SCANNING OPTICAL DEVICE AND IMAGE FORMING APPARATUS USING IT

摘要

PROBLEM TO BE SOLVED: To obtain a scanning optical system which obtains a highly uniform, high grade image in which ununiform pitch is lessened over the entire effective image-area and to provide an image forming apparatus using the system. SOLUTION: The scanning optical device includes: a 1st optical system which converts a luminous flux emitted from a light source means; a second optical system which converts the luminous flux into a luminous flux extending longitudinally in a main scanning direction; a deflection element which deflects and scans the luminous flux; and a scanning optical system which guides the deflected luminous flux onto a face to be scanned. The luminous flux emitted from the light source means enters the a sub-scanning cross-section at an angle to the deflected face of the deflection element. When the deflection face of the deflection element inclines, an image height located nearest to the light source means among the image heights that do not cause an illumination position change on the face to be scanned is assumed to be Ym∞, and the maximum image height on the face to be scanned is assumed to be L (a positive sign). In the case, the power of the scanning optical system in the sub-scanning direction is set to 0.7Lm∞≤1.0L(the sign of the image height is positive on the light source means side). COPYRIGHT: (C)2004,JPO&NCIPI