Electrophotographic photoreceptor systems

Most practical polymer-based electrophotographic photoreceptor systems now in use are in fact solid solutions of an active species in a binder host polymer 11). This system concept embodies the notion of full chemical control of the transport process. Thus, the concentration of dopant molecules directly controls the drift mobility, which is in turn controlled by the overlap of wave functions between active sites. The host polymer binder is then specialized for its mechanical and adhesive properties. Understanding the key features of small-molecule transport provides guidelines for the optimization of injected-carrier range. The key point is to understand how chemically induced traps arise in such systems and how molecularly doped materials containing various contaminants in substantial quantities can still efficiently transport charge. (Even part-per-million concentrations of con-... 

Well over 100 patents have been issued for a variety of practical applications of calixarene-based molecules. Many of these, not surprisingly, involve the chemistry that is discussed in this book, especially the use of calixarenes in systems in which selective ion complexation plays the central role. A number, however, deal with quite different sorts of applications including, inter alia, the use of calixarenes as adhesion promoters, electrophotographic photoreceptors, ... 

Organic electrophotographic photoreceptors are also widely used in laser printers [13,14]. The principal of these printers is almost the same as in a photocopier except the direct generation of the image by a laser instead of the optical system in a copier. Photoreceptors of the laser printers have to absorb in the near infrared range of spectrum. The third area in which photoconductive polymers or polymer composites are applied are electrophotographic printing plates. 

The electrophotographic system (102,103) involves two key physicochemical elements a photoreceptor and a toner. The minimum requirements of the process are (/) to charge a photoconductive photoreceptor uniformly (2) to illuminate selectively the photoreceptor to form a latent electrostatic image and (J) to develop the image by applying charged toner. These steps are illustrated in Figure 17. 

The electrophotographic method requires a process of forming an electrostatic latent image on a photoreceptor drum by charging and light exposure. Therefore, the system becomes complicated, resulting in increased costs of production (21). 

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