US Patent 7876508 Lens drive unit, lens barrel, and image forming device

A lens drive unit is configured to move a lens holding frame to a desired position by the engagement between a cam groove of a rotary cylinder and a cam follower of the lens holding frame. The lens drive unit includes a second linearly-moving guide cylinder arranged between the lens holding frame and a first linearly-moving guide cylinder. The second linearly-moving guide cylinder can be moved in the optical a direction with rotation of the rotary cylinder by the engagement of a cam follower of the second linearly-moving guide cylinder with a second cam groove of the rotary cylinder. The lens holding frame is guided in the optical axis direction by the second linearly-moving guide cylinder and moved in the optical axis direction with rotation of the rotary cylinder by the engagement of a cam follower of the lens holding frame with a first cam groove of the rotary cylinder.