Self-adaptive humidity adjusting carton printing device and carton printing method thereof

Abstract

The invention discloses a self-adaptive humidity adjusting carton printing device and a carton printing method thereof, belongs to the technical field of carton printing equipment and printing processes, and aims to solve the problems that the printing rejection rate is high, the labor cost is increased, and raw materials are wasted due to the fact that manual judgment and adjustment are needed, response lag exists, and the precision is low. According to the invention, full-breadth scanning is carried out through three or more groups of sensors, subarea compensation is triggered by + / -0.5% humidity difference, the problems of image-text set-off in a high-humidity area, ink layer falling off in a low-humidity area and paperboard embrittlement are avoided, and the full-breadth printing consistency deviation is less than or equal to 2%; and through a closed-loop correction mechanism, accurate landing of ink viscosity, roller pressure, drying temperature and paper feeding speed and the standard reaching rate of ink layer adhesive force are ensured, meanwhile, automatic elimination is conducted when the humidity is larger than 14% or smaller than 6%, production is recovered after reinspection is qualified, the situation that the paperboard exceeding the standard flows into the printing link is avoided, the printing quality is remarkably improved, and the defect rate is greatly reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of carton printing equipment and printing process, more particularly to a self-adaptive humidity adjusting carton printing device and a carton printing method thereof. BACKGROUND

[0002] In the carton printing production, the paperboard humidity is one of the key factors affecting the printing quality. In the conventional carton printing process, the paperboard is easily affected by the environmental temperature and humidity in the production, storage and transportation links, resulting in fluctuations in the humidity of the same batch or even the same paperboard, usually in the range of 5% to 15%. When the paperboard humidity is too high, the paperboard is prone to become soft, the paper feeding positioning is offset, and then the overprint is inaccurate, the ink drying speed is slowed down, and the "dirty" and "ink layer adhesion" are easily caused. When the paperboard humidity is too low, the paperboard is prone to crack due to brittleness, the surface static electricity is enhanced, the paperboard is prone to be dirty due to the adsorption of ink dust, and the ink adhesion is also significantly reduced.

[0003] The existing carton printing equipment usually adopts a "fixed parameter printing" mode, that is, the ink viscosity, pressure, drying temperature and other parameters are preset according to experience, and cannot be adjusted in real time according to the paperboard humidity fluctuations. Although some equipment is equipped with a simple humidity detection function, it can only detect a single point and cannot cover the full width, and lacks closed-loop feedback control, and needs to rely on manual judgment and adjustment, which has the problems of response lag and low precision, resulting in high printing waste rate and increasing labor cost and raw material waste.

[0004] Therefore, a new scheme needs to be proposed to solve this problem. SUMMARY

[0005] In view of the problems in the prior art, the present application aims to provide a self-adaptive humidity adjusting carton printing device and a carton printing process based on the device to solve the problems of poor printing quality, high waste rate and low automation in the existing carton printing, and the device and the process are deeply coupled, the device provides hardware support for the process, and the process realizes parameter adjustment through the device.

[0006] The present application achieves the above-mentioned purpose through the following technical scheme: a self-adaptive humidity adjusting carton printing device, comprising a front-end humidity detection module, a central control module, a printing execution adjustment module and a man-machine interaction module, each module is in communication connection with the central control module, and the whole is integrated on the machine body frame of the carton printing machine; The front-end humidity detection module is fixed at the front end of the paper feeding table of the printing machine, and is used for real-time acquisition of paperboard full-width humidity data and transmission to the central control module; The central control module is used for receiving the humidity data of the front-end humidity detection module and generating an adjustment instruction based on a preset "humidity-printing parameter" mapping algorithm, and simultaneously correcting the parameter deviation of the printing execution adjustment module through a closed-loop control logic. The core features of the mapping algorithm are: dividing at least three intervals according to the full-width average humidity of the paperboard, matching corresponding ink viscosity, plate- blanket pressure, drying temperature and paper feeding speed for each interval, and when the deviation of the humidity of each region from the average humidity exceeds a preset threshold, locally compensating the printing parameters of the deviation region; The printing execution adjustment module comprises: An automatic ink adjustment subsystem integrated in the ink tank of the printing machine for adjusting the ink viscosity; A pressure adjustment subsystem installed between the plate cylinder and the blanket cylinder of the printing machine for adjusting the cylinder contact pressure; An intelligent drying subsystem arranged in the drying channel at the paper receiving end of the printing machine for adjusting the drying temperature and air speed; A paper feeding speed adjustment subsystem adapted to the paper feeding motor of the printing machine for adjusting the paper feeding speed and eliminating static electricity; Each subsystem is in communication connection with the central control module, receives target parameter instructions and automatically executes adjustment; The human-machine interaction module is in communication with the central control module for process state monitoring, abnormal alarm and data storage; When working, the paperboard enters the paper feeding table from the paper stacking table, the front-end humidity detection module first collects full-width humidity data, the central control module generates target parameters based on the data, the printing execution adjustment module adjusts the printing parameters according to the instructions, and the human-machine interaction module synchronously monitors the state.

[0007] The application further provides that the front-end humidity detection module comprises 3 groups or more of humidity sensors uniformly distributed along the width direction of the paper feeding table, and the humidity sensor probe is vertically directed towards the paperboard surface; The humidity data of the paperboard are transmitted to the central control module in real time through the front-end humidity detection module.

[0008] The application further provides that the central control module comprises: A PLC main control unit for humidity data filtering, calibration and parameter matching logic operation; A parameter database unit pre-storing a "humidity-printing parameter" mapping algorithm, threshold parameters of local humidity compensation logic and response time parameters of closed-loop correction; A closed-loop control unit which is an eight-channel analog input module for collecting actual operating parameters of each system fed back by the printing execution adjustment module in real time, the analog channels of the closed-loop control unit being respectively connected with parameter detection sensor signals in different subsystems of the printing execution adjustment module for receiving analog signals output by the sensors.

[0009] The application further provides that the "humidity-printing parameter" mapping algorithm pre-stored in the parameter database unit is specifically: When the average moisture of the whole width of the paperboard is 7% to 8%, it is a low humidity interval, corresponding to ink viscosity 3000 mPa・s, plate-blanket pressure 10 kN / m, drying temperature 50℃, paper feeding speed 10000 sheets / hour; When the average moisture of the whole width of the paperboard is 9% to 11%, it is an optimal humidity interval, corresponding to ink viscosity 2800 mPa・s, plate-blanket pressure 9 kN / m, drying temperature 55℃, paper feeding speed 12000 sheets / hour; When the average moisture of the whole width of the paperboard is 12% to 13%, it is a high humidity interval, corresponding to ink viscosity 2500 mPa・s, plate-blanket pressure 8 kN / m, drying temperature 65℃, paper feeding speed 11000 sheets / hour; The humidity-printing parameter mapping algorithm supports manual updating through a touch screen of a man-machine interaction module or importing optimized parameters through a cloud interface.

[0010] The application is further provided that the automatic ink adjusting subsystem comprises: A micro-diluent pump is installed on the top of the ink tank of the printing machine and is communicated with the ink tank through a silica gel tube; A viscosity sensor is inserted into the ink tank, used for feeding ink viscosity data to the central control module in real time; To form a viscosity control closed loop of "detection-adjustment-feedback".

[0011] The application is further provided that the pressure adjusting subsystem comprises: A pneumatic pressure valve is installed on the bracket between the plate cylinder and the blanket cylinder, and is connected with the original air source of the printing machine through a pressure-resistant air pipe, and the pneumatic pressure valve is in communication connection with the central control module; A pressure sensor is fixed on the side of the cylinder bearing seat, used for detecting the contact pressure of the plate cylinder and the blanket cylinder in real time and feeding back to the central control module.

[0012] The application is further provided that the intelligent drying subsystem comprises: A plurality of electric heating pipes are evenly distributed along the top and both sides of the drying channel at the paper receiving end of the printing machine; Variable frequency blowers are symmetrically installed on both sides of the drying channel, used for adjusting the hot air speed; Temperature and humidity sensors are installed at the entrance and exit of the drying channel at the paper receiving end of the printing machine, used for feeding back environmental data to the central control module.

[0013] The application is further provided that the paper feeding speed adjusting subsystem comprises: A servo motor driver is adapted to the power of the paper feeding motor of the paper feeding system of the printing machine, and controls the rotating speed of the paper feeding motor through pulse signals; An electrostatic eliminator is arranged at the end of the paper feeding table to eliminate static electricity generated by low-humidity paperboard. An incremental encoder is arranged at the end of the paper feeding motor shaft through a shaft coupling to collect the actual rotating speed of the paper feeding motor in real time and feed back to the central control module. A pneumatic push plate is arranged on the side of the paper feeding table and is communicatively connected to the central control module, and is used to push the paperboard with humidity exceeding the standard to a waste collection groove.

[0014] The human-computer interaction module comprises: A touch screen is communicatively connected to the central control module and is used to display real-time humidity, current printing parameters and device running status. An alarm unit is an audible and visual alarm, which is automatically started when the paperboard humidity detected by the front-end humidity detection module is greater than 14% or less than 6%, and the paper feeding system is temporarily stopped through the central control module linkage. A data storage unit stores the humidity data, matched printing parameters, closed-loop correction records and waste rate data of each batch of paperboard in real time, and is configured with a cloud interface.

[0015] A paper box printing process of the above-mentioned self-adaptive humidity adjusting paper box printing device comprises the following steps: S1: The paperboard to be printed is conveyed to the printing operation area through the paper feeding table of the printing machine, before the paperboard enters the printing machine group, a plurality of humidity sensors of the front-end humidity detection module are started, the paperboard is scanned and detected along the width direction of the paperboard, the humidity data of each area of the paperboard is collected in real time, and the detection data is transmitted to the PLC main control unit of the central control module; S2: After the humidity detection data of S1 is received by the main control unit of the central control module, the data is preprocessed by filtering and calibration, the average humidity value of the whole width of the paperboard and the maximum humidity deviation value of each area are calculated, and the "humidity-printing parameter" mapping algorithm of the parameter database unit is called to match the parameters: If the maximum humidity deviation value is less than or equal to ±0.5%, the target printing parameter corresponding to the average humidity value is directly matched; If the maximum humidity deviation value is greater than ±0.5%, the local humidity compensation logic is called, the paperboard width is divided into a plurality of detection areas according to the humidity sensor arrangement, and the partition target printing parameters are matched according to the humidity difference of each area, which are as follows: If the difference between the humidity value of a detection area and the average humidity value of the whole width of the paperboard is greater than or equal to 0.8%, the central control module sends an instruction to the intelligent drying subsystem corresponding to the area, the drying temperature is increased by 5-8℃, an instruction is sent to the pressure adjusting subsystem, the plate-blanket pressure is reduced by 0.5-1kN / m, the ink viscosity remains unchanged, and the paper feeding speed remains unchanged; If the difference between the humidity value of a certain detection area and the average humidity value of the whole paperboard width is ≤-0.8%, the drying temperature remains unchanged, the plate-blanket pressure remains unchanged, the central control module sends instructions to the automatic ink adjustment subsystem, the ink viscosity is increased by 100-200 mPa·s, and the paper feeding speed is reduced by 500-800 sheets / hour; If the difference between the humidity value of a certain detection area and the average humidity value of the whole paperboard width is within ±0.8%, the drying temperature, the plate-blanket pressure, the ink viscosity, and the paper feeding speed all remain unchanged; S3: The central control module sends the target parameter instructions matched in S2 to the printing execution adjustment module, and each subsystem synchronously executes the adjustment: S3a: Start the micro-diluent pump of the automatic ink adjustment subsystem to inject diluent into the ink tank, and the actual viscosity of the ink is collected in real time by the viscosity sensor and fed back to the central control module until the actual viscosity reaches the target value; S3b: Adjust the contact pressure between the plate cylinder and the blanket cylinder through the pneumatic pressure valve of the pressure adjustment subsystem, and the actual pressure is fed back in real time by the pressure sensor until the pressure reaches the target value; S3c: Control the temperature rise of the electric heating pipe and the speed of the variable frequency fan of the intelligent drying subsystem, and the actual temperature and humidity data of the inlet and outlet of the drying channel are monitored in real time by the temperature and humidity sensor until the temperature of the drying channel reaches the target drying temperature; S3d: Adjust the paper feeding speed through the servo driver of the paper feeding speed adjustment subsystem, and the motor speed is fed back by the encoder until the paper feeding speed reaches the target paper feeding speed value, and if the paperboard humidity is <8%, the electrostatic eliminator (11) is started to eliminate the static electricity of the paperboard; S4: During the printing process, the central control module continuously collects the ink viscosity, cylinder pressure, drying temperature, and paper feeding speed fed back by the printing execution adjustment module, and compares the deviation with the target parameters: If the deviation is ≤3%, the current parameters are maintained; If the deviation is >3%, a correction instruction is generated within 0.5 seconds, and the correction instruction is as follows: If the ink viscosity deviation is >±3%, adjust the diluent pump flow, and for every 1% of the deviation, the flow is ±2%; If the cylinder pressure deviation is >±3%, adjust the output of the pneumatic pressure valve, and for every 1% of the deviation, the pressure is ±1%; If the drying temperature deviation is >±3℃, adjust the heating pipe power, and for every 1℃ of the deviation, the power is ±3% or the fan speed is ±5%; If the paper feeding speed deviation is >±1%, adjust the frequency of the servo driver, and for every 0.5% of the deviation, the frequency is ±0.3 Hz; The correction response time is ≤0.5 seconds until the deviation is ≤3%; S5: If S1 detects that the paperboard humidity is >14% or <6%, the central control module triggers an alarm, controls the paper feeding system to pause, and pushes the paperboard exceeding the standard to the waste slot through the pneumatic push plate. After the paperboard exceeding the standard is removed, the front-end humidity detection module rechecks the subsequent paperboard, and restores the paper feeding after confirming that the humidity is 8-12%.

[0016] Compared with the prior art, the beneficial effects of the present application are: Firstly, through full-width scanning by 3 groups or more sensors, ±0.5% humidity difference triggers zoned compensation, avoiding problems such as image smearing in high-humidity areas, ink layer falling off in low-humidity areas, and paperboard brittle cracking, the full-width printing consistency deviation is ≤2%, and through the closed-loop correction mechanism, the ink viscosity, cylinder pressure, drying temperature, and paper feeding speed are accurately landed, and the ink layer adhesion rate meets the standard, at the same time, through automatic removal when the humidity is >14% or <6%, recheck and resume production, prevent the paperboard exceeding the standard from flowing into the printing link, so that the printing quality is significantly improved, and the defect rate is greatly reduced. Secondly, from humidity detection, parameter matching, zoned adjustment to closed-loop correction, manual adjustment of printing parameters is not required, reducing manual intervention time, adapting to high-speed production lines, and through automatic alarm + removal + recheck and recovery of abnormal processing, overall shutdown is not required, reducing downtime. Thirdly, the process adapts to existing carton printing machines, relies on special device integration, avoids overall equipment replacement or large-scale modification, and reduces production costs, and combined with zoned compensation, closed-loop correction, and abnormal removal, the comprehensive scrap rate is reduced from 3%~5% of the traditional process to 0.5%~1%, greatly reducing paperboard, ink, and other resource waste. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 Structure diagram of the self-adaptive humidity adjusting carton printing device; Figure 2 Structure diagram of the pressure regulating subsystem; Figure 3 Structure diagram of the paper feeding speed regulating subsystem; Figure 4 Process flow chart of the present application.

[0018] Mark: 1, humidity sensor; 2, micro-diluent pump; 3, viscosity sensor; 4, pressure regulating subsystem; 5, pneumatic pressure valve; 6, pressure sensor; 7, electric heating tube; 8, variable frequency fan; 9, temperature and humidity sensor; 10, servo motor driver; 11, static eliminator; 12, incremental encoder; 13, pneumatic push plate. DETAILED DESCRIPTION

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. In this description, it should be understood that the terms "upper," "lower," "front," "rear," "left," "right," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Example

[0020] Adaptive humidity control carton printing equipment, such as Figures 1-3 As shown, the machine frame is integrated into the existing carton printing machine without modifying the main structure of the printing machine. It includes a front-end humidity detection module, a central control module, a printing execution adjustment module, and a human-machine interaction module. Each module is connected to the central control module via a Belden 3071F shielded cable. Through the coordinated operation of each module, a complete workflow of "data acquisition → data processing → parameter execution → closed-loop correction → status monitoring → anomaly handling" is formed, realizing the adaptive matching of "humidity-printing parameters" during the carton printing process, and ultimately ensuring stable printing quality under different humidity conditions.

[0021] The front-end humidity detection module serves as the data source for the process humidity. Fixed at the front of the printing press's paper feed table, it ensures data accuracy by activating detection when the cardboard is transported individually from the stacking table to the feed table, just as it is detached from the stacking constraints and its humidity is unaffected by the printing environment. Consequently, as the cardboard exits the stacking table, real-time humidity data across the entire cardboard surface is collected and transmitted to the central control module.

[0022] The front-end humidity detection module includes three or more humidity sensors 1 evenly distributed along the width of the paper feed table, avoiding the error of "local humidity representing the whole area" caused by single-point detection. The humidity sensor 1 uses an NDCCM710e multi-wavelength infrared moisture sensor with a detection accuracy of ±0.1% and a detection range of 0.1% to 40%. It can penetrate the surface of the cardboard to detect internal humidity, avoiding interference from surface dust and color. Furthermore, the probe of the humidity sensor 1 is perpendicular to the cardboard surface, with a spacing controlled between 28mm and 32mm to ensure unobstructed detection. It is also equipped with a dustproof and waterproof housing to enclose the humidity sensor 1. This housing is made of IP65-grade stainless steel and has a built-in air-cooling structure, adapting to the high dust and ink evaporation environment of the printing workshop and ensuring the effective use of the humidity sensor 1.

[0023] The collected full-width humidity data, including humidity values of left, middle and right areas, are transmitted to the central control module through the RS485 bus at a transmission rate of 115200bps and a delay of <0.1s, which can match a high-speed printing production line of 12000 sheets / hour, ensuring synchronization of data transmission and paper conveying rhythm without lag.

[0024] The central control module is the core of the device and process, installed in the electrical control cabinet on the operation side of the printing machine. It generates adjustment instructions based on the preset "humidity-printing parameter" mapping algorithm by receiving humidity data from the front-end humidity detection module, and corrects the parameter deviation of the printing execution adjustment module through closed-loop control logic.

[0025] The core feature of the mapping algorithm is to divide the average humidity of the full-width paperboard into at least three intervals, match the corresponding ink viscosity, plate-blanket pressure, drying temperature and paper feeding speed for each interval, and perform local compensation on the printing parameters of the deviation area when the humidity deviation of each area exceeds the preset threshold.

[0026] The core feature of the closed-loop control logic is to collect the actual parameters of the printing execution adjustment module in real time at a preset frequency, calculate the deviation from the target parameters, and generate correction instructions within a limited time when the deviation exceeds the preset threshold until the deviation falls within the threshold.

[0027] The humidity interval division rule, the parameter type corresponding to each interval, the deviation threshold of local compensation, the closed-loop sampling frequency, the deviation threshold and the correction time are all pre-stored in the parameter database unit of the central control module, and are adapted to the sensor accuracy of the front-end humidity detection module and the execution accuracy of the printing execution adjustment module.

[0028] The central control module includes a PLC main control unit, a parameter database unit and a closed-loop control unit. The PLC main control unit uses Siemens S7-1214C with an operation speed of 0.1μs / instruction, which can process 3 groups of sensor data and 4-way execution module instructions simultaneously, realizing humidity data filtering, calibration and parameter matching logic operation.

[0029] The parameter database unit uses an 8GB embedded storage chip to pre-store the "humidity-printing parameter" mapping algorithm and local humidity compensation logic parameters, supports manual update through the human-computer interaction module or import of optimized parameters through the cloud interface, and its optimized parameters need to follow the core logic of 'paperboard humidity interval division + ink viscosity / pressure / temperature / speed linkage matching', mainly playing the role of algorithm storage and invocation.

[0030] The closed-loop control unit adopts a Siemens SM1231 eight-channel analog input module. The eight-channel analog input module receives the "parameter signals" output by the sensors of each subsystem of the printing execution adjustment module and provides an adaptive signal interface for different types of sensors for real-time collection of the actual operating parameters of each system fed back by the printing execution adjustment module.

[0031] The sampling frequency of the analog input module for parameters such as viscosity, pressure, and temperature is set to 10 Hz, i.e., 10 samples per second, which is much higher than the parameter change speed of the printing machine. For example, the ink viscosity change period is ≥1 second, and the temperature change period is ≥5 seconds, ensuring that small fluctuations in parameters can be captured, such as a change of ±50 mPa・s in viscosity; The pulse signal sampling frequency of the encoder is set to 100 kHz, which can accurately capture the speed change of the paper feed motor, such as a speed fluctuation of ±10 revolutions / minute, and the converted paper feed speed error is ≤50 sheets / hour, meeting the requirement of speed regulation accuracy ±100 sheets / hour.

[0032] Each analog channel corresponds to one sensor, and the channels are independent of each other. For example, channel one is connected to the viscosity sensor 3, and channel two is connected to the pressure sensor 6, avoiding signal crosstalk. All sensor cables use twisted shielded cables, with the shielding layer single-ended grounded, and the grounding resistance ≤4Ω, avoiding electromagnetic interference generated by the workshop motor and frequency converter. The analog module and the central control module are installed in a metal electric control cabinet, and the cabinet body is grounded, further shielding external interference.

[0033] The central control module processes the collected raw data with "sliding average filtering", such as taking the average of the last 5 sampling values as the final data, removing accidental signal spikes, such as false data caused by instantaneous current fluctuations, to ensure data authenticity.

[0034] The working logic of the central control module is to receive front-end data → Kalman filter to remove interference → temperature compensation calibration → calculate the full-width average humidity + maximum deviation of each area, where the humidity deviation is calculated as: Humidity deviation = (Actual humidity parameter - Target humidity parameter) / Target humidity parameter × 100%.

[0035] Meanwhile, the specific parameter matching of the central control module is as follows: When the humidity deviation ≤±0.5%, the "humidity-printing parameter" mapping algorithm is called to generate the global target parameter: When the full-width average humidity of the paperboard is between 7% and 8%, it is in the low humidity range, corresponding to an ink viscosity of 3000 mPa・s, a plate-blanket pressure of 10 kN / m, a drying temperature of 50℃, and a paper feed speed of 10000 sheets / hour; When the average humidity of the full width of the paperboard is 9% to 11%, it is the optimal humidity interval, corresponding to ink viscosity 2800 mPa·s, plate-blanket pressure 9 kN / m, drying temperature 55℃, paper feeding speed 12000 sheets / hour; When the average humidity of the full width of the paperboard is 12% to 13%, it is the high humidity interval, corresponding to ink viscosity 2500 mPa·s, plate-blanket pressure 8 kN / m, drying temperature 65℃, paper feeding speed 11000 sheets / hour; Among them, the low humidity interval sets the ink viscosity to 3000 mPa·s, and the core basis is as follows: Paperboard characteristics: low humidity paperboard has a dense fiber structure, weak ink absorption, and easy static on the surface. If the ink viscosity is too low, such as <2800 mPa·s, it will cause 'ink floating' and 'ink smearing' due to the too strong flowability of the ink layer, and the adhesion between the ink layer and the paperboard fiber is insufficient, which is prone to falling off later; Ink rheological property: under low humidity environment, the solvent evaporation speed of the ink is accelerated, and the viscosity is easily increased. The setting of 3000 mPa·s not only reserves the viscosity redundancy of solvent evaporation, but also can maintain dynamic balance through the fine adjustment of the micro diluent pump, to ensure the uniformity of ink transfer on the plate cylinder; Printing quality matching: the thixotropy of the ink corresponding to this viscosity value can adapt to the paper feeding speed of 10000 sheets / hour. The ink flows and spreads under the action of pressure during printing, and quickly restores the viscosity after shutdown to avoid ink drop pollution, while ensuring the edge definition of the image and text.

[0036] Among them, the "humidity-printing parameter" mapping algorithm supports manual update through the touch screen of the human-computer interaction module or import of optimized parameters through the cloud interface; When the humidity deviation is >±0.5%: trigger local humidity compensation logic: High humidity area: temperature +5~8℃, pressure -0.5~1 kN / m; Low humidity area: viscosity +100~200 mPa·s, speed -500~800 sheets / hour); Generate partition target parameters; Closed loop correction: collect actual printing parameters every 0.1 seconds → calculate deviation, wherein the printing parameter deviation is calculated as: printing parameter deviation=(actual printing execution value parameter-target printing execution value parameter) / target printing execution value parameter×100%→ when the printing parameter deviation is >3%(paper feeding speed is >1%), generate correction instructions within 0.5 seconds→ until the printing parameter deviation is ≤3%.

[0037] Among them, ±0.5% is selected as the local humidity compensation trigger threshold, which is based on the following technical balance: Quality sensitivity threshold: experimental verification shows that when the humidity difference of different regions of the same paperboard is less than or equal to 0.5%, the local difference of the ink absorption and stiffness of the paperboard can be offset by the natural diffusion of the ink, and the full-width consistency deviation of the printed paperboard is less than or equal to 0.3%; if the difference is greater than 0.5%, obvious defects such as ink accumulation in the high-humidity area and ink floating in the low-humidity area will occur; Sensor precision support: the detection precision of the front-end humidity sensor 1 is ±0.1%, which is much higher than the threshold requirement of ±0.5%, and can accurately identify the real humidity difference and avoid false triggering caused by sensor errors; Execution stability balance: if the threshold is set too small, such as ±0.3%, the execution components, such as pumps, valves, and motors, will be frequently started and stopped for adjustment, which will shorten the service life of the components and cause parameter fluctuations; if the threshold is too large, such as ±0.8%, it will miss the quality problems caused by slight humidity unevenness, therefore, ±0.5% is the optimal balance point of 'quality sensitivity' and 'execution stability'.

[0038] The printing execution adjustment module is a parameter execution layer, which is embedded in the ink system, pressure system, drying system, and paper feeding system of the printing machine, and includes four subsystems, namely, an automatic ink adjustment subsystem, a pressure adjustment subsystem 4, an intelligent drying subsystem, and a paper feeding speed adjustment subsystem, which receive target parameter instructions from the central control module, and adjust the ink viscosity, cylinder pressure, drying temperature and humidity, and paper feeding speed through the four subsystems to realize accurate landing of parameters.

[0039] The automatic ink adjustment subsystem is composed of a 304 stainless steel, a micro-diluent pump 2 with a model of IWAKIEW-60, and a viscosity sensor 3 with a model of Anton Paar SVM3000. The flow adjustment range of the diluent pump is 0.1L / h-1L / h, which is installed on the top of the ink tank of the printing machine and connected to the ink tank through a 6mm inner diameter silica gel pipe. The precision of the viscosity sensor 3 is ±5mPa・s, and the probe is inserted into the ink tank to a depth of 50mm. The viscosity sensor 3 outputs corresponding current signals according to the ink viscosity, and the conversion logic between the ink viscosity and the corresponding current signal is: (viscosity value / 5000mPa・s) x 16mA + 4mA, for example, 2500mPa・s corresponds to 12mA, and 3000mPa・s corresponds to 14.4mA.

[0040] The current signal is transmitted to channel one of the analog module through an ink-resistant shielding cable, and the AD converter in the analog module converts the current signal into a digital value. Under 12-bit precision, 4-20mA corresponds to a digital value of 0-27648, and 12mA corresponds to a digital value of 13824. The digital value is transmitted to the PLC main control unit through the Profinet bus.

[0041] Execution logic: the central control module issues viscosity target value → viscosity sensor 3 real-time detection → generate 4-20 mA signal according to (viscosity value / 5000 mPa·s) x 16 mA + 4 mA → transmission to closed-loop control unit channel one → analog module converts the signal to a digital value (12-bit precision, 4-20 mA corresponds to 0-27648) → the central control module converts the digital value to current value and then to viscosity value → compares the target value to adjust the diluent pump injection volume → forms a "detection-adjustment-feedback" closed loop, the response time of the closed loop is ≤0.5 seconds, and the viscosity deviation is ≤3%.

[0042] As shown in Figure 2 The pressure regulating subsystem 4 is configured with one set of pneumatic pressure valve 5 of model Festo VPPM-6L-L-1-G18-0L6H-A4P and pressure sensor 6 of model HBMU9C between the plate cylinder and blanket cylinder of each process color printing. The output range of the pneumatic pressure valve 5 is 0-0.8 MPa, and the accuracy is ±0.01 MPa. It is connected to the original air source of the printing machine through a pressure-resistant air pipe and is in communication connection with the central control module. It is installed on the bracket between the plate and blanket cylinders. The pressure sensor 6 has a range of 0-20 kN / m and an accuracy of ±0.1 kN / m. It is fixed to the side of the cylinder bearing seat and detects the contact pressure between the cylinders in real time through a pressure strain gauge.

[0043] The pressure sensor 6 outputs a current signal according to the actual pressure. The pressure conversion logic is (pressure value / 20 kN / m) x 16 mA + 4 mA. For example, 8 kN / m corresponds to 8.8 mA, and 10 kN / m corresponds to 12 mA. The signal is transmitted to channel two of the analog module through a shielded cable. Each set of process color cylinder corresponds to one channel. For example, a four-color printing machine needs four channels. Here, a single channel is taken as an example. The analog module converts the current signal to a digital value. For example, 8.8 mA corresponds to a digital value of 12205. After transmission to the central control module, the actual pressure is converted.

[0044] Execution logic: the central control module issues pressure target value → pressure sensor 6 detects actual pressure through strain gauge → generate 4-20 mA signal according to (pressure value / 20 kN / m) x 16 mA + 4 mA → transmission to closed-loop control unit channel two → analog module converts to digital value → central control module converts actual pressure → compares target value to adjust pneumatic pressure valve 5 output → dynamically corrects cylinder contact pressure.

[0045] The intelligent drying subsystem includes an electric heating tube 7 of SINCO HT-1000, a variable frequency fan 8 of EBMPAP STR2E133-AA44-30, and a temperature and humidity sensor 9 of Sensirion SHT31, wherein the electric heating tube 7 has a power of 1 kW, is arranged along the top and both sides of the drying channel at the paper receiving end in 6 groups, and is externally provided with a stainless steel protective net with a hole diameter of 10 mm for protection.

[0046] The variable frequency fan 8 is symmetrically installed on both sides of the drying channel, and the air volume adjustment range is 500 m³ / h-1500 m³ / h. It is used to adjust the hot air speed. Meanwhile, one group of temperature and humidity sensors 9 are installed at the entrance and exit of the drying channel at the paper receiving end, which has a temperature accuracy of ±1℃ and a humidity accuracy of ±2%RH, and can real-time control the drying temperature.

[0047] The temperature sensor detects the actual temperature in the drying channel and outputs a corresponding current signal. The temperature conversion logic is: current signal (mA) = (temperature value T + 40℃) / 165℃×16mA+4mA.

[0048] Deduction basis: The temperature range of the temperature and humidity sensor 9 (Sensirion SHT31) is -40℃-125℃, and the range span is =125-(-40)=165℃. The 4-20mA signal corresponds to the range, i.e. -40℃ corresponds to 4mA and 125℃ corresponds to 20mA. Therefore, the current signal of the intermediate temperature T is "(T-(-40)) / 165×(20-4)+4", which is simplified to the above formula.

[0049] Execution logic: the central control module issues a drying temperature target value → the temperature and humidity sensor 9 detects the actual temperature → generates a 4-20mA signal according to (temperature value + 40℃) / 165℃×16mA+4mA → transmits to the closed-loop control unit channel three → the central control module converts the actual temperature and compares the inlet / outlet temperature difference (normal ≤3℃) → adjusts the power of the electric heating tube 7 (deviation of each 1℃±3%) or the fan speed (deviation of each 1℃±5%) → ensures uniform drying.

[0050] As shown in Figure 3 , the paper feeding speed regulating subsystem includes a servo motor driver 10 of Schneider LXM32AD18M2, an ion air nozzle type static eliminator 11 of Simco-Ion Top Gun, and an incremental encoder 12 of Baigefu RVI58N.

[0051] Where servo motor driver 10, adaptive paper feeding motor 5.5kW power, through the pulse signal control, speed accuracy ±100 sheets / hour. Ion wind nozzle type static eliminator 11 installed at the end of the paper feeding table, its length is 500mm, 100mm away from the paperboard surface, output voltage 5kV, eliminating low humidity paperboard static. Incremental encoder 12 installed at the end of the paper feeding motor shaft, through the pulse number to calculate the motor speed, and then convert the paper feeding speed, its speed detection accuracy ±10 revolutions / minute.

[0052] Execution logic: the central control module sends the paper feeding speed target value→converts it into the motor speed target value→the servo driver controls the motor speed through the pulse + direction signal (pulse equivalent 1000 pulses / revolution)→the encoder outputs A / B phase pulse signal (1000 revolutions / minute corresponds to 17067Hz)→transmitted to the high-speed counter interface of the PLC main control unit→the central control module converts according to "pulse frequency→motor speed→paper feeding speed"→adjusts the driver frequency compared to the target value; when the humidity is less than 8%, the static eliminator 11 is started synchronously.

[0053] The human-computer interaction module plays the role of state monitoring + data storage layer, which includes touch screen, sound and light alarm unit, data storage unit, among which the touch screen adopts 7-inch Wintek TK6071iQ color touch screen with a resolution of 800×480, which displays real-time humidity, target parameters, actual parameters and device running status, supports manual parameter modification and algorithm update.

[0054] The sound and light alarm unit adopts a buzzer with a decibel≥85dB and a red LED lamp with a diameter of 20mm, which is automatically started when the paperboard humidity is greater than 14% or less than 6%, and at the same time, the paper feeding system is paused.

[0055] The data storage unit adopts Kingston Industrial 32GB SD card, which stores the corresponding data of "humidity data-target parameters-correction records-waste rate" within 3 months, supports exporting Excel format report through Ethernet interface, or uploading to cloud platform through Aliyun interface.

[0056] Working logic State display: the central control module pushes data to the touch screen in real time, which visualizes the full-width humidity distribution, target / actual parameters and device running status; Data storage: each batch of data is automatically stored, which supports exporting Excel report through Ethernet interface (TCP / IP protocol) or accessing Aliyun IoT platform through MQTT protocol.

[0057] The paper feeding speed control subsystem also includes a FestoDGSL-25-50-PA cylinder with a guide rod installed on the side of the paper feeding table and a pneumatic pusher plate 13 installed at the output end. The cylinder with the guide rod is connected to the central control module. When the front-end humidity detection module detects that the paperboard humidity is >14% or <6%, the human-machine interface module links the paper feeding system to pause. At the same time, the cylinder with the guide rod is activated to push the pneumatic pusher plate 13 to move in the vertical paper feeding direction, pushing the paperboard with excessive humidity to the waste collection trough. After the pneumatic pusher plate 13 is reset, the front-end humidity detection module re-inspects the first paperboard. If the humidity of the re-inspection is 8% to 12%, which is within the acceptable range, the central control module controls the paper feeding system to resume operation. If the re-inspection still exceeds the standard, the "alarm-rejection" step is repeated until a qualified paperboard is detected.

[0058] All module wiring uses Belden 3071F twisted-pair shielded cable, which is resistant to ink and temperature from -20℃ to 80℃, and is grounded. The cable shield is grounded at one end (grounding resistance ≤ 4Ω), and the metal control cabinet is grounded to avoid electromagnetic interference.

[0059] A carton printing process for the above-mentioned adaptive humidity-controlled carton printing apparatus, such as Figure 4 As shown, it includes the following steps: S1: The cardboard to be printed is conveyed to the printing operation area through the paper feeding table of the printing press. Before the cardboard enters the printing press unit, three or more NDCCM710e humidity sensors are activated to scan and detect along the width direction at a frequency of 10 times / second, and transmit the humidity data of each area to the PLC main control unit through the RS485 bus. S2: After receiving the humidity detection data from S1, the central control module main control unit first filters and calibrates the data, and calculates the average humidity value of the entire paperboard surface and the maximum humidity deviation value of each area. Then, the "humidity-printing parameter" mapping algorithm in the parameter database cell is called to match the parameters: If the maximum humidity deviation is ≤ ±0.5%, directly match the target printing parameters corresponding to the average humidity value; If the maximum humidity deviation is > ±0.5%, the local humidity compensation logic is invoked. The width of the cardboard is divided into multiple detection areas according to the layout of humidity sensor 1. The target printing parameters for each area are matched separately for the humidity difference. Specifically: If the difference between the humidity value of a certain detection area and the average humidity value of the entire paperboard is ≥0.8%, the central control module sends an instruction to the intelligent drying subsystem corresponding to that area to increase the drying temperature by 5-8℃. At the same time, it sends an instruction to the pressure regulation subsystem 4 to reduce the printing plate-rubber blanket pressure by 0.5-1kN / m, while keeping the ink viscosity and paper feeding speed unchanged. If the difference between the humidity value of a certain detection area and the average humidity value of the whole paperboard width is ≤-0.8%, the drying temperature remains unchanged, the plate-blanket pressure remains unchanged, the central control module sends instructions to the automatic ink adjusting subsystem, the ink viscosity is increased by 100-200 mPa·s, and the central control module sends instructions to the paper feeding speed adjusting subsystem, the paper feeding speed is reduced by 500-800 sheets / hour; If the difference between the humidity value of a certain detection area and the average humidity value of the whole paperboard width is within ±0.8%, the drying temperature, the plate-blanket pressure, the ink viscosity, and the paper feeding speed all remain unchanged; S3: The central control module sends the target parameter instructions matched in S2 to the printing execution adjustment module, and each subsystem synchronously executes the adjustment: S3a: Start the micro-diluent pump 2 of the automatic ink adjusting subsystem to inject diluent into the ink tank, the actual viscosity of the ink is collected in real time by the viscosity sensor 3, and the feedback is fed back to the central control module until the actual viscosity deviation from the target value is ≤3%; S3b: Adjust the contact pressure between the plate cylinder and the blanket cylinder through the pneumatic pressure valve 5 of the pressure adjusting subsystem 4, and the actual pressure is fed back in real time by the pressure sensor 6 until the pressure deviation is ≤±0.1 kN / m; S3c: Control the temperature of the electric heating pipe 7 of the intelligent drying subsystem and the speed of the variable frequency fan 8, and monitor the actual temperature and humidity data of the inlet and outlet of the drying channel in real time by the temperature and humidity sensor 9 until the temperature uniformity deviation of the drying channel is ≤±2℃; S3d: Adjust the paper feeding speed through the servo driver of the paper feeding speed adjusting subsystem, and feed back the motor speed through the encoder until the paper feeding speed deviation is ≤±1%, and if the paperboard humidity is <8%, simultaneously start the electrostatic eliminator 11 to eliminate the static electricity of the paperboard; S4: During the printing process, the central control module continuously collects the ink viscosity, cylinder pressure, drying temperature, and paper feeding speed fed back by the printing execution adjustment module, and compares the deviation with the target parameters, wherein the actual parameters of viscosity, pressure, temperature, and speed are collected every 0.1 second, the deviation is calculated as deviation=(actual value-target value) / target value×100%, and the correction logic is as follows: If the deviation is ≤3%, the current parameters are maintained; If the deviation is >3%, a correction instruction is generated within 0.5 seconds, and the correction instruction is as follows: If the ink viscosity deviation is >±3%, adjust the diluent pump flow, and the flow is ±2% for every 1% of the deviation; If the cylinder pressure deviation is >±3%, adjust the output of the pneumatic pressure valve 5, and the pressure is ±1% for every 1% of the deviation; If the drying temperature deviation is >±3℃, adjust the heating pipe power, and the power is ±3% or the fan speed is ±5% for every 1℃ of the deviation; Paper feed speed deviation > ±1%: Adjust the servo drive frequency; for every 0.5% deviation, adjust the frequency by ±0.3Hz. Correct the response time to ≤0.5 seconds until the deviation is ≤3%. If the deviation still fails to meet the standard after 5 consecutive corrections, trigger the parameter abnormality alarm, suspend printing, and manually check for problems such as sensor failure and execution component jamming. After resetting the alarm through the human-machine interaction module, production can be resumed to avoid the mass production of unqualified products. S5: If S1 detects that the paperboard humidity is >14% or <6%, the central control module triggers an alarm and simultaneously controls the paper feeding system to pause. The paper feeding system restarts within 0.2 seconds after the pause and uses the pneumatic pusher 13 to push the paperboard in the vertical feeding direction. The stroke is 50~100mm and the action time is 0.3 seconds. This pushes the paperboard that exceeds the standard to the waste bin. After the paperboard that exceeds the standard is rejected, it immediately resets after the push is completed and waits for the re-inspection instruction. The front-end humidity detection module re-inspects the subsequent paperboard. After confirming that the humidity is 8-12%, the paper feeding resumes. If the re-inspection fails, the "alarm-rejection" continues until the inspection is qualified.

[0060] In S2, the filtering is: Kalman filtering + moving average filtering (averaging of 5 consecutive sample values) to remove false data; the calibration is: for every 5°C deviation in ambient temperature, the humidity value is corrected by ±0.05%; the analysis is: removing out-of-range data (0.1%~40%), and calculating the average humidity value of the entire area + the maximum humidity deviation value of each area.

[0061] The difference between the humidity value of the detection area in S2 and the average humidity value of the entire paperboard surface is selected as ±0.8% as the zoning adjustment threshold, based on the following: When the difference between the regional humidity and the average humidity is ≤ ±0.8%, the printing consistency requirement can be met through the natural adaptation of global parameters, i.e., the deviation is ≤ 0.5%. If the difference is > ±0.8%, the local ink absorption difference cannot be offset, and the parameters need to be adjusted accordingly. Therefore, this threshold is the optimal balance between 'compensation effect' and 'execution efficiency'.

[0062] The definitions and coordination logic for the synchronous execution of adjustments by each subsystem in S3 are as follows: Synchronization standard: After the central control module issues the target parameter command, each subsystem must start the adjustment action within 0.3 seconds, and the time difference between the adjustment completion of all subsystems shall be ≤0.2 seconds to ensure the compatibility of parameters such as ink viscosity, roller pressure, drying temperature and paper feeding speed; Priority settings: sorted by 'criticality to printing quality', with the following priority: automatic ink adjustment subsystem (viscosity) > pressure regulation subsystem (pressure) > intelligent drying subsystem (temperature) > paper feed speed control subsystem (speed); after the preceding priority subsystems are adjusted to meet the standards (deviation ≤3%), the subsequent subsystems will complete the final calibration to avoid parameter superposition deviations; Feedback linkage: each subsystem adjusts the progress in real time through sensors, if a certain subsystem adjustment timeout (more than 1 second not up to standard), the central control module suspends the adjustment action of other subsystems, and restarts the synchronization process after the subsystem meets the standard; Response speed adaptation: according to the hardware characteristics of different subsystems, preset response compensation: the response time of the micro-diluent pump in the automatic ink adjustment subsystem is 0.1 seconds, the response time of the pneumatic pressure valve in the pressure adjustment subsystem is 0.08 seconds, the temperature rise delay of the electric heating pipe in the intelligent drying subsystem is 0.2 seconds and the startup is 0.1 seconds in advance, the response time of the servo driver in the paper feeding speed regulation subsystem is 0.05 seconds, and the dynamic synchronization is realized through time compensation.

[0063] Among them, the alarm priority in S5 is: parameter abnormality alarm> humidity exceeds the standard alarm; when triggered at the same time, the'suspend production' action of the parameter abnormality alarm is executed first, and after the troubleshooting is completed, the humidity exceeds the standard problem is processed. After the alarm is removed, the central control module automatically recovers to the target printing parameter before the alarm, without the need to re-match, ensuring the continuity of production.

[0064] It is apparent to those skilled in the art that the present application is not limited to the details of the foregoing exemplary embodiments, and that the present application can be implemented in other specific forms without departing from the spirit or essential characteristics of the present application. Therefore, the embodiments should be considered in all respects as illustrative and not restrictive, and the scope of the present application is defined by the appended claims rather than the foregoing description, and it is intended to encompass all changes falling within the meaning and range of equivalents of the elements of the claims. Any reference signs in the claims should not be considered as limiting the claims to which they belong.

[0065] In addition, it should be understood that although the present specification is described in terms of embodiments, not every embodiment contains only one independent technical solution, and the description of the specification is only for the sake of clarity, and those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can be properly combined to form other embodiments that those skilled in the art can understand.

Claims

1. An adaptive humidity-controlled carton printing device, characterized in that: It includes a front-end humidity detection module, a central control module, a printing execution adjustment module, and a human-machine interaction module. Each module is connected to the central control module and is integrated into the machine frame of the carton printing machine. The front-end humidity detection module is fixed to the front end of the paper feeding table of the printing press and is used to collect the humidity data of the entire paperboard in real time and transmit it to the central control module. The central control module is used to receive humidity data from the front-end humidity detection module and generate adjustment instructions based on the preset "humidity-printing parameter" mapping algorithm. At the same time, it corrects the parameter deviation of the printing execution adjustment module through closed-loop control logic. The core feature of the mapping algorithm is: dividing the paperboard into at least three intervals based on the average humidity of the entire surface, matching the corresponding ink viscosity, printing plate-rubber blanket pressure, drying temperature and paper feeding speed for each interval, and when the deviation of the humidity of each area from the average humidity exceeds a preset threshold, the printing parameters of the deviation area are locally compensated. The printing execution adjustment module includes: An automatic ink adjustment subsystem, integrated into the ink tank of a printing press, is used to adjust the viscosity of the ink; The pressure regulation subsystem (4) is installed between the printing plate cylinder and the blanket cylinder of the printing press and is used to adjust the cylinder contact pressure. The intelligent drying subsystem is installed in the drying channel at the paper delivery end of the printing press to adjust the drying temperature and airflow. The paper feed speed control subsystem is adapted to the paper feed motor of the printing press and is used to adjust the paper feed speed and eliminate static electricity. Each subsystem is connected to the central control module to receive target parameter instructions and automatically perform adjustments; The human-machine interaction module communicates with the central control module and is used for process status monitoring, abnormal alarms, and data storage. During operation, the cardboard enters the paper feeding table from the stacking table. The front-end humidity detection module first collects full-width humidity data, the central control module generates target parameters based on the data, the printing execution adjustment module adjusts the printing parameters according to the instructions, and the human-machine interaction module monitors the status synchronously.

2. The adaptive humidity-controlled carton printing device according to claim 1, characterized in that: The front-end humidity detection module includes three or more humidity sensors (1) evenly distributed along the width of the paper feed table, with the probes of the humidity sensors (1) facing the paperboard surface vertically. The humidity data of the cardboard is collected in real time and transmitted to the central control module through the front-end humidity detection module.

3. The adaptive humidity-controlled carton printing device according to claim 1, characterized in that: The central control module includes: The PLC main control unit is used for filtering, calibration, and parameter matching logic operations of humidity data. The parameter database unit pre-stores the "humidity-printing parameter" mapping algorithm, the threshold parameters of the local humidity compensation logic, and the response time parameters of the closed-loop correction. The closed-loop control unit is an eight-channel analog input module used to collect the actual operating parameters of each system fed back by the printing execution adjustment module in real time. The analog channels of the closed-loop control unit are respectively connected to the parameter detection sensor signals in different subsystems of the printing execution adjustment module to receive the analog signals output by the sensors.

4. The adaptive humidity-controlled carton printing device according to claim 3, characterized in that: The "humidity-printing parameter" mapping algorithm pre-stored in the parameter database unit is as follows: When the average humidity of the entire paperboard surface is between 7% and 8%, it is considered a low humidity range, corresponding to an ink viscosity of 3000 mPa·s, a printing plate-rubber blanket pressure of 10 kN / m, a drying temperature of 50℃, and a paper feeding speed of 10,000 sheets / hour. The optimal humidity range is when the average humidity of the entire paperboard surface is between 9% and 11%, which corresponds to an ink viscosity of 2800 mPa·s, a printing plate-rubber blanket pressure of 9 kN / m, a drying temperature of 55℃, and a paper feeding speed of 12000 sheets / hour. When the average humidity of the entire paperboard surface is between 12% and 13%, it is considered a high humidity range, corresponding to an ink viscosity of 2500 mPa·s, a printing plate-rubber blanket pressure of 8 kN / m, a drying temperature of 65℃, and a paper feeding speed of 11,000 sheets / hour. The "humidity-printing parameter" mapping algorithm supports manual updates via the touchscreen of the human-computer interaction module or importing optimized parameters via the cloud interface.

5. The adaptive humidity-controlled carton printing device according to claim 1, characterized in that: The automatic ink adjustment subsystem includes: A miniature diluent pump (2) is installed on the top of the ink tank of the printing press and is connected to the ink tank through a silicone tube; Viscosity sensor (3), whose probe is inserted into the ink tank, is used to feed back ink viscosity data to the central control module in real time; This forms a closed loop for viscosity control, consisting of "detection-adjustment-feedback".

6. The adaptive humidity-controlled carton printing device according to claim 1, characterized in that: The pressure regulation subsystem (4) includes: The pneumatic pressure valve (5) is installed on the bracket between the printing plate cylinder and the blanket cylinder, and is connected to the original air source of the printing press through a pressure-resistant air pipe. The pneumatic pressure valve (5) is connected to the central control module. The pressure sensor (6) is fixed to the side of the roller bearing seat to detect the contact pressure between the printing plate cylinder and the blanket cylinder in real time and feed it back to the central control module.

7. The adaptive humidity-controlled carton printing device according to claim 1, characterized in that: The intelligent drying subsystem includes: Several electric heating tubes (7) are provided and are evenly distributed along the top and sides of the drying channel at the paper receiving end of the printing press; Variable frequency fans (8) are symmetrically installed on both sides of the drying channel to adjust the hot air speed; Temperature and humidity sensors (9) are installed at both the inlet and outlet of the drying channel at the paper receiving end of the printing press to provide feedback of environmental data to the central control module.

8. The adaptive humidity-controlled carton printing device according to claim 1, characterized in that: The paper feeding speed control subsystem includes: Servo motor driver (10) is adapted to the power of the paper feeding motor of the printing press paper feeding system, and controls the speed of the paper feeding motor through pulse signals; An electrostatic eliminator (11) is used to eliminate static electricity generated by low-humidity cardboard and is installed at the end of the paper feeder. An incremental encoder (12) is installed on the end of the paper feeding motor shaft via a coupling to collect the actual speed of the paper feeding motor in real time and to collect the actual speed of the motor in real time and feed it back to the central control module. A pneumatic pusher (13) is installed on the side of the paper feeding table and is connected to the central control module for pushing paperboard with excessive humidity to the waste collection trough.

9. The adaptive humidity-controlled carton printing device according to claim 1, characterized in that: The human-computer interaction module includes: The touchscreen is connected to the central control module and is used to display real-time humidity, current printing parameters, and device operating status. The alarm unit is an audible and visual alarm that automatically activates when the front-end humidity detection module detects that the paperboard humidity is >14% or <6%, and then links the paper feeding system to pause via the central control module. The data storage unit stores the humidity data, matching printing parameters, closed-loop correction records, and scrap rate data of each batch of cardboard in real time, and is equipped with a cloud interface.

10. A carton printing process based on the adaptive humidity-regulating carton printing apparatus according to any one of claims 1-9, characterized in that, Includes the following steps: S1: The cardboard to be printed is transported to the printing operation area through the paper feeding table of the printing machine. Before the cardboard enters the printing unit, multiple humidity sensors (1) of the front-end humidity detection module are activated to scan and detect the cardboard across the width of the cardboard, collect humidity data of each area of ​​the cardboard in real time, and transmit the detection data to the PLC main control unit of the central control module. S2: After receiving the humidity detection data from S1, the central control module's main control unit first filters and calibrates the data, calculates the average humidity value of the entire paperboard surface and the maximum humidity deviation value of each area, and then calls the "humidity-printing parameter" mapping algorithm of the parameter database unit to match the parameters. If the maximum humidity deviation is ≤ ±0.5%, directly match the target printing parameters corresponding to the average humidity value; If the maximum humidity deviation value is > ±0.5%, the local humidity compensation logic is invoked, and the width of the cardboard is divided into multiple detection areas according to the humidity sensor (1). The target printing parameters for each area are matched according to the humidity difference. Specifically: If the difference between the humidity value of a certain detection area and the average humidity value of the full width of the paperboard is ≥0.8%, the central control module sends an instruction to the intelligent drying subsystem corresponding to that area to increase the drying temperature by 5-8℃, and at the same time sends an instruction to the pressure regulation subsystem (4) to reduce the printing plate-rubber blanket pressure by 0.5-1kN / m, keep the ink viscosity unchanged, and keep the paper feeding speed unchanged. If the difference between the humidity value of a certain detection area and the average humidity value of the entire paperboard is ≤-0.8%, the drying temperature remains unchanged, the printing plate-rubber blanket pressure remains unchanged, the central control module sends an instruction to the automatic ink adjustment subsystem to increase the ink viscosity by 100-200 mPa·s, and at the same time sends an instruction to the paper feeding speed adjustment subsystem to reduce the paper feeding speed by 500-800 sheets / hour. If the difference between the humidity value of a certain detection area and the average humidity value of the entire paperboard surface is within ±0.8%, the drying temperature, printing plate-rubber blanket pressure, ink viscosity and paper feeding speed remain unchanged. S3: The central control module sends the target parameter instruction matched in S2 to the printing execution adjustment module, and each subsystem synchronously performs the adjustment. S3a: Start the micro diluent pump (2) of the automatic ink adjustment system to inject diluent into the ink tank. The viscosity sensor (3) collects the actual viscosity of the ink in real time and feeds it back to the central control module until the actual viscosity reaches the target value. S3b: The contact pressure between the printing plate cylinder and the blanket cylinder is adjusted by the pneumatic pressure valve (5) of the pressure regulation subsystem (4), and the pressure sensor (6) provides real-time feedback of the actual pressure until the pressure reaches the target value. S3c: Controls the heating element (7) of the intelligent drying subsystem to raise the temperature and the variable frequency fan (8) to adjust the speed. The temperature and humidity sensor (9) monitors the actual temperature and humidity data at the inlet and outlet of the drying channel in real time until the temperature of the drying channel reaches the target drying temperature. S3d: Adjust the paper feeding speed through the servo driver of the paper feeding speed control subsystem, and the encoder feeds back the motor speed until the paper feeding speed reaches the target value. If the paperboard humidity is <8%, the static eliminator (11) is started synchronously to eliminate the static electricity of the paperboard. S4: During the printing process, the central control module's closed-loop control unit continuously collects feedback from the printing execution adjustment module on ink viscosity, roller pressure, drying temperature, and paper feed speed, and compares the deviation with the target parameters. If the deviation is ≤3%, maintain the current parameters; If the deviation is greater than 3%, a correction command will be generated within 0.5 seconds. The correction command is as follows: Ink viscosity deviation > ±3%: Adjust the thinner pump flow rate; for every 1% deviation exceeding the deviation, increase the flow rate by ±2%. If the roller pressure deviation is greater than ±3%, adjust the output of the pneumatic pressure valve (5). For every 1% deviation, the pressure should be adjusted by ±1%. If the drying temperature deviation is > ±3℃: Adjust the heating element power; for every 1℃ deviation, adjust the power by ±3% or the fan speed by ±5%. Paper feed speed deviation > ±1%: Adjust the servo drive frequency; for every 0.5% deviation, adjust the frequency by ±0.3Hz. Correct the response time to ≤0.5 seconds, until the deviation is ≤3%; S5: If S1 detects that the paperboard humidity is >14% or <6%, the central control module triggers an alarm and controls the paper feeding system to stop. The paperboard exceeding the standard is pushed to the waste trough by the pneumatic pusher plate (13). After the paperboard exceeding the standard is removed, the front-end humidity detection module re-inspects the subsequent paperboard. After confirming that the humidity is 8-12%, the paper feeding is resumed.

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