To obtain a device which hardly generates the clearances of the joint part of scanning laser beams by forming non-telecentric systems which are changed in the incident angles of laser beams with a rotary medium to be scanned according to scanning positions and making the incident angles on the joint side of the laser scanning optical system larger than that on the end side.
A pair of the laser scanning optical systems are formed as the non-telecentric systems which are changed in the incident angles of the scanning laser beams with the photoreceptor drum by the scanning positions. The scanning laser beams by a pair of the laser scanning optical systems are arranged symmetrically with the center on the joint side of both. The incident angles of both scanning laser beams with the photoreceptor drum are defined as θ on the joint side and β on the end side and are so set as to attain θ>β. If the incident angles on the joint side are set larger (approximate to 90°C), the occurrence of the clearance and overlap at the joint of both scanning laser beams is substantially prevented when an error occurs in the position of the photoreceptor drum.
TAKASUGI EIJI
KIKUCHI SHINJI
SATO TSUTOMU
SAITO HIROYUKI
ARAKI YOSHIYUKI
IIMA MITSUNORI
SASAKI TAKASHI
IIZUKA TAKAYUKI
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