A water transfer printing method for substrates that does not require primer spraying

Abstract

This invention relates to the field of thin-film water transfer printing technology, and discloses a water transfer printing method for substrates that does not require primer spraying. The method includes: system setup, system calibration, 3D volume modeling, 3D volume pattern construction, 3D entity sampling, comparison of 3D entities with 3D volume models, water transfer film pattern simulation, water transfer film printing, water transfer, film curing, and mass production. This substrate-free water transfer printing method, through an equipment system and industrial camera, achieves uniform movement and real-time trajectory acquisition of the substrate, facilitating analysis and comparison of the travel path, selection of the optimal path for mass production, and optimal uniform speed for mass production. Through the combination of software simulation and hardware equipment, it can solve problems in existing water transfer printing technologies such as cumbersome processes, inaccurate positioning, difficulty in customization, high cost, environmental pollution, and low efficiency. Furthermore, the use of solvent-based adhesives enhances the adhesion of the water transfer ink to the substrate, reducing the cost and environmental pollution associated with pre-coating the substrate with primer.

Description

Technical Field

[0001] This invention relates to the field of thin-film water transfer printing technology, specifically to a water transfer printing method for substrates that does not require primer spraying. Background Technology

[0002] Currently, with the increasing demands of people for product packaging and decoration, water transfer printing is becoming more and more widely used, and has been applied to fields such as automotive supplies, electronic products, household goods, daily necessities, and interior architecture.

[0003] Water transfer printing is a well-known industrial technique used to transfer colored ink from a thin film to the surface of an object, enabling surface coloring and patterning. It primarily utilizes water pressure to hydrolyze the polymer in a transfer paper / plastic film bearing a colored pattern, which then adheres to the object to achieve the patterned effect. Objects often possess various shapes, some protruding, some recessed, some hollow, some wrinkled, etc. These unusual shapes are difficult to completely cover with traditional spray painting techniques, as blind spots exist, resulting in less aesthetically pleasing and practical finished products. However, with water transfer printing, the fluidity of water allows the ink to penetrate even these unusual shapes, achieving overall patterning and aesthetic appeal.

[0004] Traditional water transfer printing is a well-known technique for transferring color images onto the surface of three-dimensional objects. First, an ink image is printed onto a polyvinyl alcohol (PVA) film using a traditional inkjet printer. This PVA film carrying the ink image is then placed on water. A chemical activator is sprayed onto the PVA film to soften it, making it easier to stretch and activating it. The object to be patterned is then slowly immersed in the water. Upon contact with the object, the floating film stretches, wraps around the object's surface, and adheres. Current water transfer printing uses repeatable color texture patterns, thus eliminating the need for precise positioning. However, during this process, the color ink on the PVA film moves with the film. For intricate and complex patterns, it is difficult to align with the surface of the object being patterned, leading to water transfer deviations, distorted ink transfer, or pattern tearing. Furthermore, due to these defects, customized water transfer printing is difficult to achieve. Additionally, to ensure strong adhesion, a primer needs to be sprayed onto the object surface. This primer is expensive, increasing costs, adding to production processes, and causing environmental pollution.

[0005] Therefore, existing water transfer printing technology needs further improvement to address the aforementioned issues. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of existing water transfer printing technology, such as the inability to achieve customization, low efficiency, complex process, and high cost. It provides a water transfer printing method that eliminates the need for a primer on the substrate, which can solve the problems of cumbersome process, inaccurate positioning, difficulty in customization, high cost, environmental pollution, and low efficiency in existing water transfer printing technology.

[0007] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0008] A water transfer printing method for substrates that does not require primer spraying, the water transfer printing method comprising the following steps:

[0009] Step 1: System Setup

[0010] A. Setting up the operating equipment:

[0011] A device support is selected, and a sliding mechanism is installed on the device support. A robotic arm is installed on the sliding mechanism. The sliding mechanism is used to drive the robotic arm to slide. The robotic arm is used to grasp and move the object to be printed. A water tank is provided below the device support. The water tank is used to hold water and transfer film. An industrial camera assembly is installed around the water tank. The industrial camera assembly is equipped with a camera bracket and an industrial camera. The camera bracket is selected as a three-dimensional movement and rotation bracket. The camera bracket is used to rotate and move the industrial camera.

[0012] B. Operating System Setup:

[0013] A controller, a computer, and water transfer printing operation software are selected. The computer is equipped with the water transfer printing operation software, which is used to perform water transfer printing on the substrate. The computer is externally connected to the controller, which is electrically connected to the power terminals of the sliding mechanism, the robot arm, and the industrial camera assembly.

[0014] Step 2: System Calibration

[0015] Based on the system in step one, the standard substrate is moved to the transfer area of ​​the water tank and slowly and uniformly lowered to the water surface of the tank. The industrial camera will collect the movement trajectory and movement status of the standard substrate in real time and feed back the collected image information to the computer to form a preliminary operation path.

[0016] Step 3: 3D volume modeling

[0017] Select the object to be printed, use 3D modeling software to create a 3D model of the object to be printed, and calculate the ratio between the modeled 3D object and the actual object to be printed.

[0018] Step 4: 3D Volume Pattern Construction

[0019] Based on the modeling in step three, 3D modeling software is used to model the 3D body pattern, draw the 3D body pattern, and assemble the 3D body pattern with the 3D body to be printed.

[0020] Step 5: 3D Entity Sampling

[0021] Based on the calibration system in step two, a robotic arm is selected to grasp the object to be printed and slowly and uniformly lower it to the water surface in the water tank. An industrial camera captures images in real time and feeds the captured image information back to the computer to form a processing operation path.

[0022] Step Six: Comparison of 3D Entity and 3D Volume Model

[0023] Based on the 3D entity sampling in step five, the industrial camera performs imaging scanning on the 3D entity, transmits the acquired image to the computer, and compares the acquired image with the 3D model of the 3D entity to be printed to form an image acquisition path.

[0024] Step 7: Simulation of Water Transfer Film Pattern

[0025] Based on the 3D volume pattern from step four, a planar mapping method is used to perform planar mapping of the surface of the 3D volume pattern. Unitized pixel decomposition is used to perform one-to-one planar mapping. Unitized pixels can be superimposed and overlapped. The number of overlaps and the overlap area of ​​each unitized pixel are calculated.

[0026] Step 8: Water Transfer Film Printing

[0027] Based on the water transfer film pattern in step seven, and using the proportion from step three, color ink is printed on polyvinyl alcohol resin using an ink printer. The overlapping areas and the number of overlaps are adjusted accordingly with ink. After the water transfer film is printed and the ink dries, a solvent-based adhesive is applied to the ink layer.

[0028] Step Nine: Water Transfer Printing

[0029] Based on the water transfer film in step eight, place it on the water surface of the water tank, fix the water transfer film, spray an activator on the water transfer film, and based on the processing and operation path in step five, gradually bring the object to be printed into contact with the water transfer film and adhere it to the object to be printed.

[0030] Step 10: Film Formation and Curing

[0031] Based on the water transfer printing substrate from step nine, it is dried, and the water transfer printing substrate is dried and cured in a suitable temperature environment of 65-75℃.

[0032] Preferably, the activator in step nine is a plasticizer dissolved in a volatile solvent; under the action of the plasticizer, the PVA resin and ink quickly become soft and viscous, forming a thin and viscous sheet on the water surface. When the substrate is placed in the water and comes into contact with the viscous sheet, the ink and PVA resin film adhere to the substrate, but this adhesion is not very strong.

[0033] Preferably, the solvent-based adhesive used in step eight is selected from polyurethane resin or acrylic resin.

[0034] Preferably, the dry base thickness of the solvent-based adhesive is 10–60 μm.

[0035] Preferably, the dry base thickness of the solvent-based adhesive is 30–40 μm.

[0036] Preferably, the water transfer printing method includes the following steps:

[0037] Step 1: System Setup

[0038] A. Setting up the operating equipment:

[0039] A device support is selected, which is a square metal support. A sliding mechanism is installed on the device support, which is horizontally mounted on the device support. The sliding mechanism is equipped with a slider, a slide rail, and a drive motor. The drive motor drives the slider to slide back and forth on the slide rail, allowing for positioning and movement at any time. A robotic arm is installed on the slider. The robotic arm is raised, lowered, and rotated by a robotic arm motor and a moving bracket. The robotic arm is equipped with a gripping suction cup and a gripping hand for gripping the substrate. A water tank is located below the device support to hold water and transfer film. An industrial camera assembly is installed around the water tank. The industrial camera assembly is equipped with a camera bracket and an industrial camera. The camera bracket is a three-dimensional movement and rotation bracket. The camera bracket is used to rotate and move the industrial camera. The industrial camera can be raised, lowered, moved, and rotated vertically. The industrial camera is used to capture three-dimensional images of the substrate, the movement trajectory and images of the substrate, and images of the interaction between the substrate and the transfer film.

[0040] B. Operating System Setup:

[0041] A controller, a computer, and water transfer printing operation software are selected. The computer is equipped with the water transfer printing operation software, which is used to perform water transfer printing on the substrate. The computer is connected to the controller. The motor control output terminal of the controller is connected to the control power input terminal of the drive motor and the control power input terminal of the robotic arm motor, respectively. The signal acquisition terminal of the industrial camera is electrically connected to the signal acquisition terminal of the controller. The computer is used to operate the controller, process the acquired image information, perform image simulation, etc.

[0042] Step 2: System Calibration

[0043] Based on the system in step one, a standard substrate is selected for software, hardware, and equipment calibration. The water transfer printing operation software on the computer controls the controller to control the robot arm motor, thereby controlling the robot arm to grasp the standard substrate. Then, the controller controls the drive motor to slide the slider, moving the standard substrate to the transfer area of ​​the water tank (preferably the center of the water tank). Then, the standard substrate is slowly and uniformly lowered to the water surface of the water tank by the moving bracket. The industrial camera will collect the movement trajectory and movement status of the standard substrate in real time, and feed the collected image information back to the computer for analysis, judgment, and selection of the best running path and running speed. After the best running conditions are selected, the computer locks the preliminary running path.

[0044] Step 3: 3D volume modeling

[0045] Select the object to be printed, use 3D modeling software to create a 3D model of the object to be printed, draw the 3D object to be printed, select the center of the water transfer printing area of ​​the 3D object to be printed as the center of the object to be printed, and calculate the ratio between the modeled 3D object to be printed and the actual object to be printed.

[0046] Step 4: 3D Volume Pattern Construction

[0047] Based on the modeling in step three, 3D modeling software is used to model the 3D volume pattern and draw it as the basis for the production of water transfer film. The center of the 3D volume pattern is selected by 3D modeling software as the center of the 3D volume pattern. The 3D volume pattern is assembled with the 3D object to be printed, and the center of the center and the center of the image are set to coincide. The matching between the 3D volume pattern and the 3D object to be printed is checked, analyzed and judged, and the best matching is selected.

[0048] Step 5: 3D Entity Sampling

[0049] Based on the calibration system in step two, a robotic arm is selected to grasp the object to be printed, and it is moved to the transfer area through a sliding mechanism. Then, the object is slowly and uniformly lowered to the water surface of the water tank by a moving support. The industrial camera will collect the movement trajectory and movement status of the object in real time, and feed the collected image information back to the computer for comparison, analysis, judgment and selection of the optimal running path and running speed. After the optimal running conditions are selected, the computer locks the processing running path.

[0050] Step Six: Comparison of 3D Entity and 3D Volume Model

[0051] Based on the 3D entity sampling in step five, the industrial camera performs three-dimensional stereoscopic imaging scanning on the 3D entity and transmits the acquired signal to the computer. The acquired image fed back to the computer by the industrial camera is selected, and the acquired image is compared, analyzed, judged and selected with the 3D model of the 3D entity to be printed. The computer locks the image acquisition path.

[0052] Step 7: Simulation of Water Transfer Film Pattern

[0053] Based on the 3D volume pattern from step four, a planar mapping method is used to perform planar mapping on the surface of the 3D volume pattern. The 3D volume pattern is decomposed into pixels, and pixel block regions are defined. Planar mapping is performed one by one to construct a mapping relationship. Based on this mapping relationship, the pixel mapping image between the 3D volume pattern and the water transfer film pattern is calculated. Pixels can be superimposed and overlapped. The number of overlaps and the overlap area of ​​each pixel are calculated as the basis for color ink printing. The color analysis and distortion judgment of the water transfer film pattern are performed using simulation software on the computer (this software belongs to water transfer printing operation software) to predict whether the water transfer film pattern is distorted.

[0054] Step 8: Water Transfer Film Printing

[0055] Based on the water transfer film pattern from step seven, and using the proportion from step three, color ink is printed on PVA resin (polyvinyl alcohol resin) using an ink printer. The overlapping areas and the number of overlaps are adjusted accordingly with ink. After the water transfer film is printed, it is dried. The layer with ink is called the graphic layer. A solvent-based adhesive is then coated on the graphic layer. The dry base thickness of the solvent-based adhesive is 10-60 μm.

[0056] Step Nine: Water Transfer Printing

[0057] Based on the water transfer film from step eight, place it on the water surface of the water tank (preferably in the center of the tank), fix the water transfer film, spray an activator onto the water transfer film, and based on the processing path from step five, slowly and uniformly move the object to be printed, slide it above the center of the water transfer film, and slowly and uniformly lower the object to be printed. The object to be printed gradually comes into contact with and adheres to the water transfer film, forming the printed object. After the transfer is completed, slowly lift the printed object. This process requires real-time image acquisition, inspection, analysis of the transfer effect, correction, and selection of the optimal water transfer path.

[0058] Step 10: Film Formation and Curing

[0059] Based on the water transfer printing substrate from step nine, it is dried, and the water transfer printing substrate is dried and cured in a suitable temperature environment of 65-75℃.

[0060] Step 11: Mass Production

[0061] Based on the water transfer printing substrate from step ten, film formation is tested, and the process conditions for stable film formation are used for mass production.

[0062] In this configuration, each unitized pixel is a pixel of the same size. By superimposing the unitized pixels in a three-dimensional plane, overlapping pixels will appear. This is done by using the cutting plane with the center of the object to be printed as the reference plane, and mapping the remaining pixels onto this plane.

[0063] Beneficial effects

[0064] This invention employs a water transfer printing method that eliminates the need for a primer on the substrate. It simulates a 3D substrate and a 3D pattern, mapping planes and pixels one-to-one to create a simulated water transfer film. Simulation software refines the film to address distortion issues. An equipment system and industrial camera enable uniform movement and real-time trajectory acquisition of the substrate, facilitating analysis and comparison of the path to select the optimal path and speed for mass production. This combination of software simulation and hardware solves problems in existing water transfer printing technologies, such as cumbersome processes, inaccurate positioning, difficulty in customization, high cost, environmental pollution, and low efficiency. Furthermore, the use of solvent-based adhesives enhances the adhesion of the ink to the substrate, reducing the cost and environmental pollution associated with pre-coating the substrate with a primer. This system and method can be widely applied in water transfer printing production. Attached Figure Description

[0065] Figure 1 This is a schematic diagram of the equipment system structure of a water transfer printing method for substrates that does not require primer spraying according to the present invention.

[0066] Figure 2 This is a schematic diagram of the process structure of a water transfer printing method for substrates that does not require primer spraying according to the present invention.

[0067] Figure 3 This is a simulation diagram of a water transfer printing method for substrates that does not require primer spraying, according to the present invention.

[0068] Figure 4 This is a schematic diagram of a water transfer printing substrate for a water transfer printing method that eliminates the need for a primer, according to the present invention.

[0069] Figure 5 This is a schematic diagram of the pixel acquisition structure of a water transfer printing method for substrates that does not require primer spraying according to the present invention.

[0070] Figure 6 This is a flowchart illustrating the displacement of the water transfer film in a water transfer printing method for substrates that does not require primer spraying, according to the present invention.

[0071] Figure descriptions: 01, Industrial camera assembly; 02, Water tank; 03, Transfer film; 04, Printing substrate; 05, Device support; 06, Controller; 07, Sliding mechanism; 08, Robotic arm. Detailed Implementation

[0072] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0073] In this invention, "multiple" refers to two or more. "And / or": describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0074] See Figures 1-6 A water transfer printing method for substrates that does not require primer application, wherein the water transfer printing method (e.g. Figure 2 (As shown) includes the following steps:

[0075] Step 1: System Setup (Refer to...) Figure 1 As shown:

[0076] A. Setting up the operating equipment:

[0077] A device support 05 is selected, which is a square metal support. A sliding mechanism 07 is installed on the device support 05. The sliding mechanism 07 is horizontally mounted on opposite sides of the device support 05. The sliding mechanism 07 is equipped with a slider, a slide rail, and a drive motor. The drive motor drives the slider to reciprocate on the slide rail, allowing it to be positioned, moved, and stopped at any time. A robotic arm 08 is installed on the slider. The robotic arm 08 is raised, lowered, and rotated via a robotic arm motor and a moving bracket. The robotic arm 08 is equipped with a gripping suction cup and a gripping hand for gripping the printing substrate. 04. The gripping suction cup and gripper can select which robotic arm to use for gripping different substrates 04. A water tank 02 is provided below the device bracket 05. The water tank 02 is used to hold water and transfer film 03, etc. An industrial camera assembly 01 is installed around the water tank 02. The industrial camera assembly 01 is equipped with a camera bracket and an industrial camera. The camera bracket is a three-dimensional movement and rotation bracket. The camera bracket is used to rotate and move the industrial camera. The industrial camera can move vertically, lift, move and rotate, etc. The industrial camera is used to acquire three-dimensional images of the substrate, the movement trajectory and movement images of the substrate, and the interaction images between the substrate and the transfer film, etc.

[0078] B. Operating System Setup:

[0079] Select controller 06, computer and water transfer printing operation software. The computer is equipped with the water transfer printing operation software, which is used to perform water transfer printing on the substrate. The computer is connected to the controller. The motor control output terminal of the controller is connected to the control power input terminal of the drive motor and the control power input terminal of the robot motor respectively. The signal acquisition terminal of the industrial camera is electrically connected to the signal acquisition terminal of the controller. The computer is used to operate the controller, process the acquired image information, perform image simulation, etc.

[0080] Step 2: System Calibration

[0081] Based on the system in step one, a standard substrate is selected for software, hardware, and equipment calibration. The water transfer printing operation software on the computer controls the controller to control the robot arm motor, thereby controlling the robot arm to grasp the standard substrate. Then, the controller controls the drive motor to slide the slider, moving the standard substrate to the transfer area of ​​the water tank (preferably the center of the water tank). Then, the standard substrate is slowly and uniformly lowered to the water surface of the water tank by the moving bracket. The industrial camera will collect the movement trajectory and movement status of the standard substrate in real time, and feed the collected image information back to the computer for analysis, judgment, and selection of the best running path and running speed. After the best running conditions are selected, the computer locks the preliminary running path.

[0082] Step 3: 3D volume modeling

[0083] Select the substrate to be printed, and use 3D modeling software to create a 3D model of the substrate. The center of the water transfer printing area on the 3D substrate is selected using the 3D modeling software as the center of gravity. The ratio between the modeled 3D substrate and the actual substrate is calculated. Furthermore, 3D simulation software is used to simulate the 3D substrate. Figure 3 Figure (2) shown;

[0084] Step 4: 3D Volume Pattern Construction

[0085] Based on the modeling in step three, 3D modeling software is used to model the 3D volume pattern and draw it as the basis for the production of water transfer film. The center of the 3D volume pattern is selected by 3D modeling software as the center of the 3D volume pattern. The 3D volume pattern is assembled with the 3D object to be printed, and the center of the center and the center of the image are set to coincide. The matching between the 3D volume pattern and the 3D object to be printed is checked, analyzed and judged, and the best matching is selected.

[0086] Step 5: 3D Entity Sampling

[0087] Based on the calibration system in step two, a robotic arm is selected to grasp the object to be printed (e.g., Figure 3 As shown in Figure (1), the object is moved to the transfer area by the sliding mechanism, and then slowly and uniformly lowered to the water surface of the water tank by the moving bracket. The industrial camera will collect the movement trajectory and movement status of the object in real time, and feed the collected image information back to the computer for comparison, analysis, judgment and selection of the best running path and running speed, etc. After the best running conditions are selected, the computer locks the processing running path.

[0088] Step Six: Comparison of 3D Entity and 3D Volume Model

[0089] Based on the 3D entity sampling in step five, the industrial camera performs three-dimensional stereoscopic imaging scanning on the 3D entity and transmits the acquired signal to the computer. The acquired image fed back to the computer by the industrial camera is selected, and the acquired image is compared, analyzed, judged and selected with the 3D model of the 3D entity to be printed. The computer locks the image acquisition path.

[0090] Step 7: Simulation of Water Transfer Film Pattern

[0091] Based on the 3D volume pattern from step four, a planar mapping method is used to perform planar mapping on the surface of the 3D volume pattern. The 3D volume pattern is decomposed into pixels, and pixel blocks are defined for one-to-one planar mapping to construct the mapping relationship, such as... Figure 5The selection shown involves radiating outwards from the center of the substrate to define unitized pixels and pixel regions. Based on this mapping relationship, a pixel mapping image between the 3D volume pattern and the water transfer film pattern is calculated. Pixels can be superimposed and overlapped, and the number of overlaps and the overlap area of ​​each pixel are calculated as the basis for color ink printing. Here, the cutting plane with the center of the substrate as the cutting point is used as the reference plane, and the remaining pixels are mapped onto this plane. Color analysis and distortion judgment of the water transfer film pattern are performed using simulation software on a computer (this software belongs to water transfer printing operation software) to predict whether the water transfer film pattern is distorted.

[0092] Step 8: Water Transfer Film Printing

[0093] Based on the water transfer film pattern from step seven, and using the proportions from step three, color ink is printed onto PVA resin (polyvinyl alcohol resin) using an ink printer. The overlapping areas and number of overlaps are adjusted with appropriate ink additions. After printing, the water transfer film is dried, leaving an ink layer called the image layer. A solvent-based adhesive is then applied to this image layer. This solvent-based adhesive is selected from polyurethane resin, and its dry base thickness is 40µm. [The text abruptly ends here, likely due to an incomplete sentence or missing information.] Figure 3 Figure (3) shown;

[0094] Step Nine: Water Transfer Printing

[0095] Based on the water transfer film from step eight, place it on the water surface of the tank (preferably in the center), fix the film in place, and spray an activator onto it. This activator is a plasticizer dissolved in a volatile solvent. Following the processing path from step five, the substrate to be printed is moved slowly and uniformly, gliding above the center of the water transfer film, and then slowly and uniformly descending. The substrate gradually comes into contact with and adheres to the water transfer film, thus forming the printed substrate. This process can be aided by… Figure 6 The direction of the calibration material is shown. Analyze the trajectory of the oil film during water transfer printing. The oil film will deform under the action of the substrate. This deformation is variable and non-uniform. It is necessary to use an industrial camera to collect images of the changes in real time and feed them back to the computer for analysis to determine the best route. After the transfer is completed, the substrate is slowly lifted. This process requires the industrial camera to collect images in real time, check and analyze the transfer effect, make corrections, and select the best water transfer path.

[0096] Step 10: Film Formation and Curing

[0097] Based on the water transfer printing substrate from step nine, it is dried. The substrate is dried and cured at a suitable temperature of 65-75℃ to form the final substrate, such as... Figure 4 As shown;

[0098] Step 11: Mass Production

[0099] Based on the water transfer printing substrate from step ten, film formation is tested, and the process conditions for stable film formation are used for mass production.

[0100] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A water transfer printing method for substrates that does not require primer, characterized in that, The water transfer printing method includes the following steps: Step 1: System Setup A. Setting up the operating equipment: A device support is selected, and a sliding mechanism is installed on the device support. A robotic arm is installed on the sliding mechanism. The sliding mechanism is used to drive the robotic arm to slide. The robotic arm is used to grasp and move the object to be printed. A water tank is provided below the device support. The water tank is used to hold water and transfer film. An industrial camera assembly is installed around the water tank. The industrial camera assembly is equipped with a camera bracket and an industrial camera. The camera bracket is selected as a three-dimensional movement and rotation bracket. The camera bracket is used to rotate and move the industrial camera. B. Operating System Setup: A controller, a computer, and water transfer printing operation software are selected. The computer is equipped with the water transfer printing operation software, which is used to perform water transfer printing on the substrate. The computer is externally connected to the controller, which is electrically connected to the power terminals of the sliding mechanism, the robot arm, and the industrial camera assembly. Step 2: System Calibration Based on the system in step one, the standard substrate is moved to the area to be transferred in the water tank, and then slowly and uniformly lowered to the water surface in the tank. The industrial camera will collect the movement trajectory and movement status of the standard substrate in real time, and feed the collected image information back to the computer to form a preliminary running path. Step 3: 3D volume modeling Select the object to be printed, use 3D modeling software to create a 3D model of the object to be printed, and calculate the ratio between the modeled 3D object and the actual object to be printed. Step 4: 3D Volume Pattern Construction Based on the modeling in step three, 3D modeling software is used to model the 3D body pattern, draw the 3D body pattern, and assemble the 3D body pattern with the 3D body to be printed. Step 5: 3D Entity Sampling Based on the calibration system in step two, a robotic arm is selected to grab the object to be printed and slowly and uniformly lower it to the water surface in the water tank. An industrial camera collects images in real time and feeds the collected image information back to the computer to form a processing operation path. Step Six: Comparison of 3D Entity and 3D Volume Model Based on the 3D entity sampling in step five, the industrial camera performs imaging scanning on the 3D entity, transmits the acquired image to the computer, and compares the acquired image with the 3D model of the 3D entity to be printed to form an image acquisition path. Step 7: Simulation of Water Transfer Film Pattern Based on the 3D volume pattern from step four, a planar mapping method is used to perform planar mapping of the surface of the 3D volume pattern. Unitized pixel decomposition is used to perform one-to-one planar mapping, and the unitized pixels are superimposed and overlapped. The number of overlaps and the overlap area of ​​each unitized pixel are calculated. Step 8: Water Transfer Film Printing Based on the water transfer film pattern in step seven, and using the proportion from step three, color ink is printed on polyvinyl alcohol resin using an ink printer. The overlapping areas and the number of overlaps are adjusted accordingly with ink. After the water transfer film is printed and the ink dries, a solvent-based adhesive is applied to the ink layer. Step Nine: Water Transfer Printing Based on the water transfer film in step eight, place it on the water surface of the water tank, fix the water transfer film, spray an activator on the water transfer film, and based on the processing and operation path in step five, gradually bring the object to be printed into contact with the water transfer film and adhere it to the object to be printed. Step 10: Film Formation and Curing Based on the water transfer printing substrate from step nine, it is dried, and the water transfer printing substrate is dried and cured in a suitable temperature environment of 65-75℃.

2. The water transfer printing method for substrates without primer as described in claim 1, characterized in that, The activator in step nine is selected from plasticizers dissolved in volatile solvents.

3. The water transfer printing method for substrates without primer as described in claim 1, characterized in that, The solvent-based adhesive used in step eight is selected from polyurethane resin or acrylic resin.

4. The water transfer printing method for substrates without primer as described in claim 3, characterized in that, The dry base thickness of the solvent-based adhesive is 10–60 μm.

5. The water transfer printing method for substrates without primer as described in claim 4, characterized in that, The dry basis thickness of the solvent-based adhesive is 30–40 μm.

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