A color box printing quality inspection device

Abstract

This invention belongs to the field of sensor detection technology, and specifically relates to a color box printing quality inspection device, including a U-shaped bracket, an electric actuator, an industrial inspection camera, a negative pressure suction assembly, a precision positioning assembly, a light-shielding and sealing assembly, a material transfer assembly, a fixed rotation assembly, and an optical supplementary lighting unit. This invention isolates stray light and stabilizes imaging illumination by completely sealing the cylindrical color box to block light, and automatically corrects the position with an arc-shaped positioning plate. It also employs a detection method that uses the color box to rotate and the camera to fix itself, ensuring uniformity of the optical path and imaging. Furthermore, 360° non-contact negative pressure dust removal is performed before inspection, effectively eliminating problems such as ambient light interference, curved surface reflection, imaging distortion, and false detections due to external impurities, significantly improving detection accuracy, stability, and consistency.

Description

Technical Field

[0001] This invention belongs to the field of sensor detection technology, and in particular relates to a color box printing quality detection device. Background Technology

[0002] As the core visual carrier and outer packaging of a product, the printing quality of color boxes directly affects consumers' brand perception and purchasing decisions. This is especially true in high-end daily chemicals, 3C electronics, food and pharmaceuticals, and luxury goods sectors, where printing defects can directly lead to customer rejection, damage to brand reputation, and economic losses. Furthermore, color box printing in industries such as food and pharmaceuticals must comply with mandatory national standards such as GB / T7934-2013 and GB18585-2001. Exported products must also meet international regulations such as EU REACH and US FDA, with strict full-inspection requirements for barcode levels, text information, and printing precision.

[0003] With the development of the packaging industry, cylindrical color boxes are widely used in the packaging of products such as tea, wine, cosmetics, and gifts due to their beautiful shape, comfortable grip, and good sealing properties. However, the continuous curved surface structure of cylindrical color boxes brings many technical challenges to printing quality inspection: 1. When conventional planar industrial cameras photograph cylinders, the image in the middle is normal, but there is severe perspective distortion on the curved surfaces on both sides. The text and patterns are distorted and cannot be accurately compared with the standard template, resulting in large errors in size detection and defect identification. Minor defects such as overprinting deviation and blurry small characters are difficult to detect. 2. Cylindrical color boxes made of materials such as laminated, glossy, gold and silver cardboard, and laser hot stamping have strong specular reflection characteristics. The curved surface will form multi-angle diffuse reflection and directional strong reflection, which can easily cause local overexposure, bright spots and glare, and cover up minor defects. At the same time, the natural light in the workshop, the overhead lights and the stray light from the surrounding equipment will cause uneven dynamic lighting, leading to a surge in the algorithm's misjudgment rate. 3. Existing automated inspection solutions use multiple cameras arranged around the camera or rotating the camera for inspection. The former has high equipment costs and large splicing errors, while the latter has problems such as rotational jitter, focal length drift, and optical path fluctuations, resulting in poor imaging stability. Furthermore, the latter has a complex structure and is difficult to maintain, making it difficult to adapt to the needs of high-speed production lines. Summary of the Invention

[0004] The purpose of this invention is to address the above-mentioned problems by providing a color box printing quality inspection device.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a color box printing quality inspection device, including a U-shaped bracket, an electric push rod, an industrial inspection camera, a negative pressure suction component, a precision positioning component, a light-shielding and sealing component, a material transfer component, a fixed rotation component, and an optical supplementary lighting unit; The electric actuator is fixedly installed on the horizontal part of the U-shaped bracket, and its lower movable end is connected to a lifting circular plate. The industrial inspection camera and the negative pressure suction assembly are symmetrically fixed at the lower end of the lifting circular plate. The industrial inspection camera is used to collect printed images of the periphery of the cylindrical color box, and the negative pressure suction assembly is used to remove dust and impurities from the surface of the cylindrical color box. The precise positioning component is horizontally fixed on the U-shaped bracket and is used to perform positioning and calibration on the cylindrical color box to be inspected. The light-shielding and sealing assembly is installed on the lifting circular plate to form a closed detection space during detection; The material transfer assembly is located inside the U-shaped bracket and is used to transport cylindrical color boxes; The fixed rotating component is installed inside the material transfer component and is used to adsorb and fix the cylindrical color box and drive it to rotate at a uniform speed.

[0006] Furthermore, the negative pressure suction assembly includes a suction cylinder fixed to the lower end of the lifting circular plate. Multiple negative pressure suction heads are evenly connected to the side wall of the suction cylinder. A suction pipe is connected to the rear side of the suction cylinder. A suction pump and a filter box are installed on the suction pipe. Both the suction pump and the filter box are fixed to the outer wall of the suction cylinder.

[0007] Furthermore, the precision positioning component includes two symmetrically fixed electric actuators inserted into the U-shaped bracket. The electric actuators are horizontally positioned, and an arc-shaped positioning plate is fixed to the moving end of the electric actuator. The arc of the arc-shaped positioning plate matches the arc of the outer surface of the cylindrical color box, and both inner sides of the arc-shaped positioning plate are set with inclined guide structures.

[0008] Furthermore, the light-shielding sealing assembly includes multiple electric push rods three that are fixedly inserted into the lifting circular plate in a ring-shaped arrangement. The lower moving ends of the multiple electric push rods three are fixed with the same ring-shaped moving plate. An elastic folding light-shielding sleeve is fixed between the ring-shaped moving plate and the lifting circular plate. The elastic folding light-shielding sleeve is set outside the industrial inspection camera and the negative pressure suction assembly.

[0009] Furthermore, the material transfer assembly includes an electric roller assembly with two conveyor belts wound around it. A gap is left between the two conveyor belts. A support frame is also provided on the inner side of the two conveyor belts. A fixed rotating component is provided on the support frame at the position corresponding to the gap between the two conveyor belts.

[0010] Furthermore, the fixed rotating assembly includes a U-shaped mounting plate fixed to the lower end of the horizontal part of the support frame. A negative pressure pipe is rotatably sleeved on the horizontal part of the U-shaped mounting plate. An adsorption shell is fixedly connected to the upper end of the negative pressure pipe. The support frame has a through hole for the adsorption shell to extend through. The adsorption shell is disposed between the two conveyor belts. Multiple negative pressure suction holes are opened on the upper end face of the adsorption shell. A vacuum pump is fixed to the lower end of the U-shaped mounting plate. The air inlet of the vacuum pump is rotatably connected to the lower end of the negative pressure pipe through a rotary sealing joint. A motor drive assembly for driving the negative pressure pipe to rotate around its own axis is fixed to the inner side of the U-shaped mounting plate.

[0011] Furthermore, the optical supplementary lighting unit is fixedly installed on the lower end face of the lifting circular plate and located next to the industrial inspection camera to provide uniform and stable illumination for inspection.

[0012] Furthermore, the optical supplementary lighting unit includes two strip LED light sources symmetrically arranged on both sides of the industrial inspection camera. The illumination angle of the strip LED light sources is adjustable and forms an angle of 30° to 45° with the lens of the industrial inspection camera.

[0013] Compared with existing technologies, the advantages of this invention are as follows: 1. By setting up a light-shielding and sealing component, the cylindrical color box is completely enclosed, completely isolating the stray light in the workshop environment, eliminating dynamic light interference, and completely blocking external light sources such as factory ceiling lights, natural light from windows, reflected light from surrounding equipment, and stray light from personnel operation. This makes the detection area an independent, sealed, and light-free environment, fundamentally solving the problems of image brightness fluctuations and chaotic light and shadow caused by changes in ambient light intensity and angle. It ensures that the lighting conditions for each frame of imaging are completely consistent, realizes controllable light source, and significantly reduces the problems of high reflectivity and overexposure on curved surfaces.

[0014] 2. Through the set precise positioning components, the arc-shaped positioning plate can automatically correct the position of the color box, ensuring the stability of the image matching algorithm and good consistency between batches.

[0015] 3. The inspection method adopts a combination of a cylindrical color box rotation and a fixed industrial inspection camera. The camera, light source and optical path system are stationary throughout the process, and the imaging focal length, shooting angle and lighting conditions are completely unified, which effectively avoids the shaking, distortion and image quality degradation caused by camera rotation.

[0016] 4. The negative pressure suction component removes external impurities such as paper fibers and dust from the surface of the color box in 360° without dead angles before detection, avoiding misjudgment of impurities as printing defects, reducing the probability of false detection and missed detection. At the same time, it is adapted to the cylindrical arc circumferential structure to achieve non-contact full-area cleaning, preventing surface scratches and light interference caused by impurities, and ensuring stable and uniform image quality in a closed and light-proof environment. Attached Figure Description

[0017] Figure 1 This is a three-dimensional structural diagram of the entire invention; Figure 2 This is a three-dimensional structural diagram of the U-shaped bracket of the present invention; Figure 3 This is a three-dimensional structural schematic diagram of the negative pressure suction component of the present invention; Figure 4 This is a three-dimensional structural schematic diagram of the light-shielding and sealing component of the present invention; Figure 5 This is a three-dimensional structural schematic diagram of the material transfer component of the present invention; Figure 6 This is a three-dimensional structural diagram of the fixed rotating component of the present invention.

[0018] In the diagram: 1. U-shaped bracket, 2. Electric actuator one, 3. Lifting circular plate, 4. Industrial inspection camera, 5. Negative pressure suction assembly, 51. Suction cylinder, 52. Negative pressure suction head, 53. Suction pipe, 54. Suction pump, 55. Filter box, 6. Precision positioning assembly, 61. Electric actuator two, 62. Arc-shaped positioning plate, 7. Light-shielding sealing assembly, 71. Electric actuator three, 72. Circular moving plate, 73. Elastic folding light-shielding sleeve, 8. Material transfer assembly, 81. Electric roller group, 82. Conveyor belt, 83. Support frame, 9. Fixed rotation assembly, 91. U-shaped mounting plate, 92. Negative pressure pipe, 93. Adsorption circular shell, 94. Negative pressure suction hole, 95. Vacuum pump, 96. Motor drive assembly, 10. Optical supplementary lighting unit. Detailed Implementation

[0019] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0020] like Figures 1-6 As shown, a color box printing quality inspection device includes a U-shaped bracket 1. An electric push rod 2 is vertically fixedly installed at the center of the top horizontal part of the U-shaped bracket 1. The electric push rod 2 is a servo electric push rod, and its lower moving end is fixedly connected to a horizontally set lifting circular plate 3 through a flange.

[0021] Industrial inspection cameras 4 and negative pressure suction components 5 are symmetrically fixed on both sides of the lower end face of the lifting circular plate 3. The industrial inspection camera 4 is a 20-megapixel global shutter CMOS industrial camera with a frame rate of 30fps. It is equipped with an 8mm fixed-focus high-definition lens, which can clearly capture minute printing defects at the level of 0.01mm. The lens of the industrial inspection camera 4 is vertically oriented towards the periphery of the cylindrical color box to ensure that the shooting area is the front curved surface of the color box, minimizing perspective distortion.

[0022] The negative pressure suction component 5 is used to remove impurities from the surface of the color box before inspection. Its specific structure is as follows: Figure 3As shown, the device includes a suction cylinder 51 vertically fixed to the lower end face of the lifting circular plate 3. Multiple negative pressure suction heads 52 are evenly connected to the side wall of the suction cylinder 51. The negative pressure suction heads 52 are funnel-shaped to increase the adsorption area. Their suction ports face the peripheral surface of the cylindrical color box, and the distance between the suction port and the surface of the color box is 10mm, which can ensure sufficient adsorption force without contacting and scratching the color box. A suction pipe 53 is connected to the rear side of the suction cylinder 51. A suction pump 54 and a filter box 55 are installed in series on the suction pipe 53. The filter box 55 is equipped with a removable non-woven filter element, which is convenient for regular replacement and prevents dust from entering the suction pump 54 and causing damage.

[0023] Precision positioning components 6 are horizontally fixedly installed on both sides of the vertical section of the U-shaped bracket 1 for centering the color box. Figure 2 As shown, the precision positioning component 6 includes two symmetrical, horizontally fixed electric actuators 61 inserted into the vertical parts on both sides of the U-shaped bracket 1. The electric actuators 61 are also servo-driven, with a positioning accuracy of ±0.1mm. The axes of the two electric actuators 61 are collinear and perpendicular to the conveying direction of the material transfer component 8. An arc-shaped positioning plate 62 is bolted to the moving end of each electric actuator 61. The arc-shaped positioning plate 62 is made of aluminum alloy, and its inner arc surface curvature matches the outer surface curvature of the cylindrical color box to be inspected, allowing it to fit tightly against the box surface. Both ends of the arc-shaped positioning plate 62 have inclined guide structures on their inner sides. When the color box shifts position, the inclined surfaces guide the color box back to its original position.

[0024] A light-shielding sealing component 7 is installed on the lower edge of the lifting circular plate 3 to form a closed detection space during detection, such as... Figure 4 As shown, the light-shielding enclosure component 7 includes multiple electric actuators 71 that are uniformly distributed in a ring and fixedly inserted into the edge of the lifting circular plate 3. The electric actuators 71 are servo electric actuators. The lower moving ends of the multiple electric actuators 71 are fixedly connected to a horizontally set annular moving plate 72. The annular moving plate 72 is made of aluminum alloy. An elastic folding light-shielding sleeve 73 is fixedly connected between the upper end face of the annular moving plate 72 and the lower end face of the lifting circular plate 3. The elastic folding light-shielding sleeve 73 is cylindrical and made of black opaque silicone material. It has good elasticity and light-shielding properties and can completely block external light from entering. The elastic folding light-shielding sleeve 73 completely covers the industrial inspection camera 4, the negative pressure suction component 5, and the optical supplementary light unit 10 inside.

[0025] A material conveying assembly 8 is provided on the inner bottom of the U-shaped support 1 for continuously conveying color boxes, such as... Figure 5As shown, the material transfer assembly 8 includes an electric roller assembly 81, which includes a drive roller, a driven roller, and a motor. The motor is a variable frequency speed control motor, which can adjust the conveying speed according to production needs. Two PU material conveyor belts 82 are wound around the outside of the electric roller assembly 81. The two conveyor belts 82 are arranged in parallel and have a gap of 80mm between them to accommodate the adsorption shell 93 of the fixed rotating assembly 9. A horizontally arranged support frame 83 is provided on the inner side of the two conveyor belts 82 to support the conveyor belts 82 and prevent the belts from sagging. A circular through hole is opened on the support frame 83 at the position corresponding to the gap between the two conveyor belts 82, and the fixed rotating component 9 is arranged below the through hole.

[0026] The fixed rotating component 9 is used to attach and fix the color box from the bottom and drive its rotation. Its specific structure is as follows: Figure 6 As shown, the device includes a U-shaped mounting plate 91 fixed to the lower end of the horizontal section of the support frame 83. A vertical negative pressure pipe 92 is rotatably connected to the center of the horizontal section of the U-shaped mounting plate 91 via a bearing. The upper end of the negative pressure pipe 92 is fixedly connected to a disc-shaped adsorption shell 93. The outer diameter of the adsorption shell 93 is 70mm, which is smaller than the gap width between the two conveyor belts 82. The upper surface of the adsorption shell 93 is evenly provided with 36 negative pressure suction holes 94 with a diameter of 1.5mm, which can generate uniform adsorption force. A vacuum pump 95 is fixedly installed at the lower end of the U-shaped mounting plate 91. Its air inlet is rotatably connected to the lower end of the negative pressure pipe 92 through a rotary sealing joint. The rotary sealing joint can ensure that the negative pressure pipe 92 maintains good sealing during rotation. A motor drive assembly 96 is fixedly installed on the inner side of the U-shaped mounting plate 91. The motor drive assembly 96 drives the negative pressure pipe 92 to drive the adsorption shell 93 and the color box to rotate at a uniform speed. The speed can be steplessly adjusted between 10 and 60 rpm.

[0027] An optical supplementary lighting unit 10 is also fixedly installed on the lower end face of the lifting circular plate 3, and is located next to the industrial inspection camera 4. It is used to provide uniform and stable illumination for inspection. The optical supplementary lighting unit 10 includes two strip LED light sources symmetrically arranged on both sides of the industrial inspection camera 4. The strip LED light sources are diffuse light sources with a color temperature of 6000K and the brightness can be adjusted steplessly. The illumination angle of the two strip LED light sources is 45°, which is symmetrically distributed with the lens of the industrial inspection camera 4. It can provide uniform and soft illumination for the curved surface of the cylindrical color box, effectively reduce high reflectivity and shadows, and improve image quality.

[0028] The operating principle of the present invention is described as follows: The cylindrical color box to be tested is placed on two conveyor belts 82, and the electric roller group 81 drives the conveyor belts 82 to rotate, thereby moving the cylindrical color box into the U-shaped bracket 1. At this time, the electric roller group 81 stops operating. Two electric actuators 61 extend simultaneously, pushing the arc-shaped positioning plates 62 on both sides toward the color box. Under the squeezing and inclined guiding action of the arc-shaped positioning plates 62, the color box is gradually corrected to the center position and coaxial with the suction shell 93 below. After positioning is completed, the electric actuators 61 drive the arc-shaped positioning plates 62 to move back quickly. The electric push rod 2 pushes the lifting circular plate 3 down, so that the industrial inspection camera 4 and the negative pressure suction assembly 5 move to the preset inspection height. At this time, the distance between the lens of the industrial inspection camera 4 and the periphery of the color box is 150mm, and the distance between the negative pressure suction head 52 and the surface of the color box is 10mm. The vacuum pump 95 is started, and a negative pressure is formed in the adsorption shell 93 through the negative pressure tube 92. The adsorption force generated by the negative pressure suction hole 94 firmly fixes the bottom of the color box to the adsorption shell 93, preventing the color box from slipping or shifting during rotation. The suction pump 54 starts and creates a negative pressure in the suction cylinder 51 through the suction pipe 53. The negative pressure suction head 52 quickly adsorbs and removes impurities such as paper fibers, dust, and ink fragments attached to the surface of the color box, and then filters them through the filter box 55. At the same time, the motor drive assembly 96 drives the negative pressure pipe 92 to rotate the color box at a constant speed of 30 rpm for one revolution, achieving 360° dust removal without dead angles. After the dust removal is completed, the suction pump 54 stops working. Multiple electric push rods 71 ​​extend simultaneously, pushing the annular moving plate 72 downward and stretching the elastic folding light-shielding rubber sleeve 73 until the lower end of the annular moving plate 72 is tightly attached to the upper surface of the conveyor belt 82. At this time, the elastic folding light-shielding rubber sleeve 73 completely seals the industrial inspection camera 4 and the color box, forming an independent light-free inspection space. The optical supplement unit 10 next to the industrial inspection camera 4 is turned on to provide uniform illumination for inspection. The motor drive component 96 continues to drive the color box to rotate at a constant speed of 20 rpm. The industrial inspection camera 4 continuously acquires printed images of the color box at a frame rate of 30 fps. The acquired images are transmitted to the industrial computer through the image acquisition card. After image preprocessing and distortion correction, the images are compared with the pre-stored standard template at the pixel level, and printing defects are identified through the AI ​​defect recognition model.

[0029] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A color box printing quality inspection device, comprising a U-shaped support (1), characterized in that, It also includes an electric actuator (2), an industrial inspection camera (4), a negative pressure suction assembly (5), a precision positioning assembly (6), a light-shielding and sealing assembly (7), a material transfer assembly (8), a fixed rotation assembly (9), and an optical supplementary lighting unit (10). The electric push rod (2) is fixedly installed on the horizontal part of the U-shaped bracket (1), and its lower movable end is connected to the lifting circular plate (3). The industrial inspection camera (4) and the negative pressure suction assembly (5) are symmetrically fixed at the lower end of the lifting circular plate (3). The industrial inspection camera (4) is used to collect printed images on the periphery of the cylindrical color box, and the negative pressure suction assembly (5) is used to remove dust and impurities from the surface of the cylindrical color box. The precision positioning component (6) is horizontally fixed on the U-shaped bracket (1) and is used to perform positioning correction on the cylindrical color box to be tested; The light-shielding sealing component (7) is installed on the lifting circular plate (3) to form a closed detection space during detection; The material transfer assembly (8) is located inside the U-shaped bracket (1) and is used to transport cylindrical color boxes; The fixed rotating component (9) is installed inside the material transfer component (8) and is used to adsorb and fix the cylindrical color box and drive it to rotate at a constant speed.

2. The color box printing quality inspection device according to claim 1, characterized in that, The negative pressure suction assembly (5) includes a suction cylinder (51) fixed at the lower end of the lifting circular plate (3). Multiple negative pressure suction heads (52) are evenly connected to the side wall of the suction cylinder (51). A suction pipe (53) is connected to the rear side of the suction cylinder (51). A suction pump (54) and a filter box (55) are installed on the suction pipe (53). The suction pump (54) and the filter box (55) are both fixed to the outer wall of the suction cylinder (51).

3. The color box printing quality inspection device according to claim 1, characterized in that, The precision positioning component (6) includes two symmetrically fixed electric push rods (61) inserted into the U-shaped bracket (1). The electric push rods (61) are horizontally arranged, and an arc-shaped positioning plate (62) is fixed at the moving end of the electric push rods (61). The arc of the arc-shaped positioning plate (62) matches the arc of the outer surface of the cylindrical color box, and the inner sides of both ends of the arc-shaped positioning plate (62) are set as inclined guide structures.

4. The color box printing quality inspection device according to claim 1, characterized in that, The light-shielding sealing assembly (7) includes multiple electric push rods (71) arranged in a ring and fixedly inserted on the lifting circular plate (3). The lower moving ends of the multiple electric push rods (71) are fixed with the same annular moving plate (72). An elastic folding light-shielding sleeve (73) is fixed between the annular moving plate (72) and the lifting circular plate (3). The elastic folding light-shielding sleeve (73) is set outside the industrial inspection camera (4) and the negative pressure suction assembly (5).

5. The color box printing quality inspection device according to claim 1, characterized in that, The material transfer assembly (8) includes an electric roller assembly (81), with two conveyor belts (82) wound around the electric roller assembly (81). There is a gap between the two conveyor belts (82), and a support frame (83) is provided on the inner side of the two conveyor belts (82). A fixed rotating assembly (9) is provided on the support frame (83) at the position corresponding to the gap between the two conveyor belts (82).

6. The color box printing quality inspection device according to claim 5, characterized in that, The fixed rotating assembly (9) includes a U-shaped mounting plate (91) fixed at the lower end of the horizontal part of the support frame (83). The horizontal part of the U-shaped mounting plate (91) is rotatably sleeved with a negative pressure pipe (92). The upper end of the negative pressure pipe (92) is fixedly connected to an adsorption shell (93). The support frame (83) has a through hole for the adsorption shell (93) to extend through. The adsorption shell (93) is set between two conveyor belts (82). The upper end face of the adsorption shell (93) has multiple negative pressure suction holes (94). The lower end of the U-shaped mounting plate (91) is fixed with a vacuum pump (95). The air inlet of the vacuum pump (95) is rotatably connected to the lower end of the negative pressure pipe (92) through a rotary sealing joint. The inner side of the U-shaped mounting plate (91) is fixed with a motor drive assembly (96) for driving the negative pressure pipe (92) to rotate around its own axis.

7. The color box printing quality inspection device according to claim 1, characterized in that, The optical supplement unit (10) is fixedly installed on the lower end face of the lifting circular plate (3) and located next to the industrial inspection camera (4) to provide uniform and stable illumination for inspection.

8. The color box printing quality inspection device according to claim 7, characterized in that, The optical supplementary lighting unit (10) includes two strip LED light sources symmetrically arranged on both sides of the industrial inspection camera (4). The illumination angle of the strip LED light sources is adjustable and forms an angle of 30° to 45° with the lens of the industrial inspection camera (4).

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