| 摘要 |
PURPOSE:To obtain a picture having no fluctuation by inputting an optical sensor output and reference voltage which is set in advance in accordance with each face of a rotary polyhedral mirror, switched at every face and outputted to a converter, generating a pulse when both coincide with each other, and using the pulse concerned as a horizontal synchronizing signal of scanning. CONSTITUTION:When a mirror rotates and executes scanning, a luminous flux crosses an optical sensor immediately after scanning of each mirror face is started, and a pulse output appears in an amplifier. An output of the amplifier is not constant due to a difference of intensity of the luminous flux which is made incident to each mirror face. A comparator compares the reference voltage supplied through an analog switch from a reference voltage generating part with the amplified output of the optical sensor and generates a pulse when both of them become the same potential. In accordance with an inclination of a rise of the amplified output of the optical sensor, the reference voltage of the comparator is varied, therefore, the output timing of the comparator is matched exactly, it is used as a synchronizing signal and a picture signal of a fixed length is inputted in a constant interval of time after the pulse is generated, by which a picture having no fluctuation in the horizontal direction can be obtained. |
