Intelligent paper printing quality detection system and method thereof

Abstract

The invention relates to the technical field of machine vision detection, and discloses an intelligent paper printing quality detection system and a method thereof.The intelligent paper printing quality detection system comprises a winding drum conveying mechanism used for conveying roll paper, and the winding drum conveying mechanism is provided with at least one synchronous rotating roller rotating synchronously with the roll paper; the position synchronization module comprises a rotary encoder coaxially connected with the synchronous rotating roller, and the rotary encoder is used for generating a position synchronization signal in direct proportion to the conveying distance of the roll paper; the image acquisition module comprises a camera arranged above a conveying path of the roll paper; and the central processing module is electrically connected with the position synchronization module and the image acquisition module. By adopting a hardware triggering mechanism based on a physical distance and double-encoder differential measurement, the problem of image geometric distortion caused by conveying speed fluctuation is solved, and synchronous quantization of the physical state of the roll paper in a detection section is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of machine vision detection, and in particular to an intelligent paper printing quality detection system and method thereof. Background Art

[0002] In the production and processing of continuous materials such as roll paper and film, online machine vision inspection systems are often used to monitor printing defects on the material surface in real time to ensure product quality. These systems typically use industrial cameras, light sources, and other image acquisition equipment installed on the production line to continuously capture images of the moving material surface. Computers then process and analyze these images to identify various defects such as missing prints, dirty spots, color differences, and misregistering.

[0003] In practical applications, existing machine vision inspection technologies face a series of technical challenges stemming from the physical characteristics of continuous material conveying. During high-speed conveyance, the linear speed of web materials often fluctuates due to starts and stops, acceleration and deceleration, or mechanical disturbances in the equipment. Some existing systems use a single rotary encoder to synchronize camera acquisition. However, due to the inherent elasticity of the web paper and the potential for slight slippage between the roller and the paper, the displacement measured by a single encoder cannot accurately represent the actual displacement of the paper in the image acquisition area. When the conveying speed changes, if the image acquisition trigger interval does not strictly correspond to the physical distance the paper moves, the captured image will suffer geometric distortion due to stretching or compression in the direction of motion. This geometric inconsistency directly impacts the stability and accuracy of subsequent defect detection algorithms based on image comparison using standard templates.

[0004] Furthermore, existing inspection systems typically only identify the presence, location, and form of defects but fail to provide in-depth information about their causes. For example, when detecting a defect where printed content is blurred, the system cannot determine whether the root cause is a mechanical issue with the printing unit or a momentary jitter caused by a dramatic fluctuation in paper tension within the inspection section. This limitation of only reporting the defect without being able to diagnose its physical cause limits the system's role in assisting with production process optimization. Quality control remains limited to the post-process rejection of defective products, making it difficult to implement feed-forward process adjustments.

[0005] At the same time, existing technologies also have shortcomings when it comes to locating defects. In addition to longitudinal movement, web materials often exhibit irregular lateral swinging during transport, known as "snaking." If the system fails to track and compensate for this lateral deviation in real time, the recorded defect coordinates are only local coordinates relative to the camera's field of view, rather than absolute coordinates across the entire web width. This incomplete positioning information makes it difficult to automate and accurately remove defects based on their location in subsequent processes (such as slitting and rewinding), potentially increasing scrap rates or requiring additional manual intervention. Summary of the Invention

[0006] In response to the shortcomings of the existing technology, the present invention provides an intelligent paper printing quality inspection system and method, which solves the problem in the existing web printing quality inspection technology that it is difficult to accurately locate defects due to the combined influence of factors such as conveying speed fluctuations, changes in the physical state of the material, and lateral position offset, and it is impossible to effectively associate visual defects with their physical causes.

[0007] To achieve the above objectives, the present invention is implemented through the following technical solutions: an intelligent paper printing quality detection system and method thereof, comprising:

[0008] A roll conveying mechanism for conveying roll paper, wherein the roll conveying mechanism is provided with at least one synchronously rotating roller that rotates synchronously with the roll paper;

[0009] a position synchronization module, comprising a rotary encoder coaxially connected to the synchronously rotating roller, the rotary encoder being configured to generate a position synchronization signal proportional to a conveying distance of the paper roll;

[0010] An image acquisition module, comprising a camera arranged above the roll paper conveying path;

[0011] A central processing module is electrically connected to the position synchronization module and the image acquisition module, and is configured to:

[0012] receiving the position synchronization signal;

[0013] Based on the position synchronization signal, after the roll paper has conveyed a preset distance, a hardware trigger instruction is sent to the camera;

[0014] Responding to the hardware trigger instruction, acquiring a real-time image captured by the camera;

[0015] Comparing and analyzing the real-time image with a preset standard template to determine the printing quality of the roll paper;

[0016] a transverse position sensing unit, configured to monitor the transverse deviation of the paper roll in the width direction in real time and send transverse position data to the central processing module;

[0017] The defective product processing module is electrically connected to the central processing module and is used to execute an alarm, mark the roll paper, or record the defect coordinates according to the judgment result.

[0018] Preferably, the roll conveying mechanism is further provided with a second synchronously rotating roller, and the second synchronously rotating roller is located upstream or downstream of the synchronously rotating roller;

[0019] The position synchronization module further includes a second rotary encoder coaxially connected to the second synchronous rotating roller, for generating a second position synchronization signal;

[0020] The central processing module is further configured to determine a material physical state of the web between the two synchronously rotating rollers by comparing the position synchronization signal and the second position synchronization signal.

[0021] Preferably, the central processing module is further configured to: perform correlation analysis on the printing quality defect information and the physical state of the material to assist in determining the root cause of the defect.

[0022] Preferably, the central processing module is further configured to: fuse the longitudinal position information provided by the rotary encoder, the lateral position data provided by the lateral position sensing unit, and the determined defect information to generate a three-dimensional defect map for the defect on the entire roll of paper.

[0023] Preferably, the central processing module is further configured to: learn the location patterns of periodic defects based on historical defect information, and dynamically adjust image acquisition or comparison analysis strategies in subsequent detection processes.

[0024] Preferably, the central processing module performs the comparison analysis by executing at least one algorithm selected from template matching, optical character recognition, barcode / QR code reading, or BLOB analysis.

[0025] Preferably, the preset conveying distance corresponds to the physical length of one or more complete printing repeating units on the roll paper.

[0026] A method for detecting printing quality of intelligent paper includes the following steps:

[0027] Conveying step: conveying the roll paper through the roll conveying mechanism, and causing the synchronously rotating roller that rotates synchronously with the roll paper to drive the rotary encoder to rotate;

[0028] Position synchronization monitoring step: generating a position synchronization signal proportional to the conveying distance of the roll paper by the rotary encoder;

[0029] A position-based triggering acquisition step: when the position synchronization signal is detected to indicate that the roll paper has been transported a preset distance, triggering a camera to acquire a real-time image;

[0030] Comparison and analysis step: comparing and analyzing the real-time image with a preset standard template to determine the printing quality of the roll paper.

[0031] The present invention provides an intelligent paper printing quality detection system and method thereof. It has the following beneficial effects:

[0032] 1. This invention utilizes a synchronously rotating roller that rotates synchronously with the paper roll and a coaxially connected rotary encoder to generate a position synchronization signal proportional to the paper transport distance. This signal triggers the camera at a preset distance for image acquisition. This triggering mechanism, based on physical distance rather than time, ensures that each captured image frame has a constant geometric dimension in the paper transport direction, unaffected by fluctuations in the roll transport mechanism's speed. This provides input data with consistent geometric dimensions for subsequent image comparison and analysis based on a standard template, ensuring accurate print quality inspection.

[0033] 2. The present invention constructs a dual-channel differential measurement structure by placing synchronously rotating rollers and corresponding rotary encoders upstream and downstream of the detection area. By comparing the signals generated by the two rotary encoders within the same time window, the central processing module can calculate the physical material state of the web in the section between the two rollers, such as strain or slip. When a print quality defect is detected, the system correlates the defect information with the material physical state data at that moment. This correlation provides a new data dimension for analyzing the cause of the defect, making it possible to distinguish defects arising from the printing process itself from defects arising from physical conveying processes such as material tension fluctuations.

[0034] 3. By integrating longitudinal position information from the position synchronization module, transverse position data from the transverse position sensing unit, and defect coordinates identified within the image, this invention generates unique three-dimensional defect coordinates for each detected defect within the entire web coordinate system. This process transforms discrete defect events into a structured, digital three-dimensional defect map containing precise spatial location information. This map provides precise positioning for automated rejection operations in subsequent processes and provides comprehensive data support for quality assessment and traceability of the entire web. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1This is a system architecture diagram of the present invention. DETAILED DESCRIPTION

[0036] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the present specification. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0037] Please see the attached Figure 1 , an embodiment of the present invention provides an intelligent paper printing quality detection system and method thereof, including:

[0038] A roll conveying mechanism for conveying roll paper, wherein the roll conveying mechanism is provided with at least one synchronously rotating roller that rotates synchronously with the roll paper;

[0039] In this embodiment, the roll conveying mechanism serving as the physical basis and measurement reference of the present invention is described in detail.

[0040] The function of the roll conveying mechanism is to provide a continuous and mechanically controllable conveying channel for the roll paper to be inspected, and to provide the necessary mechanical interface and stable working environment for subsequent machine vision inspection and multi-dimensional physical state perception.

[0041] In a specific embodiment, the roll conveying mechanism includes an unwinding unit, a plurality of guide rollers, at least two key synchronously rotating rollers, and a rewinding unit.

[0042] The unwinding unit is used to carry a whole roll of paper to be inspected and may be integrated with a tension control system, such as a magnetic powder brake or a servo motor, to provide stable discharge tension.

[0043] The guide roller is used to guide the paper conveying path to ensure that the paper is in a flat state.

[0044] The number and layout of the guide rollers can be adjusted according to the specific space and process requirements of the production line.

[0045] The key point of this embodiment is that a front synchronously rotating roller (hereinafter referred to as front roller A) and a rear synchronously rotating roller (hereinafter referred to as rear roller B) are respectively installed along the conveying path of the roll conveyor mechanism, specifically upstream and downstream of the detection area for performing image acquisition. The arrangement of these two rollers is the key physical structure for realizing the multi-dimensional state sensing described in this invention.

[0046] The front roller A and rear roller B can be active drive rollers or passive follower rollers. Their common characteristic is that their roller surfaces maintain close, non-slip contact with the surface of the paper roll. To achieve this, in a preferred embodiment, the surfaces of the front roller A and rear roller B can be coated with a high-friction material, such as polyurethane or nitrile rubber, to ensure a strict proportional relationship between the roller angular velocity and the paper's linear velocity during changes in paper tension or speed increases or decreases.

[0047] The rear roller B is physically located adjacent to the image acquisition module's location. This layout minimizes the physical distance between the position synchronization signal source used to trigger image acquisition and the actual image acquisition point, thereby reducing measurement errors that may be introduced by paper deformation between the two.

[0048] The diameters of the front roller A and rear roller B, denoted as D_A and D_B, are known parameters that have been precisely machined and measured. These two diameters serve as the basis for system calibration, subsequently converting roller angular displacement into precise linear displacement of the paper.

[0049] The arrangement of these two rollers provides the necessary mechanical mounting interface for the dual-encoder differential measurement solution described in this invention. Specifically, the rotating shaft of rotary encoder A is rigidly connected coaxially with the rotating shaft of the leading roller A; the rotating shaft of rotary encoder B is rigidly connected coaxially with the rotating shaft of the trailing roller B. This structure allows the linear displacement of paper passing through points A and B on the conveyor path to be directly and highly fidelity converted into digital angular displacement signals generated by two independent rotary encoders.

[0050] Therefore, the roll conveyor mechanism not only performs traditional material conveying functions but, more importantly, through the specific configuration of front rollers A and rear rollers B, establishes a distributed differential measurement benchmark capable of reflecting the physical deformation of the paper within the conveying section. When the paper stretches or compresses due to tension changes between points A and B, even if the overall conveying speed of the paper remains constant, the instantaneous linear velocity of the paper passing through points A and B will vary slightly.

[0051] This structure enables the subsequent central processing module to calculate the strain state of the paper in the detection area in real time and quantitatively by analyzing the signal difference between the two encoders, thereby converting a purely mechanical conveying problem into a physical parameter that can be accurately measured.

[0052] a position synchronization module, comprising a rotary encoder coaxially connected to the synchronously rotating roller, the rotary encoder being configured to generate a position synchronization signal proportional to a conveying distance of the paper roll;

[0053] In this embodiment, the position synchronization module, which is the core of the data acquisition and synchronization control of the system of the present invention, is described in detail.

[0054] The position synchronization module accurately converts the macroscopic physical movement of the paper web during transport into standardized digital position signals for use by the central processing module. This module is the technical prerequisite for implementing a physical distance-based image acquisition trigger mechanism and for quantitative diagnosis of the material's physical condition.

[0055] In a specific embodiment, the position synchronization module includes at least one rotary encoder. In a preferred embodiment of the present invention, to achieve more functions, the module includes two high-precision rotary encoders, hereinafter respectively defined as Encoder A and Encoder B.

[0056] The mechanical mounting method for encoders A and B has been explained in the description of the roll conveyor mechanism above: their rotating shafts are rigidly connected coaxially with the rotating shafts of the leading roller A and trailing roller B, respectively. The encoders can be incremental or absolute encoders. In a preferred embodiment, an incremental quadrature encoder is used because it can provide high-frequency A / B phase pulse signals at high rotation speeds, facilitating high-resolution position tracking and direction determination.

[0057] The electrical outputs of encoders A and B are electrically connected to the high-speed counter interface of the central processing module. During system operation, as the front roller A and the rear roller B rotate, encoders A and B continuously generate pulse trains proportional to their respective angular displacements.

[0058] Generation and functional division of position synchronization signals:

[0059] Encoder B, due to its physical proximity to the image acquisition module, generates a pulse signal that is defined as the master synchronization signal. The core function of this master synchronization signal is to provide a precise time reference for image acquisition based on physical distance. Specifically, the central processing module continuously counts the pulses from encoder B. This count directly reflects the linear distance the paper has moved at the detection point.

[0060] The pulse signal generated by the encoder A is defined as an auxiliary synchronization signal. This auxiliary synchronization signal is used in conjunction with the main synchronization signal, and its core function is to achieve differential measurement of the physical deformation of the paper web within the detection section.

[0061] Signal processing and parameter calibration:

[0062] Before the system is running, the position synchronization module needs to be calibrated. The calibration content includes:

[0063] Encoder resolution: The number of pulses generated by encoder A and encoder B per revolution, recorded as R A and R B .

[0064] Roller diameter: The exact diameter of roller A and roller B linked to the encoder, recorded as D A and D B .

[0065] Based on these calibration parameters, the central processing module can convert the received discrete pulse number into a continuous physical distance. This conversion process is the basis for all subsequent position-based applications.

[0066] Image trigger mechanism based on the main synchronization signal:

[0067] The position synchronization module works in conjunction with the central processing module to address image distortion caused by conveyor speed fluctuations. During system detection, a hardware counter within the central processing module accumulates pulses from encoder B. When, and only when, the counter reaches the preset Nrep value, the central processing module immediately sends a hardware trigger command to the image acquisition module via the hardware I / O port. Once triggered, the counter is reset and the next counting cycle begins. This mechanism ensures that the trigger moment for image acquisition is strictly determined by the physical distance the paper has traveled, rather than by time, thereby ensuring that the scale of the captured image remains constant in the direction of motion.

[0068] Material status diagnosis based on dual-channel synchronous signals:

[0069] In this embodiment, the position synchronization module enables quantitative diagnosis of the material's physical state by providing two independent, spatially separated position signals. Therefore, the module's functionality goes beyond simple position determination. Through its dual-channel differential measurement architecture, it provides the system with a sensing capability capable of perceiving and quantifying the material's mechanical properties. This capability is the technical foundation for the defect-process state correlation analysis described in this invention.

[0070] An image acquisition module, comprising a camera arranged above the roll paper conveying path;

[0071] In this embodiment, the image acquisition module, which is the source of visual information acquisition of the system of the present invention, is described in detail.

[0072] The image acquisition module's function is to instantly and highly fidelity convert the physical printed pattern on the surface of the paper web, while in high-speed motion, into digital image data for analysis by the central processing module. The core technical challenge is ensuring the clarity and geometric consistency of the captured image despite fluctuations in conveyor speed.

[0073] In a specific embodiment, the image acquisition module mainly includes a camera, a matching optical lens, and a dedicated lighting system.

[0074] The camera is preferably a high-speed industrial camera. Depending on the characteristics of the object to be inspected, either an area scan camera or a line scan camera can be used. For example, a line scan camera is suitable for applications with wide formats or requiring extremely high resolution; an area scan camera is also suitable for conventional labels or small-format printed materials. A key feature of the camera is that it must support external hardware triggering.

[0075] The camera transmits image data to the central processing module via a data interface (e.g., GigEVision, USB3Vision, or CameraLink). More importantly, the camera is also electrically connected to the central processing module's digital input / output (I / O) port via a dedicated digital I / O port. This connection is specifically used to receive hardware trigger commands sent by the central processing module.

[0076] The optical lens is mounted on the camera, and its selection needs to match the sensor size of the camera and the required field of view (FOV) to ensure that all key areas of the printed product to be inspected can be fully covered.

[0077] The dedicated lighting system provides a uniform, stable, and flicker-free illumination environment for the inspection area, eliminating the impact of ambient light variations on image quality and highlighting printing defects. In a preferred embodiment, a linear LED light source arranged perpendicular to the paper's direction of motion can be used to create a uniform linear illumination area, particularly suitable for use with line scan cameras.

[0078] The image acquisition module is physically mounted on the frame of the roll conveyor mechanism, with its optical axis perpendicular to the surface of the paper roll being conveyed. Its installation position, in the conveying direction, is adjacent to the rear roller B to minimize the physical distance between the position synchronization signal source and the image acquisition point.

[0079] Acquisition workflow based on external hardware trigger:

[0080] The working mode of the image acquisition module is set to external hardware trigger mode. In this mode, the camera itself does not actively perform image acquisition, but is in a waiting state.

[0081] The workflow is as follows:

[0082] The central processing module counts according to the pulse signal from the encoder B of the position synchronization module.

[0083] When the pulse count reaches the preset threshold Nrep, indicating that the paper has accurately moved the preset distance Lrep, the central processing module immediately sends a level transition signal (e.g., a rising or falling edge) through its digital I / O port to the corresponding digital I / O port of the camera. Upon detecting this hardware trigger signal, the electronic circuitry within the camera immediately initiates an exposure-readout cycle, completing the acquisition of a single frame. The exposure time (shutter speed) must be set based on the maximum paper transport speed to avoid motion blur.

[0084] The acquired digital image data is transmitted to the memory of the central processing module through the data interface, waiting for subsequent processing.

[0085] Through this external hardware-triggered mechanism, the image capture moment is strictly tied to the physical distance traveled by the paper. This mechanism removes the time factor from the determining condition for acquisition triggering, ensuring that even if the linear speed of the web conveyor fluctuates during acceleration, deceleration, or operation, the geometric dimensions of the physical content contained in each captured image frame remain constant in the direction of motion. This mechanism directly addresses the issue of image stretching or compression caused by speed variations, providing geometrically consistent, high-quality input images for subsequent fixed-template-based image comparison and analysis.

[0086] A central processing module is electrically connected to the position synchronization module and the image acquisition module, and is configured to:

[0087] receiving the position synchronization signal;

[0088] Based on the position synchronization signal, after the roll paper has conveyed a preset distance, a hardware trigger instruction is sent to the camera;

[0089] Responding to the hardware trigger instruction, acquiring a real-time image captured by the camera;

[0090] Comparing and analyzing the real-time image with a preset standard template to determine the printing quality of the roll paper;

[0091] a transverse position sensing unit, configured to monitor the transverse deviation of the paper roll in the width direction in real time and send transverse position data to the central processing module;

[0092] In this embodiment, the lateral position sensing unit as a part of the system of the present invention for achieving high-precision positioning is described in detail.

[0093] The lateral position sensing unit is designed to address the lateral position uncertainty commonly found in high-speed web transport, often referred to as "snaking." It provides the system with a real-time, quantitative data input to compensate for this lateral deviation.

[0094] The technical purpose of setting up this unit is to ensure that the subsequent image processing algorithm can act on the precise printed content area, avoiding the region of interest (ROI) from deviating from the target due to lateral drift of the paper, thereby preventing missed detection or misjudgment.

[0095] In a specific embodiment, the transverse position sensing unit includes one or more sensors, which are physically fixed on the frame of the roll conveying mechanism, and the detection axis thereof is perpendicular to the conveying direction of the paper.

[0096] In a preferred embodiment, the transverse position sensing unit may be a laser edge sensor. The sensor emits a laser beam toward one edge of the paper web and receives reflected or blocked light signals to accurately calculate the position of the paper edge relative to a fixed reference point on the sensor itself.

[0097] In another optional embodiment, the lateral position sensing unit may also be a line scan camera, which is arranged perpendicular to the paper's direction of movement and images the paper edge and performs image processing to determine the precise pixel coordinates of the edge line, thereby converting the coordinates into the physical position.

[0098] Regardless of the specific sensor type employed, the lateral position sensing unit ultimately outputs an electrical signal proportional to the lateral offset of the paper. This signal, defined as lateral position data, is transmitted in real time, continuously, or discretely at high frequency to the corresponding data acquisition interface of the central processing module.

[0099] Application and processing flow of horizontal position data:

[0100] The lateral position data generated by the lateral position sensing unit is mainly used in two core technical processes in the central processing module:

[0101] First, it's used for dynamic correction of regions of interest (ROIs) in image processing. When the central processing module acquires a new real-time image from the image acquisition module, before executing the defect recognition algorithm, it first reads the lateral position data corresponding to the moment the image was acquired. This data value represents the lateral offset of the paper relative to a reference zero point at that moment. The central processing module then dynamically adjusts the lateral starting coordinates of the preset standard ROI based on this offset. This operation ensures that the analysis window remains precisely locked on the valid printed pattern, regardless of how the paper moves.

[0102] Second, it is used to construct the three-dimensional spatial coordinates of the defect. When a defect is identified at time t_defect, the central processing module not only records the defect's coordinates within the image but also locks the lateral position data at that moment. This data is used as one of the key inputs to calculate the defect's absolute lateral coordinates within the entire web coordinate system.

[0103] Therefore, the lateral position sensing unit enables the system to cope with dynamic changes in the lateral position of the web material by providing accurate lateral position data, which is a necessary technical prerequisite for achieving subsequent high-precision defect positioning and three-dimensional defect map construction.

[0104] a defective product processing module, electrically connected to the central processing module, and configured to generate an alarm, mark the roll paper, or record defect coordinates according to the judgment result;

[0105] In this embodiment, the defective product processing module serving as the physical execution terminal of the system of the present invention is described in detail.

[0106] The defective product processing module responds to execution instructions from the central processing module and performs real-time, physical, or digital processing on detected areas of defective printed matter. The technical purpose of this module is to transform upstream inspection results into direct intervention on physical products or production data, thereby achieving a closed-loop quality control system.

[0107] In a specific embodiment, the defective product processing module may include one or more execution devices, which are electrically connected to the digital output port of the central processing module through corresponding driving circuits.

[0108] This module can include an audible and visual alarm device to provide immediate feedback to operators. When the central processing module determines that the type or severity of a defect exceeds a preset threshold, it outputs a continuous or pulsed drive signal to the specific I / O port connected to the audible and visual alarm device, triggering the alarm to emit an audible or visual signal to alert on-site personnel.

[0109] The module may also include a physical marking device for physically marking the paper web. In a preferred embodiment, the physical marking device may be a high-speed inkjet valve. The inkjet valve is physically mounted on the frame of the web transport mechanism, downstream of the image acquisition module.

[0110] Precise marking execution process based on position delay:

[0111] Since there is a fixed physical distance between the physical marking device and the image acquisition module, the execution of the marking action must be carried out through accurate position delay calculation. The execution process is as follows:

[0112] The central processing module continuously monitors the pulse count of the main synchronization signal from encoder B. When and only when the total value reaches P_marker_trigger, the module immediately sends an instantaneous execution command signal to the physical marking device through its digital output port to drive the inkjet valve to complete an inkjet action.

[0113] This position delay-based triggering mechanism ensures that the physical mark can be accurately applied to the physical position corresponding to the detected defect without being affected by changes in conveying speed.

[0114] Digital processing and recording:

[0115] In addition to physical disposal, the defective product processing module also performs digital processing. When the central processing module identifies a defect, regardless of whether it requires physical marking, it will record the defect coordinates.

[0116] This operation writes the complete information of the defect, especially its three-dimensional coordinates in the coordinate system of the entire roll of material, together with its type, size, severity level, and associated material strain / slip index information into a data file or sends it to a database.

[0117] The structured data generated by this operation, known as a 3D defect map or quality roll map, constitutes a digital defective product processing method of the present invention. This map provides an accurate basis for rejecting waste in subsequent processes such as slitting and rewinding, making it possible to automatically reject defective product segments.

[0118] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. Intelligent paper printing quality detection system and method, characterized in that: include: A roll conveying mechanism for conveying roll paper, wherein the roll conveying mechanism is provided with at least one synchronously rotating roller that rotates synchronously with the roll paper; a position synchronization module, comprising a rotary encoder coaxially connected to the synchronously rotating roller, the rotary encoder being configured to generate a position synchronization signal proportional to a conveying distance of the paper roll; An image acquisition module, comprising a camera arranged above the roll paper conveying path; A central processing module is electrically connected to the position synchronization module and the image acquisition module, and is configured to: receiving the position synchronization signal; Based on the position synchronization signal, after the roll paper has conveyed a preset distance, a hardware trigger instruction is sent to the camera; Responding to the hardware trigger instruction, acquiring a real-time image captured by the camera; Comparing and analyzing the real-time image with a preset standard template to determine the printing quality of the roll paper; a transverse position sensing unit, configured to monitor the transverse deviation of the paper roll in the width direction in real time and send transverse position data to the central processing module; The defective product processing module is electrically connected to the central processing module and is used to execute an alarm, mark the roll paper, or record the defect coordinates according to the judgment result.

2. The intelligent paper printing quality detection system and method according to claim 1, characterized in that: The roll conveying mechanism is further provided with a second synchronously rotating roller, which is located upstream or downstream of the synchronously rotating roller; The position synchronization module further includes a second rotary encoder coaxially connected to the second synchronous rotating roller, for generating a second position synchronization signal; The central processing module is further configured to determine a material physical state of the web between the two synchronously rotating rollers by comparing the position synchronization signal and the second position synchronization signal.

3. The intelligent paper printing quality detection system and method according to claim 2, characterized in that: The central processing module is further configured to: perform correlation analysis on the printing quality defect information and the physical state of the material to assist in determining the root cause of the defect.

4. The intelligent paper printing quality detection system and method according to claim 1, characterized in that: The central processing module is further configured to fuse the longitudinal position information provided by the rotary encoder, the lateral position data provided by the lateral position sensing unit, and the determined defect information to generate a three-dimensional defect map for the defect on the entire roll of paper.

5. The intelligent paper printing quality detection system and method according to claim 1, characterized in that: The central processing module is further configured to learn the location patterns of periodic defects based on historical defect information and dynamically adjust image acquisition or comparison analysis strategies in subsequent inspection processes.

6. The intelligent paper printing quality detection system and method according to claim 1, characterized in that: The central processing module performs the comparison analysis by executing at least one algorithm selected from the group consisting of template matching, optical character recognition, barcode / QR code reading, and BLOB analysis.

7. The intelligent paper printing quality detection system and method according to claim 1, characterized in that: The preset conveying distance corresponds to the physical length of one or more complete printing repeating units on the web.

8. An intelligent paper printing quality detection method, used in the intelligent paper printing quality detection system and method according to any one of claims 1 to 7, characterized in that: The following steps are involved: Conveying step: conveying the roll paper through the roll conveying mechanism, and causing the synchronously rotating roller that rotates synchronously with the roll paper to drive the rotary encoder to rotate; Position synchronization monitoring step: generating a position synchronization signal proportional to the conveying distance of the roll paper by the rotary encoder; A position-based triggering acquisition step: when the position synchronization signal is detected to indicate that the roll paper has been transported a preset distance, triggering a camera to acquire a real-time image; Comparison and analysis step: comparing and analyzing the real-time image with a preset standard template to determine the printing quality of the roll paper.

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