JP2005271545A - Printing machine and printing density controlling method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a printing machine capable of preventing the generation of a paper loss by enabling an ink fountain roller to change in rotational speed accompanying the acceleration of the speed of the machine from an adjustment speed to a business operation speed at the operation start time with the ink density being always maintained within an allowable density range. <P>SOLUTION: The ink fountain roller comprising an ink supply device in the printing machine is divided into a plurality of predetermined divisions, and a plurality of ink supply control characteristics that are preset to cancel out the change in printing density, are prepared corresponding to the area ratios of patterns of a printed matter. The pattern area ratios of the printed matter are calculated for each predetermined division of the ink fountain roller. The ink supply characteristics prepared in correspondence with the pattern area ratios are applied for each calculated pattern area ratio. The amount of ink supplied from the ink supply device is made to vary for each predetermined division of the ink fountain roller. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a printing density control method for a printing press and a printing press, and more particularly to a printing density control method for a printing press and a printing press capable of quickly and easily adjusting ink density at the start of printing operation.

  At the start of operation of a general commercial web offset printing press, the printing speed is changed from the adjustment speed for changing the printing plate and adjusting the registration and color tone to the commercial operation speed. The ink source motor is controlled so that the ink key opening that has the most influence on the color tone is adjusted, and the rotation speed of the ink source roller is adjusted to the rotation speed corresponding to the printing speed in order to minimize the change in color tone due to the rise in color. Then, the rotation speed of the ink base roller is increased.

  In other words, in order to obtain a printed matter having a desired printing density, it is necessary to always balance the ink consumption and the ink supply amount. However, when the printing speed changes, the ink consumption per unit time also changes accordingly. In order to balance the changed consumption, it is necessary to change the ink key opening and the rotation speed of the ink source roller in the ink supply device.

  Since the rotation speed of the ink fountain roller for obtaining an appropriate printing density is not proportional to the printing speed, conventionally, a map (speed function map) of the rotation speed of the ink fountain roller with respect to this printing speed is used. It was stored in the ink supply control device, and the rotational speed of the ink base roller was controlled according to this speed map.

  However, in a general printing machine, even if the motor speed of the ink source roller is controlled according to the speed function map in this way, a large number of ink rollers are interposed from the ink source roller to the plate cylinder on which the printing plate is mounted. For this reason, there is a considerable delay time until the change in the rotation speed of the ink source roller is reflected in the change in the ink density transferred to the paper, and the printing density falls outside the allowable range, resulting in paper loss. There was a bug.

  This change in print density also depends on the pattern area ratio of the printed pattern. When the pattern area ratio is small, the decrease rate and recovery speed of the print density are slow, and when the pattern area ratio is large, both the decrease speed and the recovery speed are Get faster. That is, as shown in FIG. 3, the horizontal axis represents the pattern area ratio of the printed pattern, and the vertical axis represents the time until the density of ink transferred from the blanket cylinder to the paper changes after the rotation speed of the ink base roller changes. When (feed forward control time), the change in the ink density transferred from the blanket cylinder to the paper changes in a short time because the change rate increases as the ink consumption increases (that is, the pattern area ratio increases). If the ink consumption is small (that is, the pattern area ratio is small), the rate of change becomes small and the change takes a long time.

  For this reason, the applicant of the present application has proposed a printing machine that implements a printing density control method as shown in FIG. Therefore, the printing machine shown in FIG. 4 and its printing density control method will be briefly described. In FIG. 4, 1 is a roll of paper 2 and 3 is an infeed unit, 4 is black (K), cyan ( C), printing unit comprising printing units 4A, 4B, 4C, and 4D corresponding to colors such as magenta (M) and yellow (Y), 5 is a plate cylinder, 6 is a blanket cylinder, and 13 is each printing unit 4A and 4B. Main motor 13 for transmitting driving force to main shaft 13a for driving 4C and 4D, 17 is a speed function map, 19 is an ink key, 20 is an ink source roller, 21 is an ink source motor, 25 is a printing speed control device, and 50 is ink. A supply control device, 51 is an acceleration speed function map, 52 is a database, 53 is an input unit, and the paper 2 used for printing is set in the infeed unit 3 in the form of a roll-shaped web 1. It is. The infeed unit 3 includes an infeed drag (not shown) that sandwiches and rotates the paper 2 and a dancer roller that appropriately controls the tension of the paper 2. The infeed drag is a main motor driven by a main motor 13. It is connected to the shaft 13a so that the rotational driving force from the main motor 13 is transmitted through the main shaft 13a.

  The paper 2 drawn out from the web 1 by the infeed unit 3 is printed by the four printing units 4A, 4B, 4C, and 4D in the printing unit 4, and each of the printing units 4A, 4B, 4C, and 4D includes An ink supply device for supplying ink is provided. The ink supply device has an ink base roller 20 and a plurality of ink keys 19 arranged in parallel in the axial direction of the ink base roller 20, and a container formed by the ink base roller 20 and the ink key 19 serves as an ink fountain for storing ink. It has become. The amount of ink supplied from the ink fountain can be controlled not only by the rotation speed of the ink base roller 20 but also by the opening of the gap between the ink key 19 and the ink base roller 20 (ink key opening). The supplied ink is supplied to the plate cylinder 5 while being appropriately kneaded by a number of ink rollers (not shown), and further transferred from the plate cylinder 5 to the paper 2 via the blanket cylinder 6. Each of the printing units 4A, 4B, 4C, 4D is connected to the main shaft 13a and rotates in synchronization with each other by the input of the driving force from the main motor 13, and the printing units 4A, 4B, 4C, 4D. The phase relationship of the plate cylinder 5 is set so that the patterns of the colors by the printing units 4A, 4B, 4C, and 4D overlap in the same area on the paper 2, and thus the colors are overlapped on the same area. As a result, a desired multicolor pattern is formed.

  The paper 2 that has finished printing in the printing unit 4 is heated and dried in the dryer unit of the next process, and then cooled in the cooling cylinder unit. Then, the paper 2 that has been dried and cooled is transferred to a folding machine, and is cut into a predetermined area in units of a pattern printed by the printing unit 4. The cut sheet 2 is folded by a folding roller, a chopper folding device, or the like to be formed into a target fold, and is transported to the outside as a printed product as a final product.

  In this printing machine, the printing density is controlled by controlling the rotation speed of the ink source roller 20 according to the printing speed by the ink supply control device 50 according to the method described below.

  That is, as described above, a general printing machine stores a map (speed function map) showing the relationship between the printing speed and the ink source roller rotation speed as indicated by 17 in FIG. 4 in the ink supply control device, The rotation speed of the ink base roller is controlled according to this speed function map. However, in this speed function map, as described above, since a large number of ink rollers are interposed from the ink source roller to the plate cylinder on which the printing plate is mounted, changes in the rotation speed of the ink source roller are transferred to the sheet. Since there is a considerable delay time until the change in ink density is reflected, when the rotation speed of the ink source roller is changed in advance, the time required to reach the ink density corresponding to the changed rotation speed is examined. A new acceleration speed function map 51 is prepared as the relationship between the time during acceleration from the adjustment speed to the business operation speed and the rotation speed of the ink source roller.

  When the printing speed is a constant speed of the adjustment speed or the business operation speed, the ink source motor 21 is controlled according to the conventional speed function map 17 so that the rotation speed of the ink source roller 20 is set to a constant speed according to the printing speed. On the other hand, when accelerating from the adjustment speed to the business operation speed, the ink source motor 21 is controlled according to the new speed function map 51 to change the rotation speed of the ink source roller 20 according to time. .

  Also in this case, as described with reference to FIG. 3, the time until the density of ink transferred from the blanket cylinder to the paper changes after changing the rotation speed of the ink base roller (feed forward control). As the pattern area ratio increases, the change rate increases and changes in a short time. If the pattern area ratio is small, the change rate decreases and the change takes a long time. For example, as shown in FIG. 4 from large to small pattern area ratio, a plurality of patterns corresponding to the pattern area ratio are prepared, the pattern area ratio of the pattern to be printed in advance is examined, and an acceleration speed function map corresponding to the area ratio is prepared. 51 is used.

  The time chart of FIG. 5 shows the effect in such a case, FIG. 5 (a) shows the state at the time of acceleration from the adjustment speed of the printing press to the commercial operation speed, and FIG. 5 (b) shows the ink origin. FIG. 5 (c) shows the change in the rotation speed of the roller. FIG. 5 (c) shows the change in the printing density. The alternate long and short dash line is the control characteristic in the range where the pattern area ratio is large, and the broken line is the control characteristic based on the conventional constant speed speed function map 17.

  The pattern area ratio is divided into, for example, three ranges of large, medium, and small, and the control characteristics of the rotational speed of the ink source roller 20 in each range are controlled by the conventional constant speed function map 17 (no predictive control). As shown in FIG. 5B, when the pattern area ratio is small, the rotational speed of the ink base roller 20 is set higher and the predictive control start time precedes the print speed acceleration start time. In addition, the prediction control end time is delayed from the printing speed acceleration end time. Further, when the pattern area ratio is large, the rotation speed of the ink base roller 20 is set to be lower and the prediction control start time is set. The printing speed acceleration is close to the start time, and the prediction control end time is also close to the print speed acceleration end time.

  By doing so, as shown in FIG. 5 (c), which compares the change in printing density when the rotation speed of the ink base roller 20 is changed with each control characteristic, the average of the pattern for the current printing is shown. When the pattern area ratio is relatively small as indicated by the solid line, the rotational speed of the ink base roller 20 is set to a higher value so that the prediction control start time precedes the printing speed acceleration start time, and the prediction control ends. The point of time is delayed from the end of acceleration of printing speed, so that the change in ink density is within the allowable range, and the two-point difference is applied when the pattern area ratio is medium although the prediction control is performed and the broken line is not used. Compared to the case of the line, the rate of change is made smaller. Therefore, by changing the rotation speed of the ink source roller 20 with the control characteristic that matches the average pattern area ratio of the pattern for the current printing, the change in the printing density accompanying the acceleration can be more reliably within the allowable range. It becomes possible.

JP 2003-276165 A

  However, the printing density control method of the printing machine disclosed in Patent Document 1 is also good for a printed matter having a uniform print area ratio on the front surface, but in a general commercial printed matter, the pattern distribution of the printed matter is about 20%. However, it is difficult to uniquely determine such feedforward control time. Therefore, if the feedforward control time is controlled by a certain pattern area ratio, the picture area far apart from the set picture area In the ink key zone of the rate, the ink density does not fall within the allowable density range, and a waste paper is generated.

  For this reason, in the present invention, the rotation speed change of the ink source roller accompanying the acceleration from the adjustment speed of the printing press speed to the business operation speed at the start of operation can be performed so that the ink density always remains within the allowable density range. It is an object to provide a printing machine capable of preventing the occurrence.

In order to solve the above problems, a printing density control method for a printing press according to the present invention is as follows.
The printing speed in a printing machine that supplies ink to the plate cylinder from the ink supply device via a plurality of ink rollers is changed from a first speed to a second speed different from the first speed according to a predetermined speed change characteristic. Is a method for controlling a change in print density, predicting a change in print density when the printing speed is changed according to the shift characteristic, and determining a change in print density based on the predicted print density change characteristic. The ink supply control characteristic of the ink supply device for canceling is set in advance, and during a predetermined period from the predetermined time before the start of changing the printing speed to the predetermined time after the end of the change, according to the ink supply control characteristic set in advance. In a printing density control method for a printing press in which the amount of ink supplied from the ink supply device is changed,
In the ink supply device, the ink supply roller constituting the ink supply device is divided into a plurality of predetermined areas, and the ink supply control characteristics of the ink supply device set in advance to cancel the change in the printing density are set as the pattern area of the printed matter. Prepare several according to the rate,
A pattern area ratio of a printed matter is calculated for each of the predetermined areas of the divided ink base roller, and an ink supply characteristic prepared corresponding to the pattern area ratio is applied to each of the calculated pattern area ratios, and the ink The amount of ink supplied from the ink supply device is changed for each of the divided predetermined areas of the original roller.

And the printing machine which implements the printing density control method of this printing machine,
An ink supply device for supplying ink to a plate cylinder in a printing machine via a plurality of ink rollers; a printing speed control means for changing a printing speed from a first speed to a second speed according to a predetermined speed change characteristic; Predicting the characteristics of the change in print density when the printing speed is changed according to the characteristics, and presetting the ink supply control characteristic of the ink supply device for canceling the change in the print density based on the predicted print density change characteristic Storage means, and ink supply control means for controlling the ink supply amount of the ink supply device, the ink supply control means being changed from a predetermined time before the start of changing the printing speed by the printing speed control means. During a predetermined period until the predetermined time after the completion, the amount of ink supplied from the ink supply device is determined according to the ink supply control characteristics stored in the storage means. The printing machine for controlling to gradually by reduction,
The ink supply roller constituting the ink supply device is divided into a plurality of predetermined areas, and the ink supply control characteristics of the ink supply device stored in the storage means are prepared in correspondence with the pattern area ratio of the printed matter,
The ink supply control unit includes a unit that calculates a pattern area ratio of a printed material for each division range of the ink base roller that is divided for each predetermined region, and for each pattern area ratio calculated by the calculation unit, the pattern An ink supply characteristic prepared in correspondence with an area ratio is applied, and the amount of ink supplied from the ink supply device is controlled to be changed for each ink source roller divided for each predetermined region. .

  An ink supply characteristic prepared corresponding to the pattern area ratio is set as a control characteristic of the rotation speed of the ink source roller with respect to time, and the ink source is controlled according to the rotation speed control characteristic during the predetermined period. The ink source roller that changes the rotation speed of the roller and is divided for each predetermined region has an ink source motor that is a drive source provided corresponding to each divided ink source roller, and The ink supply control means controls the change in the amount of ink supplied from the ink supply device by changing the driving speed of the ink source motor.

  In addition, the printing density change characteristic when the printing speed is changed according to the shift characteristic is predicted for each specific printing condition that affects the printing density change characteristic, and the ink supply control characteristic is previously set for each printing condition. During the predetermined period, an ink supply control characteristic corresponding to the printing conditions for the current printing is selected from a plurality of preset ink supply control characteristics, and the ink is selected according to the selected ink supply control characteristic. It is characterized in that the amount of ink supplied from the supply device is changed.

  Furthermore, the printing conditions include a paper type and / or an ink type.

  As described above, the ink supply roller constituting the ink supply device is divided into a plurality of predetermined areas, and a plurality of ink supply control characteristics of the ink supply device are prepared in correspondence with the pattern area ratio of the printed material. Means for calculating the pattern area ratio of the printed matter for each divided range, and the ink supply control means prepares ink corresponding to the pattern area ratio for each pattern area ratio calculated for each of the divided predetermined areas. By applying supply characteristics and changing the amount of ink supplied from the ink supply device for each predetermined area, for example, the pattern distribution of the printed material is not uniform, so the pattern area ratio is in the axial direction of the ink source roller. Even if they are different, the ink supply can be changed correspondingly. The rotational speed variation of the fountain roller, always ink density is possible to perform still allowable concentration range, it is possible to provide a print density control method and a printing press of the printing press can be prevented broke.

  An ink supply characteristic prepared corresponding to the pattern area ratio is set as a control characteristic of the rotation speed of the ink source roller with respect to time, and the ink source is controlled according to the rotation speed control characteristic during the predetermined period. The ink source roller divided for each predetermined area is driven by an ink source motor provided corresponding to each divided ink source roller by changing the rotation speed of the roller, and the ink source roller is divided. The ink amount supplied from the supply device can be changed by changing the driving speed of the ink source motor, and the ink supply amount can be changed very easily.

  In addition, the printing density change characteristic when the printing speed is changed according to the shift characteristic is predicted for each specific printing condition that affects the printing density change characteristic, and the ink supply control characteristic is previously set for each printing condition. During the predetermined period, an ink supply control characteristic corresponding to the printing conditions for the current printing is selected from a plurality of preset ink supply control characteristics, and the ink is selected according to the selected ink supply control characteristic. By changing the amount of ink supplied from the supply device, the amount of ink supplied can be changed more appropriately.

  Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention unless otherwise specified, but are merely illustrative examples. Not too much.

  FIG. 1A is a schematic diagram showing the configuration of a printing machine that performs a printing density control method according to the present invention, FIG. 1B is a specific example of an ink source roller and an ink source motor, and FIG. 2 is a printing density according to the present invention. It is a graph which shows the time chart of a control method.

In the figure, the same constituent elements as those in the conventional example shown in FIG. 4 are denoted by the same reference numerals, 1 being a roll of paper 2, 3 being an infeed unit, 4 being black (K), cyan (C ), Magenta (M), yellow (Y), and other printing units 4A, 4B, 4C, 4D corresponding to the respective colors, 5 is a plate cylinder, 6 is a blanket cylinder, 13 is each printing unit 4A, 4B, A main motor for transmitting driving force to a main shaft 13a for driving 4C and 4D, 17 is a speed function map, 19 is an ink key, 30 is an ink source roller, and this ink source roller 30 is shown in FIG. As shown, the ink source motor 31 is divided into predetermined areas ₁ , 30 ₂ ,... 30 _n of 30 ₁ , 30 ₂ ,... 30 _n , and the ink source motor 31 is divided into areas 1 (30 ₁ ), region 2 ₍₃₀ 2) _{...... M 1 31 1, M 2} 31 2 corresponding to the respective regions _{n (30 n), ...... M} n 31 n is made to be driven by each provided individual speed. 25 is a printing speed control device, 501 is an ink supply control device, 51 shown as large to small is a speed function map for acceleration prepared for each pattern area ratio, 52 is a database storing the speed function map 51 for acceleration, 53 is an input unit for inputting a pattern area ratio and the like, 54 is each area 1 (30 ₁ ) of the ink fountain roller divided into predetermined areas based on the pattern area ratio information of the printed pattern input from the input unit 53, and the area 2 (30 ₂ )... The pattern area ratio for each area on the printed matter corresponding to the width of each area n (30 _n ) is calculated, and the acceleration speed function map 52 corresponding to the pattern area ratio is selected. The feed forward control time calculation device controls the speed of the ink source motors M ₁ 31 ₁ , M ₂ 31 ₂ ,..., M _n 31 _{n at} the speed indicated in the map.

  As described above, the paper 2 used for printing is set in the infeed unit 3 in the form of a roll-shaped web 1. The infeed unit 3 includes an infeed drag (not shown) that sandwiches and rotates the paper 2 and a dancer roller that appropriately controls the tension of the paper 2. The infeed drag is a main motor driven by a main motor 13. It is connected to the shaft 13a so that the rotational driving force from the main motor 13 is transmitted through the main shaft 13a.

  The paper 2 drawn out from the web 1 by the infeed unit 3 is printed by the four printing units 4A, 4B, 4C, and 4D in the printing unit 4, and each of the printing units 4A, 4B, 4C, and 4D includes An ink supply device for supplying ink is provided. The ink supply device has an ink base roller 30 and a plurality of ink keys 19 arranged in parallel in the axial direction of the ink base roller 30, and a container formed by the ink base roller 30 and the ink key 19 serves as an ink fountain for storing ink. It has become. The amount of ink supplied from the ink fountain can be controlled by the rotational speed of the ink base roller 30 and the opening of the gap between the ink key 19 and the ink base roller 30 (ink key opening). The supplied ink is supplied to the plate cylinder 5 while being appropriately kneaded by a number of ink rollers (not shown), and further transferred from the plate cylinder 5 to the paper 2 via the blanket cylinder 6. Each of the printing units 4A, 4B, 4C, 4D is connected to the main shaft 13a and rotates in synchronization with each other by the input of the driving force from the main motor 13, and the printing units 4A, 4B, 4C, 4D. The phase relationship of the plate cylinder 5 is set so that the patterns of the colors by the printing units 4A, 4B, 4C, and 4D overlap in the same area on the paper 2, and thus the colors are overlapped on the same area. As a result, a desired multicolor pattern is formed.

  The paper 2 that has finished printing in the printing unit 4 is heated and dried in the dryer unit of the next process, and then cooled in the cooling cylinder unit. Then, the paper 2 that has been dried and cooled is transferred to a folding machine, and is cut into a predetermined area in units of a pattern printed by the printing unit 4. The cut sheet 2 is folded by a folding roller, a chopper folding device, or the like to be formed into a target fold, and is carried out to the outside as a printed product as a final product.

In the printing press according to the present invention configured as described above, the ink source roller 30 includes the predetermined areas 1, 30, 30 _n of 30 ₁ , 30 ₂ ,... 30 _n as shown in FIG. Ink source motor M ₁ 31 ₁ is divided into areas n, corresponding to areas 1 (30 ₁ ), 2 (30 ₂ ),..., Area n (30 _n ) of the divided ink source rollers. , M ₂ 31 ₂ ,... M _n 31 _n are provided so that they can be driven at individual speeds.

  On the other hand, in the database 52 of the ink supply control device 501, when the rotational speed of the ink base roller 30 is changed in advance, the ink density of the plate cylinder 5 is adjusted to the ink density corresponding to the changed rotational speed in advance. An acceleration speed function map 51 is prepared for each specific pattern area ratio in the printed matter. The acceleration speed function map 51 is a relation between the time during acceleration from the adjustment speed to the business operation speed and the rotation speed of the ink source roller 30.

  That is, as described with reference to FIG. 3, the time from when the rotation speed of the ink base roller is changed until the ink density transferred from the blanket cylinder 6 to the paper is changed (feed forward control time) is the pattern. As the area ratio increases, the rate of change increases and changes in a short time. When the pattern area rate is small, the rate of change decreases and the change takes a long time. As shown from a large pattern area ratio to a small pattern area, a plurality of pattern area ratios are prepared.

  In the printing press according to the present invention configured as described above, when the printing press is operated at a constant speed such as an adjustment speed and a business operation speed, each region feedforward control time calculation device 54 is indicated by 17 in FIG. The ink source motor 31 is controlled using the speed function map, and the rotation speed of the ink source roller 30 is controlled to a constant speed corresponding to the printing speed.

Then, when accelerating from the adjustment speed for changing the printing plate and adjusting the registration and color tone to the business operation speed, each area feedforward control time calculation device 54 in the ink supply control device 501 is the print speed control device 25. When a printing speed signal indicating that acceleration is to be performed from now on, in order to switch the control from the speed function map 17 to the speed function map 51 for acceleration, first, a printing plate that is input from the input unit 53, for example, upstream and is printed this time. The pattern of the printed matter corresponding to each of the areas 1 (30 ₁ ), 2 (30 ₂ ),..., Area n (30 _n ) of the divided ink source roller using the pattern area ratio information included in the data for use. The area ratio is calculated.

  Note that the pattern area ratio information for calculating the average pattern area ratio can be acquired online from an upstream plate making process or via a recording medium. In the case of online input, the pattern area ratio information is input. The input unit 53 corresponds to a transmission / reception interface, and in the case of input using a recording medium, the input unit 53 corresponds to a recording medium reading device. Of course, the operator may input the average picture area ratio manually.

Further, each region feedforward control time calculation device 54 corresponds to the calculated pattern area ratio for each region 1 (30 ₁ ), region 2 (30 ₂ ),..., Region n (30 _n ). The acceleration speed function map 51 is selected.

Thus, when the acceleration speed function map 51 is selected for each region 1 (30 ₁ ), region 2 (30 ₂ ),... Region n (30 _n ) of the ink source roller, each region feedforward control time is next. The computing device 54 follows the time-ink source roller rotation speed specified by the acceleration speed function map 51, for example, at each of the ink source motors M ₁ 31 ₁ , Tn shown in FIG. M ₂ 31 ₂ ,... M _n 31 _n , feed forward control is performed prior to the start of printing press acceleration, and then control is performed so that acceleration of the main motor 13 is started. Will be sent.

By doing so, the ink source roller 30 divided into each region 1 (30 ₁ ), region 2 (30 ₂ ),... Region n (30 _n ) is suitable for the pattern area ratio in each region. Since the ink is fed out at a rotational speed, even in a printed matter that occupies about 20% in a general commercial printed matter and the pattern distribution of the printed matter is not uniform, as shown by the solid line in FIG. Acceleration can be performed while remaining in the range, and it is possible to prevent generation of waste paper during that time.

  In addition, what has been described above is a control method in the case of accelerating at the start of operation, and when operating the printing press at a constant speed such as an adjustment speed and a business operation speed, each region feedforward control time calculation device 54 The ink source motor 31 is controlled using the speed function map indicated by 17 in FIG. 4, and the rotation speed of the ink source roller 30 is controlled to a constant speed corresponding to the printing speed, as in the conventional case.

  In the above description, the case where the change characteristic of the print density at the time of acceleration is controlled by the pattern area ratio has been described, but the change characteristic of the print density at the time of acceleration also changes depending on the paper type and the ink type. That is, since the printing density varies depending on the paper type and ink type even with the same ink amount, an acceleration speed function map (ink supply control characteristic) is set for each paper type and ink type and stored in the database 52. When accelerating, an acceleration speed function map corresponding to the paper type and ink type for the current printing may be selected from the database. The input of the paper type and the ink type to the ink supply control device may be manual input by an operator, or may be automatic input online from an upstream plate making process.

  In addition, if the printing conditions (paper type, ink type) for this printing are new conditions and the corresponding acceleration speed function map does not exist in the database, for example, for unknown paper types, including the basis weight A known paper type closest to the paper type is selected, and the rotational speed of the ink source roller is controlled using an acceleration speed function map for the known paper type. Alternatively, the physical properties of the paper vary greatly depending on the presence or absence of the coat layer, so the categories are divided by the presence or absence of the coat layer (coated paper or uncoated paper), and at least two known categories belonging to the unknown paper type belong to The paper type may be selected. In this case, the acceleration speed function map for the selected at least two known paper types is used to interpolate the acceleration speed function map corresponding to the paper type for the current printing.

  Further, the application of the present invention is not limited only to printing density control during acceleration as in the above-described embodiment. For example, the print density control of the present invention can be applied even during deceleration from the printing speed to the stop. Furthermore, the present invention can be applied not only to a shift at a constant change rate but also to a shift with a more complicated shift pattern (shift characteristic). In other words, even if the shift pattern is complex, if the shift pattern is the same, the pattern of change in print density (print density change characteristic) is the same, and the ink supply control characteristic is based on the print density change pattern. By setting, it becomes possible to suppress a change in print density accompanying a change in printing speed.

  Furthermore, the printing press to which the present invention is applied is not limited to the configuration of the above-described embodiment. For example, the present invention can be applied not only to a shaft drive type rotary printing press as shown in the embodiment but also to a shaftless type rotary printing press provided with a drive motor for each printing unit. The printing density control method of the present invention is also effective when applied to a sheet-fed printing press. Even in a sheet-fed printing press, since a plurality of rollers are interposed from the ink source roller to the plate surface, there is a possibility that the print density may fluctuate while the printing speed is changed due to a delay in following the amount of ink supplied to the plate surface. . Therefore, by applying the print density control method of the present invention, it is possible to suppress the change in the print density accompanying the change in the printing speed and reduce the waste paper.

  Further, the same applies to the configuration of the ink supply device, and the printing machine to which the present invention is applied is not limited to the configuration including the ink source roller and the ink key as in the above-described embodiment. That is, as long as a plurality of ink rollers are interposed between the ink supply device and the plate cylinder, the configuration of the ink supply device is not limited. For example, it is a printing machine having an ink rail as an ink supply device. May be.

  As described above, the ink supply roller constituting the ink supply device is divided into a plurality of predetermined areas, and a plurality of ink supply control characteristics of the ink supply device are prepared in correspondence with the pattern area ratio of the printed matter. Means for calculating the pattern area ratio of the printed matter is provided for each division range of the ink source roller, and the ink supply control means causes the pattern area ratio calculated for each of the divided predetermined areas to correspond to the pattern area ratio. By applying the ink supply characteristics prepared in advance and changing the amount of ink supplied from the ink supply device for each predetermined area, for example, the pattern distribution of the printed matter is not uniform, so the pattern area ratio is the ink source roller Even if they differ in the axial direction of the ink, the ink supply amount can be changed correspondingly, so that the adjustment speed of the printing press at the start of operation is added to the operating speed of operation. It is possible to provide a printing density control method and a printing press for a printing press capable of preventing the occurrence of damaged paper by allowing the ink density to always change within the allowable density range for the rotation speed change of the ink base roller accompanying the it can.

  An ink supply characteristic prepared in correspondence with the pattern area ratio is set as a control characteristic of the rotation speed of the ink source roller with respect to time, and the ink source according to the rotation speed control characteristic during the predetermined period. The ink source roller divided for each predetermined area is driven by an ink source motor provided corresponding to each divided ink source roller by changing the rotation speed of the roller, and the ink source roller is divided. The ink amount supplied from the supply device can be changed by changing the driving speed of the ink source motor, and the ink supply amount can be changed very easily.

  In addition, the printing density change characteristic when the printing speed is changed according to the shift characteristic is predicted for each specific printing condition that affects the printing density change characteristic, and the ink supply control characteristic is previously set for each printing condition. During the predetermined period, an ink supply control characteristic corresponding to the printing conditions for the current printing is selected from a plurality of preset ink supply control characteristics, and the ink is selected according to the selected ink supply control characteristic. By changing the amount of ink supplied from the supply device, the amount of ink supplied can be changed more appropriately.

  According to the present invention, it is possible to effectively suppress a change in print density by changing the amount of ink supplied from the ink supply device according to the ink supply control characteristic set according to the print density change characteristic at the time of speed change. As a result, it is possible to provide a printing machine and a printing density control method for the printing machine that can prevent generation of damaged paper accompanying a change in printing speed.

It is the schematic which shows the structure of the printing machine which implements the printing density control method which becomes this invention. It is a time chart of the printing density control method which becomes this invention. It is a graph which shows the relationship between the pattern area rate in printed matter, and feedforward control time. It is the schematic which shows the structure of the printing machine which implements the conventional printing density control method. It is a time chart for explaining the contents of conventional printing density control, (a) is a time chart showing the speed change from the adjustment speed to the business operation speed, (b) shows the change of the rotation speed of the ink source roller. (C) is a time chart showing a change in printing density.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Roll-shaped winding paper 2 Paper 3 In-feed part 4 Printing part 4A, 4B, 4C, 4D Printing unit 5 Plate cylinder 6 Blanket cylinder 13 Main motor 13a Main shaft 17 Speed function map 19 Ink key 30 Ink original roller 30 ₁ , 30 ₂ , ... 30 _n ink source roller area 1, area 2, ... area n
31 the ink fountain motor _{31 1, 31 2, ...... M} n 31 n ink fountain motor _{M 1, M 2, ...... M} n
25 Printing Speed Control Device 501 Ink Supply Control Device 51 Acceleration Speed Function Map 52 Database 53 Input Unit 54 Each Area Feedforward Control Time Calculation Device

Claims (6)

The printing speed in a printing machine that supplies ink to the plate cylinder from the ink supply device via a plurality of ink rollers is changed from a first speed to a second speed different from the first speed according to a predetermined speed change characteristic. Is a method for controlling a change in print density, predicting a change in print density when the printing speed is changed according to the shift characteristic, and determining a change in print density based on the predicted print density change characteristic. The ink supply control characteristic of the ink supply device for canceling is set in advance, and during a predetermined period from the predetermined time before the start of changing the printing speed to the predetermined time after the end of the change, according to the ink supply control characteristic set in advance. In a printing density control method for a printing press in which the amount of ink supplied from the ink supply device is changed,
In the ink supply device, the ink supply roller constituting the ink supply device is divided into a plurality of predetermined areas, and the ink supply control characteristics of the ink supply device set in advance to cancel the change in the printing density are set as the pattern area of the printed matter. Prepare several according to the rate,
A pattern area ratio of a printed matter is calculated for each of the predetermined areas of the divided ink base roller, and an ink supply characteristic prepared corresponding to the pattern area ratio is applied to each of the calculated pattern area ratios, and the ink A printing density control method for a printing press, wherein the amount of ink supplied from the ink supply device is changed for each of the predetermined areas of the original roller.   An ink supply characteristic prepared in correspondence with the pattern area ratio is set as a control characteristic of the rotation speed of the ink fountain roller with respect to time, and during the predetermined period, the ink fountain roller according to the rotation speed control characteristic is set. 2. The printing density control method for a printing press according to claim 1, wherein the rotation speed is changed.   A characteristic of a change in print density when a printing speed is changed according to the speed change characteristic is predicted for each specific printing condition that affects the print density change characteristic, and the ink supply control characteristic is preset for each printing condition. In addition, during the predetermined period, an ink supply control characteristic corresponding to the printing conditions for the current printing is selected from a plurality of preset ink supply control characteristics, and the ink supply device is selected according to the selected ink supply control characteristic. 2. The printing density control method for a printing press according to claim 1, wherein the amount of ink supplied from the printer is changed.   The printing density control method for a printing press according to claim 3, wherein the printing conditions include paper type and / or ink type. An ink supply device for supplying ink to a plate cylinder in a printing machine via a plurality of ink rollers; a printing speed control means for changing a printing speed from a first speed to a second speed according to a predetermined speed change characteristic; Predicting the characteristics of the change in print density when the printing speed is changed according to the characteristics, and presetting the ink supply control characteristic of the ink supply device for canceling the change in the print density based on the predicted print density change characteristic Storage means, and ink supply control means for controlling the ink supply amount of the ink supply device, the ink supply control means being changed from a predetermined time before the start of changing the printing speed by the printing speed control means. During a predetermined period until the predetermined time after the completion, the amount of ink supplied from the ink supply device is determined according to the ink supply control characteristics stored in the storage means. The printing machine for controlling to gradually by reduction,
The ink supply roller constituting the ink supply device is divided into a plurality of predetermined areas, and the ink supply control characteristics of the ink supply device stored in the storage means are prepared in correspondence with the pattern area ratio of the printed matter,
The ink supply control unit includes a unit that calculates a pattern area ratio of a printed material for each division range of the ink base roller that is divided for each predetermined region, and for each pattern area ratio calculated by the calculation unit, the pattern An ink supply characteristic prepared in correspondence with an area ratio is applied, and the amount of ink supplied from the ink supply device is controlled to be changed for each ink source roller divided for each predetermined region. Printer.   The ink fountain roller divided for each predetermined area has an ink fountain motor as a drive source provided corresponding to each divided ink fountain roller, and is supplied from an ink supply device by the ink supply control means. 6. The printing press according to claim 5, wherein the change in the amount of ink to be controlled is controlled by changing the drive speed of the ink source motor.

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