The disclosure relates to a method and apparatus for providing switching optical filter. The image printing system includes an inputting unit for making reservations for cutting of the photosensitive material by the unit of order. In this manner, the torsional motion of the torsional harmonic cantilever at that harmonic frequency will be largely enhanced by the corresponding torsional resonance. The pins project into a screw hole or the like in the computer drive for releasably securing the computer drive to the chassis.