In a electrophotographic printer without a decurler device, amount of paper curl depends on geometry of its transportation path. However, since the paper path affects whole layout of the machine, it may not be modified even if the paper curl becomes out of acceptable range. To overcome the difficulty, a simulation model to predict the paper curl formed by the transportation path geometry is constructed so that the paper path can be designed considering paper curl at the early stage of development. The mechanical characteristics of paper is measured by the thermo-mechanical analyzer, and expressed as a double Maxwell model. Given fuser device and paper condition, the paper curl is calculated using the time variation of paper deflection during transportation. Using a commercial laser printer and three different types of paper, it is verified that the present simulation model is able to predict paper curl with satisfactory accuracy.

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This paper focuses on the patent for Thermo-Responsive Recording Sheet, which was filed by NCR. This is the first patent for utilizing the color developing reaction between leuco dye and developer.

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This paper focuses on the patent for inkjet, which was filed by Siemens-Elema. This is the early patent on measuring instrument (Electrocardiograph) based on ink jet technology.

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This article concentrates on a patent of Thermal Print Head, filed by NCR. This is a basic patent of the thermal print head which formed thermal resistive elements on a substrate edge.

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This paper focuses on the first patent applied by George Eastman, the founder of Eastman Kodak Company. This invention is about manufacturing method and apparatus of photographic dry-plate by coating of gelatin-AgX photographic emulsion on glass. This patent contributed to the foundation of Eastman Kodak Company.

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This paper presented the well-known patent for “Electrophotography”, which was filed by Chester F. Carlson in1939. The patent provided five sub-processes;charge, exposure, development, transfer and fusing, which are commonly used at now.

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A patent for Phototelegraphic Method by Japanese original technology is focused in this paper. The patent was invented by Yasujiro Niwa, NEC Corporation, This is the basic patent on transmission signal formation for photographic images. The device, to which this method was applied, was used for broadcasting press photographs for the coronation ceremony of the Showa Emperor in 1928.

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