Abstract: A self-diagnostic system for image reading equipment having an imaging unit and at least one circuit board, including a pattern generator, which generates a prescribed pattern signal, disposed at the input end and/or the output end of the circuit board. According to this system, a source of problems occurring in the image reading equipment can be identified, that is, a faulty component can be identified by performing a copying operation for a pattern generated by the pattern generator.

Abstract: An image data control system for use in an image reading equipment, in which analog signals output from a line sensor, which represent the amounts of light reflected from an original sheet are converted into digital signals by analog/digital conversion, and then the digital signals are converted into density signals to obtain original sheet reading signals in the form of the density signals, the system characterized in that offset control are performed by an offset control circuit and dark time output adjustment by the unit of picture elements are performed by a dark time correction circuit, respectively, after performing gain control by a gain control circuit.

Abstract: An image sensor is operable in a read state, a rest state, and a stand-by state. Control signal generating means generate a control signal. The control signal has a first constant preset level during the read state, a second preset level during the rest state, and alternates between the first and second levels at a duty ratio during the stand-by state. Drive circuit means transfer current to the image sensor in response to the control signal. Therefore, current is continuously transferred to the image sensor during the read state, no current is transferred during the rest state, and current is intermittently transferred to the image sensor at the duty ratio during the stand-by state.