Illumination Device, Illumination Method, Image Read Device, Image Read Method, Image-Forming Device, and Image-Forming Method

• US 20080316548A1
• Filed: 03/20/2006
• Published: 12/25/2008
• Est. Priority Date: 03/18/2005
• Status: Active Grant

• Current Assignee: Ricoh Company Limited
• Original Assignee: Ricoh Company Limited
• Inventors: Yamauchi, Satoshi, Nakashige, Fumihiro
• Granted Patent: US 8,169,672 B2
• Time in Patent Office: Days
• US Class Current: 358/475
• CPC Class Codes: G02B 27/0905 Dividing and/or superposing multiple light beams
• CPC Class Codes: G02B 27/0961 Lens arrays lens arrays per se G02B3/0006
• CPC Class Codes: G03B 27/54 Lamp housings; Illuminating means
• 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 1/02865 using an array of light sources or a combination of such arrays, e.g. an LED bar
• 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 1/1017 the main-scanning components remaining positionally invariant with respect to one another in the sub-scanning direction
• CPC Class Codes: H04N 1/193 using electrically scanned linear arrays , e.g. linear CCD arrays

Abstract

A disclosed image scanning device illuminates a document with a light source, focuses light reflected from the document on an image sensor to obtain one-dimensional images of the document, and obtains a two-dimensional image of the document from the one-dimensional images. The device includes an illumination lens for dividing a light beam emitted from the light source into multiple light beams and a combining unit for combining the multiple light beams on the document. A disclosed image scanning method includes the steps of illuminating a document with a light source; focusing light reflected from the document on an image sensor to obtain one-dimensional images of the document; and obtaining a two-dimensional image of the document from the one-dimensional images. In this method, a light beam from the light source is divided into multiple light beams and the multiple light beams are combined on the document. A disclosed image forming apparatus includes the image scanning device.

Claims

1. An image scanning device that illuminates a document with a light source unit, focuses light reflected from the document on an image sensor using an imaging lens to obtain one-dimensional images of the document, and obtains a two-dimensional image of the document from the one-dimensional images, comprising:

an illumination lens including multiple lenses and configured to divide a light beam emitted from the light source unit into multiple light beams; and

a combining unit configured to combine the multiple light beams on the document.

2. The image scanning device as claimed in claim 1, wherein

the light source unit includes multiple light sources;

and

the number of the light sources in a direction in which the light beam is divided and the number into which the light beam is divided are not equal.

3. The image scanning device as claimed in claim 1, wherein

the light source unit includes multiple light sources;

some of the light sources are arranged in a direction in which the light beam is divided; and

other ones of the light sources are arranged in a direction that is orthogonal to the direction in which the light beam is divided so as to complement distribution of light beams from the some of the light sources.

4. The image scanning device as claimed in claim 1, wherein

the light source unit includes multiple light sources;

and

a light beam from each of the light sources is substantially collimated and then divided into multiple light beams by the illumination lens.

5. The image scanning device as claimed in claim 1, wherein an LED is used for the light source unit.

6. The image scanning device as claimed in claim 1, wherein a combining lens is used as the combining unit.

7. The image scanning device as claimed in claim 1, wherein illuminating light emitted from the light source unit to illuminate an imaging area and imaging light reflected from the imaging area are reflected back by a same reflective surface.

9. An image forming apparatus including the image scanning device as claimed in claim 1.

8. (canceled)

10. An illuminating device for illuminating a target with light emitted from a light source unit, comprising:

at least one light-beam illumination element configured to obtain multiple light beams from the light emitted from the light source unit and to direct the multiple light beams to the target in at least one plane.

11. The illuminating device as claimed in claim 10, further comprising:

at least one light-beam focusing element configured to focus the multiple light beams on the target in at least one plane.

12. The illuminating device as claimed in claim 10, further comprising:

at least one optical element configured to combine the multiple light beams on the target in a first plane and to focus the multiple light beams on the target in a second plane that is different from the first plane.

13. The illuminating device as claimed in claim 10, wherein

the at least one plane includes a first plane and a second plane that is different from the first plane;

and

the at least one light-beam illumination element includes

a first light-beam illumination element configured to obtain multiple first light beams from light emitted from the light source unit in the first plane and to direct the multiple first light beams to the target, and

a second light-beam illumination element configured to obtain multiple second light beams from light emitted from the light source unit in the second plane and to direct the multiple second light beams to the target.

14. The illuminating device as claimed in claim 10, further comprising:

at least one light-beam dividing element configured to divide the light emitted from the light source unit into the multiple light beams in at least one plane.

15. The illuminating device as claimed in claim 14, wherein a distance between the light-beam dividing element and the light-beam illumination element is larger than a focal length of the light-beam dividing element and a focal length of the light-beam illumination element.

16. The illuminating device as claimed in claim 10, wherein

the light source unit includes a first light source configured to emit first light with a wavelength within a first wavelength range and a second light source configured to emit second light with a wavelength within a second wavelength range;

and

the first light source and the second light source are arranged, in at least one plane, such that a peak position of illuminance of the first light on the target becomes different from a peak position of illuminance of the second light on the target.

17. The illuminating device as claimed in claim 10, further comprising:

a wavelength dispersing element configured to disperse the light emitted from the light source unit into light beams of different wavelengths in at least one plane.

19. An image scanning device that illuminates a document having an image formed thereon with light emitted from a light source and scans the image by receiving light reflected from the document, comprising:

the illuminating device as claimed in claim 10.

18. (canceled)