Negative pressure paper feeding mechanism and inkjet graphic output equipment

Abstract

The present invention provides a negative pressure paper feeding mechanism and an inkjet graphic output device. The negative pressure paper feeding mechanism is arranged below an inkjet assembly, which includes an inkjet head. The negative pressure paper feeding mechanism includes a fixed frame, a negative pressure adsorption assembly, and a paper feeding transmission assembly. The negative pressure adsorption assembly is installed in the fixed frame. The negative pressure adsorption assembly includes a bottom shell, an adsorption panel, and a negative pressure fan. A negative pressure chamber is formed on the bottom shell. The adsorption panel is sealed and fixed to the bottom shell and covers the negative pressure chamber. The adsorption panel is provided with multiple lower holes and multiple upper holes connected to the negative pressure chamber. Each lower hole corresponds to each upper hole to form a stepped hole. Each upper hole extends along the paper feeding direction to form an elongated hole. The cross-sectional area of ​​the elongated hole is larger than the cross-sectional area of ​​the lower hole. Multiple negative pressure fans are installed on the lower surface of the bottom shell. The air suction ports of the negative pressure fans are connected to the negative pressure chamber. The present invention effectively solves the industry problems of nozzle clogging and unstable paper feeding in inkjet printing equipment.

Description

Technical Field

[0001] The present invention relates to the technical field of printing equipment, and in particular to a negative pressure paper feeding mechanism and an inkjet graphic output device equipped with the negative pressure paper feeding mechanism. Background Art

[0002] Existing copier paper feed mechanisms typically use friction or suction methods, which can lead to unstable paper feed, easy deviation, and nozzle clogging and other problems. The copier's negative pressure paper feed mechanism is a core component of the printer, used to feed paper during printing. The print nozzle is located directly above the negative pressure paper feed assembly, and printing is completed when the paper passes through the nozzle. Traditional negative pressure paper feed mechanisms continuously exhaust air when there is no paper, causing the nozzle printing surface to dry out and affecting print quality. Therefore, a new paper feed mechanism that combines stable paper feeding with anti-clogging functions is urgently needed. Summary of the Invention

[0003] In view of the above, the present invention provides a negative pressure paper feeding mechanism and an inkjet graphic output device to solve the problems of unstable paper feeding and easy nozzle clogging in the prior art.

[0004] The technical solution of the present invention:

[0005] The present invention provides a negative pressure paper feeding mechanism, which is arranged below an inkjet assembly, wherein the inkjet assembly includes an inkjet head, and the negative pressure paper feeding mechanism includes a fixed frame, a negative pressure adsorption assembly and a paper feeding transmission assembly, wherein the negative pressure adsorption assembly is installed in the fixed frame; the negative pressure adsorption assembly includes a bottom shell, an adsorption panel and a negative pressure fan, a negative pressure cavity is formed on the bottom shell, the adsorption panel is sealed and fixed on the bottom shell and covers the negative pressure cavity, and a plurality of lower holes and a plurality of upper holes connected to the negative pressure cavity are opened on the adsorption panel, each of the lower holes corresponds to each of the upper holes to form a stepped hole, and each of the upper holes extends along the paper feeding direction to form a stepped hole. The elongated holes are formed, and the cross-sectional area of ​​the elongated holes is larger than the cross-sectional area of ​​the lower holes, so that the two rows of lower holes below the inkjet head are away from the inkjet head along the paper feeding direction. The multiple negative pressure fans are installed on the lower surface of the bottom shell, and the air suction port of the negative pressure fan is communicated with the negative pressure chamber; the paper feeding transmission assembly includes a power shaft, a driven shaft and an adsorption belt, and the power shaft and the driven shaft are rotatably installed on both ends of the fixed frame respectively, and the adsorption belt is wound around the power shaft and the driven shaft, and the adsorption belt is tightly attached to the upper surface of the adsorption panel, and a plurality of densely distributed adsorption holes are opened on the adsorption belt, and each of the adsorption holes is communicated with the upper hole at the corresponding position.

[0006] According to one embodiment of the present invention, the adsorption panel includes a lower plate and an upper plate, the lower hole is opened on the lower plate, the upper hole is opened on the upper plate, and the lower plate and the upper plate are tightly stacked and fixed to form a double-layer plate structure.

[0007] According to one embodiment of the present invention, the air outlet of the negative pressure fan located in the middle of the bottom shell faces the exhaust holes on both sides of the fixed frame, and the air outlet of the negative pressure fan located at both ends of the bottom shell faces the middle of the bottom shell.

[0008] According to one embodiment of the present invention, the paper feeding transmission assembly further includes a driving motor and a transmission gear box, and the driving motor drives the power shaft to rotate through the transmission gear box.

[0009] According to one embodiment of the present invention, buckles are installed at the four corners of the adsorption panel, and the buckles press the adsorption belt onto the upper surface of the adsorption panel. The adsorption belt can slide between the adsorption panel and the buckles.

[0010] According to one embodiment of the present invention, it also includes a positioning component installed at two diagonal positions of the adsorption panel, the positioning component includes a positioning block, a pin and a spring, and positioning holes are provided at the positioning block and the other diagonal position of the adsorption panel. The pin is installed in the slide groove of the positioning block and is located at the positioning hole. The spring is installed in the groove of the positioning block and supports the pin so that the pin is pressed against the positioning pin at the bottom of the inkjet assembly inserted into the positioning hole.

[0011] According to one embodiment of the present invention, it also includes a positioning and locking mechanism, which includes a push rod, a sliding shaft, a shift fork, a rack, a reduction gear set and a locking motor; the push rod is installed on both sides of the fixed frame through the sliding shaft for horizontal sliding, and the shift fork is installed at both ends of the push rod, and the shift fork can lock or disengage the positioning pin in the positioning hole; the reduction gear set and the locking motor are installed on the fixed frame, the output gear of the reduction gear set is engaged with the rack, and the input gear of the reduction gear set is engaged with the driving gear of the locking motor, and the locking motor drives the reduction gear set to rotate to drive the push rod to slide horizontally.

[0012] According to one embodiment of the present invention, the positioning and locking mechanism also includes a synchronization shaft and a synchronization gear. The synchronization shaft is rotatably mounted on the fixed frame. One end of the synchronization shaft is connected to the output gear of the reduction gear set, and the other end is connected to the synchronization gear. The synchronization gear is engaged with the rack of the push rod at the corresponding position to achieve synchronous sliding of the push rods on both sides.

[0013] According to one embodiment of the present invention, it also includes a tensioning mechanism, which includes a tensioning shaft, a support and a tension spring. The two supports are respectively hinged on both sides of the fixed frame, and both ends of the tensioning shaft are rotatably mounted on one end of the support. The other end of the support is connected to the fixed frame through the tension spring. The tensioning shaft is located below the power shaft and the driven shaft, and the adsorption belt is wrapped around the outer periphery of the tensioning shaft, the power shaft and the driven shaft arranged in a triangular shape.

[0014] The present invention also provides an inkjet graphic output device provided with the negative pressure paper feeding mechanism of the above embodiment.

[0015] The negative pressure paper feeding mechanism provided by the present invention achieves dual optimization of paper feeding stability and nozzle protection during inkjet printing through a unique structural design. The specific beneficial effects are as follows:

[0016] 1. Intelligent air volume adjustment protects the inkjet head

[0017] When the suction belt is empty, the stepped hole structure of the suction panel plays a key role: although the upper holes are elongated, because there is no paper covering them, the airflow is primarily concentrated at the corresponding suction holes in the lower holes. Because the margin D between the two rows of lower holes along the paper feed direction is much larger than the inkjet head width, and the cross-sectional area of ​​the lower holes is smaller than that of the upper holes, the airflow passing through the inkjet head's print surface is significantly reduced. This design effectively reduces airflow velocity on the printhead surface, inhibiting the evaporation rate of the ink solvent. This fundamentally prevents drying and clogging of the inkjet head due to excessive air convection, significantly improving the printhead's service life and equipment reliability.

[0018] 2. Dynamic adsorption enhances paper feeding stability

[0019] As the suction belt conveys paper, the elongated upper holes connect with the multiple suction holes on the belt, forming a large suction area. The structural characteristic of the upper holes extending along the paper feed direction allows a single elongated hole to cover multiple suction holes, increasing the suction area. This design ensures a uniform and strong negative pressure beneath the inkjet head, ensuring stable conveyance even for paper of varying weights and flatness, avoiding print deviations caused by paper shifting and wrinkling, and significantly improving print accuracy and product quality.

[0020] 3. Stepped hole structure optimizes airflow distribution

[0021] The stepped hole design, formed by the lower and upper holes, creates an airflow buffer zone through the difference in cross-sectional area (upper hole cross-sectional area > lower hole cross-sectional area). When paper is not present, airflow naturally converges within the negative pressure chamber toward the lower holes, where resistance is lower, reducing airflow disturbances in the printhead area. When paper is present, the paper covers the adsorption holes, creating a sealed environment and forcing airflow to diffuse through the upper holes to a wider area, achieving the adaptive function of "energy-saving protection when paper is not present, and efficient adsorption when paper is present." This structure eliminates the need for additional sensors or control systems, achieving dynamic airflow regulation solely through physical aperture design, simplifying device control logic and reducing manufacturing costs.

[0022] 4. Compact structure improves equipment integration

[0023] The negative pressure fan is directly installed on the lower surface of the bottom shell, and the air suction port is connected to the negative pressure chamber to form an integrated negative pressure generating device with a compact structure, which is easier to integrate into compact inkjet equipment. The paper feed transmission assembly adopts a classic transmission structure of a power shaft, a driven shaft and an adsorption belt. The adsorption belt is close to the upper surface of the adsorption panel to ensure that the adsorption holes are precisely aligned with the upper holes. There is no slippage or offset during the transmission process. The overall mechanism operates with low noise, which significantly improves the stability and quietness of the equipment. In summary, the present invention effectively solves the industry problems of nozzle clogging and unstable paper feeding in inkjet printing equipment through innovative points such as stepped hole airflow adjustment, dynamic adsorption area switching, and compact structural design. It reduces equipment maintenance costs while greatly improving printing quality, and has significant technological advancement and market application value.

[0024] The preferred embodiments of the present invention and their beneficial effects will be further described in detail in conjunction with specific implementation methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the following detailed description, they are used to explain the present invention but should not be construed as limiting the present invention. In the accompanying drawings:

[0026] Figure 1 This is a structural diagram from a first perspective of the negative pressure paper feeding mechanism and the inkjet assembly of the present invention;

[0027] Figure 2 A second perspective structural diagram of the negative pressure paper feeding mechanism and the inkjet assembly of the present invention;

[0028] Figure 3 A structural diagram showing the cooperation between the negative pressure paper feeding mechanism and the inkjet assembly according to the present invention from a third perspective;

[0029] Figure 4 This is a first-perspective stereoscopic view of the negative pressure paper feeding mechanism of the present invention after the adsorption belt is removed;

[0030] Figure 5A top view of the adsorption panel of the negative pressure paper feeding mechanism of the present invention;

[0031] Figure 6 for Figure 4 Exploded view of

[0032] Figure 7 This is an exploded view of the adsorption panel of the negative pressure paper feeding mechanism of the present invention;

[0033] Figure 8 This is a second perspective view of the negative pressure paper feeding mechanism of the present invention after the adsorption belt is removed;

[0034] Figure 9 It is a bottom view of the negative pressure adsorption component of the negative pressure paper feeding mechanism of the present invention;

[0035] Figure 10 1. It is a structural diagram of the positioning assembly of the negative pressure paper feeding mechanism of the present invention;

[0036] Figure 11 This is an exploded view of the positioning and locking mechanism of the negative pressure paper feeding mechanism of the present invention.

[0037] Description of the accompanying figures: 1. Fixed frame; 2. Negative pressure adsorption component; 3. Paper feeding transmission component; 10. Inkjet component; 101. Inkjet head; 102. Positioning pin; 20. Negative pressure chamber; 21. Bottom shell; 22. Adsorption panel; 23. Negative pressure fan; 221. Lower hole; 222. Upper hole; 223. Lower plate; 224. Upper plate; 31. Power shaft; 32. Driven shaft; 33. Adsorption belt; 330. Adsorption hole; 34. Drive motor; 35. Transmission gearbox; 36. Press buckle; 4. Positioning assembly; 40. Positioning hole; 41. Positioning block; 42. Pin; 43. Spring; 44. Cover; 5. Positioning locking mechanism; 51. Push rod; 52. Sliding shaft; 53. Shift fork; 54. Rack; 55. Reduction gear set; 56. Locking motor; 57. Synchronous shaft; 58. Synchronous gear; 6. Tensioning mechanism; 61. Tensioning shaft; 62. Support; 63. Tension spring. DETAILED DESCRIPTION

[0038] The following describes the specific embodiments of the present invention in detail with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention and are not intended to limit the present invention.

[0039] See also Figures 1 to 4 The present invention provides a negative pressure paper feeding mechanism disposed below an inkjet assembly 10, which includes an inkjet head 101. The negative pressure paper feeding mechanism includes a fixed frame 1, a negative pressure adsorption assembly 2, and a paper feeding transmission assembly 3. The negative pressure adsorption assembly 2 is mounted within the fixed frame 1.

[0040] See also Figure 5 and Figure 6 The negative pressure adsorption component 2 includes a bottom shell 21, an adsorption panel 22 and a negative pressure fan 23. A negative pressure chamber 20 is formed on the bottom shell 21. The adsorption panel 22 is sealed and fixed on the bottom shell 21 and covers the negative pressure chamber 20. A plurality of lower holes 221 and a plurality of upper holes 222 are provided on the adsorption panel 22, which are connected to the negative pressure chamber 20. Each lower hole 221 corresponds to each upper hole 222 to form a stepped hole. Each upper hole 222 extends along the paper feeding direction to form a long hole, and the cross-sectional area of ​​the long hole is larger than the cross-sectional area of ​​the lower hole 221, so that the two rows of lower holes 221 located below the inkjet head 101 are away from the inkjet head 101 along the paper feeding direction. That is, the two rows of lower holes 221 have a hole margin D along the paper feeding direction that is much larger than the width of the inkjet head 101. A plurality of negative pressure fans 23 are installed on the lower surface of the bottom shell 21 . The air suction ports of the negative pressure fans 23 are in communication with the negative pressure chamber 20 to provide negative pressure for the negative pressure chamber 20 .

[0041] See also Figure 3 and Figure 4 The paper feed transmission assembly 3 includes a power shaft 31, a driven shaft 32, and a suction belt 33. The power shaft 31 and the driven shaft 32 are rotatably mounted on both ends of the fixed frame 1, respectively. The suction belt 33 is wound around the power shaft 31 and the driven shaft 32. The power shaft 31 is driven to rotate, which drives the suction belt 33 and the driven shaft 32 to rotate. The suction belt 33 is in close contact with the upper surface of the suction panel 22. The suction belt 33 is provided with a plurality of suction holes 330, each of which is connected to the upper hole 222 at a corresponding position. The paper is sucked onto the upper surface of the suction belt 33 through the plurality of suction holes 330 for conveyance.

[0042] When there is no paper being transported on the adsorption belt 33, the air volume is concentrated on the adsorption holes 330 on the lower hole 221, which can reduce the air volume passing through the printing surface of the inkjet head 101 and effectively prevent the inkjet head 101 from drying and clogging; when paper is being transported on the adsorption belt 33, the upper hole 222 with a long hole can connect multiple adsorption holes 330, increasing the adsorption area, so that there is sufficient adsorption force under the inkjet head 101 to achieve stable paper feeding.

[0043] The negative pressure paper feeding mechanism provided by the present invention achieves dual optimization of paper feeding stability and nozzle protection during inkjet printing through a unique structural design. The specific beneficial effects are as follows:

[0044] 1. Intelligent air volume adjustment protects the inkjet head

[0045] When no paper is being transported on the suction belt 33, the stepped hole structure of the suction panel 22 plays a key role: although the upper holes 222 are elongated, because they are not covered by paper, the airflow is primarily concentrated at the suction holes 330 corresponding to the lower holes 221. Because the hole margin D between the two rows of lower holes 221 along the paper feed direction is much larger than the width of the inkjet head 101, and the cross-sectional area of ​​the lower holes 221 is smaller than that of the upper holes 222, the airflow passing through the printing surface of the inkjet head 101 is significantly reduced. This design effectively reduces the airflow velocity on the nozzle surface, suppresses the evaporation rate of the ink solvent, and fundamentally prevents the drying and clogging of the inkjet head 101 caused by excessive air convection, significantly improving the nozzle life and equipment reliability.

[0046] 2. Dynamic adsorption enhances paper feeding stability

[0047] When the suction belt 33 conveys paper, the elongated upper holes 222 connect with the multiple suction holes 330 on the suction belt 33, forming a large suction area. The structural characteristic of the upper holes 222 extending along the paper feed direction allows a single elongated hole to cover multiple suction holes 330, increasing the suction area. This design ensures a uniform and strong negative pressure beneath the inkjet head 101, ensuring stable conveyance even for paper of varying weights and flatness, avoiding print deviations caused by paper shifting and wrinkling, and significantly improving print accuracy and product quality.

[0048] 3. Stepped hole structure optimizes airflow distribution

[0049] The stepped design formed by the lower and upper holes 221 and 222 creates an airflow buffer zone through the difference in cross-sectional area (upper hole cross-sectional area > lower hole cross-sectional area). When paper is not present, airflow within the negative pressure chamber 20 naturally converges toward the lower holes 221, where resistance is lower, reducing airflow disturbances in the printhead area. When paper is present, the paper covers the adsorption holes 330, creating a sealed environment and forcing airflow to diffuse through the upper holes 222 over a wider area. This achieves the adaptive function of "energy-saving protection when paper is not present, and efficient adsorption when paper is present." This structure eliminates the need for additional sensors or control systems, achieving dynamic airflow regulation solely through the physical aperture design, simplifying device control logic and reducing manufacturing costs.

[0050] 4. Compact structure improves equipment integration

[0051] The negative pressure fan 23 is mounted directly on the lower surface of the bottom housing 21, with the air intake communicating with the negative pressure chamber 20, forming an integrated negative pressure generating device. This compact structure makes it easier to integrate into compact inkjet equipment. The paper feed drive assembly 3 utilizes a classic transmission structure consisting of a power shaft 31, a driven shaft 32, and a suction belt 33. The suction belt 33 adheres closely to the upper surface of the suction panel 22, ensuring precise alignment between the suction holes 330 and the upper holes 222. This prevents slippage or misalignment during transmission, resulting in a low operating noise level for the entire mechanism, significantly improving the stability and quietness of the device.

[0052] In summary, the present invention effectively solves the industry problems of nozzle clogging and unstable paper feeding in inkjet printing equipment through innovative features such as stepped hole airflow adjustment, dynamic adsorption area switching, and compact structural design. It greatly improves printing quality while reducing equipment maintenance costs, and has significant technological advancement and market application value.

[0053] In this embodiment, please refer to Figure 7 The adsorption panel 22 includes a lower plate 223 and an upper plate 224. The lower plate 223 has a lower hole 221, and the upper plate 224 has an upper hole 222. The lower plate 223 and the upper plate 224 are tightly stacked and fixed to form a double-layer plate structure. For example, bolts or rivets can be used to tightly stack and fix the lower plate 223 and the upper plate 224.

[0054] The double-layer structure formed by tightly stacking the lower plate 223 and the upper plate 224 has the following beneficial effects:

[0055] 1. Modular design reduces manufacturing and maintenance costs

[0056] The adsorption panel 22 adopts a double-layer plate structure with a lower plate 223 and an upper plate 224 tightly stacked, fixed by bolts or rivets to form a modular component. This design splits the complex stepped hole processing into independent single-layer plate processing. The lower plate 223 only needs to open the lower hole 221, and the upper plate 224 processes the long upper hole 222. Both can be quickly processed by punching, which significantly reduces the processing difficulty and precision requirements. During equipment maintenance, if a layer of plate has problems such as wear or blockage, the corresponding single-layer plate can be directly disassembled and replaced without replacing the adsorption panel as a whole. This reduces maintenance costs, shortens downtime for maintenance, and improves equipment utilization efficiency.

[0057] 2. Enhance structural stability and sealing

[0058] After the double-layer panels are tightly fixed with bolts or rivets, a more rigid composite structure is formed with strong deformation resistance. When the negative pressure fan 23 is working, the stable double-layer panel structure can effectively avoid the warping and deformation of the panel due to the negative pressure, ensuring that the adsorption holes 330 and the upper holes 222 always maintain precise alignment, preventing the problem of uneven adsorption force caused by structural deformation. In addition, the contact between the tightly stacked panels can form a good sealing effect, and combined with the adhesion of the adsorption belt 33, it can minimize the leakage of the negative pressure chamber 20, improve the negative pressure utilization efficiency, and reduce energy consumption.

[0059] 3. Flexible adjustment of adsorption performance

[0060] The double-layer plate structure gives the adsorption panel greater customizability. Users can flexibly choose a combination of lower plates 223 and upper plates 224 of different materials and thicknesses according to actual printing needs. For example, a highly wear-resistant upper plate can be used to cope with high-load paper feeding scenarios, or the adsorption force distribution can be optimized by adjusting the length and spacing of the long strip holes in the upper plate. This modular design does not require changing the overall structure. By simply replacing a single layer of plate, the adsorption performance can be dynamically adjusted to meet the paper feeding requirements of different types of paper and different printing speeds, significantly improving the applicability and versatility of the equipment.

[0061] It is understandable that the adsorption panel 22 can be integrally formed, for example, by forming a stepped hole through an engraving machine.

[0062] In this embodiment, please refer to Figure 8 and Figure 9 The air outlets of the negative pressure fan 23 located in the middle of the bottom shell 21 are respectively oriented toward the exhaust holes on both sides of the fixed frame 1. The air outlets of the negative pressure fans 23 located at both ends of the bottom shell 21 are all oriented toward the middle of the bottom shell 21.

[0063] The negative pressure fan 23 of the bottom shell 21 adopts the above arrangement to achieve the following beneficial effects:

[0064] 1. Directional flow guidance to achieve uniform airflow in the negative pressure cavity

[0065] The negative pressure fan 23 located in the center of the bottom shell 21 directs its outlet toward the exhaust holes on both sides of the fixed frame 1, while the negative pressure fans 23 at both ends exhaust air toward the center, creating a symmetrical airflow circulation pattern of "dispersed air in the center and converging air at both ends." This design ensures that the airflow within the negative pressure chamber 20 is distributed with a uniform gradient along the paper feed direction. This layout minimizes pressure fluctuations within the negative pressure chamber, ensuring minimal deviation in the negative pressure value across each upper hole 222 on the suction panel 22. This creates a balanced and stable suction force across the entire width of the paper, effectively preventing paper shifting or wrinkling due to insufficient local suction force.

[0066] 2. Eliminate airflow counteraction and reduce energy loss

[0067] The staggered air outlet design, with the fans at both ends exhausting toward the center and the fans in the center exhausting toward the sides, fundamentally avoids airflow collisions when multiple fans are operating simultaneously. The present invention's differentiated air outlet orientation creates an orderly "convergence-divergence" flow path within the negative pressure chamber 20, improving air volume utilization. Furthermore, directional airflow reduces the load on the fan motors and lowers energy consumption, achieving dual optimization of energy savings and performance.

[0068] 3. Integrated cooling improves system reliability

[0069] The exhaust holes on both sides of the fixed frame 1 are directly connected to the central fan outlet, forming a through-type heat dissipation channel. When the fan is working, the exhausted airflow not only provides power for the negative pressure chamber, but also simultaneously removes heat from the bottom shell 21 and the surrounding components of the fixed frame 1, forming an indirect heat dissipation protection for the heat-generating components. Actual measured data shows that this layout can reduce the temperature of the core area of ​​the device by 5-8°C, effectively slowing the aging of electronic components and ink pipes. It is particularly suitable for high-speed continuous printing scenarios, avoiding abnormal ink viscosity or nozzle failure caused by high temperature, and significantly improving the long-term stability of the equipment.

[0070] 4. Compact layout optimizes space utilization

[0071] The directional fan outlet design is deeply integrated with the fixed frame structure, eliminating the need for additional ducting or heat sinks, reducing the space occupied by the entire negative pressure paper feed mechanism. The central fan exhausts air to both sides, cleverly utilizing the unused space at the edges of the fixed frame. The fans at both ends exhaust air toward the center, providing an efficient airflow solution for the confined space below the inkjet assembly 10. This design is particularly well-suited for compact inkjet devices, enabling miniaturization and lightweighting while maintaining performance.

[0072] In this embodiment, please refer to Figure 4 The paper feeding transmission assembly 3 includes a driving motor 34 and a transmission gear box 35 mounted on the fixed frame 1 . The driving motor 34 drives the power shaft 31 to rotate through the transmission gear box 35 .

[0073] See also Figure 1To ensure that the suction belt 33 is in close contact with the upper surface of the suction panel 22, buckles 36 are installed at the four corners of the suction panel 22. The buckles 36 press the suction belt 33 against the upper surface of the suction panel 22, allowing the suction belt 33 to slide between the suction panel 22 and the buckles 36. The buckles 36 are arranged in a diagonally symmetrical manner, applying balanced pressure at the four corners to ensure the fit between the suction belt 33 and the suction panel 22. This structure can improve the uniformity of the contact pressure between the suction belt 33 and the suction panel 22, effectively avoiding air leakage caused by local poor fit. Combined with the stepped hole design of the suction panel 22, it can improve the utilization rate of negative pressure, enhance the paper adsorption force, and achieve a more stable paper feeding effect.

[0074] See also Figure 5 and Figure 10 The negative pressure paper feeding mechanism of the present invention also includes a positioning assembly 4 installed at two diagonal positions of the adsorption panel 22. The positioning assembly 4 includes a positioning block 41, a pin 42, a spring 43 and a cover plate 44. The positioning block 41 is installed on the adsorption panel 22. Positioning holes 40 are provided at the positioning block 41 and the other diagonal position of the adsorption panel 22 for the positioning pin 102 at the bottom of the inkjet assembly 10 to be inserted for positioning. The pin 42 is installed in the slide groove of the positioning block 41 and is located at the positioning hole 40. The positioning hole 40 cooperates with the pin 42 to form a positioning structure. The spring 43 is installed in the groove of the positioning block 41. One end of the spring 43 is supported on the pin 42, so that the pin 42 is pressed against the positioning pin 102 in the positioning hole 40. The spring 43 provides a pre-tightening force to eliminate the fitting gap. The cover plate 44 is installed on the positioning block 41 to cover the pin 42 and the spring 43. Positioning assembly 4 achieves precise positioning of inkjet assembly 10 and negative pressure paper feed mechanism through its diagonally distributed dual positioning structures and spring 43 preload design. When positioning pin 102 is inserted into positioning hole 40, the preload force of spring 43 pushes pin 42 against the cylindrical surface of positioning pin 102, completely eliminating the gap in the positioning structure, reducing positioning errors and improving printing accuracy.

[0075] See also Figure 8 and Figure 11The negative pressure paper feeding mechanism of the present invention also includes a positioning and locking mechanism 5. The positioning and locking mechanism 5 comprises a push rod 51, a sliding shaft 52, a shift fork 53, a rack 54, a reduction gear set 55, a locking motor 56, a synchronization shaft 57, and a synchronization gear 58. A sliding hole is formed in the push rod 51, and the sliding shaft 52 is inserted into the sliding hole of the push rod 51 and fixed to the fixed frame 1. Push rods 51 are mounted horizontally on both sides of the fixed frame 1 via the sliding shaft 52. A shift fork 53 is mounted at each end of each push rod 51. Driven by the push rod 51, the shift fork 53 can lock or disengage the positioning pin 102 in the positioning hole 40. The rack 54 is mounted horizontally on the push rod 51. The reduction gear set 55 and the locking motor 56 are mounted on the fixed frame 1. The output gear of the reduction gear set 55 meshes with the rack 54, and the input gear of the reduction gear set 55 meshes with the drive gear of the locking motor 56. Synchronizing shaft 57 is rotatably mounted on fixed frame 1. One end of synchronizing shaft 57 is connected to the output gear of reduction gear set 55, and the other end is connected to synchronization gear 58. Synchronizing gear 58 meshes with the corresponding rack 54 of push rod 51. Locking motor 56 drives reduction gear set 55 to rotate. Reduction gear set 55, via the gears at both ends of synchronizing shaft 57, drives rack 54 and push rod 51 to slide horizontally, thereby locking or disengaging shift fork 53 with positioning pin 102 in positioning hole 40.

[0076] The positioning locking mechanism 5 achieves high-precision, synchronized sliding of the push rods 51 on either side of the fixed frame 1 through the coordinated operation of the locking motor 56, reduction gear set 55, synchronization shaft 57, and synchronization gear 58. When the locking motor 56 is activated, the torque amplified by the reduction gear set 55 allows the shift forks 53 on either side to quickly engage the positioning pins 102, providing a stable mechanical foundation for high-precision image and text printing, significantly improving the quality and consistency of the printed product.

[0077] The gears at both ends of the synchronization shaft 57 and the racks 54 on both sides form a mirror transmission structure. Combined with the spring preload of the positioning component 4, a dual positioning system of "elastic pre-positioning + rigid locking" is formed. Within the full temperature range of -10℃ to 60℃, elastic compensation and rigid locking can work together to eliminate the fit clearance caused by thermal expansion, ensuring stable and reliable positioning accuracy.

[0078] See also Figure 4 and Figure 11 The negative pressure paper feeding mechanism of the present invention also includes a tensioning mechanism 6. The tensioning mechanism 6 comprises a tensioning shaft 61, a support 62, and a tension spring 63. The two supports 62 are hinged to either side of the fixed frame 1. The ends of the tensioning shaft 61 are rotatably mounted to one end of each support 62, and the other end of each support 62 is connected to the fixed frame 1 via a tension spring 63. The tensioning shaft 61 is located below the power shaft 31 and the driven shaft 32. The suction belt 33 is wound around the triangularly arranged tensioning shaft 61, the power shaft 31, and the driven shaft 32.

[0079] The tensioning mechanism 6 achieves dynamic, adaptive adjustment of the tension of the suction belt 33 through the cooperation of a tension spring 63 and a hinged support 62. When the suction belt 33 naturally slackens due to prolonged use, the elastic restoring force of the tension spring 63 drives the support 62 to rotate about the hinge point, driving the tensioning shaft 61 downward to press the suction belt 33, automatically compensating for any slack and maintaining a constant belt tension within the optimal operating range. This design effectively prevents slippage and deviation caused by insufficient tension, as well as excessive belt wear caused by excessive tension, ensuring stable and accurate paper conveying.

[0080] The tensioning shaft 61, the power shaft 31 and the driven shaft 32 form a triangle arrangement, which significantly improves the friction between the belt body and the shaft, effectively suppressing the vibration of the adsorption belt caused by inertial impact during high-speed paper feeding, providing a stable paper conveying platform for inkjet printing, and ensuring the clarity and consistency of the printed pattern.

[0081] The present invention also provides an inkjet image and text output device provided with the above-mentioned negative pressure paper feeding mechanism. The inkjet image and text output device can be an inkjet printer, an inkjet copier or an inkjet printer-copier all-in-one machine.

[0082] In the description of the present invention, it should be noted that the terms "upper" and "lower" and the like, indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limitations on the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying importance. The terms "bottom" and "top," as well as "inner" and "outer," refer to directions toward or away from a specific component, respectively.

[0083] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium, or they can refer to connections between the internal parts of two components. A person of ordinary skill in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances. In addition, in the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0084] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A negative pressure paper feeding mechanism, arranged below an inkjet assembly (10), wherein the inkjet assembly (10) includes an inkjet head (101), characterized in that: The negative pressure paper feeding mechanism comprises a fixed frame (1), a negative pressure adsorption component (2) and a paper feeding transmission component (3), wherein the negative pressure adsorption component (2) is installed in the fixed frame (1); The negative pressure adsorption component (2) comprises a bottom shell (21), an adsorption panel (22) and a negative pressure fan (23); a negative pressure cavity (20) is formed on the bottom shell (21); the adsorption panel (22) is sealed and fixed on the bottom shell (21) and covers the negative pressure cavity (20); a plurality of lower holes (221) and a plurality of upper holes (222) are provided on the adsorption panel (22) and are connected to the negative pressure cavity (20); each of the lower holes (221) and each of the upper holes (222) are connected to each of the lower holes (221). The layer holes (222) correspond to each other to form stepped holes, each of the upper layer holes (222) extends along the paper feeding direction to form a long hole, and the cross-sectional area of ​​the long hole is larger than the cross-sectional area of ​​the lower layer holes (221), so that the two rows of lower layer holes (221) located below the inkjet head (101) are away from the inkjet head (101) along the paper feeding direction, and a plurality of negative pressure fans (23) are installed on the lower surface of the bottom shell (21), and the air suction port of the negative pressure fan (23) is communicated with the negative pressure chamber (20); The paper feeding transmission assembly (3) includes a power shaft (31), a driven shaft (32) and an adsorption belt (33), wherein the power shaft (31) and the driven shaft (32) are rotatably mounted on both ends of the fixed frame (1), respectively, and the adsorption belt (33) is wound around the power shaft (31) and the driven shaft (32), and the adsorption belt (33) is in close contact with the upper surface of the adsorption panel (22). A plurality of densely distributed adsorption holes (330) are provided on the adsorption belt (33), and each of the adsorption holes (330) is communicated with the upper hole (222) at a corresponding position; The negative pressure paper feeding mechanism further comprises a positioning assembly (4) installed at two diagonal positions of the adsorption panel (22), the positioning assembly (4) comprising a positioning block (41), a pin (42) and a spring (43), the positioning block (41) and the other diagonal position of the adsorption panel (22) are both provided with a positioning hole (40), the pin (42) is installed in the slide groove of the positioning block (41) and is located at the positioning hole (40), the spring (43) is installed in the groove of the positioning block (41) and abuts the pin (42), so that the pin (42) presses against the positioning pin (102) at the bottom of the inkjet assembly (10) inserted into the positioning hole (40).

2. The negative pressure paper feeding mechanism according to claim 1, characterized in that: The adsorption panel (22) comprises a lower plate (223) and an upper plate (224), the lower hole (221) is opened on the lower plate (223), the upper hole (222) is opened on the upper plate (224), and the lower plate (223) and the upper plate (224) are tightly stacked and fixed to form a double-layer plate structure.

3. The negative pressure paper feeding mechanism according to claim 1, characterized in that: The air outlet of the negative pressure fan (23) located in the middle of the bottom shell (21) faces the exhaust holes on both sides of the fixed frame (1), and the air outlets of the negative pressure fan (23) located at both ends of the bottom shell (21) face the middle of the bottom shell (21).

4. The negative pressure paper feeding mechanism according to claim 1, characterized in that: The paper feeding transmission assembly (3) further comprises a driving motor (34) and a transmission gear box (35), wherein the driving motor (34) drives the power shaft (31) to rotate via the transmission gear box (35).

5. The negative pressure paper feeding mechanism according to claim 1, characterized in that: Press buckles (36) are installed at the four corners of the adsorption panel (22), and the press buckles (36) press the adsorption belt (33) onto the upper surface of the adsorption panel (22). The adsorption belt (33) can slide between the adsorption panel (22) and the press buckles (36).

6. The negative pressure paper feeding mechanism according to claim 1, characterized in that: It also includes a positioning locking mechanism (5), wherein the positioning locking mechanism (5) includes a push rod (51), a sliding shaft (52), a shift fork (53), a rack (54), a reduction gear set (55) and a locking motor (56); The push rod (51) is horizontally slidably mounted on both sides of the fixed frame (1) via the sliding shaft (52), and the shift fork (53) is mounted on both ends of the push rod (51). The shift fork (53) can lock or disengage the positioning pin (102) in the positioning hole (40); The reduction gear set (55) and the locking motor (56) are mounted on the fixed frame (1), the output gear of the reduction gear set (55) is engaged with the rack (54), the input gear of the reduction gear set (55) is engaged with the driving gear of the locking motor (56), and the locking motor (56) drives the reduction gear set (55) to rotate to drive the push rod (51) to slide horizontally.

7. The negative pressure paper feeding mechanism according to claim 6, characterized in that: The positioning locking mechanism (5) further comprises a synchronization shaft (57) and a synchronization gear (58). The synchronization shaft (57) is rotatably mounted on the fixed frame (1). One end of the synchronization shaft (57) is connected to the output gear of the reduction gear set (55), and the other end is connected to the synchronization gear (58). The synchronization gear (58) is engaged with the rack (54) of the push rod (51) at the corresponding position to achieve synchronous sliding of the push rods (51) on both sides.

8. The negative pressure paper feeding mechanism according to claim 1, characterized in that: The invention also includes a tensioning mechanism (6), wherein the tensioning mechanism (6) includes a tensioning shaft (61), a support (62) and a tension spring (63), wherein the two supports (62) are hinged to both sides of the fixed frame (1), respectively, and both ends of the tensioning shaft (61) are rotatably mounted on one end of the support (62), and the other end of the support (62) is connected to the fixed frame (1) through the tension spring (63), and the tensioning shaft (61) is located below the power shaft (31) and the driven shaft (32), and the adsorption belt (33) is wound around the outer periphery of the tensioning shaft (61), the power shaft (31) and the driven shaft (32) arranged in a triangular shape.

9. An inkjet graphic output device, characterized in that: A negative pressure paper feeding mechanism according to any one of claims 1 to 8 is provided.

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