Kazuyoshi Tateishi

Corona Current Control by Mesh Grid

Corona charging is widely used for charging dielectric surfaces. It is desirable to attain precise and uniform surface voltage in its application. A corona charging method using a mesh grid is described. It is found that the corona current control characteristics by mesh grid can be expressed by a nondimensional parameter¿the corona current transmission rate. This parameter is obtained experimentally. The method of parameter application in dielectric surface charging is expressed by a differential equation. This technique is applied to charging amorphous selenium xerographic plates and to neutralizing the charges on a dielectric surface. It is found that the surface voltage obtained by charging with a mesh grid is far more uniform than that obtained by charging without a mesh grid.

Photoconductivity Mechanism in Beta-Carotene Glass

Photoconductivity spectra are measured on beta-carotene glass consisting of a mixture of isomers using a sandwich type cell and a surface type cell. In the sandwich cell, the different spectra are obtained by the polarity of the illuminating electrode. When the illuminating electrode is positive, it is concluded that the origin of the photoconductivity spectra in the wavelength below 400 nm is hole photoinjection from the electrode. The photoconductivity band is found in the wavelength 600∼800 nm, and the origin of the band is suggested to be intrinsic.

Electrophotographic Printer Using LED Array

An electrophotographic printer using a light-emitting diode (LED) array light-scanning technology has been developed. This printer has the following features 1) compactness (40-cm width x 50- cm depth x 25-cm height, 2) high printing speed (3 s/letter size), and 3) high resolution (10 lines/mm). To realize this printer, two key elements have been developed. One is a large high-density LED array, and the other is a three-layered Se-SeTe-Se photoreceptor which is highly sensitive in the long wavelength region. The required conditions for the two key elements and the methods used to obtain the characteristics of the elements are discussed. The other technologies used in the printer are also explained.

Charge Carrier Mobility Measurements in Beta-Carotene Glass by Transient Photoconductivity

Transport of holes through beta-carotene glass was studied using a transient photoconductivity technique. The mobility is measured to be 1.5×10 -3 cm 2 /V sec at 21°C and 10 4 V/cm. The motion of carriers can be represented by transit time T r , which means the time necessary for a charge carrier to travel from the front electrode to the counter-electrode of the sample. The inverse transit time ( T r ) -1 is found to vary with temperature T in the form of exp (- e 0 / k T ), with e 0 =0.22 eV, and to vary with electric field E in the form of exp (α c E 1/2 ) with α e =2×10 -3 (m/V) 1/2 . Dielectric constant e of beta-carotene glass was measured to be α=1×10 -10 F/m at 1 KHz. Using the Poole-Frenkel theory, the coefficient of E 1/2 in exp (α t E 1/2 ) is estimated to be α t =1×10 -3 (m/V) 1/2 . The observed α e agrees approximately with the value of estimated α t . Therefore, it is concluded that the transport of charge carrier is mainly controlled by the Poole-Frenkel effect.