| 摘要 |
PURPOSE:To eliminate variation in printing density due to influence of humidity of the environment by having electrified toner of the developing roller increased when the measured toner density by a reflective type density detection sensor is below a specified value. CONSTITUTION:A toner mark 10 is formed on a specified position on a photosensitive drum 1 by a process before the printing of a first letter is carried out, its density is measured by the reflective type density detection sensor 9, when the specified value is not reached by the measured value that information is informed to a control part of an electrophotographic method printer. In the control part, with one component toner method, the electrified toner quantity is increased to the specified value by further rotation of a developing roller 4. With two component toner method, the developer is further fed to the developing roller 4 and the quantity of the electrified toner is made sufficient. The printing action is started when the specified value is reached by the measured density value of the toner mark 10 of the sensor 9 by repeating this action. Thus, the variation in the printing density is controlled and the printing quality is improved. |
