Synchronous registration embossed decorative paper printing equipment and printing method

Abstract

The present invention belongs to the technical field of embossed printing, and discloses synchronous registration embossed decorative paper printing equipment and a printing method; collecting comprehensive printing parameters, training a machine learning model to predict future printing ink color values, comparing the predicted future printing ink color values ​​with the ink color threshold, and generating a switching control instruction; the present invention collects comprehensive printing data that affects printing quality, and combines the machine learning model to predict the future printing ink color values, so that the switching control instruction can be issued in time before the embossed printing component fails to avoid printing accidents. At the same time, when the main embossed printing component needs to be repaired, the auxiliary embossed printing component can be started at a preset time node to perform seamless docking printing on the printed part, thereby achieving the working effect of the main embossed printing component and the auxiliary embossed printing component coordinating with each other, and improving the printing quality of the printing equipment.

Description

Technical Field

[0001] The present invention relates to the technical field of embossing printing, and more particularly to synchronous registration embossing decorative paper printing equipment and a printing method. Background Art

[0002] Embossed printing is a type of printing technology. In the production and processing of embossed printing on decorative paper, synchronous plate-registered embossed printing technology is required for printing. Since each printing device is equipped with multiple printing stations and the printing mechanism of each station has a large number of parts, mechanical fatigue or failure is prone to occur when the printing mechanism runs for a long time, resulting in a decline in the printing quality of the printing mechanism, and thus reduced the printing quality of the decorative paper.

[0003] The Chinese invention patent application, publication number CN103407282A, discloses a wide-width wallpaper printing and embossing production equipment. Through structural innovations in the gravure printing unit, oven unit, and embossing unit, it fundamentally solves the defects of narrow-width wallpaper. When pasting, the wallpaper is pasted horizontally, which greatly improves the wallpaper's wall-mounting effect and eliminates the color difference problems caused by multiple seams, pattern edge problems, and warping problems of wallpaper seams. At the same time, it greatly improves production efficiency and reduces energy consumption.

[0004] The existing technology has the following deficiencies:

[0005] In order to monitor the printing quality of decorative paper, existing printing equipment usually adopts a real-time printing monitoring method of decorative paper. The printing quality of the decorative paper is judged by obtaining the printing data of the decorative paper in the current state. This method has a certain lag when monitoring the printing quality of decorative paper, and cannot detect the safety hazards in the printing mechanism in advance and accurately. When the printing equipment detects that the printing data of the decorative paper is abnormal, it means that a printing fault has occurred in the printing component. When the printing equipment fails and needs to be repaired, the printing equipment often needs to be shut down, resulting in the interruption of the printing process and reduced printing efficiency.

[0006] In view of this, the present invention proposes a synchronous registration embossed decorative paper printing device and a printing method to solve the above problems. Summary of the Invention

[0007] In order to overcome the above-mentioned defects of the prior art and to achieve the above-mentioned purpose, the present invention provides the following technical solution: a synchronous registration embossed decorative paper printing device, comprising a printing machine body, a reeling frame, a reeling frame and a control terminal:

[0008] Several printing mechanisms are arranged at intervals on the printing machine body;

[0009] The unwinding rack unwinds the workpiece to be printed and guides it into the printing mechanism at the starting end. The workpiece to be printed is continuously transported and printed in several printing mechanisms. The rewinding rack rewinds the workpiece to be printed and guides it out of the printing mechanism at the terminal end.

[0010] The printing mechanism includes a printing frame, on which a main embossing printing component and a secondary embossing printing component are arranged in an upper and lower distribution and can be switched in linkage;

[0011] A drying mechanism is provided on the top of the printing machine body for supplying steam and heat to the main embossing printing assembly and the auxiliary embossing printing assembly respectively;

[0012] The control terminal includes a data acquisition module, a model training module, a data analysis module and an adjustment module;

[0013] A data acquisition module collects historical printing data of the main embossing printing component, the historical printing data including comprehensive printing parameters and printing ink color values;

[0014] Model training module, which trains a machine learning model to predict the future printing ink color value based on comprehensive printing parameters;

[0015] The data analysis module compares and analyzes the predicted future printing ink color value with the ink color threshold corresponding to the main embossing printing component to determine whether to generate a switching control instruction;

[0016] The adjustment module controls the corresponding main embossing printing assembly to stop printing on the workpiece to be printed according to the switching control instruction, and controls the auxiliary embossing printing assembly corresponding to the main embossing printing assembly to print on the workpiece to be printed at a preset time node.

[0017] Furthermore, the main embossing printing assembly and the auxiliary embossing printing assembly both include a plate roller, an impression roller and an ink tank. The ink tank is fixedly arranged on the printing frame, the plate roller is rotatably arranged on the printing frame, the plate roller is located above the impression roller, and the impression roller is movably arranged on the inner wall of the ink tank. The impression roller is connected to the second motor through a rotating shaft. The printing frame is provided with a hydraulic cylinder for driving the impression roller to rise and fall on the inner wall of the ink tank, and the inner wall of the ink tank is elastically provided with a scraper that contacts the impression roller.

[0018] Furthermore, the drying mechanism includes a steam generator arranged on the top of the printing body, a steam duct is provided on the steam outlet side of the steam generator, and a number of steam branches are provided on the steam duct, each steam branch is provided with a main drying chamber and an auxiliary drying chamber distributed up and down, each steam branch is provided with an electromagnetic three-way valve for controlling the flow of steam in the main drying chamber and the auxiliary drying chamber, and the inner walls of the main drying chamber and the auxiliary drying chamber are provided with orifice plates parallel to the workpiece to be printed.

[0019] Furthermore, low-position guide rollers are provided at the inlet ends of the drying bin and the auxiliary drying bin, and high-position guide rollers are provided at the outlet ends of the main drying bin and the auxiliary drying bin. The low-position guide rollers and the high-position guide rollers are both rotatably connected to the printing frame, and a balancing guide roller is rotatably provided on the printing frame, which is at the same horizontal height as the low-position guide roller in the auxiliary embossing printing assembly.

[0020] Furthermore, the data acquisition module includes a liquid level sensor, a vibration sensor, a first temperature sensor, a first gas flow meter, a second temperature sensor, a second gas flow meter, a camera and a photoelectric speed sensor, wherein the liquid level sensor is arranged on the inner wall of the vertical end of the ink tank, the vibration sensor is arranged inside the printing roller, the first temperature sensor and the first gas flow meter are both arranged on the inner wall of the steam outlet side of the steam generator, the second temperature sensor and the second gas flow meter are both arranged on the inner wall of the steam inlet side of the main drying tank and the auxiliary drying tank, the camera is fixedly installed on the printing frame and is located at the outlet end of the main drying tank and the auxiliary drying tank, and the photoelectric speed sensor is fixedly installed on the outer wall of the ink tank in the main embossing printing assembly.

[0021] Furthermore, the comprehensive printing parameters include drum vibration data, ink remaining data, steam temperature loss value and steam flow loss value;

[0022] The training method for the machine learning model to predict the printing ink color value at the future time includes:

[0023] Preset the prediction time step K, sliding step P, and sliding window length N; use the sliding window method to convert the historical printing data into multiple training samples, one training sample corresponds to one label, and constitutes a set of training data, and multiple sets of training data constitute a training set;

[0024] The training set is used as the input of the machine learning model, and the printing ink color value at the future moment after the time step K is predicted as the output. The subsequent printing ink color value of each training set is used as the prediction target. The prediction accuracy is used as the training target to train the machine learning; a machine learning model is generated to predict the printing ink color value at the future moment based on the comprehensive printing parameters.

[0025] Furthermore, the method for determining whether to generate a switching control instruction includes:

[0026] The main embossing printing components in the i printing mechanism are numbered, and the ink color threshold of the i main embossing printing components is preset as MSZ yzi , the predicted printing ink color value at the future moment i is recorded as MSZ wli ;

[0027] When MSZ wli Smaller than MSZ yzi When , a switching control instruction is generated;

[0028] When MSZ wli Greater than or equal to MSZ yzi When , no switching control instruction is generated.

[0029] Furthermore, the switching control instruction includes: controlling the hydraulic cylinder in the main embossing printing assembly to drive the impression roller to move downward in the ink tank so that the impression roller in the main embossing printing assembly does not contact the workpiece to be printed, and then controlling the hydraulic cylinder in the auxiliary embossing printing assembly to drive the impression roller to move upward in the ink tank so that the impression roller in the auxiliary embossing printing assembly contacts the lower surface of the workpiece to be printed;

[0030] While the hydraulic cylinder in the main embossing printing assembly drives the impression roller downward, the electromagnetic three-way valve is activated, closing the hot steam channel of the steam branch pipe to the main drying bin and opening the hot steam channel of the steam branch pipe to the auxiliary drying bin.

[0031] Furthermore, the method for obtaining the preset time node includes:

[0032] The transmission speed of the printed piece during printing is monitored by a photoelectric speed sensor provided on the ink reservoir in the main embossing printing assembly;

[0033] Obtain the transmission distance of the printed piece from the main embossing printing assembly to the auxiliary embossing printing assembly through the design drawings of the printing equipment;

[0034] Combining the transmission distance and the transmission speed, the transmission time of the printed piece from the main embossing printing assembly to the auxiliary embossing printing assembly is obtained according to the formula;

[0035] The expression for transmission time is:

[0036] Where T is the transmission time, S is the transmission distance, and V is the transmission speed;

[0037] The time node when the printed piece leaves the primary embossing printing assembly is T1, and the preset time node when the printed piece enters the secondary embossing printing assembly is T1+T.

[0038] A printing method for a synchronous plate-registered embossed decorative paper printing device is implemented based on the synchronous plate-registered embossed decorative paper printing device, comprising:

[0039] S1: The workpiece to be printed on the unwinding rack is passed through the main embossing printing assembly, main drying chamber, auxiliary embossing printing assembly and auxiliary drying chamber on each printing rack from bottom to top, and then wound up and fixed on the rewinding rack. The main embossing printing assembly and main drying chamber first print the workpiece;

[0040] S2: Collect historical printing data from the main embossing printing component. The historical printing data includes printing comprehensive parameters and printing ink color values. Based on the printing comprehensive parameters, a machine learning model is trained to predict the printing ink color values ​​at future moments.

[0041] S3: Predicting the future printing ink color value based on the trained machine learning model, comparing the predicted future printing ink color value with the ink color threshold corresponding to the main embossing printing component, and determining whether to generate a switching control instruction;

[0042] S4: controlling the corresponding main embossing printing assembly to stop printing on the workpiece to be printed according to the switching control instruction, and controlling the auxiliary embossing printing assembly corresponding to the main embossing printing assembly to print on the workpiece to be printed at a preset time node;

[0043] S5: traverse all main embossing printing components and repeat S2-S4.

[0044] The technical effects and advantages of the synchronous registration embossed decorative paper printing equipment and printing method of the present invention are as follows:

[0045] 1. The present invention collects comprehensive printing data and combines it with a machine learning model to predict the ink color value of printing at a future moment. The ink color value of printing at a future moment is compared with the preset ink color threshold value corresponding to the main embossed printing component to determine whether to generate a switching control instruction. This can enable the printing failure of the main embossed printing component to be discovered in advance and accurately, and the switching control instruction to be issued in advance to automatically switch the working status of the main embossed printing component and the auxiliary embossed printing component, thereby avoiding printing accidents and improving printing quality.

[0046] 2. The present invention sets two interconnected main embossing printing components and auxiliary embossing printing components in each printing mechanism, which can automatically and flexibly control the working status of the main embossing printing component and the auxiliary embossing printing component. When the main embossing printing component needs to be repaired, the auxiliary embossing printing component can be started at a preset time node without stopping the machine, and seamlessly print the workpiece to be printed, thereby achieving the working effect of mutual coordination between the main embossing printing component and the auxiliary embossing printing component, and improving the working efficiency of the printing equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 Schematic diagram of a synchronous registration embossed decorative paper printing device according to Example 1 of the present invention;

[0048] Figure 2 Schematic diagram of the drying mechanism in Example 1 of the present invention;

[0049] Figure 3 Schematic top view of the main drying chamber in Example 1 of the present invention;

[0050] Figure 4 Schematic diagram of the printing mechanism in Example 1 of the present invention;

[0051] Figure 5 Schematic diagram of the connection between the impression cylinder and the ink reservoir in Example 1 of the present invention;

[0052] Figure 6 This is a schematic side view of the interior of the ink tank in Example 1 of the present invention;

[0053] Figure 7 This is a schematic diagram of the modules in Example 1 of the present invention;

[0054] Figure 8 This is a flow chart of the printing method of the synchronous registration embossed decorative paper printing equipment in Example 2 of the present invention.

[0055] Description of reference numerals:

[0056] 1. Unwinding rack; 2. Ladder; 3. Rewinding rack; 4. Printing machine body; 5. Drying mechanism; 51. Steam generator; 52. Steam duct; 53. Solenoid three-way valve; 54. Steam branch pipe; 55. Main drying chamber; 551. Second temperature sensor; 552. Second gas flowmeter; 553. Orifice plate; 56. First temperature sensor; 57. First gas flowmeter; 58. Auxiliary drying chamber; 6. Printing mechanism; 61. Printing frame; 600. Main embossing printing assembly; 62. Plate cylinder; 63. Impression cylinder; 64. Ink tank; 641. Liquid level sensor; 642. Second motor; 643. Rotating shaft; 644. Hydraulic cylinder; 645. Vibration sensor; 646. Doctor blade; 65. Low guide roller; 66. High guide roller; 67. Balancing guide roller; 68. Camera; 69. Photoelectric speed sensor; 601. Auxiliary embossing printing assembly. DETAILED DESCRIPTION

[0057] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0058] Example 1

[0059] See also Figure 1-Figure 7 As shown, the synchronous registration embossed decorative paper printing device of this embodiment includes a printing body 4, a reel-out rack 1, a reel-up rack 3 and a control terminal. A ladder 2 is provided on the printing body 4:

[0060] like Figure 1As shown, a plurality of printing mechanisms 6 are arranged at intervals on the printing machine body 4, and each printing mechanism 6 is equipped with a printing station for personnel to perform printing operations;

[0061] The unwinding rack 1 unwinds the workpiece to be printed and guides it into the printing mechanism 6 at the starting end. The workpiece to be printed is continuously transported and printed in several printing mechanisms 6. The rewinding rack 3 rewinds the workpiece to be printed and guides it out of the printing mechanism 6 at the terminal end.

[0062] like Figure 4 As shown, the printing mechanism 6 includes a printing frame 61, on which a main embossing printing assembly 600 and a secondary embossing printing assembly 601 are arranged in an upper and lower distribution and can be switched in a linked manner. The workpiece to be printed on the unwinding frame 1 will first enter the main embossing printing assembly 600 in the starting printing mechanism 6, and then enter the secondary embossing printing assembly 601, and then enter the secondary embossing printing assembly 601 in the printing mechanism 6 to the main embossing printing assembly 600 in the next printing mechanism 6, and so on, until the workpiece to be printed passes through the main embossing printing assembly 600 and the secondary embossing printing assembly 601 in all the printing mechanisms 6, and is then wound up and fixed by the winding frame 3;

[0063] like Figure 4 and Figure 5 As shown, the main embossing printing assembly 600 and the auxiliary embossing printing assembly 601 both include a plate cylinder 62, an impression cylinder 63 and an ink tank 64. The ink tank 64 is fixedly arranged on the printing frame 61, and the plate cylinder 62 is rotatably arranged on the printing frame 61. The plate cylinder 62 is located above the impression cylinder 63. The impression cylinder 63 is movably arranged on the inner wall of the ink tank 64. The impression cylinder 63 is connected to the second motor 642 through a rotating shaft 643. A hydraulic cylinder 644 is provided on the printing frame 61 to drive the impression cylinder 63 to rise and fall on the inner wall of the ink tank 64. The brush passes through the gap between the impression cylinder 63 and the plate cylinder 62. The second motor 642 drives the impression cylinder 63 to rotate via the rotating shaft 643. When the impression cylinder 63 rotates, the ink in the ink reservoir 64 is dipped onto the surface. The ink is rolled onto the lower surface of the workpiece to be printed and then the workpiece is subjected to the first registration and embossing printing process. At the same time, the plate cylinder 62 rotates synchronously with the impression cylinder 63 in the opposite direction under the friction transmission of the workpiece to be printed, performing a rolling process on the workpiece to be printed, ensuring that the workpiece to be printed can be stably conveyed forward.

[0064] like Figure 6 As shown, the inner wall of the ink reservoir 64 is elastically provided with a scraper 646 in contact with the impression cylinder 63. When the impression cylinder 63 rotates to print, the scraper 646 scrapes and contacts the outer wall of the impression cylinder 63, thereby scraping and smoothing the ink on the impression cylinder 63, maintaining a uniform thickness of the ink on the impression cylinder 63, and improving the printing quality of the impression cylinder 63 on the workpiece to be printed.

[0065] When the hydraulic cylinder 644 drives the impression roller 63 to move downward in the ink tank 64, the impression roller 63 will not contact the lower surface of the workpiece to be printed. At this time, the embossing printing assembly where the impression roller 63 is located is in an idle state and will not perform embossing printing on the workpiece to be printed. By adjusting the height of the impression roller 63 in the main embossing printing assembly 600 and the auxiliary embossing printing assembly 601 in the same printing mechanism 6, the working states of the main embossing printing assembly 600 and the auxiliary embossing printing assembly 601 can be automatically switched, so that the main embossing printing assembly 600 and the auxiliary embossing printing assembly 601 can perform continuous and seamless printing on the workpiece to be printed without shutting down the printing equipment, thereby improving the working efficiency of the printing equipment and ensuring printing quality.

[0066] like Figure 1-Figure 4 As shown, a drying mechanism 5 is provided on the top of the printing machine body 4 for supplying steam and heat to the main embossing printing assembly 600 and the auxiliary embossing printing assembly 601 respectively;

[0067] The drying mechanism 5 includes a steam generator 51 arranged on the top of the printing machine body 4, a steam pipe 52 is provided on the steam outlet side of the steam generator 51, and a plurality of steam branches 54 are provided on the steam pipe 52, and each steam branch 54 is provided with a main drying chamber 55 and a sub-drying chamber 58 distributed up and down, a main drying chamber 55 and a sub-drying chamber 58 respectively corresponding to a main embossing printing component 600 and a sub-embossing printing component 601, and each steam branch 54 is provided with a control for controlling the steam flow in the main drying chamber 55 and the sub-drying chamber 58. The electromagnetic three-way valve 53 is dynamically switched on and off. The inner walls of the main drying chamber 55 and the auxiliary drying chamber 58 are both provided with orifice plates 553 parallel to the workpieces to be printed. The steam generator 51 generates high-temperature and high-pressure hot steam, which enters the steam branch pipe 54 through the steam conduit 52 and eventually flows into the main drying chamber 55 and the auxiliary drying chamber 58. The hot steam then flows outward evenly and smoothly through the orifice plates 553 toward the workpieces to be printed, thus providing a high-temperature drying treatment for the workpieces to be printed in the main drying chamber 55 and the auxiliary drying chamber 58, allowing the ink on the workpieces to be dried quickly.

[0068] like Figure 2 and Figure 4 As shown, each steam branch pipe 54 is provided with an electromagnetic three-way valve 53 for controlling the flow of steam in the main drying chamber 55 and the auxiliary drying chamber 58. By switching the channel conduction state of the electromagnetic three-way valve 53, the flow of hot steam in the main drying chamber 55 and the auxiliary drying chamber 58 can be controlled, so that the main drying chamber 55 and the auxiliary drying chamber 58 can cooperate with the corresponding main embossing printing component 600 and a auxiliary embossing printing component 601 to perform high-temperature drying treatment.

[0069] like Figure 4As shown, the inlet ends of the main drying chamber 55 and the auxiliary drying chamber 58 are both provided with low guide rollers 65, and the outlet ends of the main drying chamber 55 and the auxiliary drying chamber 58 are both provided with high guide rollers 66. The low guide rollers 65 and the high guide rollers 66 are both rotatably connected to the printing frame 61. After printing, the workpiece to be printed will first roll in contact with the low guide rollers 65, and then roll upward in contact with the high guide rollers 66, which can guide the workpiece to be printed upward, so that the workpiece to be printed can still maintain the tensioning device after changing direction and enter the next embossing printing assembly;

[0070] like Figure 4 As shown, a balancing guide roller 67 is rotatably provided on the printing frame 61 and is at the same horizontal height as the low-position guide roller 65 in the auxiliary embossing printing assembly 601, so that the workpiece to be printed can still maintain a horizontal state and rolling contact with the embossing roller 63 in the auxiliary embossing printing assembly 601 after the workpiece to be printed is reversed and transported from the main embossing printing assembly 600 to the auxiliary embossing printing assembly 601, thereby ensuring the stability of the state of the workpiece to be printed during the printing process.

[0071] like Figure 7 As shown, the control terminal includes a data acquisition module, a model training module, a data analysis module and an adjustment module, and the control terminal is fixedly arranged on the printing machine body 4;

[0072] A data acquisition module collects historical printing data of the main embossing printing assembly 600, wherein the historical printing data includes comprehensive printing parameters and printing ink color values. The comprehensive printing parameters include drum vibration data, ink remaining data, steam temperature loss value, and steam flow loss value.

[0073] The drum vibration data refers to the vibration amplitude of the impression drum 63 during its rotation during printing. A larger vibration amplitude of the impression drum 63 may cause uneven ink distribution on the decorative paper, resulting in ink spots or ink color deviation, and a smaller ink color value on the printed workpiece. The drum vibration data is monitored and acquired by a vibration sensor 645 disposed within the impression drum 63.

[0074] The remaining ink level data reflects the level of ink in the ink reservoir 64. When the ink level in the ink reservoir 64 is low, the ink reservoir 64 is affected by the vibration of the printing equipment, causing the ink level to fluctuate unevenly. In this case, the impression cylinder 63 is prone to uneven ink absorption, resulting in a smaller ink color value on the printed workpiece. The remaining ink level data is monitored and acquired by the level sensor 641 installed in the ink reservoir 64.

[0075] The steam temperature loss value refers to the difference between the initial steam temperature output by the steam generator 51 and the final steam temperature entering the main drying chamber 55. The larger the steam temperature loss value, the greater the temperature loss of the steam during the flow process. At this time, the steam temperature value in the main drying chamber 55 will also be lower, resulting in insufficient drying temperature for the printed ink on the printed workpiece, and the ink color value of the printed workpiece will be smaller.

[0076] Methods for obtaining steam temperature loss values ​​include:

[0077] The first temperature sensor 56 provided on the inner wall of the steam outlet side of the steam generator 51 obtains p instantaneous initial temperatures, and the p instantaneous initial temperatures are added and averaged to obtain the initial steam temperature;

[0078] The expression for the initial steam temperature is:

[0079] Where, WD cs is the initial steam temperature, T1 i is the i-th instantaneous initial temperature;

[0080] The second temperature sensor 551 provided on the inner wall of the steam inlet side of the main drying chamber 55 obtains n instantaneous terminal temperatures, and the n instantaneous terminal temperatures are added and averaged to obtain the terminal steam temperature;

[0081] The expression for the terminal steam temperature is:

[0082] Where, WD cs is the terminal steam temperature, T2 i is the i-th instantaneous terminal temperature;

[0083] The expression of steam temperature loss value is: WD ss =WD cs -WD zd ;

[0084] Where, WD ss is the steam temperature loss value;

[0085] The steam flow loss value refers to the difference between the initial steam flow rate output by the steam generator 51 and the final steam flow rate entering the main drying chamber 55. When the steam flow loss value is larger, it means that the flow loss during the steam flow process is greater. At this time, the steam flow rate entering the main drying chamber 55 will be smaller, resulting in insufficient steam flow to dry the ink printed on the print, and the ink color value of the print will be smaller.

[0086] Methods for obtaining steam flow loss values ​​include:

[0087] The initial steam flow value derived from the steam generator 51 within a unit time is monitored by a first gas flow meter 57 provided on the inner wall of the steam outlet side of the steam generator 51;

[0088] The second gas flow meter 552 provided on the inner wall of the steam inlet side of the main drying chamber 55 monitors the terminal steam flow value flowing into the main drying chamber 55 within a unit time, and the steam flow loss value is obtained by subtracting the initial steam flow value from the terminal steam flow value;

[0089] By obtaining the steam flow loss value, we can accurately understand the loss of steam flow during transmission, and thus accurately understand the utilization rate of steam flow in a certain period of time. Compared with measuring the instantaneous steam flow data at a specific point, it is more representative and can avoid the random error caused by the instantaneous steam flow measurement at a specific point.

[0090] The printing ink color value is the CMYK color value corresponding to each color after the decorative paper is embossed and printed in different colors. Each different color corresponds to a different CMYK color value. Therefore, after the decorative paper is embossed and printed, the pattern on the decorative paper will show different printing ink color values, which can provide a basis for comparing and judging the quality of the embossed printing on the decorative paper. For example, the CMYK color values ​​of dark green are: c = 90, m = 70, y = 100, and k = 60;

[0091] Methods for obtaining printing ink color values ​​include:

[0092] The camera 68 disposed on the printing frame 61 and located at the exit end of the main drying chamber 55 captures the printing pattern image on the workpiece to be printed, marks the center point of the printing pattern image, and draws a circle with a radius of one-quarter of the width of the printing pattern image with the center point as the base point to obtain a selected circular image. K marking points are marked at equal angles in a circle at half the radius of the selected circular image.

[0093] Import the selected circular image into the image processing software of the printing device control terminal, such as Adobe Photoshop, and use the built-in color calculation module to calculate the CMYK color values ​​of each of the k marking points in sequence, and then add the k CMYK color values ​​to obtain the printing ink color value.

[0094] Model training module, which trains a machine learning model to predict the future printing ink color value based on comprehensive printing parameters;

[0095] Methods for training machine learning models that predict future printing ink color values ​​include;

[0096] The printing comprehensive parameters are used as the input of the multi-feature time series prediction machine learning model, and the future printing ink color value is used as the output of the multi-feature time series prediction machine learning model. The future printing ink color value is used as the prediction target, and the training goal is to minimize the sum of the prediction accuracy of all training data. The multi-feature time series prediction machine learning model is trained until the sum of the prediction accuracy reaches convergence and the training is stopped;

[0097] The loss function value of the machine learning model is the mean square error;

[0098] Mean square error is one of the commonly used loss functions. Minimization is used to train the model so that the machine learning model better fits the data, thereby improving the performance and accuracy of the model;

[0099] In the loss function, MSE is the loss function value of the machine learning model, x is the feature vector group number; m is the number of feature vector groups; y x is the future printing ink color value corresponding to the xth group of eigenvectors, is the future printing ink color value actually corresponding to the xth group of eigenvectors;

[0100] Other model parameters of the machine learning model, such as the target loss value, optimization algorithm, the ratio of the training set, test set, and validation set, and the optimization of the loss function, are all obtained through actual engineering implementation and continuous experimental tuning.

[0101] Methods for predicting the color value of printing ink at a future time include:

[0102] Preset the prediction time step K, sliding step P, and sliding window length N; use the sliding window method to convert historical printing data into multiple training samples, where each training sample corresponds to a label and constitutes a set of training data. Multiple sets of training data constitute a training set. The training set is used as the input of the machine learning model, and the printing ink color value at the future moment after the time step K is predicted as the output. The subsequent printing ink color value of each training set is used as the prediction target. The prediction accuracy is used as the training target to train the machine learning; generate a machine learning model that predicts the printing ink color value at the future moment based on the comprehensive printing parameters;

[0103] Specifically, a simple example of the sliding window method is as follows: suppose you want to use the historical printed data packets 1, 2, 3, 4, 5, 6, 7 to train a time prediction model to predict the value of one time step in the future. You can use a sliding window of length 4 and a sliding step of length 1 to generate the predicted future training set and prediction target. For example, the training set is 1, 2, 3, 4, 2, 3, 4, 5 and 3, 4, 5, 6, and the prediction target is 5, 6 and 7;

[0104] The sliding window method can be used to accurately and in advance predict the printing ink color value at a future moment based on the existing historical printing data packets in the selected scheduling area, so that when the printed parts are being printed, the poor printing quality of the printed parts can be discovered in advance, and accurate data support can be provided for the control terminal of the subsequent printing equipment to generate and send printing component switching instructions, without any lag in printing fault monitoring.

[0105] The data analysis module compares and analyzes the predicted future printing ink color value with the ink color threshold corresponding to the main embossing printing component 600 to determine whether to generate a switching control instruction;

[0106] The main embossing printing components 600 in the i printing mechanism 6 are numbered, and the ink color threshold of the i main embossing printing components 600 is preset, and is recorded as MSZ yzi Since each primary embossing printing assembly 600 prints different patterns and colors on a workpiece, the ink color values ​​of the patterns on the workpiece after being printed by each primary embossing printing assembly 600 are different. The specific value of each ink color threshold is set by collecting multiple sets of sample data of ink color values ​​of the workpiece to be printed and setting them after multiple debugging. This allows each ink color threshold to correspond to the printing quality of the primary embossing printing assembly 600 at that location, and thus to judge the printing quality of the workpiece by the primary embossing printing assembly 600.

[0107] The predicted printing ink color value at the future moment i is recorded as MSZ wli And record the ink color value of i future moments as MSZ wli Compare with the ink color thresholds of the corresponding i primary embossing printing components 600 respectively;

[0108] When MSZ wli Smaller than MSZ yzi When , it indicates that the printing quality of the workpiece to be printed after printing by the i-th main embossing printing assembly 600 is low, and a switching control instruction is generated;

[0109] When MSZ wli Greater than or equal to MSZ yzi When , it indicates that the printing quality of the workpiece to be printed after printing by the i-th main embossing printing assembly 600 is high, and no switching control instruction is generated;

[0110] The adjustment module controls the corresponding primary embossing printing assembly 600 to stop printing on the workpiece to be printed according to the switching control instruction, and controls the secondary embossing printing assembly 601 corresponding to the primary embossing printing assembly 600 to print on the workpiece to be printed at a preset time node;

[0111] The switching control instructions include: controlling the hydraulic cylinder 644 in the main embossing printing assembly 600 to drive the impression roller 63 to move downward in the ink reservoir 64 so that the impression roller 63 in the main embossing printing assembly 600 does not contact the workpiece to be printed; then controlling the hydraulic cylinder 644 in the auxiliary embossing printing assembly 601 to drive the impression roller 63 to move upward in the ink reservoir 64 so that the impression roller 63 in the auxiliary embossing printing assembly 601 contacts the lower surface of the workpiece to be printed, thereby performing printing processing on the workpiece;

[0112] When the hydraulic cylinder 644 in the main embossing printing assembly 600 drives the impression cylinder 63 downward, the electromagnetic three-way valve 53 is activated, closing the hot steam passage from the steam branch pipe 54 to the main drying chamber 55 and opening the hot steam passage from the steam branch pipe 54 to the auxiliary drying chamber 58. This allows the main embossing printing assembly 600 to be switched to the auxiliary embossing printing assembly 601 in a timely manner when the printing quality is low, and also avoids interruption when switching between the main embossing printing assembly 600 and the auxiliary embossing printing assembly 601, thereby preventing interruption and downtime of the printing equipment.

[0113] Since there is a certain distance between the main embossing printing assembly 600 and the secondary embossing printing assembly 601, when the workpiece to be printed is separated from the main embossing printing assembly 600 and enters the secondary embossing printing assembly 601 for printing, it is necessary to ensure that the printing position on the workpiece to be printed can be seamlessly connected with the impression roller 63 on the secondary embossing printing assembly 601 to avoid dislocation and confusion of the printed pattern. Therefore, after the workpiece to be printed is separated from the main embossing printing assembly 600, the secondary embossing printing assembly 601 is started at a preset time node so that the impression roller 63 in the secondary embossing printing assembly 601 can seamlessly connect with the workpiece to be printed;

[0114] Methods for obtaining preset time nodes include:

[0115] The transport speed of the printed piece during printing is monitored by a photoelectric speed sensor 69 provided on the ink reservoir 64 in the main embossing printing assembly 600;

[0116] The transmission distance of the workpiece to be printed from the main embossing printing assembly 600 to the secondary embossing printing assembly 601 is obtained from the design drawings of the printing equipment. The transmission distance is specifically composed of: the sum of the distance between the impression cylinder 63 in the main embossing printing assembly 600 and the low guide roller 65, the distance between the low guide roller 65 and the matching high guide roller 66, the distance between the high guide roller 66 and the balancing guide roller 67, and the distance between the balancing guide roller 67 and the impression cylinder 63 in the secondary embossing printing assembly 601;

[0117] Combining the transmission distance and transmission speed, the transmission time of the printed piece from the main embossing printing assembly 600 to the auxiliary embossing printing assembly 601 can be obtained according to the formula;

[0118] The expression for transmission time is:

[0119] Where T is the transmission time, S is the transmission distance, and V is the transmission speed;

[0120] The time node when the workpiece to be printed leaves the main embossing printing component 600 is marked as T1, and the preset time node when the workpiece to be printed enters the secondary embossing printing component 601 is T1+T, that is, when the workpiece to be printed is separated from the main embossing printing component 600 and after a time of T, the embossing roller 63 in the secondary embossing printing component 601 is started at the preset time node of T1+T, and the workpiece to be printed can be seamlessly printed to ensure the printing quality of the workpiece to be printed.

[0121] In this embodiment, by arranging two interconnected main embossing printing components 600 and auxiliary embossing printing components 601 in each printing mechanism, the working status of the main embossing printing component 600 and the auxiliary embossing printing component 601 can be automatically and flexibly controlled, so that when the main embossing printing component 600 needs to be repaired, the auxiliary embossing printing component 601 can be started at a preset time node without stopping the machine, and seamlessly print the workpiece to be printed, thereby achieving the working effect of the main embossing printing component 600 and the auxiliary embossing printing component 601 coordinating with each other, which can not only avoid the poor printing quality of the workpiece to be printed in advance, but also can timely perform the linkage switching of the main embossing printing component 600 and the auxiliary embossing printing component 601, thereby improving the printing quality of the printing equipment.

[0122] Example 2

[0123] See also Figure 8 As shown, for parts not described in detail in this embodiment, please refer to the description of embodiment 1. A printing method for a synchronous registration embossed decorative paper printing device is provided, comprising:

[0124] S1: The workpiece on the unwinding rack 1 passes through the main embossing printing assembly 600, the main drying chamber 55, the auxiliary embossing printing assembly 601 and the auxiliary drying chamber 58 on each printing rack 61 in sequence from bottom to top, and is then wound and fixed by the rewinding rack 3. The main embossing printing assembly 600 and the main drying chamber 55 first perform printing on the workpiece.

[0125] S2: Collecting historical printing data from the primary embossing printing assembly 600, the historical printing data including comprehensive printing parameters and printing ink color values, and training a machine learning model based on the comprehensive printing parameters to predict future printing ink color values;

[0126] S3: Predicting the future printing ink color value based on the trained machine learning model, comparing the predicted future printing ink color value with the ink color threshold corresponding to the main embossing printing component 600, and determining whether to generate a switching control instruction;

[0127] S4: controlling the corresponding primary embossing printing assembly 600 to stop printing on the workpiece to be printed according to the switching control instruction, and controlling the secondary embossing printing assembly 601 corresponding to the primary embossing printing assembly 600 to print on the workpiece to be printed at a preset time node;

[0128] S5: traverse all primary embossing printing components 600 and repeat S2-S4.

[0129] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. Synchronous registration embossed decorative paper printing equipment, characterized by: It includes a printing machine body (4), a roll-unwinding frame (1), a roll-rewinding frame (3) and a control terminal; A plurality of printing mechanisms (6) are arranged at intervals on the printing machine body (4); The unwinding frame (1) unwinds the workpiece to be printed and guides it into the printing mechanism (6) located at the starting end. The workpiece to be printed is continuously transported and printed in a plurality of the printing mechanisms (6). The rewinding frame (3) rewinds the workpiece to be printed and guides it out of the printing mechanism (6) located at the terminal end. The printing mechanism (6) comprises a printing frame (61), on which a main embossing printing assembly (600) and a secondary embossing printing assembly (601) are arranged in an upper and lower distribution and can be switched in linkage; A drying mechanism (5) is provided on the top of the printing machine body (4) for supplying steam and heat to the main embossing printing component (600) and the auxiliary embossing printing component (601) respectively; The control terminal includes a data acquisition module, a model training module, a data analysis module and an adjustment module; A data collection module for collecting historical printing data of the main embossing printing component (600), the historical printing data including comprehensive printing parameters and printing ink color values; The comprehensive printing parameters include drum vibration data, ink remaining data, steam temperature loss value and steam flow loss value; The training method for the machine learning model to predict the printing ink color value at the future time includes: Preset forecast time step , sliding step And the sliding window length ; The historical printing data is converted into multiple training samples using the sliding window method. One training sample corresponds to one label and constitutes a set of training data. Multiple sets of training data constitute a training set. Use the training set as input to the machine learning model and predict the time step The future printing ink color value is used as the output, the subsequent printing ink color value of each training set is used as the prediction target, and the prediction accuracy is used as the training target to train the machine learning; a machine learning model is generated to predict the future printing ink color value based on the printing comprehensive parameters; Model training module, which trains a machine learning model to predict the future printing ink color value based on comprehensive printing parameters; A data analysis module compares and analyzes the predicted printing ink color value at a future moment with the ink color threshold value corresponding to the main embossing printing component (600) to determine whether to generate a switching control instruction; The method for determining whether to generate a switching control instruction includes: Will The main embossing printing components (600) in each printing mechanism (6) are numbered and preset The ink color threshold of the primary embossed printing component (600) is recorded as ,Will The predicted future printing ink color value is recorded as ; when Less than , generating a switching control instruction; when Greater than or equal to , no switching control instruction is generated; The adjustment module controls the corresponding main embossing printing component (600) to stop printing on the to-be-printed piece according to the switching control instruction, and controls the secondary embossing printing component (601) corresponding to the main embossing printing component (600) to print on the to-be-printed piece at a preset time node.

2. The synchronous registration embossed decorative paper printing device according to claim 1, characterized in that: The main embossing printing assembly (600) and the auxiliary embossing printing assembly (601) both include a plate cylinder (62), an impression cylinder (63) and an ink tank (64). The ink tank (64) is fixedly arranged on the printing frame (61). The plate cylinder (62) is rotatably arranged on the printing frame (61). The plate cylinder (62) is located above the impression cylinder (63). The impression cylinder (63) is movably arranged on the inner wall of the ink tank (64). The impression cylinder (63) is connected to the second motor (642) via a rotating shaft (643). A hydraulic cylinder (644) is provided on the printing frame (61) for driving the impression cylinder (63) to rise and fall on the inner wall of the ink tank (64). The inner wall of the ink tank (64) is elastically provided with a scraper (646) in contact with the impression cylinder (63).

3. The synchronous registration embossed decorative paper printing device according to claim 2, characterized in that: The drying mechanism (5) includes a steam generator (51) arranged on the top of the printing machine body (4), a steam conduit (52) is provided on the steam outlet side of the steam generator (51), and a plurality of steam branch pipes (54) are provided on the steam conduit (52), each steam branch pipe (54) is provided with a main drying chamber (55) and an auxiliary drying chamber (58) distributed up and down, each steam branch pipe (54) is provided with an electromagnetic three-way valve (53) for controlling the flow of steam in the main drying chamber (55) and the auxiliary drying chamber (58), and the inner walls of the main drying chamber (55) and the auxiliary drying chamber (58) are provided with a hole plate (553) parallel to the workpiece to be printed.

4. The synchronous registration embossed decorative paper printing device according to claim 3, characterized in that: The inlet ends of the main drying chamber (55) and the auxiliary drying chamber (58) are both provided with low-position guide rollers (65), and the outlet ends of the main drying chamber (55) and the auxiliary drying chamber (58) are both provided with high-position guide rollers (66). The low-position guide rollers (65) and the high-position guide rollers (66) are both rotatably connected to the printing frame (61). The printing frame (61) is rotatably provided with a balancing guide roller (67) at the same level as the low-position guide roller (65) in the auxiliary embossing printing assembly (601).

5. The synchronous registration embossed decorative paper printing device according to claim 4, characterized in that: The data acquisition module includes a liquid level sensor (641), a vibration sensor (645), a first temperature sensor (56), a first gas flow meter (57), a second temperature sensor (551), a second gas flow meter (552), a camera (68) and a photoelectric speed sensor (69), wherein the liquid level sensor (641) is arranged on the inner wall of the vertical end of the ink bin (64), the vibration sensor (645) is arranged inside the impression roller (63), the first temperature sensor (56) and the first gas flow meter (57) are both arranged on the inner wall of the steam outlet side of the steam generator (51), the second temperature sensor (551) and the second gas flow meter (552) are both arranged on the inner wall of the steam inlet side of the main drying bin (55) and the auxiliary drying bin (58), the camera (68) is fixedly mounted on the printing frame (61) and is located at the outlet end of the main drying bin (55) and the auxiliary drying bin (58), and the photoelectric speed sensor (69) is fixedly mounted on the outer wall of the ink bin (64) in the main embossing printing assembly (600).

6. The synchronous registration embossed decorative paper printing device according to claim 1, characterized in that: The switching control instruction includes: controlling the hydraulic cylinder (644) in the main embossing printing assembly (600) to drive the impression roller (63) to move downward in the ink bin (64), so that the impression roller (63) in the main embossing printing assembly (600) does not contact the workpiece to be printed; and then controlling the hydraulic cylinder (644) in the auxiliary embossing printing assembly (601) to drive the impression roller (63) to move upward in the ink bin (64), so that the impression roller (63) in the auxiliary embossing printing assembly (601) contacts the lower surface of the workpiece to be printed; When the hydraulic cylinder (644) in the main embossing printing assembly (600) drives the impression roller (63) to move downward, the electromagnetic three-way valve (53) is activated, closing the hot steam passage of the steam branch pipe (54) to the main drying chamber (55) and opening the hot steam passage of the steam branch pipe (54) to the auxiliary drying chamber (58).

7. The synchronous registration embossed decorative paper printing device according to claim 6, characterized in that: The method for obtaining the preset time node includes: The transmission speed of the printed piece during printing is monitored by a photoelectric speed sensor (69) provided on the ink reservoir (64) in the main embossing printing assembly (600); Obtaining the transmission distance of the workpiece to be printed from the main embossing printing assembly (600) to the secondary embossing printing assembly (601) through the design drawings of the printing equipment; Combining the transmission distance and the transmission speed, the transmission time of the workpiece to be printed from the main embossing printing assembly (600) to the auxiliary embossing printing assembly (601) is obtained according to a formula; The expression for transmission time is: ; Where, is the transmission time, is the transmission distance, is the transmission speed; The time point when the printed piece leaves the main embossing printing assembly (600) is marked as , then the preset time node for the printed piece to enter the secondary embossing printing assembly (601) is .

8. A printing method for a synchronously registered embossed decorative paper printing device, implemented based on the synchronously registered embossed decorative paper printing device according to any one of claims 3 to 7, characterized in that: include: S1: After the workpiece to be printed on the unwinding rack (1) passes through the main embossing printing assembly (600), the main drying chamber (55), the auxiliary embossing printing assembly (601) and the auxiliary drying chamber (58) on each printing rack (61) from bottom to top, it is wound and fixed by the rewinding rack (3), and the main embossing printing assembly (600) and the main drying chamber (55) first perform printing processing on the workpiece to be printed; S2: collecting historical printing data in the main embossing printing component (600), the historical printing data including printing comprehensive parameters and printing ink color values, and training a machine learning model for predicting printing ink color values ​​at future moments based on the printing comprehensive parameters; S3: predicting the ink color value of printing at a future moment based on the trained machine learning model, comparing and analyzing the predicted ink color value of printing at a future moment with the ink color threshold value corresponding to the main embossing printing component (600), and determining whether to generate a switching control instruction; S4: controlling the corresponding main embossing printing component (600) to stop printing on the workpiece to be printed according to the switching control instruction, and controlling the auxiliary embossing printing component (601) corresponding to the main embossing printing component (600) to print on the workpiece to be printed at a preset time node; S5: Traverse all the main embossing printing components (600) and repeat S2-S4.

Images