| 摘要 |
PURPOSE:To take a copy of desired color without replacing a developing machine by installing 2-3 developing machines which supply toner of optional color and scatter toner sticking on a surface over the surface of a photosensitive drum during development at development positions. CONSTITUTION:Developing machines 21-23 each consists of a housing 25 with a toner supply port 24, a couple of developing rolls 26 which are installed rotatably in the housing 25 and have 10<2>-10<8>OMEGA-cm specific surface resistance, and a metallic blade 27 which foms one-two toner film layers on the surfaces of the developing rolls 26. For example, red toner, green toner, and blue toner are loaded in the developing machines 21-23 and when a bias voltage VB is impressed to each roll 26 on every turn of the drum 6, toner of each color is scattered toward the photosensitive drum 6 and sticks on a latent image. In this case, the number of rotation of the developing rolls 26 are controlled to make a density adjustment, so three developing machines are used in combination to take a copy of any color. |
