High-quality printing method based on low-viscosity ink
By using low-viscosity ink and substrate pretreatment, combined with liquid bridge technology, the printing instability and accuracy problems during the low-viscosity ink printing process are solved, high-quality printing effect is achieved, and energy consumption is reduced.
Patent Information
- Application Number
- CN202510596663.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-09
- Publication Date
- 2025-08-01
AI Technical Summary
During the low-viscosity ink printing process, there are problems such as difficulty in regulating printing process parameters, unstable printing process and poor graphical edge morphology, resulting in limited use of electric fluid inkjet printing in actual manufacturing.
A printing method with low viscosity ink (solid content less than or equal to 50%, viscosity range from 1 millipal sec to 100 millipal sec, surface tension less than or equal to 100 millipal sec per meter) is used to form a liquid bridge in combination with the pretreatment of the printed substrate and the control of the distance between the ink ejection module and the substrate is less than the nozzle diameter. The anti-interference ability of the liquid bridge is used to apply appropriate injection voltage and air pressure for printing.
Improve printing accuracy, efficiency and stability, achieve a balance between printing accuracy, efficiency and stability, improve the quality of printing patterns, and reduce energy consumption.
Smart Images
Figure CN120396529A_ABST
Abstract
Description
Technical Field
[0001] This application relates to, but is not limited to, the field of fluid jet printing technology, and particularly relates to a high-quality printing method based on low-viscosity ink. Background Art
[0002] Electrohydrodynamic inkjet printing technology is very suitable for the manufacturing requirements of increasingly customized high-precision electronic devices due to its advantages of high precision, non-contact, and maskless patterning. Low-viscosity inks have received extensive attention in the field of electrohydrodynamic inkjet printing technology due to their good fluidity and wide applicability. However, the inkjet printing process of low-viscosity inks usually faces challenges such as difficult regulation of printing process parameters, unstable printing process, and poor edge morphology of patterning, which limit the use of electrohydrodynamic inkjet printing in actual manufacturing processes. Therefore, the embodiments of this application provide a high-quality printing method suitable for low-viscosity inks, which can effectively improve the printing accuracy, printing efficiency, and printing stability of electrohydrodynamic printing. Summary of the Invention
[0003] The following is an overview of the subject matter described in detail herein. This overview is not intended to limit the scope of protection of the claims.
[0004] The embodiments of this application provide a high-quality printing method based on low-viscosity ink, which can effectively improve the printing accuracy, printing efficiency, and printing stability.
[0005] To achieve the above object, a first aspect of the embodiments of the present application provides a high-quality printing method based on low-viscosity ink, including: loading printing ink into an inkjet module, where the solid content of the printing ink is less than or equal to 50%, the viscosity range of the printing ink is 1 millipascal-second to 100 millipascal-seconds, and the surface tension of the printing ink is less than or equal to 100 millinewtons per meter; pre-treating the surface of the printing substrate, where the surface energy of the pre-treated printing substrate is greater than or equal to the surface energy of the printing ink; controlling the inkjet module for jetting the printing ink to move to the starting point of the printing path, where the jetting distance between the jetting end of the inkjet module and the printing substrate is less than or equal to half of the nozzle diameter; where the jetting distance is 0.03 millimeters to 0.15 millimeters, and the nozzle diameter is 0.06 millimeters to 0.3 millimeters; while controlling the inkjet module to move along the printing path, controlling the inkjet module to apply a preset jetting air pressure to the printing ink and apply a jetting voltage to the inkjet module, so that the inkjet module prints the printing ink on the surface of the printing substrate until the inkjet module reaches the end point of the printing path, obtaining a printed functional layer pattern, where the jetting voltage is 100 volts to 1000 volts, the jetting voltage is greater than or equal to the opening voltage of the printing ink, and the sum of the electric field force, the back pressure, and the gravity of the printing ink is greater than or equal to the surface tension of the printing ink. When the inkjet module moves, a liquid bridge is formed between the inkjet module and the printing substrate for the printing ink.
[0006] In one embodiment, before controlling the inkjet module for jetting the printing ink to move to the starting point of the printing path, it further includes: obtaining a printing pattern, determining the nodes on the printing pattern and the starting point of the printing pattern; designing a printing path according to the nodes of the printing pattern, where the designed printing path is an Euler graph or a combination of Euler graphs; obtaining a printed target printing pattern by combining multiple printing paths.
[0007] In some embodiments, when the printing pattern is a solid filling pattern, the printing process needs to satisfy R ≤ W / 2, and when the printing pattern is a linear pattern, the printing needs to satisfy R > W / 2, where R is the printing path spacing, W is the printing path line width, and W / 2 is the printing path fillet radius; where the printing path spacing is 5 micrometers to 400 micrometers, and the printing path line width is 30 micrometers to 600 micrometers.
[0008] In one embodiment, the printing method further includes: curing the printed functional layer pattern, where the curing treatment includes one or a combination of natural curing, heat annealing, and ultraviolet light annealing.
[0009] In one embodiment, the pretreatment of the surface of the printed substrate includes: pretreating the surface of the printed substrate by gas plasma, wherein the gas plasma includes one or a combination of argon plasma, nitrogen plasma, oxygen plasma, carbon tetrafluoride plasma, and octafluorocyclobutane plasma.
[0010] In one embodiment, the pretreatment of the surface of the printed substrate further includes: spin-coating a polymer fluid on the surface of the printed substrate, wherein the polymer fluid includes one or a combination of polyvinyl alcohol, polyvinylpyrrolidone, polyacrylic acid, polyacrylamide, polyimide, thermoplastic polyurethane elastomer, and polytetrafluoroethylene.
[0011] In one embodiment, the pretreatment of the surface of the printed substrate further includes: irradiating the printed substrate with ultraviolet light.
[0012] In one embodiment, the surface flatness of the printed substrate is less than 10% of the nozzle diameter.
[0013] In one embodiment, the printing method further includes: when the inkjet module reaches the end of the printing path, controlling the inkjet module to move vertically upward to break the liquid bridge and obtain a printed functional layer pattern.
[0014] In one embodiment, the moving speed of the inkjet module along the printing path needs to satisfy v = kσ / η so that the transverse shear force on the liquid bridge is always less than the surface tension of the printing ink; where v represents the moving speed, the moving speed is 0.5 millimeters per second to 6 millimeters per second, k is a preset constant, σ represents the surface tension of the printing ink, and η represents the viscosity of the printing ink.
[0015] In one embodiment, half of the nozzle diameter is less than or equal to the width of the printed functional layer pattern, the width of the printed functional layer pattern is less than or equal to twice the distance between the nozzles, and the error of the edge flatness of the printed functional layer pattern is less than or equal to 5%.
[0016] The embodiments of the present application at least include the following beneficial effects:
[0017] 1) Before injecting the printing ink onto the printed substrate, by pretreating the printed substrate with different processes, impurities on the surface of the printed substrate can be removed, keeping the surface of the printed substrate clean; and without the need to adjust the ink composition, it can be matched with the substrate, enabling the ink to form pinning on the substrate without destroying the printing morphology, and at the same time improving the adhesion of the printed pattern on the substrate.
[0018] 2) During the process of ejecting printing ink onto a printing substrate, a liquid bridge is formed by controlling the distance between the ink ejection module and the printing substrate to be less than the diameter of the ink ejection module. The anti-interference ability of the liquid bridge is utilized to prevent the printing ink from splashing, eliminating the possibility of generating satellite dots and greatly improving the printing stability and the quality of printed patterns. At the same time, since the distance between the ink ejection module and the printing substrate is small, a strong enough electric field can be formed with a very small applied voltage to eject the ink, which is conducive to reducing energy consumption and achieving green manufacturing.
[0019] 3) This method improves the balance of printing accuracy, printing efficiency, and printing stability, effectively achieving the balance among printing accuracy, printing efficiency, and printing stability, thereby being able to improve the quality of the printed pattern of the printing functional layer.
[0020] Other features and advantages of the present application will be described in the subsequent specification, and part of them will be obvious from the specification or understood by implementing the present application. The objectives and other advantages of the present application can be realized and obtained through the structures specifically pointed out in the specification, claims, and drawings. Description of the Drawings
[0021] The drawings are used to provide a further understanding of the technical solutions of the present application, and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the technical solutions of the present application and do not constitute a limitation to the technical solutions of the present application.
[0022] Figure 1 It is an optional flowchart of a high-quality printing method based on low-viscosity ink provided by an embodiment of the present application;
[0023] Figure 2 It is an optional flowchart of determining a printing path provided by an embodiment of the present application;
[0024] Figure 3 It is a schematic diagram for explaining the printing path of an Euler pattern provided by an embodiment of the present application;
[0025] Figure 4 It is a schematic diagram for explaining the printing path of a non-Euler graph provided by an embodiment of the present application;
[0026] Figure 5 It is an optional specific flowchart of preprocessing a printing substrate provided by an embodiment of the present application;
[0027] Figure 6 It is an optional flowchart of controlling the movement of an ink ejection module provided by an embodiment of the present application;
[0028] Figure 7 It is a printed physical diagram of a silver wire printed functional layer pattern provided by an embodiment of the present application;
[0029] Figure 8 Cross-sectional schematic diagram of the silver wire printing functional layer pattern provided by the embodiment of the present application;
[0030] Figure 9 Conductivity schematic diagram of the silver wire printing functional layer pattern provided by the embodiment of the present application;
[0031] Figure 10 Printed physical diagram of the carbon fiber printing functional layer pattern provided by the embodiment of the present application;
[0032] Figure 11 Cross-sectional schematic diagram of the carbon fiber printing functional layer pattern provided by the embodiment of the present application;
[0033] Figure 12 Printed physical diagram of the printing line of the high-quality printing method provided by the embodiment of the present application;
[0034] Figure 13 Printed physical diagram of the printing line of the on-demand printing method provided by the embodiment of the present application;
[0035] Figure 14 Printed physical diagram of the printing pattern of the high-quality printing method provided by the embodiment of the present application;
[0036] Figure 15 Printed physical diagram of the printing pattern of the on-demand printing method provided by the embodiment of the present application;
[0037] Figure 16 An optional system block diagram of the fluid inkjet printer provided by the embodiment of the present application;
[0038] Figure 17 An optional structural schematic diagram of the fluid inkjet printer provided by the embodiment of the present application;
[0039] Figure 18 An optional process schematic diagram of the fluid inkjet printer provided by the embodiment of the present application. Detailed Description of the Invention
[0040] The embodiments of the present invention will be described in detail below. Examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary only for explaining the present invention and should not be construed as limiting the present invention.
[0041] In the description of the present invention, it should be understood that, regarding the orientation description, for example, the orientations or positional relationships indicated by up, down, front, back, left, right, etc. are based on the orientations or positional relationships shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present invention.
[0042] In the description of the present invention, the meaning of several is more than one, and the meaning of multiple is more than two. Understandings such as greater than, less than, exceeding, etc. do not include the recited number, and understandings such as above, below, within, etc. include the recited number. If there is a description of first and second, it is only for the purpose of distinguishing technical features and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features or implicitly indicating the sequence relationship of the indicated technical features.
[0043] In the description of the present invention, unless otherwise clearly defined, terms such as set, install, connect, etc. should be understood in a broad sense, and those skilled in the art can reasonably determine the specific meanings of the above terms in the present invention in combination with the specific content of the technical solution.
[0044] In the description of the present invention, the descriptions with reference to terms such as "one embodiment", "some embodiments", "schematic embodiments", "examples", "specific examples", or "some examples", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic descriptions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.
[0045] In the related art, in the prior art, the sprayed solution is mostly a polymer solution with a high mass fraction, which has high material costs, high viscosity, and is not resistant to high temperatures. When using the traditional inkjet process for printing, the nozzles are prone to clogging, and patterning manufacturing cannot be completed.
[0046] Based on this, the embodiments of the present application provide a high-quality printing method based on low-viscosity ink, which can effectively avoid clogging of the printing ink in the ink jet module and improve the smoothness of ink jet printing.
[0047] The high-quality printing method based on low-viscosity ink provided by the embodiments of the present application is specifically described through the following embodiments. First, the high-quality printing method based on low-viscosity ink in the embodiments of the present application is described.
[0048] The following further elaborates on the embodiments of the present application with reference to the drawings.
[0049] As Figure 1As shown Figure 1 FIG. Figure 1 is an optional process schematic diagram of a high-quality printing method based on low-viscosity ink provided by an embodiment of the present application. The high-quality printing method based on low-viscosity ink includes but is not limited to the following steps S110 to S140:
[0050] Step S110: Load printing ink into an inkjet module, where the solid content of the printing ink is less than or equal to 50%, the viscosity range of the printing ink is 1 mPa·s to 100 mPa·s, and the surface tension of the printing ink is less than or equal to 100 mN / m;
[0051] Step S120: Pretreat the surface of the printing substrate, where the surface energy of the pretreated printing substrate is greater than or equal to the surface energy of the printing ink;
[0052] Step S130: Control the inkjet module for jetting printing ink to move to the starting point of the printing path, where the jetting distance between the jetting end of the inkjet module and the printing substrate is less than or equal to half of the nozzle diameter, where the jetting distance is 0.03 mm to 0.15 mm and the nozzle diameter is 0.06 mm to 0.3 mm;
[0053] Step S140: While controlling the inkjet module to move along the printing path, control the inkjet module to apply a preset jetting air pressure to the printing ink and apply a jetting voltage to the inkjet module, so that the inkjet module prints the printing ink on the surface of the printing substrate until the inkjet module reaches the end point of the printing path, obtaining a printed functional layer pattern, where the jetting voltage is 100 V to 1000 V, the jetting voltage is greater than or equal to the opening voltage of the printing ink, and the sum of the electric field force, back pressure, and gravity acting on the printing ink is greater than or equal to the surface tension of the printing ink. When the inkjet module moves, a liquid bridge is formed between the inkjet module and the printing substrate.
[0054] First, before jetting the printing ink onto the printing substrate, by pretreating the printing substrate with different processes, impurities on the surface of the printing substrate can be removed, keeping the surface of the printing substrate clean; and without adjusting the ink components, it can be matched with the substrate, enabling the ink to form pinning on the substrate without damaging the printing morphology, and at the same time improving the adhesion of the printed pattern on the substrate.
[0055] Secondly, during the process of jetting printing ink onto a printing substrate, a liquid bridge is formed by controlling the distance between the ink jetting module and the printing substrate to be less than the diameter of the ink jetting module. The anti-interference ability of the liquid bridge is utilized to prevent the printing ink from splashing, eliminating the possibility of generating satellite dots, and greatly improving the printing stability and the quality of the printed pattern. At the same time, since the distance between the ink jetting module and the printing substrate is small, a strong enough electric field can be formed with a very small applied voltage to jet the ink, which is beneficial to reducing energy consumption and realizing green manufacturing.
[0056] In summary, this method improves the balance of printing accuracy, printing efficiency, and printing stability, effectively achieving the balance among printing accuracy, printing efficiency, and printing stability, thereby being able to improve the quality of the pattern of the printing functional layer.
[0057] In a specific embodiment, the ink jetting module includes an ink chamber, a nozzle, a gas compressor, and a transformer. The ink chamber is used to store ink. The gas compressor and the transformer are respectively arranged above the ink chamber, and the nozzle is arranged below the ink chamber. The gas compressor is used to inject gas into the ink chamber to apply a downward jet air pressure to the printing ink. The transformer is used to apply an electric field with a range from between the ink jetting module and the printing substrate and with the electric field line direction vertically downward. When starting to print, the ink jetting module moves to directly above the starting point of the printing path, the printing ink is supplied to the jet end of the ink jetting module, the printing ink forms an initial hanging drop at the nozzle, the jet voltage applied by the transformer to the printing ink is greater than the opening voltage of the printing ink, and a jet air pressure is applied above the printing ink so that the electric force, gas pressure, and the gravity of the printing ink itself satisfy that the sum of the electric force, gas pressure, and gravity is equal to the surface tension of the printing ink, enabling the printing ink to form a meniscus in a balanced state at the end of the nozzle.
[0058] Then, control the jetting distance between the ink jetting module and the printing substrate to be less than half of the nozzle diameter. At this time, the meniscus at the nozzle contacts the substrate surface so that a liquid bridge is formed between the ink jetting module and the printing substrate.
[0059] Then, drive the ink jetting module at a certain speed and keep the jetting distance between the ink jetting module and the printing substrate unchanged so that the tangential surface tension and frictional force received by the liquid bridge part are in dynamic balance, and the electric force, gas pressure, and gravity received are in dynamic balance with the normal surface tension until the liquid bridge breaks when the ink jetting module reaches the end of the printing path and is lifted or the printing ink in the ink jetting module is exhausted, thereby enabling the width and height of the ink line formed on the printing path to be uniform. It can be understood that the printing substrate can be a flexible film or a rigid sheet, which will not be limited here.
[0060] In addition, referring to Figure 2 as shown,Figure 1 Before step S130 in
[0061] Step S210, obtain a printed pattern, and determine the nodes on the printed pattern and the starting point of the printed pattern;
[0062] Step S220, design a printing path according to the nodes of the printed pattern, and the printing path is an Euler graph or a combination of Euler graphs;
[0063] Step S230, obtain a printed target pattern by combining multiple printing paths.
[0064] In addition, referring to Figure 3 and Figure 4 As shown, the Euler pattern is directly printed with the starting point determined by the Euler path, and the non-Euler pattern can be obtained by multiple Euler paths or a combination of Euler paths.
[0065] In a specific embodiment, when a part of the printed pattern is a straight line segment, take the two endpoints of the straight line segment as nodes. When a part of the printed pattern is an arc segment, collect nodes on the arc segment according to a preset sampling rate.
[0066] Specifically, according to the printed pattern and the nodes on the printed pattern, determine at least one printed Euler graph. The combined shape of all printed Euler graphs is the same as the printed pattern. Then, obtain the injection voltage, injection air pressure, and nozzle diameter, determine the height and width of the ink line, calculate the cross-sectional area of the ink line according to the height and width, determine the longest printing length per single printing according to the cross-sectional area and the volume of the printing ink in the ink injection module, truncate and combine the printed Euler graph according to the longest printing length to obtain at least one target Euler graph, and determine the starting point and ending point of each target Euler graph, so as to determine the printing path.
[0067] It can be understood that by calculating the cross-sectional area of the ink line and calculating the longest printing length per single printing according to the volume of the printing ink in the ink injection module, when the length of a single printing is greater than the longest printing length, the ink injection module idles and cannot eject ink. When the length of a single printing is less than the longest printing length, there is residual printing ink in the ink injection module after completing a single printing. Therefore, by truncating and combining the printed Euler graph according to the longest printing length, for a target Euler graph obtained by cutting one of the printed Euler graphs, if the path length of the printed Euler graph is greater than the longest printing length, then at most one target Euler graph has a path length less than the longest printing length, and the path lengths of the remaining target Euler graphs are all equal to the longest printing length, so as to reduce the number of interruptions and path changes of the ink injection module during the moving printing process, ensure the coherence of the ink line, and improve the quality of the printed functional layer pattern.
[0068] In addition, for different printed patterns, the processing requirements for the printing process in this application also vary. Specifically, when the printed pattern is a solid-filled pattern, the printing process needs to satisfy R ≤ W / 2; when the printed pattern is a linear pattern, the printing needs to satisfy R > W / 2, where R is the printing path spacing, W is the printing path line width, and W / 2 is the printing path fillet radius.
[0069] Among them, the printing path spacing is from 5 microns to 400 microns, and the printing path line width is from 30 microns to 600 microns.
[0070] In one embodiment, the printing method proposed in this application further includes:
[0071] Performing a curing treatment on the printed functional layer pattern, where the curing treatment includes one or more combinations of natural curing, heat annealing, and ultraviolet light annealing.
[0072] It can be understood that by performing a curing treatment on the printed functional layer pattern, the solvent or dispersion medium in the printing ink can be completely volatilized, the mechanical strength of the ink circuit on the printed functional layer pattern can be improved, and the conductive particles or molecules in the printing ink can be promoted to form a stable conductive network.
[0073] In one embodiment, Figure 1 Step S120 in
[0074] Pre-treating the surface of the printing substrate with gas plasma, where the gas plasma includes one or more combinations of argon plasma, nitrogen plasma, oxygen plasma, carbon tetrafluoride plasma, and octafluorocyclobutane plasma.
[0075] It can be understood that by pre-treating the surface of the printing substrate with the gas plasma of inert gases, such as argon plasma and nitrogen plasma, the gas plasma of inert gases can remove the contaminants on the surface of the printing substrate, reduce the influence of the contaminants on the conductive performance of the printing ink, and in addition, increase the surface roughness of the substrate and enhance the adhesion of the ink to the substrate surface; or, by pre-treating the surface of the printing substrate with the gas plasma of active gases, such as oxygen plasma, the active gas plasma treatment can introduce polar functional groups on the surface of the printing substrate, increase the surface energy of the printing substrate, thereby improving the wettability and adhesion of the printing substrate to the printing ink, reducing the offset of the printing ink on the printing substrate, and enhancing the consistency between the ink circuit and the printed pattern.
[0076] In one embodiment, Figure 1 Step S120 in
[0077] Spin-coat the polymer fluid on the surface of the printed substrate, where the polymer fluid includes one or a combination of polyvinyl alcohol, polyvinylpyrrolidone, polyacrylic acid, polyacrylamide, polyimide, thermoplastic polyurethane elastomer, and polytetrafluoroethylene.
[0078] It can be understood that by covering the surface of the printed substrate with the polymer fluid, the surface energy of the surface of the printed substrate can be changed, which helps the printing ink to adhere to the surface of the printed substrate; and the polymer fluid can form a protective layer on the surface of the printed substrate to protect the printed substrate from wear.
[0079] In one embodiment, Figure 1 Step S120 in
[0080] Irradiate the printed substrate with ultraviolet light.
[0081] It can be understood that by irradiating the printed substrate with ultraviolet light, the organic contaminants on the surface of the printed substrate can be effectively removed, and the contact angle of the ink on the substrate can be reduced.
[0082] In one embodiment, the pretreatment of the surface of the printed substrate can be one or a combination of gas plasma treatment, polymer surface covering treatment, and ultraviolet irradiation treatment.
[0083] In one embodiment, as Figure 5 shown, Figure 1 Step S120 in
[0084] Step S310, pretreat the surface of the printed substrate with gas plasma, where the gas plasma includes one or a combination of argon plasma, nitrogen plasma, oxygen plasma, carbon tetrafluoride plasma, and octafluorocyclobutane plasma;
[0085] Step S320, spin-coat the polymer fluid on the surface of the printed substrate to form an insulating film on the surface of the printed substrate, where the polymer fluid includes one or a combination of polyvinyl alcohol, polyvinylpyrrolidone, polyacrylic acid, polyacrylamide, polyimide, thermoplastic polyurethane elastomer, and polytetrafluoroethylene;
[0086] Step S330, irradiate the printed substrate and the insulating film with ultraviolet light.
[0087] Specifically, in this embodiment, the printed circuit board is a rigid circuit board. As described above, the surface of the printed circuit board is pretreated by gas plasma to clean the surface of the printed circuit board. Then, the polymer fluid is evenly coated on the surface of the printed circuit board to form an insulating film on the surface of the printed circuit board. The polymer fluid is stably cured by irradiating the printed circuit board film with ultraviolet light, and the surface of the insulating film is cleaned. When the inkjet module moves directly above the printed circuit board, the printing ink is ejected onto the surface of the insulating film. When the printing ink is cured on the surface of the insulating film, a flexible printed functional layer pattern can be obtained.
[0088] In some embodiments, the surface flatness of the printed circuit board is less than 0.1 times the nozzle diameter.
[0089] It can be understood that by reducing the surface flatness of the printed circuit board, the brush substrate surface spreads evenly, improving the uniformity of the printed pattern. In addition, it can avoid the breakage of the liquid bridge caused by the unevenness of the substrate and damage the printed pattern.
[0090] Refer to Figure 6 As shown, in some embodiments, the printing method proposed in this application further includes but is not limited to the following step S410:
[0091] Step S410, when the inkjet module reaches the end of the printing path, control the inkjet module to move vertically upward to break the liquid bridge and obtain the printed functional layer pattern.
[0092] It can be understood that when the inkjet module reaches the end of the printing path, that is, when the printing process is about to end, when the inkjet module moves upward or the printed circuit board moves away from the inkjet module, the accumulation of ink at the end position is avoided, and the printing ink is also prevented from splashing to other positions on the printed circuit board, improving the printing quality of the printed functional layer pattern.
[0093] In one embodiment, the raw materials of the printing ink include toner, ethyl cellulose, dibasic acid ester, sodium alginate, and surfactant.
[0094] Specifically, the solid content of the printing ink is less than or equal to 50%, the viscosity range of the printing ink is 1 millipascal-second to 100 millipascal-seconds, and the surface tension of the printing ink is less than or equal to 100 millinewtons per meter.
[0095] When the inkjet module moves to the end of the printing path, the inkjet moves vertically upward by 0.3 mm to break the liquid bridge.
[0096] It can be understood that by restricting the solid content of the printing ink to a relatively low level, it helps to reduce the viscosity of the printing ink and form a stable liquid bridge; by restricting the surface tension of the printing ink to an appropriate level, it helps to form a stable liquid bridge, enables the printing ink to spread on the printing substrate, improves the electrical conductivity of the ink circuit, and at the same time helps the printing ink to solidify on the printing substrate.
[0097] It should be noted that the printing ink can also be nano-silver particle ink or other conductive inks, which are not restricted here.
[0098] In addition, in a specific embodiment, the moving speed of the inkjet module along the printing path needs to satisfy v = kσ / η, so that the lateral shear force on the liquid bridge is always less than the surface tension of the printing ink;
[0099] wherein, v represents the moving speed, the moving speed is from 0.5 millimeters per second to 6 millimeters per second, k is a preset constant, σ represents the surface tension of the printing ink, and η represents the viscosity of the printing ink.
[0100] It can be understood that by presetting the constant k, based on the surface tension and viscosity of the printing ink, controlling the moving speed of the inkjet module to satisfy v = kσ / η, so that during the movement of the inkjet module, the lateral shear stress received by the liquid bridge formed between the inkjet module and the printing substrate is always less than the surface tension of the printing ink, so that the liquid can always remain unbroken during the movement, and the quality of the printed functional layer pattern is improved.
[0101] In addition, in some embodiments of the present application, half of the nozzle diameter is less than or equal to the width of the printed functional layer pattern, the width of the printed functional layer pattern is less than or equal to twice the distance between the nozzles, and the error of the edge flatness of the printed functional layer pattern is less than or equal to 5%.
[0102] In addition, the present application also proposes a printed functional layer pattern film, which is obtained by printing by the printing method in the above embodiments.
[0103] It can be understood that since the printed functional layer pattern in this embodiment is made by the high-quality printing method based on low-viscosity ink in the above embodiments, therefore, the printed functional layer pattern in this embodiment has the beneficial effects brought by the high-quality printing method based on low-viscosity ink mentioned in the above specific embodiments.
[0104] In addition, referring to Figures 7 to 9As shown, in a specific embodiment, the printed substrate is a PCB substrate, the printing ink is nano silver particle ink DGP4LT15C, the ink viscosity is 15 millipascal seconds. Take 1 milliliter of the printing ink and add it into an ink nozzle of model 34G. The material of the ink nozzle is stainless steel, and the inner diameter of the ink nozzle is 60 microns. The glass substrate is subjected to oxygen plasma treatment for 10 minutes. Preferably, the printing height is set to 10 microns; the jet voltage is 200 volts DC; the supplied jet air pressure is atmospheric pressure; the moving speed of the printed substrate is 5 millimeters per second. Relatively, the moving speed of the ink nozzle relative to the printed substrate is 5 millimeters per second; the moving path is a line segment; the number of printing times is 1 time. After printing, preferably, first cure naturally for 2 hours, and then anneal at 100 degrees Celsius for 20 minutes to obtain a silver wire printed functional layer pattern. Use a profilometer to perform a topography test on the silver wire printed functional layer pattern. As can be seen from Figure 8 As can be seen, Figure 8 shows the cross-section of the silver wire printed functional layer pattern. The side in close contact with the x-axis corresponds to one end of the silver wire printed functional layer pattern in contact with the printed substrate. The y-axis direction represents the height of the silver wire printed functional layer pattern. The surface of the printed functional layer pattern obtained by the printing method proposed in this application is smooth and flat, and there is no accumulation of printing ink at both the printing start point and the printing end point. The printing topography of the printed functional layer pattern is excellent; as shown in Figure 9 As shown, use a four-probe resistance tester to perform electrical property tests on the four printed functional layer patterns in Figure 7 respectively. Figure 9 The abscissa in
[0105] represents the voltage applied across both ends of each printed functional layer pattern, and the ordinate represents the current flowing through each printed functional layer pattern. As can be seen, the conductivity of the four printed functional layer patterns is basically the same, which can illustrate that the four printed functional layer patterns are evenly distributed on the printed substrate. Figure 10 and Figure 11 shown, in a specific embodiment, the printed substrate is a flexible PI substrate. Grind the carbon fiber powder, ethyl cellulose, dibasic acid ester, sodium alginate and surfactant and mix them in a certain proportion to obtain the printing ink. The ink viscosity is 15 millipascal seconds. Take 1 milliliter of the printing ink and add it into an ink nozzle of model 34G. The material of the ink nozzle is stainless steel, and the inner diameter of the ink nozzle is 60 microns. The flexible PI substrate is subjected to UV light treatment for 10 minutes. Preferably, the printing height is set to 10 microns; the jet voltage is 400 volts AC; the supplied jet air pressure is 20 kPa; the moving speed of the printed substrate is 2 millimeters per second. Relatively, the moving speed of the ink nozzle relative to the printed substrate is 2 millimeters per second; the moving path is set to pass through a designed negative Poisson's ratio pattern; the number of printing times is 5 times. After printing, preferably, anneal at 60 degrees Celsius for 30 minutes to obtain a printed carbon fiber printed functional layer pattern. Refer to Figure 11As shown Figure 11 The cross-section of the carbon fiber printed functional layer pattern is shown. One side in close contact with the x-axis corresponds to one end where the carbon fiber printed functional layer pattern contacts the printed substrate. The y-axis direction represents the height of the carbon fiber printed functional layer pattern. The morphology of the printed silver wire profile is tested using a step profiler. The edge of the cross-section of the obtained carbon fiber printed functional layer pattern is regular, uniformly distributed, and the line height and line width have high consistency.
[0106] In addition, referring to Figure 12 and Figure 13 、 Figure 14 and Figure 15 As shown, in a specific embodiment, the line patterns and interdigital electrode patterns printed by the printing method of this patent and the traditional on-demand printing method are compared. The printed substrate is a glass substrate, the printing ink is nano silver particle ink DGP4LT15C, the ink viscosity is 15 millipascal seconds, 1 milliliter of printing ink is taken and added to a capillary glass nozzle with an inner diameter of 5 microns; the glass substrate is treated with oxygen plasma for 10 minutes. For the printing method of this patent, preferably, the printing height is set to 1 micron; the ejection voltage is 100 V DC; the supply ejection air pressure is atmospheric pressure; the moving speed of the printed substrate is 0.5 mm per second. Relatively, the moving speed of the ink nozzle relative to the printed substrate is 0.5 mm per second. For the on-demand printing method, the following are adopted: the printing height is set to 10 microns; the ejection voltage is 800 V pulsed voltage, the pulse width is 10 mm, and the frequency is 1 Hz; the supply ejection air pressure is atmospheric pressure; the moving speed of the printed substrate is 0.005 mm per second. Relatively, the moving speed of the ink nozzle relative to the printed substrate is 0.5 mm per second. The moving paths of the two printing methods are both line segments and the interdigital electrodes drawn by the design method of the belonging path; the number of printing times is 1 time. After printing, preferably, it is first naturally cured for 10 minutes and then annealed at 100 °C for 20 minutes to obtain the silver wire printed functional layer pattern. Referring to Figure 12 and Figure 13 As shown Figure 12 and Figure 13 respectively show the line patterns printed by the printing method of this patent and the traditional on-demand printing method. From the optical image of the printed pattern, it can be seen that the edge of the line pattern obtained by the printing method of this patent is smoother and has higher consistency. Referring to Figure 14 and Figure 15 As shown Figure 14 and Figure 15 respectively show the interdigital electrode patterns printed by the printing method of this patent and the traditional on-demand printing method. From the optical image of the printed pattern, it can be seen that the edge of the interdigital electrode pattern obtained by the printing method of this patent is regular, the line patterns are uniformly distributed, and the interdigital spacing is smaller, that is, a pattern with higher resolution can be obtained.
[0107] In addition, referring to Figures 16 to 18As shown in the figure, the present application also provides an electrohydrodynamic printer, which includes:
[0108] A base 100 for placing a printing substrate, and the base 100 is grounded;
[0109] A pretreatment module 200 for preprocessing the printing substrate;
[0110] An ink jetting module 300 is disposed directly above the base 100. The ink jetting module 300 stores printing ink, and the ink jetting module 300 is used to jet the printing ink onto the printing substrate;
[0111] A control module 400. The pretreatment module 200 and the ink jetting module 300 are respectively electrically connected to the control module 400. The control module 400 is used to execute the high-quality printing method based on low-viscosity ink in the above embodiments.
[0112] It can be understood that since the electrohydrodynamic printer in this embodiment is used to execute the above high-quality printing method based on low-viscosity ink, therefore, the electrohydrodynamic printer in this embodiment has the beneficial effects brought by the high-quality printing method based on low-viscosity ink mentioned in the above specific embodiments.
[0113] The embodiments described in the embodiments of the present application are for more clearly illustrating the technical solutions of the embodiments of the present application, and do not constitute a limitation to the technical solutions provided by the embodiments of the present application. Those skilled in the art know that with the evolution of technology and the emergence of new application scenarios, the technical solutions provided by the embodiments of the present application are equally applicable to similar technical problems.
[0114] Those skilled in the art can understand that Figures 1 to 6 the technical solutions shown in do not constitute a limitation to the embodiments of the present application, and may include more or fewer steps than those shown, or combine certain steps, or different steps.
[0115] The terms "first", "second", "third", "fourth", etc. (if any) in the specification of the present application and the above drawings are used to distinguish similar objects, and do not have to be used to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so that the embodiments of the present application described here can be implemented in an order other than those illustrated or described here. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units does not have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.
[0116] It should be understood that in this application, "at least one (item)" means one or more, and "a plurality" means two or more. "And / or" is used to describe the association relationship of associated objects, indicating that three relationships can exist. For example, "A and / or B" can mean: only A exists, only B exists, and both A and B exist simultaneously. Among them, A and B can be singular or plural. The character " / " generally indicates that the associated objects before and after are in an "or" relationship. "At least one (item) of the following" or its similar expression refers to any combination of these items, including any combination of single item (item) or plural items (items). For example, at least one (item) of a, b, or c can mean: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, c can be single or multiple.
[0117] The preferred embodiments of the embodiments of this application have been described above with reference to the accompanying drawings. However, this does not limit the scope of the rights of the embodiments of this application. Any modification, equivalent replacement, and improvement made by those skilled in the art without departing from the scope and essence of the embodiments of this application shall be within the scope of the rights of the embodiments of this application.
Claims
1. A high-quality printing method based on low-viscosity ink, characterized in that, Including: Loading printing ink into an inkjet module, wherein the solid content of the printing ink is less than or equal to 50%, the viscosity range of the printing ink is 1 millipascal-second to 100 millipascal-seconds, and the surface tension of the printing ink is less than or equal to 100 millinewtons per meter; Pre-treating the surface of a printing substrate, wherein the surface energy of the pre-treated printing substrate is greater than or equal to the surface energy of the printing ink; Controlling the inkjet module for jetting the printing ink to move to the starting point of a printing path, wherein the jetting distance between the jetting end of the inkjet module and the printing substrate is less than or equal to half of the nozzle diameter; Wherein the jetting distance is 0.03 millimeters to 0.15 millimeters, and the nozzle diameter is 0.06 millimeters to 0.3 millimeters; While controlling the inkjet module to move along the printing path, controlling the inkjet module to apply a preset jetting air pressure to the printing ink and applying a jetting voltage to the inkjet module, so that the inkjet module prints the printing ink on the surface of the printing substrate until the inkjet module reaches the end point of the printing path, obtaining a printed functional layer pattern, wherein the jetting voltage is 100 volts to 1000 volts, the jetting voltage is greater than or equal to the firing voltage of the printing ink, and the sum of the electric field force, the back pressure, and the gravity of the printing ink is greater than or equal to the surface tension of the printing ink. When the inkjet module moves, a liquid bridge is formed between the inkjet module and the printing substrate.
2. The printing method according to claim 1, characterized in that, Before controlling the inkjet module for jetting the printing ink to move to the starting point of the printing path, it further includes: Obtaining a printing pattern, and determining the nodes of the printing pattern and the starting point of the printing pattern; Designing a printing path according to the nodes of the printing pattern, and the printing path is an Euler graph or a combination of Euler graphs; Obtaining a printing target pattern by combining multiple printing paths.
3. The printing path according to claim 2, wherein, When the printing pattern is a solid filling pattern, the printing process needs to satisfy R≤W / 2. When the printing pattern is a linear pattern, the printing needs to satisfy R>W / 2, where R is the printing path spacing, W is the printing path line width, and W / 2 is the printing path fillet radius; Wherein the printing path spacing is 5 micrometers to 400 micrometers, and the printing path line width is 30 micrometers to 600 micrometers.
4. The printing method according to claim 1, characterized in that The printing method further includes: Performing a curing treatment on the printed functional layer pattern, wherein the curing treatment includes one or a combination of natural curing, heat annealing, and ultraviolet light annealing.
5. The printing method according to claim 1, characterized in that, The pre-treating the surface of the printing substrate includes: Pre-treating the surface of the printing substrate by gas plasma, wherein the gas plasma includes one or a combination of argon plasma, nitrogen plasma, oxygen plasma, carbon tetrafluoride plasma, and octafluorocyclobutane plasma.
6. The printing method according to claim 1, characterized in that, The pre-treating the surface of the printing substrate further includes: Spin-coat the polymer fluid on the surface of the printed substrate, where the polymer fluid includes one or more combinations of polyvinyl alcohol, polyvinylpyrrolidone, polyacrylic acid, polyacrylamide, polyimide, thermoplastic polyurethane elastomer, and polytetrafluoroethylene.
7. The printing method according to claim 1, wherein The pretreatment of the surface of the printed substrate further includes: Irradiate the printed substrate with ultraviolet light.
8. The printing method according to claim 1, wherein The surface flatness of the printed substrate is less than 10% of the nozzle diameter.
9. The printing method according to claim 1, wherein The printing method further includes: When the inkjet module reaches the end of the printing path, control the inkjet module to move vertically upward to break the liquid bridge and obtain the printed functional layer pattern.
10. The printing method according to claim 1, characterized in that, The moving speed of the inkjet module along the printing path needs to satisfy v = kσ / η so that the lateral shear force on the liquid bridge is always less than the surface tension of the printing ink; where v represents the moving speed, the moving speed is from 0.5 millimeters per second to 6 millimeters per second, k is a preset constant, σ represents the surface tension of the printing ink, and represents the viscosity of the printing ink.
11. The high-quality printing method based on low-viscosity ink according to claim 1, wherein Half of the nozzle diameter is less than or equal to the width of the printed functional layer pattern, the width of the printed functional layer pattern is less than or equal to twice the distance between the nozzles, and the error of the edge flatness of the printed functional layer pattern is less than or equal to 5%.