Profile control device for pneumatic direct-write printheads and its applications.

Abstract

A profile control device for a pneumatic direct-write printhead and its applications is provided. [Solution] The present invention belongs to the direct-write technical field, and in particular relates to a profile control device for a pneumatic direct-write printhead and its applications. The present invention provides a new profile control device that can be attached to a direct-write printhead, thereby significantly reducing the length of the excess ink deposition edge and improving the utilization rate of the substrate. The line height difference of the printout obtained by printing with the profile control device of the present invention is small, and the resulting printout has higher accuracy and quality. Furthermore, the profile control device of the present invention has a simple structure, low manufacturing costs, is easy to install, is detachable from the direct-write printhead, and is highly flexible.

Description

[Technical Field]

[0001] The present invention relates to the direct write technology field, and more particularly to a profile control system for a pneumatic direct write printhead and its application. [Background technology]

[0002] Direct Ink Writing (DIW) is a novel, high-precision additive manufacturing (ADM) 3D printing technology that uses a controllable nozzle system to precisely spray viscous ink onto a target surface and then hardens the ink by thermal curing or crosslinking to form a three-dimensional structure. Due to its unique advantages, direct ink writing has shown great potential for application in fields such as biomedical engineering, microdevice manufacturing, aerospace and defense, and the display industry. Specifically, direct ink writing offers the following advantages: high accuracy and resolution, enabling the construction of complex geometric shapes, microstructures, and micro-sized structures. It has been widely used in the fabrication of complex structures and nano-level materials, with superior material quality. Direct ink writing technology achieves high printing speeds and meets the application needs of the current printing market. Compared to traditional inkjet and laser printing technologies, direct ink writing technology uses ink more economically and efficiently, resulting in lower equipment operating costs. Direct ink writing has a very wide range of applications because it can print different types of ink, including color ink, fluorescent ink, and metallic ink. Its application flexibility is high, and by using different types of ink and printing substrates, the performance properties of the final direct ink writing product, such as hardness, elasticity, and conductivity, can be adjusted. Furthermore, compared to traditional printing technologies, direct ink writing is very quiet during operation and does not cause noise interference.

[0003] Ink ejection methods for direct ink writing are mainly pneumatic, mechanical, and electromagnetic. So-called pneumatic ink ejection involves applying air pressure to force ink into a nozzle or syringe, and controlling the magnitude of the air pressure and the nozzle position to control the ink extrusion speed and flow rate. So-called mechanical ink ejection involves controlling the ink extrusion and flow rate through a mechanical device, and a typical mechanical ink ejection device has a screw extrusion structure. Electromagnetic ink ejection involves using electromagnetic force to force ink into a nozzle or syringe, and this method usually uses an electromagnetic driver or solenoid valve to control the ink extrusion speed and flow rate. Considering the wear and energy consumption of mechanical and electromagnetic ink ejection, the most common and widely used direct ink writing devices on the market today use pneumatic ejection. Pneumatic ink ejection has the following advantages: the pneumatic ejection method can control the ink flow rate and extrusion volume by adjusting the air pressure, resulting in higher accuracy during the printing process; the pneumatic ejection method is highly adjustable, allowing the ink ejection rate and flow rate to be adjusted as needed, and ink ejection to be started and stopped instantly, thereby achieving the best printing results under different printing requirements.

[0004] While pneumatic direct writing has many advantages as described above, during the printing process, the print head movement speed at acceleration / deceleration positions, such as the start stage of pneumatic direct writing (the stage where the print head gradually accelerates to a constant speed) and the end stage (the stage where the print head gradually decelerates from a constant speed to stop printing), is slower than the printing speed during the constant-speed printing stage. Therefore, if the air pressure is kept constant, excess ink will be deposited on the surface of the printing substrate at the acceleration and deceleration positions, resulting in long excess ink deposits. To minimize the length of the excess ink deposits, improve substrate utilization, narrow the border width of the final print, and reduce printing costs, a common practical solution is to rapidly switch air pressure, i.e., apply air pressure to the ink with a delay near the start of the acceleration stage and stop applying air pressure to the ink early near the end of the deceleration stage, thereby ensuring a relative match between the ink flow rate and the print head movement speed. However, on the one hand, the pneumatic system has a delay effect, and in the case of high-speed printing, the direct writing device cannot guarantee that the ink flow rate and the moving speed are exactly the same, so this method cannot effectively solve the technical problem of the long excess ink accumulation side of the product. On the other hand, when the air pressure is switched frequently, the actual supply pressure cannot reach a stable state, so the line height difference of the resulting print is large and the accuracy is not sufficient. Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention aims to provide a profile control device for a pneumatic direct write print head with high printing accuracy and its application, which can be achieved by the following technical means. [Means for solving the problem]

[0006] a material control assembly including a suction slit extending through the second surface and a suction member communicating with an end of the suction slit proximal to the first surface; a liquid guide opening formed on the side of the suction slit proximal to the second surface for guiding ink on a droplet ejection surface of the direct-write printhead to flow along the suction slit; and a diameter of the second mounting opening greater than a diameter of the droplet ejection ports of the direct-write printhead.

[0007] The present invention provides a new profile control device that can be attached to a direct-write printhead, thereby significantly shortening the length of the excess ink deposition edge, avoiding ink waste and reducing printing costs. The profile control device of the present invention has a small line height difference on the printout, resulting in higher accuracy and superior quality. Furthermore, the profile control device of the present invention has a simple structure, low manufacturing costs, is easy to install, is detachable from the direct-write printhead, and is highly flexible.

[0008] Specifically, in this technical solution, the profile control device of the present invention has a first surface, a second surface, a mounting hole penetrating the first and second surfaces, and first and second mounting holes that fit into the mounting holes, making it easy to install a direct-write printhead. During the installation process, the droplet ejection ports of the direct-write printhead simply pass through the first mounting hole and then the second mounting hole, and then fit into the mounting hole.

[0009] The profile control device of the present invention effectively solves the problem of excessively long excess ink accumulation on printed products in the prior art by providing a liquid guide port, a suction slit communicating with the liquid guide port in sequence, and a suction member on the second surface, and by restricting the relationship between the second mounting port and the diameter of the droplet ejection ports of the direct-write printhead. Taking a direct-write printhead in a deceleration phase as an example, the pressure applied to the ink remains constant. When the direct-write printhead is in a deceleration phase, the ink on the droplet ejection port surface of the direct-write printhead continues to accumulate until it contacts the liquid guide port. The suction member then sucks the ink out along the liquid guide port and the suction slit. At this point, no ink remains on the surface of the direct-write printhead, shortening the excess ink accumulation and allowing the ink sucked up by the suction member to be reused. It should be noted that the present invention adjusts the diameter relationship between the second mounting opening and the droplet ejection opening of the direct-write print head so that the suction member is activated to suck up ink only when a certain amount of ink has accumulated on the surface of the droplet ejection opening of the direct-write print head. This effectively prevents the suction member from indiscriminately sucking up ink on the surface of the droplet ejection opening of the direct-write print head, thereby ensuring the quality of the printed matter at the constant speed.

[0010] Preferably, the suction slit is arranged coaxially with the second mounting opening.

[0011] In principle, any suction slit that can establish communication between the liquid guide port and the suction member can satisfy the requirements for the suction member to suck up ink. Therefore, the suction slit of the present invention can take the form of one or more holes located near the second mounting opening, or it can be an arc-shaped suction slit located near the second mounting opening. In this technical solution, the suction slit is an annular suction slit that surrounds the second mounting opening and is coaxial with the second mounting opening. The annular suction slit provides a larger ink suction space, making it suitable for direct-write printheads with large ink accumulation volumes. On the other hand, it also increases the contact surface between the liquid guide port and the ink. Therefore, as ink accumulates in the central droplet ejection port of the direct-write printhead, it comes into contact with the liquid guide ports evenly distributed around it. This improves the ink suction effect of the suction member, reduces the amount of ink remaining on the droplet ejection port surface of the direct-write printhead, and further shortens the length of the excess ink accumulation edge.

[0012] Preferably, the inner surface of the mounting hole is provided with a temperature control assembly for controlling the surface temperature of the direct-write printhead.

[0013] Through research, the applicant has found that the uniformity of the surface temperature of the direct-write printhead not only affects the uniformity of the ink, but also the amount of ink ejection. This technical solution, by installing a temperature control assembly on the inner surface of the mounting hole, can prevent changes in the ejection amount due to temperature fluctuations during the continuous printing process of the direct-write printhead, thereby improving the accuracy of the printed product obtained after printing.

[0014] More preferably, the temperature control assembly includes a temperature adjustment member and a temperature sensor for measuring the surface temperature of the pneumatic direct-write printhead.

[0015] This technical solution includes a temperature control element for adjusting the surface temperature of the direct-write printhead and a temperature sensor for measuring the surface temperature of the pneumatic direct-write printhead. The close cooperation between the temperature control element and the temperature sensor narrows the range of fluctuation in the surface temperature of the direct-write printhead, resulting in more uniform ink ejection from the droplet ejection ports of the direct-write printhead and higher print quality. Specifically, the temperature control element can be selected from devices capable of adjusting the surface temperature of the direct-write printhead, such as a heating wire, water circulation piping, or Peltier element.

[0016] A pneumatic direct-write stylus comprising a profile control device according to any one of the preceding claims.

[0017] Preferably, the pneumatic direct-write print needle comprises a head holder and a direct-write print head mounted on the head holder, the direct-write print head having a droplet ejection port at an end thereof remote from the head holder, and the cross-sectional area of ​​the direct-write print head continuously decreases along the ink flow direction of the droplet ejection port.

[0018] This technical solution limits the shape of the direct-write printhead to which the profile control device is applied, which on the one hand improves the overall mechanical strength of the direct-write printhead, thereby extending the life of the direct-write printhead; on the other hand, when a temperature control assembly is provided on the surface of the direct-write printhead, the ink temperature in the direct-write printhead can be further controlled before the ink is extruded, thereby reducing the impact of the ink temperature on the flow rate of the droplet ejection outlets of the direct-write printhead, thereby improving the accuracy of the printed matter obtained after printing.

[0019] A direct-write device comprising a pneumatic direct-write stylus according to any one of the preceding claims.

[0020] Preferably, the direct-write device further comprises an elevator assembly for moving the pneumatic direct-write stylus up and down.

[0021] A method for using the direct writing device includes the steps of lifting the direct writing print head during acceleration and deceleration phases of direct writing so that the ink on the surface of the direct writing print head does not come into contact with the printing substrate, opening the suction member, and sucking out the ink that comes into contact with the liquid guide port along the liquid guide port and the suction slit in sequence.

[0022] This technical solution uses a liquid guide hole structure in combination with a method of lifting the direct-write printhead, so that during the process of lifting the direct-write printhead based on the Coanda effect, ink on the surface of the direct-write printhead continues to accumulate upward along the liquid guide hole, resulting in a better overall ink absorption effect and a shorter excess ink accumulation side.

[0023] The method for using the direct writing device includes the steps of closing the supply air pressure, opening the suction member, and sucking ink contacting the liquid guide port along the liquid guide port and the suction slit in sequence during the acceleration and deceleration phase of direct writing.

[0024] Preferably, the method of using the direct write device comprises: A step S1 in which a monitoring probe of the temperature sensor collects temperature data of the surface of the direct-write printhead, and then uploads the temperature data to a controller via a communication module of the temperature sensor; and The controller analyzes the temperature data and adjusts the temperature of the direct-write printhead surface by instructing the temperature adjustment member to increase and decrease the temperature based on the analysis, step S2. [Effects of the Invention]

[0025] The present invention has the following advantageous effects compared to the prior art: The present invention provides a novel profile control device that can be attached to a direct-write printhead, significantly shortening the length of the excess ink deposition edge and improving substrate utilization. The profile control device of the present invention reduces line height differences in prints, resulting in higher accuracy and quality. The profile control device of the present invention has a simple structure, low manufacturing costs, easy installation, is detachable from a direct-write printhead, and is highly flexible. Specifically, the profile control device of the present invention facilitates installation of a direct-write printhead by providing a first surface, a second surface, a mounting hole penetrating the first and second surfaces, and first and second mounting holes that fit the mounting holes. The profile control device of the present invention effectively solves the problem of excessively long excess ink deposition edges on prints in the prior art by providing a liquid guide port on the second surface, a suction slit and suction member that sequentially communicate with the liquid guide port, and restricting the relationship between the second mounting hole and the diameter of the droplet ejection orifices of the direct-write printhead. Furthermore, by adjusting the diameter relationship between the second mounting hole and the droplet ejection orifices of the direct-write printhead, the suction member is activated to suck up ink only when a certain amount of ink has accumulated on the surface of the droplet ejection orifices of the direct-write printhead, effectively preventing the suction member from indiscriminately sucking up ink on the surface of the droplet ejection orifices of the direct-write printhead, thereby ensuring the quality of printed products at constant speeds.In addition, by providing a temperature control assembly on the inner surface of the mounting hole, the present invention can prevent changes in the ejection flow rate due to temperature fluctuations during the continuous printing process of the direct-write printhead, thereby improving the accuracy of the printed products obtained after printing.

[0026] In order to clearly explain the embodiments, the accompanying drawings will be briefly described below. [Brief explanation of the drawings]

[0027] [Figure 1] FIG. 10 is a cross-sectional view of a profile control device according to a third embodiment. [Figure 2] FIG. 10 is a cross-sectional view of a direct-write printing stylus according to a fourth embodiment. [Figure 3] 10 is a diagram showing the printing path of the direct writing device of Example 6, in which the white path portion is the portion where the direct writing print needle is lifted. FIG. [Figure 4] FIG. 10 is an enlarged view of a local profile of the finished print obtained in Example 6. [Figure 5] 10 is a graph showing line height data at different positions within the effective area of ​​the print obtained in Example 6. [Figure 6] FIG. 2 is an enlarged view of a local profile of the finished print obtained in Comparative Example 1. [Figure 7] 10 is a graph showing line height data at different positions within the effective area of ​​the print obtained in Comparative Example 1. DETAILED DESCRIPTION OF THE INVENTION

[0028] The present invention will be further described below with reference to specific embodiments. Those skilled in the art will be able to practice the present invention based on these descriptions. It should be noted that the embodiments of the present invention mentioned below generally represent only some of the embodiments of the present invention, and do not necessarily represent all of the embodiments. Any other embodiments obtained by those skilled in the art based on the embodiments of the present invention without any creative activity are also within the scope of protection of the present invention.

[0029] Example 1 This embodiment discloses a profile control device for a pneumatic direct-write printhead, the profile control device comprising: The profile control device has a first surface 1 and a second surface 2 arranged corresponding to each other above and below, and a mounting hole 3 that penetrates the first surface 1 and the second surface 2 and is used to mount a direct-write printhead 7. One end of the mounting hole 3 and the first surface 1 define a first mounting opening 11, and the other end of the mounting hole 3 and the second surface 2 define a second mounting opening 21. The profile control device of this embodiment has the first surface 1, the second surface 2, the mounting hole 3 that penetrates the first surface 1 and the second surface 2, and the first mounting opening 11 and the second mounting opening 21 that fit into the mounting hole 3, thereby providing great convenience for subsequent mounting of the direct-write printhead 7. Specifically, the process of mounting the profile control device simply involves passing the droplet ejection port 71 of the direct-write printhead 7 through the first mounting opening 11 and the second mounting opening 21 in order, and fitting the profile control device into the mounting opening 3. At this point, the first mounting opening 11, the second mounting opening 21, and the mounting hole 3 come into close contact with some or all of the sides of the direct-write print head 7, completing the installation. The installation method for the above device is simple, does not require any structural modifications to the pneumatic direct-write print head 7, and is highly flexible in use, making it easy to inspect and replace the profile control device. To further facilitate installation, the profile control device in this embodiment has a truncated cone shape and is made of rubber.

[0030] To suck up ink on the surface at one end of the droplet ejection port 71 of the direct-write printhead 7, the profile control device of this embodiment also includes a material control assembly 4. The material control assembly 4 includes a suction slit 41 penetrating the second surface 2 and a suction member 42 communicating with the end of the suction slit 41 closer to the first surface 1, and a liquid guide port 43 is formed on the side of the suction slit 41 closer to the second surface 2, which guides the ink on the surface at one end of the droplet ejection port 71 of the direct-write printhead 7 to flow along the suction slit 41. In this embodiment, in order to simplify the internal structure of the profile control device and to some extent reduce the difficulty of manufacturing the device, the suction slits 41 are two holes penetrating the second surface 2. Furthermore, during the acceleration and deceleration stages, the ink accumulated on the surface of the droplet ejection port 71 of the direct write print head 7 quickly comes into contact with the liquid guide port 43, further shortening the length of the excess ink accumulation side, so that the second surface 2 that contacts the side of the liquid guide port 43 away from the center of the second mounting port 21 is higher than the second surface 2 that is closer to the center of the second mounting port 21.

[0031] Furthermore, if the second surface 2 and the droplet ejection ports 71 of the direct-write print head 7 are relatively close to each other, or even concentrically arranged, the ejected ink will inevitably come into contact with the second surface 2, particularly with the liquid guide ports 43 located near the droplet ejection ports 71. This will, on the one hand, affect the ink profile during the constant speed or acceleration / deceleration phases of printing, and, on the other hand, cause the ink at a normal flow rate to be easily sucked out by the suction member 42. Therefore, in order to prevent the suction member 42 from indiscriminately sucking up the ink on the surface of the droplet discharge port 71 of the direct-write print head 7, while ensuring the quality of the printed matter in the constant speed phase, the length of the excess ink accumulation side is shortened, and printing waste is reduced, the diameter of the second mounting port portion 21 in this embodiment is made larger than the diameter of the droplet discharge port 71 of the direct-write print head. This means that by adjusting the liquid level difference between the second surface 2 and the droplet discharge port 71, the suction member will operate to suck up the ink only when a certain amount of ink has accumulated on the surface of the droplet discharge port 71 of the direct-write print head 7.

[0032] Example 2 This embodiment discloses a profile control device for a pneumatic direct-write printhead, the profile control device comprising: The profile control device has a first surface 1 and a second surface 2 arranged corresponding to each other above and below, and a mounting hole 3 that penetrates the first surface 1 and the second surface 2 and is used to mount a direct-write printhead 7. One end of the mounting hole 3 and the first surface 1 define a first mounting opening 11, and the other end of the mounting hole 3 and the second surface 2 define a second mounting opening 21. The profile control device of this embodiment has the first surface 1, the second surface 2, the mounting hole 3 that penetrates the first surface 1 and the second surface 2, and the first mounting opening 11 and the second mounting opening 21 that fit into the mounting hole 3, thereby providing great convenience for subsequent mounting of the direct-write printhead 7. Specifically, the process of mounting the profile control device simply involves passing the droplet ejection port 71 of the direct-write printhead 7 through the first mounting opening 11 and the second mounting opening 21 in order, and fitting the profile control device into the mounting opening 3. At this point, the first mounting opening 11, the second mounting opening 21, and the mounting hole 3 come into close contact with some or all of the sides of the direct-write print head 7, completing the installation. The installation method for the above device is simple, does not require any structural modifications to the pneumatic direct-write print head 7, and is therefore highly flexible in use and convenient for inspecting and replacing the profile control device. The profile control device in this embodiment has a rectangular parallelepiped exterior and is made of aluminum.

[0033] To suck up ink on the surface at one end of the droplet ejection orifices 71 of the direct-write printhead 7, the profile control device of this embodiment also includes a material control assembly 4. The material control assembly 4 includes a suction slit 41 penetrating the second surface 2 and a suction member 42 communicating with the end of the suction slit 41 closest to the first surface 1. A liquid guide port 43 is formed on the side of the suction slit 41 closest to the second surface 2, guiding the ink on the surface at one end of the droplet ejection orifices 71 of the direct-write printhead 7 to flow along the suction slit 41. In this embodiment, the suction slit 41 is annular, surrounding the second mounting port 21 and positioned coaxially with the second mounting port 21. The annular suction slit 41 provides a larger storage space for sucking up ink, making it suitable for use with direct-write printheads 7 with a large ink reservoir. On the other hand, the contact area between the liquid guide openings 43 and the ink can be increased, so that as ink continues to accumulate at the central droplet outlet 71 of the direct-write print head, it will come into contact with the evenly distributed liquid guide openings 43 around it, which allows the suction member 42 to more effectively suck up ink, reducing the amount of ink remaining on the surface of the direct-write print head droplet outlet 71 and further shortening the length of the excess ink accumulation side. Furthermore, during the acceleration and deceleration phases, the ink accumulated on the surface of the droplet outlet 71 of the direct-write print head 7 quickly comes into contact with the liquid guide openings 43, further shortening the length of the excess ink accumulation side, so that the second surface 2 of the liquid guide opening 43 that contacts the side away from the center of the second mounting opening 21 is higher than the second surface 2 that is closer to the center of the second mounting opening 21.

[0034] Furthermore, if the second surface 2 and the droplet ejection ports 71 of the direct-write print head 7 are relatively close to each other, or even concentrically arranged, the ejected ink will inevitably come into contact with the second surface 2, particularly with the liquid guide ports 43 located near the droplet ejection ports 71. This will, on the one hand, affect the ink profile during the constant speed or acceleration / deceleration phases of printing, and, on the other hand, cause the ink at a normal flow rate to be easily sucked out by the suction member 42. Therefore, in order to prevent the suction member 42 from indiscriminately sucking up the ink on the surface of the droplet discharge port 71 of the direct-write print head 7, while ensuring the quality of the printed matter in the constant speed phase, the length of the excess ink accumulation side is shortened, and printing waste is reduced, the diameter of the second mounting port portion 21 in this embodiment is made larger than the diameter of the droplet discharge port 71 of the direct-write print head. This means that by adjusting the liquid level difference between the second surface 2 and the droplet discharge port 71, the suction member will operate to suck up the ink only when a certain amount of ink has accumulated on the surface of the droplet discharge port 71 of the direct-write print head 7.

[0035] Example 3 This embodiment discloses a profile control device for a pneumatic direct-write printhead, the profile control device comprising: The profile control device has a first surface 1 and a second surface 2 arranged corresponding to each other above and below, and a mounting hole 3 that penetrates the first surface 1 and the second surface 2 and is used to mount a direct-write printhead 7. One end of the mounting hole 3 and the first surface 1 define a first mounting opening 11, and the other end of the mounting hole 3 and the second surface 2 define a second mounting opening 21. The profile control device of this embodiment has the first surface 1, the second surface 2, the mounting hole 3 that penetrates the first surface 1 and the second surface 2, and the first mounting opening 11 and the second mounting opening 21 that fit into the mounting hole 3, thereby providing great convenience for subsequent mounting of the direct-write printhead 7. Specifically, the process of mounting the profile control device simply involves passing the droplet ejection port 71 of the direct-write printhead 7 through the first mounting opening 11 and the second mounting opening 21 in order, and fitting the profile control device into the mounting opening 3. At this point, the first mounting opening 11, the second mounting opening 21, and the mounting hole 3 come into close contact with some or all of the sides of the direct-write print head 7, completing the installation. The installation method for the above device is simple, does not require any structural modifications to the pneumatic direct-write print head 7, and is therefore highly flexible in use and convenient for inspecting and replacing the profile control device. The profile control device in this embodiment has a truncated cone shape and is made of copper.

[0036] To suck up ink on the surface at one end of the droplet ejection orifices 71 of the direct-write printhead 7, the profile control device of this embodiment also includes a material control assembly 4. The material control assembly 4 includes a suction slit 41 penetrating the second surface 2 and a suction member 42 communicating with the end of the suction slit 41 closest to the first surface 1. A liquid guide port 43 is formed on the side of the suction slit 41 closest to the second surface 2, guiding the ink on the surface at one end of the droplet ejection orifices 71 of the direct-write printhead 7 to flow along the suction slit 41. In this embodiment, the suction slit 41 is annular, surrounding the second mounting port 21 and positioned coaxially with the second mounting port 21. The annular suction slit 41 provides a larger storage space for sucking up ink, making it suitable for use with direct-write printheads 7 with a large ink reservoir. On the other hand, the contact area between the liquid guide openings 43 and the ink can be increased, so that as ink continues to accumulate at the central droplet outlet 71 of the direct-write print head, it will come into contact with the evenly distributed liquid guide openings 43 around it, which allows the suction member 42 to more effectively suck up ink, reducing the amount of ink remaining on the surface of the direct-write print head droplet outlet 71 and further shortening the length of the excess ink accumulation side. Furthermore, during the acceleration and deceleration phases, the ink accumulated on the surface of the droplet outlet 71 of the direct-write print head 7 quickly comes into contact with the liquid guide openings 43, further shortening the length of the excess ink accumulation side, so that the second surface 2 of the liquid guide opening 43 that contacts the side away from the center of the second mounting opening 21 is higher than the second surface 2 that is closer to the center of the second mounting opening 21. If the second surface 2 and the droplet ejection ports 71 of the direct-write printhead 7 are relatively close to each other, or even concentrically arranged, the ejected ink will inevitably come into contact with the second surface 2, particularly with the liquid guide ports 43 located near the droplet ejection ports 71. This affects the ink profile during the constant speed or acceleration / deceleration phases of printing, while the ink at a normal flow rate is easily sucked out by the suction member 42.Therefore, in order to prevent the suction member 42 from indiscriminately sucking up the ink on the surface of the droplet discharge port 71 of the direct-write print head 7, while ensuring the quality of the printed matter in the constant speed phase, the length of the excess ink accumulation side is shortened, and printing waste is reduced, the diameter of the second mounting port portion 21 in this embodiment is made larger than the diameter of the droplet discharge port 71 of the direct-write print head. This means that by adjusting the liquid level difference between the second surface 2 and the droplet discharge port 71, the suction member will operate to suck up the ink only when a certain amount of ink has accumulated on the surface of the droplet discharge port 71 of the direct-write print head 7.

[0037] To prevent changes in ink flow rate due to fluctuations in the surface temperature of the direct-write printhead 7 during continuous printing by the direct-write printhead 7, a temperature control assembly 5 for controlling the surface temperature of the direct-write printhead 7 is installed on the inner surface of the mounting hole 3 of the profile control device in this embodiment. The temperature control assembly 5 includes a temperature adjustment member 51 for controlling the surface temperature of the direct-write printhead 7 and a temperature sensor 52 for measuring the surface temperature of the pneumatic direct-write printhead 7. To adequately adjust the surface temperature of the direct-write printhead 7, the temperature adjustment member 51 in this embodiment uses an electric heating wire.

[0038] Example 4 This embodiment discloses a pneumatic direct writing stylus, which includes: The printer includes a head holder 6 and a direct-write printhead 7 mounted on the head holder 6. A droplet ejection port 71 is provided at the end of the direct-write printhead 7 away from the head holder 6. The cross-sectional area of ​​the direct-write printhead 7 continuously decreases along the ink flow direction of the droplet ejection port 71. In this embodiment, the shape of the direct-write printhead 7 is specially designed to improve the mechanical strength of the direct-write printhead 7, thereby extending its lifespan. Meanwhile, the temperature adjustment member 41 further controls the ink temperature within the direct-write printhead 7 before ejecting the ink, thereby reducing the impact of the ink temperature on the ink flow rate of the droplet ejection port 71 of the direct-write printhead 7, thereby improving the accuracy of the printed product. A profile control device is mounted on the direct-write printhead 7, and the profile control device: The profile control device has a first surface 1 and a second surface 2 arranged corresponding to each other above and below, and a mounting hole 3 that penetrates the first surface 1 and the second surface 2 and is used to mount a direct-write printhead 7. One end of the mounting hole 3 and the first surface 1 define a first mounting opening 11, and the other end of the mounting hole 3 and the second surface 2 define a second mounting opening 21. The profile control device of this embodiment has the first surface 1, the second surface 2, the mounting hole 3 that penetrates the first surface 1 and the second surface 2, and the first mounting opening 11 and the second mounting opening 21 that fit into the mounting hole 3, thereby providing great convenience for subsequent mounting of the direct-write printhead 7. Specifically, the process of mounting the profile control device simply involves passing the droplet ejection port 71 of the direct-write printhead 7 through the first mounting opening 11 and the second mounting opening 21 in order, and fitting the profile control device into the mounting opening 3. At this point, the first mounting opening 11, the second mounting opening 21, and the mounting hole 3 come into close contact with some or all of the sides of the direct-write print head 7, completing the installation. The installation method for the above device is simple, does not require any structural modifications to the pneumatic direct-write print head 7, and is highly flexible in use, making it easy to inspect and replace the profile control device. To further facilitate installation, the profile control device in this embodiment has a truncated cone shape and is made of rubber.

[0039] To suck up ink on the surface at one end of the droplet ejection orifices 71 of the direct-write printhead 7, the profile control device of this embodiment also includes a material control assembly 4. The material control assembly 4 includes a suction slit 41 penetrating the second surface 2 and a suction member 42 communicating with the end of the suction slit 41 closest to the first surface 1. A liquid guide port 43 is formed on the side of the suction slit 41 closest to the second surface 2, guiding the ink on the surface at one end of the droplet ejection orifices 71 of the direct-write printhead 7 to flow along the suction slit 41. In this embodiment, the suction slit 41 is annular, surrounding the second mounting port 21 and positioned coaxially with the second mounting port 21. The annular suction slit 41 provides a larger storage space for sucking up ink, making it suitable for use with direct-write printheads 7 with a large ink reservoir. On the other hand, the contact area between the liquid guide openings 43 and the ink can be increased, so that as ink continues to accumulate at the central droplet outlet 71 of the direct-write print head, it will come into contact with the evenly distributed liquid guide openings 43 around it, which allows the suction member 42 to more effectively suck up ink, reducing the amount of ink remaining on the surface of the direct-write print head droplet outlet 71 and further shortening the length of the excess ink accumulation side. Furthermore, during the acceleration and deceleration phases, the ink accumulated on the surface of the droplet outlet 71 of the direct-write print head 7 quickly comes into contact with the liquid guide openings 43, further shortening the length of the excess ink accumulation side, so that the second surface 2 of the liquid guide opening 43 that contacts the side away from the center of the second mounting opening 21 is higher than the second surface 2 that is closer to the center of the second mounting opening 21. If the second surface 2 and the droplet ejection ports 71 of the direct-write printhead 7 are relatively close to each other, or even concentrically arranged, the ejected ink will inevitably come into contact with the second surface 2, particularly with the liquid guide ports 43 located near the droplet ejection ports 71. This affects the ink profile during the constant speed or acceleration / deceleration phases of printing, while the ink at a normal flow rate is easily sucked out by the suction member 42.Therefore, in order to prevent the suction member 42 from indiscriminately sucking up the ink on the surface of the droplet discharge port 71 of the direct-write print head 7, while ensuring the quality of the printed matter in the constant speed phase, the length of the excess ink accumulation side is shortened, and printing waste is reduced, the diameter of the second mounting port portion 21 in this embodiment is made larger than the diameter of the droplet discharge port 71 of the direct-write print head. This means that by adjusting the liquid level difference between the second surface 2 and the droplet discharge port 71, the suction member will operate to suck up the ink only when a certain amount of ink has accumulated on the surface of the droplet discharge port 71 of the direct-write print head 7.

[0040] To prevent changes in ink flow rate due to fluctuations in the surface temperature of the direct-write printhead 7 during continuous printing by the direct-write printhead 7, a temperature control assembly 5 for controlling the surface temperature of the direct-write printhead 7 is installed on the inner surface of the mounting hole 3 of the profile control device in this embodiment. The temperature control assembly 5 includes a temperature adjustment member 51 for controlling the surface temperature of the direct-write printhead 7 and a temperature sensor 52 for measuring the surface temperature of the pneumatic direct-write printhead 7. To adequately adjust the surface temperature of the direct-write printhead 7, the temperature adjustment member 51 in this embodiment uses an electric heating wire.

[0041] Example 5 This embodiment discloses a direct writing device including the pneumatic direct writing stylus described in embodiment 4 and an elevator assembly for moving the pneumatic direct writing stylus up and down. Other configurations of the direct writing device are the same as or similar to those of the prior art, and therefore detailed descriptions thereof will be omitted here.

[0042] Example 6 This embodiment discloses a printing method for reciprocating printing using the direct writing device described in the fifth embodiment, and the printing path is shown in FIG. 3. In this embodiment, the printing speed of the direct writing print head 7 in the constant speed stage is 200 mm / s, and the acceleration in the acceleration / deceleration stage is 2 m / s. 2When the printing speed of the direct-write printhead 7 is slower than the constant speed stage, ink continues to accumulate on the surface of the droplet ejection ports 71 of the direct-write printhead 7. At this time, the lifting assembly starts to lift the direct-write printhead 7 so that the ink on the surface of the direct-write printhead 7 does not come into contact with the printing substrate, and the suction member 42 starts to operate. When a certain amount of ink accumulates on the surface of the droplet ejection ports 71 of the direct-write printhead 7 and the ink comes into contact with the liquid guide port 43, the suction member 42 sucks up the ink from the droplet ejection ports 71 and then sucks it out along the liquid guide port 43 and the suction slit 41. After being sucked out, no ink droplet marks remain on the surface of the printing substrate, and the recovered ink can be reused.

[0043] In this embodiment, the temperature control assembly 5 is also adjusted to further improve the accuracy of the printed product. Specifically, the monitoring probe of the temperature sensor 52 collects temperature data on the surface of the direct-write print head 7, and then uploads the temperature data to the controller via the communication module of the temperature sensor 52. The controller analyzes the temperature data and, based on the analysis result, instructs the temperature adjustment member 51 to increase or decrease the temperature, thereby regulating the temperature on the surface of the direct-write print head 7.

[0044] Example 7 This embodiment discloses a printing method for reciprocating printing using the direct writing device described in the fifth embodiment, and the printing path is shown in FIG. 3. In this embodiment, the printing speed of the direct writing print head 7 in the constant speed stage is 200 mm / s, and the acceleration in the acceleration / deceleration stage is 2 m / s. 2 When the printing speed of the direct-write printhead 7 is slower than the constant speed stage, ink continues to accumulate on the surface of the droplet ejection ports 71 of the direct-write printhead 7. At this time, the supply air pressure is turned off, and due to the delayed response of the air pressure, some of the ink on the surface of the direct-write printhead 7 is still slowly pushed out, causing the suction member 42 to start sucking up the ink from the droplet ejection ports 71, and the ink is sequentially sucked out along the liquid guide port 43 and the suction slit 41. After being sucked out, no ink droplet marks remain on the surface of the printing substrate, and the recovered ink can be reused.

[0045] In this embodiment, the temperature control assembly 5 is also adjusted to further improve the accuracy of the printed product. Specifically, the monitoring probe of the temperature sensor 52 collects temperature data on the surface of the direct-write print head 7, and then uploads the temperature data to the controller via the communication module of the temperature sensor 52. The controller analyzes the temperature data and, based on the analysis result, instructs the temperature adjustment member 51 to increase or decrease the temperature, thereby regulating the temperature on the surface of the direct-write print head 7.

[0046] (Comparative Example 1) Comparative Example 1 is a direct writing device that does not have the profile control device of the present invention installed. The printing path of the direct writing device in Comparative Example 1 differs from that of the Examples in that the direct writing print head 7 is not lifted during the acceleration / deceleration phase, but the printing speed and acceleration are the same as those of Example 6.

[0047] <Performance test> For the prints obtained in Example 6 and Comparative Example 1, the profile analysis of the excess ink deposition side and the line height data measurement of the uniform speed effective printing area were carried out, and the results were plotted in graphs to obtain FIGS.

[0048] 4 and 6, when observing the enlarged local profiles of the prints obtained with the direct writing devices of Example 6 and Comparative Example 1, it can be seen that the length of the excess ink deposition edge of the prints obtained with Comparative Example 1 reaches 10 mm, whereas the length of the excess ink deposition edge of the prints obtained with the present invention is only 1 / 5 of the length of the excess ink deposition edge of Comparative Example 1. It can be seen that by attaching a profile control device to the direct writing print head and combining it with a special usage method, the present invention effectively solves the problem of the excess ink deposition edge of the conventional prints being too long, and significantly reduces ink waste during the printing process.

[0049] 5 and 7, the line height differences between the same line in different printing areas of the prints obtained in Example 6 and Comparative Example 1, and the line height differences between different lines in the same printing area, are observed. The line heights between multiple printed lines in the same area of ​​the prints obtained in Comparative Example 1 are relatively dispersed, and the line height differences between the same printed lines in different areas are relatively large. This indicates that the profile shows uneven heights of the same lines within the effective area, which is consistent with the rough profile of the constant-speed effective printing area in FIG. 6. This indicates that the conventional direct writing device not only has long excess ink deposition edges, but also has poor overall printing accuracy. FIG. 5 also shows that the line height concentration between each printed line in the prints obtained by the present invention is relatively high, and the line height differences between different areas of the same printed line are relatively small. By installing a profile control device on the direct writing printhead and combining it with a special usage method, the problem of long excess ink deposition edges in conventional prints can be effectively solved, and printing accuracy can be further improved.

[0050] In this specification, terms such as "1: first surface, 2: second surface, 3: mounting hole, 11: first mounting port, 21: second mounting port, 4: material control assembly, 41: suction slit, 42: suction member, 43: liquid guide port, 5: temperature control assembly, 51: temperature adjustment member, 52: temperature sensor, 6: head holder, 7: direct-write printhead, 71: droplet ejection port," which are reference numerals in the drawings, are frequently used, but the use of other terms is not excluded. These terms are used merely to more conveniently describe and interpret the essence of the present invention, and any interpretation of them as additional limitations would be contrary to the spirit of the present invention. [Explanation of symbols]

[0051] 1 1st surface 11 First mounting opening 2 2nd surface 21 2nd mounting opening 3 mounting holes 4 Material Control Assembly 41 Suction slit 42 Suction member 43 Liquid inlet 5 Temperature Control Assembly 51 Temperature control material 52 Temperature Sensor 6 Head holder 7 Direct Write Printhead 71 Droplet outlet

Claims

1. 1. A profile control device for a pneumatic direct-write printhead, the profile control device comprising: correspondingly arranged first and second surfaces; and a mounting hole extending through the first and second surfaces for mounting the direct-write printhead; one end of the mounting hole and the first surface defining a first mounting opening; and the other end of the mounting hole and the second surface defining a second mounting opening. The profile control device also comprises a material control assembly including a suction slit extending through the second surface and a suction member communicating with an end of the suction slit proximal to the first surface, the suction slit having a liquid guide port formed on a side proximal to the second surface for guiding ink on a droplet ejection orifice surface of the direct-write printhead so as to flow along the suction slit.

2. A profile control device for a pneumatic direct-write printhead, the profile control device comprising: a first mounting hole extending through the first surface;

2. 2. The profile control device for a pneumatic direct-write printhead according to claim 1, wherein the suction slit is disposed coaxially with the second mounting opening.

3. 3. The profile control device for a pneumatic direct-write printhead according to claim 1, wherein a temperature control assembly is provided on the inner surface of the mounting hole to control the surface temperature of the direct-write printhead.

4. 4. The profile control device for a pneumatic direct-write printhead of claim 3, wherein the temperature control assembly comprises a temperature adjustment member and a temperature sensor for measuring a surface temperature of the pneumatic direct-write printhead.

5. A pneumatic direct-write printing stylus, characterized in that it comprises a profile control device according to any one of claims 1 to 4.

6. 6. The pneumatic direct-write print stylus according to claim 5, comprising: a head holder; and a direct-write print head provided on the head holder, wherein a droplet ejection port is provided at an end of the direct-write print head away from the head holder, and the cross-sectional area of ​​the direct-write print head decreases continuously along the ink flow direction of the droplet ejection port.

7. A direct writing device, characterized in that it comprises a pneumatic direct writing stylus according to claim 5 or 6.

8. 8. The direct-write device of claim 7, further comprising an elevator assembly for moving the pneumatic direct-write stylus up and down.

9. A method for using a direct writing device, comprising: during an acceleration / deceleration phase of direct writing, lifting the direct writing print head, opening a suction member, and sucking ink that comes into contact with the liquid guide port along the liquid guide port and suction slit in sequence so that ink on a surface of the direct writing print head does not come into contact with a printing substrate; and during an acceleration / deceleration phase of direct writing, closing the supply air pressure, opening the suction member, and sucking ink that comes into contact with the liquid guide port along the liquid guide port and suction slit in sequence.

10. A step S1 in which a monitoring probe of the temperature sensor collects temperature data of the direct-write printhead surface, and then uploads the temperature data to a controller via a communication module of the temperature sensor; and Step S2, in which the controller analyzes the temperature data and adjusts the temperature of the direct-write printhead surface by instructing a temperature adjustment member to increase or decrease the temperature based on the analysis result.

10. The method of claim 9, further comprising:

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