Stencil printing device

Abstract

To provide a stencil printing device that can transport original paper properly.SOLUTION: A stencil printing device includes: a plate-making part including a thermal head and a platen roller; an instruction part to which an instruction for plate making is input; and a controller. A guide member for supporting a leading end of original paper from below on a downstream side from the platen roller is provided in the plate-making part. The controller controls the plate-making part, rotates the platen roller in an opposite direction to those during plate making, and inversely transports the original paper by a predetermined distance before the thermal head makes a plate to original paper on the basis of an instruction of plate making from the instruction part.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a stencil printing apparatus. [Background technology]

[0002] Patent Document 1 discloses a stencil printing machine having a platemaking section (plate feeding mechanism) for making a stencil. The platemaking section is provided with a platen roller, a thermal head, and a guide member for supporting the stencil from below downstream of the platen roller in the conveying direction of the stencil. The stencil is conveyed while being pressed against the thermal head by the platen roller, and is made into a plate by the thermal head. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2000-168221 A Summary of the Invention [Problem to be solved by the invention]

[0004] When the platen roller presses the stencil paper against the thermal head while the stencil paper is being transported, static electricity is likely to be generated, causing the stencil paper to become charged, which may cause the leading edge of the stencil paper to stick to the guide member. Also, when the stencil paper after plate making is cut with a cutter and separated from the stencil paper roll, a burr-like thing may be generated at the leading edge of the stencil paper being unwound from the stencil paper roll, and this burr may get caught in the guide member. Thus, if plate making is performed in a state where the leading edge of the stencil paper is stuck or caught in the guide member, there is a risk of problems with the transport of the stencil paper.

[0005] SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to provide a stencil printing machine capable of properly transporting a stencil sheet. [Means for solving the problem]

[0006] The stencil printing device of the present invention is a stencil printing device comprising a platemaking unit having a thermal head for making a plate on the transported base paper and a platen roller for transporting the base paper while pressing it against the thermal head, an instruction unit for inputting platemaking instructions to the platemaking unit, and a control unit for controlling the platemaking unit to execute the platemaking operation, characterized in that the platemaking unit is provided with a guide member for supporting the front end of the base paper from below, downstream of the platen roller in the transport direction of the base paper, and the control unit, based on platemaking instructions from the instruction unit, rotates the platen roller in the opposite direction to that during platemaking before the thermal head makes a plate on the base paper, and transports the base paper backward a predetermined distance.

[0007] In addition to the above configuration, the present invention can further include the following configuration.

[0008] (a) The guide member is characterized in that a flexible guide portion that guides the stencil paper to a printing unit is formed at a downstream end in the transport direction.

[0009] (b) The plate-making unit is characterized in that a leading end sensor for detecting the leading end is provided between the thermal head of the transport path of the base paper and the downstream end of the guide member in the transport direction, and the control unit transports the base paper in the reverse direction until the leading end is no longer detected by the leading end sensor. Effect of the Invention

[0010] In the stencil printing machine of the present invention, before the stencil paper is made into a plate by the thermal head, the platen roller is rotated in the opposite direction to that during the stencil making, and the stencil paper is conveyed backward by a predetermined distance, so that the stencil paper is pulled back a predetermined amount toward the upstream side along the upper surface of the guide member. Therefore, the state in which the front end of the stencil paper is in close contact with the guide member before the stencil paper is made into a plate can be eliminated, and the problem of the stencil paper upstream of the front end of the stencil paper bending in a Z-shape in the conveying direction on the conveying path of the stencil paper, which causes a conveying malfunction, can be solved.

[0011] Furthermore, in a stencil printing device having the above configuration (a), the guide member has a flexible guide section formed at the downstream end in the transport direction for guiding the stencil paper to the printing section. Therefore, when the stencil paper is supplied from the platemaking section to the printing section, if the tension on the stencil paper transported between the platemaking section and the printing section increases, the guide section will bend and deform, preventing excessive tension, and the stencil paper can be supplied without being damaged.

[0012] Furthermore, in a stencil printing device having the above configuration (b), the platemaking unit is provided with a front end sensor that detects the front end between the thermal head of the stencil paper transport path and the downstream end of the guide member in the transport direction, and the control unit reverses the transport of the stencil paper until the front end is no longer detected by the front end sensor.Therefore, even if the front end position of the stencil paper in the transport path temporarily retreats upstream due to the reverse transport of the stencil paper, the front end position of the stencil paper can be confirmed and grasped again when platemaking of the stencil paper begins, and the stencil can be made in the appropriate position of the stencil paper without causing the platemaking position to shift. [Brief description of the drawings]

[0013] [Figure 1] 1 is a schematic diagram of a stencil printing apparatus according to the present invention; [Diagram 2] FIG. 2 is a block diagram of a control system according to the present invention. [Diagram 3] FIG. 4 is a schematic diagram of the plate making unit before the stencil sheet is conveyed backward. [Figure 4] FIG. 4 is a schematic diagram of the plate making unit when the stencil sheet is conveyed in the reverse direction. [Diagram 5] FIG. 2 is a schematic diagram of the plate-making unit in a state where the stencil sheet is transported in the transport direction [Figure 6] 4 is a flowchart relating to a plate-making operation. [Figure 7] 13 is a flowchart showing a plate-making operation in a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] The stencil printing device 1 of the present invention will be described below with reference to the drawings. Note that the following description is essentially merely illustrative and is not intended to limit the present disclosure, its applications, or its uses. Furthermore, the drawings are schematic, and the ratios of each dimension do not necessarily match the actual ones. For convenience of explanation, the upstream side of the conveying direction Y of the paper P is simply called "front". The downstream side of the conveying direction Y of the paper P is simply called "rear". In addition, the downstream side of the conveying direction F of the base paper G is simply called "downstream". The upstream side of the conveying direction F of the base paper G is simply called "upstream".

[0015] [Stencil printing device] Fig. 1 is a schematic diagram showing a stencil printing machine 1 of the present invention, Fig. 2 is a block diagram of a control system of the present invention, Fig. 3 is a schematic diagram of the plate making section before the stencil paper is conveyed backward, Fig. 4 is a schematic diagram of the plate making section after the stencil paper is conveyed backward, and Fig. 5 is a schematic diagram of the plate making section when the stencil paper is conveyed in the conveying direction. In Fig. 1, the stencil printing machine 1 includes a paper feed section 2, a printing section 3, a paper discharge section 4, and a control section 8. As shown in Fig. 1, the stencil printing machine 1 is configured to convey paper P in the conveying direction Y in the paper feed section 2, the printing section 3, and the paper discharge section 4. A paper feed port 12 is formed in the front of the main body 11 of the stencil printing machine 1, and a paper discharge port 13 is formed in the rear.

[0016] The paper feed unit 2 is provided in front of the main body 11. The paper feed unit 2 includes a paper feed tray 21 on which paper P is placed through the paper feed port 12, a paper feed roller 22 and a separating member 23 provided behind the paper feed tray, and a timing roller 24 disposed behind the paper feed roller 22. The paper feed roller 22 and the separating member 23 are configured to feed the paper P placed on the paper feed tray 21 one sheet at a time in the conveying direction Y from the top. The timing roller 24 is configured to send the paper P to the printing unit 3 at a predetermined timing so that the paper P can be printed at a predetermined position.

[0017] The printing unit 3 is provided behind the paper feed unit 2 inside the main body 11. The printing unit 3 includes a plate cylinder 31 for printing an image on paper P, and a press roller 32 disposed below the plate cylinder 31 so as to face the plate cylinder 31. The press roller 32 is configured to press the paper P against the plate cylinder 31. An ink supply unit 311 is provided inside the plate cylinder 31. The ink supply unit 311 is configured to supply ink used for printing to the circumferential surface of the plate cylinder 311. A holding member 312 is provided on a part of the circumferential surface of the plate cylinder 31. The holding member 312 extends in the axial direction of the plate cylinder 31, and is configured to hold the front end Gf of the base paper G.

[0018] The paper discharge section 4 is provided at the rear of the main body 11. The paper discharge section 4 includes a paper discharge unit 41 and a paper discharge tray 42. The paper discharge unit 41 is configured to transport the paper P printed by the printing section 3 rearward and discharge the paper P to the outside of the main body 11 through the paper discharge port 13. The paper discharge tray 42 is provided outside the rear of the main body 11, and is configured to stack the discharged paper P.

[0019] Inside the main body 11, a platemaking unit 5 is provided above the paper feed unit 2. As will be described later, the platemaking unit 5 is configured to make a plate on a stencil paper G paid out from a stencil paper roll 51 and supply the plate to a plate cylinder 31 of the printing unit 3.

[0020] Inside the main body 11, a plate discharge section 6 is provided above the paper discharge unit 41. The plate discharge section 6 includes a recovery unit 61. The recovery unit 61 is configured to peel off the stencil paper G that has been used in printing and is no longer needed from the plate cylinder 31 and recover it.

[0021] Furthermore, on the top of the main body 11, there are provided an operation panel 7 and a scanner unit 9 for reading a document.

[0022] [Control Unit] 2, an operation panel 7 is connected to the control unit 8. The control unit 8 includes, for example, a CPU for performing calculations, a ROM for storing programs or data required for the operation of the stencil printing device 1, a RAM, and an EEPROM which is a non-volatile memory.

[0023] The control unit 8 controls the operation of each unit of the stencil printing machine 1 based on settings and instructions related to printing or stencil making inputted from the operation panel 7.

[0024] The control unit 8 is also connected to the thermal head 52, plate feed motor 531, leading edge sensor 55, and cutter motor 573 of the plate making unit 5, which will be described later. The control unit 8 controls the operations of the thermal head 52, plate feed motor 531, and cutter motor 573 of the plate making unit 5, based on plate making instructions input from the operation panel 7 and the position of the stencil G (leading edge Gf) input from the leading edge sensor 55. In other words, the operation panel 7 functions as an instruction unit that inputs plate making instructions to the control unit 8.

[0025] [Prepress department] The platemaking section 5 is configured so that a base paper roll 51, on which the base paper G is wound in a roll shape, is mounted in a mounting section 511. The platemaking section 5 includes a thermal head 52, a platen roller 53, a guide member 54, and a front end sensor 55. In the platemaking section 5, a transport path 50 for the base paper G is formed by the thermal head 52, the platen roller 53, and the guide member 54.

[0026] The thermal head 52 has a heater unit 521 and is configured to make a plate on the stencil paper G fed from the stencil paper roll 51 by the heater unit 521 .

[0027] The plate making section 5 also includes a plate feed motor 531 that drives the platen roller 53. The platen roller 53 is disposed above and facing the thermal head 52, and is configured to rotate when the drive of the plate feed motor 531 is transmitted by a drive transmission mechanism (not shown). The plate feed motor 531 is configured to be rotatable in both forward and reverse directions. When the plate feed motor 531 is driven to rotate in the forward direction, the platen roller 53 is rotated in the direction of arrow A. When rotated in the direction of arrow A, the platen roller 53 transports the stencil paper G in the transport direction F while pressing it against the heater section 521 of the thermal head 52 from above.

[0028] Conversely, when the plate feed motor 531 is driven to rotate in the reverse direction, the platen roller 53 rotates in the direction of the arrow B. When rotated in the direction of the arrow B, the platen roller 53 transports the base paper G in the direction opposite to the transport direction F (the upstream direction of the transport direction F).

[0029] The guide member 54 is disposed downstream of the platen roller 53 and configured to support the stencil paper G from below. The guide member 54 has a base portion 541 and a non-conductive guide portion 542. The base portion 541 is formed in a rectangular shape in a plan view, extends in a width direction perpendicular to the conveying direction F, and both ends in the width direction are fixed to side plates (not shown) constituting the frame of the plate making unit 5. The non-conductive guide portion 542 is formed in a substantially trapezoidal shape so that the downstream side is wider than the upstream side in a plan view, extends in the width direction by substantially the same length as the width direction length of the base portion 541, and is fixed to the upper surface of a step portion 545 provided at the downstream end of the base portion 541. That is, the guide member 54 has the non-conductive guide portion 542 formed at a downstream end 543 (downstream end in the conveying direction) of the conveying direction F of the stencil paper G. The upper surface of the non-conductive guide portion 542 is adjusted to be at the same height or lower than the upper surface of the base portion 541. The upper surfaces of both the base portion 541 and the non-conductive guide portion 542 form the transport path 50 for the stencil paper G. The shape of the non-conductive guide portion 542 is not limited to the above shape (approximately trapezoidal when viewed from above), and may be formed into a rectangular shape when viewed from above.

[0030] The base part 541 is formed to have rigidity from metal such as aluminum, iron, or stainless steel, or resin such as ABS, polyacetal, acrylic, etc. To reduce static electricity buildup on the base paper G, it is preferable to form the base part 541 from metal, and it is more preferable to form the base part 541 from stainless steel in terms of rust resistance and parts cost.

[0031] The non-conductive guide portion 542 is made of a resin such as polypropylene, polyethylene, or PET. The non-conductive guide portion 542 is also formed to have flexibility. The non-conductive guide portion 542 acts as a guide portion that guides the stencil paper G to the printing unit 3. When the stencil paper G is wound around the plate cylinder 31, the front end Gf of the stencil paper G is held by the holding member 312 of the plate cylinder 31, and the plate cylinder 31 is rotated in the direction of the arrow C shown in FIG. 1. The stencil paper G is pulled out to the printing unit 3 while being bent at an acute angle at the front end of the guide member 54, and is attached to the peripheral surface of the plate cylinder 31. A predetermined amount of tension is applied to the stencil paper G. Since the non-conductive guide portion 542 is made of a resin and has flexibility, the non-conductive guide portion 542 flexibly deforms and bends when the stencil paper G is wound around the plate cylinder 31. Even if the base paper G is formed to a thickness of about 40 to 50 μm and is very thin and soft, the base paper G can be properly mounted on the plate cylinder 31 without wrinkles while being given a predetermined amount of tension (appropriate tension) without being damaged. When the base part 541 and the non-conductive guide part 542 are made of the same material, the base part 541 and the non-conductive guide part 542 can be integrally formed.

[0032] The stencil paper G (including the front end Gf of the stencil paper G) is supported from below by the base part 541 and the non-conductive guide part 542 downstream of the platen roller 53 in the conveying direction F of the stencil paper G. Therefore, when conveyance of the stencil paper G is stopped or when the stencil paper G is being conveyed, the front end Gf of the stencil paper G comes into contact with the base part 541 and the non-conductive guide part 542 from above. As shown in FIG. 3, the front end Gf of the stencil paper G is positioned so as to stop at a position a predetermined distance downstream of the front end sensor 55 in a standby state described later, and the front end of the stencil paper G supported by the guide member 54 at this time is the part held by the holding member 312 when the stencil paper G is attached to the plate cylinder 31.

[0033] The front end sensor 55 is configured to detect the front end Gf of the stencil paper G supported by the guide member 54. The front end sensor 55 is provided downstream of the thermal head 52 in the transport direction F and upstream of the front edge 544 of the non-conductive guide part 542 in the transport direction F. In other words, the front end sensor 55 is provided on the transport path 50 of the stencil paper G, between the thermal head 52 and the downstream end 543 in the transport direction F of the guide member 54 (downstream end in the transport direction).

[0034] The front end sensor 55 is a reflective optical sensor and is disposed above the guide member 54. However, the present invention is not limited to this, and a light-transmitting window may be provided in the guide member 54 so as not to prevent the front end sensor 55 from receiving and emitting light, and the front end sensor 55 may be disposed below the guide member 54 or above and below the guide member 54. When the front end sensor 55 is disposed above and below the guide member 54, a transmissive optical sensor is used for the front end sensor 55. Also, although Figs. 3 to 5 show a case in which the front end sensor 55 is disposed above the center of the non-conductive guide portion 542 in the conveying direction F, the front end sensor 55 may be disposed above or below the base portion 541, or may be disposed between the base portion 541 and the cutter 57, or on the upstream side of the cutter 57 in the conveying direction F. By disposing the front end sensor 55 in the center of the non-conductive guide portion 542 in the transport direction F, the transport distance of the base paper G to the plate cylinder 31 after platemaking begins can be shortened, and the time required for the platemaking operation can be shortened.

[0035] The platemaking section 5 includes a cutter 57 disposed downstream of the thermal head 52. The cutter 57 includes an upper blade 571 and a lower blade 572, and is configured to cut the plate-made stencil paper G to a length that approximately corresponds to the circumferential length of the plate cylinder 31. The platemaking section 5 supplies the plate-made stencil paper G cut by the cutter 57 to the plate cylinder 31 by rotating the plate cylinder 31 in the direction of arrow C while the front end Gf is held by the holding member 312.

[0036] [Operation of stencil printing machine] When the user performs stencil making and printing operations using the stencil printing device 1, if the stencil roll 51 is not mounted in the mounting section 511 of the stencil making section 5, the user must mount the stencil roll 51 in the mounting section 511 to keep the stencil G in a standby state in which it can be made into a stencil. First, the user mounts the stencil roll 51 in the stencil making section 5 and clamps the front end Gf of the stencil G between the thermal head 52 and the platen roller 53. After that, when the user performs a predetermined operation for preparing for stencil making, the plate feed motor 531 is driven to rotate in the forward direction, and the platen roller 53 is rotated in the direction of arrow A. By rotating the platen roller 53 in the direction of arrow A, the stencil G is transported downstream in the transport direction F.

[0037] After the leading end sensor 55 detects the leading end Gf of the stencil paper G being transported, when the stencil paper G is further transported a distance L1, the driving of the plate feed motor 531 is stopped and the rotation of the platen roller 53 is stopped. When the rotation of the platen roller 53 is stopped, the transport of the stencil paper G is stopped. This distance L1 is set to, for example, 3 mm. In other words, the leading end Gf of the stencil paper G is stopped at a position 3 mm downstream from the leading end sensor 55 in the transport direction F. The state in which the transport of the stencil paper G is stopped is a standby state in which the stencil paper G can be made into a plate.

[0038] The transport distance of the stencil paper G by the platen roller 53 is measured by counting the number of drive steps of the plate feed motor 531. For example, when the plate feed motor 531 is driven 10 steps to rotate in the forward direction, the stencil paper G is transported 0.3 mm in the transport direction F. When the plate feed motor 531 is driven 10 steps to rotate in the reverse direction, the stencil paper G is transported 0.3 mm in the direction opposite to the transport direction F (upstream direction of the transport direction F).

[0039] In addition, the unmade base paper G (base paper roll 51) remaining after the platemaking operation is performed is transported until the leading end Gf of the base paper G reaches a position 3 mm downstream in the transport direction F from the leading end sensor 55 so that it automatically goes into standby state without the need for user operation.

[0040] 3, the stencil sheet G is in a standby state. That is, the leading end Gf of the stencil sheet G is stopped at a position 3 mm downstream in the transport direction F from the leading end sensor 55.

[0041] A user operates operation panel 7 to input settings related to printing or plate making. For example, printing / plate making density, printing speed, number of copies, etc. are input. When a plate making instruction is input from operation panel 7 to control unit 8, control unit 8 controls plate making unit 5 to execute the plate making operation and also operates scanner unit 9. An original is read by scanner unit 9, and the original image is input to control unit 8.

[0042] When a plate making operation is to be performed, the front end Gf of the stencil paper G in the standby state shown in FIG. 3 may be in a state where it is difficult to convey the stencil paper G appropriately. For example, the platen roller 53 presses the stencil paper G against the thermal head 52 to convey it, which may cause static electricity to be generated and charge the stencil paper G. If the stencil paper G is strongly charged, the stencil paper G (including the front end Gf) may stick to the guide member 54. In particular, the non-conductive guide portion 542 is made of resin and does not allow the static electricity of the charged stencil paper G to escape, so that the stencil paper G is likely to stick to the guide member 54. Also, for example, when the cutter 57 moves the upper blade 571 arranged above and opposite to the lower blade 572 arranged below the conveying path 50 relative to and slides against the lower blade 572 to cut the stencil paper G, the cut edge of the Japanese paper constituting the stencil paper G is slightly bent downward at the front end Gf of the stencil paper G, generating something like a burr. This slight burr at the front end Gf may get caught in fine scratches on the upper surface of the guide member 54.

[0043] Therefore, in the present invention, in the platemaking operation, the stencil paper G in the standby state shown in Fig. 3 is rotated in the opposite direction to that during platemaking before platemaking, and is transported a predetermined distance in the opposite direction to the transport direction F (the upstream direction of the transport direction F) as shown in Fig. 4. Then, after the stencil paper G has been transported the predetermined distance backward, it is transported in the transport direction F and positioned to its original standby position so that the stencil paper G can be transported appropriately, and then platemaking is started.

[0044] 6 is a flow chart of the stencil-making operation. When a stencil-making instruction is input to the control unit 8 from the instruction unit (operation panel 7), the stencil-making operation starts.

[0045] First, in step S10, the control unit 8 drives the plate feed motor 531 to rotate in the reverse direction in the plate making unit 5, which is in a standby state, to rotate the platen roller 53 in the direction of arrow B. That is, the platen roller 53 is rotated in the opposite direction to that during plate making of the stencil paper G. By rotating the platen roller 53 in the direction of arrow B, the stencil paper G is conveyed backward in the conveying direction F to the upstream side.

[0046] In step S11, the control unit 8 judges whether the leading end sensor 55 has stopped detecting the leading end Gf of the stencil paper G being conveyed backward. If the leading end Gf of the stencil paper G has not reached the leading end sensor 55, the leading end Gf is located downstream of the leading end sensor 55. In this case, step S11 is not satisfied, and the platen roller 53 continues conveying the stencil paper G backward, and the control returns to the judgment of step S11.

[0047] In step S11, when the front end Gf of the stencil paper G being conveyed backward reaches the front end sensor 55 and passes the front end sensor 55 upstream, the front end sensor 55 detects that the stencil paper G is no longer present below the installation position of the front end sensor 55. In this case, step S11 is satisfied, and the process proceeds to step S12.

[0048] In step S12, it is determined whether the stencil paper G has been conveyed backward a predetermined distance. Since the backward conveyance of the stencil paper G continues, the front end Gf of the stencil paper G is conveyed backward on the upstream side of the front end sensor 55. The predetermined distance for conveying the stencil paper G backward is the distance for conveying the stencil paper G backward from when the front end sensor 55 no longer detects the front end Gf of the stencil paper G, and corresponds to the distance L2 shown in FIG. 4. This distance L2 is set to, for example, 2 mm. In this case, the distance from the front end sensor 55 as a reference until the front end Gf of the stencil paper G reaches a position 2 mm upstream of the front end sensor 55 in the conveying direction F is the predetermined distance for conveying the stencil paper G backward. In other words, the front end Gf of the stencil paper G conveyed backward by the predetermined distance is returned to a position 2 mm upstream of the front end sensor 55 in the conveying direction F. Conveying the stencil paper G backward by 2 mm corresponds to counting 67 driving steps in the plate feed motor 531 rotated in the reverse direction.

[0049] In step S12, the platen roller 53 continues to transport the stencil sheet G in the reverse direction until the leading end Gf of the stencil sheet G is transported in the reverse direction from the leading end sensor 55 to the upstream side by a distance L2, and the process returns to the determination in step S12.

[0050] In step S12, when the leading edge Gf of the stencil sheet G is transported backward by the distance L2 toward the upstream side from the leading edge sensor 55, step S12 is satisfied, and the process proceeds to step S13.

[0051] The predetermined distance for conveying the stencil paper G in the reverse direction is not limited to the distance set based on the front end sensor 55 as described above. For example, the predetermined distance for conveying the stencil paper G in the reverse direction may be set to a distance obtained by adding the distance L2 to the distance L1 (L1+L2=5 mm) based on the front end Gf of the stencil paper G in the standby state shown in FIG.

[0052] In this case, the distance that the stencil paper G has been conveyed backward is measured at the same time that the platen roller 53 starts to rotate in the direction of arrow B in step S10. The predetermined distance that the stencil paper G has been conveyed backward can be measured by counting the number of drive steps of the plate supply motor 531, as described above. Conveying the stencil paper G backward by 5 mm corresponds to counting 167 drive steps of the plate supply motor 531 that is rotated in the reverse direction. In other words, step S12 is satisfied when the number of drive steps of the plate supply motor 531 counts 167 steps after the platen roller 53 starts to rotate in the direction of arrow B in step S10.

[0053] In either case described above, when the base paper G is transported backward a predetermined distance based on the leading end sensor 55 as a reference, or when the base paper G is transported backward a predetermined distance based on the leading end Gf of the base paper G in a waiting state as a reference, in steps S10 to S12, the control unit 8 transports the base paper G backward until the leading end Gf is no longer detected by the leading end sensor 55.

[0054] Even if the front end Gf of the stencil paper G is stuck or caught on the guide member 54, the front end Gf can be forcibly moved upstream in the conveying direction F by conveying the stencil paper G backward a predetermined distance in steps S10 to S12. That is, the front end Gf of the stencil paper G can be peeled off from the place where it is stuck or caught on the guide member 54. In particular, since the non-conductive guide portion 542 is made of resin, the stencil paper G is likely to stick to the non-conductive guide portion 542. However, even if the front end Gf is stuck to the non-conductive guide portion 542, the front end Gf can be peeled off once by conveying the stencil paper G backward a predetermined distance. Therefore, the state in which the front end Gf of the stencil paper G is not conveyed before the stencil paper G is made into a plate can be easily resolved, and conveying problems can be prevented. Furthermore, if the base portion 541 of the guide member 54 is made of metal, when the stencil paper G is conveyed in the reverse direction, the static electricity that is charged to the stencil paper G at the portion of the stencil paper G that is in contact with the guide member 54 can be removed through the guide member 54. In this case, the charge on the stencil paper G is reduced, and it is possible to prevent the front end Gf of the stencil paper G from sticking to the guide member 54 again.

[0055] When the stencil paper G is transported backward a predetermined distance (step S12 is satisfied), the process proceeds to step S13. In step S13, the control unit 8 drives the plate feed motor 531 to rotate in the forward direction, and rotates the platen roller 53 in the direction of arrow A. By rotating the platen roller 53 in the direction of arrow A, the stencil paper G is transported in the transport direction F.

[0056] In step S14, the control unit 8 judges whether the leading end sensor 55 has detected the leading end Gf of the stencil paper G transported in the transport direction F. If the leading end Gf of the stencil paper G has not reached the leading end sensor 55, the leading end Gf is located upstream of the leading end sensor 55. In this case, step S14 is not satisfied, and the control unit 8 returns to the judgment in step S14 while continuing the transport of the stencil paper G by the platen roller 53.

[0057] In step S14, when the leading end Gf of the stencil sheet G transported in the transport direction F reaches the leading end sensor 55, the leading end sensor 55 detects the leading end Gf. In this case, step S14 is satisfied, and the process proceeds to step S15.

[0058] In step S15, it is determined whether the stencil paper G has been transported a predetermined distance in the transport direction F. During the determination in step S15, the transport of the stencil paper G continues, so the front end Gf of the stencil paper G is located downstream of the front end sensor 55. The predetermined distance by which the stencil paper G is transported in the transport direction F after the front end sensor 55 detects the front end Gf in steps S14 to S15 is the distance by which the stencil paper G is transported in the transport direction after the front end sensor 55 detects the front end Gf of the stencil paper G, and corresponds to the distance L3 shown in FIG. 5. This distance L3 is set to, for example, 3 mm, similar to the distance L1 for positioning the front end Gf of the stencil paper G at the standby position. Using the front end sensor 55 as a reference, the distance until the front end Gf of the stencil paper G reaches a position 3 mm downstream of the front end sensor 55 in the transport direction F is the predetermined distance by which the stencil paper G is transported in the transport direction F. That is, the front end Gf of the stencil paper G transported a predetermined distance in the transport direction F advances to a position 3 mm downstream from the front end sensor 55 in the transport direction F. Transporting the stencil paper G 3 mm in the transport direction F corresponds to counting 100 drive steps in the plate feed motor 531 rotated in the forward direction.

[0059] In step S15, the conveyance of the stencil sheet G by the platen roller 53 continues until the leading end Gf of the stencil sheet G is conveyed downstream from the leading end sensor 55 by a distance L3, and the process returns to the judgment in step S15.

[0060] In step S15, when the leading edge Gf of the stencil sheet G is transported downstream from the leading edge sensor 55 by the distance L3, step S15 is satisfied, and the process proceeds to step S16.

[0061] In steps S10 to S12, the control unit 8 reverses the stencil paper G until the leading end Gf is no longer detected by the leading end sensor 55, so that in steps S13 to S15, when the stencil paper G is transported in the transport direction F, the leading end Gf of the stencil paper G can be detected again.

[0062] When the stencil paper G has been transported a predetermined distance in the transport direction F, in step S16, the control unit 8 heats the heater section 521 of the thermal head 52 based on the original image to make a plate on the stencil paper G. The stencil paper G is transported in the transport direction F while in contact with the heater section 521 of the thermal head 52. A plurality of perforations corresponding to the original image are formed in the stencil paper G by the heated heater section 521. When the stencil paper G has been made into a plate, the execution of the platemaking operation is terminated.

[0063] When the platemaking operation is completed, the control unit 8 drives the cutter motor 573 to operate the cutter 57. By operating the cutter 57, the plate-made stencil paper G is cut to a length that approximately corresponds to the circumferential length of the plate cylinder 31. The plate-made stencil paper G cut by the cutter 57 is supplied to the plate cylinder 31.

[0064] When transporting the base paper G in the transport direction F, the control unit 8 detects the leading end Gf of the base paper G in the above-mentioned step S14. Therefore, based on the detection of the leading end Gf in step S14, the position of the base paper G (leading end Gf) on the transport path 50 can be grasped, and the positional deviation that occurs during plate making in step S16 can be minimized.

[0065] A stencil paper G that has been used in a previous printing and is no longer needed may be wound around the circumferential surface of the plate cylinder 31. As the stencil paper G to be used in a new printing cannot be wound around the plate cylinder 31 in this state, this no longer needed stencil paper G must be peeled off from the plate cylinder 31. The recovery unit 61 peels off the front end Gf of the no longer needed stencil paper G from the holding member 312 of the plate cylinder 31, and pulls the stencil paper G into the recovery unit 61 for recovery.

[0066] A leading end Gf of the stencil paper G supplied from the plate making section 5 is held by a holding member 312 of the plate cylinder 31. As shown in FIG. 1, the plate cylinder 31 is rotated in the direction of arrow C, and the stencil paper G that has been made into a plate is wound around the circumferential surface of the plate cylinder 31.

[0067] When the base paper G is wound around the plate cylinder 31, the paper feed roller 22 rotates at a predetermined timing. When the paper feed roller 22 rotates, only the topmost paper P among the papers P stacked on the paper feed tray 21 is sent to the printing unit 3 by the action of the separating member 23.

[0068] In the printing section 3, ink is supplied by an ink supply unit 311 to the base paper G wound around the circumferential surface of a plate cylinder 31. The paper P sent to the printing section 3 is pressed by a press roller 32 against the plate cylinder 31, which rotates in the direction of arrow C. An image is printed on the paper P by ink that passes through a plurality of perforations formed in the base paper G that correspond to the original image. The paper P is conveyed in the conveying direction Y while being clamped between the plate cylinder 31 and the press roller 32 and printed.

[0069] The printed paper P is transported in the transport direction Y by the paper discharge unit 41 and discharged through the paper discharge port 13. The discharged paper P is stacked on the paper discharge tray .

[0070] (Variation 1) A modified example of the above embodiment will be described below. Fig. 7 shows a flow chart of the plate-making operation in this modified example. Note that steps S20 to S25 and S27 shown in Fig. 7 correspond to steps S10 to S16 shown in Fig. 6, and the description of steps having the same contents will be omitted.

[0071] When a master making instruction is input to the control unit 8 from the instruction unit (operation panel 7), the master making operation is started, and steps S20 to S25 are executed in the same manner as in the above embodiment.

[0072] If the condition in step S25 is met, the process proceeds to step S26.

[0073] In step S26, it is determined whether the reverse transport of the stencil paper G has been performed N times. In this modified example, when step S22 is satisfied and the process proceeds to step S23, the control unit 8 counts internally the number of times N that the stencil paper G has been reverse transported, assuming that the reverse transport of the stencil paper G has been performed once. This number N is set to, for example, three times. The number of times N that the stencil paper G has been reverse transported may be changed to any number by the user operating the operation panel 7.

[0074] In step S26, the process returns to step S20 until the number of times N that the control unit 8 has internally counted that the stencil paper G has been conveyed backward becomes N = 3. That is, the process of conveying the stencil paper G backward and conveying it in the conveying direction F is repeated three times.

[0075] In step S26, when the number of times N that the stencil sheet G has been conveyed backward becomes N=3, step S26 is satisfied, and the process proceeds to step S27.

[0076] In step S27, as in the above embodiment, stencil making is performed on the stencil paper G. When stencil making on the stencil paper G is completed, the execution of the stencil making operation is terminated.

[0077] In this modified example, when the number of times N that the stencil paper is conveyed backward is set to 2 or more, the process of conveying the stencil paper G backward and the process of conveying it in the conveying direction F are repeated multiple times, so that even if the leading end Gf is peeled off from the guide member 54 by conveying the stencil paper G backward once and the leading end Gf is again stuck to or caught on the guide member 54, the operation of peeling off the leading end Gf from the guide member 54 can be repeated by conveying the stencil paper G backward from the second time onwards. By repeating the retreat and advancement of the leading end Gf in this way, the charged state is gradually eliminated and the stencil paper G itself changes to a state in which it is partly raised slightly above the conveying path 50, so that the state in which it is difficult to convey the leading end Gf of the stencil paper G before the stencil paper G is made into a plate can be more reliably eliminated.

[0078] (Variation 2) Another modified example of the above embodiment will be described below. In the above embodiment, the standby state is configured so that the leading end Gf of the stencil paper G is located downstream of the leading end sensor 55 before the start of the platemaking operation, but the standby state may be configured so that the leading end Gf is located upstream of the leading end sensor 55. In other words, when the stencil paper G before platemaking is transported backward a predetermined distance in the direction opposite to the transport direction F (the upstream direction of the transport direction F), the detection of the leading end Gf by the leading end sensor 55 is omitted.

[0079] In this case, the step of determining whether the leading end sensor 55 has stopped detecting the leading end Gf of the stencil sheet G being conveyed backward (step S11 in FIG. 6 and step S21 in FIG. 7) is omitted.

[0080] When a master making command is input, the plate feed motor 531 rotates in the reverse direction, and the platen roller 53 rotates in the direction of arrow B (corresponding to step S10 in FIG. 6 and step S20 in FIG. 7). At the same time that the platen roller 53 starts to rotate in the direction of arrow B, the distance the stencil paper G has been conveyed in the reverse direction is measured, and it is determined whether the stencil paper G has been conveyed in the reverse direction by a predetermined distance (corresponding to step S12 in FIG. 6 and step S22 in FIG. 7). The predetermined distance of reverse conveyance can be measured by counting the number of drive steps of the plate feed motor 531, as in the above embodiment. From a state in which the front end Gf is waiting at a position upstream of the front end sensor 55, the stencil paper G is conveyed in the reverse direction, for example, by 5 mm. Conveying the stencil paper G in the reverse direction by 5 mm corresponds to counting 167 drive steps in the plate feed motor 531 rotated in the reverse direction. That is, when the number of driving steps of the plate feed motor 531 reaches 167 steps after the platen roller 53 starts to rotate in the direction of the arrow B, it is determined that the stencil paper G has been conveyed backward a predetermined distance. After the stencil paper G has been conveyed backward a predetermined distance, steps similar to steps S13 to S16 in Fig. 6 or steps S23 to S27 in Fig. 7 are executed.

[0081] In this modified example as well, the stencil paper G is transported backward a predetermined distance before being made into a plate, so that even if the leading end Gf of the stencil paper G sticks to or gets caught on the guide member 54, the leading end Gf of the stencil paper G can be once peeled off from the guide member 54. This makes it possible to easily resolve the state in which the leading end Gf of the stencil paper G is not transported appropriately before being made into a plate, and to prevent transport problems.

[0082] To summarize the above, the following can be said:

[0083] The stencil printing device 1 of this embodiment is a stencil printing device 1 equipped with a platemaking unit 5 having a thermal head 52 that makes a plate on the transported base paper G and a platen roller 53 that transports the base paper G while pressing it against the thermal head 52, an instruction unit (operation panel 7) that inputs platemaking instructions for the platemaking unit 5, and a control unit 8 that controls the platemaking unit 5 to perform the platemaking operation, and is characterized in that the platemaking unit 5 is provided with a guide member 54 that supports the front end Gf of the base paper G from below, downstream of the platen roller 53 in the transport direction F of the base paper G, and the control unit 8 rotates the platen roller 53 in the opposite direction to that during platemaking (in the direction of arrow B) based on platemaking instructions from the instruction unit (operation panel 7) before the thermal head 52 makes a plate on the base paper G, and transports the base paper G backward a predetermined distance.

[0084] According to the above configuration, the stencil printing device 1 rotates the platen roller 53 in the opposite direction (arrow B direction) to that during stencil making to transport the stencil paper G backward a predetermined distance before the thermal head 52 makes a stencil paper G, so that even if the front end Gf of the stencil paper G is stuck to or caught on the guide member 54, the front end Gf of the stencil paper G can be once peeled off from the guide member 54 by transporting the stencil paper G backward. Therefore, it is possible to easily resolve the state in which the front end Gf of the stencil paper G is not properly transported before the stencil paper G is made into a stencil paper G, and to prevent transport problems.

[0085] Furthermore, in the stencil printing apparatus 1 of this embodiment, the guide member 54 is characterized in that a flexible guide portion (non-conductive guide portion 542) that guides the base paper G to the printing section 3 is formed at the downstream end portion 543 in the conveying direction F.

[0086] According to the above configuration, the guide member 54 has a flexible guide portion (non-conductive guide portion 542) formed at the downstream end portion 543 in the conveying direction F that guides the stencil paper G to the printing section 3. Therefore, even if the front end Gf of the stencil paper G sticks to the non-conductive guide portion 542, the adhesion can be eliminated by reverse conveyance, and when the stencil paper G is attached to the plate cylinder 31, the non-conductive guide portion 542 allows the stencil paper G to be properly wound without being damaged.

[0087] In addition, in the stencil printing device 1 of this embodiment, the plate making unit 5 is characterized in that a front end sensor 55 for detecting the front end Gf is provided between the thermal head 52 of the transport path 50 of the base paper G and the downstream end 543 of the guide member 54 in the transport direction F, and the control unit 8 transports the base paper G in the reverse direction until the front end Gf is no longer detected by the front end sensor 55.

[0088] According to the above configuration, the platemaking section 5 is provided with a leading edge sensor 55 for detecting the leading edge Gf between the thermal head 52 of the transport path 50 of the stencil paper G and the downstream end 543 of the guide member 54 in the transport direction F, and the control section 8 reverses the transport of the stencil paper G until the leading edge Gf is no longer detected by the leading edge sensor 55, so that the leading edge Gf of the stencil paper G can be detected again when the stencil paper G is transported in the transport direction F to make a plate on the stencil paper G. Therefore, a plate can be made on the stencil paper without misalignment of the platemaking position.

[0089] The present invention is not limited to the above-described embodiment and modified examples, and various modifications are possible without departing from the spirit of the invention. [Explanation of symbols]

[0090] 1 Stencil printing device 2 Paper feed section 3 Printing Department 4 Paper ejection section 5 Plate making department 6 Discharge section 7 Operation panel (instruction section) 8. Control Unit 9 Scanner section 11 Main unit 21 Paper feed stand 31 Print cylinder 41 Paper ejection unit 42 Paper receiving tray 50 Transport Path 51 Base paper roll 52 Thermal head 53 Platen roller 54 Guide member 55 Front end sensor 57 Cutter 61 Recovery Unit 541 Base 542 Non-conductive guide part (guide part) G Base paper

Claims

1. a plate making section including a thermal head for making a plate on the conveyed stencil paper and a platen roller for conveying the stencil paper while pressing it against the thermal head; an instruction unit for inputting instructions for plate making of the plate making unit; a control unit that controls the plate making unit to perform the plate making operation; A stencil printing machine comprising: a guide member that supports a leading end of the stencil paper from below, downstream of the platen roller in a transport direction of the stencil paper, The control unit is a platen roller that rotates in a direction opposite to that for platemaking and transports the base paper backward a predetermined distance before the thermal head makes a plate on the base paper based on a platemaking instruction from the instruction unit.

2. 2. The stencil printing apparatus according to claim 1, wherein said guide member is formed with a flexible guide portion at a downstream end in said transport direction for guiding said stencil paper to a printing portion.

3. the plate making unit is provided with a front end sensor for detecting the front end of the stencil sheet between the thermal head and a downstream end of the guide member in the transport direction of the stencil sheet, The control unit is 3. The stencil printing machine according to claim 1, wherein the stencil paper is transported in the reverse direction until the leading end is no longer detected by the leading end sensor.

Images