, 0.01-0.05 part by weight for azobenzene, 0.05- 0.1 part by weight for camphor,
• the so-called stained texture incident to development can be almost completely eliminated and, as a result, formation of a fully clear image can be expected.
• the developer of the present invention has such an advantage that, despite the concentration of image brought about thereby is quite evenly matched with that developed with conventional developers, the resultant image is visually more highly concentrated than the one in the prior art because of the absence of stained texture.
• Example 1 A mixture having a composition consisting of was thoroughly mixed for 16 hours by means of a ball mill, and subsequently 5 g. of thus treated mixture was dispersed in 1,000 cc. of a carrier liquid (a liquid hydrocarbon manufactured by ESSO Standard Sekiyu Co. and having the trade name Naphtha No. 6), whereby was obtained a liquid developer for use in electrophotography, said developer containing pigment particles negatively charged. Further, for the sake of comparison of efficiency, another liquid developer for use in said comparison was prepared by similarly dispersing 5 g. of a mixture having the same composition as above but with no metal-dialkyldithiophosphate.
• a carrier liquid a liquid hydrocarbon manufactured by ESSO Standard Sekiyu Co. and having the trade name Naphtha No. 6
• each value of the concentration in the foregoing Table 1 was measured through the relative measurement method, wherein the printing was conducted by employing a 2 mm.-square discontinuous gray scale as the original to avoid the edge effect peculiar to electrophotography and the maximum concentration of the print was measured by comparing it with one having a known concentration.
• Example 2 A mixture having a composition consisting of- Carbon black Polar-controlling resin: Nikanol HP- 30 Resin contributing to dispersibility: Plexol #966 (an acrylic copolymer resin manufactured by Rohm & Haas Co.)
• Example 3 A mixture having a composition consisting of 5%-toluene solution of metal-dialkyl-dithiophosphate (as expressed by general formula wherein both R; and R are isobutyl radicals, both R and R are lauryl radicals, and Me is calcium) 10 was treated in the same way as Example 1, whereby was obtained a liquid developer for electrophotography.
• a developer for use in comparison was prepared by means of dispersing about 5 g. of the mixture having the aforesaid composition in a carrier liquid.
• Each of the above developers was then treated in the same way as Example 1 and employed for developing the electrophotographic copying material carrying the electrostatic latent image, and subsequently measurement was conducted of the concentration of the resultant images as well as the concentration in the texture area.
• Nikko Chemicals Inc. with the trade name N ikkol-SLS). 8 K-lauryl sulfate (5 toluene solution; a manufacture of Nikko 1.32 0. 11
• Example 4 was combined with various additives respectively, and subsequently about 5 g. each of the respective mixtures thus prepared was dispersed in the same carrier liquid as Example 1, whereby were prepared 43 kinds of liquid to said Table 2just one additive substance effective in preventing the stained texture, it is definite that, in so far as the quantity employed is in the range of 0.00 1-0.1 part by weight per 1 part by weight of the pigment contained in a developer, the effect to be brought about in case two substances or more are employed is equivalent to that in case just one substance is employed.
• a liquid developer for electrophotography comprising l) a carrier liquid consisting of a liquid hydrocarbon having an electric resistance of more than 10 Q cm. and a dielectric constant of less than 3; (2) a toner dispersed in said carrier liquid, said toner being comprised of carbon black particles and a coating layer coated on said particles, said coating layer consisting essentially of a resin selected from the group consisting of phenol modified xylene resin and acrylic resins; and (3) a stain texturepreventing agent dissolved in said carrier liquid, said agent being selected from the group consisting of compounds expressed by Formula a R; O S S Rm in a quantity in the range of 0.01 to 0.1 part by weight per one part by weight of said carbon black, and wherein each of R R R and R is a monovalent radical selected from the group consisting of alkyl radicals having 3 to 18 carbon atoms and aralkyl radicals combined with a side-chain having 3 to 18 carbon atoms, and Me; is a divalent metal radical; compounds expressed by Formula b R (

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• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Liquid Developers In Electrophotography (AREA)

Applications Claiming Priority (2)

Publications (1)

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Family Applications (1)

Country Status (4)

Cited By (10)

Families Citing this family (5)

• 1969
  • 1969-05-22 US US827049A patent/US3681243A/en not_active Expired - Lifetime
  • 1969-05-27 DE DE1926918A patent/DE1926918C3/de not_active Expired
  • 1969-05-28 GB GB26995/69A patent/GB1276363A/en not_active Expired
  • 1969-05-30 FR FR6917916A patent/FR2009688A1/fr not_active Withdrawn

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