| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of providing stable images regardless of long-term image forming operation. <P>SOLUTION: In the image forming apparatus 100, the distance X from a photoreceptor 40 to a developing sleeve 41 is 100-650 μm, a toner has a weight average particle diameter Dm of ≤6.5 μm, an external additive includes inorganic fine particles having a primary particle diameter D of 30-700 nm in an amount Z of 0.1-2.5 pts.wt. based on 100 pts.wt. of the toner, and a developer index Y1 represented by following expression (1) satisfies following expression (2); (1) Y1=306X<SP>2</SP>-374X+154-(4.7Z<SP>2</SP>+4Z) (where the unit of X is [mm] and the unit of Z is [pts.wt.] based on 100 pts.wt. of toner base weight), (2) 40≤Y1≤120. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
