ELECTROPHOTOGRAPHIC DUAL-LAYERED PHOTORECEPTORS INCORPORATING COPPER PHTHALOCYANINES

Electrophotographic characteristics of negatively charged dual-layered photoreceptors with alpha-, beta-, epsilon-form, and partly nitrated alpha-form copper phthalocyanines for charge generation materials and three charge transport materials have been investigated. Excellent sensitivities of 6.4 erg/cm2 could be measured at 600 nm for the photoreceptor that used partly nitrated copper phthalocyanine. The photoreceptor that used epsilon-copper phthalocyanine exhibited high sensitivity of 15 erg/cm2 in the near-IR region. Hole-carrier injection efficiency from charge generation layer to charge transport layer depended on the ionization potentials and carrier generation ability. On the contrary, the photoinduced discharge curve and a half-decay exposure sensitivity depended on the hole-carrier drift mobility in the charge transport layer, rather than the ionization potential and injection efficiency.