JP2016087950A - Double-side stencil printing device and ink adjustment method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To permit stable paper passing performance and satisfactory maintenance performance by preventing staining of both-side paper re-feeding part due to ink transferred to a printing sheet surface when performing ink adjustment by using a printing sheet for both-side printing by means of a both-side stencil printing device.SOLUTION: When performing usual both-side printing, a printing sheet P loaded on a paper feeding tray 67 is fed to a printing part 2 by one sheet for one rotation of a plate cylinder 12, a surface plate-making image is printed on a sheet surface, thereafter, is fed to the printing part 2 through a re-paper feeding part 9, a back surface plate-making image is printed on the sheet back surface and, thereafter, is discharged to a paper discharging tray 86. When performing trial printing for ink adjustment, the printing sheet P is fed to the printing part 2 by one sheet for one rotation of the plate cylinder 12, the surface plate-making image is printed on the sheet surface, thereafter, is discharged to the paper discharging tray 86, the printing sheet P is fed to the printing part 2 by one sheet for the subsequent one rotation of the plate cylinder 12 and the back surface plate-making image is printed on the sheet surface and, thereafter, is discharged to the paper discharge tray 86.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a double-sided stencil printing apparatus and an ink adjustment method thereof.

  One of the printing devices is a stencil printing device. The stencil printing apparatus wraps a master in which holes corresponding to a document image are formed by a punching process corresponding to a plate making process around a printing drum having an ink transmission structure, and ink from an ink supply mechanism provided in the printing drum. The image is printed by leaching the ink and transferring the ink to the printing paper pressed against the printing drum.

  Moreover, as a stencil printing device, in addition to single-sided printing (also referred to as full-surface printing) in which printing is performed only on one side of printing paper, in recent years for the purpose of reducing printing paper consumption and document storage space, There is a double-sided stencil printing apparatus capable of double-sided printing that performs printing on both sides of printing paper (Patent Document 1).

  In this double-sided stencil printing apparatus, a master in which a first plate-making image and a second plate-making image are divided and made in two sides along the rotation direction of the printing drum is wound around the printing drum, and the first plate-making image or Printing corresponding to one of the second plate-making images (front surface printing) is performed in the printing unit, and the printing paper on which the surface printing has been performed is re-fed to the printing unit by the double-sided paper re-feeding unit. Print on the back of the printing paper.

  When performing single-sided printing in this duplex printing apparatus, a master on which one plate-making image is made is wound around the printing drum along the rotation direction of the printing drum, printing is performed in the printing unit, and printed printing paper is discharged. Make paper. The maximum size of each plate-making image in double-sided printing is ½ of the size of the maximum plate-making image in single-sided printing. Further, the maximum size of printing paper used for double-sided printing (hereinafter, printing paper for double-sided printing) is ½ of the maximum size of printing paper used for single-sided printing (hereinafter referred to as printing paper for single-sided printing). That is, when the maximum size of the printing paper in single-sided printing is A3, the maximum size of the printing paper in double-sided printing is A4.

  In stencil printing apparatuses, emulsion ink is often used as printing ink. Emulsion ink consists of an oil phase component containing carbon, an aqueous phase component and a solvent depending on the ink. When left in contact with air, the aqueous phase component and the solvent component gradually evaporate, and the oil in the ink The relative proportion of phase components increases. When the oil phase component ratio increases, the viscosity of the ink decreases, and the so-called relaxed state is obtained.

  For this reason, in the stencil printing device, if printing is not performed for a long time after the final job is printed (the device stop period is long), the ink in the printing drum is loosened. Since the amount of ink permeated from the formed holes increases, excessive transfer of ink to the printing paper occurs.

  Therefore, when printing after a certain amount of time has passed since the last printing (previous printing) in the stencil printing device, discard printing as ink adjustment is performed before normal printing to refresh the ink. (Patent Document 2). By this ink adjustment, it is possible to prevent the ink from being excessively transferred during normal printing by transferring the loose ink to the printing paper.

  However, in the case of a double-sided stencil printing apparatus, if printing is performed on double-sided printing paper in order to refresh ink on both the first plate-making image surface and the second plate-making image surface, The ink that has been excessively transferred to the surface contaminates the reversing roller of the double-sided paper refeed section and the paper conveyance path. As a result, separate cleaning is required to prevent the printing paper from being smeared with ink during regular printing. In addition, stable paper passing performance cannot be ensured, and the sticking force between the printing drum and the printing paper is increased, so that the printing paper is not peeled off from the printing drum, resulting in paper conveyance failure.

  The present invention has been made to solve such a problem, and its purpose is transferred to the surface of a printing paper when performing ink adjustment using a printing paper for double-sided printing in a double-sided stencil printing apparatus. In other words, the double-sided paper refeeding section is prevented from being stained by the ink, and stable paper feeding performance and good maintainability are realized.

  The double-sided stencil printing apparatus according to the present invention includes a plate-making unit for making a master, a printing drum on which a double-side plate-making master on which a first plate-making image and a second plate-making image are made side by side by the plate-making unit is wound, A printing unit having pressing means that can be moved toward and away from the printing drum, a paper feeding unit that feeds printing paper to the printing unit, and a printed printing sheet that has been printed in a predetermined manner by the printing unit. And a paper sheet for duplex printing on which one of the first plate-making image or the second plate-making image is printed on the surface by the printing unit when the predetermined printing is duplex printing. A re-feeding unit that feeds the other one of the first plate-making image or the second plate-making image onto the back side, and feeding the printing sheet for double-sided printing to the printing drum One sheet for each rotation of the first One of the plate image and the second plate-making image is printed and discharged by the paper discharge unit, and the other of the first plate-making image or the second plate-making image is printed and the paper discharge unit 2 is a double-sided stencil printing apparatus having a single-sided ink adjustment mode for performing a paper discharge operation.

  According to the present invention, when ink adjustment is performed using a printing paper for double-sided printing in a double-sided stencil printing apparatus, the double-sided paper refeeding portion is prevented from being soiled by ink transferred to the surface of the printing paper, so that stable printing is possible. Paper performance and good maintainability can be realized.

1 is a schematic front view of a double-sided stencil printing apparatus according to an embodiment of the present invention. It is a figure for demonstrating the printing paper and plate-making master in double-sided printing and single-sided printing in the double-sided stencil printing apparatus which concerns on embodiment of this invention. It is the schematic of the operation panel in the double-sided stencil printing apparatus which concerns on embodiment of this invention. It is a block diagram of a control system of a double-sided stencil printing apparatus according to an embodiment of the present invention. It is a flowchart of the plate-making printing operation | movement of the double-sided stencil printing apparatus which concerns on embodiment of this invention. It is a figure for demonstrating the printing pressure at the time of the plate-making printing operation of the double-sided stencil printing apparatus which concerns on embodiment of this invention, and plate-making area | region.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
<Schematic configuration of double-sided stencil printing machine>
FIG. 1 is a schematic front view of a double-sided stencil printing apparatus according to an embodiment of the present invention.

  The double-sided 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, an auxiliary tray 8, a refeeding unit 9, a switching member 10, and the like. Have.

  The printing unit 2 is disposed substantially at the center of the printing apparatus main body 11 and includes a plate cylinder 12 as a printing drum and a press roller 13 as a pressing unit. The plate cylinder 12 is detachably and rotatably supported by the printing apparatus main body 11, and is rotated in the direction of the arrow (clockwise) in the figure by a printing drum driving means 121 (see FIG. 4) including a main motor composed of, for example, a DC motor. Driven.

  A clamper 19 is provided on the outer peripheral surface of the plate cylinder 12 to hold the leading end of a master that has been perforated by the plate making unit 3. In the present embodiment, a split master-making master (double-side master making master) is wound around double-sided printing, and a master-made master (single-side master making master) is wound around single-sided printing (illustrated split master-making master 65). A plate-making master capable of single-side printing on A3-size printing paper can be wound around the plate cylinder 12.

  The plate cylinder 12 has a printable image forming area (hereinafter referred to as “opening”) in which a large number of ink-permeable holes are formed and a non-image forming area (hereinafter referred to as “non-image forming area”) in which the clamper 19 is disposed. Are formed along the rotational direction of the plate cylinder 12. The image forming area includes a first image area 12a (hereinafter referred to as “front surface area 12a”), an intermediate area 12s, and a second image area 12b (hereinafter referred to as “back surface area 12b”) in the plate cylinder 12 in the drawing. )).

  An ink supply means 15 is provided inside the plate cylinder 12. The ink supply means 15 includes a support shaft 14 that also serves as an ink supply pipe, an ink roller 16, a doctor roller 17, and the like. A plurality of small holes are formed in the support shaft 14, and the ink supplied from the support shaft 14 is collected in a space formed in the vicinity of the ink roller 16 and the doctor roller 17. It is formed.

  A press roller 13 is provided below the plate cylinder 12 so as to be able to contact with and separate from the outer peripheral surface of the plate cylinder 12. Both ends of the press roller 13 are rotatably supported by an arm member, and the arm member is swingably supported by swinging means. The press roller 13 selectively occupies the illustrated separation position in which the circumferential surface is separated from the plate cylinder 12 and the press-contact position in which the circumferential surface is in pressure contact with the master made on the plate cylinder 12.

  In the vicinity of the peripheral surface of the press roller 13, a cleaning roller 26 that performs cleaning by contacting the peripheral surface of the press roller 13 is provided. The cleaning roller 26 is driven to rotate by driving means.

  In the vicinity of the right side of the press roller 13, the front side and the back side of the printing paper P are reversed by transporting the printing paper P having been printed on the front surface sent from the refeed unit 9 along the peripheral surface of the press roller 13. A refeed guide member 22 for refeeding is provided.

  Below the press roller 13, there is provided a re-feeding registration roller 23 that feeds the printing paper P printed on the surface stored on the auxiliary tray 8 in contact with the peripheral surface of the press roller 13. A refeed conveyance unit 25 having an auxiliary tray 8 on the upper surface is provided on the lower left side of the press roller 13, and a refeed positioning member 24 is provided integrally therewith.

  On the left side of the contact position between the plate cylinder 12 and the press roller 13 and on the conveyance path of the printing paper P, a switching member 10 is provided. The switching member 10 has a downstream end portion in the printing paper transport direction Xa that is rotatably supported by the printing apparatus main body 11 and is moved by the moving means. The first position indicated by a solid line in FIG. Selectively occupying the second position shown.

  The printing paper P that has passed between the plate cylinder 12 and the press roller 13 is guided to the paper discharge unit 6 when the switching member 10 occupies the first position, and the switching member 10 moves to the second position. When occupied, it is guided to the auxiliary tray 8 by the guide plate 56.

  These auxiliary tray 8, refeed guide member 22, refeed resist roller 23, refeed positioning member 24, refeed transport unit 25, and guide plate 56 constitute a refeed section 9.

  A plate making unit 3 is provided on the upper right side of the printing unit 2. The plate making unit 3 includes a master holding member 57 that holds a master roll obtained by winding a master 64 in a roll shape, a platen roller 58, a thermal head 59, a master cutting means 60, a master stock unit 61, a tension roller pair 62, and a reverse roller pair. 63 and the like.

  Here, with reference to FIG. 2, the printing paper and the master-making master in double-sided printing and single-sided printing in the double-sided stencil printing apparatus 1 are described. FIG. 2A relates to double-sided printing, and FIG. 2B relates to single-sided printing.

  The plate making unit 3 performs plate making on the master 64, and at the time of double-sided printing, as shown in FIG. 2A, along the rotation direction of the plate cylinder 12, the first plate making image 65a for front side printing and the first side plate for back side printing. A divided master-making master 65 having two master-making images 65b is created. Further, at the time of single-sided printing, as shown in FIG. 2B, a third platemaking image 66a having an image amount area corresponding to two sides of the front platemaking image 65a and the backside platemaking image 65b along the rotation direction of the plate cylinder 12 is provided. The master-making master 66 is created.

  The first plate-making image 65a is formed at a position corresponding to the surface region 12a shown in FIG. 1 when the divided plate-making master 65 is wound around the outer peripheral surface of the plate cylinder 12, and the second plate-making image 65b is It is formed at a position corresponding to the back surface region 12b. Further, the first plate-making image 65a and the second plate-making image 65b print images on the front surface Pa and the back surface Pb of double-sided printing paper (for example, A4 size).

  The third plate-making image 66a is formed at positions corresponding to the front surface region 12a, the intermediate region 12s, and the back surface region 12b shown in FIG. 1 when the pre-printed master 66 is wound around the outer peripheral surface of the plate cylinder 12. The In addition, an image is printed on the surface Pc of the printing paper for single-sided printing (for example, A3 size) by the third plate-making image 66a.

  Returning to the description of FIG. A sheet feeding unit 4 is provided below the plate making unit 3. The paper feed unit 4 is a well-known one having a paper feed tray 67 on which the print paper P is stacked, a paper feed roller 68, a separation roller 69, a separation pad 70, a registration roller pair 71, and the like. The paper feed tray 67 is provided with a plurality of paper size detection sensors 73 that detect the size of the print paper P stacked on the upper surface thereof.

  The plate discharging unit 5 disposed on the upper left side of the printing unit 2 is also a well-known one having an upper plate discharging member 74, a lower plate discharging member 75, a plate discharging box 76, a compression plate 77, and the like. Then, the master-making master 66 is peeled off from the outer peripheral surface of the plate cylinder 12 and discarded in the discharge plate box 76.

  A paper discharge unit 6 is provided below the plate discharge unit 5. The paper discharge unit 6 is a well-known unit having a peeling claw 84, a paper discharge transport unit 85, a paper discharge tray 86, and the like. The print paper P is peeled off from the outer peripheral surface of the plate cylinder 12 and placed on the paper discharge tray 86. Discharge. The front end of the printing paper P (the front end in the paper conveyance direction) is lifted from the outer peripheral surface of the plate cylinder 12 and is provided with a blowing means such as a printing paper peeling fan or an air nozzle for assisting the peeling by the peeling claw 84. May be.

  An image reading unit 7 is provided on the upper part of the printing apparatus main body 11. The image reading unit 7 includes a contact glass 93 on which a document is placed, a pressure plate 94 provided so as to be able to come in contact with and away from the contact glass 93, reflection mirrors 95, 96, 97, 98 for scanning and reading a document image, and a fluorescent lamp. 99, a lens 100 for focusing the reflected light related to the scanned document image, and an image sensor 101 for performing photoelectric conversion processing on the reflected light related to the focused document image. The document image reading operation is performed by the operation of the reading driving means 128 (see FIG. 4) including a scanner motor and the like.

  A dog 133 is attached to the outer surface of the flange constituting the plate cylinder 12, and a home position sensor 134 attached to the printing apparatus main body 11 is provided in the vicinity of the periphery of the plate cylinder 12. The home position sensor 134 detects the dog 133 when the plate cylinder 12 occupies a position where the clamper 19 faces the press roller 13 and transmits a detection signal to the control unit 150 (see FIG. 4) described later.

<control panel>
FIG. 3 is a schematic view of an operation panel in the double-sided stencil printing apparatus 1. Here, FIG. 3A shows the entire operation panel 200, and FIG. 3B shows an LCD (liquid crystal display unit) 212 and a part below it. The operation panel 200 is disposed on the upper front surface of the printing apparatus main body 11.

  As shown in FIG. 3A, on the upper surface of the operation panel 200, as various keys, a start key 201, a print key 202, a test print key 203, a continuous key 204, a clear / stop key 205, an enter key 206, a numeric key 207, a program In addition to known keys such as the key 208 and the mode clear key 209, an ink adjustment key 210 is provided.

  By providing the ink adjustment key 210, it is possible to set whether to enable automatic ink adjustment discrimination. At this time, it is desirable to store the setting contents of the ink adjustment key 210 in the control unit 150 (see FIG. 4) even when the apparatus is turned off. The setting means is not limited and may be stored in advance as a system setting value.

  Further, as shown in FIG. 3B, when the user is requested to make a determination about the operation, the requirement items are displayed on the LCD 212, and the user selects the timely option from the options displayed on the keys 213 to 216, and the keys 217 to 220 are displayed. You may comprise so that it may determine by pressing.

  3A and 3B are some of the keys that can be displayed on the operation panel 200, and various other keys such as a print mode (single-sided print mode, double-sided print mode) are available. Needless to say, a print mode key (single-sided printing key, double-sided printing key) for setting can be displayed.

<Control system configuration>
FIG. 4 is a block diagram of a control system of the double-sided stencil printing apparatus 1.
The control unit 150 includes a CPU 151, a ROM 152, a RAM 153, and the like inside, and a microcomputer having a configuration in which they are connected by a bus. As shown in FIG. 1, the control unit 150 is provided in a control board arrangement unit in the printing apparatus main body 11.

  Based on various signals from the operation panel 200, detection signals from various sensors provided in the printing apparatus main body 11, and an operation program called from the ROM 152, the CPU 151 prints the printing unit 2, the plate making unit 3, the paper feeding unit 4, It controls each drive means provided in the plate discharge unit 5, paper discharge unit 6, image reading unit 7, conveyance member drive motor 122 provided in the refeed unit 9, operation of a solenoid 123 that operates the switching member 10, and the like. The operation of the entire duplex stencil printing apparatus 1 is controlled.

  The ROM 152 stores an operation program for the entire double-sided stencil printing apparatus 1, and this operation program is appropriately called by the CPU 151. The RAM 153 has a function of temporarily storing calculation processing results of the CPU 151, a function of setting the various keys and various sensors described above, and a function of storing input data signals and on / off signals as needed.

  The control unit 150 also grasps the rotation position of the plate cylinder 12 based on the home position signal from the home position sensor 134 and the signal from the encoder provided in the printing drum driving unit 121.

  As will be described later, the CPU 151 of the control unit 150 includes a printing paper size determining unit, a final printing elapsed time measuring unit, an ink adjustment mode setting unit, a paper feed timing setting unit, a plate making area setting unit, and a single side / double side switching determination unit. Function as such. In the explanatory text relating to the flowchart (FIG. 5) to be described later, these means are described as “printing paper size determining means of the CPU 151” and the like.

<Normal plate making printing>
Normal plate-making printing in the double-sided stencil machine 1 will be described. Normal plate-making printing includes double-sided printing and single-sided printing, and will be described in order.

<Double-sided printing>
When a document is set on the image reading unit 7 and the user presses the duplex printing key on the operation panel 200, the setting of duplex printing is stored in the ROM 152 of the control unit 150, and the operation program for duplex printing is called up. It is. Thereafter, when the start key 201 is pressed, the image reading unit 7 performs the reading operation of the document image and the plate discharging unit 5 is operated to use the divided master-making master 65 or the plate-making completed from the outer peripheral surface of the plate cylinder 12. The master 66 is peeled off. After the plate removal, the plate making unit 3 is operated to form the first plate making image 65 a and the second plate making image 65 b on the master 64, and a new divided plate making master 65 is made and is wound around the plate cylinder 12. .

  After the winding operation is completed and the double-sided stencil printing apparatus 1 enters the double-sided printing standby state, when the print key 202 is pressed after setting various printing conditions, the plate cylinder 12 is driven to rotate at the set speed and the paper feeding unit 4, one sheet of double-sided printing paper (for example, A4 size) is fed as the printing paper P. The fed printing paper P is temporarily stopped by the registration roller pair 71 and then fed toward the printing nip portion between the plate cylinder 12 and the press roller 13 at a predetermined timing. Various printing conditions may be set before the start key 201 is pressed.

  When the plate cylinder 12 is rotated to a predetermined angle and the surface area 12a occupies a predetermined position corresponding to the press roller 13, the press roller 13 occupies the press contact position, whereby the printing paper P is divided on the plate cylinder 12. The first master-making image 65a of the finished master 65 is pressed and the surface image is transferred to one surface (front surface).

  The printing paper P that has become the front surface printed paper is peeled off from the outer peripheral surface of the plate cylinder 12 by the tip of the switching member 10 occupying the second position, and is sent to the refeed conveyance unit 25. At this time, the front end of the printing paper P is guided by the guide plate 56 and is placed on the auxiliary tray 8 from the rear end side. The printing paper P on the auxiliary tray 8 is transported in the direction of the arrow in FIG. 1 by the paper refeeding transport unit 25, and temporarily stops with its leading end abutting against the paper refeeding positioning member 24.

  The plate cylinder 12 continues to rotate while the first printing paper P is being guided onto the auxiliary tray 8, and the second printing paper P is fed from the paper supply unit 4 at the same timing as the first printing paper P. Printing paper P is fed. The fed second printing paper P, like the first printing paper P, occupies the second position after the first plate-making image 65a is transferred to one surface thereof by the press roller 13. The re-feeding conveyance unit 25 is sent by the switching member 10.

  After the second printing paper P is fed from the paper feeding unit 4, the re-feeding registration roller 23 is a little earlier than the back surface area 12 b of the plate cylinder 12 reaches the position corresponding to the press roller 13. Is activated and the first printing paper P stored on the auxiliary tray 8 is pressed against the peripheral surface of the press roller 13. The first printing paper P pressed against the peripheral surface of the press roller 13 is conveyed toward the contact portion with the plate cylinder 12 by the rotational force of the press roller 13 that is in contact with the plate cylinder 12 and is driven to rotate. Then, by pressing against the second plate-making image 65b of the divided plate-making master 65, the back image is transferred to the other surface (back surface).

  The first printing paper 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, and the plate cylinder is formed by the tip of the peeling claw 84. 12 is peeled off from the outer peripheral surface. The peeled double-side printed printing paper P is sent to the paper discharge transport unit 85 and then discharged onto the paper discharge tray 86 and stacked.

  Thereafter, the above operation is repeated, and when the set number of duplex printings is completed, the operation of each part is stopped.

<Single-sided printing>
When a document is set in the image reading unit 7 and the user presses the single-sided printing key on the operation panel 200, the fact that single-sided printing has been set is stored in the control unit 150, and an operation program for single-sided printing is called. Thereafter, when the user presses the start key 201, the image reading unit 7 performs a document image reading operation and the plate discharging unit 5 operates to use the divided master-made master 65 or the used master plate 65 from the outer peripheral surface of the plate cylinder 12. The master-making master 66 is peeled off. After the plate removal, the plate making unit 3 is operated to form a third plate making image 66 a on the master 64 to make a new plate making master 66, which is wound around the plate cylinder 12.

  After the winding operation is completed and the double-sided stencil printing apparatus 1 enters the single-sided printing standby state, when the print key 202 is pressed by the operator after setting various printing conditions, the plate cylinder 12 is rotated at a set speed, and One sheet of single-sided printing paper (for example, A3 size) is fed from the paper supply unit 4 as the printing paper P. The fed printing paper P is temporarily stopped by the registration roller pair 71 and then fed toward the printing nip portion between the plate cylinder 12 and the press roller 13 at a predetermined timing.

  When the plate cylinder 12 is rotated to a predetermined angle and the surface area 12a occupies a position corresponding to the press roller 13, the press roller 13 occupies the press contact position, whereby the printing paper P is made on the plate making master 66 on the plate cylinder 12. The third plate-making image 66a is pressed and the image is transferred.

  The printing paper P that has been printed after the image is transferred is guided to the paper discharge unit 6 by the switching member 10 occupying the first position, and is peeled off from the outer peripheral surface of the plate cylinder 12 by the end of the peeling claw 84. The peeled print paper P is sent to the paper discharge transport unit 85, and is then discharged and stacked on the paper discharge tray 86.

  Thereafter, the above operation is repeated, and when the set number of single-sided printings are completed, the operation of each part is stopped.

<Plate-making printing peculiar to this embodiment>
The normal plate-making printing in the double-sided stencil printing apparatus 1 according to this embodiment has been described above. Next, plate making printing unique to the double-sided stencil printing apparatus 1 according to the present embodiment will be described. FIG. 5 is a flowchart of the plate-making printing operation unique to the double-sided stencil printing apparatus 1.

  In FIG. 5, after the double-sided stencil printing apparatus 1 is turned on or returned from the low power mode, the final printing elapsed time measuring means of the CPU 151 measures the elapsed time from the last printing (previous printing), It is determined whether or not the ink adjustment execution determination time set in the printing apparatus 1 is within the range (step S1). Here, the determination time is preferably set in advance by the double-sided stencil printing apparatus 1, but may be set by a user or a service person.

  If the elapsed time is less than the set value (step S1: less than the set value), it is determined that the ink adjustment is unnecessary, and the process proceeds to the above-described normal plate-making printing. If the determination is impossible because the elapsed time is equal to or greater than the set value or the final printing elapsed time measuring means is not provided in the double-sided stencil printing apparatus (step S1: greater than the set value or determination is impossible), the process proceeds to step S2. To do.

  In step S2, it is determined whether or not to perform ink adjustment. About this determination, whether or not automatic discrimination is performed can be set with the ink adjustment key 210 or the like provided on the operation panel 200 of the double-sided stencil printing apparatus 1 in advance. It may be programmed to automatically set the execution according to the measurement result of the final printing elapsed time measurement means, or the measurement result of the final printing elapsed time measurement means without setting whether to perform automatic discrimination. It may be programmed to automatically set the execution of ink adjustment based on the above, or a method of confirming whether or not the ink adjustment is performed on the LCD 212 of the operation panel 200 as shown in FIG. 3B may be used.

  If it is determined in step S2 that ink adjustment is not performed (step S2: none), the process proceeds to the above-described normal plate-making printing. On the other hand, if it is determined to be executed (step S2: yes), the process proceeds to step S3, where the paper size used in the duplex stencil printing apparatus 1 is identified or set. That is, when the paper size detection sensor is mounted on the paper feed tray or the like (in this embodiment, the paper size detection sensor 73 is provided on the paper feed tray 67, and this case applies), the CPU 151. The printing paper size discriminating means discriminates the printing paper size. At this time, it is more desirable to display the determination result on the operation panel 200 and notify the user. Further, even when a sensor capable of detecting the used paper size is not installed in the double-sided stencil printing apparatus or when it is determined to be indeterminate, the determination result is displayed on the operation panel 200 to allow the user to check the printing paper size, Let it be set.

  As a result of the above identification or setting, if the used paper is for single-sided printing (for example, A3) (step S3: single-sided), ink adjustment is performed in the full-surface ink adjustment mode. Ink adjustment in the full-surface ink adjustment mode is a known ink adjustment in which discard printing is performed using printing paper for single-sided printing.

  As a result of the above identification or setting, if the used paper is for double-sided printing (for example, A4) (step S3: for double-sided), ink adjustment (steps S4 to S12) according to the present embodiment is executed.

  Before describing steps S4 to S12, an outline of ink adjustment executed in these steps will be described. The ink adjustment modes executed in steps S4 to S12 include a single-sided ink adjustment mode and a double-sided ink adjustment mode. In the single-sided ink adjustment mode, discard printing is performed only on one side of the printing paper for double-sided printing, and in the double-sided ink adjustment mode, discarding printing is performed on both sides of the double-sided printing paper. The ink adjustment in the double-sided ink adjustment mode is not performed independently, but is performed after the ink adjustment in the single-sided ink adjustment mode.

  First, in step S4, it is determined whether or not it is necessary to change the plate making area at the time of ink adjustment. In the ink adjustment according to the present embodiment, it is possible to adjust the sheet feeding timing and the plate making area in the single-sided ink adjustment mode from the result of the final printing elapsed time measuring unit.

  As described above, when the viscosity of the emulsion ink in the printing drum is left unattended, the emulsion state is destroyed and the viscosity decreases. In other words, it is possible to grasp the approximate viscosity of the ink by grasping the elapsed time from the final printing. Therefore, the double-sided stencil printing apparatus 1 is configured such that the measurement value of the final printing elapsed time measuring unit of the CPU 151 can be used as the condition setting parameter at the time of ink adjustment by the ink adjustment mode setting unit of the CPU 151.

  When printing is performed using emulsion ink with reduced viscosity, if excessive ink adheres to the surface of the printing paper, the sticking force between the printing drum and the printing paper increases, and the sticking force is greater than the peeling force. In this case, it cannot be peeled off from the printing drum, resulting in a paper discharge jam.

  As a countermeasure, it is effective to widen the margin at the front end (front end in the transport direction) of the printing paper. This is because widening the margin makes it easier for the air from the blowing means for peeling the printing paper to enter between the printing paper and the printing drum, so that the printing paper can be peeled stably.

  Therefore, the double-sided stencil printing apparatus 1 is configured to measure the elapsed time from the final printing, advance the paper feed timing according to the ink viscosity, and automatically ensure the leading edge margin of the printing paper.

  However, depending on the timing change, the margin at the trailing edge of the printing paper disappears, and the press roller 13 is soiled when the plate making area is near the trailing edge of the printing paper or behind the trailing edge of the printing paper. Become.

  Therefore, in order to prevent this, the plate making area setting means of the CPU 151 makes the plate making area in the sub-scanning direction more than the plate making area during normal double-sided printing by the plate making area setting means of the CPU 151 when necessary. The control is narrowing. As described above, the double-sided stencil printing apparatus 1 is configured to automatically adjust the sheet feeding timing and the plate making area according to the elapsed time from the final printing, and the plate making area needs to be changed in step S4. If it is determined, the plate making area is changed.

  If it is determined in step S4 that the platemaking area needs to be changed (S4: required), the process proceeds to step S5 to select whether or not to repeatedly perform platemaking. In order to remove the ink left on the printing drum in a short time, it is effective to repeat the plate making and attach the ink to the discharged master to be discarded, but on the other hand, the consumption of the master increases. Depending on the user, there is a case where it is desired to suppress the consumption of the master due to the ink adjustment as much as possible, so that it is possible to select whether or not the repeated plate making can be performed in step S5.

  When repetitive plate making is performed (step S5: execution), the process proceeds to step S6, and the number of plate making is set. Here, the number of times of plate making may be set automatically or may be set by the user through the operation panel 200.

  When repetitive plate making is not performed (step S5: not performed), the process proceeds to step S11, and single-sided ink adjustment is performed. As will be described in detail later, in the single-sided ink adjustment, one sheet of double-sided printing paper is supplied for one rotation of the plate cylinder 12 and printing is performed only on the surface of the printing paper.

  When the number of plate making is set in step S6, the process proceeds to step S7, and it is selected whether or not double-sided ink adjustment (operation in the double-sided ink adjustment mode) is to be performed at the time of repeated plate making. In this double-sided ink adjustment, ink is adjusted in the two areas of the first side and the second side by one rotation of the printing drum, which is effective in suppressing consumption of printing paper and shortening the ink adjustment time.

  However, if the double-sided ink adjustment is performed and the refeed unit 9 is used when the ink viscosity is greatly reduced, the refeed unit 9 and the like are soiled with ink, and stable transport quality cannot be ensured. Therefore, this problem is solved by performing double-sided ink adjustment after executing several plate-making printing operations by single-sided ink adjustment. That is, if the ink whose viscosity has decreased substantially by the single-sided ink adjustment can be removed and the ink adjustment is still necessary even though it has almost no effect on the paper conveyance, the refeed unit 9 is continuously used. Thus, the printing is also performed on the back side of the double-sided printing paper.

  In step S7, when it is determined by the single-sided / double-sided switching determination unit of the CPU 151 that execution of double-sided ink adjustment is selected (step S7: execution), the number of plates for single-sided ink adjustment (up to double-sided ink adjustment) (Employed plate number) is set (step S8), and after adjusting the one-sided ink for the planned number of plates (step S9 → S10: end), the double-sided ink adjustment mode is switched to (step S12).

  If it is determined in step S7 that execution of double-sided ink adjustment is not selected (step S7: not executed), the process proceeds to step S11 and the single-sided ink adjustment is executed as in the case of not performing repeated plate-making. .

<Printing pressure and plate making area during plate making printing operation>
FIG. 6 is a diagram for explaining the printing pressure and the plate making area during the plate making printing operation of the double-sided stencil printing apparatus 1.

  The “conventional printing pressure range”, “master punching during duplex printing”, and “conventional printing image (double-sided printing)” in FIG. 6 are the printing pressure range during duplex printing and the duplex printing master 65 of the above-described normal printing. A first image 65a, a second image 65b, and a print image on a printing paper for double-sided printing are shown. In the “conventional print image (double-sided printing)”, “front” and “back” indicate that the paper is conveyed to the paper discharge tray 86 and the paper re-feeding unit 9 after printing, and P1a and P1b In the same manner, one side and the other side of the first double-sided printing paper P1 are represented, P2a, P2b and P3a, P3b are the second printing paper P2 and the third printing paper, respectively. One side and the other side of the paper P3 are shown.

  Further, “conventional print image (printing two drums at one rotation)” represents a printing image in which printing is performed only on one side of two double-sided printing sheets for one rotation of the printing drum. ”And“ back ”and P1a to P4a have the same meaning as in the case of“ conventional print image (double-sided printing) ”.

  As described above, in normal plate-making printing, the press roller 13 is pressed against each of the first and second surfaces by one rotation of the printing drum to apply printing pressure.

  On the other hand, in the single-sided ink adjustment in the present embodiment, as shown in the “embodiment print image”, printing pressure is alternately applied to either the first side or the second side for one rotation of the printing drum. Yes. As a result, ink adjustment can be performed on any surface. Further, compared to the case where ink adjustment is performed in the “conventional print image (printing with one drum rotating twice)”, a sufficient space can be provided between the respective print sheets. The collision between them can be suppressed.

  In addition, as shown in “embodiment printing image (when feeding timing / plate making area is changed)”, even when the paper feeding timing of printing paper is advanced to ensure a margin at the leading edge of printing paper, As shown as “area change master punching area”, the plate making areas 65a ′ and 65b ′ are changed in a form corresponding to the variable amount, so that the image protrudes from the rear end of the printing paper to the press roller 13. Printing can be performed in a state where ink is not adhered.

  In addition, when making multiple plates and performing ink adjustment, it is configured to perform double-sided ink adjustment using the refeed unit 9 after adjusting the single-sided ink for the planned number of plates. Ink adjustment that does not occur can be realized with the configuration of the current double-sided stencil printing apparatus.

  Also, when making multiple plates, it is easy to adjust the paper feed timing and plate making area for each plate making printing from the ink adjustment level. In that case, it is closer to the actual plate making area and in a wide range. Ink adjustment is possible.

  That is, for example, the plate making area is adjusted as follows. When making a plate for the first time when the ink viscosity is low (loose), the ink adjustment plate making area is narrower than the actual plate making area for the purpose of improving paper discharge performance. Widen the tip margin. After that, when performing the second plate-making for the first plate-making part, the loose ink is removed by the master plate removal and the first plate-making (+ plate printing), and the viscosity of the ink in the printing drum is restored. Since the influence on the paper discharge performance is reduced, the plate making area for ink adjustment is expanded from the first time to reduce the leading edge margin.

  This brings the ink adjustment range closer to the actual plate making area. The number of plate making at this time varies depending on the degree of decrease in viscosity. Ink is removed by making the plate without changing the plate making area and discharging the master. However, plate making and printing are performed at the part corresponding to the actual use range (= actual plate making area) (from the drum opening to the printing paper). Supplying ink) is more effective for ink removal.

  Note that the user may be able to set the paper feed timing and the amount of change of the plate making area. However, since it is necessary to be familiar with the printing system, the control unit is required to execute it with certainty. It is better to set it at 150.

As described above in detail, according to the double-sided stencil printing apparatus 1 according to the embodiment of the present invention, the following effects (1) to (6) can be obtained.
(1) When discarding plate making printing for ink adjustment is performed using printing paper for double-sided printing, the first plate making image 65a or the second plate making is performed by rotating the printing drum once without passing through the refeed unit 9. Since any one of the images corresponding to the image 65b is alternately printed, the printing paper originally transported to the refeed unit 9 is directly transported linearly to the paper discharge tray 86. Even if the printing paper is excessively transferred, the ink on the surface of the printing paper does not adhere to the conveyance path such as the paper refeeding section 9, so that stable conveyance quality can be ensured continuously.
(2) By performing the operation of the ink adjustment mode automatically according to the elapsed time from the final printing, it is possible to grasp the state of the ink in the printing drum and implement the ink adjustment mode according to the state. For this reason, even a user who does not have a deep understanding of the operation of the double-sided stencil printing apparatus 1 can surely carry out optimal ink adjustment.
(3) When performing ink adjustment, the plate making area in the sub-scanning direction on the first side and the second side is set to normal both sides even if the leading edge of the printing paper is widened by making the paper feeding timing earlier than that for normal plate making printing. By narrowing from the plate making area at the time of printing, the master opening and the press roller 13 are not in direct contact and the press roller 13 is not soiled. If two sheets are printed with one rotation of the drum without using the refeed unit 9 without this configuration, ink smearing in the refeed unit 9 is eliminated, but a large margin at the tip cannot be taken. There remains a problem that the transport quality cannot be ensured without removing the paper from the printing drum.
(4) By changing the paper feed timing and plate making area for each elapsed time from the last printing and for each plate making in ink adjustment, it becomes possible to carry out ink adjustment according to the ink state, and more actual plate making area The ink can be adjusted over a wide range.
(5) After removing moderately low-viscosity ink by single-sided ink adjustment, by carrying out double-sided ink adjustment that performs two-sided discard printing on the first and second sides on one double-sided printing paper In addition, while ensuring the reliability of ink adjustment at the time of ink adjustment, it is possible to reduce consumption of printing paper used at the time of ink adjustment and shorten the ink adjustment time.
(6) When performing pre-printing printing for ink adjustment using printing paper for double-sided printing, the printing paper is conveyed linearly from the printing drum directly to the paper discharge tray 86, so the air for separating the printing paper In the case of the configuration in which the means is provided, the air blowing is performed without being impaired by the movement of the switching member 10 that guides the printing paper to the refeed unit 9. As a result, even printing paper on which ink has been excessively transferred for discard printing can be reliably peeled off from the printing drum.

  DESCRIPTION OF SYMBOLS 3 ... Plate making part, 2 ... Printing part, 4 ... Paper feed part, 6 ... Paper discharge part, 9 ... Refeeding part, 12 ... Plate cylinder, 13 ... Press roller, 64 ... Master, 65 ... Divided pre-printed master, 65a ... first plate-making image, 65b ... second plate-making image, 150 ... control unit, P, P1 to P3 ... printing paper, Pa ... one surface of printing paper, Pb ... other surface of printing paper.

JP 2003-266906 A JP-A-9-174992

Claims (9)

A plate making section for making a master plate,
A printing drum around which a double-sided plate making master on which the first plate making image and the second plate making image are lined up by the plate making unit is wound, and a printing unit having a pressing means that can be brought into contact with and separated from the printing drum;
A paper feeding unit for feeding printing paper to the printing unit;
A paper discharge unit for discharging printed printing paper on which predetermined printing has been completed in the printing unit;
When the predetermined printing is double-sided printing, a printing paper for double-sided printing on which one of the first plate-making image or the second plate-making image is printed on the surface in the printing unit is used as the first plate-making image or A refeed unit that feeds the second plate-making image toward the printing unit in order to print the other side of the second plate-making image;
Have
Operation for supplying one sheet of printing paper for duplex printing to one rotation of the printing drum, printing one of the first plate-making image or the second plate-making image, and discharging the paper by the paper discharge unit And a double-sided stencil printing apparatus having a single-sided ink adjustment mode in which the other of the first plate-making image or the second plate-making image is printed and discharged by the paper discharge unit. In the double-sided stencil printing apparatus according to claim 1,
A double-sided stencil printing apparatus having elapsed time measuring means for measuring an elapsed time since the previous printing, and performing ink adjustment in the single-sided ink adjustment mode when the elapsed time is a predetermined value or more. In the double-sided stencil printing apparatus according to claim 1 or 2,
Plate making narrows the plate making area in the sub-scanning direction of the first plate making image and the second plate making image when performing ink adjustment in the single-sided ink adjustment mode to be smaller than the plate making area when performing double-sided printing as the predetermined printing. A double-sided stencil printing apparatus having area setting means. In the double-sided stencil printing apparatus according to claim 3,
The plate-making area setting unit is a double-sided stencil printing apparatus that sets the plate-making area according to the elapsed time measured by the elapsed time measuring unit. In the double-sided stencil printing device according to any one of claims 1 to 4,
A double-sided stencil printing apparatus comprising paper feed timing setting means for setting the paper feed timing of the printing paper. In the double-sided stencil printing apparatus according to claim 3 or 4,
A double-sided stencil printing apparatus, wherein when the plate making unit makes a plurality of plates and ink adjustment is performed in the single-sided ink adjustment mode, the plate making region setting means can change the plate making region for each plate making. In the double-sided stencil printing apparatus according to claim 5,
The double-sided stencil printing apparatus, wherein when a plurality of plates are made in the plate making unit and ink adjustment is performed in the single-sided ink adjustment mode, the paper feed timing setting means can set a paper feed timing for each plate making. In the double-sided stencil printing apparatus according to any one of claims 1 to 5,
As the ink adjustment mode, there is a double-sided ink adjustment mode in which the first plate-making image and the second plate-making image are printed on a printing paper for double-sided printing, and discharged by the paper discharge unit. A double-sided stencil printing apparatus capable of switching to the double-sided ink adjustment mode after performing the operation. A double-side plate-making master on which a first plate-making image and a second plate-making image are made side by side is wound around the outer peripheral surface of the printing drum, and the double-side plate-making on the printing drum is pressed by a pressing means that can be brought into contact with and separated from the printing drum. After printing one of the first plate-making image or the second plate-making image by pressing the surface of the printing paper for double-sided printing on the master, the printing paper is reversed and re-fed, and the pressing means An ink adjustment method in a double-sided stencil printing apparatus having a function of pressing the back side of the printing paper and printing the other of the first plate-making image or the second plate-making image,
A first printing step of printing one of the first plate-making image or the second plate-making image on one surface of one double-sided printing paper by one rotation of the printing drum;
A first paper discharge step of discharging the printing paper printed in the first printing step;
A second printing step of printing the other of the first plate-making image or the second plate-making image on the one surface of one double-sided printing paper by one rotation of the printing drum;
A second discharge step of discharging the printing paper printed in the second printing step;
Having
Ink adjustment method in a double-sided stencil printing apparatus.

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