ELECTROSTATIC CHARGE IMAGE DEVELOPER

摘要

PROBLEM TO BE SOLVED: To obtain excellent developing property and safeness for long-term printing and to decrease production of fog by incorporating a positive electrification toner comprising a specified positive charge controlling agent and a negative charge controlling resin. SOLUTION: This developer contains a positive electrification toner described below. The toner contains a charge controlling material comprising a positive charge controlling agent and a negative charge controlling resin. The total amt. of the positive charge controlling agent and the negative charge controlling resin is 2 to 10 pts.wt. to 100 pts.wt. of the binder resin. The weight ratio of the positive charge controlling agent to the negative charge controlling resin is 100:1 to 3:1. The product of the acid value (KOH mg/g) of the negative charge controlling resin and its content to 100 pts.wt. of the binder resin is 1 to 50. The positive charge controlling agent is preferably used as a master batch with a resin having solubility with the binder resin of the toner, preferably with the binder resin of the toner. As for the negative charge controlling resin, any material can be used as far as it can uniformly produce negative charges on the toner surface and does not cause spent of a charge imparting material.