JPH0576434B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a stencil printing apparatus, and more particularly to an ink supply system of a single-cylinder rotary stencil printing apparatus.

BACKGROUND TECHNOLOGY A mono-barrel rotary stencil printing device generally includes a cylindrical plate cylinder with a porous structure that rotates around its central axis and has a stencil printing paper wrapped around its outer circumferential surface, and a cylindrical plate cylinder that rotates around its central axis. An ink supply roller, generally called a squeegee roller, that contacts the inner circumferential surface of the cylindrical plate cylinder and rotates around its own central axis to supply printing ink to the inner circumferential surface of the cylindrical plate cylinder. This type of stencil printing device is known, for example, from Japanese Patent Application Laid-Open No.
-55889.

Problems to be Solved by the Invention In the stencil printing apparatus having the structure described above, the printing ink supplied to the inner peripheral surface of the cylindrical plate cylinder by the ink supply roller is applied to the cylindrical plate by the squeegee action of the ink supply roller. The excess printing ink passes through the perforated structure of the cylinder and is used to form the printed image, but as the cylindrical plate cylinder rotates, the excess printing ink is sequentially pushed to the lag side in the rotational direction, and when there is a large amount of excess printing ink, it is finally There is a risk that the so-called printing ink leaks out from the rear edge of the stencil printing paper that is wound around the outer peripheral surface of the cylindrical plate cylinder. This printing ink leakage phenomenon has been considered to be a troublesome problem.

An object of the present invention is to provide an improved stencil printing apparatus that solves the above-mentioned problems.

Means for Solving the Problems According to the present invention, the above-mentioned object is achieved by forming a part of the ink-impermeable structure and the rest of the ink-permeable structure, and having a stencil printing base paper wrapped around the outer peripheral surface. A cylindrical plate cylinder that rotates around its own central axis, and an inner peripheral surface of the cylindrical plate cylinder that contacts the inner peripheral surface of the cylindrical plate cylinder with its outer peripheral surface and rotates around its own central axis. an ink supply roller that supplies printing ink to the
When the ink supply roller corresponds to the boundary area between the ink-permeable structure portion and the ink-impermeable structure portion of the cylindrical plate cylinder, the pressing force of the ink supply roller against the inner circumferential surface of the cylindrical plate cylinder. This is achieved by a stencil printing device having a pressing force control means for releasing the pressure.

Effects and Effects of the Invention According to the above-described configuration, when the ink supply roller corresponds to the boundary region between the ink-permeable structure portion and the ink-impermeable structure portion of the cylindrical plate cylinder, the pressure on the cylindrical plate cylinder is reduced. By releasing the squeegee action of the printing ink by the ink supply roller, the printing ink is prevented from being pushed to the lag side in the rotational direction as the cylindrical plate cylinder rotates, and the phenomenon of bottom leakage of the printing ink occurs. is avoided.

When the ink supply roller corresponds to the boundary area, the pressure on the cylindrical plate cylinder is released and the ink supply roller may be separated from the inner circumferential surface of the cylindrical plate cylinder. In this case, the ink supply roller corresponds to the boundary area. At the corresponding time, the squeegeeing effect of the printing ink by the ink supply roller is released and the ink supply to the cylindrical plate cylinder is completely interrupted, so that the effect of avoiding the printing ink leakage phenomenon becomes even more remarkable.

EXAMPLES The present invention will now be described in detail by way of examples with reference to the accompanying drawings.

The attached drawings show the main parts of one embodiment of a stencil printing apparatus according to the present invention. In the figure, reference numeral 1 indicates a cylindrical plate cylinder, and the cylindrical plate cylinder has a land member 3 for clamping the base paper on a part of its outer circumferential surface.
a metal support cylinder 2 having a support cylinder 2;
intermediate screen layer 4 wrapped around the outer peripheral surface of
and an outer screen layer 5 which is wound around the outer circumferential surface of the intermediate screen layer 4. The ink-permeable structure part 7 has a porous structure having a large number of small holes (not shown) for passing ink in other parts except for the part where the base paper clamp land member 3 is attached and the surrounding part has no small holes. The ink-impermeable structure 8 has a non-porous structure.

A permanent magnet 9 is attached to the base paper clamp land member 3.
is fixed, and also rotates around a pivot 10 to grip one end of the stencil printing base paper S and attach a permanent magnet 9.
Clamp piece 1 made of thin metal plate that is magnetically attracted to
1 is installed.

On the outer peripheral surface of the cylindrical plate cylinder 1, a stencil printing base paper S having a constant length is attached at one end to a permanent magnet 9.
The stencil printing base paper S is wrapped around the cylindrical plate cylinder 1 while being held by the clamp pieces 11 and 11, and the trailing edge of the stencil printing base paper It is located closer to the ink-impermeable structure portion 8 than the boundary with the ink-permeable structure portion 8 .

A holder plate 12 for an ink supply device is arranged in the cylindrical plate cylinder 1 . One end of a squeegee roller support arm 14 is rotatably attached to the holder plate 12 by a pivot 13. The squeegee roller support arm 14 rotatably supports a squeegee roller 15 about its central axis 16, and the squeegee roller 15 is adapted to come into sliding contact with the inner peripheral surface of the cylindrical plate cylinder 1 at its lower region. One end of a pressing force adjustment arm 17 is rotatably attached to the central shaft 16 of the squeegee roller 15, and the other end of the pressing force adjustment arm 17 is connected to an eccentric cam 20 by a screw 19 engaged with a long hole 18. It is fixed to the squeegee roller support arm 14 at a rotational position adjusted by. A cam follower roller 22 of a rolling type is rotatably attached to the intermediate portion of the pressing force adjusting arm 17 by a shaft 21 . Holder plate 1
2 has a cam 24 for adjusting the pressing force by means of a cam shaft 23.
is rotatably mounted. Pulleys 25 and 26 are attached to the central shaft 16 and the camshaft 23, respectively, and these pulleys 25 and 26 are drivingly connected to a drive pulley 28 by an endless belt 27, and synchronized with the rotation of the cylindrical plate cylinder 1. The plate cylinder 1 rotates once per rotation of the cylindrical plate cylinder 1 in the same direction as the rotation direction of the cylindrical plate cylinder 1.

The pressing force adjustment cam 24 has a recessed portion 24 at one location.
b, and when engaged with the cam follower roller 22 at the normal circumferential portion 24a other than the recessed portion 24b, the squeegee roller 15 is pressed against the inner circumference of the cylindrical plate cylinder 1 with a predetermined pressing force. On the other hand, when the squeegee roller 15 is engaged with the cam follower roller 22 at the recessed portion 24b, the pressure of the squeegee roller 15 against the cylindrical plate cylinder 1 is released. The pressing force adjustment cam 24 is arranged so that the squeegee roller 15 is wound around the boundary area between the ink-permeable structure portion 7 and the ink-impermeable structure portion 8 of the cylindrical plate cylinder 1, in other words, the outer peripheral surface of the cylindrical plate cylinder 1. The recessed portion 24b engages with the cam follower roller 22 at a rotational position corresponding to the trailing edge region of the stencil printing base paper S that is attached, that is, the region indicated by A in the figure. Its phase is set.

A tension coil spring 29 is attached to the squeegee roller support arm 14 and the holder plate 12, and the tension coil spring 29 lifts and biases the squeegee roller support arm 14 in the direction of releasing the pressing force.

The holder plate 12 supports a doctor rod 30 parallel to the squeegee roller 15, and the doctor rod 30 has a long hole 3 provided in the holder plate 12 with a protruding shaft portion 31 provided at both ends thereof.
2 is engaged. A stay rod 33 penetrates through the protruding shaft portion 31, and the stay rod 33 has its tip portion connected to a connecting block 34 rotatably supported by the center shaft 16 of the squeegee roller 15, and the nut 3 is attached to the connecting block 34.
5 is fixed with screws. Projecting shaft part 3
A compression coil spring 36 is installed between the doctor rod 30 and the connecting block 34 so as to surround the stay rod 33.
is urged away from the squeegee roller 15, and the squeegee roller 15 and doctor rod 3 are always
0, a very small gap 37 is created between the two.

A press roller 38 is provided on the outside of the cylindrical plate cylinder 1. During normal printing operation, the press roller 38 is pressed towards the outer circumferential surface of the cylindrical plate cylinder 1 when it corresponds to the ink-permeable structure 7, whereas when it corresponds to the ink-impermeable structure 8 The press roller 38 is separated from the outer peripheral surface of the cylindrical plate cylinder 1, and the operation of the press roller 38 may be similar to that of a conventionally known general stencil printing device.

The squeegee roller 15 is driven by a pulley 26 to rotate counterclockwise about its own central axis in synchronization with the rotation of the cylindrical plate cylinder 1 in the same direction as the rotational direction of the cylindrical plate cylinder 1. The printing ink P in the ink pool formed in the wedge-shaped space between the squeegee roller 15 and the doctor rod 30 is supplied from the ink supply pipe 39 to the squeegee roller 1.
5 passes through the gap 37 and adheres to the outer circumferential surface of the squeegee roller 15 in the form of a layer with a thickness of several microns determined by the size of the gap 37, and is sent to the inner circumferential surface of the cylindrical plate cylinder 1.

At this time, printing paper (not shown) is supplied between the cylindrical plate cylinder 1 and the press roller 38 in synchronization with the rotation of the cylindrical plate cylinder 1, and the printing paper is shaped into a cylindrical shape by the press roller 38. The printing ink that is pressed against the stencil printing paper S which is wrapped and attached to the outer peripheral surface of the plate cylinder 1 and has passed through the ink-permeable structure part 7 of the cylindrical plate cylinder 1 and the perforated part of the stencil printing paper S is It is applied to carry a printed image by printing ink.

When the squeegee roller 15 is in a position corresponding to the ink-permeable structure portion 7 of the cylindrical plate cylinder 1,
In other words, when the cylindrical plate cylinder 1 is in a rotational phase in which the ink-permeable structural portion 7 is in sliding contact with the squeegee roller 15, the pressing force adjusting cam 24 normally engages with the cam follower roller 22 at the circumferential portion 24a. As a result, the squeegee roller 15 is pressed against the inner circumferential surface of the cylindrical plate cylinder 1 with a predetermined pressing force, and the squeegee roller 15 performs the required squeegee action to press against the cylindrical plate cylinder 1. Printing ink is supplied.

When the rotation of the cylindrical plate cylinder 1 progresses and the squeegee roller 15 comes to a position corresponding to the boundary area between the ink-permeable structure portion 7 and the ink-impermeable structure portion 8 of the cylindrical plate cylinder 1, the squeegee roller 15 moves. This corresponds to the rear edge area of the stencil printing base paper S which is wound and attached to the outer peripheral surface of the cylindrical plate cylinder 1, and at this time, the pressing force adjustment cam 24 is engaged with the cam follower roller 22 at the recessed part 24b. As a result, the pressure of the squeegee roller 15 on the cylindrical plate cylinder 1 is released, and at the same time, the squeegee roller 15 is lifted together with the squeegee roller support arm 14 by the spring force of the compression coil spring 29, and the squeegee roller 15 is lifted up by the spring force of the compression coil spring 29, and the squeegee roller 15 is lifted up with the squeegee roller support arm 14 by the spring force of the compression coil spring 29. Printing ink is not supplied to the portion of the cylindrical plate cylinder 1 which is separated from the inner circumferential surface and where the trailing edge region of the stencil printing paper S which is wrapped and attached to the outer circumferential surface of the cylindrical plate cylinder 1 is located. Further, in this portion, the squeegee action of the squeegee roller 15 is released. As a result, printing ink is not supplied to the portion corresponding to the trailing edge region of the stencil printing base paper S, and moreover, the printing ink contained in the cylindrical plate cylinder 1 is distributed in the direction of rotation of the cylindrical plate cylinder 1. This prevents excess printing ink from being pushed to the lag side, and the occurrence of so-called bottom leakage phenomenon in which excess printing ink leaks out from the rear end of the stencil printing paper S is avoided.

The pressure of the squeegee roller 15 on the cylindrical plate cylinder 1 is released from the boundary between the ink-permeable structure part 7 and the ink-impermeable structure part 8 of the cylindrical plate cylinder 1 on the outer peripheral surface of the cylindrical plate cylinder 1. It starts at a position approximately 10 mm before the rotation direction (advanced side in the rotation direction) in the circumferential direction, and the trailing edge of the stencil printing base paper S that is wrapped and attached to the outer peripheral surface of the cylindrical plate cylinder 1 is located. It may end at a position on the outer peripheral surface of the cylindrical plate cylinder 1 at a position on the rotational direction lag side by about 10 mm or more in the circumferential direction.

Although the present invention has been described in detail with respect to specific embodiments above, the present invention is not limited thereto, and various embodiments are possible within the scope of the present invention. It will be clear to those skilled in the art.

[Brief explanation of the drawing]

The attached figure is a longitudinal sectional view showing the main parts of one embodiment of the stencil printing apparatus according to the present invention. DESCRIPTION OF SYMBOLS 1... Cylindrical plate cylinder, 2... Support cylinder, 3... Land member for base paper clamp, 4... Intermediate screen layer body,
5... Outer screen layer, 7... Ink-permeable structural portion, 8... Ink-impermeable structural portion, 9... Permanent magnet, 10... Pivot, 11... Clamp piece, 12... Holder plate, 13... Pivot, 14... Squeegee Roller support arm, 15... Squeegee roller, 16...
Central axis, 17...Pushing force adjustment arm, 18...Long hole,
19...Screw, 20...Eccentric cam, 21...Shaft, 22...
Cam follower roller, 23...camshaft, 24...pressing force adjustment cam, 25, 26...pulley, 27...endless belt, 28...drive pulley, 29...tension coil spring, 30...doctor rod, 31...protruding shaft portion, 3
2... Elongated hole, 33... Stay rod, 34... Connecting block, 35... Fixing nut, 36... Compression coil spring, 37... Gap, 38... Press roller, 39... Ink supply pipe.

Claims (1)

[Claims] 1. A cylindrical plate cylinder that rotates around its own central axis, with part of it having an ink-impervious structure and the rest having an ink-permeable structure, with stencil printing paper wrapped around the outer circumferential surface, and a cylinder that rotates around its own central axis. an ink supply roller that contacts the inner peripheral surface of the cylindrical plate cylinder and rotates around its own central axis to supply printing ink to the inner peripheral surface of the cylindrical plate cylinder; a pressing force control means for releasing the pressing force of the ink supply roller against the inner circumferential surface of the cylindrical plate cylinder when the ink supply roller corresponds to a boundary area between the ink-permeable structural part and the ink-impermeable structural part of the plate cylinder; A stencil printing device that has a