JP7025921B2 - How to increase the bulk of ink in a printing machine - Google Patents

Description

The present invention relates to a method for increasing the bulk of ink in a printing machine configured to have a target ink density.

In such a printing machine, the amount of ink supplied to the ink fountain roller from inside the ink fountain is adjusted by adjusting the opening degree of each of the plurality of ink fountain keys, and the ink supplied to the ink fountain roller is called up by the ink calling roller. The printing plate is supplied to the wound plate cylinder via a large number of ink rollers, and the ink is transferred from the plate cylinder to the impression cylinder via the rubber cylinder to print the printed matter.

By the way, the ink density of the printed matter printed this time is due to changes in the fluidity of the ink due to differences in humidity and temperature during printing, and the difference between the image of the printed matter printed last time and the image of the printed matter scheduled to be printed this time. May be lower than the target ink density. To solve this problem, a predetermined number of test prints are performed before the main printing, the ink density of the predetermined printed matter is measured, and the measured value is sandwiched between the upper limit value and the lower limit value (target). If it is not in the ink density), adjust the opening of the ink fountain key until the ink density of the printed matter is within the allowable range. Then, even if the number of printed matter exceeds a predetermined number, if the measured value is not within the permissible range, a printing machine for stopping printing is already known (for example, Patent Document 1).

Japanese Patent No. 6214862

In the configuration of Patent Document 1, there is an inconvenience that waste paper increases because the printed matter is being printed even while the opening degree of the ink fountain key is adjusted until the ink density of the printed matter falls within the allowable range. .. In particular, since the printing press has a large number of ink rollers, each of these many ink rollers has ink, so that the thickness (concentration) of the ink on all the ink rollers can be immediately determined. Cannot be changed. Therefore, it takes a lot of time for the ink density of the printed matter to reach the allowable range, which increases the amount of wasted paper as described above.

The present invention has been made to solve such a problem, and an object of the present invention is to provide a method for increasing the bulk of ink in a printing machine capable of suppressing waste paper and matching the ink density with a target density. Is.

In order to achieve the above object, in the method for increasing the bulk of ink in the printing machine according to the present invention, the current ink density in the region corresponding to all the ink spot keys of the printed matter corresponds to the target ink density of the printed matter to be printed this time. When it is lower than This is a method for increasing the bulk of ink in a printing machine configured to increase the bulk of ink by supplying the plate to a wound plate cylinder, and the increase in ink is performed in a state where printing is stopped. The amount of bulkiness of the ink is determined from the difference in density between the target ink density and the current ink density and the image ratio of the printed image to be printed, and the opening degree of each ink pot key is determined based on the bulkiness. It is characterized by determining and increasing the bulk of the ink.

According to the above configuration, when the current ink density of the area corresponding to all the ink spot keys of the printed matter is lower than the target ink density of the printed matter to be printed this time, the printing is stopped and the target ink is applied. The bulkiness of the ink is determined from the density difference between the density and the current ink density and the image ratio of the printed image to be printed, and the opening degree of each ink pot key is determined based on the bulkiness to increase the bulk of the ink. By doing so, the amount of ink on the rollers can be adjusted quickly, so waste paper can be suppressed.

Further, in the method for increasing the bulk of ink in the printing machine according to the present invention, it is preferable that the target ink density is an ink density set to the same value in each region.

Further, in the method for increasing the bulk of ink in the printing machine according to the present invention, a plurality of printed matter is printed by trial printing before the main printing, and among the plurality of printed matter, a predetermined predetermined sheet to the final sheet is set in advance. The target is to measure the ink density in the area corresponding to each ink pot key of each of the multiple printed matter up to the eyes, average the measured ink density for each ink pot key, and compare the averaged ink density with the target ink density. It may be determined whether it is lower than the ink density.

As described above, it is possible to suppress variations in measurement results by measuring the ink densities of a plurality of printed matter from a predetermined predetermined sheet to the final sheet, which are set in advance so that the printing machine is driven and the printing state is easily stabilized. Can be done. Further, by averaging a plurality of measured ink densities for each ink pot key, it is possible to absorb a measurement error at the time of measuring the ink densities. Therefore, it is possible to prevent the difference between the ink density and the target ink density from being significantly deviated from the true value.

According to the present invention, after printing is stopped, the bulkiness of the ink is determined from the density difference between the target ink density and the current ink density and the image area ratio of the printed image to be printed, and the bulkiness is determined based on the bulkiness. By determining the opening degree of each ink fog key and increasing the bulk of the ink, it is possible to provide a method of increasing the bulk of the ink in a printing machine capable of suppressing waste paper and matching the ink density with the target density. ..

It is a schematic vertical sectional side view of a printing machine. It is an enlarged view of the ink supply part of a printing machine. It is a block diagram of the control device which controls a printing machine. (A) is an explanatory diagram showing the measured values obtained by measuring the ink density in each ink pot key, (b) is an explanatory diagram showing the ink density when the ink is scraped from (a), and (c) is the ink from (b). Is an explanatory diagram showing the ink density after adding the image ratio in consideration of the image ratio, and (d) is an explanatory diagram showing the ink density after adding a certain amount of ink from (b). It is a flowchart which shows the ink adjustment method.

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

FIG. 1 is a printing machine provided with a base ink adjustment mode, and shows a sheet-fed offset printing machine (hereinafter, simply referred to as a printing machine). This printing machine prints on a paper feed unit A for feeding sheet sheets as printing paper one by one from a paper stacking table by a feeder device, a paper separator, etc., and a sheet sheet paper from this paper feed unit A. It is provided with a printing unit B for performing this, a surface processing unit C for performing surface treatment on the sheet of paper printed by the printing unit B, and a paper ejection unit D for ejecting the sheet of paper. Here, the printing unit B is a printing unit B provided with four printing units 5 so that four colors can be printed, but colors other than the four colors, that is, one color, two colors, three colors, or five colors. It may be a printing unit capable of performing the above printing. Further, the specific configuration of each part constituting the printing machine is not limited to that shown in FIG.

The printing unit 5 includes a plate cylinder 1, a rubber 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 sent out sheet paper between the claw stand and the claw. I have. Reference numeral 7 is a paper feed cylinder, which serves to receive the sheet of paper conveyed on the feeder board 8 and the mouth plate 9 from the swing arm 10 and pass it to the impression cylinder 3. The paper feed cylinder 7 and the swing arm 10 are also provided with the above-mentioned claw base and claws. Further, a printing plate (not shown) on which an image is formed is wound and fixed to the plate cylinder 1.

The paper ejection unit D is composed of a chain transfer device including two paper ejection cylinders and a gripper. That is, a first paper ejection cylinder 11 adjacent to the impression cylinder 3 of the surface treatment unit C and a second paper ejection cylinder 12 adjacent thereto are provided, and are provided on the front side (upstream side) of the sheet of paper in the transport direction. An endless chain 15 is wound around the sprocket 13 and the sprocket 14 provided on the rear side (downstream side) of the sheet in the transport direction, and the rotation of the sprocket 13 and 14 regulates the chain guide (not shown). The chain 15 orbits in this state. The sheet-fed paper is gripped by a chain gripper (not shown) fixed to the chain 15 at predetermined intervals and discharged.

As shown in FIG. 1, the surface treatment portion C is provided with a varnish plate cylinder 16 that faces and abuts the impression cylinder 3. Further, although not shown, an anilox roller that comes into contact with the varnish plate cylinder 16 to supply varnish is provided. The surface treatment unit C is provided with a body elevating device (not shown) that supports the varnish plate body 16 so as to be able to move up and down with respect to the impression cylinder 3.

FIG. 2 is an enlarged view of the ink supply unit. The ink pot roller 21 to which the ink in the ink pot is supplied rotates counterclockwise in the drawing, and supplies ink to a large number of ink roller groups 4 located downstream via the ink calling roller 25. Although the ink calling roller 25 is not shown in detail, it reciprocates to the ink pot roller 21 and the rollover roller 26 so that they can be brought into contact with each other. That is, when the calling roller 25 is in contact with the ink pot roller 21, the calling roller 25 is separated from the rollover roller 26. This reciprocating motion is also called ink calling, and the larger the number of ink callings, the larger the amount of ink supplied. Further, the ink acupoint key K can be brought into contact with and detached from the ink acupoint roller 21 by sliding in the direction of the arrow S, and the more the ink acupoint key K is separated from the ink acupoint roller 21, the larger the opening degree of the ink acupoint key K. It is configured to supply a large amount of ink. The ink pot key K is moved by driving the ink pot key drive motor M2 shown in FIG. Further, a water vessel 23 for accommodating the dampening water is provided, and the dampening water in the water vessel 23 can be supplied to the printing plate via the water source roller 24 or the like.

One of the ink rollers 4 is provided on the ink roller 4a (the ink roller located second from the bottom on the left end in FIG. 2) so that the doctor blade 22 can be brought into contact with and detached by rotating in the direction of the arrow T. Has been done. The doctor blade 22 is rotated by driving the doctor drive air cylinder M3 shown in FIG. The doctor blade 22 is provided so as to extend in the axial direction of the ink roller 4a, and is configured to be able to scrape off the ink supplied to the ink roller 4a when it comes into contact with the ink roller 4a. The supply amount can be reduced quickly. For example, as shown in FIG. 4A, the amount of ink supplied is reduced when the ink density exceeds (exceeds) the target density (target ink density), and the ink on the ink roller 4a is scratched. By taking it, the target density (target ink density) is not exceeded. That is, the ink is scraped so that the ink density is equal to or lower than the target density (target ink density). The target ink density is an ink density set to the same value in each region, and the bulking described later is performed so that the target ink density has the same value in each region.

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). ) Is higher than that. 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 being scraped off 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 has been scraped off. Further, in FIG. 4B, the amount of ink scraped off in the region corresponding to the first ink pot key K1 from the left, whose ink density is higher than the target density (target ink density), is the second and third from the left. It is natural that the amount of ink scraped off in the area corresponding to the ink pot keys K2 and K3 is larger, but the height of the ink remaining scraped off is higher in the ink pot keys K2 and K3 than in the ink pot keys K1. It's getting low. It is considered that this is because when the ink roller 4a is rotating, the fluid ink is in a state of waving on the ink roller 4a in the circumferential direction. For this reason, ink that is not originally scraped off (ink in the region corresponding to the ink pot keys K2 and K3) is also scraped off in contact with the doctor blade 22. As a result, the height of the ink remaining after being scraped off may be lower in the ink pot keys K2 and K3 than in the ink pot keys K1. It should be noted that the height of the ink of the fifth ink pot key K5 from the left is the highest height that matches the target density (target ink density) for the above-mentioned reason.

In addition, the ink density in the area corresponding to each ink pot key after scraping the ink shown in FIG. 4 (b) is in a table created by aggregating based on a huge amount of data obtained by actually repeating the experiment. It can be grasped by extracting one data from. In FIG. 4B, the amount of ink scraped off (the portion surrounded by the alternate long and short dash line) is displayed in a state where the image magnification of the image for each ink point key is reflected. Further, by bringing the doctor blade 22 into contact with the ink roller 4a for a preset time or longer, the height of the ink on the ink roller 4a can be equalized to the same height in the roller width direction. Therefore, since the time is set shorter than the set time at which the height of the ink becomes uniform, the height of the ink density is not uniform in FIG. 4B.

Further, as shown in FIG. 4, a plurality of ink acupoint keys K (K1 to Kn) are provided in the axial direction of the ink acupoint roller 21 (see FIG. 2). As shown in FIG. 4A, the distance (opening) of the ink acupoint key K with respect to the ink acupoint roller 21 is determined for each ink acupoint key according to the required amount of ink based on the image ratio of the printed image. The image ratio is the number of dots to be printed with respect 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). One data is picked up and used from the table in which a large number of image ratio data are stored. The image ratio data is obtained by capturing a sample printed matter or creating a sample print image on a personal computer or the like, and obtaining the image ratio for each region corresponding to each ink pot key from the captured or created images. It was done.

FIG. 3 is a block diagram showing a configuration of a control device of a printing machine. A read-only ROM and a read / write RAM are connected to the microprocessor 50, and are configured to output a drive control signal of the machine motor M1 that drives the printing machine via the interface 51. Further, a GUI (Graphical User Interface) 30 that can display various states of the printing machine and can perform various operations by touch panel type buttons is connected to the interface 51. Further, the above-mentioned ink pot key drive motor M2 and a 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. Further, although other devices are also connected to the interface 51, those not related to the present invention are omitted, so that the present invention is not limited to the one shown in FIG.

An ink density adjusting method for controlling the printed matter printed by the control device so as to have a target ink density will be described with reference to the flowchart shown in FIG. When the operator presses a button or switch for adjusting the ink density (not shown), the control for adjusting the ink density is started based on the instruction signal from the control device. When the control is started, the control device causes the control device to perform various processes based on the judgment of the control device. First, the printing machine 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 printed matter from the 31st sheet to the final 50th sheet, in which the printing state is stable from the start, by a sensor (not shown) provided in the printing machine. By measuring the printed matter whose printed state is stable in this way, it is possible to suppress variations in the measurement results. Actually, a plurality of ink densities in the width direction of the printed matter are measured by measuring the ink densities of the color patches printed in the area corresponding to each ink pot key of the printed matter. When the measurement of the ink density of all printed matter (printed matter from the 31st sheet to the 50th sheet) is completed, the automatic paper feeding is stopped (the idling state where the speed becomes slower than the printing speed (printing by the printing machine is stopped). In addition to the state), the ink densities of each of the measured ink pot keys of the printed matter are averaged (step S2). By averaging the plurality of measured ink densities for each ink pot key in this way, it is possible to absorb the measurement error at the time of measuring the ink densities. Here, the ink density of the printed matter printed on the trial print is measured, but the ink density of the printed matter printed last time (data of the ink density measured at the time of the previous printing) may be used. Here, the ink densities of the printed matter from the 31st sheet to the final 50th sheet after the test printing are measured by a sensor (not shown) provided in the printing machine, but the 31st sheet to the final 50th sheet are measured. You may extract some of the printed matter up to the above and manually measure the ink density of the extracted several printed matter.

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

After the scraping is completed, it is determined whether the ink density is lower than the target ink density (step S6). When it is determined that the ink density is lower than the target ink density, the bulkiness of the ink is calculated (calculated or tabulated) based on the ink density prediction after scraping shown in FIG. 4 (b). (Select one from among them) to increase the bulk of the ink (step S7). To determine the bulkiness of this ink, first, the current ink density (ink density of the ink remaining scraped off) is subtracted from the target density (target ink density) to obtain the density difference, and the density difference and the printing schedule are planned. The amount of ink (the amount of increase in ink volume) for each ink pot key is determined by the image ratio corresponding to each ink pot key of the printed matter. The current ink density is determined by picking up the ink density in the table created based on the scraping time, but it may be calculated from the result of actually measuring the ink on the roller. To determine the amount of ink, specifically, the amount of ink for reaching the target density was obtained by an experiment from the relationship between the density difference and the image ratio, and the obtained data was stored in a table and stored in a table. One is selected from a large number of data, but the density difference and the image ratio may be applied to a predetermined mathematical formula and calculated by calculation. In this way, the ink by determining the opening degree of each ink pot key K1 to Kn based on the amount of ink determined by the difference in density between the target ink density and the current ink density and the image area ratio of the printed image to be printed. The amount of ink to be increased (the amount of ink to be increased) can be appropriately set (see FIG. 4C), and the time required to match the target ink density can be reliably shortened. Here, the bulk is increased after scraping, but the current ink density of the region corresponding to each of the plurality of ink fountain keys of the printed matter is assigned to each of the regions in the current printing without scraping. When the ink density of the printed matter is lower than the target ink density, the bulk may be increased so that the current ink density becomes the target ink density. FIG. 4D shows the ink density after adding a certain amount of ink from FIG. 4B.

When the bulking is completed, the printing machine is speeded up from the idling speed to the printing speed, 50 sheets of test printing are performed, and the ink density of the printed matter printed in the same manner is measured (step S8). This allows the final check of the ink density to be performed, but step S8 may be skipped in some cases. In this case as well, the ink density of the printed matter from the 31st sheet to the final 50th sheet, in which the printed state is stable after the start of printing, may be measured and the ink density of each ink pot key of the measured printed matter may be averaged. .. Further, after the measured 50-sheet test print is performed, the automatic paper feeding is stopped as described above (the idling state is set to be lower than the printing speed). It is determined whether or not the averaged ink density is a preset allowable value (target ink density) (step S9), and if it is determined that the averaged ink density is out of line, the operator either starts the main printing or determines the ink density again. It is determined whether to perform the correction (step S10). Even if it is off, the ink density may be off to the extent that it does not matter depending on the printed matter to be printed, and it is difficult for the machine to make the judgment, so the operator is made to judge it.

As described above, when at least one of the measured ink densities is higher than the target ink densities, the ink on at least one roller (here, the ink roller 4a) is applied over the entire width of the rollers. Ink and scrape. If all the measured ink densities are lower than the target ink densities, the amount of ink supplied to the ink fountain roller 21 is increased. By doing these, the amount of ink on the roller can be adjusted quickly, so waste paper can be suppressed. Moreover, in the above-described embodiment, since the printing of the printing machine is stopped and the ink density is converged to the target ink density, the generation of waste paper can be further suppressed.

Further, in the present invention, the ink pot roller to which the ink in the ink pot is supplied, a plurality of ink pot keys provided in the axial direction of the ink pot roller, and the target ink set in the allowable range sandwiched between the upper limit value and the lower limit value. The ink pot is provided with an opening adjusting means (ink pot key drive motor M2) for adjusting the opening degree of each of the plurality of ink pot keys so as to adjust the amount of ink supplied from the ink pot to the ink pot roller so as to have a density. It is a printing machine configured to supply the ink supplied to the rollers to the plate cylinder around which the printing plate is wound via a large number of ink roller groups by the calling operation of the ink calling roller, and is the previous printed matter or this time. A measuring means for measuring the ink density in the region corresponding to each ink pot key of the printed matter printed by the test printing before the main printing, and at least one of the measured ink densities is higher than the target ink densities. When it is high, the ink pot roller, the ink calling roller, the scraping means (doctor blade 22) for scraping the ink on at least one roller of the ink roller group over the entire width of the roller, and the measurement. When all the ink densities are lower than the target ink density, the ink pot key is provided with an increase means for increasing the amount of ink supplied to the ink pot roller by adjusting the opening degree of each ink pot key based on the target ink density. It may be a printing machine characterized by the fact that the ink is printed.

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

In the above-described embodiment, the sheet-fed offset printing press is used, but the printing press is not limited to this 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.

Further, in the above-described embodiment, the ink of the ink roller 4a located second from the bottom of the left end of the ink roller group 4 is scraped off, but other ink rollers or ink pot rollers of the ink roller group 4 are scraped off. The structure may be such that the ink of the 21 or the ink calling roller 25 is scraped off.

1 ... plate cylinder, 2 ... rubber cylinder, 3 ... impression cylinder, 4 ... ink roller group, 4a ... ink roller, 5 ... printing unit, 6 ... transfer cylinder, 7 ... paper feed cylinder, 8 ... feeder board, 9 ... mouth Plate, 10 ... Swing arm, 11 ... 1st paper discharge cylinder, 12 ... 2nd paper discharge cylinder, 13, 14 ... Sprocket, 15 ... Chain, 16 ... Niss plate cylinder, 21 ... Ink pot roller, 22 ... Doctor blade, 23 ... Watercraft, 24 ... Water source roller, 25 ... Ink calling roller, 26 ... Rolling roller, 50 ... Microprocessor, 51 ... Interface, A ... Paper feeding unit, B ... Printing unit, C ... Surface processing unit, D ... Paper ejection unit, K, K1 to Kn ... Ink pot key, M1 ... Machine motor, M2 ... Ink pot key drive motor, M3 ... Doctor drive air cylinder, S, T ... Arrow

Claims (1)

Before the main printing, a plurality of printed matter is printed by test printing, and among the plurality of printed matter, the ink in the area corresponding to each ink pot key of each of the plurality of printed matter from the predetermined predetermined sheet to the final sheet set in advance. When the density is measured, the measured ink densities are averaged for each ink pot key, and the averaged ink densities are compared with the target ink densities to determine whether they are lower than the target ink densities. In addition , the printing plate is wound by adjusting 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 averaged ink density becomes the target ink density. It is configured to increase the bulk of the ink by supplying it to the rotated plate cylinder .
The bulk of the ink is increased while printing by the printing machine is stopped, and the bulk of the ink is increased by the density difference between the target ink density and the averaged ink density and the image area ratio of the printed image to be printed. A method for increasing the bulk of ink in a printing machine, which comprises indexing and determining the opening degree of each ink pot key based on the amount of the increase in bulk to increase the bulk of the ink.

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