JP2019116012A - Method for adjusting concentration of ink in printer - Google Patents

Abstract

To provide a method for adjusting concentrations of ink in a printer that can suppress wasteful sheets and match concentrations of the ink with target ink concentrations.SOLUTION: Respective apertures of a plurality of ink fountain keys K so that concentrations of ink are equal to target ink concentrations and therefore amounts of ink to be supplied from inside of an ink fountain to an ink fountain roller 21 are adjusted, and then the ink is supplied to a plate cylinder 1. A plurality of ink concentrations in regions corresponding to the ink fountain keys K respectively of a printed matter printed in test printing before main printing are measured. When at least one ink concentrations of the measured ink concentrations are higher than the target concentrations, ink on at least one roller 4a from the ink fountain roller 21 across the plate cylinder 1 is wiped out, and when all measured ink concentrations are lower than the target ink concentrations, the apertures of the ink fountain keys are adjusted based on the target ink concentrations to increase amounts of ink to be supplied to the ink fountain roller 21.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an ink density adjustment method in a printer configured to achieve a target ink density set within an allowable range between an upper limit value and a lower limit value.

  This printing press adjusts the amount of ink supplied from the inside of the ink fountain to the ink fountain roller by adjusting the opening degree of the plurality of ink fountain keys, and the ink fed to the ink fountain roller is called the ink feeding roller. Thus, the printing plate is supplied to the plate cylinder on which the printing plate is wound via a large number of ink roller groups, and the ink is moved from the plate cylinder to the impression cylinder via the blanket cylinder to print the printed matter.

  By the way, the ink flowability of the ink due to the difference in humidity and temperature at the time of printing changes, and the image of the printed matter printed last time is different from the image of the printed matter to be printed this time. The density may not match the target ink density. In order to solve this problem, test printing is performed for a predetermined number of sheets before main printing, the ink density of the predetermined printed matter is measured, and the allowable range in which the measured value is sandwiched between the upper limit and the lower limit If not, adjust the opening degree of the ink fountain key until the ink density of the printed matter falls within the allowable range. Then, even if the printed matter exceeds the predetermined number of sheets, if the measured value is not within the allowable range, a printing press for stopping the printing is already known (for example, Patent Document 1).

Patent No. 6214 862

  In the configuration of Patent Document 1, even while adjusting the opening degree of the ink fountain key until the ink density of the printed matter falls within the allowable range, the printed matter is being printed, so there is a disadvantage that waste paper increases. . In particular, since the printing machine is provided with a large number of ink roller groups, each of the large number of ink rollers has ink, so the thickness (density) of the ink on all the ink rollers can be determined immediately. It can not be changed. Therefore, since it takes a lot of time until the ink density of the printed matter falls within the allowable range, the printing of this time will increase waste paper.

  The present invention has been made to solve such problems, and an object thereof is to provide an ink density adjusting method in a printing press which can suppress waste paper and make the ink density coincide with a target ink density. It is.

  In order to achieve the above object, the ink density adjusting method in the printing press according to the present invention is such that the opening degree of each of a plurality of ink fountain keys is set to a target ink density set within an allowable range between upper limit and lower limit. By adjusting the amount of ink supplied from the inside of the ink fountain to the ink fountain roller, the ink supplied to the ink fountain roller is wound around the printing plate through a large number of ink roller groups by the call-up operation of the ink feeding roller. What is claimed is: 1. A method of adjusting the ink density of a printing press configured to be supplied to a rotated plate cylinder, comprising: ink in an area corresponding to each ink fountain key of a previous print or a print printed by a trial print before the current main printing. The concentration is measured, and when at least one of the plurality of measured ink concentrations is higher than the target ink concentration, If the ink on at least one of the roller, the ink feed roller, and the group of ink rollers is scraped across the entire width of the roller, and all the measured ink densities are lower than the target ink density, The opening degree of each ink fountain key is adjusted based on a target ink density to increase the amount of ink supplied to the ink fountain roller.

  According to the above configuration, when at least one of the measured ink concentrations is higher than the target ink concentration, the ink on the at least one roller is scraped off over the entire width of the roller. When all the measured ink densities are lower than the target ink density, the amount of ink supplied to the ink fountain roller is increased. By performing these operations, the time until convergence to the target ink concentration can be suppressed, so generation of waste paper can be suppressed.

  Further, in the ink density adjusting method in the printing press according to the present invention, the difference in density between the current ink density and the target ink density after scraping the ink on the at least one roller and the image line of the print image to be printed The opening degree of each ink fountain key may be determined based on the ink amount determined by the rate to increase the ink amount supplied to the ink fountain roller.

  As described above, the opening degree of each ink fountain key is determined based on the density difference from the current ink density after scraping off the ink on the roller and the ink amount determined by the streaking rate of the print image to be printed By this, it is possible to properly set the amount of ink to be increased, and to reliably reduce the time for matching the target ink density.

  Further, in the ink density adjusting method in the printing press according to the present invention, when all the measured ink densities are lower than the target ink density, the density difference between the target ink density and the current ink density and the print image to be printed The opening degree of each ink fountain key may be determined on the basis of the ink amount which is determined by the area coverage ratio, and the ink amount supplied to the ink fountain roller may be increased.

  As described above, the amount of ink is increased by determining the opening degree of each ink fountain key on the basis of the ink amount determined by the density difference between the target ink density and the current ink density and the print density of the print image to be printed The amount can be set properly and the time to match the target ink concentration can be reliably reduced.

  Further, the ink density adjusting method in the printing press according to the present invention corresponds to each ink fountain key of each of a plurality of printed matter from a predetermined sheet to a final sheet set in advance among a plurality of printed matter printed by the test printing. The ink density of the area to be measured is measured, the measured ink density is averaged for each ink fountain key, and the average ink density is compared with the target ink density to determine whether the target ink density is high or low. Good.

  As described above, the variation of the measurement result is suppressed by measuring the ink density of a plurality of printed matter from the preset predetermined sheet to the final sheet, in which the printing condition is easily stabilized by driving the printing machine. Can. Further, by averaging the plurality of measured ink densities for each ink fountain key, it is possible to absorb a measurement error at the time of measuring the ink density. Therefore, it is possible to suppress that the difference between the ink density and the target ink density largely deviates from the true value.

  According to the invention, if at least one ink density is higher than the target ink density, the ink on the at least one roller is scraped across the entire width of the roller, and all measured ink densities are greater than the target ink density. If the amount of ink supplied to the ink fountain roller is increased, the method of controlling the ink density in a printing press can be provided, which can suppress waste paper and make the ink density coincide with the target ink density. Can.

It is a schematic longitudinal side view of a printing press. It is an enlarged view of the ink supply part of a printing press. It is a block diagram of a control device which controls a printing press. (A) is an explanatory view showing measured values obtained by measuring the ink density in each ink fountain key, (b) is an explanatory view showing the ink density when the ink is scraped from (a), (c) is an ink from (b) It is explanatory drawing which shows the ink density after adding in the state which considered the drawing rate, (d) is an explanatory drawing which shows the ink density after adding a fixed amount of ink from (b). It is a flowchart which shows the ink adjustment method.

  Hereinafter, a printing machine used for the ink density adjustment method of the present invention will be described with reference to the drawings.

  FIG. 1 shows a printing press provided with a base ink adjustment mode, and shows a sheet-fed offset printing press (hereinafter simply referred to as a printing press). In this printing machine, a sheet feeding section A for feeding sheets as printing sheets one by one from a sheet stacker by a feeder device, a sheet separating apparatus, etc., and printing on sheets from the sheet feeding section A The printing unit B includes a printing unit B, a surface processing unit C for performing surface treatment on the sheet printed by the printing unit B, and a sheet discharging unit D for discharging the sheet. Here, the printing unit B is a printing unit B provided with four printing units 5 so that printing of four colors can be performed, but colors other than four colors, that is, one color or two colors or three colors, or five colors The printing unit may be capable of performing the above printing. The specific configuration of each part constituting the printing machine is not limited to that shown in FIG.

  The printing unit 5 comprises a plate cylinder 1, a blanket cylinder 2, an ink roller group 4, an impression cylinder 3 and a transfer cylinder 6. Although not shown, each of the impression cylinders 3 has two grippers (one or three or more) in the circumferential direction for gripping the fed sheet by the gripper and the claws. Have. Reference numeral 7 denotes a paper feed cylinder, which receives a sheet conveyed on the feeder board 8 and the mouth plate 9 from the swing arm 10 and plays a role of delivering it to the impression cylinder 3. The paper feed cylinder 7 and the swing arm 10 are also provided with the claw base and the claw. Further, a printing plate (not shown) on which an image is formed is wound and fixed to the plate cylinder 1.

  The discharge unit D is configured by a chain transfer device including two discharge cylinders and a gripper. That is, a first delivery cylinder 11 adjacent to the impression cylinder 3 of the surface treatment unit C and a second delivery cylinder 12 adjacent thereto are provided, and are provided on the front side (upstream side) of the sheet conveyance direction. An endless chain 15 is wound around the sprocket 13 and a sprocket 14 provided on the rear side (downstream side) of the sheet conveying direction, and is restricted by a chain guide (not shown) by the rotation of the sprockets 13 and 14 In this state, the chain 15 circulates. Sheets are discharged by being held by a plurality of chain grippers (not shown) fixed to the chain 15 at predetermined intervals.

  As shown in FIG. 1, the surface treatment unit C is provided with a varnish cylinder 16 which is in contact with the impression cylinder 3 and in contact therewith. Further, although not shown, an anilox roller which abuts on the varnish plate cylinder 16 and supplies the varnish is provided. The surface processing unit C is provided with a cylinder lifting device (not shown) for supporting the varnish cylinder 16 so as to be movable up and down with respect to the impression cylinder 3.

  FIG. 2 is an enlarged view of the ink supply unit. The ink fountain roller 21 to which the ink in the ink fountain is supplied rotates in the counterclockwise direction in the drawing, and supplies the ink to the many ink roller groups 4 located downstream via the ink feeding roller 25. Although not shown in detail, the ink feed roller 25 reciprocates so as to be able to contact and separate the ink fountain roller 21 and the roll roller 26 respectively. That is, when the call roller 25 is in contact with the ink fountain roller 21, the call roller 25 is separated from the roll roller 26. This reciprocation is also referred to as ink recall, and the greater the number of ink recalls, the greater the amount of ink supply. In addition, the ink fountain key K slides in the direction of the arrow S with respect to the ink fountain roller 21 so that the ink fountain key K can be moved in contact with and separated from it. And a large amount of ink is supplied. The ink fountain key K is moved by driving the ink fountain key drive motor M2 shown in FIG. Further, a water vessel 23 for containing dampening water is provided, and the dampening water in the water vessel 23 can be supplied to the printing plate through the water source roller 24 and the like.

  The doctor blade 22 is provided so as to be able to contact and separate one ink roller 4a of the ink roller group 4 (in FIG. 2, the ink roller positioned second from the bottom of the left end in FIG. It is done. The doctor blade 22 is rotated by the drive of a doctor drive air cylinder M3 shown in FIG. The doctor blade 22 is provided to extend in the axial direction of the ink roller 4a, and is configured to be able to scrape the ink supplied to the ink roller 4a when abutting on the ink roller 4a. Supply can be reduced quickly. For example, as shown in FIG. 4A, the reduction of the ink supply amount is performed when the ink density is higher than the target density (target ink density), and the ink on the ink roller 4a is scraped. By taking it, the target density (target ink density) is not exceeded. That is, the ink is scraped off so that the ink density is equal to or lower than the target density (target ink density).

  Specifically, as shown in FIG. 4A, the ink density of the shaded area in the six regions (K1, K4, K5, K6, Kn-3, Kn-2) is the target density (target ink density) It is higher than). Therefore, the doctor blade 22 is brought into contact with the ink roller 4a to scrape the ink. The prediction of the ink density after the scraping is shown in FIG. 4 (b). That is, in FIG. 4B, the portion surrounded by the two-dot chain line corresponds to the portion where the ink is scraped off. Also, in FIG. 4B, the amount of ink scraped off in the area corresponding to the first ink fountain key K1 from the left, where the ink density is higher than the target density (target ink density), is the second and third from the left. Naturally, the amount of ink scraped off in the region corresponding to the ink fountain key K2, K3 is larger, but the height of the ink left after being scraped off is higher for the ink fountain key K2, K3 than for the ink fountain key K1. It's getting lower. This is considered to be a state in which the ink having fluidity is in the state of being undulated in the circumferential direction on the ink roller 4a when the ink roller 4a is rotating. For this reason, the ink (the ink corresponding to the ink fountain key K2 and K3) which is not originally scraped off is also scraped off in contact with the doctor blade 22. As a result, the height of the ink scraped off may be lower for the ink fountain keys K2 and K3 than for the ink fountain key K1. The reason why the ink height of the fifth ink fountain key K5 from the left is the highest height corresponding to the target density (target ink density) is also the reason described above.

  Moreover, the ink density of the area | region corresponding to each ink fountain key after scraping off the ink shown in FIG.4 (b) is among the tables collectively produced based on the huge data obtained by repeating experiment actually. It can be grasped by taking out one data from. In FIG. 4B, the scraping amount of ink (a portion surrounded by a two-dot chain line) is displayed in a state in which the design factor of the image with respect to each ink fountain key is reflected. Also, by bringing the doctor blade 22 into contact with the ink roller 4a for a preset time or more, the height of the ink on the ink roller 4a can be equalized in the roller width direction, but the time In this case, the height of the ink density is not uniform in FIG. 4B because the time is set to a time shorter than the setting time at which the height of the ink becomes uniform.

  Moreover, as shown in FIG. 4, the ink fountain key K is provided with a plurality (K1 to Kn) in the axial direction of the ink fountain roller 21 (see FIG. 2). As shown in FIG. 4A, the distance (opening) of the ink fountain key K to the ink fountain roller 21 is determined for each ink fountain key by the necessary ink amount based on the area coverage of the printed image. The drawing rate is the number of dots to be printed relative to the total number of dots included in one page of the paper to be printed (the total number of dots to be printed and the number of dots not to be printed). For example, each area corresponding to each ink fountain key of printed matter For one of the tables in which a large number of design factor data are stored, one set of data is picked up and used. As the image rate data, a printed image serving as a sample or a printed image serving as a sample is created with a personal computer or the like, and the image rate for each area corresponding to each ink fountain key is determined from the captured or created image and used as data. It is

  FIG. 3 is a block diagram showing a configuration of a control device of the printing press. A read-only ROM and a readable / writable RAM are connected to the microprocessor 50, and are configured to output a drive control signal of the main motor M1 for driving the printing machine through the interface 51. Further, a GUI (Graphical User Interface) 30 is connected to the interface 51. The GUI can display various states of the printing press, and can also perform various operations using touch panel buttons. Further, the ink fountain key drive motor M2 and the doctor drive air cylinder M3 for swinging the doctor blade 22 are also connected. The present invention can be realized by using other control means such as a programmable logic device instead of the above-mentioned microprocessor. Although other devices are also connected to the interface 51, the present invention is not limited to the one shown in FIG. 3 because components not related to the present invention are omitted.

  An ink density adjustment method for controlling the printed matter to be printed by the control device to be a target ink density will be described based on a flowchart shown in FIG. When the operator presses a not-shown ink density adjustment button or switch or the like, control of adjusting the ink density based on an instruction signal from the control device is started. When control is started, the control device performs various processing based on the determination of the control device. First, the printer is driven to start trial printing of 50 sheets (the number of sheets can be freely changed) (step S1). The control device issues an instruction to measure the ink density of the 31st to the final 50th printed matter whose printing state is stabilized since the start by the sensor (not shown) provided in the printing machine. By measuring the printed matter in which the printing state is stable as described above, the variation of the measurement result can be suppressed. In practice, a plurality of ink densities in the width direction of the printed matter are measured by measuring the ink density of the color patch printed in the area corresponding to each ink fountain key of the printed printed matter. When the measurement of the ink density of all the printed matter (the printed matter from the 31st sheet to the 50th sheet) is finished, the automatic sheet feeding is stopped (the idling state which becomes lower than the speed at the printing time) and those measured. The ink density for each ink fountain key of the printed matter is averaged (step S2). As described above, by averaging a plurality of measured ink densities for each ink fountain key, it is possible to absorb a measurement error when measuring the ink density. Here, the ink density of the test printed matter is measured, but the ink density of the previously printed matter (data of the ink density measured at the time of the previous printing) may be used. In addition, although the ink density of the 31st to 50th final printed sheets on which the trial printing was performed is measured by a sensor (not shown) provided in the printing machine, the 31st to 50th final sheets are measured. It is also possible to extract some of the printed materials of the above and manually measure the ink density of the several printed materials that have been extracted.

  Subsequently, it is determined whether or not the averaged ink density is a preset allowable value (target ink density set within the allowable range between the upper limit value and the lower limit value of the target ink density) (step S3). If it is determined that the averaged ink density is the allowable value (target ink density), the process proceeds to the main printing (step S11). If it is determined that the averaged ink density is out of the allowable value, it is determined whether at least one of the ink densities is higher than the target ink density (step S4). If it is determined that at least one ink density is high (in FIG. 4A, it is determined that the ink in the six regions is higher than the target density (target ink density)), as described above, the ink roller The doctor blade 22 starts scraping the ink on 4a (step S5).

  After the scraping, it is determined whether the ink density is lower than the target ink density (step S6). If it is determined that the ink density is lower than the target ink density, the ink bulking amount is determined based on the density prediction of the ink after scraping shown in FIG. 4B (calculated or tabulated data Select one from the above to increase the volume of the ink (step S7). The bulking amount of this ink is obtained by first subtracting the current ink density (ink density of the ink which has been scraped off) from the target density (target ink density) to obtain a density difference, and the density difference and the printing schedule The amount of ink for each ink fountain key is determined by the area coverage corresponding to each ink fountain key of the printed matter. In addition, although the current ink density picks up the ink density in the table created based on the scraping time, it may be determined from the result of actually measuring the ink on the roller. Specifically, the amount of ink is determined by experiment from the relationship between the density difference and the drawing rate to obtain the amount of ink for reaching the target density, and the determined data is made into a table and stored and made into a table Although one of a large number of data is selected, the density difference and the drawing rate may be calculated by applying to a predetermined equation and calculating. Thus, the ink degree is determined by determining the opening degree of each of the ink fountain keys K1 to Kn based on the ink amount determined by the density difference between the target ink density and the current ink density and the print density of the print image to be printed. The amount of increasing the ink can be properly set (see FIG. 4C), and the time for matching the target ink density can be reliably shortened. FIG. 4 (d) shows the ink density after adding a certain amount of ink from FIG. 4 (b).

  When the bulking is completed, the printing press is accelerated from the idling speed to the printing speed, and the test printing is further performed on 50 sheets, and the ink density of the printed matter printed as described above is measured (step S8). This allows a final check of the ink density, but step S8 may optionally be skipped. Also in this case, the ink density of the 31st to the 50th final printed matter whose printing state is stabilized after the start of printing may be measured in the same manner as described above, and the ink density for each ink fountain key of the measured printed matter may be averaged . In addition, after the test printing of 50 sheets measured, the automatic sheet feeding is stopped in the same manner as described above (the idle state is set to be lower than the speed at the time of printing). It is judged whether the averaged ink density is a preset allowable value (target ink density) (step S9), and if it is judged that the ink density is out, whether the operator starts the main printing or the ink density again It is determined whether correction is to be performed (step S10). This may be a deviation of the ink density that does not cause a problem depending on the printed matter to be printed even if it is out, and the judgment is difficult to be made on the machine side, and is made to be made by the operator.

  As described above, when at least one of the measured ink densities is higher than the target ink density, the ink on the at least one roller (here, the ink roller 4a) is spread over the entire width of the roller Scrape. When all the measured ink densities are lower than the target ink density, the amount of ink supplied to the ink fountain roller 21 is increased. By performing these operations, the time until convergence to the target ink concentration can be suppressed, so generation of waste paper can be suppressed. Moreover, in the above embodiment, since the ink is converged to the target ink density in a state where printing of the printing press is stopped, generation of waste paper can be further suppressed.

  Further, according to the present invention, an ink fountain roller to which ink in the ink fountain is supplied, a plurality of ink fountain keys provided in the axial direction of the ink fountain roller, and a target ink set within an allowable range sandwiched by the upper limit and the lower limit. And an opening adjustment means (ink fountain key drive motor M2) for adjusting the opening degree of each of the plurality of ink fountain keys so as to adjust the amount of ink supplied from the inside of the ink fountain to the ink fountain roller so as to become the density. A printing machine configured to supply ink supplied to a roller to a plate cylinder on which a printing plate is wound via a large number of ink roller groups by the feeding operation of an ink feeding roller, wherein the previous printed matter or this time is Measuring means for measuring the ink density of the area corresponding to each ink fountain key of the printed matter printed by the trial printing before the final printing, and the measurement If at least one of the plurality of ink concentrations is higher than the target ink concentration, the ink on the at least one roller of the ink fountain roller, the ink feeding roller, and the ink roller group is A scraping means (doctor blade 22) for scraping across the full width of the roller, and when all the measured ink densities are lower than the target ink density, the opening degree of each ink fountain key is adjusted based on the target ink density The printing machine may be provided with an increasing unit for increasing the amount of ink supplied to the ink fountain roller.

  The present invention is not limited to the above embodiment, and various modifications can be made without departing from the scope of the present invention.

  The above-described embodiment is a sheet-fed offset printing press, but the printing press is not limited thereto as long as the ink supply amount can be adjusted, and can be applied to other printing presses such as a rotary offset printing press.

  In the embodiment described above, the ink of the ink roller 4a positioned second from the bottom of the left end of the ink roller group 4 is scraped off, but another ink roller or ink fountain roller of the ink roller group 4 is used 21 or a configuration in which the ink of the ink feeding roller 25 is scraped off.

  In the above-described embodiment, the ink on one ink roller 4a is scraped off, but the ink on two or more arbitrary number of ink rollers may be scraped off.

  DESCRIPTION OF SYMBOLS 1 ... Plate cylinder, 2 ... Rubber cylinder, 3 ... Pressure cylinder, 4 ... Ink roller group, 4a ... Ink roller, 5 ... Printing unit, 6 ... Delivery cylinder, 7 ... Feed cylinder, 8 ... Feeder board, 9 ... Port Plates 10: swing arms 11, 11: first delivery cylinders, 12: second delivery cylinders, 13, 14: sprockets, 15: chains, 16: varnish plate cylinders, 21: ink fountain rollers, 22: doctor blades, Reference Signs List 23 water boat, 24 water source roller, 25 ink call roller, 26 rollover roller, 50 microprocessor, 51 interface, A sheet feeding portion B printing portion C surface processing portion D Paper discharge unit, K, K1 to Kn: ink fountain key, M1: main machine motor, M2: ink fountain key drive motor, M3: doctor drive air cylinder, S, T: arrow

Claims (4)

Adjust the amount of ink supplied from the inside of the ink fountain to the ink fountain roller by adjusting the opening degree of each of the plurality of ink fountain keys so that the target ink density is set within the allowable range between the upper limit and the lower limit. And a method for adjusting the ink density of a printing press configured to supply the ink supplied to the ink fountain roller to the plate cylinder on which the printing plate is wound via a large number of ink roller groups by the call-up operation of the ink feed roller. And
The ink density of the area corresponding to each ink fountain key of the previous printed matter or the printed matter printed by the trial printing before the current main printing is measured, and at least one of the plurality of measured ink densities is the target ink density If higher, the ink on at least one of the ink fountain roller, the ink feeding roller, and the ink roller group is scraped over the entire width of the roller, and all the ink densities measured are When the ink density is lower than the target ink density, the opening degree of each ink fountain key is adjusted based on the target ink density to increase the amount of ink supplied to the ink fountain roller. Ink density adjustment method in a printing press.   The opening degree of each ink fountain key is determined based on the ink amount determined by the density difference between the current ink density and the target ink density after scraping the ink on the at least one roller and the print area rate of the print image to be printed 2. The method according to claim 1, wherein the amount of ink determined and supplied to the ink fountain roller is increased.   When all the measured ink densities are lower than the target ink density, the ink fountain key of each ink fountain key is calculated based on the density difference between the target ink density and the current ink density and the print area rate of the print image to be printed. The method according to claim 1 or 2, wherein the opening degree is determined to increase the amount of ink supplied to the ink fountain roller.   The ink density of the area corresponding to each ink fountain key of each of a plurality of printed materials from a predetermined number of sheets to a predetermined number of sheets set in advance among the plurality of printed materials printed by the test printing is measured, and the measured ink density is 4. The high or low level with respect to the target ink density is determined by averaging for each ink fountain key and comparing the averaged ink density with the target ink density, according to any one of claims 1 to 3. Ink density adjustment method in a printing press.

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