OPTICAL METHOD FOR CREATING A ROS WITH MULTIPLE RESOLUTIONS
Original Publication Date: 1989-Aug-31
Included in the Prior Art Database: 2004-Apr-05
Xerox Disclosure Journal
A Raster Output Scanner (ROS) imaging system can be produced for a printer by combining a Light Emitting Diode (LED) array or a liquid crystal pixel array system and a gradient lens array in close proximity to a photoreceptor in a xerographic engine. The resulting printer is limited in axial output resolution to the spacing in the pixels in the array, typically 200 to 400 spi. Gradient index lens arrays which reduce or enlarge images are known. Combining such lens arrays with a linear pixel array light source will create a ROS which can produce image spots at either a higher resolution (Figure 1) or lower resolution (Figure 2) than the pixel array spacing. It is also possible to use a single reductiodenlargement gradient index lens array for both enlargement and reduction by rotating and translating the array. This mechanism is shown in Figures 3 and 4. With this mechanism included, two resolutions of printing are available with one pixel array. The concept is expandable to four or even more resolutions by adding more lenses.