JPH04331179A - Stencil printing device - Google Patents

Abstract

PURPOSE:To prevent bottom leakage in a stencil printing device wherein printing is performed by attaching a stencil paper on a porous cylindrical plate cylinder. CONSTITUTION:A cylindrical plate cylinder 1 comprises an ink passing part 2a and a non-passing part 2b. On the inner periphery of the cylindrical plate cylinder 1 which is situated on a rear end of an opening of a stencil paper 4 to be mounted on the outer periphery of the cylinder 1 and on a rear end of the ink passing part 2a, a protrusion 9 which engages with an ink roller 6 for supplying printing ink to be contacted to the inner periphery is formed.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to a stencil printing device,
More specifically, the present invention relates to preventing printing ink from leaking from the tail end of the stencil sheet mounted on the plate cylinder of the apparatus.

0002

[Prior Art] A cylindrical printing cylinder consisting of a porous support cylinder and a screen layer, on which a stencil original is mounted, and an ink supply supplying printing ink to the inner circumferential surface of the printing cylinder. It consists of a member part and a press roller that presses the outer peripheral surface of the plate cylinder, and the supplied printing ink passes through the support cylinder, the screen layer, and the stencil manuscript, is pressed by the press roller and oozes out, and the press roller and plate are pressed together. 2. Description of the Related Art Single-cylinder stencil printing apparatuses are known in which printing is performed on paper fed between cylinders. In this device, the supplied printing ink is pressed by a press roller, transferred to the paper, and is sequentially consumed.However, in the area outside the printing screen of the stencil paper, that is, in the non-perforated area, the printing ink is transferred to the outer peripheral surface of the plate cylinder and the stencil paper. During this period, excess ink is accumulated. When printing is performed over many sheets in this state, the amount of surplus ink gradually increases, and along with the squeezing effect of the press roller, it is pushed to the tail end of the stencil paper, and it protrudes from the tail end, staining the inside of the device. The so-called butt leak phenomenon occurs.

[0003] As a general measure to prevent this, the pressure of the press roller is released in front of the stencil paper to prevent excess ink from spilling out even if it accumulates, or the ink is attached to the stencil paper and thrown away when the stencil is ejected. The amount of ink is reduced. In addition, there are also
A rear end structure of a plate cylinder is known, which is described in Japanese Patent No. 3-101565 and the like.

[0004] The structure of the rear end of this plate cylinder was
In No. 8670, a weir made of an elastic, ink-impermeable material is disposed between a support cylinder that is a part of the plate cylinder and a screen layer, and excess ink is collected in the weir and then removed by a press roller. Excess ink is returned to the inside of the plate cylinder by pressure. On the other hand, in Utility Model Publication No. 63-101565, an opening for returning ink is provided in the plate cylinder, and a gutter-shaped guide member is provided with a gap on the outside of the plate cylinder, and this gutter-shaped guide member The ink is guided to the gap, collected, and the press roller presses the trough-shaped guide section to return excess ink to the inside of the plate cylinder.

[0005]

[Problems to be Solved by the Invention] However, in the case where excess ink is attached to the stencil paper, the ink is thrown away together with the stencil paper, which not only wastes the ink, but also
If a large amount of ink adheres to the base paper, it may adhere to the plate discharge device and cause malfunction. In addition, in the methods described in the above publications, the excess ink accumulated by the weir or gutter-shaped guide member is pushed out by the pressure of the press roller. If the amount of surplus ink increases, a problem arises in that it cannot be returned to the inside of the printing cylinder and the ink protrudes from between the stencil paper and the screen layer.

[0006]

[Means for Solving the Problems] Accordingly, the present invention provides a cylindrical printing cylinder consisting of a porous supporting cylinder and a screen layer mounted around the supporting cylinder, and a stencil paper is mounted on the outer circumferential surface; In a stencil printing device comprising an ink supply section that supplies ink to the inner circumferential surface of the plate cylinder, and a press roller disposed opposite to the outer circumferential surface of the plate cylinder, an ink passing section of the plate cylinder is provided. A protrusion was formed on the inner circumferential surface of the terminal end toward the inside of the plate cylinder.

[0007]

[Operation] The protrusion formed on the inner peripheral surface at the end of the ink passage section of the plate cylinder cuts off the contact between the ink supply section and the inner peripheral surface of the plate cylinder during printing, so that the ink supply section can be connected to the inner peripheral surface of the plate cylinder. The supply of printing ink to the plate cylinder is interrupted, and a gap is formed between the ink supply section and the inner circumferential surface of the plate cylinder, so that excess ink is returned to the inner circumferential surface of the plate cylinder through this gap. .

[0008]

[Example] A cylindrical plate cylinder 1 having a predetermined width is a support cylinder in which an ink passage portion 2a with numerous holes and an ink non-passage portion 2b with no holes are formed. 2 and
It is constituted by a screen layer 3 that covers about two-thirds of its outer peripheral surface in the circumferential direction and has a leather portion 3a at one end, and is driven to rotate clockwise around a central axis by an electric motor.

A stencil attachment portion 5 for retaining a stencil paper 4 is attached to the outer peripheral surface of the support cylinder 2 that is not covered by the screen layer 3, and a stencil sheet with one end thereof latched to the attachment portion 5 is attached. The base paper 4 is held in close contact with the outer peripheral surface of the stencil 1 due to the viscosity of the printing ink, and the ink passage section 2a is connected to the stencil paper 4.
It ends at a position corresponding to the rear end 4a of. Further, the screen layer 3 is provided with a razor portion 3a on the outer peripheral surface of the support cylinder 2 between the end portion 2c of the ink passage portion 2a and the base paper mounting portion 5.
It is attached to the outer circumferential surface of the support cylinder 2 so that the

An ink supply section consisting of an ink roller 6, a doctor roller 7, and an ink supply pipe 8 is disposed inside the plate cylinder 1. The ink roller 6 is rotatably supported by a support plate (not shown), has an axial dimension somewhat smaller than that of the plate cylinder 1, is disposed slightly apart from the inner peripheral surface of the plate cylinder 1, and is not shown in the figure. The plate cylinder 1 is rotated in the same direction as the plate cylinder 1 by a drive unit that does not have the plate cylinder 1. doctor roller 7
is supported above the ink roller 6 with a constant gap between it and the outer peripheral surface of the ink roller 6. An ink supply pipe 8 with an opening 8a facing downward is disposed above the doctor roller 7, and the ink supply pipe 8 supplies printing ink to the ink roller 6 from the opening 8a.

The doctor roller 7 stores printing ink supplied from the ink supply pipe 8 to the outer circumferential surface of the ink roller 6 on the outer circumferential surface of the ink roller 6, and prints in the gap formed between the outer circumferential surface and the ink roller 6. By passing the ink, a layer of printing ink with a uniform thickness is formed on the outer peripheral surface of the ink roller 6.

On the other hand, on the inner peripheral surface of the printing cylinder 1, which is located at the rear end 4a of the stencil paper 4 and near the end end 2c of the ink passage section 2a, a metallic protrusion 9 is formed toward the inside. ing. As shown in FIG. 2, this protrusion 9 has a thin trapezoidal shape with an upward slope to the right in the drawing at one end 9a on the advancing side of the plate cylinder 1, and as shown in FIG. They are arranged intermittently in parallel so as not to block the ink passage holes 2d. During printing, this protrusion 9 comes into contact with the outer peripheral surface of the ink roller 6 to form a gap 10 between the inner peripheral surface of the cylindrical plate cylinder 1 and the outer peripheral surface of the ink roller.

Returning to FIG. 1, below the plate cylinder 1, there is a press roller 11 which sandwiches the plate cylinder 1 and faces the outer circumferential surface of the plate cylinder 1. An arm portion is provided so as to be swingable by a support shaft 12. 13
is rotatably supported at the free end of the This press roller 11 is engaged with a paper detection member (not shown) except during printing, that is, when the ink non-passage portion 2b is located in the contact area between the ink roller 6 and the press roller 11, and the plate cylinder 1 However, during printing, that is, when the ink passage section 2a of the plate cylinder 1 is located in the contact area between the ink roller 6 and the press roller 11, the press roller 11 The engagement with the paper detection member is released and the paper is pressed into contact with the ink passage portion 2a.

With the above structure, a printing command is issued and the plate cylinder 1
When the ink roller 6 rotates and the ink passing portion 2a comes to the contact area between the plate cylinder 1 and the press roller 11 as shown in FIG. and the press roller 11. The press roller 11 is disengaged from a paper detecting member (not shown) in a standby state and presses the ink passage section 2a, and this pressing causes the inner circumferential surface of the plate cylinder 1 to come into pressure contact with the outer circumferential surface of the ink roller 6. Printing is performed on the paper 13 by the printing ink that has passed through the plate cylinder 1. At this time, the excess ink that has not been used for printing is pushed toward the rear in the traveling direction of the plate cylinder 1 by the squeezing action of the press roller 11, as shown in FIG.

As printing progresses and the protrusion 9 of the cylindrical plate cylinder 1 is applied to the ink roller 6, the inner circumferential surface of the plate cylinder 1 is separated from the ink roller 6, and the ink supply to the inner circumferential surface of the plate cylinder 1 is interrupted. Interrupted. At this time, the inner peripheral surface of the plate cylinder 1 and the ink roller 6
Since a gap 13 is formed between them, the forced surplus ink flows back through the ink passage section 2a from the outer circumferential surface of the plate cylinder 1 toward the inner circumferential surface of the plate cylinder 1, and passes through the gap 10 to the inner circumferential surface of the plate cylinder 1. Returned.

When the plate cylinder 1 rotates further and the ink-impermeable portion 2b comes to the contact area, the press roller 11 stops pressing against the plate cylinder 1 and enters a standby state, and printing on the first paper 13 is completed. Then, these operations are repeated when a new sheet is fed.

In this embodiment, the protrusion 9 is made of metal, but it can also be made of an elastic material such as resin or rubber, and the shape is not limited. Instead, a thin cylindrical member 9' as shown in FIG. 6 may be used. Further, the thickness of the protrusion 9 is such that there is little resistance to contact between the ink roller 6 and the inner circumferential surface of the plate cylinder 1, and the distance is 10.
The height to hold is good, specifically 0.1 to 0.5m.
m position is appropriate.

[0018]

According to the present invention, a protrusion is formed on the inner circumferential surface of the plate cylinder located at the rear end of the ink passing portion formed on the plate cylinder to return surplus ink to the plate cylinder. This prevents ink from accumulating at the rear end of the plate cylinder, which saves ink as it does not need to be thrown away with the base paper, and prevents malfunctions caused by leaked ink adhesion. Furthermore, ink leakage can be prevented with a simpler structure than conventional ink leakage prevention mechanisms.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram of a stencil printing apparatus using an embodiment of the present invention.

FIG. 2 is an enlarged perspective view of the main part of the present invention.

FIG. 3 is an enlarged perspective view of the main part of the present invention.

FIG. 4 is an operational diagram of a stencil printing device.

FIG. 5 is a side view showing the flow of excess ink.

FIG. 6 is a perspective view showing a modified example of the protrusion that protrudes from the main part of the present invention.

[Explanation of symbols]

1 Plate cylinder 2 Support cylindrical body 2a Ink passage section 2c Terminating end 3 Screen section 4 Stencil paper 6 Ink roller 7
Doctor roller 8 Ink supply pipes 6, 7, 8 Ink supply section 9 Projection

Claims (3)

[Claims] Claim 1: A cylindrical printing cylinder comprising a porous supporting cylinder and a screen layer attached around the supporting cylinder, a stencil paper is attached to the outer circumferential surface, and an ink is applied to the inner circumferential surface of the printing cylinder. In a stencil printing device comprising an ink supply section and a press roller disposed opposite to the outer circumferential surface of the plate cylinder, a stencil is provided on the inner circumferential surface of the terminal end of the ink passage section of the plate cylinder. A stencil printing device characterized in that a protrusion is formed inward. 2. The stencil printing apparatus according to claim 1, wherein the projections are arranged intermittently in parallel in the axial direction of the plate cylinder so as not to block the ink passage section. [Claim 3] The height of the protrusion is 0.1 to 0.5 mm.
The stencil printing apparatus according to claim 1 or 2, wherein: