We made the diameter smaller (φ10) and the magnetizing stronger on a magnetic roller for development.
It was achieved by the most suitable magnetic pattern which was sougth by analyzing the magnetic field of magnetic roller.
A strong magnetizing is achieved by magnetizing efficiently the main pole of a small development roller.
Taking the main pole (the North pole) as a center, the former magnetic model was alternated between the South pole and the North pole.
Therefore the magnetization of the former model is not strong because of dispersing a passing magnetic flux of the main pole of a development.
We collected some same magnetic fluxes of the South pole in the new magnetic model, which caused the fluxes to concentrate on the north pole of a development.
As a result, a magnetic force of this roller was able to become strong. And besides we got a, high quality of copy by putting this magnetic roller in a developer unit of low speed copying machine (MINOLTA EP423Z).
We found the possibility of making a compacted developing device by using this magnetic roller.

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A novel electrophotography “One Drum Color Superimposing Process” has been developed, in which process each color toner image is directly superimposed onto the photoconductor followed by transferring to a plain paper at once. To prevent color cross-contamination during color superposition, a non-contact and mono-component development method is employed in each of three color development units. Insulative toner is triboelectrically charged by a conductive fur brush provided in the development unit, and is made to adhere to a developing roller electrostatically. An elastic rubber blade is provided to form uniform toner flayers of approximately 30 μm thick. The developing roller is set to face the photoconductor keeping with a gap of 150 μm. By applying a bias potential of 800 V, the toner from the developing roller flies for developing latent images. The developed color development method is employed in the “Panasonic FP-C1” digital color copier.

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In the electrophotography “One Drum Color Superimposing Process”, a toner flying development method is employed for color superposition on a photoconductor. The resolving power of this development method is analized relating to various factors such as developing gaps, toner charge, thinckness of toner layers, etc. In addition, a relation between exposure and development is studied. Obtained results are as follows:
(1) Toner with low charge can fly to a latent image, but toner with high charge cannot fly from the developing roller.
(2) Exceedingly thick toner layer on a developing roller causes background, 6ven if there is no reversely charged toner.
(3) In the comparison between 240 dpi and 400 dpi, not only the potential width of 400 dpi becomes narrower, but also its potential well becomes shallower.
(4) Adjacent lines of 400 dpi give an influence to each other at the time of development, even if each exposed line is independent. Potential of a peak between exposed lines drops to about 500 V, which level is easy to be developed when high bias voltage is applied.
From these analyses, optimal conditions of toner flying development and exposure are determined. These resultant specifications are adapted to the “Panasonic FP-C1” digital color copier.

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We have studied gap state profiles and light-induced fatigue in amorphous selenium (a-Se) by means of xerographic discharge measurements. Prolonged illumination increases the density of charged defects in a-Se. Nature of charged defects created by light exposure is similar to that of native structural defects D⁺ and D^- . The formation of charged defects is enhanced by light illumination of photon energy equal to the band gap of a-Se. In addition, the creation efficiency of photo-induced charged defects under an applied electric field is small compared with that under zero field. These experimental results imply that the geminate recombination of electron-hole pairs plays an important role in the creation process of charged defects, D⁺ and D^- in a-Se.

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It has been found that the photosensitivity of amorphous silicon (a-Si) photoreceptor fabricated by glow-discharge decomposition of (SiH₄-B_2H6-Ar) has specific relation to the peak-to-peak value of R_f Voltage (V_p-p) and the DC bias voltage (V_DC) on the R_f powered-electrode. Namely, the lower the V_p-p value is depressed, the higher the photosensitivity is improved. Dependences of the V_p-p value on deposition parameters of a-Si:H (B) film such as gas pressure (P) , distance between R_f powered-electrode and aluminum substrate (l), R_f electric power (R_f), and dilution ratio of SiH₄ to Ar (F_SiH4/F_Ar) seem to indicate correlation of V_p-p with electron energy and electron density in the plasma.
Furthermore, the V_p-p and V_DC Values have been measured in the plasmas of He, Ne (rare-gases with no Ramsauer effect), Ar, Kr, Xe (rare-gases with Ramsauer effect), and H₂, N₂, CH₄, SiH₄ (molecular-gases). Interesting behaviors in V_p-p and V_DC Seem to have correlation with collision cross sections (σ) of electrons (with the energy of 2-10 eV) in these gases.

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