JP2009137094A - Ink circulation mechanism of rotary screen printing machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent uneven ink supply to a squeegee due to a long-time stay of deteriorated ink in a plate cylinder, by continuously circulating the ink during the operation of a printing machine. <P>SOLUTION: Inside an ink tank of the machine, this ink circulation mechanism of the rotary screen printing machine is equipped with an agitating means for making ink viscosity uniform, a viscosity measuring means for measuring the ink viscosity and a temperature adjusting means which compares the measured viscosity with the viscosity set beforehand and performs operation. Outside the ink tank, the mechanism is equipped with a reserve ink tank which supplies unsupplied ink to the ink tank and a dilution water tank which supplies dilution water for attaining the set ink viscosity. A certain inclination is given to the squeegee so as to improve the rate of recovery of the ink. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an ink circulation mechanism of a printing press that performs rotary screen printing.

  Conventionally, screen printing has been known as a printing method for a wide range of materials such as metal, cloth, and paper. Screen printing is a printing method in which ink is transferred to a printing material through a through-hole formed in the plate surface. The printing plate has two types of shapes, and is classified into a flat type using a flat plate surface and a rotary type using a cylindrical printing plate (plate cylinder). Since the rotary type can be printed by continuously rotating the plate cylinder, the speed can be increased as compared with the flat type.

  An apparatus using rotary screen printing is also called a rotary screen printing machine, and its configuration includes a paper feeding unit, a printing unit, a paper discharge unit, and the like. The printed materials are sequentially fed by the paper feeding unit and conveyed to the printing unit. Next, the material to be printed in the printing unit is pressed against the impression cylinder and the plate cylinder and printed. At this time, the ink is supplied to the plate cylinder by discharging ink from the ink supply means provided in the plate cylinder toward the lower side of the rotating plate cylinder. Further, the ink staying at the lower part of the plate cylinder moves to the uppermost part with the rotation of the plate cylinder, and is pushed into the through hole of the plate cylinder while the excess ink is scraped off by the squeegee located at this position. After that, the ink pressed into the through-hole is transferred to the printing material by pressing the printing material with the impression cylinder and the plate cylinder, and after the ink is transferred to the non-printing material, the rotary screen printer from the paper discharge unit It is discharged outside.

  However, during the operation of the rotary screen printer, the ink scraped off by the squeegee may always stay in the plate cylinder. For this reason, when new ink is supplied from the ink supply means, the viscosity of the new ink and the ink that stays stagnates, and the unevenness of the image line is generated due to the non-uniform pressing of the ink into the through holes. As a method for preventing the unevenness of the image line, there is a method of reducing the viscosity difference of the ink by excessively supplying the ink into the plate cylinder and increasing the total amount of the ink. The load of cleaning work increases. For this reason, a rotary screen printer has conventionally been provided with various ink collecting means.

  For example, a kneading apparatus driven by a motor, an ink supply pipe connected to the kneading apparatus, and a stencil printing apparatus provided with an ink amount sensor in a plate cylinder are disclosed (for example, see Patent Document 1). As the ink supply means, the ink is kneaded by a kneading device and supplied from the ink supply pipe into the plate cylinder to form an ink reservoir. The amount of ink in the ink reservoir is limited by an ink amount sensor. The ink collecting means sucks ink from the ink reservoir through the ink supply pipe by driving the motor in reverse when printing is completed. The ink can be used again by collecting it in the kneading apparatus.

  In addition, in the ink drum, there is disclosed a recovery device for residual ink or the like in which a squeegee that is in contact with the ink drum on the inner surface of the ink drum and a recovery container are provided (for example, see Patent Document 2). By rotating the ink drum to which the ink has adhered, when the ink is scraped off by the squeegee, it spontaneously falls and falls into the collection container. The ink is reused by stopping the ink drum and removing the collection container after collection.

  Furthermore, a method for managing the viscosity of ink in a screen printing apparatus provided with a screen plate and a squeegee that is moved by an electric motor is disclosed (for example, see Patent Document 3). As a method for managing the viscosity of the ink, the ink supplied onto the screen plate is moved along the upper surface of the screen plate and transferred to the substrate. At this time, by detecting the power consumption of the electric motor during the movement of the squeegee, a change in the force required for the movement is detected, and the viscosity of the ink is detected. When the ink viscosity deviates from the predetermined range, the apparatus is stopped, the ink viscosity is adjusted, the apparatus is operated again, and printing is resumed.

Japanese Patent No. 3300718 No. 7-30359 Japanese Patent Laid-Open No. 10-128952

  However, in the stencil printing apparatus disclosed in Patent Document 1, since the motor is driven in reverse to collect ink when printing is completed, there is no ink collecting means when the apparatus is in operation, and the ink remains in the plate cylinder unevenly. If the ink deteriorates and clogs the through-holes, there is a risk of causing unevenness in the image line. Also, the viscosity of the ink is detected by adding a kneading device, but in general, the ink has a characteristic that the viscosity varies depending on the temperature, such as high viscosity at low temperature and low viscosity at high temperature. There is also a possibility of causing unevenness of the image line due to the temperature change of the ink. Further, since the motor, the kneading device, and the like are all provided in the plate cylinder and in the printing machine main body, the stencil printing device becomes larger and the ink circulation path becomes complicated accordingly.

  Further, in the recovery device such as residual ink disclosed in Patent Document 2, after the ink is scraped off into the recovery container by the squeegee, the above-mentioned device is stopped and recovered, so that by continuously operating, If the recovered ink overflows from the recovery container, there is a risk of reattaching to the ink drum. In addition, if the collected ink is a small amount, it must be reclaimed, and after removing the ink adhering to the inner surface of the collection container, it is necessary to return the ink to the ink supply means. There was a problem that occurred.

  Furthermore, in the ink viscosity management method in screen printing disclosed in Patent Document 3, the apparatus is stopped when the ink viscosity on the screen plate is out of a predetermined range, and after adjusting the viscosity of the ink, the apparatus is again operated. To resume printing. Therefore, there is no means for managing the viscosity of the ink before printing and during operation of the apparatus, and there is a possibility that ink having a non-uniform viscosity is supplied onto the plate surface. Further, since the ink viscosity is controlled by detecting the power consumption of electricity when the squeegee is moved, there is a problem that it cannot be installed in a rotary screen printing machine in which the squeegee is fixedly installed.

  The present invention aims to solve the above-mentioned problems. Specifically, in an ink circulation mechanism of a rotary screen printing machine, the ink is continuously circulated while the printing machine is operating, and the ink deteriorated in the plate cylinder. An object of the present invention is to prevent ink supply unevenness to the squeegee due to the fact that the ink stays for a long time. Another object of the present invention is to provide an ink circulation mechanism of a rotary screen printer that can easily and continuously perform viscosity control of ink before supply and recovered ink.

  In order to achieve the above-mentioned object, the invention of claim 1 is characterized in that an ink supply means supported downwardly with respect to a support in a plate cylinder of a rotary screen printing machine, and an ink supplied by the ink supply means. Squeegee supported upward with respect to the support to be taken, and an ink collecting means for collecting the ink scraped by the squeegee, and an ink collecting pump for sucking the ink collected by the collecting means outside the plate cylinder of the printing press And an ink tank for storing ink sucked by the ink recovery pump and unsupplied ink, and an ink supply pump for supplying the ink stored in the ink tank into the plate cylinder, and the viscosity of the ink recovered by the ink recovery means Ink circulation mechanism of rotary screen printer that measures viscosity, adjusts viscosity to obtain proper viscosity, and continuously supplies ink again The ink tank is provided with a stirring means for making the ink viscosity uniform in the ink tank. The viscosity measuring means for measuring the ink viscosity in the ink tank, the ink viscosity measured in advance by the viscosity measuring means, A temperature control means is provided that operates by comparing the set viscosity with a set value. Outside the ink tank, a reserve for supplying unsupplied ink into the ink tank in order to make the ink viscosity in the ink tank a preset viscosity. An ink circulation mechanism of a rotary screen printing machine comprising an ink tank and a dilution water tank for supplying dilution water to the ink tank in order to set the ink viscosity in the ink tank to a preset viscosity. is there.

  The invention according to claim 2 is the ink circulation mechanism of the rotary screen printing machine according to claim 1, wherein the ink collecting means collects the ink that has flowed down the surface of the support after being scraped off by the squeegee. And a heater that raises the temperature of the ink that has flowed down into the recovery container. The recovery container is provided with at least one recovery port connected to the ink recovery pump, and the recovery port is arranged in the horizontal direction below the support. Is provided so as to be inclined downstream.

  In an ink circulation mechanism in a rotary screen printing machine, ink can be circulated continuously during operation by providing an ink supply means and an ink recovery means inside the plate cylinder and an ink circulation means outside the plate cylinder. . In addition, agitation means, viscosity measurement means, and temperature adjustment means are provided in the ink tank, and a spare ink tank and dilution water tank are provided outside the ink tank, so that the viscosity management and viscosity adjustment of the ink can be performed at any time. It can be done easily and continuously at times.

  Further, the ink recovery means integrates the heater and the recovery container, and the recovery container is inclined so that the rotary screen printing machine can be efficiently heated and heated in the plate cylinder without increasing the size of the rotary screen printing machine. It can be recovered. In addition, since the ink circulation path in the ink circulation mechanism is simple, it is possible to reduce the work load when cleaning the inside of the plate cylinder and the pipe, and to shorten the cleaning time.

  Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a side view showing an embodiment in which an ink supply means (6), an ink recovery means (7) and an ink circulation means (11) are provided in a printing section (1) of a rotary screen printing machine according to the present invention. It is. FIG. 2 is a cross-sectional view showing an embodiment of the ink collecting means (7) provided in the printing section (1) of the rotary screen printer according to the present invention. The rotary screen printing machine includes a paper feed unit, a paper discharge unit, a printing unit (1), and the like (not shown).

  First, the substrate (P) fed by the sheet feeding unit one by one is conveyed to the printing unit (1) as indicated by the arrow in the figure. The printing unit (1) is composed of an impression cylinder (2) and a plate cylinder (3), and is disposed so as to face each other via a printing material (P). The impression cylinder (2) is supported by an axial core that can rotate at the center. The surface of the plate cylinder (3) has a hollow cylindrical shape with through holes formed therein, and is rotatably supported by connecting the end of the cylinder to a rotating body. During printing, the impression cylinder (2) is driven to rotate clockwise, and the plate cylinder (3) is driven to rotate counterclockwise.

  In the plate cylinder (3), a squeegee (4), a support (5), an ink supply means (6) and an ink recovery means (7) are provided. The squeegee (4) is fixed and installed upward by the support (5), and the tip of the squeegee (4) is in contact with the peripheral surface in the plate cylinder (3). The ink supply means (6) is fixedly installed downward by the support (5), and the ink recovery means (7) is installed at the lower part of the support (5). At the time of printing, the ink (E) is first supplied from the ink supply means (6) into the plate cylinder (3). The ink (E) moves in the direction in which the squeegee (4) is located with the rotation of the plate cylinder (3) while in contact with the plate cylinder (3). In the squeegee (4), the ink (E) is pushed into the through hole of the plate cylinder (3) and the excess ink is scraped off. The pressed ink (E) is transferred to the substrate (P) with the rotation of the impression cylinder (2) and the plate cylinder (3), and an ink pattern (e) is formed. On the other hand, the ink (E) that does not transfer to the substrate (P) is scraped off by the squeegee (4), and then flows down on the surface of the support (5) and falls to the ink collecting means (7). At this time, in order to improve the dropability of the ink (E), it is preferable that the surface of the support (5) has a shape without unevenness. In addition, although there is no restriction | limiting in the shape of a support body (5), A cylindrical shape is preferable.

  Next, the ink circulation means (11) provided outside the plate cylinder (3) will be described. The ink circulation means (11) includes an ink recovery pump (12), an ink tank (13), and an ink supply pump (14), which are connected by a pipe (15). The recovery port (10) provided in the recovery container (8) and the ink recovery pump (12) are connected via a pipe (15). By operating the ink recovery pump (12), ink is sucked from the recovery container (8) and sent to the ink tank (13) via the pipe (15).

  In the ink tank (13), stirring means (16), viscosity measuring means (17) and temperature adjusting means (18) are provided. The stirring means (16) in the ink tank (13) is a stirring blade and is rotated by a motor (not shown) to uniformly stir and mix the ink in the ink tank (13). The viscosity measuring means (17) measures the viscosity based on the electric power value by detecting the electric power of the motor that rotates the stirring blade. The temperature adjusting means (18) is a belt-like heater and is provided on the inner surface and the bottom surface of the ink tank (13). Further, it is preferable that the temperature adjusting means (18) has a control function for holding the ink viscosity in the ink tank (13) at a preset value arbitrarily set. The stirring means (16), the viscosity measuring means (17), and the temperature adjusting means (18) may be any shape provided in the ink tank (13), and may be set as appropriate without being limited to the above-described devices. Further, a preliminary ink tank (19) and a dilution water tank (20) are provided outside the ink tank (13). The preliminary ink tank (19) and the dilution water tank (20) are connected to the ink tank (13) via pipes (15), respectively. The ink (E) sucked from the recovery container (8) measures the ink viscosity by the viscosity measuring means (17) provided in the ink tank (13). The measured ink viscosity is compared with a set value that is arbitrarily set in advance. If the measured ink viscosity is larger than the allowable range, the temperature adjusting means (18) is operated to increase the ink temperature in the ink tank (13). If the ink viscosity is smaller than the allowable range, the temperature adjusting means (18) is operated to lower the ink temperature in the ink tank (13). At that time, the stirring means (16) may be operated, and dilution water and preliminary ink may be appropriately added from the preliminary ink tank (19) and dilution water tank (20) to the ink tank (13). By repeating these operations, the ink viscosity stored in the ink tank (13) becomes stable. The ink (E) whose viscosity is adjusted is supplied to the rotating plate cylinder (3) from the ink supply means (6) through the pipe (15) by the operation of the ink supply pump (14), thereby stably. The ink having an appropriate viscosity can be used again for printing. Further, by continuously operating the ink circulation means (11), it is possible to continuously supply ink having a stable viscosity and temperature into the plate cylinder (3) while controlling the viscosity of the ink.

  The ink supply pump (14) and the ink recovery pump (12) may be a linear actuator such as an air cylinder, a helical rotor pump, or the like.

  FIG. 2 is a cross-sectional view showing an embodiment of the ink collecting means (7) provided in the printing section (1) of the rotary screen printer according to the present invention. The ink recovery means (7) includes a recovery container (8) and a warmer (9). The recovery container (8) is provided with a recovery port (10) at one end, and is fixed to the lower part of the support (5) in an inclined state so that the recovery port (10) is downstream with respect to the horizontal direction. is set up. A warmer (8) is provided in the side part and bottom face part in a collection container (8). The temperature of the ink (E) dropped from the support (5) is increased by operating the heater (8), and the fluidity is improved. The ink (E) with improved fluidity moves to the recovery port (10) connected to the pipe (15) as shown in the direction of the arrow without staying in the inclined recovery container (8).

  The temperature of the warmer (9) may be set to a temperature that can impart fluidity to the ink (E) that falls into the recovery container (8). For example, the temperature ranges from room temperature +5 degrees to room temperature +30 degrees. And set as appropriate. In addition, when the preset temperature in the warmer (9) exceeds the normal temperature +30 degrees, the ink (E) may be deteriorated, which is not preferable. Conversely, if the set temperature in the heater (9) is less than room temperature +5 degrees, sufficient fluidity cannot be imparted to the ink (E), causing ink clogging at the recovery port (10). Is not preferable.

  The shape of the collection container (8) is preferably a toy shape. In addition, the inclination angle when the collection container (8) is fixedly installed on the support (5) can be appropriately set within a range that does not cause the ink (E) to stay. If the diameter (R) of the plate cylinder (3) is 300 mm and the plate cylinder length (L) is 1,200 mm, the size of the collection container (8) is 50 mm high × 60 mm wide × length 1 300 mm, and preferably 0.5 to 5 degrees with respect to the horizontal direction of the support (5). In addition, when the inclination angle in the collection container (8) exceeds 5 degrees, the ink (E) suddenly flows to the downstream part of the collection container (8) and cannot be collected from the collection port (10). Since it may overflow into the trunk (3), it is not preferable. Moreover, when the inclination angle in the collection container (8) is less than 0.5 degrees, the ink (E) does not move sufficiently to the collection port (10), which is not preferable.

  The shape and size of the ink collecting means (7) may be any shape and size that can collect the dropped ink (E), and is not limited to the above-described toy shape, and may be appropriately set to a semicircular shape or the like. . Further, a plurality of ink supply means (6) and recovery ports (10) in the above-described embodiment may be provided.

It is a figure which shows the side view which shows one Embodiment which provided the ink supply means, the ink collection | recovery means, and the ink circulation means in the printing part of the rotary screen printer concerning this invention. It is a figure which shows sectional drawing which shows embodiment of the ink collection | recovery means provided in the printing part of the rotary screen printer concerning this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Printing part 2 Impression cylinder 3 Plate cylinder 4 Squeegee 5 Support body 6 Ink supply means 7 Ink collection means 8 Collection container 9 Heater 10 Collection port 11 Ink circulation means 12 Ink collection pump 12 Ink tank 14 Ink supply pump 15 Pipe 16 Stirring means 17 Viscosity measuring means 18 Temperature adjusting means 19 Preliminary ink tank 20 Dilution water tank P Printed material E Ink e Ink pattern R Diameter L Plate cylinder length

Claims (2)

In the plate cylinder of the rotary screen printing machine, an ink supply means supported downward with respect to the support, and a squeegee supported upward with respect to the support that scrapes off the ink supplied by the ink supply means, An ink collecting means for collecting the ink scraped by the squeegee is provided, and an ink collecting pump for sucking the ink collected by the collecting means outside the plate cylinder of the printing machine, and the ink sucked by the ink collecting pump And an ink tank for storing unsupplied ink, and an ink supply pump for supplying the ink stored in the ink tank into the plate cylinder. The viscosity of the ink recovered by the ink recovery means is measured to obtain an appropriate viscosity. The ink circulation mechanism of a rotary screen printing machine that adjusts the viscosity in order to continuously supply the ink again,
In the ink tank, stirring means for making the ink viscosity in the ink tank uniform is provided, viscosity measuring means for measuring the ink viscosity in the ink tank, and ink viscosity measured by the viscosity measuring means A temperature adjusting means that operates by comparing with a preset viscosity set in advance is provided. Outside the ink tank, ink that has not been supplied in the ink tank is used to set the ink viscosity in the ink tank to a preset viscosity. Rotary screen printing characterized in that a preliminary ink tank for supplying the ink and a diluting water tank for supplying the diluting water in the ink tank to set the ink viscosity in the ink tank to a preset viscosity are provided. Ink circulation mechanism of the machine.   The ink recovery means comprises a recovery container that recovers ink that has been scraped off by the squeegee and then flows down on the surface of the support, and a heater that increases the temperature of the ink that has flowed down to the recovery container. The container is provided with at least one recovery port connected to the ink recovery pump, and is inclined with respect to the horizontal direction of the lower portion of the support body, the recovery port being downstream. Item 2. An ink circulation mechanism of a rotary screen printing machine according to Item 1.

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