Piezoelectric ink-jet printing head with large ink amount

Abstract

The invention discloses a piezoelectric ink-jet printing head with a large ink amount. 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, in particular to a piezoelectric inkjet printhead with large ink volume. BACKGROUND

[0002] The waveform is designed and optimized based on artificial experience, or all possible parameter combinations are tested experimentally to obtain the optimal parameter setting. For relatively simple drive voltage waveforms and in the case where only one or two parameters need to be determined, the optimal parameters can be obtained through relevant test instruments and measurement methods. Currently, some people have used CCD cameras to apply low-voltage amplitude drive voltage to piezoelectric inkjet printheads to change the liquid surface at the nozzle but not produce ink droplets, and observe the motion state of the meniscus at the nozzle to design and optimize the high-level time parameter in the drive voltage waveform. There is also a known technology that uses relevant instruments with lasers to detect the radial displacement of the piezoelectric inkjet printhead under the action of different voltage amplitudes, and adjusts the size of the voltage amplitude according to the size of the radial displacement, which can also improve the efficiency of determining the waveform. Since there are many types of drive voltage waveforms for piezoelectric inkjet printheads, and each waveform contains multiple adjustable parameters, the existing waveform determination method is time-consuming and laborious, and may not be able to obtain the optimal parameter setting, which may ultimately result in an undesirable ink droplet morphology or substandard size, thereby affecting the printing accuracy of the piezoelectric inkjet printhead. SUMMARY

[0003] To solve the problems in the prior art, the present application provides a piezoelectric inkjet printhead with large ink volume.

[0004] When the inkjet printhead prints, it will eject ink droplets onto the receiving material. When the volume of the ink droplets is small, the printing quality and speed will be reduced accordingly, thus affecting the use of the printhead. When the ejected ink droplets have a large volume, they have good printing effects.

[0005] In the present application, the ink volume used when the printing effect is good is referred to as large ink volume, that is, when the number of ejection orifices on the printhead is determined, the larger the ejected ink droplets, the larger the ink volume ejected by the printhead. In other words, when the volume of the ink droplets is greater than 40 picoliters or 50 picoliters, it is referred to as large ink droplets, and the ink volume ejected by the printhead is large ink volume. When the volume of the ink droplets is greater than this volume, the printing effect is better and the larger the volume of the ink droplets, the larger the ink volume ejected by the printhead, and the better the printing effect.

[0006] In the present application, the printhead ejects ink droplets downward to print. Therefore, the direction in which the ink is ejected is defined as downward, and vice versa.

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

[0008] 1. A piezoelectric inkjet printhead with large drop volume, wherein the printhead comprises:

[0009] a drive member, a flow channel member, a nozzle member;

[0010] the drive member comprises a piezoelectric ceramic and an electrode,

[0011] the piezoelectric ceramic has a thickness of 50-400 microns; the electrode has a thickness of greater than 0.07 microns;

[0012] the flow channel member comprises a flow channel layer, the flow channel layer forms a flow channel therebetween;

[0013] the flow channel has a width of greater than 200 microns;

[0014] the nozzle member comprises a nozzle layer, the nozzle layer forms a nozzle thereon;

[0015] the nozzle layer has a thickness of less than 150 microns;

[0016] the nozzle of the nozzle member has a diameter of greater than 20 microns;

[0017] the printhead has a single nozzle drop volume of greater than 40 picoliters and a printhead flow rate of greater than 60 microliters per second.

[0018] 2. The printhead of item 1, wherein the piezoelectric ceramic has a thickness of 70-300 microns; the electrode has a thickness of greater than 0.1 microns.

[0019] 3. The printhead of item 1 or 2, wherein the flow channel has a width of greater than 300 microns.

[0020] 4. The printhead of any one of items 1-3, wherein the nozzle of the nozzle member has a diameter of greater than 30 microns.

[0021] 5. The printhead of any one of items 1-4, wherein the printhead has a single nozzle drop volume of greater than 50 picoliters and a printhead flow rate of greater than 80 microliters per second.

[0022] 6. The printhead of any one of items 1-5, wherein the nozzle layer has a thickness of less than 100 microns.

[0023] 7. The printhead of any one of items 1-6, further comprising a circuit board card; the circuit board card provides more than 256 independent drive circuits.

[0024] 8. The printhead of any one of items 1-7, wherein the drive waveform has a voltage of greater than 80 volts and a pulse width of greater than 2 microseconds.

[0025] 9. A printing method comprising printing using the piezoelectric inkjet printhead of any one of items 1-8.

[0026] 10. A piezoelectric inkjet printer comprising the piezoelectric inkjet printhead of any one of claims 1-8.

[0027] Advantages

[0028] The piezoelectric inkjet printhead of large ink volume of the present application can spray droplets of appropriate size by controlling the thickness of the piezoelectric ceramic and the electrode, thereby improving the quality of the printed matter. In the present application, the diameter of the nozzle is set to an appropriate diameter, further enabling the droplets to be sprayed more uniformly onto the receiving material, thereby improving the quality of the printed matter. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 is a structural schematic diagram of the driving member of the present application;

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

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

[0032] The present application will be 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 described herein. On the contrary, 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 terms are used in the specification and claims to refer to particular components. It will be understood by those skilled in the art that different names can be used to refer to the same component. The specification and claims do not distinguish components based on the difference in names, but rather on the difference in functions. As mentioned throughout the specification and claims, "comprising" or "including" is an open term, which should be interpreted as "comprising but not limited to". The subsequent description is a preferred embodiment for implementing the present application, but the description is for the purpose of illustrating the general principles of the specification, and is not intended to limit the scope of the present application. The scope of protection of the present application is defined by the appended claims.

[0034] Reference Figure 1 The present application provides a piezoelectric inkjet printhead of large ink volume. The printhead comprises:

[0035] a driving member 1, a flow channel member 2, and a nozzle member 3;

[0036] In the present application, the whole of the driving member 1, the flow channel 21 member 2 and the nozzle 31 member 3 are planned, and each component is sized to a suitable size, so that the printing head in the present application has better quality when printing.

[0037] The driving member 1 is located above the flow channel 21 member 2, and the nozzle 31 frame is located below the flow channel 21 member 2. The ink of the printing head will flow in the flow channel 21 member 2, and then the driving member 1 will vibrate to generate driving force, so that the ink in the flow channel 21 member 2 is ejected from the nozzle 31 member 3.

[0038] The driving member 1 comprises a piezoelectric ceramic 11 and an electrode 12.

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

[0040] The electrode 12 is connected with a power supply. The power supply transmits electric energy 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 member 2 from the nozzle 31 member 3.

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

[0043] When the thickness of the piezoelectric ceramic 11 is small, the durability of the piezoelectric ceramic 11 will be reduced, and the service life of the piezoelectric ceramic 11 and the printing head will be shortened. When the thickness of the piezoelectric ceramic 11 increases, the amplitude of the vibration of the piezoelectric ceramic 11 will decrease, and the size of the ink droplets ejected under the vibration of the piezoelectric ceramic 11 will become smaller, which will affect the quality or speed of the printed matter. Therefore, in the present application, the thickness of the piezoelectric ceramic 11 is set to be between 50-400 microns, so that the piezoelectric ceramic 11 can improve the service life while ensuring the printing quality.

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

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

[0046] The electrode 12 is arranged on the piezoelectric ceramic 11 to supply power to the piezoelectric ceramic 11, so that the piezoelectric ceramic 11 vibrates. When the thickness of the electrode 12 is thin, the electrode 12 can withstand less electric energy, which leads to a decrease in the current or voltage that the electrode 12 can withstand, and thus the vibration amplitude of the piezoelectric ceramic 11 decreases, resulting in a decrease in the volume of the ejected liquid. When the thickness of the electrode 12 increases, the ejected ink droplets gradually increase. Therefore, in the present application, the thickness of the electrode 12 is set to be greater than 0.07 microns; the thickness of the piezoelectric ceramic 11 is within a suitable range, and the thickness of the electrode 12 is suitable, so that the print head can eject ink droplets of a suitable size.

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

[0048] The flow channel 21 component 2 comprises flow channel layers, and the flow channels 21 are formed between the flow channel layers.

[0049] The flow channel layers are below the electrode 12 layer, and the gaps between the flow channel layers for the ink to flow in are the flow channels 21. The piezoelectric ceramic 11 covers the top of the flow channels 21, so when the piezoelectric ceramic 11 vibrates, the ink droplets in the flow channels 21 can be vibrated out of the flow channels 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, 1000 microns.

[0052] The flow channel 21 is a channel for ink flow, and the flow channel 21 is located above the nozzle 31 component 3. The ink flows in the flow channel 21, and when the piezoelectric ceramic 11 vibrates, the ink in the flow channel 21 is extruded from the nozzle 31 component 3 to form ink droplets and be ejected.

[0053] In the field, generally, the width of the flow channel layer is consistent with the effective width of the piezoelectric ceramic 11, so when the width of the flow channel 21 is set to be wider, the width of the piezoelectric ceramic 11 located above it will also increase accordingly, which leads to the corresponding increase in the unit ink area of the nozzle 31 component 3 located below it, and further increases the flow of ink ejected by the nozzle 31 component 3. This is more helpful to improve the quality of the printed matter.

[0054] The nozzle 31 component 3 comprises a nozzle layer, and the nozzle layer is provided with nozzles 31 for ink droplets to pass through.

[0055] The nozzle layer is located below the flow channel 21, and a plurality of nozzles 31 are uniformly arranged on the nozzle layer. When the piezoelectric ceramic 11 vibrates, the ink in the flow channel 21 will be subjected to pressure, and then the ink will be extruded from the nozzles 31, at which time the ink will be ejected from the nozzles 31 in the form of ink droplets, and then fall on the substrate.

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

[0057] Specifically, the thickness of the nozzle 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, 50 microns.

[0058] The nozzle layer is located below the flow channel layer, and the nozzle layer is formed with nozzles 31 for ejecting ink droplets. The nozzle layer is fixedly connected with the flow channel layer, so that the hydraulic pressure caused by the ejection of ink droplets from the nozzles 31 is borne by the nozzle layer. Therefore, if the thickness of the nozzle layer is too small, the nozzle layer will be damaged.

[0059] On the other hand, since the nozzles 31 are formed in the nozzle layer, the depth of the nozzles 31 is equal to the thickness of the nozzle layer. When the thickness of the nozzle layer increases, the depth of the nozzles 31 also increases, which causes the resistance of the ink droplets passing through the nozzles 31 to increase, and thus the ink droplets are difficult to be ejected from the nozzles 31, and the volume of the ink droplets ejected from the nozzles 31 decreases.

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

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

[0062] Specifically, the diameter of the nozzles 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, 100 microns.

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

[0064] When the diameter of the nozzles 31 is small, the flow resistance of the structure increases, so that it is difficult for the ink to be ejected from the nozzles 31, and even under the extrusion of the piezoelectric ceramic 11, the ink droplets ejected from the nozzles 31 with a small diameter have a small volume, which greatly reduces the printing speed of the printhead.

[0065] Therefore, in the present application, the diameter of the nozzles 31 is set to be greater than 20 microns, so that the volume of the ink droplets ejected from the nozzles 31 is large, which improves the printing speed, and improves the printing quality and the service life of the printhead.

[0066] The volume of the ink droplets ejected from the nozzles 31 is greater than 40 picoliters; preferably, the volume of the ink droplets ejected from each nozzle of the printhead is greater than 50 picoliters.

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

[0068] The ink droplet emitted from the single nozzle of the printhead is the ink droplet emitted from the single nozzle of the printhead.

[0069] When the volume of the ink droplet emitted from the nozzle 31 is small, the flow rate of the printhead and the nozzle 31 will also be reduced accordingly, which will reduce the printing speed and printing efficiency. On the other hand, when the volume of the ink droplet is small, in order to reduce the splashing of the ink droplet, it is necessary to maintain a small distance between the nozzle 31 and the substrate, which increases the occurrence of contact friction between the substrate and the printhead, which will cause wear and tear of the printhead and reduce the service life of the printhead.

[0070] Therefore, the volume of the ink droplet emitted from the nozzle 31 should be greater than 40 picoliter, and preferably the volume of the ink droplet is greater than 50 picoliter, so that the ink droplet is large, and the substrate can be quickly sprayed with enough ink droplets to improve the printing speed. At the same time, the large ink droplet can effectively improve the printing height, thereby reducing the possibility of wear and tear between the substrate and the printhead, and improving the service life of the printhead.

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

[0072] Specifically, the flow rate of the nozzle 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, 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, 150 microliters per second.

[0073] The flow rate of the nozzle refers to the volume of ink droplets sprayed by all the nozzles in a unit of time. The flow rate of the nozzle is closely related to the quality and printing speed of the printed matter. The greater the flow rate of the nozzle, the more ink is sprayed in a unit of time, and the higher the quality of the printed matter. Therefore, in order to improve the printing quality and make the printed matter clear and complete, sufficient ink droplets need to be sprayed onto the printed matter. When the flow rate of the nozzle increases, the quality of the printed matter also increases. When the flow rate of the nozzle is small, the quality of the printed matter is significantly reduced or the yield of the printed matter is reduced. For example, the printed matter is incomplete or blurred. On the other hand, when the flow rate of the nozzle is small, in order to improve the printing quality and make the ink droplets on the printed matter per unit area sufficient, the moving speed of the printhead needs to be reduced, which further slows down the printing speed and reduces the printing efficiency.

[0074] Therefore, the flow rate of the nozzle in the present application is greater than 60 microliters per second, and preferably greater than 80 microliters per second. The printhead in the present application can print high-quality printed matter while maintaining a suitable printing speed, thereby improving the printing quality and speed.

[0075] The printhead further comprises 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, 1600.

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

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

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

[0081] Pulse width generally refers to the period during which the pulse reaches its maximum value in the electronic field.

[0082] The generated drive waveform has a voltage greater than 80 volts and a pulse width greater than 2 microseconds.

[0083] The power supply transmits electrical energy to the electrode 12 in the form of a voltage greater than 80 volts and a pulse width greater than 2 microseconds after passing through the circuit board card.

[0084] Specifically, the voltage of the drive 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, 150 volts.

[0085] When the voltage of the drive waveform increases, the voltage applied to the piezoelectric ceramic 11 also increases accordingly, which in turn increases the vibration amplitude of the piezoelectric ceramic 11, and further, the volume of the ink droplets ejected by the piezoelectric ceramic 11 also increases accordingly.

[0086] Therefore, in this application, the voltage of the drive waveform is set to be greater than 80 volts, which in turn makes 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, 50 microseconds.

[0088] When the driving pulse width increases, the duration of the piezoelectric ceramic 11 receiving the maximum voltage becomes longer, which can increase the vibration amplitude of the piezoelectric ceramic 11, and thus increase the extrusion amplitude of the piezoelectric ceramic 11 on the flow channel 21. Therefore, when the ink droplet is ejected from the nozzle 31, the volume of the ink droplet also increases accordingly. In this application, the pulse width is set to be greater than 2 microseconds, so that the ink droplet ejected from the nozzle 31 also increases accordingly, so as to improve the printing quality and printing speed.

[0089] The application also provides a printing method, which comprises printing using the piezoelectric inkjet print head described above.

[0090] The application also provides a piezoelectric inkjet printer, which comprises the piezoelectric inkjet print head described above.

[0091] Example 1

[0092] The application provides a large-ink-volume inkjet print head, the volume of the ink droplet ejected from 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 shown in Figure 2 .

[0093] In the print head, the sizes of the various components are as follows.

[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 microns;

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

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

[0098] In this application, the various parameters of the print head are adjusted for printing, and the printing conditions are recorded.

[0099] In the present application, the thickness of piezoelectric ceramic 11, electrode 12 and ejection orifice layer, and the printing head is manufactured in a predetermined size, and then the use effect of the printing head is recorded.

[0100] Example 2

[0101] In this example, the print head single hole (i.e. ejection orifice) emits different volume of ink droplets, and the print quality of the print file is recorded.

[0102] The different ink droplet sizes and the corresponding print file quality are recorded in the following table.

[0103] Table 1

[0104] Drop size / pico liter Print quality Scheme 1 20 Poor Scheme 2 30 Poor Scheme 3 40 Fair Scheme 4 50 Good Scheme 5 60 Good Scheme 6 70 Good Scheme 7 80 Very good

[0105] When the print quality of the print file is determined, it can be summarized as follows:

[0106] The figure is complete, no missing, clear and not blurred, no fly point, defined as very good;

[0107] The figure is complete, no missing, the figure edge has sawtooth, a small amount of fly point, defined as good;

[0108] The figure has missing or a small amount of missing, edge ghosting, fly ink or a large amount of fly ink, defined as poor.

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

[0110] Specifically: the known printing frequency is 20KHz; 1200K*1024 ink droplets are printed at a time (print 1 minute), and then the total number of ink droplets is divided to obtain the size of a single ink droplet.

[0111] Therefore, the average value of the size of the ink droplets is calculated in the present application.

[0112] The size of the ink droplets is measured using the above method, the total size of a plurality of ink droplets is measured, and the size of a single ink droplet is calculated. The difficulty of measuring smaller volume ink droplets is reduced, and the measurement of the size of the ink droplets is more accurate. The deviation of the size of the ink droplets detected by the above method is ≤10%; high precision ink droplet size data is obtained.

[0113] As can be seen from Example 2, although the volume of the ink droplets is 40 picoliters, the printing effect is still poor, but compared with smaller volume ink droplets, the printing effect has been improved. And when the ink droplet is greater than 50 picoliters, the printing effect changes to good. The large ink droplets ejected during printing realize large ink volume ejection of the printing head, at this time, good printing effect is achieved.

[0114] As can be seen in Example 2, as the drop volume increases, the quality of the printed product improves. The printhead flow rate also increases accordingly.

[0115] Example 3

[0116] In this example, the use of the printhead at different printhead flow rates is recorded by controlling the printhead flow rate at different amounts.

[0117] Table 2

[0118]

[0119] The printhead printing amount refers to the amount of ink that the printhead sprays on the substrate per unit time.

[0120] In printing, in order to ensure the printing quality, sufficient ink is printed on the unit area of the substrate, so that the printed document is more complete, has no missing, is clear and not blurred, has no flying points, and has very good effects.

[0121] As can be seen from this example, in actual application, when printing the same volume of ink on the substrate, the larger the drop and the larger the printhead flow rate, the faster the printing speed. On the other hand, the larger printhead flow rate and larger drop volume make the effective printing height of the printhead (the height from the printing substrate) higher; this means that the printhead is less likely to rub against the substrate, further increasing the service life of the printhead.

[0122] When the printhead sprays sufficient ink on the unit area of the substrate, the smaller the drop, the flow rate of the drop needs to be increased or the printing speed needs to be reduced. Spraying larger drops can increase the printing speed, and also increase the printing height, increase the distance between the substrate and the printhead, thereby reducing the wear of the substrate on the printhead, and further increasing the service life of the printhead.

[0123] Example 4

[0124] In this example, by setting different thicknesses of piezoelectric ceramic 11, and supplemented by two different thicknesses of electrode 12, the other component sizes are the same as the data in Example 1, and the relationship between the piezoelectric ceramic 11 and the drop size is calculated, and the drop size under different thicknesses of piezoelectric ceramic 11 is recorded.

[0125] Table 3

[0126]

[0127]

[0128] In the present application, the piezoelectric ceramic 11 is manufactured by a thinning polishing method, and the machining accuracy is ±2μm; therefore by controlling the machining accuracy, a printhead of piezoelectric ceramic 11 of different thicknesses can be manufactured.

[0129] The electrode 12 is manufactured by a deposition method, including sputtering, evaporation and plating, etc., during manufacture, and the machining accuracy of the electrode 12 is ±5nm; during deposition of the electrode 12, the manufacturing process can be controlled to manufacture electrodes 12 of different thicknesses on the printhead.

[0130] In this embodiment, by setting the piezoelectric ceramic 11 to different thicknesses, and setting the electrode 12 to two different thicknesses, it can be seen that the thinner the piezoelectric ceramic 11, the larger the ink droplet that can be generated.

[0131] However, the thickness of the piezoelectric ceramic 11 in the present application is already extremely small, so 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 reduced, further increasing the use cost of the printhead.

[0132] The thicker the thickness of the electrode 12, the larger the ink droplet generated. Therefore, the printhead in the present application sets a reasonable thickness of the piezoelectric ceramic 11 and the electrode 12, so that the printhead can print high-quality printed matter, and at the same time, the service life of the printhead can be improved.

[0133] Embodiment 5

[0134] In this embodiment, by setting the electrode 12 of different thicknesses on the piezoelectric ceramic 11, the relationship between the thickness of the electrode 12 and the size of the ink droplet is calculated, and the sizes of the ink droplets under different thicknesses of the electrode 12 are recorded, while the sizes of the other components are the same as in Embodiment 1.

[0135] Table 4

[0136]

[0137]

[0138] In this embodiment, data of two small thickness electrodes 12 are added. When the thickness of the electrode 12 is small, even if the thickness of the piezoelectric ceramic 11 is greatly reduced, it is difficult to increase the volume of the liquid droplet, so that the volume of the ink droplet is greater than 40 or 50 picoliters. Further, when the thickness of the piezoelectric ceramic 11 is reduced, the service life of the piezoelectric ceramic 11 will be greatly reduced. And the thinner electrode 12 is prone to overload and failure. Therefore, the thickness of the electrode 12 is set to be greater than 0.07 microns, preferably the thickness of the electrode 12 is greater than 0.1 microns.

[0139] Example 6

[0140] In this example, by setting the flow channel 21 of different width, other component sizes are the same as the data in Example 1, while recording the flow rate of the nozzle at different widths of the flow channel 21.

[0141] Table 5

[0142]

[0143]

[0144] As can be seen from this example, when the width of the flow channel 21 is greater, the flow rate of the nozzle and the volume of the ink droplet will also increase accordingly.

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

[0146] Wherein, the single nozzle flow rate = the volume of the emitted ink droplet * the emission frequency.

[0147] For example: the nozzle nozzle number = 1024; the volume of the emitted ink droplet = 80 picoliters; the emission frequency = 20KHz; then the flow rate of the nozzle = 80 picoliters * 20KHz * 1024 = 1638 microliters / second.

[0148] The deviation of the flow rate calculated by the above method is generally within ≤10%. It has very high measurement accuracy.

[0149] In the art, generally, the piezoelectric ceramic 11 is located directly above the flow channel 21 to seal the flow channel 21, so the width of the flow channel layer is equal to or close to the width of the piezoelectric ceramic 11. When the width of the flow channel 21 increases, the width of the piezoelectric ceramic 11 also increases accordingly. Further, the ink droplets ejected from the nozzle 31 will also increase under the action of the larger flow channel 21 and the larger piezoelectric ceramic 11.

[0150] On the other hand, when the width of the flow channel 21 increases, the corresponding unit area of the flow channel 21 above each nozzle 31 also increases accordingly. When the piezoelectric ceramic 11 vibrates, it will squeeze a larger amount of ink from the nozzle 31, thus increasing the droplet ejected from the nozzle 31.

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

[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. So that the ink droplets ejected by the print head have sufficient size. At the same time, the flow rate of the nozzle of the print head is controlled within a suitable range, increasing the printing speed of the print head.

[0153] Example 7

[0154] In this example, the diameter of the orifice 31 in the orifice member 3 is set to different sizes while the orifice layer thickness is kept constant, and the other component sizes are the same as in Example 1. The ink droplet size under different orifice 31 diameters is recorded.

[0155] Table 6

[0156] Nozzle diameter / micron Drop size / pico liter Scheme 1 10 5 Scheme 2 15 10 Scheme 3 20 20 Scheme 4 40 80 Scheme 5 60 90 Scheme 6 80 150 Scheme 7 100 200

[0157] As can be seen from this example, when the diameter of the orifice 31 is increased, the size of the ink droplet is also increased accordingly. However, when the diameter of the orifice 31 is too large, liquid leakage is likely to occur.

[0158] Example 8

[0159] In this example, the orifice layer is set to different thicknesses, and two different sizes of the orifice 31 are set for comparison, and the other component sizes are the same as in Example 1. The ink droplet size under different orifice layer thicknesses is recorded.

[0160] Table 7

[0161]

[0162]

[0163] As can be seen from this example, when the thickness of the orifice layer is increased, the ink droplet produced is correspondingly decreased. This is also applicable when the diameter of the orifice 31 is different.

[0164] However, when the thickness of the orifice layer is thick, even if the diameter of the orifice 31 is increased, the difference between the ink droplets produced is small. Therefore, when a thick orifice layer is used, a larger diameter of the orifice 31 is required to produce ink droplets of similar volume compared to the conventional.

[0165] Therefore, the thickness of the orifice layer is limited to less than 100 microns in this application. Within this range, the diameter of the orifice 31 and the size of the ink droplet are approximately linear. It is easier to control the volume of the ink droplet during design and manufacturing.

[0166] However, a thin orifice layer increases the manufacturing cost, shortens the service life, and causes the inkjet head to be more easily damaged. Therefore, the person skilled in the art can choose an orifice layer that is not too thin according to the actual situation.

[0167] Example 9

[0168] In this embodiment, the effect of the number of independent circuits on the drop size or the printhead flow rate is tested by setting different numbers of independent circuits. The other component sizes are the same as in Example 1, and the drop size or the printhead flow rate is recorded under different numbers of independent circuits.

[0169] Table 8

[0170] Number of independent circuits Printhead flow / microliter per second Scheme 1 150 120 Scheme 2 200 160 Scheme 3 250 200 Scheme 4 256 204.8 Scheme 5 300 240 Scheme 6 350 280

[0171] As can be seen from this embodiment, when the number of independent circuits is greater, the printhead flow rate also increases accordingly. Moreover, as the number of independent circuits increases, the printhead flow rate and the number of independent circuits are in a linear relationship.

[0172] Example 10

[0173] In this embodiment, the relationship between the voltage of the drive waveform of the circuit board card and the printhead flow rate or the drop size is calculated by controlling the voltage of the drive waveform of the circuit board card at different values, and the other component sizes are the same as in Example 1, and the drop size or the printhead flow rate is recorded under different drive waveform voltages.

[0174] Voltage of drive waveform / volt Pulse width Drop size / pico liter Scheme 1 40 5 0 Scheme 2 50 5 30 Scheme 3 70 5 40 Scheme 4 80 5 50 Scheme 5 90 5 60 Scheme 6 100 5 80 Scheme 7 150 5 100

[0175] As can be seen from this embodiment, the greater the drive waveform voltage, the greater the drop volume. Moreover, when the voltage of the drive waveform is small, the printhead cannot eject drops and thus the drop volume cannot be measured. Therefore, in this application, the voltage of the drive waveform is set to be greater than 80 volts so that drops of sufficient volume can be ejected.

[0176] Example 11

[0177] In this embodiment, the relationship between the pulse width of the circuit board card and the printhead flow rate or the drop size is calculated by controlling the pulse width of the circuit board card at different values while keeping the drive waveform voltage unchanged, and the other component sizes are the same as in Example 1, and the drop size or the printhead flow rate is recorded under different pulse widths.

[0178]

[0179]

[0180] As can be seen from the embodiment, when the pulse width is increased, the size of the ink droplet generated is also increased. When the pulse width is small, the volume of the ink droplet ejected is small, and in the case of small pulse width, even if the voltage is greatly increased, it is difficult to make the ink droplet ejected greater than 50 picoliters. In the case of greatly increased voltage, the print head is more dangerous in use, and when the voltage is too high, the internal parts of the print head are damaged. The use of the print head is more dangerous. When the pulse width is increased to a large range, the increase in the volume of the ink droplet ejected is already very small. Therefore, when the pulse width is increased to a large range, the influence of the pulse width on the volume of the ink droplet is also reduced.

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

[0182] The specific embodiment is only an explanation of the application, and is not a limitation of the application. Those skilled in the art can make modifications to the embodiment without creative contribution after reading the specification, as long as the modifications are within the scope of the claims of the application and are protected by the Patent Law.

Claims

1. A piezoelectric inkjet printhead with high ink volume, wherein, The printhead includes: Drive components, flow channel components, nozzle components; The driving component includes piezoelectric ceramic and electrodes. The thickness of the piezoelectric ceramic is 50–400 micrometers; the thickness of the electrode is greater than 0.07 micrometers. 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 micrometers; The nozzle component includes a nozzle layer on which nozzles are formed; The thickness of the nozzle layer is less than 150 micrometers; The diameter of the nozzle of the nozzle component is greater than 20 micrometers; The printhead emits ink droplets with a single orifice volume greater than 40 picoliters and a flow rate greater than 60 microliters per second.

2. The printhead according to claim 1, wherein the thickness of the piezoelectric ceramic is 70-300 micrometers; and the thickness of the electrode is greater than 0.1 micrometers.

3. The printhead according to claim 1 or 2, wherein the width of the flow channel is greater than 300 micrometers.

4. The printhead according to any one of claims 1 to 3, wherein the nozzle diameter of the nozzle component is greater than 30 micrometers.

5. The printhead according to any one of claims 1 to 4, wherein the volume of ink droplets emitted from a single nozzle is greater than 50 picoliters and the printhead flow rate is greater than 80 microliters per second.

6. The printhead according to any one of claims 1 to 5, wherein the thickness of the nozzle layer is less than 100 micrometers.

7. The printhead according to any one of claims 1 to 6, wherein the printhead further comprises a circuit board; the circuit board provides more than 256 independent drive circuits.

8. The printhead according to any one of claims 1 to 7, wherein the voltage of the driving waveform is greater than 80 volts and the pulse width is greater than 2 microseconds.

9. A printing method comprising printing using a piezoelectric inkjet printhead as described in any one of claims 1 to 8.

10. A piezoelectric inkjet printer comprising the piezoelectric inkjet printhead according to any one of claims 1 to 8.

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