Image reader with focus and magnification detection control

摘要

There is disclosed an image reader in which the reading magnification can be changed optically to a value designated. The image reader provides a device for adjusting the reading magnitude by moving a lens in the direction of the optical axis thereof and adjusting the focusing by shifting the image sensor relative to the lens. Further, the image reader provides a device for measuring the magnification and calculates amounts of movements for the lens and image sensor respectively based upon the measured magnification and the designated magnification. The lens and image sensor are moved respectively by the amount calculated to give the designated magnification in the focused state.