Abstract: A two-component type developer comprising an electroscopic fixable toner containing, as the coloring pigment, carbon black having a coloring power of 100 to 120 and a magnetic carrier is sued for developing electrostatic latent images formed on a photosensitive plate in correspondence to an imitation original and an original, and the image density of the toner image corresponding to the imitation original is detected and the toner concentration in the developer is controlled based on the detected image density. According to this development process, the toner concentration in the developer can be maintained within an optimum range based on the optical density of the toner image formed on the photosensitive plate in correspondence to the imitation original.

Abstract: A developing process for electrophotography comprising: (1) feeding a developer to a non-magnetic sleeve, said developer consisting of an insulative and non-magnetic toner charged with an electrical polarity and a magnetic carrier, (2) maintaining said developer on the sleeve, (3) removing said carrier from said developer on the sleeve to leave said non-magnetic toner on the sleeve, and (4) transferring said non-magnetic toner from the sleeve to an electrostatic latent image on the surface of a photoreceptor.

Abstract: A toner for electrophotography, comprising an azoic pigment having a silica core as a coloring component, said azoic pigment comprising a core of a fine powder of silica and a coating of a mono- or polyazoic dye chemically bound to the surface of the silica core through an aminosilane coupling agent.

Abstract: Disclosed is a one-component type red color magnetic developer having a self-electroscopic property, which comprises particles prepared from a kneaded composition comprising 100 parts by weight of a magnetic powder composed mainly of ocherous gamma-type diiron trioxide, 2.5 to 30 parts by weight of a red azo pigment and 40 to 200 parts by weight of a binder resin, wherein a fixed image of the particles is measured by a color difference meter, the value x is from 0.51 to 0.73, the value y is from 0.22 to 0.40 and the value Y is from 5 to 65%.

Abstract: An electrophotographic method for the formation of two-colored images comprising: (1) uniformly charging the surface of a photoreceptor having a conductive substance and a photoconductive layer formed on the conductive substance, said photoconductive layer being sensitive to a first color, (2) exposing a two-colored original, to form on said photoconductive layer an electrostatic latent image, which corresponds to a second color region in the original, with the same polarity as the electric charges on the surface of said photoconductive layer, (3) subjecting the surface of said photoreceptor to a reversal development treatment by the use of a photoconductive color toner charged with the same polarity as the electric charges constituting said electrostatic latent image, to develop the non-charged region with the photoconductive color toner, (4) subjecting said electrostatic latent image to a normal development treatment by the use of an insulative toner having a color different from the color of said photocond

Abstract: Disclosed is a dry magnetic developer consisting essentially of a particulate shaped article of a composition comprising a binder resin medium and a powdery magnetic material dispersed in the binder resin medium, wherein said composition is composed of a non-pulverizing agglomerate of cubic particles, and particles having a number average particle size of 1 to 10 microns, as measured by an electron microscope, are incorporated as the powdery magnetic material.This magnetic developer is excellent in the image sharpness, the resolving power and the half tone-reproducing property, and is especially effective for developing a positively charged latent image which is formed on a p-type photosensitive plate such as a selenium photosensitive plate or a photosensitive plate comprising an organic photoconductor layer.