Imaging system

#This invention relates in general to xerography and more specifically to a novel photosensitive device.

#Vitreous and amorphous selenium is a photoconductive material which has had wide use as a reusable photoconductor in commercial xerography. However, its spectral response is limited largely to the blue-green portion of the visible spectrum, i.e. below 5200 angstrom units.

#Selenium also exists in a crystalline form known as trigonal or hexagonal selenium. Trigonal selenium is well known in the semiconductor art for use in the manufacture of selenium rectifiers.

#FIG. 1 is a schematic illustration of one of the members of the instant invention which comprises particulate trigonal selenium randomly dispersed in a resinous binder overlying a substrate.

#FIG. 2 is a schematic illustration of one of the members of the instant invention wherein the particulate trigonal selenium is geometrically dispersed within an electrically insulating organic binder. This layer overlies the substrate.

#FIG. 3 is a schematic illustration of one of the members of the instant invention illustrating a composite photoreceptor comprising a charge carrier generation layer overcoated with a charge transport layer. The charge carrier generation layer comprises the selenite and carbonate modified trigonal selenium dispersed in an organic resinous binder as the charge carrier generation layer.

#For a better understanding of the Figures, several terms should be defined. The term "rested dark decay" when used in this application means that it is the amount of voltage drop, i.e. surface potential drop, of a member which has been rested and then charged initially to an initial surface potential, measured in voltage, and then allowed to remain in the dark. The drop in potential is measured 0.06 seconds after charging, 0.22 seconds after charging, and 0.66 seconds after charging. This "rested dark decay" means that the photoreceptor has been rested in the dark for at least 30 minutes prior to testing i.e. cycling in a xerographic mode.

#"Fatigue dark decay" means, for purpose of this application, a drop in surface potential 0.06 seconds after charging, then after 0.22 seconds and then after 0.66 seconds. These measurements are made while the photoreceptor remains in the dark. "Fatigue dark decay" further means that the photoreceptor has been cycled at least one time through a xerographic cycle and then discharged, i.e. erased, and then is tested before the photoreceptor has rested, preferably before 30 minutes has passed after charging the photoreceptor. The process speed of the photoreceptor is 30 inches per second.

#Referring to FIG. 1, reference character 10 designates an imaging member which comprises a supporting substrate 11 having a binder layer 12 thereon. Substrate 11 is preferably comprised of any suitable conductive material. Typical conductors comprise aluminum, steel, nickel, brass or the like. The substrate may be rigid or flexible and of any conventional thickness. Typical substrates include flexible belts of sleeves, sheets, webs, plates, cylinders and drums. The substrate or support may also comprise a composite structure such as a thin conductive coating contained on a paper base; a plastic coated with a thin conductive layer such as aluminum, nickel or copper iodine; or glass coated with a thin conductive coating of chromium or tin oxide.