JP2007203631A - Mesh screen, plate cylinder of stencil process printing device, and stencil process printing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mesh screen which can effectively prevent the misalignment and creases of a master from occurring, a plate cylinder of a stencil process printing device, and a stencil process printing device. <P>SOLUTION: A projecting part 14a which fits the master 22 is provided to the both side edge parts, of a mesh screen 14 covering an opening part 5c of the plate cylinder 5 around which the master 22 is wrapped. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a stencil printing apparatus, and more particularly to a structure of a plate cylinder in which a master is wound on an outer peripheral surface.

  Conventionally, digital thermal stencil printing is known as a simple printing method. This is because a thermal head having a plurality of fine heating elements is brought into contact with a master obtained by bonding a thermoplastic resin film and a porous support, and the master is placed on a platen roller or the like while energizing the heating elements in a pulsed manner. After the punched image based on the image information is hot-melt perforated and engraved on the thermoplastic resin film of the master by conveying with a conveying means, the perforated master is wound around a porous cylindrical plate cylinder and pressed. By pressing the paper against the outer peripheral surface of the plate cylinder by pressing means such as a roller, the ink supplied to the inner peripheral surface of the plate cylinder is oozed out from the plate cylinder opening portion and the master punching portion, and this ink is transferred to the paper A printed image is obtained on a sheet.

  In the stencil printing apparatus for performing stencil printing, the ink oozed out from the plate cylinder opening when the printing cylinder outer peripheral surface is pressed by the pressing means during printing is a net-like body provided on the surface of the plate cylinder opening. After being diffused by the mesh screen, it passes through the master perforated portion via the master porous support and is transferred onto the paper. At this time, when the thickness of the porous support constituting the master is thick, there is a problem that the amount of ink that enters the voids of the porous support and is discarded increases, and the porous support. If the fibers that make up the complex are intertwined in a complicated manner or if the thick fibers cross the perforated part of the thermoplastic resin film, the solid part of the image may fall out, or fine lines or characters may be cut or blurred. There is a problem that a defect phenomenon called a fiber mesh occurs.

  In order to prevent the occurrence of the above-described problems, attempts have been made to reduce the fiber mesh by thinning the porous support or making the fibers themselves constituting the porous support thin. However, when the thickness of the porous support constituting the master is reduced or the density is reduced, the strength of the master itself is reduced, such as the load during printing, the strength of the main body of the device or the accuracy of the parts themselves, variation during assembly, etc. When the axial deviation occurs between the plate cylinder and the pressing means, the master wound on the plate cylinder at the time of printing for a long time gradually moves in the direction toward the edge of the plate cylinder. The slanting causes problems such as defective printed images or slack or wrinkles in the master area. Conventionally, the position of the plate cylinder and the pressing means was finely adjusted to align the axes, but there was a problem that it was very troublesome. Therefore, for example, “Patent Document 1” discloses a technique for preventing a master from being displaced by providing a member having a high friction coefficient on the outer side in the plate cylinder axis direction of the mesh screen.

JP 2001-301299 A

  According to the technique described above, since the master is prohibited from moving by a member having a high friction coefficient when the pressing means is in pressure contact with the outer peripheral surface of the plate cylinder, the occurrence of a malfunction phenomenon that the master is displaced is prevented. However, when the pressing means is separated from the outer peripheral surface of the plate cylinder, the master wound around the outer peripheral surface of the plate cylinder is in a free state, so that wrinkles may occur when pressed by the pressing means next time. If printing is performed in this state, printing failure occurs.

  SUMMARY OF THE INVENTION It is an object of the present invention to provide a mesh screen, a plate cylinder of a stencil printing apparatus, and a stencil printing apparatus that can solve the above-described problems and can effectively prevent the deviation of the master and the generation of wrinkles on the master. .

The invention described in claim 1 is characterized in that the mesh screen covering the opening portion of the plate cylinder on which the master is wound has projections for locking the master on both side edges thereof.
According to a second aspect of the present invention, in the mesh screen according to the first aspect, the protruding portion is provided over substantially the entire area of the side edge portions.
According to a third aspect of the present invention, in the mesh screen according to the first or second aspect, the protruding amount of the protruding portion is not more than the thickness of the master.
According to a fourth aspect of the present invention, in the mesh screen according to any one of the first to third aspects, the protruding portion is further integrally formed.
A fifth aspect of the present invention is a plate cylinder of a stencil printing apparatus having the mesh screen according to any one of the first to fourth aspects.
The invention described in claim 6 is a stencil printing apparatus having the plate cylinder described in claim 5.
The invention according to claim 7 is the stencil printing apparatus according to claim 6, further comprising pressing means for pressing paper against the master wound on the mesh screen, wherein the width of the mesh screen is the pressing It is characterized by being smaller than the width of the means.

  According to the present invention, the master sticks into the protruding portion due to the pressing force of the pressing means, thereby preventing the master from being displaced on the plate cylinder and preventing the generation of wrinkles with respect to the master, thereby obtaining a good image continuously. be able to. Further, since the projecting portion pierces the master, the master can be held even when the pressing means is separated from the outer peripheral surface of the plate cylinder, and the master is prevented from becoming free. Is reliably prevented.

  FIG. 1 shows a schematic front view of a main part of a stencil printing apparatus adopting the first embodiment of the present invention. In FIG. 1, a stencil printing apparatus 1 includes a printing unit 2, a plate making unit 3, a paper feeding unit 4, and the like.

  The printing unit 2 is located at a substantially central portion of the apparatus main body (not shown) and is driven to rotate in a clockwise direction in FIG. A press roller 6 serving as a pressing unit that presses a sheet fed from the sheet feeding unit 4 to the plate cylinder 5 is provided.

  The plate cylinder 5 includes a porous support plate 5a attached to each peripheral surface of a pair of end plates (not shown) on both side edges thereof, and a mesh screen described later that is wound around the outer periphery of the porous support plate 5a. 14 and an opening 5c having a plurality of openings 5b is formed in the porous support plate 5a. A non-opening portion of the porous support plate 5a is provided with a stage portion 7 having a plane along one generatrix of the plate cylinder 5, and a clamper 8 supported on the stage portion 7 by a support shaft so as to be opened and closed. Is arranged. The clamper 8 is opened and closed by opening / closing means (not shown) when the plate cylinder 5 occupies a predetermined position.

  An ink supply means 9 is disposed inside the plate cylinder 5. The ink supply means 9 includes an ink supply pipe 10 that also serves as a support shaft of the plate cylinder 5, an ink roller 11, a doctor roller 12, and the like. The ink supply pipe 10 is disposed between a pair of end plates (not shown), and each end plate is rotatably supported via a bearing (not shown). An ink pump and an ink pack (not shown) are connected to the ink supply pipe 10, respectively, and the ink in the ink pack is supplied to the inside of the plate cylinder 5 from a plurality of ink supply holes 10 a provided in the ink supply pipe 10 by the operation of the ink pump. To be supplied. The plate cylinder 5 is configured to be detachable from an apparatus main body (not shown) integrally with the ink pump and the ink pack.

  The ink roller 11 is disposed between a pair of end plates (not shown) and is rotatably supported between a pair of side plates (not shown) fixed to the ink supply pipe 10. And is driven to rotate in the same direction. The ink roller 11 is disposed at a position where a slight gap is generated between the peripheral surface thereof and the inner peripheral surface of the plate cylinder 5. A doctor roller 12 is disposed in the vicinity of the ink roller 11. The doctor roller 12 is also rotatably supported between the same side plates (not shown) as the ink roller 11, and is rotated in the reverse direction in synchronization with the ink roller 11 by a rotation driving means (not shown). The doctor roller 12 is disposed at a position where a slight gap is generated between the peripheral surface of the doctor roller 12 and the peripheral surface of the ink roller 11. A space having a wedge-shaped cross section is formed in the vicinity of the ink roller 11 and the doctor roller 12, and the ink reservoir 13 is formed by collecting the ink supplied from the ink supply hole 10a in this space. The ink in the ink reservoir 13 is supplied in a thin layer on the peripheral surface of the ink roller 11 when passing through the vicinity of the ink roller 11 and the doctor roller 12, and the plate cylinder 5 is pressed by the press roller 6 described later. At this time, the peripheral surface of the ink roller 11 and the inner peripheral surface of the plate cylinder 5 come into contact with each other, so that the ink is supplied to the inner peripheral surface of the plate cylinder 5.

  A press roller 6 is disposed below the plate cylinder 5. The press roller 6 formed shorter than the length of the plate cylinder 5 in the axial direction and wound with an elastic body such as rubber around the core 6 a has both ends of the core 6 a between one end of a pair of press roller arms 15. Each is supported rotatably. Each press roller arm 15 that is a plate-like member is rotatably supported at its other end by a support shaft 16 and is swung by a swinging means (not shown). As the press roller arm 15 swings, the press roller 6 separates its peripheral surface from the outer peripheral surface of the plate cylinder 5 as shown in FIG. 1 and the outer peripheral surface of the plate cylinder 5 with a predetermined pressing force. It selectively occupies the pressed position to be brought into contact with.

A plate making unit 3 is disposed on the upper left side of the printing unit 2. The plate making unit 3 includes a master storage unit 17, a thermal head 18, a platen roller 19, a master cutting unit 20, a master transport roller pair 21, and the like. The master storing means 17 supports a master roll 22a formed by winding the master 22 in a roll shape so as to be rotatable and detachable.
The thermal head 18 having a plurality of heating elements is supported by a side plate (not shown) of the plate making unit 3, and the heating element surface is pressed against the peripheral surface of the platen roller 19 by an urging means (not shown). The platen roller 19 is rotatably supported between side plates (not shown) of the plate making unit 3 and is rotationally driven by a stepping motor (not shown).

  The master cutting means 20 has a fixed blade fixed to the plate making section 3 and a movable blade that is movable with respect to the fixed blade. The master 22 rotates or moves up and down with respect to the fixed blade. Disconnect. The master conveying roller pair 21 includes a driving roller that is rotationally driven by a driving unit (not shown), and a driven roller that is disposed in pressure contact with the driving roller and that is driven to rotate when the driving roller rotates, and a thermal head 18 and a platen roller 19. Then, the master 22 transported by plate making is transported toward the printing unit 2.

  A sheet feeding unit 4 is disposed below the plate making unit 3. The paper feed unit 4 is mainly composed of a paper feed tray 23, a paper feed roller 24, a separation roller 25, a separation pad 26, a registration roller pair 27, and the like. A sheet feeding tray 23 on which a large number of sheets P can be stacked on the upper surface is supported by the apparatus main body so as to be movable up and down, and is moved up and down by a lifting means (not shown).

  The paper feed roller 24 is rotatably supported by a bracket (not shown) that is swingably supported by the main body of the apparatus. When the paper feed tray 23 is raised, the paper feed roller 24 is in a predetermined pressure contact with the paper P positioned at the uppermost position. Weld with pressure. The paper feed roller 24 is rotated in the clockwise direction in FIG. 1 by a driving means (not shown), and feeds the uppermost paper on the paper feed tray 23.

  A separation roller 25 is disposed on the downstream side of the paper feeding direction of the paper feeding roller 24. The separation roller 25 is also brought into pressure contact with the uppermost sheet on the paper feed tray 23 with a predetermined pressure contact force, and is driven to rotate in the same direction in synchronization with the paper feed roller 24 by a driving means (not shown). A separation pad 26 is disposed below the separation roller 25. The separation pad 26 is disposed in pressure contact with the circumferential surface of the separation roller 25 with a predetermined pressure contact force. When a plurality of sheets P are pulled out from the sheet feed tray 23 by the sheet feed roller 24 and the separation roller 25, Has a function of separating the two into one sheet. The sheet feeding roller 24, the separation roller 25, and the separation pad 26 constitute a separation feeding unit 28.

  A pair of registration rollers 27 is disposed on the downstream side of the separating and feeding means 28 in the sheet conveying direction. The registration roller pair 27 including the driving roller 27a and the driven roller 27b pressed against the driving roller 27a is driven by transmitting a rotational driving force from a plate cylinder driving unit (not shown) by a driving transmission unit (not shown) such as a gear or a belt. 27a is driven to rotate in synchronization with the rotation of the plate cylinder 5, and feeds the paper P separated and fed by the separation feeding means 28 toward the printing unit 2 at a predetermined timing. The feeding timing of the paper P by the registration roller pair 27 is a predetermined timing at which the image leading edge position in the plate cylinder rotation direction of the master 22 that has been pre-rolled around the printing drum 5 coincides with the leading edge of the image forming area of the paper P. The timing is set. Further, in this embodiment, the driven roller 27 b is disposed so as to be able to be pressed against and separated from the driving roller 27 a by contact / separation means (not shown), and the sheet P fed from the registration roller pair 27 is the outer peripheral surface of the plate cylinder 5. And the press roller 6, the contact / separation means (not shown) is operated to move the driven roller 27 b away from the drive roller 27 a.

  On the upper left side of the printing unit 2 is disposed a plate discharging unit (not shown) that peels off the used master from the outer peripheral surface of the plate cylinder 5 and discards it. A plate discharging unit (not shown) has a plate discharging roller pair, a plate discharging box, a compression plate, and the like. The end of the used master is scooped up and transferred from the outer peripheral surface of the plate cylinder 5 by the plate discharging roller pair. The accommodated master is accommodated in the discharge box, and the accommodated master is compressed with a compression plate.

  A paper discharge unit (not shown) that peels and conveys the printed paper P from the peripheral surface of the plate cylinder 5 is disposed below the plate discharge unit (not shown). A paper discharge unit (not shown) includes a peeling claw, a peeling fan, a paper discharge conveying member, a paper discharge tray, and the like, and printed paper from the outer peripheral surface of the plate cylinder 5 by the cooperative operation of the peeling claw and the peeling fan. 1 is transported to the left in FIG. 1 by a paper delivery transport member comprising a suction transport conveyor, and the printed paper is transported onto a paper delivery tray disposed at the most downstream position in the paper transport direction. The sheets P are sequentially stacked.

  Here, the mesh screen 14 which is a characteristic part of the present invention will be described. The mesh screen 14 formed by weaving a wire made of a material such as metal or resin is wound on a porous support plate 5a corresponding to the opening 5c as shown in FIG. 22 is wound. The mesh screen 14 is formed such that the width, which is the length of the plate cylinder in the axial direction, is smaller than the axial length of the press roller 6, and protruding portions for locking the master 22 at both side edges. As shown in FIG. 3, a plurality of protrusions 14 a are formed toward the winding surface side of the master 22. The mesh screen 14 is formed by shearing by shearing or the like. By managing the clearance between the upper blade and the lower blade in advance during the shearing, a plurality of fine protrusions 14a are formed in a burr shape. The height of each protrusion 14a is equal to or less than the thickness of the master 22 (the sum of the thickness of the porous support and the thickness of the thermoplastic resin film) from the viewpoint of protecting the surface of the press roller 6 and preventing perforation of the master 22. It is formed to become. For example, when the thickness of the master 22 is 50 μm, the height of each protruding portion 14 a is about 5 to 10 μm at a minimum and about 30 to 50 μm at a maximum. Further, in the present embodiment, an example is shown in which the protrusions 14a are continuously formed over almost the entire area of both side edges of the mesh screen 14, but the meshes may be formed even if the protrusions are formed at predetermined intervals. It may be formed only at the upstream end and the downstream end of the screen 14.

Based on the above configuration, the operation of the stencil printing apparatus 1 will be described below.
When a document to be printed is set in an image reading unit (not shown) provided at the upper part of the apparatus main body and a plate making start key on an operation panel (not shown) is pressed, a document image reading operation is performed in the image reading unit (not shown). At the same time, a plate discharging operation is performed in which a used master is peeled off from the outer peripheral surface of the plate cylinder 5 at a plate discharging portion (not shown). When the plate removal operation is completed, the plate cylinder 5 rotates and stops to the home position where the clamper 8 is located almost right side. The opening / closing means (not shown) is activated to open the clamper 8, and the stencil printing apparatus 1 waits for plate supply. It becomes a state.

  When the stencil printing apparatus 1 enters a plate feeding standby state, a plate making operation is subsequently performed. A stepping motor and driving means (not shown) are operated to rotate and drive the platen roller 19 and the master transport roller pair 21, and the master 22 is pulled out from the master roll 22a. The drawn master 22 is heated and perforated by a plurality of heating elements when passing through the thermal head 18 to form a plate-making image. The master 22 having been subjected to the plate-making image is conveyed toward the clamper 8 opened by the platen roller 19 and the master conveyance roller pair 21.

  When the control means (not shown) determines that the leading end of the master 22 has reached the predetermined position between the stage unit 7 and the clamper 8 from the number of steps of the stepping motor (not shown), the opening / closing means (not shown) is activated and the clamper 8 is operated. The front end of the master 22 is locked onto the outer peripheral surface of the plate cylinder 5. Thereafter, the plate cylinder 5 is rotationally driven in the clockwise direction in FIG. 1 at the same peripheral speed as the conveyance speed of the master 22, and the winding operation of the master 22 around the plate cylinder 5 is performed. When it is determined that the plate making for one plate has been completed from the number of steps of the stepping motor (not shown), the rotation of the platen roller 19 and the master transport roller pair 21 is stopped, and the master cutting means 20 is activated to operate the master 22. Disconnected. The cut master 22 is pulled out of the plate making unit 3 by the rotation of the plate cylinder 5, and when the plate cylinder 5 stops again at the home position, the plate making operation and the winding operation are completed.

  The printing operation is performed following the winding operation. The plate cylinder 5 starts to rotate at a low speed, and one sheet is fed from the sheet feeding unit 3 by the operation of the separation feeding unit 28, and the fed sheet P is held by the registration roller pair 27. Then, the registration roller pair 27 is rotated at a timing when the leading end of the plate-making image formed on the master 22 wound around the plate cylinder 5 reaches a position corresponding to the press roller 6, and the sheet P is transferred to the plate cylinder 5 and the press roller. It is fed toward 6 and. Immediately after this, a swinging means (not shown) is operated, and the peripheral surface of the press roller 6 is pressed against the outer peripheral surface of the plate cylinder 5.

  By this pressing operation, the press roller 6, the paper P, the master 22, and the outer peripheral surface of the plate cylinder 5 are pressed against each other, and the ink supplied to the inner peripheral surface of the plate cylinder 5 by the ink roller 11 is the opening portion of the plate cylinder 5. Then, it is transferred to the paper P through a mesh screen (not shown), a porous support of the master 22 and a perforated portion of a thermoplastic resin film, and so-called printing is performed. The paper P to which the ink has been transferred by printing is sent to a paper discharge unit (not shown) and discharged onto a paper discharge tray (not shown). The plate making operation is completed by this series of steps, and the stencil printing apparatus 1 enters a printing standby state.

  Thereafter, when a test printing key on the operation panel (not shown) is pressed by the operator, the plate cylinder 5 is driven to rotate at a higher speed than that at the time of printing and one sheet P is separated and fed from the sheet feeding unit 4. . The paper P separated and fed is pressed against the outer peripheral surface of the plate cylinder 5 by the press roller 6 in the same manner as described above, and then is peeled off from the outer peripheral surface of the plate cylinder 5 and is not shown. Discharged to the top.

  After confirming the density or position of the printed image by trial printing, adjusting these with various keys on the operation panel (not shown), and performing test printing again, setting the number of prints and the printing speed, and then performing an operation not shown by the operator When the print start key on the panel is pressed, the plate cylinder 5 rotates at a rotational peripheral speed corresponding to the set printing speed, and the paper is continuously fed from the paper supply unit 4 to perform a printing operation. . When the set number of prints is consumed, the plate cylinder 5 stops at the home position, and the stencil printing apparatus 1 enters the print standby state again.

  As shown in FIG. 4, when the press roller 6 is pressed against the outer peripheral surface of the plate cylinder 5 at the time of printing, trial printing, and printing described above, the protrusions 14 a are located on the inner side of the both end portions of the press roller 6. Is provided, the master 22 pierces the projecting portions 14a by the pressing force of the press roller 6, thereby preventing the master 22 from being displaced on the plate cylinder 5 and preventing the wrinkle from being generated on the master 22. And good images can be obtained continuously. In the present invention, since each protrusion 14a pierces the master 22, even if the press roller 6 is separated from the outer peripheral surface of the plate cylinder 5 as compared with the configuration using the conventional high friction resistance member, Can be held, the master 22 is prevented from becoming free, and the positional deviation of the master 22 is reliably prevented.

  Further, in the above-described embodiment, each protrusion 14a is integrally formed on the mesh screen 14. Therefore, the cost can be greatly reduced as compared with a configuration in which each protrusion 14a is added by post-processing, and retrofitting. This can prevent the thickness of the mesh screen 14 from changing partially (the original mesh screen portion and each projecting portion retrofitted), causing a problem that wrinkles occur due to a load on the master 22 due to a difference in peripheral speed. Can be prevented.

  If the above-described effects of integration of the protrusions are not desired, as shown in FIG. 5, a mesh having a structure in which protrusions 29b made of protruding metal powder or the like are retrofitted to both side edges by an adhesive 29a as shown in FIG. As shown in FIG. 6, a screen 29 having a configuration in which protrusions 30b having protrusions are retrofitted by tapes 30a on both side edges as shown in FIG. 6 may be used.

It is a principal part schematic front view of the stencil printing apparatus which employ | adopted one Embodiment of this invention. It is the schematic explaining the plate cylinder and press roller used for one Embodiment of this invention. It is the schematic explaining the mesh screen used for one Embodiment of this invention, and the protrusion part formed in this. It is the schematic which shows the press-contact state of the plate cylinder and press roller in one Embodiment of this invention. It is the schematic which shows the mesh screen used for the modification of one Embodiment of this invention. It is the schematic which shows the mesh screen used for the other modification of one Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Stencil printing apparatus 5 Plate cylinder 5c Opening part 6 Pressing means 14, 29, 30 Mesh screen 14a, 29b, 30b Protrusion part 22 Master P paper

Claims (7)

In the mesh screen covering the opening of the plate cylinder on which the master is wound,
A mesh screen having protrusions for locking the master at both side edges. The mesh screen according to claim 1,
The mesh screen according to claim 1, wherein the protrusion is provided over substantially the entire area of the side edges. The mesh screen according to claim 1 or 2,
The mesh screen according to claim 1, wherein a protrusion amount of the protrusion is equal to or less than a thickness of the master. The mesh screen according to any one of claims 1 to 3,
The mesh screen, wherein the protrusion is integrally formed.   A plate cylinder of a stencil printing apparatus comprising the mesh screen according to any one of claims 1 to 4.   A stencil printing apparatus comprising the plate cylinder according to claim 5. In the stencil printing apparatus according to claim 6,
A stencil printing apparatus comprising pressing means for pressing paper against a master wound on the mesh screen, wherein the width of the mesh screen is smaller than the width of the pressing means.

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