JPH06135117A - Printer - Google Patents

Abstract

PURPOSE:To prevent ink from adhering to a side plate from an axial-direction end face of an ink supply roller opposed to the side plate or a peripheral surface of a doctor roller opposed to the side plate to previously prevent a contamination of the inside of a plate cylinder and the inside of a device with ink adhering to the side plate. CONSTITUTION:In an area from a position at which an ink supply roller 2A is opposed to a doctor roller 2B to a lower end of a side plate 3, a first recessed groove 3A is so formed as to have a shape sufficiently covering an axial- direction end face of the ink supply roller 2A and a thick ink film held on the roller 2A. In this construction, the axial-direction end face of the ink supply roller 2A is out of slide contact with the side plate 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing apparatus, and more particularly to an ink supply mechanism provided inside a plate cylinder.

[0002]

2. Description of the Related Art Conventionally, a stencil printing device has been known as one of printing devices, and this printing device winds a printing base paper, in which holes corresponding to an image are formed by plate making, on a plate cylinder having an ink passage structure. The structure is such that the ink is exuded from the inside of the plate cylinder to transfer the ink to the paper that is in close contact with the base paper. Further, in this printing apparatus, there is an ink supply apparatus having a structure shown in FIG. That is, this ink supply device is located inside the plate cylinder A in which an opening A1 is formed in a part of the peripheral wall and is arranged with a slight gap between it and the inner surface of the plate cylinder peripheral wall. Ink supply roller B
And a doctor roller C disposed with a slight gap for carrying ink between the ink supply roller B and the peripheral surface of the ink supply roller B, and ink formed by the ink supply roller B and the doctor roller C. It is provided with an ink supply pipe D for discharging ink toward the pool.

The ink supply roller B and the doctor roller C are both rotatably supported by an ink roller side plate E fixed to the ink supply pipe D, and the ink kneaded by the doctor roller C and the ink supply roller B are rotatably supported. The ink is supplied onto the ink supply roller B with a constant thickness through a gap between the two. Then, the ink carried on the ink supply roller B oozes from the perforated portion of the printing base paper F through the porous metal base of the plate cylinder and the screen layer, and is transferred to the printing paper.

By the way, the side plate E supporting the ink supply roller B and the doctor roller C has an end plate of the plate cylinder A in which the ink leached from between the inner peripheral surface of the plate cylinder A and the ink supply roller B. In order to prevent the ink supply roller B from leaking to the front side, a small gap is provided between the ink supply roller B and the axial end surface of the ink supply roller B to the extent that the rotation of the ink supply roller B is not hindered.

However, a small amount of ink is supplied from the ink supply roller B to the inner peripheral surface of the plate cylinder A in the gap between the axial end surface of the ink supply roller B and the facing surface of the side plate E. May enter, and the ink carried on the surface of the ink supply roller B may wrap around and enter, which causes a phenomenon that ink adheres to the axial end surface of the ink supply roller B. Occur.
Further, when the printing base paper is pressed against the plate cylinder A by the press roller G to exude ink from the inside of the plate cylinder,
By the pressing of the press roller G, the ink located between the inner peripheral surface of the plate cylinder A and the outer peripheral surface of the ink supply roller B is crushed, and the crushed ink erodes the axial end surface of the ink supply roller B. In some cases, it may come out. The ink adhering to the axial end surface of the ink supply roller B may be scattered inside the plate cylinder due to the structure of the side plate and may be contaminated inside the plate cylinder or leak out to the outside of the end plate of the plate cylinder. there were. That is, generally, in the case of a structure in which a part of the ink supply roller B in the circumferential direction is exposed from the lower edge of the side plate, as shown in FIG. On the ink recovery side corresponding to the position where the facing relationship with the peripheral surface ends, the axial end surface of the ink supply roller B and the side plate E.
The inks adhering to the axial end surface of the ink supply roller B are scraped off by the lower edge portion of the side plate E when the and the sliding contact start. Therefore, the ink scraped off at the lower edge of the side plate E and falling down is accumulated on the inner peripheral surface of the plate cylinder,
If the plate cylinder is scattered inside the plate cylinder due to the rotation of the plate cylinder or the accumulated amount is increased, it may reach the end plates of the plate cylinder and leak from the side plates.

Therefore, conventionally, in FIG. 6, a concave groove E is formed on the surface of the side plate facing the recovery side of the ink supply roller B.
1 is provided so that the sliding contact between the axial end surface of the ink supply roller B and the side plate E is reduced so that the lower edge of the side plate does not scrape the ink. There is proposed a structure in which the inclined surface E2 formed on the guide is directed toward the center of the ink reservoir (for example, Japanese Patent Publication No. 2-24667).

[0007]

However, at the position where the axial end surface of the ink supply roller and the side plate face each other and are in sliding contact, the ink supply roller B is the doctor roller C.
There is an ink supply side opposite to that where ink is supplied between the both rollers, and even at this position, the ink wraps around the axial end surface of the ink supply roller B. Therefore, at this position, the ink that has flowed around the axial end surface of the ink supply roller B is scraped off and adheres to the side plate E along the peripheral surface of the ink supply roller B, and adheres to the side plate E. When the accumulated amount of the deposited ink increases, as shown in FIG. 7, the ink drops from the lower edge of the side plate toward the peripheral surface of the plate cylinder to stain the inside of the plate cylinder or move toward the side plate of the plate cylinder. Therefore, such ink scattering becomes more noticeable as high-speed operation or as the ink supply film thickness increases, and not only from inside the plate cylinder but also from the joints of the side plates of the plate cylinder housing the ink supply mechanism. It may be taken out to contaminate the inside of the device.

Therefore, an object of the present invention is, in view of the above-mentioned problems in the conventional printing apparatus, from the axial end surface of the ink supply roller facing the side plate or the peripheral surface of the doctor roller facing the side plate to the side plate, respectively. It is an object of the present invention to provide a printing apparatus having a structure capable of preventing ink from adhering to the inside of the plate cylinder and the inside of the apparatus due to the ink adhering to the side plate.

[0009]

To achieve this object, the invention according to claim 1 is a rotatable porous cylindrical plate cylinder provided with a passage structure for ink supplied to the inner peripheral surface thereof, and A rotatable ink supply roller provided so as to be able to contact the inner peripheral surface of the cylindrical plate cylinder, and a rotatable doctor roller arranged with a slight gap set to the surface of the ink supply roller. , Rotatably supporting the ink supply roller and the doctor roller, and being provided in an axial end surface of the ink supply roller in a state in which the ink supply roller and the doctor roller are slidably contacted with the roller so as not to hinder the rotation of the ink supply roller. In a printing apparatus including an ink supply mechanism including a side plate that is provided with a side plate, the ink supply mechanism is provided in a range from a position where the ink supply roller and the doctor roller face each other to a lower edge portion of the side plate. A concave groove having a shape capable of covering the axial end surface of the supply roller and the film thickness of the ink carried on the roller is formed, and the axial end surface of the ink supply roller and the side plate are not in sliding contact with each other within the above range. It is characterized by being.

According to a second aspect of the present invention, the doctor roller is rotationally driven in the opposite direction to the ink supply roller, and the ink supply roller and the doctor roller are formed on the surface of the side plate facing the upper area of the doctor roller. With respect to the wedge-shaped ink fountain to be formed, a concave shape having an ink return portion having an inclined surface for guiding the ink from the position where the peripheral surface of the doctor roller and the side plate face each other on the center side of the ink fountain It is characterized by the provision of grooves.

[0011]

According to the present invention, the ink supply roller and the inner peripheral surface of the plate cylinder face each other in the rotational direction of the ink supply roller. Due to the presence of the concave grooves, a state where they do not slide against each other is set. Therefore, the ink that wraps around or oozes out to the axial end surface of the ink supply roller by sliding contact with the side plate is not scraped off or scraped off by the lower edge of the side plate. It becomes difficult for the ink to accumulate, and ink drops are prevented from falling.

Further, according to the present invention, when the doctor roller is driven to rotate, the ink adhered to the axial end surface of the doctor roller is prevented from coming into contact with the facing surface of the side plate and adhered to the axial end surface. The ink can be collected in the ink reservoir through the ink returning section which is continuous with the concave groove.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic view showing the structure of an ink supply mechanism which is a main part of the present invention. In the figure, an ink supply mechanism 2 provided inside the plate cylinder 1 includes an ink supply roller 2A, a doctor roller 2B, and an ink supply pipe 2C. Although the perforated portion of the plate cylinder 1 is omitted in FIG. 1, it is formed in the range in which the printing base paper is wound in the present embodiment as in the case shown in FIG. The ink supply roller 2A and the doctor roller 2B are rotatably supported by the side plate 3 attached to the ink supply pipe 2C. Of these rollers, the ink supply roller 2A is slightly different from the inner peripheral surface of the plate cylinder 1. A gap is set and arranged, and a drive mechanism (not shown) rotates in the same direction as the plate cylinder 1. Also,
The doctor roller 2B is arranged with a gap for ink application between the doctor roller 2B and the surface of the ink supply roller 2A,
An ink reservoir is formed in a wedge-shaped space formed at a portion where the doctor roller 2B and the ink supply roller 2A face each other.

In the ink supply unit 2, the ink supply pipe 2
The ink discharged from C is deposited in an ink reservoir formed at a position facing the ink supply roller 2A and the doctor roller 2B, and kneaded by both rollers, and then the ink supply roller 2A separates the ink from the plate cylinder 1. The kneaded ink is conveyed to the facing position.

On the other hand, on the side plate 3 that rotatably supports the ink supply roller 2A and the doctor roller 2C, the first and the first positions are provided at positions corresponding to the ink supply section and the ink recovery section in the rotation direction of the ink supply roller 2A. Two concave grooves 3A and 3B are formed. That is, as shown in FIGS. 1 and 2, the first recessed groove 3A is formed in a range from a position facing the doctor roller 2C in the rotation direction of the ink supply roller 2A to a lower edge portion of the side plate 3 in the ink supply roller. It has a size capable of covering a part of the axial end surface of 2A and the film thickness of the ink carried on the roller 2A, and is formed to have substantially the same curvature as the ink supply roller 2A. In addition, the second concave groove 3B is provided in the ink supply roller 2
A part of the axial end surface of the ink supply roller 2A and the roller 2A are provided in a range from a position facing the inner peripheral surface of the plate cylinder in the rotation direction of A to a wedge-shaped ink reservoir formed of a space formed by the doctor roller 2C. It has a size capable of covering the film thickness of the ink to be carried, and is formed by setting a portion having substantially the same curvature as the ink supply roller 2A.
The second concave groove 3B has a part in the forming direction, that is, a part close to the ink reservoir toward the central part in the axial direction of the ink supply roller 2A, and the inclined surface 3B1 in a direction in which the ink can be guided from the axial end surface. The ink moving in the ink collecting section is guided to the ink reservoir.

Next, the operation will be described. The ink from the ink reservoir formed by the ink supply roller 2A and the doctor roller 2C is carried on the peripheral surface of the ink supply roller 2A with a film thickness due to the gap set between the two rollers and moves. When the ink has adhered to the axial end surface of the ink supply roller 2A that has passed the position facing the doctor roller 2C, the ink faces the first recessed groove 3A of the side plate 3 so that the ink is supplied to the side plate 3. It will move without contact. Therefore, the ink attached to the axial end surface of the ink supply roller 2A moves without being scraped off by the surface of the side plate 3, and then reaches the ink recovery unit along the rotation direction of the ink supply roller 2A. In this ink collecting portion, the ink attached to the axial end surface of the ink supply roller 2A faces the lower edge portion of the side plate 3, but at this time, the ink is in the second concave groove 3B.
It can move in the recessed groove 3B without being scraped by the lower edge portion of the side plate 3, and is guided and collected in the ink reservoir while moving on the inclined surface 3B1.

According to this embodiment, the ink adhering to the axial end surface of the ink supply roller is not only scraped off by the lower edge of the side plate, but also scraped off by the surface of the side plate 3 on the ink supply side. Even if it occurs, it is possible to prevent the ink from adhering to the side plate.

By the way, in the above embodiment, with respect to the adhesion of the ink to the side plate, the object is to prevent the adhesion of the ink from the ink supply roller side to the side plate 3, but the present invention has such a structure. It is not limited.
For example, since the ink adheres to the side plate 3 even by the sliding contact between the doctor roller 2C and the side plate 3, it is possible to apply the case including this.

FIGS. 3 and 4 show a structure for preventing ink from adhering to the side plate 3 from the doctor roller 2C. In this case, the side plate 3 is provided with a third concave groove 3C. That is, in this case, the doctor roller 2
C is an ink supply roller 2 via a gear mechanism (not shown)
The doctor roller 2C is driven to rotate in the opposite direction to the direction A, and the side plate 3 facing the position passing the position facing the ink supply roller 2A in the rotation direction of the doctor roller 2C has a rotation direction of the doctor roller 2C. A concave groove 3C having a returning portion 3C1 having an inclined surface for guiding the ink toward the axial center side of the roller 2C is provided along the groove. The end portion of the returning portion 3C1 reaches the ink reservoir. In the structure described above, the ink that is about to adhere to the side plate surface facing the peripheral surface of the doctor row 2C enters the concave groove 3C by the rotation of the doctor roller 2C, and is not scraped off by the side plate 3 surface, and the return portion 3C1. And is guided to the ink reservoir by the movement of the inclined surface of the returning portion 3C1 to be collected.

In each of the above-mentioned examples, the structure for supplying the ink to the ink supply roller 2A by using the doctor roller 2C is used, but the structure for supplying the ink is as shown in FIG. , Ink supply roller 2A
It is also possible to use a structure in which the blade 5 and the holder 6 that holds one end of the blade 5 are arranged in an orientation that can set a wedge-shaped space formed by. In this case, since the ink supply roller 2A and the holder 6 are supported by the side plate 3, the side plate 3 is provided with the concave groove as in the above-described example.

[0022]

As described above, according to the present invention, the ink is provided on the side plate which is in sliding contact with the axial end surface of the ink supply roller, at the positions corresponding to the ink supply side and the ink recovery side in the rotation direction of the ink supply roller. Since the concave groove that does not come into sliding contact with the ink on the axial end surface of the supply roller is formed, the ink on the axial end surface of the ink supply roller is scraped off by the side plate surface or at the lower edge. It can be prevented from being scraped. Therefore, it is possible to prevent the situation where the ink deposited and adhered to the side plate falls, and it is possible to prevent the ink from scattering inside the plate cylinder or leaking from the plate cylinder single plate. . In addition, since the ink that tends to adhere to the side plate can be collected in the ink reservoir, the formation of ink lumps is prevented in advance, and the ink supply unevenness occurs when the lumps exist in the axial direction of the ink supply roller. It is possible to prevent uneven density by energizing the.

Further, according to the present invention, in addition to the above-mentioned ink supply portion and ink recovery portion, a concave groove is formed so that the ink does not contact the side plate even at the position where the doctor roller and the side plate face each other. As a result, it is possible to improve the efficiency of collecting the ink that tends to adhere to the side plate and prevent the above-mentioned adverse effects caused when the ink adheres to the side plate.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a main configuration of a printing apparatus according to the present invention.

FIG. 2 is a perspective view showing a part of the main part shown in FIG.

FIG. 3 is a schematic diagram showing a modification of the configuration of the main part shown in FIG.

FIG. 4 is a perspective view showing a part of the main part shown in FIG.

FIG. 5 is a schematic view showing a modified example of the ink supply mechanism.

FIG. 6 is a schematic diagram showing a conventional example relating to the structure of an ink supply mechanism in a printing apparatus.

FIG. 7 is a schematic diagram for explaining problems in the ink supply mechanism shown in FIG.

[Explanation of symbols]

 1 plate cylinder 2 ink supply mechanism 2A ink supply roller 2B doctor roller 3 side plate 3A first concave groove 3B second concave groove 3B1 inclined surface 3C third concave groove 3C1 return part

Claims (2)

[Claims] 1. A rotatable porous cylindrical plate cylinder having a structure for passing ink supplied to the inner peripheral surface thereof, and a rotatable ink supply provided so as to be in contact with the inner peripheral surface of the cylindrical plate cylinder. A roller, a rotatable doctor roller arranged with a slight clearance from the surface of the ink supply roller, the ink supply roller and the doctor roller rotatably supported, and the ink supply A printing apparatus having an ink supply mechanism, comprising a side plate provided on an axial end surface of the roller and arranged in sliding contact with the roller so as not to impede the rotation of the ink supply roller. In the range from the position where the supply roller and the doctor roller face each other to the lower edge of the side plate, the axial end surface of the ink supply roller and the ink film carried by the roller. A printing apparatus, characterized in that a recessed groove having a shape capable of covering the thickness is formed, and the axial end surface of the ink supply roller and the side plate are not in sliding contact with each other within the above range. 2. The printing apparatus according to claim 1, wherein the doctor roller is rotationally driven in a direction opposite to the ink supply roller, and the ink supply roller and the doctor are provided on the side plate surface facing the upper region of the doctor roller. An ink return portion having a slanted surface for guiding ink from a position where the peripheral surface of the doctor roller and the side plate face each other is formed on the central side of the ink reservoir formed by the roller and the ink reservoir. Printing device with a concave groove.