| 摘要 |
PROBLEM TO BE SOLVED: To easily and automatically detect a fault in a laser beam and to make efficient troubleshooting as to a copying machine which is complex and multifunctional. SOLUTION: A sensor is calibrated (180) and the reflection factor RR100 of a 100% clean patch on a photoreceptor is recorded (182), special patches are arranged by only lasers A and B of double laser beams (188, 184) and the relative reflection factors RRA and RRB of those patches are recorded respectively (190, 186). When the lasers A and B are normal, they have nearly 50% halftone reflection factors. When RRA and RRB are larger than a given threshold value based upon RR100 (196, 192), it is decided that the lasers A and B are out of order (198, 194). When neither of the lasers A and B is out of order, it is considered that both beams are normal (200). |
