Latent Charge Visualization Technique
Original Publication Date: 1987-Jan-01
Included in the Prior Art Database: 2005-Jan-31
In the electrophotographic printing process, the print quality depends on the uniformity of the latent image which relies on the charge distribution on the photoconductor drum (PC). Hence, it is essential to sense the PC's electrical defects, which are manifested as missing pixels in copy mode and spots in print mode. Optical detection of photoconductor defects correlates poorly with electrical defects, so direct detection of the latent charge is necessary. Fig. 1 illustrates a PC inspection system using dynamic scattering or pleochroic liquid crystal flat panel. The panel is flood illuminated by a light source emitting at the wavelength where the PC is not sensitive.