Multibeam scanning apparatus

• US 6,775,041 B1
• Filed: 04/19/2000
• Issued: 08/10/2004
• Est. Priority Date: 04/20/1999
• Status: Expired due to Term

• Current Assignee: Ricoh Company Limited
• Original Assignee: Ricoh Company Limited
• Inventors: Nakajima, Tomohiro
• Primary Examiner(s): Phan, James
• Application Number:
  US09/552,657
• Time in Patent Office: 1,574 Days
• Field of Search: 359/196-226, 359/738-740, 347/225-261
• US Class Current: 359/204.1
• CPC Class Codes: G02B 26/124 Details of the optical system between the light source and the polygonal mirror G02B26/123, G02B26/127 take precedence
• CPC Class Codes: H04N 1/113 using oscillating or rotating mirrors

Abstract

A multibeam scan apparatus includes a light source having semiconductor laser diodes and coupling lenses arranged in a main scan direction. The semiconductor laser diodes are positioned so that light beams emitted by the semiconductor laser diodes substantially cross each other at a point. A light beam restricting unit shapes the light beams from the laser diodes through the coupling lenses so that the light beams have a given spot size. The light beam restricting unit is positioned close to the above-mentioned point. A scan lens causes the light beams reflected by a polygonal mirror to form images on a scanned surface.

Claims

1. A multibeam scan apparatus comprising:

a light source having a unitary structure including semiconductor laser diodes and coupling lenses arranged in a main scan direction, the semiconductor laser diodes being positioned so that light beams emitted by the semiconductor laser diodes form images on a same area of a scanned surface area and substantially cross each other at a point;

a light beam restricting unit shaping the light beams from the laser diodes through the coupling lenses so that the light beams have a given spot size, the light beam restricting unit being positioned close to the point;

a deflection unit; and

a scan lens causing the light beams reflected by the deflection unit to form images on a scanned surface;

wherein;

the light beam restricting unit is incorporated into each of reflection surfaces of the deflection unit; and

the spot size of the light beams incident to the deflection unit is larger than a size of each of the reflection surfaces in at least the main scan direction.

2. A multibeam scan apparatus comprising:

a light source having semiconductor laser diodes and coupling lenses arranged in a main scan direction, the semiconductor laser diodes being positioned so that light beams emitted by the semiconductor laser diodes substantially cross each other at a point;

a light beam restricting unit shaping the light beams from the laser diodes through the coupling lenses so that the light beams have a given spot size, the light beam restricting unit being positioned close to the point;

a deflection unit; and

a scan lens causing the light beams reflected by the deflection unit to form images on a scanned surface;

wherein;

the light beam restricting unit is incorporated into each of reflection surfaces of the deflection unit; and

the spot size of the light beams incident to the deflection unit is larger than a size of each of the reflection surfaces in at least the main scan direction,

wherein each of the reflection surfaces of the deflection unit has an edge shorter than surfaces of the deflection unit in which the reflection surfaces are formed.

3. A multibeam scan apparatus comprising:

a light source emitting light beams from respective light sources formed in a unitary structure and arranged in a main scanning direction, outgoing beam directions in which the light beams travel being arranged so as to cross each other at a point, and the light beams forming images on a same area of a scanned surface;

a deflection unit deflecting the light beams;

an optical unit causing the light beams from the deflection unit to form images on a scanned surface; and

a light beam restricting mechanism situated close to said point and arranged to shape the light beams, and incorporated into deflection surfaces of said deflection unit to shape the light beams to have a given spot size before the light beams enter said optical unit that forms the images, the light beams incident to the deflection unit having a spot size that is larger than a size of each of the deflection surfaces.

4. A multibeam scan apparatus comprising:

a light source emitting light beams, outgoing beam directions in which the light beams travel being arranged so as to cross each other at a point;

a deflection unit deflecting the light beams;

an optical unit causing the light beams from the deflection unit to form images on a scanned surface; and

a light beam restricting mechanism situated close to said point and arranged to shape the light beams, and incorporated into deflection surfaces of said deflection unit to shape the light beams to have a given spot size before the light beams enter said optical unit that forms the images, the light beams incident to the deflection unit having a spot size that is larger than a size of each of the deflection surfaces,

wherein the light beams emitted by the light source cross each other at a position close to the deflection unit,

wherein each of the deflection surfaces of the deflection unit has an edge shorter than surfaces of the deflection unit in which the deflection surfaces are formed.

5. A multibeam scan apparatus comprising:

a light source emitting light beams, outgoing beam directions in which the light beams travel being arranged so as to cross each other at a point;

a deflection unit deflecting the light beams;

an optical unit causing the light beams from the deflection unit to form images on a scanned surface; and

a light beam restricting mechanism situated close to said point and arranged to shape the light beams, and incorporated into and extending into deflection surfaces of said deflection unit to shape the light beams to have a given spot size before the light beams enter said optical unit that forms the images, the light beams incident to the deflection unit having a spot size that is larger than a size of each of the deflection surfaces,

wherein each of the deflection surfaces of the deflection unit has an edge shorter than surfaces of the deflection unit in which the deflection surfaces are formed.

6. A multibeam scan apparatus comprising:

a light source having a unitary structure including semiconductor laser diodes and coupling lenses arranged in a main scan direction, the semiconductor laser diodes being positioned so that light beams emitted by the semiconductor laser diodes form images on a same area of a scanned surface area and substantially cross each other at a point;

a light beam restricting unit shaping the light beams from the laser diodes through the coupling lenses so that the light beams have a given spot size, the light beam restricting unit being positioned close to the point;

a deflection unit; and

a scan lens causing the light beams reflected by the deflection unit to form images on a scanned surface;

wherein;

the light beam restricting unit is incorporated into each of reflection surfaces of the deflection unit;

the spot size of the light beams incident to the deflection unit is larger than a size of each of the reflection surfaces in at least the main scan direction; and

wherein each of the deflection surfaces of the deflection unit has an edge shorter than surfaces of the deflection unit in which the deflection surfaces are formed.