Alkylesters of fluorescein dyes were prepared to investigate the ability of spectral sensitization and the adsorption state of them on zinc oxide grains in electrophotographic layers.
The esters were as effective in the sensitization as the non-esterified dyes were, and chemical interactions were observed between the esters and zinc oxide as well as in the case of the non-esters. For, infrared spectra of the esters adsorbed on zinc oxide indicated the ionization of the hydroxyl group of xanthene nucleus, and a considerable amount of zinc ion was detected by atomic absorption spectrometry in the water extract from the. zinc oxide adsorbing the ester. These experimental facts suggested that the esters of fluorescein dyes were chemisorbed to zinc oxide at the hydroxyl group to form zinc salt.
The observations reported here and in the preceding paper can be combined to formulate the adsorption state of fluorescein dyes as that they are chemisorbe.d to zinc oxide by the force of ionic bonds both at the ionized carboxyl and hydroxyl groups.
One of the reasons of the usefulness of fluorescein as a spectral sensitizer for the zinc oxide electrophotography can be considered the presence of such “reactive” functional groups in the dye.

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In this recording method, ripple deformttion patterns are formed on a surface of thermoplastics by electrstatic force of charges transfered to the surface from a photconductive layer through a small air gap.
The theoretical and experimental investigation of this recording method were done. The results are as follows:
(1) For obtaining good quality of images, the biasing voltage for transfer of electristatic images is required more than two times of a latent voltage.
(2) The deeper deformation is obtained by the higher biasing voltage.
(3) The maximum resolution of the recording images is about 70 dots/mm and the contrast is about 10 : 1 when amorphous selenium and gum-resin-wax blend type material are used as the photconductor and the thermoplastics respectively.
(4) A suitable deformation depth for odtaining high light illumination is about 700 nm. Moreover, experimental results of TV image recording are discussed.

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