A MECHANISM FOR RESOLUTION DECREASE IN ORGANIC PHOTOCONDUCTORS

We have studied the mechanism for resolution decrease in organic photo conductors (OPCs). Although exposure to ozone of the OPCs caused hardl y any resolution decrease, a repetition of the charge and light exposu re cycle caused a significant resolution decrease of the OPCs with p-( diethylamino)benzaldehyde diphenylhydrazone (DEH)/polycarbonate (PC) a s their charge transport layer (CTL). After repetition of the charge a nd light exposure cycle, DEH cation radicals and nitrate ions were det ected in OPCs with DEH/PC by using attenuated total reflection UV/visi ble spectroscopy and ion chromatography, respectively. Moreover, the O PCs in which larger amounts of charge transport material (CTM) cation radicals and nitrate ions were detected showed the lowest resolution a mong various CTM/polymer systems. We therefore concluded that the domi nant cause of the resolution decrease was a decrease in surface resist ivity of the OPC, which seemed to be induced by CTM cation radicals an d nitrate ions accumulating near the OPC surface.