PURPOSE: To ensure high durability and stable triboelectric characteristics and to extend useful life by forming a coating layer made of a resin contg. a specified compd. on the surface of a carrier core of an inorg. material.
CONSTITUTION: A carrier contains a comp. of the formula in which X, Y, Z are each halogen, nitro, carboxy, carboxyalkylether, cyano, sulfo, or dialkylamino, and each of them may be same or different; l and n are each an integer of 0W3; and m is 0W2. The surface of carrier core particles are coated with a material contg. one of o-, m-, and p-terphenyl to prepare an effective coated carrier for developing an electrostatic charge image. Electron acceptance of the carrier is enhanced by attacking of the benzene rings of terphenyl to give excellent and stable charging characteristics of the resin and to obtain a toner superior in stability and high in durability. Said terphenyl is soluble in almost all the solvents generally used. Its content is 0.5W15wt%, preferably, 1W5wt% in the coating resin. When it is ≥15wt%, its effect exerted on charging is small, and when ≤0.5wt%, an amt. of charge is satd. and durability of the coating layer is adversely affected by addition of a high ratio of terphenyl to the resin.
TAMAKI KIYOSHI
TEZUKA TOSHIAKI
TAKAGIWA HIROYUKI
INABA NAOMI
