Abstract: A toner for developing electrostatic images, comprises a binder resin and a colorant, wherein the binder resin comprises a vinyl copolymer having an acid anhydride group, and the binder resin has a total acid value (A) of 2-100 mgKOH/g and a total acid value (B) attributable to acid anhydride group of below 6 mgKOH/g so that [(B)/(A)].times.100 is 60% or less. Because the binder resin has a specified acid value partly attributable to acid anhydride group, the toner is provided with an adequate balance between chargeability and dischargeability, so that the toner shows a stable performance under various environmental conditions. The toner is particularly advantageously constituted as a magnetic toner of fine particle sizes suitably used under application of unsymmetrical alternating bias electric field.

Abstract: A positively chargeable toner for developing electrostatic images in electrophotography, electrostatic recording, electrostatic printing, etc. The toner contains a binder resin, a colorant or magnetic material, and a diorganotin borate. Because of the diorganotin borate contained, the toner has a uniform and stable triboelectric chargeability. The improved properties of the toner are enhanced when it is combined with positively chargeable fine silica powder.

Abstract: A method for developing electrostatic latent images formed on an electrostatic image bearing member, particularly by a thin and uniform layer of toner formed on a toner carrying member. In the method, good images can be stably obtained by controlling the gross electric charge per unit area within the range of 3.times.10.sup.-10 to 10.sup.-7 coulomb/cm.sup.2 in terms of the absolute value thereof and the packing density within the range of 0.1 to 0.6 g/cm.sup.3 with respect to the toner layer carried on the toner carrying member at the developing station.

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; 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.

Abstract: A developer contains a silicone oil which has an amine on side chain thereof, a development process comprises arranging a member holding an electrostatic image on the surface and a member for carrying a toner on the surface and a fixing method comprises contacting a toner image on an image-supporting member with a heated roller, said toner image being formed of a toner which contains a silicone oil having an amine on side chain thereof and has an MI of 0.01-10 g/10 min.

Abstract: A process for producing a toner includes melt-blending at least a colorant and a polymer and finely pulverizing the resulting blend after cooling, wherein the polymer is a crosslinked resin having a ratio of weight-average molecular weight to number-average molecular weight (Mw/Mn) exceeding 4.0 and a melt index of 0.01-10 g/10 min. at 110.degree. C. under a load of 10 Kg and the polymer is further crosslinked to form gel during the melt-blending. The toner thus obtained exhibits a good fixability without offset phenomenon over a wide temperature range.

Abstract: A developing powder comprises a binder containing 50% by weight or more of a polymer having a gel content of 10% or less and prepared from a vinyl type monomer and a crosslinking agent monomer contained in an amount of 0.01-10% by weight based on the total weight of the monomers, and 0.1-5% by weight of an olefin homopolymer or copolymer having a melt viscosity at 140.degree. C. of 10-10.sup.6 cps.

Abstract: A thin layer of triboelectrically charged toner for developing an electrostatic latent image is formed by forming a magnetic brush of magnetic particles in a container containing the toner and the magnetic particles, and circulating the magnetic brush in the container on a toner carrying member. In this case, a uniform layer of toner adapted for development is obtained, if the magnetic particles have specific shape characteristics such that, where each magnetic particle is assumed to be circumscribed with a rectangular parallelopiped having edge length of a, b and c satisfying a.gtoreq.b.gtoreq.c with the proviso that all of a, b and c are not the same, the average of b/a is from 0.4 to 1.0 and the average of c/a is from 0.4 to 0.95.

Abstract: A magnetic toner comprises magnetic powders having a particle distribution that the particle size of 50% accumulated volume, the particle size of 25% accumulated volume and the particle size of 75% accumulated volume of the magnetic powders are 1.5-4.5.mu., 1.0-4.0.mu. and 2.5-6.0.mu., respectively. This magnetic toner can produce high density and clear images and further, can produce colorful images.

Abstract: A developing powder comprises a binder containing 50% by weight or more of a polymer having a gel content of 10% or less and prepared from a vinyl type monomer and a crosslinking agent monomer contained in an amount of 0.01-10% by weight based on the total weight of the monomers, and 0.1-5% by weight of an olefin homopolymer or copolymer having a melt viscosity at 140.degree. C. of 10-10.sup.6 cps.

Abstract: Red to sepia magnetic toners stable to heat and light which do not fade or discolor for a long period of time are prepared by incorporating a partially .alpha.-transformed .gamma.-Fe.sub.2 O.sub.3 as a component in a toner.

Abstract: A toner for development comprises a crosslinked vinyl polymer having a gel content of 50-99% and a crosslinked vinyl polymer having a gel content of 10-0%.

Abstract: A process for development comprises arranging an electrostatic image bearing member having electrostatic images on the surface and a developer carrying member at a predetermined space, an insulating magnetic developer containing 10-50% by weight of magnetic toner particles 20-35 microns in size being carried on the developer carrying member in a thickness thinner than the predetermined space, and transferring the insulating magnetic developer to the electrostatic image bearing member in the presence of a magnetic field.According to this process for development, there can be produced developed images of high fidelity, high density and high resolution and free from fog.