| 摘要 |
PURPOSE:To keep the characteristic of recording density constant by forming a reference toner pattern on one end of a photosensitive drum and reading it with one optical sensor. CONSTITUTION:The optical sensor 161 is constituted of a light emitting element and a light receiving element provided with an optical filter on its light receiving surface. By irradiating the reference toner pattern RP formed on the photosensitive drum 18c with light and receiving the reflected light, the reflectance of light, that means, the density, of the reference toner pattern RP is detected. A signal for energizing laser light is corrected according to the detected density so as to prevent the occurrence of the unevenness of density. Now, the optical sensors for detecting the density of the reference toner pattern RP formed on each photosensitive drum are provided on the recording systems of M, Y and BK colors as well as the recording system of cyanogen. The signal for writing an electrostatic latent image is corrected in order to make the detected density approach target density. Thus, the characteristic of recording density of the entire device can be kept constant. |
