The behavior of phosphors under low voltage (less than 100V) cathode ray excitation is investigated. A phosphor coated on an anode plate is excited by low voltage cathode rays from two line cathodes. Brightness increases as the distance between the anode and the cathodes decreases. Most phosphors used here show high brightness when mixed with conductive materials such as In2O3 or SnO2 . The smaller diameter of In2O3 mixed with Y2O2S:normalEu , the lower added amount of In2O3 necessary for maximum brightness. normalZnS:normalCu,normalAl coated with SnO2 shows maximum brightness when the added amount of SnCl4 is 100 w/o and the sample is fired at 700°C. false(Lax,Lu1−xfalse)InO3:normalEu shows spectrum variations according to the change of x and Eu concentration. The peak wavelength of LaInO3:normalEu changes to longer wavelength when the phosphor is sulfurized into LaInO2S:normalEu , which is a similar phenomenon to that shown by Y2O3:normalEu and sulfurized Y2O2S:normalEu under conventional high voltage cathode ray excitation.

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Electrophotographic behaviour of a plate having two-layer structure consisting of a CdS-resin and an insulating layers is investigated. Three processes are used in which positive corona discharge is commonly applied at Step 1. Process 1 and Process 2 are different in Step 2, as negative corona discharge and ac corona discharge are used respectively with simultaneous exposure. Process 1 is better to obtain high contrast voltage than Process 2, even if the same plate is used. This is ascribed to the fact that Process 1 can widen the surface potential of the plate over its saturation potential. Process 2 does not give the contrast voltage difference between two plates with different properties, although Process 1 clearly distinguishes these plates from each another. The relationship between light part and dark part of surface potentials at Step 2 in Process 1 is opposite to that in Process 2, although the relationship is the same at Step 3. When plates are not charged to show their saturation (acceptance) potentials at Step 1, those behave differently, depending on whether the plates are charged with simultaneous light image projection soon after Step 1 (Process 1) or after uniform illumination following Step 1 (Process 3). Properties of photoconductors are investigated and the behaviour difference between plates is analyzed.