Optical unit

Abstract

Abstract PURPOSE:To preclude dew condensation due to a temperature difference from atmospheric temperature by constituting an optical unit by putting optical elements constituting the optical system of a light beam scanning device in a housing, and providing the optical unit with a means which substitutes the air in the housing with dry air at all times. CONSTITUTION:The dry air is sent into the housing 12 which contains the optical elements constituting the optical system of the light beam scanning device. Therefore, the housing 12 is filled with the dry air at all times after the light beam scanning device is installed. Consequently, no dew is formed on the optical elements in the optical unit even if the atmospheric temperature varies while the light beam scanning device is in scanning operation or not in the scanning operation.

Inventors

• 👤 Ichiro Miyagawa

Bibliographic Details