| 摘要 |
PURPOSE:To obtain an image which is free from any distortion at the center and edge parts of scanning and at a low price, by revoluting or vibrating a light source itself and at the same time controlling the writing period of data in response to the deflecting angle of the optical beam. CONSTITUTION:A motor control part 61 applies the driving signal to a revolution driving means to perform the forward and backward revolutions alternately. As a result, a light source 1 itself is deflected alternately with + or -theta defelecting angle, and the optical beam of the source 1 scans horizontally the surface of a photosensitive drum 5. Here a clock synchronization compensating circuit 10 controls the period of the clock signal given from a clock oscillator 9 so as to satisfy the following relation. That is, the data reading period T corresponding to a dot given from a buffer memory 7 is longest with theta=0 and is short with theta=+ or -max (when a light spot is across the projection face). As a result, the length per dot on the scanning line can always be set constant regardless of the deflecting angle theta of the optical beam. |
