| 摘要 |
PURPOSE:To prevent recording of a picture to a recording unnecessary part by interrupting forcibly a picture signal to be supplied to the outside of an effective picture recording range by means of a signal from an effective picture recording range detecting means. CONSTITUTION:A picture signal generated in a recording information generating section 1 is fed to a semiconductor laser 20 in a recorder 3 and the picture signal modulates a laser beam. After the moludation beam is polarized by a scanner 21, the beam is exposed to a phtosensitive body on a photosensitive drum 10 via a lens 22. The position of the laser beam is detected by a beam detector 23, the detection signal is transmitted to the generating section 1 to synchronize a latent image on the drum 10 with the picture signal. A device 3 counts the number of clocks until a picture write start point CTB and a write end point CTC in the main scanning direction A, and when the detection pulse of the detector 23 does not reach the CTB and exceeds the CTC, the picture signal from the generation section 1 is interrupted. The picture signal is controlled as to the sub-scanning direction B by discriminating paper size by the signal of a switch 39 or detecting paper size by means of paper size detectors 40a, 40b. |
