JP2005081681A - Automatic setting method for ink supply of printing machine, automatic presetting method for ink supply, automatic setting device for ink supply and automatic presetting device for ink supply - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately determine the relation between the rate of printing elements and the opening of an ink key and to accurately set an ink supply. <P>SOLUTION: Printing is conducted for each key zone by using a press plate for measurement different in the rate of printing elements from others and a real mixture color halftone density of each key zone is measured by an IRGB densitometer. Besides, a target mixture color halftone density is set on the basis of platemaking data. Each of these mixture color halftone densities is converted into a halftone dot area rate and further into a monochrome halftone density. Then, a solid density deviation corresponding to the deviation of a target monochrome halftone density from a real monochrome halftone density is determined and the opening of the ink key is regulated according to the solid density deviation. When the solid density deviation comes to be within a prescribed value, the relation between the rate of printing elements and the opening of the ink key is determined from the rate of printing elements and the opening of the ink key of each key zone and registered in a printing machine. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method and apparatus for automatically setting an ink supply amount and an ink preliminary supply amount in a printing press.

  In the printing press, the ink supply amount can be adjusted for each key zone by adjusting the opening of the ink key (ink key opening). Although it is necessary to set the ink supply amount according to the line rate of the printed pattern, the printing machine has a function (ink supply amount conversion) that defines the relationship between the line rate and the ink key opening as shown in FIG. Function) is registered. That is, by using this ink supply amount conversion function to set the ink key opening degree according to the line drawing rate, it is possible to supply an appropriate amount of ink according to the line drawing rate of the printed pattern.

  The ink supply amount conversion function needs to be set for each printing press because the relationship between the ink key opening degree and the ink supply amount is different for each printing press. In order to set the ink supply amount conversion function, a measuring plate as shown in FIG. 11 is used. This measurement printing plate is formed with a pattern in which the line drawing rate changes linearly from one side end to the other side end, and a solid band extending from one side end to the other side end. . A measuring plate is prepared for each ink color, and printing is performed by attaching each measuring plate to a printing press.

  When a printed sheet is obtained by printing, measure the solid band density of the printed sheet for each key zone using a handy densitometer, and adjust each ink key opening so that the solid band density reaches the specified reference density. To go. When the density of the solid band in all the key zones becomes the reference density, the ink key opening of each key zone is checked. Then, a relationship between the line drawing rate and the ink key opening is obtained from the correspondence between the ink key opening and the line drawing rate for each key zone, and set as an ink supply amount conversion function (see, for example, Patent Document 1).

  In the printing machine, an operation of preliminary ink supply is also performed. The preliminary ink supply means that an appropriate amount of ink is wound around each printing cylinder in advance prior to the start of printing so that a print sheet having a desired density can be obtained quickly after the start of printing. The preliminary supply amount of ink is determined by the cylinder rotation speed and the ink key opening from the cylinder insertion to the ink supply stop. Normally, the ink key opening is a fixed value corresponding to the line drawing rate of the printed pattern, and the cylinder rotation speed is changed. To adjust. In setting the ink preliminary supply amount, first, the cylinder rotation speed is set to an appropriate value, and printing is performed using a measuring plate as shown in FIG. On the measurement printing plate, a pattern is formed so that the line drawing ratio changes stepwise for each key zone.

When a printed sheet is obtained by printing, the pattern density is measured using a handy densitometer. The concentration measurement side may be an average of the values obtained by measuring a plurality of key zones, or may be measured on behalf of an arbitrary key zone. Then, the cylinder rotation speed is adjusted so that the density measurement value becomes a predetermined target density, and when the density measurement value reaches the target density, the cylinder rotation speed at that time is registered. From the next time, the printing cylinder is rotated at the registered cylinder rotation speed, and an amount of ink corresponding to the cylinder rotation speed and each ink key opening is preliminarily supplied.
JP 2001-328235 A

  As described above, conventionally, an operator obtains the relationship between the image line ratio and the ink key opening while manually adjusting the density, and sets the cylinder rotation speed for preliminary ink supply. However, it takes time to adjust the density manually, and as much waste paper is generated. In particular, in the case of a rotary press, since it is difficult to stop printing halfway, the amount of waste paper becomes extremely large.

  Further, since it depends on the operator's feeling, it is difficult to accurately match the reference density or the target density. Particularly in newspaper printing, the ink is drastically dried down, so that the color fades while the operator measures the printed sheet. Therefore, with the conventional method, it is difficult to accurately obtain the relationship between the image area ratio and the ink key opening. In addition, it is difficult to accurately set the preliminary ink supply amount.

The present invention was devised in view of the above-described problems, and is capable of accurately determining the relationship between the image line rate and the ink key opening, and setting the ink supply amount automatically. It is a first object to provide a method.
It is a second object of the present invention to provide an ink supply amount automatic setting method for a printing press that can always accurately set an ink supply amount even when printing conditions change.

Furthermore, a third object of the present invention is to provide a method for automatically setting a preliminary ink supply amount of a printing press that can accurately set a preliminary ink supply amount.
It is a fourth object of the present invention to provide an automatic ink preliminary supply amount setting method for a printing press that can always accurately set the preliminary ink supply amount even when printing conditions change.

  In order to achieve the above object, in the first ink supply amount automatic setting method of the present invention, first, printing is performed using a measurement printing plate having a different image line rate for each key zone. Also, a target mixed color halftone density is set for each key zone. As a method for setting the target mixed color halftone density, preferably, kcmy halftone dot area ratio data of the printed pattern is acquired, and the halftone dot area ratio is determined based on the correspondence between the halftone dot area ratio and the mixed color halftone density described later. Converted to density and set as target mixed color halftone density.

  When printing is started and a print sheet is obtained, the actual color mixture halftone density for each key zone width of the print sheet is measured using an IRGB densitometer. Then, the actual halftone dot area ratio of each ink color corresponding to the actual mixed color halftone density is obtained based on the correspondence relationship between the halftone dot area ratio of each ink color and the mixed color halftone density. As a method for obtaining the actual halftone dot area ratio from the actual mixed color halftone density, a database storing the relationship between the halftone dot area ratio of each ink color and the mixed color halftone density, for example, newspaper printing Japan established by the ISO / TC130 National Committee A database (conversion table) obtained by printing a color standard printed matter and actually measured by an IRGB densitometer may be used. More simply, a value approximated by a well-known Neugebauer equation may be used by using the database. it can. Further, based on the correspondence between the halftone dot area ratio and the mixed color halftone density, the target halftone dot area ratio of each ink color corresponding to the target mixed color halftone density is also obtained. The target halftone dot area ratio does not need to be obtained every time as the actual halftone dot area ratio, and may be obtained once as long as the target mixed color halftone density does not change. For example, the target dot area ratio may also be obtained when the target color mixture halftone density is set.

  Next, an actual monochrome halftone density corresponding to the actual halftone dot area ratio is obtained based on a correspondence relationship between a preset halftone dot area ratio and the monochrome halftone density. As a method of obtaining the actual monochrome dot density from the actual dot area ratio, a map or table showing the relationship between the monochrome dot density and the dot area ratio is prepared, and the actual dot area ratio is set in these maps or tables. Just apply. Further, based on the correspondence relationship between the halftone dot area ratio and the monochrome halftone density, a target monochrome halftone density corresponding to the target halftone dot area ratio is also obtained. The target monochromatic halftone density need not be obtained every time as in the case of the actual monochromatic halftone density, and may be obtained once as long as the target halftone dot area ratio does not change. For example, the target monochromatic halftone density may also be obtained when the target halftone dot area ratio is set.

  Next, based on the correspondence relationship between the halftone dot area ratio, the monochrome halftone density, and the solid density set in advance, the solid color corresponding to the deviation between the target monochrome halftone density and the actual monochrome halftone density under the target halftone dot area ratio. Obtain the concentration deviation. As a method for calculating the solid density deviation, a map or table showing the above-mentioned body correspondence may be prepared, and the target halftone dot area ratio, the target monochromatic halftone density, and the actual monochromatic halftone density may be applied to these maps and tables. More simply, the relationship may be approximated using a well-known Yule-Nielsen equation and obtained using this equation.

  When the solid density deviation is larger than a predetermined value, the ink key opening is adjusted based on the obtained solid density deviation, and the ink supply amount of each color is controlled for each ink key. If the solid density deviation in all key zones is less than or equal to the predetermined value, the relationship between the stroke rate and the ink key opening is calculated based on the stroke rate of each key zone and the ink key opening at that time. , The calculation result is registered. The relationship between the image line ratio and the ink key opening can be easily set using an API (Auto Preset Inking) function.

  Thus, according to the first automatic ink supply amount setting method of the printing press of the present invention, manual color matching by the operator is unnecessary, and color matching of each key zone is performed completely automatically. Therefore, color matching of each key zone can be performed accurately and at high speed, and density measurement is performed online using an IRGB densitometer, so that color matching before dry-down is possible. For this reason, it is possible to obtain a highly accurate relationship between the image area ratio and the ink key opening, and it is possible to greatly reduce the waste paper for color matching. Further, by performing color matching using an IRGB densitometer instead of a spectrometer, it is possible to reduce the cost of the measuring means and to sufficiently cope with a high-speed printing machine such as a newspaper rotary press.

  In order to achieve the above object, according to the second ink supply amount automatic setting method of the present invention, first, based on the relationship between the pre-registered image line rate and the ink key opening, the key zone of the printed pattern is printed. The ink key opening is preset according to the line drawing rate. As the relationship between the stroke rate and the ink key opening, preferably, the one calculated and registered by the first ink supply amount automatic setting method (for example, API function) is used. The printing plate used here is not a measurement printing plate used in the first ink supply amount automatic setting method, but may be a normal commercial printing plate. Similarly to the first ink supply amount automatic setting method, a target color mixture halftone density is set for each key zone. As a method for setting the target mixed color halftone density, preferably, kcmy halftone dot area ratio data of the printed pattern is acquired, and the halftone dot area ratio is mixed based on the correspondence between the predetermined halftone dot area ratio and the mixed color halftone density. Converted to halftone density and set as target mixed color halftone density.

  When printing is started and a print sheet is obtained, the actual color mixture halftone density for each key zone width of the print sheet is measured using an IRGB densitometer. Then, the actual halftone dot area ratio of each ink color corresponding to the actual mixed color halftone density is obtained based on the correspondence relationship between the halftone dot area ratio of each ink color and the mixed color halftone density. Further, based on the correspondence between the halftone dot area ratio and the mixed color halftone density, the target halftone dot area ratio of each ink color corresponding to the target mixed color halftone density is also obtained.

  Next, an actual monochrome halftone density corresponding to the actual halftone dot area ratio is obtained based on a correspondence relationship between a preset halftone dot area ratio and the monochrome halftone density. Further, based on the correspondence relationship between the halftone dot area ratio and the monochrome halftone density, a target monochrome halftone density corresponding to the target halftone dot area ratio is also obtained. A solid density corresponding to a deviation between the target monochrome halftone density and the actual monochrome halftone density under the target halftone dot area ratio based on a correspondence relationship between a predetermined halftone dot area ratio, a monochrome halftone density, and a solid density. Find the deviation. The details of the processing from the determination of the target color mixture halftone density to the determination of the solid density deviation are the same as the corresponding processing contents in the first ink supply amount automatic setting method, and therefore the details are omitted.

  When the solid density deviation is larger than a predetermined value, the ink key opening is adjusted based on the obtained solid density deviation, and the ink supply amount of each color is controlled for each ink key. If the solid density deviation in all key zones is less than or equal to the predetermined value, the relationship between the stroke rate and the ink key opening is calculated based on the stroke rate of each key zone and the ink key opening at that time. Then, the relationship between the registered image ratio and the ink key opening is updated.

  As described above, according to the method for automatically setting the ink supply amount of the second printing press of the present invention, the relationship between the image line rate and the ink key opening is automatically learned and updated at the time of commercial printing. Even when the printing conditions change, it is possible to always obtain the optimum relationship between the image area ratio and the ink key opening. Therefore, it is possible to always perform color matching promptly and suppress the occurrence of waste paper.

  The first ink supply amount automatic setting method can be implemented by an ink supply amount automatic setting device having the following configuration. An ink supply amount automatic setting device for a first printing machine according to the present invention includes an ink key provided in a printing width direction, and an IRGB densitometer (preferably a line sensor type IRGB densitometer) disposed on a running line of a printing sheet. In addition, target mixed color halftone density setting means, mixed color halftone density measuring means, target halftone dot area ratio calculating means, actual halftone dot area ratio calculating means, target single color halftone density calculating means, actual single color halftone density calculating means, solid density deviation calculation Means, ink key opening adjustment means, relational calculation means, and registration means.

  Among these, target mixed color halftone density setting means, mixed color halftone density measuring means, target halftone dot area ratio calculating means, actual halftone dot area ratio calculating means, target single color halftone density calculating means, actual single color halftone density calculating means, solid density deviation calculating The means, the ink key opening adjusting means, the relation calculating means, and the registration means can be realized as one function of a programmed computer. Each of these functions will be described. First, the target color mixture halftone density setting unit has a function of setting a target color mixture halftone density for each key zone when the print pattern is divided into key zones. The mixed color halftone density measuring means has a function of measuring the actual mixed color halftone density for each key zone of the print sheet using an IRGB densitometer. The target halftone dot area ratio calculating means is configured to set a target halftone dot area corresponding to the target mixed color halftone density based on a correspondence relationship between the halftone dot area ratio of each ink color and the mixed color halftone density (for example, Neugebauer equation). The actual dot area ratio calculating means has a function of determining the actual dot area ratio of each ink color corresponding to the actual mixed color halftone density based on the same correspondence. The target monochromatic halftone density calculation means has a function for obtaining a target monochromatic halftone density corresponding to the target halftone dot area ratio based on a correspondence relationship between a predetermined halftone dot area ratio and the monochromatic halftone density, and calculates an actual monochromatic halftone density. The means has a function of obtaining an actual monochromatic halftone density corresponding to the actual halftone dot area ratio based on the same correspondence. The solid density deviation calculating means calculates the target monochrome area density based on the target halftone dot area ratio based on a correspondence relationship between the halftone dot area ratio, the monochrome halftone density, and the solid density (for example, the Yule-Nielsen equation). It has a function for obtaining a solid density deviation corresponding to the deviation from the actual single color halftone density. The ink key opening adjustment means has a function of adjusting the ink key opening based on the solid density deviation when the solid density deviation is larger than a predetermined value. Then, when the solid density deviation in all key zones becomes equal to or less than a predetermined value, the relational calculation means calculates the line rate and the ink key opening based on the line drawing rate of each key zone and the ink key opening at that time. The registration unit has a function of registering the calculation result of the relationship calculation unit. Preferably, a conversion table that defines the correspondence between halftone dot area ratio, mixed color halftone density and color coordinate value in the IRGB densitometer, and the target halftone dot area ratio calculating means and the actual halftone dot area ratio calculating means, A target halftone dot area ratio or an actual halftone dot area ratio is obtained using this conversion table.

  Said 2nd ink supply amount automatic setting method can be implemented with the ink supply amount automatic setting apparatus of the following structures. The apparatus for automatically setting the ink supply amount of the second printing press according to the present invention includes an ink key provided in the printing width direction and an IRGB densitometer (preferably a line sensor type IRGB densitometer) arranged on the running line of the printing sheet. In addition, registration means, preset means, target mixed color halftone density setting means, mixed color halftone density measuring means, target halftone dot area ratio calculating means, actual halftone dot area ratio calculating means, target single color halftone density calculating means, actual single color halftone density calculating And a solid density deviation calculating means, an ink key opening adjusting means, a relation calculating means, and an updating means.

  Among these, registration means, target mixed color halftone density setting means, mixed color halftone density measuring means, target halftone dot area rate calculating means, actual halftone dot area rate calculating means, target single color halftone density calculating means, actual single color halftone density calculating means, solid The density deviation calculating means, the ink key opening adjusting means, the relation calculating means, and the registering means have the same functions as the corresponding devices in the first ink supply amount automatic setting device. The presetting means and the updating means can be realized as a function of a programmed computer, like the above-described means. The presetting unit has a function of presetting the ink key opening according to the line drawing rate for each key zone of the print pattern based on the relationship (for example, API function) between the line drawing rate registered in the registration unit and the ink key opening. The update means has a function of updating the relationship between the image line ratio registered in the registration means and the ink key opening to the calculation result of the relation calculation means.

  In order to achieve the above object, according to the first automatic ink supply amount setting method of the present invention, first, a measurement printing plate having a different line drawing rate for each key zone is used, and ink keys are opened in each key zone. The ink is preliminarily supplied by rotating the printing cylinder by a temporarily set rotation speed after setting the degree to a value corresponding to the line drawing ratio. Then, printing is performed with the pre-supplied ink. Further, a target mixed color halftone density is set for each key zone. As a method for setting the target mixed color halftone density, preferably, kcmy halftone dot area ratio data of the printed pattern is acquired, and the halftone dot area ratio is mixed based on the correspondence between the predetermined halftone dot area ratio and the mixed color halftone density. Converted to halftone density and set as target mixed color halftone density.

  When printing is started and a printed sheet is obtained, the actual color mixture halftone density of the minimum image area ratio key zone of the printed sheet is measured using an IRGB densitometer. Then, the actual halftone dot area ratio of each ink color corresponding to the actual mixed color halftone density is obtained based on the correspondence relationship between the halftone dot area ratio of each ink color and the mixed color halftone density. The method of obtaining the actual halftone dot area ratio from the actual mixed color halftone density is the same as the above-described ink supply amount automatic setting method. Further, based on the correspondence between the halftone dot area ratio and the mixed color halftone density, the target halftone dot area ratio of each ink color corresponding to the target mixed color halftone density is also obtained.

  Next, an actual monochrome halftone density corresponding to the actual halftone dot area ratio is obtained based on a correspondence relationship between a preset halftone dot area ratio and the monochrome halftone density. Further, based on the correspondence relationship between the halftone dot area ratio and the monochrome halftone density, a target monochrome halftone density corresponding to the target halftone dot area ratio is also obtained. The details of the processing from the determination of the target mixed color halftone density to the determination of the target single color halftone density are the same as the corresponding processing contents in the above-described ink supply amount automatic setting method. Then, the rotation speed of the printing cylinder corresponding to the target monochrome color density is calculated from the temporarily set rotation speed, the target monochrome color density, and the actual monochrome color density in the minimum image rate key zone, and the calculation result is set to the minimum image rate. It is registered as a set rotational speed for preliminarily supplying a corresponding amount of ink to the printing cylinder.

  Thus, according to the ink preliminary supply amount automatic setting method of the first printing press of the present invention, the ink preliminary supply amount is calculated completely automatically according to the printing result, not the operator's feeling. In addition, since the density measurement is performed online using an IRGB densitometer, it is not affected by dry-down. Therefore, the ink preliminary supply amount corresponding to the minimum image area ratio can be obtained accurately and at high speed, and the waste paper for determining the ink preliminary supply amount can also be reduced. Further, by performing color matching using an IRGB densitometer instead of a spectrometer, it is possible to reduce the cost of the measuring means and to sufficiently cope with a high-speed printing machine such as a newspaper rotary press.

  In order to achieve the above object, according to the second method of automatically setting the preliminary ink supply amount of the present invention, first, a measurement printing plate having a different image area ratio is used for each key zone, and the ink key is opened in each key zone. After setting the degree to the value corresponding to the line drawing rate, the printing cylinder is rotated by a predetermined number of revolutions, and an amount of ink corresponding to the minimum line drawing rate is preliminarily supplied to the printing cylinder. Rotate the printing cylinder to perform preliminary ink supply. Then, printing is performed with the pre-supplied ink. Further, a target mixed color halftone density is set for each key zone. As a method for setting the target mixed color halftone density, preferably, kcmy halftone dot area ratio data of the printed pattern is acquired, and the halftone dot area ratio is mixed based on the correspondence between the predetermined halftone dot area ratio and the mixed color halftone density. Converted to halftone density and set as target mixed color halftone density.

  When printing is started and a print sheet is obtained, the actual color mixture halftone density for each key zone width of the print sheet is measured using an IRGB densitometer. Then, the actual halftone dot area ratio of each ink color corresponding to the actual mixed color halftone density is obtained based on the correspondence relationship between the halftone dot area ratio of each ink color and the mixed color halftone density. The method of obtaining the actual halftone dot area ratio from the actual mixed color halftone density is the same as the above-described ink supply amount automatic setting method. Further, based on the correspondence between the halftone dot area ratio and the mixed color halftone density, the target halftone dot area ratio of each ink color corresponding to the target mixed color halftone density is also obtained.

  Next, an actual monochrome halftone density corresponding to the actual halftone dot area ratio is obtained based on a correspondence relationship between a preset halftone dot area ratio and the monochrome halftone density. Further, based on the correspondence relationship between the halftone dot area ratio and the monochrome halftone density, a target monochrome halftone density corresponding to the target halftone dot area ratio is also obtained. The details of the processing from the determination of the target mixed color halftone density to the determination of the target single color halftone density are the same as the corresponding processing contents in the above-described ink supply amount automatic setting method. Then, the number of rotations of the printing cylinder corresponding to the target monochrome color halftone density is calculated from the temporarily set rotation speed, the target monochrome color halftone density, and the average value of the actual monochrome color halftone density in each key zone. It is registered as a set rotational speed for preliminarily supplying a corresponding amount of ink to the printing cylinder.

  As described above, according to the ink preliminary supply amount automatic setting method for the second printing press of the present invention, the ink preliminary supply amount is calculated completely automatically according to the printing result, not the operator's feeling. In addition, since the density measurement is performed online using an IRGB densitometer, it is not affected by dry-down. Therefore, the ink preliminary supply amount corresponding to each image line ratio can be obtained accurately and at high speed, and the waste paper for determining the preliminary ink supply amount can also be reduced. Further, by performing color matching using an IRGB densitometer instead of a spectrometer, it is possible to reduce the cost of the measuring means and to sufficiently cope with a high-speed printing machine such as a newspaper rotary press.

  In order to achieve the above object, in the third automatic ink supply amount setting method of the present invention, first, the ink key opening degree of each key zone is set according to the line drawing rate for each key zone of the printed pattern. Then, the printing cylinder is rotated by a predetermined first set rotational speed, an amount of ink corresponding to the minimum image rate is preliminarily supplied to the printing cylinder, and the printing cylinder is further rotated by a predetermined second set rotational speed, An amount of ink corresponding to each line drawing rate is preliminarily supplied to the printing cylinder. The printing plate used here may be a printing plate for ordinary commercial printing. Then, printing is performed with the pre-supplied ink. Further, a target mixed color halftone density is set for each key zone. As a method for setting the target mixed color halftone density, preferably, kcmy halftone dot area ratio data of the printed pattern is acquired, and the halftone dot area ratio is mixed based on the correspondence between the predetermined halftone dot area ratio and the mixed color halftone density. Converted to halftone density and set as target mixed color halftone density.

  When printing is started and a print sheet is obtained, the actual color mixture halftone density for each key zone width of the print sheet is measured using an IRGB densitometer. Then, the actual halftone dot area ratio of each ink color corresponding to the actual mixed color halftone density is obtained based on the correspondence relationship between the halftone dot area ratio of each ink color and the mixed color halftone density. The method of obtaining the actual halftone dot area ratio from the actual mixed color halftone density is the same as the above-described ink supply amount automatic setting method. Further, based on the correspondence between the halftone dot area ratio and the mixed color halftone density, the target halftone dot area ratio of each ink color corresponding to the target mixed color halftone density is also obtained.

  Next, an actual monochrome halftone density corresponding to the actual halftone dot area ratio is obtained based on a correspondence relationship between a preset halftone dot area ratio and the monochrome halftone density. Further, based on the correspondence relationship between the halftone dot area ratio and the monochrome halftone density, a target monochrome halftone density corresponding to the target halftone dot area ratio is also obtained. The details of the processing from the determination of the target mixed color halftone density to the determination of the target single color halftone density are the same as the corresponding processing contents in the above-described ink supply amount automatic setting method.

  If there is a key zone with the minimum image line ratio, the printing cylinder corresponding to the target monochrome color density is calculated from the first set rotation speed, the target monochrome color density, and the actual monochrome color density in the minimum image ratio key zone. , And the first set rotational speed is updated based on the calculation result. Further, the number of rotations of the printing cylinder corresponding to the target monochrome color halftone density is calculated from the second set rotation speed, the target monochrome color halftone density, and the average value of the actual monochrome color halftone density in each key zone. Update the number.

  As described above, according to the ink preliminary supply amount automatic setting method of the third printing press of the present invention, the ink preliminary supply amount in the first step can be obtained again by the printing result of the commercial printing without using the measurement printing plate. Since the ink preliminary supply amount in the second step is completely automatically updated, an accurate ink preliminary supply amount can always be obtained even when the initial printing and the printing conditions are changed. Therefore, it is possible to always perform color matching promptly and suppress the occurrence of waste paper.

  The first ink preliminary supply amount automatic setting method can be implemented by an ink preliminary supply amount automatic setting device having the following configuration. The ink preliminary supply amount automatic setting device of the first printing press according to the present invention is arranged on an ink key provided in a printing width direction, a measuring printing plate having a different line drawing rate for each key zone, and a running line of a printing sheet. In addition to an IRGB densitometer (preferably a line sensor type IRGB densitometer), an ink key opening setting means, an ink preliminary supply means, a target color mixture halftone density setting means, a color mixture halftone density measurement means, a target halftone dot area ratio calculation means, An actual halftone dot area rate calculating means, a target single color halftone density calculating means, an actual single color halftone density calculating means, a rotation speed calculating means, and a registration means are provided as its constituent elements.

  Among these, the target mixed color halftone density setting means, the mixed color halftone density measuring means, the target halftone dot area ratio calculating means, the actual halftone dot area ratio calculating means, the target single color halftone density calculating means, and the actual single color halftone density calculating means are the ink supply. It has the same function as each corresponding means in the automatic quantity setting device. The ink key opening setting means, the ink preliminary supply means, the rotation speed calculation means, and the registration means can be realized as one function of a programmed computer, similar to the above-described means. The ink key opening setting means has a function of setting the ink key opening of each key zone to a value corresponding to the image drawing rate of the measurement printing plate. The ink preliminary supply means has a function of performing preliminary ink supply by rotating the printing cylinder by a temporarily set rotational speed. The rotation speed calculation means has a function of calculating the rotation speed of the printing cylinder according to the target monochrome color density from the temporarily set rotation speed, the target monochrome color density, and the actual monochrome color density in the minimum image rate key zone. The means has a function of registering the calculation result of the rotation speed calculation means as a set rotation speed for preliminarily supplying an amount of ink corresponding to the minimum image ratio to the printing cylinder.

  The second ink preliminary supply amount automatic setting method described above can be implemented by an ink preliminary supply amount automatic setting device having the following configuration. The ink preliminary supply amount automatic setting device of the second printing press according to the present invention is arranged on an ink key provided in the printing width direction, a measuring printing plate having a different line drawing rate for each key zone, and a printing sheet running line. In addition to the IRGB densitometer (preferably a line sensor type IRGB densitometer), the ink key opening setting means, the first step preliminary supply means, the second step preliminary supply means, the target color mixture halftone density setting means, and the color mixture halftone density measurement means , Target halftone dot area ratio calculating means, real halftone dot area ratio calculating means, target single color halftone density calculating means, real single color halftone density calculating means, rotation speed calculating means, and registration means.

  Among these, the target mixed color halftone density setting means, the mixed color halftone density measuring means, the target halftone dot area ratio calculating means, the actual halftone dot area ratio calculating means, the target single color halftone density calculating means, and the actual single color halftone density calculating means are the ink supply. It has the same function as each corresponding means in the automatic quantity setting device. The ink key opening setting means, the ink preliminary supply means, the rotation speed calculation means, and the registration means can be realized as one function of a programmed computer, similar to the above-described means. The ink key opening setting means has a function of setting the ink key opening of each key zone to a value corresponding to the image drawing rate of the measurement printing plate. The first step preliminary supply means has a function of rotating the printing cylinder by a predetermined number of revolutions and preliminarily supplying an amount of ink corresponding to the minimum image area ratio to the printing cylinder. The second step preliminary supply means has a function of preliminarily supplying ink by further rotating the printing cylinder by a temporarily set rotational speed after the preliminary ink supply by the first step preliminary supply means. The rotational speed calculation means has a function of calculating the rotational speed of the printing cylinder according to the target monochrome halftone density from the temporarily set rotational speed, the target monochrome halftone density, and the average value of the actual monochrome halftone density in each key zone. The means has a function of registering the calculation result of the rotation speed calculation means as a set rotation speed for preliminarily supplying an amount of ink corresponding to each image rate to the printing cylinder.

  The third automatic ink supply amount setting method can be implemented by an automatic ink supply amount setting device having the following configuration. An automatic ink supply amount setting device for a third printing press according to the present invention includes an ink key provided in the printing width direction, and an IRGB densitometer (preferably a line sensor type IRGB densitometer) disposed on the running line of the print sheet. ) In addition, the ink key opening setting means, the first step preliminary supply means, the second step preliminary supply means, the target mixed color halftone density setting means, the mixed color halftone density measuring means, the target halftone dot area ratio calculating means, the actual halftone dot area ratio Computation means, target monochrome color density calculation means, actual monochrome color density calculation means, first rotation speed calculation means, first update means, second rotation speed calculation means, and second update means are provided as constituent elements.

  Among these, the target mixed color halftone density setting means, the mixed color halftone density measuring means, the target halftone dot area ratio calculating means, the actual halftone dot area ratio calculating means, the target single color halftone density calculating means, and the actual single color halftone density calculating means are the ink supply. It has the same function as each corresponding means in the automatic quantity setting device. The ink key opening setting means, the ink preliminary supply means, the rotation speed calculation means, and the registration means can be realized as one function of a programmed computer, similar to the above-described means. The ink key opening setting means has a function of setting the ink key opening of each key zone in accordance with the image line ratio for each key zone of the printed pattern. The first step preliminary supply means has a function of rotating the printing cylinder by a predetermined first set rotational speed and preliminarily supplying an amount of ink corresponding to the minimum image area ratio to the printing cylinder. After the preliminary ink supply by the first step preliminary supply means, the second step preliminary supply means further rotates the printing cylinder by a predetermined second set rotational speed, and an amount of ink corresponding to each image line rate is applied to the printing cylinder. It has a function of preliminary supply. The first rotational speed calculation means, when there is a key zone with the minimum image line ratio, calculates the target monochrome network from the first set rotational speed, the target monochrome network density and the actual monochrome network density in the minimum image ratio key zone. The printing cylinder has a function of calculating the number of rotations of the printing cylinder according to the density, and the first updating unit has a function of updating the first set number of rotations based on the calculation result of the first number of rotations calculating unit. The second rotational speed calculation means has a function of calculating the rotational speed of the printing cylinder corresponding to the target monochrome halftone density from the second set rotational speed, the target monochrome halftone density, and the average value of the actual monochrome halftone density in each key zone. The second updating means has a function of updating the second set rotational speed based on the calculation result of the second rotational speed calculating means.

  According to the first method and apparatus for automatically setting the ink supply amount of the printing press of the present invention, manual color matching by the operator is unnecessary, and color matching of each key zone is performed completely automatically. Therefore, color matching of each key zone can be performed accurately and at high speed, and density measurement is performed online using an IRGB densitometer, so that color matching before dry-down is possible. For this reason, it is possible to obtain a highly accurate relationship between the image area ratio and the ink key opening, and it is possible to greatly reduce the waste paper for color matching.

  In addition, according to the method and apparatus for automatically setting the ink supply amount of the second printing press of the present invention, the relationship between the line rate and the ink key opening is automatically learned and updated at the time of commercial printing. Even when the printing conditions change, it is possible to always obtain the optimum relationship between the image area ratio and the ink key opening. Therefore, it is possible to always perform color matching promptly and suppress the occurrence of waste paper.

According to the ink preliminary supply amount automatic setting method and apparatus of the first printing press of the present invention, the ink preliminary supply amount is calculated completely automatically according to the printing result, not the operator's feeling. In addition, since the density measurement is performed online using an IRGB densitometer, it is not affected by dry-down. Accordingly, the ink preliminary supply amount corresponding to the minimum image area ratio can be obtained accurately and at high speed, and the waste paper for determining the preliminary ink supply amount can also be reduced. According to the automatic ink pre-supply amount setting method of the printing press, the ink pre-supply amount is calculated completely automatically according to the printing result, not the operator's feeling. In addition, since the density measurement is performed online using an IRGB densitometer, it is not affected by dry-down. Therefore, the ink preliminary supply amount corresponding to each image line ratio can be obtained accurately and at high speed, and the waste paper for determining the preliminary ink supply amount can also be reduced.

  Furthermore, according to the method for automatically setting the ink preliminary supply amount of the third printing press of the present invention, the ink preliminary supply amount in the first step, the Since the two-step ink pre-supply amount is completely automatically updated, an accurate ink pre-supply amount can always be obtained even when the initial printing and the printing conditions are changed. Therefore, it is possible to always perform color matching promptly and suppress the occurrence of waste paper.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a diagram showing a schematic configuration of a newspaper offset rotary press according to an embodiment of the present invention. The newspaper web offset press of this embodiment is a multi-color printing duplex printing machine, and ink colors [black (k), indigo (c), red (m), yellow (y )] Is provided for each printing unit 2a, 2b, 2c, 2d. In the present embodiment, the printing units 2 a, 2 b, 2 c, and 2 d are provided with an ink key type ink supply device including an ink key 7 and an ink source roller 6. In this type of ink supply device, the ink supply amount can be adjusted by the ink key opening, which is the gap amount between the ink key 7 and the ink base roller 6. A plurality of ink keys 7 are juxtaposed in the printing width direction, and the ink supply amount can be adjusted in the width unit of the ink key 7 (hereinafter, the ink supply unit width by the ink key 7 is referred to as a key zone). The ink whose supply amount is adjusted by the ink key 7 is moderately kneaded in the ink roller group 5, is supplied to the plate surface of the plate cylinder 4 after forming a thin film, and the ink adhering to the plate surface passes through the blanket cylinder 3. As shown in FIG. Although omitted in FIG. 1, the newspaper offset rotary press of this embodiment is a double-sided printing, and therefore a pair of printing units 2 a, 2 b, 2 c, and 2 d is provided so as to sandwich the conveyance path of the printing sheet 8. Blanket cylinders 3 and 3 are provided, and a plate cylinder 4 and an ink supply device are provided for each blanket cylinder 3.

  The newspaper offset rotary press of this embodiment includes a line sensor type IRGB densitometer 1 further downstream of the most downstream printing unit 2d. The line sensor type IRGB densitometer 1 reflects I (infrared light), R (red), G (green), and B (blue) reflection densities (mixed-color network) in the form of a line in the print width direction of the pattern color on the printing sheet 8. It is possible to measure the reflection density of the entire print sheet 8 or to measure the reflection density at an arbitrary position. Since the newspaper offset rotary press of this embodiment is a double-sided printing, the line sensor type IRGB densitometer 1 is arranged on both the front and back sides so as to sandwich the conveyance path of the printing sheet 8, and the reflection density on both the front and back sides can be measured. .

  The reflection density measured by the line sensor type IRGB densitometer 1 is transmitted to the arithmetic unit 10. The computing device 10 is a device that computes ink supply amount control data, performs computation based on the reflection density measured by the line sensor type IRGB densitometer 1, and matches the pattern color of the printing sheet 8 with the target color. The opening of the ink key 7 is calculated. Here, FIG. 2 is a diagram showing an ink supply amount automatic setting device of the newspaper offset rotary press according to one embodiment of the present invention, and at the same time, a functional block diagram focusing on the ink supply amount automatic setting function of the arithmetic unit 10. It is.

  The arithmetic unit 10 is composed of a DSP (digital signal processor) 11 and a PC (personal computer) 12 that are installed apart from the printing press. The PC 12 includes a color conversion unit 14, an ink supply amount calculation unit 15, an online system. Functions as a control unit 16, a key opening limiter calculation unit 17, and an API function calculation unit 18 are assigned. The line sensor type IRGB densitometer 1 is connected to the input side of the arithmetic device 10, and the control device 20 with a built-in printing press is connected to the output side. The control device 20 functions as an ink supply amount adjusting means for adjusting the ink supply amount for each key zone of the ink key 7, and controls an opening / closing device (not shown) that opens and closes the ink key 7, and each printing unit 2a, The key opening can be adjusted independently for each of the ink keys 7 of 2b, 2c, and 2d.

  FIGS. 3 and 4 are flowcharts showing an automatic ink supply amount setting process performed by the arithmetic unit 10. Hereinafter, the processing content by the arithmetic unit 10 will be described with reference to FIGS. First, processing contents when an API function (auto-preset inking function) as an ink supply amount conversion function indicating the relationship between the image line ratio and the ink key opening is newly set will be described with reference to FIG.

  In order to newly set the relationship between the line drawing rate and the ink key opening, first, printing is performed using a measurement printing plate as shown in FIG. 11 (step S0). Next, as step S10, the line sensor type IRGB densitometer 1 measures the amount of reflected light i ′, r ′, g ′, b ′ for each pixel on the entire surface of the printing sheet 8. The reflected light amounts i ′, r ′, g ′, b ′ of each pixel measured by the IRGB densitometer 1 are input to the DSP 11.

In step S20, the DSP 11 performs a moving average of the reflected light amounts i ′, r ′, g ′, and b ′ of each pixel in units of a predetermined number of printed sheets, so that the reflected light amount i, r of each pixel from which the noise component has been removed. , G, b are calculated. In step S30, the reflected light amounts i, r, g, and b are averaged for each key zone, and the mixed color halftone density (actual mixed color halftone density) I, R, G, B based on the reflected light amount of the blank paper portion is obtained. Calculate. For example, assuming that the reflected light amount of infrared light on the blank paper portion is ip and the average reflected light amount of infrared light in the key zone is ik, the actual mixed color halftone density I of infrared light is I = log ₁₀ (ip / ik) As required. The actual color mixture halftone densities I, R, G, B for each key zone calculated by the DSP 11 are input to the color conversion unit 14 of the PC 12 together with preset target color mixture halftone densities Io, Ro, Go, Bo.

  In the present embodiment, the target color mixture halftone density is obtained from the plate-making data of the measurement printing plate (kcmy area ratio data such as CIP3 data). The color conversion unit 14 of the PC 12 includes a database 141 that associates the halftone dot area ratio of each ink color with the mixed color halftone density. The database 141 is a printed paper based on the Japan Color standard established by the ISO / TC130 National Committee, and is measured with an IRGB densitometer [mixed color with halftone dot area ratio (k, c, m, y) of standard color] It is created on the basis of a conversion table that defines the correspondence between halftone density (I, R, G, B) and color coordinate values (L, a, b). Using this database 141, the color conversion unit 14 obtains the mixed color halftone density corresponding to the inputted plate making data k, c, m, y for each key zone, and sets it as the target mixed color halftone density Io, Ro, Go, Bo. Set.

  The color conversion unit 14 performs the processes of steps S40, S50, and S60. First, in step S40, each ink color halftone corresponding to the target mixed color halftone density Io, Ro, Go, Bo set in step S110 and the actual mixed color halftone density I, R, G, B calculated in step S30. Each point area ratio is calculated. For this calculation, the database 141 is used, and based on the correspondence relationship stored in the database 141, the halftone dot area ratio of each ink color corresponding to the target mixed color halftone density Io, Ro, Go, Bo is calculated as the target halftone dot area ratio ko, It is calculated as co, mo, yo, and the dot area ratio of each ink color corresponding to the actual mixed color halftone density I, R, G, B is calculated as the actual dot area ratio k, c, m, y.

  Next, in step S50, the color conversion unit 14 determines the monochrome halftone density of each ink color corresponding to the target halftone dot area ratios ko, co, mo, yo and the real halftone dot area ratios k, c, m, y. Calculate each. For this calculation, a map as shown in FIG. 5 is used. FIG. 5 shows an example of a map obtained by plotting the monochromatic halftone density actually measured when the halftone dot area ratio is changed as a characteristic curve, and is created from data measured in advance. In the example shown in FIG. 5, by comparing the black target halftone dot area ratio ko and the real halftone dot area ratio k with the map, the target single color halftone density Dako and the real single color halftone density Dak are obtained from the characteristic curves in the map. It has been demanded. In this way, the color conversion unit 14 obtains the target monochromatic halftone densities Dako, Dako, Damo, Dayo and the actual monochromatic halftone densities Dak, Dac, Dam, Day for each ink color.

  Next, in step S60, the color conversion unit 14 sets the solid density deviation ΔDsk of each ink color corresponding to the deviation between the target monochrome color density Dako, Dako, Damo, Dayo and the actual monochrome color density Dak, Dac, Dam, Day. , ΔDsc, ΔDsm, ΔDsy are calculated. The solid density also depends on the halftone dot area ratio. For the same monochrome halftone density, the higher the halftone dot area ratio, the lower the solid density. Therefore, the color conversion unit 14 performs calculations using a map as shown in FIG. FIG. 6 shows an example of a map in which the solid density actually measured when the monochromatic halftone density is changed is plotted as a characteristic curve for each halftone dot area ratio, and is created from data measured in advance. The color conversion unit 14 selects a characteristic curve corresponding to the target halftone dot area ratios ko, co, mo, and yo for each ink color from the map shown in FIG. 6, and sets the target monochromatic halftone densities Dako, Daco, The solid density deviations ΔDsk, ΔDsc, ΔDsm, ΔDsy are obtained by associating the Damo, Dayo with the actual monochromatic halftone densities Dak, Dac, Dam, Day. In the example shown in FIG. 6, when the target halftone dot area ratio ko of black is 75%, the target monochrome color density Dako and the actual single color halftone density Dak are checked against the map so that the black color is obtained from the 75% characteristic curve in the map. The solid density deviation ΔDsk is obtained.

  The solid density deviations ΔDsk, ΔDsc, ΔDsm, ΔDsy of each ink color calculated by the color conversion unit 14 are input to the ink supply amount calculation unit 15. First, in step S65, the ink supply amount calculation unit 15 determines whether the solid density deviations ΔDsk, ΔDsc, ΔDsm, and ΔDsy of all the key zones are within a predetermined value. If not within the predetermined value, the key opening deviation amounts ΔKk, ΔKc, ΔKm, ΔKy corresponding to the solid density deviations ΔDsk, ΔDsc, ΔDsm, ΔDsy are calculated as step S70. The key opening deviation amounts ΔKk, ΔKc, ΔKm, ΔKy are the current key opening Kk0, Kc0, Km0, Ky0 of each ink key 7 (the key opening output to the control device 20 of the printing press in the process of the previous step S100). Kk, Kc, Km, Ky), and the ink supply amount calculation unit 15 calculates using an API function. However, since the API function is obtained from the printing result using the measurement printing plate as described above, the temporary API function is used at the present stage where the formal API function is not set. The API function is a function indicating the correspondence between the image area ratio A (Ak, Ac, Am, Ay) of each key zone and the ink key opening K (Kk, Kc, Km, Ky) in order to obtain a reference density. is there. The image line ratio A can be obtained from the plate making data used in step S110. Specifically, the ratio kd (kd = ΔDs / Ds) of the solid density deviation ΔDs (ΔDsk, ΔDsc, ΔDsm, ΔDsy) with respect to the reference density Ds (Dsk, Dsc, Dsm, Dsy) is obtained, and at the same time with respect to the line drawing rate A The key opening K for obtaining the reference concentration is obtained using an API function, and a key opening deviation amount ΔK (ΔK = kd × K) for making the solid concentration deviation ΔDs zero is obtained as a product of these.

  Next, in step S80, the online control unit 16 sends the key opening deviation amounts ΔKk, ΔKc, ΔKm, ΔKy calculated by the color conversion unit 14 to the line sensor type IRGB from the respective printing units 2a, 2b, 2c, 2d. Correction is made in consideration of the number of sheets used up to the densitometer 1, the reaction time of the ink key 7 per hour, and the printing speed. This correction is detected as a change in the amount of reflected light by the IRGB densitometer 1 when the ink key 7 is moved after the key opening signal is input, the ink key opening is changed and the amount of ink supplied to the printing sheet is changed. The time delay until is taken into consideration. As such an online feedback control system having a large dead time, for example, PI control with dead time compensation is optimal. The online control unit 16 is for online control in which the current key opening Kk0, Kc0, Km0, Ky0 is added to the corrected key opening deviation (online control key opening deviation) ΔKk, ΔKc, ΔKm, ΔKy. The key opening degrees Kk1, Kc1, Km1, and Ky1 are input to the key opening limiter calculation unit 17.

  In step S90, the key opening limiter calculation unit 17 performs correction for restricting the upper limit value for the online control key openings Kk1, Kc1, Km1, and Ky1 calculated by the online control unit 16. This is a process for restricting an abnormal increase in the ink key opening due to an estimation error of the color conversion algorithm (the processes of steps SS40, S50, and S60) particularly in the low image area. Then, in step S100, the key opening limiter calculating unit 17 transmits the ink key opening Kk, Kc, Km, Ky whose upper limit value is restricted as a key opening signal to the control device 20 of the printing press.

In step S0, the control device 20 of the printing press again opens the opening of each ink key 7 of each printing unit 2a, 2b, 2c, 2d based on the key opening signals Kk, Kc, Km, Ky transmitted from the arithmetic unit 10. Adjust the and perform printing. As a result, the ink supply amount of each ink color is controlled so as to meet the target density for each key zone.
On the other hand, if the solid density deviations ΔDsk, ΔDsc, ΔDsm, ΔDsy of all the key zones are within the predetermined values in step S65, the API function calculation unit 18 determines the line drawing ratio A of each key zone as step S120. Based on (Ak, Ac, Am, Ay) and the current ink key opening K (Kk0, Kc0, Km0, Ky0), an API function indicating the relationship between the image ratio and the ink key opening is obtained. The line drawing ratio A can be obtained from the plate making data used in step S110. In step S130, the API function calculation unit 18 registers the obtained API function in the database 181. In the subsequent commercial printing, the ink key opening is set using the newly set API function.

  As described above, according to the ink supply amount automatic setting method according to the present embodiment, manual color matching by an operator is unnecessary, and color matching of each key zone is performed completely automatically. Therefore, color matching of each key zone can be performed accurately and at high speed, and density measurement is performed online by the IRGB densitometer 1, so that color matching before dry-down is possible. For this reason, it is possible to obtain a highly accurate API function, and it is possible to greatly reduce the waste paper for color matching. In commercial printing after the API function is once set, an ink supply amount automatic setting process according to the flowchart of FIG. 4 is performed. The ink supply amount automatic setting process after the API function is set will be described below with reference to FIG.

In the first step S200, for each key zone, the API function registered in the database 181 and the image area ratio for each key zone obtained from the plate making data of the printing plate used this time (printing plate for commercial printing) are used. Preset ink key opening. Then, ink is supplied at a preset ink key opening, and printing is performed (step S210).
In step S220, the IRGB densitometer 1 measures the reflected light amounts i ′, r ′, g ′, and b ′ of each pixel of the print sheet, and the actual mixed color network densities I, R, G, and B for each key zone. Ask for. In step S230, it is determined whether the solid density deviations ΔDsk, ΔDsc, ΔDsm, and ΔDsy of each ink color in all key zones are within a predetermined value. The solid density deviations ΔDsk, ΔDsc, ΔDsm, and ΔDsy are processed in steps S40, S50, and S60 of FIG. 3 based on the actual mixed color halftone densities I, R, G, and B and the target mixed color halftone densities Io, Ro, Go, and Bo. It is calculated by.

  If the solid density deviations ΔDsk, ΔDsc, ΔDsm, and ΔDsy are not within the predetermined values in step S230, the key opening degree of each key zone is determined as the solid density by the processing in steps S70, S80, S90, and S100 in FIG. Adjustments are made according to the deviations ΔDsk, ΔDsc, ΔDsm, and ΔDsy. On the other hand, if the solid density deviations ΔDsk, ΔDsc, ΔDsm, and ΔDsy in all the key zones are within the predetermined value, step S240 is performed based on the image line ratio of each key zone and the current ink key opening. A new API function indicating the relationship between the linearity and the ink key opening is obtained. In step S250, the API function registered in the database 181 is updated to the newly obtained API function.

  As described above, according to the ink supply amount automatic setting method according to the present embodiment, the API function is automatically learned and updated at the time of commercial printing. It is possible to obtain the relationship between the optimum image area ratio and the ink key opening. Therefore, it is possible to always perform color matching promptly and suppress the occurrence of waste paper.

  The newspaper offset rotary press of the present embodiment can automatically set the preliminary ink supply amount online using the IRGB densitometer 1. Hereinafter, the automatic ink supply amount setting method according to the present embodiment will be described with reference to FIGS.

  As shown in FIG. 7, the arithmetic unit 10 is connected with a motor 9 that independently drives the printing units 2a to 2d. Further, a database 19 is provided in which the number of rotations of the printing cylinder (the plate cylinder 4, the blanket cylinder 3, etc.) at the time of preliminary ink supply is registered. The arithmetic unit 10 reads the cylinder rotation speed from the database 19 at the time of preliminary ink supply, and rotates the motor 9 according to the cylinder rotation speed.

FIGS. 8 and 9 are flowcharts showing an automatic ink supply amount setting process performed by the arithmetic unit 10. Hereinafter, the processing content by the arithmetic unit 10 will be described with reference to FIGS. 8 and 9. First, the processing contents when the cylinder rotation speed at the time of preliminary ink supply is newly set will be described with reference to FIG.
First, in step S300, a measurement printing plate as shown in FIG. 12 is mounted on the printing machine, and the ink key opening of each key zone is set to a value corresponding to the line drawing ratio of the measurement printing plate. The ink is preliminarily supplied by rotating the printing cylinder by the set number of revolutions. The ink key opening can be set using an API function registered in the database 181. Then, printing is performed with the preliminarily supplied ink (step S310).

  When the print sheet is obtained, in step S320, the IRGB densitometer 1 is used to measure the actual mixed color halftone density I, R, G, B of the minimum image area ratio key zone of the print sheet. Then, using the database 141, the real dot area ratios k, c, m, y of the ink colors corresponding to the actual mixed color halftone densities I, R, G, B are obtained, and the target mixed color halftone densities Io, Ro, The target halftone dot area ratios ko, co, mo, yo for each ink color corresponding to Go, Bo are obtained. Next, based on the correspondence relationship between the halftone dot area ratio and the single color halftone density set in advance, the real single color halftone densities Dak, Dac, Dam, Day corresponding to the real halftone dot area ratios k, c, m, y are obtained, Similarly, target monochromatic halftone densities Dako, Dako, Damo, Dayo corresponding to the target halftone dot area ratios ko, co, mo, yo are also obtained. The above processing is the same as the processing in steps S40 and S50 in FIG.

Next, as step S330, the printing cylinder corresponding to the target monochrome color density by, for example, the following equation (1) is calculated from the temporarily set rotation speed of the printing cylinder, the target monochrome color density, and the actual monochrome color density in the minimum image area ratio key zone. Is calculated (first set rotational speed).
First set rotation speed = temporary setting rotation speed × (target monochrome color density / actual monochrome color density of minimum image area ratio key zone) (1)
In step S340, the printing cylinder is rotated by the first set rotational speed obtained in step S330, and an amount of ink corresponding to the minimum image line ratio is preliminarily supplied to the printing cylinder (first step preliminary supply). Subsequently, in step S350, the printing cylinder is further rotated by a temporarily set rotation speed to preliminarily supply ink. In step S360, printing is performed using the ink preliminarily supplied in steps S340 and S350.

  When the print sheet is obtained, the actual color mixture halftone densities I, R, G, and B of each key zone of the print sheet are measured using the IRGB densitometer 1 in step S370. Then, the same monochromatic halftone densities Dak, Dac, Dam, and Day are obtained from the actual mixed color halftone densities I, R, G, and B by the same process as the processes of steps S40 and S50 in FIG. 3, and the target mixed color halftone density Io, Target monochromatic halftone densities Dako, Dako, Damo, Dayo are obtained from Ro, Go, Bo.

Next, as step S380, the printing cylinder according to the target monochrome color density by the following equation (2), for example, from the temporarily set rotation speed of the printing cylinder, the target monochrome color density, and the average value of the actual monochrome color density of each key zone. Is calculated (second set rotational speed).
Second set rotational speed = temporary set rotational speed × (target monochromatic halftone density / average actual monochromatic halftone density of each key zone) (2)
In step S390, the first set rotation speed and the second set rotation speed obtained in steps S330 and S380 are registered in the database 19, respectively. In the subsequent commercial printing, preliminary ink supply is performed at each newly registered cylinder rotation speed.

  As described above, according to the ink preliminary supply amount automatic setting method according to the present embodiment, the preliminary ink supply amount is calculated completely automatically according to the printing result, not the operator's feeling. In addition, since the density measurement is performed online by the IRGB densitometer 1, there is no influence of dry-down. Therefore, the ink preliminary supply amount in the first and second steps can be obtained accurately and at high speed, and the waste paper for determining the ink preliminary supply amount can also be reduced. In commercial printing after the cylinder rotation speed is once set, an automatic ink supply amount setting process according to the flowchart of FIG. 9 is performed. Hereinafter, the automatic ink supply amount setting process after the cylinder rotation speed has been set will be described with reference to FIG.

  First, in step S400, the ink key opening of each key zone is set according to the line rate for each key zone of the print pattern, the printing cylinder is rotated by the first set rotation speed, and the amount corresponding to the minimum image line rate is set. Is preliminarily supplied to the printing cylinder (first step preliminary supply). Subsequently, in step S410, the printing cylinder is further rotated by the second set rotation speed, and an amount of ink corresponding to each image line ratio is preliminarily supplied to the printing cylinder. In step S420, printing is performed using the preliminarily supplied ink.

  When the print sheet is obtained, the actual color mixture halftone density for each key zone of the print sheet is measured using the IRGB densitometer 1 in step S430. In step S370, the IRGB densitometer 1 is used to measure the actual mixed color halftone density I, R, G, B of each key zone of the print sheet. Then, the same monochromatic halftone densities Dak, Dac, Dam, and Day are obtained from the actual mixed color halftone densities I, R, G, and B by the same process as the processes of steps S40 and S50 in FIG. 3, and the target mixed color halftone density Io, Target monochromatic halftone densities Dako, Dako, Damo, Dayo are obtained from Ro, Go, Bo.

  In step S440, a determination is made regarding the line drawing rate of each key zone. The line drawing ratio of each key zone can be obtained from the plate making data. If there is a key zone with the minimum image line ratio (10%), as the step S450, from the first set rotation speed, the target single color halftone density, and the actual single color halftone density in the minimum image line rate key zone, for example, According to (3), the rotation speed (corrected first set rotation speed) of the printing cylinder corresponding to the target monochromatic halftone density is calculated.

Correction first set rotation speed = first set rotation speed × (target monochrome color density / actual monochrome color density of minimum image ratio key zone) (3)
For a key zone with a minimum image line ratio (10%) or more, in step S460, from the average value of the second set rotational speed, the target monochromatic halftone density, and the actual monochromatic halftone density in each key zone, for example, According to 4), the rotation speed (corrected second set rotation speed) of the printing cylinder corresponding to the target monochrome color density is calculated.

Correction second set rotational speed = second set rotational speed × (target monochromatic halftone density / average actual monochromatic halftone density of each key zone) (4)
In step S470, the first set speed and the second set speed registered in the database 19 are changed to the corrected first set speed and the corrected second set speed newly obtained in steps S450 and S460, respectively. Update.

  As described above, according to the ink preliminary supply amount automatic setting method according to the present embodiment, the rotation speed of the printing cylinder in the first step (the first step is determined based on the printing result of the commercial printing without using the measurement printing plate again. The set number of revolutions) and the number of revolutions of the printing cylinder in the second step (second set number of revolutions) are updated completely automatically, so that the ink is always accurate even when the initial printing and the printing conditions change. A preliminary supply can be obtained.

As mentioned above, although embodiment of this invention was described, embodiment of this invention is not limited to said thing. For example, in the embodiment, the relationship between the image rate and the ink key is defined as an API function, but a map indicating the relationship between the image rate and the ink key may be registered. In other words, there is no limitation on the format that defines the relationship between the line drawing rate and the ink key.
In addition to the method of providing the database 141 for associating the halftone dot area ratio of each ink color with the mixed color halftone density, a well-known Neugebauer equation defining the correspondence between the halftone dot area ratio of each ink color and the mixed color halftone density is used. A method of calculating the mixed color halftone density by storing the halftone dot area ratio of each ink color in this equation can be adopted.

  In addition to a method for obtaining a solid density deviation of each ink color corresponding to a deviation between the target monochrome color density and the actual monochrome color density using a map as shown in FIG. 6, the dot area ratio, the monochrome color density, and the solid color density. A method of calculating a solid density deviation by storing a known Yule-Nielsen formula that defines the correspondence with density and applying the target halftone dot area ratio, actual halftone dot area percentage, and monochrome halftone density to this formula is also available. is there.

  In the embodiment, a line sensor type IRGB densitometer is used, but a spot type IRGB densitometer may be used to scan the print sheet two-dimensionally.

1 is a diagram showing a schematic configuration of a newspaper offset rotary press according to an embodiment of the present invention. FIG. 2 is a functional block diagram focusing on an ink supply amount automatic setting function of the arithmetic device in FIG. 1. It is a flowchart which shows the processing flow in the case of setting an API function newly. It is a flowchart which shows the processing flow of the automatic setting process of the ink supply amount after an API function is set. 6 is a map that associates a monochrome halftone density with a halftone dot area ratio. 6 is a map that associates a solid density with a halftone dot area ratio and a monochrome halftone density. FIG. 10 is a block diagram illustrating input / output of signals to / from an arithmetic unit when attention is paid to an automatic ink supply amount setting process. It is a flowchart which shows the processing flow in the case of newly setting the cylinder rotation speed at the time of ink preliminary supply. It is a flowchart which shows the processing flow of the automatic setting process of the ink preliminary supply amount after a cylinder rotation speed is set. It is a figure which shows an example of the ink supply amount conversion function which shows the relationship between a line drawing rate and an ink key. It is a figure which shows an example of the printing plate for a measurement for setting an ink supply amount conversion function. It is a figure which shows an example of the printing plate for a measurement for setting the cylinder rotation speed at the time of ink preliminary supply.

Explanation of symbols

1 Line sensor type IRGB densitometer 2a, 2b, 2c, 2d Printing unit 3 Blanket cylinder 4 Plate cylinder 5 Ink roller group 6 Ink source roller 7 Ink key 8 Printing sheet 9 Motor 10 Arithmetic unit 11 DSP
12 PC
14 Color conversion unit 15 Ink supply amount calculation unit 16 Online control unit 17 Key opening limiter calculation unit 18 API function calculation unit 20 Control device built in printing press

Claims (12)

Printing using a measuring plate with a different line ratio for each key zone; and
A step of setting a target color mixture halftone density for each key zone;
Measuring the actual mixed color halftone density for each key zone of the print sheet using an IRGB densitometer;
Obtaining a target halftone dot area ratio of each ink color corresponding to the target mixed color halftone density based on a correspondence relationship between a predetermined halftone dot area ratio and the mixed color halftone density; and
Based on the correspondence between the halftone dot area ratio and the mixed color halftone density, obtaining a real halftone dot area ratio of each ink color corresponding to the actual mixed color halftone density;
Obtaining a target monochromatic halftone density corresponding to the target halftone dot area ratio based on a correspondence relationship between a predetermined halftone dot area ratio and a monochromatic halftone density;
A step of obtaining an actual monochrome dot density corresponding to the actual dot area ratio based on the correspondence between the dot area ratio and the monochrome dot density;
Based on the correspondence relationship between the halftone dot area ratio, the monochrome halftone density, and the solid density set in advance, the solid corresponding to the deviation between the target monochrome halftone density and the actual monochrome halftone density under the target halftone dot area ratio. Obtaining a concentration deviation;
When the solid density deviation is larger than a predetermined value, adjusting the ink key opening based on the solid density deviation;
When the solid density deviation in all the key zones is less than or equal to a predetermined value, the relationship between the line drawing rate and the ink key opening is calculated based on the line drawing rate of each key zone and the ink key opening at that time. A method for automatically setting an ink supply amount of a printing machine, comprising: performing a step of registering a calculation result. Presetting the ink key opening according to the line drawing rate for each key zone of the printed pattern based on the relationship between the pre-registered drawing rate and the ink key opening;
A step of setting a target color mixture halftone density for each key zone;
Measuring the actual mixed color halftone density for each key zone of the print sheet using an IRGB densitometer;
Obtaining a target halftone dot area ratio of each ink color corresponding to the target mixed color halftone density based on a correspondence relationship between a predetermined halftone dot area ratio and the mixed color halftone density; and
Based on the correspondence between the halftone dot area ratio and the mixed color halftone density, obtaining a real halftone dot area ratio of each ink color corresponding to the actual mixed color halftone density;
Obtaining a target monochromatic halftone density corresponding to the target halftone dot area ratio based on a correspondence relationship between a predetermined halftone dot area ratio and a monochromatic halftone density;
A step of obtaining an actual monochrome dot density corresponding to the actual dot area ratio based on the correspondence between the dot area ratio and the monochrome dot density;
Based on the correspondence relationship between the halftone dot area ratio, the monochrome halftone density, and the solid density set in advance, the solid corresponding to the deviation between the target monochrome halftone density and the actual monochrome halftone density under the target halftone dot area ratio. Obtaining a concentration deviation;
When the solid density deviation is larger than a predetermined value, adjusting the ink key opening based on the solid density deviation;
When the solid density deviation in all the key zones is less than or equal to a predetermined value, the relationship between the stroke rate and the ink key opening is calculated based on the stroke rate of each key zone and the ink key opening at that time. A method for automatically setting an ink supply amount of a printing machine, comprising: executing a step of updating a relationship between a registered line ratio and an ink key opening degree. The step of setting the target mixed color halftone density includes
Inputting kcmy halftone dot area ratio data of the printed pattern;
2. A step of converting a halftone dot area ratio into a mixed color halftone density based on a correspondence relationship between a preset halftone dot area ratio and a mixed color halftone density and setting the target mixed color halftone density as claimed in claim 1 or 2. The method for automatically setting the ink supply amount of the printing machine according to 2. Using a measuring plate with a different line ratio for each key zone, set the ink key opening in each key zone to a value according to the line ratio, and then rotate the printing cylinder by a temporary set number of rotations. Performing a preliminary supply;
Printing with the pre-supplied ink, and
Setting a target color mixture halftone density;
Using an IRGB densitometer to measure the actual color mixture halftone density of the minimum image area key zone of the print sheet;
Obtaining a target halftone dot area ratio of each ink color corresponding to the target mixed color halftone density based on a correspondence relationship between a predetermined halftone dot area ratio and the mixed color halftone density; and
Based on the correspondence between the halftone dot area ratio and the mixed color halftone density, obtaining a real halftone dot area ratio of each ink color corresponding to the actual mixed color halftone density;
Obtaining a target monochromatic halftone density corresponding to the target halftone dot area ratio based on a correspondence relationship between a predetermined halftone dot area ratio and a monochromatic halftone density;
A step of obtaining an actual monochrome dot density corresponding to the actual dot area ratio based on the correspondence between the dot area ratio and the monochrome dot density;
The number of rotations of the printing cylinder corresponding to the target monochrome color density is calculated from the temporarily set rotation speed, the target monochrome color density, and the actual monochrome color density in the minimum image area key zone. And a step of registering a corresponding amount of ink as a set rotational speed for preliminary supply to the printing cylinder. Using a measurement printing plate with a different line drawing rate for each key zone, setting the ink key opening in each key zone to a value corresponding to the line drawing rate, rotating the printing cylinder by a predetermined number of revolutions, and setting the minimum drawing rate Pre-supplying the printing cylinder with an amount of ink corresponding to
Furthermore, the step of rotating the printing cylinder by the provisional set number of rotations to perform preliminary ink supply;
Printing with the pre-supplied ink, and
Setting a target color mixture halftone density;
Measuring the actual mixed color halftone density for each key zone of the print sheet using an IRGB densitometer;
Obtaining a target halftone dot area ratio of each ink color corresponding to the target mixed color halftone density based on a correspondence relationship between a predetermined halftone dot area ratio and the mixed color halftone density; and
Based on the correspondence between the halftone dot area ratio and the mixed color halftone density, obtaining a real halftone dot area ratio of each ink color corresponding to the actual mixed color halftone density;
Obtaining a target monochromatic halftone density corresponding to the target halftone dot area ratio based on a correspondence relationship between a predetermined halftone dot area ratio and a monochromatic halftone density;
A step of obtaining an actual monochrome dot density corresponding to the actual dot area ratio based on the correspondence between the dot area ratio and the monochrome dot density;
The number of rotations of the printing cylinder corresponding to the target monochromatic halftone density is calculated from the above temporarily set rotation speed, the target monochromatic halftone density, and the average value of the actual monochromatic halftone density in each key zone, and the calculation result is obtained for each line rate. And a step of registering a corresponding amount of ink as a set rotational speed for preliminary supply to the printing cylinder. After setting the ink key opening of each key zone according to the line drawing rate of each key zone of the print pattern, the printing cylinder is rotated by the predetermined first set rotation speed, and the amount of ink corresponding to the minimum drawing line rate is set. Pre-feeding the printing cylinder;
A step of rotating the printing cylinder by a predetermined second set number of revolutions, and preliminarily supplying an amount of ink corresponding to each image line rate to the printing cylinder;
Printing with the pre-supplied ink, and
Setting a target color mixture halftone density;
Measuring the actual mixed color halftone density for each key zone of the print sheet using an IRGB densitometer;
Obtaining a target halftone dot area ratio of each ink color corresponding to the target mixed color halftone density based on a correspondence relationship between a predetermined halftone dot area ratio and the mixed color halftone density; and
Based on the correspondence between the halftone dot area ratio and the mixed color halftone density, obtaining a real halftone dot area ratio of each ink color corresponding to the actual mixed color halftone density;
Obtaining a target monochromatic halftone density corresponding to the target halftone dot area ratio based on a correspondence relationship between a predetermined halftone dot area ratio and a monochromatic halftone density;
A step of obtaining an actual monochrome dot density corresponding to the actual dot area ratio based on the correspondence between the dot area ratio and the monochrome dot density;
When there is a key zone of the minimum image area ratio, the rotation of the printing cylinder according to the target monochrome network density from the first set rotation speed, the target monochrome network density and the actual monochrome network density in the minimum image area key zone. Calculating the number, and updating the first set rotational speed according to the calculation result;
The number of rotations of the printing cylinder corresponding to the target monochrome color halftone density is calculated from the second set rotation speed, the target monochrome color density and the average value of the actual monochrome color density in each key zone, and the second setting rotation is calculated based on the calculation result. And a step of updating the number. A method for automatically setting an ink preliminary supply amount of a printing press. The step of setting the target mixed color halftone density includes
Inputting kcmy halftone dot area ratio data of the printed pattern;
5. A step of converting the halftone dot area ratio into a mixed color halftone density based on a correspondence relationship between a predetermined halftone dot area ratio and the mixed color halftone density and setting the target mixed color halftone density as a target color mixture halftone density. 7. A method for automatically setting a preliminary ink supply amount of a printing machine according to any one of 6 above. An ink key provided in the printing width direction;
A target mixed color halftone density setting means for setting a target mixed color halftone density for each key zone;
An IRGB densitometer disposed on the travel line of the printed sheet;
A color mixture halftone density measuring means for operating the IRGB densitometer to measure an actual color mixture halftone density for each key zone of the printing sheet;
A target halftone dot area ratio calculating means for obtaining a target halftone dot area ratio of each ink color corresponding to the target mixed color halftone density based on a correspondence relationship between a predetermined halftone dot area ratio and the mixed color halftone density;
Based on the correspondence between the halftone dot area ratio and the mixed color halftone density, an actual halftone dot area ratio calculating means for obtaining the actual halftone dot area ratio of each ink color corresponding to the actual mixed color halftone density,
A target monochromatic halftone density calculating means for obtaining a target monochromatic halftone density corresponding to the target halftone dot area ratio based on a correspondence relationship between a predetermined halftone dot area ratio and a monochromatic halftone density;
Based on the correspondence between the halftone dot area ratio and the monochromatic halftone density, an actual monochromatic halftone density calculating means for obtaining an actual monochromatic halftone density corresponding to the actual halftone dot area ratio;
Based on the correspondence relationship between the halftone dot area ratio, the monochrome halftone density, and the solid density set in advance, the solid corresponding to the deviation between the target monochrome halftone density and the actual monochrome halftone density under the target halftone dot area ratio. Solid density deviation calculating means for obtaining density deviation;
An ink key opening degree adjusting means for adjusting an ink key opening degree based on the solid density deviation when the solid density deviation is larger than a predetermined value;
When the solid density deviation in all key zones is less than or equal to a predetermined value, a relational calculation that calculates the relationship between the line drawing rate and the ink key opening based on the line drawing rate of each key zone and the ink key opening at that time. Means,
An ink supply amount automatic setting device for a printing press, comprising: a registration unit that registers a calculation result of the relational calculation unit. An ink key provided in the printing width direction;
Registration means for registering the relationship between the stroke rate and the ink key opening;
Preset means for presetting the ink key opening in accordance with the line drawing ratio for each key zone of the printed pattern, based on the relationship between the line drawing ratio registered in the registration means and the ink key opening;
A target mixed color halftone density setting means for setting a target mixed color halftone density for each key zone;
An IRGB densitometer disposed on the travel line of the printed sheet;
A color mixture halftone density measuring means for operating the IRGB densitometer to measure an actual color mixture halftone density for each key zone of the printing sheet;
A target halftone dot area ratio calculating means for obtaining a target halftone dot area ratio of each ink color corresponding to the target mixed color halftone density based on a correspondence relationship between a predetermined halftone dot area ratio and the mixed color halftone density;
Based on the correspondence between the halftone dot area ratio and the mixed color halftone density, an actual halftone dot area ratio calculating means for obtaining the actual halftone dot area ratio of each ink color corresponding to the actual mixed color halftone density,
A target monochromatic halftone density calculating means for obtaining a target monochromatic halftone density corresponding to the target halftone dot area ratio based on a correspondence relationship between a predetermined halftone dot area ratio and a monochromatic halftone density;
Based on the correspondence between the halftone dot area ratio and the monochromatic halftone density, an actual monochromatic halftone density calculating means for obtaining an actual monochromatic halftone density corresponding to the actual halftone dot area ratio;
Based on the correspondence relationship between the halftone dot area ratio, the monochrome halftone density, and the solid density set in advance, the solid corresponding to the deviation between the target monochrome halftone density and the actual monochrome halftone density under the target halftone dot area ratio. Solid density deviation calculating means for obtaining density deviation;
An ink key opening degree adjusting means for adjusting an ink key opening degree based on the solid density deviation when the solid density deviation is larger than a predetermined value;
When the solid density deviation in all key zones is less than or equal to a predetermined value, a relational calculation that calculates the relationship between the line drawing rate and the ink key opening based on the line drawing rate of each key zone and the ink key opening at that time. Means,
An ink supply amount automatic setting device for a printing press, comprising: an updating means for updating a relation between a line drawing ratio registered in the registration means and an ink key opening to a calculation result of the relation calculating means. . An ink key provided in the printing width direction;
A measuring plate with a different line ratio for each key zone,
Ink key opening setting means for setting the ink key opening of each key zone to a value corresponding to the image drawing ratio of the printing plate for measurement,
Ink pre-feeding means for pre-feeding ink by rotating the printing cylinder by a temporary set number of revolutions;
Target color mixing halftone density setting means for setting a target color mixing halftone density;
An IRGB densitometer disposed on the travel line of the printed sheet;
A color mixture halftone density measuring means for operating the IRGB densitometer to measure the actual color mixture halftone density of the minimum image area ratio key zone of the print sheet;
A target halftone dot area ratio calculating means for obtaining a target halftone dot area ratio of each ink color corresponding to the target mixed color halftone density based on a correspondence relationship between a predetermined halftone dot area ratio and the mixed color halftone density;
Based on the correspondence between the halftone dot area ratio and the mixed color halftone density, an actual halftone dot area ratio calculating means for obtaining the actual halftone dot area ratio of each ink color corresponding to the actual mixed color halftone density,
A target monochromatic halftone density calculating means for obtaining a target monochromatic halftone density corresponding to the target halftone dot area ratio based on a correspondence relationship between a predetermined halftone dot area ratio and a monochromatic halftone density;
Based on the correspondence between the halftone dot area ratio and the monochromatic halftone density, an actual monochromatic halftone density calculating means for obtaining an actual monochromatic halftone density corresponding to the actual halftone dot area ratio;
A rotation speed calculating means for calculating the rotation speed of the printing cylinder according to the target monochrome color density from the temporarily set rotation speed, the target monochrome color density, and the actual monochrome color density in the minimum image ratio key zone;
Ink for a printing press, comprising: a registration unit that registers a calculation result of the rotation number calculation unit as a set rotation number for preliminarily supplying an amount of ink corresponding to a minimum image rate to a printing cylinder Preliminary supply amount automatic setting device. An ink key provided in the printing width direction;
A measuring plate with a different line ratio for each key zone,
Ink key opening setting means for setting the ink key opening of each key zone to a value corresponding to the image drawing ratio of the printing plate for measurement,
A first step preliminary supply means for rotating the printing cylinder by a predetermined number of revolutions and preliminarily supplying an amount of ink corresponding to the minimum image area ratio to the printing cylinder;
After the preliminary supply of ink by the first step preliminary supply means, further, a second step preliminary supply means for preliminarily supplying the ink by rotating the printing cylinder by a temporarily set rotational speed;
Target color mixing halftone density setting means for setting a target color mixing halftone density;
An IRGB densitometer disposed on the travel line of the printed sheet;
A color mixture halftone density measuring means for operating the IRGB densitometer to measure an actual color mixture halftone density for each key zone of the printing sheet;
A target halftone dot area ratio calculating means for obtaining a target halftone dot area ratio of each ink color corresponding to the target mixed color halftone density based on a correspondence relationship between a predetermined halftone dot area ratio and the mixed color halftone density;
Based on the correspondence between the halftone dot area ratio and the mixed color halftone density, an actual halftone dot area ratio calculating means for obtaining the actual halftone dot area ratio of each ink color corresponding to the actual mixed color halftone density,
A target monochromatic halftone density calculating means for obtaining a target monochromatic halftone density corresponding to the target halftone dot area ratio based on a correspondence relationship between a predetermined halftone dot area ratio and a monochromatic halftone density;
Based on the correspondence between the halftone dot area ratio and the monochromatic halftone density, an actual monochromatic halftone density calculating means for obtaining an actual monochromatic halftone density corresponding to the actual halftone dot area ratio;
A rotation speed calculation means for calculating the rotation speed of the printing cylinder according to the target monochrome color density from the temporarily set rotation speed, the target monochrome color density and the average value of the actual monochrome color density in each key zone;
Ink for a printing press comprising: registration means for registering a calculation result of the rotation speed calculation means as a set rotation speed for preliminarily supplying an amount of ink corresponding to each line rate to a printing cylinder Preliminary supply amount automatic setting device. An ink key provided in the printing width direction;
Ink key opening setting means for setting the ink key opening of each key zone according to the line drawing rate for each key zone of the printed pattern,
A first step preliminary supply means for rotating the printing cylinder by a predetermined first set rotational speed and preliminarily supplying an amount of ink corresponding to the minimum image line ratio to the printing cylinder;
After preliminary supply of ink by the first step preliminary supply means, the printing cylinder is further rotated by a predetermined second set rotational speed, and the second step preliminary supply is performed to preliminarily supply an amount of ink corresponding to each image line ratio to the printing cylinder. Means,
Target color mixing halftone density setting means for setting a target color mixing halftone density;
An IRGB densitometer disposed on the travel line of the printed sheet;
A color mixture halftone density measuring means for operating the IRGB densitometer to measure an actual color mixture halftone density for each key zone of the printing sheet;
A target halftone dot area ratio calculating means for obtaining a target halftone dot area ratio of each ink color corresponding to the target mixed color halftone density based on a correspondence relationship between a predetermined halftone dot area ratio and the mixed color halftone density;
Based on the correspondence between the halftone dot area ratio and the mixed color halftone density, an actual halftone dot area ratio calculating means for obtaining the actual halftone dot area ratio of each ink color corresponding to the actual mixed color halftone density,
A target monochromatic halftone density calculating means for obtaining a target monochromatic halftone density corresponding to the target halftone dot area ratio based on a correspondence relationship between a predetermined halftone dot area ratio and a monochromatic halftone density;
Based on the correspondence between the halftone dot area ratio and the monochromatic halftone density, an actual monochromatic halftone density calculating means for obtaining an actual monochromatic halftone density corresponding to the actual halftone dot area ratio;
When there is a key zone of the minimum image area ratio, the rotation of the printing cylinder according to the target monochrome network density from the first set rotation speed, the target monochrome network density and the actual monochrome network density in the minimum image area key zone. First rotation number calculating means for calculating a number;
First updating means for updating the first set rotational speed according to a computation result of the first rotational speed computing means;
Second rotation speed calculation means for calculating the rotation speed of the printing cylinder corresponding to the target monochrome color density from the second set rotation speed, the target monochrome color density and the average value of the actual monochrome color density in each key zone;
An ink preliminary supply amount automatic setting device for a printing press, comprising: a second updating unit that updates the second set rotation number based on a calculation result of the second rotation number calculating unit.

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