The presence of adsorbed oxygen decreases the electronic conductivity of zinc oxide powder.It is shown theoretically how the conductivity is affected by temperature and oxygen pressure.
There are two types of chemically adsorbed oxygen, one occurring at room temperature, the other at higher temperatures.The experimental results of the thermodesorption show that the activation energy for desorption of the lower temperature states and of the higher temperature states is 1.3 eV and 1.8 eV, respectively. On the other hand, the rate of desorption of oxygen was obtained as a function of temperature from the measurements of the conductivity and the resulting data yield an activation energy of 1.O to 11 eV.
It is confirmed that oxygen desorbs from zinc oxide powder by ultraviolet irradiation.
An anomalous behavior of the electronic conductivity was observed below room temperatures. It is suggested that this unusual change of the conductivity is due to water vapor adsorbed on the surface of zinc oxide.

抄録全体を表示

In the previous paper the authors described the results about the antistatic treatments of cellulose diacetate (CDA) to obtain desirable base fims for the electrophotographic transparencies.The present paper reports about the reducing of surface resistivity of CDA by laminating cuprous iodide (CuI) transparent layer.The preparing method of CuI thin layer is the same as that of Lyon.
Some aspects obtained from this study are as follows: (1) The preferable range of Cu evaporation amount is found to be from 45 to 60% in white light transmittance. (2) After Cu evaporation, the metallized film must be iodized as soon as possible. (3) Iodization temperature and atmosphere must be as lower as possible.The dense iodine vapour gives creamy Cul layer or contaminates the film by deposition of free iodine. (4) There is a region in which a surface resistivity of Cu Iayer is higher than that of its iodized state. (5) From the electrophotographic measurements, CuI layer serves as an ideal conductive layer like a metal plate.

抄録全体を表示

For obtaining high photosensitive and uniform layers, a method of lntroduction of copper impurity to CdS evaporated film was studied. One shot process was developed, that is, mixture of CdS powder, CuCl₂ and additive flux of CdCl₂ was evaporated at a heat from a Mo boat on a glass substrate at room temperature. Thereafter, the film was baked in the air. The film repoducibly produced, had high dark resistivity and high photosensitivity.
First, the effect of evaporating and baking conditions was studied and second, the effect of impurity and flux was studied, on the various properties; excitation spectra, photosensitivity, dark current and transient behaviours. Microscopic observation and x-ray analysis were also done.
As evaporant contains materials with different vapour pressure, composition of evaporating materials varies with proceeding of evaporation. The effect was studied, too. The results will present valuable data to obtain high photosenitive evaporated CdS films.

抄録全体を表示

Photocurrent in visible region and ESR absorption of Li and Ag-doped ZnO were measured at 20℃ under oxygen pressure≃10^-2 mmHg to interprete lthe mechanism of photoconduction of ZnO.
The results are as follows:
(1) An adsorbed oxygen, O^- (g=2.003∼2.OO4) and an interstitial zinc ion, Zn^- detected by ESR method, contribute to the photoconduction of ZnO in visible region at the above“conditions.
(2) The proposed processes of photoconduction of ZnO are illustrated by the following equations:

抄録全体を表示

In dry developing process of electrophotography, triboelectric property of developer affects much the image quality obtained. For this reason, it is necessary to measure the triboelectric property of the developer for getting a good developer.
The purpose of this paper is to report a method of measurment on triboelelectric property of the powder developer composed of carrier and toner.
The measurement took place as follows. The surface of paper placed on metal plate was brushed with developer as a megnetic brush while a bias voltage was applied between the metal plate and developer. By this process, toner which is adhering on the surface of carrier was attracted by the potential of the plate and transfered to the surface of paper. From the relation between amount of toner and applied voltage, the triboelectric property of developer was deduced. The convex curve shows that the distribution of charge in toner particles is broad, on the contrary the concave one means that the distribution is narrow.
The effect of humidity to the triboelectric property of developer was also observed about carriers of three types.
As good reproducibility was obtained from this measurement, this method can be applied to the inspection of toner and carrier.
Using the results obtained, the explanation of some problems of electrophotography was tried.

抄録全体を表示