Printing process of water-based polyurethane printing ink

Abstract

The invention relates to the technical field of circuit printing, in particular to a printing process of water-based polyurethane printing ink, which comprises the following steps of: 1, acquiring a printing area of a circuit substrate, and extracting an image of the area; step 2; a printing path of a circuit substrate plane is constructed according to an extracted image, a printing mode is selected to be suitable for a surface with more contacts, at the moment, a printing base layer forms a latticed state on a circuit board, and metal powder is in a sheet shape, so that a plurality of metal powder points can be distributed at the contacts in an array manner, and the contact area is increased. In this way, heat is absorbed quickly and intensively, the heat can pass through contacts conveniently during printing, and the printing stability is better.

Description

Technical Field

[0001] The invention relates to the technical field of circuit printing, in particular to a printing process using water-based polyurethane printing ink. Background Art

[0002] The printing process of printed circuit boards involves printed circuits with copper-clad substrates as the substrate, which consists of substrates, copper foil and adhesives. The substrate is an insulating layer. It is made of synthetic polymer resin and reinforcing materials; a layer of pure copper foil with high conductivity and good solderability is covered on the surface of the substrate.

[0003] There are convex and concave points on the solder contact angle of the processed substrate. Generally, a protective layer is printed on the circuit board. The existing protective layer is printed. After the circuit board is printed, the heat is not easy to dissipate. Moreover, for circuit boards with more solder points and etched circuit boards, the same method is used, which affects the service life. Summary of the invention

[0004] The object of the present invention is to provide.

[0005] To achieve the above object, the present invention is implemented by the following technical scheme: a printing process using water-based polyurethane printing ink, comprising the following steps:

[0006] Step 1: Obtain the printed area of ​​the circuit substrate and extract the image of the area;

[0007] Step 2: construct a printing path of the circuit substrate plane according to the extracted image and select a printing mode;

[0008] Step three: the printing mode includes a flat printing mode and a convex dot printing mode;

[0009] Wherein, the planar printing mode comprises the following steps:

[0010] S1: forming a base ink film layer on the plane of the circuit substrate;

[0011] S2: During the formation of the base ink film layer, a dispersed metal powder layer is constructed, and a middle ink film layer is constructed;

[0012] S3: forming a surface ink film layer;

[0013] The convex point printing mode comprises the following steps:

[0014] S1: forming a grid-shaped base ink film layer on the plane of the circuit substrate;

[0015] S2: before the grid-like base ink film layer is formed, metal powder is filled in the grid, and a thin sheet metal layer is printed on the surface of the circuit substrate in parallel;

[0016] S3: forming a surface ink film layer;

[0017] Step 4: Drying the printed layer.

[0018] Preferably, step two also includes acquiring the image using the CNN feature extraction method, and judging the situation of image spots based on the state in the extracted image. If there are no spots on the image surface, the plane printing mode of printing mode two is adopted; if there are spots on the image surface, the convex dot printing mode of printing mode one is adopted.

[0019] Preferably, the ink film layer is water-based polyurethane printing ink;

[0020] Preferably, the flat printing mode and the convex dot printing mode also include a printing device, which includes an operating platform, a storage mechanism is arranged on the operating platform, and a printing surface roller, a material dividing mechanism and a printing base roller are arranged in sequence from left to right at the bottom of the storage mechanism.

[0021] Preferably, the storage mechanism includes an ink storage part, a powder storage box arranged in the ink storage part, a powder bin is arranged in the powder storage box, the powder bin is connected to a vacuum tank through a quantitative feeder, the inner cavity of the vacuum tank is connected to a vacuum pump, the feed port of the vacuum tank is connected to a feed pipe through a solenoid valve, the feed pipe is provided with a rubber sleeve, and the rubber sleeve is mounted on the feed mechanism.

[0022] Preferably, a rotating motor is provided on the material dividing mechanism, and the material dividing mechanism includes an arc-shaped isolation sleeve, the arc-shaped isolation sleeve has a lower material dividing port and an upper material dividing port, a material dividing sleeve switched in the arc-shaped isolation sleeve is provided in the arc-shaped isolation sleeve, the rotating motor drives the material dividing sleeve to move between the lower material dividing port and the upper material dividing port, the material dividing sleeve is provided with a lower discharge port and an upper discharge port matching the lower material dividing port and the upper material dividing port, an isolation plate is provided in the material dividing sleeve near the upper discharge port, and when the upper discharge port is connected with the upper material dividing port, the isolation plate separates the sliding cavity into a gathering cavity and a dispersion cavity.

[0023] Preferably, the printing base roller includes a hollow roller, which is sleeved with a grid screen sleeve, the grid screen sleeve includes a material storage part, the material storage part is opened with a plurality of grid openings, the hollow roller is provided with a discharge plate at equal intervals, a grid plate is elastically provided at the position of the discharge plate in the hollow roller, both ends of the grid plate are provided with outgoing ends, the outgoing ends extend into an annular notch provided on the outer side of the hollow roller, the outgoing ends are elastically connected to the inner wall of the annular notch through a silicone pad, a connecting block connecting the guide block is provided on the material distribution sleeve, an offset slide is provided in the annular notch, an offset rod is provided in the offset slide, one end of the offset rod is fixedly connected to the extrusion plate, a tightening hoop is provided on the periphery of the plurality of outgoing ends, and one end of the tightening hoop is close to the connecting block.

[0024] Preferably, a plurality of feed caps are arranged on the inner side of the discharge plate, and the feed caps include a bell tube, a cap sleeve block is arranged at the inner end of the bell tube, a plurality of enlarged holes are arranged at the waist of the bell tube, and the circular holes on the grid plate are sleeved on the bell tube to seal the enlarged holes.

[0025] Preferably, the hollow roller is rotatably connected to a discharge pipe provided on one side of the storage mechanism, the rotary motor is fixedly connected to the discharge pipe, the hollow roller comprises a roller body, and a rubber ring is provided on the outer side of the roller body.

[0026] By adopting the above technical solution, the beneficial effects of the present invention are:

[0027] 1. After the base ink film layer formed on the bottom base layer is coated, the metal powder can be scattered on the surface of the base ink film layer and evenly wrapped by the base ink film layer under the action of gravity.

[0028] 2. During flat printing, a loose powder layer can be formed on the surface of the circuit board without contacting the circuit board, which can effectively dissipate heat. In addition, the layered printing method can dry faster, have better molding effects, and improve the mechanical properties of the circuit board surface.

[0029] 3. The convex dot printing mode is suitable for surfaces with more contacts. At this time, the printed base layer forms a grid-like state on the circuit board, and the metal powder is in flake form. The advantage of this is that multiple metal powder points can be distributed in an array at the contacts, so that the heat can be absorbed quickly and concentratedly, and it is convenient to pass through the contacts during printing, and the printing stability is better. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is the principle diagram of the present invention;

[0031] Figure 2 is a schematic diagram of a printing device of the present invention;

[0032] Figure 3 It is a schematic diagram of the printing base roller in the present invention;

[0033] Figure 4 is a cross-sectional view of the storage mechanism of the present invention;

[0034] Figure 5 is a schematic diagram of a grid plate in the present invention;

[0035] Figure 6 It is a front cross-sectional view of the printing base roller and the material distribution mechanism in the present invention;

[0036] Figure 7 is a cross-sectional view of the printing base roller in the present invention;

[0037] Figure 8 Schematic diagram of the feed cap in the present invention. DETAILED DESCRIPTION

[0038] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0039] In order to better understand the printing process of a water-based polyurethane printing ink provided in the embodiment of the present application, after the existing circuit board is produced, the surface is protected by a surface coating method, the most common of which is OSP coating. The common coating is component oxidation, which protects the safety of the welding point, but its effect is not obvious, and there are many types of circuit boards. Some of them use a single welding contact foot method, which affects the heat dissipation and normal use of the entire circuit board. Therefore, a new way of protecting the circuit board is adopted to comprehensively protect the circuit board. This method is to use water-based polyurethane printing ink in the field of printed circuit boards (PCBs), which is mainly reflected in its environmental protection, good adhesion and excellent mechanical properties. Compared with traditional solvent-based inks, water-based polyurethane inks are more environmentally friendly because they have a lower content of volatile organic compounds (VOCs) and are more friendly to the environment and the health of operators.

[0040] Reference Figure 1 A printing process using a water-based polyurethane printing ink is shown, comprising the following steps:

[0041] Step 1: Obtain the printed area of ​​the circuit substrate and extract the image of the area;

[0042] Step 2: construct a printing path of the circuit substrate plane according to the extracted image and select a printing mode;

[0043] Step three: the printing mode includes a flat printing mode and a convex dot printing mode;

[0044] After acquiring the image using the CNN feature extraction method, the situation of image spots is judged according to the state in the extracted image. If there are no spots on the image surface, the plane printing mode of printing mode 2 is adopted. If there are spots on the image surface, the convex dot printing mode of printing mode 1 is adopted.

[0045] The number of spots is used to distinguish whether there are solder contacts on the surface of the circuit board. When there are solder contacts, the printing mode will be different because there are convex or concave contacts and the board surface. Therefore, when printing, there will be multiple printings and the coating cannot be completely formed. Therefore, the convex printing mode is used. When there are fewer spots, the flat printing mode can be used.

[0046] The difference between the secondary printing process and the traditional printing process is that, when the printed circuit board is used, its coating must not affect its normal use. The heat dissipation limit of the common coating is the heat dissipation limit of the printing ink. Therefore, the coating will affect the normal heat dissipation of the circuit board to a certain extent. Therefore, in the improved printing process, the direct printing method can form a multi-layer printing effect at the same time in one printing. The base printing is to form a more viscous coating on the surface of the circuit board. To a certain extent, the raised and recessed areas can form pre-aggregation, which can eliminate the distance difference. The second layer is the heat dissipation layer, and the third layer is the protective layer. In this way, an overall coating standard can be formed, which is more efficient than the existing one and can solve the problem of multiple multi-layer printing.

[0047] Wherein, the planar printing mode comprises the following steps:

[0048] S1: forming a base ink film layer on the plane of the circuit substrate;

[0049] S2: During the formation of the base ink film layer, a dispersed metal powder layer is constructed, and a middle ink film layer is constructed;

[0050] S3: forming a surface ink film layer;

[0051] The convex point printing mode comprises the following steps:

[0052] S1: forming a grid-shaped base ink film layer on the plane of the circuit substrate;

[0053] S2: before the grid-like base ink film layer is formed, metal powder is filled in the grid, and a thin sheet metal layer is printed on the surface of the circuit substrate in parallel;

[0054] S3: forming a surface ink film layer;

[0055] Step 4: Drying the printed layer.

[0056] Regarding the advantages of the two printing modes, first, after the base ink film layer formed on the bottom base is applied, the metal powder can be scattered on the surface of the base ink film layer and evenly wrapped by the base ink film layer under the action of gravity. Compared with the prior art, the advantage of adding metal powder to the coating is more obvious, because the addition of powder in the prior art relies on the stirring of solution and powder, so the dispersion of the powder is poor, and the metal powder may easily agglomerate in the ink, resulting in uneven effects during printing. In addition, since the density of metal powder is usually high, it may settle in the ink, resulting in ink stratification during the printing process, affecting the printing quality. To avoid this situation, it may be necessary to increase the stirring frequency of the ink or use a special dispersant. More importantly, metal powder may increase the wear of the printing equipment, especially during high-speed printing, metal particles may cause damage to the print head or other key components, and this printing process does not need to consider the above situation at all.

[0057] In addition, the advantages of flat printing and convex printing mode are:

[0058] During flat printing, a loose powder layer can be formed on the surface of the circuit board without contacting the circuit board, which can effectively dissipate heat. In addition, the layered printing method can dry faster, have better molding effects, and improve the mechanical properties of the circuit board surface.

[0059] The convex dot printing mode is suitable for surfaces with more contacts. At this time, the printing base layer forms a grid-like state on the circuit board, and the metal powder is in flake form. The advantage of this is that multiple metal powder points can be distributed in an array at the contacts, so that heat can be absorbed quickly and concentratedly, and it is convenient to pass through the contacts during printing, and the printing stability is better.

[0060] Benefits of adding metal powder: Enhanced mechanical strength: Metal powder can improve the wear and scratch resistance of the coating, increase the service life and durability of the printed product, especially in applications with large mechanical friction. Metal powder has anti-corrosion properties and can be used to make anti-corrosion coatings to protect the substrate from environmental influences. Heat dissipation performance: The high thermal conductivity of metal powder can improve the heat dissipation performance of ink, which is particularly important in the printing of electronic components. By improving the heat dissipation efficiency, the service life of electronic equipment can be extended and its performance can be improved. Metal powder can give the ink electromagnetic shielding capabilities and is used to manufacture electromagnetic compatibility (EMC) components to protect electronic equipment from electromagnetic interference (EM I).

[0061] The ink film layer is water-based polyurethane printing ink.

[0062] Reference Figures 2 to 8As shown, the flat printing mode and the convex dot printing mode also include a printing device, which includes an operating platform 1, on which a storage mechanism 2 is arranged, and a printing surface roller 4, a material dividing mechanism 3 and a printing base roller 5 are arranged in sequence at the bottom of the storage mechanism 2 from left to right.

[0063] A clamp for clamping the circuit board is provided on the operating platform 1, and the top of the circuit board is higher than the top of the clamp. The storage mechanism 2 transfers the ink to the printing surface roller 4 and the printing base roller 5 through a pump. The brush base roller 5 is located in front of the travel direction and is used to form a bottom ink layer on the circuit board. The printing surface roller 4 is used to cover the metal powder distributed by the distribution mechanism 3 to form a surface layer.

[0064] Among them, the printing base roller 5 includes a hollow roller 51, and a mesh screen sleeve 52 is sleeved on the hollow roller 51. The mesh screen sleeve 52 includes a material storage part 522, and the material storage part 522 is used to absorb the ink in the discharge pipe 28. A plurality of mesh openings 521 are opened on the material storage part 522. The function of the mesh openings 521 is to store ink when there is a lot of ink, and to accept metal powder when there is little ink, that is, when convex dots are printed, to form a block state in the inner cavity. Discharge plates 53 are arranged at equal intervals on the hollow roller 51, and a mesh plate 54 is elastically arranged at the position of the discharge plate 53 in the hollow roller 51. Outward ends 541 are arranged at both ends of the mesh plate 54, and the outward ends 541 extend into the annular notch arranged on the outside of the hollow roller 51. The outward ends 541 are elastically connected to the inner wall of the annular notch through the silicone pad 55. A connecting block connecting the guide block 58 is arranged on the material distribution sleeve 32, and a mesh plate 54 is arranged in the annular notch. There is an offset slide, and an offset rod 57 is arranged in the offset slide. One end of the offset rod 57 is fixedly connected to the extrusion plate 56, and a tightening hoop 59 is arranged on the periphery of multiple outward ends 541. One end of the tightening hoop 59 is close to the connecting block. When the rotating motor 6 rotates a certain angle, the guide block 58 will make the extrusion plate 56 move toward the position of the axis center, and then the roller body on one side of the forward direction can quickly penetrate the ink, so that when the printing surface is about to contact the roller body, the metal powder can be printed on the circuit board in block shape. This is used for convex dot printing, and when the tightening hoop 59 rotates the rotating motor 6 in the opposite direction, after the connecting block contacts one end of the tightening hoop 59, when one end of the tightening hoop 59 moves, the entire tightening hoop 59 is rounded, which will make the multiple outward ends 541 move toward the position of the axis center, and then, the multiple grid plates 54 and the inner wall of the hollow roller 51 will present a gap, and then the ink seepage amount at this time will increase, which is used for flat printing.

[0065] When in plane printing mode, the rotating motor 6 makes the connecting block close to the tightening hoop 59, and then the tightening hoop 59 is tightened, and the multiple mesh plates 54 move toward the axis. There is a gap between the multiple mesh plates 54 and the discharge plate 53. At this time, the ink will penetrate the surface of the discharge plate 53, and the mesh screen sleeve 52 can store the ink. In this way, the plane printing is in the plane printing state. It should be noted that the offset rod 57 makes the outer end 541 move farther toward the axis.

[0066] When in the convex dot printing mode, the rotating motor 6 causes the guide block 58 to squeeze the extrusion plate 56, so that the offset rod 57 moves in the offset slide, and then the offset rod 57 causes the front extrusion plate 56 to move toward the axis of the grid plate 54 in the moving direction, so that the ink to be applied on the front side can be attached to the circuit board, and the ink can also be infiltrated in the metal powder collected in the grid opening 521, so that the block-shaped metal powder is attached to the circuit board.

[0067] In the above embodiment, a plurality of feed caps are arranged on the inner side of the discharge plate 53, and the feed caps include a bell tube 531, a cap sleeve block 533 is arranged at the inner end of the bell tube 531, a plurality of enlarged holes 532 are arranged at the waist of the bell tube 531, and the circular holes on the mesh plate 54 are sleeved on the bell tube 531, and the enlarged holes 532 are sealed.

[0068] When controlling ink seepage, when the mesh plate 54 moves toward the axial position, the circular hole on the mesh plate 54 moves at the waist of the bell tube 531. After the mesh plate 54 wrapped around the enlarged hole 532 is displaced, the enlarged hole 532 increases the seepage amount, and the cap block 533 discharges the ink and discharges it from the bell tube 531.

[0069] The hollow roller 51 is rotatably connected to the discharge pipe 28 provided on one side of the storage mechanism 2 . The rotary motor 6 is fixedly connected to the discharge pipe 28 . The hollow roller 51 includes a roller body 511 . A rubber ring 512 is provided on the outer side of the roller body 511 .

[0070] In one embodiment, the storage mechanism 2 includes an ink storage part 21, a powder storage box 22 arranged in the ink storage part 21, a powder bin 23 is arranged in the powder storage box 22, the powder bin 23 is connected to a vacuum tank 24 through a quantitative feeder, the inner cavity of the vacuum tank 24 is connected to a vacuum pump 25, the discharge port of the vacuum tank 24 is connected to a distribution pipe 26 through an electromagnetic valve, the distribution pipe 26 is provided with a rubber sleeve 27, and the rubber sleeve 27 is mounted on the distribution mechanism 3.

[0071] During use, when the rotating motor 6 causes the dividing sleeve 32 to move, the dividing pipe 26 is connected to the dividing sleeve 32, the dividing pipe 26 can compress the rubber sleeve 27, and then the rubber sleeve 27 can provide moving space for movement, and the vacuum tank 24 makes the incoming powder float, which is conducive to separating moisture and also convenient for keeping the powder in a uniform state.

[0072] In one of the embodiments, a rotating motor 6 is provided on the dividing mechanism 3, and the dividing mechanism 3 includes an arc-shaped isolation sleeve 31. The arc-shaped isolation sleeve 31 has a lower dividing port 35 and an upper dividing port. A dividing sleeve 32 switched in the arc-shaped isolation sleeve 31 is provided in the arc-shaped isolation sleeve 31. The rotating motor 6 drives the dividing sleeve 32 to move between the lower dividing port 35 and the upper dividing port. The dividing sleeve 32 is provided with a lower discharge port and an upper discharge port 33 matching the lower dividing port 35 and the upper dividing port. An isolation plate 34 is provided in the dividing sleeve 32 near the upper discharge port 33. When the upper discharge port 33 is connected with the upper dividing port, the isolation plate 34 separates the sliding cavity 36 into a gathering cavity 37 and a dispersion cavity 36.

[0073] When in the plane printing mode, the rotating motor 6 makes the material distribution sleeve 32 move downward, and then the lower discharge port on the material distribution sleeve 32 cooperates with the lower material distribution port 35, so that the internal metal powder can be sprayed out from the lower material distribution port 35 and evenly dispersed on the surface of the base ink film layer. When the base ink film layer moves downward, a gear is provided on the isolation plate 34, which meshes with the external rack to form a driving relationship, so that the isolation plate 34 rotates, forming a relationship of communication between the gathering chamber 37 and the dispersion chamber 36, and then the metal powder can be dispersed in the arc cavity and driven out by the airflow. When the convex point is printed, the rotating motor 6 makes the material distribution sleeve 32 move upward, and the upper discharge port 33 of the upper material distribution port overlaps, and the upper discharge port 33 of the upper material distribution port is set at an equal distance, so that the metal powder can be discharged in blocks in the grid opening 521, and then when the convex point is printed, a block of metal powder that is easy to absorb and transfer heat can be formed on the contact concentration surface, thereby improving the heat dissipation efficiency.

[0074] Various modifications to these embodiments will be apparent to those skilled in the art. The general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A printing process using water-based polyurethane printing ink, characterized in that: The steps include: Step 1: Obtain the printing area of ​​the circuit substrate and extract the image of the area; Step 2: construct a printing path of the circuit substrate plane according to the extracted image and select a printing mode; Step three: the printing mode includes a flat printing mode and a convex dot printing mode; Wherein, the planar printing mode comprises the following steps: S1: forming a base ink film layer on the plane of the circuit substrate; S2: During the formation of the base ink film layer, a dispersed metal powder layer is constructed, and a middle ink film layer is constructed; S3: forming a surface ink film layer; The convex point printing mode comprises the following steps: S1: forming a grid-shaped base ink film layer on the plane of the circuit substrate; S2: before the grid-like base ink film layer is formed, metal powder is filled in the grid, and a thin sheet metal layer is printed on the surface of the circuit substrate in parallel; S3: forming a surface ink film layer; Step 4: Drying the printed layer.

2. A printing process using water-based polyurethane printing ink according to claim 1, characterized in that: Step two also includes obtaining an image using a CNN feature extraction method, and judging the situation of image spots based on the state of the extracted image. If there are no spots on the image surface, the plane printing mode of printing mode two is adopted; if there are spots on the image surface, the convex dot printing mode of printing mode one is adopted.

3. The printing process using water-based polyurethane printing ink according to claim 1, characterized in that: The ink film layer is water-based polyurethane printing ink.

4. The printing process using water-based polyurethane printing ink according to claim 1, characterized in that: The flat printing mode and the convex dot printing mode also include a printing device, which includes an operating platform (1), on which a storage mechanism (2) is arranged, and at the bottom of the storage mechanism (2), a printing surface roller (4), a material distribution mechanism (3) and a printing base roller (5) are arranged in sequence from left to right.

5. The printing device according to claim 4, characterized in that The storage mechanism (2) comprises an ink storage part (21), a powder storage box (22) arranged in the ink storage part (21), a powder bin (23) arranged in the powder storage box (22), the powder bin (23) being connected to a vacuum tank (24) through a quantitative feeder, the inner cavity of the vacuum tank (24) being connected to a vacuum pump (25), the feed port of the vacuum tank (24) being connected to a feed pipe (26) through an electromagnetic valve, the feed pipe (26) being provided with a rubber sleeve (27), and the rubber sleeve (27) being sleeved on the feed mechanism (3).

6. The printing device according to claim 5, characterized in that The material distribution mechanism (3) is provided with a rotating motor (6), and the material distribution mechanism (3) includes an arc-shaped isolation sleeve (31), the arc-shaped isolation sleeve (31) has a lower material distribution port (35) and an upper material distribution port, and the arc-shaped isolation sleeve (31) is provided with a material distribution sleeve (32) switched in the arc-shaped isolation sleeve (31), and the rotating motor (6) drives the material distribution sleeve (32) to move between the lower material distribution port (35) and the upper material distribution port, and the material distribution sleeve (32) is provided with a lower discharge port and an upper discharge port (33) matching the lower material distribution port (35) and the upper material distribution port, and an isolation plate (34) is provided in the material distribution sleeve (32) near the upper discharge port (33), and when the upper discharge port (33) is connected with the upper material distribution port, the isolation plate (34) separates the sliding cavity (36) into a gathering cavity (37) and a dispersion cavity (36).

7. The printing device according to claim 6, characterized in that The printing base roller (5) comprises a hollow roller (51), the hollow roller (51) is sleeved with a mesh screen sleeve (52), the mesh screen sleeve (52) comprises a material storage portion (522), the material storage portion (522) is provided with a plurality of mesh openings (521), a discharge plate (53) is arranged at equal intervals on the hollow roller (51), a mesh plate (54) is elastically arranged in the hollow roller (51) at the position of the discharge plate (53), both ends of the mesh plate (54) are provided with outgoing ends (541), the outgoing ends (54 1) extending into an annular notch provided on the outside of the hollow roller (51), the outward end (541) being elastically connected to the inner wall of the annular notch via a silicone pad (55), a connecting block connected to a guide block (58) being provided on the material distribution sleeve (32), an offset slide being provided in the annular notch, an offset rod (57) being provided in the offset slide, one end of the offset rod (57) being fixedly connected to an extrusion plate (56), a plurality of tightening hoops (59) being provided on the periphery of the outward ends (541), one end of the tightening hoops (59) being close to the connecting block.

8. The printing device according to claim 7, characterized in that: A plurality of feed caps are arranged on the inner side of the discharge plate (53), and the feed caps include a bell tube (531). A cap sleeve block (533) is arranged at the inner end of the bell tube (531), and a plurality of enlarged holes (532) are arranged at the waist of the bell tube (531). The circular holes on the mesh plate (54) are sleeved on the bell tube (531) to seal the enlarged holes (532).

9. The printing device according to claim 8, characterized in that The hollow roller (51) is rotatably connected to a discharge pipe (28) provided on one side of the storage mechanism (2), and the rotary motor (6) is fixedly connected to the discharge pipe (28). The hollow roller (51) includes a roller body (511), and a rubber ring (512) is provided on the outer side surface of the roller body (511).

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