This paper describes accurate numerical analysis results obtained for the ink-jet phenomena using the Finite Element Method, and reports an ink droplet generation method exciting a relatively high order harmonic of pressure vibration in the ink channel makes it possible to eject small ink droplets from a relatively large nozzle. An experimental head using fifth-harmonic excitation, could print 50 μm diameter spots from a 40×70 μm nozzle. A prototye printer could print a full color image at 480 dots/inch resolution.

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The drop generator for the continuous multi-orifice ink jet printing technology is described. The drop generator configuration, the piezoelectric transducer stimulator motion, the acoustic cavity dimensions, and the break off uniformity of the jets are discussed. To obtain the break off uniformity of the jets, the piezoelectric transducer stimulation uniformity and the acoustic cavity dimensions are investigated and the variation of the orifice diameter is improved. The piezoelectric transducer is cut so that it functions like an array of simple length expander resonators. The cavity is designed so that its length is not equal to the integral multiple of λs/2 (λs : acoustic wavelength in ink) and its height is equal to λs/2. Glass fibers, which are used to form the orifices, are sorted by an optical comparator to reduce the variation of the orifice diameter. With this drop generator, we could make the break off uniformity of the jets within λ/2 (λ: drop separation) and T/2 (T : one cycle of the operating frequency).

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This paper describes simulated results of thermal diffusion in Thermal Ink-Transfer printing utilizing three-dimensional finite element method. The change in melted area by adjacent heating element and heat accumulation were calculated. The simulated results were found in good agreement with experimental values. It has been clarified this simulation is useful for determining the printing energy conditions.

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A new type of two-color thermal recording paper which develops black and red images under low temperature is described. The paper consists of only a single thermosensitive layer containing coupling agents, an organic base, a thermosensitizer and two kinds of diazonium salts encapsulated indivisually in microcapsules. Under the heat treatment, the two diazonium salts of A and B react with the coupling agents to develop green and red colors respectively. On the other hand, the former A, is decomposed by exposure to light of a wavelength of 420 nm and on contrary, the latter B, is not decomposed by the same treatment.
This noble thermal paper provides two color images with the following procedure; i) the first thermal processing develops a black image (green+red) prepared by A and B, ii) the exposure to light of a wavelength of 420 nm to decompose the diazonium salt A, iii) the second thermal processing to develop a red image in the non-black area.
This thermal recording paper has advantages of a high thermosensitivity to be suitable for the G3 facsimile equipment and a high resistance to such chemicals as those containing in sign pens, markers and mending tapes.

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We investegated the effects of changing softening point of the ink binder resin and adding detergent to it on the recording sensitivity of dye transfer type thermal sheets. Falling down the softening point results in increase of sensitivity. However, the addition of some detergent with the low melting point was more effective. It is expected that the static sensitivity is improved by selecting suitable polymers coated on paper and adding some electron acceptors to them.
We have munufactured the experimental sheets possessing as sensitive as one of commercial thermal recording papers. Sample copies could be well received by G-II type facsimile.

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The multiply stacked layers of a-Si : H (F) and a-SiGe_x : H (F) have been prepared by hydrogen radical enhanced chemical vapor deposition (HR-CVD), in an attempt to fabricate near -ir photosensors. The high photoconductivity is obtained in the near-ir region due to the narrower gap a-SiGe_x : H (F) layers, while the dark conductivity is successfully suppressed by virtue of the potential fluctuation made at the conduction band in the multilayered structure. The electronic states in the gap are also discussed on the basis of measurements of the transient photocurrent and the photoconductivity spectroscopy.

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ZnSe is a semiconductor with a direct gap of 2.7 eV at room temperature and has potential applications for light emitting devices, photosensor and thin-film transistors.
We have prepared ZnSe films by Hydrogen Radical Enhanced Chemical Vapor Deposition. Highly (111) axis oriented ZnSe films have been prepared on glass substrates at 200°C. The temperature dependence of electrical conductivity in the dark and the photoconductive response suggests low density of defect states in the film. Epitaxial ZnSe films have been obtained on GaAs substrates at 200°C. n-type doping has been successfully carried out on epitaxial ZnSe films. In this paper, we discuss the transport process of the precursors and the deposition process.

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