Abstract: To provide toner which is capable of suppressing consuming amount of toner and preventing cleaning failure, and even when a high speed printing machine is used, can reduce a problem of e.g. fogging in a long-term use and is excellent in image stability. A toner for developing an electrostatic charge image, which comprises toner matrix particles formed in an aqueous medium, wherein the toner has a volume median diameter (Dv50) of from 4.0 ?m to 7.0 ?m; and the relationship between the volume median diameter (Dv50) and the percentage in number (Dns) of toner particles having a particle diameter of from 2.00 ?m to 3.56 ?m satisfies the following formula (1): Dns?0.233EXP(17.3/Dv50)??(1) where Dv50 is the volume median diameter (?m) of the toner, and Dns is the percentage in number of toner particles having a particle diameter of from 2.00 ?m to 3.56 ?m.

Abstract: To provide an image forming apparatus which is able to improve image quality while suppressing soiling of image white parts, scattering in the apparatus, streaks, fading, etc. due to non-uniformity in the particle size distribution of a toner or mismatching between a toner and a photoreceptor, and which has good cleaning properties, and even when a high speed printing machine is used, is able to reduce a problem of soiling, etc. in long-term use and provide excellent image stability.

Abstract: To provide a toner excellent in the image stability, whereby the image quality can be improved while suppressing soiling of image white parts, residual images (ghosts), fading (blotted image follow-up properties), etc., cleaning properties are good, and even when a high speed printing machine is used, it is possible to reduce a problem of soiling, etc. An image forming apparatus comprising an electrophotographic photoreceptor and a toner for developing an electrostatic charge image, wherein a photosensitive layer of the electrophotographic photoreceptor contains a resin having a structural unit represented by the following formula (A); the toner for developing an electrostatic charge image is a toner for developing an electrostatic charge image containing toner matrix particles formed in an aqueous medium; the toner has a volume median diameter (Dv50) of from 4.0 ?m to 7.

Abstract: To provide an image forming apparatus which is capable of suppressing soiling of image white parts, residual images (ghosts), fading, etc. due to non-uniformity in the particle size distribution of a toner or mismatching between a toner and a photoreceptor and which is able to improve image quality, provides good fixing properties and cleaning properties with little fogging or dot missing, presents good reproducibility of fine lines, and even when a high speed printing machine is used, can reduce a problem of e.g. soiling in a long-term use and presents excellent image stability.

Abstract: To provide a process for efficiently producing a toner for developing an electrostatic charge image, which is scarcely susceptible to aggregation of the toner and free from blocking during the storage or from soiling the image forming apparatus and which is excellent in image characteristics.

Abstract: A copolymer having repeating units of the following formula (I) and repeating units of the formula (II), wherein the ration of (I) to (II) is within a range of from 10:90 to 90:10 by weight ratio, and the number average molecular weight is at least 1,000, or the intrinsic viscosity .eta..sub.inh is at least 0.02: ##STR1## wherein A is a polyester unit having a polymerization degree of from 2 to 200, R.sup.3 is a bivalent organic group having an ester, urethane or ketone bond, and R.sup.4 is a hydrogen atom or a methyl group, ##STR2## wherein R.sup.5 is a hydrogen atom or a methyl group, and X is a substituent having functionality.

Abstract: Disclosed herein is a process for producing an azo group-containing polymer comprising polycondensing a compound having an azo group in the main molecular chain and an alcoholic hydroxyl group, phenolic hydroxyl group, imino group or amino group at both ends thereof with a dicarboxylic acid chloride or a carbonate precursor except the polycondensation of a compound having an azo group in the main molecular chain and an alcoholic hydroxyl group at both ends thereof with a carbonate precursor.