Influence of Space Charges in Carrier Generation Layer on Electrophotographic Characteristics of Layered Photoreceptors (II)
1991 Volume 30 Issue 4 Pages 418-425
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1991 Volume 30 Issue 4 Pages 418-425
In negatively charged multi-layerd photoreceptors, electrophotographic properties, particularly the corona charge acceptance were investigated, from the view point of space charge effect accumulated in the carrier generation layer (CGL). Thickness and other parameters of layer in direct contact with the substrate electrode influenced significantly the charge acceptance. The undercoat layer (UCL) inserted between the substrate electrode and CGL affected electrophotographic propaties in a complicated way. The charge acceptance decreased linearly with the thickness of CGL, suggesting that the charge acceptance was controlled by the hole injection rate from the substrate, which was detemined by the local electric field at the very neighborhood of the electrode. Based on this concept, the space charge density built up in CGL (H2&mdot;Pc) during corona-charging was estimated to be about 6×1016 cm-3.
The UCL was found to be able to modify the amount of space charges in CGL, and consequently to improve the photosensitivity in some caces.
By giving an ability of electron transport to the CGL materia1, the fatigue due to the electrostatic stress corresponding to charging-photodischarging cycles was improved.This fact was interpreted based on an assumption that removal of negative space charges kept the local electric field in CGL constant, even during the illumination.
