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:
May. 04, 1993
Filed:
Nov. 14, 1991
Kan Tomita, Tokyo, JP;
Ricoh Company, Ltd., Tokyo, JP;
Abstract
In an optical scanner, an image-forming optical system approximately sets the position of a deflecting/reflecting face of a rotary polygon mirror and the position of a scanned face in a conjugate relation in geometrical optics in a cross scan-corresponding direction. This optical system has a function for converging a deflected light beam onto the scanned face in a main scan-corresponding direction. The optical system is set such that the following condition, W.sub.0 /k.sub.2 <R/D<W.sub.0 /k.sub.1 is satisfied, where R designates a distance between the position of a real image and the position of an image of a light emitting section formed by an image-forming element between a laser diode light source and the scanned face; D designates a diameter of an opening image in the cross scan-corresponding direction with respect to the real image; W.sub.0 designates a waist diameter of the deflected light beam to be obtained between the real image position and the image position of the light emitting section; .lambda. designates a light emitting wavelength of the light source; a wavelength .lambda. is set to 780 nm; k.sub.1 is equal to 0.67.lambda./.lambda..sub. 0 ; and k.sub.2 is equal to 1.1.lambda./.lambda..sub.0.