JP2010072049A5 - - Google Patents

Claims (12)

A plurality of light source means, an incident optical system for converting a condensing state of a plurality of light beams emitted from the plurality of light source means, a deflection means for deflecting and scanning a plurality of light beams emitted from the incident optical system, In a scanning optical device having an imaging optical system that forms an image on a scanned surface corresponding to each light beam by a plurality of light beams deflected and scanned by a deflecting surface of a deflecting unit,
One deflecting surface of the deflecting unit deflects and scans a plurality of light beams in the same direction, and scans a corresponding scanned surface with each light beam, and a plurality of imaging optical systems corresponding to the scanned surfaces. Of these, an imaging optical system that forms an image on the scanning surface physically closest to the deflecting means is a second imaging optical system, and an image is formed on the scanning surface that is physically farthest on the deflecting means. When the image optical system is the first imaging optical system, the imaging optical element that is optically closest to the scanned surface among the imaging optical elements constituting the first imaging optical system is the first imaging optical system. When the imaging optical element that is optically closest to the scanned surface among the imaging optical elements that constitute the second imaging optical system is the second imaging optical element.
Of the distance from the deflecting surface of the deflecting means to the first imaging optical element and the distance from the deflecting surface of the deflecting means to the second imaging optical element, the sub- element of the imaging optical element having the shorter distance. The refractive power in the scanning direction is φa, and the distance is long among the distance from the deflection surface of the deflection unit to the first imaging optical element and the distance from the deflection surface of the deflection unit to the second imaging optical element. When the refractive power in the sub-scanning direction of the other imaging optical element is φb,
φa <φb
A scanning optical device characterized by satisfying the following conditions: The distance from the first imaging optical element closest to the surface to be scanned optically of the first imaging optical system to the deflection surface of the deflecting means is L1a, and is the most optical of the second imaging optical system. When the distance from the second imaging optical element close to the surface to be scanned to the deflection surface of the deflection means is L1b,
L1a <L1b
The scanning optical apparatus according to claim 1, wherein the following condition is satisfied. The scanning optical device according to claim 1, wherein the second imaging optical element is optically disposed on the deflection unit side with respect to the optical path bending unit closest to the surface to be scanned. . The deflection means comprises a rotary polygon mirror having a plurality of deflection surfaces, and two of the plurality of deflection surfaces facing the rotation axis of the rotary polygon mirror are emitted from the plurality of light source means. has been provided with a plurality of light beams are incident, wherein the plurality of light beams, according to claim 1 to 3, characterized in that scanning the plurality of the scan surface that face each other across the rotation axis of said rotary polygonal mirror The scanning optical device according to any one of the above. In the sub-scan section, the plurality of light beams incident on one deflection surface of the deflection means according to claim 1 to 4, characterized in that it is obliquely incident to the deflecting surface of said rotary polygonal mirror The scanning optical device according to any one of the above. A plurality of oblique incidence angles in the sub-scanning section to the deflection surface of the light beam incident on one deflecting surface of said deflecting means, to any one of claims 1 to 5, characterized in that absolute values are equal The scanning optical device described. Each of the plurality of imaging optical systems includes a plurality of imaging optical elements,
Among imaging optical elements constituting the plurality of imaging optical systems, the closest imaging optical element to the deflecting means, of claims 1 to 6, characterized in that it is shared by a plurality of imaging optical systems The scanning optical device according to any one of the above. The light beam passing through the second imaging optical element, the scanning optical apparatus according to any one of claims 1 to 7, wherein the non-intersecting in the sub-scanning section. When the imaging magnification in the sub-scanning direction of the first imaging optical system is βsa, and the imaging magnification in the sub-scanning direction of the second imaging optical system is βsb,
1.0 <| βsa | <2.5
1.1 <| βsa / βsb | <1.3
The scanning optical apparatus according to any one of claims 1 to 8, characterized by satisfying the following condition. The optical path bending means is disposed in the optical path of the first imaging optical system , and two optical path bending means are disposed in the optical path of the second imaging optical system. the scanning optical apparatus according to any one of 1 to 9. A scanning optical apparatus each according to any one of claims 1 to 10, a plurality of photosensitive member disposed on the plurality of surface to be scanned, of the photosensitive member by a light beam scanned by said scanning optical device A plurality of developing units that develop the electrostatic latent image formed thereon as a toner image, a plurality of transfer units that transfer the developed toner image to a transfer material, and the transferred toner image fixed to the transfer material An image forming apparatus comprising: a fixing device that causes the image forming apparatus to have a fixing device. 12. The image forming apparatus according to claim 11, further comprising a print controller that converts color signals input from an external device into image data of different colors.