| 摘要 |
PURPOSE:To adjust printing density properly in response to the kind of a picture automatically by discriminating the kind of the picture to be printed and fluctuating development bias voltage on the basis of the result of the discrimination. CONSTITUTION:When a printing data is input from a host controller 30, a CPU 21 decides whether a picture to be printed is written by a character or not on the basis of the printing data, and electrophotographic process treatment is started by an image forming section 15 as it is when the picture to be printed is written by the character. When the picture is not written by the character, control signals S1, S2 are output to a laser beam source 16 and a development bias power supply 18, the quantity of output light is increased slightly, development bias voltage VB is controlled so as to be to some extent lowered, and electrophotographic process treatment is started by the image forming section 15. Accordingly, printing density is adjusted automatically in response to the kind of the picture, thus acquiring the distinct printing picture at all times. |
