Abstract: A toner for developing an electrostatic image has colored resin particles-(A) containing a coloring agent or a magnetic powder, and a powdery additive. The powdery additive has organic resin particles-(B) having peaks respectively in a region of particles diameters of 20 m.mu. to 200 m.mu. and a region of particle diameters of 300 m.mu. to 800 m.mu. in their particle size distribution, and the larger-diameters particles included in the region of particle diameters of 300 m.mu. to 800 m.mu. being contained in an amount of from 2% by weight to 20% by weight.

Abstract: The toner for developing an electrostatic image, excellent in any environmental conditions, comprises the colorant-containing resin particles and at least one kind of fine titanium oxide powder which has been made hydrophobic by treating in an aqueous medium; the fine titanium oxide powder has an average particle diameter of from 0.001 .mu.m to 0.2 .mu.m and a hydrophobicity of from 20% to 80%.

Abstract: A carrier for electrophotography has carrier particles. The carrier has a 50% average particle diameter (D.sub.50) of from 15 .mu.m to 45 .mu.m and contains from 1% to 20% of carrier particles with a size smaller than 22 .mu.m, not more than 3% of carrier particles with a size smaller than 16 .mu.m, from 2% to 15% of carrier particles with a size of 62 .mu.m or larger, and not more than 2% of carrier particles with a size of 88 .mu.m or larger. The carrier has a specific surface area S.sub.1 as measured by an air-permeability method and a specific surface area S.sub.2 as calculated by the following expression:S.sub.2 =(6/.rho..D.sub.50).times.10.sup.4wherein .rho. is a specific gravity of carrier; satisfying the following condition:1.2.ltoreq.S.sub.1 /S.sub.2 .ltoreq.2.0.

Abstract: Four color toners of yellow, magenta, cyan and black, and four two-component developers containing the four color toners respectively in combination with a resin-coated ferrite carrier suitable for multi-color electrophotographic copying are provided Each of the four-color toners is strictly regulated in relation not only to the carrier but also to the other color toners. More specifically, each color toner is strictly controlled with respect to a particle size distribution, freeness from agglomeration, melting characteristics including heat-absorption peaks and apparent viscosity on melting, chromaticity, triboelectric chargeability and optical toner concentration detection characteristic. Because of the strict regulation of these various parameters, the resultant multi-color toner or developer system shows excellent performances at every stage of multi-color electrophotography including development, transfer and fixing (color-mixing) for a long period of successive copying.

Abstract: A developing apparatus includes a developer layer thickness regulating zone downstream of one of magnetic poles of a stationary magnet disposed inside a developing sleeve, with respect to the rotational direction of the sleeve. In the regulating zone, there are provided a magnetic member and a non-magnetic member to regulate the layer thickness of the developer containing magnetic carrier particles and toner particles on the sleeve. The magnetic member has a width of not less than 1 mm and not more than 10 mm and a thickness of not less than 0.2 mm and not more than 3 mm.

Abstract: Four color toners of yellow, magenta, cyan and black, and four two-component developers containing the four color toners respectively in combination with a resin-coated ferrite carrier suitable for multi-color electrophotographic copying are provided. Each of the four-color toners is strictly regulated in relation not only to the carrier but also to the other color toners. More specifically, each color toner is strictly controlled with respect to a particle size distribution, freeness from agglomeration, melting characteristics including heat-absorption peaks and apparent viscosity on melting, chromaticity, triboelectric chargeability and optical toner concentration detection characteristic. Because of the strict regulation of these various parameters, the resultant multi-color toner or developer system shows excellent performances at every stage of multi-color electrophotography including development, transfer and fixing (color-mixing) for a long period of successive copying.

Abstract: Four color toners of yellow, magenta, cyan and black, and four two-component developers containing the four color toners respectively in combination with a resin-coated ferrite carrier suitable for multi-color electrophotographic copying are provided. Each of the four-color toners is strictly regulated in relation not only to the carrier but also to the other color toners. More specifically, each color toner is strictly controlled with respect to a particle size distribution, freeness from agglomeration, melting characteristics including heat-absorption peaks and apparent viscosity on melting, chromaticity, triboelectric chargeability and optical toner concentration detection characteristic. Because of the strict regulation of these various parameters, the resultant multi-color toner or developer system shows excellent performances at every stage of multi-color electrophotography including development, transfer and fixing (color-mixing) for a long period of successive copying.

Abstract: A color toner, comprises non-magnetic resin particles containing a coloring agent and two types of inorganic oxide particles, wherein;particles of coloring agent have an average particle diameter D of 300 m.mu..ltoreq.D.ltoreq.800 m.mu. as determined by measurement of scattered-light intensity; coloring agent particles with a particle diameter of from (D-120) m.mu. to (D+120) m.mu. account for not less than 90% of the whole; coloring agent particles with a particle diameter of 169 m.mu. or less account for not more than 1.0%; and coloring agent particles with a particle diameter of 949 m.mu. or more account for not more than 0.5%;said color toner has a volume average diameter of from 6 to 10 .mu.m; colored resin particles with a particle diameter of 5 .mu.m or less are contained in a proportion of from 15 to 40% by number; colored resin particles with a particle diameter of from 12.7 to 16.0 .mu.m are contained in an amount of from 0.1 to 5.

Abstract: Four color toners of yellow, magenta, cyan and black, and four two-component developers containing the four color toners respectively in combination with a resin-coated ferrite carrier suitable for multi-color electrophotographic copying are provided. Each of the four-color toners is strictly regulated in relation not only to the carrier but also to the other color toners. More specifically, each color toner is strictly controlled with respect to a particle size distribution, freeness from agglomeration, melting characteristics including heat-absorption peaks and apparent viscosity on melting, chromaticity, triboelectric chargeability and optical toner concentration detection characteristic. Because of the strict regulation of these various parameters, the resultant multi-color toner or developer system shows excellent performances at every stage of multi-color electrophotography including development, transfer and fixing (color-mixing) for a long period of successive copying.

Abstract: A method of reverse development for depositing the toner particles to the light potential area of a photosensitive member. The developer used contains magnetic carrier particles and toner particles. An alternating electric field is formed in the developing position or zone. A relative volumetric ratio Q (%) of the magnetic carrier particles in the developing position satisfies 15.0.ltoreq.Q.ltoreq.28.0. The relative volumetric ratio is defined asQ=(M/h).times.(1/.rho.).times.C.sigma./(T+C)where M (g/cm.sup.2) is an amount of applied developer on a developing sleeve surface per unit area, h (cm) is a height of space in the developing position, .rho. (g/cm.sup.3) is a true density of the magnetic carrier particles, C/(T+C) (%) is a weight ratio of the carrier particles in the developer on the surface of the sleeve, and .sigma. is a ratio of a peripheral speed of the sleeve relative to the peripheral speed of the photosensitive member.

Abstract: An image forming method that includes the steps of providing a developer comprising at least colored resin particles, a fluidity improver having a specific chargeability and magnetic particles wherein the colored resin particles have a volume-average particle size of 4-10 microns and a specific volume-basis particle size distribution; supplying the developer to a surface of a developer-carrying member disposed opposite to a latent image-bearing member having thereon an electrostatic latent image; carrying the developer on the surface of the developer-carrying member; and developing the electrostatic latent image on the latent image-bearing member with the developer in a developing zone where the latent image-bearing member is disposed opposite to the developer-carrying member to form a toner image; wherein an alternating electric field comprising an AC component and a DC component is imparted to the developing zone under specific conditions.

Abstract: A negative latent image is formed on a photosensitive member comprising an organic photoconductive material. The negative latent image is developed with a positively chargeable developer containing positively chargeable fine silica particles adapted to the organic photosensitive member. The developed image is transferred to a transfer material and the residual toner on the photosensitive member is removed. Thus, copied images without fog can be obtained successively.

Abstract: A developer comprising colored resinous particles and inorganic fine particles having a BET specific surface area of 0.2 to 30 m.sup.2 /g as measured by nitrogen adsorption. The inorganic fine particles have an action of promoting removal of paper powder and other adherents during cleaning of the latent image-bearing member without sticking onto the latent image-bearing member. Accordingly, the developer containing the inorganic fine particles can give good images even after successive copying operation for a long term.

Abstract: A method for applying a toner comprising: forming, in a container containing a toner and magnetic particles for application of the toner, a magnetic brush of the magnetic particles; circulating the magnetic particles in the container; and forming a thin layer of the toner electrically charged on the toner carrying member; wherein the magnetic particles have a particle size distribution of 30 wt. % or more in the range of 150 to 200 mesh and 5 wt. % or less of under 250 mesh, and the weight ratio of the toner to the magnetic particles is from 5:95 to 50:50 in the region where the magnetic brush is formed.

Abstract: A method for applying a toner comprising: forming, in a container containing a toner and magnetic particles for application of the toner, a magnetic brush of the magnetic particles; circulating the magnetic particles in the container; forming a thin layer of the toner electrically charged on the toner carrying member, wherein the magnetic particles have been treated with a substance A having a position opposite to that of the toner in the triboelectric series with the material constituting at least the surface of the toner carrying member as the standard substance and with a substance B having a position between the substance A and the toner in the triboelectric series.