Process and system for register control of a flexographic intaglio combination press
By receiving switch signals and using filtering technology, the position difference of the printing roller is calculated. Combined with the adjustment amount of the previous gravure printing color group, the motor speed is adjusted, which solves the problem of color registration control of the rear gravure printing color group of the flexographic gravure printing combination machine and achieves high-precision, low-cost and real-time color registration effect.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SIEMENS FACTORY AUTOMATION ENG
- Filing Date
- 2023-06-09
- Publication Date
- 2026-08-04
AI Technical Summary
In the existing technology, it is difficult to simultaneously achieve low cost, high precision, and good real-time performance in the color matching control of the rear gravure printing color group in the flexographic and gravure combined printing machine.
A color registration control method and system is adopted, which receives a switch signal, measures the current position of the motor shaft, calculates the position difference of the printing roller, performs limiting and filtering, and adjusts the motor speed in combination with the position adjustment amount of the previous gravure color group to achieve accurate color registration.
It achieves high-precision color registration control of the gravure printing color group at the rear of the flexographic and gravure printing combination machine, reducing equipment costs and improving real-time performance and user experience.
Smart Images
Figure CN116587731B_ABST
Abstract
Description
Technical Field
[0001] This application relates to color registration for flexographic and gravure combination machines, and more specifically, to an improved method and system for color registration control of gravure color groups located after flexographic color groups in a combination flexographic and gravure printing machine. Background Technology
[0002] Gravure printing and flexographic printing (such as flexographic printing press) are two commonly used printing technologies. Flexographic printing press has advantages over gravure printing in terms of printing dots, post-press process combinations, and environmental protection; while gravure printing has advantages over flexographic printing press in terms of printing seams and color (see Table 1). With increasingly stringent environmental protection requirements and print quality standards in various regions, the demand for a new combination of flexographic and gravure printing presses is constantly growing in order to fully leverage the advantages of both processes.
[0003] Table 1 Comparison of flexographic and gravure printing in the unit
[0004]
[0005] Currently, the common combination of flexographic and gravure printing presses involves adding one to three gravure color units to the rear of a standard flexographic press. Each gravure color unit is used for gravure printing of one color. With one gravure color unit, the combined flexographic and gravure printing press includes: an unwinding unit for feeding the printing roll; a feed traction unit for pulling the printing roll towards the flexographic color unit while maintaining tension; the flexographic color unit for flexographic printing; an intermediate traction unit for unwinding the flexographically printed roll and feeding it into the subsequent gravure printing unit; a feed traction unit for pulling the flexographically printed roll towards the gravure color unit while maintaining tension; the gravure color unit for gravure printing; an unwind traction unit for unwinding the gravureally printed roll while maintaining tension; and a rewinding unit for rewinding the roll, completing the printing process. In this combined equipment, both the flexographic printing unit and the subsequent gravure printing unit require color registration during printing, typically with an accuracy requirement of ±0.15mm and a speed of 130m / min. Therefore, a color registration control scheme for the subsequent gravure printing unit in a combined flexographic and gravure printing machine is necessary.
[0006] Currently, there are two control schemes for color registration control of gravure printing units located after the flexographic printing units in flexographic-gravure combination presses. The first scheme involves integrating the combination press with a third-party color registration system. This system measures and calculates the printing position error and uses its algorithm to calculate the registration amount. The combination press's control system then executes the color registration. However, this scheme requires a separate third-party color registration system, which is costly. Furthermore, the extensive signal interaction between the combination press's control system and the third-party system leads to a higher failure rate and more after-sales maintenance issues. The second scheme uses a third-party color mark sensor to measure the printing position error, which is transmitted to the combination press's control system via a PN bus. The control system then calculates the registration amount based on an integrated color registration algorithm and controls the motor to complete the color registration. However, this scheme requires a dedicated BST color mark analog sensor, which is expensive. Summary of the Invention
[0007] This application is made in view of the above-mentioned problems. The main purpose of this application is to provide a color registration control method and system for a flexographic and gravure combination machine, so as to solve the technical problem in the prior art that it is difficult to achieve low cost, high precision and good real-time performance in the color registration control of the rear gravure color group in a flexographic and gravure combination machine.
[0008] To achieve the above objectives, according to one aspect of this application, a color registration control method for a flexographic-gravure combination machine is provided. The flexographic-gravure combination machine includes a flexographic color group and multiple gravure color groups connected in series after the flexographic color group. The multiple gravure color groups include a current gravure color group, which is equipped with a motor for driving a printing roller to perform gravure printing on printing material. The color registration control method comprises: receiving a switch signal, wherein the switch signal is a signal output by a color mark sensor located at a predetermined position above the printing material at the output end of the current gravure color group when it detects a preset color mark on the printing material; the motor shaft of the motor is preset with a reference position corresponding to the position of the current color mark sensor and the position of the color mark on the printing material; measuring the timing of the rising edge of the switch signal to obtain the current position of the motor shaft corresponding to the timing; and calculating the... The motor position difference between the current position of the machine shaft and the reference position is calculated; the motor position difference is converted into a corresponding printing roller position difference; the printing roller position difference is limited to obtain a limited printing roller position difference; the limited printing roller position difference is filtered to obtain a filtered printing roller position difference after removing interference signals; the filtered printing roller position difference is converted into the initial position adjustment amount of the current gravure color group; the final position adjustment amount of the previous gravure color group before the current gravure color group is obtained, and the final position adjustment amount of the current gravure color group is determined based on the initial position adjustment amount of the current gravure color group and the final position adjustment amount of the previous gravure color group; wherein, the final position adjustment amount of the first gravure color group immediately following the flexographic color group is the initial position adjustment amount of the first gravure color group; the motor speed is adjusted according to the final position adjustment amount of the current gravure color group.
[0009] Furthermore, according to one embodiment of this application, the color mark is a color mark from the flexographic color group set for the first color of flexographic printing.
[0010] Further, according to one embodiment of this application, measuring the timing of the rising edge of the switch signal to obtain the current position of the motor shaft corresponding to the timing includes: after measuring the timing of the rising edge of the switch signal, obtaining the rotational position of the motor shaft corresponding to the measured timing of the rising edge from an encoder disposed on the motor shaft, as the current position of the motor shaft.
[0011] Furthermore, according to one embodiment of this application, the motor position difference and the printing roller position difference are in a first predetermined ratio, the first predetermined ratio being related to the radius of the printing roller.
[0012] Furthermore, according to one embodiment of this application, limiting the printing roller position difference includes setting an upper limit on the printing roller position difference, which includes: comparing the printing roller position difference with a preset upper limit threshold; when the printing roller position difference is greater than or equal to the upper limit threshold, adjusting the printing roller position difference to a limited printing roller position difference that is less than the upper limit threshold.
[0013] Further, according to one embodiment of this application, filtering the position difference of the printing roller after the limiting includes: calculating the difference between the position difference of the printing roller after the limiting and the previous position difference of the printing roller after the limiting corresponding to a previous switch signal before the switch signal; when the difference is within a preset filtering threshold range, the position difference of the printing roller after the limiting is used as the filtered position difference of the printing roller; when the difference is outside the preset filtering threshold range, the filtered position difference of the printing roller is set to 0.
[0014] Further, according to one embodiment of this application, the filtered plate roller position difference includes length and direction, the initial position adjustment amount includes the adjustment time and speed adjustment direction of the plate roller of the current gravure color group, the speed adjustment direction includes acceleration and deceleration, the plate roller has a preset fixed speed change amount, and converting the filtered plate roller position difference into the initial position adjustment amount of the current gravure color group includes: determining the adjustment time of the plate roller based on the length of the filtered plate roller position difference, the radius of the plate roller and the speed change amount, and determining the speed adjustment direction of the plate roller based on the direction of the filtered plate roller position difference.
[0015] Further, according to one embodiment of this application, determining the final position adjustment amount of the current gravure color group based on the initial position adjustment amount of the current gravure color group and the final position adjustment amount of the previous gravure color group includes: calculating the sum of the initial position adjustment amount of the current gravure color group and the final position adjustment amount of the previous gravure color group as the final position adjustment amount of the current gravure color group.
[0016] According to another aspect of this application, a color registration control system for a flexographic-gravure combination machine is also provided. The flexographic-gravure combination machine includes a flexographic color group and multiple gravure color groups connected in series after the flexographic color group. The multiple gravure color groups include a current gravure color group, which is equipped with a motor for driving a printing roller to perform gravure printing on printing material. The color registration control system comprises: multiple color mark sensors, each color mark sensor located at a predetermined position above the printing material at the output end of a corresponding gravure color group and configured to output a switch signal when a preset color mark is detected on the printing material; the multiple color mark sensors include a current color mark sensor corresponding to the current gravure color group; the motor shaft of the motor for the current gravure color group is preset with a reference position corresponding to the position of the current color mark sensor and the position of the color mark on the printing material; and a control device, comprising: an input measurement unit connected to the current color mark sensor and configured to: receive a switch signal from the current color mark sensor, measure the timing of the rising edge of the switch signal to obtain the electrical signal corresponding to the timing. The system includes: a current position of the motor shaft; an error calculation unit configured to calculate the motor position difference between the current position of the motor shaft and the reference position, and convert the motor position difference into a corresponding printing roller position difference; an error limiting unit configured to limit the printing roller position difference to obtain a limited printing roller position difference; an error filtering unit configured to filter the limited printing roller position difference to obtain a filtered printing roller position difference after removing interference signals; and an adjustment amount calculation unit configured to convert the filtered printing roller position difference into the initial position adjustment of the current gravure printing color group. A coupling unit is configured to: acquire the final position adjustment amount of the previous gravure color group preceding the current gravure color group, and determine the final position adjustment amount of the current gravure color group based on the initial position adjustment amount of the current gravure color group and the final position adjustment amount of the previous gravure color group; wherein the final position adjustment amount of the first gravure color group immediately following the flexographic color group is the initial position adjustment amount of the first gravure color group; and a motor drive unit is configured to adjust the speed of the motor according to the final position adjustment amount of the current gravure color group.
[0017] Furthermore, according to one embodiment of this application, the color mark is a color mark from the flexographic color group set for the first color of flexographic printing.
[0018] Furthermore, according to one embodiment of this application, the input measurement unit is further configured to: after measuring the timing of the rising edge of the switch signal, obtain from the encoder disposed on the motor shaft the rotational position of the motor shaft corresponding to the timing of the measured rising edge, as the current position of the motor shaft.
[0019] Furthermore, according to one embodiment of this application, the motor position difference and the printing roller position difference are in a first predetermined ratio, the first predetermined ratio being related to the radius of the printing roller.
[0020] Furthermore, according to one embodiment of this application, the error limiting unit is pre-set with an upper limit threshold, and the error limiting unit is further configured to: compare the plate roller position difference with the upper limit threshold; when the plate roller position difference is greater than or equal to the upper limit threshold, adjust the plate roller position difference to a limited plate roller position difference that is less than the upper limit threshold.
[0021] Furthermore, according to one embodiment of this application, the error filtering unit is pre-set with a filtering threshold range, and the error filtering unit is further configured to: calculate the difference between the narrowed roller position difference and the previous narrowed roller position difference corresponding to the previous switch signal before the switch signal; when the difference is within the preset filtering threshold range, the narrowed roller position difference is used as the filtered roller position difference; when the difference is outside the preset filtering threshold range, the filtered roller position difference is set to 0.
[0022] Furthermore, according to one embodiment of this application, the filtered plate roller position difference includes length and direction, the initial position adjustment amount includes the adjustment time and speed adjustment direction of the plate roller of the current gravure color group, the speed adjustment direction includes acceleration and deceleration, the plate roller has a preset fixed speed change amount, and the adjustment amount calculation unit is further configured to: determine the adjustment time of the plate roller based on the length of the filtered plate roller position difference, the radius of the plate roller and the speed change amount, and determine the speed adjustment direction of the plate roller based on the direction of the filtered plate roller position difference.
[0023] Furthermore, according to one embodiment of this application, the coupling unit is further configured to: calculate the sum of the initial position adjustment amount of the current gravure color group and the final position adjustment amount of the previous gravure color group as the final position adjustment amount of the current gravure color group.
[0024] In this application embodiment, a color registration control method and system for a flexographic-gravure printing combination machine is provided. The flexographic-gravure printing combination machine includes a flexographic color group and multiple gravure color groups connected in series after the flexographic color group. The multiple gravure color groups include a current gravure color group. The current gravure color group is equipped with a motor for driving the printing roller to perform gravure printing on the printing material. The color registration control method includes: receiving a switch signal, the switch signal being a signal output by a color mark sensor located at a predetermined position above the printing material at the output end of the current gravure color group when it detects a preset color mark on the printing material; the motor shaft of the motor having a preset reference position corresponding to the position of the current color mark sensor and the position of the color mark on the printing material; measuring the timing of the rising edge of the switch signal to obtain the current position of the motor shaft corresponding to the timing; calculating the motor position difference between the current position of the motor shaft and the reference position; converting the motor position difference into a corresponding printing roller position difference; and limiting the printing roller position difference to obtain... The position difference of the printing roller after the width limit is calculated; the position difference of the printing roller after the width limit is filtered to obtain a filtered position difference of the printing roller after removing interference signals; the filtered position difference of the printing roller is converted into the initial position adjustment amount of the current gravure color group; the final position adjustment amount of the previous gravure color group before the current gravure color group is obtained, and the final position adjustment amount of the current gravure color group is determined based on the initial position adjustment amount of the current gravure color group and the final position adjustment amount of the previous gravure color group; wherein, the final position adjustment amount of the first gravure color group immediately following the flexographic color group is the initial position adjustment amount of the first gravure color group; the speed of the motor is adjusted according to the final position adjustment amount of the current gravure color group, so as to at least solve the technical problem in the prior art that it is difficult to achieve low cost, high precision and good real-time performance in the color registration control of the rear gravure color group in the flexographic gravure combination machine, thereby achieving the technical effect of high precision, good real-time performance and low cost in the color registration control of the rear gravure color group in the flexographic gravure combination machine. Attached Figure Description
[0025] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings:
[0026] Figure 1 A schematic diagram of a flexographic-gravure combination machine to which the color matching control method and system for flexographic-gravure combination machine according to this application can be applied is shown.
[0027] Figure 2 A flowchart of a color matching control method for a flexographic and gravure printing press according to an embodiment of this application is shown;
[0028] Figure 3 A schematic block diagram of a color matching control system for a flexographic and gravure printing press according to an embodiment of this application is shown; and
[0029] Figure 4 A schematic diagram showing the connection between the color matching control system for a flexographic-gravure combination machine and the current gravure color group of the flexographic-gravure combination machine according to an embodiment of this application is shown.
[0030] The above figures include the following reference numerals:
[0031] 100: Flexographic and Gravure Printing Combined Machine
[0032] 110: Soft Print Color Set
[0033] 120: Gravure printing color set
[0034] 121: Electric motor
[0035] 200: Color registration control method for flexographic and gravure combined printing presses
[0036] 300: Color matching control system for flexographic and gravure printing combination machines
[0037] 310: Color mark sensor
[0038] 320: Control device
[0039] 321: Input Measurement Unit
[0040] 322: Error Calculation Unit
[0041] 323: Error Limiting Unit
[0042] 324: Error Filtering Unit
[0043] 325: Adjustment Calculation Unit
[0044] 326: Coupling Unit
[0045] 327: Motor drive unit
[0046] 400: Printing materials
[0047] 410: Color swatches Detailed Implementation
[0048] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.
[0049] It should be noted that, unless otherwise specified, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.
[0050] In this application, unless otherwise stated, directional terms such as "upper," "lower," "top," and "bottom" are generally used in relation to the direction shown in the accompanying drawings, or in relation to the vertical, perpendicular, or gravitational direction of the component itself; similarly, for ease of understanding and description, "inner" and "outer" refer to the inner and outer contours of each component itself, but the above directional terms are not intended to limit this application.
[0051] The purpose of this application is to provide an improved method and system for color registration control in the rear gravure printing of a flexographic-gravure combination machine, which can reduce equipment costs and improve user experience while meeting printing speed and color registration accuracy requirements.
[0052] In this application, the flexographic-gravure combination machine includes a flexographic ink unit and multiple gravure ink units connected in series after the flexographic ink unit. Each gravure ink unit includes a printing roller and is equipped with a motor for driving the printing roller to perform gravure printing on the printing material. For example, the flexographic-gravure combination machine can be a unit flexographic-gravure combination machine composed of a unit flexographic ink unit and multiple gravure ink units located after it.
[0053] Figure 1 A schematic diagram is shown of a flexographic-gravure combination machine 100 to which the color matching control method and system for flexographic-gravure combination machines according to this application can be applied. Figure 1 As shown, the flexographic and gravure printing combination machine 100 includes a flexographic ink group 110 and a plurality of gravure ink groups 120 connected in series after the flexographic ink group 110 along the direction of travel of the printing material 400. The number of gravure ink groups 120 is two or more, typically three. Each of the flexographic ink group 110 and the gravure ink group 120 includes a corresponding printing roller (not shown) for printing. The flexographic ink group 110 is driven by two motors (not shown), one for feeding the printing material and the other for driving the printing roller for printing. Each gravure ink group 120 is driven by one motor (not shown), which is used for both feeding the printing material and driving the printing roller for printing.
[0054] The color registration control method and system for a flexographic-gravure combination machine according to this application can be applied to any gravure color group 120 in the flexographic-gravure combination machine 100. Hereinafter, the color registration control method and system for the flexographic-gravure combination machine are described with respect to the current gravure color group 120 (which can be any gravure color group) among the plurality of gravure color groups 120 of the flexographic-gravure combination machine 100.
[0055] Figure 2 A flowchart of a color matching control method for a flexographic and gravure printing press according to an embodiment of this application is shown. Figure 3 A schematic block diagram of a color matching control system for a flexographic and gravure printing press according to an embodiment of this application is shown. Figure 4 A schematic diagram showing the connection between the color registration control system for a flexographic-gravure combination machine and the current gravure color group of the flexographic-gravure combination machine according to an embodiment of this application is shown. Next, referring to... Figures 2 to 4 The technical solution of this application is described in detail.
[0056] The color registration control method 200 for a flexographic gravure printing press according to this application includes: S210, receiving a switch signal, the switch signal being a signal output by a color mark sensor located at a predetermined position above the printing material at the output end of the current gravure color group when it detects a preset color mark on the printing material, wherein the motor shaft of the motor for the current gravure color group is preset with a reference position corresponding to the position of the current color mark sensor and the position of the color mark on the printing material; S220, measuring the timing of the rising edge of the switch signal to obtain the current position of the motor shaft corresponding to the timing; S230, calculating the motor position difference between the current position of the motor shaft and the reference position; S240, converting the motor position difference into a corresponding plate roller position difference; S250, limiting the plate roller position difference. S260: The position difference of the printing roller after the width limit is obtained; S270: The position difference of the printing roller after the width limit is filtered to obtain the filtered position difference of the printing roller after removing interference signals; S280: The filtered position difference of the printing roller is converted into the initial position adjustment amount of the current gravure color group; S290: The final position adjustment amount of the previous gravure color group before the current gravure color group is obtained, and the final position adjustment amount of the current gravure color group is determined based on the initial position adjustment amount of the current gravure color group and the final position adjustment amount of the previous gravure color group, wherein the final position adjustment amount of the first gravure color group immediately following the flexographic color group is the initial position adjustment amount of the first gravure color group; S2011: The speed of the motor is adjusted according to the final position adjustment amount of the current gravure color group.
[0057] The color matching control system 300 for a flexographic gravure printing press according to this application includes: a plurality of color mark sensors 310, each color mark sensor 310 being located at a predetermined position above the printing material 400 at the output end of a corresponding gravure color group 120 and configured to output a switch signal when a preset color mark 410 is detected on the printing material 400; the plurality of color mark sensors 310 includes a current color mark sensor 310 corresponding to the current gravure color group 120; a motor shaft (not shown) of a motor 121 for the current gravure color group 120 is preset with a reference position corresponding to the position of the current color mark sensor 310 and the position of the color mark 410 on the printing material; and a control device 320, including: an input measurement unit 321 connected to the current color mark sensor 310 and configured to: receive a switch signal from the current color mark sensor 310 and measure the timing of the rising edge of the switch signal to obtain the current position of the motor shaft corresponding to the timing; and an error calculation unit 322 configured to calculate the electrical error between the current position of the motor shaft and the reference position. The machine position difference is calculated and converted into the corresponding printing roller position difference; the error limiting unit 323 is configured to limit the printing roller position difference to obtain the limited printing roller position difference; the error filtering unit 324 is configured to filter the limited printing roller position difference to obtain the filtered printing roller position difference after removing interference signals; the adjustment amount calculation unit 325 is configured to convert the filtered printing roller position difference into the initial position adjustment amount of the current gravure color group; the coupling unit 326 is configured to: obtain the final position adjustment amount of the previous gravure color group before the current gravure color group 120 in multiple gravure color groups, and determine the final position adjustment amount of the current gravure color group based on the initial position adjustment amount of the current gravure color group 120 and the final position adjustment amount of the previous gravure color group; wherein, the final position adjustment amount of the first gravure color group immediately following the flexographic color group 110 is the initial position adjustment amount of the first gravure color group; the motor drive unit 327 is configured to adjust the motor speed according to the final position adjustment amount of the current gravure color group 120.
[0058] In this application, the aforementioned color registration control is performed in real time during gravure printing. Specifically, the color registration control method 200 for a flexographic-gravure combination machine 100 according to this application can be executed by a control device 320. The control device 320 can be implemented as a programmable logic controller (PLC) for the flexographic-gravure combination machine 100. Because color registration control is implemented using the control system of the flexographic-gravure combination machine itself, rather than external control hardware, good real-time performance can be achieved and extensive communication with external devices is avoided.
[0059] In this application, the switch signal is a digital signal represented by 0 and 1. Color mark 410 is a color mark set for the first color of flexographic printing from the flexographic color group 110. For example... Figure 4As shown, color stops 410 are set on the printing material 400, and can be set at predetermined intervals. For example, the color stop 410 can be a rectangular pattern along the edge of the printing material 400. In this way, there is no need to reset the color stops for the gravure color group 120, but the same color stops from the flexographic color group 110 can be used. That is, the operation of setting the color stops 410 in the gravure color group 120 can be omitted, thereby improving the user experience.
[0060] Furthermore, in this application, the multiple color mark sensors 310 are of the same type as the color mark sensors used for color matching control of the flexographic color group 110. These color mark sensors are, for example, single-color mark tri-color sensors that output switching signals, capable of outputting switching signals for any color when a grayscale difference greater than a threshold is detected. In practical applications, for example, a P+F color mark sensor can be used.
[0061] In this way, the same low-cost color mark sensor as the flexographic color set can be used in this application, without the need to set up an additional color mark sensor dedicated to the gravure color set, thereby greatly reducing equipment costs.
[0062] In this application, firstly, the current color mark sensor 310 at the output terminal of the current gravure color group 120 outputs a switch signal in response to detecting a color mark 410. In S210, the input measurement unit 321 receives the switch signal from the current color mark sensor 310. Then, in S220, the input measurement unit 321 measures the timing of the rising edge of the switch signal to obtain the current position of the motor shaft corresponding to that timing. Specifically, after measuring the timing of the rising edge of the switch signal, the input measurement unit 321 can obtain the rotational position of the motor shaft corresponding to the measured timing of the rising edge from an encoder mounted on the motor shaft, as the current position of the motor shaft. The rotational position of the motor shaft can be represented by an angle. The reference position of the motor shaft can also be represented by an angle.
[0063] The input measurement unit 321 can output the measured current position of the motor shaft to the error calculation unit 322. Next, in S230, the error calculation unit 322 calculates the motor position difference between the current position of the motor shaft and the reference position. The motor position difference can be the difference obtained by subtracting the reference position (e.g., 120°) from the current position of the motor shaft (e.g., 120.2°).
[0064] Then, in S240, the error calculation unit 322 further converts the calculated motor position difference into the corresponding printing roller position difference. Since the printing roller is driven by a motor, the motor position difference and the printing roller position difference are in a first predetermined ratio, which is related to the radius of the printing roller. Furthermore, this first predetermined ratio is related to the radius of the printing roller and the reduction ratio of the gearbox (not shown) connecting the motor 121 and the printing roller. In this application, the position of the printing roller and the corresponding printing roller position difference can be represented by an angle or an arc length.
[0065] Error calculation unit 322 can output the obtained roller position difference to error limiting unit 323. In S250, error limiting unit 323 limits the roller position difference to obtain a limited roller position difference. Limiting includes a lower limit and an upper limit. Lower limiting includes: comparing the roller position difference with a preset lower limit threshold; when the roller position difference is greater than or equal to the lower limit threshold, outputting the roller position difference; when the roller position difference is less than the lower limit threshold, ignoring the roller position difference. Lower limiting can eliminate interference from noise signals. For example, the lower limit threshold can be the arc length of the outer circumference of the roller corresponding to a 0.05° central angle. Upper limiting includes: comparing the roller position difference with a preset upper limit threshold; when the roller position difference is greater than or equal to the upper limit threshold, adjusting the roller position difference to a limited roller position difference that is less than the upper limit threshold, and this limited roller position difference is greater than the lower limit threshold. When the position difference of the printing rollers is less than the upper limit threshold, this position difference is output as the limited position difference of the printing rollers. Furthermore, the position difference of the printing rollers can be positive or negative. When the absolute value of the position difference of the printing rollers is greater than or equal to the preset upper limit threshold, the position difference of the printing rollers is adjusted to a limited position difference whose absolute value is less than the upper limit threshold. When the absolute value of the position difference of the printing rollers is less than the preset upper limit threshold, this position difference is output as the limited position difference of the printing rollers.
[0066] By setting an upper limit, printing errors can be avoided by directly adjusting the motor speed drastically based on an excessively large difference in the calculated position of the printing rollers. This would prevent the printing material from maintaining tension (e.g., causing the printing material to loosen). For example, the upper limit threshold could be the arc length of the outer circumference of the printing roller corresponding to a central angle of 0.1°, 0.2°, or 0.3°.
[0067] Error limiting unit 323 can output the obtained limited roller position difference to error filtering unit 324. Next, in S260, error filtering unit 324 filters the limited roller position difference to remove interference from erroneous signals output from the color mark sensor that do not originate from the color mark. Erroneous signals are interference signals output from the color mark sensor during the detection of color marks using a switch-type color mark sensor, caused by factors such as different printed inks, ink smudges, or ink vibration. The filtering includes: acquiring the previous limited roller position difference corresponding to the previous switch signal before the aforementioned switch signal; calculating the difference between the current limited roller position difference corresponding to the aforementioned switch signal and the previous limited roller position difference; when the difference is within a preset filtering threshold range, the current limited roller position difference is used as the filtered roller position difference; when the difference is outside the preset filtering threshold range, the filtered roller position difference is set to 0, i.e., the current detection is ignored, and the motor speed is not adjusted.
[0068] For example, the position difference of the printing roller after the previous limiting can be the position difference of the printing roller after the previous one or more limiting corresponding to the previous one or more switching signals. For example, the preset filtering threshold range can be the arc length of the outer circumference of the printing roller corresponding to a central angle of -0.5° to +0.5°.
[0069] In this way, since the roller position difference calculated from the error signal will deviate significantly from the roller position difference calculated from the color mark signal, the interference of the error signal can be removed by filtering.
[0070] The error filtering unit 324 can output the filtered plate roller position difference to the adjustment amount calculation unit 325. In S270, the adjustment amount calculation unit 325 converts the filtered plate roller position difference into the initial position adjustment amount of the current gravure color group 120.
[0071] In this application, the filtered plate roller position difference includes length and direction. The direction includes a positive direction and a negative direction. The initial position adjustment amount includes the adjustment time and speed adjustment direction of the plate roller of the current gravure color group 120. The speed adjustment direction includes acceleration and deceleration. The plate roller has a preset fixed speed change amount. That is, the plate roller and the corresponding motor are superimposed on the initial speed with a fixed speed change amount each time, but the adjustment time and speed adjustment direction change with the plate roller position difference. The adjustment amount calculation unit 325 is further configured to: determine the adjustment time of the plate roller based on the length of the filtered plate roller position difference, the radius of the plate roller, and the speed change amount, and determine the speed adjustment direction of the plate roller based on the direction of the filtered plate roller position difference. Specifically, the fixed speed change amount can be a fixed angular velocity change amount, thereby using this length as the arc length, and the adjustment time can be calculated based on the radius of the plate roller and the angular velocity change amount. Furthermore, the positive direction of the plate roller position difference corresponds to deceleration, and the negative direction corresponds to acceleration. Specifically, when the filtered position difference of the printing roller is positive, it indicates that the current position of the printing roller is larger than its reference position. Similarly, the current position of the motor shaft is also larger than its reference position. Therefore, the printing roller needs to decelerate, meaning the current speed of the motor needs to decrease. Conversely, when the filtered position difference of the printing roller is negative, it indicates that the current position of the printing roller is smaller than its reference position. Therefore, the printing roller needs to accelerate, meaning the current speed of the motor needs to increase.
[0072] Then, the adjustment calculation unit 325 can output the calculated initial position adjustment amount of the current gravure color group 120 to the coupling unit 326. In S280, the coupling unit 326 acquires the final position adjustment amount of the previous gravure color group preceding the current gravure color group 120 among multiple gravure color groups, and determines the final position adjustment amount of the current gravure color group 120 based on the initial position adjustment amount of the current gravure color group 120 and the final position adjustment amount of the previous gravure color group. The final position adjustment amount of the first gravure color group immediately following the flexographic color group 110 is the initial position adjustment amount of the first gravure color group itself. The coupling unit 326 is further configured to calculate the sum of the initial position adjustment amount of the current gravure color group 120 and the final position adjustment amount of the previous gravure color group as the final position adjustment amount of the current gravure color group 120.
[0073] In other words, when the current gravure printing color group 120 is the first gravure printing color group immediately following the flexographic printing color group 110, the initial position adjustment amount calculated by the adjustment amount calculation unit 325 is the final position adjustment amount of the first gravure printing color group, which is output to the motor drive unit 327 by the coupling unit 326. When the current gravure printing color group 120 is the second gravure printing color group after the flexographic printing color group 110, the final position adjustment amount of the second gravure printing color group is the sum of the initial position adjustment amount calculated for it and the final position adjustment amount of the first gravure printing color group (i.e., the vector sum considering the direction), and so on. The final position adjustment amount also includes the corresponding printing roller adjustment time and speed adjustment direction.
[0074] Then, the coupling unit 326 outputs the final position adjustment amount of the current gravure color group 120 to the motor drive unit 327. In S290, the motor drive unit 327 adjusts the rotational speed of the motor 121 for the current gravure color group 120 according to the final position adjustment amount. Specifically, the motor drive unit 327, based on a preset fixed angular velocity change of the motor 121 (which is proportional to a preset fixed angular velocity change of the printing roller), superimposes (i.e., increases or decreases) the reference rotational speed of the motor according to the adjustment time and speed adjustment direction indicated by the final position adjustment amount, thereby obtaining the adjusted motor rotational speed and the adjustment time for operating at the adjusted rotational speed. By driving the motor at the adjusted motor rotational speed according to the adjustment time, one adjustment of the color registration of the current gravure color group 120 can be completed. During the gravure printing process, since the color marks 410 are set on the printing material 400 at predetermined intervals, the motor rotational speed can be continuously adjusted according to the switching signal output by the current color mark sensor 310.
[0075] In this application, the color mark sensor 310 and the control device 320 can be connected via a fast I / O bus to transmit switching signals (digital signals) in real time. The combination of the switch-type color mark sensor 310, the fast I / O bus, and the control device 320 (e.g., a PLC controller) can achieve excellent real-time transmission and processing, thereby achieving excellent real-time color matching control.
[0076] The color matching control method and system according to this application have the following advantages:
[0077] (1) Only a low-cost switch-type color mark sensor is used when detecting color marks, and the color mark sensor is the same model as the color mark sensor used in the flexographic printing machine of the unit, thus greatly reducing hardware costs.
[0078] (2) The switch-type color mark sensor is the same model as the color mark sensor used in the flexographic printing press. Therefore, the color mark used in the flexographic printing press can be used, which simplifies the operation of color mark setting of the combination machine and improves the customer experience.
[0079] (3) The color registration accuracy of the gravure printing part of the flexographic and gravure printing combination machine can reach ±0.15mm, and the printing speed of the equipment can reach 130m / min, which can meet the speed and accuracy requirements of printing.
[0080] (4) All color matching control processes involved are completed by the control system of the flexographic and gravure printing combination machine. There is no need to process at the color mark sensor or set up additional hardware for error calculation. Therefore, the equipment has higher integration, better real-time performance, and is easier to maintain and modify.
[0081] The flexographic and gravure combination machine according to this application can be used to print labels, such as labels on the outside of beer bottles or labels on the outer packaging of ballpoint pens.
[0082] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.
[0083] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Nouns and pronouns relating to persons in this patent application are not limited to specific genders.
[0084] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.
Claims
1. A color registration control method for a flexographic and gravure printing combination machine, the flexographic and gravure printing combination machine comprising a flexographic color group and a plurality of gravure color groups connected in series after the flexographic color group, the plurality of gravure color groups including a current gravure color group, the current gravure color group being provided with a motor for driving the printing roller to perform gravure printing on the printing material, characterized in that, The color matching control method includes: The switch signal is received by a color mark sensor located at a predetermined position above the printing material at the output end of the current gravure color group when it detects a preset color mark on the printing material. The motor shaft of the motor is preset with a reference position corresponding to the position of the current color mark sensor and the position of the color mark on the printing material. The timing of the rising edge of the switch signal is measured to obtain the current position of the motor shaft corresponding to the timing. Calculate the motor position difference between the current position of the motor shaft and the reference position; Convert the motor position difference into the corresponding printing roller position difference; The position difference of the printing rollers is limited to obtain a limited position difference of the printing rollers; The position difference of the printing rollers after the amplitude limiting is filtered to obtain the filtered position difference of the printing rollers after removing interference signals; The filtered difference in the position of the printing rollers is converted into the initial position adjustment amount of the current gravure color group; The final position adjustment amount of the previous gravure color group preceding the current gravure color group is obtained, and the final position adjustment amount of the current gravure color group is determined based on the initial position adjustment amount of the current gravure color group and the final position adjustment amount of the previous gravure color group; wherein, the final position adjustment amount of the first gravure color group immediately following the flexographic color group is the initial position adjustment amount of the first gravure color group. The speed of the motor is adjusted according to the final position adjustment amount of the current gravure color group.
2. The color registration control method for a flexographic and gravure printing combined machine according to claim 1, characterized in that, The color swatch is a color swatch set from the flexographic color group for the first color in flexographic printing.
3. The color registration control method for a flexographic and gravure printing combined machine according to claim 1 or 2, characterized in that, Measuring the timing of the rising edge of the switch signal to obtain the current position of the motor shaft corresponding to the timing includes: After measuring the timing of the rising edge of the switch signal, the rotational position of the motor shaft corresponding to the timing of the measured rising edge is obtained from the encoder mounted on the motor shaft, and is taken as the current position of the motor shaft.
4. The color registration control method for a flexographic and gravure printing combined machine according to claim 1 or 2, characterized in that, The position difference of the motor and the position difference of the printing roller are in a first predetermined ratio, and the first predetermined ratio is related to the radius of the printing roller.
5. The color registration control method for a flexographic and gravure printing combined machine according to claim 1 or 2, characterized in that, Limiting the position difference of the printing rollers includes setting an upper limit on the position difference of the printing rollers, which includes: The difference in the position of the printing rollers is compared with a preset upper limit threshold. When the difference in the position of the printing rollers is greater than or equal to the upper limit threshold, the difference in the position of the printing rollers is adjusted to a limited difference in the position of the printing rollers that is less than the upper limit threshold.
6. The color registration control method for a flexographic and gravure printing combined machine according to claim 1 or 2, characterized in that, Filtering the position difference of the printing rollers after the image is limited includes: Calculate the difference between the narrowed roller position difference and the previous narrowed roller position difference corresponding to the previous switch signal before the switch signal; When the difference is within the preset filtering threshold range, the difference in the position of the printing roller after the limit is taken as the difference in the position of the printing roller after the filter. When the difference is outside the preset filtering threshold range, the filtered roller position difference is set to 0.
7. The color registration control method for a flexographic and gravure printing combined machine according to claim 1 or 2, characterized in that, The filtered plate roller position difference includes length and direction. The initial position adjustment amount includes the adjustment time and speed adjustment direction of the plate roller of the current gravure color group. The speed adjustment direction includes acceleration and deceleration. The plate roller has a preset fixed speed change amount. Converting the filtered plate roller position difference into the initial position adjustment amount of the current gravure color group includes: The adjustment time of the printing roller is determined based on the length of the filtered roller position difference, the radius of the printing roller, and the speed change. The speed adjustment direction of the printing roller is determined based on the direction of the filtered roller position difference.
8. The color registration control method for a flexographic and gravure printing combined machine according to claim 1 or 2, characterized in that, Determining the final position adjustment amount of the current gravure color group based on the initial position adjustment amount of the current gravure color group and the final position adjustment amount of the previous gravure color group includes: The sum of the initial position adjustment amount of the current gravure color group and the final position adjustment amount of the previous gravure color group is calculated as the final position adjustment amount of the current gravure color group.
9. A color registration control system for a flexographic and gravure printing combination machine, the flexographic and gravure printing combination machine (100) comprising a flexographic color group (110) and a plurality of gravure color groups connected in series after the flexographic color group, the plurality of gravure color groups including a current gravure color group (120), the current gravure color group (120) being provided with a motor (121) for driving the printing roller to perform gravure printing on printing material (400), characterized in that, The color matching control system (300) includes: Multiple color mark sensors, each located at a predetermined position above the printing material at the output end of a corresponding gravure color group and configured to output a switch signal when a preset color mark (410) is detected on the printing material, the multiple color mark sensors including a current color mark sensor (310) corresponding to the current gravure color group (120), and a motor shaft of a motor (121) for the current gravure color group (120) having a preset reference position corresponding to the position of the current color mark sensor (310) and the position of the color mark (410) on the printing material (400); and Control device (320), including: An input measurement unit (321) is connected to the current color mark sensor and is configured to: receive a switch signal from the current color mark sensor and measure the timing of the rising edge of the switch signal to obtain the current position of the motor shaft corresponding to the timing. The error calculation unit (322) is configured to calculate the motor position difference between the current position of the motor shaft and the reference position, and convert the motor position difference into the corresponding roller position difference; The error limiting unit (323) is configured to limit the position difference of the printing rollers to obtain the limited position difference of the printing rollers; The error filtering unit (324) is configured to filter the roller position difference after the limiting to obtain the filtered roller position difference after removing the interference signal; The adjustment calculation unit (325) is configured to convert the filtered plate roller position difference into the initial position adjustment amount of the current gravure color group (120); The coupling unit (326) is configured to: obtain the final position adjustment amount of the previous gravure color group preceding the current gravure color group (120) among the plurality of gravure color groups, and determine the final position adjustment amount of the current gravure color group based on the initial position adjustment amount of the current gravure color group (120) and the final position adjustment amount of the previous gravure color group; wherein, the final position adjustment amount of the first gravure color group immediately following the flexographic color group (110) is the initial position adjustment amount of the first gravure color group; The motor drive unit (327) is configured to adjust the rotational speed of the motor (121) according to the final position adjustment amount of the current gravure color group (120).
10. The color registration control system for a flexographic and gravure printing combined machine according to claim 9, characterized in that, The color mark (410) is a color mark set for the first color of flexographic printing from the flexographic color group (110).
11. The color registration control system for a flexographic and gravure printing combined machine according to claim 9 or 10, characterized in that, The input measurement unit (321) is further configured as follows: After measuring the timing of the rising edge of the switch signal, the rotational position of the motor shaft corresponding to the timing of the measured rising edge is obtained from the encoder mounted on the motor shaft, and is taken as the current position of the motor shaft.
12. The color registration control system for a flexographic and gravure printing combined machine according to claim 9 or 10, characterized in that, The position difference of the motor and the position difference of the printing roller are in a first predetermined ratio, and the first predetermined ratio is related to the radius of the printing roller.
13. The color registration control system for a flexographic and gravure printing combined machine according to claim 9 or 10, characterized in that, The error limiting unit (323) is pre-set with an upper limit threshold, and the error limiting unit is further configured as follows: Compare the roller position difference with the upper limit threshold. When the difference in the position of the printing rollers is greater than or equal to the upper limit threshold, the difference in the position of the printing rollers is adjusted to a limited difference in the position of the printing rollers that is less than the upper limit threshold.
14. The color registration control system for a flexographic and gravure printing combined machine according to claim 9 or 10, characterized in that, The error filtering unit (324) has a preset filtering threshold range, and the error filtering unit is further configured as follows: Calculate the difference between the narrowed roller position difference and the previous narrowed roller position difference corresponding to the previous switch signal before the switch signal; When the difference is within the preset filtering threshold range, the difference in the position of the printing roller after the limit is taken as the difference in the position of the printing roller after the filter. When the difference is outside the preset filtering threshold range, the filtered roller position difference is set to 0.
15. The color registration control system for a flexographic and gravure printing combined machine according to claim 9 or 10, characterized in that, The filtered roller position difference includes length and direction. The initial position adjustment amount includes the adjustment time and speed adjustment direction of the roller of the current gravure color group (120). The speed adjustment direction includes acceleration and deceleration. The roller has a preset fixed speed change amount. The adjustment amount calculation unit (325) is further configured as follows: The adjustment time of the printing roller is determined based on the length of the filtered roller position difference, the radius of the printing roller, and the speed change. The speed adjustment direction of the printing roller is determined based on the direction of the filtered roller position difference.
16. The color registration control system for a flexographic and gravure printing combined machine according to claim 9 or 10, characterized in that, The coupling unit (326) is further configured as follows: The sum of the initial position adjustment amount of the current gravure color group (120) and the final position adjustment amount of the previous gravure color group is calculated as the final position adjustment amount of the current gravure color group (120).