JP5239020B2 - Stencil printing machine - Google Patents

Description

  The present invention relates to a stencil printing apparatus having a refeeding unit and capable of performing one-step duplex printing.

  Conventionally, digital thermal stencil printing is known as a simple printing method. This is because a thermal head having a plurality of fine heating elements is brought into contact with a master obtained by bonding a thermoplastic resin film and a porous support, and the master is placed on a platen roller or the like while energizing the heating elements in a pulsed manner. After the punched image based on the image information is hot-melt perforated and engraved on the thermoplastic resin film of the master by conveying with a conveying means, the perforated master is wound around a porous cylindrical plate cylinder and pressed. By pressing the paper against the outer peripheral surface of the plate cylinder by pressing means such as a roller, the ink supplied to the inner peripheral surface of the plate cylinder is oozed out from the plate cylinder opening portion and the master punching portion, and this ink is transferred to the paper A printed image is obtained on a sheet.

  In the stencil printing described above, duplex printing has recently been frequently performed in which printing is performed on both sides of a sheet for the purpose of reducing the amount of paper consumed and the storage space for documents. As an example of this, a divided pre-printed master in which the first plate-making image and the second plate-making image are arranged in two directions in the direction of rotation of the plate cylinder is used. After the plate-making image is printed, this paper is guided to the auxiliary tray, and after one plate-making image is printed on the surface of the second sheet fed from the paper feeding unit, this paper is guided to the auxiliary tray, and the auxiliary tray The first sheet is re-feeded from the tray, the other plate-making image is printed on this back surface, this sheet is discharged to the sheet discharge tray, and this operation is continuously performed to obtain a double-sided printed matter in one step. A stencil printing apparatus is disclosed in, for example, “Patent Document 1”.

Japanese Patent No. 4037277

  In the above-described stencil printing apparatus, printing on one side is sent to the paper re-feeding unit, and the paper is fed again in a state of being reversed from the re-feeding unit toward the printing unit, thereby printing on the other side. At that time, the paper is temporarily stopped by the paper re-feeding means, the registration is adjusted and the skew is corrected, and then the paper is fed again toward the printing unit. The refeeding means has a conveyor-like refeeding conveyance member as means for conveying the paper.

  The above-described refeed conveyance member has a driving roller, a driven roller, an endless belt stretched over the driving roller, a suction fan for sucking paper onto the endless belt, and the like. Since the driving force from the driving force generating means such as a motor is transmitted via the force transmitting means, it is inevitable that backlash between the gears or play in the D-type retaining ring that fixes the gear and the shaft occurs. As a result, there is a slight time lag between the start of operation of the driving force generating means and the start of movement of the endless belt. If both the direction in which the backlash increases and the direction in which the backlash occurs during the printing operation, the time lag described above will change, and this causes variations in the re-feed transport timing and transport amount, resulting in paper registration alignment. There is a problem that the position varies and the re-feed resist performance deteriorates.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a stencil printing apparatus that solves the above-described problems and can improve the refeed resist performance during double-sided printing.

The invention according to claim 1 is a printing unit having a plate cylinder and a press roller that presses the sheet against the plate cylinder, a paper discharge unit that discharges a sheet printed in the printing unit, and one of the printing unit A paper re-feeding means for re-feeding the paper toward the printing unit in a manner along the peripheral surface of the press roller after temporarily storing the paper on which the printed image is formed on the surface, and the paper that has passed through the printing unit And a displaceable switching member that selectively occupies the first position for guiding the sheet to the paper discharge section or the second position for guiding the sheet re-feeding means, and a surface image on one side of the sheet After the front surface printing process for printing the paper, the paper is sent to the refeeding means, and the paper is refeeded from the refeeding means to the printing unit to print the back image on the other side of the paper 1-sided double-sided printing is possible, and the refeeding is performed. The stage has an auxiliary tray for temporarily storing paper on which a printed image is formed on one side, and a refeed conveyance member for conveying the paper stored on the auxiliary tray toward the printing unit. In the stencil printing apparatus, the re-feed conveyance member includes a conveyance belt that conveys a sheet and a drive motor that drives the conveyance belt to run, and pre-rotates the drive motor before conveyance of the sheet by the conveyance belt , The rotational speed of the drive motor by this preliminary rotation is lower than that during paper conveyance .

  According to a second aspect of the present invention, in the stencil printing apparatus according to the first aspect, the preliminary rotation of the drive motor is performed before the paper is placed on the transport belt.

  According to a third aspect of the present invention, in the stencil printing apparatus according to the first aspect of the present invention, a sheet guided by pinching the leading edge of the sheet fed to the refeeding means by the switching member occupying the second position. And a pre-rotation of the drive motor is performed before the sheet nipped by the sheet clamper is released.

  According to the present invention, there is no time lag between the timing at which the drive motor starts to rotate and the timing at which the conveyor belt starts to travel, and the conveyor belt starts to travel at the same time as the drive motor starts to rotate. Since there is no variation in the refeed conveyance timing and the sheet conveyance amount, it is possible to prevent the deterioration of the refeed resist performance and perform a good refeed.

  FIG. 1 shows a stencil printing apparatus adopting an embodiment of the present invention. Since this stencil printing apparatus has a configuration related to the printing apparatus disclosed in Japanese Patent No. 4037277, description of each part is omitted as much as possible.

  In FIG. 1, a stencil printing apparatus 1 includes a printing unit 2, a plate making unit 3, a paper feeding unit 4, a plate discharging unit 5, a paper discharging unit 6, an image reading unit 7, a refeed unit 9 having an auxiliary tray 8, and a switching member 10. Etc.

  The printing unit 2 disposed almost at the center of the apparatus main body 42 includes a plate cylinder 11 and a press roller 12. The plate cylinder 11 is rotatably supported by the apparatus main body 42 and is driven to rotate by a plate cylinder driving means (not shown). The plate cylinder 11 has an openable / closable clamper 13 on the outer peripheral surface thereof, and the divided master 14 made by the plate making unit 3 is wound around the outer peripheral surface of the plate cylinder 11 at the time of duplex printing. The division master 14 is formed with a first plate making image corresponding to the front surface image and a second plate making image corresponding to the back surface image, and an unmade portion is formed between the plate making images. The division master 14 is wound on the plate cylinder 11 so that the first plate-making image corresponds to the front surface region shown in FIG. 1, the second plate-making image corresponds to the same back surface region, and the non-plate making portion corresponds to the intermediate region. The

  A press roller 12 is disposed below the plate cylinder 11. Both ends of the press roller 12 made of an elastic material having water repellency such as fluororesin are rotatably supported by an arm member (not shown). The arm member (not shown) is swingably supported by a swing means (not shown). Yes. The press roller 12 selectively occupies the separation position shown in FIG. 1 where the circumferential surface is separated from the plate cylinder 11 and the pressure contact position where the circumferential surface is pressed against the divided master 14 on the plate cylinder 11. In the vicinity of the peripheral surface of the press roller 12, a cleaning roller 16 that is driven to rotate by a driving unit (not shown) and that contacts the peripheral surface of the press roller 12 to perform cleaning is disposed.

  In the vicinity of the right side of the press roller 12, a refeed guide member 17 is provided for transporting the surface-printed paper P sent from the refeed unit 9 along the peripheral surface of the press roller 12. A re-feeding registration roller 18 is disposed below the press roller 12 and feeds the paper P stored on the auxiliary tray 8 in contact with the peripheral surface of the press roller 12. A refeed conveyance unit 19 as a refeed conveyance member having an auxiliary tray 8 on the upper surface is disposed on the lower left side of the press roller 12, and a refeed positioning member 20 is provided integrally therewith. ing. A sheet receiving plate 21 that is movable along the upper surface of the auxiliary tray 8 is disposed above the refeed conveyance unit 19. The auxiliary tray 8, the refeed guide member 17, the refeed registration roller 18, the refeed positioning member 20, the refeed conveyance unit 19, and the sheet receiving plate 21 constitute a refeed unit 9.

  As shown in FIG. 2, the refeed conveyance unit 19 includes a driving roller 22, a driven roller 23, a conveyance belt 24 that is an endless belt, a suction fan 25, and the like. The conveying belt 24 stretched between the rollers 22 and 23 is driven by a driving motor 30 via a gear 26, an idle gear 27, a pinion gear 28 and a timing belt 29 attached to a support shaft 22a of the driving roller 22. 1 is driven to rotate in the direction indicated by the arrow in FIG.

  On the left side of the contact position between the plate cylinder 11 and the press roller 12, the switching member 10 is disposed on the conveyance path of the paper P. The switching member 10 is rotatably supported by the apparatus main body 42 at the downstream end portion in the paper conveyance direction, and is moved by a moving means (not shown), and is indicated by a first position indicated by a solid line and a two-dot chain line in FIG. Selectively occupying the second position. The paper P that has passed between the plate cylinder 11 and the press roller 12 is guided to the paper discharge unit 6 when the switching member 10 occupies the first position, and the switching member 10 occupies the second position. Is guided to the auxiliary tray 8.

  A plate making unit 3 is disposed on the upper right side of the printing unit 2. The plate making unit 3 includes a master holding member 32 that holds a master roll obtained by winding a master 31 in a roll shape, a platen roller 33, a thermal head 34, a master cutting unit 35, a master stock unit 36, a tension roller pair 37, and a reverse roller pair. 38 and the like, and the divided master 14 is created in the plate making unit 3 at the time of duplex printing.

  A sheet feeding unit 4 is disposed below the plate making unit 3. The paper feed unit 4 includes a paper feed tray 39, a paper feed roller 40, a separation roller 41, a separation pad 43, a registration roller pair 15, and the like. A paper feed tray 39 capable of stacking a large number of sheets P on the upper surface is supported by the apparatus main body 42 so as to be movable up and down, and is moved up and down by elevating means (not shown). A pair of side fences 45 that align the paper P in the width direction are disposed on the upper surface of the paper feed tray 39.

  The plate discharging unit 5 disposed on the upper left side of the printing unit 2 has a known configuration including an upper plate discharging member 46, a lower plate discharging member 47, a plate discharging box 48, a compression plate 49, and the like. The drum 11 is peeled off from the outer peripheral surface of the cylinder 11 and discarded in the discharge box 48.

  A paper discharge unit 6 is disposed below the plate discharge unit 5. The paper discharge unit 6 includes a peeling claw 50, a paper discharge transport unit 51, a paper discharge tray 52, and the like. The front end of the peeling claw 50 is provided so as to be close to and away from the outer peripheral surface of the plate cylinder 11 by a swinging means (not shown), and the sheet P is formed on the outer peripheral surface of the plate cylinder 11 when occupied. To peel off. The paper discharge conveyance unit 51 includes a driving roller, a driven roller, an endless belt, a suction fan, and the like, and conveys the printed paper P on the upper surface of the endless belt in the arrow direction of FIG. The paper discharge tray 52 has one end fence and a pair of side fences, and the printed paper P is stacked on the upper surface thereof.

  An image reading unit 7 is disposed on the upper part of the apparatus main body. The image reading unit 7 is scanned with a contact glass 53, a pressure plate 54 provided so as to be able to contact with and separate from the contact glass 53, reflection mirrors 55, 56, 57, 58 and a fluorescent lamp 59 that scan and read a document image. A lens 60 for focusing the image, an image sensor 61 for processing the focused image, and the like are included.

  In the stencil printing apparatus 1 described above, when a document is set in the image reading unit 7 and a plate making start key (not shown) is pressed, the plate making unit 3 is operated after the plate discharging unit 5 is operated and the plate discharging operation is performed. A plate-making operation is performed, and a plate-making master is wound around the plate cylinder 11 to enter a single-sided printing standby state. Thereafter, when a print start key (not shown) is pressed after the number of printed sheets is set, the sheet P is continuously fed from the sheet feeding unit 4 and a one-sided printing operation is performed. When the set number of printed sheets is reached, the single-sided printing operation is completed, and the stencil printing apparatus 1 enters the single-sided printing standby state again.

  In addition, after the original is set in the image reading unit 7 and the duplex printing mode is set, a plate making start key (not shown) is pressed, so that the plate making unit 5 is activated and the plate making operation is performed. Then, a plate making operation is performed, and the divided master 14 is wound around the plate cylinder 11 to enter a duplex printing standby state. Thereafter, when a print start key (not shown) is pressed after the number of printed sheets is set, the sheet P is continuously fed from the sheet feeding unit 4 and duplex printing is performed. Hereinafter, the duplex printing operation will be described.

  When the plate cylinder 11 is rotated to a predetermined angle and its surface area occupies a predetermined position corresponding to the press roller 12, the press roller 12 occupies the press contact position, so that the paper P becomes the first of the divided masters 14 on the plate cylinder 11. The surface image is transferred to one surface of the plate-making image. The paper P that has been printed on the front surface is peeled off from the outer peripheral surface of the plate cylinder 11 by the tip of the switching member 10 occupying the second position, and is sent to the refeed conveyance unit 19. At this time, the front end of the paper P is received by the paper receiving plate 21 and is placed on the auxiliary tray 8 from the rear end side. The paper P on the auxiliary tray 8 is transported in the direction of the arrow in FIG. 1 by the paper refeeding transport unit 19, and is temporarily stopped with its leading end abutting against the paper refeeding positioning member 20.

  The plate cylinder 11 continues to rotate while the first sheet P is guided onto the auxiliary tray 8, and the second sheet is fed from the sheet feeding unit 4 at the same timing as the first sheet P. P is fed. Similarly to the first sheet P, the fed second sheet P is re-transferred by the switching member 10 occupying the second position after the surface image is transferred to one surface thereof by the press roller 12. It is sent to the paper feeding / conveying unit 19. After the second sheet P is fed from the sheet feeding unit 4, the re-feeding registration roller 18 is operated at a slightly earlier timing than the back surface area of the plate cylinder 11 reaches the position corresponding to the press roller 12. Then, the first sheet P stored on the auxiliary tray 8 is pressed against the peripheral surface of the press roller 12. The first sheet P pressed against the peripheral surface of the press roller 12 is conveyed toward the contact portion with the plate cylinder 11 by the rotational force of the press roller 12 that is pressed against the plate cylinder 11 and rotated. The back image is transferred to the other surface by being pressed against the second plate-making image of the division master 14.

  The first sheet P, which has been transferred to the back side and has been printed on both sides, is guided to the paper discharge unit 6 by the switching member 10 occupying the first position. It peels from the outer peripheral surface. The peeled printed paper P is sent to the paper discharge transport unit 51, and then transported and discharged and stacked on the paper discharge tray 52. Thereafter, the above operation is repeated until the set number of printed sheets is consumed. When the set number of double-sided printing operations are completed, the operation of each part is stopped and the stencil printing apparatus 1 enters the double-sided printing standby state again.

  In the above-described double-sided printing operation, the sheet P having the surface image transferred on one side is sent to the refeed conveyance unit 19 by the switching member 10 and is conveyed in the direction of the arrow in FIG. Although it is temporarily stopped in a state of being in contact with the paper positioning member 20, as described in the section “Problems to be solved by the invention”, backlash and gear between the gears constituting the refeed conveyance unit 19 are described. Due to the play of the D-type retaining ring that fixes the shaft and the shaft, a time lag occurs from the start of operation of the drive motor 30 to the start of movement of the conveyor belt 24, and the change in the time lag causes the re-feeding resist performance capability to be increased. There is a problem that it gets worse.

  In the present invention, in order to solve the above-described problems, the drive motor 30 is slightly rotated in the same direction as the sheet transport direction at a timing before the original rotation start timing (this is referred to as preliminary rotation). A configuration is adopted in which the play is eliminated in advance. With this configuration, no time lag occurs between the timing at which the drive motor 30 starts to rotate and the timing at which the conveyor belt 24 starts to travel, and the conveyor belt 24 starts to travel at the same time as the drive motor 30 starts to rotate. Accordingly, since there is no variation in the refeed conveyance timing and the sheet conveyance amount up to the refeed positioning member 20, it is possible to prevent the deterioration of the refeed resist performance and perform a good refeed. This pre-rotation operation is performed after the paper P on the auxiliary tray 8 is re-fed to the printing unit 2 by the re-feeding registration roller 18 and the operation of the drive motor 30 is stopped until the next drive motor 30 is activated. In other words, it may be completed before the next sheet P is placed on the conveyor belt 24. FIG. 4 shows a timing chart of this preliminary rotation operation.

  The rotational speed of the drive motor 30 by the above-described preliminary rotation is set to be lower than that at the time of paper conveyance (in the case of a stepping motor, the self-starting area or the like). FIG. 5 shows a comparison between the rotation speed during the preliminary rotation and the rotation speed during normal printing. This is because if it is rotated at a high speed, it must be stopped suddenly due to time constraints in the subsequent printing operation, and play will occur again. With this configuration, it is possible to prevent backlash and to continue good refeed resist performance.

  In the above-described embodiment, the paper receiving plate 21 does not have the paper clamper that sandwiches the leading end of the paper P as the paper refeeding unit 9, but the paper clamper 63 shown in FIG. The sheet receiving plate 62 having the above may be applied to the present invention. The paper clamper 63 is a member that clamps the leading end of the single-side printed paper P guided by the switching member 10, and the operation thereof is the same as that of the paper clamper 168e disclosed in Japanese Patent No. 4037277. In this configuration, after the paper clamper 63 clamps the leading edge of the paper P on which single-sided printing is performed, the paper P is clamped by the paper clamper 63 until the paper receiving plate 62 reaches the open position from the paper P holding position. The above-mentioned preliminary rotation is performed before the is opened. A timing chart of this preliminary rotation operation is shown in FIG. As a result, there is no time lag between the timing at which the drive motor 30 starts to rotate and the timing at which the conveyor belt 24 starts to travel, and the conveyor belt 24 starts to travel at the same time as the drive motor 30 starts to rotate. It is possible to prevent the paper re-feeding resist performance from deteriorating and to perform good paper re-feeding.

1 is a schematic front view of a stencil printing apparatus capable of double-sided printing employing an embodiment of the present invention. It is the schematic of the conveyance belt and drive motor which are used for one Embodiment of this invention. It is the schematic of the paper receiving plate and paper clamper used for other embodiment of this invention. It is a timing chart explaining preliminary rotation operation in one embodiment of the present invention. It is a timing chart explaining the speed of preliminary rotation operation in one embodiment of the present invention. It is a timing chart explaining preliminary rotation operation in other embodiments of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Stencil printing apparatus 2 Printing part 6 Paper discharge part 8 Auxiliary tray 9 Refeeding means 10 Switching member 11 Plate cylinder 12 Press roller 19 Refeeding conveyance member (refeeding conveyance unit)
24 Conveyor belt 30 Drive motor 63 Paper clamper P Paper

Claims (3)

A printing unit having a plate cylinder and a press roller that presses the sheet against the plate cylinder, a paper discharge unit that discharges the sheet printed by the printing unit, and a printed image is formed on one surface of the printing unit. A sheet re-feeding unit that re-feeds the printed sheet toward the printing unit in a manner along the peripheral surface of the press roller after temporarily storing the sheet, and guides the sheet that has passed through the printing unit to the paper discharge unit. A displaceable switching member that selectively occupies the first state or the second state guided to the re-feeding means, and performing a surface printing step of printing a surface image on one side of the paper 1 step of performing a back side printing step of feeding the paper to the refeeding unit afterwards, refeeding the paper from the refeeding unit to the printing unit, and printing a backside image on the other side of the paper Double-sided printing is possible, and the refeed unit prints on one side In the stencil printing machine having an auxiliary tray for temporarily 貯容 the sheet image is formed, and a refeeding member for transporting said is 貯容 on the auxiliary tray sheet to the printing unit,
The refeeding member and a drive motor for driving the conveyor belt and the conveyor belt for conveying paper, is pre-rotated the drive motor before conveyance of the sheet by the conveyance belt, wherein by this preliminary rotation A stencil printing apparatus characterized in that the rotational speed of the drive motor is lower than that during paper conveyance . In the stencil printing apparatus according to claim 1,
The stencil printing apparatus, wherein the drive motor is preliminarily rotated before the paper is placed on the transport belt. In the stencil printing apparatus according to claim 1,
A paper clamper that pinches and guides the leading edge of the paper fed to the refeeding means by the switching member that has occupied the second position, and the preliminary rotation of the drive motor is pinched by the paper clamper A stencil printing apparatus, which is performed before a sheet is released.

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