Dual layer photoreceptor

Figure 3 Cross section of (a) mono- and (b) dual-layer photoreceptors.

Figure 5 A cross-section schematic of the dual-layer photoreceptor configuration. Transport layer thicknesses are typically 15 to 30 pm. Generation layer thicknesses are usually between 0.5 to 5.0 pm.

Pacansky et al. (1987) described the fabrication of dual-layer photoreceptors by radiation curing. The layers were coated with a polymerizable acrylate monomer or oligomer as the liquid component, then cured by a 175 kV electron beam or ultraviolet exposure. These methods were used for the preparation of generation layers containing bisazo and hydroxysquaraine pigments. 

Figure 5 The field dependencies of the photogeneration efficiencies of single- and dual-layer photoreceptors prepared with AZO-FO. For the dual-layer structures, the transport layer contained a stilbene derivative (MAPS).

Figure 7 The field dependencies of the photogeneration efficiencies of dual-layer photoreceptors containing AZO-TPA. The transport layer contained the triarylamine derivative MAPS at different concentrations.

Umeda et al. (1993) measured photogeneration efficiencies of dual-layer photoreceptors comprised of AZO-TPA generation layers with transport layers... 

Figure 10 The energy scheme of photocarrier generation of a dual-layer photoreceptor.

Figure 11 The photogeneration efficiencies of a series of dual-layer photoreceptors versus the oxidation potential of the donor component of the transport layer. The generation layer contained AZO-TPA. The transport layers contained a series of biphenylamine (DBA) derivatives.

Figure 13 The field dependence of the photogeneration efficiency of a dual-layer photoreceptor, a single-layer photoreceptor, and the photoluminescence quenching of the dual-layer photoreceptor. The generation layer contained AZO-FO. The transport layer contained a stilbene derivative (MAPS).

Figure 14 A schematic of the photogeneration process proposed for dual-layer photoreceptors containing AZO-FO.

Umeda and Yokoyama (1997) measured photogeneration efficiencies of single- and dual-layer photoreceptors prepared with 4,4 -[(9,10-dihydro-9,10-dioxo-2,6-anthracenediyl)bis(azo)]bis[N-(3-bromophenyl)-3-hydroxy-2-naphth-alenecaiboxamide] (ABHN) (Hashimoto, 1985) and 4,4 -[l,4-phenylene-bis (2,l-ethenediyl-4,l-phenyleneazo)]bis[N-(2,4-dimethylphenyl)-3-hydroxy-2-na-phthalenecarboxamide] (PDHN) (Sasaki et al., 1980). For the dual-layer configuration, the transport layer contained MAPS. Single-layer photoreceptors... 

Hirao et al. (1995) measured photogeneration efficiencies of dual-layer photoreceptors prepared with generation layers of C q and C7q. The transport layers contained 22.5% N,N/-diphenyl-N,N,-bis(3-methvlphenyl)-(l,T-bi-phenyl)-4,4 -diamine. TPD. Figure 41 shows the spectral dependencies of the efficiencies computed on an incident photon basis. The efficiencies of C7q were somewhat higher than for C q. 

Figure 5 Bisazo pigments used in dual-layer photoreceptors.

A dual-layer photoreceptor with an uppermost generation layer of X-H2PC dispersed in a TK>2 glass has been described by Takahashi and Yamamoto (1995). 

The effects of the generation-layer fabrication variables on the sensitometry of a dual-layer photoreceptor prepared with bis(4-dimethylaminophenyl) squaraine (X = H in Appendix 2) have been extensively investigated by Law (1987). The charge acceptance, dark discharge, sensitivity, and the residual... 

A squaraine prepared from N-chlorobenzyl-N-methylaniline and squaric acid has found utility as a generation layer in a dual-layer photoreceptor with an inverted structure for positive charging applications (Yamamoto et al 1986). The photoreceptor showed full-process stability. 

Alkyl-substituted nitrated fluorene-9-ones were synthesized with the expectation of improved solubility and lowered toxicity (Loutfy and Ong, 1984 Loutfy et al., 1984 Ong et al., 1985). These showed improved solubility and somewhat improved mobilities compared to TNF. Studies of dual-layer photoreceptors prepared with (4-H-butoxycaibonyl-9-fluorenylidene)malonitrile transport layers have been described by Loutfy et al. (1984) and Murti et al. (1987). Low-field trapping was observed. The mobilities of this molecule in a polyester (PE) have been described by Borsenberger et al. (1990) and Borsenberger and Bassler (1991a). A transport layer with this molecule pendant lias been prepared and used with a TiOPc generation layer (Sim et all., 1996). A very significant residual potential was observed. For reasons that are not well understood, this is a common observation for dual-layer photoreceptors prepared with acceptor doped transport layers. The residual potential usually increases with cycling such that the useful process lifetime is limited. 

Decreased charge acceptance of dual-layer photoreceptors with N,N -dipheny l-N,N -bis(3 -methylphenyl)-( 1,1 -bipheny l)-4,4 -diamine (TPD) containing transport layers after extended corona exposures has been reported by Pai and Yanus (1984). This effect was reduced by the addition of a thin polymer surface layer doped with bis-(2-methyl-4-N,N-diethylaminophenyl)phenyl-methane. Ong et al. (1989) described a similar effect with an inverse dual-layer photoreceptor. In this case, the surface layer contained an electron transport... 

Takenouchi et al. (1988) described a dual-layer photoreceptor in which transport-layer ozonolysis occurred. The transport layer contained substituted p-styryltriphenylamines, Fig. 11, which reacted as shown. Fatigue was manifested as a residual potential that increased with ozone concentration The... 

Environment effects have been described by Law (1987) in studies of a dual-layer photoreceptor with a squaraine-pigment-based generation layer. Seasonal fluctuations in dark decay and charge acceptance were observed and related to humidity. Water adsorption on the pigment particles was suggested as the underlying cause. 

Table 1 The Effects of X Substituents of the Anilide Functionality on the Absorption and Sensitivity of a Series of Dual Layer Photoreceptors Using a Diaminofluorenone bisazo Pigment in the Generation Layer. (After Hashimoto, 1986)...

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