To accurately position an image forming mirror on which an off-axial reflection surface is formed so as to absorb the thermal expansion of the mirror caused by temperature rise.
The image forming mirror on which the off-axial surface is formed is independently provided with means for respectively positioning the longitudinal direction, the lateral direction and reflection surface direction of the mirror. A hole with which the longitudinal positioning means and the lateral positioning means are engaged has a gap for absorbing the temperature rise of the image forming mirror in a direction orthogonal to the engagement direction when both the positioning means are engaged. The reflection surface direction of the image forming mirror is positioned by causing an abutting surface arranged on the reflection surface side to abut on a mirror supporting member.
MIURA YUKIHIRO
AOYAMA TAKESHI
KISHI TAKEHIRO
IWATA HYOE
Yuichi Uchio