JP4897326B2 - Stencil printing machine - Google Patents

Description

  The present invention relates to a stencil printing apparatus, and more particularly to operation control of a pressing member holding unit that holds a pressing member that presses a sheet against a plate cylinder at a separated position.

  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 perforated image based on the image information is hot-melt perforated and engraved on the master thermoplastic resin film by conveying with a conveying means, the perforated master is wound around a porous cylindrical plate cylinder and a press roller or the like By pressing the paper against the outer peripheral surface of the plate cylinder by the pressing means, the ink supplied to the inner peripheral surface of the plate cylinder by the ink supply means such as an ink roller is oozed out from the plate cylinder opening and the master perforation portion. A printed image is obtained on paper by transferring ink to the paper.

  As an example of a stencil printing apparatus for performing stencil printing, a press roller rotatably supported by a swingable press roller arm is used as a pressing means, and is provided on a cam and a press roller arm that rotate in synchronization with a plate cylinder. For example, “Patent Document 1” discloses a technique in which a press roller arm is swung by a cam follower to bring the press roller into and out of contact with a plate cylinder. In this technique, press roller locking means for holding the press roller in a state of being separated from the outer peripheral surface of the plate cylinder is provided in the vicinity of the press roller arm. A swingable printing pressure release claw member that can be engaged with a part of the press roller arm in a separated state separated from the outer peripheral surface of the cylinder, and a tension coil spring and a solenoid that swings the printing pressure release claw member Have.

Japanese Patent No. 2857558

  In the above technique, the printing pressure release claw member and the press roller arm are engaged with each other by the urging force of the tension coil spring at the time of non-printing so that the press roller does not come into contact with the outer peripheral surface of the plate cylinder at the time of non-printing. By holding the press roller in a separated state and operating the solenoid during printing, the engagement between the printing pressure release claw member and the press roller arm is released against the urging force of the tension coil spring, and the press roller arm cams So that the press roller can move toward and away from the outer peripheral surface of the plate cylinder.

However, in this configuration, it is necessary to always operate the solenoid during the printing operation, and there is a problem that the power consumption during the printing operation is increased.
SUMMARY OF THE INVENTION An object of the present invention is to provide a stencil printing apparatus that can solve the above-described problems and can save power by reducing power consumption.

The invention according to claim 1 is a plate cylinder, a swingable pressing member that presses a sheet against the plate cylinder, a swinging unit that swings the pressing member in synchronization with the rotation of the plate cylinder, A stencil printing apparatus having a pressing member holding means for holding the pressing member at a spaced position separated from the plate cylinder, the swinging means being rotatable in synchronization with the plate cylinder and having a large diameter portion; A cam having a small-diameter portion, a cam follower that contacts the cam and swings the pressing member, and the pressing member and the cam follower are rotatably supported, and the large-diameter portion contacts the cam follower. A swingable arm member that positions the pressing member in a separated position, and the pressing member holding means is displaceable so that it can be engaged with the arm member when the pressing member occupies the separated position. Engaging arm , And the engagement arm in the stencil printing machine having the arm displacing means for displacing the disengaged position not engaged with the arm member, when said arm displacing means for displacing the engagement arm to the disengaged position A solenoid having a first coil that is excited and a second coil that is excited when the engagement arm after displacement is held in a non-engagement position, and the large diameter during a printing operation on a first sheet. And the cam follower come into contact with each other and when the arm member and the engagement arm can be engaged, the first and second coils are excited to displace the engagement arm to the non-engagement position. Then, until the end of printing, only the second coil is excited to hold the engagement arm in the non-engagement position .

According to a second aspect of the present invention, in the stencil printing apparatus according to the first aspect of the present invention, the printing operation for the first sheet further includes a printing operation .

  According to the present invention, since the arm displacement means is operated and the engagement between the arm member and the engagement arm is prohibited only when the arm member and the engagement arm can be engaged, the operation time of the arm displacement means Can be suppressed to about 13 to 22% of the conventional value, and significant energy saving can be achieved.

FIG. 1 is a schematic front view of a stencil printing apparatus that employs an 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 provided at a position approximately at the center of the apparatus main body 8 and is driven to rotate in the clockwise direction in the drawing by a plate cylinder driving means (not shown), and is detachable from the outer peripheral surface of the plate cylinder 9. And a press roller 10 as a pressing member that presses the paper P fed from the paper feeding unit 4 against the plate cylinder 9.

  As shown in FIGS. 2 and 3, the plate cylinder 9 includes a porous support plate 9a having both side edges attached to the peripheral surfaces of a pair of end plates (not shown), and an outer peripheral surface of the porous support plate 9a. A mesh screen wound in multiple layers, and a pair of cams 9b attached to the outside of each end plate. As shown in FIG. 3, the porous support plate 9a is provided with an opening 9c having a plurality of openings and a non-opening 9d, and each cam 9b has an opening 9c as shown in FIGS. A large-diameter portion 9e having a larger diameter than the outer peripheral surface of the plate cylinder 9, that is, the outer peripheral surface of the porous support plate 9a, and a small-diameter portion 9f having a smaller diameter than the outer peripheral surface of the plate cylinder 9 are formed. A stage portion 11a and an openable / closable clamper 11b are disposed on the non-opening portion 9d. The clamper 11b is opened and closed by an opening / closing means (not shown) when the plate cylinder 9 occupies a predetermined position. Each large-diameter portion 9e is disposed at the position corresponding to the clamper 11b so as to have the same phase, and the protruding amount is set to be higher than the height of the clamper 11b.

An ink supply means 12 is disposed inside the plate cylinder 9. The ink supply unit 12 includes 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 inside of the plate cylinder 9 passes through the ink supply holes formed in the ink supply pipe 13 by the operation of the ink pump. To be 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. Synchronously, it is rotated in the clockwise direction in FIG. The ink roller 14 is disposed at a position where a slight gap is formed between the peripheral surface thereof and the plate cylinder 9, that is, the inner peripheral surface of the porous support plate 9a.

  A doctor roller 15 is disposed in the vicinity of the ink roller 14. The doctor roller 15 is also rotatably supported between side plates (not shown) similarly to the ink roller 14, and is rotated in the reverse direction in synchronization with the ink roller 14 by a 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 porous support plate 9a are in contact with each other, the ink is supplied to the inner peripheral surface of the porous support plate 9a.

  A press roller 10 is disposed below the plate cylinder 9. As shown in FIG. 2, the press roller 10 is supported by a pair of arm members 17 so that both ends of the support shaft are rotatable, and each 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.

  One end of each arm member 17 is fixed to a support shaft 18 that is rotatably supported by the apparatus main body 8, and is supported to be rotatable integrally with the apparatus main body 8. A press roller 10 having the same axial length as the width (axial length) of the porous support plate 9a is provided at substantially the center of each arm member 17 at both ends of the support shaft via the bearing member 19, respectively. It is supported rotatably. The press roller 10 has a well-known configuration in which a flexible elastic body such as rubber is wound around a core portion having a support shaft. The press roller 10 is coaxial between both side end surfaces and the respective bearing members 19 and includes the cams 9b. Cam followers 20 made of a resin material having a smaller diameter than the diameter are rotatably supported at the corresponding positions. The other ends of the tension springs 21 having one ends fixed to the apparatus main body 8 are respectively attached to lower ends of the respective arm members 17, and each arm member 17 is rotated in the clockwise direction in FIG. 4 about the support shaft 18. The rotational urging force is applied. Further, a locking claw 17 a is formed on the other end side of the one arm member 17.

  In the above-described configuration, the press roller 10 is swung in synchronization with the rotation of the plate cylinder 9 by the cams 9b, the arm members 17, the support shafts 18, the bearing members 19, the cam followers 20, and the tension springs 21. A rocking means 22 for contacting and separating from the outer peripheral surface of the plate cylinder 9 is configured. According to the swinging means 22, when the plate cylinder 9 rotates and the clamper 11b provided on the peripheral surface reaches a position corresponding to the press roller 10, the large diameter portion 9e provided in each cam 9b. 4 abuts against each cam follower 20, thereby swinging each arm member 17 about the support shaft 18 counterclockwise in FIG. 4 against the urging force of each tension spring 21, and pressing the press roller 10 with the clamper 11 b. Without being interfered with the outer periphery of the plate cylinder 9. When the plate cylinder 9 further rotates and the contact state between the top of each large-diameter portion 9e and each cam follower 20 is released, each arm member 17 is centered on the support shaft 18 by the urging force of each tension spring 21 as shown in FIG. And the peripheral surface of the press roller 10 comes into contact with the peripheral surface of the plate cylinder 9. Thereafter, when the plate cylinder 9 is further rotated and each small diameter portion 9f reaches a position corresponding to each cam follower 20, the contact state between each cam 9b and each cam follower 20 is released, and the press roller 10 is urged by the urging force of each tension spring 21. It occupies a press-contact position that presses against the peripheral surface of the plate cylinder 9.

  A pressing member holding means 23 for holding the press roller 10 in the separated position is disposed near the lower part of the swinging means 22. The pressing member holding means 23 includes a bracket 24, an engaging arm 25, a solenoid 26 as an arm displacing means, a tension spring 27, and the like.

  The bracket 24 is attached to the apparatus main body 8, and a support shaft 24a is implanted in the upper part thereof. The engagement arm 25 includes a locking portion 25a formed by bending a plate material into a substantially L shape and a support portion 25b formed by bending the plate material into a substantially U shape, and the support portion 25b supports both legs. The shaft 24a is rotatably supported, and one surface of the locking portion 25a is screwed to the tip of one leg portion of the support portion 25b so that the position can be adjusted. The other portion of the locking portion 25a is disposed opposite to the locking claw 17a, and an engagement hole 25c into which the locking claw 17a can be fitted is provided in the middle.

  The solenoid 26 is attached to the bracket 24, and the plunger 26a is rotatably attached to the end of the other leg of the support portion 25b. One end of the tension spring 27 is attached to the bracket 24, and the other end is attached near the bent portion of the support portion 25b. With this configuration, the engaging arm 25 is given a rotational biasing force in the clockwise direction in FIG. 4 about the support shaft 24a.

  Here, the position adjustment of the locking portion 25a with respect to the support portion 25b will be described. When the solenoid 26 is in an inoperative state and the engaging arm 25 is biased by the tension spring 27, the locking portion 25a is such that the small diameter portion 9f of each cam 9b and each cam follower 20 face each other, and the press roller 10 When the peripheral surface of the plate 9 is pressed against the peripheral surface of the plate cylinder 9, the flat portion 25d positioned above the engagement hole 25c comes into contact with the tip of the locking claw 17a, and the large-diameter portion 9e of each cam 9b When the press follower 20 comes into contact with the cam follower 20 and the press roller 10 is separated from the plate cylinder 9, it is disposed at a position where the locking claw 17a is fitted into the engagement hole 25c. Further, as shown in FIG. A gap α is formed between the upper end of the locking claw 17a and the upper portion of the engagement hole 25c within an angle β centered on the top of the engagement claw 17a so that the engagement claw 17a can be fitted into the engagement hole 25c. It is adjusted to become. In the present embodiment, the angle β is set to be 20 degrees. Reference numeral 9g in FIG. 5 indicates a starting point at which the gap α starts to occur when the plate cylinder 9 rotates in the clockwise direction in the figure, and reference numeral 9h indicates an end point at which the clearance α disappears.

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 28, a platen roller 29, a thermal head 30, a master cutting unit 31, a master transport roller pair 32, 33, and the like.
The master storage means 28 is disposed between the side plates (not shown) of the plate making unit 3 and is a master roll 34a formed by winding a master 34 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 29 is rotatably supported between side plates (not shown) of the plate making unit 3 and is rotationally driven by a stepping motor 35 provided in the apparatus main body 8. The thermal head 30 has a plurality of heat generating elements. The surface of the heat generating elements is brought into contact with the peripheral surface of the platen roller 29, and the thermoplastic resin film surface of the master 34 is heated, melted and punched. The thermal head 30 is pressed against the peripheral surface of the platen roller 29 with a predetermined pressing force by an urging means (not shown).

  The master cutting means 31 has a fixed blade and a movable blade, and has a known configuration in which the master 34 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 32 and 33 includes 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 plate is made by the thermal head 30 and is made by the platen roller 29. The transported master 34 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 36, a paper feed roller 37, a separation roller pair 38, a registration roller pair 39, and the like.
A casing-like sheet feeding tray 36 on which a large number of sheets P can be stacked on the upper surface is supported by the apparatus main body 8 so as to be movable up and down, and is moved up and down by a lifting means (not shown). A pair of side fences 40 are arranged on the upper surface of the paper feed tray 36 to align the paper P in the width direction. The side fences 40 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 and separation are possible. A plurality of paper size detection sensors 41 that detect the size of the stacked paper P are disposed inside the paper feed tray 36.

  Above the left end of the paper feed tray 36, a paper feed roller 37 having a high friction resistance member on the surface is disposed. The paper feed roller 37 is rotatably supported by a bracket (not shown) provided so as to be swingable about an axis of an upper separation roller 38a, which will be described later. The uppermost sheet P on the paper tray 36 is pressed against.

  A separation roller pair 38 is disposed on the left side of the paper feed roller 37. The separation roller pair 38 has an upper separation roller 38a and a lower separation roller 38b each having a high friction resistance member on the surface, and the upper separation roller 38a is rotationally driven by a stepping motor 42, and the rotational force is not shown. The paper feed roller 37 is rotated by being transmitted by a timing belt or the like. The lower separation roller 38b is pressed against the upper separation roller 38a 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 as the upper separation roller 38a.

  On the left side of the separation roller pair 38, a registration roller pair 39 having a driving roller 39a and a driven roller 39b is disposed. The driving roller 39a 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. The rotary drum 9 is driven to rotate in synchronization with the plate cylinder 9. The driven roller 39b is rotatably supported between side plates (not shown) of the apparatus body 8, and is pressed against the driving roller 39a 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 discharge unit 5 has a known configuration including an upper plate release member 43, a lower plate release member 44, a plate release box 45, a compression plate 46, and the like, and a master that has been used from the outer peripheral surface of the plate cylinder 9 by each plate release member 43, 44. 34 is transported while being peeled, and is discarded into the discharge box 45 and then compressed by the compression plate 46. The used master 34 stored in the discharge box 45 is discarded by the operator when the discharge box 45 is full.

A paper discharge unit 6 is disposed below the plate discharge unit 5. The paper discharge unit 6 includes a peeling claw 47, a paper transport unit 48, a paper discharge tray 49, and the like.
The base end of the peeling claw 47 is swingably supported by the apparatus main body 8 and is swung by a claw swinging means (not shown) so that the free end formed in an acute angle is the outer periphery of the plate cylinder 9. The plate cylinder 9 so that the separation position where the paper P is peeled off from the outer peripheral surface of the plate cylinder 9 near the surface and the free end does not interfere with members such as the clamper 11b disposed on the outer peripheral surface of the plate cylinder 9. Selectively occupying a separation position separated from the outer peripheral surface.

  The paper conveying means 48 is composed of a conveyor having a driving roller 48a, a driven roller 48b, an endless belt 48c, a suction fan 48d, etc., and sucks and conveys the paper P peeled off from the outer peripheral surface of the plate cylinder 9 by the peeling claw 47. In FIG. 1, it is conveyed to the left. A paper discharge tray 49 on which a large number of printed sheets P conveyed by the sheet conveying means 48 are stacked has one end fence 50 and a pair of side fences 51 for aligning the sheets P on the upper surface thereof. ing.

  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 52 on which a document is placed, a pressure plate 53 that can be moved toward and away from the contact glass 52, a scanning unit 54 that scans and reads a document image, a lens 55 that focuses the scanned image, and a focus. An image sensor 56 such as a CCD for processing the obtained image is provided. Above the pressure plate 53, an ADF unit 57 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 52 by an operator, when a plate making start key (not shown) on an operation panel (not shown) is pressed with the pressure plate 53 closed, the image reading unit 7 reads the original image. Done. The image is read by scanning the document image with the scanning unit 54, and the read image is focused by the lens 55 and then sent to the image sensor 56.

  In parallel with the image reading operation, the plate discharging unit 5 performs a plate discharging operation for peeling the used master 34 from the outer peripheral surface of the plate cylinder 9. In the state before this printing operation, the solenoid 26 is in an inoperative state, and the press roller 10 occupies the separated position by the large diameter portion 9e of each cam 9b coming into contact with each cam follower 20 at the end of the previous printing operation. At this time, the engaging claw 17a is fitted in the engaging hole 25c, and the press roller 10 is held at the separated position by the pressing member holding means 23 as shown in FIG. When a plate making start key (not shown) is pressed, the plate cylinder 9 starts to rotate and stops at a predetermined plate discharging position. Thereafter, the clamper 11b is opened, and the lower plate discharging member 44 is operated to scoop up the used master 34 from the outer peripheral surface of the plate cylinder 9, and then the plate cylinder 9 is rotated and each plate discharging member 43, 44 is operated. The used master 34 is stored in the discharge box 45. Thereafter, the plate cylinder 9 rotates to a predetermined plate feeding start position and stops, the clamper 11b is opened, and the stencil printing apparatus 1 enters a plate feeding standby state.

  When the stencil printing apparatus 1 enters a stencil supply standby state, the platen roller 29 and each of the master transport roller pairs 32 and 33 are driven to rotate, and the master 34 is pulled out from the master roll 34a. The drawn master 34 is perforated according to the image data when passing through the thermal head 30, and a plate-making image is formed on the surface of the thermoplastic resin film. The master 34 is sent to the printing unit 2 while making a plate, and when the leading end of the master 34 is transported to a position where it can be held by the clamper 11b, the clamper 11b 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 34, and the winding operation of the master 34 around the plate cylinder 9 is performed. When the master 34 for one plate is made, the operations of the platen roller 29 and each of the master transport roller pairs 32 and 33 are stopped, and the master cutting means 31 is operated to cut the master 34. The cut master 34 is pulled out from the plate making unit 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 sheet feeding roller 37 and the upper separation roller 38a rotate to rotate the uppermost sheet from the sheet feeding tray 36. One P is pulled out. As the plate cylinder 9 rotates, the cam 9b integrated therewith also rotates. When the plate cylinder 9 rotates to a position where the starting point 9g contacts the cam follower 20, as shown in FIG. Is swung counterclockwise about the support shaft 24a, and the engagement state between the locking claw 17a and the engagement hole 25c is released. At this time, since a predetermined time is required until the suction operation of the plunger 26a is completed after the solenoid 26 receives the operation command, the operation start timing of the solenoid 26 is a predetermined time than the timing at which the start point 9g contacts the cam follower 20. (For example, 40 to 50 msec, which varies depending on the rotational peripheral speed of the plate cylinder 9). Thereafter, when the plate cylinder 9 further rotates and the contact position of the cam 9b with the cam follower 20 exceeds the top of the large diameter portion 9e and passes through the end point 9h, the solenoid 26 is turned off and the engagement arm 25 is moved to the tension spring 27. Is oscillated clockwise around the support shaft 24a. At this time, the clearance α between the upper end of the locking claw 17a and the upper portion of the engagement hole 25c disappears, so that the front end of the locking claw 17a comes into contact with the flat portion 25d, and the cam follower 20 The urging force is pressed against the peripheral surface of the cam 9b.

  After the drawn paper P is temporarily stopped by the registration roller pair 39, the image area leading end in the plate cylinder rotation direction of the master 34 wound around the plate cylinder 9 reaches a contact portion with the press roller 10. When the drive roller 39a is rotationally driven at the timing, the sheet is fed toward the contact portion between the plate cylinder 9 and the press roller 10. The press roller 10 occupies the pressure contact position by the urging force of the tension spring 21 by releasing the contact between the large diameter portion 9e of the rotating cam 9b and the cam follower 20 slightly after the operation of the drive roller 39a. The fed paper P is pressed against the master 34 on the plate cylinder 9. By this pressing operation, the press roller 10, the paper P, the master 34, and the porous support plate 9a constituting the plate cylinder 9 are pressed against each other, and the ink supplied to the inner peripheral surface of the porous support plate 9a by the ink roller 14 is opened. It exudes from the hole 9c, fills the porous support of the master 34, and then is transferred to the paper P through the perforated part of the master 34, so-called printing.

  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 47, dropped downward and sent to the sheet transport means 48, and then sucked and transported by the sheet transport means 48. Are discharged onto the paper discharge tray 49. Thereafter, the plate cylinder 9 rotates again to the home position and stops, and the stencil printing apparatus 1 enters a printing standby state after finishing the plate attaching operation. When the starting point 9g of the cam 9b passes the position facing the cam follower 20 when the plate cylinder 9 rotates to the home position, the tip of the locking claw 17a that has been slid downward on the flat surface portion 25d The press roller 10 is held by the pressing member holding means 23 in a state of being fitted in the engagement hole 25c and occupying the separated position.

  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.

  Even during the above-described test printing and printing operation, when the plate cylinder 9 rotates to the position where the starting point 9g of the cam 9b contacts the cam follower 20, the solenoid 26 is turned on and the engagement arm 25 is turned around the support shaft 24a. By swinging clockwise, the engagement state between the locking claw 17a and the engagement hole 25c is released. Also at this time, the operation start timing of the solenoid 26 is set to be a predetermined time earlier than the timing at which the start point 9g contacts the cam follower 20. Thereafter, the plate cylinder 9 further rotates, and when the end point 9h of the cam 9b passes the position where it contacts the cam follower 20, the solenoid 26 is turned off and the engagement arm 25 is centered on the support shaft 24a by the urging force of the tension spring 27. The cam follower 20 is oscillated clockwise, the tip of the locking claw 17a abuts against the flat surface portion 25d, and the cam follower 20 is pressed against the peripheral surface of the cam 9b by the urging force of the tension spring 21. When the starting point 9g of the cam 9b passes the position facing the cam follower 20 when the plate cylinder 9 rotates to the home position at the end of the trial printing or printing operation, the tip of the locking claw 17a is engaged. The press roller 10 is held by the pressing member holding means 23 in a state of being fitted in the hole 25c and occupying the separated position.

  According to the above-described configuration, during printing, the solenoid 26 is operated and pressed only within the range of the angle β (see FIG. 5, 20 degrees in the present embodiment) when the cam 9b rotates as the plate cylinder 9 rotates. By holding the roller 10 in the separated position, as shown in FIG. 8, the energization time for the solenoid 26 can be suppressed to about 13 to 22% of the prior art, and significant energy saving can be achieved. Further, energy saving can be further achieved by performing similar operation control at the time of printing and test printing. In this embodiment, an example in which the solenoid 26 is used as the arm displacing means for displacing the engaging arm 25 is shown. However, the arm displacing means is not limited to this, and an actuator that can displace the engaging arm 25 in a short time. Any device such as a stepping motor may be used.

  FIG. 9 is a circuit diagram of a solenoid as arm displacement means used in another embodiment of the present invention. This solenoid 58 has two coils 58a and 58b inside, and has a terminal 58A common to the coils 58a and 58b and terminals 58B and 58C for the coils 58a and 58b. Is used instead. The solenoid 58 has a low energization rate, the plunger suction coil 58a has an energization rate of, for example, about 15%, and the plunger holding coil 58b has an energization rate of 100%. A plunger (not shown) is connected to the support portion 25b in the same manner as the plunger 26a. The solenoid 58 excites both the coils 58a and 58b until the plunger attracting operation is completed, and after the plunger is attracted, only the coil 58b is relatively small. Excited with current to maintain the suction state.

  Generally, the solenoid has a characteristic that the suction force increases rapidly as the plunger stroke is closer to zero (the plunger is fully pulled), and the suction force increases or decreases in proportion to the square of the current value. That is, when the engagement arm 25 occupies the engagement position shown in FIG. 6 or FIG. 7, the plunger stroke is large, so that it is necessary to excite with a relatively large current to obtain a predetermined suction force. When the arm 25 occupies the non-engagement position shown in FIG. 4 or FIG. 5, the plunger stroke is almost zero, so that a predetermined suction force can be obtained with a relatively small current. Therefore, in the case of a solenoid having two general terminals, power is wasted by generating an unnecessarily large suction force while the engagement arm 25 is held in the non-engagement position, that is, during a printing operation. It will be.

  The solenoid 58 uses the above-mentioned solenoid characteristics in reverse, and is held during a printing operation in which the engaging arm 25 occupies the non-engaging position and the plunger stroke of the solenoid 58 becomes almost zero, increasing the suction force. The power saving is achieved by exciting only the coil 58b. In this case, it has been experimentally found that the electric power consumed by the coil 58b when the engaging arm 25 is held in the non-engaging position is about 60% of that of the solenoid 26.

  When this solenoid 58 is applied to the stencil printing apparatus 1, when printing on the first sheet P, each coil 58a is rotated when the plate cylinder 9 rotates to a position where the start point 9g contacts the cam follower 20 as shown in FIG. , 58b are excited, and the engagement arm 25 is displaced to the non-engagement position to release the engagement state between the locking claw 17a and the engagement hole 25c. At this time, since a predetermined time is required until the plunger attracting operation is completed after the coils 58a and 58b are excited, the excitation timing is a predetermined time (for example, 40 to 40) than the timing at which the start point 9g contacts the cam follower 20. 50 msec, which depends on the rotational peripheral speed of the plate cylinder 9). Thereafter, when the plate cylinder 9 further rotates and the contact position of the cam 9b with the cam follower 20 exceeds the top of the large-diameter portion 9e and passes the end point 9h, the excitation of the coil 58a is stopped and only the excitation of the coil 58b is performed. The engagement arm 25 is held in the non-engagement position. The cam follower 20 is pressed against the peripheral surface of the cam 9b by the urging force of the tension spring 21, and thereafter, the press roller 10 contacts and separates from the plate cylinder 9 according to the shape of the cam 9b.

  Then, when the end point 9h of the cam 9b passes through the position where it contacts the cam follower 20 during printing on the last sheet of paper P, the excitation of the coil 58b is stopped and the engagement arm 25 is displaced to the engagement position. Thereafter, when the plate cylinder 9 rotates to the home position at the end of the printing operation, if the start point 9g of the cam 9b passes the position facing the cam follower 20, the tip of the locking claw 17a is fitted into the engagement hole 25c. In addition, the press roller 10 is held by the pressing member holding means 23 in a state of occupying the separated position.

  According to the above-described configuration, the coils 58a and 58b are excited when the arm member 17 and the engagement arm 25 can be engaged during the printing operation for the first sheet P, and the coils are thereafter used until the end of printing. Since only 58b is excited and the engagement arm 25 is held in the non-engagement position, the excitation power of the coil 58a in the total number of printed sheets can be almost ignored as shown in FIG. 10, and the power consumption is determined by the excitation of the coil 58b. Therefore, energy saving can be achieved by saving about 40% of the power consumption compared to the prior art shown in FIG. According to the other embodiment, although the power saving effect is reduced as compared with the above-described embodiment, the solenoid is not operated every rotation of the plate cylinder 9, so that the noise is lower than that of the above-described embodiment. Generation | occurrence | production can be reduced and generation | occurrence | production of malfunctions, such as component abrasion by sliding with the latching claw 17a front-end | tip and the plane part 25d, can be prevented.

  In the other embodiments described above, the coils 58a and 58b are excited at the time of printing on the first sheet P during the printing operation, and thereafter only the coil 58b is excited. However, at the time of printing, the coils 58a and 58b are excited. 58b may be excited, and only the coil 58b may be excited during the subsequent test printing and printing operation, and each coil 58a, 58b may be excited during the test printing, and only the coil 58b may be excited during the subsequent printing operation. .

1 is a schematic front view of a stencil printing apparatus adopting an embodiment of the present invention. It is a schematic perspective view explaining the structure of the printing part used for one Embodiment of this invention. It is a schematic front view explaining the structure of the plate cylinder used for one Embodiment of this invention. It is a schematic front view of the printing part explaining the rocking | fluctuation means and press member holding means used for one Embodiment of this invention. It is a schematic front view of the printing part explaining the operation timing of the pressing member holding means in one embodiment of the present invention. It is a schematic front view of the printing part which shows the state which the engagement arm in one Embodiment of this invention occupied the engagement position. It is a schematic front view of the printing part for demonstrating operation | movement of the engagement arm in one Embodiment of this invention. It is a timing chart for comparing the operation timing of the arm displacement means in one embodiment of the present invention with the operation timing of the arm displacement means in the prior art. It is a circuit diagram of the solenoid as an arm displacement means used for other embodiment of this invention. It is a timing chart explaining the excitation timing of each coil in other embodiments of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Stencil printing apparatus 9 Plate cylinder 9b Cam 9e Large diameter part 9f Small diameter part 10 Press member (press roller)
17 Arm member 20 Cam follower 22 Oscillating means 23 Pressing member holding means 25 Engaging arms 26, 58 Arm displacement means (solenoid)
58a first coil 58b second coil P paper

Claims (2)

A plate cylinder, a swingable pressing member that presses a sheet against the plate cylinder, a swinging unit that swings the pressing member in synchronization with the rotation of the plate cylinder, and the pressing member spaced apart from the plate cylinder A stencil printing apparatus having a pressing member holding means for holding in the separated position, wherein the swinging means is rotatable in synchronization with the plate cylinder and has a large diameter portion and a small diameter portion, and A cam follower that contacts the cam and swings the pressing member, and rotatably supports the pressing member and the cam follower, and when the large diameter portion contacts the cam follower, the pressing member is moved to a separated position. A displaceable engagement arm having a swingable arm member to be positioned, wherein the pressing member holding means is engageable with the arm member when the pressing member occupies a separated position, and the engagement arm In a stencil printing machine having the arm displacing means for displacing the disengaged position not engaged with the arm member,
A first coil that is excited when the arm displacing means displaces the engaging arm to the non-engaging position and a second coil that is excited when holding the displaced engaging arm in the non-engaging position. A solenoid having a coil, and the first and second when the large-diameter portion and the cam follower come into contact with each other and the arm member and the engagement arm can be engaged during a printing operation on the first sheet. Each of the coils is excited to displace the engagement arm to the non-engagement position, and thereafter only the second coil is excited to hold the engagement arm in the non-engagement position until the end of printing. A stencil printing device. In the stencil printing apparatus according to claim 1,
The stencil printing apparatus, wherein the printing operation for the first sheet includes a plate printing operation .

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