| 摘要 |
PROBLEM TO BE SOLVED: To provide an electrophotographic developer capable of retaining stable charging property over a prolonged period of time, and a method for evaluating the developer. SOLUTION: The developer comprises a toner and a carrier surface-coated with a coating material containing a fluorocarbon resin, an intensity Ta of fluorine obtained by measuring the toner in the initial developer by fluorescent X-ray analysis and an intensity Tb of fluorine obtained by measuring toner in the developer, after printing 3,000 sheets in a printing ratio of 5% by fluorescent X-ray analysis satisfy the relational expression (I): (Tb/Ta)<2.0, and the intensity Ca of fluorine obtained by measuring the carrier in the initial developer by fluorescent X-ray analysis and the intensity Cb of fluorine obtained by measuring carrier in the developer, after printing 3,000 sheets in a printing ratio of 5% by fluorescent X-ray analysis satisfy the relational expression (II): 0.90<(Cb/Ca)<0.98. COPYRIGHT: (C)2006,JPO&NCIPI |
