JPH0349980A - Screen printing apparatus - Google Patents

Abstract

PURPOSE:To prevent the generation of the ink sump between a plate cylinder and the screen printing base paper and the protrusion of ink at the terminal part of screen printing raw paper by bringing a press roller into contact with the plate cylinder under pressure on a paper discharge side from the axial line passing through the center of the plate cylinder and that of a squeezee roller. CONSTITUTION:The press roller 4 brought into contact with a plate cylinder 20 under pressure while rotated in the direction shown by an arrow r3 in synchronous relation to the plate cylinder 20 is provided on the outer peripheral side of the plate cylinder 20 opposed to a squeezee roller 3 and the center C3 of the press roller 4 is provided at a position shifted to a paper discharge part by a distance (a) from the axial line (l) connecting the center C1 of the plate cylinder 20 and the center C2 of the squeezee roller 3. Therefore, the contact region S2 only of the press roller 4 and the plate cylinder 20 is wider than the region S1 where both of the squeezee roller 3 and the press roller 4 are in contact with the plate cylinder 20. As a result, the ink 6 supplied to the outside of the plate cylinder in the S1-region is again recovered in the plate cylinder within the wide contact region S2 in a high recovery rate and, therefore, even when the number of printing papers increases, the ink between the plate cylinder 20 and screen printing raw paper 10 does not increase and the generation of an ink sump can be prevented. The protrusion of the ink 6 at the terminal part of the raw paper can be also prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a stencil printing device that has been improved to prevent ink from pooling between a plate cylinder and stencil paper and from spilling out at the end of the stencil paper.

(Prior Art) Conventionally, as this type of printing device, one shown in FIG. 4 is known.

In the figure, 20 is a cylindrical plate cylinder around which the stencil paper 0 is wound, and the plate cylinder 20 includes a metal cylindrical body 1 and a metal cylindrical body 1 in which a large number of holes 1a, la, . Similarly, the screen layer 2 is made of stainless steel fiber or the like and is provided with a large number of permeable holes through which ink 6 passes, and rotates counterclockwise (in the direction of arrow r, force) during printing.

Furthermore, a squeegee roller 3 whose outer circumferential surface is arranged at a predetermined distance from the inner circumferential surface of the plate cylinder 20 is disposed within the plate cylinder 20;
A doctor rod 5 is provided with a predetermined gap from the squeegee roller 3, and when the squeegee roller 3 is rotated in the direction of arrow r2 in synchronization with the rotation of the plate cylinder 20, ink is removed from the ink supply vibrator 8. The ink 6 supplied to the reservoir 6a is supplied between the plate cylinder 20, which is the inner peripheral surface of the plate cylinder 20, and the squeegee roller 3.

When a place roller 4 (described later) is pressed against the plate cylinder 20 side, the ink 6 supplied between the squeegee roller 3 and the plate cylinder 20 is transferred to the metal cylinder. Hole of body 1]a and screen layer 2
is transmitted between the plate cylinder 20 and the stencil paper 10.

On the other hand, 4 is an axis connecting the center C1 of the plate cylinder 20 and the center C2 of the squeegee roller 3! When printing paper P is fed between the plate cylinder 20 and the press roller 4, the press roller is arranged so as to be able to approach and separate from the plate cylinder 20 so that the center position C3 is on the extension line of the press roller 4. Pressing against the plate cylinder 20 while rotating,
The ink 6 supplied between the plate cylinder 20 and the stencil paper 10 is transferred to the printing paper P side through the perforations of the stencil paper 10 to perform printing.

(Problem to be Solved by the Invention) However, in conventional devices such as bipedal devices, the axis connecting the center C1 of the plate cylinder 20 and the center C2 of the squeegee roller 3! Since the center C3 of the press roller 4 is located on the extension line of , there is a problem that ink pools are formed during printing as described below.

That is, as shown in FIG. 4, the supply area of the ink 6 supplied between the plate cylinder 20 and the stencil paper 10 from the squeegee roller 3 side is centered around the axis l, which is the contact area between the squeegee roller 3 and the plate cylinder 20. There is an S+ region with a constant width.

Therefore, when printing is performed by pressing the press roller 4, first the ink 6 in the S1 area passes through the perforations in the stencil paper 10 and is transferred to the printing paper P side, but the ink in the non-perforated areas or The remaining ink that has not been transferred still remains between the plate cylinder 20 and the stencil paper 10.

On the other hand, pressure contact is made with the press roller in the region S, and in this case, the 82 region on the paper discharge side is the contact region between only the press roller 4 and the plate cylinder 20. Therefore, when there is a pressing operation by the press roller 4, the ink 6 remaining between the printing cylinder 20 and the stencil paper 10 is returned to the printing cylinder 20 due to the pressing contact between the printing cylinder 20 and the press roller 4 in the area 82. It's been like going back.

By the way, the size of the area S where both the squeegee roller 3 and the press roller 4 are in contact with the plate cylinder 20, and the area S where only the press roller 4 is in contact with the plate cylinder 20 on the paper discharge side.
Comparing the sizes of the two areas, the area S2 is only slightly larger than the area S1. This matter, S.
This means that the ink 6 supplied outside the plate cylinder in the area S2 cannot be sufficiently recovered into the plate cylinder in the area S2. Also, plate cylinder 2
Since the ink 6 always tends to come out of the plate cylinder due to the centrifugal force generated with the rotation of the plate cylinder, recovery of the ink 6 into the plate cylinder is inhibited.

Therefore, as the number of printing increases, the amount of ink between the plate cylinder 20 and the stencil paper 10 increases, resulting in the formation of so-called ink pools between the plate cylinder 20 and the stencil paper 10.

If ink accumulates between the plate cylinder 20 and the stencil paper 10 in this way, thin or small letters may become unclear due to oversupply of ink, or the stencil paper 10 may not be wrapped around the plate cylinder 20 sufficiently. Therefore, there are problems in that the stencil paper 10 is wrinkled during printing, and that ink is wasted because the stencil paper 10 is discarded together with the ink adhered to the surface of the printing cylinder when the printing plate is discharged.

Further, when an ink pool occurs between the plate cylinder 20 and the stencil paper 10 as described above, this surplus ink moves toward the end portion 10a of the stencil paper 10 as printing is repeated, and furthermore, the stencil paper 10 There is a problem in that the ink 6 that protrudes from the terminal end 10a of the printing paper 10 stains the printing paper P and the press roller 4.

This invention was made in view of the above-mentioned problem, and by pressing the press roller on the paper ejection side from the axis passing through the center of the plate cylinder and the center of the squeegee roller, ink does not accumulate between the plate cylinder and the stencil paper. An object of the present invention is to provide a stencil printing device which does not cause ink to occur and also prevents ink from spilling out at the end of a stencil sheet.

(Means for Solving the Problems) In order to solve the above problems, the present invention includes a cylindrical plate cylinder, a squeegee roller installed in the plate cylinder and supplying ink to the inner peripheral surface of the plate cylinder, A press roller arranged so as to be able to come into contact with and separate from the outer peripheral surface of the printing cylinder,
In a stencil printing device in which two legs are wrapped around a cylindrical plate cylinder and a press roller presses the printing paper against the stencil paper to perform printing, the press roller passes through the center of the plate cylinder and the center of the squeegee roller. It is characterized by being in pressure contact with the plate cylinder on the paper discharge side from the axis.

(Function) In this invention, since the press roller is brought into pressure contact with the plate cylinder on the paper discharge side from the axis passing through the center of the plate cylinder and the center of the squeegee roller, the press roller and the plate that collect ink in the plate cylinder are The area of contact with the cylinder on the paper discharge side is widened, and the ink supplied outside the plate cylinder is collected into the cylinder more efficiently than in the past.

(Explanation of Examples) Next, embodiments of the present invention will be described based on the drawings.

Note that the same reference numerals are given to the same constituent parts as those used in the explanation of the above conventional example.

FIG. 1 is an overall configuration diagram of an embodiment of an apparatus to which the present invention is applied, and FIG. 2 is an enlarged view of the main parts of FIG. 1.

In FIG. 1, reference numeral 20 denotes a cylindrical printing cylinder around which the stencil paper 10 is wound, and has a number of holes 1a and 1 through which ink 6 passes.
a... is formed into a mesh-like metal cylindrical body 1;
It is composed of a mesh screen layer 2 made of stainless steel fiber or the like, and is configured to be rotationally driven in a counterclockwise direction (direction of arrow r1) in FIG. 2 by a motor (not shown).

Further, the cylindrical plate cylinder 20 has a stencil paper 10 attached to a part of its outer periphery.
It has a base paper attachment part 7 that locks one end, and the stencil paper 10 that is secured to this base paper attachment part 7 is tightly attached to the outer peripheral surface of the cylindrical plate cylinder 20 due to the viscosity of the printing ink, and is held. and rotates integrally with the cylindrical plate cylinder 20.

Inside the cylindrical plate cylinder 20, a squeegee roller 3 with a smaller diameter is arranged. When the plate cylinder 20 rotates once, it rotates at least once around its own central axis C2 in the counterclockwise direction (arrow r2 direction) in FIG.

Further, a doctor rod 5 is disposed within the cylindrical plate cylinder 20 along the generatrix of the squeegee roller 3 at a predetermined distance d from the outer circumferential surface of the roller. This doctor rod 5 may or may not be rotatable. In addition, in FIG. 2, above the doctor rod 5,
An ink supply pipe 8 is provided on the lag side of the squeegee roller 3 in the rotational direction, and the ink 6 is supplied through the ink supply pipe 8. The supplied ink 6 forms an ink reservoir 6a in a wedge-shaped space formed by the outer peripheral surface of the squeegee roller 3 and the outer peripheral surface of the doctor rod 5.

Ink 6 is supplied to the ink supply pipe 8 by an ink supply pump (not shown). The ink supply pipe 8 discharges printing ink when the size (ink amount) of the ink reservoir 6a becomes less than a predetermined value, and on the other hand, when the size of the ink reservoir 6a becomes less than a predetermined value, printing ink is discharged. It is controlled to stop printing and replenish printing ink so as to keep the size of the ink reservoir 6a substantially constant.

Further, a press roller 4 is provided on the outer peripheral side of the plate cylinder 20 facing the squeegee roller 3 and is pressed against the plate cylinder 20 side while rotating in the direction of arrow r3 in synchronization with the plate cylinder 20. When the printing paper P is fed between the press rollers 4, the printing paper P is configured to be printed by the press rollers 4 coming into pressure contact with the plate cylinder 20 side.

In this embodiment, the center C3 of the press roller 4 is the axis connecting the center C1 of the plate cylinder 20 and the center C2 of the squeegee roller 3! It is provided at a position shifted by a distance a toward the paper discharge side.

The device of this embodiment is constructed as described above, and its operation will be explained next.

When a printing cylinder drive motor (not shown) is turned on, the printing process is started and the printing cylinder 20 rotates in the direction of arrow r1, which causes the squeegee roller 3 to rotate in the direction of arrow r2. The printing ink 6 in the ink reservoir 6a flows counterclockwise around an axis parallel to the center C2 of the squeegee roller 3 as the squeegee roller 3 rotates, and a portion of the ink 6 flows between the squeegee roller 3 and the doctor rod. Gap between 5 and 9
The ink layer 9 adheres to the outer circumferential surface of the squeegee roller 3 while being measured when passing through a, and the ink layer 9
form. The ink layer 9 is transferred to the contact area between the squeegee roller 3 and the cylindrical plate cylinder 20 as the squeegee roller 3 rotates, and adheres to the inner peripheral surface of the cylindrical plate cylinder 20 in the contact area.

The ink 6 thus supplied between the squeegee roller 3 and the plate cylinder 20 passes through the hole 1a of the metal cylindrical body 1 and the screen layer 2 due to the pressing force of the press roller 4 against the plate cylinder 20 side, and passes through the hole 1a and the screen layer 2 between the plate cylinder 20 and the stencil. It is supplied between the base papers 10, and a part of it further passes through the perforations of the stencil paper 10 and is transferred to the printing paper P side.

On the other hand, ink 6 remaining between the plate cylinder 20 and the stencil paper 10 without being transferred is transferred to the press roller 4 as the plate cylinder 20 rotates.
It is transferred to the region S2 where only the plate cylinder 20 contacts, and is returned into the plate cylinder 20 by the pressure of the press roller 4.

On the other hand, FIG. 3 is a partially exploded view of the outer circumferential surface of the plate cylinder 20, and a region S where the plate cylinder 20 and the press roller 4 are pressed against each other. In this embodiment, the center C3 of the press roller 4 is Since it is provided on the paper discharge side from the axis connecting the center C4 of the plate cylinder 20 and the center C2 of the squeegee roller 3, the area S1 where both the squeegee roller 3 and the press roller 4 are in contact with the plate cylinder 20 is
Compared to this, the contact area S of only the press roller 4 and the plate cylinder 20
2 is wide.

Therefore, the ink 6 supplied outside the plate cylinder in the S1 area is
Since the ink is recovered into the plate cylinder again at a high recovery rate in the wide contact area S2, even if the number of printed sheets increases, the amount of ink 6 between the plate cylinder 20 and the stencil paper 10 does not increase, and the formation of ink pools is prevented. be able to. Further, since the occurrence of ink pooling is prevented, the ink 6 can be prevented from spilling out at the end portion of the stencil paper 10.

(Effects of the Invention) As described above, in the stencil printing apparatus according to the present invention, the press roller is pressed against the plate cylinder on the paper discharge side from the axis passing through the center of the plate cylinder and the center of the squeegee roller. The contact area between the press roller and the plate cylinder, where ink is collected inside the plate cylinder, is wider than the contact area between the squeegee roller and the plate cylinder, where ink is supplied outside, and the ink supplied outside the plate cylinder is Since the ink is collected into the plate cylinder more efficiently than the other paper, there is no accumulation of ink between the plate cylinder and the stencil paper, and it is possible to obtain a stencil printing device in which ink does not run out at the end of the stencil paper. have an effect.

[Brief explanation of drawings]

Figure 1 is an overall configuration diagram of an embodiment to which the present invention is applied;
The drawings are an enlarged view of the main parts of FIG. 1, FIG. 3 is an explanatory diagram of the operation of an embodiment to which the present invention is applied, and FIG. 4 is a block diagram of the main parts of a conventional stencil printing apparatus. 3... Squeegee roller 4... Press roller 6... Ink 10... Stencil paper 20... Plate cylinder P... Printing paper C (... Center of plate cylinder C2... Squeegee roller Center of C3...Center of press roller!...Axis patent Applicant: Riso Kagaku Kogyo Co., Ltd. Agent: Patent attorney Kazu 1) Rule 1 Figure 1 (-11111)

Claims (1)

[Claims] 1. Comprising a cylindrical plate cylinder, a squeegee roller installed in the plate cylinder to supply ink to the inner circumferential surface of the plate cylinder, and a press roller arranged so as to be able to approach and separate from the outer circumferential surface of the plate cylinder. In the stencil printing apparatus, the stencil paper is wound around the cylindrical plate cylinder, and a press roller presses the printing paper against the stencil paper to print. A stencil printing device characterized in that a squeegee roller is brought into pressure contact with a plate cylinder on the paper discharge side with respect to an axis passing through the center of the squeegee roller.