Abstract: In an electrophotographic apparatus, which forms a color image by transferring a plurality of toner images having different colors onto an image-receiving sheet so as to be stacked and fixed thereon, even in the case of carrying out an oil-less fixing process and allowing the process speed to vary within wide range, the present invention provides a binder resin, toner and an electrophotographic apparatus which make it possible to achieve both superior fixing property and anti-offset property, and consequently to form a color image with high color reproducibility and high quality.

Abstract: An electrophotographic photoreceptor including at least an electroconductive substrate; and a photosensitive layer overlying the electroconductive substrate and including at least a charge generation layer; a charge transport layer; and a protective layer including a filler, wherein the filler is dispersed in the protective layer so as to occupy an area of from 3 to 5% of a cross section of the protective layer; the filler has particle diameter distribution having a peak at a diameter of from 0.2 to 0.3 &mgr;m; and the particles of the filler having a particle diameter of not less than 0.3 &mgr;m occupies an area of from 10 to 30% of the area of all the filler in the cross section of the protective layer.

Abstract: The tribo-electro static charge is stabilized by treating the surface of the metallic-oxide fine powders such as a silica powder, using the mixed solution which consists of a specific silane coupling agent containing primary amino group, other silane coupling agent containing amino group and the hydrophobic agent The powder such as silica has the small charge variation with time, and is suitable as the additive of the powder coatings or the electrophotographic toner.

Abstract: An electrophotographic photoconductor having an electroconductive support, and a photoconductive layer formed on the support and having an outwardly facing surface. The photoconductive layer includes a charge transporting material, a charge generating material and an inorganic filler including &agr;-alumina, wherein the concentration of the inorganic filler in the photoconductive layer decreases stepwise or continuously in the direction from the outwardly facing surface thereof to the opposite surface thereof.

Abstract: A photoreceptor for forming an electrostatic latent image is disclosed. The photoreceptor comprises a photosensitive layer and a resin layer wherein a resin of the resin layer comprises an organic polymer component, siloxane component and charge transportable component.

Abstract: A toner having a good chargeability stable against an environmental change is formed of toner particles each comprising at least a binder resin, a colorant, a release agent and a sulfur-containing polymer, and an external additive. The toner particles contain 100 to 30,000 ppm by weight thereof of at least one stabilizer element selected from the group consisting of magnesium, calcium, barium, zinc, aluminum and phosphorus. The toner particles may preferably be produced by suspension polymerization of a monomer composition containing the sulfur-containing polymer in an aqueous medium containing a dispersion stabilizer having the stabilizer element.

Abstract: Provided is an image forming method capable of forming an image at a high speed, simultaneously performing a low temperature fusing property and hot offset resistance and controlling gloss. The image forming method includes a developing step of forming a toner image by developing an electrostatic latent image formed on a latent image holding member by a developer containing at least a toner, a transferring step of forming a transfer image by transferring the toner image formed on the latent image holding member onto a transfer material, and a fusing step of fusing the toner image transferred on the transfer material. In the image forming method, the toner contains at least a colorant and a binder resin in which a principal component is a crystalline resin and the fusing step is performed by a fusing apparatus having a heat-fixing roll and an endless belt.

Abstract: Disclosed is a toner comprising particles of a resin and an optional colorant, said toner particles having coated thereon a polythiophene. Another embodiment of the present invention is directed to a process which comprises (a) generating an electrostatic latent image on an imaging member, and (b) developing the latent image by contacting the imaging member with charged toner particles comprising a resin and an optional colorant, said toner particles having coated thereon a polythiophene.

Abstract: A method is provided for manufacturing a master batch pigment for a toner, including the steps of mixing a dry pigment powder, a binder resin and water to prepare a mixture thereof; and kneading the mixture upon application of heat to prepare the master batch pigment, wherein the master batch pigment has a weight loss of from 0.01 to 1.0% when heated at 110° C. for 2 hrs.

Abstract: A toner for use in a color electrophotographic system ensures a sufficient offset resistance without oil being supplied, and meets requirements for color development, transparency and durability to withstand commercial use. The toner for an electrophotographic system has a resin 1 consisting of two or more resin mixtures having a different degree of crosslinking, the overall occupancy rate of mold releasing agent 3 present as a domain in one particle of the toner is 1 to 10%, and the average dispersion diameter of the mold releasing agent is 10 to 50% of the toner particle diameter.

Abstract: A toner composition includes toner particles formed of a resin and a colorant; and one or more external additives, at least one of the external additives including polymeric particles, applied to a surface of the toner particles. The polymeric particles include a polymer selected from polymethylmethacrylate, modified polymethylmethacrylate, halogenated polymethylmethacrylates, and mixtures thereof.

Abstract: A toner composition is provided wherein by adding aliphatic lower molecular weight compounds which are partly or completely compatible with the binder resin(s), the melt viscosity of the toner composition can be lowered while the glass transition temperature (Tg) is more or less constant. Inclusion of these adding aliphatic lower molecular weight compounds, having a number average molecular weight, as measured by GPC in toluene, of from 500 to 3,000, results in toner compositions with a better adhesion and gloss and still an acceptable level of FOT and hot-offset. Also provide is a method for fixing toner images on a substrate.

Abstract: A toner for development of electrostatic images, comprising at least a binder resin, a colorant and a charge control agent, wherein the charge control agent contains a positive charge control resin (A) composed of a polymer having a weight average molecular weight of 1,000 to 100,000 and a functional group which brings positively charging ability, and a negative charge control resin (B) composed of a polymer having a weight average molecular weight of 1,000 to 100,000 and a functional group which brings negatively charging ability. The toner is excellent in flowability, shelf stability and charge properties, and provides images excellent in image quality.

Abstract: A charge-controlling agent comprising a polyamine having a repeating structure represented by the following general formula (I): The symbols in the formula are defined in the specification. Also disclosed is a toner using the charge-controlling agent.

Abstract: A full color image forming method including the steps of developing an electrostatic latent image formed on an image bearing member with a color toner to form a color toner image thereon; first transferring the color developer including a color toner image onto an endless intermediate transfer material while applying a developing bias thereto; repeating the above-mentioned steps a plurality of times using a plurality of different color developers to form a full color toner image on the intermediate transfer material; and second transferring the full color image onto a receiving material, wherein a weight of each of the color toner images formed on the image bearing member is from about 0.4 mg/cm2 to about 1.5 mg/cm2, and each of the color developers has a charge quantity not less than 15 &mgr;C/g in an absolute value, and wherein the following relationship is satisfied with respect to each of the first color toner transferring steps: 5.4×Q1+90<Vb−V1<5.

Abstract: This invention relates to magnetite particles with a mean particle size of 0.1 to 0.3 &mgr;m, a specific surface area of 6 to 9 m2/g, a coercive force of 80 to 110 Oe, a residual magnetization of 13 to 20 nTm3/g, a pH of 7 to 10 and a bulk density of 0.6 to 0.9 g/cm3, by heating an aqueous solution of an alkaline component under inert gas, to a precipitation temperature of 65-85° C., adding iron (II) and iron (III) components and oxidizing the suspension with an oxidizing agent at a speed of 7-25 mol % Fe (II)/h.

Abstract: An electrophotographic photoreceptor including at least an electroconductive substrate, a photosensitive layer formed on the substrate and a protective layer formed on the photosensitive layer and including a binder resin, wherein when a solution in which the binder resin is dissolved in an organic solvent incompatible with water is mixed with deionized water having an electroconductivity not greater than 1 &mgr;S/cm and substantially the same weight as that of the solvent while agitating, the water has an electroconductivity not greater than 2 &mgr;S/cm.

Abstract: An electrophotographic photosensitive member has, in this order, a support, a photosensitive layer and a protective layer. The thickness d (&mgr;m) of the protective layer, the universal hardness Hu-1 (N/mm2) of the protective layer, and the universal hardness Hu-2 (N/mm2) of the photosensitive layer after peeling off the protective layer satisfy the following expression (1): 5.8×d+Hu-2≦Hu-1≦−2.45×d2+44.4×d+Hu-2  (1). Also disclosed are a process cartridge and an electrophotographic apparatus which have the above electrophotographic photosensitive member.

Abstract: A toner composition that permits printing of clear-cut and high image quality without developing a fog or a blur is provided.

Abstract: A color toner to which flash light is applied and is fixed on a recording medium at least includes a binding resin, a colorant, and a infrared absorbent. PAS intensity thereof obtained from integration of infrared PAS spectrum obtained based on photoacoustic spectroscopy (PAS) analytical measurement through a range between 800 and 2000 nm is in a range between 0.01 and 0.2 assuming that the value of carbon black is 1.