Riso Kagaku Corporation

Asahi-dow Limited

Yoshio Tsuji

Takanori Hasegawa

Noboru Hayama

A stencil paper assembly comprising a stencil paper sheet and an ink-impermeable sheet laid one over the other, said assembly being adapted to maintain a layer of ink between said stencil sheet and said ink-impermeable sheet so that numerous printed sheets may be obtained with one charge of ink and without causing smearing of ink.

Stencil paper assembly

A stencil sheet having a thin stretched thermoplastic resin film supported on an ink pervious porous substrate is positioned on an original manuscript in a manner such that the film may be in close contact with the imaged side of the manuscript. The assembly is then irradiated by a light which is rich in rays having a wavelength ranging from 0.7 to 1.2 microns and has a flash duration of from 10.sup.-4 to 10.sup.-3 second. A xenon-filled electronic flash discharge tube is found to be the most suitable light source. Stencil openings formed thereby on the film surface are excellent in definition and free from marginal swelling therearound. The stencil prepared by this method can produce copies of 2000 or more which correspond exactly with the original manuscript.

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Tokyo, Japan

Yoshio Tsuji