| 摘要 |
PURPOSE:To obtain stable line width in printing extending over a long time by changing the spot diameter of a laser beam on a photosensitive body according to a time that developer is stirred and mixed in a developing device. CONSTITUTION:When a parallel plate glass 12 is inserted between a first cylindrical lens 14 and a scanner 15, laser light 21' traces an optical path shown by a dotted line and the diameter of the spot on the photosensitive body 18 becomes thick. Then, since the state of the secular change of the developer becomes different by the developer itself and the constitution of the developing device, relation between the state of the secular change and the line width is previously stored and the diameter of the spot is changed. Thus, the stable line width with aging stability is obtained extending over a long period and the life of the developer is prolonged. |
