JP2017209794A - Multicolor printing system and control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology that can reduce an influence on mis-register that is caused by variation in web transportation speed.SOLUTION: A multicolor printing system prints on a web by a plurality of plate cylinders. The multicolor printing system includes: a determination part 55 for determining whether web transportation speed varies or not; and a registration alignment part 57 controlling the plurality of plate cylinders so as to prevent any shifting in a printing pattern printed on the web by the plurality of plate cylinders depending on determination result by the determination part 55.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a multicolor printing system and a control method.

  There is known a multicolor printing system in which a plurality of printing units are installed along a web conveyance path, a plate cylinder provided in each printing unit is individually driven to rotate, and printing is sequentially performed on the web. In a multicolor printing system, the registration mark printed on the web is detected, and the amount of misregistration between the plate cylinders (registration deviation amount) is calculated based on the detection result, so that the registration cylinder is corrected. Control the drive motor.

Japanese Patent Laid-Open No. 08-052865

  In a multicolor printing system, when the web conveyance speed (that is, the printing speed) is changed, the web tension varies depending on the moment of inertia of the free roll between the plate cylinders. Misregistration can occur when the tension varies.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a technique capable of reducing the influence of a change in web conveyance speed on misregistration.

  In order to solve the above problems, a multicolor printing system according to an aspect of the present invention is a multicolor printing system that prints on a web using a plurality of plate cylinders, and determines whether or not the web conveyance speed has changed. And a matching unit that controls the plurality of plate cylinders so as not to cause a shift in a printing pattern printed on the web by the plurality of plate cylinders according to a determination result by the determination unit.

  Another aspect of the present invention is a control method. This method is a method that is executed in a multicolor printing system that prints on a web with a plurality of plate cylinders. The method determines whether or not the web conveyance speed has changed, and a plurality of times depending on the determination result. Controlling a plurality of plate cylinders so that a printing pattern printed on the web by the plate cylinders does not shift.

  Note that any combination of the above-described constituent elements, and those obtained by replacing the constituent elements and expressions of the present invention with each other among methods, apparatuses, systems, etc. are also effective as an aspect of the present invention.

  ADVANTAGE OF THE INVENTION According to this invention, the influence which the change of the conveyance speed of a web has on a registration gap can be reduced.

1 is a diagram illustrating a configuration of a multicolor printing system according to an embodiment. It is a block diagram which shows the function and structure of the register control unit of FIG.

  Hereinafter, the same or equivalent components, members, and processes shown in the drawings are denoted by the same reference numerals, and repeated descriptions are appropriately omitted. In addition, the dimensions of the members in each drawing are appropriately enlarged or reduced for easy understanding. Also, in the drawings, some of the members that are not important for describing the embodiment are omitted.

  FIG. 1 shows a configuration of a multicolor printing system 100 according to the embodiment. The multicolor printing system 100 includes a first printing unit 10A, a second printing unit 10B, a third printing unit 10C, a fourth printing unit 10D (hereinafter also collectively referred to as “printing unit 10”), and a plurality of free rolls 20. And a register control unit 30.

  The web 2 is unwound from an unwinding roll (not shown) by an infeed roll (not shown), guided to a free roll 20 and conveyed in a predetermined direction, and taken up by a winding roll (not shown). The first printing unit 10A, the second printing unit 10B, the third printing unit 10C, and the fourth printing unit 10D are installed in this order along the conveyance direction of the web 2.

  The first printing unit 10A includes a plate cylinder 11A, an impression cylinder 12A, and a drive motor 13A. The plate cylinder 11A is pressed against the web 2 by the impression cylinder 12A. The web 2 is printed with a color printing pattern and a registration mark corresponding to the plate cylinder 11A. The drive motor 13A rotates the plate cylinder 11A.

  The second printing unit 10B includes a plate cylinder 11B, an impression cylinder 12B, and a drive motor 13B. The third printing unit 10C includes a plate cylinder 11C, an impression cylinder 12C, and a drive motor 13C. The fourth printing unit 10D includes a plate cylinder 11D, an impression cylinder 12D, and a drive motor 13D.

  The plate cylinder 11B, the plate cylinder 11C, and the plate cylinder 11D are each configured similarly to the plate cylinder 11A. Each of the impression cylinder 12B, the impression cylinder 12C, and the impression cylinder 12D is configured similarly to the impression cylinder 12A. The drive motor 13B, the drive motor 13C, and the drive motor 13D are each configured similarly to the drive motor 13A. The multicolor printing system 100 is a sectional drive type printing system in which each plate cylinder is driven by an individual drive motor.

  Hereinafter, the plate cylinder 11A, the plate cylinder 11B, the plate cylinder 11C, and the plate cylinder 11D are collectively referred to as the plate cylinder 11 as well. The impression cylinder 12A, impression cylinder 12B, impression cylinder 12C, and impression cylinder 12D are also collectively referred to as the impression cylinder 12. The drive motor 13A, the drive motor 13B, the drive motor 13C, and the drive motor 13D are also collectively referred to as the drive motor 13. The registration marks printed by the first printing unit 10A, the second printing unit 10B, the third printing unit 10C, and the fourth printing unit 10D are respectively the first registration mark, the second registration mark, the third registration mark, and the first registration mark. Called the 4 register mark.

  The register control unit 30 includes a mark sensor 40B, a mark sensor 40C, a mark sensor 40D (hereinafter also collectively referred to as “mark sensor 40”), a speed detector 42, a plurality of tension detectors 44, and a control device 50. And including.

  The speed detector 42 detects the conveyance speed (that is, the printing speed) of the web 2 at a predetermined period (for example, one second period). The speed detector 42 may detect the conveyance speed of the web 2 by detecting the rotation speed of the infeed roll.

  The plurality of tension detectors 44 detect the tension of the web 2 between the plate cylinders at a predetermined period (for example, one second period). As the tension detector, one using a differential transformer or a load cell is generally used, but since the tension detector is known, it will not be described in detail here.

  The mark sensor 40B is provided on the downstream side of the second printing unit 10B. The mark sensor 40B includes an upstream first photodetecting element T1 and a downstream second photodetecting element T2. The first photodetecting element T1 and the second photodetecting element T2 are arranged at an interval L. The interval L corresponds to the distance between the first register mark and the second register mark when there is no misregistration. Therefore, if the first registration mark and the second registration mark are printed at regular intervals at an interval L, they are detected at substantially the same timing by the first light detection element T1 and the second light detection element T2. .

  Each of the mark sensor 40C and the mark sensor 40D is configured similarly to the mark sensor 40B. If the second registration mark and the third registration mark are printed at regular intervals at an interval L, detection is performed at substantially the same timing by the first light detection element T1 and the second light detection element T2 of the mark sensor 40C. Is done. Further, if the third register mark and the fourth register mark are printed at regular intervals at the interval L, the first photodetecting element T1 and the second photodetecting element T2 of the mark sensor 40D have substantially the same timing. Is detected.

  FIG. 2 is a block diagram illustrating the function and configuration of the control device 50. Each block shown here can be realized by hardware such as a computer (CPU) (central processing unit) and other elements and mechanical devices, and software can be realized by a computer program or the like. Here, The functional block realized by those cooperation is drawn. Therefore, it is understood by those skilled in the art who have touched this specification that these functional blocks can be realized in various forms by a combination of hardware and software.

  The control device 50 includes a registration mark detection unit 51, a registration deviation amount calculation unit 52, an acceleration calculation unit 54, a determination unit 55, a tendency prediction unit 56, and a matching unit 57. The registration mark detection unit 51 detects a registration mark attached to the web 2 based on a signal output from the mark sensor 40.

  A detection result by the registration mark detection unit 51 is input to the registration deviation amount calculation unit 52. The registration deviation amount calculation unit 52 calculates the deviation amount of the printing position between the printing units, that is, the registration deviation amount based on the detection result. Specifically, for example, the first registration mark and the second registration mark when there is no misregistration are printed at an interval L. Further, as described above, the first photodetecting element T1 and the second photodetecting element T2 of the mark sensor 40B are also arranged at the interval L. Therefore, when there is no misregistration, the first register mark and the second register mark are detected at substantially the same timing. On the other hand, when there is a misregistration, the first register mark and the second register mark are detected at different timings. The registration deviation amount calculation unit 52 calculates a value obtained by multiplying the difference in detection timing by the conveyance speed of the web 2 as a registration deviation amount.

  In order to change the printing speed, the rotational speed of the in-feed roll may be accelerated or decelerated (hereinafter collectively referred to as “acceleration / deceleration”), and the conveyance speed of the web 2 may be accelerated / decelerated. The acceleration calculation unit 54 calculates the acceleration of the conveyance speed of the web 2 by differentiating the conveyance speed of the web 2 obtained from the speed detector 42.

  The determination unit 55 determines whether or not the conveyance speed of the web 2 is accelerating / decelerating, that is, whether or not the conveyance speed of the web 2 is changing. When the acceleration calculated by the acceleration calculation unit 54 is a positive value, the determination unit 55 determines that the conveyance speed of the web 2 is accelerating. When the acceleration calculated by the acceleration calculation unit 54 is a negative value, 2 is decelerated, and the acceleration calculated by the acceleration calculator 54 is substantially zero, the web 2 is not accelerated or decelerated (that is, the conveyance speed is constant). ).

  The trend predicting unit 56 predicts a change trend of the conveyance speed of the web 2. In the present embodiment, the trend prediction unit 56 calculates the differential value of the acceleration calculated by the acceleration calculation unit 54 as a predicted value.

  The matching unit 57 controls each plate cylinder 11 so that the printing pattern printed on the web 2 by each plate cylinder 11 of each printing unit 10 does not shift.

  First, the matching unit 57 determines the initial phase of each plate cylinder based on the circumference of the plate cylinder and the path length between the plate cylinders. Here, if the path length from the printing point P of the plate cylinder 11A to the printing point P of the plate cylinder 11B is an integral multiple of the circumference of the plate cylinder 11, the plate cylinder 11A and the plate cylinder 11B are in phase. There is no misregistration between them. On the other hand, if it is not an integral multiple, if the plate cylinder 11A and the plate cylinder 11B are in the same phase, there is a misregistration by the remainder obtained by dividing the path length by the circumference. The same applies to the plate cylinder 11B and the plate cylinder 11C, and the plate cylinder 11C and the plate cylinder 11D. In consideration of these, the matching unit 57 determines the initial phase of each plate cylinder so that there is no registration error. Since the technique for determining the initial phase is well known, further explanation is omitted.

  Further, when there is a misregistration between printing units, that is, when a misregistration is calculated by the misregistration amount calculation unit 52, the registering unit 57 controls the plate cylinder 11 to reduce the misregistration.

  Here, when the phase of the plate cylinder 11 is manipulated to reduce misregistration, the tension of the web 2 before and after the plate cylinder 11 varies. Therefore, if the phase of the plate cylinder 11 is manipulated in order to reduce the misregistration, a misregistration will occur in the subsequent stage. For example, when the phase of the plate cylinder 11B of the second printing unit 10B is operated when there is a misregistration between the first printing unit 10A and the second printing unit 10B, the tension of the web 2 before and after the plate cylinder 11B As a result, a misregistration occurs between the second printing unit 10B and the third printing unit 10C.

  Therefore, when there is a misregistration between any one of the printing units, the registering unit 57 not only between the printing units but also all the printing units cooperate to correct the misregistration. To control. For example, when there is a misregistration between the first printing unit 10A and the second printing unit 10B, the registering unit 57 first calculates the misregistration amount between the first printing unit 10A and the second printing unit 10B. A control signal to be output to the drive motor 13B of the plate cylinder 11B is generated for reduction. Subsequently, the registering unit 57 calculates the amount of misregistration that will occur between the second printing unit 10B and the third printing unit 10C due to the tension variation caused by manipulating the phase of the plate cylinder 11B, and the misregistration. In order to reduce the amount, a control signal to be output to the drive motor 13C of the plate cylinder 11C is generated. Furthermore, the registering unit 57 calculates the amount of misregistration that will occur between the third printing unit 10C and the fourth printing unit 10D due to the tension variation caused by manipulating the phase of the plate cylinder 11C, and the amount of misregistration. Control signal to be output to the drive motor 13D of the plate cylinder 11D is generated. The matching unit 57 outputs the control signals thus generated to the drive motors 13 of the printing units 10.

  Subsequently, when the conveyance speed of the web 2 is accelerated or decelerated to change the printing speed, the tension of the web 2 between the plate cylinders varies due to the inertia moment of the free roll 20. In general, misregistration can occur when the tension varies. That is, the acceleration / deceleration of the conveyance speed of the web 2 causes a misregistration.

  On the other hand, when the determination unit 55 determines that the acceleration / deceleration is being performed, the matching unit 57 estimates (calculates) the tension fluctuation that will occur between the plate cylinders by the acceleration / deceleration based on the acceleration. Estimate (calculate) the misregistration that would be caused by tension fluctuations. Then, the matching unit 57 generates a control signal to be output to the drive motor 13 of the plate cylinder 11 so as to suppress the occurrence of the estimated misregistration. In other words, when the judgment unit 55 determines that the acceleration / deceleration is being performed by the determination unit 55, a registration deviation caused by the acceleration / deceleration actually occurs and the registration deviation amount calculation unit 52 calculates the registration deviation amount. Rather than controlling each plate cylinder 11 to reduce the amount of misregistration, a control signal to be output to the drive motor 13 is generated so as to suppress the occurrence of misregistration due to acceleration / deceleration. In other words, when the determination unit 55 determines that acceleration / deceleration is being performed, the matching unit 57 performs feed-forward control so that a registration error caused by acceleration / deceleration does not occur.

  Note that the matching unit 57 preferably estimates (calculates) the acceleration at the timing of outputting the control signal to each drive motor 13 based on the predicted value from the tendency prediction unit 56. The matching unit 57 estimates a tension fluctuation that will occur between the plate cylinders due to acceleration / deceleration based on the estimated acceleration.

  According to the multicolor printing system 100 according to the embodiment described above, it is determined whether or not the conveyance speed of the web 2 is accelerating / decelerating. The phase of each plate cylinder 11 of each printing unit 10 is adjusted. That is, the phase of each plate cylinder 11 of each printing unit 10 is adjusted in consideration of tension fluctuation caused by acceleration / deceleration of the web 2 conveyance speed. Thereby, when the conveyance speed of the web 2 is accelerated / decelerated, it is possible to shorten the time until the misregistration between all the plate cylinders converges. Further, the amount of misregistration during acceleration / deceleration is also reduced.

  Further, according to the multicolor printing system 100 according to the embodiment, when the conveyance speed of the web 2 is changed, based on the predicted value from the tendency prediction unit 56, the timing at which the control signal is output to the drive motor 13, That is, the acceleration at the timing for controlling the plate cylinder 11 is estimated. Then, based on the estimated acceleration, the tension fluctuation and the misregistration amount are estimated. In this case, since a more accurate misregistration amount can be estimated, the time until the misregistration between all plate cylinders converges when the conveyance speed of the web 2 is accelerated or decelerated can be further shortened.

  The multicolor printing system according to the embodiment has been described above. This embodiment is an exemplification, and it will be understood by those skilled in the art that various modifications can be made to combinations of the respective constituent elements and processing processes, and such modifications are also within the scope of the present invention. is there. A modification is shown below.

(Modification 1)
In the embodiment, the case where the multicolor printing system 100 includes the four printing units of the first printing unit 10A, the second printing unit 10B, the third printing unit 10C, and the fourth printing unit 10D is described, but the present invention is not limited to this. It is only necessary to have two or more printing units.

(Modification 2)
The calculation method of the misregistration amount is not limited to the calculation method of the embodiment. It will be understood by those skilled in the art that the misregistration amount can be calculated by another calculation method. For example, the amount of misregistration may be calculated using a photographed image obtained by photographing the registration mark.

  Any combination of the above-described embodiments and modifications is also useful as an embodiment of the present invention. The new embodiment generated by the combination has the effects of the combined embodiment and the modified examples.

  2 Web, 10 printing unit, 10A 1st printing unit, 10B 2nd printing unit, 10C 3rd printing unit, 10D 4th printing unit, 11 plate cylinder, 13 drive motor, 22 free roll, 50 control device, 51 register mark A detection unit, a 52 misregistration amount calculation unit, a 54 acceleration calculation unit, a 55 determination unit, a 56 trend prediction unit, a 57 matching unit, and a 100 multicolor printing system.

Claims (3)

A multi-color printing system for printing on a web with a plurality of plate cylinders,
A determination unit for determining whether or not the web conveyance speed has changed;
A multi-color printing, comprising: a matching unit that controls the plurality of plate cylinders so that a print pattern printed on the web by the plurality of plate cylinders does not shift according to a determination result by the determination unit system. A trend prediction unit for predicting a change in web conveyance speed,
The matching unit controls the plurality of plate cylinders so that a printing pattern printed on the web by the plurality of plate cylinders does not shift according to the determination result by the determination unit and the prediction by the tendency prediction unit. The multicolor printing system according to claim 1. A method implemented in a multicolor printing system for printing on a web with a plurality of plate cylinders, comprising:
Determining whether the web transport speed has changed,
And a step of controlling the plurality of plate cylinders so that a printing pattern printed on the web by the plurality of plate cylinders does not shift according to the determination result.

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