After a brief introduction of Kondo Theory on the development by high resistance magnetic toners, some experimental results are given on the dependence of development characteristics (e. g., Q-V₀ and M-V₀ curves) upon the difference of development conditions, such as thickness of photoconductor (d), photoconductor to roller spacing (g_P), toner resistance (R_b), intensity of magnetic field (B), kind of latent images and the radius of toner particles (r).
From the analysis of these experimental data, it is proved that a sufficient agreement is obtained between the theoretical and experimental effects of the above development conditions on the numerical values of threshold voltage (V_k), the slopes of Q-V and M-V₀ curves (tan θ₁ and tan θ₂), the charge to mass ratio of toner particles (q/m), the equivalent thickness of toner brush (D_b) and so on.

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The mechanism of image formation in binder type photo-migration imaging film was investigated.
When a photo-migration imaging film having a thin layer comprising Cu phthalocyanine dispersed in a rosin derivative was electrostatically charged, imagewise exposed and processed with a solvent liquid, positive-to-positive imaging resulted in the case of positive surface charging, while negative imaging took place in the case of negative surface charging, with a solarization region occurring for larger exposures.
These experimental results can be explained by considering the following two factors, both caused by light simultaneously:
i) the charge polarity change in individual particles from positive to negative, and
ii) the imagewise distribution of the electric field across the layer.
The rate of polarity change by light proved to be strongly field-depent. In the solarization region, the field substantially collapsed, whereby further exposure promoted the negatively charged particles to return to the thermally equilibrated, positively charged state.

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