Image forming apparatus

Details Image forming apparatus Image forming apparatus

1997-08-01

2001-05-22

Le, Que T. (Department: 2878)

Radiant energy

Photocells; circuits and apparatus

Optical or pre-photocell system

C358S474000, C347S241000

Reexamination Certificate

active

06236040

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to image forming apparatus, more particularly, to copiers and printers forming images using a plurality of laser beams.
2. Description of Related Arts
In the conventional image forming apparatus using laser beams, scanning means scans an object surface (a photoconductor) with a plurality of laser beams emitted from a light source to form latent images, and a beam-pitch detector is provided between the light source and the scanning means for correcting a beam pitch (a distance between beams) (see Japanese Examined Patent Publication No. Hei
6
(1994)-94215, Japanese Unexamined Patent Publication No. Sho63(1988)217763, Japanese Unexamined Patent Publication No.Sho60(1985)-166916).
In such image forming apparatus, however, since the beam-pitch detector is placed between the light source and the scanning means, it is impossible to detect a change of the beam pitch which may occur in an optical path from the scanning means to the scanned surface due to thermal expansion of an optical system or other causes. Thus, the beam pitch cannot be sufficiently corrected, and sometimes normal images cannot be formed.
SUMMARY OF THE INVENTION
The present invention provides an image forming apparatus comprising a plurality of light sources emitting beams of light, a photoconductor, scanning means for reflecting the beams of light emitted by the light sources to scan the photoconductor periodically, a light detector for receiving the beams of light from the scanning means to determine a beam pitch between the beams of light, the light detector being provided in a part of an optical path formed between the scanning means and the photoconductor, beam shift means for shifting the beams of light incident on the scanning means from the light sources, and control means for operating the beam shift means so that the beam pitch determined by the light detector becomes a predetermined value.


REFERENCES:
patent: 5299049 (1994-03-01), Saito et al.
patent: 5416505 (1995-05-01), Eguchi et al.
patent: 5724087 (1998-03-01), Sugano et al.
patent: 5786594 (1998-07-01), Ito et al.
patent: 5883385 (1999-03-01), Takahashi et al.
patent: 5926203 (1999-07-01), Shimura et al.
patent: 60166916 (1985-08-01), None
patent: 61245174 (1986-10-01), None
patent: 6321763 (1988-09-01), None

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