A review of theoretical and experimental articles on the process of formation of latent electrostatic image in electrofax papers is presented.
First, concerning the charging process, Amick's “Volume Charge Capacitor Model” is explained, which, after the author's experiment on the rise characteristics of surface potential for the pre-exposed samples, is modified in such a way that negative O
2- ions invade into the electrofax layer and migrate along the ZnO microcrystal surface toward the base, taking into account the real nature of the porous layer.
Next, light absorption property is illustrated after the author's work on the reflectance measurements for the various layer thickness samples of same composition, deriving theoretical expressions describing light intensity distribution and absorption in the electrofax layer using Kubelka's equation.
And next, analytical considerations are done on the photo-induced discharge process, where mean traverse length of photoelectrons
w is directly related to the decrement of surface potential, and given thoretical expressions with mean range
w and several optical parameters, and charge density distribution is also shown.
Furthermore, several data including
w obtained by the quantum yield measurments for the discharging process are shown with some analytical procedures.
Finaly, concerning the interpretation for the shape of photo-decay curve which is specific for electrofax papers, Levinson's model is presented, followed by author's another explanation based on varying
w, which necessitates a mechanism of increasing of photoelectron life τ throughout the process, and an experimental result supporting author's view is shown.
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