Nippon Zeon Company, Ltd.

Jun Sakai

Jun Hasegawa

Tokudai Ogawa

Takahiro Takasaki

Noboru Yanagida

Makoto Watanabe

Fumio Yamada

A monomer for a shell or a mixture of at least two monomers for a shell was suspension polymerized in the presence of core particles and a polymerization initiator to obtain polymer particles, wherein said core particles are formed of a polymer obtained by polymerization of a monomer for a core or a mixture of at least two monomers for a core and containing a colorant, wherein said monomer for a shell or mixture of monomers for a shell is one which gives upon polymerization a polymer having a glass transition temperature higher than that of the polymer forming the core particle, and wherein said polymerization initiator is represented by the following formula 1: ##STR1## wherein X.sup.1, X.sup.2, X.sup.3 and X.sup.4 independently represent oxygen atom, sulfur atom, &gt;NR (wherein R is hydrogen atom, alkyl group, or group); R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5 and R.sup.6 independently represent alkyl group, aryl group, or alkyl or aryl group having at least one substituent which is --OR, --OH, --NHR, or --NR.sub.2 (wherein R is alkyl group or aryl group), and n and m independently represent an integer of 1 to 10. An outer additive was applied on the polymer particle to obtain a polymerized toner. This polymerized toner has low fixing temperature, excellent overhead projector transparency, good shelf stability, and exhibiting a less pronounced reduction in electric charge under conditions of high humidity and high temperature.

Polymerized toner

Disclosed herein are a polymerized toner of core-shell structure, comprising core particles composed of colored polymer particles having a volume average particle diameter (dv) of 0.5-20 .mu.m and a ratio (dv/dp) of the volume average particle diameter (dv) to a number average particle diameter (dp) of at most 1.7, and shell which is formed of a polymer layer having an average film thickness of 0.001-0.1 .mu.m and covers each of the core particles, and a production process thereof.

Process for producing polymerized toner

Polymerized toner and production process thereof

Production process of toner for development of electrostatic latent image

Growing community of inventors

Kanagawa, Japan

Jun Sakai