JP2010253814A - Clamping device and printing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a clamping device and a printing device which enable detection of the presence or absence of a planar member such as a print paper. <P>SOLUTION: The clamping device 33 of the double-sided stencil printing device 1 includes: clamp craws 44 which clamp a printing paper 99; and detection electrodes 45, 46 which are connected to the clamp craws 44, 44. The detection electrodes 45, 46 detect and output electrical changes between the clamps 44, 44. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a clamping device that clamps a planar member such as printing paper, and a printing apparatus including the same.

  2. Description of the Related Art Conventionally, for example, a printing apparatus including a moving guide including a clamping device that clamps printing paper is known.

  Patent Document 1 is passed from a plate cylinder around which stencil paper is wound, a press roller that presses printing paper against a drum, a clamping device that temporarily clamps printing paper printed on one side, and a clamping device. There has been disclosed a stencil printing apparatus capable of double-sided printing provided with a refeed roller for returning the printed paper to the plate cylinder. Here, the re-feed roller is disposed on the side opposite to the plate cylinder with the press roll interposed therebetween.

  In the stencil printing apparatus of Patent Document 1, when the printing paper is conveyed, the printing paper is pressed against the printing drum by a press roller, and an image is printed by the stencil paper wound around the printing drum. Next, the leading edge of the printing paper printed on one side is clamped by the clamping means. Thereafter, when the trailing edge of the printing paper comes out of the pressing portion between the plate cylinder and the press roll, the clamping means then inserts the trailing edge between the refeed roller and the press roller. Next, the printing paper is conveyed around the press roller by the press roller and the refeed roller. Then, the printing paper is conveyed again between the plate cylinder and the press roller, and the back surface is printed.

  Japanese Patent Application No. 2008-152691 discloses a first printing unit that prints an image on one side (front side) of a printing paper, a storage unit that has a clamp device, and an image on the other side (back side) of the printing paper. And a second printing unit that prints the image.

  In the printing apparatus described in Japanese Patent Application No. 2008-152691, when an image is printed on the surface by the first printing unit, the image is conveyed to a storage unit. The printing paper conveyed to the storage unit is conveyed while being clamped by the clamping device of the storage unit and reversed. Thereafter, the printing paper is conveyed to the second printing unit and the back side is printed.

JP 2005-125716 A

  However, the devices disclosed in Japanese Patent Application Laid-Open No. 2008-152691 and Japanese Patent Application No. 2008-152691 have a problem that the presence or absence of printing paper cannot be detected. In view of this, the present inventor has eagerly developed that a reflective sensor is arranged in the vicinity of the clamping device described in Japanese Patent Application No. 2008-152691 (for example, in the vicinity of a pulley 36 in FIG. 2 described later) to detect printing paper. . This makes it possible to detect the presence or absence of printing paper. However, when the reflective sensor is disposed at the above-described location, the printing paper is temporarily clamped between the clamp members, but even if the printing paper is not clamped by other clamping members, The mold sensor determines that there is a clamped print sheet. For this reason, even when the printing paper is not clamped by the clamping device, the printing process is continued, so that printing is performed even though the printing paper is not clamped and conveyed. Further, when the next printing paper is transported in this state, the printing paper remaining without being transported in the vicinity of the clamping device becomes an obstacle, causing problems such as clogging of the printing paper.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a clamping device and a printing device that can detect the presence or absence of a planar member such as a printing paper.

  In order to achieve the above object, the invention described in claim 1 is a first clamp member, a second clamp member that clamps a planar member with the first clamp member, the first clamp member, and the second clamp member. First detection means and second detection means connected to the clamp member, wherein the first detection means and the second detection means detect and output an electrical change between the first clamp member and the second clamp member. A second detection means.

  According to a second aspect of the present invention, the planar member is printing paper, and a first printing unit that prints an image on one side of the printing paper and an image on the other side of the printing paper. The printing paper having the second printing unit for printing and the clamping device according to claim 1, disposed between the first printing unit and the second printing unit, and printed by the first printing unit. And a storage part that conveys the ink to the second printing part.

  According to a third aspect of the present invention, the first clamp member has a first electrode on a side surface facing the second clamp member, and the second clamp member is connected to the first clamp member. A second electrode provided on a side surface on the opposite side, wherein the second electrode is in contact with the first electrode when printing paper is not clamped, and the first detection means includes the first electrode; A first elastic part connected to the second electrode, the second detection means has a second elastic part connected to the second electrode, and the first clamp member and the second clamp member are The first detection unit and the second detection unit are fixed. The first detection unit and the second detection unit are fixed.

  According to a fourth aspect of the present invention, the first detection means and the second detection means are arranged on the upstream side of the clamp region.

  The invention according to claim 5 includes third detection means and fourth detection means for detecting and outputting an electrical change between the first clamp member and the second clamp member, The third detection means has a first elastic part connected to the first electrode, and the fourth detection means has a second elastic part connected to the second electrode, and the third detection means And the fourth detection means is fixed to the downstream side of the clamp region with respect to the first detection means and the second detection means.

  According to the present invention, since the electrical change between the first and second clamp members can be detected and output by the pair of detection means, it is possible to detect the presence or absence of a planar member such as a printing paper.

1 is an overall configuration diagram of a stencil printing apparatus according to a first embodiment. It is a storage part and an enlarged view of the vicinity. It is an enlarged view of a clamp apparatus. It is a perspective view of a detection electrode. It is a front view of the upper part vicinity of the clamp nail which clamped printing paper. It is a front view of the upper part vicinity of the clamp nail which has not clamped printing paper. It is a block diagram explaining the control system of a stencil printing apparatus. It is a flowchart for demonstrating printing operation. It is a figure explaining conveyance of the printing paper by a clamp device. It is a figure explaining conveyance of the printing paper by a clamp device. It is a figure explaining conveyance of the printing paper by a clamp device. It is a figure explaining the clamp nail | claw and detection electrode by 2nd Embodiment.

(First embodiment)
Hereinafter, a first embodiment in which the present invention is applied to a double-sided stencil printing apparatus will be described with reference to the drawings.

  FIG. 1 is an overall configuration diagram of a stencil printing apparatus according to the first embodiment. FIG. 2 is an enlarged view of the reservoir and the vicinity. FIG. 3 is an enlarged view of the clamping device. FIG. 4 is a perspective view of the detection electrode. FIG. 5 is a front view of the vicinity of the upper portion of the clamping claw that clamps the printing paper. FIG. 6 is a front view of the vicinity of the upper portion of the clamping claw that does not clamp the printing paper. FIG. 7 is a block diagram illustrating a control system of the stencil printing apparatus. In the following description, the flow indicated by the dotted arrow R in FIG. 1 is defined as the transport path, and simply upstream and downstream means upstream and downstream in the transport path.

  As shown in FIGS. 1 to 7, the double-sided stencil printing apparatus 1 according to the first embodiment includes a paper feeding unit 2, a first printing unit 3, an upstream intermediate transport unit 4, a storage unit 5, and a downstream side. An intermediate transport unit 6, a second printing unit 7, a paper discharge unit 8, and a control unit 9 are provided.

  The paper feed unit 2 feeds the stacked printing paper 99. The sheet feeding unit 2 is disposed on the most upstream side of the transport path R. The sheet feeding unit 2 includes a sheet feeding table 11, primary sheet feeding rollers 12 and 12, and secondary sheet feeding rollers 13 and 13. The paper feed tray 11 holds the stacked printing paper 99. The primary paper feed rollers 12, 12 convey the uppermost print paper 99 among the print paper 99 placed on the paper feed tray 11. The secondary paper feed rollers 13 and 13 convey the printing paper 99 conveyed by the primary paper supply roller 12 to the first printing unit 3. The rotation drive of the main motor 85 is transmitted to each of the paper feed rollers 12 and 13 via a paper feed clutch (not shown).

  As shown in FIGS. 1 and 2, the first printing unit 3 prints the first image on the surface 99 a of the printing paper 99 while conveying the printing paper 99. The first printing unit 3 is disposed on the downstream side of the paper feeding unit 2. The first printing unit 3 includes a first drum 15, a first press roll 16, a base paper clamp 17, and a separation claw 18.

  The first drum 15 is rotated in the direction of arrow A together with the stencil sheet 19 by receiving a rotational driving force from the main motor 85. The ink applied to the printing paper 99 is supplied to the first drum 15 through the holes drilled in the stencil sheet 19.

  The first press roll 16 presses the printing paper 99 to the first printing position Pp <b> 1 at the lower end of the first drum 15. The first press roll 16 is moved in the vertical direction by a solenoid device (not shown). Specifically, the first press roll 16 is moved between a pressing position capable of pressing the printing paper 99 shown by a solid line in FIG. 2 and a separating position shown by a one-dot chain line in FIG. During the printing operation, the first press roll 16 is disposed at the pressing position when printing, and is disposed at the separated position when avoiding the base paper clamp 17.

  The base paper clamp 17 clamps the front end of the stencil base paper 19. The base paper clamp 17 is provided on a part of the outer peripheral portion of the first drum 15.

  The separation claw 18 peels off the printing paper 99 printed by the first drum 15 from the first drum 15. The separation claw 18 is disposed above the downstream side of the first printing position Pp1. The tip of the separation claw 18 is disposed at a position where it can be inserted between the first drum 15 and the printing paper 99.

  The upstream intermediate conveyance unit 4 conveys the printing paper 99 printed by the first printing unit 3 to the storage unit 5. The upstream intermediate transport unit 4 is disposed on the downstream side of the first printing unit 3. The upstream intermediate conveyance unit 4 includes four pulleys 21 arranged in an arc shape, a conveyance belt 22 hung on the four pulleys 21, and a suction fan 23 that causes the conveyance belt 22 to suck the printing paper 99. I have. A plurality of suction holes (not shown) through which the airflow generated by the suction fan 23 passes are formed in the transport belt 22.

  The storage unit 5 temporarily holds and discharges the printing paper 99 printed by the first printing unit 3 so as to be reversed and conveyed to the second printing unit 7 via the downstream intermediate conveyance unit 6. Paper. As shown in FIG. 1, the reservoir 5 is disposed between the first printing unit 3 and the second printing unit 7 on the transport path R. As shown in FIG. 2, the reservoir 5 includes a carry-in guide plate 31, a carry-in device 32, a clamp device 33, a discharge-side guide plate 34, and a discharge device 35.

  The carry-in side guide plate 31 guides the printing paper 99 carried into the storage unit 5 to the clamp device 33. The carry-in side guide plate 31 is disposed across the vicinity of the discharge side end of the upstream intermediate transport unit 4 and the vicinity of the carry-in end of the clamp device 33.

  The carry-in device 32 conveys the printing paper 99 conveyed from the upstream intermediate conveyance unit 4 to the clamp device 33 while sucking the printing paper 99. The carry-in device 32 is disposed outside the middle portion of the carry-in side guide plate 31. The carry-in device 32 includes a pair of pulleys 36, 36, a conveyance belt 37 that is hung over the pair of pulleys 36, 36 and rotated in the conveyance direction, and a suction fan 38 that causes the conveyance belt 37 to suck the printing paper 99. It has.

  The clamp device 33 temporarily clamps the plurality of printing sheets 99 conveyed from the carry-in device 32 and conveys them to the discharge device 35. As shown in FIGS. 3 to 6, the clamp device 33 includes a pair of pulleys 41 and 42, a clamp conveyance belt 43, a plurality of clamp claws 44, and detection electrodes 45 and 46.

  The pair of pulleys 41 and 42 are rotationally driven by the rotational driving force transmitted from the clamping device motor.

  The clamp conveyance belt 43 conveys the clamp claw 44 while holding it. The clamp conveyor belt 43 is hung across a pair of pulleys 41 and 42. The clamp conveyance belt 43 is driven by the rotational drive of the pulleys 41 and 42. The clamp conveying belt 43 is formed with holding holes (not shown) for holding the clamp claws 44 at equal intervals.

  As shown in FIGS. 3 and 5, the clamp claw 44 clamps (holds) the printing paper 99 with the adjacent clamp claw 44. The interval between the adjacent clamp claws 44 and the clamp claws 44 is configured to be changeable by pulleys 41 and 42 and the clamp conveyance belt 43. A flat electrode 47 is provided on one side surface of the clamp claw 44. A leaf spring electrode 48 is provided on the other side surface of the clamp claw 44. The tip 48 a of the leaf spring electrode 48 is bent toward the flat electrode 47 of the adjacent clamp claw 44.

  As shown in FIG. 6, in a state where the printing paper 99 is not clamped, the distance d1 between the adjacent clamp claws 44 and the clamp claws 44 at the positions P1 to P9 in the clamp area A1 is the tip of the leaf spring electrode 48. 48 a is set so as to be in contact with the adjacent planar electrode 47. As a result, as shown in FIG. 5, in the clamp region A <b> 1, the printing paper 99 is clamped by the plate spring electrode 48 of the clamp claw 44 adjacent to the planar electrode 47 of the clamp claw 44.

  On the other hand, the distance d2 between the pair of clamp claws 44 and the clamp claws 44 at the position P10 and the position P1 in the carry-in area A2 is the distance between the flat electrode 47 of the clamp claws 44 and the distal end portion 48a of the leaf spring electrode 48 of the clamp claws 44. Is set wider than the distance d1 between the pair of clamp claws 44 and the clamp claws 44 in the clamp area A1. The printing paper 99 that is carried in reaches deeper than the tip 48 a of the leaf spring electrode 48.

  The distance d3 between the pair of clamp claws 44 and the clamp claws 44 at the positions P9 and P11 in the discharge area A3 is such that the flat electrode 47 of the clamp claws 44 and the tip 48a of the leaf spring electrode 48 of the clamp claws 44 adjacent to each other. The distance d1 between the pair of clamp claws 44 and the clamp claws 44 in the clamp area A1 is set so as not to contact. Thereby, the discharged printing paper 99 is easily discharged.

  The pair of detection electrodes 45 and 46 detect an electrical change (change in voltage) between the flat electrode 47 of the clamp claw 44 at the position P1 and the leaf spring electrode 48 of the clamp claw 44 at the adjacent position P2. It is for output. The detection electrode 45 is fixed so as to be connected to the flat electrode 47 of the clamp claw 44 on the most upstream side of the clamp region A1. The detection electrode 46 is fixed so as to be connected to the leaf spring electrode 48 of the clamp claw 44 at the position P2 in the clamp region A1. As shown in FIG. 4, the detection electrode 45 (46) includes an elastic part 51 (55), a holding part 52 (56), and a wiring 53 (57).

  The elastic part 51 (55) is made of an elastically deformable metal. The distal end portion of the elastic portion 51 of the detection electrode 46 is disposed at a position in contact with the planar electrode 47 of the clamp claw 44 in the clamp region A1. The distal end portion of the elastic portion 55 of the detection electrode 46 is disposed at a position in contact with the leaf spring electrode 48 of the clamp claw 44 in the clamp region A1.

  The holding part 52 (56) is made of an insulating resin. The holding portion 52 (56) holds the rear end portion of the elastic portion 51 (55).

  The wiring 53 (57) is electrically connected to the elastic part 51 (55) inside the holding part 52 (56). The wiring 53 is connected to a switching unit 93 of a voltage application unit 87 described later. The wiring 57 is grounded inside the voltage application unit 87.

  Here, as shown in FIG. 5, when the printing paper 99 is clamped by the clamp pawl 44 and the clamp pawl 44, the flat electrode 47 of the clamp pawl 44 and the leaf spring electrode 48 of the clamp pawl 44 are insulated. Is done. Thereby, the detection electrode 45 and the detection electrode 46 are also insulated.

  On the other hand, as shown in FIG. 6, when the printing paper 99 is not clamped by the clamp pawl 44 and the clamp pawl 44, the planar electrode 47 of the clamp pawl 44 and the leaf spring electrode 48 of the clamp pawl 44 are short-circuited. Thereby, the detection electrode 45 and the detection electrode 46 are also short-circuited.

  The discharge-side guide plate 34 guides the printing paper 99 discharged from the storage unit 5 to the downstream intermediate transport unit 6. The discharge side guide plate 34 is disposed over the vicinity of the discharge side end of the clamp device 33 and the vicinity of the carry-in side end of the downstream intermediate transport unit 6.

  The discharge device 35 transports the printing paper 99 transported by the clamp device 33 to the downstream intermediate transport unit 6 while sucking the printing paper 99. The discharge device 35 is disposed outside the middle portion of the discharge side guide plate 34. The discharge device 35 includes a pair of pulleys 59 and 59, a conveyance belt 60 that is hung over the pair of pulleys 59 and 59 and rotated in the conveyance direction, and a suction fan 61 that causes the conveyance belt 60 to suck the printing paper 99. It has.

  The downstream intermediate transport unit 6 transports the printing paper 99 transported from the storage unit 5 to the second printing unit 7. The downstream intermediate transport unit 6 is disposed on the downstream side of the storage unit 5. The downstream intermediate transport unit 6 includes two pairs of pulleys 62, 62, 63, 63, an arcuate guide plate 64, and a paper detection sensor 89.

  The pair of pulleys 62 and 62 convey the printing paper 99 conveyed from the storage unit 5 to the pair of pulleys 63 and 63 while sandwiching the printing paper 99. The pair of pulleys 63, 63 conveys the printing paper 99 conveyed from the pair of pulleys 62, 62 to the second printing unit 7 along the guide plate 64.

  The second printing unit 7 prints the second image on the back surface 99 b of the printing paper 99 while conveying the printing paper 99. The second printing unit 7 is disposed on the downstream side of the downstream intermediate transport unit 6. The second printing unit 7 includes a second drum 65, a second press roll 66, a base paper clamp 67, and a separation claw 68.

  The second drum 65 is rotated in the direction of arrow B together with the stencil sheet 69 by receiving a rotational driving force from the main motor 85. The ink applied to the printing paper 99 is supplied to the second drum 65 through a hole formed in the stencil sheet 69.

  The second press roll 66 presses the printing paper 99 to the second printing position Pp <b> 2 at the lower end of the second drum 65. The second press roll 66 is moved in the vertical direction by a solenoid device (not shown). Specifically, the second press roll 66 is moved between a pressing position where the printing paper 99 shown by a solid line in FIG. 2 can be pressed and a separation position shown by a one-dot chain line in FIG. During the printing operation, the second press roll 66 is disposed at the pressing position when printing, and is disposed at the separated position when avoiding the base paper clamp 67.

  The base paper clamp 67 clamps the tip of the stencil base paper 69. The base paper clamp 67 is provided on a part of the outer peripheral portion of the second drum 65.

  The separation claw 68 is for peeling off the printing paper 99 printed by the second drum 65 from the second drum 65. The separation claw 68 is disposed above the downstream side of the second printing position Pp2. The tip of the separation claw 68 is disposed at a position where it can be inserted between the second drum 65 and the printing paper 99.

  The paper discharge unit 8 includes a belt conveyance mechanism 70 and a paper discharge stand 71. The belt conveyance mechanism 70 conveys the printing paper 99 peeled from the second drum 65. On the paper discharge table 71, the printing paper 99 which has been printed on both sides or has been printed on both sides by the belt conveyance mechanism 70 is placed.

  Next, the control system of the double-sided stencil printing apparatus 1 of the first embodiment will be described with reference to FIG.

  The control unit 9 is responsible for overall control of the double-sided stencil printing apparatus 1. The control unit 9 includes a CPU 81 that performs various calculations, a ROM 82 that stores programs, a RAM 83 that temporarily stores information, and an I / O port 84 that performs input and output. Yes.

  An operation panel 88 through which a user inputs various instructions is connected to the I / O port 84 of the control unit 9. The I / O port 84 of the control unit 9 includes a motor driver 86a for controlling the main motor 85, fan drivers 86b, 86c and 86d for controlling the suction fans 23, 38 and 53, and a voltage application unit. 87 is connected.

  The voltage application unit 87 applies a voltage to the detection electrodes 45 and 46. The voltage application unit 87 includes a low voltage unit 91, a high voltage unit 92, and a switching unit 93. The low voltage unit 91 applies a low voltage (for example, 5 V) between the detection electrodes 45 and 46. The high voltage unit 92 applies a high voltage between the detection electrodes 45 and 46. The switching unit 93 switches the connection destination of the detection electrode 45 between the low voltage unit 91 and the high voltage unit 92. Here, the switching unit 93 first connects the low voltage unit 91 and the detection electrode 45. The switching unit 93 connects the high-voltage unit 92 and the detection electrode 45 when the detection electrodes 45 and 46 are insulated by the printing paper 99. In a state where the high voltage unit 92 and the detection electrode 45 are connected, the control unit 9 analyzes the voltage between the detection electrodes 45 and 46 to determine the quality of the printing paper 99 and the type of ink applied. .

  Next, a printing operation of the double-sided stencil printing apparatus 1 according to the first embodiment described above will be described with reference to the drawings. FIG. 8 is a flowchart for explaining the printing operation. 9 to 11 are partially enlarged views for explaining the conveyance of the printing paper in the clamping device. 9-11, the code | symbol 44a, 44b is provided to the clamp nail | claw of description object. In FIGS. 9 to 11, reference numeral 99A is given to the printing paper to be explained and is shown by a thick solid line.

  First, when the user operates the print button on the operation panel 88 (S1: Yes), the control unit 9 performs initial setting (S2). Here, the initial setting includes a process of winding the stencil sheets 19 and 65 around the drums 15 and 61, a process of connecting the detection electrode 45 to the low pressure unit 91 by the switching unit 93, and the like.

  Next, the control unit 9 drives the suction fans 23, 38, 61 via the fan drivers 86b, 86c, 86d (S3). Thereby, a suction force is generated in each of the conveyor belts 22, 37, 52.

  Thereafter, the control unit 9 drives each motor such as the clamping device motor and the main motor 85 (S4).

  As a result, the paper feed rollers 12 and 13 are driven to rotate, and the uppermost print paper 99 among the print papers 99 placed on the paper feed tray 11 passes through the transport path R to the first printing unit 3. Paper is fed. Next, when the printing paper 99 reaches the first printing position Pp1, it is pressed by the first drum 15 and the first press roll 16. Thus, the printing paper 99 is conveyed to the upstream intermediate conveyance unit 4 while an image is printed on the surface 99a by the first drum 15 rotated in the direction of arrow A.

  Next, when the printing paper 99 reaches the upstream intermediate conveyance unit 4, the printing paper 99 is sucked by the conveyance belt 22 and conveyed to the storage unit 5.

  As shown in FIG. 9, the printing paper 99A conveyed to the reservoir 5 is first inserted between the clamp claws 44a and 44b arranged at the position P10 and the position P1 of the carry-in area A2. Here, since the distance d2 between the clamp claw 44a at the position P10 and the clamp claw 44b at the position P1 is wider than the distance d1 in the clamp area A1, the lower end of the printing paper 99A is the tip of the leaf spring electrode 48. It reaches deeper than 48a.

  Next, as shown in FIG. 10, the clamp claws 44 a and 44 b are moved along the arrow C direction together with the clamp conveyance belt 43. When the clamp claws 44a and 44b reach the position P1 and the position P2 of the clamp area A1, the distance between the clamp claws 44a and 44b is reduced to “d1”. As a result, the printing paper 99A is clamped by the flat electrode 47 of the clamp claw 44a at the position P1 and the tip 48a of the leaf spring electrode 48 of the clamp claw 44b at the position P2.

  As shown in FIGS. 4 and 5, the planar electrode 47 and the detection electrode 45 of the clamp claw 44a at the position P1 are electrically connected. The leaf spring electrode 48 of the clamp pawl 44b at the position P2 and the detection electrode 46 are electrically connected. Since the flat electrode 47 of the clamp claw 44a at the position P1 and the leaf spring electrode 48 of the clamp claw 44b at the position P2 are electrically insulated by the clamped printing paper 99A, the detection electrodes 45 and 46 are detected. Is also insulated.

  Here, the detection electrode 45 and the detection electrode 46 to which a low voltage is applied from the low voltage unit 91 of the voltage application unit 87 outputs an electrical signal to the control unit 9. Thereby, the control unit 9 determines that the printing paper 99A is clamped by the clamp claws 44a and 44b (S5: Yes).

  Next, the control unit 9 controls the switching unit 93 to connect the detection electrode 45 and the high voltage unit 92 (S6). As a result, a high voltage is applied between the detection electrode 45 and the detection electrode 46 by the high voltage unit 92. Then, the voltage application unit 87 outputs the voltage between the detection electrodes 45 and 46 to the control unit 9 as an electric signal.

  Next, the control unit 9 analyzes the voltage of the electrical signal input from the voltage application unit 87 (S7). Thereby, the control unit 9 determines which kind of the printing paper 99A, the ink applied to the printing paper 99A, or the like is.

  Next, the control unit 9 prepares for the next printing paper 99 and controls the switching unit 93 to connect the detection electrode 45 and the low voltage unit 91 (S8).

  Thereafter, as shown in FIG. 11, the clamp claws 44a and the clamp claws 44b are further moved along the arrow C direction while clamping the printing paper 99A. Then, the clamp claws 44a and the clamp claws 44b reach the position P9 and the position P11 of the discharge area A3. Thereby, the space | interval of the clamp nail | claw 44a and the clamp nail | claw 44b spreads, and becomes "d3". As a result, the clamping of the printing paper 99A by the flat electrode 47 of the clamp claw 44a at the position P9 and the tip 48a of the leaf spring electrode 48 of the clamp claw 44b at the position P11 is released.

  Next, the printing paper 99 is sucked by the conveyance belt 60 of the discharge device 35 while being guided by the discharge side guide plate 34, and is conveyed to the downstream intermediate conveyance unit 6.

  Next, in the downstream intermediate transport unit 6, when the printing paper 99 is detected by the paper detection sensor 89 (S10: Yes), the printing process is continued. Accordingly, the printing paper 99 is conveyed to the second printing unit 7 by the downstream intermediate conveyance unit 6.

  Next, when the printing paper 99 reaches the second printing position Pp2, the second printing unit 7 prints an image on the back surface 99b of the printing paper 99 by the stencil sheet 69 wound around the second drum 65. Then, the printing paper 99 is conveyed to the paper discharge unit 8 by the second drum 65 and the second press roll 66. Thereby, printing of the printing paper 99 is completed.

  Here, when it is determined that the predetermined number of sheets has not been printed (S10: Yes), the control unit 9 returns to step S5 and repeats the printing process. Conversely, when it is determined that the predetermined number of sheets have been printed (S10: No), the controller 9 performs various print end processes and ends the print process.

  On the other hand, as shown in FIG. 6, when the printing paper 99 is not clamped by the clamp claw 44 and the adjacent clamp claw 44, the front end portion 48 a of the flat electrode 47 of the clamp claw 44 and the leaf spring electrode 48 of the clamp claw 44. Are short-circuited. Thereby, when the clamp claws 44 and 44 reach the positions P1 and P2, the detection electrode 45 connected to the planar electrode 47 and the detection electrode 46 connected to the leaf spring electrode 48 are also short-circuited. As a result, the voltage between the detection electrode 45 and the detection electrode 46 is substantially “0”. This voltage is output from the voltage applying unit 87 to the control unit 9 as an electrical signal. The control unit 9 determines that the printing paper 99 is not clamped by the clamp claws 44, 44 based on this electrical signal (S5: No).

  Next, the control unit 9 forcibly ends the printing process (S12). Thereafter, the control unit 9 displays an error message and ends.

  In addition, even when the printing paper 99 is not detected by the paper detection sensor 89 of the downstream intermediate transport unit 6 (S9: No), the control unit 9 performs the processes of steps S12 and S13 and ends the printing process.

  As described above, since the double-sided stencil printing apparatus 1 according to the first embodiment includes the detection electrodes 45 and 46, the printing paper 99 is clamped to the clamp claws 44 and 44 in the clamp area A1. It is possible to detect an electrical change in a state where it is not. Thereby, the presence or absence of the printing paper 99 between the clamp claws 44 and 44 can be detected. As a result, when the printing paper 99 is not clamped, the printing operation can be forcibly terminated and a failure due to the jamming of the printing paper 99 or the like can be suppressed.

  Further, in the double-sided stencil printing apparatus 1, since the detection electrodes 45 and 46 are fixed so as to be connected to the electrodes 47 and 48 of the clamp claws 44 and 44 on the most upstream side of the clamp area A1, the printing paper 99 is It can be detected early that it is not clamped normally.

  Further, in the double-sided stencil printing apparatus 1, the mechanical resistance to the clamp claws 44, 44 connected to the detection electrodes 45, 46 is reduced by providing the elastic portions 51, 55 at the tips of the detection electrodes 45, 46. Can do.

  In addition, in a technique for detecting the presence or absence of printing paper using light, such as a reflective sensor, light is reflected when the printing paper is clamped to one of the clamping claws. Judge that there is. That is, in such a reflective sensor, it is determined that there is print paper even when the print paper is not clamped by any one of the pair of clamp claws. On the other hand, the double-sided stencil printing apparatus 1 can sequentially detect the presence or absence of the printing paper 99 between the clamp claws 44 and 44 that are sequentially moved to the most upstream side of the clamp area A1. Thereby, even if the printing paper 99 is not clamped between any of the clamp claws 44, 44, it can be detected that the printing paper 99 is not clamped.

(Second Embodiment)
Next, a second embodiment in which a part of the above-described embodiment is changed will be described. FIG. 12 is a front view of clamp claws and detection electrodes located on the most downstream side of the clamp region according to the second embodiment.

  As shown in FIG. 12, in the second embodiment, a pair of detection electrodes 45, 46 for detecting a voltage between the clamp claws 44, 44 at positions P1, P2, which are the most upstream side of the clamp region A1, and the clamp region A pair of detection electrodes 45A and 46A for detecting a voltage between the clamp claws 44 and 44 at positions P8 and P9 which are the most downstream side of A1 may be provided. Accordingly, even if the printing paper 99 is detached from the clamp claws 44 and 44 during conveyance by the clamp device 33, it can be detected.

  As mentioned above, although this invention was demonstrated in detail using embodiment, this invention is not limited to embodiment described in this specification. The scope of the present invention is determined by the description of the scope of claims and the scope equivalent to the description of the scope of claims. Hereinafter, modified embodiments in which the above-described embodiment is partially modified will be described.

  For example, in the above-described embodiment, the present invention is applied to the double-sided stencil printing apparatus, but the present invention may be applied to other printing apparatuses.

  In the above-described embodiment, the present invention is applied to the clamping device that clamps the printing paper. However, the clamping device that clamps an insulating planar member such as a storage medium having an insulating resin housing or the like, or the printing paper. You may apply this invention to the stocker apparatus which stocks. Furthermore, the planar member is not limited to an insulator, and may be a member that conducts electricity. For example, if the member has a large resistance, the resistance value between the clamp claws can be changed. By utilizing this, an electrical change may be detected to detect the presence or absence of a planar member.

  In addition, the shape, arrangement, material, numerical value, and the like of each component in the above-described embodiment can be changed as appropriate. For example, the number of detection electrodes may be further increased or may be arranged corresponding to all the clamp claws in the clamp region.

DESCRIPTION OF SYMBOLS 1 Double-sided stencil printing apparatus 3 1st printing part 5 Storage part 7 2nd printing part 9 Control part 33 Clamp apparatus 41, 42 Pulley 43 Clamp conveyance belt 44, 44a, 44b Claw claw 45, 46 Detection electrode 45A, 46A Detection electrode 47 Flat electrode 48 Leaf spring electrode 48a Tip portion 51, 55 Elastic portion 52, 56 Holding portion 53, 57 Wiring 87 Voltage application portion 91 Low pressure portion 92 High pressure portion 93 Switching portion 99, 99A Printing paper 99a Front surface 99b Back surface A1 Clamp region A2 Loading Area A3 Discharge area R Transport path

Claims (5)

A first clamp member;
A second clamp member for clamping a planar member with the first clamp member;
First detection means and second detection means connected to the first clamp member and the second clamp member, and detecting and outputting an electrical change between the first clamp member and the second clamp member A clamping device comprising: the first detection means and the second detection means. The planar member is printing paper,
A first printing unit that prints an image on one side of the printing paper;
A second printing unit for printing an image on the other side of the printing paper;
The clamp apparatus according to claim 1, wherein the second printing is performed by inverting the printing paper disposed between the first printing unit and the second printing unit and printed by the first printing unit. A printing apparatus comprising: a storage unit that conveys the printing unit to the printing unit. The first clamp member has a first electrode on a side surface facing the second clamp member,
The second clamp member is a second electrode provided on a side surface facing the first clamp member, and has the second electrode in contact with the first electrode when printing paper is not clamped. And
The first detection means has a first elastic part connected to the first electrode,
The second detection means has a second elastic part connected to the second electrode,
The first clamp member and the second clamp member are configured to be movable between a clamp region for clamping the printing paper and other regions,
The printing apparatus according to claim 2, wherein the first detection unit and the second detection unit are fixed.   The printing apparatus according to claim 3, wherein the first detection unit and the second detection unit are arranged on the upstream side of the clamp region. A third detector and a fourth detector for detecting and outputting an electrical change between the first clamp member and the second clamp member;
The third detection means has a first elastic part connected to the first electrode,
The fourth detection means has a second elastic part connected to the second electrode,
The printing apparatus according to claim 4, wherein the third detection unit and the fourth detection unit are fixed to the downstream side of the clamp region with respect to the first detection unit and the second detection unit. .