Abstract: A toner composition having particles substantially in the spherical form and comprises a binder resin and carbon black having a number-average particle size of 20 to 500 millimicrons and a standard deviation of particle size distribution of 70 millimicrons or smaller.

Abstract: A photoconductor for electrophotography comprises an electrically conductive substrate and a laminate formed on the substrate. The laminate includes a charge generating layer including a specific squarylium compound as a charge generating substance and a charge transporting layer including a hydrazone compound. One type of the specific squarylium compound is represented by the following general formula. ##STR1## Wherein, each of R1, R2, R5 and R6 stands for one of an alkyl group, an aralkyl group and alkenyl group, each of which groups may be or not may be substituted, or R1, forms a ring together with R2, R5 forms a ring together with R6, each of R3 and R4 stands for one of hydrogen atom, a halogen atom, a hydroxy group, an alkyl group and an alkoxy group.

Abstract: An electrophotographic photoreceptor comprising a support having thereon at least one photoconductive layer containing at least inorganic photoconductive particles and a binder resin, wherein said binder resin has a weight average molecular weight of from 1.times.10.sup.3 to 5.times.10.sup.4 and comprises (A) at least one resin comprising, as a polymerization component, (a-i) not less than 30% by weight of at least one repeating unit represented by formula (I) or (II): ##STR1## wherein X.sub.1 and X.sub.2, which may be the same or different, each represents a hydrogen atom, a hydrocarbon group having from 1 to 10 carbon atoms, a chlorine atom, a bromine atom, --COY.sub.1 or --COOY.sub.2, wherein Y.sub.1 and Y.sub.2 each represents a hydrocarbon group having from 1 to 10 carbon atoms, provided that both X.sub.1 and X.sub.2 do not simultaneously represent a hydrogen atom; and W.sub.1 and W.sub.

Abstract: An electrophotographic photoreceptor comprising a support having provided thereon at least one photoconductive layer containing at least inorganic photoconductive particles and a binder resin, is disclosed wherein said binder resin comprises (1) at least one resin (A) containing at least one acidic group selected from --PO.sub.3 H.sub.2, --SO.sub.3 H, --COOH, and ##STR1## wherein R represents a hydrocarbon group, at the terminal of the polymer main chain thereof, and (2) at least one of a thermosetting resin (B) containing a crosslinking functional group and a crosslinking agent. The photoreceptor exhibits improved electrostatic characteristics. The photoreceptor provides an electrophotographic lithographic printing plate precursor which exhibits excellent image reproducibility irrespective of a variation of environmental condition at the time of electrophotographic processing and produces a printing plate having improved printing durability and causing no background stains.

Abstract: A magnetic toner comprising a binder resin, magnetic powder and 0.1-10 wt. % (based on resin component) of a low-molecular weight polyalkylene, the binder resin comprising a vinyl-type polymer having 5 to 80 wt. % of a tetrahydrofuran (THF)-insoluble; the magnetic toner having a melt index of 0.2 to 12 g/10 min. (125.degree. C., 10 kg load); the residual magnetization .sigma..sub.r and the volume-average particle size d of the magnetic toner satisfying the following formula:3.7-0.11d.ltoreq..sigma..sub.r .ltoreq.6.5-0.23d,wherein .sigma..sub.r represents a residual magnetization (emu/g) under an external magnetic field of 1 KOe and d represents a volume-average particle size of 3 to 16 microns.

Abstract: The photoconductive layer of an electrophotographic plate, such as used to record radiographic patterns, is overcoated with a thin dielectric layer having luminescing (e.g., fluorescing or phosphorescing) properties. Upon being uniformly charged and imagewise exposed to actinic radiation (i.e. radiation to which the photoconductive layer responds), the resulting charge pattern is developed with toner. The toner-bearing surface of the electrophotographic plate is irradiated with radiation adapted to excite the luminescent overcoat. The toner image serves, in effect, to mask any luminescence by the underlying overcoat, thereby giving rise to a luminescent contrast image which may be recovered by laser scanning or CCD techniques, or photographed directly.

Abstract: Disclosed is a toner for developing statically charged images, which has a substantially spherical shape and comprises a copolymer comprising, as a constituent, a water-soluble monomer having a group--SO.sub.3 X in which X stands for hydrogen, sodium, potassium or calcium.This toner has a good charge characteristics, an excellent flowability and a uniform particle size. If this toner is used, fogging is not caused in a copied image, and the obtained image is sharp and has an excellent resolving power.This toner is prepared by a process for the preparation of a toner for developing statically charged images, which comprises incorporating a copolymer comprising a water-soluble monomer having a group--SO.sub.3 X in which X stands for hydrogen, sodium, potassium or calcium and an oil-soluble monomer into a polymerizable composition comprising a polymerizable monomer, an initiator and a colorant, and suspension-polymerizing the composition.

Abstract: A toner comprising a vinyl polymer having a hydroxyl number of 50 to 350 and a glass transition point of 35.degree. to 100.degree. C., obtained from one or more monomers having a secondary hydroxyl group and, if necessary, one or more vinyl monomers copolymerizable with the vinyl monomer having a secondary hydroxyl group, is excellent in resistance to adhesion to non-rigid polyvinyl chloride and resistance to blocking under high humidity.

Abstract: An electrophotographic photoreceptor comprising: (1) an electrophotographic photosensitive layer which comprises a charge carrier transporting compound and a charge carrier generating compound, or (2) an electrophotographic photosensitive layer which comprises a charge carrier transporting compound layer and a charge carrier generating compound layer, on an electrically conductive support, wherein said charge carrier generating compound is a bis-azo compound represented by formula (I): ##STR1## wherein, Ar.sup.1, Ar.sup.2, Ar.sup.5 and Ar.sup.6 represent aryl groups, Ar.sup.3 and Ar.sup.4 represent arylene groups, and R.sup.1 represents a hydrogen atom or an SO.sub.3 Na group.

Abstract: An image fixing method for use in a wet-type electrophotographic copying machine is disclosed, which comprises the steps of: (1) developing a latent electrostatic image formed on an electrophotographic photoconductor element to a visible toner image by use of a developer comprising a thermal cross-linking toner and a carrier liquid, (2) transferring the visible toner image to a transfer sheet having an oil absorption coefficient .alpha. of 1.0.times.10.sup.-2 cm/sec or more, which is assessed by dividing the thickness of the transfer sheet by the time required for a drop of the carrier liquid placed on the front side of the transfer sheet to spread to a diameter of 1 cm on the back side of the transfer sheet, to form a transferred image on the transfer sheet, and (3) fixing the transferred image to the transfer sheet by bringing a heat application means into direct contact with the transferred image.

Abstract: Disclosed is an electrophotographic magnetic toner comprising 40-80% binder resin, a waxy material such as a low molecular weight polypropylene or polyethylene, a charge control agent and 20-60% iron oxide having a number average particle size of 0.2-0.7 microns and wherein trivalent Fe is present in excess and wherein the iron oxide contains 16-25% FeO and about 75-84% Fe.sub.2 O.sub.3.

Abstract: An electrophotographic photoconductor which comprises an electroconductive support; an undercoat layer formed thereon comprising (i) a reaction product between an active-hydrogen-containing compound having a plurality of active hydrogens and an isocyanate-group-containing compound, which reaction product serves as a binder resin, and (ii) finely-divided particles of indium oxide dispersed in the reaction product; and a photo-sensitive layer formed on the undercoat layer. The indium oxide may be partly replaced by metal oxide, metal fluoride, metal nitride, metal carbide or metal boride in an amount of not more than 50 wt. %.

Abstract: High resolution, photosensitive electrostatic master which is positive-working with a single imagewise exposure comprising a conductive support bearing a layer of a photosensitive composition consisting essentially of (A) at least one polymeric binder, (B) a hexaarylbiimidazole photooxidant, (C) leuco dye, preferably stabilized, oxidized by (B), (D) a nonionic halogenated compound, preferably a hydrocarbon, and (E) compatible plasticizer. A process of making positive images by a single imagewise exposure is described. The master is useful in making proofs that duplicate the image achieved by printing, etc.

Abstract: Disclosed is an electrostatic recording medium comprising an electroconductive support and as formed thereon a dielectric layer containing an insulating resin and a pigment, said dielectric layer carrying a surface static charge of a polarity opposite to that of a charge to be applied for image formation.

Abstract: A process for fabricating an electrophotographic imaging member is disclosed which involves providing an electrically conductive layer, forming an aminosilane reaction product charge blocking layer on the electrically conductive layer, extruding a ribbon of a solution comprising an adhesive polymer dissolved in at least a first solvent on the electrically conductive layer to form a wet adhesive layer, drying the adhesive layer to form a dry continuous coating having a thickness between about 0.08 micrometer (800 angstroms) and about 0.

Abstract: An electrophotographic recording material which comprises an electrically conductive support having thereon a double layer of a charge generating layer in contiguous relationship with a charge transporting layer comprising a positive charge transporting compound corresponding to the following general formula (I): ##STR1## wherein: R represents hydrogen or an aliphatic or cycloaliphatic group including these groups substituted by non-ionic substituents,each of R.sup.1 and R.sup.2 (same or different) represents a C.sub.1 -C.sub.6 alkyl group or an aryl group, andZ represents the atoms necessary to close an adjacent aromatic nucleus or aromatic ring system including such nucleus or ring system substituted with one or more substituents of non-ionic character.

Abstract: A developer for an electrostatic latent image is described, which comprises a toner powder and a fine powder having a particle size smaller than that of the toner powder, said fine powder being made of a polymer obtained by soap-free emulsion polymerization.

Abstract: An electrophotographic photosensitive member has a photosensitive layer on an electroconductive support, characterized in that said photosensitive layer contains a disazo pigment of the formula (1), wherein A.sub.1 and A.sub.2, which may be either the same or different, each represent a coupler residue having a phenolic hydroxyl group.

Abstract: This invention relates to a toner for development of electrostatic images to be used for development of electrostatic images formed in electrophotography, electrostatic printing, electrostatic recording, etc., and an image forming method by use thereof.

Abstract: An electrophotographic developer composition comprises a binder resin, which comprises a polyester as the major component, said polyester obtained by co-condensation polymerization of(i) a diol component represented by the general formula: ##STR1## wherein R is an ethylene or propylene group and x and y are each an integer of 1 or more, with the proviso that the average sum total of x and y is 2 to 7, with(ii) a dicarboxylic acid, an anhydride or a lower alkyl ester thereof and(iii) a polycarboxylic acid having at least three carboxyl groups or an anhydride or a lower alkyl ester thereof or a polyhydric alcohol having at least three hydroxyl groups and having an OHV/AV value of at least 1.2 wherein AV is an acid value of the polyester and OHV is a hydroxyl value thereof, and at least two charge controllers.