JP4202342B2 - Ink supply amount automatic setting method of printing machine, ink supply amount automatic setting device and printing machine - Google Patents

Description

  The present invention relates to a method, an apparatus, and a printer for automatically setting an ink supply amount.

  In the printing machine, the ink supply amount can be adjusted not only by adjusting the opening degree of the ink key but also by adjusting the rotation amount of the ink source roller (ink source roller rotation amount). However, when the printing speed increases, the phenomenon that the ink supply amount on the printing paper surface decreases and the color becomes light as shown in FIG. 7 occurs, and therefore the ink source roller rotation amount needs to be set according to the printing speed. For this reason, a function (ink speed function) that defines the relationship between the printing speed and the ink source roller rotation amount as shown in FIG. 8 is registered in the printer. That is, by using this ink speed function to set the rotation amount of the ink base roller corresponding to the printing speed, it is possible to supply an appropriate amount of ink corresponding to the printing speed.

  Since the relationship between the printing speed and the rotation amount of the ink source roller varies depending on the printing material used for each printing unit, the ink speed function needs to be set for each printing unit. In order to set the ink speed function, for example, a measuring plate having a known line drawing rate in the width direction of the printing press (each key zone) is used. A measuring plate is prepared for each ink color (printing unit), and each measuring plate is attached to a printing unit of each color of the printing machine. Then, when printing is performed with the ink key opening corresponding to the line drawing ratio being printed, a printing sheet is obtained, and the density of the printing sheet is measured for each key zone using a handy densitometer, The ink source roller rotation amount is manually adjusted so that the average density of all the key zones or the density of the noticed key zone becomes the reference density. When the average density of all the key zones or the density of the noticed key zone becomes the reference density, the rotation amount of the ink source roller at that time is checked. Such an operation is performed by changing some printing speeds, and the relation between the printing speed and the ink source roller rotation amount is obtained from the correspondence between the ink source roller rotation amount and the printing speed, and set as an ink speed function.

By the way, conventionally, an operator obtains the relationship between the printing speed and the ink source roller rotation amount while adjusting the density manually, and sets the ink speed function.
However, manual density adjustment takes time, and so 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 adjustment of the ink supply amount 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 has been difficult to accurately determine the relationship between the printing speed and the ink source roller rotation amount.

  The present invention was devised in view of the above-described problems, and can accurately determine the relationship between the printing speed and the rotation amount of the ink source roller, and can accurately set the ink supply amount. It is an object to provide a setting method, an ink supply amount automatic setting device, and a printing machine.

In order to solve the above-mentioned problem, an automatic ink supply amount setting method for a printing press according to claim 1 of the present invention includes a step of performing printing using a measurement printing plate, and an average target color mixing halftone density or all key zones. A step of setting a target mixed color halftone density of a key zone of interest; a step of measuring an actual mixed color halftone density of a printed sheet obtained by printing using an IRGB densitometer disposed on a running line of the printed sheet; Obtaining a solid density deviation from the target mixed color halftone density and the actual mixed color halftone density; adjusting the ink source roller rotation amount based on the solid density deviation when the solid density deviation is greater than a predetermined value; and When the solid density deviation is less than the predetermined value, the relationship between the printing speed and the ink source roller rotation amount is calculated based on the printing speed and the ink source roller rotation amount at that time. It is characterized by performing the step of registering the result.

According to a second aspect of the present invention, there is provided an automatic ink supply amount setting method for a printing press according to the present invention, wherein the ink supply roller rotation amount is preset in accordance with the printing speed based on a pre-registered relationship between the printing speed and the ink supply roller rotation amount. Obtained by printing using an IRGB densitometer arranged on the running line of the printing sheet , a step of setting an average target color mixing halftone density of all key zones or a target color mixing halftone density of the key zone of interest. Measuring the actual mixed color halftone density of the printed sheet; obtaining the solid density deviation from the target mixed color halftone density and the actual mixed color halftone density; and the solid density when the solid density deviation is greater than a predetermined value. The step of adjusting the rotation amount of the ink fountain roller based on the deviation, and the printing speed and the rotation of the ink fountain roller at that time when the solid density deviation falls below a predetermined value. Calculates the relationship between the printing speed and the ink fountain roller rotation amount based on the bets, is characterized by performing the step of updating the relationship between the printing speed and the ink fountain roller rotation amount is above registration. In each of the methods according to claims 1 and 2, in the actual printing, the ink source roller rotation amount corresponds to the printing speed by using the relationship between the registered or updated printing speed and the ink source roller rotation amount. Can be automatically set.

A method for automatically setting an ink supply amount of a printing press according to a third aspect of the present invention is the method according to the first or second aspect , wherein the step of setting the target mixed color halftone density includes kcmy halftone dot area ratio data of the printed pattern. And a step of converting the halftone dot area ratio into a mixed color halftone density and setting it as a target mixed color halftone density based on a correspondence relationship between a predetermined halftone dot area ratio and the mixed color halftone density. .

The ink supply amount automatic setting device for a printing press according to the present invention as claimed in claim 4 comprises: an ink source roller provided in the printing width direction; and an average target color mixture density of all key zones or a target color mixture density of a target key zone. Target color mixing halftone density setting means, an IRGB densitometer arranged on the travel line of the printing sheet, and an actual color mixing halftone density measurement for measuring the actual color mixing halftone density of the printing sheet by operating the IRGB densitometer Means, solid density deviation calculating means for obtaining a solid density deviation from the target mixed color halftone density and the actual mixed color halftone density, and if the solid density deviation is larger than a predetermined value, the ink source roller is rotated based on the solid density deviation. Ink fountain roller rotation amount adjusting means for adjusting the amount, and when the solid density deviation becomes a predetermined value or less, the printing speed is based on the printing speed and the ink fountain roller rotation amount at that time. A relation calculating means for calculating the relationship between the ink fountain roller rotation amount, is characterized by comprising registration means for registering the operation result of the relationship calculating means.

An ink supply amount automatic setting device for a printing press according to the present invention according to claim 5 includes an ink base roller provided in a printing width direction, a registration unit that registers a relationship between a printing speed and an ink base roller rotation amount, and Based on the relationship between the printing speed registered in the registration means and the ink fountain roller rotation amount, preset means for presetting the ink fountain roller rotation amount in accordance with the printing speed, and the average target color mixture density or attention of all key zones The target color mixture halftone density setting means for setting the target color mixture halftone density of the key zone, the IRGB densitometer arranged on the running line of the print sheet, and the IRGB densitometer are operated to obtain the actual color mixture halftone density of the print sheet. An actual mixed color halftone density measuring means for measuring, and an ink original roller for adjusting an ink original roller rotation amount based on the solid density deviation when the solid density deviation is larger than a predetermined value When the solid density deviation falls below a predetermined value, a relational calculation that calculates the relationship between the printing speed and the ink original roller rotation amount based on the printing speed and the ink original roller rotation amount at that time. And updating means for updating the relation between the printing speed registered in the registration means and the ink source roller rotation amount to the calculation result of the relation calculation means. In each of the apparatuses according to claims 4 and 5 , at the time of actual printing, the ink source roller rotation amount corresponds to the printing speed by using the relationship between the registered or updated printing speed and the ink source roller rotation amount. Can be automatically set.

According to a sixth aspect of the present invention, there is provided a printing machine according to the fourth or fifth aspect , the ink supply amount automatic setting device according to claim 4, a printing unit to which ink is supplied via the ink base roller, and the ink supply amount automatic setting device. After the ink supply amount is automatically set by the above, a control device of a printing press that controls the main printing by the printing unit is provided.

  According to the method and apparatus for automatically setting the ink supply amount of the first printing press according to the present invention, manual color matching by an operator is unnecessary, and color matching can be performed completely automatically. Therefore, color matching 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 the relationship between the printing speed with high accuracy and the rotation amount of the ink base roller, 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 printing speed and the rotation amount of the ink source roller is automatically learned and updated during commercial printing. Even when the printing conditions are changed, it is possible to always obtain the relationship between the optimum printing speed and the rotation amount of the ink source roller. Therefore, it is possible to always perform color matching promptly and suppress the occurrence of waste paper.

  Furthermore, according to the printing machine of the present invention, since the main printing is performed after the ink supply amount is automatically set, the occurrence of damaged paper can be suppressed.

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 as a printing 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 that includes an ink key 7 and an ink base roller 6. In this type of ink supply device, the ink supply amount can be adjusted by the ink key opening degree which is the gap amount of the ink key 7 with respect to the ink source roller 6 and the rotation amount of the ink source roller 6 (ink source roller rotation amount). 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 and the ink base roller 6 is moderately kneaded in the ink roller group 5 and is supplied to the plate surface of the plate cylinder 4 after forming a thin film. 3 is transferred to the print sheet 8 as a picture. 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. Therefore, the rotation amount of the ink base roller 6 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 comprises a DSP (digital signal processor, which has a function corresponding to an actual mixed color halftone density measuring means) 11 and a PC (personal computer) 12 which are installed apart from the printing press. Color conversion unit (function equivalent to target color mixing halftone density setting means, target halftone dot area ratio calculating means, target single color halftone density calculating means, real halftone dot area ratio calculating means, actual single color halftone density calculating means, solid density deviation calculating means 14), an ink supply amount calculation unit 15, an on-line control unit 16, and an ink speed function calculation unit (having functions corresponding to relational calculation means, registration means, and update means) 18. 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 has various functions, and in particular has a function as an ink supply amount adjusting means (ink source roller rotation amount adjusting means, preset means) for adjusting the ink supply amount. A driving device (not shown) that rotates the original roller is controlled, and the rotation amount of the ink original roller can be adjusted independently for each ink original roller 6 of each printing unit 2a, 2b, 2c, 2d. The control device 20 also has a function of giving a command for automatically executing other control elements of the printing press and processes of the entire printing press in accordance with a preset program.

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, the processing content when a new ink speed function indicating the relationship between the printing speed and the ink base roller rotation amount is set will be described with reference to FIG.
When setting a new relationship between the printing speed and the rotation amount of the ink fountain roller, first use a measuring plate with a known image area ratio in the printing width direction (for each key zone), Printing is performed with the ink key opening set to an ink supply amount (ink key opening) corresponding to the line drawing rate (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 in the entire key zone (entire surface) or the key zone of interest, and the average mixed color halftone density (actual mixed color network based on the reflected light amount of the blank paper portion) is used. Density) I, R, G, B are calculated. 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 mixed color halftone densities I, R, G, and B calculated by the DSP 11 are input to the color conversion unit 14 of the PC 12 together with preset target mixed color halftone densities Io, Ro, Go, and Bo.

  In this embodiment, the target color mixture halftone density is obtained from the plate making data of the measurement printing plate (kcmy halftone dot 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). In step S110, the color conversion unit 14 uses this database 141 to calculate the average color mixture halftone density of all key zones corresponding to the inputted plate making data k, c, m, y or the average color mixture of the key zone of interest. The halftone density is obtained and set as the target color mixture halftone density Io, Ro, Go, Bo.

  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 is 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, 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 are within a predetermined value. If not within the predetermined value, as step S70, deviation amounts of the ink original roller rotation amount corresponding to the solid density deviations ΔDsk, ΔDsc, ΔDsm, ΔDsy (ink original roller rotation deviation amounts) ΔKk, ΔKc, ΔKm, ΔKy is calculated. The ink original roller rotation deviation amounts ΔKk, ΔKc, ΔKm, ΔKy are the current ink original roller rotation amounts Kk0, Kc0, Km0, Ky0 (the ink original roller rotation output to the control device 20 of the printing press in the process of the previous step S90). The ink supply amount calculation unit 15 performs an operation using an ink speed function, which is an increase / decrease amount with respect to the amounts Kk, Kc, Km, Ky). However, since the ink speed function is obtained from the printing result using the measurement printing plate as described above, a temporary ink speed function is used at the present stage where the formal ink speed function is not set. The ink speed function is a function showing the correspondence between the printing speed and the ink source roller rotation amount K (Kk, Kc, Km, Ky) in order to obtain the reference density. The printing speed can be taken from the printing machine main body. 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 the reference density with respect to the printing speed is obtained. The ink original roller rotation amount K for obtaining the ink original roller rotation deviation amount ΔK (ΔK = kd × K) for obtaining the solid density deviation ΔDs as zero is obtained as a product of these.

  Next, in step S80, the online control unit 16 converts the ink source roller rotation deviation amounts ΔKk, ΔKc, ΔKm, and ΔKy calculated by the color conversion unit 14 from the printing units 2a, 2b, 2c, and 2d to the line sensor type. Correction is made in consideration of the number of sheets up to the IRGB densitometer 1, the reaction time of the ink base roller 6 per hour, and the printing speed. In this correction, after the ink origin roller rotation signal is input, the ink origin roller 6 moves, the ink origin roller rotation amount is changed, the amount of ink supplied to the printing sheet changes, and the IRGB densitometer 1 reflects the amount of reflected light. This takes into account the time delay until the change is detected. As such an online feedback control system having a large dead time, for example, PI control with dead time compensation is optimal. In step S90, the online control unit 16 adds the corrected ink original roller rotation deviation amount (online control ink original roller rotation deviation amount) ΔKk, ΔKc, ΔKm, ΔKy to the current ink original roller rotation amounts Kk0, Kc0, Km0. , Ky0 are added, and the ink control roller rotation amounts Kk, Kc, Km, and Ky for online control are input to the control device 20 of the printing press as ink control roller rotation signals.

  The control device 20 of the printing press again sets the ink source rollers 6 of the printing units 2a, 2b, 2c, 2d based on the ink source roller rotation signals Kk, Kc, Km, Ky transmitted from the arithmetic unit 10 as step S0. Adjust the amount of rotation and print. As a result, the ink supply amount of each ink color is controlled so as to meet the target density for each printing unit 2a, 2b, 2c, 2d.

  On the other hand, if the solid density deviations ΔDsk, ΔDsc, ΔDsm, and ΔDsy are within the predetermined values in step S65, the ink speed function calculation unit 18 determines in step S120 that the printing speed and the current ink source roller rotation amount K ( Based on (Kk0, Kc0, Km0, Ky0), an ink speed function indicating a relationship between the printing speed and the ink source roller rotation amount is obtained. The current printing speed can be acquired from the printing machine main body. In step S <b> 130, the ink speed function calculation unit 18 registers the obtained ink speed function in the database 181. Then, the processing as described above is performed by changing some printing speeds, and in the subsequent commercial printing (main printing), the rotation amount of the ink base roller is automatically set by using the newly set ink speed function. Will be.

  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 is performed completely automatically. Therefore, color matching can be performed accurately and at high speed, and since the density measurement is performed online by the IRGB densitometer 1, color matching before dry-down is possible. For this reason, it is possible to obtain a highly accurate ink speed function and to significantly reduce the waste paper for color matching.

In commercial printing after the ink speed function has been set once, the ink supply amount automatic setting process according to the flowchart of FIG. 4 is performed only when the printing speed is changed. Hereinafter, the automatic ink supply amount setting process after the ink speed function has been set will be described with reference to FIG.
In the first step S200, the ink source roller rotation amount is preset for each of the printing units 2a, 2b, 2c, and 2d using the ink speed function registered in the database 181 and the printing speed in the current printing. Then, ink is supplied with the preset ink source roller rotation amount, and printing is performed (step S210).

  In step S220, the IRGB densitometer 1 measures the reflected light amounts i ', r', g ', b' of each pixel of the print sheet 8, and the average actual mixed color halftone density of all key zones or the key of interest. The average actual mixed color halftone density I, R, G, B of the zone is obtained. In step S230, it is determined whether the solid density deviations ΔDsk, ΔDsc, ΔDsm, and ΔDsy of each ink color 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. Is required.

  If the solid density deviations ΔDsk, ΔDsc, ΔDsm, ΔDsy are not within the predetermined values in step S230, the inks of the printing units 2a, 2b, 2c, 2d are obtained by the processing in steps S70, S80, S90 of FIG. The original roller rotation amount is adjusted according to the solid density deviations ΔDsk, ΔDsc, ΔDsm, ΔDsy (step S260). On the other hand, if the solid density deviations ΔDsk, ΔDsc, ΔDsm, ΔDsy are within the predetermined values, in step S240, the printing speed and the ink original roller rotation amount are determined based on the printing speed and the current ink original roller rotation amount. A new ink velocity function that indicates In step S250, the ink speed function registered in the database 181 is updated to the newly obtained ink speed function.

As described above, according to the ink supply amount automatic setting method according to the present embodiment, since the ink speed function is automatically learned and updated at the time of commercial printing, even when the printing conditions change from the initial printing time, It is possible to always obtain the relationship between the optimum printing speed and the rotation amount of the ink base roller. Therefore, it is possible to always perform color matching promptly and suppress the occurrence of waste paper.
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 printing speed and the ink source roller rotation amount is defined as an ink speed function, but a map indicating the relationship between the printing speed and the ink source roller rotation amount may be registered. . That is, there is no limitation on the format that defines the relationship between the printing speed and the ink source roller rotation amount.

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.
Note that, as the measurement printing plate according to the present embodiment, for example, a printing plate having a different image area ratio for each key zone, or a full plate printing plate can be used.

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 ink speed function newly. It is a flowchart which shows the processing flow of the automatic setting process of the ink supply amount after an ink speed 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. It is a figure which shows the relationship between a printing speed and the ink density on the printing paper surface. It is a figure which shows an example of the ink speed function which shows the relationship between printing speed and the ink original roller rotation amount.

Explanation of symbols

DESCRIPTION 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 Print sheet 10 Arithmetic unit 11 DSP
12 PC
14 Color conversion unit 15 Ink supply amount calculation unit 16 Online control unit 18 Ink speed function calculation unit 20 Control device built in printing press

Claims (6)

Printing with a measuring plate, and
Setting an average target color halftone density for all key zones or a target color halftone density for the key zone of interest;
Using an IRGB densitometer placed on the travel line of the print sheet, measuring the actual mixed color halftone density of the print sheet obtained by printing;
Obtaining a solid density deviation from the target color mixture halftone density and the actual color mixture halftone density;
Adjusting the ink source roller rotation amount based on the solid density deviation when the solid density deviation is larger than a predetermined value;
A step of calculating a relationship between the printing speed and the ink original roller rotation amount based on the printing speed and the ink original roller rotation amount at that time and registering the calculation result when the solid density deviation is equal to or less than a predetermined value; And an ink supply amount automatic setting method for a printing press. Presetting the ink source roller rotation amount according to the printing speed based on the relationship between the pre-registered printing speed and the ink source roller rotation amount;
Setting an average target color halftone density for all key zones or a target color halftone density for the key zone of interest;
Using an IRGB densitometer placed on the travel line of the print sheet, measuring the actual mixed color halftone density of the print sheet obtained by printing;
Obtaining a solid density deviation from the target color mixture halftone density and the actual color mixture halftone density;
Adjusting the ink source roller rotation amount based on the solid density deviation when the solid density deviation is larger than a predetermined value;
When the solid density deviation is less than or equal to a predetermined value, the relationship between the printing speed and the ink source roller rotation amount is calculated based on the printing speed and the ink source roller rotation amount at that time, and the registered printing And a step of updating a relationship between the speed and the rotation amount of the ink base roller . 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 . An ink base roller provided in the printing width direction;
A target mixed color halftone density setting means for setting an average target mixed color halftone density of all key zones or a target mixed color halftone density of a target key zone;
An IRGB densitometer disposed on the travel line of the printed sheet;
An actual color mixture halftone density measuring means for operating the IRGB densitometer to measure the actual color mixture halftone density of the printing sheet;
A solid density deviation calculating means for obtaining a solid density deviation from the target mixed color halftone density and the actual mixed color halftone density;
Ink source roller rotation amount adjusting means for adjusting the ink source roller rotation amount based on the solid density deviation when the solid density deviation is larger than a predetermined value;
When the solid density deviation is less than or equal to a predetermined value, a relation calculating means for calculating a relationship between the printing speed and the ink source roller rotation amount based on the printing speed and the ink source roller rotation amount at that time;
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 base roller provided in the printing width direction;
Registration means for registering the relationship between the printing speed and the rotation amount of the ink source roller;
Based on the relationship between the printing speed registered in the registration means and the ink original roller rotation amount, preset means for presetting the ink original roller rotation amount according to the printing speed;
A target mixed color halftone density setting means for setting an average target mixed color halftone density of all key zones or a target mixed color halftone density of a target key zone;
An IRGB densitometer disposed on the travel line of the printed sheet;
An actual color mixture halftone density measuring means for operating the IRGB densitometer to measure the actual color mixture halftone density of the printing sheet;
Ink source roller rotation amount adjusting means for adjusting the ink source roller rotation amount based on the solid density deviation when the solid density deviation is larger than a predetermined value;
When the solid density deviation is less than or equal to a predetermined value, a relation calculating means for calculating a relationship between the printing speed and the ink source roller rotation amount based on the printing speed and the ink source roller rotation amount at that time;
An ink supply amount automatic setting for a printing press, comprising: an updating means for updating a relation between a printing speed registered in the registration means and an ink base roller rotation amount to a calculation result of the relation calculating means. Equipment . An ink supply amount automatic setting device according to claim 4 or 5 ,
A printing unit to which ink is supplied via the ink base roller;
A printing machine comprising: a control device for a printing machine that controls the main printing by the printing unit after the ink supply amount is automatically set by the ink supply amount automatic setting device.

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