Exposure device for an electrophotographic apparatus

• US 20040227808A1
• Filed: 05/03/2004
• Published: 11/18/2004
• Est. Priority Date: 05/16/2003
• Status: Active Grant

• Current Assignee: Ricoh Printing Systems Limited (Ricoh Company Limited)
• Original Assignee: Hitachi Printing Solutions, Ltd. (Ricoh Company Limited)
• Inventors: Ueno, Hiroshi, Ishizawa, Katsumi
• Granted Patent: US 7,339,603 B2
• Time in Patent Office: Days
• US Class Current: 347/251
• CPC Class Codes: B41J 2/471 using dot sequential main scanning by means of a light deflector, e.g. a rotating polygonal mirror
• CPC Class Codes: G02B 26/124 Details of the optical system between the light source and the polygonal mirror G02B26/123, G02B26/127 take precedence
• CPC Class Codes: G06K 15/1209 Intensity control of the optical beam G06K15/1223 takes precedence

Abstract

An exposure device for an electrophotographic apparatus including one or more laser light sources which expose an image carrier in accordance with a print information signal supplied from an external information processing apparatus, a resolution switching lens, and a switching unit to switch over a low resolution and a high resolution by inserting and extracting the resolution switching lens into and from a laser optical path. Preferably, a light emission time of each of the laser light sources with respect to the print information signal is changeable.

Claims

1. An exposure device for an electrophotographic apparatus comprising:

one or more laser light sources which expose an image carrier in accordance with a print information signal supplied from an external information processing apparatus;

a resolution switching lens; and

a switching unit to switch over a low resolution and a high resolution by inserting and extracting the resolution switching lens into and from a laser optical path,

wherein a light emission time of each of the laser light sources with respect to the print information signal is changeable.

2. An exposure device for an electrophotographic apparatus according to claim 1,

wherein the light emission time of the laser light source with respect to the print information signal is set to a value by which vertical and lateral line widths of each dot are equal to each other.