SURFACE-EMITTING LASER ARRAY, OPTICAL SCANNING DEVICE, AND IMAGE FORMING DEVICE

• US 20100214633A1
• Filed: 07/04/2008
• Published: 08/26/2010
• Est. Priority Date: 07/13/2007
• Status: Active Grant

• Current Assignee: Ricoh Company Limited
• Original Assignee: Ricoh Company Limited
• Inventors: Ichii, Daisuke, Hayashi, Yoshinori, Sato, Shunichi
• Granted Patent: US 8,179,414 B2
• Time in Patent Office: Days
• US Class Current: 358/510
• CPC Class Codes: B41J 2/45 using light-emitting diode [LED] or laser arrays
• CPC Class Codes: B41J 2/455 using laser arrays , the laser array being smaller than the medium to be recorded
• CPC Class Codes: B41J 2/473 using multiple light beams, wavelengths or colours
• CPC Class Codes: G02B 26/123 Multibeam scanners, e.g. using multiple light sources or beam splitters
• CPC Class Codes: G03G 15/04072 by laser
• CPC Class Codes: G03G 15/0435 by introducing an optical element in the optical path, e.g. a filter
• CPC Class Codes: G03G 15/326 by application of light, e.g. using a LED array
• CPC Class Codes: G03G 2215/0404 Laser
• CPC Class Codes: G03G 2215/0421 Plurality of devices for producing the image (excluding dedicated erasing means)
• CPC Class Codes: H01S 5/423 having a vertical cavity
• CPC Class Codes: H04N 1/0311 using an array of elements to project the scanned image elements onto the photodetectors H04N1/0318 takes precedence
• CPC Class Codes: H04N 1/113 using oscillating or rotating mirrors
• CPC Class Codes: H04N 1/1135 for the main-scan only
• CPC Class Codes: H04N 1/121 Feeding arrangements transporting sheets to or from the scanning position H04N1/0057; control or error compensation of sub-scanning velocity H04N1/0473
• CPC Class Codes: H04N 1/195 the array comprising a two-dimensional array or a combination of two-dimensional arrays
• CPC Class Codes: H04N 1/19515 in two directions
• CPC Class Codes: H04N 2201/03104 Integral pick-up heads, i.e. self-contained heads whose basic elements are a light source, a lens and a photodetector supported by a single-piece frame

Abstract

A surface-emitting laser array includes a plurality of light emitting parts arranged in a two-dimensional formation having two orthogonal directions. When the plurality of light emitting parts are orthogonally projected on a virtual line parallel to one of the two orthogonal directions, a spacing between two of the plurality of light emitting parts along the virtual line is equal to an integral multiple of a predetermined value. The plurality of light emitting parts include a first light emitting part, a second light emitting part adjacent to the first light emitting part, and a third light emitting part adjacent to the second light emitting part, and a spacing between the first and second light emitting parts differs from a spacing between the second and third light emitting parts.

Claims

1. A surface-emitting laser array including a plurality of light emitting parts arranged in a two-dimensional formation having two orthogonal directions,

wherein, when the plurality of light emitting parts are orthogonally projected on a virtual line parallel to one of the two orthogonal directions, a spacing between two of the plurality of light emitting parts along the virtual line is equal to an integral multiple of a predetermined value,

wherein the plurality of light emitting parts include a first light emitting part, a second light emitting part adjacent to the first light emitting part along the virtual line, and a third light emitting part adjacent to the second light emitting part along the virtual line, and a spacing between the first and second light emitting parts differs from a spacing between the second and third light emitting parts in the one of the two orthogonal directions.

2. The surface-emitting laser array of claim 1, wherein the first, second and third light emitting parts are arranged at a central portion of the two dimensional array in the one of the two orthogonal directions, the second and third light emitting parts are located near end portions of the two dimensional array in the other direction of the two orthogonal directions, and the spacing between the second and third light emitting parts is smaller than the spacing between the first and second light emitting parts in the one of the two orthogonal directions.

3. The surface-emitting laser array of claim 1, wherein a spacing between two of the plurality of light emitting parts located at a central portion of the two-dimensional array is larger in the one of the two orthogonal directions than a spacing between two of the plurality of light emitting parts located at an end portion of the two-dimensional array.

4. The surface-emitting laser array of claim 1, wherein a spacing between two of the plurality of light emitting parts located at a central portion of the two-dimensional array is larger in the other direction of the two orthogonal directions than a spacing between two of the plurality of light emitting parts located at an end portion of the two-dimensional array.

5. The surface-emitting laser array of claim 1, wherein the plurality of light emitting parts include a plurality of rows of light emitting parts, each row including at least two light emitting parts arranged in the one of the two orthogonal directions, are arranged in the other direction of the two orthogonal directions, and the number of the light emitting part rows is larger than the number of the light emitting parts contained in one light emitting part row.

6. The surface-emitting laser array of claim 1, wherein two light emitting parts located at ends of the two-dimensional array in the one of the two orthogonal directions are arranged at positions other than ends of the two-dimensional array in a direction perpendicular to the one of the two orthogonal directions.

7. An optical scanning device comprising:

a light source unit including the surface-emitting laser array of claim 1, the light source unit having a main scanning direction and a sub-scanning direction parallel to the two orthogonal directions respectively;

a deflection unit deflecting a plurality of laser beams emitted by the light source unit; and

a scanning optical system focusing the laser beams output from the deflection unit on a scanned surface of a photoconductor.

8. An image forming device comprising the optical scanning device of claim 7 and a photoconductor, wherein the optical scanning device scans a surface of the photoconductor by laser beams output from the optical scanning device, so that an image is formed on the photoconductor surface in accordance with image information of the laser beams.

9. The image forming device of claim 8, wherein the image information is multicolor image information.

10. An image forming device comprising the surface-emitting laser array of claim 1, wherein the surface-emitting laser array is provided as a part of an optical writing unit, the optical writing unit outputting laser beams to a photoconductor when writing image information to the photoconductor.