| 摘要 |
A liquid crystal image bar for an electrophotographic printer is disclosed, having a nematic liquid crystal device with crossed polarizers configured as a single array of dot shutters that are driven by a single frequency voltage source. The image bar produces latent electrostatic image on the printer's photoconductive member one line at a time in response to receipt of digitized data signals. During the operational mode, all of the image bar shutters are energized and, in this electrically driven state, the image bar shutters are non-transmissive. The latent image is produced by selective erasure of precharged background areas on the member. For the erasure to occur, interruption of the driving voltage to selected shutters in response to the data signals cause the selected shutter to become transmissive because the liquid crystal material enters a transient state. The response time for the transmissiveness is about one millisecond. Consecutively erased spots by the same shutter requires the momentary reapplication of the driving voltage. Because the function of the image bar is relatively independent of temperature and gap thickness, it is very cost effective. |
