Setsuo Minami

Scanning Optical System Of The Canon Laser Beam Printer

We describe studies on the scanning optical system for compact and inexpensive Canon laser beam printer (which we call LBP). Based on Canons historically accumulated laser scanning optical technologies, our originally developed scanning optical system has the two functions of fθ-characteristic and deflection error compensation (we call the scanning optical system fθ-DEC), comprising a polygonal mirror scanner and toric lens as key components. As for the design, compactness and inexpensiveness of the fθ-DEC scanning optical system was investigated based on our theoretical and analytical study on fθ-lens for LBPs. On the manufacturing side, exclusive manufacturing equipment was developed for each of the above mentioned key components for effective mass production. In this paper, the theory, design, and manufacturing technologies for our fθ-DEC scanning optical system are presented. In addition, as an application example, Canon LBP-CX is introduced, where the above technologies have been integrated.

Optical Lens System For Laser Beam Printer

In the scanning optical system for laser beam printer, so-called f-0 lens is utilized to provide a scanning spot of constant velocity from deflected light beam having constant angular velocity. Then, f-8 lens is designed to have proper amount of residual distortion. One important point at the optical design of such kind of optical system is to find out the relationship between distortion and point spread function of the lens. In this report, the relationship is made clear by using aberration theory. With some designed examples it is shown that f-8 lens is suitable for scanning purpose, and that the lens makes us highly effective use of laser beam energy by reducing the deformation of point spread function with respect to the deflection angle of beam. As the example of application, the optical elements for semi-conductor laser scanning system are presented.