| 摘要 |
PURPOSE:To prevent image troubles at the time when the volume of printed characters is small. CONSTITUTION:A printed character volume monitoring means 13 is provided in a concentration control means 1. Printed character data signals (signals by which printing information is converted into ON/OFF signals of a light source) 12 are given to the printed character volume monitoring means 13, and charge volume signals for controlling the rise and drop of high voltage are sent from the printed character volume monitoring means 13 to a charging transformer 9. The printed character volume monitoring means 13 counts the number of ON-signals of the printed character data signals 12 and compares, of for example, the number of ON-signals equivalent to the amount of four pages to a preset target value. When the number of ON-signals is below the target value, the charge volume signals are changed to raise the charged potential of a photoreceptor 6. Thus, the amount of movement of toner-volume in a developing machine 5 is increased, the printing density becomes thicker, and the consumption of the toner in the developing machine 5 is increased. |
