| 摘要 |
<P>PROBLEM TO BE SOLVED: To prevent deterioration in a toner in a contact development process, to suppress the fusion of the toner onto a toner carrier, and further, to stably obtain an image of high quality having excellent half tone uniformity even under high temperature-high humidity for a long time. <P>SOLUTION: In a magnetic toner used for a contact development process where a magnetic toner is drawn near the surface of a developer carrier by a magnetic field generation means, the developer on the surface of the developer carrier is regulated by a developer regulation means, and the developer carrier is pressed, so as to be contacted with an image carrier, the magnetic toner comprises toner particles at least including a sulfonic acid based polymer, magnetic iron oxide and a binding resin. The sulfonic acid based polymer is a polymer or a copolymer having a sulfonic acid group, a sulfonate group or a sulfonic acid ester group. <P>COPYRIGHT: (C)2008,JPO&INPIT |
