| 摘要 |
PROBLEM TO BE SOLVED: To provide an image forming device capable of preventing an abnormal image and a machine failure caused by a minute amount offset. SOLUTION: Reflection density (Vsg) on a photoreceptor drum is beforehand read by a reflection density sensor (S52). Copy processing is performed (S53), when operation equivalent to the specified number of sheets for copy is finished (S54), the reflection density (Vsgp) on the photoreceptor drum is read again by the reflection density sensor 41 (S55) at a place where a developing motor is driven. The factor (a) of a surface staining level is succeedingly decided, based on the Vsgp/Vsg. For example, 9/10 is defined as a threshold, (a) equals 1 when the Vsgp/Vsg is larger than the threshold and (a) equals 2 when the Vsgp/Vsg is equal to or less than the threshold (S56). In a system in which a staining change is large, a value obtained by multiplying (a) by the number (n) of sheets for the copy is integrated (S57) and the service life of a fixing roller 23 is a place where the value N exceeds a specified value C. When N exceeds C, the display of 'roller exchange' is performed (S59). |
