JP2006116913A - Stencil process printing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a stencil process printing device of such a constitution that an ink leakage can be prevented from worsening, while maintaining the releasability of a printing sheet. <P>SOLUTION: This stencil process printing device comprises a rotation-free plate cylinder 7, an ink supply means 7 which supplies ink to the inner peripheral surface of the plate cylinder 7, a jamming member 16 installed in the way that it can freely come into contact with and separate from the outer peripheral surface of the plate cylinder 7, and a sheet supply means 39 which supplies the printing sheet 15 to between the plate cylinder 7 and the jamming member 16. The printing sheet 15 supplied by the paper supply means 39 is brought into contact under pressure with a master 1 on the plate cylinder 7 using the jamming member 16 after winding the manufactured master 1 around the plate cylinder 7 and thus a printing operation is performed by transferring the ink oozing out of a master perforation part to the printing sheet 15. In addition, the device is equipped with an air knife 19 to release the ink-transferred printing sheet 15 from the plate cylinder 7 by a wind pressure and an air flow control means which controls the air flow of a fan 19a of the air knife 19. At the time of printing, the air flow of the fan 19a of the air knife 19 is made variable by temperature to control it to such levels as high temperature≥normal temperature>low temperature. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a stencil printing apparatus that winds a master made on the outer peripheral surface of a plate cylinder to perform printing on printing paper, and more particularly, to a printing cylinder on which ink is transferred with a plate cylinder by air wind pressure. It is related with the air volume control of the fan of the air knife which peels from.

  Conventionally, a rotary plate cylinder having a structure in which a plurality of layers of resin or metal mesh mesh screens are wound around a peripheral surface of a porous support plate, which is a porous support cylindrical body, is provided with a thermoplastic resin film and Japanese paper fiber. Or, using a stencil master with a laminated structure in which a synthetic fiber or a porous support made of Japanese paper and synthetic fiber is bonded, the thermoplastic resin film surface of the master is brought into contact with the heating element of the thermal head. After being heated and perforated, it is wound around the plate cylinder, and after ink is supplied to the master on the plate cylinder by an ink supply means provided inside the plate cylinder, the ink is fed from the sheet feeding unit toward the plate cylinder. By continuously pressing the printed paper against the master on the plate cylinder with a pressing member such as a press roller, the ink is oozed out from the plate cylinder opening and the master perforation and transferred onto the printing paper. Thermal digital stencil printing device has been known that in performing printing.

  In general, in the above-described stencil printing apparatus, printed printing paper is peeled off from the master on the outer peripheral surface of the plate cylinder by a peeling means such as a peeling claw and discharged to a paper discharge unit such as a paper discharge tray. This peeling claw is arranged in the vicinity of the plate cylinder with a slight gap between its tip and the master so as not to damage the master, and is forced between the printing paper and the master on the outer peripheral surface of the plate cylinder. The printing paper is peeled off with intervention. However, if the plate-making image formed on the master has a solid image part, the adhesive strength of the ink to the printing paper is extremely increased and the printing paper cannot be peeled off by the peeling claw, and the printing paper is In other words, there is a problem of so-called “rolling up” in which the peeling operation is not reliably performed due to the fact that the printing paper is stuck on the printing nail or the printing paper is caught on the peeling nail. Therefore, in order to improve the peeling of the printing paper, a stencil printing apparatus provided with a peeling means called an air knife that urges the peeling by blowing air (air) from the tip portion between the master and the printing paper has been proposed. ing.

Conventionally, the peeling means using an air knife has been aimed at peeling the printing paper from the master on the outer peripheral surface of the plate cylinder with the wind pressure of air, and the blowing of air with the air knife drives the fan of the air knife at the start of printing. It is performed by a method in which the air volume is turned on and a constant air volume is constantly blown to a predetermined position, and the air volume is usually set to a predicted maximum air volume.
However, depending on the printing conditions, the maximum air volume may not be required. In this case, useless energy is consumed and unnecessary noise is generated. In consideration of this problem, it has been proposed to preliminarily estimate the magnitude of the adhesion force of the printing paper to the master and give an air volume suitable for the state (see, for example, Patent Document 1). Furthermore, a plurality of air knife fans are provided in the direction (width direction) orthogonal to the direction of travel of the printing paper, and the air volume of each air knife fan is individually adjusted according to the difference in image amount in the width direction of the original image. It has been proposed to control (see, for example, Patent Document 2).

JP-A-9-193526 JP 2004-50564 A

  In general, in a stencil printing apparatus, the ink supplied to the inner peripheral surface of the plate cylinder by the ink supply means oozes out from the perforated part of the master through the opening of the plate cylinder, and is transferred to the printing paper for printing. When the ink oozing out from the opening of the plate cylinder becomes excessive, excess ink starts to accumulate under the master (between the plate cylinder and the master), and is transmitted to the master after the release of printing pressure and gradually toward the rear end of the master. When the head moves beyond the rear end of the master, surplus ink leaks, so-called “bottom leakage” occurs.

The ink used in the stencil printing machine is composed of water, oil, and pigment, and its viscosity changes with temperature. It is hard at low temperatures and soft at high temperatures. For this reason, the ink hardened at a low temperature loses its fluidity and tends to be left as excess ink under the master (between the plate cylinder and the master), and the above-described tail leakage tends to occur.
On the other hand, the ink peeling performance is more difficult to peel as the ink is softer and easier to peel as the ink is harder.

In the stencil printing apparatus, as described above, in order to improve the peeling of the printing paper, a peeling means called an air knife is provided in the vicinity of the printing drum, and the printing paper is peeled off from the master on the outer peripheral surface of the printing drum by air wind pressure. Things have been done. In order to improve the releasability by the air knife, the air volume of the fan is increased according to the image amount, or a plurality of air knife fans are provided in the direction (width direction) perpendicular to the traveling direction of the printing paper. Has been done.
However, when the air volume of the air knife fan is increased, excess ink under the master wound around the plate cylinder is pushed to the master trailing edge by wind pressure at low temperatures, and excess ink leaks from the master trailing edge. Leakage is more likely to occur.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a stencil printing apparatus having a configuration that does not deteriorate ink leakage while maintaining the peelability of printing paper.

In order to achieve the above object, the present invention adopts the following means.
The first means of the present invention includes a rotatable plate cylinder having an opening through which ink oozes, ink supply means for supplying ink to the inner peripheral surface of the plate cylinder, and the outer peripheral surface of the plate cylinder. A master that is made on the outer peripheral surface of the plate cylinder, and includes a pressing member that is detachably provided and a sheet feeding unit that feeds printing paper to a transfer portion between the plate cylinder and the pressing member After the sheet is wound, the printing sheet fed to the transfer unit by the sheet feeding unit is pressed against the master on the plate cylinder by the pressing member, so that the opening of the plate cylinder and the master punching unit In a stencil printing apparatus that performs printing by transferring ink oozed from the printing paper to the printing paper, an air knife that peels the printing paper on which the ink has been transferred from the printing drum with air pressure, and controls the air volume of the fan of the air knife Air volume control means to perform Characterized in that varying the air volume of the air knife fan by temperature (claim 1).

The second means of the present invention is characterized in that, in the stencil printing apparatus of the first means, the air volume of the fan of the air knife is controlled such that high temperature ≧ normal temperature> low temperature (Claim 2).
The third means of the present invention is characterized in that in the stencil printing apparatus of the second means, the air volume of the fan of the air knife is weakened or the fan is stopped at a low temperature (Claim 3).

According to a fourth means of the present invention, in the stencil printing apparatus of the first means, a plurality of fans of the air knife are provided in a direction orthogonal to the conveyance direction of the printing paper, and the air volumes of the plurality of fans are respectively set according to the temperature. Control is performed independently (claim 4).
According to a fifth means of the present invention, in the stencil printing apparatus of the fourth means, the air volume of the fan arranged at least in the center among the plurality of fans of the air knife is controlled as high temperature ≧ normal temperature> low temperature. (Claim 5).
Further, the sixth means of the present invention is characterized in that, in the stencil printing apparatus of the fifth means, at a low temperature, the air volume of at least the fan disposed at the center is weakened or the fan is stopped. 6)

  The seventh means of the present invention is the stencil printing apparatus according to any one of the second, third, fifth and sixth means, wherein the low temperature range is 17 ° C. or lower, the normal temperature is 17 to 26 ° C., and the high temperature is 26 ° C. or higher. (Claim 7).

  The stencil printing apparatus of the present invention is equipped with an air volume control means for controlling the air volume of the air knife fan, and varies the air volume of the air knife fan depending on the temperature during printing, so that an appropriate fan can be used in each of the high temperature, normal temperature, and low temperature ranges. By setting the air volume of the ink, it is possible to prevent the trailing edge of the ink from getting worse while maintaining the peelability of the printing paper.

  In addition, the air knife has a plurality of fans in a direction orthogonal to the conveyance direction of the printing paper, and the air flow of each of the plurality of fans is independently controlled by the temperature. By setting the air volume to an appropriate air volume in each temperature range of high temperature, normal temperature, and low temperature, it is possible to prevent the ink from leaking while maintaining the peelability of the printing paper and useless energy. Consumption and generation of unnecessary noise can be reduced.

  Hereinafter, the best mode for carrying out the present invention will be described in detail based on the embodiments shown in the drawings.

  FIG. 1 is a schematic diagram showing the main part of a stencil printing apparatus according to an embodiment of the present invention. In FIG. 1, the master 1 in the plate making unit 37 has a laminate structure in which a thermoplastic resin film and a porous support made of Japanese paper fiber or synthetic fiber or a mixture of Japanese paper and synthetic fiber are bonded together. Supplied from a master roll 1a wound in a shape. The master roll 1a is rotatably supported by the master roll core 1b by holder means (not shown). The master 1 is pressed by a thermal head 3 having a large number of heating elements by a platen roller 2 rotatably supported on a plate making unit side plate (not shown), and the platen roller 2 is rotated clockwise by a connected step motor (not shown). By being driven to rotate, the master 1 is drawn out from the master roll 1a.

  The thermal head 3 is urged toward the platen roller 2 by a spring member (not shown), and the heat generating element of the thermal head 3 that contacts the master 1 receives image information from an image reading unit (not shown) (or an external device (not shown)). The master 1 is made by thermal perforation by selectively generating heat in accordance with an image signal from a personal computer or the like). On the downstream side of the platen roller 2 in the master conveyance direction, a pair of feed rollers 4 that are rotatably supported while pressed against a plate making unit side plate (not shown) are provided. The speed is set to be slightly faster, and an appropriate tension is applied while sliding with the master 1.

  On the downstream side of the feed roller 4, a cutter 5 made of a guillotine type upper and lower blade (or a rotary blade moving type or the like) that cuts the master 1 made into a plate to an appropriate length is provided. Further, a guide plate 6 is provided on the downstream side of the cutter 5 to guide the leading end of the master 1 that has been perforated and made to the clamping means on the plate cylinder 7 side.

  The above constitutes the plate making unit 37 of the stencil printing apparatus, and a printing unit 38 is provided on the lower left side of the plate making unit 37. In the printing unit 38, a plate cylinder 7 formed by winding a plurality of layers of a porous support cylindrical body and a resin or metal mesh mesh screen (not shown) covering the outer periphery thereof is rotatable about an ink pipe 8 as a support shaft. Is fixed to a flange (not shown) supported by the motor, and a driving force from a drive motor 9 is transmitted by a drive transmission means (gear or the like) (not shown) to be rotated in a clockwise direction. Inside the plate cylinder 7, an ink roller 10 is rotatably supported by an ink roller shaft 10a by a side plate (not shown) fixed to the ink pipe 8, and is driven by a drive transmission means (gear, belt, etc.) not shown. It is rotated in the same direction in synchronization with the barrel 7. A doctor roller 11 is provided with a slight gap from the outer peripheral surface of the ink roller 10, and an ink reservoir 12 is formed in a wedge-shaped space between the ink roller 10 and the doctor roller 11. Ink is supplied to the outer surface of the ink roller 10 in the form of a thin film. The ink supplied to the ink reservoir 12 is sucked from an ink pack or the like provided outside the plate cylinder by an ink supply device (not shown), dropped from the supply hole of the ink pipe 8 to the ink reservoir 12 and kneaded.

  On the surface of the non-opening portion of the plate cylinder 7, a stage 13 made of a magnetic material is provided along one bus bar of the plate cylinder 7. A clamper 14 for fixing the master 1 parallel to the stage 13 is rotatably supported, and the clamper 14 is opened and closed at a predetermined position by an opening / closing device (not shown). The plate cylinder 7 can be engaged and disengaged with an ink pack or the like in the axial direction of the plate cylinder 7 as a unit. Further, a plate cylinder sensor (not shown) for detecting the position of the plate cylinder 7 is provided in the vicinity of the plate cylinder 7 so as to emit trigger information of a sheet feeding device to be described later. A temperature sensor 26 that detects the temperature in the printing apparatus is provided in the vicinity of the plate cylinder 7.

  Below the plate cylinder 7, an arm shaft 16a rotatably supported by a casing side plate (not shown), a press roller arm pair 16b fixed to the arm shaft 16a, and a shaft portion rotated to the press roller arm pair 16b. A press roller 16 as a pressing member that is freely supported is provided. Further, a cam follower (not shown) and a pressure spring as an urging means are provided at the end of the arm shaft 16a, and the arm shaft 16a is rotated via the cam follower by a cam that rotates in synchronization with the plate cylinder 7. The press roller arm pair 16b swings so that the press roller 16 contacts and separates from the plate cylinder 7 at a predetermined position. The press roller 16 is held at a position separated from the plate cylinder 7 as shown in FIG. 1 except when the printing paper is passed by the contact / separation mechanism. When the sheet is passed, the contact / separation mechanism moves to a position indicated by a broken line in the drawing and is pressed against the plate cylinder 7.

  A paper feed unit 39 that feeds the printing paper 15 toward the plate cylinder is disposed below the right side of the plate cylinder 7. The paper feed device 17 of the paper feed unit 39 detects the paper size. A feed tray 17a that can be moved up and down with a sensor, and a front upper portion that is rotatably supported by a casing side plate (not shown), and that separates and feeds the stacked sheets 15 in contact with each other. A paper feed roller 17b as a paper feed device is provided. In addition, the paper 15 separated and fed by the paper feed roller 17 b of the paper feed device 17 is conveyed to the transfer path between the plate cylinder 7 and the press roller 16 in the feed path of the paper feed unit 39 at a timing. For this purpose, there is provided a pair of registration rollers 18 that are rotatably supported at a position facing a housing side plate (not shown). A paper sensor 24 that detects the paper position is provided in the paper feed path between the paper feed roller 35 and the registration roller 18.

On the lower left side of the plate cylinder 7, an air knife 19 is provided in the vicinity of the plate cylinder 7 for separating the printing paper 15 after ink transfer from the surface of the master 1 on the plate cylinder. Although not shown, the air knife 19 is provided with a peeling claw that is rotatably supported. A paper discharge unit 41 is provided on the lower left side of the air knife 19, and the paper discharge unit 41 conveys the paper discharge conveyance device 22 that conveys the printing paper 15 peeled from the plate cylinder 7. A paper discharge sensor 25 for detecting the print paper 15 is provided, and a paper discharge tray on which the print paper 15 conveyed by the paper discharge transport device 22 is discharged and stacked on the downstream side of the paper discharge transport device 22. 23 is provided.
Further, on the upper left side of the plate cylinder 1, there is provided a plate discharging unit 40 including a plate discharging apparatus 20 for peeling the used master 1 after printing from the plate cylinder 1 and a discarding unit 21 for discarding the peeled used master. It has been.

  Next, FIG. 2 is a block diagram showing an example of a control system of the stencil printing apparatus having the above configuration. The main control unit 30 of the control system includes a central processing unit (CPU) 31 composed of a microcomputer, a clock, a timer, and a control circuit, an input / output I / O interface 32, a control program and control information. Stored read-only memory (ROM) 33, operation / display unit (operation unit such as start button, numeric keypad, various setting keys, display unit such as liquid crystal panel, or operation / display unit such as liquid crystal touch panel) Various input / setting information from an operation / display panel 35 and various detections from various sensors (temperature sensor 26, paper size sensor 43, plate cylinder sensor 42, paper sensor 24, paper discharge sensor 24, etc.). A rewritable memory (RAM) 34 in which information is stored, and the like, an image reading unit 36, a plate making unit 37, a printing unit 38, Controls the drive means of each part of the apparatus such as the paper part 39, the plate discharging part 40, the paper discharge part 41, the air knife 19, etc. based on various input / setting information from the operation / display part 35 and various detection information from various sensors. To do.

Next, an example of the operation of the stencil printing apparatus having the above configuration will be described. FIG. 3 is a flowchart showing an example of the control operation of the stencil printing apparatus.
1 to 3, when an operator sets a document on a document table of the image reading unit and presses a start button or the like of the operation / display unit 35, the plate cylinder 7 rotates, and a clamper is operated by an unillustrated opening / closing device. 14 is opened, and the used master at the time of the previous printing is peeled off from the surface of the plate cylinder 7 by the plate discharging device 20 of the plate discharging unit and discarded to the discarding unit 21 (S1). While performing this plate removal processing operation, the plate cylinder 7 rotates and stops until the clamper 14 is in a substantially lateral position on the plate making side. When the plate cylinder 7 is stopped, a document is conveyed onto a document table (not shown) by a document separation / conveyance device (not shown) of the image reading unit 36, and a document image is converted into an electric signal by an image pickup device such as a CCD of the image reading unit 36. The image information is sent to the image processing unit via an A / D converter and the like, converted into binarized image information by the image processing unit, and then temporarily stored in the image memory (S3). The image information once stored in the image memory is transmitted to the plate making unit 37, and the heating elements of the thermal head 3 are energized in pulses in accordance with the image information (image signal), and the width direction of the master 1 (main scanning direction). The plate making process in which the heat sensitive film of the master 1 is heated and punched by rotating the step motor (not shown) and transporting the master 1 in the sub-scanning direction by the platen roller 2 and the feed roller 4 and the like. Is performed (S4).

  After the plate making process, the guide plate 6 guides the leading edge of the master 1 between the stage 13 and the clamper 14, and determines that the leading edge of the master 1 has reached the clamper 14 by the number of steps of a stepping motor (not shown). The clamper 14 is closed by an opening / closing device (not shown) to clamp the tip of the master 1 and the plate cylinder 7 resumes rotation at almost the same speed as the master conveyance speed, so that the master 1 thus made is wound. . When it is determined that the plate making is completed by the number of steps of a stepping motor (not shown), the cutter 5 is operated to cut the master 1, and the platen roller 2, the feed roller 4 and the like are stopped, and the cut master 1 is cut. The rear end is pulled out by the rotation of the plate cylinder 7 and the winding around the plate cylinder 7 is completed (S5).

  After winding the master 1 around the plate cylinder 7, the fan 19a of the air knife 19 is turned on, the temperature sensor 26 detects the temperature in the vicinity of the plate cylinder in the apparatus (S7), and the air volume control means according to the detected temperature. The air volume of the fan 19a of the air knife 19 is controlled (S8). Note that the fan air volume at this time is set such that high temperature ≧ normal temperature> low temperature. At high temperature, the fan 19a is rotated at a high speed and controlled to the maximum air volume, and at normal temperature, the fan 19a is rotated at a high speed to a medium speed to achieve the maximum air volume. It is controlled to a medium air volume, and at low temperatures, the fan drive is rotated at a low speed or a slow speed, or is turned OFF, and is controlled to a small air volume to a no air volume.

  Next, one sheet of printing paper 15 is fed from the paper feed tray 17 a by the paper feed device of the paper feed unit 39, and temporarily stops at the position of the registration roller 18. Then, the printing paper 15 is conveyed by the registration roller 18 between the plate cylinder 7 and the press roller 16 in alignment with the master 1 wound around the plate cylinder 7 (S9). At this time, when the printing paper 15 conveyed from the registration roller 18 between the plate cylinder 7 and the press roller 16 is detected by the paper sensor 24, the latch that holds the press roller 16 in a state of being separated from the plate cylinder 7. The press roller arm 16 a is rotated by a cam (not shown) that rotates in synchronization with the plate cylinder 7 by releasing the means, the press roller 16 is raised, and the press roller 16 is moved through the printing paper 15 and the master 1. 7 is pressed to press the printing paper 15 against the plate cylinder 7 to bring the master 1 wound around the plate cylinder 7 into close contact with the plate cylinder 7 (S10). When this printing is performed, ink is supplied by the ink roller 10, and the ink in the plate cylinder 7 oozes out from the opening of the plate cylinder 7 and the perforations of the master 1 and is transferred to the printing paper 15. An image is printed on the printing paper 5.

  Thereafter, when the printing paper 15 is conveyed along with the rotation of the plate cylinder 7, air is blown between the printing paper 15 and the plate cylinder 7 by the air knife 19, and the leading edge of the printing paper 15 is blown by the wind pressure. The tip of a peeling claw (not shown) is inserted between the printing paper 15 and the plate cylinder 7 so that the printing paper 15 is uniformly peeled from the plate cylinder 7. The printing paper 15 peeled off from the plate cylinder 7 is conveyed to the paper discharge tray 23 by the paper discharge conveying device 22 of the paper discharge unit 41 and discharged (S11). When the printing paper 15 is discharged and stacked on the paper discharge tray 23, the printing standby state is entered (S12).

  In this print standby state, when the number of prints is input from the operation / display unit 35 and a print start button (not shown) is pressed, it is determined that printing is started (S13), and the temperature sensor 26 detects the plate in the apparatus. The temperature in the vicinity of the trunk is detected again (S14), and the air volume of the fan 19a of the air knife 19 is controlled according to the detected temperature (S15). As described above, the air volume of the fan at this time is set such that high temperature ≧ normal temperature> low temperature. At high temperature, the fan 19a is rotated at a high speed and controlled to the maximum air volume, and at normal temperature, the fan 19a rotates at a high speed to a medium speed. The maximum air volume is controlled to the medium air volume, and at low temperatures, the fan drive is rotated at a low speed or a very low speed, or is turned OFF, and is controlled to a small air volume to no air volume.

  Next, the input printing sheets 15 are fed one by one from the sheet feeding tray 17a by the sheet feeding device 17 of the sheet feeding unit 39, and temporarily stop at the position of the registration roller 18 (S16). Then, the printing paper 15 is conveyed one by one by the registration roller 18 between the plate cylinder 7 and the press roller 16 in alignment with the master 1 wound around the plate cylinder 7 (S16). Thereafter, the printing paper 15 is pressed against the plate cylinder 7 via the master 1 by the press roller 16 in the same manner as the above-described plate-forming operation. Then, the ink in the plate cylinder 7 oozes out from the opening of the plate cylinder 7 and the perforations of the master 1 and is transferred to the printing paper 15 to print an image on the printing paper 15 (S17).

  When the printing paper 15 on which the image is printed is conveyed along with the rotation of the plate cylinder 7, air is blown between the printing paper 15 and the plate cylinder 7 by the air knife 19, and the leading edge of the printing paper 15 is caused by wind pressure. The tip of the peeling claw (not shown) is inserted between the printing paper 15 and the printing drum 7 so that the printing paper 15 is uniformly peeled from the printing drum 7. The printing paper 15 peeled off from the plate cylinder 7 is transported to the paper discharge tray 23 by the paper discharge transport device 22 of the paper discharge unit 41 and discharged (S18). After the printing paper 15 is discharged, it is determined whether or not the number of printed sheets has reached the set number. The operations in steps S14 to S18 are repeated until the set number of sheets is reached. 19 is stopped (S20), and the printing operation is terminated.

  Although the configuration and operation of the stencil printing apparatus according to the present invention have been described above, in such a stencil printing apparatus, the ink supplied to the inner peripheral surface of the plate cylinder 7 by the ink supply means is used to open the opening of the plate cylinder 7. In this system, the ink oozes out from the perforated portion of the master 1 and is transferred to the printing paper 15 for printing. 1), surplus ink begins to accumulate, travels along the master 1 after the release of printing pressure, moves gradually to the rear end of the master 1, and surpasses the rear end of the master 1, so that excess ink leaks out. “Leak leak” occurs.

  Here, the ink used in the stencil printing apparatus is composed of moisture, oil, and pigment, and the viscosity changes depending on the temperature. It is hard at low temperatures and soft at high temperatures. For this reason, the ink hardened at a low temperature loses its fluidity and tends to be left under the master 1 (between the plate cylinder 7 and the master 1) as surplus ink, and the above-described tail leakage tends to occur. On the other hand, the ink peeling performance is more difficult to peel as the ink is softer and easier to peel as the ink is harder. Therefore, it is difficult to peel off at a high temperature, and it is easy to peel off at a low temperature.

  In the stencil printing apparatus according to the present invention, in order to improve the peeling of the printing paper 15, an air knife 19 is provided in the vicinity of the plate cylinder 7, and the printing paper 15 is removed from the master 1 on the outer peripheral surface of the printing cylinder by the wind pressure of air. If the air volume of the fan 19a of the air knife 19 is set large in order to improve the releasability at room temperature to high temperature, and the air volume is controlled with a constant air volume regardless of the temperature, When the temperature is low, excess ink under the master 1 wound around the plate cylinder 7 is pushed to the rear end of the master 1 by wind pressure as shown in FIG. More likely to occur.

  Therefore, in the present invention, in consideration of the above-described reason, as described in the description of the control operation, the air volume of the fan 19a of the air knife 19 is controlled to vary depending on the temperature detected by the temperature sensor 26 during printing. The air volume of the fan 19a of the air knife 19 is controlled such that high temperature ≧ normal temperature> low temperature. That is, the air volume of the fan 19a of the air knife 19 is set to be large in order to improve the peelability at room temperature to high temperature, and the air volume of the fan 19a of the air knife 19 is weakened at low temperature or the fan 19a is turned off. Control to stop. In this way, when the air temperature is low, the air volume of the fan 19a of the air knife 19 is weakened or the fan is stopped, so that it is wound around the plate cylinder 7 after the printing pressure release position as shown in FIG. Even when there is excess ink under the master 1, the excess ink is not pushed to the rear end of the master due to the wind pressure of the air knife 19, and it is possible to prevent the ink from leaking out.

  In the stencil printing apparatus according to the present invention, as shown in FIG. 6, a plurality of fans 19-1, 19-2 and 19-3 of the air knife 19 are arranged in a direction orthogonal to the conveyance direction of the printing paper 15. In the case where a plurality of fans 19-1, 19-2, 19-3 are arranged in this way, the airflows of the plurality of fans 19-1, 19-2, 19-3 are respectively changed depending on the temperature. Control independently. When the air volumes of the plurality of fans 19-1, 19-2, 19-3 are independently controlled according to the temperature, the ink leakage at the center is the worst, so the plurality of fans 19-1, 19- 2, 19-3, the air volume of the fan 19-2 disposed at least in the center is controlled such that high temperature ≧ normal temperature> low temperature. More specifically, at a low temperature, the air volume of at least the fan 19-2 disposed in the center is weakened or the fan 19-2 is turned off to stop. As described above, when three or more fans 19-1, 19-2, 19-3 are used for the air knife 19, even if control is performed to stop only the central fan 19-2, the tail leaks. It is effective enough to prevent the occurrence of

  In the above-described control of the fan of the air knife 19, in this embodiment, the low temperature range is controlled to be 17 ° C. or lower, the normal temperature is 17 to 26 ° C., and the high temperature is 26 ° C. or higher. However, the setting of the temperature range is not limited to this, and is changed according to the characteristics of the ink used.

  As described above, in the present invention, the air volume control means for controlling the air volume of the air knife fan is provided, the air volume of the air knife fan is varied depending on the temperature, and the fan is suitable for each temperature range of high temperature, normal temperature, and low temperature. By setting the air volume of the ink, it is possible to prevent the trailing edge of the ink from getting worse while maintaining the peelability of the printing paper. Therefore, by utilizing the present invention, it is possible to contribute to improvement in performance of the stencil printing apparatus and improvement in printing quality.

1 is a schematic configuration diagram of a main part of a stencil printing apparatus showing an embodiment of the present invention. It is a block diagram which shows an example of the control system of the stencil printing apparatus of the structure shown in FIG. It is a flowchart which shows an example of control operation of a stencil printing apparatus. It is explanatory drawing for demonstrating the amount of leaks of the excess ink when the wind pressure of an air knife is strong at the time of low temperature. It is explanatory drawing for demonstrating the amount of leaks of the excess ink when the wind pressure of an air knife is weak or stops at the time of low temperature. It is a schematic perspective view which shows an example of the air knife provided with the several fan which concerns on this invention.

Explanation of symbols

1: Master 1a: Master roll 1b: Master roll core 2: Platen roller 3: Thermal head 4: Feed roller 5: Cutter 6: Guide plate 7: Plate cylinder 8: Ink pipe 9: Drive motor 10: Ink roller 10a: Ink Roller shaft 11: Doctor roll 12: Ink reservoir 13: Stage 14: Clamper 15: Printing paper 16: Press roller (pressing pressure member)
17: Paper feeding device 17a: Paper feeding tray 17b: Paper feeding roller 18: Registration roller 19: Air knife 19a: Fan 19-1, 19-2, 19-3: Fan 20: Plate removal device 21: Disposal unit 22: Waste Paper transport device 23: paper discharge tray 24: paper sensor 25: paper discharge sensor 26: temperature sensor 30: main control unit 36: image reading unit 37: plate making unit 38: printing unit 39: paper feeding unit (paper feeding unit)
40: Discharge part 41: Paper discharge part 42: Plate cylinder sensor 43: Paper size sensor

Claims (7)

A rotatable plate cylinder having an opening through which ink oozes out, an ink supply means for supplying ink to the inner peripheral surface of the plate cylinder, and a pressing pressure provided so as to be able to contact with and separate from the outer peripheral surface of the plate cylinder And a sheet feeding means for feeding printing paper to a transfer portion between the member and the plate cylinder and the pressing member, and after the master made on the outer periphery of the plate cylinder is wound, The printing paper fed to the transfer unit by paper means is pressed against the master on the plate cylinder by the pressing member, so that the ink exuded from the opening of the plate cylinder and the master perforation unit is applied to the printing paper. In a stencil printing machine that performs printing by transferring,
Equipped with an air knife that peels the printing paper on which ink has been transferred from the plate cylinder with air pressure, and an air volume control means that controls the air volume of the air knife fan. The air volume of the air knife fan can be varied according to the temperature during printing. A stencil printing apparatus characterized by being made to perform. In the stencil printing apparatus according to claim 1,
The air volume of the fan of the air knife is controlled to be high temperature ≧ normal temperature> low temperature. In the stencil printing apparatus according to claim 2,
A stencil printing apparatus characterized in that the air volume of an air knife fan is weakened or the fan is stopped at a low temperature. In the stencil printing apparatus according to claim 1,
A stencil printing apparatus comprising a plurality of fans of the air knife in a direction orthogonal to a conveying direction of the printing paper, and independently controlling air volumes of the plurality of fans according to temperature. In the stencil printing apparatus according to claim 4,
A stencil printing apparatus, wherein the air volume of a fan arranged at least in the center of the plurality of fans of the air knife is controlled such that high temperature ≧ normal temperature> low temperature. In the stencil printing apparatus according to claim 5,
A stencil printing apparatus characterized in that, at a low temperature, the air volume of at least the fan arranged at the center is weakened or the fan is stopped. In the stencil printing apparatus according to any one of claims 2, 3, 5, and 6,
The stencil printing apparatus is controlled at a low temperature range of 17 ° C. or lower, a normal temperature of 17 to 26 ° C., and a high temperature of 26 ° C. or higher.

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