A rotary switch actuator adjacent to a sheet transport path, said switch including a substrate, a horseshoe sensor having an upper arm including a light source and a lower arm incorporating a light sensor, said light source and light sensor having a common sensing axis, a first actuator arm extending into said transport path, a second actuator arm extending into said common sensing axis, a hub assembly mounted for rotation about a pivot post fixed in position on said substrate, said hub assembly having a plurality of helical segments which mate with helical segments formed on said substrate, a spring member connected between said hub member and said substrate, and wherein upon rotation of said switch by a paper sheet contacting said first arm, said second arm is moved out of the common sensing axis and generates a detected paper signal and said spring is stretched to create an energy force and upon movement of the paper sheet out of contact with the first activator arm, said switch is rotated to the first position by the action of the stored energy of said spring and wherein said helical surfaces slide upward to release the stored energy of the spring so that the second arm does not bounce back out of the common sensed axis.