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
  • G03G9/13—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

Definitions

• the present invention relates to a liquid toner composition for use in electrostatic printing processes; more particularly, the present invention relates to a negatively charged liquid toner system comprising an electrically insulating carrier liquid, a pigment or coloring agent, a metallic soap and a polymer.
• an overall negative electrostatic charge is produced on a photoconductive surface, e.g. zinc oxide dispersed in a binder. This is followed by an imagewise discharge through light exposure so as to leave a negative charge in the unexposed areas. It is at this point that the liquid toner composition is applied.
• the particles of the toner composition comprising the pigment or coloring agent are directed to the negatively charged areas of the latent image. In the case of the electrostatic reproduction process briefly described above, this results in the production of an identical reproduction of the original.
• toner e.g., carbon black or similar pigment or coloring agent
• the particles of toner e.g., carbon black or similar pigment or coloring agent are repelled by the negative latent electrostatic image and deposited in the discharge areas, resulting in a reverse image from the original.
• an overall positive electrostatic charge is produced on a photoconductive surface, e.g., zinc oxide dispersed in a binder. This is followed by an imagewise discharge through light exposure so as to leave a positive charge in the unexposed areas. It is at this point that the liquid toner composition is applied.
• a photoconductive surface e.g., zinc oxide dispersed in a binder.
• the particles of the toner composition comprising the pigment or coloring agent are directed to the positively charged areas of the latent image.
• this results in the production of an identical reproduction of the original.
• the particles of toner e.g., carbon black or similar pigment or coloring agent, are repelled by the positive latent electrostatic image and deposited in the discharged areas, resulting in a reverse image from the original.
• a negatively charged liquid toner system which comprises an electrically insulating carrier liquid containing a pigment or coloring agent, a metallic soap, and a polymeric material.
• a further object ofthe present invention is to provide such a negatively charged liquid toner system comprising an electrically insulating carrier liquid, at pigment or a coloring agent, a metallic soap, and a polymeric material.
• a still further object of the present invention is to provide such a negatively charged liquid toner composition for use in electrostatic printing processes comprising an electrically insulating carrier liquid, a pigment, e.g., carbon black, a metallic soap, and a polymeric material said polymeric material comprising a copolymer of a vinyl ether and maleic anhydride.
• the liquid toner composition or system comprises as a base fluid any of the conventional electrically insulating carrier liquids generally employed in liquid developer and toner compositions.
• Such electrically insulating carrier liquids generally comprise solvent materials having the necessary dielectric constant, e.g. less than 3 and volume resistivity, e.g. in excess of 10 ohm centimeters so as to be acceptably employed in the electrostatic reproduction process.
• the electrically insulating carrier liquid of the liquid toner'system can comprise various solvents, e.g. cyclohexane, toluene, kerosene and mixtures thereof; various commercial petroleum and hydrocarbon solvents, e.g.
• Isopar G having a boiling range of from 3 l8-347F, a product of Humble Oil & Refining Co.; Cyclosol 43, having a boiling range of 334390F, or Shellosol 71, having a boiling range of 346-405F;both products of the Shell Chemical Co.; or Freons, a trade name for fluorocarbon compounds of E].
• duPont de Nemours & Co. such as Freon TF which has a boiling point of ll7.6F.
• the pigment or coloring agent employed in the negatively charged liquid electrostatic toner composition of the present invention can comprise any of those conventionally employed in electrostatic toners.
• the coloring agent or pigment can comprise carbon black and various forms thereof, e.g. channel black, furnace black, lamp black, and other black materials made by processes well known in the art, col ored pigments including the phosphotungstates and phosphomolybdate colors, alkali blue, and many azo pigments as well as nigrosine dyestuffs and triphenyl methane dyes.
• the pigment or coloring agent e.g. carbon black
• the pigment or coloring agent is suspended in the'carrier liquid containing the metallic soap and in the polymeric material which also acts as a dispersing agent because of the surface active characteristics thereof.
• the pigment comprises from about 0.01 to about 10 percent of the toner system or composition. Of course, slightly lesser or greater amounts can be employed when desired for particular purposes.
• the polymeric materials comprise copolymers of maleic anhydride and an alkyl vinyl ether and are represented by the following structural formula:
• R is an alkyl group of preferably 12 40 carbon atoms and n has a value of from about 1,000 to 25,000.
• the copolymers are produced by reacting maleic anhydride with a compound of the following formula:
• R is an alkyl of preferably 12 40 carbon atoms, so as to form the linear resinous copolymers of alkyl vinyl ether-maleic anhydride.
• the copolymers and their methods of preparation are disclosed in US. Pat. No. 2,047,398 (Reissue 23,514).
• copolymers posses anhydride groupings which are subject to entering into further chemical reaction, i.e. hydrolysis and/or esterification
• the nature of the medium to which these copolymers are added as well as the other additives present can give rise to polymeric derivatives of these copolymers e.g., copolymers of alkyl vinyl ether-maleic acid and partial amides and esters of poly(alkyl vinyl ether-maleic acid).
• Such derivatives are equivalent to copolymers of alkyl vinyl ether-maleic anhydride for the purpose of this invention.
• the polymer material is employed only in that amount necessary to provide a stable suspension or dispersion of the toner. Generally, such material is employed in the range of 0. 1-1 times the weight of the pig mentor coloring agent, and preferably within the range of 0.05 to 0.5 parts by weight of the pigment or coloring agent employed.
• the metallic soaps employed in the negatively charged liquid toner composition of the present invention can be such compounds as the metallic salts of fatty acids containing at least 6-7 carbon atoms and including naphthenic acid which is a cyclic aliphatic acid.
• the preferable soaps in the practice of this invention are the salts of naphthenic and octanoic acids including lead, copper, zinc, cobalt, silver, magnesium, manganese, iridium, cadmium, silver, aluminum, potassium, titanium, cerium, zirconium, ferric, sodium, lithium, calcium, and nickel naphthenates and octoates.
• octanoic acid and octoates as used in this description are meant to be broad enough to respectively cover the eight carbon Z-ethyl hexanoic acid and 2- ethyl hexanoates.
• Other metallic soaps such as the tallates, soyates, linoleates, resinates, palmitates, stearates annd oleates may also be used.
• the manner by which the liquid toner composition is produced is in no way critical, and accordingly, such composition can be prepared by conventional methods well known in the art, in this respect, it has been found that an ultrasonic dispersing unit, 3-roll mill, ball mill, colloid mills, high speed shear mixers, etc., are all applicable in the production of the dispersions employed in the liquid electrostatic toner system of the present invention.
• an ultrasonic dispersing unit 3-roll mill, ball mill, colloid mills, high speed shear mixers, etc.
• it is conventional to produce a concentrate of the toner and subsequently addd such concentrate to further insulating carrier liquid to provide the liquid ton-er composition employed in the electrostatic reproduction process.
• the toner composition was then employed in a conventional electrostatic copier to produce a reversed electrostatic reproduction when a negative charge is applied to the paper.
• the toner composition did not exhibit any tendency to settle out or to agglomerate.
• the print produced by the use of the toner composition of the present inventor was found to give a clear and sharp reproduction of the original having a reverse image, that is, the background areas of the reproduction were black whereas the printed material on the original was white. A copy having no background, good image fill. high black print density, and substantially no tendency to streak was obtained.
• Example III Example I is repeated except that 2.5 cc of the resulting toner concentrate was diluted to 0.5 liters with Freon TF.
• Freon TF duPont
• Freon TF is trichlorotrifluoroethane having a boiling point of ll7.6F, a dielectric constant of 2.41, and a specific resistivity of 2 X 10 ohm-cm.
• the toner composition was then employed in a moditied electrostatic copier characterized that the photoconductive zinc oxide binder layer was given an overall positive charge instead of an overall negative charge prior to imagewise exposure to produce an identical reproduction of the original. A copy having no background, good image fill, high black pring density, and substantially no tendency to streak was obtained.
• An electrostatic liquid toner comprising a. an electrically insulating carrier liquid comprising a hydrocarbon wherein said carrier liquid has a dielectric constant of less than 3 and a volume resistivity in excess of ohm centimeter; b. from about 0.01 to about, 10 percent ofa pigment; c. a metallic soap; and d. from 0.1 to 1 part by weight, per part by weight of said pigment, ofa copolymer of an alkyl vinyl ether and maleic anhydride wherein the alkyl group of said alkyl ether contains l2 to 40 carbon atoms.

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

Priority Applications (7)

Applications Claiming Priority (1)

Publications (1)

Family

ID=23169626

Family Applications (1)

Country Status (7)

Cited By (12)

Families Citing this family (4)

Citations (5)

• 1972
  • 1972-11-01 US US302885A patent/US3869397A/en not_active Expired - Lifetime
• 1973
  • 1973-10-05 AU AU61079/73A patent/AU6107973A/en not_active Expired
  • 1973-10-08 GB GB4681373A patent/GB1439626A/en not_active Expired
  • 1973-10-15 NL NL7314145.A patent/NL163334C/xx active
  • 1973-10-30 DE DE19732354259 patent/DE2354259A1/de active Pending
  • 1973-10-30 BE BE137230A patent/BE806713A/xx unknown
  • 1973-10-31 JP JP48122699A patent/JPS49110349A/ja active Pending

Patent Citations (5)

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