DEVELOPER FOR HEAT ROLL FIXING

摘要

PURPOSE:To obtain an image having a stable image density with good fixability and without ground fogging by consisting a titled developer of a magnetic carrier and magnetic toner essentially consisting of a specific styrene/acrylic copolymer and magnetic powder. CONSTITUTION:This developer for developing electrostatic charge images consists of the magnetic carrier and the magnetic toner essentially consisting of the styrene/acrylic copolymer having the weight average mol.wt. ranging 8X10<4>-14X10<4> and number average mol.wt. ranging 4X10<3>-9X10<3>. Offset is liable to arise and the shelf stability is deteriorated if the weight average mol.wt. and number average mol.wt. of the copolymer are below said values. The fixability is lower if said mol.wts. exceeds the above-mentioned values. The amt. of the magnetic powder to be incorporated into the toner is adequately in a 35-65wt% range. The magnetic force of the toner is too small and the toner is liable to be detached from a sleeve if the amt. is <35wt%. The resin component decreases and the toner is liable to be pulverized to increase the ruggedness on the toner surface if the amt. exceeds 65wt%.