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AssigneeRicoh Company, Ltd.
InventorsArthur C. Lutus, Victor B. van Blerk
Estimating the term…
This apparatus relates particularly to apparatus and method for conditioning and pre-fatiguing a photoconductive drum in an electrophotographic copying apparatus. In a preferred embodiment, a two color LED is located adjacent the photoconductive surface. The color of the emissions from these two-color LED's is controlled through the polarity of the voltage applied to the terminals; that is, reversal of the polarity of the voltage applied reverses the color displayed. Therefore, in a preferred embodiment of the present invention, means are provided for supplying an AC driving current to the LED which would inherently result in a synchronous high speed flashing of the red/green light. By combining this AC source with a controllable DC bias, it is possible to provide a drum discharge and preconditioning light which is an all red light; an all green light; or which has controllable percentages of red and green in each duty cycle. In an optimum conditioning cycle, when the machine is first turned on a maximum of two cycles of all red light are utilized to build in fatigue; it is thereafter desirable during extended use of the machine to use only green, which will reduce the light fatigue effect on the photoconductive surface. By an appropriate timing circuit, a controllable shift from all red at the beginning of use of the machine through a combined duty cycle combining both red and green to an all green light can be accomplished.
Conditioning apparatus for establishing or removing background charge levels on a photoconductive recording surface in preparing said surface for reuse in an electrophotographic copying system, comprising
In an automatic electrophotographic copying machine in which photoconductive drum surface is moved past a series of stations including a charging station at which at least a portion of the surface is given a uniform electrostatic charge and an exposure station in which the charged surface portion is selectively discharged to represent a latent image in shades of white through black, an improvement for preconditioning the drum surface to provide consistent contrast in copies made by said copying machine, comprising
A method of conditioning the surface of a photoconductive drum in an electrophotographic copying system wherein a single source of red and green light comprising a red/green LED is positioned adjacent said photoconductive drum and responds to signals of a first polarity to emit red light and signals of a second polarity to emit green light, and comprising the steps of
Dependencies are inferred from the claim text.