| 摘要 |
PROBLEM TO BE SOLVED: To provide an electrophotographic printer capable of detecting printing density all over the printing paper and performing printing with uniform density. SOLUTION: Toner marks 3 to 6 are printed in the four corners of each page of a printing paper 7. A left-side toner density sensor 1 and a right-side toner density sensor 2 are installed at positions corresponding to side parts on both sides of the printing paper. A toner density control part 8 compares respective voltage values obtained by converting the printing density of the toner marks 3 to 6 with a reference voltage range value and outputs a toner supply command to a toner supply motor 9 when any of the printing density of the toner marks 3, 4, 5 and 6 is below the lower limit value of a reference range value, and outputs a toner supply stop command to the motor 9 when any of the printing density of the toner marks 3, 4, 5 and 6 exceeds the upper limit value of the reference range value. |
