Electrophotographic toner comprising an external additive and image forming apparatus containing the electrophotographic toner

摘要

An external additive for a toner, which has an average particle diameter not greater than 100 nm and includes an inorganic particulate material; and a hydrophobizing agent which is present on the inorganic particulate material in an amount of Ws by weight and present as a free hydrophobizing agent in an amount of Wf by weight, wherein a residual ratio defined as a ratio äWs/(Ws+Wf)üx100 is from 40 to 98.5 %, and wherein at least one of a compound having an organopolysiloxane structure and a compound having a ring siloxane structure is detected when the external additive is analyzed by a pyrolysis gas chromatography mass spectroscopy method after the external additive is washed with chloroform.