| 摘要 |
PROBLEM TO BE SOLVED: To control the energy level by a simple method with high accuracy by providing first and second modes in an exposure means and obtaining an inflection point based on each variation of the potentials by electrification of test electrostatic latent images detected in the second mode, so as to control the energy level of exposure in the first mode. SOLUTION: The exposure means 7 has the second mode for forming plural test electrostatic latent image on a drum 1 with exposed light at a different energy level, besides the first mode of a normal operation mode for forming an electrostatic latent image. In the second mode, the test electrostatic latent images are formed on the drum 1 with the exposed light at the different energy level by the exposure means 7. A potential sensor 8 is arranged in proximity to the drum 1, between the exposure means 7 and a developing means 30. An arithmetic part 82 obtains the inflection point of the drum 1 by a calculation, based on each variation of the potentials by electrification of the test electrostatic latent images, with a signal from the sensor 8. A control means 84 controls the current value of a scanning part, to control the energy level of the exposed light for the drum 1. |
