| 摘要 |
<p>PURPOSE: To provide a binary system developer that contains no electrostatic charge control agent being mainly attributable to a spent at time of copying, whose toner is able to improve its pulverizability for the developer as shearing force is concentrated on a relatively soft low molecular body interface in time of pulverizing, thereby making the occurrence of a charging failure is made so as to be checkable. CONSTITUTION: Toner grains contain fixing resin and magnetic powder dispersed in this resin, while this fixing resin consists of a composition containing both low and high molecular bodies with an anionic polar group each, and a content rate of this anionic polar group in the low molecular body is smaller than that of the anionic polar group of the high molecular body, and likewise an SP value of the low molecular body is smaller than that of the high molecular body. Carrier grains have a core grain and a covered layer which consists of a resin composition containing thermosetting resin and thermoplastic resin.</p> |
