Abstract: An image scanner apparatus is composed of a housing, an optical unit positioned in the housing, a drive mechanism driving the optical unit. The drive mechanism includes first and second wires connected to the optical unit, and a drive motor driving the first and second wires. One end of the first wire is connected to a first fixture, and one end of the second wire is connected to a second fixture. The first fixture is secured to a first wire-retaining member positioned outside the housing at a first securing position, and the first wire-retaining member retains the first fixture so that the first securing position is adjustable.

Abstract: An image reading apparatus comprises a correction coefficient determining circuit 4 for determining a correction coefficient per each bit of white reference data in a main scanning direction which are read immediately before reading an original image, a correction coefficient modifying circuit 5 for producing a modified correction coefficient, and a correction coefficient predicting circuit 6 for producing a predicted correction coefficient with reference to the modified correction coefficient. If an absolute value of a difference between the correction coefficient and the predicted correction coefficient is smaller than and not smaller than a predetermined threshold value, the correction coefficient modifying circuit 5 produces the correction coefficient and the predicted correction coefficient as the modified correction coefficient respectively. A correction coefficient memorizing circuit 7 memorizes the modified correction coefficient as shading correction coefficient data.

Abstract: An image scanner apparatus is composed of a housing, an optical unit positioned in the housing, a drive mechanism driving the optical unit. The drive mechanism includes first and second wires connected to the optical unit, and a drive motor driving the first and second wires. One end of the first wire is connected to a first fixture, and one end of the second wire is connected to a second fixture. The first fixture is secured to a first wire-retaining member positioned outside the housing at a first securing position, and the first wire-retaining member retains the first fixture so that the first securing position is adjustable.

Abstract: An image reading apparatus comprises a correction coefficient determining circuit 4 for determining a correction coefficient per each bit of white reference data in a main scanning direction which are read immediately before reading an original image, a correction coefficient modifying circuit 5 for producing a modified correction coefficient, and a correction coefficient predicting circuit 6 for producing a predicted correction coefficient with reference to the modified correction coefficient. If an absolute value of a difference between the correction coefficient and the predicted correction coefficient is smaller than and not smaller than a predetermined threshold value, the correction coefficient modifying circuit 5 produces the correction coefficient and the predicted correction coefficient as the modified correction coefficient respectively. A correction coefficient memorizing circuit 7 memorizes the modified correction coefficient as shading correction coefficient data.

Abstract: An image scanning unit for correcting a variation in magnification caused by an inclination of optical visual-line between a manuscript and a photoelectric conversion element when a full-speed scan reciprocating bed and a half-speed scan reciprocating bed are scanned in the sub-scan direction. The image scanning unit has: an optical system that leads light reflected on the manuscript to the photoelectric conversion element; a marking that is disposed on the optical visual-line of the full-speed scan reciprocating bed; a light source that supplies light to the marking; and a control circuit for accumulating marking information that is input through the optical system to the photoelectric conversion element and detecting an inclination of optical visual-line by comparing the accumulated marking information and regular marking information at regular optical visual-line, and for canceling the variation in magnification in the sub-scan direction caused by the detected inclination of optical visual-line.