JP2007105995A - Plate cylinder of stencil printing equipment and stencil printing equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide the plate cylinder of a stencil printing equipment, in which wrinkles in a master can be effectively prevented from developing, and the stencil printing equipment. <P>SOLUTION: In the plate cylinder 5 of the stencil printing equipment 1, around which the master 22 with an opening part 5c is wound, a projected part 14 is provided near the downstream side end part in the rotational direction of the plate cylinder except its middle part of the opening part 5c. <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 this stencil printing apparatus that performs stencil printing, ink exudes from the plate cylinder opening when the outer periphery of the plate cylinder is pressed by the pressing means during printing, but ink does not exude in the non-perforated part of the master. The accumulated ink is pushed to the rear end of the master by the pressing means and eventually protrudes from the rear end of the master and causes the inside of the machine to be fouled.

  In order to prevent the above-mentioned spilling phenomenon, a stencil printing apparatus having an ink non-passing portion that is polymerized with the rear portion of the aperture region of the porous support plate constituting the plate cylinder and guides the intruded ink to the rear portion of the aperture region, for example, For example, a stencil printing apparatus in which a weir element made of an ink impermeable material is arranged at the front edge of the plate cylinder rotating direction of an ink impermeable zone of a porous support plate is disclosed in, for example, “Patent Document 2”. Are each disclosed.

Japanese Patent No. 2860218 Japanese Patent Publication No. 60-28670

  According to each technique described above, since the accumulated ink is returned to the inside of the plate cylinder, the occurrence of a tail leakage phenomenon is prevented. However, when the outer surface of the plate cylinder is pressed by the pressing means during printing, the master is gradually extended due to the impact load when the pressing means is pressed against the plate cylinder or the conveyance resistance that the paper receives from the separation paper feeder. There is a problem that wrinkles occur on the downstream side of the plate cylinder rotation direction. This wrinkle is caused by a difference in elongation between the part where the ink is attached and the part where the ink is not attached due to the influence of moisture etc. contained in the ink. On the other hand, since the central portion extends, it occurs in the central portion in the width direction of the master, and it is noticeable in the master having a low strength of the porous support constituting the master for the purpose of reducing the occurrence of fiber mesh. The generated wrinkles initially grow from the non-plate making area, which is the rear end thereof, to reach the plate making area as the printing process continues, and if printing is performed in this state, printing defects occur.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a plate cylinder and a stencil printing apparatus for a stencil printing apparatus that can solve the above-mentioned problems and can effectively prevent the generation of wrinkles on the master.

  According to the first aspect of the present invention, in the plate cylinder of the stencil printing apparatus having an aperture and winding a master, a protrusion is provided in the vicinity of the downstream end of the aperture in the plate cylinder rotation direction excluding the central portion. It is characterized by having.

  According to a second aspect of the present invention, in the plate cylinder of the stencil printing apparatus according to the first aspect, when the paper is further pressed by the pressing means attached to the stencil printing apparatus, the protrusion is on the downstream side in the plate cylinder rotation direction. It consists of the elastic body which can deform | transform toward.

  According to a third aspect of the present invention, in the plate cylinder of the stencil printing apparatus according to the second aspect, the protruding portion has a lower hardness than the pressing means.

  According to a fourth aspect of the present invention, in the plate cylinder of the stencil printing apparatus according to any one of the first to third aspects, the protruding portion is made of a high friction resistance member.

  A fifth aspect of the present invention is a stencil printing apparatus having the plate cylinder according to any one of the first to fourth aspects.

  According to the present invention, the apparent diameter of the plate cylinder increases only at the projecting portion disposition position, and accordingly, the rotational peripheral speed of the plate cylinder increases only at the projecting portion disposition position, thereby pressing the projecting portion against the projecting portion. By acting to increase the rotational peripheral speed of the means, the master wound on the outer peripheral surface of the plate cylinder extends more downstream than the other portions at the position where the protrusion is disposed than the other portions. In addition, the difference in elongation of the master from the plate cylinder opening area is absorbed, so that generation of wrinkles on the master is prevented, and good printing operation can be continuously performed.

  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, and a mesh screen (not shown) wound around the outer periphery of the porous support plate 5a. In the porous support plate 5a, an opening 5c having a plurality of openings 5b is formed. 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.

  In the vicinity of the opening 5c of the porous support plate 5a and on the master rear end side, which is downstream of the plate cylinder rotation direction as viewed from the stage section 7, the center in the axial direction of the plate cylinder 5 as shown in FIG. A protruding portion 14 made of a rectangular parallelepiped having a rectangular cross section is disposed at a portion to be removed. The protruding portion 14 is formed of a foamed material such as sponge, an elastic body made of a low elastic solid rubber, a low elastic resin or the like, and as shown in FIG. Are fixed on the non-opening portions located further downstream of the plate cylinder in the rotational direction of the plate cylinder, substantially corresponding to both side edges of the opening portion 5c and in contact with the press roller 6 described later. Yes. The height of the projecting portion 14 is set to a height (5 mm in the present embodiment) that does not contact the peripheral surface of the press roller 6 when the press roller 6 is separated from the outer peripheral surface of the plate cylinder 5 in consideration of dirt, wear, and the like. In addition, the hardness of the protrusion 14 is set to be lower than the hardness of the peripheral surface of the press roller 6.

  A press roller 6 is disposed below the plate cylinder 5. A press roller 6 having a length substantially the same as the axial length of the plate cylinder 5 and having an elastic body such as rubber wound around the core portion 6 a is formed at both ends of the core portion 6 a with a pair of press roller arms 15. Each end is rotatably supported. 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.

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.

  At the time of printing, test printing, and printing described above, after the ink transfer to the paper P is completed and the rear end of the paper P is separated from the press contact portion between the plate cylinder 5 and the press roller 6, the press roller 6 The circumferential surface is brought into pressure contact with each protrusion 14. At the time of this pressure contact, the projections 14 are arranged, so that the apparent diameter of the plate cylinder 5 increases only at the positions where the projections 14 are arranged, and accordingly, the rotational peripheral speed of the plate cylinder 5 increases. By increasing only at the position where the portion 14 is disposed, the rotational peripheral speed of the press roller 6 in pressure contact with each protrusion 14 is increased. As a result, the master 22 wound on the outer peripheral surface of the plate cylinder 5 is extended to the downstream side in the plate cylinder rotation direction more than other portions at the positions where the protrusions 14 are disposed, and the plate cylinder opening region The difference in the elongation of the master 22 between the two is absorbed, so that the generation of wrinkles on the master 22 is prevented, and a good printing operation can be continued.

  Further, each protrusion 14 is made of an elastic body having a hardness lower than the peripheral surface hardness of the press roller 6, and when the press roller 6 presses, each protrusion 14 moves downstream in the plate cylinder rotation direction as shown in FIG. 3. Therefore, the master 22 is further extended toward the downstream side in the plate cylinder rotation direction, and the generation of wrinkles on the master 22 is further prevented. Further, by using a high frictional resistance member as each protrusion 14, the master 22 is further extended downstream in the plate cylinder rotation direction, and the generation of wrinkles on the master 22 is further prevented.

  In the above embodiment, an example is used in which the plate cylinder 5 is formed of a rectangular parallelepiped having a rectangular cross section, and has a protruding portion 14 formed of an elastic body made of a foamed body such as sponge, a low elastic solid rubber, a low elastic resin, or the like. Although shown, the plate cylinder having the protruding portion is not limited to this. For example, as shown in FIG. 4, a plate cylinder 5A having a protruding portion 29 formed longer in the plate cylinder axis direction than the protruding portion 14 as shown in FIG. As shown in FIG. 6, a plate cylinder 5B having protrusions 30 in a form in which two rows of protrusions 14 are arranged in the circumferential direction of the plate cylinder, a plate cylinder 5C having protrusions 31 having a trapezoidal cross section as shown in FIG. A plate cylinder having protrusions of various shapes and materials may be used. As these protrusions, those having the optimum shape and material are selected each time depending on the type (smoothness, strength, etc.) of the master 22 to be used. In any case, the center in the plate cylinder axis direction is selected. Except for the plate cylinder rotation direction except the downstream side.

It is a principal part schematic front view of the stencil printing apparatus which employ | adopted one Embodiment of this invention. It is a schematic perspective view explaining the plate cylinder used for one Embodiment of this invention. It is a principal part schematic front view of the stencil printing apparatus for demonstrating printing operation in one Embodiment of this invention. It is a schematic perspective view which shows the plate cylinder used for the modification of one Embodiment of this invention. It is a schematic perspective view which shows the plate cylinder used for the other modification of one Embodiment of this invention. It is a schematic perspective view which shows the plate cylinder used for the further another modification of one Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Stencil printing apparatus 5,5A, 5B, 5C Plate cylinder 5c Opening part 6 Pressing means (press roller)
14, 29, 30, 31 Projection 22 Master P Paper

Claims (5)

In a plate cylinder of a stencil printing apparatus having an opening and winding a master,
A plate cylinder of a stencil printing apparatus, characterized in that it has a protruding portion in the vicinity of the downstream end portion in the plate cylinder rotation direction excluding the central portion of the opening portion. In the plate cylinder of the stencil printing apparatus according to claim 1,
A plate cylinder of a stencil printing apparatus, comprising: an elastic body that is deformable toward a downstream side in a plate cylinder rotation direction when the paper is pressed by a pressing unit attached to the stencil printing apparatus. In the plate cylinder of the stencil printing apparatus according to claim 2,
A plate cylinder of a stencil printing apparatus, wherein the protrusion has a lower hardness than the pressing means. In the plate cylinder of the stencil printing apparatus according to any one of claims 1 to 3,
A plate cylinder of a stencil printing apparatus, wherein the protrusion is made of a high friction resistance member. A stencil printing apparatus comprising the plate cylinder according to any one of claims 1 to 4.

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