| 摘要 |
PROBLEM TO BE SOLVED: To more accurately judge the life of an electrostatic latent image carrier after its use in an image forming device. SOLUTION: In the image forming device provided with a latent image forming means for forming an electrostatic latent image corresponding to an image information signal on an electrostatic latent image carrier 1 and a developing means 4 for turning the electrostatic latent image into a developed image with a developer 5, reference patch images of high and low densities are formed to measure the toner concentrations of these two images, two of the comparatively high and low concentration reference signals of plural image information reference signals for controlling the concn. are set and two of these two measured concentration signals and a reference signal are compared. When the measured concentration signals are not in the fixed range of the reference signal, toner is supplied and a primary current and a laser exposure are controlled, so that the remeasurement of the concn. and comparison with the reference signal are attained. When the measured concentration signals are not in the range of the reference signal, it is judged that the electrostatic latent image carrier 1 is used to the limit. |
