| 摘要 |
PURPOSE: To always precisely calibrate a density sensor and to obtain a high- quality image by an excellent density control action by calibrating the density sensor by using a light source set on the outside of of the sensor. CONSTITUTION: A forming means forming a toner image for controlling density on a photoreceptor drum 1 is constituted of a laser driver 7 so that the density of the toner image is detected by the density sensor 14. When timing that the sensor 14 is required to be calibrated is detected, the processing of a density sensor calibration mode is executed by a CPU 15. In such a case, different image signals are respectively transmitted to the laser driver 7 in a fixed time by the CPU 15, and a laser diode 8 is made to emit light by the different light quantity thereof and the measurement surface 14a of the sensor 14 is irradiated with the light through an optical path 13. Next, a value outputted from the sensor 14 receiving the light in timing that the diode 8 emits the light of each quantity is fetched in a RAM 17 by the CPU 15. |
