| 摘要 |
<p>PURPOSE:To provide the carrier excellent in durability, low in secular change of an electrostatic material and a resistance characteristic and capable of maintaining the picture quality of an initial stage even at long period use by using the magnetic having a specified resistance as a core material and coating the magnetic with resin. CONSTITUTION:This carrier is composed of the magnetite being the core material having >=10<7>OMEGA.cm resistance fundamentally and 10<7>-10<14>OMEGA.cm resistance at the time of impressing of 100V voltage preferably and the resin coating the surface of the core material. The production method of a high resistant magnetite is exemplified by the chemical treatment or mechanical treatment of a general magnetite or the treatment using jointly these method, etc. When the carrier is used as a two-component system developer, the change of resistance is hardly caused even at long period repeating use. And, the picture quality of an initial stage is maintained and high quality picture is formed on a copying paper after continuous use even in the valuation of a picture quality.</p> |
