| 摘要 |
PROBLEM TO BE SOLVED: To provide an image forming device which is hardly affected by environmental change and the change with the lapse of time and excellent in half tone reproducibility. SOLUTION: In the image forming device provided with an image carrier 1, electrostatic latent image forming means (20 and 30) and a developing means 3, the developing means 3 has a saturation characteristic in a region where a curve in developing toner weight with respect to a contrast potential set by a developing bias potential Vb and the entire exposure part potential Vi of the image carrier is at a fixed contrast potential or more. An inclination of the curve in the developing toner weight with respect to the contrast potential is set to satisfy the relation of|Vs(15)|×1.1<|Vb-Vi|, when the contrast potential at a relative humidity of 15% at the 1/5 point of an inclination when the contrast potential is in the vicinity of zero is defined as Vs (15). |
