Image reading device and image forming apparatus comprising the same

摘要

An image reading device including an image sensor for optically reading a document and outputting an electric signal, a period control circuit for controlling the period of a horizontal synchronizing signal in order to change a time period during which charge is stored in the image sensor, and a scanning speed control circuit for controlling the scanning speed of the document to be a speed conforming to the period of the horizontal synchronizing signal. The horizontal synchronizing signal and the scanning speed are variably set to values corresponding to an image reading mode, for example.