Latent image dispersity

Sulfur sensitization does not change the number of latent image centers formed per grain for low irradiance of the mono-disperse fine-grain emulsions. Sulfur sensitivity centers cannot be deep enough to affect the chance establishment of a single stable latent subimage center. In coarse, polydisperse... 

The final step in the development process involves the transfer of the toner particles from the carrier beads to the photoreceptor surface. The forces that bind the toner to the beads are electrostatic and van der Waals dispersion forces. Development thus requires that the forces due to the fields associated with the latent image exceed the forces that holds the toner to the carrier. For a discussion of processes by which toner particles are transferred from carrier beads to photoreceptor surfaces, see Schein (1975), Hays (1977, 1978), and Schein and Fowler (1985). For a discussion of the roles of van der Waals and electrostatic forces, see Gady et al. (1996). 

The description of a colloid should include particle size, mobility, charge and their distributions, charge/mass ratio, electrical conductivity of the media, concentration and mobility of ionic species, the extent of a double layer, particle-particle and particle-substrate interaction forces and complete interfacial analysis. The application of classical characterization methods to nonaqueous colloids is limited and, for this reason, the techniques best suited to these systems will be reviewed. Characteristic results obtained with nonaqueous dispersions will be summarized. Physical aspects, such as space charge effects and electrohydrodynamics, will receive special attention while the relationships between chemical and physical properties will not be addressed. An application of nonaqueous colloids, the electrophoretic development of latent images, will also be discussed. 

The beneficial effects of sulfur + gold sensitisation can be best understood in the context of the loss processes which exist in unsensitised material. The two most important loss processes are (a) recombination and (b) image dispersity. The recombination of the primary photoproducts, electrons and positive holes, which competes with the formation of latent image Ag clusters, is most likely to occur at either very high or very low light intensities. At high intensities, the high concentration of holes and electrons within a crystal enhances the probability of second order encounters. At low intensities, the electrons will spend more of their time in... 

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