Abstract: In an electrophotographic developer and a process for forming an image, an electrophotographic toner used therein contains spherical toner parent particles and two or more kinds of inorganic particles having different average particle diameters, at least one kind of the inorganic fine particles being spherical particles having an average primary particle diameter of about 80 to 300 nm, and the inorganic particles containing the spherical particles being attached to the toner parent particles to provide a structure satisfying the following conditions (1) and (2): (1) the spherical particles have a coverage on a surface of the toner parent particles of about 20% or more; and (2) a proportion of the inorganic particles that are separated from the toner parent particles upon dispersing the toner in an aqueous solution is about 35% or less of a total addition amount of the inorganic particles.

Abstract: An electrophotographic developer is provided that attains improvement in reliability by improvement in cleaning property and reduction in wear of a photoreceptor in a well-balanced manner without impairing high transfer efficiency and high image quality of a spherical toner. The electrophotographic developer contains a toner and a carrier, the toner containing spherical colored particles having an average shape factor (ML2/A) of about from 100 to 135 and irregular-shaped non-colored particles having a volume average particle diameter of about from 1 to 10 &mgr;m, a charge distribution of the developer having a peak value Q/Ma ascribable to the spherical colored particles and a peak value Q/Mb ascribable to the irregular-shaped non-colored particles, and the peak value Q/Ma and the peak value Q/Mb satisfying both the following formulae (1) and (2): 20 &mgr;C/g≦|Q/Ma|≦85 &mgr;C/g  (1) −0.7 Q/Ma≦Q/Mb≦0.5 Q/Ma  (2).

Abstract: In an electrophotographic developer and a process for forming an image, an electrophotographic toner used therein contains spherical toner parent particles and two or more kinds of inorganic particles having different average particle diameters, at least one kind of the inorganic fine particles being spherical particles having an average primary particle diameter of about 80 to 300 nm, and the inorganic particles containing the spherical particles being attached to the toner parent particles to provide a structure satisfying the following conditions (1) and (2):

Abstract: An electrophotographic developer is provided that attains improvement in reliability by improvement in cleaning property and reduction in wear of a photoreceptor in a well-balanced manner without impairing high transfer efficiency and high image quality of a spherical toner.

Abstract: The present invention provides toner for an electrostatic latent image developer, said toner being excellent in fluidity, chargeability, developability, transferability, and freedom from fogging on a photoreceptor and contamination of the interior of a developing device. The toner for an electrostatic latent image developer comprises spherical toner particles characterized by a shape index ML.sup.2 /A of less than 125 and has a correlation coefficient between X.sup.2/3 and Y, obtained by linear regression with respect to a straight line which passes through the origin of coordinate axes, of more than 0.6 where X is the light emitting voltage due to the carbon derived from the binder resin of the toner particles and Y is the light emitting voltage due to the element derived from the external additive.

Abstract: A toner for electrophotography comprising a colorant and a binder resin, wherein the toner further contains an image reinforcing agent, is disclosed. The reinforcing agent is preferably a high melt viscosity resin whose weight average molecular weight is 300 to 3000 and whose melt viscosity .eta. at 140.degree. C. is 10.sup.3 to 10.sup.6 (Pa.multidot.s). A developer for electrophotography containing a carrier and a toner comprising of a colorant and a binder resin, wherein the toner contains an image reinforcing agent, is also disclosed.

Abstract: A toner comprising toner particles comprising a binder resin and a colorant, wherein the toner particles have a number average particle diameter of from 3 to 10 .mu.m and satisfy relationship (1) or (2):M.sub.50 (b)>M.sub.50 (a)>M.sub.50 (c) (1)M.sub.50 (b)<M.sub.50 (a)<M.sub.50 (c) (2)wherein M.sub.50 (a) is an average shape index at a number average particle diameter D.sub.50 which is calculated from cumulative 50% particles counting from the larger diameter side, M.sub.50 (b) is an average shape index at a number average particle diameter D.sub.16 which is calculated from cumulative 16% particles counting from the larger diameter side, and M.sub.50 (c) is an average shape index at a number average particle diameter D.sub.84 which is calculated from cumulative 84% particles counting from the larger diameter side.

Abstract: The present invention provides a carrier for developer of an electrostatic latent image and related technologies. The carrier is excellent in the ability to impart charge suitably and stably to toner and has a structure durable enough to maintain the ability for a long period of time such that the structure can prevent the toner from being adhered onto the carrier surface for a long period of time.The carrier comprises a core covered with a resin coating layer containing resin particles and an electroconductive fine powder in the form of a dispersion in a matrix resin.The carrier can be produced by a method comprising the steps of preparing a coating solution by placing materials in a solvent which can dissolve the matrix resin, but cannot dissolve the resin particles, dispersing the particles of the resin, applying the solution to a core and removing the solvent. A high-quality image can be formed by use of the developer comprising the carrier and the toner.

Abstract: A carrier for developing an electrostatic latent image comprising a core material coated with a resin layer, wherein the F/N ratio of the surface of the resin layer ranges from 1 to 20. It is desirable that the resin layer include resin particles containing a nitrogen atom, that the average particle diameter of the nitrogen-atom-containing resin be in a range from 0.1 to 2 .mu.m, that the thickness of the resin layer be in a range from 0.1 to 10 .mu.m, that the resin layer include an electroconductive material which is in a condition to be dispersed in the resin layer, that the electroconductive material be made of carbon black, and that the average particle diameter of the carrier for developing an electrostatic latent image be in a range from 30 to 150 .mu.m. The carrier for developing an electrostatic latent image, which is long-lived, provided with a charging capability unchanged over time, and is capable of effectively preventing fogging are provided.

Abstract: The present invention provides a long-life carrier for developing an electrostatic latent image to be used in such field of applications as electrostatic photography and electrostatic recording, a developer of an electrostatic latent image utilizing said carrier, a method for forming an image and an image forming apparatus by using said developer. By use of the foregoing qualities, a high-quality image can be obtained.

Abstract: A toner for developing an electrostatic latent image, which comprises toner particles and treated titanium oxide fine particles obtained by coating titanium oxide fine particles with 0.1 to 2.0% by weight, in terms of Al.sub.2 O.sub.3, of aluminum or Al.sub.2 O.sub.3 and further subjecting the coated particles to surface treatment with a treating agent.

Abstract: A image formation process comprising the steps of forming an electrostatic latent image on an electrostatic latent image carrier, developing the electrostatic latent image with a developer to provide a toner image, transferring the toner image to a transfer material, and heat-fixing the toner image on the transfer material, wherein the developer comprises a toner for developing electrostatic latent images comprising a binder, a colorant, and 1 to 30% by weight of a lubricant which comprises a modified polyethylene wax which is obtained by homopolymerizing ethylene or copolymerizing ethylene and an .alpha.