Toner with positive electricity for electronic photographing and its mfg. method

Abstract

Provided is an electrophotographic positively charged toner and a manufacturing method thereof, according to which even if after kneading, pulverization and classification the toner is made spherical by melting the surfaces of the particles in a hot air current, the charge control agent is not coated and hence the charging ability thereof is not reduced, and thus the toner has sufficient tribo-charging ability for good image formation, excellent transfer efficiency, and excellent charge build-up performance and excellent charge stability upon continuous printing. In the case of an electrophotographic positively charged toner comprising a core toner that has a binder resin, a wax, a colorant and a charge control agent as principal component materials thereof and has been spherified through heat treatment, and at least fine silica particles as an external additive, the charge control agent is made to contain a resin having a quaternary ammonium salt group as a functional group and a nigrosine dye.

Description

technical field [0001] The present invention relates to a toner for developing an electrostatic latent image used in an apparatus for forming an image by electrophotography, and particularly relates to a positively charged toner for electrophotography and a method for producing the same. Background technique [0002] In the development process, the toner used to develop the electrostatic latent image of the electrostatic copier, printer, etc. by electrophotography is sent to the static electricity on the surface of the photoreceptor formed by the charging, exposure and other processes in the previous process. on the latent image to make it a visible image. In the subsequent transfer process, after such a toner image is transferred from the surface of the photoreceptor to the transfer medium (used paper, etc.), it is fixed in the fixing process so that it can be printed on the transfer medium (used paper, etc.). ) is conveyed to paper in the form of a printed image. In gene...

AI Technical Summary

Problems solved by technology

[0017] However, in such a wet granulation method, impurities such as surfactants and polymerization initiators added during granulation tend to remain in the toner after granulation, often adversely affecting chargeability, insulation, etc.

In particular, the selectivity of resins is narrow due to the limitation of binder resins that can use the above-mentioned wet polymerization granulation method

A problem in which the degree of freedom of its molecular weight distribution is also limited

[0018] In addition, it is known that in the conventional dry pulverization method, the toner after kneading, pulverization and classification is introduced into the hot air flow, since the surface of the particles will melt and form a spherical shape, which solves the above-mentioned problems such as the decrease in fluidity, but this method The problem is that the charge amount of the toner decreases due to the spheroidization accompanying the melting of the toner surface as described above

That is, due to the melting of the surface of the toner, the charging regulator existing on the surface exposed is covered with the molten resin to lower the charging performance.

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