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
• • 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 use in the electrophotographic transfer process comprising a liquid carrier with an electric resistance of not less than 10 Q.cm and a dielectric constant not greater than 3, having dispersed therein a toner comprising particles of a colored substance coated with at least one resinous substance which will penetrate cloth or paper, together with fine particles being harder than the toner particles and having an average particle diameter of from 1 to 15 1,.
• the principal methods for developing electrostatic latent images formed on an electrophotographic copying material are the dry developing method employing a powdery toner and the wet developing method employing a liquid toner.
• the methods are also classified as direct and indirect, or transfer.
• direct process the final image is formed directly on the electrophotograhic material.
• transfer process the image is formed on the electrophotographic material and transferred to another support, such as plain paper.
• both dry and wet developing can be used in both the direct and the transfer methods.
• wet developing is that the edging effect which increases the resolving power of the finished product is minimized compared with the dry developing procedure.
• the major advantage of the transfer procedure is that the final product is on plain paper. Because of these advantages, it has long been a desideratum of the art to combine the transfer process with wet developing.
• the developer of this invention comprises a carrier liquid having an electrical resistance of at least l Q'cm and a dielectric constant up to 3, having dispersed therein a toner comprising particles of a colored substance coated with at least one resin which is capable of penetrating into paper or cloth together with fine particles being harder than the toner particles and having an average diameter of from 1 to l5;1.
• the average particle diameter of the fine particles is obtained by dispersing them in an appropriate liquid, placing a measured amount of the suspension on a thin glass plate, and forming a sandwich by placing another glass plate over the suspension.
• the thin layer of the suspension is photographed with a photomicroscope and the diameter of 200 to 1,000 particles within a visual field is measured.
• the average particle diameter represents the mode size, i.e., the particle diameter which has been detected most frequently.
• the colored particles employed in the preparation of the toners used in this invention include any of those pigments or dyes normally employed in the preparation of liquid developers.
• the particles are coated with a soft resin of the type normally employed in the preparation of printing inks.
• Such inks form images on paper because they readily penetrate the paper, thus forming an image which is strongly bonded thereto. The penetration also contributes to increasing the drying rates of the inks. Attempts to utilize these resins in previous methods of preparing toners for liquid development have not been successful.
• any of a wide variety of pigments or dyestuffs may be used as the colored materials for the toners of this invention.
• the following may be mentioned by way of example of typical materials presently commercially available: Carbon Black MITSUBISHI No. 44, Carbon Black MITSUBISHI No. (both of these are the manufacture of MITSUBISHI KASEI K.K.), Printex G, Special Black 15 (a manufacture of Deggusa Co.), Mogal A, Sutetex, Peerless 155 (all of these are the manufacture of Columbia Co.), Elftex 5 (a manufacture of Cabot Co.
• Acetylene Black (a manufacture of DENKI KAGAKU K.K.), Cyanine Black, Spirit Black (both of these are the manufacture of ORIENT KASEI K.K.), Aniline Black (a manufacture of I.O.l. Co., England), Brilliant Carmine 68 (a manufacture of SANYO SHIKISO K.K. Rhodamine B (a manufacture of TOYO INK K.K.
• Benzidine Yellow GNH (a manufacture of SANYO SHIKISO K.K., Ultra Rose E (a manufacture of TOYO INK K.K.), Cyanine SANYO SHIKISO K.K., Phthalocyanine Green E7G (a manufacture of DAINICHI SEIKA K.K.),Cyanine Blue LBG (a manufacture of SUMITOMO KAGAKU K.K.
• Benzidine Yellow GR (a manufacture of TOYO INK K.K.
• Oil Blue, Alkali Blue both of these are the manufacture of ORIENT KASEI K.K.), Ultra Blue B (a manufacture of TOYO INK K.K.), Spilon Yellow, Spilon Red (both of these are the manufacture of HODO- GAYA KAGAKU K.K.), Microlith Black C-T, Microlith Blue 4CT, Microlith Green CT, Microlith Yellow 2CT, Microlith Red R-T (all of these are the manufacture of CHIBA, Ltd.), Reflex Blue AG, etc.
• particles having a composition similar to these colored particles there are Graphofax Toner Powder No. 39-50, a dry toner (a manufacture of Hunt Co.), etc., and these are also applicable to the present invention. 1
• a variety of resinous substances may be purchased 0 prepared for use in the invention. They may be coated on the foregoing colored particles through kneading, for instance. They include, for example butyl rubbers such as ESSO Butyl 215 and E880 Butyl by ESSO Oil Co., isobutyl rubbers such as Vistanex LM and Vistanex MN by ESSO Oil Co., chlorinated isobutylene rubbers such as Butyl Rubber HT -l066, Butyl Rubber HT-l067 and Butyl Rubber HT-l068 by ESSO Oil Co., alkyd resins such as Beckozol I343, Beckozol J-l334, Beckozol J-534, Beckozol P-789, Beckorin P-75, Beckozol P-450, Beckozol J-6l l, Beckozol J-7l9 and Beckasite J-8l l by DAINIPPON INK K.K., isobutylene butylene copoly
• varnish, linseed oil, rosin, modified rosin, tung oil, soybean oil, fish oil, various waxes, various celluloses, asphalt, aliphatic amine resins, etc. may also be used.
• Typical examples of this type of resinous substances include KO-Blown Asphalt, TOKUKO-Blown Asphalt, S. P-Blown Asphalt (all of these are the manufacture of NIPPON SEKIYU K.K.), Varnish 30, Varnish 50, Alkyd-modified Varnish (all of these are the manufacture of DAINlPPON INK K.K.), Linseed Oil (a manufacture of WAKO JUNYAKU K.K.), etc.
• Mixtures of the above resins may be employed as well as mixtures of these highly penetrative resinous substances with other well known resins conventionally employed in wet developers for electrostatic photography, such as acrylic resins, styrene resins, polyester resins, etc., in the proportion of 0.5 4 parts by weight of the latter resin per 1 part by weight of the former resin.
• the quantity of penetrative resin coated on the particles of the colored substances is substantially the same as in conventional toners employed in the wetdeveloping method.
• the toners will include 1 30 parts by weight of resin to 1 part by weight of the particles of said colored substance.
• a resinous substance being capable of penetrating into a paper or a cloth refers to materials responding to the following test:
• a resinous substance is dissolved in a mixed solvent, the mixing ratio of toluene and petroleum aliphatic hydrocarbon being 1:1, to prepare a 40 wt.% resinous solution.
• a 0.5 mm thick metal plate having a hole mm in diameter is placed on an Indian paper and the hole is filled with the solution. Any excess resinous solution on the surface of the metal plate is removed with a spatula so that the quantity of filled resinous solution is just equal to the volume of the hole. The metal plate is removed gently so that the resinous solution alone remains on the paper. It is allowed to stand under atmospheric pressure at C. for 10 minutes and the diameter of a circle of the impregnated resinous solution is measured. If the circle is more than 20 mm in diameter, the resin is of sufficient permeability to be used in the invention. If it is less than 20 mm in diameter, the resin is not suitable for use in the invention.
• toners are suspended in the carrier liquid together with additional fine particles which are, generally speaking, harder than the toners so that they are not themselves crushed during transfer, and they help to prevent crushing of the toners.
• Typical examples of such toners include inorganic materials such as glass beads, zinc oxide, titanium dioxide, silica and the like. Many of the toner particles presently employed in the dry developing method can also be used as the fine particles of this invention.
• the weight ratio of toner to fine particles in the liquid developers of this invention is from 0. 1:1 to 1:1. Some variation from this range can be tolerated. It has been observed, however, that appreciably below this range there is not a satisfactory improvement in the formability of the image or its distinctness, while above the range there is an undesirable increase in the number of white spots in the body of the image.
• the average particle diameter of the fine particles is from 1 to 1511.. Only a relatively small amount of variation from this range can be tolerated. Below the range, there is a loss of image clarity; above it, there is an increase in the number of white spots.
• the toner particles suspended in the carrier liquid are adsorbed to the fine particlesv
• the fine particles therefore play, so to speak, the role of carriers for the toner particles. Therefore, unless the fine particles have a diameter as described above, they will not remain dispersed in the carrier liquid and a distinct image cannot be formed at the time of development or transfer.
• the ability to faithfully transfer the toner from the surface of the photoconductive layer of a copying material to the surface of a transfer material is enhanced by the ability of the fine particles to prevent crushing of the toner and its diffusion through capillaries of the paper fibers.
• the carrier liquid may be any of the conventional liquids utilized in ordinary liquid developers. They are generally characterized as petroleum aliphatic hydrocarbons with an electric resistance of at least 10 Qcm and a dielectric constant up to 3.
• commercial carriers which may be employed in the invention, there may be, for example: Shell S.B.P., Shellzol (all of these are the manufacture of Shell Oil Co.), lsopar E, lsopar G, lsopar H, lsopar K, lsopar L ⁇ lsopar M, Naphtha No. l, Naphtha No. 2, Naphtha No. 3, Naphtha No. 5, Naphtha No.
• Butyl rubber 20 g 50% toluene solution of styrene butadiene copolymer (molar ratio 30 z lsopar G mixture of the above composition was subjected to 24" hours kneading for dispersion in a ball-mill, whereby a concentrated toner containing a highly penetrative resin was prepared. Subsequently, by dispersing 25 g of this concentrated toner and 15 g of zinc oxide (having average particle diameter of 1.];1.) in 500 ml of lsopar G, a liquid developer having a satisfactory transferability for use in wet-type electrostatic photography was prepared.
• An electrostatic latent image was formed on a selemium photoconductive plate through electrification and exposure by the known method, and was then developed with the foregoing liquid developer. Next, by superposing an ordinary paper on the image formed by developing as above, the image was transferred to the paper. The transferred image was distinct and not blurred.
• EXAMPLE 2 In the same way as in Example 1 except for replacing the fine particles of zinc oxide with titanium oxide having the same particle diameter as the zinc oxide, a liquid developer for use in wet-type electrostatic'photography was prepared.
• EXAMPLE 3 In the same way as in Example 1 except for replacing the fine particles of zinc oxide with silica (having average particle diameter of 2p), a liquid developer for use in wet-type electrostatic photography was prepared.
• EXAMPLE 4 Ultra Blue B g Special Black 50 g lsoprene 30 g 50% toluene solution of methyl methacrylate styrene copolymer (molar ratio 50 50) 60 g A mixture having the above composition was subjected to 24 hours kneading for dispersion in a ballmill, whereby a concentrated toner containing a highly penetrative resin was prepared. Subsequently, by dispersing 25 g of this concentrated toner and 0.8 g of glass beads (having average particle diameter of 5p.) in 50 ml of Isopar H, a liquid developer having a satisfactory transferability for use in wet-type electrostatic photography was prepared.
• Example 2 An electrostatic latent image formed in the same way as in Example 1 was developed with the foregoing liquid developer, and this image was transferred to an ordinary paper superposed thereon. As a result, substantially all of the toner on the photoconductive plate was transferred to the paper, and the transferred image was distinct.
• Example 5 When development and transfer were performed in the same way as in Example 1 utilizing this liquid developer, the transferred image on an ordinary paper was as good as that in Example 5, and the toner transferability was also satisfactory.
• Control Developer Test Procedure A selenium photoconductive plate was first charged with electricity by corona discharge. Then, upon superposing thereon a chart for measuring resolving power with one to several tens of lines drawn within fixed lengths, it was exposed and then developed with control developer-A. Subsequently, an ordinary paper was superposed on the image-carrying surface and was thereafter stripped off, to transfer the image from the selenium photoconductive plate to the paper. Then, the resolving power in lines per mm was determined.
• a liquid developer for use in electrophotographic transfer process which comprises: a carrier liquid having an electric resistance of at least lO fl'cm and a dielectric constant up to 3; a toner dispersed in said carrier liquid, said toner comprising particles of a colored substance and at least one resinous substance coated on the surface of said particles, said resinous substance the fine particles selected from the group consisting of glass beads, zinc oxide, titanium oxide and silica.
• a liquid developer according to claim 1, wherein the ratio of resinous substance to particles of colored substance is from I 30 parts by weight of the former to 1 part by weight of the latter.

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

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Cited By (14)

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Citations (4)

• 1972
  • 1972-07-27 JP JP47074604A patent/JPS4934328A/ja active Pending
• 1973
  • 1973-07-27 US US383259A patent/US3915874A/en not_active Expired - Lifetime

Patent Citations (4)

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