Image reading apparatus and image reading module

• US 7,518,763 B2
• Filed: 09/10/2004
• Issued: 04/14/2009
• Est. Priority Date: 01/23/2004
• Status: Expired due to Fees

• Current Assignee: Fuji Xerox Company Limited (Xerox Holdings Corp.)
• Original Assignee: Fuji Xerox Company Limited (Xerox Holdings Corp.)
• Inventors: Hamasuna, Shunsuke, Shiraishi, Ryuuichi, Mikuni, Yuichi
• Primary Examiner(s): Lee; Cheukfan
• Application Number:
  US10/937,332
• Publication Number:
  US 20050162712A1
• Time in Patent Office: 1,677 Days
• Field of Search: 358/483, 358/482, 358/496, 358/498, 358/497, 358/494, 358/474, 358/484, 358/487, 358/506, 358512-514, 358/505, 358/475, 358/509, 358/408, 250/208.1, 250/216, 250/239, 250234-236, 399/211, 399/212, 399/367, 399/364, 355/23, 382/101, 382/318, 382/312
• US Class Current: 358/475
• CPC Class Codes: H04N 1/02815 Means for illuminating the original, not specific to a particular type of pick-up head
• CPC Class Codes: H04N 1/02895 Additional elements in the illumination means or cooperating with the illumination means, e.g. filters H04N1/02885 takes precedence; optical elements other than lenses per se G02B5/00
• CPC Class Codes: H04N 1/1215 Feeding using one or more cylindrical platens or rollers in the immediate vicinity of the main scanning line
• CPC Class Codes: H04N 1/193 using electrically scanned linear arrays , e.g. linear CCD arrays
• CPC Class Codes: H04N 1/203 Simultaneous scanning of two or more separate pictures , e.g. two sides of the same sheet refeeding a sheet for double-sided scanning H04N1/00572
• CPC Class Codes: H04N 1/2032 of two pictures corresponding to two sides of a single medium refeeding a sheet for double-sided scanning H04N1/00572

Abstract

A scanner is provided with an illumination lamp for emitting light to a first side of a document from one side of a transfer path and a CCD image sensor for receiving light reflected from the first side of the document, and a CIS provided in a document feeder is provided with an LED for emitting light to a second side of the document from the other side of the transfer path and a line sensor for receiving light reflected from the second side of the document. The illumination lamp is a xenon lamp, and the LED is a white LED having emission characteristics different from those of the xenon lamp. To the CIS, a filter is attached, which brings emission characteristics of light emitted from the LED onto a document closer to those of light emitted from the illumination lamp onto the document.

Claims

1. An image reading apparatus comprising:

a first reading unit that captures an image on a first side of a document, the first reading unit including a first light source for emitting light to the first side of the document from one side of a transfer path on which the document is conveyed and a first sensor for receiving light reflected from the first side of the document;

a second reading unit that captures an image on a second side of the document, the second reading unit including a second light source, which has emission characteristics different from those of the first light source, for emitting light to the second side of the document from the other side of the transfer path and a second sensor for receiving light reflected from the second side of the document; and

a filter that is provided between the second light source and the transfer path and brings the emission characteristics of the light emitted from the second light source onto the document closer to those of the light emitted from the first light source onto the document.

2. The image reading apparatus according to claim 1, wherein

the first light source is a xenon lamp, and

the second light source is a white LED.

3. The image reading apparatus according to claim 1, wherein

the first sensor is a first image sensor for capturing the light reflected from the first side of the document through a minification optical system, and

the second sensor is a second image sensor for capturing the light reflected from the second side of the document from a distance shorter than that of the first sensor.

4. The image reading apparatus according to claim 1, wherein the filter simultaneously serves as a cover for protecting the second reading unit.

5. The image reading apparatus according to claim 1, further comprising:

a main body; and

a document feeder that is provided separately from the main body in a manner capable of being opened and closed with respect to the main body, wherein

the first reading unit is provided in the main body, and

the second reading unit is provided in the document feeder.

6. The image reading apparatus according to claim 5, wherein the document feeder further includes an inverting transfer path for inverting front and back sides of a document whose image has been captured by the first sensor and conveying the document to the transfer path.

7. The image reading apparatus according to claim 1, further comprising:

an image reading control unit that controls the first sensor and the second sensor to read the first side and the second side of the document when a color reading of the document is specified, and controls the first sensor to read the first side and the second side of the document when a monochrome reading of the document is specified.

8. An image reading apparatus comprising:

a first reading unit that captures an image on a first side of a document as at least one of a color image and a monochrome image, the first reading unit including a first white light source for emitting light to the first side of the document from one side of a transfer path on which the document is conveyed and a first sensor for receiving light reflected from the first side of the document; and

a second reading unit that captures an image on a second side of the document as a monochrome image, the second reading unit including a second white light source for emitting light to the second side of the document from the other side of the transfer path and a second sensor for receiving light reflected from the second side of the document, wherein a wavelength distribution of the first white light source is different from a wavelength distribution of the second white light source, wherein the second reading unit further includes a filter for matching a wavelength distribution of at least one of the light emitted from the second white light source onto the document and the light reflected from the second side of the document with a wavelength distribution of the light emitted from the first white light source.

9. The image reading apparatus according to claim 8, wherein the first white light source emits the light by means of gas discharge, and the second white light source emits the light by means of electroluminescence.

10. The image reading apparatus according to claim 8, further comprising

a main body;

and

a document feeder that is provided separately from the main body in a manner capable of being opened and closed with respect to the main body, wherein

the first reading unit is provided in the main body, and

the second reading unit is provided in the document feeder.

11. The image reading apparatus according to claim 10, wherein the document feeder further includes an inverting transfer path for inverting front and back sides of a document whose image has been captured by the first sensor and conveying the document to the transfer path.

12. The image reading apparatus according to claim 8, further comprising:

an image reading control unit that controls the first sensor and the second sensor to read the first side and the second side of the document when a color reading of the document is specified, and controls the first sensor to read the first side and the second side of the document when a monochrome reading of the document is specified.

13. An image reading module comprising:

a white LED that emits light to a document;

a monochrome line sensor that captures light emitted from the white LED and reflected from the document;

a housing that houses the white LED and the monochrome line sensor; and

a filter that corrects a profile of at least one of the light emitted from the white LED and the light reflected from the document to a predetermined profile, wherein the filter brings emission characteristics of the light emitted from the white LED onto the document closer to those of light emitted from a light source that is different from the white LED in the emission characteristics onto the document.

14. The image reading module according to claim 13, further comprising a selfoc lens provided in the housing, which condenses the light reflected from the document and outputs the condensed light to the monochrome line sensor.

15. The image reading module according to claim 13, wherein the white LED generates white light by an LED, which emits one of blue light and light having a near-ultraviolet wavelength, and a fluorescent material that fluoresces based on the emission of the LED.