Abstract: A cleaning method is provided for electrostatic copying apparatus of the transfer type in which a polarizable magnetic toner is used as a developer to remove residual toner from the surface of a photoconductive member after the transfer of toner images. The method comprises the steps of charging the toner remaining on the surface of the photoconductive member to the same polarity as the charge for sensitizing the surface of the photoconductive member after the transfer of a toner image, uniformly exposing the photoconductive surface simultaneously with or after the charging step, and thereafter removing the residual toner from the photoconductive surface by magnetic attraction.

Abstract: A photosensitive paper for electrophotography comprising a paper substrate, an electrophotographic photosensitive layer formed on one surface of the substrate and an electrically conductive coating layer formed on the other surface of the substrate, which electrically conductive coating layer comprises an electrically conductive binder medium and a fine powder of a fluorine resin distributed predominantly in the surface portion of the electrically conductive coating layer, is disclosed.This photosensitive paper is satisfactory in all of the following properties; adaptability to the paper feeding operation, the scratch resistance of the photosensitive layer, the blocking resistance and electric characteristics irrespective of the humidity conditions in the operation atmosphere.

Abstract: In a laminated photosensitive material for electrophotography, an intermediate layer comprising, incorporated in a binder, phthalocyanine or a phthalocyanine derivative and a polycyclic aromatic nitro compound at a specific ratio is formed on an electrically conductive substrate, and a top layer comprising an organic polymeric photoconductor and the above polycyclic aromatic nitro compound at a specific ratio is laminated on the intermediate layer. In this photosensitive material, the dark decay speed is controlled in a range suitable for application to the repeated copying operation and the residual potential left on the exposure area can be reduced to a negligible level. Accordingly, occurrence of fogging is prevented and the toner transfer efficiency is improved. Further, this photosensitive material has improved mechanical, chemical and electric durabilities, and therefore, the life of the photosensitive material is remarkably prolonged.

Abstract: In a photosensitive material for electrophotography, an intermediate layer comprising an organic polymeric photoconductor and a polycyclic aromatic nitro compound at a specific ratio is formed on an electrically conductive substrate, and a top layer comprising, incorporated in a binder, phthalocyanine or phthalocyanine derivative and the above polycyclic aromatic nitro compound at a specific ratio is laminated on the intermediate layer. In this photosensitive material, the dark decay speed is controlled in a range suitable for application to the repeated copying operation and the residual potential left on the exposure area can be reduced to a negligible level. Accordingly, occurrence of fogging is prevented and the toner transfer efficiency is improved. Further, this photosensitive material has improved mechanical, chemical and electric durabilities, and therefore, the life of the photosensitive material is remarkably prolonged.

Abstract: A transfer sheet on which toner images free of broadening of edge portions and having sharp contours can be transferred even in the electrophotography or electrostatic printing of the transfer type using conductive or semiconductive toners, i.e., magnetic toners, is disclosed. This transfer sheet is characterized in that a conductive or semiconductive toner-receiving face having a volume specific resistance of at least 3.times.10.sup.13 .OMEGA.-cm is formed on at least one surface of a substrate of the transfer sheet.

Abstract: A switch device for an electrostatic photographic copying machine having a reciprocally movable member reciprocating from a rest position and returning thereto during each copying operation of the copying machine, and a drive driving the movable member. The switch device has an actuating member movable relative to the copying machine body and is toward a non-operating position. An operating member engages with the actuating member for moving it to an operating position. A retaining device engages the actuating member for holding the actuating member in the operating position after it has been moved to the operating position. A switch actuating the drive for the movable member is engageable by the actuating member for actuating the drive means when the movable member is in the operating position and actuating the switch for deactuating the drive when the movable member is in the non-operating position.

Abstract: A method of and apparatus for synchronously transferring an original and a sheet of copying paper for electrostatic photoduplication. A paper feeding device feeds the sheets of copying paper one at a time until the front edge reaches a predetermined position at a front edge stop. The sheet of copying paper is held at the predetermined position on standby for a period of time, and then a paper transfer device transfers it to move the front edge to an exposure point. At the same time an original placed on a mount is moved from a stopping point in the cycle of movement of the mount to a position in which the leading edge of the original is at an irradiation point optically aligned with the exposure point. The period of time during which the copying paper is fed from the supply, held in the predetermined position, and then moved to the exposure position is equal to the time for moving the mount for the original from a predetermined point along the path of movement of the mount to the irradiation point.

Abstract: An electrostatic photographic copying machine includes a device for automatically exchanging used master paper with fresh master paper on a master holding body, and for indicating when such an exchange should be initiated. The machine includes an apparatus for cleaning the fixing roller, an apparatus for adjusting the amount of toner supplied to the developer, a transfer device whereby improper discharge is prevented, a transfer paper jam detector, and a device for improved mixing of developer.

Abstract: A transfer sheet for electrostatically transferring thereon an electrically conductive or electrically semi-conductive toner in electrostatic photography or electrostatic printing, which comprises a substrate and a toner-receiving layer formed on at least one surface of the substrate, which toner-receiving layer contains a composition comprising (A) a thermoplastic acrylic polymer having a carboxyl group content of 2 to 30% by weight and (B) a thermosetting resin reactive with the acrylic polymer (A), and a process for preparing this transfer sheet by using an aqueous coating composition are disclosed. In this transfer sheet, the electric resistance can be maintained at a high level even under high humidity conditions, and a toner image can be transferred on this transfer sheet at a high transfer efficiency.

Abstract: An electrophotographic photosensitive material suitable for offset printing and lithography comprising a flexible substrate, an electroconductive back coat layer formed on one surface of the substrate, an electroconductive intermediate layer formed on the other surface of the substrate and a photoconductive layer formed on the intermediate layer, said photoconductive layer being composed of a fine powder of a photoconductor dispersed in an electrically insulating resin, wherein said intermediate layer is composed of a composition comprising (A) an acrylic resin, (B) a vinyl acetate polymer having a degree of polymerization of 100 to 1700 and (C) a resinous conducting agent, in said composition the weight ratio of acrylic resin (A)/vinyl acetate polymer (B) is in the range of 4/1 to 10/1 and the amount of the conducting agent (C) is 20 to 100 parts by weight per 100 parts by weight per 100 parts by weight of the sum of the components (A) and (B), said intermediate layer has such a multi-layer distribution stru

Abstract: An electrostatic photographic copying machine includes a photosensitive body having a photosensitive layer on its surface, a charging apparatus, a developing device and a transfer device arranged along a moving passage of the photosensitive body. An optical system projects an image of an original onto the surface of the charged photosensitive body, and a fixation apparatus fixes a transferred image onto copying paper.

Abstract: An apparatus for developing an electrostatic latent image formed on the surface of an electrostatic latent image-bearing material by applying a powdery developer, wherein means are provided for bringing the surface of a developer-retaining member retaining a layer of the powdery developer thereon into rolling contact with the surface of the image-bearing material in such a relation that a reservoir zone of the developer is formed at least upstream of the zone of rolling contact between the two surfaces, and means are provided for physically disturbing the developer in the reservoir zone to cause the developer to make an irregular motion.

Abstract: A process for preparing a photosensitive material for electrostatic photography having an improved memory resistance, which comprises a photoconductive layer on an electrically conductive substrate, the photoconductive layer comprising (1) a finely divided inorganic photoconductor, (2) 5 to 50 parts by weight, per 100 parts by weight of the photoconductor of an electrically insulating organic synthetic resin binder having a specific resistance of at least 10.sup.14 ohm-cm, and (3) 0.001 to 1 % by weight, based on the photoconductor, of at least one photo-memory erasing compound selected from alkali metal dichromates, which process comprises forming the photoconductive layer by applying a coating composition to the electrically conductive substrate at a coating weight of 5 to 50 g/m.sup.

Abstract: A magnetic toner for electrostatic photography consisting essentially of spherical particles of a composition comprising a fine powder of a magnetic material having an average particle size not exceeding 1000 m.mu. and being dispersed in a binder resin, said powdery magnetic material being present in an amount of 25 to 75% by weight based on the composition, spherical particles of said composition having such a particle size distribution that particles having a particle size larger than 44 .mu. occupy up to 10% of the total particles and particles having a particle size smaller than 2 .mu. occupy up to 10% of the total particles, wherein said fine powder of the magnetic material is distributed predominantly in the surface layer portion of each spherical particle and said spherical particles have a volume resistivity not higher than 1 .times. 10.sup.11 .OMEGA.-cm as measured in a magnetic field of about 680 gauss under a voltage of 1000 V.

Abstract: A pressure fixing developer for electrostatic photography comprising a finely divided magnetic material and a binder as effective components and consisting essentially of substantially spherical particles of said finely divided magnetic material dispersed in a solid medium of said binder, said binder medium being composed of a resin composition comprising (a) 25 to 65% by weight based on the total binder of a hydrogenated styrene resin, (b) 5 to 45% by weight based on the total binder of a wax having a melting point of at least 60.degree. C. and (c) 10 to 30% by weight based on the total binder of a copolymer of anlefin with a carbonyl group-containing, ethylenically unsaturated monomer.

Abstract: A corona discharge device including a corona discharge electrode, an opposing electrode disposed opposite to the corona discharge electrode, a high voltage alternate current source electrically connected between the two electrodes, and a grid provided in a corona discharge current flow path between the two electrodes. The grid is grounded through a nonlinear bias element.

Abstract: A developer for electrostatic photography comprising as indispensable components a fine powder of a magnetic material and a binder resin, said developer consisting essentially of a dry blend of (A) substantially spherical particles of a composition comprising a medium of said binder resin and said fine powder dispersed in the binder resin medium and (B) a finely divided solid conducting agent having a particle size smaller than 1/10 of the size of the spherical particles (A), said spherical particles (A) having a crater-like rough surface, said finely divided solid conducting agent (B) being stuck to said spherical particles (A) through said crater-like rough surfaces thereof, and the volume resistivity of said dry blend being not higher than 1 .times. 10.sup.11 .OMEGA.-cm.

Abstract: Method and apparatus for developing an electrostatic latent image formed on the surface of an electrostatic latent image-bearing material by applying a powdery developer, wherein the surface of a developer-retaining member retaining a layer of the powdery developer thereon is brought into rolling contact with the surface of the image-bearing material in such a relation that a reservoir zone of the developer is formed at least upstream of the zone of rolling contact between the two surfaces, and the developer in the reservoir zone is physically disturbed.

Abstract: A liquid developer comprising a dispersion of a dye or pigment having a long chain alkyl group in their molecular structure in a liquid hydrocarbon. The liquid developer for electrophotography is excellent in dispersibility of the image-forming dye or pigment particles, uniformity in charge polarity, storage stability, distinct-image forming ability and image-fixing property, and such liquid developer can be prepared without aid of conventional modifiers such as control agents dispersing agents, and fixing agents.

Abstract: A contact heat fixing device which comprises a driving heated roller having a heating mechanism disposed in the interior thereof and a surface coated with an offset preventing material, a press roller which is rotated in intimate contact under pressure with said heat roller, a vessel for containing therein an offset preventing liquid and a feed mechanism for supplying the offset preventing liquid to the heated roller from the vessel, fixation of a toner image being accomplished by the passage of a support having the toner image thereon through the nip position of the heated roller and the press roller, wherein said feed mechanism includes an applicator for applying the offset preventing liquid to the surface of the heated roller and supply means for supplying the offset preventing liquid from the vessel to the applicator, said applicator being arranged so that it can shift between a position (PI) where it has a pressing contact with said supply means and a position (P2) where it has a pressing contact with sa