Image reading system
AssigneeCanon Kabushiki Kaisha
InventorNaohisa Suzuki
Life of this patent
Estimating the term…
Abstract
A scanner unit moves in the scanning direction to read an original image, and thereafter, returns to the home position. In this case, the accumulation time of a line CCD is selected to set the resolution, and a control processing unit controls the product of the LED current in the optical system and the accumulation time to always become constant, thereby stabilizing heat accumulation of the LED. During movement in the return direction, the LED current is set to be lower than that upon reading, and the average current in the two directions is controlled to become constant irrespective of the accumulation time.
Claims88
An image reading system comprising:
- (a) photoelectric conversion means for converting light from an original into an image signal;
- (b) a light source for illuminating the original;
- and
- (c) control means for changing each of an accumulation time of a charge in said photoelectric conversion means and a current to be supplied to said light source while maintaining a product thereof to be a constant.
A control apparatus for an image reading apparatus, which has photoelectric conversion means for converting light from an original into an image signal, and a light source for illuminating the original, comprising control means for changing each of an accumulation time of a charge in said photoelectric conversion means and a current to be supplied to said light source while maintaining a product thereof to be a constant.
An image reading system comprising:
- (a) photoelectric conversion means for converting light from an original into an image signal;
- (b) a light source for illuminating the original;
- (c) scanning means for reciprocally scanning said photoelectric conversion means in forward and backward movements relative to the original;
- and
- (d) control means for controlling an average current supplied to said light source in the forward and backward movements to be constant.
A control apparatus for an image reading apparatus, which includes photoelectric conversion means for converting light from an original into an image signal, a light source for illuminating the original, and scanning means for reciprocally scanning said photoelectric conversion means in forward and backward movements relative to the original, comprising control means for controlling an average current supplied to said light source in the forward and backward movements to become constant.
Dependencies are inferred from the claim text.