JP2007055074A - Stencil printing equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide stencil printing equipment, which prevents troubles due to the drying or solidification of ink in an ink feeding port and an ink feeding passage and in an in recovering port and an ink recovering passage. <P>SOLUTION: The stencil printing equipment comprises a rotatable drum having an outer peripheral wall, which is made of an ink impermeable member and onto the surface of which the stencil paper is installed, an ink feeding means for feeding ink to the surface of the outer peripheral wall through the ink feeding port provided on the outer peripheral wall, a press roll for pressing a fed printing paper against the outer peripheral wall, and an ink recovering means for recovering the ink flowed outside out of the maximum printing area of the outer peripheral wall by sucking through the ink recovering port, wherein the residual ink is brought back to its container by driving the feeding pump of the ink feeding means in the direction opposite to the normal direction for feeding the ink and driving the recovering pump of the ink recovering means in its normal direction for recovering the ink when no following printing is executed after the elapse of the predetermined period of time since the finish of a printing action. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a stencil printing apparatus for transferring a printing medium while pressing the printing medium to a drum on which the stencil sheet is mounted, and transferring the ink that oozes out from the perforation of the stencil sheet to the printing medium.

  As the conventional stencil printing apparatus of this type, the present applicant has proposed that disclosed in Patent Document 1. The stencil printing device is rotatable and has a drum having an outer peripheral wall formed of an ink impermeable member, a base paper clamp portion provided on the outer peripheral wall for clamping the front end of the stencil base paper, and an ink on the outer peripheral wall. An ink supply means that has a supply port and supplies ink to the surface of the outer peripheral wall from the ink supply port, and is provided movably between a pressing position that presses against the outer peripheral wall and a standby position that is separated from the outer peripheral wall, A press roll that presses the fed printing paper against the outer peripheral wall, and an ink recovery means that has an ink recovery port downstream from the maximum printing area of the outer peripheral wall and recovers the ink that has flowed into the ink recovery port by suction. I have.

In this stencil printing apparatus, when the outer peripheral wall on which the stencil sheet is mounted is rotated and the printing paper is fed in a state where ink is supplied from the ink supply port to the surface of the outer peripheral wall, the printing paper Is conveyed while being pressed against the stencil sheet and the outer peripheral wall of the drum by the press roll, while the ink between the outer peripheral wall of the drum and the stencil sheet is diffused downstream in the printing direction while being pressed by the pressing force of the press roll. At the same time, the diffused ink oozes out from the perforation of the stencil sheet and is transferred to the printing paper side, and an ink image is printed on the printing paper. The ink supplied to the drum is held in a substantially sealed space between the outer peripheral wall of the drum and the stencil paper, and contact with the atmosphere is minimized, and various rolls for supplying ink are provided inside the drum. There is no need to place them. Therefore, the ink does not change even if printing is not performed for a long time, and the drum can be reduced in size and weight.
JP 2005-74734 A

  By the way, the ink supply means starts driving the supply pump immediately before the start of the printing operation to supply ink to the drum, and stops driving the supply pump at the end of the printing operation to stop ink supply to the drum. To do. The ink recovery means starts driving the recovery pump simultaneously with the start of the printing operation, enters an ink recovery state, and stops driving the recovery pump when the printing operation ends. Therefore, ink remains in the ink supply port and the ink supply path at the end of the printing operation. The residual ink gradually dries and solidifies over time even if the ink supply port is blocked by stencil paper. The reason for this is that, in an apparatus using an outer peripheral wall formed of an ink impermeable member, ink having a high drying speed is used, and air is circulated from the perforated stencil sheet to the ink supply port. .

  Therefore, if the time from the end of the printing operation to the start of the next printing is too long, the ink remaining in the ink supply port and the ink supply path is dried and solidified. When the ink dries or solidifies in the ink supply port or the ink supply path, it becomes difficult to supply a desired amount of ink during the next printing operation, which causes printing failure.

  Further, the ink drying and ink solidification described above also occur in the ink recovery port and the ink recovery path. When the ink is dried or solidified in the ink collection port or the ink collection path, the ink supply amount becomes excessive with respect to the ink collection amount, which causes ink leakage to the outside of the stencil sheet.

    Therefore, an object of the present invention is to provide a stencil printing apparatus that can prevent problems caused by ink drying and ink solidification in an ink supply port and an ink supply path. Another object of the present invention is to provide a stencil printing apparatus that can prevent problems due to ink drying and ink solidification in the ink recovery port and the ink recovery path.

  The invention according to claim 1, which achieves the above object, has a peripheral wall that is rotatable and formed of an ink-impermeable member, and a drum on which a stencil sheet is mounted on the surface of the peripheral wall; Stencil printing comprising an ink supply port on the wall, ink supply means for supplying ink to the surface of the outer peripheral wall from the ink supply port, and a press roll for pressing a fed print medium against the outer peripheral wall In the apparatus, when the next printing is not executed until a predetermined time has elapsed since the end of the printing operation, the supply pump of the ink supply means is driven in reverse to the ink supply.

  According to a second aspect of the present invention, there is provided a drum having an outer peripheral wall that is rotatable and formed of an ink impermeable member, a stencil sheet is mounted on the outer peripheral wall, and an ink supply port in the outer peripheral wall. An ink supply means for supplying ink to the surface of the outer peripheral wall from the ink supply port, a press roll for pressing a fed print medium against the outer peripheral wall, and an outer side of the maximum printing area of the outer peripheral wall. In the stencil printing apparatus provided with an ink collecting means for sucking and collecting the ink that has flowed out from the ink collecting port, the ink is printed when the next printing is not executed until a predetermined time has elapsed since the end of the printing operation. The recovery pump of the recovery means is driven to rotate forward.

  According to a third aspect of the present invention, there is provided a drum having an outer peripheral wall that is rotatable and formed of an ink impermeable member, a stencil sheet is mounted on the outer peripheral wall, and an ink supply port on the outer peripheral wall. An ink supply means for supplying ink to the surface of the outer peripheral wall from the ink supply port, a press roll for pressing a fed print medium against the outer peripheral wall, and an outer side of the maximum printing area of the outer peripheral wall. In the stencil printing apparatus provided with an ink collecting means for sucking and collecting the ink that has flowed out from the ink collecting port, the ink is printed when the next printing is not executed until a predetermined time has elapsed since the end of the printing operation. The supply pump of the supply means is driven to rotate backward with respect to the ink supply time, and the recovery pump of the ink recovery means is driven to rotate forward.

  Invention of Claim 4 is a stencil printing apparatus of any one of Claims 1-3, Comprising: The reverse rotation drive of the said supply pump or the normal rotation drive of the said recovery pump is the said outer peripheral wall surface. It is characterized in that the stencil sheet is mounted.

  According to the first aspect of the present invention, when a predetermined time elapses without executing the next printing from the end of the printing operation, the residual ink in the ink supply port or the ink supply path is sucked by the supply pump to the ink container side. Therefore, the residual ink does not dry or solidify in the ink supply port or the ink supply path. Accordingly, it is possible to prevent problems such as defective printing due to ink drying and ink solidification in the ink supply port and the ink supply path.

  According to the second aspect of the present invention, when a predetermined time has passed since the next printing has not been executed since the end of the printing operation, the residual ink in the ink recovery port and the ink recovery path is sucked by the recovery pump to the side of the recovery container. Therefore, the residual ink does not dry or solidify in the ink collection port or the ink collection path. Therefore, problems such as ink leakage due to ink drying and ink solidification in the ink collection port and the ink collection path can be prevented.

  According to the invention of claim 3, when a predetermined time elapses without the next printing being executed from the end of the printing operation, the residual ink in the ink supply port and the ink supply path is sucked by the supply pump to the ink container side. In addition, the residual ink in the ink recovery port and the ink recovery path is returned to the recovery container side by suction of the recovery pump, so that the residual ink in the ink supply port, the ink supply path, the ink recovery port, and the ink recovery path Does not dry or solidify. From the above, it is possible to prevent problems such as printing defects due to ink drying and ink solidification in the ink supply port and ink supply path, and also due to ink drying and ink solidification in the ink recovery port and ink recovery path. It is possible to prevent problems such as ink leakage.

  According to the fourth aspect of the present invention, the stencil sheet blocks the ink supply port and the ink recovery port, and the ink supply path and the ink recovery path are effectively depressurized by driving the supply pump and the recovery pump. It can be returned to the ink container side or the collection container side.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  1 to 7 show an embodiment of the present invention, FIG. 1 is a schematic configuration diagram of a stencil printing apparatus, FIG. 2 is a perspective view of a drum, and FIG. 3 is a cross-sectional view taken along line AA in FIG. 4 is a cross-sectional view taken along line BB in FIG. 2, FIG. 5 is a schematic view of the outer peripheral wall of the drum, FIG. 6 is a partial cross-sectional view for explaining the ink diffusion mechanism, and FIG. FIG.

  As shown in FIG. 1, the stencil printing apparatus mainly includes a document reading unit 1, a plate making unit 2, a printing unit 3, a paper feeding unit 4, a paper discharging unit 5, and a plate discharging unit 6. .

  The document reading unit 1 includes a document setting table 10 on which a document to be printed is placed, reflection-type document sensors 11 and 12 that detect the presence of documents on the document setting table 10, and documents on the document setting table 10. The document transport rolls 13 and 14 for transporting the document, the stepping motor 15 for rotationally driving the document transport rolls 13 and 14, and the image data of the document transported by the document transport rolls 13 and 14 are optically read and this is electrically read. It has a contact image sensor 16 that converts it into a signal, and a document discharge tray 17 on which a document discharged from the document setting table 10 is placed. Then, the document placed on the document setting table 10 is transported by the document transport rollers 13 and 14, and the image sensor 16 reads the image data of the transported document.

  The plate making unit 2 includes a base paper storage unit 19 that stores the rolled long stencil base paper 18, a thermal head 20 that is disposed downstream of the base paper storage unit 19, and a position opposite to the thermal head 20. A platen roll 21, a pair of base paper feed rolls 22, 22 arranged downstream of the transport of the platen roll 21 and the thermal head 20, a light pulse motor 23 that rotationally drives the platen roll 21 and the base paper feed roll 22, And a base paper cutter 24 disposed downstream of the pair of base paper feed rolls 22 and 22.

  Then, the long stencil sheet 18 is transported by the rotation of the platen roll 21 and the base paper feed roll 22, and each point-like heating element of the thermal head 20 selectively generates heat based on the image data read by the image sensor 16. Thus, the stencil sheet 18 is made by heat-sensitive perforation, and the stencil sheet 18 thus made is cut by a stencil sheet cutter 24 to produce a stencil sheet 18 having a predetermined length.

  The printing unit 3 includes a drum 26 having an outer peripheral wall 53 that rotates in the direction of arrow A in FIG. 1 by the driving force of the main motor 25, and a base paper clamping unit 27 that is provided on the outer peripheral wall 53 and clamps the leading end of the stencil base paper 18. Ink supply means 54 for supplying ink to the surface of the outer peripheral wall 53 and ink recovery means 73 for recovering excess ink on the surface of the outer peripheral wall 53 are provided.

  The printing unit 3 includes a base paper confirmation sensor 28 that detects whether or not the stencil paper 18 is wound around the outer peripheral surface of the drum 26, a reference position detection sensor 30 that detects the reference position of the drum 26, and a main motor. And a rotary encoder 31 for detecting 25 rotations. The rotational position of the drum 26 can be detected by detecting the output pulse of the rotary encoder 31 based on the detection output of the reference position detection sensor 30.

  Further, the printing unit 3 includes a press roll 35 disposed at a position below the drum 26. The press roll 35 is pressed against the outer peripheral surface of the drum 26 by the driving force of the solenoid device 36. It is configured to be able to change between a standby position separated from the outer peripheral surface. The press roll 35 is always positioned at the pressing position during the printing mode period (including the first print), and is positioned at the standby position during the period other than the printing mode.

  Then, the leading end of the stencil sheet 18 conveyed from the plate making unit 2 is clamped by the stencil sheet clamp unit 27, and the outer peripheral wall 53 of the drum 26 is rotated in this clamped state so that the stencil sheet 18 is wound around the outer peripheral wall 53 of the drum 26. The printing paper 37 is mounted by pressing a printing paper (printing medium) 37 that is mounted and fed from the paper feeding unit 4 in synchronization with the rotation of the drum 26 against the stencil paper 18 wound around the drum 26 by a press roll 35. The ink 56 is transferred from the perforation of the stencil sheet 18 to print an image.

  The paper feed unit 4 includes a paper feed tray 38 on which the print paper 37 is stacked, primary paper feed rolls 39 and 40 that transport only the uppermost print paper 37 from the paper feed base 38, and the primary paper feed. A pair of secondary paper feed rolls 41 and 41 for conveying the printing paper 37 conveyed by the rolls 39 and 40 between the drum 26 and the press roll 35 in synchronization with the rotation of the drum 26, and the pair of secondary paper feed rolls A paper feed sensor 42 that detects whether or not the printing paper 37 has been conveyed between 41 and 41. The primary feed rolls 39 and 40 are configured to selectively transmit the rotation of the main motor 25 via the feed clutch 43.

  The paper discharge unit 5 includes a paper separation claw 44 that separates the printed printing paper 37 from the drum 26, a conveyance path 45 through which the printing paper 37 separated from the drum 26 by the paper separation claw 44 is conveyed, And a paper discharge tray 46 on which the printing paper 37 discharged from the conveyance path 45 is placed.

  The plate discharging unit 6 guides the leading end of the stencil sheet 18 unclamped from the outer peripheral surface of the drum 26 and transports the guided used stencil sheet 18 while being peeled off from the drum 26, and this plate discharging transport. A stencil box 48 for storing the stencil sheet 18 conveyed by the means 47 and a stencil compression member 49 for pushing the stencil sheet 18 conveyed into the stencil box 48 by the stencil conveying means 47 into the stencil box 48 are provided. Have.

  Next, the configuration of the drum 26, the base paper clamp unit 27, the ink supply unit 54, and the ink collection unit 73 will be described.

  As shown in FIGS. 2 to 4, the drum 26 includes a pair of support shafts 50 fixed to the apparatus main body H (shown in FIG. 1) and a pair of shafts 50 rotatably supported by the support shafts 50 through respective bearings 51. Side discs 52 and 52, and a cylindrical outer peripheral wall 53 fixed between the pair of side discs 52 and 52. The outer peripheral wall 53 is integrally driven with the pair of side disks 52 and 52 by the rotational force of the main motor 25. The outer peripheral wall 53 is formed of an ink impermeable member that has rigidity and does not allow the ink 56 to pass therethrough. Further, the outer peripheral surface of the outer peripheral wall 53 is subjected to Teflon (registered trademark) processing to form a cylindrical surface having no unevenness.

  The base paper clamp portion 27 is provided by using a clamp recess 53 a formed along the axial direction of the support shaft 50 of the outer peripheral wall 53. One end of the base paper clamp portion 27 is rotatably supported by the outer peripheral wall 53 and protrudes from the outer peripheral wall 53 in the clamp release state indicated by the phantom line in FIG. 4, but in the clamped state indicated by the solid line in FIG. 53 so as not to protrude from 53. Therefore, the stencil paper clamping unit 27 can clamp the stencil paper 18 without protruding onto the outer peripheral wall 53.

  The outer peripheral wall 53 is rotated in the direction of arrow A in FIGS. 2 and 4, and the position where the outer peripheral wall 53 is slightly rotated from the base paper clamp portion 27 is the printing start point. Therefore, the rotation direction A becomes the printing direction M, and the area below the printing start point is the printing area. In the first embodiment, the maximum print area S (shown in FIG. 5) is set to an area capable of A3 size printing. An ink supply unit 55 of the ink supply means 54 is provided upstream of the maximum print area S of the outer peripheral wall 53 in the printing direction M.

  As shown in FIGS. 2 to 5, the ink supply means 54 is sucked by the ink container 57 in which the ink 56 is stored, the supply pump 58 that sucks the ink 56 in the ink container 57, and the supply pump 58. A first pipe 59 for supplying the ink 56, and a support shaft 50 to which the other end of the first pipe 59 is connected, an ink passage 60 is formed therein, and a hole 61 is formed at a position opposed to 180 degrees. A rotary joint 63 that is rotatably supported on the outer peripheral side of the support shaft 50 and has a communication hole 62 that can communicate with the hole 61, one end connected to the rotary joint 63, and the other end connected to the outer peripheral wall 53. The second pipe 64 is guided, and the ink supply unit 55 is opened at the other end of the second pipe 64.

  The ink supply unit 55 includes an ink diffusion groove 65 (shown in FIG. 3) that diffuses the ink 56 (shown in FIG. 6) from the second pipe 64 in the printing orthogonal direction N, and the printing orthogonal direction N of the ink diffusion groove 65. And an ink supply port 55 a having one end opened at a distance and the other end opened on the surface of the outer peripheral wall 53. The ink diffusion groove 65 and the ink supply port 55a are formed by disposing an ink distribution member 68 in a recess formed along the direction orthogonal to the printing direction M of the outer peripheral wall 53 (that is, the printing orthogonal direction N). Yes. The ink supply ports 55 a have a straight shape along the printing orthogonal direction N, and supply the ink 56 almost uniformly in the printing orthogonal direction N of the outer peripheral wall 53.

  As shown in FIGS. 2 to 5, the ink recovery means 73 includes an ink recovery port 72 disposed downstream of the maximum printing area S of the outer peripheral wall 53, and a third pipe 74 having one end opened at the ink recovery port 72. And the other end side of the third pipe 74 is connected to form a rotary joint 63 in which a communication hole 75 is formed, the rotary joint 63 is rotatably supported, and the communication hole 75 can be connected to the inside 76a and ink inside. A support shaft 50 in which a passage 76b is formed, a fourth pipe 77 having one end connected to the support shaft 50, and a recovery medium that is interposed in the middle of the fourth pipe 77 and sucks the ink 56 in the fourth pipe 77. A pump (for example, a trochoid pump) 78 and a recovery container 79 to which the other end of the fourth pipe 77 is connected are provided.

  The ink recovery port 72 is formed by disposing the pipe fixing member 82 in the concave portion 81 of the outer peripheral wall 53, and is continuously formed along the printing orthogonal direction N. The ink recovery port 72 communicates with side ink recovery grooves 71, 71 and a top ink recovery groove 90. The side ink collecting grooves 71 and 71 are continuously formed along the left and right outer positions in the printing orthogonal direction N from the maximum printing area S of the outer peripheral wall 53. The top ink collecting groove 90 is continuously formed along the printing orthogonal direction N at a printing upstream position further from the ink supply port 55a upstream from the maximum printing area S. That is, the ink collection port 72, the left and right ink collection grooves 71, 71, and the upstream ink collection groove 90 are arranged in a square shape so as to surround the entire maximum print area S.

  The rotary joint 63 is also used as the ink supply means 54. Since the support shaft 50 is also used in the ink passage of the ink supply means 54, it has a double pipe structure.

  Next, the operation of the stencil printing apparatus will be described based on the flow of FIG.

  First, when the plate making mode is selected, it is checked whether or not the stencil sheet 18 is mounted on the drum 26. If the stencil sheet 18 is mounted, the stencil removing operation for removing the stencil sheet 18 from the drum 26 is performed in parallel with the plate making operation (step S1). Details of the plate removal operation will be described later.

  Briefly explaining the plate making operation, the stencil sheet 18 is conveyed by the rotation of the platen roll 21 and the stencil feed roll 22, and a large number of heating elements of the thermal head 20 selectively generate heat based on the image data read by the document reading unit 1. By operating, the stencil sheet 18 is subjected to thermal perforation to make a plate. A predetermined portion of the stencil sheet 18 thus made is cut with a stencil sheet cutter 24 to produce a stencil sheet 18 having a desired size.

  The plate making operation is performed continuously to the plate making operation (step S2). That is, the front end of the stencil sheet 18 made by the plate making unit 2 is clamped by the stencil sheet clamp unit 27 of the drum 26, and the drum 26 is rotated in this clamped state so that the stencil sheet 18 is wound around the outer peripheral surface of the drum 26. To do.

  Next, first printing is performed (step S3). Details of the first print are the same as those in the next printing operation, and are therefore omitted.

  When the printing mode is selected after the plate making mode, the printing operation is started (step S4). Explaining the printing operation, the outer peripheral wall 53 of the drum 26 is driven to rotate, and the ink supply means 54 and the ink recovery means 73 are started to be driven. Then, the ink 56 is supplied to the outer peripheral wall 53 from the ink supply port 55a of the ink supply unit 55, and the supplied ink 56 is held between the outer peripheral wall 53 and the stencil sheet 18, and the press roll 35 is in the standby position. To the pressed position.

  In synchronization with the rotation of the drum 26, the paper feeding unit 4 feeds the printing paper 37 between the drum 26 and the press roll 35. The fed printing paper 37 is pressed against the outer peripheral wall 53 of the drum 26 by the press roll 35 and is conveyed by the rotation of the outer peripheral wall 53 of the drum 26. That is, the printing paper 37 is conveyed while being in close contact with the stencil sheet 18.

  In parallel with the conveyance of the printing paper 37, the ink 56 held between the outer peripheral wall 53 of the drum 26 and the stencil sheet 18 is squeezed by the pressing force of the press roll 35 as shown in FIG. While being diffused downstream in the printing direction M, the diffused ink oozes out from the perforations of the stencil sheet 18 and is transferred to the printing paper 37 side. Thereby, an ink image is printed on the printing paper 37 in the process of passing between the outer peripheral wall 53 of the drum 26 and the press roll 35. The printing paper 37 that has passed through between the outer peripheral wall 53 of the drum 26 and the press roll 35 is peeled off from the drum 26 by the paper separation claw 44, and the printing paper 37 that is separated from the drum 26 passes through the conveyance path 45. Then, the paper is discharged onto a paper discharge tray 46 and stacked there.

  During the printing operation, excess ink that has flowed out downstream of the maximum printing area S of the outer peripheral wall 53 flows into the ink recovery port 72. The ink that has flowed into the ink recovery port 72 is recovered in the recovery container 79 by the suction force of the recovery pump 78 of the ink recovery means 73. Further, excess ink that has flowed into the ink collection grooves 71 and 90 is also collected in the collection container 79 via the ink collection port 72 by the suction force of the collection pump 78.

  When printing of the set number of prints is completed, the rotation of the outer peripheral wall 53 of the drum 26 is stopped and the drive of the ink supply means 54 is stopped. Thereby, the supply of the ink 56 to the outer peripheral wall 53 is stopped. The drive of the ink collecting means 73 is stopped a little later than the stop of the ink supply means 54, and excess ink remaining on the outer peripheral wall 53 is collected from the ink collecting port 72. Further, the press roll 35 is returned from the pressing position to the standby position, and the printing operation is completed (step S5). When the printing operation is completed, the timer is initialized and counting is started (step S6), and the standby mode is entered. The timer counts up when the ink remains in the ink supply port 55a, the ink supply path (first pipe 59, etc.), the ink recovery port 72, and the ink recovery path (third pipe 74, etc.). The time is set so as not to dry or solidify. Accordingly, the count-up value (predetermined time from the end of the printing operation) is appropriately determined based on the ink used, the air tightness of the ink supply path, the air tightness of the ink recovery path, and the like.

  If there is a print start request before the timer counts up (step S7), the above-described printing operation is executed (steps S4 and S5). After the printing operation is completed, the timer is initialized again to start counting (step S6), and the standby mode is entered.

  If there is a plate making start request before the timer counts up (step S8), the plate making operation described above is performed, then the first print is performed, and a printing operation or the like is performed according to the request (steps S1 to S5). . After the printing operation is completed, the timer is initialized again to start counting (step S6), and the standby mode is entered.

  Further, if there is a request for starting the plate removal before the timer counts up (step S9), a plate discharging operation is performed (step S10).

  Explaining the plate discharging operation, the base paper clamp portion 27 of the drum 26 is displaced to the clamp release position, and the restriction on the front end side of the stencil base paper 18 is released. Next, the front end side of the stencil sheet 18 that has been unclamped is guided by the stencil conveying unit 47 as the drum 26 rotates, and the stencil sheet 18 is gradually stored in the stencil box 48 by the stencil conveying unit 47. Then, when all the stencil sheets 18 are stored, the process is completed. Here, the timer is not initialized after the end of the plate removal operation. The timer count continues.

  When the timer counts up (that is, when the next printing operation is not executed after the timer starts counting) (step S11), the supply pump 58 of the ink supply means 54 is driven in reverse for a predetermined time with respect to the ink supply time. At the same time, the recovery pump 78 of the ink recovery means 73 is driven to rotate forward for a predetermined time (step S12). When the supply pump 58 is driven in reverse, the residual ink in the ink supply port 55a and the ink supply path is returned to the ink container 57 by suction. Therefore, the residual ink does not dry or solidify in the ink supply port 55a or the ink supply path. Further, when the recovery pump 78 is driven to rotate forward, the residual ink in the ink recovery port 72 and the ink recovery path is returned to the recovery container 79 by suction. Therefore, the residual ink does not dry or solidify in the ink collection port 72 or the ink collection path. From the above, it is possible to prevent problems such as defective printing due to ink drying and ink solidification in the ink supply port 55a and the ink supply path. In addition, problems such as ink leakage due to ink drying and ink solidification in the ink recovery port 72 and the ink recovery path can be prevented.

  In this embodiment, after the printing operation is completed, the plate discharging operation is executed only when there is a plate discharging request from the user, and normally the state in which the stencil sheet 18 is mounted on the drum 26 is maintained. Accordingly, the reverse rotation driving of the supply pump 58 and the normal rotation driving of the recovery pump 78 for returning the residual ink to the ink container 57 and the recovery container 79 are performed with the stencil sheet 18 mounted on the surface of the outer peripheral wall 53. The base paper 18 closes the ink supply port 55a and the ink recovery port 72, and the ink supply path and the ink recovery path are strongly depressurized by driving the supply pump 58 and the recovery pump 78, so that the remaining ink can be effectively used for the ink container 57 and the recovery container. 79.

  In this embodiment, when the next printing is not executed until the predetermined time has elapsed from the end of the printing operation, both the reverse drive of the supply pump 58 and the forward drive of the recovery pump 78 are executed. Only one of them may be executed.

  In the above-described embodiment, the ink collection unit 73 returns the collected ink to the collection container 79. However, the ink collection unit 73 may return the ink to the ink container 57 of the ink supply unit 54.

1 is a schematic configuration diagram of a stencil printing apparatus according to an embodiment of the present invention. It is a perspective view of the drum which showed one Embodiment of this invention and abbreviate | omitted the press means. FIG. 3 shows an embodiment of the present invention and is a cross-sectional view taken along line AA in FIG. 2. FIG. 3 shows an embodiment of the present invention and is a cross-sectional view taken along line BB in FIG. 2. It is the schematic which showed one Embodiment of this invention and expand | deployed the outer peripheral wall of the drum. FIG. 3 is a partial cross-sectional view illustrating an ink diffusion mechanism according to an embodiment of the present invention. 1 is a schematic flowchart of an operation of a stencil printing apparatus according to an embodiment of the present invention.

Explanation of symbols

18 Stencil Paper 26 Drum 27 Base Paper Clamping Section 35 Press Roll 37 Printing Paper (Printing Medium)
53 Outer wall 54 Ink supply means 55a Ink supply port 58 Supply pump 72 Ink recovery port 73 Ink recovery means 78 Recovery pump

Claims (4)

A drum that is rotatable and has an outer peripheral wall formed of an ink impermeable member, a drum on which a stencil sheet is mounted, and an ink supply port on the outer peripheral wall. In a stencil printing apparatus comprising ink supply means for supplying ink to the surface of the outer peripheral wall from a mouth, and a press roll for pressing a fed printing medium against the outer peripheral wall,
A stencil printing apparatus, wherein a supply pump of the ink supply means is driven reversely with respect to the time of ink supply when the next printing is not executed before a predetermined time elapses from the end of the printing operation. A drum that is rotatable and has an outer peripheral wall formed of an ink impermeable member, a drum on which a stencil sheet is mounted, and an ink supply port on the outer peripheral wall. Ink supply means for supplying ink to the surface of the outer peripheral wall from the mouth, a press roll that presses the fed print medium against the outer peripheral wall, and ink that has flowed outside the maximum printing area of the outer peripheral wall is collected. In the stencil printing apparatus provided with an ink collecting means for sucking and collecting from the mouth,
A stencil printing apparatus, wherein a recovery pump of the ink recovery means is driven to rotate forward when the next printing is not executed before a predetermined time elapses from the end of the printing operation. A drum that is rotatable and has an outer peripheral wall formed of an ink impermeable member, a drum on which a stencil sheet is mounted, and an ink supply port on the outer peripheral wall. Ink supply means for supplying ink to the surface of the outer peripheral wall from the mouth, a press roll that presses the fed print medium against the outer peripheral wall, and ink that has flowed outside the maximum printing area of the outer peripheral wall is collected. In the stencil printing apparatus provided with an ink collecting means for sucking and collecting from the mouth,
When the next printing is not executed until the predetermined time has elapsed from the end of the printing operation, the supply pump of the ink supply means is driven in reverse with respect to the time of ink supply, and the recovery pump of the ink collection means is rotated forward. A stencil printing apparatus characterized by being driven. The stencil printing apparatus according to any one of claims 1 to 3,
The stencil printing apparatus, wherein the reverse rotation drive of the supply pump or the forward rotation drive of the recovery pump is performed with the stencil sheet mounted on the surface of the outer peripheral wall.

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