Riso Kagaku Corporation

Junnosuke Katsuyama

Takanori Hasegawa

Hideo Watanabe

Koichi Uchiyama

Kouichi Uchiyama

A stencil printing machine includes a main body; a covering openably attached to a surface of the main body and enclosing a space between the main body and the covering for storing a printing sheet and a stencil sheet therein; a flexible sheet attached to the covering so as to face the stencil sheet; a pressure reducing device disposed under the main body so as to communicate with the space and reducing pressure in the space; and a manual operating device for operating the pressure reducing device when being pressed downwardly from an operation start position that is substantially in the same level as the covering.

Stencil printing machine with pressure reduction chamber

A stencil printing apparatus is provided, which comprises a pressure chamber the wall of which is partly constituted by a flexible sheet member, a mount which is disposed in the pressure chamber opposite to the flexible sheet member and on which an article to be printed is placed, a frame for supporting a stencil between the flexible sheet member and the mount, and a pump for reducing pressure in the pressure chamber, in which the pump for reducing pressure is an air pump which comprises a cylinder connected to the pressure chamber and a piston slidably disposed in the cylinder. Stencil printing can be quickly and readily effect by pressure reduction in the pressure chamber. The printing apparatus can be small-sized, lightweight and simplified as a whole, and is improved in operatability.

Method and apparatus for pressure type stencil printing

The disclosed printing apparatus is includes an ink-permeable cylindrical printing drum which is rotated about an axis of rotation thereof with a heat-sensitive stencil sheet wound around the circumferential surface thereof; a liquid ejector which ejects a photothermal conversion material contained in a liquid to the heat-sensitive stencil sheet in accordance with image information, so that the photothermal conversion material is transferred to the stencil sheet as a reproduction of the image; a light which radiates a visible or infrared ray to the stencil sheet to which the photothermal conversion material has been transferred, such that the stencil sheet is perforated by heat emitted by the photothermal conversion material; and a presser which presses at least either the printing drum or printing sheet that is being moved in synchrony with the rotation of the printing drum, bringing the drum and printing sheet into close contact with each other, such that the stencil printing ink that is fed into the printing drum is transferred to the printing sheet through the perforated stencil sheet, in which the liquid ejector is further capable of ejecting a photothermal conversion material and/or a colorant contained in a liquid directly to the printing sheet in accordance with the desired image information, such that the image can be reproduced directly onto the printing sheet. Printing can be effected by two modes either stencil printing or printing directly from the liquid ejector. Upon perforation, the stencil sheet is not required to contact any substance, such as an original or a thermal printer head.

Printing apparatus for selectively supplying a photothermal

In a squeegee device for supplying ink in a stencil printing device from the interior of a cylindrical, ink permeable printing drum which rotates around an axial line thereof with a stencil master plate wrapped around the outer circumferential surface thereof, to prevent a squeegee blade from developing a juddering movement relative to the cylindrical printing drum, and to allow the squeegee blade to sufficiently intimately contact the inner circumferential surface of the printing drum so that printing ink may be supplied to the printing drum by a prescribed amount in a stable fashion at all times, a thin spring plate is placed on a reverse surface of the squeegee blade made of a rubber-like elastic material which is in engagement with the inner circumferential surface of the cylindrical printing drum. The spring property of the thin spring plate appropriately controls the elastic deformation of the squeegee blade, and, even when the squeegee blade is made of readily deformable rubber-like elastic material, and the increase in the rotational speed of the cylindrical printing drum is increased, the squeegee blade is prevented from developing a juddering movement relative to the cylindrical printing drum.

Squeege device for supplying ink in a stencil printing device

Ink leakage from the trailing edge of the stencil master plate is avoided and a stable ink supply is ensured when using a D-type printing drum including a concentric cylindrical part extending over a major part of an entire circumference of the printing drum and defining an ink permeable region, a non-concentric cylindrical or planar part extending over a minor part of an entire circumference of the printing drum and having a central axial line different from that of the concentric cylindrical part, and an outer circumferential surface on which a stencil master plate is to be mounted without losing the benefit of reducing the displacement of the press roller. A squeegee blade is in contact with the inner circumferential surface of the D-type printing drum, and, in order to maintain the contact between the squeegee blade and the inner circumferential surface of the D-type printing drum over its entire circumference and keep the contact pressure between the squeegee blade and the inner circumferential surface of the D-type printing drum at a prescribed level, a cam is provided for controlling the contact pressure between the squeegee blade and the inner circumferential surface of the D-type printing drum in synchronism with the rotation of the D-type printing drum.

Growing community of inventors

Tokyo, Japan

Junnosuke Katsuyama