Abstract: An intensity correction circuit adjusts the intensity of the pixel data which modulates the light beam of a raster output scanner to compensate for facet to facet reflectivity intensity differences of the rotating polygon mirror used to scan the modulated light beam on a photosensitive medium.

Abstract: A raster output scanner is disclosed which utilizes a collimator assembly which can be replaced at the field. The collimator assembly is mounted on a raster output housing. Both the raster output housing and the collimator assembly have securing means to secure the collimator assembly to the raster output scanner housing. The raster output scanner housing and the collimator assembly are designed to provide automatic adjustment for the light beam exiting from the collimator assembly with the optical path within the ROS housing once the collimator assembly is secured to the raster output scanner housing.

Abstract: A raster output scanner is disclosed which utilizes a replaceable laser diode and a replaceable microchip which contains characteristics information of the laser diode in use by the raster output scanner. Once, the laser diode is replaced, the microchip has to be also replaced by a microchip which contains the characteristics information of the new laser diode.

Abstract: A computer controller for a raster output scanner. The software consists of an operating system and application programs. Each application program acts as a servo loop and controls such operating variables as the laser diode input power, output light intensity and temperature, and polygon speed. The operating system receives the current values of these variables, compares them against ranges limits and will inform the operator of malfunctions or needed maintenance in addition to managing the more typical computer functions such as driving peripherals and managing memory. The entire software system is generalized to the point where it can calibrate and maintain any ROS, and therefore need not be redesigned for different ROS products. In addition, when hardware parts are replaced, the operating system can change the operating ranges instead of replacing the programs.