JP2005297195A - Stencil printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a stencil printer, the inside of which can be surely prevented from being contaminated with surplus ink ejected to an outer peripheral wall or remaining without being used for printing, after a printing operation is stopped. <P>SOLUTION: This stencil printer is equipped with: a rotatable drum 26 which has the outer peripheral wall 53 formed of an ink-impermeable member, and which makes stencil base paper attached to a surface of the outer peripheral wall 53; an ink supply means 54 whose ink supply port 55a is provided on the outer peripheral wall 53, and which supplies ink from the ink supply port 55a to the surface of the outer peripheral wall 53; and a press roll 35 for pressing fed printing paper against the outer peripheral wall 53. The stencil printer recovers the surplus ink on the surface of the outer peripheral wall 53 by driving a supply pump 58 of the ink supply means 54 in the reverse direction of the supply of the ink, when the printing operation is stopped. <P>COPYRIGHT: (C)2006,JPO&NCIPI

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 a printing method of a conventional stencil printing apparatus, there are an inner press method (for example, see Patent Document 1) and an outer press method (for example, see Patent Document 2).

  The inner press method will be briefly described. As shown in FIG. 15, the drum 100 has a drum 100 and a paper cylinder 101, and the drum 100 and the paper cylinder 101 are rotatable in a state in which a part of their outer peripheral surfaces is substantially close to each other. Is provided. A base paper clamp portion 100a for clamping the tip of the stencil base paper 104 is provided on the outer peripheral surface of the drum 100, and the outer peripheral wall other than the base paper clamp portion 100a is flexible and has an ink-permeable screen 102. Is formed.

  An ink supply mechanism 105 is provided inside the drum 100. As shown in FIG. 16, the ink supply mechanism 105 includes an intermediate push roll 106 that is an ink supply roll, and the intermediate push roll 106 is rotatably provided on a roll support member 107. The intermediate pressing roll 106 has a pressing position where the roll support member 107 is urged in the direction of arrow a in FIG. 16 to be pressed against the inner peripheral surface of the screen 102, and the roll support member 107 is rotated in the direction of arrow b in FIG. Thus, it is configured to be able to change between a standby position separated from the inner peripheral surface of the screen 102. The intermediate pressing roll 106 is set to a pressing position when the printing paper 111 passes, and is set to a standby position otherwise. Further, the intermediate pressing roll 106 has a function of applying a printing pressure from the inner peripheral side of the screen 102.

  The roll support member 107 is supported so as to be rotatable about a support shaft 108, and the roll support member 107 is provided with a doctor roll 109 and a drive rod 110, respectively. The doctor roll 109 has a cylindrical shape, and is fixed to the roll support member 107 at a position close to the intermediate push roll 106. The drive rod 110 is rotatably supported by the roll support member 107, and is disposed in an upper space constituted by the outer peripheral surfaces of the intermediate push roll 106 and the doctor roll 109 on the sides close to each other. Ink 103 is supplied to the upper space from an ink supply unit (not shown).

  Next, the outline operation of printing will be described in order. A stencil sheet 104 on which a perforated image is formed is mounted on the outer peripheral surface of the screen 102. In the printing mode, the drum 100 and the paper cylinder 101 are rotated synchronously in the direction indicated by the arrow in FIG. 15, and the printing paper 111 is fed between the drum 100 and the paper cylinder 101.

  When the printing paper 111 is fed, the intermediate pressing roll 106 presses the screen 102, and the intermediate pressing roll 106 rotates following the drum 100 in this pressed state. The ink 103 that has passed through the gap with the doctor roll 109 adheres to the outer peripheral surface of the intermediate pressing roll 106, and the attached ink 103 is sequentially supplied to the inner surface of the screen 102 by the rotation of the intermediate pressing roll 106.

  When the intermediate pressing roll 106 presses the screen 102, the pressing force causes the screen 102 to bulge to the outer peripheral side, and the screen 102 is brought into pressure contact with the paper cylinder 101. Then, the printing paper 111 conveyed between the drum 100 and the paper cylinder 101 is conveyed between the intermediate pressing roll 106 and the paper cylinder 101 while being pressed against the screen 102 and the stencil sheet 104. The ink 103 on the screen 102 side is transferred to the printing paper 111 side from the perforation of the stencil sheet 104 by this pressure contact force, and an ink image is printed on the printing paper 111.

  Further, the outer press system will be briefly described. As shown in FIG. 17, the drum 120 has a drum 120, and a base paper clamp portion 120a for clamping the tip of the stencil base paper 104 is provided on the outer peripheral surface of the drum 120. The outer peripheral wall 120b other than the base paper clamp portion 120a is formed of a porous ink-permeable member (ink-permeable member).

  An ink supply mechanism 125 is provided inside the drum 120. The ink supply mechanism 125 includes a squeegee roll 126 that is rotatably supported and a doctor roll 127 that is disposed in the vicinity of the squeegee roll 126. The ink supply mechanism 125 is disposed in an outer peripheral space surrounded by the squeegee roll 126 and the doctor roll 127. Ink 128 is stored. As the ink 128 adhering to the outer periphery of the rotating squeegee roll 126 passes through the gap with the doctor roll 127, only the ink 128 having a predetermined thickness is attached to the squeegee roll 126. It is supplied to the inner surface of the outer peripheral wall 120b.

  Further, a press roll 130 is provided at a position facing the squeegee roll 126 and outside the drum 120. The press roll 130 presses the outer peripheral wall 120b of the drum 120 and the outer peripheral wall 120b of the drum 120. It is configured to be able to change between a standby position that is separated from the standby position. The squeegee roll 126 is fixed to a support portion that rotatably supports the outer peripheral wall 120b of the drum 120, and the outer periphery of the squeegee roll 126 is not pressed by the press roll 130. The surface and the inner peripheral surface of the outer peripheral wall 120b of the drum 120 are in a slightly spaced state. When the outer peripheral wall 120b of the drum 120 is pressed by the press roll 130, the outer peripheral wall 120b of the drum 120 is bent, so that the outer peripheral surface of the squeegee roll 126 and the inner peripheral surface of the outer peripheral wall 120b of the drum 120 come into contact with each other. To do.

  Next, the outline operation of printing will be described in order. The stencil sheet 104 on which the perforated image is formed is mounted on the outer peripheral surface of the outer peripheral wall 120b of the drum. In the printing mode, the outer peripheral wall 120 b of the drum 120 is rotated in the direction indicated by the arrow in FIG. 17, and the printing paper 111 is fed between the drum 120 and the press roll 130.

  When the printing paper 111 is fed, the press roll 130 presses the outer peripheral wall 120b of the drum 120, and the outer peripheral wall 120b is displaced to the inner peripheral side. Due to this displacement, the outer peripheral wall 120b is pressed against the squeegee roll 126, and the squeegee roll 126 rotates following the drum 120. The ink 128 that has passed through the gap with the doctor roll 127 adheres to the outer peripheral surface of the squeegee roll 126, and the attached ink 128 is sequentially supplied to the inner surface of the outer peripheral wall 120b by the rotation of the squeegee roll 126.

  When the press roll 130 presses the outer peripheral wall 120 b of the drum 120, the printing paper 111 conveyed between the drum 120 and the press roll 130 is pressed against the stencil sheet 104 between the squeegee roll 126 and the press roll 130. It is conveyed while. By this pressure contact force, the ink 128 on the outer peripheral wall 120 b side is transferred to the printing paper 111 side from the perforation of the stencil sheet 104, and an ink image is printed on the printing paper 111.

  By the way, in the conventional inner press type and outer press type stencil printing apparatuses, ink pools are respectively provided in the outer peripheral space of the intermediate pressing roll 106 and the doctor roll 109 and in the outer peripheral space of the squeegee roll 126 and the doctor roll 127. Then, the ink 103 and 128 in the ink reservoir is supplied to the screen 102 and the outer peripheral wall 120b of the drums 100 and 120 during printing. Therefore, when printing is not performed for a long time, the inks 103 and 128 accumulated in the ink reservoir, the inks 103 and 128 attached to the drums 100 and 120, etc. are left in contact with the atmosphere for a long time. There was a problem that the inks 103 and 128 deteriorated.

  Therefore, the present applicant has a peripheral wall that is rotatable and formed of an ink impermeable member, a drum on which the stencil sheet is mounted on the surface of the peripheral wall, and a maximum of the peripheral wall of the drum. An ink supply port that has an ink supply port at a position upstream from the print area, supplies ink to the surface of the outer peripheral wall from the ink supply port, and a press roll that presses the fed print medium against the outer peripheral wall; A stencil printing machine equipped with was proposed.

  In this stencil printing apparatus, when the outer peripheral wall of the drum is rotated and ink is supplied to the surface of the outer peripheral wall from the ink supply port and the printing medium is fed, the printing medium is pressed by a press roll. The stencil sheet is conveyed while being pressed against the outer peripheral wall of the stencil sheet and the drum, while the ink between the outer peripheral wall of the drum and the stencil sheet is diffused downstream in the printing direction by the pressing force of the press roll, The diffused ink oozes out from the perforated stencil sheet and is transferred to the printing medium side, and the ink image is printed on the printing medium. Therefore, the ink supplied to the drum is substantially sealed between the outer peripheral wall of the drum and the stencil sheet. It is held in space and contact with the atmosphere is suppressed. Therefore, it is possible to prevent the quality of the ink from changing without performing printing for a long time.

Incidentally, 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 the supply pump driving when the printing operation is stopped to stop the ink supply to the drum. It will be.
JP-A-7-132675 JP 2001-246828 A

  However, even after the supply pump is stopped, ink may be ejected from the ink supply port due to the residual pressure in the ink supply path. The excess ink ejected in this way flows down to the lowermost end of the outer peripheral wall with the passage of time, and may drop down below the lowermost end of the outer peripheral wall to contaminate the inside of the apparatus. In particular, when low-viscosity ink is used, ink contamination is likely to occur, and countermeasures are desired.

  In addition, there may be excess ink that has not been used for printing on the outer peripheral wall even after the printing operation is stopped, and there is a risk that the surplus ink may drop below the lowermost end of the outer peripheral wall and stain the inside of the apparatus. is there.

  Therefore, the present invention provides a stencil printing apparatus that can reliably prevent contamination inside the apparatus due to excess ink that is discharged to the outer peripheral wall after printing operation is stopped or left without being used for printing. With the goal.

  The invention according to claim 1, which achieves the above object, comprises a drum having an outer peripheral wall that is rotatable and formed of an ink-impermeable member, and a stencil sheet is mounted on the surface of the outer peripheral wall, and the drum. An ink supply port 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. Further, the stencil printing apparatus is provided with surplus ink collecting means for collecting surplus ink on the surface of the outer peripheral wall of the drum when the printing operation is stopped.

  In this stencil printing apparatus, after the printing operation is stopped, the surplus ink remaining on the outer peripheral wall or remaining without being printed can be collected by the surplus ink collecting means.

  A second aspect of the present invention is the stencil printing apparatus according to the first aspect, wherein the excess ink collecting means sucks and collects the excess ink on the outer peripheral wall from the ink supply port. And

  In this stencil printing apparatus, excess ink ejected from the ink supply port by the residual pressure in the ink supply path after the supply pump is stopped can be effectively collected.

  The invention of claim 3 is the stencil printing apparatus according to claim 2, wherein the surplus ink collecting means is the ink supply means having a supply pump capable of forward and reverse rotation, and when the printing operation is stopped, Excess ink is recovered by driving the supply pump in the reverse direction with respect to ink supply.

  In this stencil printing apparatus, since the ink supply means is used as the surplus ink collecting means, it is not necessary to separately provide a means for collecting surplus ink.

  A fourth aspect of the invention is the stencil printing apparatus according to the first aspect of the invention, wherein an ink recovery port is provided outside the maximum printing area of the outer peripheral wall, and an ink recovery means for recovering the ink flowing into the ink recovery port is provided. The surplus ink collecting means is the ink collecting means, wherein the surplus ink is collected by driving the ink collecting means even after the printing operation is stopped.

  In this stencil printing apparatus, after the printing operation is stopped, excess ink remaining without being printed can be collected by using the ink collecting means.

  According to a fifth aspect of the present invention, in the stencil printing apparatus according to the fourth aspect of the present invention, an ink recovery groove that communicates with the ink recovery port is provided on a surface of the outer peripheral wall and outside a maximum printing area. And

  In this stencil printing apparatus, after the printing operation is stopped, the surplus ink remaining without being subjected to printing can be collected that has flowed into the ink collection groove.

  According to the first aspect of the present invention, after the printing operation is stopped, the surplus ink remaining on the outer peripheral wall or remaining without being printed can be collected by the surplus ink collecting means. Therefore, it is possible to reliably prevent contamination inside the apparatus due to excess ink.

  According to the invention of claim 2, surplus ink ejected from the ink supply port by the residual pressure in the ink supply path after the supply pump is stopped can be effectively collected.

  According to the invention of claim 3, since the ink supply means is used as the surplus ink collecting means, it is not necessary to separately provide a means for collecting surplus ink, which contributes to cost reduction and simplification of the configuration.

  According to the fourth aspect of the present invention, after the printing operation is stopped, the surplus ink remaining without being used for printing can be collected using the ink collecting means. Therefore, the ink recovery means can be effectively used.

  According to the fifth aspect of the present invention, after the printing operation is stopped, it is possible to collect the surplus ink that has not been used for printing and that has flowed into the ink collecting groove. Can be recovered.

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

  1 to 7 show a first 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 A1-A1 in FIG. 4 is a cross-sectional view taken along line B1-B1 in FIG. 2, FIG. 5 is a plan view of the drum showing the ink supply unit, FIG. 6 is a cross-sectional view taken along line C1-C1 in FIG. It is a fragmentary sectional view explaining these.

  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 to be transported, the stepping motor 15 that rotationally drives 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 converted into electrical signals. A contact type image sensor 16 for conversion and a document discharge tray 17 for placing a document discharged from the document setting table 10 are provided. 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 that rotates in the direction of arrow A in FIG. 1 by the driving force of the main motor 25, a base paper clamp unit 27 that is provided on the outer peripheral surface of the drum 26 and clamps the leading end of the stencil base paper 18, and a drum 26 is provided with an ink supply means 54 for supplying ink 56 to the surface of 26.

  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 has a press roll 35 disposed below the drum 26, and 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 trial printing), 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 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. The printing paper (printing medium) 37 fed from the paper feeding unit 4 in synchronism with the rotation of the paper is pressed against the stencil paper 18 wound around the drum 26 by the press roll 35, whereby the stencil paper 18 is applied to the printing paper 37. The ink 56 is transferred from the perforations, and an image is printed.

  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.

  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 does not deform when pressed against the press roll 35 and that does not allow the ink 56 to pass therethrough. Note that, depending on the type of the ink impermeable member, for the purpose of forming the outer peripheral surface of the outer peripheral wall 53 into a cylindrical surface without unevenness, etc., fluororesin processing such as Teflon (registered trademark) processing, nickel plating, nickel chrome Various known surface treatments such as plating, hot dip galvanizing, and anodizing may be performed.

  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 is set to an area capable of A3 size printing. An ink supply unit 55 </ b> A of the ink supply unit 54 is provided at an upstream position in the printing direction M of the outer peripheral wall 53.

  As shown in FIGS. 2 to 6, 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 an ink supply part 55A is opened at the other end of the second pipe 64.

  The supply pump 58 is configured to be able to be driven in a direction (reverse direction) opposite to a drive direction (forward direction) at the time of ink supply. The supply pump 58 is controlled to rotate forward from the start to the stop of the printing operation, to reversely drive for a predetermined time from the stop of the printing operation, and to stop after the reverse driving.

  The ink supply unit 55A includes an ink diffusion groove 65 that diffuses the ink 56 from the second pipe 64 in the printing orthogonal direction N, and a plurality of communication holes that are opened at intervals in the printing orthogonal direction N of the ink diffusion groove 65. 66 and an ink supply port 55a serving as an ink diffusion supply unit that communicates with the plurality of communication holes 66 and opens on the surface of the outer peripheral wall 53.

  As shown in FIGS. 5 and 6, the ink diffusion groove 65, the plurality of communication holes 66, and the ink supply port 55a are formed along the direction perpendicular to the printing direction M of the outer peripheral wall 53 (that is, the printing orthogonal direction N). The ink supply recess 67 and the ink distribution member 68 disposed therein are formed. The ink supply ports 55 a are formed continuously 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.

  Here, the arrangement position of the ink supply unit 55A is a print upstream position from the maximum print area, a position on a boundary line that divides the maximum print area and a non-print area upstream thereof, and a print upstream position in the maximum print area. Either may be sufficient. However, when it is arranged at the upstream printing position from the maximum printing area, it is set at the downstream printing position from the base paper clamping unit 27. Further, when the ink 56 is arranged in the maximum printing area, the ink 56 supplied to the surface of the outer peripheral wall 53 is set at a position where it can diffuse at least to the boundary line that partitions the maximum printing area and the non-printing area upstream thereof. The

  Next, the operation of the stencil printing apparatus having the above configuration will be briefly described.

  First, when the plate making mode is selected, the plate making unit 2 transports the stencil sheet 18 by the rotation of the platen roll 21 and the base paper feed roll 22, and a number of thermal heads 20 are based on the image data read by the document reading unit 1. When the heating element selectively generates heat, the stencil sheet 18 is thermally perforated to make a plate, and a predetermined portion of the stencil sheet 18 is cut with a stencil cutter 24 to make a stencil sheet 18 having a desired size.

  In the printing unit 3, the tip of the stencil sheet 18 made by the plate making unit 2 is clamped by the stencil sheet clamping unit 27 of the drum 26, and in this clamped state, the drum 26 is rotated to place the stencil sheet 18 on the outer peripheral surface of the drum 26. Wrap and plate.

  Next, when the printing mode is selected, the drum 26 is rotationally driven in the printing unit 3 and the driving of the supply pump 58 of the ink supply unit 54 is started. Then, the ink 56 is supplied to the outer peripheral wall 53 from the ink supply port 55a, and the supplied ink 56 is held between the outer peripheral wall 53 and the stencil sheet 18, and the press roll 35 is displaced from the standby position to the pressing position. Is done.

  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, as shown in FIG. 7, 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. While being diffused downstream in the printing direction M, the diffused ink 56 oozes out from the perforation of the stencil sheet 18 and is transferred to the printing paper 37 side. As described above, 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.

  When printing of the set number of prints is completed, the rotation of the outer peripheral wall 53 of the drum 26 is stopped, the press roll 35 is returned from the pressing position to the standby position, and the drive of the supply pump 58 of the ink supply means 54 is stopped. Further, when the drive of the supply pump 58 is stopped, the supply pump 58 is immediately driven in reverse from the time of ink supply for a predetermined time, and then stopped. The standby mode is entered upon completion of the above operation. Further, not only when the set number of prints have been completed, but also when the printing is forcibly stopped by a user command or the like, the supply pump 58 shifts to the reverse rotation drive for a predetermined time after stopping the forward rotation drive. And then stopped.

  When the plate discharging process is started by starting a new plate making or the like, the base paper clamp portion 27 of the drum 26 is displaced to the clamp release position, and the leading end side of the stencil paper 18 that has been released from the clamp is conveyed as the drum 26 rotates. It is guided by the means 47 and is stored in the discharge box 48.

  As described above, in this stencil printing apparatus, when the printing operation is stopped, the supply pump 58 is driven in the reverse direction with respect to the drive direction at the time of ink supply, so that excess ink on the surface of the outer peripheral wall 53 is supplied from the ink supply port 55a to the ink supply means 54. Is recovered by. Therefore, it is possible to reliably prevent contamination inside the apparatus due to excess ink. That is, the ink supply unit 54 supplies the ink 56 to the surface of the outer peripheral wall 53 during the printing operation, but also serves as the surplus ink collecting unit that recovers the surplus ink on the surface of the outer peripheral wall 53 after the printing operation.

  In the first embodiment, the surplus ink is collected by using the ink supply port 55a, so that the surplus ink 56 discharged from the ink supply port 55a is effectively used by the residual pressure in the ink supply path after the supply pump 58 is stopped. Can be recovered.

  In the first embodiment, since the ink supply means 54 is used as the surplus ink collecting means, it is not necessary to separately provide a means for collecting surplus ink, which contributes to cost reduction and simplification of the configuration.

  8 to 10 show a second embodiment of the present invention, FIG. 8 is a perspective view of the drum, FIG. 9 is a sectional view taken along line A2-A2 in FIG. 8, and FIG. 10 is taken along line B2-B2 in FIG. It is sectional drawing which follows.

  As shown in FIGS. 8 to 10, in the second embodiment, compared with the first embodiment, an ink collecting means 73 for collecting the ink 56 leaking from the maximum print area S of the outer peripheral wall 53 is added. ing.

  The ink recovery means 73 includes an ink recovery port 72 formed at a position downstream of the maximum printing area of the outer peripheral wall 53, a third pipe 74 having one end of the ink recovery port 72 opened, and the third pipe 74. The rotary joint 63 is connected to the other end thereof, and a communication hole 75 is formed. The rotary joint 63 is rotatably supported, and the support 76 has an ink passage 76b formed therein. A shaft 50, a fourth pipe 77 having one end connected to the support shaft 50, a filter 80 that traps paper dust and the like is interposed in the middle of the fourth pipe 77, and is interposed in the middle of the fourth pipe 77. A recovery pump (for example, a trochoid pump) 78 that sucks the ink 56 in the fourth pipe 77 and a recovery container 79 to which the other end of the fourth pipe 77 is connected. .

  As shown in FIG. 10, the ink recovery port 72 is formed using an ink recovery recess 81 formed in the outer peripheral wall 53 and a pipe fixing member 82 disposed inside the ink recovery port. It is continuously formed at the downstream position and along the printing orthogonal direction N.

  The collection pump 78 is controlled to start driving simultaneously with the start of the printing operation, and stop driving after a predetermined time without stopping the driving simultaneously with stopping the printing operation.

  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.

  In addition, since the other structure is the same as that of the said 1st Embodiment, the same code | symbol is attached | subjected to the same component and detailed description is abbreviate | omitted.

  Next, the printing operation of the stencil printing apparatus will be briefly described.

  In the printing unit 3, the front end of the stencil sheet 18 made by the plate making unit 2 is clamped by the stencil sheet clamping unit 27 of the drum 26, and in this clamped state, the drum 26 is rotated to place the stencil sheet 18 on the outer peripheral surface of the drum 26. It is assumed that it is wound and engraved.

  When the printing mode is selected, the drum 26 is rotated in the printing unit 3 and the supply pump 58 of the ink supply unit 54 and the recovery pump 78 of the ink recovery unit 73 are started to be driven. Then, ink is supplied to the outer peripheral wall 53 from the ink supply port 55a, and the supplied ink is held between the outer peripheral wall 53 and the stencil sheet 18, and the press roll 35 is displaced from the standby position to the pressing 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 held between the outer peripheral wall 53 of the drum 26 and the stencil sheet 18 diffuses downstream in the printing direction M while being squeezed by the pressing force of the press roll 35. At the same time, the diffused ink oozes out from the perforation of the stencil sheet 18 and is transferred to the printing paper 37 side. As described above, 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 print area of the outer peripheral wall 53 flows into the ink recovery port 72 of the ink recovery means 73 and is recovered, so that ink leakage from the outer peripheral wall 53 is prevented. Is done.

  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 supply pump 58 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 recovery pump 78 of the ink recovery means 73 is stopped slightly later than the stop of the ink supply means 54, and excess ink remaining on the outer peripheral wall 53 is recovered from the ink recovery port 72. Further, the press roll 35 is returned from the pressing position to the standby position. Upon completion of the above operation, the standby mode is entered.

  In the second embodiment, since the ink collecting unit 73 is driven when the printing operation is started, the ink leaked outside the maximum printing area of the outer peripheral wall 53 can be collected during the printing operation, and the printing operation can be performed. It is possible to prevent the inside of the apparatus from being contaminated by excess ink.

  When the printing operation is stopped, the ink supply means 54 is stopped, but the ink collecting means 73 is stopped when a predetermined time has elapsed. Therefore, after the printing operation is stopped, surplus ink remaining without being used for printing is collected by the ink collecting means 73 from the ink collecting port 72. Therefore, it is possible to reliably prevent contamination inside the apparatus due to excess ink. That is, the ink collecting unit 73 also serves as a surplus ink collecting unit that collects the surplus ink 56 on the surface of the outer peripheral wall 53 during the printing operation and collects the surplus ink on the surface of the outer peripheral wall 53 after the printing operation. . Therefore, the ink recovery means 73 can be used effectively.

  Furthermore, if the ink supply means 54 is driven reversely after stopping the printing operation as in the first embodiment, excess ink on the outer peripheral wall 53 can be recovered from both the ink supply port 55a and the ink recovery port 72. That is, the ink supply means 54 and the ink recovery means 73 are used as the surplus ink recovery means. By using both means in this way, contamination inside the apparatus due to excess ink can be more effectively prevented.

  11 to 14 show a third embodiment of the present invention, FIG. 11 is a perspective view of the drum, FIG. 12 is a cross-sectional view taken along line A3-A3 in FIG. 11, and FIG. 13 is taken along line B3-B3 in FIG. FIG. 14 is a schematic developed view of the outer peripheral wall of the drum.

  As shown in FIGS. 11 to 14, in the third embodiment, compared with the second embodiment, ink recovery grooves 71 a and 71 b are added to the outer peripheral wall 53 of the drum 26.

  The ink collection grooves 71a and 71b are positions outside the maximum printing area S (shown in FIG. 14) of the outer peripheral wall 53 of the drum 26 and covered with the stencil sheet 18 and upstream of the maximum printing area S. And at the top position between the ink supply port 55a and the base paper clamp part 27 and the left and right side positions in the printing orthogonal direction N from the maximum printing area S. That is, the ink collection grooves 71a and 71b and the ink collection port 72 are arranged in a square shape so that the entire area of the maximum print area S is surrounded. The ink collecting groove 71a at the top position and the ink collecting grooves 71b at the left and right outer side positions communicate with each other, and the ink collecting grooves 71b at the left and right side positions communicate with the ink collecting port 72.

  In addition, since the other structure is the same as that of the said 2nd Embodiment, the same code | symbol is attached | subjected to the same component and detailed description is abbreviate | omitted.

  In the third embodiment, since the ink collection grooves 71a and 71b communicating with the ink collection port 72 are provided on the surface of the outer peripheral wall 53 and outside the maximum printing area S, after the printing operation is stopped, Of the excess ink remaining without being used for printing, the ink that has flowed into the ink collection grooves 71a and 71b can also be collected, so that the excess ink can be collected more reliably.

  In the third embodiment, the ink collection grooves 71a and 71b are provided at both the top position of the maximum print area S and the left and right outer side positions, but only the left and right outer side positions of the maximum print area S. Alternatively, it may be provided only at the top position.

  In the first to third embodiments, the ink supply unit 55A has the ink supply port 55a continuously opened along the printing orthogonal direction N of the outer peripheral wall 53. When the ink 56 is diffused downstream in the printing direction, the ink 56 is diffused without being biased in the printing orthogonal direction N. Therefore, uneven printing density in the printing orthogonal direction N can be reliably prevented. Here, the ink supply unit 55A may be provided along the printing orthogonal direction N of the outer peripheral wall 53 and may be configured to supply the ink 56 substantially uniformly in the printing orthogonal direction N, and various configurations are conceivable. For example, the ink supply unit 55 </ b> A may include a plurality of ink supply ports that are opened at equal intervals along the printing orthogonal direction N of the outer peripheral wall 53.

1 is a schematic configuration diagram of a stencil printing apparatus according to a first embodiment of the present invention. 1 is a perspective view of a drum according to a first embodiment of the present invention. FIG. 3 shows the first embodiment of the present invention and is a cross-sectional view taken along line A1-A1 in FIG. FIG. 3 shows the first embodiment of the present invention and is a cross-sectional view taken along line B1-B1 in FIG. It is a top view of the drum which shows 1st Embodiment of this invention and shows an ink supply part. FIG. 6 shows the first embodiment of the present invention and is a cross-sectional view taken along line C1-C1 in FIG. It is a fragmentary sectional view showing a 1st embodiment of the present invention and explaining an ink diffusion mechanism. It is a perspective view of a drum, showing a 2nd embodiment of the present invention. FIG. 9 shows a second embodiment of the present invention and is a cross-sectional view taken along line A2-A2 in FIG. FIG. 10 shows a second embodiment of the present invention and is a cross-sectional view taken along line B2-B2 in FIG. It is a perspective view of a drum, showing a 3rd embodiment of the present invention. FIG. 12 shows a third embodiment of the present invention and is a cross-sectional view taken along line A3-A3 in FIG. FIG. 13 shows a third embodiment of the present invention and is a cross-sectional view taken along line B3-B3 in FIG. It is the schematic which showed 3rd Embodiment of this invention and expand | deployed the outer peripheral wall of the drum. It is the schematic of the principal printing part of the inner press system of a prior art example. It is the schematic of the ink supply means of the inner press system of a prior art example. It is the schematic of the printing principal part of the outer press system of a prior art example.

Explanation of symbols

18 Stencil Paper 26 Drum 35 Press Roll 37 Printing Paper (Printing Medium)
53 outer peripheral wall 54 ink supply means (excess ink collecting means)
55a Ink supply port 56 Ink 58 Supply pump 71a, 71b Ink collection groove 72 Ink collection port 73 Ink collection means (surplus ink collection means)

Claims (5)

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 on the surface of the outer peripheral wall, and an ink supply port on the outer peripheral wall of the drum, A stencil printing apparatus comprising 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 printing medium against the outer peripheral wall,
A stencil printing apparatus comprising surplus ink collecting means for collecting surplus ink on a surface of the outer peripheral wall of the drum when a printing operation is stopped. The stencil printing apparatus according to claim 1,
The stencil printing apparatus, wherein the surplus ink collecting means collects surplus ink on the outer peripheral wall by sucking from the ink supply port. The stencil printing apparatus according to claim 2,
The surplus ink collecting means is the ink supplying means having a supply pump capable of rotating forward and reverse, and when the printing operation is stopped, the surplus ink is recovered by driving the supply pump in reverse to the ink supply time. A stencil printing apparatus characterized by being configured as described above. The stencil printing apparatus according to claim 1,
An ink recovery port is provided outside the maximum printing area of the outer peripheral wall, and ink recovery means for recovering ink flowing into the ink recovery port is provided.
The stencil printing apparatus, wherein the surplus ink collecting means is the ink collecting means, and the surplus ink is collected by driving the ink collecting means even after the printing operation is stopped. The stencil printing apparatus according to claim 4,
An stencil printing apparatus comprising an ink collection groove communicating with the ink collection port on a surface of the outer peripheral wall and outside a maximum printing area.

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