JP2006167957A - Stencil printing equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a stencil printing equipment, with which a tail end leakage phenomenon can be favorably suppressed over a long period of time. <P>SOLUTION: Apart from the original clamper for clamping the tip of a master, a clamper 50 for a rear end side, which presses the rear end of the master in its windingly mounting direction against the outer peripheral surface of a printing drum 1 (strictly, a porous cylindrical support 51), is provided. The clamper 50 for the rear end side has a clamper main body 57, a supporting member 58 for supporting and a spring member (not shown) for pressing the clamper main body 57 against the porous cylindrical support 51. The clamper main body 57 has a length so long as to extend to the opening region of the porous cylindrical support 51 and presses the rear end 2A of the master 2 in its windingly mounting direction against the outer peripheral surface of the porous cylindrical support 51 over its opening region, resulting in damming up the movement of ink to the rear end side of the master. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a stencil printing apparatus that winds a master plate on the outer peripheral surface of a printing drum and presses a sheet-like recording medium with pressing means such as a press roller to perform printing.

  In the stencil printing apparatus, the stencil printing base paper (hereinafter simply referred to as “master”) having a thermoplastic resin film and a porous support is used to perform perforation plate making based on image information by the heating element of the thermal head. The pre-printed master is transported and wound around the outer peripheral surface of a printing drum as a porous cylindrical support composed of a porous support and a mesh-like screen member made of resin or metal mesh, and ink is supplied While the ink is supplied from the inner peripheral surface of the printing drum by the means, the printing paper as the sheet-like recording medium is continuously pressed against the master by the pressing means such as a press roller, and the opening portion (opening portion of the printing drum) ), Ink is oozed from the perforated part of the master and printing is performed.

The ink supplied from the inside of the printing drum is consumed by the master being pressed by a press roller or the like through the printing paper, and oozing out from the opening of the printing drum and the punching of the master and transferred to the printing paper. However, in the non-perforated portion (non-plate making portion) of the master, it is accumulated as excess ink between the outer peripheral surface of the printing drum and the master.
When printing is continued for a long time in this state, the ink accumulated between the outer peripheral surface of the printing drum and the master is repeatedly compressed by the pressing of the press roller, so that the tail end side (the trailing end in the winding direction) of the master is compressed. To the side).
Finally, there is a problem that the ink leaks from the tail end of the master, that is, a so-called “butt leak” phenomenon, and the inside of the apparatus is soiled. Further, there is a problem that the leaked ink adheres to the printing paper and causes printing failure.

In order to prevent such ink leakage, Japanese Patent Publication No. 60-028670 discloses a stencil printing apparatus in which a weir element made of an ink impermeable material is disposed between a porous cylindrical support and a screen layer. Has been.
In this stencil printing apparatus, the printing part (printing pressure part) defined between the printing drum and the press roller reaches the tail part of the master, and is pressed between the printing drum and the press roller at the unperforated part of the master. As a result, the ink is pressed between the ink supply roller inside the printing drum and the press roller through the non-perforated master portion, and is sequentially fed toward the dam element side toward the back of the master winding direction. And reach the weir element.
When the printing drum further rotates, the press roller lightly rides on the portion where the master is raised by the dam element, and pushes the ink reaching the dam element back toward the inside of the printing drum.
In this way, a small amount of excess ink generated every rotation of the printing drum is pushed back into the printing drum each time, so that the ink flows backward and is prevented from leaking from the tail end of the master.

Japanese Patent Publication No. 60-028670 JP 2001-105710 A

However, in the above-described conventional configuration, the master is pushed up in the radial direction of the printing drum by the weir element, so that a gap to be called an ink storage space is formed between the printing drum and the master before and after the master winding direction of the weir element. . When ink accumulates in this gap and the pressure increases over time, the ink moves between the master and the weir element, which are simply in contact, and eventually leaks.
That is, in the short term, the damming function can be obtained by forming the ink storage space by the dam element, but in the long term, the function disappears and there is still a problem that the bottom leaks.

  An object of the present invention is to provide a stencil printing apparatus that can satisfactorily suppress the tail leakage phenomenon over a long period of time.

  In order to achieve the above object, according to the first aspect of the present invention, an outer peripheral surface of a printing drum having a perforated region that allows ink to pass through and a non-perforated region that does not allow ink to pass through the peripheral surface. Printing is performed by sandwiching and winding the leading end of the master that has been made with a provided clamper, and pressing the sheet-like recording medium against the printing drum by pressing means to transfer the ink supplied from the inside of the printing drum. In the stencil printing apparatus, a rear end side clamper is provided on the outer peripheral surface of the printing drum, and presses the rear end portion in the winding direction of the master against the outer peripheral surface of the printing drum on the opening area. It is characterized by being.

In invention of Claim 2, in the stencil printing apparatus of Claim 1,
The rear end side clamper has a flat clamper main body and a support member that rotatably supports the clamper main body, and the front end side of the clamper main body has a shape protruding toward the outer peripheral surface side of the printing drum. It is characterized by having.

  According to a third aspect of the present invention, in the stencil printing apparatus according to the first or second aspect, the rear end side clamper is pressed by a biasing force of a spring member.

  According to a fourth aspect of the present invention, in the stencil printing apparatus of the first or second aspect, the rear end side clamper is pressed by a magnetic attraction force.

  According to a fifth aspect of the present invention, in the stencil printing apparatus according to any one of the first to fourth aspects, the rear end side clamper is rotatable about 180 ° on the outer peripheral surface of the printing drum. It is characterized by.

  According to a sixth aspect of the present invention, in the stencil printing apparatus according to the fifth aspect, when the rear end side clamper is tilted in a direction not to press the master, the stencil printing apparatus is tilted by a biasing force of a spring member or a magnetic attractive force. It is retained.

  According to the first aspect of the present invention, plate making is performed by the clamper provided on the outer peripheral surface of the printing drum having the perforated region that allows ink to pass through and the non-perforated region that does not allow ink to pass through the peripheral surface. In a stencil printing apparatus that performs printing by sandwiching and winding the tip of a finished master, pressing a sheet-like recording medium against a printing drum by a pressing means, and transferring ink supplied from the inside of the printing drum, Since it has a rear end side clamper that is provided on the outer peripheral surface of the printing drum and presses the winding direction rear end portion of the master on the outer peripheral surface of the printing drum on the opening area, The passage of the ink to the master rear end portion can be strongly blocked and collected into the inside of the printing drum, so that the ink leakage can be suppressed with high accuracy.

  According to a second aspect of the present invention, in the stencil printing apparatus according to the first aspect, the rear end side clamper includes a flat clamper body and a support member that rotatably supports the clamper body. Since the front end side of the clamper body has a shape protruding toward the outer peripheral surface side of the printing drum, the damming function can be further enhanced.

  According to a third aspect of the present invention, in the stencil printing apparatus according to the first or second aspect, since the rear end side clamper is pressed by the biasing force of the spring member, a simple and low cost configuration is provided. Thus, a damming function can be obtained.

  According to a fourth aspect of the present invention, in the stencil printing apparatus according to the first or second aspect, since the pressing of the rear end side clamper is performed by a magnetic attractive force, a simple and low-cost configuration is provided. A damming function can be obtained.

  According to a fifth aspect of the present invention, in the stencil printing apparatus according to any one of the first to fourth aspects, the rear end side clamper is rotatable about 180 ° on the outer peripheral surface of the printing drum. Since there is something, the open state of the clamper can be kept stable.

  According to a sixth aspect of the present invention, in the stencil printing apparatus according to the fifth aspect, when the rear end side clamper is tilted in a direction not to press the master, it is tilted by the biasing force or magnetic attraction force of the spring member. Since it is held at the position, the open state of the clamper can be kept stable with a simple configuration.

Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.
First, the configuration of the stencil printing apparatus and the outline of the printing operation in this embodiment will be described with reference to FIG.
A master roll 10 is rotatably held in the plate making unit 19. The master 2 fed out from the roll state is pressed against the heating element of the thermal head 17 by the platen roller 9 and conveyed while being punched in accordance with an original pattern (image information) read by a scanner (not shown) or image information input from the outside. Is done.
When the master-making master 2 reaches a predetermined length, it is cut by the cutter unit 4 and conveyed by a plate-feeding roller pair 5 toward a clamper 12 provided on the outer peripheral surface of the printing drum 1.

At this time, the printing drum 1 is stopped and the clamper 12 is opened by an unillustrated opening / closing device. When it is determined that the leading end of the master 2 has reached the clamper 12, the opening / closing device operates to close the clamper 12, and the leading end of the master 2 is clamped. The clamper 12 has a known configuration in which the tip of the master 2 is clamped by a rotatable clamper body on a stage having a flat surface.
When the leading end of the master 2 is clamped, the printing drum 1 is rotated clockwise by a driving device (not shown), and the master 2 is wound around the outer peripheral surface of the printing drum 1.
Prior to the plate feeding step, the used master 2 is peeled off from the outer peripheral surface of the printing drum 1 by the plate discharging unit 18 and discharged.

The printing drum 1 includes a porous cylindrical support body (plate cylinder) made of stainless steel having an open area where many fine holes are present and a non-open area where there are no open holes, and the porous cylindrical support body. It is comprised from the mesh screen layer wound around the outer peripheral surface.
Inside the printing drum 1, there are provided an ink roller 13 that rotates in synchronization with the same direction as the printing drum 1, and a doctor roller 15 that is arranged slightly spaced from the outer peripheral surface of the ink roller 13. A wedge-shaped facing space formed between the ink roller 13 and the doctor roller 15 forms an ink reservoir 16.
The ink reservoir 16 stores ink dripped from a hole (not shown) of the ink supply pipe 11 that also serves as the rotation support shaft of the printing drum 1.
The ink 14 in the ink reservoir 16 is supplied to the outer peripheral surface of the ink roller 13 by the rotation of the ink roller 13 and the doctor roller 15. The ink supplied to the outer peripheral surface of the ink roller 13 is supplied to the inner peripheral surface of the printing drum 1.

Below the printing drum 1, an impression cylinder 20 is disposed as a pressing unit at a position facing the ink roller 13.
The impression cylinder 20 is a printing sheet 3 serving as a sheet-like recording medium on a master 2 wound around the outer circumferential surface of the printing drum 1 at a printing pressure portion that is a position on the outer circumferential surface of the printing drum 1 facing the ink roller 13. It is a pressing means that presses a roller-shaped rotating body.
The impression cylinder 20 is rotatably supported by a shaft 23 on a pair of arms 25 supported on one end side by a shaft 24 and rotatably provided in the vertical direction, and provided on the other end side of the arm 25. The spring 26 is pressed against the printing drum 1 by the urging force.
As the pressing means, a press roller may be used in addition to the impression cylinder 20. In the following example, the case of the impression cylinder 20 will be described.

  The impression cylinder 20 is configured to have a flat part on the outer periphery in order to avoid collision with the clamper 12 on the printing drum 1 and a rear end side clamper 50 to be described later, and has a D-shape when viewed from the axial direction. ing. The flat portion is provided with a gripper 21 for holding the leading end portion of the printing paper 3 so as to be freely opened and closed. The gripping claw 21 is opened at a predetermined timing by a cam (not shown), is closed after the printing paper 3 is added, holds the printing paper 3 on the impression cylinder 20, and when printing is finished, a drain provided near the outer periphery of the impression cylinder 20. The paper nail 29 is reopened at the site of the paper nail 29, and the front end of the print paper 3 is opened to send the front end of the print paper 3 to the paper discharge transport device 35 via the paper discharge nail 29.

On the downstream side (left side) of the impression cylinder 20 in the transport direction, a paper discharge claw 29 for peeling the print paper 3, and a paper discharge transport device 35 for sucking and transporting the peeled print paper 3 by the negative pressure action of air, A paper discharge stand 36 on which the printing paper 3 conveyed by the paper discharge conveying device 35 is discharged and stacked is provided.
On the upstream side (right side) of the impression cylinder 20 in the conveyance direction, a printing paper storage unit including an elevator-type paper feed base 31 that can store printing papers 3 of different sizes is provided. The paper feed tray 31 is provided with sensors 40 and 41 as size detection means for detecting the size of the stored printing paper 3. The sensor 40 is arranged at a position where the leading edge of the printing paper 3 can be detected, and the sensor 41 is arranged behind the sensor 40 at a predetermined interval in the transport direction.

Only the sensor 40 can detect the size of the print paper 3 accommodated when the presence of the print paper 3 is detected and when the sensor 40 and the sensor 41 detect it.
The paper feed table 31 is moved up and down while being held so as to obtain an appropriate pressing force that allows the uppermost printing paper 3 stacked by a driving device (not shown) to be always conveyed to the calling roller 30. Yes.
The printing paper 3 drawn out by the calling roller 30 is separated by the paper feeding roller 32 and the separation roller 34, and only the uppermost printing paper 3 is fed. The fed printing paper 3 passes through the guide plate 38 and reaches the registration roller pair 33, where the printing paper 3 is temporarily stopped to correct the oblique deviation, and then the mark formed by the printing drum 1 and the impression cylinder 20 at a predetermined timing. It is sent to the pressure part.

Next, the significance and configuration of the rear end side clamper 50 will be described.
Before that, the “butt leakage” phenomenon in the conventional configuration will be schematically described based on FIG. 7 (linear development view). In FIG. 7, reference numeral 51 denotes a porous cylindrical support, 52 denotes a screen layer, 53 denotes a press roller, 54 denotes a mylar (trade name) as a countermeasure against tail leakage, and 55 denotes ink.
The porous cylindrical support (plate cylinder) 51 has an open area (opening) in which a large number of minute holes 51a are formed, and a non-opening area (non-opening) in which no holes 51a are present. The clamper 12 is provided in the non-opening region.
The master 2 has a thickness of about 50 μm, and the screen layer 52 has a thickness of 150 to 200 μm.

The ink 55 </ b> A supplied to the ink roller 13 inside the printing drum 1 passes through the hole 51 a of the porous cylindrical support 51 by the printing pressure action by pressing of the press roller 53, and the porous cylindrical support 51 and the master. 2 moves to the ink reservoir 56 between the two.
On the other hand, there is also a behavior in which the ink 55B that already exists in the ink reservoir 56 moves from the hole 51a of the porous cylindrical support 51 to the inside of the porous cylindrical support 51 by the printing pressure action and is recovered. . Further, the ink 55C supplied to or existing in the ink reservoir 56 is transferred to the printing paper 3 through the screen layer 52 and the perforations 2a of the master 2 by the printing pressure action.

Here, the master 2 shows a case where the number of perforations 2a is small (the number of images is small). When printing is performed continuously for a long time using such a master 2, the surplus ink 55 </ b> D is accumulated in the ink reservoir 56 between the porous cylindrical support 51 and the master 2.
Such excess ink 55 </ b> D is repeatedly compressed by being pressed by the press roller 53, thereby being pushed to the rear end side (tail end side) of the master 2. In this case, when the rear end side of the master 2 of the ink reservoir 56 is dammed by the mylar 54, a part of the surplus ink 55 </ b> D is collected into the porous cylindrical support 51, but a part of the mylar 54 is used. Move by pushing and reach the tail end of Master 2. As a result, there is a concern that ink leaks.

The present embodiment aims to suppress such a tail leakage phenomenon, and a rear end side clamper 50 is provided as shown in FIG. The rear end side clamper 50 is a flat clamper main body 57, a support member 58 that supports the clamper main body 57 so as to be rotatable by about 180 °, and the clamper main body 57 that presses the porous cylindrical support 51. It has a spring member that does not.
The support member 58 is actually provided on a well-known stage (not shown) in the non-opening region of the porous cylindrical support 51 in the same manner as the clamper 12.
The clamper main body 57 has a length that extends to the aperture region, and the winding direction rear end 2A of the master 2 is placed on the outer peripheral surface of the porous cylindrical support 51 on the aperture region (in a broad sense, the printing drum 1). To the outer peripheral surface).

At the front end portion of the clamper body 57, the rear end portion 2A of the master 2 is pressed by the biasing force (closing force) F of the spring member, and the rear end side of the ink storage portion 56 is substantially constricted at an acute angle. It will be in a state of being dammed up.
Even if the excess ink 55D is accumulated in the ink reservoir 56 and repeatedly compressed, it is recovered into the porous cylindrical support 51.
Since the clamper 12 is merely a stopper for winding the master 2 around the outer peripheral surface of the printing drum 1, the front end of the master 2 may be simply clamped, but the rear end side clamper 50 achieves the above-mentioned purpose. Therefore, the rear end 2A of the master 2 is pressed against the outer peripheral surface of the porous cylindrical support 51, and both are functionally different.

In order to improve the damming function by pressing the clamper main body 57, in this embodiment, the clamper main body 57 is set to press the rear end portion 2A of the master 2 with an inclination of θ ° below the horizontal plane, The pressing force is concentrated on the lower corner portion 57 a at the tip of the clamper body 57.
The rear end side clamper 50 is opened and closed at a predetermined position by an opening / closing device (not shown). As shown in FIG. 3, the opening / closing device has a motor unit 60 that moves up and down. The motor unit 60 includes a stepping motor 61 and a drive gear 62 fixed to the rotation shaft of the stepping motor 61. A driven gear 63 that meshes with the drive gear 62 is fixed to the end of the rotation shaft 57 b of the clamper body 57.
When the clamper body 57 is closed, the drive gear 62 and the driven gear 63 are separated. When the clamper body 57 is opened, the motor unit 60 is lowered and the drive gear 62 and the driven gear 63 are engaged, and the stepping motor 61 is controlled by a control means (not shown) to open the clamper body 57 to a predetermined position. The motor unit 60 may be moved in the horizontal direction so that the drive gear 62 and the driven gear 63 are engaged with each other.

The opening / closing timing of the clamper 12 and the rear end side clamper 50 will be described with reference to FIG.
FIG. 4A shows a state where the master 2 is wound around the printing drum 1. In this state, both the clamper 12 and the rear end side clamper 50 are closed.
At the time of discharging the plate, as shown in FIG. 4B, the clamper 12 opens at a predetermined timing at a predetermined rotation position of the printing drum 1, and the released front end portion of the master 2 is nipped by the plate discharging unit 18 and peeled off. . At this time, in the rear end side clamper 50, the clamper main body 57 is rotated by approximately 180 ° and tilted to the opposite side. The urging force of the spring member is similarly generated on the opposite side, and the clamper main body 57 is stably held at the collapsed position.

When the plate removal is completed, as shown in FIG. 4C, the clamper 12 is opened at a predetermined timing, and the master 2 that has been subjected to plate making is conveyed. At this time, in the rear end side clamper 50, the clamper body 57 is held in a collapsed state.
When the clamper 12 clamps the leading end of the master 2 and the process of winding the master 2 around the outer peripheral surface of the printing drum 1 as the printing drum 1 rotates, the rear end side clamper 50 is moved at a predetermined timing. The clamper main body 57 is raised from a fallen state and is rotated by approximately 180 °, and the rear end 2A of the master 2 is pressed against the outer peripheral surface of the printing drum 1.

A second embodiment will be described with reference to FIG. Note that the same parts as those in the above embodiment are denoted by the same reference numerals, and unless otherwise specified, description of the configuration and functions already described is omitted, and only the main part will be described (the same applies to other embodiments below).
The rear end side clamper 64 in the present embodiment includes a stage 65 made of a magnet material fixed on the outer peripheral surface of the non-opening region of the printing drum 1, a clamper body 66, and a support member 67.
The clamper main body 66 is made of a magnetic material, and the clamper main body 66 is held in the open position that is tilted to the opposite side of the master pressing position (closed position) by the magnetic attractive force between the clamper main body 66 and the stage 65. The
A convex portion 68 made of a magnet material that protrudes toward the outer peripheral surface of the printing drum 1 at the closed position is integrally provided at the tip of the clamper body 66.

The printing drum 1 (strictly, the porous cylindrical support 51) is formed of a magnetic material. When the printing drum 1 is in the closed position, the clamper main body 66 has a magnetic attraction force and a convex portion between the clamper main body 66 and the stage 65. The rear end 2 </ b> A (not shown in FIG. 5) of the master 2 is pressed against the outer peripheral surface of the printing drum 1 by the magnetic attractive force between the printing drum 68 and the printing drum 1.
In this case, the rear end portion 2A of the master 2 is locally pressed by the convex portion 68, and a high damming function is obtained.

FIG. 6 shows a third embodiment. The rear end side clamper 70 in this embodiment includes a stage 65 made of a magnet material fixed on the outer peripheral surface of the non-opening region of the printing drum 1, a clamper body 71, and a support member 67.
The clamper main body 71 is made of a magnetic material, and the clamper main body 71 is held in the open position, which is tilted opposite to the master pressing position (closed position), by the magnetic attraction between the clamper main body 71 and the stage 65. The
The clamper body 71 is formed in a Z-shaped step shape, and a magnet portion 72 is integrally provided at the tip thereof.
The printing drum 1 (strictly, the porous cylindrical support 51) is formed of a magnetic material. When the printing drum 1 is in the closed position, the clamper main body 71 has a magnetic attraction force between the clamper main body 71 and the stage 65 and a magnet portion. The rear end 2 </ b> A (not shown in FIG. 6) of the master 2 is pressed against the outer peripheral surface of the printing drum 1 by the magnetic attractive force between the printing drum 72 and the printing drum 1.
The front end portion 71 and the magnet portion 72 of the clamper body 71 are substantially flush with the outer peripheral surface of the printing drum 1, and a wide (width W) pressing region is obtained in the circumferential direction of the printing drum 1.

1 is a schematic front view of a stencil printing apparatus according to a first embodiment of the present invention. It is a schematic diagram which shows the damming function which suppresses the tail leak of ink. It is a perspective view which shows a part of opening / closing apparatus of the clamper for rear end sides. It is a figure which shows the opening-and-closing operation | movement of the front end side clamper and the rear end side clamper in a plate discharging process and a plate feeding process. It is a principal part front view which shows the opening / closing operation | movement of the clamp for rear end sides in 2nd Embodiment. It is a principal part front view which shows the opening / closing operation | movement of the clamp for rear end sides in 3rd Embodiment. It is a schematic diagram which shows the bottom leak phenomenon of the ink in the conventional structure.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Printing drum 2 Master-made master 2A Master rear end part 3 Printing paper as a sheet-like recording medium 12 Clamper 13 Press roller as pressing means 20 Impression cylinder 50, 64, 70 Rear end side clamper 57, 66, 71 Clamper body 58, 67 Support member

Claims (6)

On the outer peripheral surface of the printing drum having a perforated region that allows ink to pass through and a non-perforated region that does not allow ink to pass through, the tip of the master that has been made by a clamper provided on the outer peripheral surface is sandwiched between In a stencil printing apparatus that performs printing by winding and transferring the ink supplied from the inside of the printing drum by pressing the sheet-like recording medium against the printing drum by pressing means,
It has a rear end side clamper which is provided on the outer peripheral surface of the printing drum and presses the rear end portion in the winding direction of the master against the outer peripheral surface of the printing drum on the opening area. Stencil printing device. In the stencil printing apparatus according to claim 1,
The rear end side clamper has a flat clamper main body and a support member that rotatably supports the clamper main body, and the front end side of the clamper main body has a shape protruding toward the outer peripheral surface side of the printing drum. A stencil printing apparatus comprising: In the stencil printing apparatus according to claim 1 or 2,
A stencil printing apparatus, wherein the rear end side clamper is pressed by a biasing force of a spring member. In the stencil printing apparatus according to claim 1 or 2,
A stencil printing apparatus, wherein the rear end side clamper is pressed by a magnetic attractive force. In the stencil printing apparatus according to any one of claims 1 to 4,
The stencil printing apparatus, wherein the rear end side clamper is rotatable about 180 ° on the outer peripheral surface of the printing drum. In the stencil printing apparatus according to claim 5,
A stencil printing apparatus, wherein when the rear end side clamper is tilted in a direction not pressing the master, the rear end side clamper is held at a position tilted by a biasing force or a magnetic attractive force of a spring member.

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