Abstract: The electrophotographic toner for negative charging according to the present invention is characterized in that an acrylamide copolymer-containing sulfonic acid group is used as a charge-controlling agent for negative charging and a quaternary ammonium salt having an oxyacid anion is used as a charge-controlling assistant in combination with the charge-controlling agent. This quaternary ammonium salt used as the assistant is incompatible with a fixing resin but dispersible therein. Therefore, the toner of the present invention provides a sharp distribution of the charge quantity, and formation of a highly charged toner having no contribution to development or a lowly charged toner causing scattering of the toner can be effectively prevented.

Abstract: The electrophotographic toner for negative charging according to the present invention is characterized in that a quaternary ammonium salt having an oxyacid anion is used as a charge-controlling assistant in combination with a charge-controlling agent for negative charging. This quaternary ammonium salt used as the assistant is incompatible with a fixing resin but dispersible therein. Therefore, the toner of the present invention provides a sharp distribution of the charge quantity, and formation of a highly charged toner having no contribution to development or a lowly charged toner causing scattering of the toner can be effectively prevented.

Abstract: Disclosed is a developing process using a two-component type magnetic developer, where the main pole of developing magnetic poles in the developing sleeve is arranged upstream of the position, where a photosensitive drum becomes closest to the developing sleeve, in the rotation direction of the developing sleeve, this closest position between the drum and the developing sleeve is included in a region where the flux density in the magnetic force distribution of the main pole decreases toward the downstream side in the rotation direction of the sleeve, an alternating current voltage is applied between the developing sleeve and the drum to form an alternating electric field between the highest voltage and lowest voltage of the electrostatic latent image and in this state the development is carried out. According to this process, the conditions required for the supply of the developer are considerably moderated and an image having a high quality can be advantageously obtained.

Abstract: Disclosed is a developing process using a two-component type developer comprising a magnetic carrier and a toner, in which the developing conditions of the two-component type developer, that is, the composition and density of the developer in a distance between a photosensitive material drum and a developing sleeve (or a distance of a developing zone), are specified based on relations of these conditions to this distance. According to this developing process, the flowability of the developer in the developing zone is improved, and furthermore, the transferability of the toner to the photosensitive material drum is improved.

Abstract: A color toner forming a developed image to be transferred to a transparent sheet by a known electrophotographic method, the refractive index of said color toner being smaller than that of said transparent sheet, but greater than that of the air.

Abstract: Disclosed is a negatively chargeable blue toner comprising a fixing resin binder and an indanthrone dye as a coloring and charge controlling agent. The indanthrone dye as the coloring and charge controlling agent may be used advantageously not only singly but also in combination with a halogen-substituted copper phthalocyanine pigment.

Abstract: A charged image on a photosensitive layer is developed with a toner containing a releasing agent and a hydroxycarboxylic acid complex salt to form a toner image. The toner image is then transferred to a receptor sheet and fixed to it. The use of a toner containing a specific hydroxycarboxylic acid complex salt brings about a marked advantage of widening a non-offset region to a higher temperature without impairing the antiblocking property, flowability and heat resistance of the toner.

Abstract: A developing process for two-colored electrophotography comprising: (1) charging the surface of a photoreceptor having a conductive substrate and two photosensitive layers successively formed on the conductive substrate, said photosensitive layers having different spectral sensitivities, (2) charging the surface of said photoreceptor with a different polarity from the charging polarity in step (1), (3) exposing a two-colored original to form electrostatic latent images, which have different polarities corresponding to the two-colored original, on the surface of said photoreceptor, (4) transferring a first color toner charged with a different polarity from the charging polarity of one of the electrostatic latent images on said electrostatic latent image to develop said electrostatic latent image iwth the first color toner, (5) exposing the surface of said photoreceptor to eliminate electric charges with the same polarity as the first color toner which are induced on the surface of said photoreceptor in the vic