Electrofax were made from ZnO and Xerox were Se, but there is something photosensitive electro graphic material except ZnO and Se. This paper reports some properties of evaporated ZnS thin films. ZnS electrophotosensitive plates have transparent properties with visible region and sensitive below 450 mμ.

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Some studies were made on the mechanisms of the development of “Electrofax” paper with colloidal dispersions in an insulating liquid. The ammount of charge and ζ-potential of the phthalocyanine blue particles in the dispersion were estimated by an electrophoretic method, and the maximum theoretical limit of pigment deposition on the “Electrofax” layer having known electrostatic charge was determined.
The rate of development together with the rate of surface potential decay in the liquid developer is discussed on the experimental basis, in relation to edge effects. Useful methods for compensating edge effects were shown.
Resolving power of 100 lines/mm-140 lines/mm was obtained in the contact prints using Dr. Koana's specially made resolution test plates.
And a characteristic edge effect on the reversal white image of thin line objects is also discussed.

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The initial surface potential just after the charging and the potential decrease during the time in the darkness are generally measured in order to know the characteristics of Electrofax papers. But the image quality of the Electrofax papers depends also on the process of charging up the papers. Therefore authors studied in this report the influences of the charging process on the image quality using various kinds of Electrofax papers. A turn table a part of which carries zinc oxide resin system submits to the high voltage charging device then the potential of the part is measured by the electrostatic electrometer during the elapse of time. Relating to the charging process, we have observed too that the conditions of supporting base paper and the sensitive layers have the influences on the image quality. we found that there are two type of Electrofax paper concerning the charging speed. One of them gets quickly the saturation potential while the other gets it slowly.
From the results of experiments, we would like to conclude that to offer the best image quality suitable conditions of charging must be chosen according to the qualities of papers and sensitive layers.

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In this report the authors describe the investigatreory sults on the response characteristics of electrometers for electrophotography.
The test was carried out measuring rectangular wave voltages, and electrophotographic paper potentials, showing that the error due to delayed response cannot be neglected for the rotating vane type electrometer under some conditions.
Turthermore the photo-current on a light sensitive layer was measured approximately by differentiating the output of the standard electrometer

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This paper deals with some problems on the industrial and medical use of Xeroradiorgraphy. At present Xeroradiography is not in practical use yet because the image quality and sensitivity for X-ray radiation are not so good as the X-ray films. Then, we have made some study on the developing method or the making a selenic layer on the aluminium base plate, and found out the new developing method in which smoke is made with an electrical fan.
In this new developing method as well as in the cascade method, toners and glass carriers are employed. This method produces the image better than the cascade method.
The cause of residual image has been studied, and it has been found that the fatigue of the photo conductive plate by radiation brings out the residual image. Our analysis indicates that the fatigued selenic plate shows lower decay curve on x-ray radiation and lower surface potential under the same charging condition.
In addition, some problems of reversed image in Xeroradiography is discussed, and the new reversed paper has been manufactured.

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