Abstract: An electrophotographic device performing reversal development to develop the portion with lower absolute value of potential in an electrophotographic process having steps of primary charging, imagewise exposure, developing and cleaning, and having a photosensitive member of the lamination type which uses a layer coated with an organic pigment dispersed in a solvent or in a solvent and a polymer binder, as the charge generation layer, wherein the potential of the photosensitive member and process conditions are under constant conditions, said constant conditions being within the range as defined by the following formula of Vd, t and V.sub.H, when the surface potential of the photosensitive member immediately after charged with a primary charger is defined as Vd (V), the time from primary charging to toner development as t (sec) and further the surface potential of the photosensitive member at which the toner developing density becomes the half value of the saturated density as V.sub.H (V):.vertline.V.sub.H .

Abstract: An imaging system in which an imaging member comprising a substrate and an electrically insulating softenable layer on the substrate, the softenable layer comprising migration marking material located at least at or near the surface of the softenable layer spaced from the substrate, and a charge transport material in the softenable layer is imaged by eletrostatically charging the member, exposing the member to activating radiation in an imagewise pattern, decreasing the resistance to migration of marking material in the softenable layer sufficiently to allow the migration marking material struck by said activating radiation to retain a slight net charge which allows only slight agglomeration, slight coalescence, slight migration in depth of marking material towards said substrate or combination thereof in image configuration during a further decreasing of the resistance to migration towards the substrate in image configuration, and further decreasing the resistance to migration of marking material in the soft

Abstract: A particulate material suited for serving as carrier particles for finely-divided toner particles in magnetic brush toner-carrier development of electrostatic charge patterns, said carrier particles comprising finely divided magnetite powder dispersed in a resin binder, characterized in that said magnetite powder is a mixture of magnetites wherein one type (A) of the magnetite has an oil absorption number in the range of 10 to 20 g/100 g pigment and another type (B) of the magnetite has an oil absorption number in the range of 20 to 40 g/100 g pigment. The binder contains hydrophilic functional groups and has an acid number in the range of 5 to 50 KOH/g.

Abstract: A single component pressure fixable toner composition comprised of resin particles selected from the group consisting of ethylene/propylene copolymers, ethylene-co-vinyl acetate polymers, polyamides, and mixtures thereof, magnetite, and a release fluid therein, which toner contains conductive particles on the surface thereof, and wherein the magnetite is present in an amount of from about 50 to about 80 percent by weight, and the toner has a resistivity of about 10.sup.4 to about 10.sup.7 ohm-cm.

Abstract: A cold pressure fixing toner composition comprised of a core containing a polymer component and magnetic pigment particles, and wherein the core is encapsulated within a shell comrised of the interfacial polycondensation reaction of a first polyisocyanate component and a second amine component, which toner includes thereon an electroconductive material obtained from a water based dispersion of said material in a polymeric binder, said first polyisocyanate component being selected from the group consisting of PAPI 27, PAPI 135, PAPI 94, PAPI 901, Isonate 143L, Isonate 181, Isonate 125M, Isonate 191, and Isonate 240; and said second amine component selected from the group consisting of ethylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, p-phenylenediamine, m-phenylenediamine, 2-hydroxy trimethylenediamine, diethylenetriamine, triethylenetetraamine, tetraethylenepentaamine, 1,8-diaminooctane, xylylene diamine, bis(hexamethylene)triamine, tris(2-aminoethyl)amine, 4,4'-methylene bi

Abstract: Disclosed is a method of making particulates. A solution is formed of a solvent. a first polymer having an intrinsic viscosity of at least 0.5, and a second polymer having an intrinsic viscosity of less than 0.5. The solution is atomized with a gas to form droplets of the solution suspended in the gas. The evaporation of the solvent leaves the particles suspended in the gas and the particles are collected to form the toner. Also disclosed is toner made by this method, and a method of making an electrographic printing plate by developing an electrostatic image with the toner, transferring the developed image to a substrate, and fixing the transferred image on the substrate. Also disclosed is an electrographic printing plate made according to that method.

Abstract: A charge director composition dispersed in at least one solvent comprising:A. a salt mixture comprised of 1-10 parts by weight each of:(i) a chromium salt of a C.sub.14-18 alkyl salicylic acid;(ii) a calcium didecyl sulfosuccinate; and(iii) a salt of the didecyl ester of sulfosuccinate acid and at least 50% of the basic nitrogen radicals of a copolymer of lauryl methacrylate, stearyl methacrylate and 2-methyl-5-vinyl pyridine, said copolymer having a vinyl pyridine content of 20-30% by weight and an average molecular weight of 15,000-250,000; andB. a salt-free copolymer of (i) laurylmethacrylate and (ii) a monomer selected from 2- or 4-vinylpyridine, styrene and N,N-dimethylaminoethylmethacrylate and mixtures thereof, said copolymer having a molecular weight from about 15,000 to about 100,000, and the weight ratio of monomers B(i) to B(ii) is from about 4:1 to about 50:1; and wherein the weight ratio of B:A is from 10:3 to about 40:3.

Abstract: An electrostatic method is disclosed for providing multicolor imaging from a single toner bath. The toner bath is a blend of individual toners, each of which contains a color precursor different from the others.

Abstract: The present invention relates binder type carriers, the surface of which is firmly adhered with charge controlling agents, by which the elastic charge of the carriers can be controlled to a desirable polarity and a level without the influence of the chargeability inherent to the magnetic powders themselves.

Abstract: A developer for developing electrostatic latent images comprises negatively chargeable toner particles and hydrophobic, negatively chargeable silica fine power,said silica fine powder being obtained by treating silica fine powder with a silane coupling agent represented by the following formula:RmSiYn or Y.sub.3 --Si--NH--Si--Y.sub.3and treating further said treated silica fine powder with a silicone oil having the structure: ##STR1## An image forming method comprises forming an electrostatic latent image on a photosensitive drum; developing said latent image with a developer to form toner images, said developer comprising negatively chargeable toner particles and, hydrophobic, negatively chargeable silica fine powder,said silica fine powder being obtained by treating silica fine powder with a silane coupling agent represented by the following formula:RmSiYn or Y.sub.3 --Si--NH--Si--Y.sub.

Abstract: A toner for developing electrostatic latent images which comprises a colorant and two kinds of polyester is disclosed.The fFirst polyester is a nonlinear polyester that is composed of monomers including monomers of trivalence or higher valency and which satisfies the following conditions A1 and A2, the second polyester is a nonlinear polyester that is composed of monomers including monomers of trivalence or higher valency and which satisfies the following conditions B1 and B2, and the difference between the softening points of said first and second polyesters is at least 10.degree. C.condition A1: the monomers of trivalence or higher valency represent from 0.05 mol % to less than 15 mol % of all the monomers present;condition A2: the softening point is in the range of from 120.degree. C. to 160.degree. C.;condition B1: the monomers of trivalence or higher valency represent from 0.05 mol % to less than 15 mol % of all the monomers represent;condition B2: the softening point is in the range of from 80.degree.

Abstract: An electrophotographic photosensitive member has a photosensitive layer on an electroconductive support, characterized in that the surface layer contains a fluorine type resin powder and a fluorine type block copolymer.

Abstract: This invention relates to carriers for electrophotography comprising a binder component including a binder resin, a polymeric-magnetic coordination complex, and an inorganic magnetic material dispersed in the binder component at the ratio of 100-900 parts by weight to 100 parts by weight of the binder component, which effect the electrical resistance as well as magnetic properties. Carriers of the invention are suitable, in particular, for a copier furnished with a high rotation developing sleeve.

Abstract: A toner composition for a two-component type developer capable of developing electrostatically charged images formed on a photoreceptor having a surface layer comprising organic substances, wherein the toner composition contains a fatty acid bisamide compound as an external additive.

Abstract: A method of producing toner particles for use in electrophotography where the particles have a colored resin core particle containing a resin and a colorant and charge controlling layer on the particle's outer surface. The charge controlling layer contains a charge controlling agent but not any colorant. The method comprises the steps of:(1) preparting toner core particles by mixing, kneading, crushing and sorting a first material including a resin material and a colorant,(2) preparing charge controlling particles with smaller diameters than the toner core particles by mixing, kneading, crushing and sorting a second material including a charge controlling agent, and(3) thereafter mixing the toner core particles the said charge controlling particles and causing a charge controlling layers to be formed around the toner core particles by applying a pressure to the mixed particles.

Abstract: A photoconductive composition is disclosed, comprising at least an inorganic photoconductive material, a sensitizing dye and a resin binder wherein the sensitizing dye is a compound containing at least one acidic group in the molecule thereof as represented by the formula (I): ##STR1## wherein all the symbols are as defined in the appended claims.

Abstract: A toner for developing electrostatic latent images, comprises:100 parts by weight of a binder resin;20 to 200 parts by weight of magnetic powder; and0.

Abstract: A negatively charged photoconductive imaging member comprised of a supporting substrate; an electron polysilylene transporting layer; a metal oxide layer; and thereover a photogenerating layer comprised of hydrogenated amorphous silicon.

Abstract: A white toner comprising a fixing resin and dispersed therein, a titanium dioxide pigment of high purity containing at least 99% by weight of TiO.sub.2, not more than 0.1% by weight of Al.sub.2 O.sub.3 and not more than 0.05% by weight of SiO.sub.2 as a white pigment. The white toner has markedly improved hygroscopicity as a result of using the white pigment in which the contents of metal oxides such as Al.sub.2 O.sub.3 and SiO.sub.2 are reduced to very small amounts. The toner can thus retain the stable and uniform amount of triboelectric charge, and permits effective circumvention of troubles such as the reduction of image density, background fog and image blurring.

Abstract: A developer for electrophotography is disclosed, which comprises toner particles containing therein at least an olefin resin having a melt index of 25.about.700 g/10 min, which toner particles may comprise a colorant which is prepared by a flushing method by using a pigment component and an olefin resin having a melt index of 25.about.700 g/10 min, when necessary, with addition thereto a humic acid component selected from the group consisting of humic acid, a salt of humic acid, and a humic acid derivative.