Organized frost: a modulated noise-carrier electrophotographic system.
The theoretical formulation of a modulated noise-carrier electrophotographic process based upon thermoplastic xerography is described. The physical device used in this process is a thermoplastic-overcoated photoconductor. The surface potential of the thermoplastic is modulated by an input exposure. After exposure, the thermoplastic is allowed to deform, i.e., to develop. Assuming that the surface deformation process can be described by a linear hydrodynamic theory, a model for the random surface deformations, commonly referred to as frost, is formulated. This model for frost is based on the theory of noise processes and considers the developed surface deformations to be a gaussian random process derivable from a set of initial infinitesimal surface perturbations. In particular the case is considered where the initial perturbations are such that the deformation process is essentially one dimensional. It is also assumed that the power spectrum of the perturbations is narrow band and centered well above the power spectrum of the two-dimensional, lens-limited input exposure scene. This can be called the organized frost case, and the output images of such a modulated noise-carrier electrophotograph when projected by a central dark-ground system is discussed. Measures of the image background (broad area) and sinusoidal modulation detectability are developed in terms of the physical properties of the thermoplastic, the voltage across it, and the development time.
Heurtley
J C
JC