| 摘要 |
PURPOSE:To measure a base reflecting light quantity and a test toner image reflecting light quantity at a place where the surface of an electrostatic latent image carrier is in an almost constant state and to eliminate the variance of a measured value by synchronizing base reflecting light quantity measuring timing and test toner image reflecting light quantity measuring timing with the rotational period of the electrostatic latent image carrier. CONSTITUTION:The density of the surface of a photosensitive body 1, and the toner sticking quantity of a test toner image formed on the surface are optically measured by a reflection type photosensor 15 composed of an LED 16 and a photodiode 17. Respective intervals T1 and T2 of the base reflecting light quantity measuring timing (t1), saturation level test toner image reflecting light quantity measuring timing (t2), and half-tone test toner image reflecting light quantity measuring timing (t3), and the rotational period of the photosensitive drum 1, are synchronized. Thus, a reflecting light quantity from the test toner image is measured at the same position as a base reflecting light quantity measuring position, and the error in the operation of a developing bias voltage is cancelled. |
