Image reading apparatus

Abstract

An image reading apparatus includes: a light source; an image capturing device, opposed to the light source through a document table adapted to support a document and operable to receive light emitted from the light source; a detector, operable to detect a light-reception state of the image capturing device when an instruction for reading the document is given; and a corrector, operable to correct a relative position in a sub scanning direction between the light source and the image capturing device based on a detection result of the detector.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described with reference to the accompanying drawings, wherein like numbers reference like elements.

FIG. 1 is a perspective view illustrating an appearance of a scanner according to a first embodiment of the invention.

FIG. 2 is a longitudinal-section front view of the scanner.

FIG. 3 is an exploded perspective view illustrating a transmissive light source.

FIG. 4 is a diagram illustrating a relative position between a transmissive light source and an image capturing device (first).

FIG. 5 is a diagram illustrating a relative position between the transmissive light source and the image capturing device (second).

FIG. 6 is a diagram illustrating a relative position between the transmissive light source and the image capturing device (third).

FIG. 7 is a graph illustrating a light intensity distribution of the transmissive light source in a sub scanning direction.

FIG. 8 is a flowchart illustrating a process performed by the scanner (first).

FIG. 9 is a diagram illustrating an emission shape of a transmissive light source according to a second embodiment of the invention.

FIG. 10 is a diagram illustrating a relative position between a transmissive light source and an image capturing device (first).

FIG. 11 is a flowchart illustrating a process performed by the scanner (second).

FIG. 12 is a diagram illustrating an emission shape of a transmissive light source according to a third embodiment of the invention.

FIG. 13 is a diagram illustrating a relative position between the transmissive light source and the image capturing device (second).

FIG. 14 is a flowchart illustrating a process performed by the scanner (third).

FIG. 15 is a diagram illustrating an emission shape of a transmissive light source according to a fourth embodiment of the invention.

FIG. 16 is a diagram illustrating a relative position between the transmissive light source and the image capturing device (third).

FIG. 17 is a flowchart illustrating a process performed by the scanner (fourth).

Claims

1. An image reading apparatus comprising: a light source;an image capturing device, opposed to the light source through a document table adapted to support a document and operable to receive light emitted from the light source;a detector, operable to detect a light-reception state of the image capturing device when an instruction for reading the document is given; anda corrector, operable to correct a relative position in a sub scanning direction between the light source and the image capturing device based on a detection result of the detector.

2. The image reading apparatus according to claim 1, wherein the detector detects a light intensity received by the image pickup device.

3. The image reading apparatus according to claim 2, wherein the corrector corrects the relative position in the sub scanning direction between the light source and the image capturing device, when the light intensity is less than a predetermined value.

4. The image reading apparatus according to claim 3, wherein the predetermined value is set based on a light intensity distribution in the sub scanning direction of the light emitted from the light source.

5. The image reading apparatus according to claim 1, wherein the light source emits light having an emission width varying in a main scanning direction depending on a position thereof in the sub scanning direction, andthe detector detects a light-receiving width of the image capturing device.

6. The image reading apparatus according to claim 5, wherein the corrector corrects the relative position in the sub scanning direction between the light source and the image capturing device, when the light-receiving width deviates from a predetermined range.

7. The image reading apparatus according to claim 1, further comprising: a reference light source, operable to emit light which can be received by the image capturing device in accordance with a relative position between the light source and the image capturing device, whereinthe detector detects a light-receiving pattern of the image capturing device.

8. The image reading apparatus according to claim 7, wherein the corrector corrects the relative position in the sub scanning direction between the light source and the image capturing device in accordance with the light-receiving pattern.