A paper feeding mechanism of a hot stamping die cutting machine

Abstract

The application discloses a paper feeding mechanism of a hot stamping die cutting machine, a plurality of fans in an array are arranged in a power cavity, a through hole is arranged to communicate the power cavity with a suction cavity, a buffer cavity is communicated with the bottom of the power cavity, and an exhaust pipe is communicated with the side wall of the buffer cavity; the opening of the suction cavity is located below the gap between the two ends of a conveying belt, a slide is arranged at the middle position of the inner wall of an outer box body, an inner box body for containing paper is slidably installed on the slide, the linear speed of a paper guide wheel is smaller than that of a conveying wheel, the paper is automatically pulled apart in the front-back direction when the paper is separated from the inner box body, the built-in fan array and the buffer cavity are designed to form uniform laminar negative pressure, and the suction cavity is matched to provide appropriate suction force for paper with different gram weights and prevent the paper from drifting; the relative displacement generated by differential speed conveying automatically pulls apart the front and back paper by a safe distance, and double paper overlapping is physically eliminated; a lateral paper filling structure is matched with a sensor control to realize automatic paper replenishment without shutdown, and paper changing time is shortened to zero.

Description

Technical Field

[0001] This invention relates to the field of post-press processing machinery and equipment, and in particular to a paper feeding mechanism for a hot stamping and die-cutting machine. Background Technology

[0002] Hot stamping and die-cutting machines are core equipment in post-press processing, widely used in the production of tobacco and alcohol packaging, cosmetic boxes, and high-grade gift paper. Their main function is to perform holographic hot stamping or high-precision die-cutting and creasing on the surface of printed materials. As the end market demands higher levels of packaging sophistication, hot stamping and die-cutting machines are developing towards higher speeds, greater intelligence, and faster order changeovers.

[0003] In hot stamping and die-cutting machines, the paper feeding mechanism is the "throat" of the machine, and its stability directly determines the downtime rate and finished product qualification rate of the entire machine. Currently, the mainstream paper feeding mechanism in the industry mainly uses the feeder technology of traditional offset printing machines. However, when dealing with the large format and thick cardboard that hot stamping and die-cutting is unique to, such as gray-backed white cardboard and cardboard, it has revealed many insurmountable defects.

[0004] Existing paper feeding mechanisms typically use external high-pressure vortex fans in conjunction with perforated suction wheels or suction belts for conveying paper. Traditional fans generate mostly turbulent airflow, and the negative pressure value is either not adjustable or its adjustment is delayed. When handling thin paper, excessive negative pressure can cause the paper to collapse and wrinkle, leading to misalignment of the hot stamping pattern. When handling thick paper, due to poor contact between the paper and the belt surface, a large amount of air leakage results in insufficient suction, causing the paper to warp and drift easily during high-speed turns or sudden stops. The suction chamber is usually a single, sealed cavity with poor uniformity of negative pressure distribution, often exhibiting a phenomenon where "the middle is well-held, but the sides are slipping."

[0005] During high-speed paper feeding, paper is prone to sticking together due to cutting tolerances, electrostatic adsorption, or differences in surface energy. Current technology primarily relies on mechanical components such as pressure brushes and release nozzles for paper separation. However, at excessively high speeds, the response speed of mechanical paper separation cannot keep up with the paper separation frequency, and the brushes wear out quickly and adjustments are cumbersome. Guide rollers typically maintain synchronized rotation with the conveyor belt to feed the paper as quickly as possible. While this design offers high speed, it cannot eliminate air layers between the sheets, easily pushing sticky sheets together into the die-cutting section, causing a "stuck" phenomenon.

[0006] Most existing paper feeding platforms are single-lift platform structures. When the paper stack is empty, the equipment must be completely stopped, and the operator needs to move the paper stack, align it, and re-feed the paper. This process usually takes 3-5 minutes, and for large printing plants with dozens of die-cutting machines, the accumulated downtime results in a huge waste of production capacity. In addition, the height of manual paper replenishment is often inconsistent, leading to unstable pressure between the paper feeding rollers and the paper surface, causing first or last sheet feeding failures.

[0007] To address the above issues, some manufacturers have attempted improvements, such as: adding static eliminators: while eliminating static electricity, they are ineffective against the inertial overlap caused by the paper's own weight. Increasing the suction volume: while preventing drift, this exacerbates the risk of thin paper wrinkling and significantly increases energy consumption. Adopting an intermittent paper replenishment mechanism: this is complex in structure, expensive, and still requires slowing down during replenishment, failing to truly achieve "zero downtime." Summary of the Invention

[0008] To overcome the shortcomings of existing technologies, this invention provides a paper feeding mechanism for a hot stamping and die-cutting machine. It adopts a built-in fan array and buffer chamber design to form a uniform laminar negative pressure. Combined with the adsorption chamber, it can provide just the right adsorption force for papers of different weights to prevent drift. By utilizing the relative displacement generated by differential speed transport, the front and rear papers are automatically separated by a safe distance of 15~30mm, which eliminates double-sheet overlap from a physical mechanism. The lateral paper filling structure, combined with sensor control, realizes automatic paper replenishment without stopping the machine, and the paper changing time is shortened to zero.

[0009] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a paper feeding mechanism for a hot stamping and die-cutting machine, comprising a base fixed to the ground by concrete, a conveying structure for conveying cardboard mounted on the base, the conveying structure comprising a base, a conveyor belt mounted on the base via conveyor wheels, and a negative pressure structure for adsorbing and fixing cardboard between the upper and lower belts of the conveyor belt; the negative pressure structure comprises a power chamber and an adsorption chamber located above the power chamber, the power chamber comprising a plurality of fans arranged in an array, a plurality of through holes opening at both ends of the power chamber, the through holes connecting the power chamber and the adsorption chamber, and a buffer chamber connected to the bottom of the power chamber. The side wall is connected to an exhaust pipe; the conveyor belt consists of four belts, with gaps between adjacent belts; the opening of the adsorption chamber is located below the gaps at both ends of the conveyor belt; the buffer chamber passes through the gap in the middle of the conveyor belt and is fixedly installed on the base; a paper feeding structure is installed above the conveying structure, the paper feeding structure includes an outer box, the outer box is fixedly installed on the base by a base frame, a slide is provided in the middle of the inner wall of the outer box, an inner box for holding paper is slidably installed on the slide, and a paper guide wheel is also provided inside the outer box; the linear speed of the paper guide wheel is less than the linear speed of the conveyor wheel, so that the paper is automatically separated in the front-back direction when it leaves the inner box.

[0010] Furthermore, the two ends of the slide are mounted on the outer housing by reinforcing ribs, and a linear drive device is mounted on the reinforcing rib. The output end of the linear drive device is connected to the outer wall of the inner housing and is used to drive the inner housing to move up and down along the slide.

[0011] Furthermore, there are at least two paper guide wheels, which are connected by a belt or transmission chain. Each paper guide wheel is equipped with a drive motor, and its rotation speed is configured to be 60% to 85% of the rotation speed of the transmission wheel, so as to form a speed difference to achieve paper separation.

[0012] Furthermore, the paper output end of the outer box is provided with a baffle, which is configured as an inwardly bent elastic structure to prevent the paper from slipping due to gravity.

[0013] Furthermore, a paper filling structure is provided below the reinforcing rib. The paper filling structure includes a base frame and a guide box. The base frame is fixedly installed on the base. A pusher plate is slidably installed inside the guide box. The pusher plate is installed on the base frame by a hydraulic device. The movement direction of the pusher plate is perpendicular to the lifting direction of the inner box.

[0014] Furthermore, a sensor is installed on the base, located in the middle gap of the conveyor belt. The sensor is used by an external controller to control the timing of the operation of the conveyor wheel, the guide wheel, the linear drive device, and the hydraulic device.

[0015] Furthermore, the fan is an axial flow fan, and the airflow direction is set towards the buffer cavity to form a laminar negative pressure airflow from bottom to top.

[0016] Furthermore, the opening cross-section of the adsorption cavity is elongated and parallel to the conveying direction of the conveyor belt.

[0017] Furthermore, the guide box is provided with an opening for paper filling.

[0018] Furthermore, the sensor is a photoelectric sensor or an ultrasonic sensor. When the sensor detects that there is no paper on the conveyor belt, the controller controls the linear drive device to lift the inner box and controls the hydraulic device to push the pusher plate to replenish the paper to the guide box.

[0019] Compared with the prior art, the beneficial effects that this invention can achieve are: 1. It adopts a built-in fan array and buffer chamber design to form a uniform laminar flow negative pressure. Combined with the adsorption chamber, it can provide just the right adsorption force for paper of different weights and prevent drifting.

[0020] 2. By utilizing the relative displacement generated by differential speed transport, the front and rear sheets are automatically separated by a safe distance of 15~30mm, thus eliminating the overlap of double sheets from a physical mechanism.

[0021] 3. The side-mounted paper filling structure, combined with sensor control, enables automatic paper replenishment without stopping the machine, reducing paper replacement time to zero. Attached Figure Description

[0023] Figure 1This is a three-dimensional structural diagram of the paper feeding mechanism of the hot stamping and die-cutting machine of the present invention; Figure 2 This is a supplementary three-dimensional structural diagram of the paper feeding mechanism of the hot stamping and die-cutting machine of the present invention; Figure 3 This is a schematic diagram of the conveying structure of the paper feeding mechanism of the hot stamping and die-cutting machine of the present invention; Figure 4 This is a three-dimensional structural diagram of the conveying structure of the paper feeding mechanism of the hot stamping and die-cutting machine of the present invention; Figure 5 This is a three-dimensional structural diagram of the negative pressure structure of the paper feeding mechanism of the hot stamping and die-cutting machine of the present invention; Figure 6 This is a supplementary three-dimensional structural diagram of the negative pressure structure of the paper feeding mechanism of the hot stamping and die-cutting machine of the present invention; Figure 7 This is a schematic cross-sectional view of the negative pressure structure of the paper feeding mechanism of the hot stamping and die-cutting machine of the present invention; Figure 8 This is a supplementary cross-sectional schematic diagram of the negative pressure structure of the paper feeding mechanism of the hot stamping and die-cutting machine of the present invention; Figure 9 This is a three-dimensional cross-sectional schematic diagram of the paper feeding structure of the paper feeding mechanism of the hot stamping and die-cutting machine of the present invention; Figure 10 This is a schematic cross-sectional view of the paper feeding structure of the paper feeding mechanism of the hot stamping and die-cutting machine of the present invention; Figure 11 This is a three-dimensional structural diagram of the paper filling structure of the paper feeding mechanism of the hot stamping and die-cutting machine of the present invention.

[0024] The components include: base 1; conveying structure 2; base 21; conveying wheel 22; conveyor belt 23; negative pressure structure 24; power chamber 241; adsorption chamber 242; through hole 243; fan 244; buffer chamber 245; exhaust pipe 246; sensor 25; paper feeding structure 3; outer box 31; base frame 32; reinforcing rib 33; slide rail 34; linear drive device 35; inner box 36; guide wheel 37; baffle 38; paper filling structure 4; base frame 41; pusher plate 43; guide box 44. Detailed Implementation

[0025] To make the technical means, creative features, and achieved objectives and effects of this invention easier to understand, the invention is further described below with reference to specific embodiments. However, the following embodiments are merely preferred embodiments of this invention and not all of them. Other embodiments obtained by those skilled in the art based on the embodiments described herein without creative effort are all within the protection scope of this invention. Unless otherwise specified, the experimental methods in the following embodiments are conventional methods, and the materials and reagents used in the following embodiments are commercially available unless otherwise specified.

[0026] Combination Figure 1 — Figure 11As shown, the present invention provides a paper feeding mechanism for a hot stamping and die-cutting machine, comprising: a rectangular block-shaped base 1, which is fixed to the ground by concrete to support the device; a conveying structure 2 is installed on the base 1, which is mounted above the base 1, and the conveying structure 2 includes a base 21, conveying wheels 22 rotatably mounted on both ends of the base 21 via bearing seats, and a conveyor belt 23 wound around the conveying wheels 22; the conveyor belt 23 is composed of four rectangular strips arranged in parallel at intervals, with strip-shaped gaps between adjacent strips; a negative pressure structure 24 is embedded between the upper and lower strips of the conveyor belt 23, including an adsorption chamber 242, a power chamber 241, and a buffer chamber 245 sealed and connected sequentially from top to bottom; axial flow fans 244 are fixedly installed in a rectangular array inside the power chamber 241, and the number of axial flow fans 244 is set to 3- according to the size of the space inside the power chamber 241. Nine, the power chamber 241 has through holes 243 on both sides of the sidewalls of the two ends to connect to the adsorption chamber 242; the bottom sidewall of the buffer chamber 245 is connected to the exhaust pipe 246; the exhaust pipe 246 can discharge the gas generated by the axial flow fan 244, and an external device can be added to recover and utilize the wind power generated by the exhaust pipe 246. The paper feeding structure 3 is provided above the conveying structure 2. The paper feeding structure 3 includes an outer box 31 and an inner box 36 that is slidably set inside the outer box 31; multiple paper guide wheels 37 are provided in the inner box 36. The multiple paper guide wheels 37 are installed at an angle at the paper output end of the outer box 31. The conveying plane of the paper guide wheel group 37 is at an angle of 5° to 15° with the horizontal plane, and the linear speed of the paper guide wheel group 37 is configured to be 60% to 85% of the linear speed of the conveying wheel 22; a sensor 25 is fixedly installed on the base 21. The sensor 25 is located in the middle gap of the conveyor belt 23 and is used to detect the paper position. A speed difference is created between the inclined, slow-moving guide rollers 37 and the horizontal, fast-moving suction conveyor belt 23, causing the paper to automatically separate when it leaves the paper stack. This, combined with negative pressure suction, prevents warping and achieves non-overlapping paper feeding. Slides 34 are welded to both sides of the inner wall of the outer casing 31, with a C-shaped cross-section. The outer walls of the inner casing 36 are engaged with the slides 34 by sliders. The bottom of the inner casing 36 has a hollow structure, directly facing the suction chamber 242 below. A linear drive device 35 is fixed below the top beam of the outer casing 31 by reinforcing ribs 33. The linear drive device 35 is preferably a hydraulic cylinder, with its piston rod end fixedly connected to the inner casing 36 via a flange. The C-shaped slides ensure torsional rigidity during the lifting and lowering of the inner casing, the hollow bottom allows negative pressure to act directly on the top layer of the paper stack, and the hydraulic drive provides a stable lifting force. The guide roller assembly 37 includes at least two metal rollers coated with polyurethane, and the roller surfaces are provided with anti-slip knurling. The guide roller assembly 37 is driven by an independent servo motor, and its rotational speed is configured to be 70% of the rotational speed of the conveyor roller 22. The polyurethane material increases the coefficient of friction to prevent slippage, and the 70% rotational speed ratio is the optimal critical point for preventing stacking of 300g~800g jammed paper, which can both create distance and prevent tearing of the paper.A baffle 38 is hinged to the paper output edge of the outer casing 31. The baffle 38 is made of spring steel sheet with a thickness of 3mm to 5mm and is bent inward to form an arc-shaped guide surface with a radius of curvature R of 10mm to 20mm. The spring steel sheet has elastic preload, and the arc-shaped guide surface guides the paper to transition smoothly, preventing the thick cardboard from drooping due to gravity and touching the hard edge of the machine, causing paper jams. It also includes a paper filling structure 4, which is located to the side and below the paper feeding structure 3. The paper filling structure 4 includes an L-shaped base frame 41, which provides low center of gravity support and is arranged laterally without occupying the longitudinal space of the main unit. A hydraulic device 42 is fixed to the base frame 41 by anchor bolts. The piston rod end of the hydraulic device 42 is connected to a vertically arranged pusher plate 43, and an upward-opening guide box 44 is provided in front of the pusher plate 43. This enables automatic paper replenishment without stopping the machine. Sensor 25 is a through-beam photoelectric sensor. Through-beam photoelectric sensors have high detection accuracy and are not affected by ambient light. The signal of sensor 25 is connected to a PLC controller, which enables millisecond-level coordination of all machine actions. The controller controls the timing of the actions of the conveyor wheel 22, the paper guide wheel 37, the linear drive device 35, and the hydraulic device 42 through a frequency converter. The blades of fan 244 are made of carbon fiber composite material, and the windward side of the blades is designed with an airfoil profile. The diameter of the through hole 243 gradually decreases from the center of the power cavity 241 to both ends, resulting in a gradient distribution of negative pressure in the adsorption cavity 242, which is high in the middle and low on both sides. The carbon fiber blades reduce weight and noise, and the gradient negative pressure design adapts to paper of different widths, preventing air leakage on both sides of narrow paper from causing insufficient adsorption force. The opening cross-section of the adsorption cavity 242 is a long, narrow slit. The cross-sectional area of ​​the buffer cavity 245 is larger than that of the power cavity 241, and the inner wall of the buffer cavity 245 is lined with sound-absorbing cotton. The working surface of the pusher plate 43 is flush with the inclined guide surface, and the movement direction of the pusher plate 43 is perpendicular to the lifting direction of the inner box 36 in space. When the sensor 25 does not detect a paper signal for 3 consecutive seconds, the controller determines that the paper is empty and then controls the linear drive device 35 to lift the inner box 36 until the paper triggers the sensor. At the same time, the controller controls the hydraulic device 42 to push the pusher plate 43 to the guide box 44 to perform a paper replenishment action.

[0027] The foregoing has shown and described the basic principles, main features, and advantages of the present 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 preferred examples and are not intended to limit 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 claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A paper feeding mechanism for a hot stamping and die-cutting machine, comprising a base (1) fixed to the ground by concrete, wherein a conveying structure (2) for conveying paperboard is mounted on the base (1), characterized in that: The conveying structure (2) includes a base (21), on which a conveyor belt (23) is mounted via a conveyor wheel (22). A negative pressure structure (24) for adsorbing and fixing cardboard is provided between the upper and lower belts of the conveyor belt (23). The negative pressure structure (24) includes a power chamber (241) and an adsorption chamber (242) located above the power chamber. Multiple fans (244) are arranged in an array inside the power chamber (241). Multiple through holes (243) are opened at both ends of the power chamber (241). The through holes (243) connect the power chamber (241) and the adsorption chamber (242). A buffer chamber (245) is connected to the bottom of the power chamber (241). An exhaust pipe (246) is connected to the side wall of the buffer chamber (245). The conveyor belt (23) consists of four belts, with two adjacent belts... A gap is provided between the belts. The opening of the adsorption chamber (242) is located below the gap between the two ends of the conveyor belt (23). The buffer chamber (245) passes through the gap in the middle of the conveyor belt (23) and is fixedly installed on the base (21). A paper feeding structure (3) is installed above the conveying structure (2). The paper feeding structure (3) includes an outer box (31). The outer box (31) is fixedly installed on the base (21) through the base frame (32). A slide rail (34) is provided in the middle of the inner wall of the outer box (31). An inner box (36) for holding paper is slidably installed on the slide rail (34). A paper guide wheel (37) is also provided inside the outer box (31). The linear speed of the paper guide wheel (37) is less than the linear speed of the conveyor wheel (22), so that when the paper leaves the inner box (36), the gap is automatically widened in the front and back direction.

2. The paper feeding mechanism of the hot stamping and die-cutting machine according to claim 1, characterized in that: The two ends of the slide (34) are mounted on the outer box (31) by reinforcing ribs (33). A linear drive device (35) is mounted on the reinforcing ribs (33). The output end of the linear drive device (35) is connected to the outer wall of the inner box (36) to drive the inner box (36) to rise and fall along the slide (34).

3. The paper feeding mechanism of the hot stamping and die-cutting machine according to claim 2, characterized in that: There are at least two paper guide wheels (37), which are connected by belts or transmission chains. Each paper guide wheel (37) is equipped with a drive motor, whose rotation speed is configured to be 60% to 85% of the rotation speed of the transmission wheel (22) to form a speed difference to achieve paper separation.

4. The paper feeding mechanism of the hot stamping and die-cutting machine according to claim 3, characterized in that: The paper output end of the outer box (31) is provided with a baffle (38), which is configured as an inwardly bent elastic structure to prevent the paper from slipping due to gravity.

5. The paper feeding mechanism of the hot stamping and die-cutting machine according to claim 4, characterized in that: A paper filling structure (4) is provided below the reinforcing rib (33). The paper filling structure (4) includes a base frame (41) and a guide box (44). The base frame (41) is fixedly installed on the base (21). A pusher plate (43) is slidably installed inside the guide box (44). The pusher plate (43) is installed on the base frame (41) through a hydraulic device (42). The movement direction of the pusher plate (43) is perpendicular to the lifting direction of the inner box (36).

6. The paper feeding mechanism of the hot stamping and die-cutting machine according to claim 5, characterized in that: A sensor (25) is provided on the base (21). The sensor (25) is located in the middle gap of the conveyor belt (23). The sensor (25) is used by an external controller to control the timing of the operation of the conveyor wheel (22), the paper guide wheel (37), the linear drive device (35) and the hydraulic device (42).

7. The paper feeding mechanism of the hot stamping and die-cutting machine according to claim 1, characterized in that: The fan (244) is an axial flow fan, and the airflow direction is set towards the buffer cavity (245) to form a laminar negative pressure airflow from bottom to top.

8. The paper feeding mechanism of the hot stamping and die-cutting machine according to claim 1, characterized in that: The opening cross-section of the adsorption cavity (242) is elongated and parallel to the conveying direction of the conveyor belt (23).

9. The paper feeding mechanism of the hot stamping and die-cutting machine according to claim 5, characterized in that: The guide box (44) is provided with an opening for paper filling.

10. The paper feeding mechanism of the hot stamping and die-cutting machine according to claim 6, characterized in that: The sensor (25) is a photoelectric sensor or an ultrasonic sensor. When the sensor (25) detects that there is no paper on the conveyor belt (23), the controller controls the linear drive device (35) to lift the inner box (36) and controls the hydraulic device (42) to push the pusher plate (43) to replenish paper to the guide box (44).

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