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US 2004/0070796 A1Published application
Image scanner for use in image forming apparatus
AssigneeToshiba Tec Kabushiki Kaisha
InventorKazuo Sasama
Life of this patent
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Abstract
An image scanner of the present invention corrects a lens position when a lens moving signal for moving a lens is obtained by extracting a luminance signal from an image signal output from a CCD sensor and an object is dislocated from a focus position of the lens at an optional position.
Claims15
An image scanner comprising:
- a photoelectric conversion element which has a light-receiving face and outputs an electrical signal corresponding to the contrast of light emitted to the light-receiving face;
- an optical unit including a light source, a lens, and a plurality of mirrors which guide the light reflected from an object to which the light from the light source is emitted and thereby which is illuminated, the lens imaging the reflected light on the light-receiving face of the photoelectric conversion element;
- a photoelectric conversion element driving circuit which drives the photoelectric conversion element and fetches the electrical signal at a predetermined timing;
- a lens moving mechanism which moves the lens in an optical-axis direction by a predetermined distance;
- and
- a focus control circuit which generates a focus signal capable of setting an optimum position of the lens in accordance with the electrical signal output from the photoelectric conversion element and which outputs a lens moving signal showing a distance for the lens moving mechanism to move the lens in accordance with the focus signal.
3 more elements
An image scanner comprising:
- a CCD sensor which converts the image information on an object into an image signal;
- an illuminating unit which illuminates the object;
- a first mirror which guides image light which is the contrast of the light including the image information generated from the object illuminated by the illuminating unit in a predetermined direction;
- a second mirror which guides the image light transmitted from the first mirror in a predetermined direction;
- a third mirror which guides the image light transmitted by the second mirror in a predetermined direction;
- a lens which images the image light transmitted by the third mirror on the CCD sensor;
- a first mirror moving mechanism which movably holds the first mirror and the illuminating unit and is movable along the image information on the object;
- a second mirror moving mechanism which movably holds the second mirror and the third mirror and is movable by one half of a distance in which the first mirror moving mechanism is moved due to the movement of the first mirror moving mechanism;
- a driving unit for generating a thrust for moving the first and second mirror moving mechanisms in predetermined directions;
- a lens moving mechanism for moving the lens in the optical-axis direction predetermined distance by predetermined distance;
- a memory device capable of storing the electrical signal output from the CCD sensor in any one of the following forms:
- a) in the sequence corresponding to the arrangement of light-receiving elements of the CCD sensor and every region divided into several light-receiving elements,
- b) a plurality of electrical signals every same region about the sequence corresponding to the arrangement of light-receiving elements of the CCD sensor and a region unit divided every several light-receiving elements, and
- c) capable of holding a plurality of image data about scanning information on all scanning-object regions of the same object in the sequence corresponding to the arrangement of the light-receiving elements of the CCD sensor and including a region unit divided every several light-receiving elements;
- a focus control circuit which outputs a lens moving signal showing the distance for moving the lens moving mechanism every predetermined step and which outputs a selection signal for selecting the image data in the region of a step having the largest focus signal from the image data output from the CCD sensor and stored in the memory device at the position of the lens moved every step;
- and
- an output image memory including a control circuit which holds image data in which a focus is not dislocated every region unit and constructs output image data by successively outputting any image data of a) image data in the region units, b) a plurality of image data every same region in the region units, and c) a plurality of image data about the scanning information on all object regions of the same object in the region units.
14 more elements
Dependencies are inferred from the claim text.