ELECTROPHOTOGRAPHIC TONER AND CONTACT DEVELOPING METHOD USING THE TONER

摘要

PROBLEM TO BE SOLVED: To ensure high durability and stable positive chargeability by incorporating polyester resin having specified acid and hydroxyl values, an electric charge controlling resin into which functional groups imparting positive charges to a toner have been introduced by a specified amt. and a specified amt. of fine TiO2 particles. SOLUTION: This toner contains polyester resin having <=10mgKOH/g acid value and <=40mgKOH/g hydroxyl value as a fixing resin, an electric charge controlling resin into which functional groups imparting positive charges to a toner have been introduced by 2-5mol% and 0.1-2 pts.wt. TiO2 based on 100 pts.wt. of the polyester resin as a surface treating agent for a toner. Since the acid value of the polyester resin is low, positive charging can be efficiently attained by the action of the electric charge controlling resin. Since the hydroxyl value is also low, satisfactory moisture resistance is ensured.