Mechanisms of toner scattering from a developer unit for the two-components developer consisting of toner and insulative carrier have been examined by varying the covering ratio(θ)of a carrier surface with toners, the toner surface-area median size(d₅₀), and the carrier-area median size(D₅₀). It has been found that the toner-weight scattered down on the horizontal unit area in front of the developer unit, normalized by n particles of toners which were randomly distributed on the surface of one carrier, charged by triboelectrification, and adhered to the carrier (Wt/n), increases exponentially with increasing the covering ratio (θ), or surface-area ratio of n toners to a carier (ns_t/s_c), independent of the toner size and the carrier size. This exponential increase of the toner scattering, (W_t/n), is accompanied with a decrease of the product of toner surface-charge density (q/s_t) and contact electrostatic field (E_k) between the toner and the carrier, namely, with a decrease of Coulomb's force per unit area (qE_k/s_t) at the contact part of the toner and the carrier.

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Several studies have been done for a new thermal melt transfer printing method, using focused diode laser light instead of thermal head heating for wax type ink ribbons. Accordingly the Laser Induced Melt Transfer (LIMT) printing system has been developed specially for this application. This LIMT printing system can control the laser light turn on period for every picture cell at any position of image. The digital test images were printed as a gathering of individual picture cell by raster scan operation of this system.
As a result of this experiment, high resolution mono color binary image up to 1900 dpi was obtained. This is difficult to print by current thermal head. The color multilevel gray scale image was also obtained as an over print of three colors (Y, M, C) using the dither method. It is possible to change the printed picture cell size by pulse width modulating of the laser light turn on period. And, the observed printed picture cell size increased with increasing length of the laser light turn on period. Then the full color reproduced image from input picture cell data to output gray scale based on this variable picture cell size was obtained.
This report outlines the basic characteristics behind this LIMT printing method of image reproduction and the related system.

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A contact-type monocomponent non-magnetic development using a conductive and elastic development roller is effective for the improvement of image quality of photoprinters because the development electrode is held extremely close to the latent image. Recently, development systems which employ semi-conductive or dielectric rollers are also studied. The authors propose a unified theory which describes the physics of these three kinds of contact development systems. Development currents are taken into consideration in the analyses, and equations which show the relation between the roller resistance and the development characteristics are derived. The results of analyses and experiments show that a conductive roller, having a low friction-coefficient conductive surface layer and a resistivity of less than 1×10⁴ Ωm², to which a development bias voltage is applied through a protective resistor of l to 10 MΩ, is most advantageous.

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This paper describes a recording process that exposes and develops at the same time, and the conditions involved.
The magnetic bursh development unit and the image exposure system are on opposite sides of a photoconductor having a transparent base. A toner image is poduced on the photoconductor in two steps: First, the image is exposed from the back of the photoconductor when the toner is uniformly developed via a stripe electrode on the development unit. Second, unexposed is electrostatically collected in a developer pool near the stripe electrode by a scavenging voltage.
We defined the printing conditions and manufactured a prototype printer. The printer contains a development unit having a stripe electrode, LED array optic, transfer roller, an erase lamp, and a fuser unit, on a recording medium consisting of an organic photoconductive film belt. The developer is consisting of magnetic insulating toner and carrier with magnetic conductive smaller particles. The printer produced a satisfactory plain-paper printout with an optical density of 1.0.
Since this recording process does not use corona charging which is essential for the conventional electrophotographic process, a simple recording system is possible that does not generate ozone. Furthermore, the toner is reusable in this system. There is no waste, thus ensuring economical operation.

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This paper describes the mechanism6f corona separation on electrophotography in terms of energy-analysis. That energy mainly indicates electrostatic energy which is given by electrostatic force operating between drum and transfer material, and elastic energy which is stored up in transfer material by stiffness when it sticks onto drum. Therefore we have tried to analyse that mechanism by means of interaction between these energies, and clarified some of following characteristics regarding separation efficiency.
1) There is no difference of separation efficiency between normal development system and reversal development system.
2) As regards adjustable range of discharger condition, the transfer material with large separation efficiency generally includes one with small one, so that we can decide unique discharger condition to all transfer materials.
3) Separation efficiency is affected by not only stiffness but dielectric constant of transfer material.
4)All transfer materials have same slope of separation efficiency as function of surface potential on photoconductor.
Therefore in order to inspect these characteristics, we had an experiment on separation of various transfer materials and we could get good results roughly.

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Living organisms possess exrtemely sensitive sensors by which the organs are capable of probing their various environmental signals such as chemicals heat, gravitational force and photon. In this chapter, we will discuss photoreception and phototransduction of animal photoreceptor cells. Primary process of photoreception and color regulation of visual pigments will explained by molecular bases.

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