| 摘要 |
<p>A multi-layered electrophotographic element providing significantly improved properties, and especially so for use as a "permanent" master in transfer photocopying, comprises a conductive support carrying a photoconductive charge generating layer and on top of the photoconductive layer a charge transporting layer containing homogeneously distributed in an insulating binder a charge transporting agent selected from among certain azines which may comprise one or more alkylsubstituents and/or heterocyclic groups with at least one nitrogen atom and/or phenyl or naphthyl groups. The charge transporting layer may also contain to advantage an activator for the charge transporting agent. Particularly effective activators are terephthalal dimalonitrile (TDM) and 1,3,7- trinitro-dibenzothiophene-5,5-dioxide (DBTO). The charge transporting layer preferably is applied to a very thin charge generating layer formed on an endless support,and which contains the charge generating compound in molecularly divided form. Photocopying can be carried out with enhanced permanence of the usefulness of the element by charging the element for each copying operation to not more than about 70% of its maximum chargeable surface voltage.</p> |
