NEGATIVE CHARGE TYPE TONER FOR TWO-COMPONENT DEVELOPER

摘要

PROBLEM TO BE SOLVED: To obtain a negative charge type toner for a two-component developer which stabilizes an image in the early stage of use in which the mixing of a fresh toner for replenishment in a developer is started and has no environmental dependency and a long service life. SOLUTION: Negative charge type silica particles and titanium dioxide particles are stuck to the surfaces of toner particles not containing an electric charge controlling agent and consisting essentially of a colorant, a magnetic powder and a fixing resin containing anionic polar groups to obtain the objective toner for a two-component developer. The titanium dioxide particles have been treated with a lower alcohol and with an alkyltrialkoxysilane coupling agent when the toner is a toner for forming the developer and a toner for replenishment, respectively.