CN113211983B - Piezoelectric ink-jet system applied to printing ink drops and optimization method thereof - Google Patents

Abstract

The invention discloses a piezoelectric inkjet system applied to printing ink droplets, comprising a central control system, a piezoelectric inkjet subsystem and an ink droplet optimization system. Control system connection; piezoelectric inkjet subsystem includes piezoelectric drive module, piezoelectric print head and ink supply assembly, piezoelectric drive module is connected with central control system, piezoelectric print head includes multiple nozzles, piezoelectric print head and piezoelectric drive module The ink supply assembly is connected with the piezoelectric print head; the ink droplet optimization system includes a multi-channel heating device and a temperature control adjustment device. The multi-channel heating device is provided with a plurality of heating channels corresponding to the nozzles on the piezoelectric print head, and the temperature control adjustment device Used to adjust the temperature of each heating channel. Corresponding optimization methods are also provided. The main ink droplets and satellite droplets enter the multi-channel heating device together. After heating, the satellite droplets are completely volatilized, and the main ink droplets are further reduced, which overcomes the limitation of the size of the nozzle on ultra-high-precision printing.

Description

A Piezoelectric Inkjet System Applied to Printing Ink Droplets and Its Optimization Method

technical field

The invention relates to the field of printed electronics, and more particularly, to a piezoelectric inkjet system applied to printing ink droplets and an optimization method thereof.

Background technique

As a non-contact, non-pressure, and mask-free printing technology, inkjet printing technology can accurately spray very small droplets (with a volume of picoliters or femtoliters) at the desired position, and form a thin film after the solvent is evaporated, dried and cured. . Inkjet printing technology has the advantages of low cost, large area, green environmental protection, etc., making this technology gradually become a wet method to prepare microelectronic devices, such as electroluminescent OLED devices (especially organic full-color display), color filter in LCD. Optical sheets, organic thin film field effect transistors, LED packaging, and wearable electronic devices have received more and more attention from academia and industry.

However, there are many production process limitations in the field of ultra-high-precision printing, and technical difficulties have been restricting the development of inkjet printing to prepare high-quality films and ultra-precision display devices. For example, if the ultra-high-resolution display screen is produced by the technology of inkjet printing, it is necessary to use an inkjet head with a very small diameter. The price is expensive, and it is prone to failure during the working process, and there is still a big gap between the prepared screen and the evaporation technology; in addition, the process stability of inkjet printing is poor, and it is very easy to print during the printing process. The phenomenon of ink drop tailing occurs, resulting in messy satellite droplets around the main ink droplet finally deposited on the substrate, which seriously affects the display effect of the device. The traditional solution is to use high-quality special printing ink or appropriately change the temperature to reduce satellite droplets. However, these methods cannot completely eliminate the generation of satellite droplets, and the special ink is expensive, which greatly limits the research and development of multiple varieties of ink.

For the optimization and feedback adjustment of ink droplets in the process of inkjet printing, there are already some related technical solutions for this aspect in existing patents, such as early patents such as CN106808798B. However, further research shows that the technologies involved in the existing patents still have the following deficiencies: First, most of them perform unified adjustment of multi-nozzle nozzles or single adjustment of single-nozzle nozzles, not in the process of multi-nozzle nozzle spraying. All nozzles will generate satellite droplets, which can not be effectively controlled only by the same adjustment or single adjustment; second, most of them reduce the generation of satellite droplets by adjusting the external driving voltage or regulating the temperature of the ink, but the ejected The size of the main ink droplet is basically unaffected. The size of the main ink droplet is still restricted by the diameter of the nozzle, and the satellite droplet can only be reduced but not completely eliminated. At the same time, a small amount of satellite droplets will also cause material waste and environmental pollution. Correspondingly, there is an urgent need in the art to propose a more appropriate solution to meet the current increasing technological requirements.

SUMMARY OF THE INVENTION

The purpose of the present invention is to overcome the limitations on the preparation of ultra-precision printed display devices caused by the limitation that the nozzle size cannot be further reduced in the current inkjet printing technology, and the satellite ink droplets that always exist in the inkjet printing process lead to low final printing quality. A piezoelectric ink-jet system for printing ink droplets and an optimization method thereof are provided. The technical solution of the present invention is not limited by the size of the printing nozzle, and the main ink droplets ejected can be further reduced to meet the requirements of higher-precision printing and display; at the same time, the system and the optimization method designed by the present invention can ignore the falling process. The satellite ink droplets can be automatically eliminated without using special printing ink or adjusting the optimal ink temperature, and a small amount of solute particles in the satellite droplets can be recovered for secondary use, which greatly reduces the printing cost.

In order to achieve the foregoing purpose of the invention, the present invention provides a piezoelectric inkjet system applied to printing ink droplets, including a central control system, a piezoelectric inkjet subsystem and an ink droplet optimization system, a piezoelectric inkjet subsystem and an ink droplet optimization system The systems are respectively connected with the central control system;

The piezoelectric inkjet subsystem includes a piezoelectric drive module, a piezoelectric print head and an ink supply assembly. The piezoelectric drive module is connected to the central control system. The piezoelectric print head includes a plurality of nozzles. The piezoelectric print head is connected to the piezoelectric drive module and supplies ink. The component is connected with the piezoelectric nozzle;

The ink droplet optimization system includes a multi-channel heating device and a temperature control adjusting device. The multi-channel heating device is provided with a plurality of heating channels corresponding to the nozzles on the piezoelectric print head. The temperature of the channel is adjusted.

After the above technical solution is adopted, the main ink droplet and the trailing satellite droplet enter the multi-channel heating device in the ink droplet optimization system together, and after heating, the satellite droplet is completely volatilized, and the main ink droplet after passing through the multi-channel heating device is further reduced. Overcome the limitation of print head size for ultra-high-precision printing.

A further improvement to the solution of the present invention further includes an ink drop monitoring system, the ink drop monitoring system includes a camera for collecting images of the falling ink drop, and the camera is connected to the central control system.

A further improvement to the solution of the present invention, the ink drop monitoring system further includes a light source controller and a parallel detection light source, the light source controller is connected with the central control system, and the parallel detection light source is connected with the light source controller.

A further improvement of the solution of the present invention, the central control system includes a host computer, an image acquisition module, an image analysis module and a data processing module, the image acquisition module collects the falling image of the ink drop through a camera, and the image acquisition module is used to collect the image of the falling ink drop. The image analysis module is used to analyze whether there are still satellite droplets according to the image of the falling ink droplets, the data processing module is used to obtain the serial number of the nozzle that ejects the satellite droplets, and the host computer is used to send the temperature control adjustment command to the temperature control adjustment according to the serial number. device.

A further improvement to the solution of the present invention, the piezoelectric drive module in the piezoelectric inkjet subsystem includes a PCI waveform generating card and a voltage amplifier, the PCI waveform generating card is communicated with the central control system, and the voltage amplifier is connected with the PCI waveform generating card.

A further improvement to the solution of the present invention, the ink supply assembly includes a pneumatic pump and an ink storage container, the pneumatic pump and the ink storage container are connected by pipelines, and the ink storage container is communicated with the ink input end of the piezoelectric nozzle.

A further improvement to the solution of the present invention, each heating channel in the multi-channel heating device is provided with a heating element,

The temperature control and adjustment device includes a multi-channel relay, a single-chip microcomputer and a serial port conversion module. The output end of the single-chip microcomputer is connected with the multi-channel relay to control the on-off of each branch of the multi-channel relay, and the single-chip microcomputer is connected with the central control system through the serial port conversion module, wherein, Each heating element is respectively electrically connected with each branch in the multi-circuit relay. The temperature of the heating channel can be adjusted by the temperature control and adjustment device, and by setting multiple relays, the temperature control and adjustment device can adjust the temperature of the heating channel in a targeted manner.

A further improvement to the solution of the present invention, the ink droplet optimization system further includes a solute particle recovery device for recovering solute particles generated by the volatilization of satellite droplets, and the solute particle recovery device communicates with the heating channel in the multi-channel heating device. By setting a solute particle recovery device to recover the solute particles generated by the volatilization of the satellite droplets, the solute particle pollution is avoided, and it can be reused.

The present invention also provides a piezoelectric inkjet optimization method applied to printing ink droplets, using the aforementioned piezoelectric inkjet system, and the method includes the following steps:

The central control system issues printing instructions;

The piezoelectric drive module of the piezoelectric inkjet subsystem receives the printing instruction and excites the piezoelectric nozzle to eject ink droplets;

The ejected ink droplets enter the multi-channel heating device in the ink drop optimization system, and the temperature control adjustment device adjusts the temperature of the multi-channel heating device. The heating channel in the multi-channel heating device heats the main ink droplets and satellite droplets entering it. The droplets are completely volatilized by heating, the volume of the main ink droplets is reduced by the heating, and the main ink droplets reach the printed circuit board.

A further improvement to the method of the present invention, the method also comprises the following steps:

The central control system collects the falling image of the ink droplets after coming out of the multi-channel heating device through the ink drop monitoring system, and analyzes whether there are still satellite droplets according to the falling image;

If there is still a satellite droplet, the central control system obtains the serial number of the nozzle that sprays the satellite droplet according to the falling image, and increases the temperature in the heating channel corresponding to the nozzle in the multi-channel heating device through the temperature control adjustment device to eliminate the residual droplet. Satellite droplets that will exist. In the end, almost all the satellite droplets that affect the printing accuracy are volatilized, leaving the main ink droplets with finer sizes to participate in the deposition of the substrate, which greatly improves the printing accuracy and overcomes the limitation of the processing difficulties of small-sized nozzles.

Compared with the prior art, the beneficial effects of the present invention are at least as follows:

(1) The piezoelectric inkjet system applied to high-precision printing ink droplets of the present invention includes a central control system, a piezoelectric inkjet subsystem, an ink droplet monitoring system and an ink droplet optimization system, and each subsystem is controlled by the central control system. Control, and real-time feedback data to the central control system, the control process is highly automated, and high-precision optimization of falling ink droplets can be achieved without human intervention.

(2) The piezoelectric inkjet system and its optimization method applied to high-precision printing ink droplets of the present invention, the ink droplet optimization system adopts a combination of a multi-channel heating device, a temperature control and adjustment device and a solute particle recovery device, and uses a multi-channel heating device. The device can completely volatilize the satellite ink droplets in the channel, and further reduce the main ink droplets, providing technical support for higher-precision printing and display, and overcoming the limitation of the nozzle size that cannot be further reduced. The limitation of the device greatly reduces the production process requirements; at the same time, the solute particle recovery device can recover a small amount of solute particles in the satellite droplets for secondary use, avoiding the pollution of solute particles and greatly reducing the printing cost.

(3) The piezoelectric inkjet system of the present invention applied to high-precision printing ink droplets and the optimization method thereof, the ink droplet monitoring system can continuously collect the entire image during the falling process of the ink droplet, perform image comparison and analysis, and use image segmentation Sequence matching divides the entire image of falling ink droplets into images corresponding to the number of nozzles, and corresponds the segmented images to the nozzle numbers, and then detects whether each segmented image contains small satellite droplets, and feeds back the data results to the data processing module. Control the temperature control device to individually regulate each heating channel; at the same time, in the actual printing process, the number of actual heating channels can be flexibly adjusted in the host computer according to the number of nozzles of different types of nozzles, which can control all nozzles as a whole The state of falling ink droplets can also be specific to the optimization of a single heating channel.

(4) The piezoelectric control system and its optimization method applied to high-precision printing ink droplets of the present invention can finally obtain a highly flat surface. The system and the optimization method are simple and feasible, and have high stability for inkjet printing. It does not add additional process steps, is compatible with large-area thin film preparation, and further promotes the realization of high-performance printed electronic devices.

Description of drawings

Fig. 1 is the data interaction diagram between subsystems of the piezoelectric inkjet system applied to high-precision printing ink droplets of the present invention;

Fig. 2 is the module configuration connection diagram of the piezoelectric inkjet system applied to high-precision printing ink droplets and the optimization method thereof according to the present invention;

3 is a cross-sectional view of a multi-channel heating device for a piezoelectric inkjet system applied to high-precision printing ink droplets according to the present invention;

Fig. 4 is the working flow chart of the piezoelectric inkjet optimization method applied to high-precision printing ink droplets of the present invention;

5 is a schematic diagram of a satellite droplet elimination process applied to the piezoelectric inkjet optimization method for high-precision printing ink droplets of the present invention;

6 is a schematic diagram of the residual satellite drop after heat treatment of the piezoelectric inkjet optimization method applied to high-precision printing ink droplets of the present invention;

FIG. 7 is an image analysis processing process diagram of the piezoelectric inkjet optimization method applied to high-precision printing ink droplets of the present invention.

Detailed ways

In order to make the purposes, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments These are some embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts are within the protection scope of the present invention.

Nowadays, industrial manufacturing has higher and higher requirements for inkjet printing accuracy. For example, in the field of display device manufacturing, in theory, ultra-high-resolution display devices can be realized by inkjet printing technology. However, due to the limitation that the size of the nozzle cannot be further reduced, and Ink drop satellite droplets that cannot be solved in the printing process have seriously restricted the development of this technology. Therefore, an ink droplet monitoring and optimization system in the whole printing process was developed to solve the problems existing in labor and monitoring, and further Overcome the constraints of the size of the nozzle on the development of ultra-precision printing and display, and realize the precise monitoring and elimination of satellite droplets to meet the needs of high-quality printing.

As shown in FIG. 1, a piezoelectric inkjet system applied to printing ink droplets of the present invention includes a central control system 1, a piezoelectric inkjet subsystem 2, an ink droplet monitoring system 4 and an ink droplet optimization system 3. The piezoelectric inkjet subsystem 2 , the ink drop monitoring system 4 and the ink drop optimization system 3 are all regulated by the central control system 1 , and feedback data to the central control system 1 .

In one embodiment of the present invention, as shown in FIG. 2 , the central control system 1 includes a host computer 11 , an image acquisition module 12 , an image analysis module 13 and a data processing module 14 . The image acquisition module 12 is used to collect images of falling ink droplets, the image analysis module 13 is used to analyze whether there are still satellite droplets according to the image of the falling ink droplets; the data processing module 14 is used to obtain the serial number of the nozzle that ejects the satellite droplets, and the host computer Send the temperature control adjustment command to the temperature control adjustment device 32 according to the serial number.

More specifically, the image acquisition module adopts VAS image acquisition software, the image analysis module adopts VDM visual development kit, and the data processing module adopts LabVIEW data processing module. Specifically, as shown in FIG. 2 , the VAS image acquisition software, the VDM visual development package and the LabVIEW data processing module are all integrated in the host computer, and working parameters can be set in the host computer.

In one embodiment of the present invention, the piezoelectric inkjet subsystem 2 includes a piezoelectric driving module 21 , an ink supply assembly 23 and a piezoelectric spray head 22 . The piezoelectric drive module 21 is connected with the central control system 1, the piezoelectric print head 22 includes a plurality of nozzles, the piezoelectric print head 22 is connected with the piezoelectric drive module 21, and the ink supply assembly 23 is connected with the piezoelectric print head 22 to provide all the piezoelectric print heads. Ink is required.

The piezoelectric drive module 21 includes a PCI waveform generating card and a voltage amplifier. The PCI waveform generating card and the host computer transmit data to each other in the form of a PCI communication protocol. The pulse voltage output by the PCI waveform generating card is transmitted to the voltage amplifier through the circuit line. enlarge. Among them, the amplitude of the voltage signal output by the PCI waveform generating card is only 0-10V, which is not enough to drive the piezoelectric actuator in the piezoelectric print head. The ink supply assembly 23 includes a positive and negative air pressure pump and an ink storage bottle, the positive and negative air pressure pump and the ink storage bottle are communicated through a hose, and the ink storage bottle and the ink input end of the piezoelectric nozzle 22 are communicated through a hose, Realize stable delivery of ink. The ink droplets ejected by the piezoelectric head 22 land on the printed circuit board 5 .

In one embodiment of the present invention, the ink drop monitoring system 4 includes a camera 41 , a parallel detection light source 43 and a light source controller 42 . Among them, the camera 41 adopts a high-resolution camera, including a CCD 411 and a magnifying lens 412. The light source controller is connected to the host computer 11, the light source controller is connected to a 220V power supply, and the lead circuit line is connected to the parallel detection light source to control the light source. The switch and the intensity are closely connected, and the light emitted from the parallel detection light source 43 is directed toward the drop direction of the ink drop. The image acquisition of the CCD requires sufficient light for exposure, and the parallel detection light source 43 can provide sufficient light. The purpose of parallelism is to maintain the brightness uniformity of the entire image, so that the pixel values (gray values) of the ink droplets in the image are uniform. Reduce the distraction of post-image processing.

In one embodiment of the present invention, the ink droplet optimization system 3 includes a multi-channel heating device 31 , a temperature control device 32 and a solute particle recovery device 33 .

The multi-channel heating device 31 is provided with a plurality of heating channels 311 corresponding to the nozzles of the piezoelectric spray head 22 , and the temperature control device 32 is used to adjust the temperature of each channel in the multi-channel heating device 31 . More specifically, the ink droplet optimization system 3 is located below the piezoelectric inkjet subsystem 2 , and the heating channel 311 on the multi-channel heating device 31 in the ink droplet optimization system 3 is connected to the piezoelectric nozzle 22 in the piezoelectric inkjet subsystem 2 . The nozzles are set in one-to-one correspondence.

In one embodiment of the present invention, the temperature control and adjustment device 32 includes a multi-channel relay, a single-chip microcomputer and a serial port conversion module. Among them, the single-chip microcomputer adopts TM32 single-chip microcomputer, and the serial port conversion module adopts CH340 serial port conversion module. The STM32 single-chip microcomputer communicates with the host computer through the CH340 serial port conversion module, and the two are connected by a DuPont line. The multi-channel relay is connected to the output pin of the STM32 single-chip microcomputer through a circuit line, and the high and low levels of the pins are used to control each channel of the relay. on and off.

Each heating channel 311 in the multi-channel heating device 31 is provided with a heating element, and each heating element is respectively connected with each branch in the multi-channel relay through a circuit line. After the temperature control regulation command given by the host computer is converted and output by the STM32 single-chip microcomputer, it controls each switch of the multi-channel relay, and then realizes whether the heating channel is heated or not.

Each heating channel 311 in the multi-channel heating device 31 is provided with a recovery through hole 3111 , and each recovery through hole 3111 communicates with the solute particle recovery device 33 through the recovery pipe 6 .

The solute particle recovery device 33 includes a suction pump and a recovery bottle. Specifically, the suction pump is connected to a pipeline between the recovery bottle, and the suction pump can continuously and stably provide negative pressure suction. The recovery bottle and the recovery through hole on the heating channel 311 3111 are communicated through the recovery pipeline 6 .

Among them, the heating element is a heating pad, and the heating pads of each channel are drawn out through circuit wires 7 and connected to each branch of the multi-circuit relay; the recovery pipe 6 is a hose.

When the piezoelectric inkjet system applied to high-precision printing ink droplets provided by the present invention works, the piezoelectric drive module 21 in the piezoelectric inkjet subsystem 2 starts to output pulse voltage signals under the control of the printing instruction of the central control system 1, And under the stable ink supply of the ink supply assembly 23, the piezoelectric nozzle 22 is driven to eject functional material ink droplets, and the main ink droplets and the trailing satellite droplets enter the multi-channel heating device 31 in the ink droplet optimization system 3 together. The satellite droplets with smaller volume are completely volatilized, and the generated fine satellite droplets with residual solid solute particles pass through the through holes in the heating channel 311 in the multi-channel heating device 31 and enter the solute particle recovery device 33 through the hose for secondary use, and The main ink droplets after passing through the multi-channel heating device 31 are further reduced, which overcomes the limitation of the nozzle size on ultra-high-precision printing; at the same time, in order to prevent the satellite droplets ejected from some nozzles from being completely thermally volatilized, the ink drop monitoring system 4 is used. The whole image of falling ink droplets after heat treatment is collected in real time, and the image of falling ink droplets is processed by the central control system, and the nozzle serial number corresponding to the satellite droplet is finally determined, and the heating channel 311 where the falling satellite droplet is located is determined by the temperature control adjustment device 32. Independent warming is carried out, thereby further eliminating satellite droplets. The complete system and optimization method can further improve the high-precision printing process.

The present invention also provides an optimization method for piezoelectric inkjet optimization using the aforementioned piezoelectric inkjet system.

In one embodiment of the present invention, referring to FIG. 4 , a piezoelectric inkjet optimization method applied to high-precision printing ink droplets is provided, including the following steps:

Step 1: Connect the piezoelectric inkjet subsystem 2, the ink droplet monitoring system 4 and the ink droplet optimization system 3 to the central control system 1, and install the corresponding VAS image acquisition software, VDM visual development kit and LabVIEW data in the host computer processing module;

Step 2: The host computer 11 in the central control system 1 gives a printing instruction, and the piezoelectric nozzle 22 in the piezoelectric inkjet subsystem 2 starts under the excitation of the piezoelectric drive module 21 and the continuous ink supply of the ink supply assembly 23 Jet functional material ink droplets;

Step 3: The tail of the main droplet in the falling ink droplets is accompanied by satellite droplets, and the main droplet and satellite droplets enter the multi-channel heating device 31 in the ink droplet optimization system 3 together, and the heating in the channel 311 is heated by the multi-channel heating device 31. After the component is heated, the satellite droplets are completely volatilized, leaving nano-scale solute particles;

Wherein, in one of the embodiments of the present invention, the satellite droplets are one-tenth to one-fifth the size of the main ink droplets, and are completely volatilized after passing through the heating channel.

Step 4: The suction pump in the ink droplet optimization system 3 provides negative pressure suction, and absorbs the nano-scale solute particles produced by the complete volatilization of the satellite droplets into the recovery bottle for secondary use to avoid pollution, while the main ink droplets continue to be affected by gravity Falling, the main ink droplet after passing through the multi-channel heating device 31 volatilizes part of the solvent, and the volume shrinks;

Step 5: As shown in Figure 2 and Figure 7, in order to prevent the satellite droplets ejected by some nozzles from being completely thermally volatilized, the VAS image acquisition software in the host computer uses the high-resolution camera in the ink drop monitoring system 4 to collect the heat treatment in real time. The entire image of the falling ink droplet after

In one embodiment of the present invention, as shown in FIG. 7 , in the above step 5, the high-resolution camera field of view axis is parallel to the movement trajectory of the nozzle, and images of falling ink droplets ejected by all nozzles at the same time can be obtained.

Step 6: As shown in Figure 7, the VDM visual development kit performs multi-step image processing on the falling image, including grayscale conversion, threshold segmentation, and automatically copies and divides the entire image into several sheets of single-nozzle ink according to the number of corresponding nozzles Drop drop images, establish image segmentation sequence matching, and determine whether there are still a small number of satellite droplets;

Among them, in one of the embodiments of the present invention, the grayscale conversion of the image is to convert the color image saved by the host computer into an HSL (color luminance saturation) image, and then extract the luminance plane, which is completely corresponding to the grayscale image. , which is the only color plane that can provide an accurate representation of a grayscale image, which is then converted to a grayscale image.

In one embodiment of the present invention, the threshold segmentation of the image is to first determine a grayscale threshold in the host computer, and divide the pixel group constituting the image into two parts, the pixels smaller than the threshold value appear black, and the pixels larger than the threshold value appear white , so as to convert the image into a single black and white image, the final ink droplet will appear completely black, and the background will become completely white, making the target image have extremely high contrast, eliminating irrelevant objects in the image, and facilitating later satellite droplet detection .

In one embodiment of the present invention, the image segmentation sequence matching is to segment the entire image of falling ink droplets into images corresponding to the number of nozzles, and then correspond the segmented images to the nozzle numbers, and then detect whether each segmented image contains satellite droplets .

Step 7: If there are still a small number of satellite droplets, the data processing module obtains the nozzle serial number corresponding to the satellite droplet ejection, and uses the temperature control and adjustment device 32 to independently heat up the heating channel where the falling ink droplets are located to further eliminate a small number of satellite droplets;

Among them, the temperature control device 32 can not only perform unified temperature control on all the heating channels 311 in the multi-channel heating device 31, but also can adjust the temperature of a heating channel 311 individually. The specific working mode can be set in the host computer. .

Step 8: After thermal volatilization and secondary temperature adjustment, the ink droplets finally deposited on the printing substrate 5 will only contain main ink droplets without satellite droplets, and the smaller ink droplet size overcomes the influence of the nozzle size. The limitations of ultra-high-precision printing period devices can be used to fabricate ultra-high-resolution display devices.

After the above steps, the satellite droplets that affect the printing accuracy will be all volatilized, leaving the main ink droplets with finer size to participate in the deposition of the substrate, which greatly improves the printing accuracy and overcomes the limitation of the processing difficulties of small-sized nozzles.

The above description of the disclosed embodiments enables any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (8)

1. A piezoelectric inkjet system applied to printing ink droplets, characterized in that: comprising a central control system (1), a piezoelectric inkjet subsystem (2) and an ink droplet optimization system (3), the piezoelectric inkjet Both the subsystem (2) and the ink droplet optimization system (3) are connected to the central control system (1) respectively; The piezoelectric inkjet subsystem (2) includes a piezoelectric driving module (21), a piezoelectric printing head (22) and an ink supply assembly (23). The piezoelectric driving module (21) is connected to the central control system (1), and the piezoelectric The print head (22) includes a plurality of nozzles (221), the piezoelectric print head (22) is connected with the piezoelectric drive module (21), and the ink supply assembly (23) is connected with the piezoelectric print head (22); The ink droplet optimization system (3) includes a multi-channel heating device (31) and a temperature control device (32), and the multi-channel heating device (31) is provided with a plurality of heating channels corresponding to the nozzles on the piezoelectric print head (22). (311), the temperature control adjusting device (32) is used to adjust the temperature of each heating channel in the multi-channel heating device (31); It also includes an ink drop monitoring system (4), and the ink drop monitoring system (4) includes a camera (41) for collecting images of ink droplets falling, and the camera is connected to the central control system (1); The central control system (1) includes a host computer (11), an image acquisition module (12), an image analysis module (13) and a data processing module (14), and the image acquisition module (12) collects the whereabouts of ink droplets through a camera (41). Image, the image acquisition module (12) is used to collect images of the falling ink droplets, the image analysis module (13) is used to analyze whether satellite droplets still exist according to the image of the falling ink droplets, and the data processing module (14) is used to obtain ejection satellite droplets The serial number of the nozzle, the upper computer is used to send the temperature control adjustment instruction to the temperature control adjustment device (32) according to the serial number. 2. A piezoelectric inkjet system for printing ink droplets according to claim 1, wherein the ink droplet monitoring system (4) further comprises a light source controller (42) and a parallel detection light source (43), The light source controller (42) is connected with the central control system (1), the parallel detection light source (43) is connected with the light source controller (42), and the outgoing light of the parallel detection light source (43) is directed toward the falling direction of ink droplets. 3. A piezoelectric inkjet system for printing ink droplets according to claim 1, characterized in that: the piezoelectric drive module (21) in the piezoelectric inkjet subsystem (2) comprises a PCI waveform generating card And the voltage amplifier, the PCI waveform generating card is connected with the central control system (1) for communication, and the voltage amplifier is connected with the PCI waveform generating card. 4. A piezoelectric inkjet system for printing ink droplets according to claim 1, characterized in that: the ink supply assembly (23) comprises a pneumatic pump and an ink storage container, and a pipeline between the pneumatic pump and the ink storage container connected, and the ink storage container is communicated with the ink input end of the piezoelectric nozzle (22). 5. A piezoelectric inkjet system for printing ink droplets according to claim 1, characterized in that: a heating element is provided in each heating channel (311) in the multi-channel heating device (31), The temperature control and adjustment device (32) includes a multi-channel relay, a single-chip microcomputer and a serial port conversion module, the output end of the single-chip microcomputer is connected with the multi-channel relay to control the on-off of each branch of the multi-channel relay, and the single-chip microcomputer communicates with the central control system ( 1) Connection, wherein each heating element is electrically connected to each branch in the multi-circuit relay. 6. A piezoelectric inkjet system applied to printing ink droplets according to any one of claims 1-5, characterized in that: the ink droplet optimization system (3) further comprises a solute for recovering the solute produced by the volatilization of satellite droplets A solute particle recovery device (33) for particles, the solute particle recovery device (33) is communicated with a heating channel (311) in the multi-channel heating device (31). 7. A piezoelectric inkjet optimization method applied to printing ink droplets, wherein the piezoelectric inkjet system according to any one of claims 1-6 is adopted, and the method comprises the following steps: The central control system (1) issues printing instructions; The piezoelectric drive module (21) of the piezoelectric inkjet subsystem (2) receives the printing instruction, and excites the piezoelectric nozzle (22) to eject ink droplets; The ejected ink droplets enter the multi-channel heating device (31) in the ink droplet optimization system (3), the temperature control adjusting device (32) adjusts the temperature of the multi-channel heating device (31), and the heating in the multi-channel heating device (31) The channel ( 311 ) heats the main ink droplets and satellite droplets entering it, the satellite droplets are completely volatilized due to the heating, the volume of the main ink droplets is reduced due to the heating, and the main ink droplets reach the printing substrate (5). 8. A piezoelectric inkjet optimization method applied to printing ink droplets according to claim 7, wherein the method further comprises the following steps: The central control system (1) collects the falling images of the ink droplets after coming out of the multi-channel heating device (31) through the ink drop monitoring system (4), and analyzes whether there are still satellite droplets according to the falling images; If there are still satellite droplets, the central control system (1) obtains the serial number of the nozzle that sprays the satellite droplet according to the falling image, and heats the nozzle corresponding to the nozzle in the multi-channel heating device (31) through the temperature control and adjustment device (32). The temperature in the channel (311) increases, eliminating the satellite droplets that will still be present.

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