Riso Kagaku Corporation

Riso Kagako Corporation

Katsuro Motoe

Shigenori Ishii

Yasuhiro Takahashi

Hideo Negishi

Yoshikazu Hara

Koji Nakayama

Mitsuru Takeno

Hitoshi Watanabe

Takeshi Saitoh

Toshihiro Bansyo

Masakazu Miyata

Hideaki Nogi

Hiroyasu Kato

Hisashi Sanagi

A stencil printing machine including a plurality of printing drums which are arranged to be spaced apart from each other such that respective axis lines thereof are respectively made horizontal and respective peripheral walls of which are wound with perforated stencil sheet, a stencil making unit for perforating the stencil sheet and a moving mechanism for supporting the stencil making unit to be movable relative to the respective printing drums.

Stencil printing machine

A stencil printing machine includes a squeegee roller in a printing drum having a peripheral wall having an ink-nonpermeable nonperforated portion around an ink-permeable perforated portion to have a stencil sheet and a printing the print sheet therearound. A projected portion is provided on the nonperforated portion. The thickness of the nonperforated portion is formed thicker than that of the perforated portion, and accordingly, press force exerted to the peripheral wall and the stencil sheet by the squeegee roller and the outer roller is enhanced on the nonperforated portion. Therefore, spread of ink is stopped within the perforated portion and ink is prevented from leaking from a gap between the outer peripheral face of the nonperforated portion of the peripheral wall and the stencil sheet.

In a stencil disposal unit and stencil disposal method for disposing a stencil clamped at and wound on a printing drum of a rotary stencil printing machine, the end part of the stencil sheet from a clamp is released, the printing drum is caused to rotate in a winding direction with respect to the end part of the stencil sheet released from the clamp, so as to guide the end part of the stencil sheet to a pull-in position, and the printing drum is caused to rotate in a reverse direction opposite to the winding direction, as pulling in the end part of the stencil sheet.

Stencil disposal unit and stencil disposal method

In the multi-drum type rotary stencil printer adapted to drive a plurality of printing drums altogether in synchronization with one another by a common drive mechanism, when one of the printing drums is placed out of engagement with a printing, a degradation of ink is anticipated in the temporarily rested printing drum due to its excessive stirring during an idling rotation. In order to avoid such an ink degradation, a clutch is incorporated in a route of transmitting a driving force from the common drive mechanism to each of the printing drums, so that the transmission of the driving force through each of the route can be selectively interrupted.

Multi-drum rotary stencil printer with each selected printing drum isolatable from rotation

To provide a stencil printer equipped with a carriage capable of stably and definitely conducting a leading end of a stencil sheet from a position at an outlet of a stencil sheet perforation device to a stencil sheet leading end mounting device of a printing drum and also capable of braking the stencil sheet so that the stencil sheet is wound around the printing drum according to its rotation under any optimum controlled expansion applied thereto, the carriage is provided with a stencil sheet leading end clamping device and a pair of stencil sheet leading end feeding rollers, separately, the stencil sheet leading end clamping device clamping the leading end of the stencil sheet when the carriage moves from the position at the outlet of the stencil sheet perforation device to the stencil sheet leading end mounting device of the printing drum, while the stencil sheet leading end feeding roller pair feeding out the stencil sheet leading end toward the stencil sheet leading end mounting device of the printing drum after the carriage has reached the vicinity of the stencil sheet leading end mounting device of the printing drum.

Stencil printer having carriage for guiding leading end of stencil sheet

In order to provide a drum type printer having a mechanism for adjusting a transverse position of a printed image improved such that when a plurality of drawout type drum units are used in the drum type printer, the transverse position of the printed image once adjusted with respect to each drum unit is preserved in each drum unit, wherein the adjustment of the position of the frame means,supporting the printing drum,relative to the machine frame,along the central axis of the printing drum is adjusted by an axial shifting of the shaft member,relative to the frame means,, a shaft member,being latched at its one end to the machine frame

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

A stencil printer has a printing drum which has an ink-permeable peripheral wall around which a stencil master is wound and to the inner surface of which ink is supplied. The printing drum is rotated about its longitudinal axis. An internal press roller is disposed inside the printing drum and is rotated in contact with the inner surface of the peripheral wall of the printing drum. A paper pinch drum is disposed outside the printing drum and is pressed against the peripheral wall of the printing drum with a printing paper pinched between the pinching means and the stencil master wound around the peripheral wall. A retainer roller is disposed in a predetermined position near the internal press roller and the inner surface of the peripheral wall downstream of the contact line between the internal press roller and the inner surface of the peripheral wall in the direction of rotation of the printing drum.

Stencil printer having printing drum and retainer roller

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.

To increase the degree of radial and axial alignments between a thermal head bar and a platen roller without being affected by the precision of manufacture and assembling of a cover adapted to be opened or closed by carrying either the thermal head bar or the platen roller in a thermal recorder, the thermal head bar is mounted to the cover or a housing of with two linear small plays and two small rotational plays, while forks provided at opposite longitudinal ends of the thermal head bar and radial cams provided at opposite ends of the platen roller are engaged with one another to restrict a radical alignment of the thermal head bar and the platen roller, while the fork provided at least at one longitudinal end of the thermal head bar and an axial cam provided at a corresponding end of the platen roller are engaged with one another to restrict an axial alignment of the thermal head bar and the platen roller.

Thermal recorder with means for improved alignment of thermal head bar

In a stencil printer, a printing drum is provided with a clamp plate for clamping an end portion of a stencil master, thereby holding the stencil master on the printing drum. A paper supply mechanism supplies printing sheets to the printing drum in synchronization with rotation of the printing drum. A first motor drives the paper supply mechanism by way of a first transmission mechanism, and a second transmission mechanism is operatively connected to the first transmission mechanism to be driven by the first motor by way of the first transmission mechanism, thereby rotating the printing drum. A phase adjustment mechanism driven by a second motor drives the second transmission mechanism with the first transmission mechanism held stopped, thereby changing the relative phases of rotation of the printing drum and sheet supply operation of the paper supply means. A drum position sensor generates a detecting signal upon detection that the printing drum comes to a reference position. The first motor is driven to rotate the printing drum and is stopped upon generation of the detecting signal. Then the second motor is driven to rotate the printing drum to the reference position.

Stencil printer and method of stopping in place printing drum of the

In the ink supply construction of a stencil printer, having an ink holding space 14 defined by an outer circumferential surface of an ink supply roller 4 and an ink supply control member 8, there is provided an ink interrupting member 30 as opposed to the ink supply control member across the ink holding space for restricting a side of the ink holding space opposite to the ink supply control member, in order to stabilize and highly uniformalize the cross sectional size of a rotating lump of ink L formed in the ink holding space along the length of the lump of ink. The lump of ink may be rotationally driven by an ink driving rod member 15 provided in the ink holding space. When the lump of ink is not rotationally driven by the ink driving rod member, the ink interrupting member may be constructed to rotationally drive the lump of ink.

Ink supply construction of printer having ink interrupting member

In a stencil sheet clamping construction for clamping a leading end portion of a stencil sheet to a stencil printing drum, a press plate is set at a half open position making an acute angle against an upper surface of a base portion when the leading end portion of the stencil sheet is mounted. This allows the leading end portion of the stencil sheet to be lifted above the upper surface of the base portion by floating up of an elastic film belt when the stencil sheet is discharged. This also prevents obstruction of the smooth advance of the leading end portion of the stencil when it is mounted due to the floating up of the elastic film belt.

Stencil sheet clamping construction of stencil printing drum with

A stencil printing drum includes a cylindrical circumferential wall which includes an ink permeable area and an ink impermeable area surrounding the ink permeable area. The wall is wrapped with a perforated stencil sheet and driven to rotate around a central axis of itself. The drum also includes an ink supply roller provided inside the wall for supplying ink to an inner surface of the wall. The roller presses ink outwardly from the ink permeable area to pass through a perforated area of the stencil sheet wrapped around the wall for printing. The drum also includes an ink impermeable projection. The projection is provided on a rear end portion of the ink permeable area in a rotating direction of the wall along one of the generatrices of the cylindrical wall. The projection projects inside the cylindrical wall, thereby dividing the ink permeable area and the ink impermeable area. The drum also includes an ink cover sheet provided on an outer surface of the cylindrical wall to cover an area ranging from the ink impermeable area to the ink impermeable projection. The ink cover sheet is fixed at a rear end portion thereof in the rotating direction of the wall. The cylindrical wall has an opening after the ink impermeable projection in the rotating direction and the opening is formed adjacent to the projection and along one of the generatrices of the cylindrical wall.

Stencil printing drum, with opening to allow ink return to inside of drum

A printing drum of a stencil printing machine is formed of a base member having two annular members spaced apart from each other and a transverse bar connecting the two annular members; a flexible multi-porous sheet having a filled portion at at least a part of a peripheral portion except a central portion thereof and being wrapped into a cylindrical shape around the outer peripheral surface of the base member, and around which a stencil sheet is wrapped; a spring member situated between one end of the flexible sheet and the base member to attach the flexible sheet resiliently on the base member; a stencil clamping device provided on the transverse bar for selectively clamping one end part of the stencil sheet; and an inner pressing device situated inside the flexible sheet for supplying ink outwardly. The inner pressing device pushes the flexible sheet radially outwardly when the base member and flexible sheet assembly rotates. Sliding areas are formed at portions of the annular members contacting the filling portion of the flexible multi-porous sheet. Thus, the flexible sheet can smoothly move on the annular members.

Stencil printing drum with friction reducing means

In a stencil printer having a printing drum 10 which has a circumferential wall portion for mounting a stencil sheet made of a flexible sheet member 20 and including a perforated portion 20c, an inking roller 12 provided inside of the printing drum for supplying ink to the printing drum from its inside with radially shifting out the perforated portion, and a back press roller 14 for supporting a print sheet against the printing drum by holding a leading end of the print sheet by a clamp 25, a means is provided for restricting the radial shifting out of the inking roller 12 when the inking roller is opposed by the clamp 25 to prevent ink leakage from the perforated portion 20c of the printing drum due to insufficient support of the print sheet by the back press roller 14 at the portion of the clamp 25. As an embodiment, an annular cam follower 23 mounted on the inking roller 12 is engaged by a cam 48 mounted on the back press roller.

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Ibaraki-ken, Japan

Katsuro Motoe