A roll coating method and roll coating apparatus thereof

Abstract

This invention discloses a roller coating method and roller coating equipment, belonging to the field of roller coating technology. The roller coating method includes rotating a scraper roller against the surface of a coating roller and / or a pressing roller that has already undergone coating operations to remove residual old paint; reusing the coating roller and / or pressing roller after removing the old paint for coating operations and supplying new paint to their surface; and transferring the new paint to the workpiece surface through the coating roller and / or pressing roller. The roller coating equipment includes a conveyor, a coating device, and a circumferential scraper device. This invention, through a cyclical method of first removing residual old paint, then supplying new paint, and then transferring the coating, avoids coating amount fluctuations caused by the mixing of old and new paint, ensures uniform paint film thickness, prevents transverse texture defects on the workpiece surface, and simultaneously reduces roller wear and extends equipment service life.

Description

Technical Field

[0001] This invention relates to the field of roller coating technology, specifically a roller coating method and roller coating equipment. Background Technology

[0002] A roller coating machine is a device that uses multiple rotating rollers to uniformly coat paint onto the surface of workpieces such as wood, metal, and plastic using a "transfer" method. For example, Chinese patent CN201610913684.3 discloses such a roller coating machine. However, in the above-mentioned prior art, after the rollers complete a coating operation, a small amount of paint often remains on their surface. This residual old paint mixes with the subsequently supplied new paint, causing fluctuations in the coating amount. This results in uneven paint film thickness on the workpiece surface, differences in leveling and reflectivity between thick and thin areas, and ultimately, obvious transverse lines (commonly known as uneven surfaces) defects appearing on the workpiece after drying. This problem is particularly prominent on workpieces with a small coating amount or dark paint color.

[0003] To address the aforementioned issues, relevant technical personnel have conducted improvements and research. For example, Chinese patent CN202121439364.1 discloses a paint roller coating device, which uses a scraper mechanism (scraper) to remove residual paint from the surface of the coating roller and auxiliary roller, aiming to ensure a consistent feed amount for each coating. However, in this solution, the scraper and roller are in a friction fit, which can easily lead to scratches, wear, or even roughening of the roller surface during long-term operation. This prevents the paint from forming a smooth liquid film during transfer, and foreign objects (such as dust particles) can easily get stuck in the contact gap between the scraper and the roller. This not only causes uneven paint distribution but may also lead to stringy coating defects, thus affecting the final coating quality of the workpiece.

[0004] Therefore, further improvements are necessary. Summary of the Invention

[0005] The present invention aims to provide a roller coating method and roller coating equipment to overcome the shortcomings of the prior art.

[0006] A roller coating method designed for this purpose includes the following steps: The scraper roller is rotated and pressed against the surface of the coating roller and / or pressure roller that has already been coated, so that the scraper roller removes the old paint residue on the surface of the coating roller and / or pressure roller through rotational contact. The paint spreading rollers and / or pressure rollers, after removing the old paint, are reused for the coating operation, and new paint is supplied to the surface of the paint spreading rollers and / or pressure rollers; A coating cycle is completed by transferring new paint to the surface of the workpiece using a paint spreading roller and / or a paint pressing roller.

[0007] The roller coating method also includes the step of adjusting the overall height of the coating roller and the pressing roller by means of a lifting device, so as to maintain a preset coating gap between the coating roller and the workpiece surface.

[0008] The rotation method by which the paint scraper roller removes residual old paint is as follows: The scraper roller achieves passive rotation by contact with the surfaces of the paint spreading roller and / or the paint pressing roller, and generates a constant scraping force by utilizing their opposite directions of motion; or, the scraper roller is driven to rotate actively by an independent driver, and the scraping force is adjusted by controlling the rotation direction between the scraper roller and the paint spreading roller and / or the paint pressing roller to be the same or opposite.

[0009] The roller coating method also includes the step of adjusting the working mode of the scraper roller. The rotation state of the scraper roller is controlled by the rotation limit part to select the matching mode between the scraper roller and the paint spreading roller and / or the pressure roller.

[0010] When the rotation limiting part is in the non-limited state, the paint scraper roller is allowed to rotate, and the paint scraper roller forms a rolling engagement with the paint spreading roller and / or the paint pressing roller; when the rotation limiting part is in the limited state, the paint scraper roller is restricted from rotating, and the paint scraper roller forms a friction engagement with the paint spreading roller and / or the paint pressing roller.

[0011] The roller coating method also includes the step of adjusting the contact pressure between the scraper roller and the cloth roller and / or the pressure roller before removing residual old paint: the connecting shaft is driven to rise and fall by the scraper roller adjustment assembly, and the connecting shaft drives the swing block and the scraper roller mounted on the swing block to rise and fall together to set the optimal scraper contact pressure. Alternatively, the paint scraping roller can rotate on the swing block and move along the trajectory of the adjustment groove on the swing block.

[0012] The roller coating method also includes the step of, after removing residual old paint, squeezing and spreading the new paint on the surface of the paint spreading roller by the relative rotation of the pressure roller and the spreading roller, so that the new paint is evenly distributed on the surface of the spreading roller.

[0013] The roller coating method also includes a step of cleaning the paint accumulation at the ends of the coating roller and / or the pressing roller while removing residual old paint: the old paint residue at the ends of the coating roller and / or the pressing roller is scraped off by the end scraper blade, and the scraped paint is discharged through the end guide groove.

[0014] The roller coating method also includes a step of recovering the removed old paint: the old paint discharged from the roller surface and / or end guide trough during the removal process is collected into a paint collection unit through a paint recovery box and an inclined recovery trough.

[0015] A roller coating apparatus includes the above-described roller coating method, wherein the roller coating apparatus comprises: Conveyors are used to transport workpieces; The coating device includes a paint spreading roller, a paint pressing roller, and a driver. The paint spreading roller and the paint pressing roller are arranged back and forth along the conveying direction of the conveyor, and the two are driven to rotate relative to each other by the driver. The paint spreading roller is used to transfer paint to the surface of the workpiece. A circumferential paint scraping device is installed on the paint spreading roller and / or the paint pressing roller, including a paint scraping roller. After completing one coating, the paint scraping roller rotates and abuts against the surface of the paint spreading roller and / or the paint pressing roller to remove the old paint residue on the surface of the paint spreading roller and / or the paint pressing roller.

[0016] The roller coating equipment also includes a lifting device, which is installed on the conveyor and connected to the coating device drive to drive the coating device to lift and lower as a whole to adjust the coating height.

[0017] The circumferential scraping device also includes a scraping roller bracket, which is mounted on the coating device; the scraping roller is directly rotatably connected to the scraping roller bracket, or the scraping roller is rotatably connected to the scraping roller bracket via a swing mechanism, the swing mechanism including a connecting shaft rotatably mounted on the scraping roller bracket and a swing block fixed on the connecting shaft, the scraping roller being rotatably connected to the swing block.

[0018] The paint scraper roller bracket is also equipped with a paint scraper roller adjustment component, which is driven to the connecting shaft to raise and lower the connecting shaft and drive the swing block and paint scraper roller to raise and lower, so as to adjust the abutment pressure of the paint scraper roller.

[0019] The coating device further includes a fixed end guide groove and an end scraper plate disposed on the end guide groove. The end guide groove is located at the end of the coating roller and / or the pressing roller, and the end scraper plate abuts against the end face of the coating roller and / or the pressing roller to remove accumulated paint at the end.

[0020] The conveyor is equipped with a paint recycling box and an inclined recycling trough. The paint recycling box is located below the end guide trough, and the inclined recycling trough is located in the area below the paint spreading roller and the paint pressing roller, and is used to recycle the old paint that has been removed.

[0021] Through the above improvements, this invention achieves the following technical effects through a complete cyclical method of "first cleaning, then supplying, then coating": 1. Before each resupply of new paint, a special step is set up to remove residual old paint from the surface of the paint application roller and / or pressure roller by rotating the paint scraper roller against it. This fundamentally avoids the problem of unstable coating amount caused by the mixing of old paint with subsequent new paint, and ensures that the amount of paint transferred to the workpiece surface each time is accurate and consistent. This ensures that the paint film thickness on the workpiece surface is highly uniform and effectively prevents transverse lines (i.e., "yin-yang surface" defects) caused by uneven thickness.

[0022] Second, since residual old paint is removed, each coating starts afresh on a "clean" roller surface. This is especially important for thin-coat processes that require very little coating or for darker paint colors. It can completely solve the problem of color difference or leveling difference caused by trace amounts of old paint mixing in, and greatly improve the coating quality of the final product.

[0023] Third, it abandons the traditional hard scraping method and adopts a "roller-to-roller" rotating contact cleaning method, which greatly reduces the wear on the surface of the paint application roller and / or pressure roller, avoids premature roller failure due to scratches and roughening, and significantly extends the service life of the paint application roller and / or pressure roller. At the same time, the rotating contact method is less likely to cause foreign objects to get stuck, eliminating coating defects such as paint stringing or uneven distribution caused by foreign objects.

[0024] Fourth, the three steps of removing old paint, supplying new paint, and transferring coating are organically combined into a complete closed-loop cycle. The removal step creates ideal initial conditions for subsequent paint supply and coating, making the entire coating process more stable, controllable, and repeatable, ensuring the long-term stability of the equipment and the consistency of coating quality. Attached Figure Description

[0025] Figure 1 This is an exploded structural diagram of an embodiment of the present invention.

[0026] Figure 2 This is an exploded structural diagram from another perspective of an embodiment of the present invention.

[0027] Figure 3 This is a schematic diagram of the assembly cross-sectional structure according to an embodiment of the present invention.

[0028] Figure 4 This is a schematic diagram of the assembly cross-sectional structure from another perspective of an embodiment of the present invention.

[0029] Figure 5 for Figure 3 A magnified structural diagram at point X in the diagram.

[0030] Figure 6 This is an exploded structural diagram of the coating device and the circumferential paint scraping device.

[0031] Figure 7 This is an exploded structural diagram of the coating device and the circumferential scraping device from another perspective.

[0032] Figure 8 for Figure 6 A magnified structural diagram of point Y in the diagram.

[0033] Figure 9 This is an exploded view of the coating apparatus.

[0034] Figure 10 This is an exploded structural diagram of the coating apparatus from another perspective.

[0035] Figure 11 This is an exploded structural diagram of the end guide groove, the end scraper, and the end guide groove support. Detailed Implementation

[0036] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0037] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0038] See Figures 1-11 This roller coating method includes the following steps: The scraper roller C1 is rotated to press against the surface of the coating roller B1 and / or the pressure roller B2, which have already been coated, so that the scraper roller C1 can remove the old paint residue on the surface of the coating roller B1 and / or the pressure roller B2 through rotational contact. After removing the old paint, the paint spreading roller B1 and / or the paint pressing roller B2 are reused for the coating operation, and new paint is supplied to the surface of the paint spreading roller B1 and / or the paint pressing roller B2. New paint is transferred to the workpiece surface by the paint spreading roller B1 and / or the paint pressing roller B2, thus completing one coating cycle.

[0039] The roller coating method also includes the step of adjusting the overall height of the paint spreading roller B1 and the paint pressing roller B2 by means of the lifting device A, so that the paint spreading roller B1 and the workpiece surface maintain a preset coating gap.

[0040] The rotation method of the paint scraper roller C1 to remove residual old paint is as follows: The paint scraper roller C1 achieves passive rotation by contact with the surfaces of the paint spreading roller B1 and / or the paint pressing roller B2, and generates a constant scraping force by utilizing their opposite directions of motion; or, the paint scraper roller C1 is driven to rotate actively by an independent driver, and the scraping force is adjusted by controlling the rotation direction between the paint scraper roller C1 and the paint spreading roller B1 and / or the paint pressing roller B2 to be the same or opposite.

[0041] The roller coating method also includes the step of adjusting the working mode of the scraper roller C1. The rotation state of the scraper roller C1 is controlled by the rotation limit part to select the cooperation mode between the scraper roller C1 and the paint spreading roller B1 and / or the pressure roller B2.

[0042] When the rotation limiting part is in the non-limited state, the paint scraper roller C1 is allowed to rotate, and the paint scraper roller C1 forms a rolling engagement with the paint spreading roller B1 and / or the paint pressing roller B2; when the rotation limiting part is in the limited state, the paint scraper roller C1 is restricted from rotating, and the paint scraper roller C1 forms a friction engagement with the paint spreading roller B1 and / or the paint pressing roller B2.

[0043] The roller coating method also includes the step of adjusting the contact pressure between the scraper roller C1 and the spreading roller B1 and / or the pressure roller B2 before removing residual old paint: The paint scraper roller adjustment assembly C5 drives the connecting shaft C3 to rise and fall. The connecting shaft C3 drives the swing block C4 and the paint scraper roller C1 installed on the swing block C4 to rise and fall together, so as to set the optimal paint scraping pressure.

[0044] Alternatively, the paint scraping roller C1 rotates on the swing block C4 and moves along the trajectory of the adjustment groove C4.2 on the swing block C4.

[0045] The roller coating method also includes the step of, after removing residual old paint, pressing and spreading new paint on the surface of the paint spreading roller B1 by the relative rotation of the pressure roller B2 and the spreading roller B1, so that the new paint is evenly distributed on the surface of the spreading roller B1.

[0046] The roller coating method also includes a step of cleaning the paint accumulation at the ends of the coating roller B1 and / or the pressing roller B2 while removing residual old paint: the old paint remaining at the ends of the coating roller B1 and / or the pressing roller B2 is scraped off by the end scraper B4, and the scraped paint is discharged through the end guide groove B3.

[0047] The roller coating method also includes a step of recovering the removed old paint: the old paint discharged from the roller surface and / or end guide trough B3 during the removal process is collected into the paint collection unit through the paint recovery box 300 and the inclined recovery trough 400.

[0048] The above-described roller coating method can be applied to roller coating equipment. The roller coating equipment includes: Conveyor 100 is used to transport workpieces; The coating device B includes a paint spreading roller B1, a paint pressing roller B2 and a driver. The paint spreading roller B1 and the paint pressing roller B2 are arranged back and forth along the conveying direction of the conveyor 100 and are driven to rotate relative to each other by the driver. The paint spreading roller B1 is used to transfer paint to the surface of the workpiece. A circumferential paint scraping device C is installed on the paint spreading roller B1 and / or the paint pressing roller B2, including a paint scraping roller C1. After completing one coating, the paint scraping roller C1 rotates and abuts against the surface of the paint spreading roller B1 and / or the paint pressing roller B2 to remove the old paint residue on the surface of the paint spreading roller B1 and / or the paint pressing roller B2.

[0049] In this embodiment, the conveyor 100 serves as the base and workpiece conveying platform of the equipment. It includes a conveyor frame, multiple conveyor rollers or conveyor belts mounted on the frame, and a conveyor drive motor that drives the conveyor rollers or conveyor belts to rotate. During operation, the conveyor drive motor drives the conveyor rollers or conveyor belts to rotate via chain drive or gear drive, thereby stably conveying the sheet metal workpieces placed on it to the coating station in a straight line. The conveying speed of the conveyor 100 can be steplessly adjusted via a frequency converter to adapt to the needs of different coating processes. The conveyor frame is constructed from high-strength profiles welded or spliced ​​together, ensuring the rigidity and stability of the overall structure and preventing deformation under heavy loads.

[0050] The conveyor 100 is equipped with a lifting device A, and the coating device B is driven to move up and down through the lifting device A.

[0051] The lifting device A is the core adjustment mechanism of this equipment, which includes: guide columns fixed on both sides of the conveyor 100, linear guide rail pairs mounted on the columns, and a lifting slide plate fixedly connected to the coating device B. The guide columns are precision-machined square steel with guide rail mounting surfaces. The linear guide rail pairs include guide rails and sliders; the guide rails are fixed on the columns, and the sliders are connected to the lifting slide plate. The lifting drive source can be an electric push rod, a cylinder, or a servo motor with a screw drive mechanism, or a manual turntable with a screw drive mechanism. In this embodiment, a manual turntable driving a precision ball screw is preferred, with its power output end (screw nut) connected to the lifting slide plate drive. During operation, the manual turntable precisely controls the number of rotations, converting the rotational motion into linear motion of the lifting slide plate through the ball screw, pushing the lifting slide plate to slide precisely up and down along the linear guide rail pairs, thereby driving the coating device B fixed thereon to move up and down relative to the conveyor 100. The use of linear guide pairs ensures the smoothness and positioning accuracy of the lifting motion, with a repeatability of ±0.05mm. The closed-loop control of the servo motor enables controllable height position.

[0052] Driven by the lifting device A, the gap between the coating device B and the workpiece surface on the conveyor 100 can be precisely adjusted, thus adapting to workpieces of different thicknesses, from thin decorative panels to solid wood boards tens of millimeters thick, achieving flexible coating height adjustment and greatly improving the applicability of the equipment.

[0053] The coating device B includes a paint spreading roller B1, a paint pressing roller B2, and a driver. The paint spreading roller B1 and the paint pressing roller B2 are arranged back and forth along the conveying direction of the conveyor 100 and rotate relative to each other by the drive of the driver.

[0054] In this embodiment, the paint-spreading roller B1 and the paint-pressing roller B2 are arranged back and forth along the conveying direction (i.e., the workpiece forward direction) of the conveyor 100, with their axes parallel to each other, and the center distance can be adjusted within a certain range according to process requirements. The driver provides power to make them rotate relative to each other.

[0055] Specifically, the main function of the pressure roller B2 is to adjust the state of the paint on the surface of the paint roller B1, and it does not directly contact the surface of the workpiece passing below.

[0056] The working process is as follows: First, the paint is transferred to the surface of the spreading roller B1, forming an initial paint film. Then, the pressing roller B2 rotates relative to the spreading roller B1, creating a precisely controlled gap between them. As the spreading roller B1 carries the paint through this gap, the pressing roller B2 exerts a squeezing and shearing action on the paint on the surface of the spreading roller B1, pushing back any excess paint that may be present on the surface of the spreading roller B1. Simultaneously, it further compacts, spreads, and levels the paint, ensuring that the paint on the surface of the spreading roller B1 reaches a more uniform and smooth state before being transferred to the workpiece.

[0057] After being homogenized by the pressure roller B2, the paint distribution roller B1 transfers the stable and uniformly thick paint to the surface of the workpiece passing below.

[0058] The surface of the paint roller B1 is mirror-polished and can also be engraved with specific cell structures (such as pyramid or prismatic) to control the amount of paint carried. The depth and density of the cells are designed according to the required coating amount. The surface of the pressure roller B2 is mirror-polished to ensure that when it interacts with the paint roller B1, it can press the paint on the surface of the paint roller B1 to be smooth and flat.

[0059] A circumferential paint scraping device C is provided on the paint spreading roller B1 and / or the paint pressing roller B2. The circumferential paint scraping device C includes a paint scraping roller C1, which rotates and abuts against the surface of the paint spreading roller B1 and / or the paint pressing roller B2.

[0060] In this embodiment, the coating device B is raised and lowered as a whole by the lifting device A, so as to flexibly adjust the coating height for workpieces of different thicknesses. At the same time, the rotating contact of "roller to roller" replaces the sliding contact of the traditional rigid scraper. The scraper roller C1 rotates and abuts against the surface of the paint spreading roller B1 and / or the pressure roller B2, effectively removing the old paint residue on the roller surface. This avoids the coating amount fluctuation caused by the mixing of old and new paint, and ensures that the amount of paint transferred to the workpiece surface is uniform each time. This ensures uniform paint film thickness and prevents the workpiece surface from producing transverse lines, i.e., "yin-yang surface" defects, due to uneven thickness. It is especially suitable for high-precision coating processes such as thin coating (such as micro coating of 20-30g / m²) or dark color (such as black, dark walnut color). In addition, the rotary contact method can significantly reduce surface wear of the paint spreading roller B1 and / or the paint pressing roller B2, avoid premature scrapping of the rollers due to scratches and roughening, significantly extend service life (by 2-3 times), reduce equipment maintenance costs and downtime, and also prevent foreign objects (such as workshop dust and fiber debris) from getting stuck on the contact surface, effectively eliminating coating failures such as paint stringing or uneven distribution caused by foreign objects, ensuring the long-term stability of equipment operation and the consistency of coating quality.

[0061] There are two possible implementation methods for driving the paint scraper roller C1.

[0062] In the first embodiment, the scraper roller C1 directly abuts against the surface of the paint spreading roller B1 and / or the pressure roller B2, without a separate drive. When the paint spreading roller B1 and / or the pressure roller B2 rotate, the scraper roller C1 follows and rotates passively due to the friction between the surfaces of the paint spreading roller B1 and / or the pressure roller B2. At this time, since the scraper roller C1 and the paint spreading roller B1 and / or the pressure roller B2 are in abutting relationship, the rotation direction of the scraper roller C1 is opposite to the rotation direction of the paint spreading roller B1 and / or the pressure roller B2. This passive method has a simple structure, requires no additional power and control system, and is low in cost. It achieves the scraping effect by relying on the speed difference between the surfaces of the scraper roller C1 and the paint spreading roller B1 and / or the pressure roller B2, and is especially suitable for paints with low viscosity (such as UV-cured paints and water-based primers).

[0063] In the second embodiment, the circumferential paint scraping device C further includes a paint scraping roller driver. The paint scraping roller driver (which can be a variable frequency motor or a servo motor) is driven to rotate the paint scraping roller C1, causing it to actively rotate and abut against the surface of the paint spreading roller B1 and / or the paint pressing roller B2. By controlling the direction and speed of the paint scraping roller driver, the rotation direction of the paint scraping roller C1 can be the same as or opposite to the rotation direction of the paint spreading roller B1 and / or the paint pressing roller B2, and the speed difference between the two can be precisely adjusted. When the rotation directions are opposite, a stronger shearing force can be generated, enhancing the paint scraping effect, which is suitable for high-viscosity paints (such as polyester paint, PU paint) or occasions requiring strong removal of stubborn residues; when the rotation directions are the same, by adjusting the speed difference (e.g., the paint scraping roller speed is slightly faster or slightly slower than the working roller), more precise paint control can be achieved, such as forming a uniform thin layer of paint film on the roller surface. In this embodiment, multiple paint scraping modes are provided, enabling the equipment to flexibly adjust the working mode of the paint scraping roller according to different paint characteristics (viscosity, solid content, thixotropy) and process requirements (coating amount, surface effect, production line speed). From simple passive paint scraping to precise active control, the equipment's process adaptability and control accuracy are greatly improved, meeting diverse production needs.

[0064] The circumferential paint scraping device C also includes a paint scraping roller bracket C2, which is mounted on the coating device B or the conveyor 100. The paint scraping roller C1 is directly positioned and rotatably connected to the paint scraping roller bracket C2, or the paint scraping roller C1 is oscillatingly rotatably connected to the paint scraping roller bracket C2.

[0065] In this embodiment, the scraper roller bracket C2 is preferably fixedly mounted on the paint spreading roller bracket B6 of the coating device B, and secured with high-precision positioning pins and bolts to ensure a precise relative positional relationship with the working roller. The end of the scraper roller C1 is rotatably connected to the scraper roller bracket C2 via rolling bearings or other means. This embodiment provides two connection methods: one is that the end of the scraper roller C1 is directly positioned and rotatably connected to the scraper roller bracket C2, i.e., fixed-axis rotation, which has the advantages of simple structure and sufficient rigidity, and is suitable for occasions with extremely high requirements for scraping position accuracy, stable roller size, and no significant vibration; the other is that the end of the scraper roller C1 is oscillatingly rotatably connected to the scraper roller bracket C2, i.e., its axis can swing around a fulcrum within a certain angle range, thereby adaptively contacting the surface of the paint spreading roller B1 and / or the paint pressing roller B2, ensuring uniform contact pressure, and is especially suitable for working conditions where the roller has slight radial runout (due to manufacturing tolerances or installation errors) or thermal deformation (due to frictional heat or process temperature changes).

[0066] The paint scraper roller C1 in this embodiment, through diverse installation methods, not only ensures its positioning accuracy and structural rigidity, but also provides the possibility of adaptive fitting. This ensures that the paint scraper roller C1 can maintain good and uniform line contact with the paint spreading roller B1 and / or the paint pressing roller B2 under various working conditions, maintain a stable paint scraping effect, and at the same time avoid excessive local pressure or poor contact caused by excessive rigidity.

[0067] In this embodiment, the paint scraper roller C1 preferably adopts a swing-type rotary connection.

[0068] Specifically, a connecting shaft C3 is rotatably mounted on the paint scraper roller bracket C2. Both ends of the connecting shaft C3 are supported on the paint scraper roller bracket C2 by rolling bearings, allowing free rotation. A swing block C4 is fixedly connected to the connecting shaft C3. The connecting shaft C3 and the swing block C4 are connected by a key or tight fit to form a linkage structure. The swing blocks C4 are symmetrically arranged at both ends of the connecting shaft C3 to ensure balanced force on the paint scraper roller C1. The end of the paint scraper roller C1 is rotatably connected to the swing block C4 via rolling bearings. When the paint scraper roller C1 is subjected to external force (such as the reaction force generated when it contacts the paint spreading roller B1 and / or the paint pressing roller B2), it will drive the swing block C4 to swing around the axis of the connecting shaft C3, thereby realizing the swing-type rotation of the paint scraper roller C1 on the paint scraper roller bracket C2. This floating installation structure allows the paint scraper roller C1 to conform to the surface of the paint spreading roller B1 and / or the paint pressing roller B2 in an adaptive state, forming a "follow-motion" effect. Even if the paint spreading roller B1 and / or the paint pressing roller B2 experience slight radial runout due to installation errors, bearing clearances, thermal expansion, or high-speed rotation, the paint scraping roller C1 can maintain a tight fit through oscillation, ensuring a continuous and stable paint scraping effect. At the same time, it avoids the impact and vibration caused by rigid fixed connections, effectively protecting the roller surface and the bearings at both ends, and reducing operating noise.

[0069] In order to precisely control the contact pressure or gap between the paint scraping roller C1 and the working roller, this embodiment provides two preferred adjustment methods.

[0070] In the first adjustment method, a scraper roller adjustment component C5 is provided on the scraper roller bracket C2. The scraper roller adjustment component C5 is driven to connect with the connecting shaft C3. The connecting shaft C3 is driven to rise and fall on the scraper roller bracket C2 by the scraper roller adjustment component C5, and drives the swing block C4 and the scraper roller C1 to rise and fall together during the rising and falling.

[0071] In this embodiment, the adjustment component C5 includes an adjustment seat fixed to the paint scraper roller bracket C2, an adjustment screw passing through the adjustment seat, and a drive block connected to the end of the adjustment screw. The drive block is fixedly connected to or abuts against the end of the connecting shaft C3. The adjustment screw can be a manually adjustable threaded rod equipped with a locking nut; it can also be a transmission rod connected to a pneumatic, hydraulic actuator, or servo motor to achieve remote or automatic control. During operation, by rotating the adjustment screw or driving the actuator, the drive block can be pushed up and down, thereby driving the connecting shaft C3 to move up and down within the mounting seat on the paint scraper roller bracket C2. When the connecting shaft C3 moves up and down, it will drive the swing block C4 fixed thereto and the paint scraper roller C1 mounted on the swing block C4 to move up and down together, thereby precisely adjusting the abutment position and contact pressure between the paint scraper roller C1 and the paint spreading roller B1 or the paint pressing roller B2. In some designs, the adjustment component C5 may also include a pressure sensor or a scale indicator to display or set the contact pressure value in real time. This enables quantitative adjustment and precise control of the paint scraping pressure. Optimal paint scraping pressure parameters (e.g., a linear pressure range of 0.5-5 kg / cm) can be set based on the viscosity, solid content, temperature, and production line speed of different paints. This ensures thorough removal of residual paint while avoiding excessive pressure that could damage the coating or covering layer on the roller surface. Furthermore, after long-term operation, the adjustment components can compensate for minor wear on the roller surface, maintaining consistent paint scraping performance and significantly extending equipment maintenance cycles and roller lifespan. Pneumatic or servo-driven adjustment methods also allow for online automatic adjustment to adapt to process changes.

[0072] In the second adjustment method, the swing block C4 is provided with an adjustment groove C4.2, which extends toward the paint spreading roller B1 and / or the paint pressing roller B2. The end of the scraper roller C1 is rotatably connected to the adjustment groove C4.2 via a bearing seat or a slider structure and can move along the trajectory of the adjustment groove C4.2. Specifically, the adjustment groove C4.2 is an elongated hole or groove opened on the swing block C4, and its extension direction generally points toward the axis of the paint spreading roller B1 and / or the paint pressing roller B2. The end shaft of the scraper roller C1 passes through the adjustment groove C4.2 and can slide along the extension direction within the groove to change the axis position of the scraper roller C1. The side or end of the adjustment groove C4.2 is provided with a locking mechanism (such as a locking screw, an eccentric clamping block, or a quick clamp) for fixing the scraper roller C1 after it has been adjusted to the desired position.

[0073] By setting the adjustment groove C4.2, the operator can manually adjust the fixed position of the end of the scraper roller C1 in the adjustment groove C4.2, thereby changing the center distance between the scraper roller C1 and the paint spreading roller B1 and / or the pressure roller B2, and thus precisely controlling the contact gap and contact pressure between them. This gap adjustment method is characterized by its simple structure, intuitive operation, and rapid response. Its technical effects are: it can effectively control the scraping force of the scraper roller C1 on the surface of the working roller, thereby achieving fine management of the amount of paint on the paint spreading roller B1 and / or the pressure roller B2; by adjusting the gap between the scraper roller C1 and the working roller, the thickness of the scraped paint can be precisely controlled, thereby adjusting the amount of paint finally carried on the surface of the working roller, ensuring the uniformity of paint distribution in the roller axis; at the same time, this adjustment method also provides flexible process adaptability for paints with different viscosities and solid contents, and the operator can quickly adjust according to the actual coating effect, further improving coating uniformity and product quality stability.

[0074] In addition, a rotation limiting part is provided between the swing block C4 and the paint scraper roller C1. This rotation limiting part can be a limiting protrusion or limiting block fixedly mounted on the swing block C4, or it can be a detachable swing block limiting part C4.1, and a limiting protrusion or limiting block fixedly mounted on the paint scraper roller C1, or it can be a detachable paint scraper roller limiting part C1.1. When the paint scraper roller C1 rotates to a certain position, its paint scraper roller limiting part C1.1 abuts against the swing block limiting part C4.1, thereby limiting further rotation of the paint scraper roller C1. Through the limiting cooperation between the paint scraper roller limiting part C1.1 and the swing block limiting part C4.1, the operator can selectively allow or restrict the rotation of the paint scraper roller C1. When the scraper roller C1 is allowed to rotate, it forms a rolling engagement with the paint spreading roller B1 and / or the pressure roller B2 to achieve a gentle scraping effect. When the scraper roller C1 is restricted from rotating, it forms a friction engagement with the paint spreading roller B1 and / or the pressure roller B2, which can provide a stronger scraping force to cope with different paint properties and process requirements, thereby achieving flexible adjustment of the coating amount.

[0075] A paint supply pipe 200 is provided on the paint scraper roller bracket C2. The paint supply pipe 200 extends in a direction perpendicular to the conveyor 100 and is located in the upper region between the paint spreading roller B1 and the paint pressing roller B2.

[0076] In this embodiment, one end of the paint supply pipe 200 is closed or connected to a circulation loop, and the other end is connected to the paint pump and paint container via a hose. Multiple precision-machined discharge holes (or nozzles) are evenly distributed axially along the pipe body. Its installation position is carefully designed, fixed to the scraper roller bracket C2 by pipe clamps, and located in the area above the area between the spreading roller B1 and the pressing roller B2, with the discharge holes precisely facing the wedge-shaped gap between the two rollers (i.e., above the closest point of the two rollers). During operation, the paint pump delivers paint to the paint supply pipe 200 at a stable pressure and flow rate. The paint drips or sprays evenly from the multiple discharge holes onto the gap or surface between the spreading roller B1 and the pressing roller B2. The relative rotation of the two rollers evenly distributes the paint and forms a stable material bridge, achieving uniform feeding.

[0077] The paint supply pipe 200 is mounted on the scraper roller bracket C2, integrating the feeding and scraping functions into a single component. This results in a compact structure, saves installation space, and ensures that the relative positions of the feeding point and the scraping point are fixed. Simultaneously, the paint supply pipe 200, located between the spreading roller B1 and the pressing roller B2, allows the paint to quickly enter the roller gap, reducing the contact time between the paint and air, delaying solvent evaporation and surface skinning, and improving the stability of the coating quality. For a circulating supply system, excess paint can flow back along the roller gap, forming a stable cycle.

[0078] The outer surface of the paint spreading roller B1, the paint pressing roller B2, or the paint scraping roller C1 has a certain degree of flexibility. Specifically, the paint spreading roller B1, the paint pressing roller B2, or the paint scraping roller C1 can be made with a metal core, and then the outer surface can be covered with a soft material to achieve a soft surface. Alternatively, the paint spreading roller B1, the paint pressing roller B2, or the paint scraping roller C1 can also be made entirely of a soft material for the core, which also achieves a soft surface.

[0079] Specifically, in this embodiment, the paint-applying roller B1, the paint-pressing roller B2, and the paint-scraping roller C1 are all made of steel or aluminum cores. The outer surface of the paint-applying roller B1 is covered with a flexible material. This flexible material can be a synthetic rubber (such as nitrile rubber NBR or polyurethane rubber PU) with a certain degree of hardness and elasticity, or it can be silicone, felt, or a special polymer material. The covering thickness is typically 5-15 mm, and the Shore hardness is selected between A30 and A90 according to process requirements. The flexible material is tightly bonded to the paint-applying roller B1 through high-temperature vulcanization or a special bonding process, and is precision ground to ensure dimensional accuracy and surface finish. After being covered with a flexible component, the contact between the paint spreading roller B1 and the workpiece becomes elastic, which better adapts to minor unevenness on the workpiece surface (such as the conduits of solid wood, the slight bumps and dents of medium-density fiberboard, and minor scratches on metal plates), preventing the rigid roller from damaging the workpiece surface. This is especially suitable for surface-sensitive materials. At the same time, the elastic deformation increases the contact area between the paint spreading roller B1 and the workpiece, forming a wider pressure zone, improving paint transfer efficiency and coating uniformity. Moreover, the contact between the paint spreading roller B1 and the scraping roller C1 through the flexible component allows for a gentler scraping action, creating a "soft scraping" effect, further reducing potential wear on the surface of the paint spreading roller B1. The flexible material also better conforms to the surface of the working roller, improving the thoroughness of the scraping. In addition, the flexible component has a certain shock absorption and noise reduction capability, which can reduce equipment operating noise and improve the comfort of the working environment. Selecting flexible components with different hardnesses can also adapt to the requirements of paints with different viscosities and different coating pressures.

[0080] In this embodiment, the paint scraping roller C1 preferably rotates and abuts against the outer periphery of the paint spreading roller B1, and its rotational abutment position is optimized. Specifically, there are two preferred positions: one is located on the central axis D of the paint spreading roller B1; the other is located between the central axis D of the paint spreading roller B1 and the paint pressing roller B2. When the scraping point is set on the central axis, the force exerted by the scraping roller C1 on the coating roller B1 passes through the center of the roller, resulting in the most balanced force. This avoids generating additional torque on the rotation of the coating roller B1, which helps maintain the smoothness of the rotation and the lifespan of the bearings. When the scraping point is set between the central axis and the pressure roller B2, the scraping position is closer to the coating area (i.e., the pressure zone) formed by the coating rollers B1 and B2. This allows for final precise leveling and metering of the paint before it is transferred to the workpiece. At this point, the scraped paint is partially distributed but not yet fully transferred, resulting in more precise control. Furthermore, the scraped old paint is more likely to fall off or flow along the surface of the scraping roller C1 to the recycling device below under the influence of gravity and centrifugal force, preventing it from re-contaminating the effective working area of ​​the coating roller. By optimizing the position of the paint scraping contact point, the paint scraping effect can be guaranteed while also taking into account the balance of roller force and the convenience of waste paint diversion. The selection can be made according to different process priorities (more emphasis on roller stability or more emphasis on paint scraping accuracy), which further improves the practicality and process adaptability of the paint scraping device.

[0081] To prevent paint from accumulating at the ends of the rollers and leaking into the bearings, frame, and other components at both ends of the rollers, causing contamination, bearing jamming, or corrosion, the coating device B is also equipped with an end guide groove B3.

[0082] In this embodiment, the end guide groove B3 is a long, narrow groove structure, formed by stamping or bending stainless steel plate, which is corrosion-resistant and easy to clean. It is located at the end of the paint spreading roller B1 and / or the paint pressing roller B2, with its groove opening precisely facing the roller end face, maintaining a minimal gap. An end scraper B4 is provided on the end guide groove B3. The end scraper B4 is made of a wear-resistant, solvent-resistant, low-friction coefficient flexible material (such as polytetrafluoroethylene (PTFE) or ultra-high molecular weight polyethylene (UHMW-PE). Its cutting edge is pressed tightly against the end face of the paint spreading roller B1 and / or the paint pressing roller B2 by the pressure generated by a spring or its own elastic deformation. When the rollers rotate, the end scraper B4 scrapes off the paint accumulated at the roller end due to centrifugal force and surface tension, guiding it along the scraper's inclined surface into the end guide groove B3, and then discharging it to the recycling system through the drainage hole or conduit at the bottom of the guide groove. This effectively prevents paint from leaking along the roller end face to critical components such as the roller bearing housing, bearing, and frame, avoiding bearing jamming, accelerated wear, or corrosion due to paint contamination, and greatly extending the service life of the bearing and roller. At the same time, it prevents paint from accidentally dripping onto the conveyor 100 or the edge of the workpiece, keeping the equipment and workpiece clean and avoiding quality defects and subsequent grinding work caused by excess paint drying on the workpiece edge. The end scraper B4 is made of flexible and wear-resistant material, which will not damage the finished surface of the end face of the paint spreading roller B1 and / or the paint pressing roller B2, ensuring long-term reliability and scraping effect.

[0083] The coating unit B also includes a paint roller support B6. The paint roller support B6, serving as the skeleton of the coating unit B, is a precision-welded rectangular frame structure with sufficient strength and rigidity. It is fixedly mounted on the lifting slide plate of the lifting device A, connected by multiple high-strength bolts, and moves precisely with the lifting device. An end guide trough support B5 is installed on the end guide trough B3. The end guide trough B3 is bolted to the end guide trough support B5, which in turn is bolted to the side of the paint roller support B6. This modular installation method facilitates the individual disassembly, cleaning, and blade replacement of the end guide trough B3 without disassembling the entire coating unit, greatly improving the maintainability and cleaning convenience of the equipment.

[0084] The drive system includes a paint distribution roller driver B7 and a paint pressing roller driver B8, which are respectively located on the same side or both sides of the paint distribution roller support B6 (depending on the spatial layout) and are each connected to a reducer (usually a high-precision planetary reducer or worm gear reducer to increase torque and ensure speed stability). The output shafts of the paint distribution roller driver B7 and the paint pressing roller driver B8 are connected to the input shafts of the corresponding reducers via high-elasticity couplings to absorb vibration and compensate for coaxiality errors. The output shafts of the reducers are then connected to the end drive shafts of the paint distribution roller B1 and the paint pressing roller B2 via shrink sleeves (keyless connection, easy to disassemble and assemble) or key connections. This independent drive design allows for precise and independent control of the speed and direction of the two rollers. By adjusting the speed ratio between the two rollers, the amount and effect of paint transfer (such as clockwise or counterclockwise transfer) can be precisely controlled to adapt to the process requirements of different paint viscosities, different coating amounts, and different surface effects. At the same time, the use of reducers increases the output torque, ensuring stable, stepless speed-changing operation under viscous paint loads.

[0085] The conveyor 100 is equipped with a paint recovery box 300 and an inclined recovery trough 400 for recovering paint from the paint spreading roller B1 and the paint pressing roller B2. The paint recovery box 300 is an open-top box made of stainless steel, located directly below the end guide trough B3, and is used to collect paint discharged from the guide holes of the end guide trough B3. The inclined recovery trough 400 is a long, narrow V-shaped or U-shaped trough mounted on the frame, located below the area between the paint spreading roller B1 and the paint pressing roller B2, covering the entire length of the rollers. It is used to collect paint that drips, is thrown out, or is scraped off by the paint scraping roller C1 from the area between the paint spreading roller B1 and the paint pressing roller B2. The side of the paint recovery box 300 facing the inclined recovery trough 400 has an inclined surface or guide pipe, which automatically guides the collected paint to the inclined recovery trough 400 below. The inclined recovery trough 400 is inclined outwards from the conveyor 100 along its length (the inclination angle is typically 3-10° to ensure the paint flows by gravity), and a movable paint collection component (such as a covered paint bucket or container) is installed at its lower inclined end. The entire paint recovery system utilizes gravity to automatically collect the paint recovered from various points (ends, middle) into the final collection component, requiring no additional power unit (such as a pump). This system is energy-efficient and absolutely reliable. It achieves effective paint recovery and centralized processing, reducing paint waste and environmental pollution, and meets green manufacturing and environmental protection requirements. Simultaneously, the rational layout and flow guidance design of the paint recovery box 300 and the inclined recovery trough 400 prevents disorderly accumulation and dripping of paint on various internal components, greatly simplifying daily cleaning, improving production efficiency and operational safety, and maintaining a clean work site.

[0086] The above describes the preferred embodiments of the present invention, illustrating and describing the basic principles, main features, and advantages of the invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as defined by the appended claims and their equivalents.

Claims

1. A roll coating method characterized by, Includes the following steps: The scraper roller (C1) is rotated to press against the surface of the coating roller (B1) and / or the pressure roller (B2) that has already been coated, so that the scraper roller (C1) removes the old paint residue on the surface of the coating roller (B1) and / or the pressure roller (B2) through rotational contact. The paint spreading roller (B1) and / or the paint pressing roller (B2) after the old paint has been removed are reused for the coating operation, and new paint is supplied to the surface of the paint spreading roller (B1) and / or the paint pressing roller (B2); A coating cycle is completed by transferring new paint to the surface of the workpiece through a paint spreading roller (B1) and / or a paint pressing roller (B2).

2. The roller coating method according to claim 1, characterized in that: It also includes the step of adjusting the overall height of the paint spreading roller (B1) and the paint pressing roller (B2) by means of the lifting device (A) so that the paint spreading roller (B1) and the workpiece surface maintain a preset coating gap.

3. The roller coating method according to claim 1 or 2, characterized in that: The rotation method by which the paint scraper roller (C1) removes residual old paint is as follows: The scraper roller (C1) achieves driven rotation by contact with the surfaces of the paint spreading roller (B1) and / or the paint pressing roller (B2), and generates a constant scraping force by utilizing the opposite directions of their motion; or, the scraper roller (C1) is driven to rotate actively by an independent driver, and the scraping force is adjusted by controlling whether the rotation direction between the scraper roller (C1) and the paint spreading roller (B1) and / or the paint pressing roller (B2) is the same or opposite.

4. The roller coating method according to claim 1 or 2, characterized in that: It also includes the step of adjusting the working mode of the paint scraper roller (C1), controlling the rotation state of the paint scraper roller (C1) by rotating the limiting part, so as to select the matching mode between the paint scraper roller (C1) and the paint spreading roller (B1) and / or the paint pressing roller (B2); When the rotation limiting part is in the non-limited state, the paint scraper roller (C1) is allowed to rotate, and the paint scraper roller (C1) forms a rolling engagement with the paint spreading roller (B1) and / or the paint pressing roller (B2); when the rotation limiting part is in the limited state, the paint scraper roller (C1) is restricted from rotating, and the paint scraper roller (C1) forms a friction engagement with the paint spreading roller (B1) and / or the paint pressing roller (B2).

5. The roller coating method according to claim 3, characterized in that: It also includes the step of adjusting the contact pressure between the scraper roller (C1) and the spreader roller (B1) and / or the pressure roller (B2) before removing residual old paint: The connecting shaft (C3) is driven to rise and fall by the paint scraper roller adjustment assembly (C5). The connecting shaft (C3) drives the swing block (C4) and the paint scraper roller (C1) installed on the swing block (C4) to rise and fall together, so as to set the optimal paint scraping pressure. Alternatively, the paint scraping roller (C1) rotates on the swing block (C4) and moves along the trajectory of the adjustment groove (C4.2) on the swing block (C4).

6. The roller coating method according to claim 1, characterized in that: It also includes the step of squeezing and spreading the new paint on the surface of the paint spreading roller (B1) by the relative rotation of the pressure roller (B2) and the spreading roller (B1) after removing the residual old paint, so that the new paint is evenly distributed on the surface of the spreading roller (B1).

7. The roller coating method according to claim 1, characterized in that: It also includes the step of cleaning the paint buildup at the ends of the paint spreading roller (B1) and / or the paint pressing roller (B2) while removing residual old paint: The old paint residue remaining at the ends of the paint roller (B1) and / or the pressure roller (B2) is scraped off by the end scraper blade (B4), and the scraped paint is discharged through the end guide groove (B3).

8. The roller coating method according to claim 7, characterized in that: It also includes the step of recycling the removed old paint: The old paint discharged from the roller surface and / or end guide trough (B3) during the cleaning process is collected into the paint collection unit through the paint recycling box (300) and the inclined recycling trough (400).

9. A roller coating device, characterized in that: The roller coating method according to any one of claims 1 to 7, wherein the roller coating equipment comprises: Conveyor (100), used for conveying workpieces; The coating device (B) includes a paint spreading roller (B1), a paint pressing roller (B2) and a driver. The paint spreading roller (B1) and the paint pressing roller (B2) are arranged back and forth along the conveying direction of the conveyor (100) and are driven to rotate relative to each other by the driver. The paint spreading roller (B1) is used to transfer paint to the surface of the workpiece. A circumferential paint scraping device (C) is provided on the paint spreading roller (B1) and / or the paint pressing roller (B2), including a paint scraping roller (C1). After completing one coating, the paint scraping roller (C1) rotates and abuts against the surface of the paint spreading roller (B1) and / or the paint pressing roller (B2) to remove the old paint residue on the surface of the paint spreading roller (B1) and / or the paint pressing roller (B2). Lifting device (A) is installed on conveyor (100) and driven to coating device (B), used to drive coating device (B) to lift as a whole to adjust coating height.

10. The roller coating equipment according to claim 9, characterized in that: The circumferential paint scraping device (C) also includes a paint scraping roller bracket (C2), which is mounted on the coating device (B); the paint scraping roller (C1) is directly rotatably connected to the paint scraping roller bracket (C2), or the paint scraping roller (C1) is rotatably connected to the paint scraping roller bracket (C2) through a swing mechanism, the swing mechanism including a connecting shaft (C3) rotatably mounted on the paint scraping roller bracket (C2) and a swing block (C4) fixed on the connecting shaft (C3), the paint scraping roller (C1) being rotatably connected to the swing block (C4); The paint scraper roller bracket (C2) is also provided with a paint scraper roller adjustment component (C5), which is driven to connect to the connecting shaft (C3) to drive the connecting shaft (C3) to rise and fall and drive the swing block (C4) and the paint scraper roller (C1) to rise and fall, so as to adjust the abutment pressure of the paint scraper roller (C1). The coating device (B) further includes a fixedly installed end guide groove (B3) and an end scraper (B4) installed on the end guide groove (B3). The end guide groove (B3) is located at the end of the paint spreading roller (B1) and / or the paint pressing roller (B2). The end scraper (B4) abuts against the end face of the paint spreading roller (B1) and / or the paint pressing roller (B2) to remove paint accumulation at the end. The conveyor (100) is equipped with a paint recycling box (300) and an inclined recycling trough (400). The paint recycling box (300) is located below the end guide trough (B3), and the inclined recycling trough (400) is located in the area below the paint spreading roller (B1) and the paint pressing roller (B2) for recycling the old paint 2 that has been removed.

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