Title:
IMAGE FORMING DEVICE
Document Type and Number:
Japanese Patent JPH01120578
Kind Code:
A
Abstract:
PURPOSE:To attain almost a constant dot diameter in any scanning position and to eliminate the variance of transfer images and the unevenness of variable density by changing beam output intensity in response to the scanning positions when beam spot diameters vary in scanning positions. CONSTITUTION:A cylindrical lens 6 linearly condenses laser beams from the semiconductor 1 of an image forming device on a polygon mirror 2, and an ftheta lens 4 image-forms the beams reflected by the mirror 2 on a photosensitive drum 3. By rotating the mirror twice, the drum 3 is scanned. A photodetector 8 receives laser beams, and a synchronization detecting signal generating circuit 40 outputs synchronization detecting signals. Based on those signals, an image element clock generating circuit 41 generates image element clocks, and a scanning position discriminating circuit 39 discriminates the scanning position of the drum 3 with the aid of those clocks. Correction is performed by a correcting value set to an output intensity correcting circuit 38, and an LD driving circuit 18 is controlled by outputs from an output intensity control circuit 25 and a pulse width control circuit 42.
Inventors:
KANEKO YOSHIO
NAGASAWA KIYOTO
MAMA TAKASHI
ASADA KENICHIRO
FUJIOKA NAONOBU
MIZUNO AKINORI
NAGASAWA KIYOTO
MAMA TAKASHI
ASADA KENICHIRO
FUJIOKA NAONOBU
MIZUNO AKINORI
Application Number:
JP27833987A
Publication Date:
May 12, 1989
Filing Date:
November 05, 1987
Export Citation:
Assignee:
RICOH KK
International Classes:
B41J2/44; G03G15/04; H04N1/04; H04N1/113; H04N1/23; (IPC1-7): G03G15/04; H04N1/04; H04N1/23
Attorney, Agent or Firm:
Kenjiro Take
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