JP2003231242A - Control unit and method for printing press - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily set value of a control parameter which is varied in optimum value by a printing speed like an ink speed or a damping speed to a proper value without relying on the skillful degree of an operator in the control unit, and to provide method for a printing press. <P>SOLUTION: With respect to the specific control parameter varied in optimum value by the printing speed among control parameters effecting on printing quality, a function showing the relation between the set value of the specific control parameter and the printing speed is stored in a data base at every image line ratio and printing condition. Prior to starting printing, the image line ratio data of a pattern printed this time is acquired from a pre-press process and the function corresponding to the acquired image line ratio data and printing condition data is searched from the data base. At the time of printing, the function obtained by searching is used to operate the set value of the specific control parameter corresponding to the present printing speed and the specific control parameter is automatically set to the operated set value. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control technique for a specific control parameter, such as the rotational speeds of an ink source roller and a dampening roller, whose optimum values vary depending on the printing speed, among control parameters that affect printing quality. Regarding

[0002]

2. Description of the Related Art In a printing machine, how much ink is attached to the printing surface of printed matter (shading, stains, etc.) depends on the amount of ink supplied to the printing surface and the amount of dampening water that emulsifies the ink. . In a printing machine equipped with an ink supply unit consisting of an ink source roller and an ink key, the ink supply amount was adjusted by the rotation speed of the ink source roller and the ink key opening, and the ink key opening was changed. In this case, the gap between the ink key and the ink source roller changes to change the amount of ink discharged from the ink fountain, and the amount of ink discharged also changes when the rotation speed of the ink source roller is changed. Normally, the total ink supply is adjusted by the rotation speed of the ink source roller,
The distribution of the ink supply amount in the width direction is adjusted by the ink key opening. Further, the supply amount of dampening water is adjusted by the rotation speed of the dampening roller that transfers the dampening water from the water ship to the ink roller group.

Therefore, by controlling the rotation speed of the ink source roller (hereinafter referred to as the ink speed) and the rotation speed of the dampening roller (hereinafter referred to as the dampening speed), the degree of attachment of the ink to the printing surface can be adjusted. However, it is known that the degree of ink attachment changes depending on the printing speed even at the same ink speed and dampening speed. Therefore, in order to obtain a printed matter of good print quality, it is necessary to set the ink speed and the dampening speed according to the printing speed, and the relationship between the ink speed and the printing speed, and the dampening speed and the printing speed. It has been done for some time to express the relationship as a function (called an ink velocity function and a dampening velocity function, respectively).

These ink velocity function and dampening velocity function are
Conventionally, it is set for each printing condition such as paper type and ink type based on the experience and knowledge of the operator. Paper type (coated paper,
The water absorption of ink and dampening water varies depending on the type of paper such as semi-coated paper, high-quality paper, medium-quality paper, rough paper, etc., and the density and adhesion to the printed surface also depends on the ink type (type by manufacturer or brand). This is because the optimum relationship between the ink speed and the dampening speed and the printing speed also changes when these paper types and ink types change. The ink speed function and dampening speed function that have been accumulated so far are stored in the database in association with the paper type and ink type.At the start of printing, the function according to the condition is selected from the database and preset in the printing machine. Is being done.

[0005]

By the way, it is empirically known that the optimum relationship between the ink speed or the dampening speed and the printing speed also affects the image coverage of the pattern to be printed. However, in the past, information about the streak rate could only be obtained by measuring the printed matter after actually printing, so unlike the known paper types and ink types in advance, inks corresponding to the streak rate were obtained. It was difficult to know the set values of speed and dampening speed.

For this reason, conventionally, there is no choice but to perform printing regardless of the image coverage of the pattern to be printed and to adjust the ink / fountain solution balance at each speed based on the experience of the operator. Even though the function and dampening speed function are stored in the database in association with the paper type and ink type, the operator's printing experience was still necessary. Further, since the adjustment depends on the skill level of the operator as described above, there is a problem that it takes a lot of time for the print adjustment and a lot of waste paper is generated.

Further, today, printing can be performed even during the speed-up process from the standby speed to the steady printing speed by gradually increasing the speed by alternately repeating the slow acceleration or constant speed operation and the rapid acceleration operation. A technique for doing so has been proposed. However, if it is necessary to balance the ink and the dampening water at each speed as described above, it may not be possible to obtain a printed matter of good print quality until the printing speed reaches a steady speed.

The present invention was devised in view of the above-mentioned problems, and it is easy to set control parameter values such as ink speed and dampening speed whose optimum values fluctuate depending on the printing speed without depending on the skill of the operator. It is an object of the present invention to provide a control device and a control method for a printing press, which can be set to an appropriate value.

[0009]

[Means for Solving the Problems] In recent years, in a prepress process, a CTP (Computer to plate) which directly produces a printing plate by a laser or the like based on image information without using a film unlike a conventional plate-making machine. The system is being used. In this CTP system, information necessary for plate making is sent from the image processing step to the plate making step as digital data. This digital data is currently internationally standardized (for example, CIP3 and CIP4), and in addition to the image information (pattern data) of the sample pattern to be printed, the color coordinate value for each pixel obtained by subdividing the sample pattern. ) Related information is included. Further, information on printing conditions (ink type, paper quality, etc.) can also be added. Therefore, by processing this digital data, it is possible to obtain the area ratio information of the pattern to be printed prior to the start of printing.

Therefore, in order to achieve the above-mentioned object, the control device of the printing press of the present invention is provided with an interface for acquiring the area ratio information of the pattern to be printed this time from the prepress step. In addition, regarding the specific control parameters (ink speed, dampening speed, etc.) whose optimum value varies depending on the printing speed among the control parameters that affect the printing quality, a function indicating the relationship between the setting value of the specific control parameter and the printing speed is set. It is provided with a database for storing each drawing rate and each printing condition. Further, a search means for searching the database for a function corresponding to the area ratio information and the printing condition information, and a set value of the specific control parameter according to the current printing speed are calculated by using the function obtained by the search, and the calculation is performed. And a control means having a function of automatically setting a specific control parameter to the set value.

According to the controller of the printing press having such a configuration, prior to the start of printing, the printing condition information is acquired in advance, and the image coverage ratio information of the pattern to be printed this time is acquired from the upstream prepress step, and the image is printed. A function corresponding to the linearity information and the printing condition information is searched from the database, and during printing, the set value of the specific control parameter corresponding to the current printing speed is calculated at any time using the function obtained by the search. It is possible to perform control such that the specific control parameter is changed and set at any time to the value obtained by the calculation. As a result, even a specific control parameter whose optimum value varies depending on the printing speed can be easily set to an appropriate value according to the drawing rate and printing conditions without depending on the skill level of the operator.

The function indicating the relationship between the set value of the specific control parameter stored in the database and the printing speed does not necessarily have to be prepared for every image area ratio, and is practically difficult. Therefore, even if the streak rate is divided into a plurality of sections that do not overlap each other, and a function indicating the relationship between the setting value of the specific control parameter and the print speed is stored in the database for each streak rate section and printing condition. Good. In this case, the searching means searches the database for a function corresponding to the area ratio classification corresponding to the area ratio information and the printing condition.

Alternatively, a reference function indicating the relationship between the set value of the specific control parameter and the printing speed at a specific image area ratio (reference image area ratio) as a reference is stored in a database for each printing condition, and the reference function is stored. A conversion function for converting into a function corresponding to each drawing rate may be stored in the database. In this case, the search means searches the database for a reference function corresponding to the print condition and a conversion function corresponding to the image rate information, and obtains a function corresponding to the current image rate and the print condition.

Further, not only the area ratio information but also the printing condition information may be acquired from the upstream prepress process. As described above, since the printing condition information can be added to the digital data for plate making, the printing condition information can also be acquired together with the area ratio information to facilitate the preparation at the start of printing. it can.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION 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 control device for a printing press according to an embodiment of the present invention. As shown in this figure, the control device according to the present embodiment uses the PPC (Pre
Press Computer) 20 and IPC (Intelligent Press Co)
ntroller) 10 and. The functions of the PPC 20 and the IPC 10 in this embodiment will be described below.

The PPC 20 is an interface for handling digital data for plate making created in the upstream prepress process on the side of the printing machine 1, and the prepress equipment (C
TP system) 2 and computer network 3 are connected. As digital data for plate making, for example,
CIP3 (Cooperation for Integration of Prepress,
Press and Postpress) standards and CIP4 (Cooperation
for Integration of Processes in Prepress, Press an
d Postpress) standard PPF (Print Production Forma)
t) Data can be used. These PPF data are image data (picture data) of a sample picture to be printed, and also include information about color coordinate values for each pixel obtained by subdividing the sample picture. Further, here, information regarding printing conditions (ink type, paper type, etc.) is also added. The PPC 20 has a function of receiving digital data for plate making output from the prepress device 2, processing the received digital data, and acquiring the image coverage of the pattern to be printed this time prior to printing. The streak rate can be acquired for each color, or the streak rate for the entire color can be acquired.

The IPC 10 is provided with a database 11, a selection processing section (search means) 12, and a preset section (control means) 13. Database 11 of these
Is an ink speed function storage unit 14 that stores a function (ink speed function) indicating the relationship between the rotation speed of the ink source roller and the printing speed, and a function (wetting speed) indicating the relationship between the rotation speed of the dampening roller and the printing speed. And a dampening speed function storage unit 15 for storing the dampening speed function). The ink speed function or the dampening speed function is stored in each of the storage units 14 and 15 for each ink type, paper type, and drawing rate. ing.

Since the ink type and the paper type are finite sets, it is possible to set the function for all types, but it is extremely difficult to set the function linearly for the entire range of the image coverage. Therefore, in the present embodiment, as shown in FIG. 2, the image area ratio is divided into three sections of a high image area rate, a medium image area ratio, and a low image area ratio according to the size, and the ink velocity function is divided according to each area. And a dampening rate function. FIG. 2 shows, as an example, a case where each function corresponding to coated paper and high-quality paper for a certain ink type is displayed as a map. Although the functions are displayed as maps in FIG. 2, each function may be stored in the database 11 in such a map, or may be stored as a mathematical expression. These functions should be created in advance by conducting tests and simulations in addition to conventional experience and knowledge for major functions, and in the rare cases, they should be created gradually by collecting data for each printing. To do.

The selection processing section 12 has a function of selecting an ink speed function and a dampening speed function according to the printing speed. Specifically, with the ink type and paper type used in the current printing and the line coverage of the pattern to be printed this time as the search conditions, ink velocity functions that match these search conditions are stored in the ink velocity function storage unit 14 of the database 11. Search for.
Similarly, the dampening speed function storage unit 15 is searched for a dampening speed function that matches the search condition. If the function matching the search condition is not stored in the database 11, a plurality of candidate functions within a predetermined approximation range are selected,
By performing weighted averaging on the selected candidate function according to the degree of approximation of the search condition, a function that matches the search condition is approximately calculated. Information necessary for the search, that is, ink type information, paper type information, and drawing rate information is input from the PPC 20 to the selection processing unit 12.

The preset section 13 has a function of presetting the ink speed function and the dampening speed function selected by the selection processing section 12 in the controller 1a of the printing press 1.
The preset unit 13 is configured to perform this preset processing before starting printing. In addition, the preset unit 13
And the controller 1a are connected online.

The controller 1a of the printing press 1 has a function of controlling the operation of the printing press 1 by using each function preset by the preset section 13. Specifically, by applying the current printing speed to the preset ink speed function, the rotation speed of the ink source roller is calculated according to the current printing speed, and the rotation speed of the ink source roller is changed to the calculated value. Set. Similarly, by applying the current printing speed to the preset dampening speed function, the rotation speed of the dampening roller is calculated according to the current printing speed, and the rotation speed of the dampening roller is changed to the calculated value. To do. Although the controller 1a is incorporated in the main body of the printing machine 1 in FIG. 1, it may be provided in the IPC 10 as a part of the function of the IPC 10, or externally of the printing machine 1.
It may be provided independently of the PC 10.

According to the control device having the above structure, the printing press 1 is controlled in the procedure shown in FIG. First, step S
In step 10, prior to the start of printing, the plate-making digital data related to the current printing is taken into the PPC 20 from the customer's prepress device 2 via the computer network 3. In step S20, the captured digital data is processed by the PPC 20, and the drawing rate information of the pattern to be printed this time is acquired from the digital data. In step S30, the obtained area ratio information is output to the IPC 10 together with the printing condition information included in the digital data.

In step S40, the selection processing unit 12 searches the database 11 using the printing condition information (ink type and paper type information) and the drawing rate information as search conditions, and matches the printing conditions and drawing rate of this time. An ink velocity function and a dampening velocity function are selected. The selected ink speed function and dampening speed function are preset in the controller 1a of the printing press 1 from the preset unit 13 in step S50.

When printing is started in step S60, the current printing speed is applied to each preset function in step S70, and the rotation speed of the ink source roller and the rotation of the dampening roller according to the current printing speed. The speed is calculated. Next, in step S80, each controller of the printing press 1 is controlled by the controller 1a, and each rotation speed of the ink source roller and the dampening roller is changed to the value calculated in step S70.

In step S90, a change in printing speed is detected. When the print speed is changed, the processes of steps S70 and S80 are performed again, and the rotation speed of the ink source roller and the rotation speed of the dampening roller are reset to the respective rotation speeds corresponding to the changed print speed. To be done. Then, in step S100, the end of printing is determined. Until printing is completed, step S90 or step S70-
The process of S90 is repeated.

With such control, the control device according to the present embodiment allows the respective rotation speeds of the ink source roller and the dampening roller to correspond to the printing speed according to the function according to the printing conditions and the image coverage. Since it is automatically set, it is possible to finely adjust the ink / dampening balance in accordance with the image rate and the printing condition in the entire printing speed range without depending on the skill of the operator. In particular, since the ink / dampening balance is slightly different depending on the drawing rate, it is possible to perform high-quality printing by changing the function according to the drawing rate. Therefore, as described above, even when the acceleration control is performed such that the gentle acceleration or the constant speed operation and the rapid acceleration operation are alternately repeated to increase the speed, the ink / dampening balance can be quickly followed. It is possible to further suppress the generation of waste paper during the rapid process.

Although one embodiment of the present invention has been described above, the present invention is not limited to this. For example, the digital data can be input to the PPC 20 by directly inputting online from the prepress step as in the above-described embodiment, or by using a floppy (R) disk or a CD-ROM.
A method of inputting via a storage medium such as a ROM can also be adopted. In addition, since the printing condition information can be easily obtained from others unlike the image rate information, only the image rate information is obtained from the digital data for plate making, and the ink type,
The printing condition information such as the paper type may be input manually by the operator.

Further, in the above-mentioned embodiment, the image area ratio is high,
Although the function is set for each of the three divisions of middle and low, it is of course possible to divide the function into finer divisions. Further, instead of setting a function for each section as described above, a function (reference function) corresponding to a specific drawing rate (reference drawing rate) serving as a reference is stored in the database 11 for each printing condition, and A conversion function for converting the reference function into a function corresponding to each drawing rate may be stored in the database 11. In this case, the standard function corresponding to the printing conditions and the conversion function corresponding to the line ratio of the current pattern are searched from the database 11, and the standard function is multiplied by the conversion function to obtain the current line ratio and the print ratio. Get the function according to the conditions.

Further, in the above-described embodiment, the case where the ink speed function and the dampening speed function are preset in the printing machine has been described. However, among the control parameters that affect the print quality, the optimum value varies depending on the printing speed. As for the control parameter, any function that presets a function indicating the relationship between the set value of the specific control parameter and the printing speed in the printing machine can be widely applied. Therefore, for example, the present invention can be applied to the case where a function indicating the relationship between the ink key opening and the printing speed is preset in the printing machine.

[0030]

As described in detail above, according to the control device and method of the printing press of the present invention, the printing speed among the control parameters that affect the printing quality is determined according to the function according to the printing conditions and the area ratio. Optimum value fluctuates depending on the print speed, so the setting value of the specific control parameter is automatically set, so that it can be specified according to the image rate and print conditions in the entire print speed area without depending on the skill level of the operator. It enables fine adjustment of control parameters.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a control device for a printing press according to an embodiment of the present invention.

FIG. 2 is a map showing an example of functions stored in the database of FIG.

FIG. 3 is a flowchart showing a control procedure of a printing press by the control device of FIG.

[Explanation of symbols]

1 printing machine 1a controller 2 preset equipment 3 computer network 10 IPC 11 Database 12 Selection processing unit 13 Preset section 14 Ink velocity function memory 15 Damping speed function memory 20 PPC

Claims (7)

[Claims] 1. A function indicating the relationship between the set value of the specific control parameter and the printing speed for a specific control parameter of which the optimum value varies depending on the printing speed among the control parameters that affect the printing quality, and the printing rate and printing. A database for each condition, an interface for acquiring the image coverage information of the pattern to be printed this time from the upstream prepress process, and a search means for searching the database for a function corresponding to the image coverage information and the printing condition information. And a control means for calculating the set value of the specific control parameter according to the current printing speed using the retrieved function and automatically setting the specific control parameter to the calculated set value. The control device of the printing machine. 2. A function indicating the relationship between the set value of the specific control parameter and the printing speed for each section of printing rate and printing conditions which are divided into a plurality of sections without overlapping with each other in the database. 3. The search means is configured to search the database for a function corresponding to the area ratio classification corresponding to the area ratio information and the printing condition. Control device of the printing machine. 3. The database stores a reference function indicating a relationship between a setting value of the specific control parameter at a reference image area ratio and the printing speed for each printing condition, and the reference function is provided for each image area. A conversion function for converting into a function according to the rate is stored, and the search means searches the database for a reference function according to the printing conditions and a conversion function corresponding to the image rate information, and the current image The control device for a printing press according to claim 1, wherein the control device is configured to obtain a function according to the rate and the printing condition. 4. The interface according to claim 1, wherein the interface is configured to obtain digital data for platemaking including both the image rate information and the printing condition information from an upstream prepress process. The control device for a printing press according to any one of 3 above. 5. The control device for a printing press according to claim 1, wherein the specific control parameter is a rotation speed of an ink source roller. 6. The control device for a printing press according to claim 1, wherein the specific control parameter is a rotation speed of a dampening roller. 7. A function indicating the relationship between the set value of the specific control parameter and the printing speed for a specific control parameter of which the optimum value varies depending on the printing speed among the control parameters that affect the printing quality, and a printing rate and printing. It is stored in the database in advance for each condition, the printing condition information is acquired in advance before starting printing, and the drawing ratio information of the pattern to be printed this time is acquired from the upstream prepress process. The function corresponding to the print condition information is searched from the database, and during printing, the set value of the specific control parameter according to the current print speed is calculated at any time using the function obtained by the search, and the calculation is performed. A method for controlling a printing press, wherein the specific control parameter is changed and set to the obtained value as needed.