JP2005297194A - Stencil printing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stencil printing apparatus capable of reliably preventing contamination inside the apparatus due to excess ink remaining without being subjected to printing after the printing operation is stopped.
A drum 26 having an outer peripheral wall 53 that is rotatable and formed of an ink impermeable member, on which a stencil sheet is mounted, and an ink supply port 55a on the outer peripheral wall 53. And an ink supply means 54 that supplies ink to the surface of the outer peripheral wall 53 from the ink supply port 55a by the driving force of the supply pump 58, and a press roll 35 that presses the fed printing paper against the outer peripheral wall 53. In the stencil printing machine provided, when the printing operation is stopped, the driving of the supply pump 58 is stopped before the start of printing of the final printed matter and immediately before the ink supply port 55a passes through the press roll 35.
[Selection] Figure 2

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. 23, 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. 24, the ink supply mechanism 105 has an intermediate pressing roll 106 that is an ink supply roll, and the intermediate pressing roll 106 is rotatably provided on a roll support member 107. The intermediate push roll 106 is configured such that the roll support member 107 is urged in the direction of arrow a in FIG. 24 and is 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. 23, 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 method will be briefly described. As shown in FIG. 25, the drum 120 has a drum 120, and a base paper clamping 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. 25, 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 having an ink supply port at a position upstream of the print area and supplying ink to the surface of the outer peripheral wall from the ink supply port by a driving force of a supply pump; and a print medium fed to the outer peripheral wall A stencil printing apparatus provided with a press roll that presses against the stencil has been 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. The diffused ink oozes out from the perforated stencil sheet and is transferred to the printing medium, and the ink image is printed on the printing medium. 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.
JP-A-7-132675 JP 2001-246828 A

  However, in the stencil printing apparatus, if the drive stop timing of the supply pump is not appropriate when the printing operation is stopped, excess ink may remain on the outer peripheral wall. If excess ink remains on the outer peripheral wall, the ink may flow 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 addition, if the driving stop timing of the supply pump is not appropriate when the printing operation is stopped, sufficient ink is not supplied to the final printed material, and an appropriate printed material cannot be obtained.

  Therefore, an object of the present invention is to provide a stencil printing apparatus that can reliably prevent contamination inside the apparatus due to excess ink remaining without being used for printing after the printing operation is stopped. In addition, the present invention provides a stencil printing apparatus capable of reliably preventing contamination inside the apparatus due to excess ink remaining without being subjected to printing after a proper final printed matter is obtained and the printing operation is stopped. The purpose is to provide.

  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. And an ink supply means for supplying ink to the surface of the outer peripheral wall by a driving force of a supply pump from the ink supply port, and presses the fed print medium against the outer peripheral wall. A stencil printing apparatus comprising a press roll, and when the printing operation is stopped, the drive of the supply pump is stopped before the printing of the final printed matter and before the ink supply port passes through the press roll. It is characterized by that.

  In this stencil printing apparatus, ink is not supplied to the outer peripheral wall from the ink supply port after the press roll for printing the final printed matter passes through the ink supply port.

  The invention of claim 2 is the stencil printing apparatus according to claim 1, wherein the drive stop timing of the supply pump when the printing operation is stopped is immediately before the ink supply port passes through the press roll. Features.

  In this stencil printing apparatus, ink is supplied from the ink supply port to the outer peripheral wall until immediately before the press roll for printing the final printed material passes through the ink supply port, so that there is no shortage of ink for the final printed material. At the same time, after the press roll for printing the final printed matter passes through the ink supply port, the ink is not supplied from the ink supply port to the outer peripheral wall.

  The invention of claim 3 is the stencil printing apparatus according to claim 1, wherein the supply pump is configured to be able to rotate forward and reverse, and when the printing operation is stopped, the supply pump is driven in reverse to the ink supply time, It is characterized by being stopped after the reverse drive.

  In this stencil printing apparatus, the ink discharged from the ink supply port can be returned to the ink supply path by the residual pressure in the ink supply path after the supply pump is stopped.

  According to a fourth aspect of the present invention, there is provided the stencil printing apparatus according to the first aspect, wherein an ink recovery port is provided outside the maximum printing area of the outer peripheral wall, and ink recovery means for recovering the ink flowing into the ink recovery port is provided. It is characterized by that.

  In this stencil printing apparatus, ink that has not been used for printing during the printing operation and has flowed out of the maximum printing area can be removed from the outer peripheral wall of the drum.

  According to the invention of claim 1, after the press roll for printing the final printed matter passes through the ink supply port, the ink is not supplied to the outer peripheral wall from the ink supply port. Therefore, after the printing operation is stopped, contamination inside the apparatus due to excess ink remaining without being used for printing can be reliably prevented.

  According to the second aspect of the present invention, ink is supplied to the outer peripheral wall from the ink supply port until immediately before the press roll for printing the final printed material passes through the ink supply port, so that the ink for the final printed material is insufficient. In addition, after the press roll for printing the final printed matter passes through the ink supply port, the ink is not supplied from the ink supply port to the outer peripheral wall. Accordingly, an appropriate final printed matter can be obtained, and contamination inside the apparatus due to excess ink remaining without being subjected to printing after the printing operation is stopped can be reliably prevented.

  According to the invention of claim 3, after the supply pump is stopped, the ink discharged from the ink supply port by the residual pressure in the ink supply path can be returned to the ink supply path. Therefore, it is possible to reliably prevent contamination inside the apparatus due to the ink flowing out due to the residual pressure after the supply pump is stopped.

  According to the fourth aspect of the present invention, it is possible to remove from the outer peripheral wall of the drum the ink that has not been used for printing during the printing operation and has flowed out of the maximum printing area. Therefore, it is not necessary to finely control the amount of ink supplied from the ink supply port based on the print rate of the printed matter. Further, the ink can be reused.

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

  1 to 13 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. FIG. 8 is a sectional view of the drum showing the position where the drum rotation angle is 0 degree, FIG. 9 is a sectional view of the drum showing the position where the drum rotation angle is 185 degrees, and FIG. FIG. 11 is an operation flowchart when driving of the supply pump is stopped, FIG. 12 is a time chart when the set number of prints is completed, and FIG. 13 is a time chart when the stop key is operated during the printing operation.

  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 drum angle reference 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 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 print paper 37 from the drum 26, a paper discharge sensor 93 that detects whether the print paper 37 is discharged from the drum 26, and the paper separation. It has a conveyance path 45 in which the printing paper 37 separated from the drum 26 by the 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 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 supply tank 57 in which the ink 56 is stored, the supply pump 58 that sucks the ink 56 in the supply tank 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 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 55 is provided at a printing upstream position from the maximum printing area and at a printing downstream position from the base paper clamp unit 27. The ink supply unit 55 may be provided at a position on a boundary line that divides the maximum printing area and a non-printing area upstream thereof, and at a printing upstream position within the maximum printing area. When the ink 56 is disposed within 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 a boundary line that divides the maximum printing area and a non-printing area upstream thereof.

  Next, the control system will be briefly described.

  As shown in FIG. 10, the control unit 94 inputs a command signal from the operation panel 95 or inputs sensor outputs of the paper discharge sensor 93, the drum angle reference sensor 30, and the like, and performs a printing operation based on the input signals. The main motor 25, the supply pump 58, and the like are driven via the drive circuit 96 in order to execute the plate making operation, the plate discharging operation, and the like. When the printing operation is stopped, the driving of the supply pump 58 is stopped according to the flow shown in FIG. The details of the control will be described later in the section of action.

  The operation panel 95 is provided with a numeric keypad, a printing / plate making mode selection key, a start key, a stop key, and the like.

  The control unit 94 can detect the rotation angle of the drum 26 based on the sensor output of the drum angle reference sensor 30 and the output of the encoder 97. The rotation angle of the drum 26 is a reference position where the drum position shown in FIG. 8 is 0 degrees. At the rotation position of 145 degrees, the end position of the maximum printing area faces the press roll 35, and at the rotation position of 185 degrees (position in FIG. 9), the position between the base paper clamp portion 27 and the ink supply port 55a is pressed. Opposite to the roll 35, the ink supply port 55a is at a position facing the press roll 35 at a rotation position of 195 degrees.

  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 in the supply tank 57 is guided to the ink supply port 55a, and the ink 56 is supplied to the outer peripheral wall 53 from the ink supply port 55a. 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.

  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 almost completed, the printing operation is stopped. Specifically, the drive of the supply pump 58 of the ink supply means 54 is stopped, the press roll 35 is returned from the pressing position to the standby position, the rotation of the outer peripheral wall 53 of the drum 26 is stopped, and the standby mode is entered. Further, not only when the set number of prints have been completed, but also when the printing is forcibly stopped by a user command (stop key operation) or the like, the standby mode is entered by substantially the same operation.

  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.

  Next, based on the flowchart of FIG. 11 and the time charts of FIGS. 12 and 13, the drive stop operation of the supply pump 58 when the printing operation is stopped will be described. As shown in FIGS. 11 and 12, during the printing operation, when the sheet discharge sensor 93 detects the passage of the printing paper and the number counter for counting the number of printed sheets becomes 1 by the detection signal (step S2). The stop processing signal is set to the H level state. Then, with reference to the output of the next drum angle reference sensor 30, when the drum 26 is rotated at 185 degrees (position in FIG. 9), that is, immediately before the ink supply port 55a passes through the press roll 35 (step S3). The drive of the supply pump 58 is stopped (step 4).

  As shown in FIGS. 11 and 13, when the stop key of the operation panel 95 is operated during the printing operation (step S1), the stop processing signal is set to the H level state. Then, with reference to the output of the next drum angle reference sensor 30, when the drum 26 is rotated at 185 degrees (position in FIG. 9), that is, immediately before the ink supply port 55a passes through the press roll 35 (step S3). The drive of the supply pump 58 is stopped (step 4).

  As described above, in this stencil printing apparatus, since the ink 56 is not supplied from the ink supply port 55a to the outer peripheral wall 53 after the press roll 35 for printing the final printed matter passes through the ink supply port 55a, the printing operation is stopped. The excess ink 56 that is not used for printing does not basically remain on the outer peripheral wall 53. Further, until the press roll 35 for printing the final printed matter passes through the ink supply port 55a, the ink 56 is supplied from the ink supply port 55a to the outer peripheral wall 53, so that the ink 56 for the final printed matter is insufficient. There is no. Accordingly, an appropriate final printed matter can be obtained, and contamination inside the apparatus due to excess ink remaining without being subjected to printing after the printing operation is stopped can be reliably prevented.

  14 and 15 show a modified example of the drive stop operation of the supply pump 58 in the first embodiment, FIG. 14 is an operation flowchart when the supply pump 58 is stopped, and FIG. 15 is a time chart at the end of the set number of prints. It is. In this modification, the supply pump 58 is configured to be able to rotate forward and reverse. For clarity of explanation, the same reference numerals as those in the first embodiment are used for explanation.

  Next, based on the flowchart of FIG. 14 and the time chart of FIG. 15, the driving stop operation of the supply pump 58 when the printing operation is stopped will be described. As shown in FIGS. 14 and 15, during the printing operation, when the paper discharge sensor 93 detects the passage of the printing paper and the number counter for counting the number of printed sheets becomes 1 by the detection signal (step S11). The stop processing signal is set to the H level state. Then, with reference to the output of the next drum angle reference sensor 30, when the drum 26 is rotated at 185 degrees (the position in FIG. 9), that is, immediately before the ink supply port 55a passes through the press roll 35 (step S12). The drive of the supply pump 58 is temporarily stopped (step 13). When the drum 26 passes through the rotation position of 195 degrees (step S14), the supply pump 58 starts to be driven in the reverse direction at the time of ink supply, and is driven for the set time Tr, and then the drive of the supply pump 58 is stopped. (Step S17).

  As shown in FIG. 14, when the stop key of the operation panel 95 is operated during the printing operation (step S10), the stop processing signal is set to the H level state. Then, with reference to the output of the next drum angle reference sensor 30, when the drum 26 is rotated at 185 degrees (the position in FIG. 9), that is, immediately before the ink supply port 55a passes through the press roll 35 (step S12). The drive of the supply pump 58 is temporarily stopped (step 13). When the drum 26 passes through the rotation position of 195 degrees (step S14), the supply pump 58 starts to be driven in the reverse direction at the time of ink supply, and is driven for the set time Tr, and then the drive of the supply pump 58 is stopped. (Step S17).

  As described above, also in this modification, after the press roll 35 for printing the final printed matter passes through the ink supply port 55a, the ink 56 is not supplied to the outer peripheral wall 53 from the ink supply port 55a. Surplus ink 56 that is not used for printing basically does not remain on the outer peripheral wall 53. Further, until the press roll 35 for printing the final printed matter passes through the ink supply port 55a, the ink 56 is supplied from the ink supply port 55a to the outer peripheral wall 53, so that the ink 56 for the final printed matter is insufficient. There is no. Accordingly, an appropriate final printed matter can be obtained, and contamination inside the apparatus due to excess ink remaining without being subjected to printing after the printing operation is stopped can be reliably prevented.

  In addition, in this modification, the supply pump 58 is configured to be able to rotate in the forward and reverse directions. When the printing operation is stopped, the supply pump 58 is driven reversely from the ink supply and stopped after the reverse drive. After the stop, the ink 56 discharged from the ink supply port 55a can be returned to the ink supply path by the residual pressure in the ink supply path. Therefore, contamination inside the apparatus due to the ink 56 flowing out due to the residual pressure after the supply pump is stopped can be reliably prevented.

  16 to 21 show a second embodiment of the present invention, FIG. 16 is a perspective view of the drum, FIG. 17 is a sectional view taken along line A2-A2 in FIG. 16, and FIG. 18 is taken along line B2-B2 in FIG. FIG. 19 is a sectional view of the drum showing the position where the drum rotation angle is 0 degree, FIG. 20 is a circuit block diagram of the main part of the control system, and FIG. 21 is an operation flowchart when driving of the supply pump and the recovery pump is stopped. is there.

  As shown in FIGS. 16 to 18, in the second embodiment, compared with the first embodiment, an ink collecting means 73 for collecting the ink 56 leaking from the maximum printing area of the outer peripheral wall 53 is added. The difference is that it is necessary to control the recovery pump 79 of the ink recovery means 73. Since other configurations are the same, the same components are denoted by the same reference numerals, and detailed description thereof is omitted.

  That is, the ink recovery means 73 includes an ink recovery port 72 formed at a position downstream of the maximum print area S of the outer peripheral wall 53, a third pipe 74 having one end of the ink recovery port 2 opened, and the third pipe 74. A rotary joint 63 to which the other end of the pipe 74 is connected and a communication hole 75 is formed, the rotary joint 63 is rotatably supported, a hole 76a to which the communication hole 75 can be connected, and an ink passage 76b is formed inside. A support shaft 50, a fourth pipe 77 having one end connected to the support shaft 50, a filter 80 interposed in the middle of the fourth pipe 77 and trapping paper dust and the like, and in the middle of the fourth pipe 77. A recovery pump (for example, a trochoid pump) 78 that interposes and 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 are configured. That.

  The ink recovery port 72 is formed using an ink recovery recess 81 and a pipe fixing member 82 disposed inside the ink recovery recess 81. 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.

  The collection pump 78 is driven over almost the entire printing operation, and collects the ink 56 leaking from the maximum printing area of the outer peripheral wall 53 into the supply tank 57.

  Next, the control system will be briefly described.

 As shown in FIG. 20, the control unit 94 inputs a command signal from the operation panel 95 or inputs sensor outputs from the paper discharge sensor 93, the drum angle reference sensor 30, and the like, and performs a printing operation based on the input signals. The main motor 25, the supply pump 58, the recovery pump 78, and the like are driven via the drive circuit 96 in order to execute the plate making operation, the plate discharging operation, and the like. Then, when the printing operation is stopped, the driving of the supply pump 58 and the recovery pump 78 is stopped according to the flow shown in FIG.

  Further, as in the first embodiment, the control unit 94 can detect the rotation angle of the drum 26 based on the sensor output of the drum angle reference sensor 30 and the output of the encoder 97. The rotation angle of the drum 26 is a reference position where the drum position shown in FIG. 19 is 0 degrees.

  Next, the drive stop operation of the supply pump 58 and the recovery pump 78 when the printing operation is stopped will be described based on the flowchart of FIG. During the printing operation, when the paper discharge sensor 93 detects the passage of the printing paper and the number counter for counting the number of printed sheets becomes 1 by the detection signal (step S2), the stop processing signal is set to the H level state. . Then, based on the output of the next drum angle reference sensor 30, when the drum 26 is rotated to 185 degrees, that is, immediately before the ink supply port 55a passes through the press roll 35 (step S3), the supply pump 58 is driven. Is stopped (step 4). After the supply pump 58 is stopped, the recovery pump 78 is stopped after a predetermined time has elapsed (step S5).

  If the stop key on the operation panel 95 is operated during the printing operation (step S1), the stop processing signal is set to the H level state. Then, based on the output of the next drum angle reference sensor 30, when the drum 26 is rotated to 185 degrees, that is, immediately before the ink supply port 55a passes through the press roll 35 (step S3), the supply pump 58 is driven. Is stopped (step 4). After the supply pump 58 is stopped, the recovery pump 78 is stopped after a predetermined time has elapsed (step S5).

  As described above, also in this stencil printing apparatus, as in the first embodiment, an appropriate final printed matter can be obtained, and after the printing operation is stopped, the inside of the apparatus caused by the remaining ink that has not been used for printing can be obtained. Contamination can be reliably prevented.

  In the second embodiment, since the ink collecting means 73 is provided, ink that has not been used for printing during the printing operation and has flowed out of the maximum printing area can be removed from the outer peripheral wall 53 of the drum 26. Therefore, it is not necessary to finely control the amount of ink supplied from the ink supply port 55a based on the printing rate of the printed matter. Further, the ink can be reused.

  FIG. 22 shows a modified example of the drive stop operation of the supply pump / recovery pump in the second embodiment, and is an operation flowchart when the drive of the supply pump and the recovery pump is stopped. In this modification, the supply pump 58 is configured to be able to rotate forward and reverse. For clarity of explanation, the same reference numerals as those in the second embodiment are given.

  Next, the drive stop operation of the supply pump 58 and the recovery pump 78 when the printing operation is stopped will be described based on the flowchart of FIG. During the printing operation, when the paper discharge sensor 93 detects the passage of the printing paper and the number counter that counts the number of printed sheets by the detection signal becomes 1 (step S11), the stop processing signal is set to the H level state. . Then, based on the output of the next drum angle reference sensor 30, when the drum 26 rotates at 185 degrees, that is, immediately before the ink supply port 55 a passes the press roll 35 (step S 12), the supply pump 58 is driven. Is temporarily stopped (step 13). Then, when the drum 26 passes through the rotation position of 195 degrees (step S14), the supply pump 58 starts to be driven in the reverse direction at the time of ink supply, and after being driven for the set time Tr, the drive of the supply pump 58 is stopped. (Step S17). After the supply pump 58 is stopped, the recovery pump 78 is stopped after a predetermined time has elapsed (step S18).

  As shown in FIGS. 14 and 16, when the stop key of the operation panel 95 is operated during the printing operation (step S10), the stop processing signal is set to the H level state. Then, with reference to the output of the next drum angle reference sensor 30, when the drum 26 is rotated at 185 degrees (the position in FIG. 9), that is, immediately before the ink supply port 55a passes through the press roll 35 (step S12). The drive of the supply pump 58 is temporarily stopped (step 13). Then, when the drum 26 passes through the rotation position of 195 degrees (step S14), the supply pump 58 starts to be driven in the reverse direction at the time of ink supply, and after being driven for the set time Tr, the drive of the supply pump 58 is stopped. (Step S17). After the supply pump 58 is stopped, the recovery pump 78 is stopped after a predetermined time has elapsed (step S18).

  As described above, also in this modified example, as in the second embodiment, an appropriate final printed matter can be obtained, and after the printing operation is stopped, contamination inside the apparatus caused by the remaining ink that is not used for printing remains. Can be reliably prevented.

  Further, in this modified example, as in the second embodiment, since the ink collecting means 73 is provided, the ink that has not been used for printing in the course of the printing operation and has flowed out of the maximum printing area is the outer peripheral wall 53 of the drum 26. More can be removed. Therefore, it is not necessary to finely control the amount of ink supplied from the ink supply port 55a based on the printing rate of the printed matter. Further, the ink can be reused.

  Further, in this modified example, the supply pump 58 is configured to be able to rotate forward and backward, and when the printing operation is stopped, the supply pump 58 is driven reversely from the ink supply and stopped after the reverse drive. After the stop, the ink 56 discharged from the ink supply port 55a can be returned to the ink supply path by the residual pressure in the ink supply path. Therefore, contamination inside the apparatus due to the ink 56 flowing out due to the residual pressure after the supply pump is stopped can be reliably prevented.

  In the second embodiment, only the ink recovery port 72 is provided at the downstream position of the maximum printing area of the outer peripheral wall 53, but it is covered with the stencil sheet 18 at a position outside the maximum printing area of the outer peripheral wall 53. An ink collection groove that communicates with the ink collection port 72 may be provided at the position. That is, the ink recovery groove and the ink recovery port 72 are arranged in a square shape so that the entire area of the maximum print area is surrounded. With this configuration, it is possible to reliably prevent ink leakage from the top of the maximum print area and the left and right sides.

  In the first and second embodiments, when the printing operation is stopped, the driving of the supply pump 58 is stopped before the start of printing of the final printed matter and immediately before the ink supply port 55a passes through the press roll 35. The drive of the supply pump 58 may be stopped at a point before the ink supply port 55a immediately before passing through the press roll 35.

  In the first and second embodiments, the ink supply ports 55 a of the ink supply unit 55 are continuously formed along the printing orthogonal direction N, and the ink 56 is substantially evenly distributed in the printing orthogonal direction N of the outer peripheral wall 53. To supply. However, the ink supply unit 55 may be configured to supply the ink 56 almost uniformly in the printing orthogonal direction N of the outer peripheral wall 53, and various configurations are conceivable. For example, the ink supply unit 55 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.

  Further, in claim 1 of the present invention, “before the printing of the final printed matter and before the ink supply port passes through the press roll” means that at least the press roll 35 at the time of final printing is the ink supply port 55a. After passing, any timing may be used as long as the ink is not supplied. That is, if the control is performed so that the ink 56 necessary for the remaining printing is supplied onto the outer peripheral wall 53, the driving of the supply pump 58 may be stopped at that time. For example, if the ink necessary for printing two sheets is supplied to the outer peripheral wall 53 in advance while the number counter is 2, the drive of the supply pump 58 can be stopped in this state.

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 sectional drawing of the drum which shows 1st Embodiment of this invention and shows the position where a drum rotation angle is 0 degree | times. It is sectional drawing of the drum which shows 1st Embodiment of this invention and shows the position where a drum rotation angle is 185 degree | times. 1 is a block diagram of a main part of a control system according to a first embodiment of the present invention. FIG. 4 is a flowchart illustrating an operation when the supply pump is stopped according to the first embodiment of the present invention. 6 is a time chart at the end of the set number of prints according to the first embodiment of this invention. FIG. 6 is a time chart illustrating a first embodiment of the present invention when a stop key is operated during a printing operation. It is an operation | movement flowchart at the time of the drive stop of the supply pump which shows the modification of 1st Embodiment of this invention. 6 is a time chart at the end of the set number of prints, showing a modification of the first embodiment of the present invention. It is a perspective view of a drum, showing a 2nd embodiment of the present invention. FIG. 17 shows a second embodiment of the present invention and is a cross-sectional view taken along line A2-A2 in FIG. FIG. 17 shows a second embodiment of the present invention and is a cross-sectional view taken along line B2-B2 in FIG. It is sectional drawing of the drum which shows 2nd Embodiment of this invention and shows the position where a drum rotation angle is 0 degree | times. FIG. 5 is a block diagram of essential parts of a control system, showing a second embodiment of the present invention. FIG. 7 is a flowchart illustrating an operation when the supply pump and the recovery pump are stopped, showing the second embodiment of the present invention. It is an operation | movement flowchart at the time of the drive stop of the supply pump and the collection | recovery pump which shows the modification of 2nd Embodiment of this invention. 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 55a ink supply port 56 ink 58 supply pump 72 ink recovery port 73 ink recovery means

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 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 by a driving force of a supply pump; and a press roll for pressing a fed printing medium against the outer peripheral wall. ,
The stencil printing apparatus, wherein when the printing operation is stopped, the driving of the supply pump is stopped before the start of printing of the final printed matter and before the ink supply port passes through the press roll. The stencil printing apparatus according to claim 1,
The stencil printing apparatus, wherein the supply pump drive stop timing when the printing operation is stopped is immediately before the ink supply port passes through the press roll. The stencil printing apparatus according to claim 1,
The stencil printing apparatus, wherein the supply pump is configured to be capable of forward and reverse rotation, and when the printing operation is stopped, the supply pump is driven reversely with respect to the ink supply and stopped after the reverse drive. The stencil printing apparatus according to claim 1,
An stencil printing apparatus comprising an ink collection port provided outside a maximum printing area of an outer peripheral wall, and having an ink collection unit for collecting ink flowing into the ink collection port.

Images