Jeanne E. Kaeding

Photoelectrographic masters containing nonionic acid photogenerators

Photoelectrographic printing is a technology which utilizes photoelectrographic masters and conventional electrophotographic toners for short run printing applications. Masters based on onium salt acid photogeneration have many desirable attributes. One shortcoming, however, is their sensitivity to changes in relative humidity. We have previously reported on a class of polymeric binders which largely overcome this problem. We have now found a class of non-ionic acid photogenerators which further enhance the performance of such masters with respect to changes in relative humidity and which enable the use of a broader spectrum of polymeric binders. We examined representative compounds from several classes of non-ionic acid photogenerators. The best results were obtained with sulfonate esters of N- hydroxyimides. Standard polycarbonate or polyester-based formulations containing these compounds along with a near-UV sensitizer exhibit contrast potentials near 90% of the initial surface potential upon exposure with a 500-W mercury arc lamp. This contrast potential remains nearly constant over the range of 30-70% relative humidity.