A paper product label pre-printing treatment device

Abstract

The present application relates to paper product pretreatment technical field, especially to a kind of paper product label prepress pretreatment device, including mounting bracket, hollow main shaft and segmented roller surface assembly, the hollow main shaft inside is provided with for the local radial jacking of segmented roller surface assembly to compensate the radial expansion adjustment mechanism of web tension, the radial expansion adjustment mechanism includes the center driving rod for providing axial actuating force, the mounting bracket is also provided with the driving mechanism for driving center driving rod axial reciprocating motion in rotating state.The present application solves the industry pain points that segmented roll is easy to clip paper and easy to enter dust by labyrinth step cooperation structure, effectively prolongs equipment maintenance cycle, at the same time, by double anti-rotation design and follow-up type hydraulic drive mechanism, effectively ensure the stability of adjustment action under high-speed rotation, avoid the wear and heating caused by relative sliding.

Description

Technical Field

[0001] This invention relates to the field of paper product pretreatment technology, and in particular to a pre-printing pretreatment device for paper product labels. Background Technology

[0002] In the printing and lamination process of paper product labels, the flatness and surface tension uniformity of the paper roll directly affect the printing registration accuracy and yield rate. Due to the influence of the raw paper production process or storage humidity, wide-width paper rolls often have defects such as "ruffled edges" or "tight edges".

[0003] Existing paper machine tension control mechanisms, such as the one disclosed in CN205973179U, often employ a device that adjusts the wrap angle and tension by changing the position of the feed roller. While this device addresses paper breakage to some extent, it suffers from several significant drawbacks: First, the feed roller in this mechanism is a rigid, integral roller, which can only adjust the average tension of the entire sheet of paper. When the paper experiences a "tight edge," the edges remain loose while the center remains taut, failing to compensate for uneven tension across the width. Second, this device often uses an external cylinder to move the bearing housing, resulting in a slow response time. Furthermore, at high speeds (e.g., above 300 m / min), the cantilever structure is prone to vibration, leading to ghosting in the printing. Finally, existing adjustable spreader rollers (such as curved rollers or differential shafts) typically have large mechanical clearances, allowing paper dust and ink particles to easily penetrate the bearings, causing jamming or adjustment failure. Summary of the Invention

[0004] The purpose of this invention is to solve the problems in the prior art, such as the inability of the guide roller to accurately perform segmented tension compensation, the susceptibility of the mechanical structure to dust contamination, and the instability of adjustment under high-speed rotation. Therefore, this invention proposes a pre-processing device for paper product labels.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: A pre-processing device for paper product labels includes a mounting bracket, a hollow main shaft, and a segmented roller assembly. The hollow main shaft is provided with a radial expansion adjustment mechanism for locally radially lifting the segmented roller assembly to compensate for the tension of the roll surface. The radial expansion adjustment mechanism includes a central drive rod for providing axial actuation force. The mounting bracket is also provided with a drive mechanism for driving the central drive rod to perform axial reciprocating motion in a rotating state.

[0006] Preferably, the segmented roller assembly is coaxially sleeved outside the hollow main shaft, the central drive rod is coaxially movably installed inside the hollow main shaft, and the segmented roller assembly is driven to produce radial deformation by the axial displacement of the central drive rod. One end of the hollow main shaft is rotatably mounted on the mounting bracket, the mounting bracket has a U-shaped structure, and several radial guide holes are opened on the side wall of the hollow main shaft.

[0007] Preferably, the radial expansion adjustment mechanism includes a multi-stage cam structure fixed on the central drive rod, an ejector slidably installed in the radial guide hole, the multi-stage cam structure having several conical drive surfaces, and the bottom end of the ejector having a driven inclined surface that abuts against the conical drive surfaces. The driven inclined surface is used to convert the axial force of the central drive rod into a radial lifting force.

[0008] Preferably, an elastic reset member is fixedly provided between the ejector and the hollow main shaft. The elastic reset member is configured to apply a biasing force pointing towards the axis to the ejector and ensure that the ejector and the tapered drive surface always maintain transmission contact. The ejector consists of a slide rod that is slidably connected to the radial guide hole and an arc-shaped abutment block fixed at the top of the slide rod for abutting against the segmented roller surface assembly. The driven inclined surface is machined at the bottom of the slide rod.

[0009] Preferably, the segmented roller assembly is formed by axially stacking several independent roller rings, and the mating end faces of two adjacent independent roller rings are provided with a labyrinth-type stepped mating structure. The labyrinth-type stepped mating structure is used to maintain the overlapping seal of the axial projection when the independent roller rings undergo radial displacement.

[0010] Preferably, the multi-stage cam structure has several tapered driving surfaces distributed along the central drive rod axially with different tapered angle settings. The tapered angle of the tapered driving surface in the middle of the central drive rod is greater than the tapered angle of the tapered driving surfaces at both ends of the central drive rod. The segmented roller surface assembly forms a drum-shaped profile that is high in the middle and low at both ends by moving the central drive rod.

[0011] Preferably, an external anti-rotation component is provided between the hollow spindle and the segmented roller surface assembly to prevent the outer layer from slipping. The external anti-rotation component includes a limiting key strip disposed on the outer surface of the hollow spindle. A guide keyway is provided on the inner wall of the segmented roller surface assembly, and the guide keyway slides in cooperation with the limiting key strip.

[0012] Preferably, the driving mechanism includes a rotating rod rotatably mounted on a mounting bracket, a traction turntable fixedly mounted at the top of the rotating rod, four traction rods circumferentially mounted on the end face of the traction turntable, and the traction rods fixedly connected to the hollow main shaft, a hydraulic cylinder fixedly mounted at the middle position of the traction turntable, a transmission shaft fixedly mounted at the output end of the hydraulic cylinder, a transmission block fixedly mounted on the transmission shaft, and the transmission block fixedly connected to the central drive rod to achieve axial movement while rotating.

[0013] Preferably, an internal anti-rotation component for achieving synchronous rotation is provided between the hollow spindle and the central drive rod. Both ends of the central drive rod are provided with circumferentially circumferentially limiting slide bars. Both ends of the hollow spindle are provided with cover plates that are slidably connected to the body of the central drive rod. The cover plates are provided with limiting slide holes that are slidably connected to the limiting slide bars.

[0014] Preferably, a self-lubricating guide bushing is provided in the radial guide hole, and the ejector is inserted into the self-lubricating guide bushing. The self-lubricating guide bushing is used to reduce transmission friction and improve the response accuracy of radial displacement.

[0015] Compared with the prior art, the present invention has the following advantages: 1. This invention eliminates the problems of air sluggishness and elastic deformation inherent in traditional air-expansion regulating rollers through a rigid mechanical transmission of multi-stage cams and ejector components. Under high-speed operation, the radial dimension of the roller surface remains firmly locked, preventing compression deformation due to paper tension fluctuations, thereby effectively improving the registration accuracy of label printing.

[0016] 2. This invention solves the industry pain points of easy paper jamming and dust accumulation in segmented rollers by using a labyrinthine step structure, effectively extending the equipment maintenance cycle. At the same time, through the internal and external double anti-rotation design and follow-up hydraulic drive mechanism, it effectively ensures the smoothness of adjustment action under high-speed rotation, avoiding wear and heat caused by relative sliding.

[0017] 3. This invention utilizes a segmented roller surface assembly. When the roller surface is worn due to friction from paper edges or scratches from foreign objects, there is no need to replace the entire main shaft or re-coat the entire assembly. Only the end cover needs to be removed and the damaged independent roller ring replaced separately. This effectively reduces the spare parts cost of the equipment and shortens maintenance downtime, which helps to improve production efficiency. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the pre-printing pretreatment device for paper product labels proposed in this invention; Figure 2 This is a schematic cross-sectional view of the pre-printing pretreatment device for paper product labels proposed in this invention. Figure 3 This is a schematic diagram of the hollow main shaft structure of a pre-printing pretreatment device for paper product labels proposed in this invention; Figure 4 This is a schematic diagram of the ejector structure of a pre-printing pretreatment device for paper product labels proposed in this invention; Figure 5 This is a schematic diagram of the installation of the central drive rod and multi-stage cam structure of a pre-printing pretreatment device for paper product labels proposed in this invention; Figure 6 This is a schematic cross-sectional view of an independent roller ring of a pre-printing pretreatment device for paper product labels proposed in this invention. Figure 7 This is a schematic diagram of the drive mechanism of a pre-printing pretreatment device for paper product labels proposed in this invention.

[0019] In the diagram: 1. Mounting bracket; 2. Hollow spindle; 21. Radial guide hole; 22. Limiting key; 23. Cover plate; 3. Segmented roller surface assembly; 31. Independent roller ring; 32. Labyrinth-type stepped mating structure; 33. Guide keyway; 4. Radial expansion adjustment mechanism; 41. Central drive rod; 42. Multi-stage cam structure; 43. Conical drive surface; 44. Ejector; 45. Driven inclined surface; 46. Elastic reset component; 47. Limiting slide bar; 48. Limiting slide hole; 49. Slide rod; 410. Arc-shaped contact block; 5. Drive mechanism; 51. Rotating rod; 52. Traction turntable; 53. Hydraulic cylinder; 54. Transmission block; 55. Transmission shaft; 56. Traction rod. Detailed Implementation

[0020] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0021] Reference Figures 1-7 A pre-processing device for paper product labels includes a hollow main shaft 2, a segmented roller assembly 3, a radial expansion adjustment mechanism 4, a drive mechanism 5, and a high-rigidity mounting bracket 1. The mounting bracket 1 is preferably a U-shaped frame structure made of HT250 gray cast iron or welded from Q235 thick steel plate, and undergoes vibration aging treatment to eliminate internal stress and ensure shock resistance stability in high-speed printing environments. A guide sliding hole is provided on the left side of the mounting bracket 1.

[0022] like Figure 1 , Figure 2 As shown, the hollow spindle 2 is made of 40Cr alloy structural steel, and its surface has been heat-treated to control the hardness at HB240-280. One end of the hollow spindle 2 is rotatably mounted in the bearing housing on the left side of the mounting bracket 1 via a self-aligning roller bearing. The self-aligning roller bearing can automatically compensate for slight coaxiality deviations caused by installation errors or bending of the long shaft under stress, preventing jamming. One end of the hollow spindle 2 is driven by an external servo motor to rotate the entire roller body at a linear speed (0-350m / min) synchronized with the printing production line.

[0023] In some implementations, such as Figure 3 , Figure 4 , Figure 5 As shown, the hollow spindle 2 has several rows of radial guide holes 21 evenly arranged along the axial direction on its tube wall (for example, 12 groups distributed axially and 4 rows evenly distributed circumferentially). Each radial guide hole 21 is press-fitted with a self-lubricating guide bushing to reduce motion friction and extend service life. This bushing preferably uses a JDB-650 high-strength brass matrix with graphite pillars embedded in a solid lubricated bearing, which can achieve smooth sliding under long-term oil-free or low-oil conditions.

[0024] The radial expansion adjustment mechanism 4 includes a central drive rod 41 coaxially slidably disposed within the cavity of the hollow main shaft 2. The drive rod 41 is made of 20CrMnTi material and undergoes carburizing and quenching treatment to achieve a hardness of HRC58-62. A multi-stage cam structure 42 is machined onto the central drive rod 41. The multi-stage cam structure 42 consists of a series of axially arranged frustums, with the side of each frustum serving as a conical drive surface 43.

[0025] The ejector 44 is inserted into the self-lubricating guide bushing. The ejector 44 consists of a slide rod 49 and an arc-shaped abutment block 410 at the top. The bottom end of the slide rod 49 is machined with a driven inclined surface 45 that matches the slope of the conical drive surface 43. The outer arc surface of the arc-shaped abutment block 410 fits against the inner wall of the segmented roller surface assembly 3. An elastic reset member 46 is provided between the ejector 44 and the hollow main shaft 2. The elastic reset member 46 is a high-strength cylindrical helical compression spring sleeved on the slide rod 49. One end of the spring abuts against the lower bottom surface of the arc-shaped abutment block 410, and the other end abuts against the countersunk hole in the outer wall of the hollow main shaft 2. When the central drive rod 41 moves in the opposite direction to remove the thrust, the elastic reset member 46 uses the restoring force to overcome the centrifugal force and forcibly presses the ejector 44 back, causing the roller surface to retract.

[0026] In some implementations, such as Figure 4 , Figure 6 As shown, the segmented roller assembly 3 is composed of several (e.g., 15) independent roller rings 31 stacked axially. The base material of the independent roller rings 31 is 7075 aerospace aluminum alloy to reduce rotational inertia. Its outer surface is covered with an elastomer layer with a thickness of 5-8 mm. The elastomer layer material is preferably polyurethane rubber with a Shore hardness of A70-75 degrees, and the surface is finely ground to provide stable paper traction friction and avoid scratching the paper surface.

[0027] The mating end faces of two adjacent independent roller rings 31 are a labyrinth-type stepped mating structure 32, and the labyrinth-type stepped mating structure 32 is composed of a positive side structure and a negative side structure: Yang surface structure: The rear end face of the previous independent roller ring 31 is provided with an annular boss, the height of which is set to 5mm and the radial width to 3mm.

[0028] Yin side structure: The front end face of the next independent roller ring 31 is provided with an annular groove, the depth of which is set to 6mm and the radial width to 3.5mm.

[0029] The fit between the positive and negative side structures: In the initial assembly state and under the maximum radial expansion state, the annular boss is always located within the annular groove. Even if the two independent roller rings 31 have a radial height difference of 1-2mm due to differential expansion, the annular boss and the annular groove always overlap in the axial projection (overlap length of at least 3mm), forming a U-shaped tortuous gap. Under the action of the centrifugal force field generated by high-speed rotation, external dust is difficult to enter the gap in the reverse direction, and the paper edge is difficult to bend at a 90° right angle into the gap due to physical rigidity, thus helping to solve the paper clamping problem of traditional segmented rollers.

[0030] The multi-stage cam structure 42 adopts a differential cone angle design, which is used to compensate for the "tight edge" (the paper is loose in the middle and tight at both ends). Let the conical driving surfaces 43 on the central drive rod 41 be numbered N0, N1, N2...Nn from the center to both ends. If the cone angle of the conical driving surface 43 (N0) in the middle is designed to be 15°, then the cone angle gradually decreases from the middle to both ends. For example, N1 is 13°, N2 is 11°, and the cone angle of the conical driving surface 43 (Nn) at the two ends is designed to be 8°.

[0031] According to the triangular wedge transmission principle: radial displacement H = L * cone angle (where L is the axial displacement of the central drive rod 41).

[0032] When the drive mechanism 5 pushes the central drive rod 41 to move axially by 10mm: The radial lifting height of the central independent roller ring 31 is approximately 2.68 mm, and the radial lifting height of the end independent roller ring 31 is approximately 1.40 mm. As a result, the roller surface as a whole forms a smooth drum-shaped profile that is high in the middle and low at both ends, effectively tightening the loose area in the middle of the paper and eliminating wrinkles.

[0033] In some implementations, such as Figure 7 As shown, the drive mechanism 5 includes a hydraulic rotary joint fixed to the outside of the mounting bracket 1. High-pressure oil from the external hydraulic station enters through the stationary end of the rotary joint, and is delivered to the hydraulic cylinder 53, which rotates synchronously with the main shaft, via the internal oil passage of the hollow rotating rod 51. The hydraulic cylinder 53 is fixedly mounted at the center of the traction turntable 52, which is rigidly connected to the end face of the hollow main shaft 2 via four traction rods 56 made of high-strength alloy steel. Therefore, the hydraulic cylinder 53, drive shaft 55, drive block 54, and central drive rod 41 all rotate synchronously with the hollow main shaft 2. When the hydraulic cylinder 53 pushes the central drive rod 41, there is no relative rotation between them, avoiding the problem of overheating and wear of the thrust bearing.

[0034] A double anti-rotation component is provided between the segmented roller assembly 3, the hollow main shaft 2 and the central drive rod 41, and the double anti-rotation component is used to ensure that the segmented roller assembly 3, the hollow main shaft 2 and the central drive rod 41 rotate synchronously.

[0035] Outer anti-rotation layer: A through-type limiting key 22 (preferably made of 45# steel) is fixed to the outer cylindrical surface of the hollow main shaft 2 by screws or integrally milled. A guide keyway 33 is provided on the inner wall of the independent roller ring 31. The depth of the guide keyway 33 (e.g., 8mm) is designed to be greater than the sum of the height of the limiting key 22 (4mm) and the maximum radial expansion amount (3mm), ensuring that the independent roller ring 31 is still held by the limiting key 22 when it expands and floats, and rotates with the hollow main shaft 2 without slipping.

[0036] Inner anti-rotation layer: Rectangular limiting slide bars 47 are provided on the circumference of both ends of the central drive rod 41. Corresponding limiting slide holes 48 are provided on the sealing cover plates 23 at both ends of the hollow spindle 2. This fit restricts the rotational freedom of the central drive rod 41 relative to the hollow spindle 2, retaining only the axial movement freedom, and the left end of the central drive rod 41 is slidably connected to the guide slide hole on the mounting bracket 1.

[0037] Both the hydraulic cylinder 53 and the servo motor are controlled by a servo controller.

[0038] It should be noted that the specific model and specifications of the hydraulic cylinder 53 and the servo motor need to be selected and determined according to the actual specifications of the device. The specific selection and calculation method adopts the existing technology in this field, so it will not be elaborated here.

[0039] The functional principle of this invention can be explained through the following operational methods: When paper products need to be processed: First, the servo motor starts, driving the rotating rod 51 to rotate at high speed, and the hollow main shaft 2 rotates synchronously thereafter. At this time, the hollow main shaft 2 uses the limiting key strip 22 on its surface to drive the outer segmented roller assembly 3 to rotate together, thereby pulling the paper to be fed. At the same time, the central drive rod 41 follows the hollow main shaft 2 to maintain synchronous rotation due to the limitation of the limiting slide strip 47, and there is no relative rotation between the components.

[0040] Subsequently, when paper tension compensation is required, hydraulic oil enters the hydraulic cylinder 53 via the rotary joint. The hydraulic cylinder 53 actuates, pushing the drive shaft 55 and the central drive rod 41 to move axially linearly inside the hollow main shaft 2. Accompanying the movement of the central drive rod 41, the multi-stage cam structure 42 on it is displaced accordingly, and the conical drive surface 43 presses against the driven inclined surface 45 at the bottom of the ejector 44.

[0041] During radial expansion: Under the action of the wedge fit, the axial thrust is converted into a radial lifting force, forcing the ejector 44 to push outward along the radial guide hole 21, supporting each independent roller ring 31. The segmented roller surface assembly 3 quickly forms a drum-shaped profile that is high in the middle and low at both ends, thereby effectively tightening the slack middle part of the paper. During this process, the labyrinthine stepped fit structure 32 between adjacent independent roller rings 31 always maintains overlapping and interlocking to prevent dust intrusion.

[0042] Finally, when the adjustment is complete, the hydraulic cylinder 53 reverses or releases pressure, and the central drive rod 41 retracts. At this time, the elastic reset member 46 releases its elastic force, pressing the ejector member 44 back, and each independent roller ring 31 falls back, restoring the roller surface to its initial flat state.

[0043] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A pre-processing device for paper product labels, comprising a mounting bracket (1), a hollow main shaft (2), and a segmented roller assembly (3), characterized in that, The hollow spindle (2) is provided with a radial expansion adjustment mechanism (4) for locally radially lifting the segmented roller assembly (3) to compensate for the tension of the roller surface. The radial expansion adjustment mechanism (4) includes a central drive rod (41) for providing axial actuation force. The mounting bracket (1) is also provided with a drive mechanism (5) for driving the central drive rod (41) to perform axial reciprocating motion in a rotating state.

2. The paper product label pre-processing device according to claim 1, characterized in that, The segmented roller assembly (3) is coaxially sleeved outside the hollow main shaft (2). The central drive rod (41) is coaxially and movably installed inside the hollow main shaft (2). The segmented roller assembly (3) is driven to produce radial deformation by the axial displacement of the central drive rod (41). One end of the hollow main shaft (2) is rotatably installed on the mounting bracket (1). The mounting bracket (1) has a U-shaped structure. Several radial guide holes (21) are opened on the side wall of the hollow main shaft (2).

3. The paper product label pre-processing device according to claim 2, characterized in that, The radial expansion adjustment mechanism (4) includes a multi-stage cam structure (42) fixed on the central drive rod (41). An ejector (44) is slidably installed in the radial guide hole (21). The multi-stage cam structure (42) is provided with several conical drive surfaces (43). The bottom end of the ejector (44) is provided with a driven inclined surface (45) that abuts against the conical drive surface (43). The driven inclined surface (45) is used to convert the axial force of the central drive rod (41) into a radial lifting force.

4. The paper product label pre-processing device according to claim 3, characterized in that, An elastic reset member (46) is fixedly provided between the ejector (44) and the hollow spindle (2). The elastic reset member (46) is configured to apply a biasing force to the ejector (44) pointing towards the axis and ensure that the ejector (44) and the tapered drive surface (43) always maintain transmission contact. The ejector (44) consists of a slide rod (49) slidably connected to the radial guide hole (21) and an arc-shaped contact block (410) fixed at the top of the slide rod (49) for contacting the segmented roller surface assembly (3). The driven inclined surface (45) is machined at the bottom end of the slide rod (49).

5. The pre-printing pretreatment device for paper product labels according to claim 4, characterized in that, The segmented roller assembly (3) is formed by axially stacking several independent roller rings (31). The mating end faces of two adjacent independent roller rings (31) are provided with a labyrinth-type stepped mating structure (32). The labyrinth-type stepped mating structure (32) is used to maintain the overlapping seal of the axial projection when the independent roller rings (31) undergo radial displacement.

6. The pre-printing pretreatment device for paper product labels according to claim 5, characterized in that, The multi-stage cam structure (42) has several conical driving surfaces (43) distributed along the central drive rod (41) with different cone angle settings. The cone angle of the conical driving surface (43) in the middle of the central drive rod (41) is greater than the cone angle of the conical driving surfaces (43) at both ends of the central drive rod (41). The segmented roller assembly (3) forms a drum-shaped profile that is high in the middle and low at both ends by moving through the central drive rod (41).

7. The pre-printing pretreatment device for paper product labels according to claim 6, characterized in that, An external anti-rotation component is provided between the hollow spindle (2) and the segmented roller surface assembly (3) to prevent the outer layer from slipping. The external anti-rotation component includes a limiting key strip (22) set on the outer surface of the hollow spindle (2). A guide keyway (33) is opened on the inner wall of the segmented roller surface assembly (3), and the guide keyway (33) slides with the limiting key strip (22).

8. The pre-printing pretreatment device for paper product labels according to claim 1, characterized in that, The drive mechanism (5) includes a rotating rod (51) rotatably mounted on the mounting bracket (1). A traction turntable (52) is fixedly mounted on the top of the rotating rod (51). Four traction rods (56) are circumferentially mounted on the end face of the traction turntable (52), and the traction rods (56) are fixedly connected to the hollow main shaft (2). A hydraulic cylinder (53) is fixedly mounted in the middle of the traction turntable (52). A transmission shaft (55) is fixedly mounted on the output end of the hydraulic cylinder (53). A transmission block (54) is fixedly mounted on the transmission shaft (55). The transmission block (54) is fixedly connected to the central drive rod (41) to achieve axial movement while rotating.

9. A pre-processing device for paper product labels according to claim 2, characterized in that, An internal anti-rotation component is provided between the hollow spindle (2) and the central drive rod (41) to achieve synchronous rotation. Both ends of the central drive rod (41) are provided with circumferential limit slides (47). Both ends of the hollow spindle (2) are provided with cover plates (23) that are slidably connected to the rod body of the central drive rod (41). The cover plates (23) are provided with limit slide holes (48) that are slidably connected to the limit slides (47).

10. A pre-processing device for paper product labels according to claim 3, characterized in that, The radial guide hole (21) is provided with a self-lubricating guide bushing, and the ejector (44) passes through the self-lubricating guide bushing. The self-lubricating guide bushing is used to reduce transmission friction and improve the response accuracy of radial displacement.

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