It has been recently attempted to improve the printing speed of Dye Diffusion Thermal Transfer (D2T2). However, it has been pointed out that the crease of printing film is caused in high speed printing. Therefore, it is necessary to investigate thermal creep properties of film heated by thermal pulse under weighting.
The thermal creep properties of four kinds of PET base films (A-D) was measured by the new method developed in our laboratory. Two types dependence of thermal creep on temperature were obtained in the measurement. All of four kinds of films indicate the thermal creep of type I i.e. elongation at low temperature and of type II i.e. shrinkage at high temperature. These thermal creep properties suggest that the crystal structure of PET base film changes from fringed micelle state to folding state at high temperature.
A and B strongly shrunk by thermal pulse when it was weighted to MD direction at high temperature. Otherwise C and D strongly shrunk by thermal pulse when it was weighted to TD direction at high temperature. There is the linear relation between dynamic data of shrinkage ratio (ΔFMD/ΔFTD) and static ratio (MD/TD) data measured by conventional method.
Hence, the dynamic thermal creep properties of the high polymer can be measured by our newly developed method.

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Influence of parameters of magnetic carriers on their cleaning characteristics was examined in an electrophotographic imaging system without cleaning unit, in which the residual toner on the photoconductor was cleaned by the carrier beads at the developing stage simultaneously. Several magnetic carriers with various saturation magnetization, shape, electric resistivity and particle size were prepared for this study, based on both iron and ferrite.
The carrier with higher saturation magnetization showed lower memory effect and better resolution by less residual toner on the photoconductor. The iron carrier with irregular shape showed better background density, which was attributable to a larger specific surface area of the carrier. The carrier with higher electric resistivity showed lower image and background densities, and gave less residual toner on the photoconductor. The recovery of residual toner from the photoconductor by the developer was independent of the electric resistivity of the carrier. The smaller size iron carrier gave a lower background density because of its high toner triboelectric charge. The recovery of the residual toner by the developer was almost independent of their particle sizes. The optimum condition for the cleaning-unit-free system was confirmed by using the irregular shape iron carrier of 30 μm in particle size.

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The control of powder motion is important in applications such as electronic printing. The conductive powder (toner for electronic printing, diameter about 8-13 μm, resistivity 10⁶ Ωcm) is sprayed freely on the electrode. When more than a certain value of electric field is applied between the electrodes, the powder starts to move up and down between the electrodes by electrostatic force (induced charge x electric field). By using an electrode which is dented to a thin lens shape, it is found that the conductive powder is confined between the electrodes in the dented area.

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