Multi-mode array jet device and jet printing method

Abstract

The invention belongs to the technical field of ink-jet printing, and particularly relates to a multi-mode array jet device and a jet printing method.The device comprises a multi-mode printing head, a high-voltage power source and a control module; the printing head comprises a main body pressure chamber, an arrayed convex nozzle and an induction electrode corresponding to the arrayed convex nozzle; each convex nozzle is arranged on a corresponding spray hole of the main body pressure chamber; the induction electrode is arranged on the surface of a spraying hole plate, used for bearing the convex type nozzles, of the main body pressure cavity, is attached to the corresponding one or more convex type nozzles in a surrounding mode and is used for providing an induction electric field so as to assist piezoelectric driving to achieve ink spraying; and the control module is used for controlling voltage input of driving voltage of each vibrating plate in the multi-mode printing head so as to independently control each nozzle and concurrently control on-off of voltage of all electrodes according to the viscosity of printing ink, so that piezoelectric driving and switching of a piezoelectric and electrofluid joint driving printing mode are realized. The problem that high-viscosity ink cannot be printed through piezoelectric driving can be solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of inkjet printing, and more specifically, relates to a multi-mode arrayed jetting device and a jetting printing method. Background Art

[0002] Inkjet printing is a non-contact, template-free direct manufacturing technology that can achieve digital flexible printing of solutions at room temperature, pressure, and non-clean environments. It can be mass-produced over large areas and is one of the effective ways to achieve printed electronic manufacturing. In recent years, the use of inkjet printing technology to prepare printed electronic functional components has become a hot research field.

[0003] In traditional inkjet printing, inkjet printing can be divided into piezoelectric and thermal bubble in principle. Compared with the two, piezoelectric inkjet printing does not require the ink to be heated, and does not require high stability of the ink, but the viscosity range of the printing ink is lower than that of thermal bubble; secondly, compared with thermal bubble inkjet printing technology, piezoelectric reduces the damage to the print head caused by high temperature and extends the working life of the print head; finally, piezoelectric inkjet printing realizes ink ejection by applying electric pulses to the vibration plate, so the ink has a fast response speed and high precision. In view of these characteristics, piezoelectric inkjet printing has been widely used in the industrial field.

[0004] However, piezoelectric inkjet printing is limited by the viscosity of the ink. When the viscosity of the ink is too high, the vibration plate cannot provide sufficient driving force to squeeze out the ink, and the resolution of piezoelectric inkjet printing is low. Summary of the invention

[0005] In view of the defects and improvement needs of the prior art, the present invention provides a multi-mode arrayed jetting device and a jet printing method, which aims to solve the problem that piezoelectric drive cannot print high-viscosity ink.

[0006] To achieve the above object, according to one aspect of the present invention, a multi-mode arrayed jetting device is provided, comprising: a multi-mode print head, a high voltage power supply, and a control module;

[0007] The print head comprises a main body pressure chamber, an arrayed convex nozzle and a corresponding induction electrode; each convex nozzle is arranged on a corresponding nozzle hole of the main body pressure chamber for ejecting ink; the induction electrode is arranged on a nozzle hole plate surface of the main body pressure chamber for carrying the convex nozzle and is attached around a corresponding convex nozzle or multiple convex nozzles, for providing an induced electric field to assist piezoelectric drive to eject ink;

[0008] The high voltage power supply is used to power the induction electrode to provide an induced electric field;

[0009] The control module is used to control the voltage input of each vibration plate driving voltage in the multimodal print head, so as to achieve independent control of each convex nozzle; and to control the opening and closing of all induced electrode voltages in parallel according to the viscosity of the printing ink to achieve the switching of the printing mode, and the printing mode includes a piezoelectric drive printing mode and a printing mode in which piezoelectric drive and electrofluid drive act together.

[0010] Furthermore, the induction electrode is in a ring shape, a racetrack shape or a rectangle shape, and the induction electrodes are symmetrically distributed around the convex nozzle.

[0011] Furthermore, the material of the convex nozzle is SU-8 glue.

[0012] Furthermore, the control module controls the switching of all the induced electrode voltages in parallel according to the viscosity of the printing ink in a specific manner:

[0013] When the ink is low-viscosity ink, all induced electrode voltages are controlled to be turned off, and the ink is ejected only under piezoelectric drive; when the ink is low-viscosity ink and the required printing resolution is high or the ink is high-viscosity ink, all induced electrode voltages are controlled to be turned on, and a jet is formed under the joint action of piezoelectric drive and electrofluid drive.

[0014] Further, the main body pressure chamber includes: an ink supply hole, a pressure chamber, a flow limiting structure, a vibration plate, and a nozzle plate;

[0015] The ink supply hole is used to supply ink to the pressure chamber; the pressure chamber is used to temporarily store ink, and is also the area where pressure is generated after the vibration plate vibrates; the flow limiting structure is located at the entrance of the pressure chamber, and is used to prevent the ink from flowing back when the vibration plate squeezes the ink in the chamber; the vibration plate serves as the main driving component to provide power for the ink ejection; the orifice plate serves as the connecting part between the pressure chamber and the convex nozzle, and plays the role of supporting the nozzle.

[0016] Furthermore, the material of the pressure chamber is SU-8 glue.

[0017] The present invention also provides a multi-mode jet printing method, which is implemented by using a multi-mode arrayed jetting device as described above, specifically:

[0018] A printing instruction is input into the control module of the multi-mode arrayed injection device. The control module selects different printing modes according to the printing instruction, and outputs corresponding high-frequency control signals and control signals of the induced electrode voltage to the vibration plate in the multi-modal print head and the high-voltage power supply connected to the induced electrode, respectively, to realize piezoelectric driven printing or printing with the combined action of piezoelectric drive and electrofluid drive.

[0019] In general, the above technical solutions conceived by the present invention can achieve the following beneficial effects:

[0020] The present invention adds an induction electrode and a convex nozzle in the main pressure chamber. When the ink cannot be ejected smoothly due to excessive viscosity, the induced electric field is turned on to allow the ink to be ejected smoothly under the combined action of the extrusion force of the vibration plate in the main pressure chamber and the electric field force of the induction electrode, thereby meeting the printing requirements of inks with different viscosities; at the same time, when printing low-viscosity inks, it can also be selected to print under the combined action of piezoelectric drive and electrofluid drive to achieve higher-resolution printing. In this way, the injection device proposed by the present invention is compatible with the mature process and structure of piezoelectric inkjet printing, and at the same time meets the requirements of compatibility with inks of different viscosities and different printing resolutions through electrofluid drive. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A bottom view schematically shows a multi-mode arrayed print head provided by an embodiment of the present invention.

[0022] Figure 2 A schematic top view of another multi-mode arrayed print head provided by an embodiment of the present invention.

[0023] Figure 3 An exploded view of a multi-mode arrayed print head provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0025] Embodiment 1

[0026] A multi-mode arrayed jetting device comprises: a multi-mode print head, a high voltage power supply, and a control module;

[0027] like Figure 1 As shown, the print head includes a main body pressure chamber, an arrayed convex nozzle and its corresponding induction electrode; each convex nozzle is arranged on a corresponding nozzle hole of the main body pressure chamber for ejecting ink; the induction electrode is arranged on the surface of the nozzle plate for carrying the convex nozzle of the main body pressure chamber and is attached around the corresponding convex nozzle or multiple convex nozzles, and is used to provide an induced electric field to assist the piezoelectric drive to realize the ejection of ink;

[0028] The high voltage power supply is used to energize the induction electrode to provide an induced electric field;

[0029] The control module is used to control the voltage input of each vibration plate driving voltage in the multimodal print head, so as to achieve independent control of each convex nozzle; and to control the opening and closing of all induced electrode voltages in parallel according to the viscosity of the printing ink to achieve the switching of printing modes. The printing modes include piezoelectric drive printing mode and piezoelectric drive and electrofluid drive combined printing mode.

[0030] This embodiment takes into account that electrohydrodynamic printing technology (Electrohydrodynamic Printing) is the latest printing technology and has the following unique advantages compared to traditional inkjet printing: high resolution, which can reach the micron or even nanometer level; a wide viscosity range (1 to 10000 mPa·s), which is suitable for a variety of functional materials; the printing feature size is smaller than the nozzle size, and a larger nozzle size can be used to achieve a higher printing resolution, which reduces the difficulty of nozzle manufacturing; the nozzle is not easy to be blocked, and the fluidity of the fluid is enhanced under the action of the electric field. It can be seen that the electrohydrodynamic printing process also has broad application prospects in printed electronics manufacturing. This embodiment proposes a multi-mode array injection device combining piezoelectric drive and electrohydrodynamic drive, which meets the requirements of being compatible with inks of different viscosities and using different printing resolutions, and can solve the problem that the piezoelectric drive to be solved by the present invention cannot print high-viscosity inks.

[0031] Compared with the traditional piezoelectric inkjet printing which is limited by the viscosity of the printing ink, this embodiment draws on the control method of electrofluidic printing, and by adding an induction electrode and a convex nozzle, when the ink cannot be smoothly ejected due to excessive viscosity, the induced electric field is turned on to allow the ink to be smoothly ejected under the combined action of the extrusion force of the vibration plate and the electric field force of the induction electrode, thereby meeting the printing requirements of inks of different viscosities; at the same time, when printing low-viscosity inks, it can also be selected to print under the combined action of piezoelectric drive and electrofluid drive to achieve higher-resolution printing. In this way, this embodiment is compatible with the mature process and structure of piezoelectric inkjet printing, and at the same time meets the requirements of compatibility with inks of different viscosities and different printing resolutions through electrofluid drive.

[0032] Preferably, an induction electrode is provided on the orifice plate, and the shape of the electrode is selected to be ring-shaped, runway-shaped or rectangular, wherein the induction electrode should be symmetrically distributed around the nozzle, the outer surface of the electrode needs to be coated with an insulating layer, the electrode needs to correspond one-to-one with the nozzle or correspond to different regions, and all electrodes are disconnected in parallel to realize the switching of the printing mode. In addition, the nozzle is a boss structure, and the surface of the boss can be insulated and hydrophobic to prevent the liquid from spreading at the end of the nozzle during injection. The nozzle adopts a convex nozzle, which is convenient for the formation of the meniscus of the ink and plays a role in concentrating the electric field. It should be noted that the induction electrode is attached to a corresponding convex nozzle or multiple convex nozzles, that is, the induction electrode needs to correspond one-to-one with the nozzle or correspond to different regions.

[0033] As a preferred embodiment, the control module controls the switching of all the induced electrode voltages in parallel according to the viscosity of the printing ink in the following specific manner:

[0034] When the ink is low-viscosity ink, all induced electrode voltages are controlled to be turned off, and the ink is ejected only under piezoelectric drive; when the ink is low-viscosity ink and the required printing resolution is high or the ink is high-viscosity ink, all induced electrode voltages are controlled to be turned on, and a jet is formed under the joint action of piezoelectric drive and electrofluid drive.

[0035] That is, according to the different viscosities of the ink, the device adopts different driving methods for printing, so the multimodal print head can be divided into three working modes: first, low-viscosity ink is directly ejected by piezoelectric drive. At this time, the induced electrode voltage is turned off, and the ink is ejected only under piezoelectric drive; secondly, low-viscosity ink forms a jet under the joint action of piezoelectric drive and electrofluid drive. At this time, compared with the piezoelectric drive alone, the printing resolution is higher; finally, high-viscosity ink is ejected under the joint action of piezoelectric drive and electrofluid drive. This mode solves the problem that piezoelectric drive cannot print high-viscosity ink.

[0036] It should be noted that low-viscosity ink is ink that can be normally ejected and printed by the ejection device under piezoelectric drive, whereas high-viscosity ink is ink that is difficult to eject and print by the ejection device under piezoelectric drive.

[0037] In one embodiment, the main pressure chamber includes: an ink supply hole, a pressure chamber, a flow limiting structure, a vibration plate, and a nozzle plate; the ink supply hole is used to supply ink to the pressure chamber; the pressure chamber is used to temporarily store ink, and is also the area where pressure is generated after the vibration plate vibrates; the flow limiting structure is located at the entrance of the pressure chamber, and is used to prevent the ink from flowing back when the vibration plate squeezes the ink in the chamber; the vibration plate serves as the main driving component to provide power for the ejection of ink; the nozzle plate serves as the connecting part between the pressure chamber and the convex nozzle, and plays the role of supporting the nozzle.

[0038] like Figure 3 As shown, the ink supply hole is connected to the external ink cartridge to supply ink to the print head; the pressure chamber is particularly important in the entire multimodal print head structure. As an important part connecting the vibration plate, the nozzle plate, and the ink supply port, when the multimodal print head is working, the ink is squeezed by the vibration plate in the chamber and flows to the nozzle.

[0039] Considering that most inks are corrosive, and the pressure chamber will inevitably be subjected to the pressure exerted by the ink and the heat transferred by the vibration plate when the multimodal print head is working, the corrosion resistance, thermal stability and mechanical properties of the material should be considered when selecting the chamber material. In traditional piezoelectric inkjet print heads, silicon materials are usually selected as chamber materials, among which SU-8 glue can be used as the preferred pressure chamber material because it has good mechanical properties and is easy to process to obtain a material with a high aspect ratio.

[0040] The flow-limiting structure usually refers to a high flow resistance structure set at the entrance of the pressure chamber. When the vibration plate squeezes the ink in the pressure chamber, the ink tends to flow to the end with smaller flow resistance, and the flow-limiting structure at the entrance of the chamber effectively prevents the backflow of the ink, making it easier for the ink to flow to the nozzle position. The flow-limiting structure increases the flow resistance by reducing the cross-sectional area of ​​the flow channel. This can be achieved by setting a step structure in the depth direction and reducing the flow channel area in the plane direction.

[0041] The vibration plate is one of the power sources of the multi-modal print head. When a driving voltage is applied, the vibration plate squeezes the ink in the chamber through vibration, forcing the ink to be ejected from the nozzle.

[0042] Specifically, the vibration plate is a multi-layer composite structure composed of a lower electrode layer, a piezoelectric layer (PZT material), an upper electrode layer, an elastic layer, a protective layer, etc. The upper and lower electrode layers and the piezoelectric layer together constitute the main body of the vibration plate, i.e., the piezoelectric element; the elastic layer is used to support the piezoelectric element to prevent the piezoelectric element from being damaged by force; the protective layer mainly serves to isolate the external environment to ensure that the piezoelectric element can work stably for a long time.

[0043] Preferably, PZT is selected as the piezoelectric material for driving, Pt is selected as the upper and lower electrode materials, and Ti is selected as the adhesion layer of the electrode; silicon dioxide with better mechanical properties and simpler preparation process is selected as the elastic layer material; polyimide with high deposition rate, better moisture resistance and better insulation is selected as the protective layer material.

[0044] The orifice plate is a flat plate with through holes. The induction electrode is arranged on the orifice plate and can be designed into various shapes such as circular ring, racetrack and rectangle according to requirements.

[0045] The orifice plate can be obtained by processing through holes on a flat plate such as silicon or glass using processes such as laser ablation, photolithography, and sandblasting. The through holes are used to guide the ink to flow into the nozzle; the material of the induction electrode is selected as gold, and the induction electrode is patterned on the orifice plate through photolithography and etching processes.

[0046] The convex nozzle is set at the bottom of the orifice plate and corresponds to the through hole of the orifice plate one by one. The ink flows from the ink cartridge through the through hole of the orifice plate, enters the nozzle, and finally sprays out from the tip of the nozzle. The nozzle can be processed with silicon or glass materials, and then an insulating and hydrophobic layer is deposited, or a hydrophobic material such as SU-8 glue is directly used to process the boss structure of the nozzle, so that the ink can be sprayed smoothly from the nozzle.

[0047] The nozzle diameter can be varied in the range of 5 to 100 μm, and the nozzle spacing can be varied in the range of 300 to 1000 μm.

[0048] The power supply system is used to provide the high-voltage power supply required for the induction electrode to work. The high-voltage power supply required by the induction electrode can be specifically output by a combination of a signal generator and a signal amplifier, and its control signal is provided by the control module.

[0049] The control module is used to control the high-frequency voltage signal output by the multi-modal print head control board and loaded onto both ends of the vibration plate to digitally control the switch state of the nozzle and the switch of the high-voltage power supply applied to the induction electrode to achieve the switching of the print head printing mode. Specifically, the control module consists of a host computer and a digital main control module. The host computer is a human-computer interaction interface such as a personal computer PC, which mainly converts the pattern to be printed into print data and sends it to the digital main control module.

[0050] The digital main control module is the control board for the vibration plate drive signal and the induction electrode drive signal. It is mainly responsible for the reception, processing, caching, output and timing logic control of the printing data. After receiving the required printing data, the control module will output the high-frequency control signal required for the vibration plate to the upper and lower electrodes of the vibration plate according to the given timing, and transmit the control signal of the induction electrode to the power supply system.

[0051] In general, this embodiment provides a printing device with a wider range of ink viscosity adaptability and higher resolution accuracy. According to the different ink viscosities, the device uses different driving methods for printing, so the multi-modal print head can be divided into three working modes: first, low-viscosity ink is directly ejected by piezoelectric drive, at this time the induced electrode voltage is turned off, and the ink is ejected only under piezoelectric drive; second, low-viscosity ink forms a jet under the joint action of piezoelectric drive and electrofluid drive, at this time, compared with the single piezoelectric drive, the printing resolution is higher; finally, high-viscosity ink is ejected under the joint action of piezoelectric drive and electrofluid drive, and this mode solves the problem that piezoelectric drive cannot print high-viscosity ink.

[0052] Embodiment 2

[0053] A multi-mode jet printing method is implemented using a multi-mode arrayed jet device as described above, specifically:

[0054] A printing instruction is input into the control module of the multi-mode arrayed injection device. The control module selects different printing modes according to the printing instruction, and outputs corresponding high-frequency control signals and control signals of the induced electrode voltage to the vibration plate in the multi-modal print head and the high-voltage power supply connected to the induced electrode, respectively, to realize piezoelectric driven printing or printing with the combined action of piezoelectric drive and electrofluid drive.

[0055] Specifically, the control module receives a printing instruction, selects different printing modes according to the printing instruction, and outputs the corresponding high-frequency control signal and the control signal of the induced electrode voltage to the corresponding vibration plate and high-voltage power supply; the vibration plate begins to controllably squeeze the ink in the chamber under the drive of the high-frequency control signal, and the control module controls the opening and closing of the high-voltage power supply acting on the induced electrode according to the printing instruction, and selects the printing mode according to the printing instruction, so that the above two driving modes act alone or together to achieve different printing requirements.

[0056] In fact, this embodiment is a control method for independent ejection of a multi-modal print head using an arrayed ejection device that combines piezoelectric drive and electrofluid drive as described above. In specific implementation, the following steps can be followed:

[0057] First, the user sets the required printing pattern information and ink viscosity through the host computer. The host computer selects an appropriate printing mode based on the information input by the user and the viscosity of the ink, and then sends the required printing pattern information to the control module.

[0058] The control module receives the printing instruction from the host computer, and selectively outputs the corresponding high-frequency control signal to the vibration plate, and transmits the control signal of the induction electrode to the power supply system;

[0059] According to the ink viscosity provided by the user, when the ink viscosity is lower than the reference value, the ink can be sprayed smoothly only by squeezing the vibration plate. At this time, the control module controls the induced electrode voltage to be turned off; the ink can also be selected to be printed with high resolution under the joint action of piezoelectric drive and electrofluid drive. At this time, the control module controls the induced electrode voltage to be turned on in parallel, selects the nozzle through the piezoelectric drive, and realizes high-resolution printing of low-viscosity ink with the assistance of electrofluid drive.

[0060] According to the ink viscosity provided by the user, when the ink viscosity is higher than the reference value, it is assumed that the ink cannot be ejected smoothly only by squeezing the vibration plate. The ink flows to the nozzle under the squeezing of the vibration plate and converges at the end of the nozzle but cannot be broken and ejected. At this time, the control module controls the induced electrode voltage to be turned on in parallel, and the ink at the end of the nozzle is smoothly broken and ejected under the action of the induced electric field.

[0061] Specifically, the graphic printing process of the entire device is mainly as follows: first, the personal computer PC will parse and process the graphics to be printed, and the parsed graphic data will be converted into a series of instructions for controlling whether each vibration plate in the multimodal print head is in motion, and then these printing instructions will be transmitted to the digital main control module, which will convert the printing instructions into the high-frequency control signal required by the vibration plate to achieve independent control of each vibration plate in the print head; at the same time, the control module will also compare the viscosity of the printing ink with the reference value, so as to control the opening and closing of the induced electrode and realize the switching of different printing modes, and finally complete the printing process of the entire pattern under the joint action of the vibration plate extrusion and the induced electric field.

[0062] The relevant technical solution is the same as that in Embodiment 1 and will not be described in detail here.

[0063] In general, compared with traditional piezoelectric inkjet printing, the present invention combines piezoelectric drive and electrofluid drive to invent a new injection device, which is not only compatible with the mature process of piezoelectric inkjet printing, but also has the advantages of electrofluidic printing ink with a wide viscosity range and high printing resolution, effectively solving the problems of traditional piezoelectric printing inability to print high viscosity ink and low printing resolution.

[0064] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A multi-mode array injection device, characterized in that: include: Multi-modal print head, high voltage power supply, and control module; The multi-modal print head comprises a main body pressure chamber, an arrayed convex nozzle and a corresponding induction electrode; each convex nozzle is arranged on a corresponding nozzle hole of the main body pressure chamber for ejecting ink; the induction electrode is arranged on a nozzle hole plate surface of the main body pressure chamber for carrying the convex nozzle and is attached around a corresponding convex nozzle or multiple convex nozzles, for providing an induced electric field to assist piezoelectric drive to eject ink; The high voltage power supply is used to power the induction electrode to provide an induced electric field; The control module is used to control the voltage input of the driving voltage of each vibration plate in the multi-modal print head, so as to achieve independent control of each convex nozzle; And according to the viscosity of the printing ink, all the induced electrode voltages are controlled to be turned on and off in parallel to realize the switching of the printing mode, wherein the printing mode includes a piezoelectric drive printing mode and a printing mode in which piezoelectric drive and electrofluid drive act together.

2. A multi-mode arrayed spraying device according to claim 1, characterized in that: The induction electrodes are in the shape of a ring, a racetrack or a rectangle, and are symmetrically distributed around the convex nozzle.

3. A multi-mode arrayed spraying device according to claim 1, characterized in that: The material of the convex nozzle is SU-8 glue.

4. A multi-mode arrayed spraying device according to claim 1, characterized in that: The control module controls the switching of all the induced electrode voltages in parallel according to the viscosity of the printing ink in a specific manner: When the ink is low-viscosity ink, all induced electrode voltages are controlled to be turned off, and the ink is ejected only under piezoelectric drive; when the ink is low-viscosity ink and the required printing resolution is high or the ink is high-viscosity ink, all induced electrode voltages are controlled to be turned on, and a jet is formed under the joint action of piezoelectric drive and electrofluid drive.

5. A multi-mode arrayed spraying device according to claim 1, characterized in that: The main body pressure chamber comprises: an ink supply hole, a pressure chamber, a flow limiting structure, a vibration plate, and a nozzle plate; The ink supply hole is used to supply ink to the pressure chamber; the pressure chamber is used to temporarily store ink, and is also the area where pressure is generated after the vibration plate vibrates; the flow limiting structure is located at the entrance of the pressure chamber, and is used to prevent the ink from flowing back when the vibration plate squeezes the ink in the chamber; the vibration plate serves as the main driving component to provide power for the ink ejection; the orifice plate serves as the connecting part between the pressure chamber and the convex nozzle, and plays the role of supporting the nozzle.

6. A multi-mode arrayed spraying device according to claim 5, characterized in that: The material of the pressure chamber is SU-8 glue.

7. A multi-mode jet printing method, characterized in that: The method is implemented by using a multi-mode arrayed injection device as claimed in any one of claims 1 to 6, specifically: A printing instruction is input into the control module of the multi-mode arrayed injection device. The control module selects different printing modes according to the printing instruction, and outputs corresponding high-frequency control signals and control signals of the induced electrode voltage to the vibration plate in the multi-modal print head and the high-voltage power supply connected to the induced electrode, respectively, to realize piezoelectric driven printing or printing with the combined action of piezoelectric drive and electrofluid drive.

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