Abstract: A developer for developing an electrostatic latent image, including a carrier which includes core particles, and a surface layer surrounding each of the core particles and containing an acrylic resin binder; and a toner which includes toner particles and an external additive of inorganic or organic fine particles present on each of the toner particles. Each of the toner particles comprises a colorant, a matrix of a first resin, and a plurality of domains of a second resin dispersed in the matrix and containing a wax. The first resin is substantially free of tetrahydrofuran insoluble matters and has a weight average molecular weight of 3,000 to 90,000.

Abstract: A toner having a half melting temperature not greater than 115 ° C. has good fixability without filming, even in an image forming method using a non-contact fixing method; has good fixability and color reproducibility, even in an image forming method reproducing multi-colored images by combining two or more toner layers of different color; has good heat resistance without impairing fixability and color reproducibility; and produces high quality images without impairing fixability and color reproducibility.

Abstract: A magnetic toner with a negative polarity for developing latent electrostatic images is made of toner particles, each toner particle containing a binder resin, a magnetic powder, and a charge control agent, the surface of the magnetic toner satisfying the relationship of 2×10−7≦C/Sw≦10×10−7, provided C≦8×10−3, wherein C is an amount (g/g) of the charge control agent dissolved in a solvent comprising water and methanol, and Sw is a specific surface area (cm2/cm3) of the toner particles determined from a weight-average particle diameter of the toner particles. An image forming apparatus has an electrostatic image bearing member, and a unit for developing the electrostatic image with the above magnetic toner, the unit having a developer holding member provided with a magnet, and a developer container.

Abstract: An external additive for a toner, having an average primary particle diameter not greater than 100 nm and including at least inorganic fine particles and a hydrophobizing agent applied to the surface of the inorganic fine particles, wherein after the external additive is treated with chloroform, pyrolysates of the residual components include a compound having at least one structure selected from organopolysiloxane structures and ring siloxane structures.

Abstract: A toner including a binder resin; a colorant; and an external additive, wherein the external additive includes a particulate inorganic material, and a silicone oil, wherein the silicone oil is present on the particulate inorganic material in an amount of Ws by weight and present as a free silicone oil in an amount of Wfs by weight, and a free silicone degree defined as a ratio Wfs/Ws is from 10 to 70%.

Abstract: A magnetic toner with a negative polarity for developing latent electrostatic images is made of toner particles, each toner particle containing a binder resin, a magnetic powder, and a charge control agent, the surface of the magnetic toner satisfying the relationship of 2×10−7≦C/Sw≦10×10−7, provided C≦8×10−3, wherein C is an amount (g/g) of the charge control agent dissolved in a solvent comprising water and methanol, and Sw is a specific surface area (cm2/cm3) of the toner particles determined from a weight-average particle diameter of the toner particles. An image forming apparatus has an electrostatic image bearing member, and a unit for developing the electrostatic image with the above magnetic toner, the unit having a developer holding member provided with a magnet, and a developer container.

Abstract: An external additive for a toner, which has an average particle diameter not greater than 100 nm and includes an inorganic particulate material; and a hydrophobizing agent which is present on the inorganic particulate material in an amount of Ws by weight and present as a free hydrophobizing agent in an amount of Wf by weight, wherein a residual ratio defined as a ratio {Ws/(Ws+Wf)}×100 is from 40 to 98.5%, and wherein at least one of a compound having an organopolysiloxane structure and a compound having a ring siloxane structure is detected when the external additive is analyzed by a pyrolysis gas chromatography mass spectroscopy method after the external additive is washed with chloroform.

Abstract: A toner including a resin and a colorant which is dispersed in the toner and which has an average major particle diameter not greater than about 0.5 &mgr;m, wherein the following relationships are satisfied: Ta≦100 (° C.), and (Tb−Ta)≧7.0 (° C.), wherein Ta represents a temperature at which the toner has a melt viscosity of 50,000 Pa·sec and Tb represents a temperature at which the toner has a melt viscosity of 5,000 Pa·sec.

Abstract: A method for forming a full color image including: forming at least yellow, magenta and cyan color toner images on a receiving material to form a full color image thereon; and fixing the full color image upon application of heat thereto while not contacting the full color image, wherein each of the yellow, magenta and cyan color toner images includes a binder resin and a pigment, wherein the yellow color toner includes a benzimidazolone pigment, the magenta color toner includes at least one of Naphthol Carmine F6B and a combination of Naphthol Carmine F6B and Naphthol Carmine FBB, and the cyan color toner includes &bgr; copper phthalocyanine, and wherein the yellow color toner image has a position closer to the receiving material than any other color toner image when two or more of the color toner images including the yellow color toner image are overlaid.

Abstract: A toner including a binder resin; a colorant; and an external additive, wherein the external additive includes a particulate inorganic material, and a silicone oil, wherein the silicone oil is present on the particulate inorganic material in an amount of Ws by weight and present as a free silicone oil in an amount of Wfs by weight, and a free silicone degree defined as a ratio Wfs/Ws is from 10 to 70%.

Abstract: A two-component developer includes a magnetic carrier including magnetic carrier particles with an average particle diameter of 35 &mgr;m to 100 &mgr;m, and a toner including toner particles with a weight-average particle diameter of 6.0 &mgr;m to 11.5 &mgr;m, to which at least one additive is externally added thereto in an amount of 0.3 to 1.5 wt. % to the toner, the toner particles including (a) toner particles with a particle diameter of 5 &mgr;m or less with a content ratio of 15% or less by number, and (b) toner particles with such a particle diameter that is two times or greater than the weight-average particle diameter of the toner particles with a content ratio of 5% or less by volume, the toner particles satisfying a relationship of 0.60≦D25/D75≦0.85 as defined in the specification. A container in which the two-component developer is contained, and an electrophotographic image formation apparatus in which the container is incorporated are proposed.

Abstract: A toner is made or toner particles which contains a binder resin and a coloring agent, wherein the toner particles have a weight-average particle size in a range of 6.0 to 11.5 &mgr;m, and contains toner particles (a) with a particle diameter of 5 &mgr;m or less in a content ratio of 1 to 15% by number, and toner particles (b) with a particle diameter of twice or more the weight-average particle size in a content ratio of 5 wt % or less, and the number-average particle size D25 and the number-average particle size D75 respectively obtained when the cumulative number of the toner particles reaches 25% and 75% at the measurement of a cumulative toner particle distribution by number thereof are in the relationship of 0.60≦D25/D75≦0.95. A two-component developer includes the above-mentioned toner and a carrier.

Abstract: In an electrophotographic or electrostatic image forming device, the toner concentration of a two-component developer, i.e., a mixture of toner and carrier is measured on the basis of an output of a magnetic bridge type concentration sensor responsive to the magnetic permeability of the developer. The sensor has a surface whose mean roughness along the center line is less than 0.4 .mu.m Ra.