JP5123706B2 - Stencil printing machine - Google Patents

Description

  The present invention relates to a stencil printing apparatus.

Conventionally, as a stencil printing apparatus, a stencil sheet made by a stencil unit is conveyed by a stencil sheet feeding roll, and a stencil sheet is conveyed by clamping a leading end portion in a conveyance direction of the stencil sheet by a clamp unit provided on a plate cylinder. A stencil printing apparatus for mounting a stencil on a plate cylinder is described (for example, see Patent Document 1). In this stencil printing apparatus, the clamp portion includes a pedestal portion having a magnet portion and a clamp opening / closing member that opens and closes with respect to the pedestal portion. When the clamp opening / closing member is closed by making the shape of the magnet portion a chevron shape The stencil sheet is clamped by the clamp opening / closing member in a normal state.
Japanese Patent Laid-Open No. 2002-79734

  However, in the stencil printing apparatus as described above, when the stencil sheet is transferred from the stencil sheet feeding roll as the conveying means to the clamping unit of the plate cylinder, the front side of the stencil sheet in the conveying direction is clamped by the clamping unit. It is floating in the air. At this time, the stencil sheet is in a slack state. When the stencil sheet is clamped with the clamp opening / closing member in this state, wrinkles are formed on the stencil sheet, or the stencil sheet is clamped obliquely with respect to the plate cylinder. As a result, the stencil sheet may not be properly mounted on the plate cylinder, which may cause image formation failure.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a stencil printing apparatus capable of reliably mounting a conveyed stencil sheet on a plate cylinder and preventing image formation defects.

  The stencil printing apparatus according to claim 1, comprising: a stencil sheet made by a stencil making unit; a conveying unit that has a driving roller that can freely rotate forward and reverse; and that conveys the stencil sheet by forward rotation of the driving roller; A plate cylinder disposed downstream of the stencil sheet in the conveying direction of the stencil sheet and to which the stencil sheet is mounted; and a leading end side of the stencil sheet that is provided in the stencil sheet and conveyed by the conveying unit is held. Clamp means having a main clamp plate for mounting the stencil sheet on the plate cylinder, and holding the stencil sheet provided on the clamp means and transported by the transport means, and by reverse rotation of the drive roller, the stencil sheet And holding means for allowing the base paper to move upstream in the transport direction and applying tension to the stencil paper between the transport means and the plate cylinder.

  A second aspect of the present invention is the stencil printing apparatus according to the first aspect, wherein the holding means has a pre-clamp plate disposed downstream of the main clamp plate in the conveying direction of the stencil sheet. The main clamp plate holds the stencil sheet to which tension is applied by the pre-clamp plate holding the stencil sheet.

  The invention described in claim 3 is the stencil printing apparatus according to claim 2, wherein the holding force of the main clamp plate to the stencil sheet is higher than the holding force of the pre-clamp plate to the stencil sheet. And

  A fourth aspect of the present invention is the stencil printing apparatus according to the second or third aspect, wherein an opening height of the pre-clamp plate is larger than an opening height of the main clamp plate.

  ADVANTAGE OF THE INVENTION According to this invention, there exists an effect that the conveyed stencil sheet | seat can be reliably mounted | worn to a plate cylinder, and the stencil printing apparatus which can prevent the image formation defect can be provided.

  A stencil printing apparatus according to an embodiment of the present invention will be described with reference to FIGS.

  The stencil printing apparatus 1 according to the present embodiment includes a stencil sheet 5 made by the plate making unit 3 and a master transport roller 7 as a drive roller that can freely rotate in the forward and reverse directions. 5, a conveying unit 9 that conveys 5, a plate cylinder 11 that is disposed downstream of the conveying unit 9 in the conveying direction of the stencil sheet 5, and on which the stencil sheet 5 is mounted, and is conveyed by the conveying unit 9 provided in the plate cylinder 11 A stencil sheet 15 having a main clamp plate 13 for holding the front end side in the transport direction of the stencil sheet 5 and mounting the stencil sheet 5 on the plate cylinder 11; Holding means 17 that allows the stencil sheet 5 to move upstream in the transport direction by reverse rotation of the master transport roller 7 and applies tension to the stencil sheet 5 between the transport means 9 and the plate cylinder 11. Have That.

  The holding means 17 has a pre-clamp plate 19 disposed downstream of the main clamp plate 13 in the conveying direction of the stencil sheet 5. The main clamp plate 13 holds the stencil sheet 5 by the pre-clamp plate 19. By doing so, the stencil sheet 5 to which tension is applied is held.

  Further, the holding force of the main clamp plate 13 with respect to the stencil sheet 5 is set higher than the holding force of the pre-clamp plate 19 with respect to the stencil sheet 5.

  The opening height of the pre-clamp plate 19 is set to be larger than the opening height of the main clamp plate 13.

  As shown in FIGS. 1 to 5, the stencil sheet 5 is formed in a long shape and is wound in a roll shape. The stencil sheet 5 is made by the plate making unit 3 based on the electrical signal and instructions for enlargement / reduction, etc., based on information obtained by optically reading the document by a document reading unit (not shown).

  The plate making unit 3 is disposed on the downstream side in the transport direction of the stencil sheet 5 wound in a roll shape, and includes a thermal head 21. The thermal head 21 selectively selects a large number of heating elements based on the original information of the original reading section with respect to the stencil sheet 5 conveyed by a tension roll 23 and a platen roll 25 rotated by a drive motor (not shown). By operating, heat-sensitive perforation is performed. The stencil sheet 5 thus made is cut at a predetermined location by a stencil sheet cutter (not shown) and conveyed to the conveying means 9.

  The conveying means 9 is arranged on the downstream side in the conveying direction of the stencil sheet 5 with respect to the plate making unit 3, and includes a pair of master conveying rollers 7 and a pair of plate receiving rollers 27. One of the pair of master transport rollers 7 is rotated by a master transport motor (not shown) that can be rotated in the forward rotation for transporting the stencil sheet 5 that has been made and the reverse rotation that pulls back the stencil sheet 5 that has been made. Driven. The stencil sheet 5 transported to the transport means 9 is transported to the plate cylinder 11 via the plate roller 27 by the normal rotation of the master transport roller 7.

  The plate cylinder 11 is rotatably arranged on the downstream side in the transport direction of the stencil sheet 5 with respect to the transport means 9, and the outer peripheral surface thereof is generally constituted by an ink-permeable and flexible screen 29. Inside the plate cylinder 11 is provided an inner unit (not shown) having an intermediate push roll for supplying ink. Ink is supplied to the inner periphery of the screen 29 by this inner unit. In addition, an impression cylinder (not shown) is rotatably provided below the plate cylinder 11, and the intermediate pressing roll presses the screen 29 to be in pressure contact with the impression cylinder. A printing medium (not shown) is conveyed between the impression cylinder and the plate cylinder 11, the screen 29 and the stencil sheet 5 are pressed by the intermediate pressing roll and the impression cylinder, and ink is ejected from the holes formed in the stencil sheet 5. An image is formed by being transferred to a print medium. In such a plate cylinder 11, the stencil sheet 5 made by the clamping means 15 is clamped and the stencil sheet 5 is wound around the outer periphery.

  The clamp means 15 is provided on the plate cylinder 11 and includes a main clamp plate 13 and a holding means 17. The main clamp plate 13 is formed of a flexible magnetic material, and is provided on the clamp body 31 so as to be openable and closable with respect to the clamp magnet 35 on the plate cylinder 11 side at a main clamp fulcrum 33. A main clamp roller 37 is provided on the main clamp plate 13. The main clamp roller 37 is actuated by a main clamp cam 39 that moves far and away with respect to the plate cylinder 11. The main clamp roller 37 is pushed down by the main clamp cam 39 to open the main clamp plate 13 by this action. The main clamp cam 39 is provided with a position sensor (not shown) and is driven by a cam motor (not shown). The stencil sheet 5 made with the main clamp plate 13 opened is inserted between the main clamp plate 13 and the clamp magnet 35, the main clamp plate 13 is closed, and the stencil sheet 5 is clamped, and the plate cylinder 11 Is rotated to wind the stencil sheet 5 around the plate cylinder 11. The slackness of the stencil sheet 5 at the time of clamping is corrected by the holding means 17.

  The holding means 17 has a pre-clamp plate 19 disposed on the downstream side in the transport direction of the stencil sheet 5 with respect to the main clamp plate 13. The pre-clamp plate 19 is formed of a flexible magnetic material, and is provided on the clamp body 31 so as to be openable and closable with respect to the clamp magnet 35 on the plate cylinder 11 side at a pre-clamp fulcrum 41. The pre-clamp plate 19 is provided with a pre-clamp roller 43, which is actuated by a pre-clamp cam 45 that moves to and away from the plate cylinder 11, and pushes down the pre-clamp roller 43 with the pre-clamp cam 45. Thus, the pre-clamp plate 19 is opened by this action. The pre-clamp cam 45 is provided with a position sensor (not shown) and is driven by a cam motor. The opening height of the pre-clamp plate 19 is set to be larger than the opening height of the main clamp plate 13, and the front end side in the transport direction of the stencil sheet 5 inserted between the main clamp plate 13 and the clamp magnet 35 is the pre-clamp plate. The stencil sheet 5 is inserted between the pre-clamp plate 19 and the clamp magnet 35 in a reliable manner. The opening height of the main clamp plate 13 refers to the distance between the main clamp plate 13 and the clamp magnet 35 on the downstream (outlet) side in the insertion direction in which the stencil sheet 5 is inserted between the main clamp plate 13 and the clamp magnet 35. It is not necessary to set the opening height of the pre-clamp plate 19 larger than the opening height of the main clamp plate 13 upstream (inlet) in the insertion direction, and the opening of the main clamp plate 13 downstream in the insertion direction What is necessary is just to set larger than height.

  Further, the holding force of the pre-clamp plate 19 with respect to the stencil sheet 5 is set so that the holding force of the main clamp plate 13 with respect to the stencil sheet 5 is also small. The holding force of the pre-clamp plate 19 is set to such an extent that the stencil sheet 5 can be pulled back by reverse rotation of the master conveying roller 7 with the stencil sheet 5 clamped by the pre-clamp plate 19. Thus, tension is applied to the stencil sheet 5 between the transport means 9 (plate roller 27) and the plate cylinder 11 by reversely rotating the master transport roller 7 with the pre-clamp plate 19 clamping the stencil sheet 5. can do. Thus, the slackness of the stencil sheet 5 can be corrected by applying tension to the stencil sheet 5. Note that the stencil sheet 5 is pulled back by the reverse rotation of the master transport roller 7 so that the stencil sheet 5 does not come out from between the pre-clamp plate 19 and the clamp magnet 35. Further, the holding force of the pre-clamp plate 19 uses a member having a material different from that of the main clamp plate 13 such as a magnetic material having a lower magnetic force than the main clamp plate 13 or a member having a smaller friction than the main clamp plate 13. You only have to set it.

  In the stencil printing apparatus 1 configured as described above, the stencil sheet 5 made by the plate making unit 3 is conveyed to the conveying unit 9 and conveyed to the plate cylinder 11 side by the normal rotation of the master conveying roller 7. A predetermined amount of the conveyed stencil sheet 5 is sent out between the main clamp plate 13 and the clamp magnet 35 by the normal rotation of the master transport roller 7 to the space between the pre-clamp plate 19 and the clamp magnet 35. It is clamped by the clamp plate 19. While the stencil sheet 5 is held by the pre-clamp plate 19, the master transport roller 7 is reversely rotated, the stencil sheet 5 is pulled back, and tension is applied to the stencil sheet 5 between the transport means 9 and the plate cylinder 11. The stencil sheet 5 to which this tension is applied is clamped by the main clamp plate 13. By such an operation, the slack of the stencil sheet 5 floating in the air between the conveying means 9 and the plate cylinder 11 is corrected, and the stencil sheet 5 to which tension is applied is clamped by the main clamp plate 13 to thereby stencil sheet. It is possible to prevent plate-forming defects of the stencil sheet 5 such as wrinkles formed on the stencil sheet 5 and the stencil sheet 5 being clamped obliquely with respect to the plate cylinder 11.

  Here, the operation timing of the master conveyance motor that drives the master conveyance roller 7 and the cam motor that drives the pre-clamp cam 45 and the main clamp cam 39 will be described.

  First, the pre-clamp cam 45 and the main clamp cam 39 in the raised state are lowered by the cam motor (see FIG. 4A), and the pre-clamp plate 19 and the main clamp plate 13 are opened. Next, the master transport motor is driven to rotate in the forward direction and the stencil sheet 5 is transported between the pre-clamp plate 19 and the clamp magnet 35 via the main clamp plate 13 and the clamp magnet 35 (FIG. 3). (See (a)). Next, the cam motor is driven to raise the pre-clamp cam 45 (see FIG. 4B), and the stencil sheet 5 is clamped by the pre-clamp plate 19 (see FIG. 3B). Next, with the stencil sheet 5 held by the pre-clamp plate 19, the master transport motor is driven in the reverse direction to pull back the stencil sheet 5 and apply tension to the stencil sheet 5 between the transport means 9 and the plate cylinder 11. (See FIG. 3C). Finally, the cam motor is driven to raise the main clamp cam 39 (see FIG. 4C), and the stencil sheet 5 is clamped by the main clamp plate 13 (see FIG. 3D).

  In such a stencil printing apparatus 1, the stencil sheet 5 transported by the transport unit 9 is held, and the stencil sheet 5 is allowed to move upstream in the transport direction by the reverse rotation of the master transport roller 7. Since the holding means 17 for applying tension to the stencil sheet 5 is provided between the cylinder 11 and the stencil sheet 5, the stencil sheet 5 to which tension is applied is clamped by the main clamp plate 13, so that a crease is formed on the stencil sheet 5. In other words, it is possible to prevent the stencil sheet 5 from being poorly fixed such that the stencil sheet 5 is clamped obliquely with respect to the plate cylinder 11.

  Therefore, the conveyed stencil sheet 5 can be securely attached to the plate cylinder 11 and image formation defects can be prevented.

  Further, since the holding force of the main clamp plate 13 with respect to the stencil sheet 5 is set higher than the holding force of the pre-clamp plate 19 with respect to the stencil sheet 5, the stencil sheet 5 does not come off from the main clamp plate 13 and is sure. The stencil sheet 5 can be attached to the plate cylinder 11.

  Furthermore, since the opening height of the pre-clamp plate 19 is set to be larger than the opening height of the main clamp plate 13, the leading end side in the transport direction of the stencil sheet 5 inserted between the main clamp plates 13 is the pre-clamp plate 19. The stencil sheet 5 can be reliably inserted between the pre-clamp plates 19.

  In this embodiment, the holding means is a pre-clamp plate. However, the present invention is not limited to this, and suction means for sucking the stencil sheet to the plate cylinder side may be applied. In this case, the suction force is set to such an extent that the stencil sheet can be moved upstream in the transport direction by the reverse rotation of the drive roller.

  The holding means is arranged downstream of the main clamp plate in the conveying direction of the stencil sheet, but tension is applied to the stencil sheet between the conveying means and the plate cylinder to hold the stencil sheet with the main clamp plate. Any position that can be used may be used.

It is a side view of the stencil printing apparatus of one embodiment. It is an enlarged view of the clamp means of one Embodiment. (A) It is a figure of the state which the main clamp board and the pre clamp board opened. (B) It is a figure of the state which only the pre clamp board closed. (C) It is the figure which reversely rotated the master conveyance roller. (D) It is a figure of the state which the main clamp board and the pre clamp board closed. (A) It is a figure of a main clamp cam and a pre clamp cam in a descent state. (B) Only the pre-clamp cam is in a raised state. (C) The main clamp cam and the pre-clamp cam are in a raised state. It is a figure which shows the timing of an operation | movement with a master conveyance motor and a cam motor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Stencil printing apparatus 3 ... Plate making part 5 ... Stencil base paper 7 ... Master conveyance roller 9 ... Conveyance means 11 ... Plate cylinder 13 ... Main clamp plate 15 ... Clamp means 17 ... Holding means 19 ... Pre clamp plate

Claims (4)

A stencil sheet made by the plate making section;
A conveying means for conveying the stencil sheet by a normal rotation of the driving roller, the driving roller having a forward and reverse rotating freely;
A plate cylinder on which the stencil sheet is mounted and disposed downstream of the transport unit in the transport direction of the stencil sheet;
Clamping means provided on the plate cylinder and having a main clamp plate for holding the leading end side in the conveying direction of the stencil sheet conveyed by the conveying means, and mounting the stencil sheet on the plate cylinder;
The stencil sheet provided in the clamping means is held by the conveying means, and the stencil sheet is allowed to move upstream in the conveying direction by the reverse rotation of the drive roller. Holding means for applying tension to the stencil sheet between,
A stencil printing apparatus comprising: The stencil printing apparatus according to claim 1,
The holding means has a pre-clamp plate disposed downstream of the main clamp plate in the conveying direction of the stencil sheet, and the main clamp plate is configured such that the pre-clamp plate holds the stencil sheet. A stencil printing apparatus for holding a stencil sheet to which a tension is applied. The stencil printing apparatus according to claim 2,
The stencil printing apparatus, wherein a holding force of the main clamp plate to the stencil sheet is higher than a holding force of the pre-clamp plate to the stencil sheet. The stencil printing apparatus according to claim 2 or 3,
The stencil printing apparatus, wherein an opening height of the pre-clamp plate is larger than an opening height of the main clamp plate.

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