A deflection electrode-based arrayed electrohydrodynamic jet device and jetting method

Abstract

The application discloses an arrayed electrohydrodynamic jet printing device based on deflection electrodes and a jet printing method, and belongs to the technical field of inkjet printing. The jet printing device comprises an electrohydrodynamic jet head, a high-voltage power supply and a control module. The electrohydrodynamic jet head comprises an ink cartridge, a jet orifice plate, a nozzle, a deflection electrode and an insulating support. The ink cartridge is used for storing ink. The jet orifice plate is a flat plate with a through hole and is arranged at the bottom of the ink cartridge and is used for guiding the ink to flow into the nozzle. The insulating support is fixedly installed on the ink cartridge or the jet orifice plate and comprises a side wall and an extension part. A plurality of deflection electrodes are arranged on the side wall and correspond to the plurality of nozzles one by one. The extension part forms an ink droplet collecting box and is used for collecting the ink droplets deflected under the action of the deflection electrodes. The high-voltage power supply is used for generating the working voltage of the electrohydrodynamic jet head and the deflection voltage on the deflection electrodes. The control module is used for controlling the voltage signal output by the high-voltage power supply. The application can indirectly realize the independent control jetting of each nozzle and has higher stability.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of inkjet printing technology, and more particularly relates to an arrayed electrohydrodynamic printing device based on deflection electrodes and a printing method. BACKGROUND

[0002] Printing technology is a direct manufacturing technology without contact and template, which can realize digital flexible printing of solution at room temperature, normal pressure and non-clean environment, and can be mass manufactured in large area, and is one of effective ways to realize printed electronic manufacturing. In recent years, using printing technology to prepare printed electronic functional components has become a popular research field. Traditional inkjet printing can be divided into continuous ink-jetting (CIJ) and drop-on-demand (DOD) according to the generation mode of droplets.

[0003] As the latest printing technology, electrohydrodynamic printing has the following unique advantages compared with traditional inkjet printing: high resolution, which can reach micrometer or even nanometer level; wide viscosity range (1-10000 mPa·s), which is suitable for various functional materials; printing feature size is smaller than nozzle size, which can use larger size nozzle to realize higher printing resolution and reduce the manufacturing difficulty of nozzle; and nozzle is not easy to block, because the fluid flowability is enhanced under the action of electric field. Therefore, electrohydrodynamic printing process has wide application prospect in printed electronic manufacturing, such as electrojet printing, electrospinning and electrospray, which can be used to prepare electrodes, interconnection layers and film layers of printed electronic devices.

[0004] Arrayed electrohydrodynamic printing head is the key to realize industrialization of electrohydrodynamic printing. However, most of the experimental devices using nozzle array are difficult to realize independent controllable jetting and automatic printing, and can only simply parallel print patterns, which is difficult to further improve the ability of the system to print complex patterns. Patent CN201410289239.5 proposes a method for realizing independent controllable printing of the nozzle, but an external extraction electrode needs to be added below the nozzle, the ink liquid is easy to deviate to the extraction electrode, which causes damage to the nozzle, and the structure is complex and difficult to manufacture. Patent CN201510299992.7 proposes a micro electro-spray chip device and a manufacturing method, but the spray chip cannot realize independent regulation and control of the printing state of each nozzle. Patent CN202111078207.7 proposes an independent controllable printing electrohydrodynamic printing head, but also increases the complexity of the nozzle structure. SUMMARY

[0005] In view of the defects of the prior art and the demand for improvement, the present application provides an arrayed electrohydrodynamic jet printing device based on deflection electrodes and a jet printing method, which adds deflection electrodes on the side of the nozzle to control the movement track of the charged jet, so that the charged jet can smoothly drop to the surface of the substrate at the position where the ink droplet is needed; at the position where the ink droplet is not needed, the charged jet is deflected by the deflection electric field and falls into the ink droplet collection box, thereby indirectly realizing independent control of the nozzle.

[0006] To achieve the above-mentioned purpose, in a first aspect, the present application provides an arrayed electrohydrodynamic jet printing device based on deflection electrodes, comprising an electrohydrodynamic jet head, a high-voltage power supply and a control module.

[0007] The electrohydrodynamic jet head comprises an ink cartridge, a jet orifice plate, a nozzle, a deflection electrode and an insulating support; wherein the ink cartridge is used for storing ink; the jet orifice plate is a flat plate with through holes and is arranged at the bottom of the ink cartridge, the through holes are used for guiding the ink to flow into the nozzle; the insulating support is fixedly installed on the ink cartridge or the jet orifice plate and comprises a side wall and an extension part; a plurality of deflection electrodes are arranged on the side wall and correspond to a plurality of nozzles one by one, and the extension part forms an ink droplet collection box for collecting the ink droplets deflected under the action of the deflection electrode.

[0008] The high-voltage power supply is used for generating the working voltage of the electrohydrodynamic jet head and the deflection voltage on the deflection electrode.

[0009] The control module is used for controlling the voltage signal output by the high-voltage power supply.

[0010] Further, an insulating layer is arranged on the surface of the deflection electrode to prevent conduction between different deflection electrodes through the ink; the surface of the insulating layer is subjected to hydrophilic treatment to prevent the deflected ink droplets from splashing when entering the ink droplet collection box.

[0011] Further, the nozzle is in a boss structure, and the surface of the boss is subjected to insulation and hydrophobic treatment to prevent the liquid at the end of the nozzle from spreading during jet printing.

[0012] Further, the bottom of the ink droplet collection box is grounded to timely discharge the charges carried by the collected ink droplets.

[0013] Further, the accommodation groove in the ink droplet collection box is connected with the recovery pool, and the ink droplets recovered by the ink droplet collection box flow into the recovery pool by gravity.

[0014] To achieve the above-mentioned purpose, in a second aspect, the present application provides an arrayed electrohydrodynamic jet head independent jetting control method realized by using the arrayed electrohydrodynamic jet printing device based on deflection electrodes in the first aspect, which comprises the following steps:

[0015] The control module receives printing instructions and converts them into corresponding logical control signals output to the high-voltage power supply;

[0016] The high-voltage power supply applies working voltage to all the nozzles, so that the ink is sprayed in the form of charged jets;

[0017] The high-voltage power supply applies deflection voltage to the deflection electrodes corresponding to the nozzles of the charged jets that need to be deflected during the falling process, so that the charged jets are deflected into the ink droplet collection box, and the remaining charged jets fall vertically on the substrate.

[0018] Further, the ink droplets collected in the ink droplet collection box are filtered to remove impurities, then enter the recovery tank for dilution treatment to compensate for the solvent evaporated during the movement, and finally return to the ink cartridge through the pump pressure to realize recycling.

[0019] Overall, the above technical solutions conceived by the present application can achieve the following beneficial effects:

[0020] Compared with the existing method of placing a metal ring under the nozzle to control the droplet drop, the present application indirectly realizes independent control of each nozzle by deflecting the charged jets at the position of the ink droplet into the ink droplet collection box through the action of the deflection electrode. Thus, the present application has higher stability, and the deflection electrode is placed on the side compared to the metal ring placed under the nozzle, so the possibility of electrode contamination by ink droplets is greatly reduced. At the same time, compared with traditional electrofluidic printing equipment, the structure and control method of the nozzle are simpler. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 The structure schematic diagram of the arrayed electrofluidic printing device based on the deflection electrode provided by the embodiment of the present application;

[0022] Figure 2 The two-dimensional structure schematic diagram of the two different working modes of the electrofluidic printing head provided by the embodiment of the present application; (a) is the case where the charged jets fall vertically on the substrate, and (b) is the case where the charged jets are deflected into the ink droplet collection box. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application is further described in detail below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and do not limit the present application. In addition, the technical features involved in each embodiment of the present application described below can be combined with each other as long as they do not conflict with each other.

[0024] In the present application, the terms "first", "second", and the like (if present) in the present application and the accompanying drawings are used to distinguish similar objects, and do not necessarily describe a specific order or sequence.

[0025] The present application provides an arrayed electrospray device based on deflection electrodes, as shown in the accompanying drawings, comprising an electrospray head, a high-voltage power supply, and a control module. Figure 1 The electrospray head, the high-voltage power supply, and the control module are connected in series.

[0026] (1) The electrospray head comprises an ink cartridge, a jet orifice plate, a nozzle, a deflection electrode, and an insulating support array.

[0027] 1) The ink cartridge comprises an ink inlet, an ink outlet, and mounting holes; the ink inlet and the ink outlet are arranged at the upper end of the ink cartridge, the ink inlet is used for filling ink, and the ink outlet is used for discharging excess ink and air bubbles; the mounting holes are arranged on both sides of the ink cartridge and are used to mount and fix the position of the jet head.

[0028] 2) The jet orifice plate is a flat plate with through holes and is arranged at the bottom of the ink cartridge.

[0029] As a further optimization, the jet orifice plate can be processed on a flat plate of silicon or glass using laser ablation, lithography, sandblasting, etc. to obtain through holes for guiding the flow of ink into the nozzle.

[0030] 3) The nozzle is arranged at the bottom of the jet orifice plate and corresponds one-to-one to the through holes of the jet orifice plate. The ink flows from the ink cartridge through the through holes of the jet orifice plate into the nozzle and is finally sprayed from the tip of the nozzle.

[0031] As a further optimization, the nozzle is a convex structure, and the convex surface is treated with insulation and hydrophobicity. Silicon or glass materials can be used to process the nozzle, and then an insulating and hydrophobic layer is deposited, or a hydrophobic material can be directly used to process the convex structure of the nozzle, which facilitates the smooth ejection of ink droplets from the nozzle.

[0032] The diameter of the nozzle can vary in the range of 1-1000 microns, and the nozzle spacing can vary in the range of 1-1000 microns.

[0033] 4) The deflection electrode is used to control the deflection of the charged jet at a specific position. The deflection electrode is biased by a single electrode below the nozzle on one side, so that the ink droplets at the corresponding position are deflected by force.

[0034] As a further optimization, the deflection electrodes should be arranged in an array, with the number of deflection electrodes equal to the number of nozzles, and the arrangement position should correspond one-to-one to the arrayed nozzles in space. In addition, an insulating layer is arranged on the surface of the deflection electrode to prevent conduction between different deflection electrodes through the ink. The surface of the insulating layer is treated with hydrophilicity to prevent the deflected ink droplets from splashing when entering the ink droplet collection box, and to facilitate the entry of the ink droplets into the collection groove along the surface of the ink droplet collection box.

[0035] ​​The preparation method of the deflection electrode. First, the side wall can be selected from a glass substrate, which has good insulation and simple material acquisition characteristics, then the physical vapor deposition (PVD) method is selected to sputter the conductive electrode on the side wall, and the lead can be led out from the back of the glass substrate through the glass through hole (TGV), which can greatly reduce the influence on the front nozzle array control.

[0036] The deflection voltage of the deflection electrode. In the case of high voltage of the jet, the voltage of the deflection electrode has two requirements, one is the high voltage state, which should ensure that the deflection electrode has no effect on the charged jet, so that the ink droplet falls vertically on the substrate, as shown in Figure 2 (a); the other is the low voltage state, which should ensure that the ink droplet can be deflected and enter the ink droplet collection box, as shown in Figure 2 (b). At the same time, in order to reduce the influence of the deflection electrode on the original electrofluidic jet array, the control frequency of the deflection electrode signal should be consistent with the frequency and duty cycle of the opening voltage of the nozzle, and there is a certain lag in the opening and closing of the deflection electrode compared with the opening voltage of the nozzle, so that the deflection electrode is only opened after the ink droplet is ejected from the nozzle, and is in the off state at other times, so as to reduce the influence of the deflection electrode on the meniscus at the nozzle.

[0037] 5) The insulating support is fixedly installed on the ink cartridge or the jet orifice plate, including the side wall and the extension part. A plurality of deflection electrodes are arranged on the side wall and correspond to a plurality of nozzles one by one; the extension part forms an ink droplet collection box for collecting the ink droplets deflected under the action of the deflection electrode.

[0038] As a further preferred, the bottom of the ink droplet collection box, i.e. the channel where the ink droplets are collected in the ink droplet collection box, should be grounded through a lead wire, so as to timely discharge the charges carried by the collected ink droplets.

[0039] As a further preferred, the accommodation groove in the ink droplet collection box is connected with the corresponding recovery pool, and the ink droplets recovered through the ink droplet collection box flow into the recovery pool by gravity. The collected ink droplets will first pass through a filter to filter out impurities before entering the recovery pool, and then the mixed solution is diluted accordingly after being detected by various sensors (such as viscosity sensors or concentration sensors) in the recovery pool, so as to compensate for the evaporation of the solvent in the movement process. The treated solvent can be returned to the ink cartridge by pump pressure to realize recycling.

[0040] (2) A high-voltage power supply is used to generate the working voltage of the electrofluidic jet and the deflection voltage on the deflection electrode.

[0041] As a further preferred, the high-voltage power supply can be specifically combined with a signal generator and a signal amplifier to output, and the parameters can be manually adjusted. The output voltage signal is used to control the solution to be ejected at the nozzle, and to control the deflection electric field to make the specific ink droplet deflect.

[0042] (3) The control module is used for controlling the voltage signal output by the high-voltage power supply, so as to digitally control the switching state of the nozzle.

[0043] Specifically, the control module is composed of an upper computer and a digital master control module.

[0044] The upper computer is an interface for human-computer interaction, such as a personal computer PC, which can mainly convert the required printed pattern into printing data and send the printing data to the digital master control module, and can control the output parameters of the high-voltage power supply through software.

[0045] The digital master control module is a single-chip microcomputer. It is mainly responsible for receiving, processing, caching, outputting and timing logic control of the printing data. After receiving the required printing data, the control module converts it into the logic control signal required for the deflection electrode action, and then outputs it to the high-voltage power supply according to the given timing.

[0046] The application also provides an arrayed electrofluidic jet independent jetting control method realized by using the arrayed electrofluidic jet device based on the deflection electrode as described above, which comprises the following steps:

[0047] The control module receives the printing instructions and converts them into corresponding logic control signals output to the high-voltage power supply;

[0048] The high-voltage power supply applies working voltage to all the nozzles, so that the electric field force on the meniscus of the ink drops at the nozzles is greater than the surface tension, so that the ink liquid is sprayed in the form of charged jet, at this time all the nozzles are in the jetting state;

[0049] The high-voltage power supply applies deflection voltage to the deflection electrodes corresponding to the nozzles of the charged jet which needs to be deflected during the falling process, so that the part of the charged jet is deflected into the ink drop collecting box, and the remaining charged jet falls vertically on the substrate.

[0050] Specifically, the graphic printing process of the whole device is mainly as follows: first, the personal computer PC analyzes and processes the graphics to be printed, the analyzed graphic data is converted into a series of instructions for controlling whether the deflection electrodes corresponding to each nozzle of the electrofluidic jet are actuated, then the printing instructions are transmitted to the digital master control module, the digital master control module converts the printing instructions into the logic control signal required for the deflection electrode action, and finally the digital master control module outputs the logic control signal to the high-voltage power supply to realize the control of the deflection electrode, and completes the whole pattern printing process.

[0051] Those skilled in the art can easily understand that the above description is only a preferred embodiment of the application and is not intended to limit the application, and any modification, equivalent replacement and improvement made within the spirit and principle of the application shall be included in the protection scope of the application.

Claims

1. An arrayed electrofluid inkjet printing device based on deflection electrodes, characterized in that, Includes an electrohydrodynamic nozzle, a high-voltage power supply, and a control module; The electro-hydraulic nozzle includes an ink cartridge, an orifice plate, a nozzle, deflection electrodes, and an insulating support. The ink cartridge stores ink. The orifice plate is a flat plate with through holes and is located at the bottom of the ink cartridge; the through holes guide the ink into the nozzle. The insulating support is fixedly mounted on the ink cartridge or the orifice plate and includes a side wall and an extension. Multiple deflection electrodes are disposed on the side wall and correspond one-to-one with multiple nozzles. The extension forms an ink droplet collection box for collecting ink droplets deflected by the deflection electrodes. The bottom of the ink droplet collection box is grounded to promptly discharge the charge from the collected ink droplets. The deflection electrodes control the trajectory of the charged jet. Each deflection electrode is biased to one side below the nozzle, causing the ink droplets at the corresponding positions to be deflected by force. Specifically, the deflection electrode deflects the charged jet at the desired position. The electro-jet can smoothly drip onto the substrate surface; without needing a specific location for the ink droplets, the charged jet is deflected by the deflecting electric field and falls into the ink droplet collection box, indirectly achieving independent control of the nozzle. The voltage of the deflecting electrode has two requirements: one is a high-voltage state, which should ensure that the deflecting electrode does not affect the charged jet, allowing the ink droplets to fall vertically onto the substrate; the other is a low-voltage state, which should ensure that the ink droplets can be deflected and enter the ink droplet collection box. At the same time, in order to reduce the impact of the deflecting electrode on the original electro-hydraulic inkjet array, the control frequency of the deflecting electrode signal should be controlled to be consistent with the frequency and duty cycle of the nozzle's opening voltage, and there should be a certain lag between the opening and closing of the deflecting electrode and the opening voltage of the nozzle, so that the deflecting electrode is only turned on after ink droplets are ejected at the nozzle, and is in a closed state at other times, thereby reducing the impact of the deflecting electrode on the meniscus at the nozzle. The high-voltage power supply is used to generate the working voltage of the electro-hydraulic nozzle and the deflection voltage on the deflection electrode. The control module is used to control the voltage signal output by the high-voltage power supply.

2. The arrayed electrofluid inkjet printing device based on deflection electrodes according to claim 1, characterized in that, An insulating layer is provided on the surface of the deflection electrode to prevent different deflection electrodes from conducting through ink; the surface of the insulating layer is hydrophilic to prevent deflected ink droplets from splashing when entering the ink droplet collection box.

3. The arrayed electrofluid inkjet printing device based on deflection electrodes according to claim 1, characterized in that, The nozzle has a boss structure, and the surface of the boss is insulated and hydrophobic to prevent liquid from spreading at the tip of the nozzle during printing.

4. The arrayed electrofluid inkjet printing device based on deflection electrodes according to claim 1, characterized in that, The receiving tank in the ink droplet collection box is connected to the recycling pool, and the ink droplets collected by the ink droplet collection box flow to the recycling pool by gravity.

5. A method for independent jetting control of an arrayed electro-hydraulic printhead using an arrayed electro-hydraulic inkjet printing device based on deflection electrodes as described in any one of claims 1 to 4, characterized in that, Includes the following steps: The control module receives the printing command and converts it into a corresponding logic control signal, which is then output to the high-voltage power supply. The high-voltage power supply applies a working voltage to all nozzles, causing the ink to be ejected in the form of an electrified jet. The high-voltage power supply applies a deflection voltage to the deflection electrode corresponding to the nozzle of all charged jets that need to be deflected during the falling process, causing that part of the charged jet to be deflected and enter the ink droplet collection box, while the remaining charged jets fall vertically onto the substrate.

6. The independent jet control method for arrayed electro-hydraulic nozzles according to claim 5, characterized in that, The ink droplets collected in the ink droplet collection box are filtered to remove impurities and then enter the recycling tank. They are then diluted in the recycling tank to compensate for the solvent that evaporates during the process. Finally, they are pumped back into the ink cartridge for reuse.

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