Piezoelectric ink-jet printing head with large ink amount and piezoelectric ink-jet printer

Abstract

The utility model discloses a piezoelectric ink-jet printing head with a large ink amount and a piezoelectric ink-jet printer. The printing head comprises a driving component, a flow channel component and a spraying hole component. The driving component comprises piezoelectric ceramic and an electrode, and the thickness of the piezoelectric ceramic is 50-400 microns; the thickness of the electrode is greater than 0.07 microns; the flow channel component comprises a flow channel, and the width of the flow channel is greater than 40 microns; the diameter of a spray hole of the spray hole component is greater than 20 microns; the volume of ink droplets emitted by a single hole of the nozzle is larger than 40 picoliters, and the flow of the nozzle is larger than 60 microliters per second.

Description

Technical Field

[0001] The present application relates to the field of inkjet printing, and in particular to a piezoelectric inkjet print head with a large ink volume and a piezoelectric inkjet printer. Background Art

[0002] Waveforms can be designed and optimized based on manual experience, or all possible parameter combinations can be experimentally tested to obtain the optimal parameter settings. For simpler drive voltage waveforms, where only one or two parameters need to be determined, the optimal parameters can be obtained using relevant testing instruments and measurement methods. Currently, some researchers have used CCD cameras to apply a low-amplitude drive voltage to piezoelectric inkjet printheads, causing the liquid level at the nozzle to change without generating ink droplets. The motion of the meniscus at the nozzle is then observed to design and optimize the high-level duration parameters in the drive voltage waveform. Another known technique uses laser-based instruments to detect the radial displacement of a piezoelectric inkjet printhead under different voltage amplitudes, adjusting the voltage amplitude based on the magnitude of the radial displacement. This also improves the efficiency of waveform determination. Because piezoelectric inkjet printhead drive voltage waveforms come in a variety of types, each containing multiple adjustable parameters, existing waveform determination methods are time-consuming and labor-intensive, and may not yield the optimal parameter settings. This can ultimately result in unsatisfactory droplet morphology or substandard size, thus affecting piezoelectric inkjet printing accuracy. Utility Model Content

[0003] In order to solve the problems existing in the prior art, the present application provides a piezoelectric inkjet print head with a large ink volume and a piezoelectric inkjet printer.

[0004] When printing, an inkjet print head sprays ink droplets onto the substrate. When the ink droplets are small, the print quality and speed will be reduced accordingly, thus affecting the performance of the print head. On the other hand, when the ink droplets are large, good printing effects will be achieved.

[0005] In this application, the amount of ink used for better printing results is referred to as a large ink volume. That is, given a fixed number of nozzles on a printhead, the larger the ink droplets ejected, the greater the ink volume ejected by the printhead. In other words, when the droplet volume is greater than 40 or 50 picoliters, which is considered a large droplet, the amount of ink ejected by the printhead is considered a large ink volume. When the droplet volume is greater than this, the printing effect is better, and as the droplet volume increases, the larger the ink volume ejected by the printhead, the better the printing effect.

[0006] In this application, the print head ejects ink droplets downward to perform printing, so the direction in which the ink is ejected is defined as downward, and the opposite direction is defined as upward.

[0007] The specific technical solutions of this application are as follows:

[0008] A piezoelectric inkjet print head with a large ink volume, wherein the print head comprises:

[0009] Driving component, flow channel component, spray hole component;

[0010] The driving member includes piezoelectric ceramics and electrodes,

[0011] The thickness of the piezoelectric ceramic is 50 to 400 microns; the thickness of the electrode is greater than 0.07 microns;

[0012] The flow channel component includes flow channel layers, and flow channels are formed between the flow channel layers;

[0013] The width of the flow channel is greater than 200 microns;

[0014] The spray hole component includes a spray hole layer, and the spray hole is formed on the spray hole layer;

[0015] The thickness of the nozzle layer is less than 150 microns;

[0016] The diameter of the nozzle hole of the nozzle hole component is greater than 20 microns;

[0017] The volume of ink droplets emitted by a single nozzle hole is greater than 40 picoliters, and the nozzle flow rate is greater than 60 microliters per second.

[0018] In a specific embodiment, the thickness of the piezoelectric ceramic is 70 to 300 micrometers; the thickness of the electrode is greater than 0.1 micrometer.

[0019] In one embodiment, the width of the flow channel is greater than 300 microns.

[0020] In a specific embodiment, the diameter of the nozzle hole of the nozzle hole member is greater than 30 microns.

[0021] In a specific embodiment, the volume of ink droplets emitted by a single orifice of the nozzle is greater than 50 picoliters, and the nozzle flow rate is greater than 80 microliters per second.

[0022] In one embodiment, the thickness of the orifice layer is less than 100 microns.

[0023] In a specific embodiment, the print head further includes a circuit board card; the circuit board card provides more than 256 independent driving circuits.

[0024] In one embodiment, the generated driving waveform has a voltage greater than 80 volts and a pulse width greater than 2 microseconds.

[0025] The present application also provides a printing method, which includes using the above-mentioned piezoelectric inkjet print head to perform printing.

[0026] The present application also provides a piezoelectric inkjet printer, which includes the above-mentioned piezoelectric inkjet print head.

[0027] Beneficial effects

[0028] The high-capacity piezoelectric inkjet printhead of this application controls the thickness of the piezoelectric ceramic and electrodes to enable the printhead to eject droplets of appropriate size, thereby improving the quality of printed materials. The nozzle diameter is set to an appropriate diameter in this application, further ensuring that droplets are sprayed more evenly onto the substrate, thereby improving the quality of printed materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a structural diagram of the driving component of this application;

[0030] Figure 2 It is the driving waveform in the embodiment of the present application.

[0031] In the figure, 1, driving component; 11, piezoelectric ceramic; 12, electrode; 2, flow channel component; 21, flow channel; 3, nozzle component; 31, nozzle. DETAILED DESCRIPTION

[0032] The present application is described in detail below. Although specific embodiments of the present application are shown, it should be understood that the present application can be implemented in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present application and to fully convey the scope of the present application to those skilled in the art.

[0033] It should be noted that certain words are used in the specification and claims to refer to specific components. Those skilled in the art should understand that technicians may use different nouns to refer to the same component. This specification and claims do not use the difference in nouns as a way to distinguish components, but use the difference in the functions of the components as the criterion for distinction. As mentioned throughout the specification and claims, "including" or "comprising" are open-ended terms and should be interpreted as "including but not limited to". The subsequent description of the specification is a preferred embodiment of the present application, but the description is based on the general principles of the specification and is not intended to limit the scope of the present application. The scope of protection of this application shall be as defined by the attached claims.

[0034] refer to Figure 1 The present application provides a piezoelectric inkjet print head with a large ink volume. The print head comprises:

[0035] Driving component 1, flow channel component 2, spray hole component 3;

[0036] In this application, the driving component 1, the flow channel 21 component 2 and the nozzle 31 component 3 are planned as a whole, and each component is designed to a suitable size, so that the print head in this application can print better quality items when printing.

[0037] The drive member 1 is located above the flow channel 21 member 2, and the nozzle 31 structure is located below the flow channel 21 member 2. Ink from the print head flows through the flow channel 21 member 2, and then the drive member 1 vibrates to generate driving force, ejecting the ink in the flow channel 21 member 2 from the nozzle 31 member 3.

[0038] The driving member 1 includes a piezoelectric ceramic 11 and an electrode 12;

[0039] The piezoelectric ceramic 11 is fixedly connected to the electrode 12. The electrode 12 is located below the piezoelectric ceramic 11. The piezoelectric ceramic 11 covers the flow channel 21 component 2.

[0040] The electrode 12 is connected to a power source, and the electric energy of the power source is transmitted to the piezoelectric ceramic 11 through the electrode 12. The piezoelectric ceramic 11 vibrates under the action of the electric energy, and then the vibrating piezoelectric ceramic 11 ejects the ink in the flow channel 21 component 2 from the nozzle 31 component 3.

[0041] The thickness of the piezoelectric ceramic 11 is 50 to 400 microns; preferably, the thickness of the piezoelectric ceramic 11 is 70 to 300 microns.

[0042] Specifically, the thickness of the piezoelectric ceramic 11 is: 50 microns, 60 microns, 70 microns, 80 microns, 90 microns, 100 microns, 110 microns, 120 microns, 130 microns, 140 microns, 150 microns, 160 microns, 170 microns, 180 microns, 190 microns, 200 microns, 210 microns, 220 microns, 230 microns, 240 microns, 250 microns, 260 microns, 270 microns, 280 microns, 290 microns, 300 microns, 310 microns, 320 microns, 330 microns, 340 microns, 350 microns, 360 microns, 370 microns, 380 microns, 390 microns, and 400 microns.

[0043] When the thickness of the piezoelectric ceramic 11 is small, the durability of the piezoelectric ceramic 11 will be reduced, thereby shortening the service life of the piezoelectric ceramic 11 and the print head. When the thickness of the piezoelectric ceramic 11 increases, the amplitude of the vibration of the piezoelectric ceramic 11 will decrease accordingly, thereby making the size of the ink droplets ejected under the vibration of the piezoelectric ceramic 11 smaller, thereby affecting the quality or speed of the printed material. Therefore, in this application, the thickness of the piezoelectric ceramic 11 is set between 50 and 400 microns, so that the piezoelectric ceramic 11 can increase the service life while ensuring printing quality.

[0044] The thickness of the electrode 12 is greater than 0.07 micrometers; preferably, the thickness of the electrode 12 is greater than 0.1 micrometers.

[0045] Specifically, the thickness of the electrode 12 is: 0.07 micron, 0.08 micron, 0.09 micron, 0.1 micron, 0.11 micron, 0.12 micron, 0.13 micron, 0.14 micron, 0.15 micron, 0.16 micron, 0.17 micron, 0.18 micron, 0.19 micron, 0.2 micron, 0.21 micron, 0.22 micron, 0.23 micron, 0.24 micron, 0.25 micron, 0.26 micron, 0.27 micron, 0.28 micron, 0.29 micron, 0.3 micron, 0.35 micron, 0.4 micron, 0.45 micron, 0.5 micron, 0.55 micron, 0.6 micron, 0.65 micron, 0.7 micron, 0.75 micron, 0.8 micron, 0.85 micron, 0.9 micron, 0.95 micron, and 1 micron.

[0046] The electrode 12 is disposed on the piezoelectric ceramic 11 to supply power to the piezoelectric ceramic 11, thereby causing the piezoelectric ceramic 11 to vibrate. When the electrode 12 is thinner, the electrode 12 can withstand less electrical energy, resulting in a decrease in the current or voltage that the electrode 12 can withstand. This reduces the vibration amplitude of the piezoelectric ceramic 11, reducing the volume of the ejected liquid. As the thickness of the electrode 12 increases, the ejected ink droplets gradually increase. Therefore, in this application, the thickness of the electrode 12 is set to be greater than 0.07 microns; this allows the printhead to eject ink droplets of appropriate size while maintaining the thickness of the piezoelectric ceramic 11 within an appropriate range and, combined with the appropriate thickness of the electrode 12, enabling the printhead to eject ink droplets of appropriate size.

[0047] However, the thicker electrode 12 will affect the vibration of the piezoelectric ceramic 11 .

[0048] The flow channel 21 component 2 includes flow channel layers, and the flow channel 21 is formed between the flow channel layers.

[0049] The flow channel layer is located below the electrode layer 12. The gap between the flow channel layers for ink to flow into is the flow channel 21. The piezoelectric ceramic 11 covers the top of the flow channel 21. Therefore, when the piezoelectric ceramic 11 vibrates, it can vibrate the ink droplets in the flow channel 21 out of the flow channel 21.

[0050] The width of the flow channel 21 is greater than 200 microns; preferably, the width of the flow channel 21 is greater than 300 microns.

[0051] Specifically, the width of the flow channel 21 is: 200 microns, 220 microns, 240 microns, 250 microns, 260 microns, 280 microns, 300 microns, 320 microns, 340 microns, 350 microns, 360 microns, 380 microns, 400 microns, 420 microns, 440 microns, 450 microns, 460 microns, 480 microns, 500 microns, 520 microns, 540 microns, 550 microns, 560 microns, 580 microns, 600 microns, 620 microns, 640 microns, 650 microns, 660 microns, 680 microns, 700 microns, 750 microns, 800 microns, 850 microns, 900 microns, 950 microns, and 1000 microns.

[0052] The flow channel 21 is a channel for ink flow and is located above the nozzle 31 component 3. When the piezoelectric ceramic 11 vibrates, the ink in the flow channel 21 is squeezed out of the nozzle 31 component 3 to form ink droplets.

[0053] In the art, the width of the flow channel layer is generally consistent with the effective width of the piezoelectric ceramic 11. Therefore, when the width of the flow channel 21 is set to be wider, the width of the piezoelectric ceramic 11 located above it also increases accordingly. This leads to an increase in the unit ink area of ​​the nozzle hole 31 component 3 located below it, thereby increasing the flow rate of ink ejected by the nozzle hole 31 component 3, further helping to improve the quality of printed products.

[0054] The nozzle hole 31 component 3 includes a nozzle hole layer, on which nozzle holes 31 for ink droplets to pass through are formed.

[0055] The nozzle layer is located below the flow channel 21 and has multiple nozzles 31 evenly distributed on it. When the piezoelectric ceramic 11 vibrates, the ink in the flow channel 21 is pressurized, squeezing the ink out of the nozzles 31. The ink is then ejected from the nozzles 31 in the form of ink droplets, which then land on the substrate.

[0056] The thickness of the orifice layer is less than 150 microns; preferably, the thickness of the orifice layer is less than 100 microns.

[0057] Specifically, the thickness of the orifice layer is 150 microns, 145 microns, 140 microns, 135 microns, 130 microns, 125 microns, 120 microns, 115 microns, 110 microns, 105 microns, 100 microns, 95 microns, 90 microns, 85 microns, 80 microns, 75 microns, 70 microns, 65 microns, 60 microns, 55 microns, and 50 microns.

[0058] The orifice layer is located below the flow channel layer, and a nozzle 31 for ink ejection is formed on the orifice layer; the orifice layer is fixedly connected to the flow channel layer, so the hydraulic pressure caused by the ejection of ink droplets from the nozzle 31 is borne by the orifice layer. Therefore, if the thickness of the orifice layer is small, it will cause damage to the orifice layer.

[0059] On the other hand, since the nozzle 31 is opened on the nozzle layer, the depth of the nozzle 31 is equal to the thickness of the nozzle layer. When the thickness of the nozzle layer increases, the depth of the nozzle 31 will increase, causing the resistance of the ink droplets passing through the nozzle 31 to increase, making it difficult for the ink to be ejected from the nozzle, thereby causing the volume of the ink droplets ejected from the nozzle 31 to decrease.

[0060] Therefore, in this application, the thickness of the nozzle layer is set to be less than 150 microns, preferably less than 100 microns, so that ink droplets can be ejected from the nozzles 31 more easily and the ejected ink droplets can have a larger volume, thereby helping to improve the service life of the print head and print quality.

[0061] The diameter of the nozzle hole 31 of the nozzle hole 31 component 3 is greater than 20 microns; preferably, the diameter of the nozzle hole 31 of the nozzle hole 31 component 3 is greater than 30 microns.

[0062] Specifically, the diameter of the nozzle 31 is: 20 microns, 21 microns, 22 microns, 23 microns, 24 microns, 25 microns, 26 microns, 27 microns, 28 microns, 29 microns, 30 microns, 31 microns, 32 microns, 33 microns, 34 microns, 35 microns, 36 microns, 37 microns, 38 microns, 39 microns, 40 microns, 45 microns, 50 microns, 55 microns, 60 microns, 65 microns, 70 microns, 75 microns, 80 microns, 85 microns, 90 microns, 95 microns, and 100 microns.

[0063] When the ink passes through the nozzle layer, it is ejected from the nozzle 31 to form ink droplets.

[0064] When the diameter of the nozzle hole 31 is small, the flow resistance of its structure increases, making it difficult for the ink to be ejected from the nozzle hole 31. Even under the squeezing action of the piezoelectric ceramic 11, the ink is ejected from the nozzle hole 31 with a smaller diameter, and the volume of the droplets formed is also smaller, which greatly reduces the printing speed of the print head.

[0065] Therefore, in this application, the diameter of the nozzle 31 is set to be greater than 20 microns, so that the volume of the ink droplets ejected from the nozzle 31 is larger, thereby improving the printing speed, improving the printing quality and increasing the service life of the print head.

[0066] The volume of ink droplets emitted by the nozzle 31 is greater than 40 picoliters; preferably, the volume of ink droplets emitted by a single nozzle of the nozzle is greater than 50 picoliters.

[0067] Specifically, the volume of ink droplets emitted by the nozzle 31 is: 40 picoliters, 41 picoliters, 42 picoliters, 43 picoliters, 44 picoliters, 45 picoliters, 46 picoliters, 47 picoliters, 48 ​​picoliters, 49 picoliters, 50 picoliters, 51 picoliters, 52 picoliters, 53 picoliters, 54 picoliters, 55 picoliters, 56 picoliters, 57 picoliters, 58 picoliters, 59 picoliters, 60 picoliters, 61 picoliters, 62 picoliters, 63 picoliters, 64 picoliters, 65 picoliters, 66 picoliters, 67 picoliters, 68 picoliters, 69 picoliters, 70 picoliters, 75 picoliters, 80 picoliters, 85 picoliters, 90 picoliters, 95 picoliters, and 100 picoliters.

[0068] The ink droplets emitted by a single nozzle of the nozzle are the ink droplets ejected from a single nozzle on the nozzle.

[0069] When the ink droplets ejected from the nozzle orifice 31 are small in volume, the flow rate through the nozzle head and nozzle orifice 31 is also reduced, which in turn reduces printing speed and printing efficiency. On the other hand, when the ink droplets are small, to reduce ink splashing, a small distance must be maintained between the nozzle orifice 31 and the substrate. This increases contact friction between the substrate and the print head, causing wear and tear on the print head and shortening its service life.

[0070] Therefore, the present application controls the volume of ink droplets emitted from the nozzle 31 to be greater than 40 picoliters, and the preferred ink droplet volume is greater than 50 picoliters, so that the ejected ink droplets are larger, and sufficient ink droplets can be quickly ejected on the substrate to increase the printing speed. At the same time, ejecting larger ink droplets can also effectively increase the printing height, thereby reducing the possibility of wear between the substrate and the print head and increasing the service life of the print head.

[0071] The nozzle flow rate is greater than 60 microliters per second; preferably, the nozzle flow rate is greater than 80 microliters per second.

[0072] Specifically, the nozzle flow rate is: 60 microliters per second, 61 microliters per second, 62 microliters per second, 63 microliters per second, 64 microliters per second, 65 microliters per second, 66 microliters per second, 67 microliters per second, 68 microliters per second, 69 microliters per second, 70 microliters per second, 71 microliters per second, 72 microliters per second, 73 microliters per second, 74 microliters per second, 75 microliters per second, 76 microliters per second, 77 microliters per second, 78 microliters per second, 79 microliters per second, 80 microliters per second, 81 microliters per second, 82 microliters per second, 83 microliters per second, 84 microliters per second, 85 microliters per second per second, 86 microliters per second, 87 microliters per second, 88 microliters per second, 89 microliters per second, 90 microliters per second, 91 microliters per second, 92 microliters per second, 93 microliters per second, 94 microliters per second, 95 microliters per second, 96 microliters per second, 97 microliters per second, 98 microliters per second, 99 microliters per second, 100 microliters per second, 105 microliters per second, 110 microliters per second, 115 microliters per second, 120 microliters per second, 125 microliters per second, 130 microliters per second, 135 microliters per second, 140 microliters per second, 145 microliters per second, and 150 microliters per second.

[0073] Printhead flow rate refers to the volume of ink droplets ejected by all nozzles per unit time. Printhead flow rate is closely related to the quality of the printed material and printing speed. The greater the printhead flow rate, the more ink is ejected per unit time, resulting in more ink on the printed material and higher quality. Therefore, to improve print quality and ensure that the printed material is clear, without missing parts, and the printed content is complete, sufficient ink droplets must be sprayed onto the substrate. Consequently, as the printhead flow rate increases, the quality of the printed material also improves. However, when the printhead flow rate is low, the quality of the printed material may be significantly reduced or the yield rate of the printed material may be reduced. For example, the printed material may contain missing content or be blurred. On the other hand, when the printhead flow rate is low, in order to improve print quality and ensure that a sufficient amount of ink droplets per unit area on the substrate is applied, the printhead movement speed must be reduced, which further slows down the printing speed and reduces printing efficiency.

[0074] Therefore, in this application, the nozzle flow rate is set to be greater than 60 ml / s, and preferably greater than 80 ml / s. This allows the print head in this application to maintain a suitable printing speed while also producing high-quality prints, thereby improving print quality while increasing printing speed.

[0075] The print head further includes a circuit board card (not shown in the figure); the circuit board card provides more than 256 independent driving circuits.

[0076] The circuit board card is located between the power supply and the electrode 12 and is used to control the frequency or voltage of the current applied to the electrode 12 and the piezoelectric ceramic 11 .

[0077] Specifically, the number of independent drive circuits provided by the circuit board card is: 256, 320, 384, 448, 512, 576, 640, 704, 768, 832, 896, 960, 1024, 1088, 1152, 1216, 1280, 1344, 1408, 1472, 1536, and 1600.

[0078] As the number of driving circuits on the circuit card increases, the nozzle flow rate will also increase, so that the print head can eject more ink droplets per unit time, thereby limiting the printing speed of the print head.

[0079] The driving waveform is a rectangular wave electrical signal with a specific voltage and pulse width.

[0080] The voltage of the driving waveform refers to the magnitude of the effective voltage that can be applied to the electrodes.

[0081] Pulse width usually refers to the period during which a pulse can reach its maximum value in the electronics field.

[0082] The voltage of the generated driving waveform is greater than 80 volts and the pulse width is greater than 2 microseconds.

[0083] It means that when the power passes through the circuit board card, the electric energy will be transmitted to the electrode 12 in the form of greater than 80 volts and a pulse width greater than 2 microseconds.

[0084] Specifically, the voltage of the driving waveform is: 80 volts, 82 volts, 84 volts, 86 volts, 88 volts, 90 volts, 92 volts, 94 volts, 96 volts, 98 volts, 100 volts, 102 volts, 104 volts, 106 volts, 108 volts, 110 volts, 112 volts, 114 volts, 116 volts, 118 volts, 120 volts, 125 volts, 130 volts, 135 volts, 140 volts, 145 volts, and 150 volts.

[0085] When the voltage of the driving waveform increases, the voltage applied to the piezoelectric ceramic 11 increases accordingly, thereby increasing the vibration amplitude of the piezoelectric ceramic 11 accordingly. Furthermore, the volume of the ink droplets ejected by the piezoelectric ceramic 11 squeezing the flow channel 21 also increases accordingly.

[0086] Therefore, in this application, the voltage of the driving waveform is set to be greater than 80 volts, thereby making the ejected ink droplets larger to improve the printing quality.

[0087] Specifically, the pulse width of the driving waveform is: 2 microseconds, 3 microseconds, 4 microseconds, 5 microseconds, 6 microseconds, 7 microseconds, 8 microseconds, 9 microseconds, 10 microseconds, 11 microseconds, 12 microseconds, 13 microseconds, 14 microseconds, 15 microseconds, 16 microseconds, 17 microseconds, 18 microseconds, 19 microseconds, 20 microseconds, 25 microseconds, 30 microseconds, 35 microseconds, 40 microseconds, 45 microseconds, and 50 microseconds.

[0088] As the drive pulse width increases, the duration of maximum voltage applied to the piezoelectric ceramic 11 increases, increasing the vibration amplitude of the piezoelectric ceramic 11 and, in turn, the compression of the piezoelectric ceramic 11 on the flow channel 21. Consequently, when ink droplets are ejected from the nozzle orifice 31, the volume of the ink droplets also increases accordingly. In this application, setting the pulse width to greater than 2 microseconds increases the number of droplets ejected from the nozzle orifice 31, thereby improving print quality and speed.

[0089] The present application also provides a printing method, which includes using the above-mentioned piezoelectric inkjet print head to perform printing.

[0090] The present application also provides a piezoelectric inkjet printer, which includes the above-mentioned piezoelectric inkjet print head.

[0091] Example 1

[0092] The present application provides a large ink volume inkjet print head, the ink droplet volume ejected by the nozzle 31 of the print head is 50 picoliters, the number of nozzles 31 on the print head is 1024, and the nozzle flow rate is 800 microliters per second; the voltage of the driving waveform is 80 volts and the pulse width is 5 microseconds. The specific driving waveform is as follows Figure 2 shown.

[0093] The dimensions of the various components in the print head are shown below.

[0094] The thickness of the piezoelectric ceramic 11 is 100 microns; the thickness of the electrode 12 is 0.2 microns;

[0095] The width of the flow channel 21 is 500 μm;

[0096] The diameter of the nozzle hole 31 in the nozzle hole member 3 is 40 microns, and the thickness of the nozzle hole layer is 60 microns;

[0097] The number of independent driving circuits provided by the circuit board is 1024, the driving waveform voltage generated is 80 volts, the pulse width is 2 microseconds, and the frequency of ink droplet emission in the nozzle 31 is 15KHz.

[0098] In this paper, the various parameters of the print head are adjusted before printing, and the printed material conditions are recorded.

[0099] In the present application, the thicknesses of the piezoelectric ceramic 11, the electrode 12 and the nozzle layer are manufactured with preset dimensions when the print head is prepared, and then the use effect of the print head is recorded.

[0100] Example 2

[0101] In this embodiment, a single orifice of a nozzle (ie, nozzle hole) is made to emit ink droplets of different sizes, and the printing quality of the printed document is recorded.

[0102] Record the different ink drop sizes and the corresponding print quality in the table below.

[0103] Table 1

[0104] Ink drop size / picolitre Printing quality Solution 1 20 Poor Option 2 30 Poor Option 3 40 Difference Option 4 50 good Option 5 60 good Option 6 70 good Option 7 80 very good

[0105] When judging the printing quality of printed documents, it can be summarized as follows:

[0106] The image is complete, without missing parts, clear and not blurred, and has no flying spots, which is defined as very good;

[0107] The graphics are complete and intact, with jagged edges and a small number of flying spots, which is defined as good;

[0108] Graphics with missing or slightly missing parts, ghosting at the edges, or ink flying or a large amount of ink flying are defined as poor.

[0109] In this application, when recording the size of ink droplets, a weighing method is generally used to calculate the size of the ink droplets.

[0110] Specifically: Assume that the printing frequency is 20KHz; print 1200K*1024 ink droplets at a time (print for 1 minute), weigh them and divide by the total number of ink droplets to get the size of a single ink droplet.

[0111] Therefore, in this application, the measurement is performed by calculating the average value of the ink droplet size.

[0112] The above method measures ink droplet size by measuring the total size of multiple droplets and then calculating the size of individual droplets. This reduces the difficulty of measuring smaller droplets and increases the accuracy of droplet size measurements. The droplet size deviation measured using this method is ≤10%, resulting in highly accurate droplet size data.

[0113] As can be seen from Example 2, while the printing quality remains poor at a droplet volume of 40 picoliters, it improves compared to smaller droplet volumes. Furthermore, when the droplet volume exceeds 50 picoliters, the printing quality improves. The large droplets ejected during printing achieve a high ink volume from the printhead, resulting in excellent printing results.

[0114] As can be seen from Example 2, as the volume of the ink droplets increases, the quality of the printed product becomes better, and the nozzle flow rate also increases accordingly.

[0115] Example 3

[0116] In this embodiment, the nozzle flow rates are controlled at different numbers, and the usage of the print head at different nozzle flow rates is recorded.

[0117] Table 2

[0118]

[0119] Print head print volume refers to the amount of ink that the print head prints on the substrate per unit time.

[0120] During printing, in order to ensure the printing quality, enough ink is printed on the unit area of ​​the substrate, so that the printed file can achieve a very good effect such as being more complete, without missing parts, clear and not blurred, and without flying dots.

[0121] As can be seen from this embodiment, in actual applications, when printing the same volume of ink on a substrate, larger ink droplets and greater nozzle flow rate result in faster printing speeds. Furthermore, greater nozzle flow rate and larger droplet volume increase the effective print height (height from the substrate) of the printhead; this means the printhead is less likely to rub against the substrate, further extending the printhead's service life.

[0122] When the printhead sprays enough ink per unit area of ​​the substrate, the ink droplets are small, requiring either an increase in droplet velocity or a decrease in printing speed. Spraying larger droplets, on the other hand, increases printing speed and height, increasing the distance between the substrate and the printhead, thereby reducing wear on the printhead and, ultimately, extending the printhead's lifespan.

[0123] Example 4

[0124] In this embodiment, by setting piezoelectric ceramics 11 of different thicknesses and supplementing them with two electrodes 12 of different thicknesses, the dimensions of other components are the same as the data in Example 1, and then the relationship between the piezoelectric ceramics 11 and the ink droplet size is calculated, and the ink droplet size at different piezoelectric ceramic 11 thicknesses is recorded.

[0125] Table 3

[0126]

[0127]

[0128] In the present application, the piezoelectric ceramic 11 is manufactured by a thinning and polishing method, and the processing progress is ±2 μm; therefore, by controlling the processing progress, it is possible to manufacture print heads with piezoelectric ceramics 11 of different thicknesses.

[0129] During manufacture, the electrode 12 is prepared using a deposition method, including steps such as sputtering, evaporation, and electroplating. The processing accuracy of the electrode 12 is ±5 nm. When depositing the electrode 12, the preparation process can be changed to achieve the preparation of electrodes 12 of different thicknesses on the print head.

[0130] In this embodiment, by setting the piezoelectric ceramic 11 to have different thicknesses and providing two electrodes 12 with different thicknesses, it can be seen that when the piezoelectric ceramic 11 is thinner, the ink droplets that can be produced are larger.

[0131] However, the thickness of the piezoelectric ceramic 11 in this application is already extremely small. Therefore, if the thickness of the piezoelectric ceramic 11 is further reduced, on the one hand, the production cost of the piezoelectric ceramic 11 will be greatly increased. On the other hand, the bending fatigue life of the thinner piezoelectric ceramic 11 will also be correspondingly reduced, further increasing the cost of using the print head.

[0132] The thicker the electrode 12, the larger the ink droplets produced. Therefore, the print head in this application sets a reasonable thickness of the piezoelectric ceramic 11 and the electrode 12, so that the print head can print high-quality prints and also prolong the service life of the print head.

[0133] Example 5

[0134] In this embodiment, electrodes 12 of different thicknesses are set on the piezoelectric ceramic 11, and the relationship between the thickness of the electrode 12 and the ink droplet size is calculated. The dimensions of other components are the same as the data in Example 1, and the ink droplet size at different electrode 12 thicknesses is recorded.

[0135] Table 4

[0136]

[0137]

[0138] In this embodiment, two thin-thick electrodes 12 are added. When the thickness of the electrodes 12 is small, even if the thickness of the piezoelectric ceramic 11 is significantly reduced, it is difficult to increase the volume of the droplet to greater than 40 or 50 picoliters. Furthermore, when the thickness of the piezoelectric ceramic 11 is reduced, the service life of the piezoelectric ceramic 11 is significantly reduced. In addition, thinner electrodes 12 are prone to overload and failure. Therefore, the thickness of the electrodes 12 is set to be greater than 0.07 microns, and preferably the thickness of the electrodes 12 is greater than 0.1 microns.

[0139] Example 6

[0140] In this embodiment, flow channels 21 of different widths are provided, and the dimensions of other components are the same as those in embodiment 1. The flow rates of the nozzles at different widths of the flow channels 21 are recorded.

[0141] Table 5

[0142]

[0143]

[0144] From this embodiment, it can be seen that when the width of the flow channel 21 is larger, the nozzle flow rate and the ink droplet volume will also increase accordingly.

[0145] In this application, when measuring the nozzle flow rate, nozzle flow rate = single nozzle hole flow rate * number of nozzle holes.

[0146] Among them, the flow rate of a single nozzle = the volume of the emitted ink droplets * the emission frequency.

[0147] For example: the number of nozzle holes = 1024; the volume of the emitted ink droplets = 80 picoliters; the emission frequency = 20 kHz; then the flow rate of the nozzle at this time = 80 picoliters * 20 kHz * 1024 = 1638 microliters / second.

[0148] The deviation of the flow rate calculation using the above method is generally within the range of ≤10%, which has extremely high measurement accuracy.

[0149] In the art, piezoelectric ceramic 11 is typically positioned directly above flow channel 21 to seal it. Therefore, the width of the flow channel layer is equal to or similar to the width of piezoelectric ceramic 11. As the width of flow channel 21 increases, the width of piezoelectric ceramic 11 also increases accordingly. Furthermore, the ink droplets ejected from nozzle 31 also increase in size due to the larger flow channel 21 and piezoelectric ceramic 11.

[0150] On the other hand, when the width of the flow channel 21 increases, the unit area of ​​the flow channel 21 corresponding to each nozzle 31 also increases accordingly. When the piezoelectric ceramic 11 vibrates, a larger amount of ink will be squeezed out of the nozzle 31, thereby increasing the droplets ejected from the nozzle 31.

[0151] Similarly, the above method can also be used to reversely calculate the volume of a single ink droplet by measuring the volume of ink ejected by the print head per unit time.

[0152] In this application, the width of the flow channel 21 is set to be greater than 200 microns; preferably, the width of the flow channel 21 is greater than 300 microns. This ensures that the ink droplets ejected by the printhead are of sufficient size. This also controls the flow rate of the printhead within an appropriate range, thereby increasing the printing speed of the printhead.

[0153] Example 7

[0154] In this embodiment, the diameter of the nozzle 31 in the nozzle member 3 is set to different sizes while the nozzle layer thickness remains unchanged. The sizes of other components are the same as those in embodiment 1. The ink droplet sizes at different nozzle 31 diameters are recorded.

[0155] Table 6

[0156] Nozzle diameter / micron Ink drop size / picolitre Solution 1 10 5 Option 2 15 10 Option 3 20 20 Option 4 40 80 Option 5 60 90 Option 6 80 150 Option 7 100 200

[0157] From this embodiment, it can be seen that when the diameter of the nozzle hole 31 increases, the size of the ink droplet will also increase accordingly. However, when the diameter of the nozzle hole 31 is too large, it is easy to cause leakage.

[0158] Example 8

[0159] In this embodiment, the nozzle layer is set to different thicknesses and two nozzles 31 with different diameters are set for comparison. The dimensions of other components are the same as those in Example 1. The ink droplet sizes at different nozzle layer thicknesses are recorded.

[0160] Table 7

[0161]

[0162]

[0163] It can be seen from this embodiment that when the thickness of the nozzle hole layer increases, the ink droplets generated will also decrease accordingly. This is also applicable when the diameters of the nozzle holes 31 are different.

[0164] However, when the nozzle layer is thicker, the difference between the ink droplets produced will become smaller even if the nozzle hole 31 diameter is increased. Therefore, when using a thicker nozzle layer, if the volume of the ejected ink droplets is to be similar, the nozzle hole 31 diameter must be larger than the conventional size.

[0165] Therefore, the present application defines the thickness of the nozzle layer as less than 100 microns. Within this range, the diameter of the nozzle 31 is roughly linearly related to the ink droplet size, making it easier to control the volume of the ink droplet during design and manufacturing.

[0166] However, a thinner nozzle layer will increase manufacturing costs, shorten service life, and make the inkjet head more susceptible to damage. Therefore, those skilled in the art can select a nozzle layer that is not too thin according to actual conditions.

[0167] Example 9

[0168] In this embodiment, the effect of different numbers of independent circuits and different circuit boards on ink droplet size or nozzle flow rate was tested. The other component dimensions were the same as those in Example 1, and the ink droplet size or nozzle flow rate under different numbers of independent circuits was recorded.

[0169] Table 8

[0170] Number of independent circuits Nozzle flow rate / μl per second Solution 1 150 120 Option 2 200 160 Option 3 250 200 Option 4 256 204.8 Option 5 300 240 Option 6 350 280

[0171] As can be seen from this embodiment, when the number of independent circuits increases, the nozzle flow rate will also increase accordingly. Moreover, as the number of independent circuits increases, the nozzle flow rate and the number of independent circuits are linearly related.

[0172] Example 10

[0173] In this embodiment, the voltage of the driving waveform of the circuit board card is controlled at different values, and the relationship between the voltage and the nozzle flow or ink droplet size is calculated. The dimensions of other components are the same as the data in Example 1, and the ink droplet size or nozzle flow at different driving waveform voltages is recorded.

[0174] Drive waveform voltage / volts Pulse Width Ink drop size / picolitre Solution 1 40 5 0 Option 2 50 5 30 Option 3 70 5 40 Option 4 80 5 50 Option 5 90 5 60 Option 6 100 5 80 Option 7 150 5 100

[0175] From this embodiment, it can be seen that the larger the drive waveform voltage, the larger the ink droplet volume. Furthermore, when the drive waveform voltage is low, the print head cannot eject ink droplets, and therefore the droplet volume cannot be measured. Therefore, in this application, the drive waveform voltage is set to greater than 80 volts to eject ink droplets of sufficient volume.

[0176] Example 11

[0177] In this embodiment, the relationship between the pulse width and the nozzle flow or ink droplet size is calculated by controlling the pulse width of the circuit board card at different values ​​while keeping the driving waveform voltage unchanged. The dimensions of other components are the same as the data in Example 1, and the ink droplet size or nozzle flow at different pulse widths is recorded.

[0178]

[0179]

[0180] It is clear from this embodiment that as the pulse width increases, the size of the ink droplets produced also increases accordingly. When the pulse width is small, the volume of the ejected ink droplets is small, and even with a significant increase in the voltage, it is difficult to achieve an ink droplet size greater than 50 picoliters. While significantly increasing the voltage, the print head becomes more dangerous during use, and when the voltage is too high, it can damage the internal parts of the print head, increasing the risk of using the print head. Furthermore, when the pulse width is increased to a larger value, the increase in the volume of the ejected ink droplets becomes negligible. Therefore, when the pulse width is increased to a larger range, the effect of the pulse width on the ink droplet volume will also decrease accordingly.

[0181] If the voltage is too high, the bending amplitude of the piezoelectric ceramic will be too large, thereby reducing the fatigue life of the piezoelectric ceramic and the service life of the print head.

[0182] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A piezoelectric inkjet print head with a large ink volume, characterized in that: The print head comprises: Driving component, flow channel component, spray hole component; The driving member includes piezoelectric ceramics and electrodes, The thickness of the piezoelectric ceramic is 50 to 400 microns; the thickness of the electrode is greater than 0.07 microns; The flow channel component includes flow channel layers, and flow channels are formed between the flow channel layers; The width of the flow channel is greater than 200 microns; The spray hole component includes a spray hole layer, and the spray hole is formed on the spray hole layer; The thickness of the orifice layer is less than 150 microns; The diameter of the nozzle hole of the nozzle hole member is greater than 20 microns.

2. The print head according to claim 1, wherein The thickness of the piezoelectric ceramic is 70 to 300 microns; the thickness of the electrode is greater than 0.1 microns.

3. The print head according to claim 1, wherein The width of the flow channel is greater than 300 microns.

4. The print head according to claim 1, wherein: The diameter of the nozzle hole of the nozzle hole component is greater than 30 microns.

5. The print head according to claim 1, wherein: The thickness of the orifice layer is less than 100 microns.

6. The print head according to any one of claims 1 to 5, characterized in that: The print head further includes a circuit board card; the circuit board card provides more than 256 independent driving circuits.

7. The print head according to any one of claims 1 to 5, characterized in that: The voltage of the driving waveform is greater than 80 volts and the pulse width is greater than 2 microseconds.

8. A piezoelectric inkjet printer, characterized in that: It comprises the piezoelectric inkjet print head according to any one of claims 1 to 7.

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