Optical scanning device and image forming apparatus

摘要

An optical scanning device includes a screw shaft, a holing member, a cleaning member, and a drive mechanism. The screw shaft is arranged along a covering. The screw shaft includes a main body portion and two rotary shaft portions provided on opposite ends of the main body portion integrally with the main body portion. A screw groove is formed in the main body portion. A protrusion engaging with the screw groove is formed on the holding member. Rotation of the screw shaft moves the holding member along the screw shaft. The cleaning member is held by the holding member. The drive mechanism drives and rotates the screw shaft, while moving the screw shaft in a direction reverse to a movement direction of the holding member.

主权项

1. An optical scanning device comprising:
a casing in which a light emitting port is formed; a covering configured to block the light emitting port and to transmit light; a screw shaft arranged along the covering and including a main body portion and two rotary shaft portions provided on opposite ends of the main body portion integrally with the main body portion, a screw groove being formed in the main body portion, and each of the rotary shaft portions having an outer peripheral surface continuing to a bottom surface of the screw groove in the main body portion; two bearings provided at the casing and configured to support the rotary shaft portions rotatably and support the rotary shaft portions moveably in an axial direction of the screw shaft; a holding member on which a protrusion engaging with the screw groove is formed, the holding member being configured to move along the screw shaft by rotation of the screw shaft; a cleaning member held by the holding member and configured to clean a surface of the covering by movement of the holding member; and a drive mechanism configured to drive and rotate the screw shaft and to move the screw shaft in a direction reverse to a movement direction of the holding member, wherein the protrusion is located on the outer peripheral surface of one of the two rotary shaft portions and comes off from the screw groove before the drive mechanism starts driving the screw shaft, when the drive mechanism starts driving the screw shaft to rotate the screw shaft in a first rotation direction, the screw shaft moves in a first direction in which the screw groove receives the protrusion to cause the protrusion to engage with the screw groove before the holding member starts moving, and when the drive mechanism further rotates the screw shaft in the first rotation direction after engagement of the protrusion with the screw groove, the screw shaft further moves in the first direction and the protrusion is guided by the screw groove to move the holding member in a second direction reverse to the first direction.