JP3188532B2 - Printing equipment - Google Patents

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 a structure for holding a printing base paper corresponding to a plate by a plate cylinder used in a stencil printing apparatus.

[0002]

2. Description of the Related Art Conventionally, a stencil printing apparatus is known as one of printing apparatuses. This printing apparatus is a printing cylinder having an ink passing structure for printing a printing base paper having a hole corresponding to an image formed by plate making. And a structure in which the ink is leached from the inside of the plate cylinder to transfer the ink to the paper in close contact with the base paper. ◆ Among the structures used for this printing, the structure of the main part includes the structure shown in FIG. ◆ That is, the printing apparatus includes a rotatable cylindrical plate cylinder B on which a printing base paper A corresponding to a perforated plate is wound, and a plate cylinder B.
A press roller C which can be brought into contact with and separated from the printing base paper wound on the printing drum, and an ink supply roller D which is located inside the plate cylinder B
1 is provided with an ink supply mechanism D for bringing the printer 1 into or near the inner peripheral surface of the plate cylinder.

In such a printing apparatus, one end of the printing base paper A in the longitudinal direction is clamped by a clamp mechanism E provided on the plate cylinder B, and the printing base paper A is adhered by ink oozing out of the plate cylinder B. Then, the printing base paper A is held on the surface of the plate cylinder B. When the paper is fed from a paper feed mechanism (not shown) and the paper confronts the press roller C, the press roller C comes into contact with the printing base paper A, so-called printing base paper A and the paper are brought into close contact, and the printing base paper Transfer the ink oozing from the paper onto the paper. In FIG. 5, reference numeral F denotes a peeling claw for peeling off the printing base paper A stuck to the surface of the plate cylinder B.

[0004]

By the way, the press roller C applies the printing base paper A to the surface of the plate cylinder B by a cam or a solenoid (not shown) which rotates in synchronization with the rotation of the plate cylinder B during printing. The contact time is determined when the clamping mechanism E on the plate cylinder B passes a position facing the press roller C. At this time, the press roller C is displaced at a high speed. And hits the surface of the plate cylinder B. Such high-speed displacement is performed in order to minimize the loss of a print image on a sheet of paper behind the clamp position of the printing sheet A.

Accordingly, such high-speed displacement of the press roller C causes a so-called collision when it comes into contact with the surface of the plate cylinder B, generating a loud impact sound or bouncing on the surface of the plate cylinder. This may induce a phenomenon such as the occurrence of density unevenness at the leading edge of the image on the paper.

Therefore, conventionally, there has been proposed a structure in which an impact absorbing member is provided at an initial pressing position on the plate cylinder side where the press roller comes into contact at the start of printing to avoid the above-mentioned problem.
(For example, JP-A-3-136890).

However, even when such an impact absorbing member is provided, it has not been possible to sufficiently prevent the impact sound and suppress the vibration of the press roller.

That is, in FIG. 5, the peeling claw F is provided between the surface of the plate cylinder B as much as possible to prevent the printed paper from sticking to the plate cylinder B and winding up with the rotation of the plate cylinder. It is desired to reduce the gap (the distance indicated by reference numeral S1 in FIG. 5) to approach the vicinity of the peripheral surface. However, if the shock absorbing member is arranged on a part of the peripheral surface of the plate cylinder, the shock absorbing member will protrude from the surface of the plate cylinder. You have to keep it away in the sense. Therefore, in order to make the tip of the peeling claw F as close as possible to the peripheral surface of the plate cylinder, the thickness of the shock absorbing member in the radial direction of the plate cylinder must be reduced as much as possible. As described above, when the thickness of the shock absorbing member is reduced, the buffering action is naturally reduced, and sufficient shock absorption cannot be performed.

In addition, a step occurs in the circumferential direction of the plate cylinder surface due to the thickness of the shock absorbing member located on the plate cylinder peripheral surface,
The pressing force when the press roller C passes through the step changes. When such a change in the pressing force occurs, unevenness occurs in the pressing force of the press roller, and, for example, the image density may become non-uniform without reaching a predetermined state.

Further, in order to prevent the generation of such an impact sound, it is conceivable that the displacement of the press roller is performed relatively gently. In this case, however, the displacement of the press roller until the press roller comes into contact with the plate cylinder surface is considered. During this time, the transfer of ink from the printing base paper to the paper must not be performed. Therefore, the circumferential length of the plate cylinder that moves before the press roller contacts the surface of the plate cylinder becomes longer as the displacement of the press roller becomes gentler, and the outer diameter of the plate cylinder itself increases accordingly. However, it cannot be denied that the printing apparatus becomes large.

In view of the above-mentioned problems in the conventional printing apparatus, it is an object of the present invention to prevent the occurrence of the impact noise and the bouncing phenomenon of the press roller with a simple configuration, and to reduce the density unevenness of the image. An object of the present invention is to provide a printing apparatus having a structure capable of preventing the printing apparatus from occurring.

[0012]

In order to achieve this object, the invention according to claim 1 is provided with a rotatable cylindrical porous plate cylinder, and rolls a perforated printing base paper on the cylindrical plate cylinder. ,
In a printing apparatus that performs printing by pressing a sheet against the cylindrical plate cylinder by a pressing member formed of a press roller, a superimposed portion is provided in a circumferential direction of the cylindrical plate cylinder, and one of the superposed portions is a fixed portion, The other is a movable portion that can be brought into contact with and separated from the fixed portion, and the printing base paper is sandwiched between the overlapping portions by a bending force generated when the movable portion is moved in a direction away from the fixed portion. Features.

According to a second aspect of the present invention, in the printing apparatus of the first aspect, a friction increasing means is provided at a position facing the printing base paper sandwiched between the overlapping portions of the cylindrical plate cylinder. And

According to a third aspect of the present invention, in the printing apparatus of the first aspect, the printing base paper is wound around a cylindrical plate cylinder after the leading end of the printing base paper is sandwiched with the leading end folded back to one of the overlapping portions. It is characterized by having become.

According to a fourth aspect of the present invention, in the printing apparatus of the first aspect, a peeling claw for peeling the printing base paper is disposed near the cylindrical plate cylinder, and the peeling claw is a cylindrical plate. It is characterized in that it is fixed in such a direction that a peeling posture can always be obtained with respect to the peripheral surface of the trunk.

[0016]

According to the present invention, there is no convex clamping mechanism on the peripheral surface of the cylindrical plate cylinder. That is, the leading end of the printing base paper is inserted into an open portion when the movable portion of the overlapped portion provided on the cylindrical plate cylinder is separated from the fixed portion, and the flexing force of the movable portion released from the opening is released. Between the fixed part. Therefore, since the leading end holding portion of the printing base paper on the peripheral surface of the cylindrical plate cylinder has a clamp structure in which a part of the circumferential direction of the plate cylinder can be opened and closed in the radial direction, a special convex portion is formed on the surface. Not done.

Further, according to the present invention, the printing base paper is pressed by the holding pressure at the holding position in response to the force in the direction of pulling the printing base paper generated when the press roller contacts the cylindrical plate cylinder during printing. Is prevented from coming off.

Further, according to the present invention, the holding portion of the printing base paper can be constituted by a part of the plate cylinder itself in the circumferential direction. Therefore, since there is no projecting member on the surface of the plate cylinder, the tip of the peeling claw used for peeling the printing base paper can be brought close to the peripheral surface of the plate cylinder, and the winding due to the sticking of the printing base paper is more effectively performed. Can be prevented.

[0019]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.

FIG. 1 is a schematic view showing the structure of a main part of the present invention. In FIG. 1, although the details of the plate cylinder 1 are not shown, the plate cylinder 1 is located in a range corresponding to a printing base paper winding section in the circumferential direction. A metal plate having a large number of holes and an ink passage portion as a base, and a cylindrical member that can rotate normally and reversely, having an ink transmission structure in which a screen layer using, for example, polyester fiber is arranged on the outer surface thereof. The overlapping portion 1A is provided in a part of the circumferential direction. ◆ The overlapping portion 1A is a configuration which is a feature of the present embodiment. The overlapping portion 1A divides the peripheral wall of the plate cylinder 1 and
1 is positioned on the circumference of the forme cylinder 1 with the regular diameter, and the other one 1A2 is made longer in circumference than the split position and has the same diameter as the diameter of the forme cylinder 1
The tip is located inside A1. ◆ Therefore, the other divided 1A2 is the divided one 1A.
Since the diameter is reduced at the position facing 1
The bending force for returning to the normal diameter is accumulated. In addition, the other 1A2 is divided into one by the bending force.
This means that the child is given a habit of sticking to the inside of A1.

On the other hand, an ink supply unit 2 is disposed inside the plate cylinder 1, and the ink supply unit 2 approaches or contacts the inner peripheral surface of the plate cylinder 1 and is capable of interlocking with the plate cylinder 1. The supply roller 2A and the doctor roller 2B fixed closely to the ink supply roller 2A with a predetermined gap.
And In the ink supply unit 2, for example, ink ejected from an ink supply pipe 2C provided on a support shaft of the plate cylinder 1 is accumulated in an ink reservoir formed at a position facing the ink supply roller 2A and the doctor roller 2B. After being kneaded by these two rollers, the ink supply roller 2A conveys the kneaded ink to a position where the ink drum 2 and the plate cylinder 1 face each other.

In the vicinity of the peripheral surface of the plate cylinder 1, a press roller 3 is disposed at a position facing the ink supply roller 2A with the plate cylinder 1 interposed therebetween, and a peeling claw 4 is disposed behind the press roller 3. Have been. In the press roller 3, since the clamp portion of the printing base paper is constituted by the peripheral surface of the plate cylinder,
A slight stroke with respect to the surface of the plate cylinder 1 (symbol S in the figure)
(Distance indicated by) is set and provided so that it can come and go,
When it is not opposed to the perforated area of the plate cylinder 1, it is separated from the plate cylinder 1, and when it is opposed to the perforated area, it moves toward the plate cylinder 1 and presses the paper against the plate cylinder 1. You can do it. The contact / separation stroke S of the press roller 3 described above is smaller than the conventional contact / separation stroke S1 shown in FIG. 5 because there is no projecting member on the peripheral surface of the plate cylinder. The peeling claw 4 is fixed with its tip positioned at a position separated from the peripheral surface of the plate cylinder 1 by a predetermined gap. The predetermined gap is an extremely small gap in consideration of the fact that there is no member corresponding to the clamp mechanism E shown in FIG.

In FIG. 2, at a position facing the plate cylinder 1,
A vacuum device 6 is provided at a position where the printing base paper 5 is fed from a plate making device (not shown). The vacuum device 6 has a suction unit 6A that can be moved up and down in the figure.
When A is located, it descends and sucks one 1A1 of the overlapping portion 1A to ascend.

Next, the operation will be described. At the time of plate feeding to the plate cylinder 1, the overlapping portion 1A of the plate cylinder 1 faces the position where the printing base paper is fed from the plate making device. Then, in this state, the suction unit 6A of the vacuum device 6 descends, and rises while sucking one of the overlapping units 1A. Therefore, in the overlapping portion 1A, the side that is sucked by the vacuum device 6 is a movable portion, and the other side opposite to this is a fixed portion, and the movable portion is separated from the fixed portion by the vacuum device 6. Thus, as shown in FIG.
A space is formed to sandwich the leading end of the printing base paper 5.

Then, the vacuum device 6 is used for the printing base paper 5.
While a predetermined amount is fed out, the lowering position is maintained, the suction is released, and the suction is released. The movable portion corresponding to one 1A1 of the overlapping portion 1A is brought into close contact with the fixed portion corresponding to the other 1A2 for printing. The leading end of the paper 5 is clamped. In addition, the vacuum device 6 releases suction at the raised position, especially when the rising stroke is small, instead of descending, and accumulates the bending force when one of the overlapping portions 1A is opened. It may be used to make it adhere to the other 1A2.

When the leading end of the printing base paper 5 is clamped in this way, for example, the end of the clamping is determined based on the detection result of the feeding amount of the printing base paper 5, and the plate cylinder 1 starts rotating at this time. Therefore, the unfolded portion of the printing base paper 5 until it is cut by the plate making device is adhered by the ink oozing on the plate cylinder surface, and is held on the plate cylinder surface.

When the plate feeding operation is completed, a sheet is fed from a sheet feeding device (not shown) in synchronization with the end time, and the press roller 3 moves toward the surface of the plate cylinder 1 at this time. The paper and the printing base paper 4 are pressed.

Further, the sheet passing through the press roller 3 is peeled off from the peripheral surface of the plate cylinder by the peeling claw 4.

According to the present embodiment, the clamp portion of the printing base paper 5 can be constituted by the peripheral portion of the plate cylinder 1.
It is possible to eliminate members such as holding pieces protruding from the peripheral surface of the plate cylinder, thereby making it possible to make the leading end of the peeling claw 4 close to the vicinity of the plate cylinder to reliably prevent the sheet from winding up. In addition, since there is no member that interferes with the tip of the peeling claw, a fixed structure can be provided, thereby simplifying the structure.

As a means for separating the movable portion in the overlapping portion from the fixed portion and forming a space for sandwiching the leading end of the printing base paper, the configuration shown in FIG. 3 can be employed. The configuration shown in FIG. 3 is based on the assumption that the other side 1A2 shown in FIG. 1, that is, the portion located inside the one side 1A1 located on the diameter of the peripheral wall is a movable part (hereinafter, for convenience, the fixed part is The movable portion is indicated by reference numeral 1A20, and the movable portion is denoted by reference numeral 1A20). By pressing the movable portion 1A20 inward, a space for holding the printing base paper is secured. For this reason, in the case of the example shown in FIG. 3, instead of the vacuum device 6 shown in FIG. 2, an operating member 7 provided so as to be able to advance and retreat along a direction in which the movable portion 1A20 can be pushed in is arranged. I have. Therefore, the operating member 7 is displaced in the direction of pushing the movable portion 1A20 toward the inside of the plate cylinder 1 at the same operation timing as the vacuum device 6 shown in FIG.
0 is separated from the fixed portion 1A10, and when the leading end of the printing base paper is completed, the movable portion 1A20 is displaced outward from the plate cylinder 1 and is brought into close contact with the fixed portion 1A10.

The printing base paper, the leading end of which is sandwiched by the overlapping portion 1A, rotates with the rotation of the plate cylinder 1. When the press roller 3 is in contact with the plate cylinder 1, the pressure is applied by the press roller 3. More or less, it receives a force in the direction of being pulled out of the clamp portion constituted by the overlapping portion 1A.
Therefore, in this embodiment, in order to prevent the printing base paper 5 from coming off due to such a force from the press roller 3,
It is also possible to employ friction increasing means for increasing the frictional coupling in the above-mentioned overlapping portion 1A. ◆ That is, as the friction increasing means, for example, there is a structure in which a rubber plate or a sandpaper having a high friction coefficient is attached to the overlapped portion, or furthermore, a large number of fine projections are formed. For example, when the printing base paper 5 has a configuration in which a film is laminated on a base material, such a friction increasing unit is provided with the friction increasing unit on the surface facing the film surface in the overlapped portion, so that the printing base paper 5 It is possible to improve the frictional connection with the overlapping portion.

As a method of preventing the printing base paper from slipping off, for example, as shown in FIG. 4, the configuration of the front end 5A of the printing base paper 5 is such that the front end 5A is connected to one side 1A of the overlapping portion 1A.
It may be folded back at one end and arranged between the other overlapping portion 1A2 of the overlapping portion 1A1 located inside.

[0033]

As described above, according to the present invention, the leading end holding portion of the printing base paper can be constituted by the peripheral wall of the plate cylinder. That is, by forming a overlapped portion by dividing a part of the peripheral wall, the leading end of the printing base paper can be sandwiched between the overlapped portions. Therefore, part of the peripheral wall of the plate cylinder
Since it is configured as a conventionally used clamp mechanism, the clamping mechanism for the printing base paper can have an extremely simple structure. Moreover, since the conventional clamping mechanism or the like does not exist on the peripheral surface of the plate cylinder, the press roller and the peeling claw can be brought closer to the plate cylinder side because interference with this mechanism does not occur. Therefore, the impact noise can be reduced by reducing the contacting / separating stroke of the press roller, and the bump of the press roller can be prevented by eliminating the step from the peripheral surface of the plate cylinder in conjunction with the stroke phenomenon. Therefore, it is possible to prevent the occurrence of unevenness in image density and obtain stable image characteristics.

Further, according to the present invention, the provision of the friction increasing means in the above-mentioned overlapping section or the constitution in which the printing base paper is folded back in the overlapping section prevents the printing base paper from slipping out. Can be
This makes it possible to prevent the occurrence of printing failure.

According to the present invention, the tip of the peeling claw facing the plate cylinder can be made extremely close by eliminating the clamp mechanism protruding from the peripheral surface of the plate cylinder. Since it can be fixed at the position, the structure of the structure can be simplified by eliminating the use of the contact / separation mechanism conventionally used.

[Brief description of the drawings]

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

FIG. 2 is a schematic diagram showing a configuration for forming a space for sandwiching printing base paper used in the main configuration shown in FIG. 1;

FIG. 3 is a schematic diagram showing a modification of the configuration for forming a space for sandwiching the printing paper shown in FIG. 2;

FIG. 4 is a schematic view showing a structure for preventing a printing base paper from slipping off in a printing apparatus according to the present invention.

FIG. 5 is a schematic diagram showing a conventional example around a plate body in a printing apparatus.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 plate cylinder 1A overlapping portion 1A1 fixed portion composed of one of divided overlapping portions 1A2 movable portion composed of the other of the divided overlapping portions 3 press roller 4 peeling claw 5 printing paper 6 vacuum device 7 operating member

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int. Cl. ⁷ , DB name) B41L 13/04 B41L 13/14 B41F 27/00-27/12

Claims (4)

(57) [Claims] 1. A printing machine comprising a rotatable cylindrical porous plate cylinder, a printing base paper perforated in said cylindrical plate cylinder is wound, and a sheet is pressed against said cylindrical plate cylinder by a pressing member comprising a press roller. In a printing apparatus that performs printing according to, the overlapping portion is provided in the circumferential direction of the cylindrical plate cylinder, one of the overlapping portions is a fixed portion, and the other is a movable portion that can be moved toward and away from the fixed portion, A printing apparatus, wherein a printing base paper is sandwiched between overlapping portions by a bending force generated when a movable portion is moved away from a fixed portion. 2. The printing apparatus according to claim 1, wherein friction increasing means is provided at a position facing the printing base paper sandwiched between the overlapping portions of the cylindrical plate cylinder. 3. The printing apparatus according to claim 1, wherein the printing base paper is sandwiched in a state where the leading end thereof is folded back to one of the overlapping portions, and then wound around a cylindrical plate cylinder. Printing device. 4. A printing apparatus according to claim 1, wherein a peeling claw for peeling the printing base paper is disposed near the cylindrical plate cylinder, and the peeling claw is arranged on the peripheral surface of the cylindrical plate cylinder. The printing device is fixed in a direction that always gives a peeling posture.