Image reading device

An image scanning device for scanning an image on an original document placed on a document table, by using light irradiation means scanned along the document table, the image scanning device comprising:

• a stepping motor for moving the light irradiation means with use of either one of first and second phase exciters of different excitation modes;
• reception means for receiving a scanning magnification for the image of the original document, supplied from an external device;
• identifying means for identifying an end portion of the original document, which faces a light irradiation start position on the document table, by detecting a size of the original document placed on the document table;
• first movement means for controlling the stepping motor to move the light irradiation means as accelerating it to a moving speed based on a minimum scanning magnification for the image of the original document, from an initial position located outside a document scanning region of the document table to a first predetermined position, by excitation of the first phase exciter;
• second movement means for controlling the stepping motor to move the light irradiation means at the moving speed based on the minimum scanning magnification for the image of the original document, from the first predetermined position to a second predetermined position located outside the document scanning region of the document table by excitation of the first phase exciter;
• third movement means for controlling the stepping motor to move the light irradiation means as decelerating it to the moving speed based on the scanning magnification, if the received scanning magnification is that other than the minimum scanning magnification for the image of the original document, or as maintaining the moving speed based on the scanning magnification if the received scanning magnification is the minimum scanning magnification, from the second predetermined position to a third predetermined position located outside a document scanning region of the document table, which varies its position depending on the scanning magnification of the image of the original document, by excitation of the first phase exciter;
• fourth movement means for controlling the stepping motor to move the light irradiation means at the moving speed based on the scanning magnification, from the third predetermined position to a light irradiation start position of the document table and from the light irradiation start position of the document table to an end portion of the original document on the document table by excitation of the second phase exciter;
• and
• photoelectric conversion means for converting an amount of reflection light while irradiating the original document on the document table by the light irradiating means moved by the fourth moving means, into an electric signal.

An image scanning device for scanning an image on an original document placed on a document table, by using light irradiation means scanned along the document table, the image scanning device comprising:

• a stepping motor for moving the light irradiation means with use of either one of first and second phase exciters of different excitation modes;
• reception means for receiving a scanning magnification for the image of the original document, supplied from an external device;
• first movement means for controlling the stepping motor to move the light irradiation means as accelerating it to a moving speed based on a minimum scanning magnification for the image of the original document, from an initial position located outside a document scanning region of the document table to a first predetermined position, by excitation of the first phase exciter;
• second movement means for controlling the stepping motor to move the light irradiation means at the moving speed based on the minimum scanning magnification for the image of the original document, from the first predetermined position to a second predetermined position located outside the document scanning region of the document table by excitation of the first phase exciter;
• third movement means for controlling the stepping motor to move the light irradiation means as decelerating it to the moving speed based on the scanning magnification, if the scanning magnification is that other than the minimum scanning magnification for the image of the original document, or as maintaining the moving speed based on the scanning magnification when the scanning magnification is the minimum scanning magnification, from the second predetermined position to a third predetermined position located outside a document scanning region of the document table, which varies its position depending on the scanning magnification of the image of the original document, by excitation of the first phase exciter;
• fourth movement means for controlling the stepping motor to move the light irradiation means at the moving speed based on the scanning magnification, from the third predetermined position to a light irradiation start position of the document table by excitation of the second phase exciter;
• fifth movement means for controlling the stepping motor to move the light irradiation means at the moving speed based on the scanning magnification, from the light irradiation start position on the document table to an end portion of the original document on the document table by excitation of the second phase exciter;
• and
• photoelectric conversion means for converting an amount of reflection light while irradiating the original document on the document table by the light irradiating means moved by the fifth moving means, into an electric signal.