| 摘要 |
PURPOSE:To form a reference halftone toner image with constant density by using an opening part formed on a main body as a reference pattern for toner density detection and using a scorotron charger as an electrifying charger. CONSTITUTION:Light projected on the opening part 18a by an exposure lamp 11 is transmitted out of a copying machine by the opening part 18a, so charges on the surface of a photosensitive drum 1 corresponding to it are not erased and a reference latent image of the reference pattern (opening part 18a) is formed. Further, the opening part 18a as the reference pattern forms a constant reference latent image at each time without varying in the quantity of reflected light owing to the sticking of powdery toner. This constitution uses the scorotron charger 2 as the electrifying charger and a no-image area is charged electrostatically to a potential lower than an image area, so a halftone latent image is formed and the toner concentration of, specially, a color developing device is accurately measured and controlled. |
