Riso Kagaku Corporation

Hiroyasu Kato

Sadanao Okuda

Katsuro Motoe

Takashi Isozaki

Yasushi Kuratani

Kenji Suzuki

By preventing a deformation of printing drum of a rotary stencil printing apparatus caused at the time of printing, uniform printed images can be printed even under conditions such as low temperature and high-speed printing and even using an apparatus provided with a large-sized drum. That is, the invention provides a method for stencil printing which comprises winding a perforated stencil sheet around the peripheral wall of a cylindrical printing drum having an ink permeable peripheral wall and rotating around its central axis, supplying an ink to the peripheral wall from the inside of the drum at the time of rotation of the drum, and pressing a printing paper to the outer surface of the peripheral wall of the drum to transfer the ink to the printing paper through the stencil sheet, wherein the peripheral wall of the drum has such a strength that the peripheral wall shows a stress of 0.75 kgf/cm,or more, preferably 1.4 kgf/cm,or more when it is deformed by 0.1 cm in a direction towards its central axis and viscosity of the ink is 330 Pa&bull;s or lower, preferably 150 Pa&bull;s or lower. An apparatus for carrying out the stencil printing is also provided.

Method and apparatus for stencil printing

A printing drum (,) is supported by a first frame (,) to be rotatable around its central axis (,). The first frame (,) is supported by a second frame (,) to be movable relative to the second frame (,) along the central axis (,) for at least a distance corresponding to a maximum value of an adjustment of a transverse position of a printed image. The second frame (,) is removably mounted to a machine frame (,), wherein the first frame (,) is moved relative to the second frame (,) only for a distance required for an adjustment of a transverse position of a printed image.

Drum type printer having mechanism for adjusting transverse position of printed image

In a couple of axially engageable/disengageable gear wheels for driving a printing drum, in which each gear wheel has a duplicate construction including a primary gear for transmission of a power for driving the printing drum and an auxiliary gear for suppressing a backlash, the primary gear and the auxiliary gear are shifted relative to one another in the phase, except a predetermined meshing area, so that the two duplicate gear wheels are allowed to disengage from and re-engage with one another only when the two gear wheels are rotationally positioned at a predetermined rotational relationship.

Couple of gear wheels for driving printing drum with means for mutual

In an ink blocking member for a rotary stencil printing machine in which a printing drum has a printing region which is ink-permeable and a non-printing region which is not ink-permeable, for closing a part of the printing region, the ink blocking member is provided on the outer surface of the rear part of the printing region as viewed in the direction of rotation of the printing drum. The ink blocking member defines a space on the outer surface of the printing region of the printing drum which is opened in the direction of rotation of the printing drum, and which is communicated through the printing region with the inside of the printing drum. The ink blocking member is restorable in configuration to maintain the space constant in volume.

Ink blocking member in rotary stencil printing machine and printing drum

An ink supply device for a printing apparatus, the ink supply device being positioned within a porous cylindrical drum and including: a frame body having side plates confronting each other; an ink supply roller supported between the side plates by the frame body, a lower portion of the ink supply roller coming in contact with an inner circumferential surface of the cylindrical drum, and the ink supply roller being rotatable about a central axis thereof and in synchronism with the rotation of the cylindrical drum; an ink amount control member supported between the plates by the frame body, and having a predetermined gap with respect to an outer circumferential surface of the ink supply roller while extending along one generatrix of the ink supply roller, wherein the ink amount control member, the ink supply roller and the side plates cooperate to form a space in which ink is pooled; a rodlike member supported between the side plates by the frame body and extending within the space where ink is pooled along the generatrix of the ink supply roller; an ink distributor supported by the frame body and positioned above the ink supply roller; and grooves arranged on the ink amount control member, for spreading ink in the space where ink is pooled along the generatrix of the ink supply roller while the ink supply roller is being rotated.

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Inashiki-gun, Japan

Hiroyasu Kato