Electric field assisted inkjet printing device

Abstract

The present invention relates to the field of biological 3D printing technology, specifically, an electric field assisted inkjet printing device, comprising a three-dimensional moving mechanism, a fine-tuning device, a print head, a droplet charging element and an electric field generating component, wherein the three-dimensional moving mechanism is provided with a movable support plate, the support plate is provided with an insulating bottom plate, the fine-tuning device comprises a fine-tuning mechanism and a height adjustment plate driven and moved by the fine-tuning mechanism, and the height adjustment plate is arranged above the insulating bottom plate, a droplet charging element is arranged on the lower side of the print head, and the print head and the droplet charging element can be adjustably mounted on the height adjustment plate, and the electric field generating component forms a droplet deceleration electric field between the droplet charging element and the insulating bottom plate, and the droplets output by the print head are first charged by the droplet charging element when falling, and then fall into the droplet deceleration electric field. The present invention can effectively reduce the occurrence of splashing, improve the cell survival rate, and ensure the resolution effect of the final printing.

Description

Technical Field

[0001] The present invention relates to the technical field of biological 3D printing, in particular to an electric field assisted inkjet printing device. Background Art

[0002] Bio-3D printing is a new tissue engineering technology that combines multiple disciplines on the basis of additive manufacturing technology. The ultimate goal of this technology is to achieve directional printing of organs to meet the transplant needs of clinical patients.

[0003] Compared with traditional xenogeneic organ transplantation treatment, since biological 3D printing uses tissue cells separated from the patient as materials to form tissue organs with specific structures, it has advantages such as lower immune rejection reactions.

[0004] At present, biological 3D printing technology mainly includes several printing methods such as extrusion, laser direct writing, inkjet and photocuring. Among them, inkjet printing has always received widespread attention in the field of biological 3D printing due to its high printing resolution and printed cell survival rate.

[0005] The principle of inkjet printing is to use the piezoelectric unit to deform or heat and vaporize to turn the bio-ink into droplets, and then the droplets are stacked layer by layer to form a three-dimensional structure. However, due to the formation mechanism of droplets, the droplets are ejected from the print head at a very fast speed. When the droplets are sprayed onto the bottom plate, splashing will occur, which greatly reduces the printing accuracy. At the same time, the shear stress generated during the rapid falling impact will also damage the cells loaded in the droplets, thereby reducing the survival rate of the cells. Summary of the invention

[0006] The purpose of the present invention is to provide an electric field-assisted inkjet printing device, which can effectively reduce the occurrence of splashing, while reducing the shear stress on the droplets during impact with the base plate, thereby improving the cell survival rate. The present invention ensures that the final printing resolution and survival rate achieve the optimal effect by controlling parameters such as the electric field distance, electric field strength, droplet charge, and initial spray droplet size.

[0007] The objective of the present invention is achieved through the following technical solutions:

[0008] An electric field-assisted inkjet printing device comprises a three-dimensional moving mechanism, a fine-tuning device, a print head, a droplet charging element and an electric field generating assembly, wherein the three-dimensional moving mechanism is provided with a movable support plate, the support plate is provided with an insulating bottom plate, the fine-tuning device comprises a fine-tuning mechanism and a height adjustment plate driven to move by the fine-tuning mechanism, and the height adjustment plate is arranged above the insulating bottom plate, a droplet charging element is arranged on the lower side of the print head, and the print head and the droplet charging element can be adjustably mounted on the height adjustment plate, the electric field generating assembly forms a droplet deceleration electric field between the droplet charging element and the insulating bottom plate, and the droplets output by the print head are first charged by the droplet charging element when falling, and then fall into the droplet deceleration electric field.

[0009] The electric field generating assembly includes a positive plate and a negative plate with adjustable spacing, and the negative plate is arranged below the positive plate. The positive plate and the negative plate are respectively connected to the power supply system through lines, and the positive plate and the negative plate are both provided with through holes for droplets to pass through.

[0010] The area of ​​the negative electrode plate is larger than that of the positive electrode plate, and the through holes on the negative electrode plate are larger than the through holes on the positive electrode plate.

[0011] The droplet charging element is a charging ring, and the print head, the charging ring, the positive electrode plate and the negative electrode plate are adjustable from top to bottom on the height adjustment plate.

[0012] The droplet charging element is a charging ring, and the print head, the charging ring, and the positive electrode plate are all adjustably mounted on the height adjustment plate from top to bottom, and the negative electrode plate is arranged on the insulating bottom plate.

[0013] The positive electrode plate is a droplet charging element, and the print head, the positive electrode plate, and the negative electrode plate can be adjustably mounted on the height adjustment plate.

[0014] The positive electrode plate is a droplet charging element, and the print head and the positive electrode plate can be adjustably mounted on the height adjustment plate, and the negative electrode plate is arranged on the insulating bottom plate.

[0015] The insulating bottom plate is provided with a notch, the negative electrode plate is embedded in the notch, and one side of the insulating bottom plate is provided with a wire through hole.

[0016] The three-dimensional moving mechanism includes a base, an X-direction moving seat, a Y-direction moving seat and a support plate, wherein the base is provided with an X-direction driving assembly, the X-direction moving seat is slidably connected to the base and is driven to move along the X-direction by the X-direction driving assembly, the X-direction moving seat is provided with a Y-direction driving assembly, the Y-direction moving seat is slidably connected to the X-direction moving seat and is driven to move along the Y-direction by the Y-direction driving assembly, the Y-direction moving seat is provided with a Z-direction lifting assembly, and the support plate is driven to lift and lower along the Z-direction by the Z-direction lifting assembly.

[0017] The fine-tuning mechanism comprises a fine-tuning base plate, a Y-direction moving platform, an X-direction moving platform and a Z-direction moving platform, wherein a Y-direction fine-tuning component is arranged on the fine-tuning base plate, the Y-direction moving platform is slidably connected with the fine-tuning base plate and is driven to move along the Y direction by the Y-direction fine-tuning component, an X-direction fine-tuning component is arranged on the Y-direction moving platform, the X-direction moving platform is slidably connected with the Y-direction moving platform and is driven to move along the X direction by the X-direction fine-tuning component, a Z-direction fine-tuning component is arranged on the X-direction moving platform, and the Z-direction moving platform is driven to rise and fall along the Z direction by the Z-direction fine-tuning component.

[0018] The advantages and positive effects of the present invention are:

[0019] 1. The present invention forms a droplet deceleration electric field between the droplet charging element and the insulating base plate. When the droplets output by the print head fall, they are first charged by the droplet charging element, and then fall into the droplet deceleration electric field and are decelerated by the upward electric field force. After passing through the droplet deceleration electric field, the speed at which the droplets fall onto the insulating base plate will be greatly reduced, thereby effectively reducing the occurrence of splashing and improving the printing resolution. At the same time, since the speed at which the droplets fall onto the insulating base plate is reduced, the stress generated during the impact is also greatly reduced, the damage to the cells is reduced, and the cell survival rate is thereby improved.

[0020] 2. The present invention can calculate and control the upward acceleration of the droplets by controlling the distance between the positive and negative plates (i.e., the droplet deceleration electric field distance), the electric field strength, the droplet charge, the initial spray droplet size and other parameters, and then control the droplet falling speed, ultimately ensuring that the printing resolution and survival rate achieve the optimal effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a schematic structural diagram of an embodiment of the present invention,

[0022] Figure 2 for Figure 1 Schematic diagram of the height adjustment plate structure,

[0023] Figure 3 for Figure 1 Schematic diagram of the mounting plate structure in

[0024] Figure 4 is a schematic structural diagram of another embodiment of the present invention,

[0025] Figure 5 for Figure 4 Schematic diagram of the insulating base plate structure,

[0026] Figure 6 FIG. 1 is a structural diagram of another embodiment of the present invention.

[0027] Figure 7 for Figure 1 Schematic diagram of the three-dimensional mobile mechanism structure,

[0028] Figure 8 for Figure 1 Schematic diagram of the fine-tuning mechanism structure.

[0029] Among them, 1 is a connecting plate, 2 is a height adjustment plate, 201 is an adjustment slot, 3 is a print head, 4 is a charging ring, 5 is a positive plate, 6 is a negative plate, 7 is an insulating bottom plate, 701 is a notch, 702 is a wire through hole, 8 is a three-dimensional moving mechanism, 801 is a base, 802 is an X-axis drive component 802, 803 is an X-axis moving seat, 804 is a Y-axis drive component, 805 is a Y-axis moving seat, 806 is a Z-axis lifting scissors, 807 is a Z-axis motor, and 808 is a Z-axis 809 is the Z-axis driving screw, 810 is the guide rod, 811 is the support plate, 812 is the mounting base plate, 9 is the fine-tuning mechanism, 901 is the fine-tuning base plate, 902 is the Y-axis fine-tuning assembly, 903 is the Y-axis moving table, 904 is the X-axis fine-tuning assembly, 905 is the X-axis moving table, 906 is the Z-axis fine-tuning assembly, 907 is the Z-axis moving table, 10 is the workbench, 11 is the support frame, 12 is the mounting plate, 121 is the dripping hole, and 122 is the mounting hole. DETAILED DESCRIPTION

[0030] The present invention will be further described below in conjunction with the accompanying drawings.

[0031] like Figures 1 to 8 As shown, the present invention includes a three-dimensional moving mechanism 8, a fine-tuning device, a print head 3, a droplet charging element and an electric field generating component, wherein the three-dimensional moving mechanism 8 is provided with a movable support plate 811, and the support plate 811 is provided with an insulating bottom plate 7, the fine-tuning device includes a fine-tuning mechanism 9 and a height adjustment plate 2 driven to move by the fine-tuning mechanism 9, and the height adjustment plate 2 is vertically arranged above the insulating bottom plate 7, the lower side of the print head 3 is provided with a droplet charging element, and the print head 3 and the droplet charging element can be adjustably mounted on the height adjustment plate 2, and the electric field generating component The component forms a droplet deceleration electric field between the droplet charging element and the insulating bottom plate 7. When the droplets output by the print head 3 fall, they are first charged by the droplet charging element, and then fall into the droplet deceleration electric field and are decelerated by the upward electric field force. After passing through the droplet deceleration electric field, the speed at which the droplets fall on the insulating bottom plate 7 will be greatly reduced, thereby effectively reducing the occurrence of splashing and improving the printing resolution. At the same time, since the speed at which the droplets fall on the insulating bottom plate 7 is reduced, the stress generated during the impact is also greatly reduced, the damage to the cells is reduced, and the cell survival rate is thereby improved. The insulating bottom plate 7 can be made of insulating resin.

[0032] The electric field generating assembly includes a positive plate 5 and a negative plate 6 with adjustable spacing, and the negative plate 6 is arranged below the positive plate 5. The positive plate 5 and the negative plate 6 are both made of metal and are connected to the power supply system through lines, and the positive plate 5 and the negative plate 6 are both provided with through holes for droplets to pass through. The power supply system can achieve field intensity regulation of the high-voltage electric field formed between the positive plate 5 and the negative plate 6 by controlling the power supply amount. In addition, the droplet charging element is also connected to the power supply system, and the power supply system can also adjust the charge of the droplets by controlling the power supply amount. The present invention achieves the purpose of regulating the upward electric field force on the droplets by adjusting the electric field strength and the charge of the droplets, and finally achieves the effect of controlling the droplet speed. The power supply system, field intensity regulation, droplet charge regulation, etc. are all well-known technologies in the field.

[0033] In addition, the present invention simulates the uniformity of the electric field through MATLAB software, and analyzes the influence of the size of the electrode plate, the punching position, and the relative movement position of the two electrode plates on the uniformity of the electric field. It is concluded that the uniformity of the electric field is related to the size of the electrode plate and the position of the electrode plate through-holes. Therefore, in the actual design, the negative electrode plate 6 on the lower side will be much larger than the positive electrode plate 5 on the upper side, and the through-holes on the lower negative electrode plate 6 are also much larger than the through-holes on the upper positive electrode plate 5. In this way, the uniformity of the electric field is ensured by the electrode plate size design and the through-hole position and size design, thereby ensuring that the droplets can pass through each electrode plate smoothly during the falling movement, and at the same time, the printing position will not deviate.

[0034] like Figures 1 to 3 As shown, in one embodiment of the present invention, the droplet charging element is a separately arranged charging ring 4, which can be regarded as a parallel plate capacitor, which is powered by a high voltage power supply (power supply system). Initially, the uncharged droplet enters the copper charging ring with a potential difference between the upper and lower parts. Due to the presence of ions in the droplet, the charge migrates after entering the electric field, thereby charging the droplet. Figure 1 As shown, in this embodiment, the print head 3, the charging ring 4, the positive plate 5 and the negative plate 6 can be adjustably mounted on the height adjustment plate 2, as shown in FIG. Figure 2 As shown, the height adjustment plate 2 is provided with an adjustment slot 201. Figure 3As shown, one side of the mounting plate 12 for mounting the print head 3, the charging ring 4, the positive plate 5 and the negative plate 6 is provided with a mounting hole 122 corresponding to the adjustment groove 201. In addition, except for the mounting plate 12 of the print head 3, the other mounting plates 12 are provided with a dripping hole 121 for the droplets to pass through, so that the print head 3, the charging ring 4, the positive plate 5 and the negative plate 6 can adjust the height and the distance between each other according to actual needs, wherein the distance adjustment between the positive plate 5 and the negative plate 6 can realize the distance adjustment of the droplet deceleration electric field, so that the upward acceleration of the droplet can be controlled by the parameters such as the electric field strength, the charge of the droplet, and the size of the initial ejected droplet (controlled by the print head 3), thereby achieving the purpose of controlling the droplet falling speed. The present invention ensures that the resolution of the final print reaches the optimal effect by controlling these variables. The print head 3 is a well-known technology in the art.

[0035] like Figures 4-5 As shown, in another embodiment of the present invention, the droplet charging element is also a separately arranged charging ring 4, but the negative electrode plate 6 is arranged on the insulating bottom plate 7, and the distance between the negative electrode plate 6 and the positive electrode plate 5 is adjusted by the Z-direction movement freedom in the three-dimensional moving mechanism 8, as shown in FIG. Figure 5 As shown, in this embodiment, a recess 701 is provided in the middle of the insulating bottom plate 7, and the negative electrode plate 6 is embedded in the recess 701. A wire through hole 702 is provided on one side of the insulating bottom plate 7 for the connection line between the negative electrode plate 6 and the power supply system to pass through, and the droplets fall directly on the negative electrode plate 6 after falling.

[0036] And as Figure 6 As shown, in another embodiment of the present invention, the separately arranged charging ring 4 is omitted. In this embodiment, the positive electrode plate 5 is used as a droplet charging element. The positive electrode plate 5 has a certain thickness and can also form an upper and lower potential difference. The droplets are charged when passing through the positive electrode plate 5, and then fall into the droplet deceleration electric field. The negative electrode plate 6 can be arranged on the height adjustment plate 2 or on the insulating bottom plate 7.

[0037] like Figure 7 As shown, the three-dimensional moving mechanism 8 includes a base 801, an X-direction moving seat 803, a Y-direction moving seat 805 and a support plate 811, wherein the base 801 is provided with an X-direction driving assembly 802, the X-direction moving seat 803 is slidably connected to the base 801 and is driven to move along the X-direction by the X-direction driving assembly 802, the X-direction moving seat 803 is provided with a Y-direction driving assembly 804, the Y-direction moving seat 805 is slidably connected to the X-direction moving seat 803 and is driven to move along the Y-direction by the Y-direction driving assembly 804, the Y-direction moving seat 805 is provided with a mounting base plate 812, and the mounting base plate 812 is provided with a Z-direction lifting assembly, and the support plate 811 is installed on the Z-direction lifting assembly.

[0038] like Figure 7 As shown, the X-axis driving component 802 and the Y-axis driving component 804 have the same structure and both include a driving motor, a lead screw and a nut, wherein the lead screw is driven to rotate by the motor, the nut is sleeved on the lead screw and drives the corresponding moving seat to move, wherein the nut of the X-axis driving component 802 is fixedly connected to the X-axis moving seat 803, and the nut of the Y-axis driving component 804 is fixedly connected to the Y-axis moving seat 805.

[0039] like Figure 7 As shown, the Z-axis lifting assembly includes a Z-axis lifting scissors fork 806, a Z-axis motor 807, a Z-axis driving nut 808 and a Z-axis driving screw 809, wherein the lower end of the Z-axis lifting scissors fork 806 is fixedly connected to the mounting base plate 812, and the upper end is fixedly connected to the support plate 811, and the Z-axis driving screw 809 is driven to rotate by the Z-axis motor 807, and the Z-axis driving nut 808 is mounted on the Z-axis driving screw 809 and connected to any articulated shaft on the corresponding Z-axis lifting scissors fork 806, and the Z-axis driving nut 808 moves along the Z-axis driving screw 809, thereby driving the corresponding articulated shaft to move, so that the Z-axis lifting scissors fork 806 is lifted or lowered, and the Z-axis motor 807 is lifted and lowered during this process. In addition, Figure 7 As shown, guide rods 810 are provided on both sides of the Z-direction driving screw 809 and pass through each Z-direction driving nut 808. The guide rods 810 play a role in moving guides, and the rear ends of the guide rods 810 on both sides are connected to a connecting seat body, and the Z-direction motor 807 is installed on the connecting seat body.

[0040] like Figure 8 As shown, the fine-tuning mechanism 9 includes a fine-tuning base plate 901, a Y-direction moving table 903, an X-direction moving table 905 and a Z-direction moving table 907, wherein the fine-tuning base plate 901 is provided with a Y-direction fine-tuning component 902, the Y-direction moving table 903 is slidably connected to the fine-tuning base plate 901 and is driven to move along the Y direction by the Y-direction fine-tuning component 902, the Y-direction moving table 903 is provided with an X-direction fine-tuning component 904, the X-direction moving table 905 is slidably connected to the Y-direction moving table 903 and is driven to move along the X direction by the X-direction fine-tuning component 904, the X-direction moving table 905 is provided with a Z-direction fine-tuning component 906, and the Z-direction moving table 907 is driven to rise and fall along the Z direction by the Z-direction fine-tuning component 906.

[0041] like Figure 8 As shown, the Y-axis fine-tuning assembly 902 and the X-axis fine-tuning assembly 904 have the same structure, both including a fine-tuning knob, a knob screw and a knob nut, the knob screw is driven to rotate by the fine-tuning knob, the knob nut is mounted on the knob screw and connected to the corresponding moving platform, the knob screw rotates to drive the knob nut to move, and then drives the corresponding moving platform to move. The Y-axis fine-tuning assembly 902 and the X-axis fine-tuning assembly 904 are well-known technologies in the art.

[0042] like Figure 8 As shown, the Z-axis fine-tuning assembly 906 includes a Z-axis fine-tuning knob, a Z-axis gear and a Z-axis rack, the Z-axis gear is meshed with the Z-axis rack and driven to rotate by the Z-axis fine-tuning knob, and the movement of the Z-axis rack drives the Z-axis moving stage 907 to move up and down. The Z-axis fine-tuning assembly 906 is a well-known technology in the art.

[0043] like Figure 1 As shown, a connecting plate 1 is provided on the Z-axis moving platform 907 and is fixedly connected to the upper end of the height adjustment plate 2 .

[0044] like Figure 1 As shown, the three-dimensional moving mechanism 8 of the present invention is arranged on a workbench 10 , a support frame 11 is arranged on the workbench 10 , the fine-tuning mechanism 9 is arranged on the upper side of the support frame 11 , and the three-dimensional moving mechanism 8 is arranged inside the support frame 11 .

[0045] The working principle of the present invention is:

[0046] When the present invention is working, a droplet deceleration electric field is formed between the droplet charging element and the insulating base plate 7. When the droplets output by the print head 3 fall, they are first charged by the droplet charging element, and then fall into the droplet deceleration electric field and are decelerated by the upward electric field force. After passing through the droplet deceleration electric field, the speed at which the droplets fall on the insulating base plate 7 will be greatly reduced, thereby effectively reducing the occurrence of splashing and improving the printing resolution. At the same time, since the speed at which the droplets fall on the insulating base plate 7 is reduced, the stress generated during the collision is also greatly reduced, and the damage to the cells is reduced, thereby improving the cell survival rate. In addition, the present invention can calculate and control the upward acceleration of the droplets by controlling the distance between the positive plate 5 and the negative plate 6 (i.e., the droplet deceleration electric field distance), the electric field strength, the droplet charge, the initial spray droplet size and other parameters, thereby controlling the droplet falling speed. The present invention controls these variables to ensure that the resolution of the final print reaches the optimal effect. In addition, the present invention can further adjust the position of the print head 3 and other components through the fine-tuning mechanism 9 in the fine-tuning assembly. After the adjustment is completed, the print head 3 is fixed during printing, and the insulating bottom plate 7 is driven to move by the three-dimensional moving mechanism 8 to achieve layer-by-layer stacking of droplets. Figures 1 to 6 As shown, the present invention can select a suitable embodiment structure according to actual needs, and is more flexible to use.

Claims

1. An electric field assisted inkjet printing device, characterized in that: The invention comprises a three-dimensional moving mechanism (8), a fine adjustment device, a print head (3), a droplet charging element and an electric field generating component, wherein the three-dimensional moving mechanism (8) is provided with a movable support plate (811), the support plate (811) is provided with an insulating bottom plate (7), the fine adjustment device comprises a fine adjustment mechanism (9) and a height adjustment plate (2) driven to move by the fine adjustment mechanism (9), and the height adjustment plate (2) is arranged above the insulating bottom plate (7), a droplet charging element is arranged on the lower side of the print head (3), and the print head (3) and the droplet charging element are both adjustably mounted on the height adjustment plate (2), and the electric field generating component forms a droplet deceleration electric field between the droplet charging element and the insulating bottom plate (7), and when the droplets output by the print head (3) fall, they are first charged by the droplet charging element and then fall into the droplet deceleration electric field; The electric field generating assembly comprises a positive plate (5) and a negative plate (6) with adjustable spacing, wherein the negative plate (6) is arranged below the positive plate (5), the positive plate (5) and the negative plate (6) are respectively connected to a power supply system via lines, and through holes for liquid droplets to pass through are arranged on the positive plate (5) and the negative plate (6); The area of ​​the negative electrode plate (6) is larger than that of the positive electrode plate (5), and the through hole on the negative electrode plate (6) is larger than the through hole on the positive electrode plate (5); The droplet charging element is a charging ring (4), and the print head (3), the charging ring (4), the positive electrode plate (5) and the negative electrode plate (6) are all adjustable from top to bottom on the height adjustment plate (2).

2. The electric field assisted inkjet printing device according to claim 1, characterized in that: The three-dimensional moving mechanism (8) comprises a base (801), an X-direction moving seat (803), a Y-direction moving seat (805) and a support plate (811), wherein the base (801) is provided with an X-direction driving assembly (802), the X-direction moving seat (803) is slidably connected to the base (801) and is driven to move along the X-direction by the X-direction driving assembly (802), the X-direction moving seat (803) is provided with a Y-direction driving assembly (804), the Y-direction moving seat (805) is slidably connected to the X-direction moving seat (803) and is driven to move along the Y-direction by the Y-direction driving assembly (804), the Y-direction moving seat (805) is provided with a Z-direction lifting assembly, and the support plate (811) is driven to lift and lower along the Z-direction by the Z-direction lifting assembly.

3. The electric field assisted inkjet printing device according to claim 1, characterized in that: The fine adjustment mechanism (9) comprises a fine adjustment base plate (901), a Y-direction moving platform (903), an X-direction moving platform (905) and a Z-direction moving platform (907), wherein a Y-direction fine adjustment component (902) is provided on the fine adjustment base plate (901), the Y-direction moving platform (903) is slidably connected to the fine adjustment base plate (901) and is driven to move along the Y direction by the Y-direction fine adjustment component (902), an X-direction fine adjustment component (904) is provided on the Y-direction moving platform (903), the X-direction moving platform (905) is slidably connected to the Y-direction moving platform (903) and is driven to move along the X direction by the X-direction fine adjustment component (904), a Z-direction fine adjustment component (906) is provided on the X-direction moving platform (905), and the Z-direction moving platform (907) is driven to rise and fall along the Z direction by the Z-direction fine adjustment component (906).

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