Abstract: A rotatable polygon mirror includes a plurality of reflecting surfaces provided in parallel to a rotational axis direction, first surface and second surface of polygonal shape perpendicular to the plurality of reflecting surface and of which each side is continued to the plurality of reflecting surfaces. The second surface is opposite to the first surface. A through hole penetrates though the first and second surfaces in parallel to the rotational axis direction and to engage with a rotational shaft of a driving portion. As seen in the rotational axis direction, the through hole has substantially similar shape to the polygonal shape of the first and the second surfaces, and vertexes of the similar shape of the through hole are different in phase from apexes of the polygonal shape of the first and second surfaces with respect to a rotational direction of the polygon mirror.

Abstract: A rotatable polygon mirror molded with a resin includes a plurality of reflecting surfaces provided in parallel to a rotational axis direction, a surface perpendicular to the rotational axis direction; a plurality of gate portions provided on the surface and a recess-projection on the surface. The recess-projection has at least one shape of a recess shape recessed in the rotational axis from the and a projection shape projected from the surface as viewed in a direction perpendicular to the rotational axis direction. The recess-projection is provided in a virtual straight line with equal distances from two of the adjacent gate portions with respect to a rotational direction of the rotatable polygon mirror and connecting a rotation center of the rotatable polygon mirror and a boundary of two of the adjacent reflecting surfaces with respect to the rotational direction.

Abstract: An optical deflector includes a rotatable polygon mirror and an urging member to urge the rotatable polygon mirror toward a driving unit to fix the rotatable polygon mirror to the driving unit. The urging member includes an annular shape portion having an annular shape surface contacting the rotatable polygon mirror and a plurality of arm portions integrally formed with the annular shape portion. The plurality of the arm portions radially extend from an outer circumference of the annular shape portion, are disposed at equal intervals with respect to a rotational direction with a rotation center of the rotatable polygon mirror, and are pressed by a restricting member.

Abstract: A substrate treating apparatus for successively treating substrates includes a body having a carrying unit for carrying the substrate along a carrying surface. The carrying surface is inclined in a plane perpendicular to the carrying direction of the substrate. The body supplies a treating liquid to the substrate being carried for treating the substrate. A receiving station is disposed upstream of the body for changing the posture of the substrate from a horizontal posture to an inclined posture corresponding to the inclination of the carrying surface, and for forwarding the substrate onto the carrying unit. In addition, a delivering station is disposed downstream of the body for returning the substrate forwarded from the carrying unit in the inclined posture to the horizontal posture.