IRD PATCH GENERATION
Original Publication Date: 1981-Oct-31
Included in the Prior Art Database: 2004-Apr-02
Xerox Disclosure Journal
In the control of the development system of a xerographic copier or copier/dup-licator, it is known to expose a test area of the charged photoreceptor to a controlled light source and, after development, measure the reflection density of the test area. In such control systems, it is necessary to provide a test exposure which is both uniform and repeatable. An optical densitometer test patch exposure device is shown in the figure. It consists of an array of light emitting diodes 1 optically coupled to an acrylic light bar 2 which is mounted above the surface of a photoreceptor 3. When test exposure is required, the LED'S are energized simultaneously, producing a well defined and uniformly exposed text patch on the photoreceptor immediately below the light bar.