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AssigneeMinolta Co., Ltd.
InventorsYoshihiro Inagaki, Nobuo Kanai, Jun Kohsaka, Kenji Takeshita, Keiji Ogoh, Hidenari Tachibe
Estimating the term…
A laser beam scanning optical apparatus which has a laser source unit, a collimator lens, a cylindrical lens, a polygon mirror and a scanning lens with an f.theta. function. The collimator lens is a bifocal lens, and because of the bifocal collimator lens, a part of the laser beam is focused on a point before the surface of a photosensitive member, and another part of the laser beam is focused on a point after the surface of the photosensitive member. Also, the cylindrical lens can be a bifocal lens. In this case, even when the magnification ratio in the sub scanning direction is designed small, the focal length of the cylindrical lens does not have to be lengthened.
A scanning optical apparatus comprising:
A method of inhibiting a change in diameter of a beam spot on a scanning surface with a change in temperature in a scanning optical apparatus which deflects a laser beam emitted from a laser source with a deflector to scan the laser beam on a scanning surface and focuses the laser beam on the scanning surface with a scanning optical element, comprising the steps of:
Dependencies are inferred from the claim text.