The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 28, 1992
Filed:
Dec. 04, 1990
Takashi Shiraishi, Tokyo, JP;
Masao Yamaguchi, Yokohama, JP;
Ken Omura, Tokyo, JP;
Naruhito Yoshida, Yokohama, JP;
Kabushiki Kaisha Toshiba, Kawasaki, JP;
Abstract
In an optical unit incorporated in a laser beam printer, a laser beam generated by a laser diode is converted by a group of conversion lenses into a laser beam having a predetermined-size cross section. The laser beam is directed toward a photosensitive body by a scanner unit, so as to scan the photosensitive body. A focusing lens allows the rotataing angle of the reflecting faces of the scanner unit to correspond to a desirable point on the surface of the photosensitive body. In other words, the rotating angle is made to correspond to the distance between the optical axis center determined with respect to a main scanning direction and a point to which the laser beam is irradiated for scanning. The conversion lenses include at least one aspheric glass lens. The conversion lenses further includes a pair of plastic lenses which have substantially the same power and opposite polarities with respect to either the main scanning direction or a subscanning direction. Among the lenses mentioned above, that lens which is located closest to the glass lens is integral with the laser diode. The focusing lens is formed of a material having substantially equivalent characteristics to those of the paired plastic lenses.