Automatic ink skin cleaning system and method on printing machine

Abstract

The invention discloses an automatic ink skin cleaning system and method on a printing machine. The system comprises a mounting base, a guide rail, a lead screw, a sliding table, a servo motor, a speed reducer, a telescopic actuator, an ink scraping mechanism, a connecting rod, an online detection system and a controller. The online detection system collects an image facing a predetermined detection area of the plate cylinder, the controller processes the image, identifies an ink skin area and obtains image coordinates, a mapping relation is established based on calibration data of at least two known axial reference positions, the image coordinates are converted into axial position coordinates corresponding to the ink skin area, and the axial position coordinates are calculated. And outputting a coordinate effective mark and / or identification confidence. The ink scraping mechanism adopts a floating structure of a connecting frame, a guide sliding groove and a self-adaptive supporting sliding block, spring pre-tightening and feedback of a pressure sensor located in a force transmission path are matched, constant attaching force or limited force protection is achieved, and the ink scraping mechanism automatically retracts when exceeding the limit and gives an alarm. And a cleaning station can be selectively arranged to realize self-cleaning of the scraper.

Description

Technical Field

[0001] This invention relates to the field of ink skin cleaning and control technology for printing equipment, specifically to an automatic ink skin cleaning system and method for a printing press. Background Technology

[0002] In the continuous production process of offset printing, ink is transferred to the printing plate cylinder via the ink roller system to complete the image transfer. Due to factors such as ink application amount, ambient temperature and humidity, machine stoppage and local drying, excess ink can easily accumulate and dry on the roller surface or printing plate surface, forming an "ink skin". The ink skin migrates to the printing plate or printed product surface with the rotation of the cylinder, causing dirty plates, smeared plates, and printing defects, which seriously affect the printing quality. Once it occurs, it usually needs to be dealt with in time to avoid batch waste.

[0003] In existing technologies, the treatment of ink skin on printing plates / rollers is mainly done manually: operators clean the printing plates or related roller surfaces by wiping or scraping, or by using simple manual mechanisms. These methods generally suffer from low cleaning efficiency, high labor intensity, and the need for equipment to be rotating or operating at low speeds, requiring personnel to be close to the rotating rollers, posing significant safety hazards. Furthermore, manually judging the location and cleaning area of ​​the ink skin can easily lead to inaccurate positioning, repeated cleaning, or missed areas, resulting in long downtime and reduced production capacity.

[0004] In the field of printing equipment, existing solutions have proposed cleaning the ink skin formed by ink drying on the surface of printing cylinders during equipment operation using mechanical scraping. For example, patent document CN204278750U discloses an ink skin removal device for impression cylinders, which uses a cylinder to drive a piston rod, connecting rod, and scraper mechanism to swing, so that the scraper contacts the outer surface of the impression cylinder when needed and scrapes off the ink skin as the cylinder rotates. However, this solution mainly achieves the "contact / remove" scraping action, lacking online identification and coordinate positioning of the ink skin area, making it difficult to achieve axial precision cleaning of local ink skin areas on the printing cylinder surface; at the same time, it is also difficult to implement threshold permission based on detection results (such as width / confidence level), and interlock / abnormal retreat logic coupled with printing press safety signals.

[0005] Existing publicly available solutions attempt to control the scraper pressure through sensor feedback. For example, patent document number CN200954709Y uses a servo motor, synchronous belt, and ball screw to realize the up-and-down movement of the scraper component, and uses a pressure sensor to transmit the pressure to a computer for processing to control the pressure of the scraper on the steel mesh; However, this solution focuses more on pressure control issues such as "scraper against stencil" and does not involve online visual detection and positioning of ink skin on the printing plate cylinder. It also does not form an integrated closed-loop link of "detection coordinates → calibration mapping → axial positioning → positioning judgment → contact scraping". Therefore, if it is directly used for local cleaning of ink skin on the printing plate cylinder, it still has shortcomings such as reliance on manual or inaccurate positioning for determining the position of ink skin, and lack of access thresholds for different sizes / shapes of ink skin. Patent document number CN221137267U is still biased towards manual operation or semi-automatic operation, and lacks online detection and recognition of ink skin (or foreign object) areas and coordinate output. It also lacks constant force / limited force closed-loop control and over-limit avoidance of the contact force of the cleaning part, making it difficult to balance the protection of the printing plate cylinder surface and stable scraping effect. Patent document number CN214563852U mainly focuses on ink cleaning of the scraper body, and is not for online recognition and axial positioning scraping of "ink skin area" on the printing plate cylinder.

[0006] Regarding the field of printing press cleaning, there are also solutions that utilize sprayed solvents to clean the ink roller assembly. For example, the cleaning device disclosed in US20170320319A1 supplies a cleaning solution containing surfactants or volatile organic solvents to the ink roller assembly, cleaning it through nozzles; Patent document number CN97100898.1 is used to clean the outer cylindrical surface of the roller. The cleaning device includes a push rod for pressing a cleaning cloth onto the corresponding outer cylindrical surface, an adjustment element for positioning the push rod in a contact position, and an elastically molded guide rail. This guide rail guides the cleaning cloth and presses it onto the outer cylindrical surface across the entire width of the roller. However, this method of pressing the cleaning cloth onto the surface is not very effective. Although the cleaning range is wide, it cannot be directionally scraped out, and cannot be cleaned completely in one go.

[0007] Regarding the detection / monitoring of printing presses, there are also publicly disclosed technologies for detecting the loading status of printing plates. Patent document CN101896347A provides a monitoring system for detecting whether a partially loaded printing plate exists at each position on the printing plate cylinder during a loading cycle. It determines the presence of a printing plate through a discrete vacuum circuit and suction elements associated with the plate position, and can be used to indicate the loading status or terminate the loading process. This type of monitoring technology detects the loading status of the printing plate itself, not the ink skin on the printing plate surface.

[0008] Based on the above analysis of existing technologies, even with partially mechanized scraping devices, the lack of online detection and positioning of the ink-covered area typically necessitates manual observation and adjustment of the scraping position. Furthermore, the lack of effective control over the blade's contact force means that the contact pressure can fluctuate due to assembly errors, mechanism clearances, and roller runout, potentially leading to insufficient scraping (ink residue) or excessive contact (aggravating plate / roller wear or even damaging the plate). The absence of interlocking and anomaly handling mechanisms makes it difficult to promptly retreat and trigger alarms in cases of limit triggering, signal abnormalities, or pressure over-limits, resulting in insufficient safety and reliability. Therefore, given the limitations of existing technologies, there is an urgent need for an automated cleaning solution capable of online detection and precise axial positioning of the ink-covered area, constant / limited force control of the blade's contact force, and interlocking protection and anomaly avoidance capabilities to improve cleaning efficiency, stability, and operational safety. Summary of the Invention

[0009] The technical problem this invention aims to solve is to overcome existing defects and provide an automatic ink removal system and method for printing presses. This system forms a strongly coupled closed-loop link between "online detection and identification—coordinate calibration and mapping—axial closed-loop positioning and determination—constant force / limited force scraping—interlocking and abnormal retreat—optional self-cleaning cleaning station." The online detection system acquires images of the roller surface and outputs the coordinates of the ink-covered area. The controller establishes a mapping relationship based on at least two axial reference positions to calculate the axial position coordinate X and performs a positioning determination before allowing scraping. The scraping mechanism adopts a floating structure of connecting frame-guide groove-adaptive support slider, combined with spring preload and a pressure sensor located on the force transmission path to achieve constant / limited force control of the scraping force, effectively solving the problems in the background technology.

[0010] To achieve the above objectives, the present invention provides the following technical solution: an automatic ink removal system and method for a printing press, comprising a mounting base, a guide rail, a lead screw, a slide table, a servo motor, a reducer, a telescopic actuator, an ink scraping mechanism, a printing plate cylinder, a connecting rod, an online detection system, and a controller, characterized in that: the guide rail is fixedly mounted on the mounting base, and the mounting base is fixed to the printing press wall panel; the slide table is mounted on the guide rail and reciprocates linearly along the extension direction of the guide rail; the lead screw is arranged along the extension direction of the guide rail and is connected to the slide table via a lead screw nut; the servo motor is connected to the lead screw via a reducer to drive the lead screw to rotate and drive the slide table to move, thereby causing the ink scraping mechanism to move axially along the printing plate cylinder; the telescopic actuator is fixedly mounted on the slide table, and the telescopic ends of the ink scraping mechanism and the telescopic actuator are connected. The connection allows the doctor blade mechanism to extend towards and scrape the printing plate cylinder, and to retract away from the cylinder. Both ends of the connecting rod are fixedly connected to the printing press wall panel. An online detection system is fixedly mounted on the connecting rod and positioned near the printing plate cylinder within a predetermined detection area facing it, for acquiring images of the predetermined detection area. The controller is electrically connected to the online detection system, the servo motor, and the telescopic actuator, and receives interlocked inputs including at least an emergency stop signal, a limit signal, a safety door signal, and an operating mode signal. The controller is configured to process the image to identify the ink skin area and obtain the corresponding image coordinates, and establish the image coordinates and axial position based on at least two known axial reference positions spaced apart along the printing plate cylinder axis through calibration. The correspondence between coordinates is established, converting the image coordinates into the axial position coordinate X corresponding to the ink coating area, and outputting a valid coordinate flag and / or recognition confidence level. Only when the valid coordinate flag is valid and / or the recognition confidence level meets a preset threshold, and the interlock input meets the allowed cleaning conditions, the servo motor is controlled to drive the slide table in a closed loop to the position corresponding to the axial position coordinate X and perform a positioning judgment. The positioning judgment includes at least the absolute value of the position error being less than a preset threshold ε and the holding time being not less than a preset time t. After the positioning judgment is passed, the telescopic actuator is controlled to extend so that the ink scraping mechanism is against the printing plate cylinder for scraping. After scraping is completed, the telescopic actuator is controlled to retract and the slide table is controlled to return to the standby position. The ink scraping mechanism includes a connecting frame, an adaptive support slider, a spring, and a pressure... Force sensor and scraper; the connecting frame is connected to the telescopic end of the telescopic actuator, which can be connected by thread or by clamping ring, movable pin or quick connector and other components for quick locking connection; and the connecting frame is provided with a guide groove extending along the contact direction; the adaptive support slider slides in cooperation with the guide groove so that the scraper can generate floating displacement in the contact direction; the spring is set between the connecting frame and the adaptive support slider to apply preload to the adaptive support slider; the pressure sensor is set at the force-bearing end of the spring and located on the force transmission path of the scraper contact, the pressure sensor is located between the spring and the connecting frame and on the force transmission path of the scraper contacting the printing plate cylinder (9), the pressure sensor is electrically connected to the controller and is used to output the scraper contact force or pressure feedback;The controller adjusts the output of the telescopic actuator based on the feedback of the contact force or pressure, keeping the contact force constant or maintained within a preset range. When the contact force or pressure exceeds the preset upper limit F_hi, the controller retracts the telescopic actuator and outputs an alarm.

[0011] Furthermore, the telescopic actuator is any one of a cylinder, an electric push rod, or an electromagnetic push rod.

[0012] Furthermore, the connecting frame and the telescopic end of the telescopic actuator are detachably connected, and the detachable connection is any one of the following: threaded connection, clamping ring connection, movable pin connection, or quick connector connection.

[0013] Furthermore, the scraper includes a scraper blade and a stainless steel back plate. The adaptive support slider is provided with a mounting groove, and the stainless steel back plate is inserted into the mounting groove and fixed by locking bolts. The groove not only serves to stably guide the adaptive support slider, but also prevents the adaptive support slider from sliding, ensuring structural stability during adaptive sliding.

[0014] Furthermore, the scraper blade is made of polyurethane and is fixed to the stainless steel backing plate by casting, hot pressing, or bonding. The blade edge is rounded, chamfered, or beveled. Increased hardness improves scraping ability, while decreased hardness reduces the risk of wear on the printing plate. The hardness range can be selected according to the material and working conditions. The scraper blade has a hardness of 70–95 Shore A and a thickness of 1–5 mm, commonly 2–3 mm, and is combined with a constant pressure structure to effectively scrape off the ink skin without damaging the printing plate cylinder.

[0015] Furthermore, the online inspection system includes an industrial camera and a light source, which are fixedly mounted on a connecting rod. The field of view of the industrial camera covers the predetermined inspection area, and the light source is used to provide illumination to the predetermined inspection area to enhance the imaging difference between the ink skin and the normal ink film.

[0016] Industrial cameras can be smart cameras with built-in processing capabilities, or they can be processed by external industrial control computers / PLCs.

[0017] Furthermore, it also includes a cleaning block for the cleaning station. The cleaning block is fixed to the inside of the printing press wall panel and has a positioning groove. The outer end of the positioning groove has a flared structure. A through hole is provided below the positioning groove to allow residual ink skin to fall into the collection tank. The controller is configured to control the slide to enter the cleaning station after scraping is completed, so that the scraper enters the positioning groove and rubs against the inner wall of the positioning groove to remove the residual ink skin on the scraper. The cleaning block can be made of solvent-resistant rubber, polyurethane, or nylon. After the ink skin is cleaned, the scraping mechanism enters the cleaning station under the drive of the servo motor, and the scraper enters the positioning groove. During the entry process, the scraper makes close contact with the positioning groove. Under the action of friction, the ink skin on the scraper is scraped off and falls into the collection tank below the cleaning block. In order to further improve the cleaning effect, a scraper can be set at the inlet on the upper surface of the positioning groove to improve the cleaning effect. Alternatively, a spray nozzle can be selected to spray cleaning fluid onto the cleaning block area in a short pulse manner. The cleaning fluid can be discharged through the through hole or by using an adsorption port set below the collection tank and connected to a negative pressure pipeline.

[0018] Furthermore, an automatic ink removal method for a printing press includes the following steps: S1, The controller obtains the interlock input and performs an interlock determination; S2, the online detection system acquires images of the predetermined detection area, the controller performs ink skin recognition to obtain the coordinates of the ink skin area image and generates a valid coordinate flag and / or recognition confidence level; S3, the controller converts the image coordinates into axial position coordinates X based on the mapping relationship established by at least two known axial reference positions; S4, when the coordinate valid flag is valid and the interlock meets the allowed cleaning conditions, control the servo motor to drive the slide table to move in closed loop to X and execute the position determination. The position determination includes at least the absolute value of the position error being less than ε and the holding time being not less than t. S5, after the positioning is confirmed, the telescopic actuator is extended to make the scraper stick to the printing plate cylinder for scraping, and the output of the telescopic actuator is adjusted according to the feedback of the pressure sensor to keep the sticking force constant or within the preset range; when the sticking force or pressure exceeds the preset upper limit F_hi, the telescopic actuator is retracted and an alarm is triggered. S6, after scraping is completed, control the telescopic actuator to retract and control the slide to return to the standby position; S7. If any of the above steps result in failure to reach the target position, interlock failure, limit triggering, excessive contact force / pressure, abnormal detection signal, or communication failure, perform abnormal handling. Abnormal handling includes at least stopping the slide movement and controlling the telescopic actuator to retract and exit the contact surface, while outputting an alarm and / or recording fault information.

[0019] Before or after step S6, the controller controls the slide to enter the cleaning station, so that the scraper enters the positioning groove of the cleaning block and rubs against the inner wall of the positioning groove to remove the residual ink on the scraper, and the residual ink falls into the collection tank through the through hole.

[0020] When the controller determines that the slide table does not meet the positioning conditions, such as the axial position error not being less than the preset threshold ε and remaining there for a preset time t, the system should not directly enter the contact scraping step, but instead execute the "not in position" exception handling logic: First, the retry mechanism is triggered, the controller reissues the motion command and performs the positioning determination again; when it is detected that the limit is not triggered, the positioning timeout threshold is not exceeded, and the number of retries does not exceed the upper limit, the process returns to step S4, the slide table moves to X and performs the positioning determination, and a retry is performed; if the limit is triggered, the positioning timeout threshold is exceeded, or the number of retries exceeds the upper limit, the controller executes an alarm and records, and instructs the system to retreat / reset, and then the process proceeds to step S6 or step S7.

[0021] When the controller detects that the contact pressure exceeds the preset upper limit F_hi during the contact scraping process, it determines that it is an overpressure condition and immediately activates the protection strategy: the controller immediately sends a retraction command to the telescopic actuator to disengage the scraping mechanism from the printing plate cylinder, and at the same time outputs an alarm signal and records the overpressure event, including the pressure peak, duration and current position, etc. After the overpressure retraction is completed, the process preferably proceeds to step S6, and then further to step S7; in the implementation that needs to support automatic recovery, it can also return to the detection step for the next round of processing after completing S6 if preset conditions are met, such as the number of overpressures has not exceeded the limit and the re-inspection has passed.

[0022] Furthermore, the controller is configured to control the online detection system (11) to collect a re-inspection image and perform re-inspection identification after performing a scraping action; when the re-inspection result shows that the ink skin has not been completely removed, additional cleaning is triggered and re-inspection is performed again after the additional cleaning; wherein, the controller sets a maximum number of additional times N_max and / or a maximum closed-loop time T_max for the re-inspection closed loop, and when the re-inspection is still not passed after reaching the N_max and / or T_max, an alarm is output and / or fault information is recorded, and the telescopic actuator (1) is controlled to retract so that the scraping mechanism (8) exits contact with the printing plate cylinder (9).

[0023] Between step S5 and step S6, a re-inspection closed-loop step is performed: the online detection system (11) is controlled to collect re-inspection images and perform re-inspection identification; when the re-inspection result fails, additional cleaning is performed and re-inspection images are collected again for re-inspection; the maximum number of additional times N_max and / or the maximum closed-loop time T_max are set for the re-inspection closed loop. When the re-inspection fails after reaching N_max and / or T_max, an alarm is output and / or fault information is recorded, and the telescopic actuator (1) is controlled to retract and exit the contact surface before proceeding to step S6 or step S7.

[0024] Compared with the prior art, the beneficial effects of the present invention are: 1. This application uses an online detection system to acquire images of the predetermined detection area of ​​the printing plate cylinder. The controller processes the images to identify the ink skin area and obtain the image coordinates. Based on the calibration data of at least two known axial reference positions, a mapping relationship is established to convert the image coordinates into the axial position coordinates X corresponding to the ink skin area. This enables the doctor blade mechanism to directly align with the ink skin area according to the coordinates instead of relying on manual visual positioning, fundamentally reducing the probability of misjudgment, missed scraping, or repeated scraping, shortening the search and alignment time, improving processing efficiency and consistency, and thus reducing printing defects such as dirty plates and smeared plates caused by ink skin, improving printing quality stability and continuous production capacity.

[0025] 2. The controller of this application receives interlock inputs such as emergency stop, limit switch, protective door, and operating mode. Only when the coordinates are valid and the interlock meets the allowable cleaning conditions will the drive slide be allowed to move in a closed loop to the target axial position. The "position error is less than the threshold ε and the holding time is not less than t" is used as the prerequisite for contact scraping. This mechanism strongly binds the scraping action with the safety and positioning status of the equipment, which can effectively avoid accidental contact when the equipment is in an abnormal state or the scraping mechanism has not accurately reached the target position. This reduces the safety hazards of personnel approaching rotating parts, reduces scraping offset, damage to the plate, or cleaning failure caused by positioning deviation, and improves the reliability and controllability of the system operation.

[0026] 3. The scraping mechanism of this application features a connecting frame, guide groove, and adaptive support slider that slide together to allow the scraper blade to float in the contact direction. Contact force / pressure feedback is obtained through spring preload and a pressure sensor located on the force transmission path. The controller adjusts the output of the telescopic actuator accordingly to keep the contact force constant or within a preset range. When the contact force / pressure exceeds the upper limit F_hi, the scraper blade automatically retracts and triggers an alarm. This counteracts contact force fluctuations caused by roller runout, assembly errors, and mechanism gaps, preventing ink residue due to insufficient contact force and wear or damage to the printing plate due to excessive contact force. This achieves the effect of "clean scraping without damaging the printing plate." Simultaneously, the force-limiting retraction protection reduces the risk of failure and extends the service life of the scraper blade and roller.

[0027] 4. This application can be equipped with a cleaning block and positioning groove at the cleaning station, with a flared inlet for inlet feeding. After scraping is completed, the scraper is driven into the positioning groove and rubs against the groove wall to remove residual ink skin, and the residual ink falls into the collection groove through the through hole. If necessary, it can also be combined with pulse cleaning by spray nozzles or negative pressure adsorption recovery. This solution can complete the self-cleaning of the scraper under non-stop or short-stop conditions, reduce the re-contamination caused by the secondary introduction of residual ink from the scraper, reduce the frequency of manual cleaning and downtime maintenance, improve the cleanliness of the equipment and the on-site environment, thereby improving the continuous operation capability and overall production efficiency of the system. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a side view of the overall structure of the present invention; Figure 3 This is a schematic diagram of the ink scraping mechanism of the present invention; Figure 4 This is a side view of the ink scraping mechanism of the present invention; Figure 5 This is a schematic diagram of the cleaning block structure of the present invention; Figure 6 This is a block diagram illustrating the control principle of the present invention; Figure 7 This is a flowchart of the method of the present invention.

[0029] In the diagram: 1 Telescopic actuator, 2 Guide rail, 3 Lead screw, 4 Slide table, 5 Servo motor, 6 Reducer, 7 Mounting base, 8 Scraper mechanism, 9 Printing plate cylinder, 10 Connecting rod, 11 Online detection system, 12 Cleaning block, 13 Scraper blade, 14 Mounting groove, 15 Adaptive support slider, 16 Guide groove, 17 Connecting frame, 18 Pressure sensor, 19 Spring, 20 Locking bolt, 21 Stainless steel back plate, 22 Positioning groove, 23 Through hole. Detailed Implementation

[0030] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0031] Example 1: Overall Structure and Installation Method of Automatic Ink Cleaning System As attached Figure 1-7As shown, an automatic ink cleaning system for a printing press includes a mounting base 7, a guide rail 2, a lead screw 3, a slide table 4, a servo motor 5, a reducer 6, a telescopic actuator 1, an ink scraping mechanism 8, a printing plate cylinder 9, a connecting rod 10, an online detection system 11, and a controller.

[0032] Mounting base 7 is fixed to the printing press wall panel, and guide rail 2 is fixedly set on mounting base 7; slide table 4 is mounted on guide rail 2 and can reciprocate linearly along the extension direction of guide rail 2; lead screw 3 is set along the extension direction of guide rail 2 and is connected to slide table 4 for transmission; servo motor 5 is connected to lead screw 3 for transmission through reducer 6, and servo motor 5 drives lead screw 3 to rotate under the control of controller, thereby driving slide table 4 to achieve closed-loop positioning movement (axial movement) along the direction of guide rail 2.

[0033] The telescopic actuator 1 is mounted on the slide table 4, and its telescopic end is connected to the doctor blade mechanism 8, so that the doctor blade mechanism 8 can move closer to or away from the outer surface of the printing plate cylinder 9 in the contact direction under the drive of the telescopic actuator 1; the telescopic actuator 1 can be any one of a cylinder, an electric push rod or an electromagnetic push rod to adapt to the power and control requirements of different equipment.

[0034] The connecting rod 10 is fixed to the inside of the printing press wall panel or forms a fixed connection with the mounting base 7. The online inspection system 11 is fixedly installed on the connecting rod 10 and faces the predetermined inspection area of ​​the printing plate cylinder 9. The online inspection system 11 includes an industrial camera and a light source. The field of view of the industrial camera covers the predetermined inspection area, and the light source is used to provide illumination to the area to enhance the imaging difference between the ink skin and the normal ink film.

[0035] The controller is electrically connected to the online detection system 11, the servo motor 5 and the telescopic actuator 1 respectively, and receives interlock input signals. The interlock inputs include at least: emergency stop signal, limit signal, protective door signal and operating mode signal. The controller is used to realize closed-loop control of detection-positioning-attach scraping, and performs retreat and alarm recording in case of abnormality.

[0036] In a recommended installation arrangement, the slide 4 is set to a standby position (non-scraping position). When the system is not performing a cleaning task, the doctor blade mechanism 8 maintains a gap with the printing plate cylinder 9 to avoid interfering with the printing process.

[0037] Example 2: Floating Structure and Constant / Limiting Force Control of the Scalpel Mechanism The doctor blade mechanism 8 includes a connecting frame 17, an adaptive support slider 15, a guide groove 16, a spring 19, a pressure sensor 18, and a doctor blade.

[0038] The connecting frame 17 is connected to the telescopic end of the telescopic actuator 1; the connection method can be selected as threaded connection, clamping ring connection, movable pin connection or quick connector connection, so as to facilitate maintenance and replacement; the connecting frame 17 is provided with a guide groove 16 extending along the contact direction, and the adaptive support slider 15 slides with the guide groove 16, so that the scraper can generate floating displacement in the contact direction, thereby absorbing the contact deviation caused by assembly error, roller runout and mechanism clearance, and improving the contact stability.

[0039] Spring 19 is positioned between connecting frame 17 and adaptive support slider 15 to provide preload force to the scraper. Pressure sensor 18 is positioned at the force-bearing end of spring 19 and on the force transmission path where the scraper contacts the blade. Pressure sensor 18 is electrically connected to the controller and is used to output scraper contact force or pressure feedback signal. The controller adjusts the output of telescopic actuator 1 based on this feedback to keep the contact force constant or within a preset range. When the contact force or pressure exceeds the preset upper limit F_hi, the controller controls telescopic actuator 1 to retract and outputs an alarm, achieving force limit protection and automatic retreat.

[0040] In a preferred implementation, the controller uses the error e = F_set − F_meas between the measured value F_meas output by the pressure sensor 18 and the target contact force F_set as the control quantity to perform closed-loop regulation on the output of the telescopic actuator 1, so that the contact force is stabilized near F_set or within a preset range [F_lo, F_hi]. To improve anti-interference capability, the pressure signal can be acquired according to a preset sampling period and filtered (e.g., moving average or first-order low-pass filter), and a debouncing time is set to avoid transient noise triggering malfunctions.

[0041] When the telescopic actuator 1 is an electric push rod or an electric cylinder, the controller can adopt a hybrid control strategy of position / speed and force. For example, displacement control can be used to gradually approach the contact in the initial stage, and after contact, force closed-loop control can be switched and the output displacement increment can be adjusted by PID or segmented proportional adjustment. When the telescopic actuator 1 is a cylinder, an electro-proportional valve or a pressure regulating valve can be used to regulate the air pressure. The controller adjusts the valve opening according to e to achieve the contact force closed loop. When F_meas>F_hi is detected, the telescopic actuator 1 is immediately driven to retract, so that the doctor blade is disengaged from the printing plate cylinder 9, thereby achieving overpressure protection.

[0042] The scraper preferably includes a scraper blade 13 and a stainless steel back plate 21. The adaptive support slider 15 is provided with a mounting groove 14. The stainless steel back plate 21 is inserted into the mounting groove 14 and fixed by locking bolts 20 to form a stable and reliable assembly structure. The scraper blade 13 can be made of polyurethane material and is connected and fixed to the stainless steel back plate 21 by a casting process. The blade edge of the scraper blade 13 can be rounded, chamfered, or beveled. The hardness of the scraper blade 13 is preferably 70-95 Shore A, and the thickness is 1-5 mm (commonly 2-3 mm). It is combined with the above-mentioned constant force / limiting force structure to reduce the risk of wear on the surface of the printing plate cylinder 9 while effectively scraping off the ink skin.

[0043] Example 3: Online detection, coordinate validity and axial coordinate mapping The online inspection system 11 acquires images of the predetermined inspection area of ​​the printing plate cylinder 9. The controller processes the images to identify the ink skin area and obtain the corresponding image coordinates, while generating a valid coordinate mark and / or identification confidence level.

[0044] Optionally, the image coordinates u and v are pixel coordinates in the imaging plane of the industrial camera, where the u-axis corresponds to the axial direction of the printing plate cylinder (consistent with the moving direction of the slide 4), and the v-axis corresponds to the radial / circumferential projection direction. To reduce the impact of illumination changes on recognition stability, the controller can first preprocess the acquired image. The preprocessing includes at least: noise reduction filtering (such as median filtering or Gaussian filtering), brightness normalization, or local contrast enhancement. Subsequently, the controller extracts candidate regions based on the differences in grayscale, color, or texture between the ink skin and the normal ink film. For example, after converting the image to grayscale or HSV color space, threshold segmentation is performed, and morphological opening / closing operations are combined to remove small noise points and fill holes. Then, connected component analysis is performed on the binary results to obtain one or more candidate connected components.

[0045] In one implementation, the controller uses the largest connected component (or the k largest connected components by area) as the candidate region for ink removal, and uses the centroid coordinates (u_c, v_c) or the center of the circumscribed rectangle of the candidate region as the "ink removal region image coordinates". The valid coordinate flag can be generated according to at least one of the following rules: the area A of the candidate region satisfies A≥A_min; the aspect ratio of the candidate region satisfies the set interval; the centroid drift of the candidate region in N consecutive frames is ≤δ; and / or the recognition confidence C≥C_min (the confidence can be obtained from the segmentation score, connected component stability, or classifier output). When no candidate region that meets the rules is detected, the controller outputs a coordinate invalid flag and prohibits the positioning and scraping actions, thereby avoiding accidental scraping or empty scraping.

[0046] Optionally, A_min, N, δ, and C_min can be obtained by calibration using pre-existing sample images and trial operation data: for example, A_min can be 10 to 2000 pixels (or set according to 0.01% to 2% of the pixel area of ​​the detection region), N can be 2 to 10 frames, δ can be 1 to 10 pixels, and C_min can be 0.6 to 0.95; specific thresholds can be adjusted according to camera resolution, field of view size, ink skin morphology, and ambient lighting conditions.

[0047] The controller establishes a mapping relationship based on calibration data from at least two known axial reference positions, converting image coordinates into axial position coordinates X corresponding to the ink coating area. The calibration data can be obtained by moving the slide 4 to multiple known axial reference positions and acquiring images to obtain the corresponding image coordinates. In the simplest implementation, a linear mapping of two-point calibration (e.g., X=a·u+b, where u is the image coordinate) can be used, or a lookup table interpolation or piecewise fitting of multi-point calibration can be used to adapt to more complex field distortion and installation errors. The axial position coordinate X can be defined as the coordinate relative to the axial zero point of the equipment. The controller outputs the target position and drives the slide 4 to the closed loop to the point. The axial zero point can be determined by the zero-return position of the slide 4. The zero-return position can be the position of the end origin sensor or a preset mechanical reference position near the end limit. The positive direction of the axial coordinate X is preferably along the extension direction of the guide rail 2 (from the standby position to the cleaning station or from one end to the other). The controller uses this zero point and positive direction as a unified coordinate system reference for coordinate conversion and motion control.

[0048] Optionally, the calibration process includes at least the following steps: After the equipment is installed or maintained, the controller controls the slide 4 to move sequentially to two or more known axial reference positions X_i (i=1…n), and acquires the detection area image of the printing plate cylinder 9 at each reference position, extracting the corresponding reference pixel coordinates u_i; the controller establishes a (u_i, X_i) correspondence and generates mapping parameters accordingly; for linear mapping of two-point calibration, it can be obtained by solving (a, b) satisfying X_1=a·u_1+b and X_2=a·u_2+b; for multi-point calibration, (u_i, X_i) can be stored in the form of a lookup table, and the axial coordinates X can be output by linear interpolation or spline interpolation during runtime.

[0049] To improve long-term stability, the controller can also be configured to trigger recalibration or parameter correction when preset conditions are met, such as: the cumulative running time reaches a threshold, a persistently large mapping error is detected, after camera / light source replacement, or after equipment vibration / disassembly and maintenance; during recalibration, the above steps can be reused to update the mapping parameters, so that the conversion relationship from image coordinates to axial coordinate X continues to meet the accuracy requirements.

[0050] Example 4: Interlocking gate control, arrival determination, retry before arrival and abnormal backoff The controller receives interlock inputs and performs interlock determination; the interlock inputs include at least emergency stop signals, limit signals, protective door signals, and operating mode signals; the controller only allows movement and contact actions when the interlock meets the permissible cleaning conditions, thereby strongly binding the operation actions with the equipment safety status.

[0051] In one implementation, the "permitted cleaning conditions" include at least the following combination of conditions: the emergency stop signal is not triggered, the slide 4 is not triggered in any direction limit, the printing press protective door is closed, the printing press is in a maintenance or automatic cleaning operation mode, and the main drive of the printing press is within a safe speed range or in a stopped state; when any condition is not met, the controller prohibits the slide movement and contact action, and outputs an alarm and / or records the reason for the interlock not being met.

[0052] When the coordinate valid flag is valid and the interlock meets the allowable cleaning conditions, the controller controls the servo motor 5 to drive the slide 4 to move in a closed loop to the position corresponding to the axial position coordinate X and executes the positioning determination; the positioning determination includes at least: the absolute value of the position error is less than the preset threshold ε and the holding time is not less than the preset time t; optionally, the positioning determination can also be combined with conditions such as speed threshold, servo following error and limit status to improve the positioning reliability.

[0053] Optionally, the position error threshold ε and the holding time t can be set according to the lead screw lead, encoder resolution and printing press cycle time. For example, ε can be 0.1 to 2 mm and t can be 50 to 500 ms; the position timeout threshold T_pos can be 0.5 to 5 s and the maximum number of retries N_retry can be 1 to 5 times; when the controller performs the position determination, it can also combine the speed threshold (e.g., the slide speed is less than the preset value) and the servo follow error threshold for comprehensive determination to avoid misjudging the position when the slide is still in the dynamic adjustment stage.

[0054] When the position is not determined to be in position, the controller preferably performs a retry: if the limit is not triggered, the position timeout threshold is not exceeded, and the number of retries does not exceed N_retry, the process returns to step S4 to reissue the motion command and determine the position again; if the limit is triggered, T_pos is exceeded, or the number of retries exceeds N_retry, the controller outputs an alarm and records the fault information, performs a backoff / reset action, and transfers the process to step S6 or step S7.

[0055] When the controller detects that the contact pressure exceeds the preset upper limit F_hi during the contact scraping process, it determines that the overpressure condition is in effect and immediately activates the protection strategy: the controller immediately sends a retraction command to the telescopic actuator to disengage the scraping mechanism from the printing plate cylinder, and at the same time outputs an alarm signal and records the overpressure event (including pressure peak, duration and current position, etc.); after the overpressure retraction is completed, the process preferably proceeds to step S6 (retracting the scraping mechanism, optionally entering the cleaning station for self-cleaning), and further proceeds to step S7 (resetting / ending or waiting for the next trigger); in the implementation that needs to support automatic recovery, it can also return to the detection step for the next round of processing after completing S6 if the preset conditions are met (e.g., the number of overpressures has not exceeded the limit and the re-inspection has passed).

[0056] In addition, if an interlock failure, limit triggering, abnormal detection signal, or communication failure occurs in any of the above steps, the controller will perform abnormal handling. Abnormal handling includes at least: stopping the movement of the slide table 4 and controlling the telescopic actuator 1 to retract and exit the contact surface, while outputting an alarm and / or recording fault information to ensure the safety of equipment and personnel.

[0057] Example 5: Self-cleaning of the scraper and collection of residual ink at the cleaning station The system may also include a cleaning block 12 for the cleaning station; the cleaning block 12 is fixed to the inside of the printing press wall panel and is provided with a positioning groove 22, the outer end of the positioning groove 22 is a flared structure to facilitate the introduction of the scraper; a through hole 23 is provided below the positioning groove 22 so that the residual ink skin falls into the collection tank under the action of gravity.

[0058] The controller can be configured to control the slide 4 to enter the cleaning station after scraping is completed, so that the scraper enters the positioning groove 22 and rubs against the inner wall of the positioning groove 22 to remove the residual ink on the scraper, and the residual ink falls into the collection tank through the through hole 23; the cleaning block 12 can be made of solvent-resistant rubber, polyurethane or nylon to improve the cleaning effect and corrosion resistance when in contact with the scraper.

[0059] To further improve the cleaning effect, a scraper can be installed at the inlet on the upper surface of the positioning groove 22; a spray nozzle can also be installed to spray cleaning fluid onto the cleaning block 12 area in a short-time pulse mode, and the cleaning fluid can be discharged through the through hole 23; or an adsorption port can be installed below the collection tank and connected to a negative pressure pipeline to achieve the suction and recovery of residual ink; the execution sequence of the cleaning station can be set to be performed before or after step S6, or it can be incorporated into S6 as an integrated action of "retraction + self-cleaning + return to standby".

[0060] Example 6: Method Example An automatic ink removal method for a printing press, applied to the automatic ink removal system of any of the above embodiments, includes the following steps: S1: The controller acquires the interlock input and performs an interlock determination; S2: The online detection system 11 acquires images of the predetermined detection area, and the controller performs ink skin recognition to obtain the coordinates of the ink skin area image and generates a valid coordinate flag and / or recognition confidence level; S3: The controller converts the image coordinates into axial position coordinates X based on the mapping relationship established by at least two known axial reference positions. S4: When the coordinate valid flag is valid and the interlock meets the allowable cleanup conditions, control the servo motor 5 to drive the slide table 4 to move in a closed loop to X and execute the position determination. The position determination includes at least the absolute value of the position error being less than ε and the holding time being not less than t. S5: After the positioning is confirmed, the telescopic actuator 1 is extended to make the scraper stick to the printing plate cylinder 9 for scraping. The output of the telescopic actuator 1 is adjusted according to the feedback of the pressure sensor 18 to keep the sticking force constant or within the preset range. When the sticking force or pressure exceeds the preset upper limit F_hi, the telescopic actuator 1 is retracted and an alarm is triggered. S6: After scraping is completed, control the telescopic actuator 1 to retract and control the slide 4 to return to the standby position; in an optional embodiment, before or after S6, control the slide 4 to enter the cleaning station, so that the scraper enters the positioning groove 22 of the cleaning block 12 and rubs against the groove wall to remove residual ink skin, so that the residual ink skin falls into the collection groove through the through hole 23. Alternatively, at least one of the following criteria may be used to determine this: (1) The scraping duration reaches the preset duration T_scrape; (2) The contact force enters the stable range and remains for a preset time (e.g., F_meas falls into [F_lo, F_hi] and the fluctuation amplitude is less than the threshold and continues for Δt). (3) After the scraping is completed, the controller re-acquires the image of the detection area for re-examination and determines that the area of ​​the candidate ink skin region has decreased to below the threshold or has disappeared; (4) The load characteristics (such as current / torque) of the servo motor or actuator meet the preset variation conditions. The above criteria can be used alone or in combination to ensure the cleaning effect while taking into account the production cycle.

[0061] S7: If any of the above steps results in failure to reach the target position, interlock failure, limit triggering, excessive contact force / pressure, abnormal detection signal, or communication failure, perform abnormal handling. Abnormal handling includes at least stopping the movement of slide 4 and controlling the telescopic actuator 1 to retract and exit the contact surface, while simultaneously outputting an alarm and / or recording fault information.

[0062] Example 7: An Automatic Ink Cleaning Method Based on Re-inspection Closed Loop In this embodiment, after completing one scraping action, the controller does not directly end the cleaning process, but introduces a re-inspection closed loop to accept the cleaning effect, and automatically adds cleaning when necessary, thereby forming a closed-loop control of "inspection-cleaning-acceptance-re-cleaning".

[0063] Specifically, after the system completes the interlock determination, ink skin identification, and positioning to the axial position coordinate X according to steps S1 to S4, and the positioning determination is passed, step S5 is executed to make the scraping mechanism come into contact with the printing plate cylinder for scraping. After one scraping action is completed, the controller enters the re-inspection closed-loop process, including the following steps: a (Re-inspection Acquisition and Re-inspection Recognition): The controller controls the online detection system to acquire re-inspection images. The re-inspection area can be the same as the predetermined detection area in step S2, or it can be a local area (ROI) containing the target location X. The controller processes the re-inspection images using the same or equivalent recognition rules as in step S2 to obtain candidate re-inspection ink skin regions and their image coordinates, and generates a valid re-inspection coordinate flag and / or a re-inspection recognition confidence score.

[0064] b (Re-inspection pass determination): The controller determines whether the re-inspection passes based on the re-inspection results; in one embodiment, the re-inspection passes at least if any of the following conditions are met: no ink skin candidate area that meets the validity rules is detected; or the area A of the re-inspected ink skin candidate area is less than the preset threshold A_pass; or the re-inspection identification confidence is lower than the threshold C_pass and the validity conditions are not met in M ​​consecutive re-inspections, thereby suppressing misjudgments caused by occasional noise.

[0065] c (Appendix Cleanup Triggering and Execution): When the re-inspection fails, the controller triggers append cleanup; append cleanup can be performed in at least one of the following ways: (1) Additional scraping at the same point: Keep the slide table at the current axial coordinate X position, control the telescopic actuator to contact again and perform a scraping action; (2) Short stroke sweeping and scraping: Taking the current axial coordinate X as the center, perform short stroke reciprocating sweeping (reciprocating 1 to n times) within the range of X±Δx while keeping the contact force within the preset range, and complete the scraping at the same time; After the additional cleanup is completed, return to steps a to b for a second check.

[0066] d (Closed-loop limit and failure handling): To avoid infinite closed-loop loops, the controller sets a maximum number of additional attempts N_max and / or a maximum closed-loop time T_max for the re-inspection closed loop. When the number of additional attempts reaches N_max or the closed-loop time reaches T_max and the re-inspection still fails, the controller outputs an alarm and records fault information. The fault information includes at least the current position X, the re-inspection area A or confidence level C, the peak value of the contact force, and the number of additional attempts. At the same time, the controller controls the telescopic actuator to retract, causing the ink scraping mechanism to exit the contact surface, and proceeds to step S6 or step S7 (e.g., returning to the standby position or waiting for manual reset).

[0067] e (linked with force control / overpressure protection): During the re-inspection closed loop process, the controller continuously performs constant force / limited force control based on the pressure sensor output; when the contact force or pressure exceeds the preset upper limit F_hi during any scraping or additional cleaning process, the controller immediately controls the telescopic actuator to retract and avoid, and outputs an alarm record. It can also determine that the re-inspection closed loop is a failure and directly transfer to step S6 or step S7, or enter a waiting state and re-inspect after meeting the preset conditions, as an optional strategy.

[0068] In this embodiment, the cleaning effect is verified online through a closed-loop re-inspection, and additional cleaning is automatically performed when the re-inspection fails. This can significantly reduce the probability of missed cleaning, reduce manual intervention, and ensure that the system can safely exit under abnormal operating conditions by setting N_max and / or T_max.

[0069] Optionally, N_max can be taken as 1 to 5 times, T_max as 0.5 to 10 s, Δx as 0.5 to 10 mm, n as 1 to 10 times, and M as 2 to 10 times; A_pass and C_pass can be obtained and adjusted based on camera resolution, detection area size, and trial operation data.

[0070] The foregoing has shown and described the basic principles, main features and advantages of the present invention. Various changes and modifications can be made to the present invention without departing from the spirit and scope thereof, and all such changes and modifications fall within the scope of the present invention as claimed.

Claims

1. An automatic ink cleaning system for a printing press, comprising a mounting base (7), a guide rail (2), a lead screw (3), a slide table (4), a servo motor (5), a reducer (6), a telescopic actuator (1), an ink scraping mechanism (8), a printing plate cylinder (9), a connecting rod (10), an online detection system (11), and a controller, characterized in that: The guide rail (2) is fixedly mounted on the mounting base (7), and the slide (4) is mounted on the guide rail (2) and moves back and forth linearly along the extension direction of the guide rail (2); the lead screw (3) is set along the extension direction of the guide rail (2) and is connected to the slide (4) through the lead screw nut; the servo motor (5) is connected to the lead screw (3) through the reducer (6) to drive the lead screw (3) to rotate and drive the slide (4) to move; the telescopic actuator (1) is fixedly mounted on the slide (4); the ink scraping mechanism (8) is connected to the telescopic end of the telescopic actuator (1); the online detection system (11) is fixedly mounted on the connecting rod (10) and arranged near the printing plate cylinder (9) and facing the predetermined detection area of ​​the printing plate cylinder (9); The controller is electrically connected to the online detection system (11), the servo motor (5), and the telescopic actuator (1), and receives interlock inputs including at least an emergency stop signal, a limit signal, a protective door signal, and an operating mode signal. The controller is configured to: process the image to identify the ink skin area and obtain the corresponding image coordinates; based on the mapping relationship established by at least two known axial reference position calibrations, convert the image coordinates into the axial position coordinates X corresponding to the ink skin area, and output a coordinate validity flag and / or recognition confidence level; only when the coordinate validity flag is valid and / or the recognition confidence level meets a preset threshold, and the interlock input meets the allowable cleaning conditions, control the servo motor (5) to drive the slide (4) in closed-loop operation. Move to the position corresponding to the axial position coordinate X and perform a positioning judgment. The positioning judgment includes at least the absolute value of the position error being less than a preset threshold ε and the holding time being not less than a preset time t. After the positioning judgment is passed, control the telescopic actuator (1) to extend so that the scraping mechanism (8) is against the printing plate cylinder (9) for scraping. After the scraping is completed, control the telescopic actuator (1) to retract and control the slide (4) to return to the standby position. The scraping mechanism (8) includes a connecting frame (17), an adaptive support slider (15), a spring (19), a pressure sensor (18), and a scraper. The connecting frame (17) is connected to the telescopic end of the telescopic actuator (1), and the connecting frame (17) is provided with a tool extending along the contact direction. Guide slide (16); the adaptive support slider (15) slides in cooperation with the guide slide (16), the spring (19) is set between the connecting frame (17) and the adaptive support slider (15), the pressure sensor (18) is located between the spring (19) and the connecting frame (17), and is located on the force transmission path of the squeegee against the printing plate cylinder (9), the pressure sensor (18) is electrically connected to the controller, and is used to output the squeegee contact force or pressure feedback; the controller adjusts the output of the telescopic actuator (1) according to the contact force or pressure feedback, so that the contact force is constant or maintained within the preset range, and controls the telescopic actuator (1) to retract and output an alarm when the contact force or pressure exceeds the preset upper limit F_hi.

2. The automatic ink cleaning system for a printing press according to claim 1, characterized in that: The telescopic actuator (1) is any one of a cylinder, an electric push rod, or an electromagnetic push rod.

3. The automatic ink cleaning system for a printing press according to claim 1, characterized in that: The connecting frame (17) and the telescopic actuator (1) are detachably connected. The detachable connection is any one of the following: threaded connection, clamping ring connection, movable pin connection or quick connector connection.

4. The automatic ink cleaning system for a printing press according to claim 3, characterized in that: The scraper includes a scraper blade (13) and a stainless steel back plate (21). The adaptive support slider (15) is provided with a mounting groove (14). The stainless steel back plate (21) is inserted into the mounting groove (14) and fixed by a locking bolt (20).

5. An automatic ink cleaning system for a printing press according to claim 4, characterized in that: The scraper (13) is made of polyurethane material and is fixed to the stainless steel back plate (21) by casting, hot pressing or bonding; the blade of the scraper (13) is rounded, chamfered or beveled; the hardness of the scraper (13) is 70 to 95 Shore A and the thickness is 1 to 5 mm.

6. An automatic ink cleaning system for a printing press according to any one of claims 1-5, characterized in that: The online inspection system (11) includes an industrial camera and a light source. The industrial camera and the light source are fixedly mounted on the connecting rod (10). The field of view of the industrial camera covers the predetermined inspection area. The light source is used to provide illumination to the predetermined inspection area to enhance the imaging difference between the ink skin and the normal ink film.

7. An automatic ink cleaning system for a printing press according to any one of claims 1-6, characterized in that: It also includes a cleaning block (12) for the cleaning station. The cleaning block (12) is fixed to the inside of the printing press wall panel and has a positioning groove (22). The outer end of the positioning groove (22) is a flared structure. A through hole (23) is provided below the positioning groove (22). The controller is configured to control the slide (4) to enter the cleaning station after scraping is completed, so that the scraper enters the positioning groove (22) and rubs against the inner wall of the positioning groove (22) to remove the residual ink skin on the scraper.

8. A method for automatically cleaning ink scales on a printing press, applied to the automatic ink scale cleaning system on the printing press according to any one of claims 1 to 7, characterized in that, Includes the following steps: S1, The controller obtains the interlock input and performs an interlock determination; S2, the online detection system (11) collects images of the predetermined detection area, and the controller performs ink skin recognition to obtain the coordinates of the ink skin area image and generates a valid coordinate mark and / or recognition confidence; S3, the controller converts the image coordinates into axial position coordinates X based on the mapping relationship established by at least two known axial reference positions; S4, when the coordinate valid flag is valid and the interlock meets the allowed cleaning conditions, control the servo motor (5) to drive the slide (4) to move in a closed loop to X and perform the position determination. The position determination includes at least the absolute value of the position error being less than ε and the holding time being not less than t. S5, after the positioning judgment is passed, the telescopic actuator (1) is controlled to extend so that the scraper is against the printing plate cylinder (9) for scraping, and the output of the telescopic actuator (1) is adjusted according to the feedback of the pressure sensor (18) so that the contact force is constant or maintained within the preset range; when the contact force or pressure exceeds the preset upper limit F_hi, the telescopic actuator (1) is controlled to retract and an alarm is triggered. S6, after scraping is completed, control the telescopic actuator (1) to retract and control the slide (4) to return to the standby position; S7. If any of the above steps result in failure to reach the target position, interlock failure, limit triggering, excessive contact force / pressure, abnormal detection signal, or abnormal communication, an abnormality shall be handled. The abnormality handling shall include at least stopping the movement of the slide (4) and controlling the telescopic actuator (1) to retract and exit the contact surface, while outputting an alarm and / or recording fault information.

9. The method according to claim 8, characterized in that, Before or after step S6, the controller controls the slide (4) to enter the cleaning station, so that the scraper enters the positioning groove (22) of the cleaning block (12) and rubs against the inner wall of the positioning groove (22) to remove residual ink on the scraper.

Images