JP4833601B2 - Stencil printing machine - Google Patents

Description

  The present invention relates to a stencil printing apparatus that obtains a printed image by pressing a sheet against a master wound around a plate cylinder, and more particularly to control of a blowing unit that blows air between the master and a sheet in order to separate the sheet. .

  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 that performs the stencil printing described above, generally printed paper is peeled from a master that has been pre-rolled on the outer peripheral surface of the plate cylinder by a peeling claw that is a paper peeling member. This peeling claw is disposed in the vicinity of the outer peripheral surface of the plate cylinder with a slight gap between its tip and the outer peripheral surface of the plate cylinder so as not to damage the master, and is forced between the paper and the master. The paper is peeled off from the outer peripheral surface of the plate cylinder. However, when the ambient temperature / humidity is high or the printing speed is slow, the amount of ink oozing out from the inside of the plate cylinder is large, and the adhesive strength of the paper to the master by the ink is high (particularly, the plate-making image has a solid part). This is a problem of so-called “rolling up”, in which the paper cannot be peeled off by the peeling claw and the paper remains stuck on the master or the paper is caught by the peeling claw and the peeling operation is not performed reliably. Will occur.

  Therefore, a stencil printing apparatus provided with a peeling device that expels air from the tip of the peeling claw toward the master on the outer periphery of the plate cylinder and urges the peeling of the paper is disclosed in, for example, “Patent Document 1”. Has been. Also, a peeling device that ejects air at different periods toward the master and the paper on the outer peripheral surface of the plate cylinder and toward the paper so that the paper released from the outer peripheral surface of the plate cylinder is separated from the peeling claw. A stencil printing apparatus including the above is disclosed in, for example, “Patent Document 2”. Furthermore, a stencil printing apparatus provided with a peeling device provided with a wind direction changing means for changing the direction of air blowing in order to reliably peel off the paper from the master on the outer peripheral surface of the plate cylinder corresponding to various printing conditions is, for example, “patent Document 3 ”.

No. 4-15509 Japanese Patent Laid-Open No. 5-50737 JP 2000-301818 A

  In each of the above-described technologies, when the air is blown from the peeling device before the press timing of the paper to the outer peripheral surface of the plate cylinder by the press roller, that is, at the timing when it is not necessary to release the paper from the master on the outer peripheral surface of the plate cylinder. When the paper reaches the contact position between the plate cylinder and the press roller, the leading end of the paper causes a violent vertical movement. As a result, the timing at which the leading edge of the paper collides with the press roller and enters the contact position is delayed, and the image position is shifted. When the image is transferred by the subsequent pressing operation after transfer, the printed image is blurred, or the leading edge of the paper collides with the press roller, causing the paper to be bent, slack, or wrinkled. There is a problem.

  SUMMARY OF THE INVENTION The present invention provides a stencil printing apparatus having a peeling device that solves the above-mentioned problems and can satisfactorily peel the paper from the outer peripheral surface of the plate cylinder while preventing the occurrence of problems on the printed image and the paper. Objective.

According to the first aspect of the present invention, there is provided a plate cylinder on which a master having a plate-making image formed on an outer peripheral surface is wound, a pressing unit that is detachable from the outer peripheral surface and presses a sheet against the master, and and moving means for contacting and separating the pressing means relative to said outer peripheral surface, and a blowing means for the sheet subjected to air blowing to the contact portion between the sheet and the master is separated from the master possess, the by the pressing means In the stencil printing apparatus in which the air is blown by the blowing unit after the paper is pressed against the outer peripheral surface, the blowing unit includes a housing having a blowing fan for blowing air, and the blower fan formed in the housing. An opening and closing member that selectively occupies an opening position that is supported by the housing and opens the blowing opening and a closed position that closes the blowing opening, and the opening and closing opening. Opening and closing to open and close members And the opening / closing member is opened / closed in synchronism with the operation of the contact / separation means, and the opening / closing member occupies the open position of the blowing means, and the blowing opening is opened. The air blowing to the contact portion is performed when the air-operating device is closed, and the air blowing to the contact portion is stopped when the opening / closing member occupies the closed position and the air blowing port is closed .

According to a second aspect of the present invention, in the stencil printing apparatus according to the first aspect of the present invention, the opening / closing means further determines a ratio of the opening / closing member occupying an open position during one contact / separation operation of the pressing member by the contact / separation means. It is configured to be changeable .

According to a third aspect of the present invention, in the stencil printing apparatus according to the first or second aspect , the stencil printing apparatus further includes an openable / closable discharge port for discharging the air flow from the inside of the casing .

According to a fourth aspect of the present invention, in the stencil printing apparatus according to the third aspect of the present invention, the stencil printing apparatus further includes a sheet conveying unit that conveys the sheet separated from the master, and the discharge port has the air flow separated from the master. It is arranged at a position for discharging toward the paper conveying means via the paper .

According to a fifth aspect of the present invention, in the stencil printing apparatus according to the third or fourth aspect , the discharge port is further opened and closed by the open / close member , and the discharge port is opened when the open / close member occupies an open position. The outlet is opened when closed and the opening / closing member occupies a closed position .

The invention according to claim 6 is the stencil printing apparatus according to claim 3 or 4 , further comprising a first discharge port opening / closing means for opening and closing the discharge port, wherein the first discharge port opening / closing means is the plate making image. The discharge port is closed corresponding to a portion having a high image density .

According to a seventh aspect of the present invention, in the stencil printing apparatus according to the fourth aspect , a plurality of the discharge ports are provided in the width direction of the sheet, and the second discharge port opening / closing means for individually opening and closing the discharge ports. And the second outlet opening / closing means opens and closes each outlet corresponding to the width of the sheet .

According to an eighth aspect of the present invention, in the stencil printing apparatus according to the fourth aspect , a plurality of the discharge ports are provided in the width direction of the sheet, and third discharge port opening / closing means for individually opening and closing the discharge ports. And a third discharge port opening / closing means closes each discharge port corresponding to a portion where the image density of the plate-making image is high, and opens / closes each discharge port corresponding to the size of the paper. It is characterized by.

According to a ninth aspect of the present invention, in the stencil printing apparatus according to the fourth aspect of the present invention, a plurality of the discharge ports are further provided in the transport direction of the paper, and a fourth discharge port opening / closing is performed to open and close each discharge port individually. And a paper length detecting means for detecting in advance the length of the paper in the conveyance direction, and the fourth discharge port opening / closing means is provided at the leading edge of the paper conveyed based on the detection result of the paper length detection means. The discharge ports are sequentially opened from the discharge port at the most upstream position in the sheet conveyance direction, and finally only the discharge port at the most downstream position in the sheet conveyance direction is opened toward the rear end of the sheet. And

According to a tenth aspect of the present invention, in the stencil printing apparatus according to the ninth aspect , a plurality of the discharge ports are provided in the conveyance direction of the paper and a plurality of rows in the width direction of the paper, and the discharge ports are opened and closed. A fifth discharge port opening / closing unit that is individually performed, and a sheet length detection unit that detects a length in the conveyance direction of the sheet in advance, and the fifth discharge port opening / closing unit includes the image density of the plate-making image and the width of the sheet. And each said discharge port is opened and closed corresponding to length .

  According to the present invention, after the pressing means presses the sheet to the plate cylinder and the leading end of the sheet is held at the contact portion between the plate cylinder and the pressing means, the opening / closing member occupies the open position, thereby blowing the air. Since the air flow from the plate is sent between the pre-printed master wound on the outer peripheral surface of the plate cylinder and the leading edge of the paper, the air flow from the air blowing means prevents the leading edge of the paper from moving up and down violently. Thus, it is possible to satisfactorily peel the paper from the outer peripheral surface of the plate cylinder while preventing the occurrence of image position shift, blurring image, paper folding, paper wrinkling, and the like due to this.

  FIG. 1 is a schematic front view 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, a plate discharging unit 5, a paper discharging unit 6, an image reading unit 7, and the like.

  The printing unit 2 is located at substantially the center of the apparatus main body 8 and is rotated and driven in the direction indicated by the arrow A in FIG. A press roller 10 is provided as a pressing unit that presses a sheet P that is freely provided and is fed from the sheet feeding unit 4 against the plate cylinder 9.

  The plate cylinder 9 has a porous support plate having both side edges attached to each peripheral surface of a pair of end plates (not shown), and a mesh screen wound around the outer peripheral surface of the porous support plate. The porous support plate is provided with an opening portion having a plurality of openings and a non-opening portion. An openable / closable clamper 11 is disposed in the non-opening portion, and the clamper 11 is opened and closed by an opening / closing means (not shown) when the plate cylinder 9 occupies a predetermined position.

  An ink supply means 12 is disposed inside the plate cylinder 9. The ink supply means 12 is mainly composed of an ink supply pipe 13 that also serves as a support shaft of the plate cylinder 9, an ink roller 14, a doctor roller 15, and the like.

  The ink supply pipe 13 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 respectively connected to the ink supply pipe 13, and the ink in the ink pack is moved into the plate cylinder 9 from the ink supply holes provided in the ink supply pipe 13 by the operation of the ink pump. Supplied.

  The ink roller 14 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 13. 1 is rotated in the clockwise direction in FIG. The ink roller 14 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 9.

  A doctor roller 15 is disposed in the vicinity of the ink roller 14. The doctor roller 15 is also rotatably supported between the same side plates (not shown) as the ink roller 14, and is rotated in the reverse direction in synchronization with the ink roller 14 by a rotation driving means (not shown). The doctor roller 15 is disposed at a position where a slight gap is generated between the peripheral surface of the doctor roller 15 and the peripheral surface of the ink roller 14.

  A space having a wedge-shaped cross section is formed in the vicinity of the ink roller 14 and the doctor roller 15, and the ink reservoir 16 is formed by storing the ink supplied from the ink supply pipe 13 in this space. The ink in the ink reservoir 16 is supplied as a thin film to the peripheral surface of the ink roller 14 when passing through the proximity of the ink roller 14 and the doctor roller 15, and when the plate cylinder 9 is pressed by the press roller 10 described later. Further, when the peripheral surface of the ink roller 14 and the inner peripheral surface of the plate cylinder 9 are in contact with each other, the ink is supplied to the inner peripheral surface of the plate cylinder 9.

  A press roller 10 is disposed below the plate cylinder 9. As shown in FIG. 2, the press roller 10 is rotatably supported at both ends of a support shaft 10a by a pair of arm members 17, and the arm member 17 swings relative to the outer peripheral surface of the plate cylinder 9. It is configured so that it can be touched and separated.

  Each arm member 17 having an approximately L-shape and having arm portions 17 a and 17 b is fixed to a support shaft 18 that is rotatably supported by the apparatus main body 8, and is integrated with the apparatus main body 8. It is supported rotatably. Each arm member 17 rotatably supports the press roller 10 at a substantially central position of the arm portion 17a, and a cam follower 19 is rotatably attached to the tip of the arm portion 17a of one arm member 17. . Further, a notch 17c and an engaging corner 17d are formed at the tip of the arm portion 17b of each arm member 17, and one end is locked to a pin 20 fixed to the apparatus body 8 near the tip. The other ends of the printed pressure springs 21 are locked by holes 22 respectively.

  In the vicinity of the cam follower 19, a support shaft 23 c that is rotatably supported by the apparatus main body 8 is fixed, and a rotational force from a plate cylinder driving means (not shown) is transmitted to synchronize with the rotation of the plate cylinder 9 as shown in FIG. A printing cam 23 having a large-diameter portion 23a and a small-diameter portion 23b that rotates in the direction indicated by the arrow B is disposed. With the configuration described above, when the large-diameter portion 23a abuts on the cam follower 19, each arm member 17 rotates counterclockwise in FIG. 2 about the support shaft 18 against the urging force of the printing pressure spring 21. The press roller 10 occupies a separation position in which the circumferential surface is separated from the circumferential surface of the plate cylinder 9. When the printing pressure cam 23 is rotated from this state and the contact state between the large diameter portion 23 a and the cam follower 19 is released, each arm member 17 is centered on the support shaft 18 by the biasing force of the printing pressure spring 21. , The press roller 10 occupies a press contact position where the peripheral surface is pressed against the peripheral surface of the plate cylinder 9 with a predetermined printing pressure corresponding to the urging force of the printing pressure spring 21. At this time, a gap is formed between the small diameter portion 23 b and the cam follower 19.

  In the above-described configuration, each arm member 17, support shaft 18, cam follower 19, pin 20, printing pressure spring 21, hole 22, and printing pressure cam 23 make the peripheral surface of the press roller 10 with respect to the outer peripheral surface of the plate cylinder 9. Contact / separation means 24 for contacting / separating is configured.

  An arm stopper 25 is disposed below each arm member 17. Each arm stopper 25 includes a stay 25a that is swingably provided on a support shaft 26 fixed to the apparatus main body 8 at an approximately middle position, and an engagement portion 25b that is screwed to one end of the stay 25a. And is rotatably supported integrally with the apparatus main body 8.

  Standing bent portions 25c and 25d are formed at one end of each stay 25a, and taps (not shown) are formed between the standing bent portions 25c and 25d, respectively. Each engaging portion 25b having a long hole is attached in a slidable state between the standing bent portions 25c and 25d, and is fixed to a predetermined position by a screw 30. This position will be described later. Each engagement portion 25b is formed with an engagement protrusion 25e that engages with each engagement corner portion 17d.

  At the other end of each stay 25a, the other end of a tension spring 28, one end of which is locked to a pin 27 fixed to the apparatus main body 8, is locked by a hole 29. A plunger 31 a of a pull-type solenoid 31 attached to the apparatus main body 8 is rotatably attached to the left position by a pin 32. A stopper 33 is disposed on the apparatus main body 8 located below the other end of each stay 25a. Each arm stopper 25 occupies the position shown in FIG. 2 when each solenoid 31 is on. 2 is rotated about the support shaft 26 in the clockwise direction in FIG. 2 by the urging force of each tension spring 28, and the stay 25 a occupies a position where it abuts against the stopper 33.

  With the above-described configuration, each arm stopper 25 occupies an engagement position where the engagement projection 25e can engage the engagement corner portion 17d when the solenoid 31 is off, and is engaged when the solenoid 31 is on. It occupies a release position where the engagement state of the engagement corner 17d by the mating protrusion 25e is released.

  Here, the attachment position of each engaging part 25b with respect to each stay 25a will be described. As described above, when the solenoid 31 is turned off when the large-diameter portion 23a contacts the cam follower 19 and the press roller 10 occupies the separated position, each arm stopper 25 is displaced by the urging force of the tension spring 28. Occupies the engagement position. At this time, in order to smoothly hold and release each arm member 17 by each arm stopper 25, as shown in FIG. 3, a predetermined gap G is formed between the engagement corner portion 17d and the engagement protrusion 25e. Is provided. The gap G corresponds to the optimum gap G between the tip corner 17d and the engagement protrusion 25e by loosening the screw 30 with the large-diameter portion 23a abutting against the cam follower 19 during device assembly or maintenance. It is set by tightening the screw 30 again with a jig such as a shim interposed.

  By adjusting the gap G described above, for example, if the gap G is set larger, the holding operation of each arm member 17 can be performed with a margin even if the cam follower 19 does not reach the large diameter portion 23a. However, if the gap G is too large, when the plate cylinder 9 is rotated without pressing the press roller 10 against the plate cylinder 9, such as during an ink supply operation for supplying ink to the inner peripheral surface of the plate cylinder 9, That is, when the plate cylinder 9 is rotated with each arm member 17 held by each arm stopper 25, the printing follower cam 19 is rotated from the large diameter portion 23a because the printing cam 23 rotates in synchronization with the rotation of the plate cylinder 9. The contact sound and vibration between the cam follower 19 and the large-diameter portion 23a generated by the swing of each arm member 17 by the biasing force of the printing pressure spring 21 when it is detached, the engagement corner portion 17d and the engagement protrusion 25e The contact sound and vibration will increase. Accordingly, the size of the gap G is set to about 0.3 to 0.5 mm including variations during adjustment work in a normal stencil printing apparatus as shown in the present embodiment.

  A plate making unit 3 is disposed on the upper right side of the printing unit 2. The plate making unit 3 includes a master storage unit 34, a platen roller 35, a thermal head 36, a master cutting unit 37, a master transport roller pair 38, 39, and the like.

  The master storage means 34 is disposed between the side plates (not shown) of the plate-making part 3, and is a master roll 40a formed by winding a master 40 formed by laminating a thermoplastic resin film and a porous support in a roll shape. The core part is supported rotatably and detachably.

  The platen roller 35 is rotatably supported between side plates (not shown) of the plate making unit 3 and is driven to rotate by a stepping motor 41 provided in the apparatus main body 8. The thermal head 36 has a plurality of heat generating elements. The surface of the heat generating element is brought into contact with the peripheral surface of the platen roller 35, and the thermoplastic resin film surface of the master 40 is heated, melted and punched. The thermal head 36 is pressed against the peripheral surface of the platen roller 35 with a predetermined pressing force by an urging means (not shown).

  The master cutting means 37 has a fixed blade and a movable blade, and has a known configuration in which the master 40 is cut by moving the movable blade up and down, left and right, or rotating relative to the fixed blade. Each of the master conveying roller pairs 38 and 39 has a driving roller rotatably supported on a side plate (not shown) of the plate making unit 3 and a driven roller pressed against the driving roller. The platen roller 35 is made by the thermal head 36. The master 40 transported by the above is transported downstream.

  A paper feed unit 4 is disposed on the right side of the printing unit 2 and below the plate making unit 3. The paper feed unit 4 includes a paper feed tray 42, a paper feed roller 43, a separation roller pair 44, a registration roller pair 45, and the like.

  A housing-like sheet feeding tray 42 on which a large number of sheets P can be stacked is supported by the apparatus main body 8 so as to be movable up and down, and is moved up and down by lifting means (not shown). A pair of side fences 46 are arranged on the upper surface of the paper feed tray 42 to align the paper P in the width direction. The side fences 46 are synchronized with each other by a known rack and pinion mechanism in the width direction of the paper P. It is comprised so that contact / separation is possible from an end surface. A plurality of paper size detection sensors 47 that detect the size of the stacked paper P are disposed inside the paper feed tray 42.

  Above the left end of the paper feed tray 42, a paper feed roller 43 having a high friction coefficient member on the surface is disposed. The paper feed roller 43 is rotatably supported by a bracket (not shown) provided so as to be swingable about an axis of an upper separation roller 44a, which will be described later, and is fed with a predetermined pressure when the paper feed tray 42 is raised. The uppermost sheet P on the paper tray 42 is pressed against.

  A separation roller pair 44 is disposed on the left side of the paper feed roller 43. The separation roller pair 44 has an upper separation roller 44a and a lower separation roller 44b each having a high friction resistance member on the surface, and the upper separation roller 44a is rotationally driven by a stepping motor 48, and the rotational force is not shown. The paper feeding roller 43 is rotated by being transmitted by a timing belt or the like. The lower separation roller 44b is pressed against the upper roller with a predetermined pressing force by a biasing force of a biasing means (not shown), and is configured to be rotatable only in the same direction (counterclockwise direction) as the upper roller.

  A registration roller pair 45 having a driving roller and a driven roller is disposed on the left side of the separation roller pair 44. The driving roller is rotatably supported between side plates (not shown) of the apparatus main body 8, and a rotational driving force from a plate cylinder driving unit (not shown) is transmitted through a driving force transmission unit (not shown) such as a cam. It is driven to rotate in synchronization with the plate cylinder 9. The driven roller is rotatably supported between side plates (not shown) of the apparatus body 8 and is pressed against the driving roller with a predetermined pressing force by a biasing means (not shown).

  A plate discharging unit 5 is disposed on the upper left side of the printing unit 2. The plate discharging unit 5 has a well-known configuration including an upper plate discharging member, a lower plate discharging member, a plate discharging box, a compression plate, etc. (not shown), and transports the used master while peeling the used master from the outer peripheral surface of the plate cylinder 9. Then, after discarding it in the discharge box, it is compressed with a compression plate. Used masters stored in the reclaim box are discarded by the operator when the refill box is full.

  A paper discharge unit 6 is disposed below the plate discharge unit 5. The paper discharge unit 6 includes a peeling claw 49, a paper transport unit 50, a paper discharge tray 51, a blower unit 52 which is a characteristic part of the present invention, and the like. The base end of the peeling claw 49 is swingably supported by the apparatus main body 8, and the free end formed into an acute angle is swung by a claw swinging means (not shown) so that the outer periphery of the plate cylinder 9 The plate cylinder 9 so that the separation position where the sheet P is peeled off from the outer peripheral surface of the plate cylinder 9 in the vicinity of the surface and the free end does not interfere with members such as the clamper 11 disposed on the outer peripheral surface of the plate cylinder 9. Selectively occupying a separation position separated from the outer peripheral surface.

  The sheet conveying means 50 is composed of a conveyor having a driving roller, a driven roller, an endless belt, a suction fan, and the like. Transport to the direction. The paper transport means 50 is provided with a pair of jump plates 55 (see FIG. 2) that sits against the paper P discharged to the paper discharge tray 51. A paper discharge tray 51 on which a large number of printed sheets P transported by the sheet transport means 50 are stacked has one end fence 53 and a pair of side fences 54 for aligning the sheets P on the upper surface thereof. ing.

  As shown in FIGS. 2 and 4, the air blowing means 52 includes a housing 57 having an air blowing fan 56 driven by a driving means (not shown), an opening / closing member 58, an arm member 59, and the like.

  The casing 57 having one end opened has an open end formed in a tapered shape, and an air blowing port 57a is formed. Holes 57b and 57c are formed in both side plates of the housing 57, and a shaft 60 is inserted into each of the holes 57b and 57c. Both ends of the shaft 60 are rotatably supported by bearing members 62 and 63 provided on a pedestal 61 (shown only in FIG. 4) fixed to the bottom surface of the housing 57. Is attached with an opening / closing member 58 formed slightly smaller than the inner cross section of the casing 57. A torsion coil spring 64 is attached in the vicinity of one end of the shaft 60 to which the rotating arm 67 is attached at one end, and a rotational biasing force in the clockwise direction in FIG.

  A stopper 65 is formed integrally with the inside of the housing 57 on the rotation path of the opening / closing member 58, and the rotation of the opening / closing member 58 is restricted. When the opening / closing member 58 abuts against the stopper 65, the opening / closing member 58 occupies a closed position in which the passage of the air flow sent from the blower fan 56 is closed. A discharge port 57d having an opening area smaller than that of the opening / closing member 58 is formed on the bottom surface of the casing 57, and the discharge port 57d has a bottom surface of the casing 57 as shown by a two-dot chain line in FIG. It is formed at a position that is closed by the opening / closing member 58 when it occupies the open position that has fallen to the side.

  A buffer member 66 made of an elastic material such as sponge is provided around the discharge port 57d, and the discharge port 57d is completely closed by the opening / closing member 58 when the opening / closing member 58 occupies the open position. Has been. The casing 57 is attached to the apparatus main body 8 in such a manner that the air blowing port 57 a faces the contact portion between the plate cylinder 9 and the press roller 10, and the discharge port 57 d faces the upper surface of the sheet conveying means 50.

  An arm member 59 is disposed in the vicinity of the casing 57. One end of the arm member 59 is rotatably supported by the support body 68 on the apparatus main body 8, and a roller 69 is attached to the other end, and a cam follower 70 is rotatably attached to the middle. The arm member 59 is disposed at a position where the roller 69 can come into contact with the rotating arm 67 and the cam follower 70 can come into contact with the peripheral surface of the printing pressure cam 23, and one end is fixed to the apparatus body 8 at the other end. The other end of the tension spring 71 is attached.

  With the above-described configuration, the arm member 59 always causes the cam follower 70 to abut against the circumferential surface of the printing pressure cam 23 by the urging force of the tension spring 71, and when the cam follower 70 abuts against the small diameter portion 23 b, When the cam follower 70 comes into contact with the large-diameter portion 23a, the surface of the roller 69 is brought into contact with the turning arm 67 so that the turning arm 67 is biased by the torsion coil spring 64. Against this, it is moved to the position shown by the two-dot chain line in FIG. Thereby, the opening / closing member 58 interlocked with the rotating arm 67 occupies a closed position when the cam follower 70 contacts the small diameter portion 23b, and occupies an open position when the cam follower 70 contacts the large diameter portion 23a. In the configuration described above, the opening / closing means 86 is constituted by the printing pressure cam 23, the arm member 59, the rotating arm 67, and the like.

  Here, the operation timing of each arm member 17 and arm member 59 will be described. As described above, each arm member 17 swings to bring the press roller 10 into and out of contact with the outer peripheral surface of the plate cylinder 9, and the arm member 59 functions to position the opening / closing member 58 between the open position and the closed position. Each of them is rocked by a common printing cam 23. In the present invention, as shown in FIG. 2, when the peripheral surface of the press roller 10 is in pressure contact with the outer peripheral surface of the plate cylinder 9 and a gap is generated between the cam follower 19 and the small diameter portion 23b, the press roller 10 contacts the small diameter portion 23b. The cam follower 70 that has been provided is determined so as to be located at a site where the cam follower 70 is about to climb onto the ascending surface of the printing pressure cam 23 toward the large-diameter portion 23a.

  With this configuration, the cam follower 70 has a large-diameter portion after the air flow from the blower fan 56, which is restricted from flowing out of the blower port 57 a by the opening / closing member 58 occupying the closed position, is pressed against the plate cylinder 9 by the press roller 10. When the opening / closing member 58 moves from the closed position to the open position in a short time by suddenly climbing on 23 a, it is rapidly blown from the air blowing port 57 a and cooperates with the peeling claw 49 from the outer peripheral surface of the plate cylinder 9. A peeling operation for peeling the printed paper P is performed.

  An image reading unit 7 is disposed on the upper part of the apparatus main body 8. The image reading unit 7 includes a contact glass 72 on which a document is placed, a pressure plate 73 that can be moved toward and away from the contact glass 72, a scanning unit 74 that scans and reads a document image, a lens 75 that focuses the scanned image, and a focus. An image sensor 76 such as a CCD for processing the obtained image is provided. Above the pressure plate 73, an ADF unit 77 used for automatically and continuously reading a plurality of documents is disposed.

Based on the above configuration, the operation of the stencil printing apparatus 1 will be described below.
After an original is placed on the contact glass 72 by the operator, when a plate making start key (not shown) on an operation panel (not shown) is pressed with the pressure plate 73 closed, the image reading unit 7 reads the original image. Done. The image is read by scanning the document image with the scanning unit 74, and the read image is focused by the lens 75 and then sent to the image sensor 76.

  In parallel with the image reading operation, the plate discharging unit 5 performs a plate discharging operation for peeling the used master 40 from the outer peripheral surface of the plate cylinder 9. When the plate making start key is pressed, the plate cylinder 9 starts to rotate and stops at a predetermined plate discharging position. After that, the clamper 11 is opened, and a plate removal member (not shown) is operated to scoop up the used master 40 from the outer peripheral surface of the plate cylinder 9, and then the plate cylinder 9 is rotated and the plate removal member is activated to use the master. The master 40 is stored in a discharge box (not shown). Thereafter, the plate cylinder 9 rotates to the plate feeding start position and stops, the clamper 11 is released, and the stencil printing apparatus 1 enters a plate feeding standby state.

  When the stencil printing apparatus 1 enters the plate feeding standby state, the platen roller 35 and each of the master transport roller pairs 38 and 39 are driven to rotate, and the master 40 is pulled out from the master roll 40a. The drawn master 40 is perforated according to the image data when passing through the thermal head 36, and a plate-making image is formed on the surface of the thermoplastic resin film. The master 40 is sent to the clamper 11 while making a plate, and when the leading end of the master 40 is transported to a position where it can be held by the clamper 11, the clamper 11 is closed. It is held on the outer peripheral surface.

  Thereafter, the plate cylinder 9 is rotationally driven at the same peripheral speed as the conveying speed of the master 40, and the winding operation of the master 40 around the plate cylinder 9 is performed. When the master 40 for one plate is made, the operations of the platen roller 35 and each of the master transport roller pairs 38 and 39 are stopped, and the master cutting means 37 is operated to cut the master 40. The cut master 40 is pulled out from the plate making section 3 by the rotation of the plate cylinder 9, and the plate making operation and the plate feeding operation are completed when the plate cylinder 9 occupies the home position.

  When the plate feeding operation is completed, the plate cylinder 9 starts to rotate in the clockwise direction in FIG. 1 at a low speed, and the upper separation roller 44a and the sheet feeding roller 43 are operated to place the uppermost sheet on the sheet feeding tray 42. One P is pulled out. At this time, the printing cam 23 is rotationally driven in synchronism with the rotational operation of the plate cylinder 9, and the solenoid 31 is turned on to swing the arm stopper 25, whereby the engagement corner 17d and the engagement protrusion 25e are engaged. The combined state is released. Further, the blower fan 56 is activated. The drawn paper P is temporarily stopped by the registration roller pair 45, and then the image area leading end in the plate cylinder rotation direction of the master 40 wound around the plate cylinder 9 reaches a contact portion with the press roller 10. When the registration roller pair 45 is rotationally driven at the timing, it is fed toward the contact portion between the plate cylinder 9 and the press roller 10.

  Slightly after the operation of the registration roller pair 45, the press roller 10 is pressed to the press contact position by the biasing force of the printing pressure spring 21 by releasing the contact between the large diameter portion 23 a of the rotating printing pressure cam 23 and the cam follower 19. And the fed paper P is pressed against the master 40 on the plate cylinder 9. By this pressing operation, the press roller 10, the paper P, the master 40, and the plate cylinder 9 are in pressure contact, and the ink supplied to the inner peripheral surface of the plate cylinder 9 by the ink roller 14 oozes out from a plate cylinder opening portion (not shown). After being filled in the porous support of the master 40, it is transferred to the paper P through the perforated portion of the master 40, and so-called printing is performed.

  The sheet P on which the image has been transferred by printing is peeled off from the outer peripheral surface of the plate cylinder 9 by the peeling claw 49 and the air blowing means 52, dropped downward and sent to the sheet conveying means 50, and then the sheet conveying means. The sheet is sucked and conveyed by the sheet 50 and discharged onto the sheet discharge tray 51. Thereafter, the plate cylinder 9 is rotated to the home position again and stopped, the solenoid 31 is turned off and the press roller 10 is held at the separated position, and the stencil printing apparatus 1 enters a printing standby state after finishing the plate-forming operation.

  After the stencil printing apparatus 1 is in a printing standby state, when a printing condition is input by a key on an operation panel (not shown) and then a test printing key (not shown) is pressed, the printing cylinder 9 is set in accordance with the set printing speed. At the same time, the sheet P is rotated and fed, and only one sheet P is fed from the sheet feeding unit 4, and a test printing is performed in the same manner as in the plate printing. When the image position, image density, and the like are confirmed by trial printing and the print start key (not shown) is pressed after the number of prints is set on the operation panel (not shown), the paper P is continuously fed from the paper supply unit 4. Then, the printing operation is performed in the same manner as in the trial printing. When the set number of prints is consumed, the plate cylinder 9 stops at the home position, and the stencil printing apparatus 1 enters the print standby state again.

  At the time of printing, trial printing, and printing described above, the press roller 10 presses the paper P against the plate cylinder 9, and the leading end of the paper P is held at the contact portion between the plate cylinder 9 and the press roller 10. After that, since the opening / closing member 58 occupies the open position, the air flow from the blower fan 56 is sent between the master 40 which has been made on the outer peripheral surface of the plate cylinder 9 and the leading end of the paper P. Then, the leading edge of the paper P is prevented from moving up and down violently by the air flow from the air blowing means 52, and the plate cylinder is prevented while the occurrence of image position shift, blurring image, paper folding, paper wrinkle and the like due to this is prevented. The sheet P can be satisfactorily peeled from the outer peripheral surface 9.

  Further, when the opening / closing member 58 occupies the closed position, the discharge port 57d is opened, and the air flow from the blower fan 56 is sent toward the upper surface of the paper conveying means 50 in this embodiment. After the vicinity of the leading edge is peeled off from the master 40 on the plate cylinder 9, the air flow from the discharge port 57 d acts to press the paper P against the paper transport means 50 when the paper P is sucked and transported to the paper transport means 50. In the conventional paper conveying means, it is possible to prevent the suction conveying force from being lowered due to the gradual decrease in the suction area as the trailing edge of the paper P passes through the suction conveying portion of the paper conveying means. Since the sheet can be seated to the rear end of the sheet in cooperation with the jump plate 55, the sheet P can be stably conveyed to the sheet discharge tray 51. Thereby, the alignment of the paper P on the paper discharge tray 51 is also improved. This effect is particularly effective for a thick sheet or a sheet having a short length in the sheet conveyance direction because the suction conveyance force by the sheet conveyance unit is weak from the beginning or the timing at which it weakens easily.

  In the first embodiment, since the air blowing by the air blowing means 52 is performed only in the vicinity of the front end of the paper P, the plate-making image formed on the master 40 is the rear side, that is, the plate-making master 40 is the outer periphery of the plate cylinder 9. When a portion having a high image density, such as a solid image portion, is wound on the rear end side of the image area when wound on the surface, the blowing from the blowing unit 52 is not performed at the portion having a high image density, and the sheet P is not printed. The image density is increased by sticking to the part where the image density of the master 40 is high and winding up, or when the paper P is peeled off from the part where the image density of the master 40 is high and the amount of ink adhesion increases. There is a problem that it becomes dark.

  An embodiment that solves the above-described problem will be described below as a second embodiment. In the second embodiment, the opening / closing member 58 is not opened / closed by swinging the arm member 59 by the printing cam 23, and the opening / closing member 58 is opened / closed using the dedicated swing cam 78 shown in FIG. Perform the action. The printing pressure cam 23 is used only for the swinging operation of the press roller 10, and the swinging cam 78, the arm member 59, the rotating arm 67, and the like constitute an opening / closing means.

  The swing cam 78 has two cams 78a and 78b. The cam 78a is fixed on the support shaft 23c of the printing pressure cam 23, and the cam 78b is rotatably supported on the support shaft 23c. ing. The cam 78a has two taps (not shown) formed at symmetrical positions around the support shaft 23c, and the cam 78b has two elongated holes 78c corresponding to the taps. The cam 78a is formed on the support shaft 23c so that the corner 78d has the same shape as the corner 23d (see FIG. 2) of the printing cam 23 and at the same position in the axial direction. The cam 78b is fixed to the cam 78a by two screws 78e.

  With the above-described configuration, the swing cam 78 can displace the opening / closing member 58 from the closed position to the open position at the same timing as in the first embodiment, and can also be shaken by loosening each screw 78e and shifting the cam 78b. The large-diameter portion of the moving cam 78, that is, the ratio of the opening / closing member 58 occupying the open position can be changed. For example, there is a portion having a high image density such as a solid image in the latter half of the plate-making image formed on the master 40. In this case, the cam 78b is shifted and fixed with the screws 78e so that the large-diameter portion becomes large, so that the above-described problems such as winding up or increase in image density can be prevented.

  FIG. 6 shows a blowing means 79 adopting the third embodiment of the present invention. Compared with the air blowing means 52 shown in the first embodiment, the air blowing means 79 is only in that a housing 80 having an air blowing fan (not shown) similar to the air blowing fan 56 inside is used instead of the housing 57. They are different and the other configurations are the same.

  The casing 80 having one end opened has an open end formed in a tapered shape, and an air outlet (not shown) similar to the air outlet 57a is formed. Both side plates of the housing 80 are formed with holes (not shown) similar to the holes 57 b and 57 c, and shafts (not shown) similar to the shaft 60 are inserted into the holes. Both ends of a shaft (not shown) are rotatably supported by a pedestal (not shown) similar to the pedestal 61 fixed to the bottom surface of the casing 80, and an opening / closing member (not shown) similar to the opening / closing member 58 is attached in the middle. ing. An arm member (not shown) similar to the arm member 59 is disposed in the vicinity of the housing 80, and the arm member (not shown) is swung by the printing cam 23 so that the opening / closing member (not shown) is a blower port (not shown). An open position for opening and a closed position for closing an air outlet (not shown) are selectively occupied.

  A pair of slide guides 81a and 81b are attached to the bottom surface of the housing 80, and the shielding plate 82 is movable in the paper width direction orthogonal to the paper conveyance direction which is the left-right direction in FIG. 6 by the slide guides 81a and 81b. It is supported by. A rack 82a is formed on one side edge of the shielding plate 82, and a small-diameter gear 83a rotatably supported by the housing 80 is engaged with the rack 82a. The small-diameter gear 83a integrally has a large-diameter gear 83b on the same axis, and the large-diameter gear 83b is attached to the output shaft of a stepping motor 84 that is an outlet opening / closing means attached to the housing 80. The pinion 84a is engaged. In FIG. 6, reference numeral 85 denotes a home position sensor that detects the home position of the shielding plate 82.

  Three holes 82b, 82c, and 82d are formed in the shielding plate 82 along the paper width direction, and three holes 80a that are discharge ports along the paper width direction are formed on the bottom surface of the housing 80. , 80b, 80c are formed. Each hole 80a, 80b, 80c is formed slightly smaller than each hole 82b, 82c, 82d, and the interval between the holes 82b, 82d is equal to the interval between the holes 80a, 80c. 82b and 82c are formed so that the interval between the holes 80a and 80b is different.

  With the above configuration, when the shielding plate 82 occupies the home position, the holes 80a, 80b, and 80c are shielded by the shielding plate 82 as shown in FIG. When an opening / closing member (not shown) occupies the open position, it flows out of the casing 80 only from an air outlet (not shown). When the paper P reaches the paper transport means 50, an opening / closing member (not shown) occupies the closed position. Next, the stepping motor 84 operates from the state shown in FIG. 6, and the shielding plate 82 occupies the first position so that the holes 80a and 82b and the holes 80c and 82d communicate with each other as shown in FIG. Then, an air flow from a blower fan (not shown) flows out of the housing 80 through the holes 80a and 82b and the holes 80c and 82d. Further, when the shielding plate 82 occupies the second position so that the holes 80b and 82c communicate with each other as shown in FIG. 8 by the operation of the stepping motor 84, the air flow from the blower fan (not shown) flows to the holes 80b. , 82c to the outside of the housing 80.

  With the above-described configuration, when there is a high image density portion such as a solid image on the plate-making image formed on the master 40, there is a high image density portion in which portion of the master 40 from the operation signal to the thermal head 36. When the high image density portion is on the rear side of the image area, the shielding plate 82 is positioned at the home position to block the holes 80a, 80b, and 80c, and the air flow discharged from the blower port The discharge period can be lengthened, and the above-described problems such as roll-up or increase in image density can be prevented.

  In the above-described configuration, for example, when the sheet conveying unit 50 has three endless belts and the stencil printing apparatus 1 can print from a postcard size to an A3 size, a large size such as a B4 size or an A3 size is used. By moving the shielding plate 82 to the first position when printing paper, and moving the shielding plate 82 to the second position when printing small-size paper such as postcard size or B5 size, the paper is conveyed when printing large-size paper. The paper can be pressed against the endless belt located at both ends of the means 50 by the air flow from the holes 80a and 80c, and the air from the hole 80b can be applied to the endless belt located at the center of the paper conveying means 50 when printing on small size paper. The paper can be pressed by the flow, and any size paper can be transported satisfactorily. This can be combined with the movement control of the shielding plate 82 with respect to the above-described high image density portion.

  In the third embodiment, the holes 80a, 80b, and 80c are all the same size. However, in order to improve the straightness of conveyance of small-size paper, for example, only the hole 80b is enlarged or two holes 80b are provided. It may be provided. In this case, the shape and the number of the holes 82b, 82c, and 82d may be changed in accordance with the change of the holes 80a, 80b, and 80c.

  In the third embodiment, three endless belts provided in the sheet conveying unit 50 are provided and three holes 80a, 80b, and 80c are provided in the casing 80. The number is not limited to this, and the number of holes provided in the housing 80 may be adjusted according to the number of endless belts provided in the paper transport unit 50. In the third embodiment, the holes 80a, 80b, and 80c are provided in one line in the paper width direction. However, the holes 80a, 80b, and 80c are provided in a line in parallel with the paper conveyance direction. It is good also as a structure which provides each hole part 80a, 80b, 80c of a row | line | column.

  In the case where the holes 80a, 80b, and 80c are provided in parallel with the paper transport direction, the paper P is conveyed by the air flow from the front end to the rear end of the paper P at the timing when the paper P is transported to the paper transport means 50. In order to press P, it is also possible to devise the arrangement of the holes so that the holes can be opened sequentially from the hole located in the most upstream to the hole on the downstream side. In order to adjust the strength and range of the air flow between the upstream side and the downstream side, the size of each hole may be gradually increased or the number of holes may be increased.

1 is a schematic front view of a stencil printing apparatus adopting an embodiment of the present invention. It is the schematic explaining the contact / separation means and ventilation means which are used for the 1st Embodiment of this invention. It is the schematic for demonstrating the predetermined clearance gap between the engagement corner | angular part and engagement protrusion in one Embodiment of this invention. It is a schematic perspective view explaining the ventilation means used for the 1st Embodiment of this invention. It is the schematic which shows the rocking cam used for the 2nd Embodiment of this invention. It is the schematic which shows the state which the shielding board in the ventilation means used for the 3rd Embodiment of this invention occupied the home position. It is the schematic which shows the state which the shielding board in the ventilation means used for the 3rd Embodiment of this invention occupied the 1st position. It is the schematic which shows the state which the shielding board in the ventilation means used for the 3rd Embodiment of this invention occupied the 2nd position.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Stencil printing apparatus 9 Plate cylinder 10 Pressing means (press roller)
24 Contacting / Separating Means 40 Master 50 Paper Conveying Means 52, 79 Blower Means 56 Blower Fan 57, 80 Housing 57a Blower 57d Ejector 58 Opening / Closing Member 80a, 80b, 80c Ejector (Hole)
84 Discharge port opening / closing means (stepping motor)
86 Opening / closing means P Paper

Claims (10)

A plate cylinder on which a master having a plate-making image formed on an outer peripheral surface is wound, a pressing unit that is detachable from the outer peripheral surface and presses a sheet against the master, and the pressing unit is attached to the outer peripheral surface. and moving means for contacting and separating Te, the sheet subjected to air blowing to the contact portion between the sheet and the master have at the blowing means is separated from the master, the sheet relative to the outer peripheral surface by said pressing means In the stencil printing apparatus in which the air is blown by the blowing means after being pressed ,
The blower means includes a housing having a blower fan for blowing air, a blower port formed in the housing for directing an air flow from the blower fan toward the contact portion, and supported by the housing for the blower port. An opening / closing member that selectively occupies an open position that opens and a closed position that closes the air blowing port; and an opening / closing means that opens and closes the opening / closing member. The air blowing means is opened and closed in synchronization with the operation of the contact / separation means, and the air blowing means performs air blowing to the contact portion when the air opening opening occupies the open position, and the air opening and closing member opens The stencil printing apparatus is characterized in that the air blowing to the contact portion is stopped when the air blowing port is closed . In the stencil printing apparatus according to claim 1,
The stencil printing apparatus, wherein the opening / closing means is configured to change a ratio of the opening / closing member occupying an open position during one contact / separation operation of the pressing member by the contact / separation means . In the stencil printing apparatus according to claim 1 or 2 ,
A stencil printing apparatus comprising an openable / closable discharge port for discharging the air flow from the inside of the casing . In the stencil printing apparatus according to claim 3 ,
A sheet conveying unit configured to convey a sheet peeled from the master; and the discharge port is disposed at a position for discharging the air flow toward the sheet conveying unit via the sheet peeled from the master. stencil printing apparatus characterized by there. In the stencil printing apparatus according to claim 3 or 4 ,
The discharge port is opened and closed by the opening and closing member, the discharge port is closed when the opening and closing member occupies the open position, and the discharge port is opened when the opening and closing member occupies the closed position. stencil printing apparatus characterized by that. In the stencil printing apparatus according to claim 3 or 4 ,
A first discharge port opening / closing unit configured to open and close the discharge port, wherein the first discharge port opening / closing unit closes the discharge port corresponding to a portion where the image density of the plate-making image is high. Stencil printing device. In the stencil printing apparatus according to claim 4 ,
A plurality of the discharge openings are provided in the width direction of the paper, and there are second discharge opening / closing means for individually opening and closing each discharge opening, and the second discharge opening / closing means corresponds to the width of the paper. The stencil printing apparatus is characterized by opening and closing each discharge port . In the stencil printing apparatus according to claim 4 ,
A plurality of the discharge ports are provided in the width direction of the sheet, and there are third discharge port opening / closing means for individually opening and closing each discharge port , and the third discharge port opening / closing means has an image density of the plate-making image. A stencil printing apparatus, wherein each discharge port is closed corresponding to a high part, and each discharge port is opened / closed corresponding to the size of the paper . In the stencil printing apparatus according to claim 4 ,
A plurality of discharge ports provided in the transport direction of the paper; a fourth discharge port opening / closing means for individually opening and closing each of the discharge ports; and a paper length detection means for detecting in advance the length of the paper in the transport direction. The fourth discharge port opening / closing means sequentially opens the discharge ports from the discharge port at the most upstream position in the paper transport direction toward the leading edge of the paper transported based on the detection result of the paper length detection means. A stencil printing apparatus that opens and finally opens only the discharge port at the most downstream position in the paper transport direction toward the rear end of the paper . In the stencil printing apparatus according to claim 9 ,
A plurality of the discharge ports are provided in a plurality of rows in the conveyance direction of the paper and in a plurality of rows in the width direction of the paper, and a fifth discharge port opening / closing means for individually opening and closing each discharge port, and a length in the conveyance direction of the paper And a fifth discharge port opening / closing unit that opens and closes each discharge port in accordance with the image density of the plate-making image, the width and the length of the sheet, and the like. Stencil printing device.

Images