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US 6,892,945 B2Granted
Structure for preventing extraneous light from entering image reading apparatus
AssigneeCanon Kabushiki Kaisha
InventorKazuo Shishido
Life of this patent
Estimating the term…
Abstract
An image reading apparatus for reading a document has an image sensor unit, which is moved along a platen glass in a sub-scanning direction, mounting an LED, a light guide and a sensor. A white reference panel for use of shading correction is provided on the platen glass on the side thereof opposite the image sensor unit. Light shield plates are provided on the platen glass on the side facing the image sensor unit along both sides of the white reference panel.
Claims23
An image reading apparatus comprising:
- an illumination unit adapted to illuminate a subject;
- an image reading unit having a line sensor adapted to read an image of the subject illuminated by said illumination unit;
- a transparent member having a light transmitting property provided between the subject and said image reading unit;
- a reference member, which is provided on said transparent member and extends in a main scanning direction of said line sensor, on a side that the subject is to be placed, adapted for use as an illuminance reference for shading correction applied to an image signal that is output from said image reading unit;
- and
- a light shielding member provided along said reference member in contact with said transparent member on the other side of the transparent member that said reference member is provided, so as to prevent light, which enters from outside through said transparent member, from being incident on said reference member when the line sensor reads said reference member.
3 more elements
An image reading apparatus comprising:
- an illumination unit adapted to illuminate a subject;
- an image reading unit adapted to read an image of the subject illuminated by said illumination unit;
- a transparent member having a light transmitting property provided between the subject and said image reading unit;
- a reference member, which is provided on said transparent member, adapted for use as an illuminance reference in order to correct an image signal that is output from said image reading unit;
- a case adapted to mount said illuminating unit and said image reading unit and move in a sub-scanning direction alone said transparent member;
- and
- a light shielding member provided on a frame of said case along a main scanning direction, wherein said light shielding member is in contact with said transparent member so as to prevent light, which enters from outside through said transparent member, from being incident on said reference member.
4 more elements
An image reading apparatus comprising:
- an illumination unit adapted to illuminate a subject;
- an image reading unit having a line sensor adapted to read an image of the subject illuminated by said illumination unit;
- a transparent member having a light transmitting property provided between the subject and said image reading unit;
- a reference member, which is provided on said transparent member and extends in a main scanning direction of said line sensor, adapted for use as an illuminance reference for shading correction applied to an image signal that is output from said image reading unit;
- and
- a light shielding member provided along said reference member on a side of said image reading unit with respect to said transparent member,
- wherein said light shielding member is in contact with said transparent member and extends from said transparent member for a length capable of covering at least a part of a space between the surface of said transparent member and said image reading unit when said image reading unit is below said reference member.
4 more elements
Dependencies are inferred from the claim text.