JP2022065991A - Ink key aperture adjustment system of printer - Google Patents

Abstract

To provide an ink key aperture adjustment system of a printer which can suppress the occurrence of spoilage by preventing the excess of the printing density in an image region at a low image area ratio.SOLUTION: An ink key aperture adjustment system of a printer comprises: data acquisition means 8 which acquires aperture data in the OK sheet printing of an ink key corresponding to a low image area ratio whose image area ratio set in the image region obtained by dividing a print image is lower than a prescribed value; correlation derivation means 9 which derives a correlation between the low image area ratio and the aperture of the ink key on the basis of the aperture data of the ink key acquired by the data acquisition means 8; and correction means 10 which performs correction by multiplying the correlation derived by the correlation derivation means 9 by a coefficient that decreases the aperture of the ink key.SELECTED DRAWING: Figure 8

Description

The present invention relates to an ink key opening adjustment system for a printing press.

In the conventional printing machine, the opening degree of a plurality of ink keys provided in the ink pot is set (preset) according to the pattern to be printed before printing. The opening degree of each ink key is set by using the image area ratio in the area of each ink key of the pattern to be printed and the conversion curve showing the correlation between the image area ratio stored in advance and the opening degree of the ink key. .. In the area of the ink key where the color tone (particularly the print density) of the printed matter is inappropriate in printing with the set opening of the ink key, the opening of the ink key is adjusted to match the color tone with the target value.

Further, in a conventional printing machine, information on the opening degree of the ink key and the image area ratio of the area of the ink key in a state where the color tone of the printed matter matches the target value (when printing an OK sheet) is acquired, and based on the information. You can create a new conversion curve. The new conversion curve created in this way becomes more suitable, and it is said that the color tone matches earlier when used for later printing (see, for example, Patent Document 1).

However, in an image area having a low image area ratio (low image area ratio) in a printed image, the color tone of the printed image may not match even if preset using the above new conversion curve due to various factors. be. In particular, when the print density exceeds the permissible range in an image area with a low image area ratio, a large amount of paper is required to reduce the print density to the permissible range by printing, so that waste paper is extremely wasteful. The inconvenience of increasing the number of prints occurs.

Japanese Patent No. 4395287

The present invention has been made to solve such a problem, and an object of the present invention is to prevent an excess of print density in an image area having a low image area ratio and suppress the occurrence of waste paper. It is to provide an ink key opening adjustment system.

In order to achieve the above object, the ink key opening adjustment system of the printing machine according to the present invention accepts an ink key corresponding to a low image area ratio in which the image area ratio set in the image area in which the printed image is divided is lower than a predetermined value. Correlation that derives the correlation between the low image area ratio and the opening degree of the ink key based on the data acquisition means for acquiring the opening degree data at the time of sheet printing and the opening degree data of the ink key acquired by the data acquisition means. It is characterized by including a derivation means and a correction means for correcting the correlation derived by the correlation derivation means by multiplying the correlation by a coefficient for reducing the opening degree of the ink key.

According to the above configuration, the correlation derived by the correlation deriving means is corrected by multiplying the correlation derived by the correlation deriving means by a coefficient for reducing the opening degree of the ink key, so that the ink key corresponding to the image area in which the low image area ratio in the printing machine is set is corrected. The opening can be kept small. Therefore, in the printing machine in which the opening degree of the ink key is adjusted by using the system of the present invention, the print density value in the image area in which the low image area ratio is set can be set to a value lower than the target value, and printing can be performed. Printing for lowering the density value can be suppressed.

Further, in the ink key opening degree adjusting system of the printing machine according to the present invention, the coefficient is set for each section area in which the image area ratio is subdivided into each value in a predetermined range, and the coefficient is set for each section area. It may be set so that the larger the image area ratio is, the larger the image area ratio is.

As described above, a coefficient is set for each section area in which the image area ratio is subdivided for each value in a predetermined range, and the coefficient is set so that the larger the image area ratio of the section area is, the lower the coefficient is. It is possible to make the deviation of the density difference between the print density value and the target value in the image area of the image area ratio smaller.

Further, the ink amount correction method of the printing machine according to the present invention is used when printing an OK sheet of an ink key corresponding to an image area having a low image area ratio in which the image area ratio set in the image area in which the printed image is divided is lower than a predetermined value. A data acquisition step for acquiring the opening degree data of the above, and a correlation derivation step for deriving a correlation between the low image area ratio and the opening degree of the ink key based on the opening degree data of the ink key acquired in the data acquisition step. It is characterized by comprising a correction step of multiplying the correlation derived by the correlation derivation means by a coefficient for reducing the opening degree of the ink key to correct the correlation.

According to the above configuration, the correlation derived in the correlation derivation step is corrected by multiplying the correlation derived in the correlation derivation step by a coefficient for reducing the opening degree of the ink key. The opening can be kept small. Therefore, in the printing machine in which the opening degree of the ink key is adjusted by using the system of the present invention, the print density value in the image area in which the low image area ratio is set can be set to a value lower than the target value, and printing can be performed. Printing for lowering the density value can be suppressed.

According to the present invention, it is possible to prevent the print density value from being exceeded in an image area having a low image area ratio by correcting the correlation derived by the correlation deriving means by multiplying it by a coefficient for reducing the opening degree of the ink key. can. Thereby, it is possible to provide an ink key opening degree adjusting system of a printing machine capable of suppressing the occurrence of waste paper even in a printed matter having an image area having a low image area ratio.

It is a schematic side view of the ink supply part of a printing machine. The main flowchart which corrects the ink amount of a printing machine is shown. It is a sub-flow chart which shows the 2nd curve creation. It is a sub-flow chart which shows the processing after the 2nd curve creation. It is a graph which shows the ink key opening drawn by the approximate curve obtained by the least squares method. It is a graph which shows the ink key opening drawn by using the point of a curve based on the section where the plot is insufficient. It is a graph which shows the ink key opening which was drawn without using the point of the base curve in the section where the plot is insufficient. It is a control block diagram which concerns on this invention.

Hereinafter, the ink key opening adjustment system of the printing machine according to the embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows an ink supply unit provided inside a printing unit that prints on a printing machine.

In FIG. 1, the ink pot roller 1 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 3 located downstream via the ink calling roller 2. .. Although not shown in detail, the ink calling roller 2 reciprocates with respect to the ink pot roller 1 and the rollover roller 4 so as to be in contact with each other. That is, when the ink calling roller 2 is in contact with the ink pot roller 1, the ink calling roller 2 is separated from the rollover roller 4. This reciprocating motion is also referred to as an ink recalling operation, and the larger the number of ink recalling operations, the larger the amount of ink supplied to the ink roller group 3. Further, the ink key K provided in the ink pot slides with respect to the ink pot roller 1 in the direction of the arrow S so that the ink key K can be brought into contact with and separated from the ink pot roller 1. It is configured so that a large amount of ink is supplied onto the ink fountain roller 1 in an increased degree. Each ink key K is moved by driving an ink key drive motor (not shown). Further, a water boat 5 for accommodating dampening water is provided in the water portion located below the ink roller group 3, and a printing plate wound around the plate cylinder 7 via the water source roller 6 (shown in the figure). It is possible to supply the dampening water in the water boat 5 to the water boat 5.

A plurality of the ink keys K are arranged side by side in the axial direction of the ink pot roller 1 (see FIG. 1), that is, in the width direction (direction orthogonal to the transport direction) of the printing machine (printed matter). The distance (opening) of the ink key K with respect to the ink acupoint roller 1 is determined for each ink key according to the required amount of ink based on the printed image. The printed image has a plurality of image regions divided into a plurality of regions corresponding to each of the plurality of ink keys K arranged in the width direction of the printing machine. An image area ratio is set for each image area, and in the present invention, it corresponds to a low image area ratio in an image region in which a low image area ratio lower than a predetermined area ratio is set among the image area ratios. The opening degree data of the ink key K will be acquired by the data acquisition means 8 described later.

Then, the opening degree of the ink key K provided in the ink pot is set according to the pattern to be printed before printing (preset). The opening degree of each ink key K is a conversion curve (original curve) showing the relationship between the image area ratio in the area of each ink key K of the pattern to be printed, the image area ratio stored in advance, and the opening degree of the ink key K. , Is set using. In printing with the set opening of the ink key K, the color tone (particularly the print density) of the printed matter is measured by an in-line or offline measuring means. In the region of the ink key K where the color tone (particularly the print density) of the printed matter is inappropriate, the opening degree of the ink key K is adjusted to adjust the color tone to the target value (center value in the allowable range and its vicinity).

Information on the opening degree of the ink key K and the image area ratio of the area of the ink key K in a state where the color tone of the printed matter matches the target value (when printing an OK sheet) is acquired, and a new curve is obtained based on the information. Create one curve.

Even if preset printing is performed based on the first curve, the color tone of the printed image may not match in the image area having a low image area ratio due to various factors. In particular, when the print density exceeds the permissible range in an image area with a low image area ratio, a large amount of paper is required to reduce the print density to the permissible range by printing, so that waste paper is extremely wasteful. The inconvenience of increasing the number of prints occurs. Therefore, in the present invention, a new second curve is created in order to improve the accuracy in the image region having a low image area ratio.

In order to create the second curve, the three means shown in FIG. 8 are provided. That is, the data acquisition means 8 for acquiring the opening degree data of the ink key K corresponding to the image area having a low image area ratio lower than the predetermined value at the time of printing the OK sheet, and the ink key K acquired by the data acquisition means 8. The opening degree of the ink key K is reduced to the correlation deriving means 9 for deriving the correlation between the low image area ratio and the opening degree of the ink key K based on the opening degree data of the above, and the correlation derived by the correlation deriving means 9. The control unit 11 is provided with a correction means 10 for correcting by multiplying the coefficient. The correlation indicates a change in the value of the opening degree of the ink key K when the value of the low image area ratio gradually increases. This correlation is shown by a line graph as shown in FIGS. 6 and 7, but may be shown by a bar graph or by a table showing the change in the opening value of the ink key K in a table. good.

The process of actually creating the second curve by correcting the ink amount of the printing machine will be described with reference to the flowcharts of FIGS. 2 to 4.

First, in addition to the opening data of the ink key K corresponding to the image area of the low image area ratio (for example, the image area ratio is 0% to 20%) acquired by the data acquisition means 8, the medium image area ratio (for example, the image area ratio). The opening data of the ink key K corresponding to the image area of 21% to 50%) and the opening data of the ink key K corresponding to the image area having a high image area ratio (image area ratio is 51% to 100%). The data is acquired by the acquisition means (the data acquisition means may be the same as the data acquisition means 8 or may be composed of different means). After the data is acquired, as shown in FIG. 2, the plot in which the opening degree of the ink key, which is inappropriate data, is 0 is removed from the acquired data (step S1). Subsequently, the outliers are removed (step S2). This outlier is a plot in which the average and standard deviation of the opening degree of the ink key K in the area ratio of each region is obtained, and the difference from the average is twice or more the standard deviation.

After performing the above two removal processes, the second curve is created (step S3). In the creation of the second curve, as shown in FIG. 3, it is determined whether the number of plots in the section is equal to or greater than the set number or less than the set number (step S10), and it is determined that the number of plots is equal to or greater than the set number in all the sections. If it is determined, it is determined whether or not there is a previous section point (step S11). If there is a previous interval point, an approximate straight line passing through the boundary point with the previous interval is derived using the least squares method (step S12). If there is no previous interval point, an approximate straight line is derived using the least squares method (step S13).

Here, when there are a plurality of types of plot area ratios in the section (for example, 5 types when the image area ratio in FIG. 5 is between 40% and 60%), the plots in the section are plotted using the least squares method. Find an approximate straight line. The opening degree of the ink key K at the area ratio of the boundary of the section is calculated from the obtained approximate straight line and recorded as a point of the second curve. If there is only one type of plot area ratio in the section, the straight line to be obtained will be vertical (the denominator of the slope is 0) if the least squares method is used, so the plot of the previous section is also included. Find the straight line by performing the least squares method. Even if the plot of the previous section is included, if the slope of the straight line is vertical (or a straight line close to vertical), the section is widened until the slope of the straight line changes, and the least squares method is performed. If it still does not change, perform the least squares method including the plot of the later section.

In FIG. 5, the section where the image area ratio is 0% to 2% and the section where the image area ratio is 40% to 60% are approximate straight lines obtained by the least squares method because there are no points in the previous section. In addition, the image area ratio is 2% to 4%, 4% to 8%, 8% to 12%, 12% to 16%, 16% to 20%, 60% to 80. The% section and the 80% to 100% section are approximate straight lines that pass through the boundary with the previous section because there is a point in the previous section. In FIG. 5, since there is no plot in the section where the image area ratio is 20% to 40%, the point where the image area ratio is 20% and the point where the image area ratio is 40% are connected. In FIG. 5, the approximate straight line of the plot in the section is obtained by using the least squares method, and the first curve 1R showing the opening degree of the ink key K with respect to the image area ratio is shown. This first curve 1R is a curve before correction by a coefficient described later.

The derivation of the approximate straight line is completed, and the created first curve is corrected by the coefficient by the correction means 10 (step S15). In the section where the image area ratio is low, the opening degree of the ink key K is plotted larger than the actual value, and when adjusting the opening degree of the ink key K, it is easier to adjust from the lower side. Therefore, with respect to the opening degree obtained by the least squares method, each section in which the section having a low image area ratio is subdivided (for example, in FIG. 5, 0% to 2% section, 2% to 4% section, 4%). Correction is performed by applying the coefficients set by the correction means 10 to the 8% to 8% section, the 8% to 12% section, the 12% to 16% section, and the 16% to 20% section (step S14). ). The coefficient used in the section of low image area ratio (0% to 20% in this embodiment, but may be changed) is set to a value less than 1. In this embodiment, the coefficient is selected and set from the range of 0.50 to 0.95. FIG. 5 shows the second curve 2R (value selected from the range of 0.50 to 0.95) corrected by multiplying the first curve 1R in the section where the image area ratio is from 0% to 20% by a coefficient (value selected from the range of 0.50 to 0.95). (See solid line) is drawn. In FIG. 5, the opening degree of the ink key K of the second curve 2R is smaller than the opening degree of the ink key K of the first curve 1R. Then, when the image area ratio is 20% or more, the values of the ink key opening degrees K of the first curve 1R and the second curve 2R are the same. That is, the coefficient is set to 1 in the section where the image area ratio is 20% or more. By setting in this way, the opening degree of the ink key K can be suppressed to a small value in a section having a low image area ratio. In this embodiment, in the low image area ratio up to 4%, the area is divided into 2% areas, and 4% or more is divided into 4% areas, which is larger than 2%. The coefficient can also be set so that the larger the image area ratio of the section area is, the larger the coefficient is in the low image area. Further, the coefficient may be set to a different value for each section area, or a plurality of areas may be set to the same value. In the ink key opening adjustment system of the present embodiment, the coefficient is set to 1 for the section where the opening degree of the ink key K of the first curve is desired to be adopted in the second curve even in the section having a low image area ratio. Can be set. Further, a coefficient larger than 1 can be set for a section in which the opening degree of the ink key K of the second curve is desired to be larger than that of the first curve.

In FIGS. 6 and 7, as described above, each section of the low image area ratio region of the first curve created by obtaining an approximate straight line of the plot in the section using the least squares method is multiplied by a coefficient of less than 1. The second curve created in the above is shown by a solid line. The dashed line curves in FIGS. 6 and 7 are the original curves. The second curve created by applying the coefficient as described above is an ink key smaller than the opening degree of the ink key K of the first curve (not shown in FIGS. 6 and 7) before applying the coefficient in the low image area ratio region. It becomes the opening degree of K.

When the correction is completed by multiplying the coefficient as described above, the process proceeds to the processing of the section where the number of plots is insufficient (step S15). Specifically, as shown in FIG. 6, in the section of the image area ratio where the plot is insufficient (12% to 20% in FIG. 6), the ink key K in the section before the section where the plot is insufficient The opening of the ink key of the original curve (the point where the image area ratio is 16%) exists between the maximum value of the opening and the minimum value of the opening of the ink key K in the section after the section where the plot is insufficient. Therefore, the opening degree of the ink key of the original curve is recorded as the opening degree of the ink key K of the second curve.

In addition, in the section of the image area ratio where the plot is insufficient (12% to 20% in FIG. 6), the maximum value of the opening of the ink key and the plot in the section before the section where the plot is insufficient are insufficient. If the opening degree of the ink key K of the original curve (the point where the image area ratio is 16%) does not exist between the minimum value of the opening degree of the ink key in the section after the existing section, it is shown in FIG. As described above, the point on the straight line connecting the minimum value of the opening degree of the ink key K in the subsequent section and the maximum value of the opening degree of the ink key K in the previous section is recorded as the opening degree of the ink key K in the second curve.

When the processing of the section where the plot is insufficient is completed as described above, if there is a section in which the slope of the straight line becomes negative, the processing of that section is performed (step S16). Specifically, when the opening degree of the ink key K at the first point on the second curve is higher than that point and the opening degree of the ink key K at the second point is lower, the two points are connected. If this happens, it will be a straight line with a negative slope, so select a point where the opening of the ink key K before the first point is low, make it a straight line with a positive slope, and set the opening of the ink key at the first point. do.

The opening degree of the ink key is adjusted to 100 steps based on the opening degree of the ink key at the point of the second curve obtained as described above (step S17). When the creation of the second curve is completed, the process returns to FIG. 2 and the processing after the creation of the second curve is performed (step S4). That is, the processing of FIG. 4 is performed. First, it is checked whether or not an error has occurred during the creation of the second curve (step S20). If it is determined that an error has occurred, a message stating that the second curve could not be created is displayed on the display unit (step S21), and the control is terminated. If it is determined in step S20 that no error has occurred, an abnormal value is checked (step S22), and the value at each point of the second curve exceeds the upper limit value or the lower limit value of the opening degree of the ink key K. If there is a point, it is determined that there is an abnormal value outside the range, the value at that point is corrected to the upper limit value or the lower limit value of the opening degree of the ink key K (step S23), and the corrected second curve is used. Displayed (step S24), and the control is terminated. If no abnormal value is found in the check for the abnormal value, the second curve is displayed (step S24), and the control is terminated.

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 embodiment, the value of the coefficient is set to be larger as the image area ratio of the section area is larger, but it may be set to the same value less than 1.

1 ... ink pot roller, 2 ... ink calling roller, 3 ... ink roller group, 4 ... rollover roller, 5 ... water boat, 6 ... water source roller, 7 ... plate cylinder, 8 ... data acquisition means, 9 ... correlation derivation Means, 10 ... correction means, 11 ... control unit, K ... ink key, S ... arrow

Claims (3)

A data acquisition means for acquiring opening data at the time of printing an OK sheet of an ink key corresponding to a low image area ratio in which the image area ratio set in the image area in which the print image is divided is lower than a predetermined value, and acquisition by the data acquisition means. The opening degree of the ink key is added to the correlation deriving means for deriving the correlation between the low image area ratio and the opening degree of the ink key based on the opening data of the ink key and the correlation derived by the correlation deriving means. An ink key opening adjustment system for a printing machine, which comprises a correction means for correcting by multiplying a coefficient to be reduced. The coefficient is set for each section area in which the image area ratio is subdivided for each value in a predetermined range, and the coefficient is set so as to increase as the image area ratio of the section area increases. The ink key opening adjustment system of the printing machine according to claim 1, which is characterized by this. A data acquisition step for acquiring opening data at the time of printing an OK sheet of an ink key corresponding to a low image area ratio in which the image area ratio set in the image area in which the print image is divided is lower than a predetermined value, and an acquisition in the data acquisition step. The opening degree of the ink key is added to the correlation derivation step for deriving the correlation between the low image area ratio and the opening degree of the ink key based on the opening data of the ink key, and the correlation derived by the correlation deriving means. A method for correcting the amount of ink in a printing machine, which comprises a correction step for correcting by multiplying a coefficient to be reduced.

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