WO2023056745A1

WO2023056745A1 - Inkjet printing head and printing device

Info

Publication number: WO2023056745A1
Application number: PCT/CN2022/091827
Authority: WO
Inventors: 吕高仁
Original assignee: 深圳市博思得科技发展有限公司
Priority date: 2021-10-09
Filing date: 2022-05-10
Publication date: 2023-04-13
Also published as: CN115958890A

Abstract

Provided are an inkjet printing head which is low in cost and not easy to block a nozzle, and a printing device comprising same. The inkjet printing head comprises a control unit (300) and at least one inkjet unit. The inkjet unit comprises a first ink bin (100) and at least one second ink bin (200). The first ink bin is used for accessing pressurized ink of an external ink supply system, and at least one opening (110) is provided on a wall surface of the first ink bin. The second ink bin is adjacent to the first ink bin, each second ink bin is communicated with the first ink bin by means of the opening, a nozzle (210) corresponding to the opening is formed in a wall surface of the second ink bin, and the second ink bin is further communicated with an ink recovery ink path (400). The control unit comprises a driving IC (310) mounted to the outer side of the first ink bin, a valve driver (320) electrically connected to the driving IC, and a valve (330) accommodated in the first ink bin and connected to the valve driver; and the valve blocks or opens the opening under the action of the valve driver.

Description

A kind of inkjet printing head and printing device

technical field

The invention relates to the technical field of inkjet printing, in particular to an inkjet printing head and a printing device with low cost and difficult nozzle clogging.

Background technique

The inkjet method of inkjet printing equipment is mainly divided into continuous inkjet (Continuous Inkjet) and drop on demand (Drop on Demand). The ink stream ejected by continuous inkjet is continuous and uninterrupted. Under the pressure of the ink supply system, the ink is continuously ejected through small nozzles and separated into ink droplets under the action of an oscillator. The control system selectively applies charge to the ink droplet according to the printing information, and then when the ink droplet passes through the deflection electric field, according to the charge amount of the ink droplet, under the action of the electric field, the ink droplet is deflected and ejected to the corresponding position on the surface of the substrate to form graphic information , while allowing unwanted ink droplets to go directly to the recycling unit.

The drop-on-demand inkjet method mainly includes two kinds of inkjet technologies: Thermal Bubble Jet and Piezoelectric Inkjet. The thermal bubble jet technology relies on the heat generated by the resistance to vaporize the ink near the nozzle of the print head, so that the ink is ejected, and the target image or text is printed on the substrate; the piezoelectric inkjet technology uses piezoelectric The mechanical deformation of the device generates pressure on the ink to complete the ink ejection process. Among them, piezoelectric inkjet technology does not need to heat the ink, which reduces the requirements for ink selection, and piezoelectric inkjet technology can more accurately control the size of ink droplets, and the printing quality is easier to control. Its adaptability to ink The range is wider than thermal inkjet printing technology. At present, inkjet printing equipment with piezoelectric inkjet printing head is widely used in industrial fields such as outdoor advertising inkjet printing, textile printing and dyeing, ceramic building materials, electronics and 3D printing for graphic printing. The mainstream choice for ink printheads.

technical problem

However, the traditional piezoelectric inkjet print head has high requirements on the performance of the piezoelectric device, resulting in higher cost of the piezoelectric inkjet print head, and the residual ink droplets at the nozzle of the inkjet print head are easy to solidify, resulting in The nozzles are clogged, requiring frequent cleaning or maintenance of the nozzles, which increases the maintenance cost of the equipment.

technical solution

Based on this, it is necessary to provide an inkjet print head and a printing device with low cost and no easy nozzle clogging for the technical problems of high performance requirements of components, high cost and easy ink droplet clogging at the nozzle.

An inkjet printing head, the inkjet printing head includes a control unit and at least one inkjet unit, the inkjet unit includes a first ink tank and at least one second ink tank, the first ink tank is used to access The pressurized ink of the external ink supply system, and the wall of the first ink tank is provided with at least one opening; the second ink tank is adjacent to the first ink tank, and each of the second ink tanks passes through The opening is in communication with the first ink tank, the wall of the second ink tank is provided with a nozzle corresponding to the opening, and the second ink tank is also in communication with the ink recovery path;

The control unit includes a driver IC installed outside the first ink tank, a valve driver electrically connected to the driver IC, and a valve accommodated in the first ink tank and connected to the valve driver, the valve The opening is blocked or opened under the action of the valve driver.

In one embodiment, the line connecting the opening and the corresponding nozzle is perpendicular to the wall of the first ink tank where the opening is located.

In one of the embodiments, the diameter of the opening is smaller than the diameter of the nozzle.

In one of the embodiments, the first ink tank is provided with a flexible membrane on the opposite side of the wall where the opening is located, and the valve is accommodated in the first ink tank and fixedly installed on the flexible membrane. Above, the valve driver is located outside the first ink tank and is fixedly connected to the flexible diaphragm; when the valve driver receives the electrical signal sent by the drive IC, it controls the flexible diaphragm to generate a displacement to open or close the valve.

In one of the embodiments, when the displacement of the valve is greater than or equal to a quarter of the diameter of the opening, the valve is opened.

In one of the embodiments, the ink recovery channel communicates with an external ink recovery system with negative pressure.

In one of the embodiments, an ink discharge groove is provided on the wall of the first ink tank at the edge of the opening.

In one of the embodiments, a nozzle plate is also provided, and the nozzles are opened on the nozzle plate and correspond to the openings.

In one of the embodiments, the inkjet printing head further includes an ink supply ink path, and the ink supply ink path is used to communicate with an external ink supply system and receive pressurized ink into the first ink tank, and the second ink tank The ink tank is located at the bottom of the first ink tank.

The present invention also discloses a printing device, which comprises the above-mentioned inkjet printing head.

Beneficial effect

In the inkjet print head and printing device implementing the present invention, the pressurized ink of the external ink supply system is connected to the first ink tank, and the power of ink drop ejection is provided by the pressurizing device of the external ink supply system. Compared with the existing piezoelectric inkjet print head, it has greater ejection power, and the ink drop ejection speed and ejection distance exceed the existing piezoelectric inkjet print head, which improves the print head and printing device. The performance of the valve is relatively low, and the leaked ink droplets can be recovered through the ink recovery channel with negative pressure, which avoids ink leakage at the nozzle, and the ink that leaks into the second ink tank through the opening The drops keep flowing under the negative pressure of the ink recovery path, which avoids the problem of nozzle clogging caused by ink drying or sedimentation; the reduction in valve sealing requirements also reduces the performance requirements of the valve driver, which is conducive to reducing the inkjet print head. production cost.

Description of drawings

Fig. 1 is the structural representation of inkjet printing head in an embodiment of the present invention;

Fig. 2 is a schematic diagram of a non-sealed structure in an embodiment of the present invention.

Embodiments of the present invention

In order to make the above objects, features and advantages of the present invention more comprehensible, specific implementations of the present invention will be described in detail below in conjunction with the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, the present invention can be implemented in many other ways different from those described here, and those skilled in the art can make similar improvements without departing from the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed below.

Please refer to Fig. 1, the present invention discloses an inkjet printing head with low cost and the nozzle 210 is not easily clogged. Ink and the traditional piezoelectric inkjet method have lower requirements for ink, and the inkjet pressure can be adjusted in a wide range under the condition of ensuring the normal inkjet, so that the inkjet speed and inkjet distance can be significantly improved. promote. In addition, the inkjet print head of the present invention has lower requirements on the sealing of the valve 330, and when the ink jet is stopped, the leaked ink droplets at the valve 330 can be recovered under negative pressure, avoiding ink leakage at the nozzle 210 phenomenon, and the leaked ink droplet keeps flowing under the action of negative pressure, avoiding the clogging problem of the nozzle 210 caused by the solidification of the ink droplet, and improving the performance of the inkjet print head.

Specifically, the inkjet print head includes a control unit 300 and at least one inkjet unit, the inkjet unit includes a first ink tank 100 and at least one second ink tank 200, and the first ink tank 100 is used to access an external ink supply system The pressurized ink, that is, the first ink tank 100 is a pressurized tank, and the pressure is greater than or equal to 200kPa. Its pressure comes from the ink supply system outside the printhead. The ink supply system outside the print head is pressurized by an electric air pump, and its pressure adjustment range is large, which can provide greater ink ejection power, and is also suitable for inks with greater viscosity and tension. In the case of greater ejection power, The rate of ink ejection and ink ejection distance are significantly improved, which helps to improve the ink ejection quality of the printing device. The wall of the first ink tank 100 is provided with at least one opening 110 , the opening 110 provides an ink drop flow channel, and the diameter of the opening 110 is less than 30um. The second ink tank 200 is adjacent to the first ink tank 100, and each second ink tank 200 communicates with the first ink tank 100 through an opening 110, and the wall of the second ink tank 200 is provided with a nozzle 210 corresponding to the opening 110 , so that the ink flowing out through an opening 110 can flow out from a nozzle 210 correspondingly, and the second ink tank 200 is also communicated with the ink recovery ink path 400. In this embodiment, the far end of the second ink tank 200 from the nozzle 210 Or the side of the second ink tank 200 communicates with the ink recovery ink path 400 .

In this embodiment, the ink recovery path 400 communicates with the ink recovery system with negative pressure applied outside the print head, and the negative pressure is transmitted to the second ink tank 200 through the ink recovery path 400, and the second ink tank 200 is actually a negative pressure tank , when the nozzle 210 stops ink ejection, the ink in the first ink tank 100 leaks into the second ink tank 200 through the opening 110, and the excess ink entering the second ink tank 200 is under the negative pressure of the ink recovery system Collection is performed through the ink recovery ink path 400 to prevent ink from leaking at the nozzle 210 . The control unit 300 includes a driver IC 310 installed on the outside of the first ink tank 100, a valve driver 320 electrically connected to the driver IC 310, and a valve 330 housed in the first ink tank 100 and connected to the valve driver 320. The valve 330 is connected to the valve driver 320. Blocking or opening the opening 110 under action to control whether the inkjet operation of the printing head is performed or not. The driver IC 310 is an IC chip, used to control the inkjet printing head to work.

It can be understood that the inkjet print head of this embodiment includes at least one first ink tank 100, and each first ink tank 100 is provided with one or more openings 110, and each first ink tank 100 passes through each opening. The hole 110 communicates with one or more second ink tanks 200, and only one nozzle 210 is opened on each second ink tank 200. The outflowing ink correspondingly enters a second ink tank 200 and is ejected through the nozzle 210 on the second ink tank 200 . In other words, the ink in each first ink tank 100 can be sprayed only through the nozzle 210 on one second ink tank 200 , or can be sprayed through the nozzles 210 on multiple second ink tanks 200 .

It should be noted that, in order to avoid the problem of ink leakage at the nozzle 210 when there is no need for ink ejection, the ink recovery ink path 400 communicates with an external ink recovery system formed with a negative pressure, and the negative pressure is directly transmitted to the The second ink tank 200, so that the ink at the nozzle 210 will not leak under the action of negative pressure. In most cases, the negative pressure is less than 50 mmH ₂ O, that is, the pressure difference between the ink recovery path 400 and the nozzle 210 is less than 50 mmH ₂ O, so as to improve the ink leakage problem of the print head.

In one embodiment, the inkjet print head further includes an ink supply ink path 500, the ink supply ink path 500 is used to communicate with an external ink supply system and to receive pressurized ink into the first ink tank 100, that is, the external ink supply The system supplies pressurized ink to the first ink tank 100 through the ink supply ink path 500, and the ink pressure is greater than or equal to 200kPa. The second ink tank 200 is located at the bottom of the first ink tank 100, the length of the second ink tank 200 is greater than the length of the first ink tank 100, and the second ink tank 200 is flush with the same end of the first ink tank 100, the first The vertical section of the ink tank 100 is a rectangular structure, and the vertical section of the second ink tank 200 is an inverted L-shaped structure as shown in FIG. part, the ink recovery ink channel 400 is connected to the vertical part and communicates with the inner cavity of the second ink tank 200 , the ink supply ink channel 500 is adjacent to the ink recovery ink channel 400 and communicates with the opening at the top of the first ink tank 100 . Of course, the first ink tank 100 can also be a part of the ink supply path 500 . The first ink tank 100 and the ink supply ink path 500 are in an inverted L-shaped structure as a whole. Similarly, the second ink tank 200 and the ink recovery ink path 400 are in an inverted L-shaped structure as a whole. The first ink tank 100 and the second ink tank 200 There is a partition board between them, and holes are opened on the partition board to form the opening 110 .

Further, the first ink tank 100 is provided with a flexible diaphragm 600 on the opposite side of the wall where the opening 110 is located, the valve 330 is housed in the first ink tank 100 and is fixedly installed on the flexible diaphragm 600, and the valve driver 320 is located on the first ink tank 100. The outside of the ink tank 100 is fixedly connected to the flexible membrane 600; when the valve driver 320 receives the electrical signal sent by the driver IC 310, it controls the displacement of the flexible membrane 600 so that the valve 330 is opened or closed. That is to say, the top plate of the first ink tank 100 is a flexible diaphragm 600, and the flexible diaphragm 600 is deformed or displaced under the control of the valve driver 320, so that the valve 330 moves vertically to block or open the valve. The opening 110 achieves the purpose of controlling the start and stop of the inkjet operation. When the drive IC 310 controls the valve driver 320 to open the valve 330, the pressurized ink in the first ink tank 100 is ejected from the opening 110 into the second ink tank 200 under the action of pressure, and under the action of the ejection pressure, the ink is ejected from the nozzle. 210 ejects the print head.

In this embodiment, the valve driver 320 is a piezoelectric device, and the valve 330 is opened or closed by controlling the voltage change at both ends of the piezoelectric device to generate a displacement. It should be noted that, in this embodiment, the direction in which the piezoelectric device drives the flexible diaphragm 600 and the valve 330 to move is perpendicular to the wall where the opening 110 on the first ink tank 100 is located, that is, perpendicular to the partition plate, so that the piezoelectric device The resistance to be overcome during the action is mainly the pressure and tension generated by the pressurized ink in the first ink tank 100 when the valve 330 is opened and closed. The ink pressure in the first ink tank 100 is greater than or equal to 200kPa, the hardness of ordinary PZT piezoelectric ceramics can reach above 250MPa, and the pressure and tension that the piezoelectric device can bear is related to the hardness and deformation of the material. The valve 330 can be opened or closed when the deformation of the valve driver 320 is greater than or equal to a quarter of the diameter of the opening 110 . In this embodiment, the diameter of the opening 110 is less than 30 um. It can be seen that the technical solution of the present invention does not have high requirements on the performance of the piezoelectric device of the valve driver 320, so that it is easy to manufacture and reduces the equipment cost.

The print head is also provided with a nozzle plate 700 , and the nozzles 210 are set on the nozzle plate 700 and correspond to the openings 110 . Specifically, the bottom of the second ink tank 200 is provided with a nozzle plate 700, the nozzle plate 700 is detachably connected to the body of the second ink tank 200, and the connection is designed to be sealed.

The line connecting the opening 110 and its corresponding nozzle 210 is perpendicular to the wall surface where the opening 110 is located on the first ink tank 100. It can also be understood that when the opening 110 and the nozzle 210 are both round holes, each opening 110 and The corresponding nozzles 210 are arranged concentrically so that the pressure of the ink ejected from the opening 110 directly acts on the nozzles 210 to ensure the inkjet effect. Further, the diameter of the opening 110 is smaller than that of the nozzle 210 , that is, the opening 110 is smaller than the nozzle 210 , so as to ensure that the pressure of the ink ejected from the opening 110 can be more concentrated on the range of the nozzle 210 .

In one embodiment, when the displacement of the valve 330 is greater than or equal to a quarter of the diameter of the opening 110 , the valve 330 is opened. For example, if the diameter of the opening 110 is set as d, when the displacement distance h≥d/4 of the valve 330 is opened, the valve 330 is fully opened to allow the ink to pass through, so that the displacement of the valve 330 is very small when opening/closing , the performance requirements of the valve driver 320 are not high. The valve 330 can also be an electrothermal microvalve or an electromagnetic microvalve. This embodiment actually also provides a "non-sealed structure", so that when the valve 330 is closed, a small amount of ink still enters the second ink tank 200, and this part of leaked ink keeps flowing under the negative pressure of the ink recovery ink path 400 , to prevent the second ink tank 200 and the ink at the nozzle 210 from drying or settling to cause clogging.

Please refer to FIG. 2 , the wall of the first ink tank 100 is provided with an ink discharge groove 800 on the edge of the opening 110 . Specifically, a plurality of ink discharge grooves 800 are uniformly arranged on the edge of the opening 110, and each ink discharge groove 800 is radially distributed with the center of the opening 110 as the center, and the projection of the valve 330 on the wall surface where the opening 110 is located falls into each In the area surrounded by the ink discharge groove 800, like this, when the valve 330 is closed, it avoids the occurrence of the problem that the ink is difficult to penetrate into the second ink tank 200 caused by the valve 330 blocking the ink discharge groove 800, thereby preventing the second ink tank from The ink at 200 and nozzle 210 is dry and blocked to ensure the reliability of inkjet. It should be noted that the dotted line part in FIG. 2 is a blocked part, which is only used to illustrate the positional relationship of each component, and does not limit the shape of the component.

In addition, the present invention also discloses a printing device, which includes the above-mentioned inkjet printing head, an ink supply system that provides ink ejection power for the inkjet printing head, and an ink supply system that communicates with the ink recovery ink path 400 and is used to provide negative Ink recovery system that presses to recover excess ink.

The inkjet printing head and the printing device implementing the present invention are connected to the pressurized ink of the external ink supply system in the first ink tank 100, the power of ink drop ejection is provided by the pressurizing device of the external ink supply system, and the inkjet pressure The adjustable range is large, compared with the existing piezoelectric inkjet print head, it has greater ejection power, and the ink droplet ejection speed and ejection distance exceed the existing piezoelectric inkjet print head, which improves the print head and printing ability. The performance of the device; the tightness requirements at the valve 330 are relatively low, and the leaked ink droplets can be recovered through the ink recovery ink path 400 with negative pressure, which avoids ink leakage at the nozzle 210 and leaks into the first nozzle through the opening 110 The ink droplets in the second ink tank 200 keep flowing under the negative pressure of the ink recovery ink path 400, which avoids the nozzle 210 clogging problem caused by ink drying or sedimentation; the reduction of the sealing requirements of the valve 330 also makes the performance requirements of the valve driver 320 The synchronous reduction is beneficial to reduce the production cost of the inkjet printing head.

The technical features of the above-mentioned embodiments can be combined arbitrarily. To make the description concise, all possible combinations of the technical features in the above-mentioned embodiments are not described. However, as long as there is no contradiction in the combination of these technical features, should be considered as within the scope of this specification.

The above-mentioned embodiments only express several implementation modes of the present invention, and the descriptions thereof are relatively specific and detailed, but should not be construed as limiting the patent scope of the invention. It should be pointed out that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent for the present invention should be based on the appended claims.

Claims

An inkjet printing head, characterized in that it includes a control unit (300) and at least one inkjet unit, the inkjet unit includes a first ink tank (100) and at least one second ink tank (200), the The first ink tank (100) is used to access pressurized ink from an external ink supply system, and the wall of the first ink tank (100) is provided with at least one opening (110); the second ink tank (200) ) is adjacent to the first ink tank (100), and each of the second ink tanks (200) communicates with the first ink tank (100) through an opening (110), the second Nozzles (210) corresponding to the openings (110) are provided on the wall of the ink tank (200), and the second ink tank (200) is also communicated with the ink recovery path (400);

The control unit (300) includes a driving IC (310) installed outside the first ink tank (100), a valve driver (320) electrically connected to the driving IC (310), and a valve driver (320) housed in the first ink tank (100). An ink tank (100) and a valve (330) connected to the valve driver (320), the valve (330) blocks or opens the opening (110) under the action of the valve driver (320).
The inkjet print head according to claim 1, characterized in that the line connecting the opening (110) and the corresponding nozzle (210) is perpendicular to the opening (110) on the first ink tank (100) ) on the wall.
The inkjet printing head according to claim 1, characterized in that the diameter of the opening (110) is smaller than the diameter of the nozzle (210).
The inkjet print head according to claim 1, characterized in that, the first ink tank (100) is provided with a flexible diaphragm (600) on the opposite side of the wall where the opening (110) is located, and the The valve (330) is accommodated in the first ink tank (100) and fixedly installed on the flexible diaphragm (600), and the valve driver (320) is located outside the first ink tank (100) and fixed connected to the flexible diaphragm (600); when the valve driver (320) receives the electrical signal sent by the drive IC (310), it controls the flexible diaphragm (600) to generate a displacement so that the valve (330) ON or OFF.
The inkjet printing head according to claim 1, wherein the valve (330) is opened when the displacement of the valve (330) is greater than or equal to a quarter of the diameter of the opening (110).
The inkjet print head according to claim 1, characterized in that, the ink recovery path (400) communicates with an external ink recovery system formed with a negative pressure.
The inkjet printing head according to claim 1, characterized in that, an ink discharge groove (800) is provided on a wall surface of the first ink tank (100) at an edge of the opening (110).
The inkjet print head according to claim 1, characterized in that a nozzle plate (700) is further provided, and the nozzles (210) are opened on the nozzle plate (700) and correspond to the openings (110) .
The inkjet print head according to claim 1, further comprising an ink supply ink path (500), the ink supply ink path (500) is used to communicate with an external ink supply system and supply the first ink The cartridge (100) receives pressurized ink.
A printing device, characterized by comprising the inkjet printing head described in any one of claims 1-9.