Minolta Camera Kabushiki Kaisha

Hideyuki Kurahashi

Haruhiro Hyodo

A zoom lens system, for use in a copying apparatus, is provided with, from the object side, a first lens unit of a negative power including a negative lens element, a second lens unit of a positive power including a positive lens element and a negative meniscus lens element concave to the image side, an aperture stop, a third lens unit arranged symmetrically with the second lens unit with respect to the aperture stop, and a fourth lens unit arranged symmetrically with the first lens unit with respect to the aperture stop. The second lens unit and the fourth lens unit are moved in a same direction in association with each other so that the total length of the zoom lens system is minimum at unity magnification. The aperture stop moves so that the symmetry of the entire zoom lens system is maintained. An object-image distance is maintained constant by moving the entire zoom lens system.

Zoom lens system for use in copying apparatus

A device for amending a non-uniform illuminance of an image projected on an photoconductive drum, the device comprising a first shielding member provided between a glass document table and a projecting lens for shielding a portion of a light beam from a peripheral portion of a document image partially in a reduction mode, and a second shielding member provided between the projecting lens and the photoconductive drum for shielding another portion of the light beam from a central portion of the document image partially in an enlargement mode.

Growing community of inventors

Osaka, Japan

Hideyuki Kurahashi