Image reading apparatus

An image reading apparatus having a plurality of resolutions for reading an original image, for scanning the original image on a line basis to read the original image comprising:

• image pickup elements for photoelectrically converting optical information corresponding to darkness and brightness of the original image and outputting an analog image signal;
• a drive signal generation circuit which generates a plurality of drive signals for supplying a clock signal to respective photosensitive portions of said image pickup elements;
• a digital conversion circuit which converts the image signal into a digital signal by using the drive signals;
• a timing adjusting circuit which relatively changes and adjusts generation timings of the drive signals;
• and
• a non-volatile memory circuit which stores adjustment values of the generation timings of the drive signals given by said timing adjusting circuit, the adjustment value being a generation timing relative to a standard generation timing of the drive signal, wherein when the generation timings are adjusted, the adjustment values of the generation timings of the drive signals adjusted by said timing adjustment circuit are stored in said memory circuit;
• and
• wherein when the original image is to be read, said drive signal generation circuit is controlled to obtain the image signal, by referring to the adjustment values stored in said memory circuit.

A drive method for an image reading apparatus comprising:

• a timing adjusting step of an adjusting generation timing of a drive signal for driving at least an image pickup element which reads an object image and outputs an image signal of the object image;
• a storing step of storing an adjustment value of the generation timing of the drive signal adjusted in said timing adjusting step;
• and
• a drive signal generating step of generating the drive signal in accordance with the adjustment value stored in said memory step.