| 摘要 |
PURPOSE:To form a picture with high quality by selecting a pulse width modulation circuit and an intensity modulation circuit depending on the property of a picture signal and radiating a beam. CONSTITUTION:In the image forming device in which a beam modulated by a picture signal D inputted externally irradiates a receptor to form a picture having gradation, when the picture signal D formed from the picture having dot structure such as a print original is inputted, a selection circuit 10 selects an intensity modulation circuit 9. Moreover, when the picture signal D comprising an original such as a photograph or a picture is inputted, a pulse width modulation circuit 8 is selected. Through the constitution above, when the modulation is implemented by the intensity modulation system and the picture is generated, no moire is caused and the picture with excellent picture quality is obtained, and when the picture is generated by the pulse width modulation system, a stripe due to uneven speed of a photosensitive drum 5 is not caused and the picture with high quality is obtained. |
