Image Reading Apparatus

• US 20060245013A1
• Filed: 04/28/2006
• Published: 11/02/2006
• Est. Priority Date: 04/28/2005
• Status: Active Grant

• Current Assignee: Brother Kogyo Kabushiki Kaisha (Brother Industries Limited)
• Original Assignee: Brother Kogyo Kabushiki Kaisha (Brother Industries Limited)
• Inventors: Kato, Tetsuya, Ikeno, Takahiro, Osakabe, Yoshinori
• Granted Patent: US 7,952,770 B2
• Time in Patent Office: Days
• US Class Current: 358/487
• CPC Class Codes: H04N 1/00814 according to a detected condition or state of the reading apparatus, e.g. temperature
• CPC Class Codes: H04N 1/00835 Detecting external or ambient light
• CPC Class Codes: H04N 1/1017 the main-scanning components remaining positionally invariant with respect to one another in the sub-scanning direction

Abstract

An image reading apparatus includes: a reading table having a transparent plate having an exposed area which constitutes a part of an outer surface of the table exposed to the exterior, and on which a document with an image thereon is placed; a document holding member movable relative to the table and between a closed and an open position, and thus holding the document and covering the plate; a scanning device disposed on a side of the plate opposite to the side on which the document is placed on the plate, the scanning device being reciprocated in a direction along the plate; an image reading device mounted in the scanning device and including a light source, the reading device emitting light from the light source toward the document on the plate, and receiving the reflected light from the document, to read the image thereby; a control unit controlling reading by the reading device, and a reciprocating movement of the scanning device; a reference member disposed within the exposed area, and used as a reference when an amount of the light emitted from the light source is adjusted; and an external-light detector determining whether external light is entering the table, based on at least one value obtained as a result of reading the reference member.

Claims

1. An image reading apparatus comprising:

a reading table having a transparent plate having an exposed area which constitutes a part of an outer surface of the reading table exposed to the exterior, and on which a document with an image thereon is placed;

a document holding member movable relative to the reading table and between a closed position and an open position, and thus holding the document and covering the transparent plate;

a scanning device which is disposed on a side of the transparent plate opposite to the side on which the document is placed on the transparent plate, the scanning device being reciprocated in a predetermined direction along the transparent plate;

an image reading device mounted in the scanning device and including a light source, the image reading device emitting light from the light source toward the document placed on the transparent plate, and receiving the reflected light from the document, to read the image on the document thereby;

a control unit which controls reading by the image reading device, and a reciprocating movement of the scanning device;

a reference member which is disposed within the exposed area on the transparent plate, and used as a reference when an amount of the light emitted from the light source of the image reading device is adjusted; and

an external-light detector which determines whether external light is entering the reading table, based on at least one value obtained as a result of reading the reference member by the image reading device.

2. The apparatus according to claim 1, wherein the reading the reference member by the image reading device is implemented while the light source is on.

3. The apparatus according to claim 1, wherein the reading the reference member by the image reading device is implemented while the light source is off.

4. The apparatus according to claim 1, wherein the reference member has at least one area having a reflectivity;

and the external-light detector makes the determination based on a value obtained by reading the area.

5. The apparatus according to claim 4, wherein the reference member has a plurality of areas having respective reflectivities, and the external-light detector makes the determination based on a plurality of values obtained by reading the respective areas.

6. The apparatus according to claim 1,

wherein the reference member has a white area and a black area that are arranged in the direction of the reciprocation of the scanning device,

and wherein the external-light detector determines that external light is entering the reading table when a difference between values obtained by reading the white area and the black area, respectively, by the image reading device while the light source is off, is not smaller than a predetermined threshold.

7. The apparatus according to claim 1, wherein the external-light detector determines that external light is entering the reading table when the value obtained by reading the reference member by the image reading device is outside a predetermined range.

8. The apparatus according to claim 7,

wherein the reference member has a plurality of areas having respective reflectivities,

wherein the predetermined range is determined by multiplying by a coefficient a quantity related to a value obtained by reading one of the areas of the reference member whose reflectivity is not the lowest among the areas.

9. The apparatus according to claim 7,

wherein the reference member has a plurality of areas having respective reflectivities,

wherein the predetermined range is determined by multiplying by a coefficient a quantity related to a value obtained by reading one of the areas of the reference member whose reflectivity is not the highest among the areas.

10. The apparatus according to claim 1, wherein the external-light detector determines that external light is entering the reading table when a value obtained by reading the reference member by the image reading device while the light source is on, is outside a predetermined range

11. The apparatus according to claim 1, wherein the external-light detector determines that external light is entering the reading table when a value obtained by reading the reference member by the image reading device while the light source is off is outside a predetermined range.

12. The apparatus according to claim 1,

wherein the control unit adjusts an output of the image reading device such that when the image reading device reads the reference member while the document holding member is closed, the output of the image reading device substantially takes a maximum value in a predetermined range of the output of the image reading device,

and wherein the external-light detector determines that external light is entering the reading table, when (a) the value of the output is obtained by reading each unit area of the reference member by the image reading device while the light source emits light of an amount corresponding to the adjusted output, (b) the unit areas whose values are not smaller than the maximum value in the predetermined range are counted, and (c) the count is not smaller than a predetermined reference number.

13. The apparatus according to claim 1, wherein the reference member is interposed between the transparent plate and an exposed member which is disposed on the transparent plate within the exposed area.

14. The apparatus according to claim 13, wherein the exposed member is a partitioning member which divides the exposed area into a plurality of sections.

15. The apparatus according to claim 14, wherein the partitioning member divides the exposed area into a fed-document reading surface where the image reading device reads an image on a sheet document as fed in a predetermined feeding direction, and a stationary document reading surface where the image reading device reads an image on a document fixed in position on the transparent plate.

16. The apparatus according to claim 14,

wherein the document holding member includes an automatic document feeder which feeds the sheet document set in a document supply tray to the fed-document reading surface and then ejects the sheet document onto a catch tray,

and wherein the partitioning member has a guide surface on a side thereof opposed to the document holding member, the guide surface guiding the sheet document yet to be read, to the fed-document reading surface.

17. The apparatus according to claim 14,

wherein the document holding member includes an automatic document feeder which feeds the sheet document set in a document supply tray to the fed-document reading surface and then ejects the sheet document onto a catch tray,

and wherein the partitioning member has a guide surface on a side thereof opposed to the document holding member, the guide surface guiding the sheet document having been read, from the fed-document reading surface to the catch tray.

18. The apparatus according to claim 1, wherein the image reading device is an image sensor of close-contact type.