Rotor and polygon scanner that incorporates the rotor

A rotor comprising:

• means for rotating a polygon mirror on a shaft including means for supporting the shaft without contacting the shaft;
• means for maintaining a position of the shaft in a rotating shaft direction including means for contacting the shaft along the rotating shaft direction;
• and
• means for engaging an inner surface of the shaft so as to maintain a position of the shaft in a direction perpendicular to the rotating shaft direction, said means for engaging including,
• holding means for pressing, positioning and holding the shaft from a position opposite to where said means for contacting the shaft actually contacts the shaft.

A self acting air bearing polygon scanner, comprising:

• a polygon mirror;
• a radial self-acting air bearing;
• an axial bearing;
• a rotor having a hollow rotatable shaft that is supported by said axial bearing and said radial self-acting air bearing without contacting the radial self-acting air bearing, said polygon mirror being held to the hollow rotatable shaft;
• and
• a motor that drives the rotor in a rotary direction, wherein
• a contact portion of the rotor is configured to maintain a position of a rotating member in a rotating shaft direction by contacting the rotating member along the rotating shaft direction, and
• an engage portion of said rotor engages an inner surface of the rotating member and is configured to maintain a position of the rotating member in a direction perpendicular to the rotating shaft direction, said engage portion having
• a holding portion with an extension that extends in a peripheral direction, said extension including at least one of
• plural extension members, and
• a single integral extension portion, wherein
• a portion of said extension being disposed against the inner surface of the rotating member, and
• said extension being deformed in a radial direction so as to press, position and hold the rotating member from a side opposite to the contact portion.