Patent Number: 7,133,220

Title: Lens for reading an original, method and apparatus for reading an original, and image forming apparatus

Abstract: A lens for reading an original, comprises five lenses as a whole including two positive and two negative lenses, an aspherical surface provided on at least one surface of the five lenses, a construction of four lens groups for five lenses which include a cemented lens constructed by cementing one of the positive lenses and one of the negative lenses, an aperture stop disposed between a second and third lens groups, and the cemented lens disposed adjacent to the aperture stop.

Inventors: Nishina; Kiichiro (Ohta-ku, JP)

Assignee: Ricoh Company, Ltd.

International Classification: G02B 9/36 (20060101)

Expiration Date: 2019-11-07 0:00:00