Method and system for cleaning an inkjet system

Abstract

The application provides a cleaning method and system of an inkjet system, and relates to the field of photovoltaic cell manufacturing. The cleaning method comprises the following steps: a first positive pressure is formed in a nozzle of the inkjet system, the first positive pressure is used to prevent ink from dripping from the nozzle, and an ink meniscus barrier is formed at the nozzle; in a state where the first positive pressure is maintained in the nozzle, a wiping member is controlled to be in contact with the nozzle and to move relative to the nozzle to wipe the nozzle. By forming a micro-positive pressure in the nozzle, the risk of the cleaning agent penetrating into the nozzle is reduced, and the risk of the cleaning agent contaminating the ink is reduced.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic cell manufacturing, and more particularly to a cleaning method and system for inkjet systems. Background Technology

[0002] In the manufacturing process of photovoltaic cells, an inkjet printing method is used to form a photoelectric sensing layer on the surface of the cell. After the inkjet system has been running for a period of time, the nozzles of the inkjet system need to be cleaned to maintain the high-precision printing capability of the inkjet system. The cleaning agents in the related cleaning system may contaminate the ink. Summary of the Invention

[0003] This invention provides a cleaning method and system for inkjet systems, which addresses the technical problem of how to reduce the risk of cleaning agents contaminating ink.

[0004] The first aspect of this invention provides a cleaning method for an inkjet system applied in a photovoltaic cell production system. The cleaning method includes: controlling a first positive pressure to be formed inside the nozzle of the inkjet system, the first positive pressure being used to prevent ink from dripping from the nozzle and to form an ink meniscus barrier at the nozzle; and, while maintaining the first positive pressure inside the nozzle, controlling a wiping member to contact the nozzle and moving the wiping member relative to the nozzle to wipe the nozzle.

[0005] In some embodiments, the first positive pressure is positively correlated with the surface tension of the ink and the cosine of the contact angle between the nozzle and the wiping element; the first positive pressure is negatively correlated with the nozzle orifice radius.

[0006] In some implementations, the first positive pressure is between 0.5 and 1 kPa.

[0007] In some embodiments, controlling the formation of a first positive pressure within the nozzle of the inkjet system includes: acquiring the movement speed of the wiping member and the distance between the wiping member and the nozzle; calculating the contact time point between the wiping member and the nozzle based on the movement speed and the distance; determining a time point before a preset duration of the contact time point as the positive pressure establishment time point; and controlling the formation of the first positive pressure within the nozzle of the inkjet system at the positive pressure establishment time point.

[0008] In some embodiments, after the wiping member contacts the nozzle and moves relative to the nozzle, the cleaning method further includes: in the state where the wiping member is separated from the nozzle, forming a second positive pressure in the nozzle and maintaining it for a preset duration to cause ink to be ejected from the nozzle, wherein the second positive pressure is greater than the first positive pressure.

[0009] In some embodiments, the step of forming a second positive pressure in the nozzle and maintaining it for a preset duration while the wiping member is separated from the nozzle includes: forming a second positive pressure in the nozzle and maintaining it for a preset duration after a preset time delay from the time point at which the wiping member is separated from the nozzle.

[0010] In some implementations, the second positive pressure is greater than 5 kPa, the preset duration is between 0.5 and 1 second, and the time delay is less than 100 milliseconds.

[0011] In some embodiments, after the wiping member contacts the nozzle and moves relative to the nozzle, the cleaning method further includes: controlling the formation of a negative pressure within the nozzle while the wiping member is separated from the nozzle.

[0012] In some embodiments, the inkjet system includes an ink reservoir for storing ink, the nozzle being in communication with the ink reservoir, and the cleaning method further includes: controlling the nozzle to isolate from the ink reservoir before a first positive pressure is formed within the nozzle of the inkjet system; and after controlling a wiping member to contact the nozzle and move the wiping member relative to the nozzle while maintaining the first positive pressure within the nozzle, the cleaning method further includes: controlling the nozzle to communicate with the ink reservoir.

[0013] A second aspect of the present invention provides a cleaning system for an inkjet system, the cleaning system comprising: a pressure control module for controlling the formation of a first positive pressure within the nozzle of the inkjet system, the first positive pressure being used to prevent ink from dripping from the nozzle and to form an ink meniscus barrier at the nozzle; and a motion control module for controlling a wiping member to contact the nozzle and move the wiping member relative to the nozzle while maintaining the first positive pressure within the nozzle, so as to wipe the nozzle.

[0014] This invention provides a cleaning method for an inkjet system. The cleaning method includes: controlling a first positive pressure to be formed inside the nozzle of the inkjet system, the first positive pressure being used to prevent ink from dripping from the nozzle and to form an ink meniscus barrier at the nozzle; maintaining the first positive pressure inside the nozzle, controlling a wiping member to contact the nozzle and moving the wiping member relative to the nozzle to wipe the nozzle. It can be understood that when the wiping member contacts the nozzle, the first positive pressure is maintained inside the nozzle, and the first positive pressure and the tension of the ink meniscus barrier jointly prevent the penetration of cleaning agent, thereby reducing the risk of cleaning agent contaminating the ink. Attached Figure Description

[0015] Figure 1 A schematic flowchart of a cleaning method for a first inkjet system provided in an embodiment of the present invention; Figure 2A schematic flowchart of a second inkjet system cleaning method provided in an embodiment of the present invention; Figure 3 A schematic flowchart of a third inkjet system cleaning method provided in an embodiment of the present invention; Figure 4 A schematic flowchart illustrating a fourth inkjet system cleaning method provided in an embodiment of the present invention; Figure 5 This is a schematic diagram of the system architecture of a cleaning system for an inkjet system provided in an embodiment of the present invention. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0017] The specific technical features described in the various embodiments in the detailed implementation can be combined in various ways without contradiction. For example, different implementation methods can be formed by combining different specific technical features. In order to avoid unnecessary repetition, the various possible combinations of the specific technical features in this invention will not be described separately.

[0018] It should also be noted that, in order to avoid obscuring the present invention with unnecessary details, only the structures and / or processing steps closely related to the present invention are shown in the accompanying drawings, while other details that are not closely related to the present invention are omitted.

[0019] Additionally, it should be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. In the following description, the terms "first," "second," etc., are used merely to distinguish different objects and do not indicate any similarity or connection between them. It should be understood that the directional descriptions such as "above," "below," "inside," and "outside" refer to the orientation under normal use conditions.

[0020] The following specific embodiment provides a cleaning method for an inkjet system used in photovoltaic cell production systems. This inkjet system requires significantly higher printing precision than ordinary printing systems, resulting in a small radial dimension of the inkjet nozzle. During the cleaning process, specifically when the wiping element cleans the nozzle, the cleaning agent in the wiping element may penetrate into the nozzle's interior under capillary action. This penetrating cleaning agent may cause ink jet deflection or even nozzle blockage, making it difficult for the inkjet system to meet the high precision requirements of photovoltaic cell production. Specifically, when the cleaning solvent comes into contact with the extremely sensitive cationic initiator system ink, a demulsification reaction occurs instantly, causing the resin to rapidly precipitate and form a high-viscosity, lard-like gel, leading to physical blockage or even scrapping of the extremely expensive printhead.

[0021] Furthermore, if the cleaning agent seeps into the ink reservoir along the ink supply line, contaminating the ink inside, the ink in the reservoir will be affected. Ink in different printing fields only requires stable coloring, while the photovoltaic cell manufacturing field has very high requirements for the stability of the printing ink composition and has a high cost. In order not to affect the printing quality of photovoltaic cells, it is necessary to discard an entire box of contaminated ink, resulting in significant losses.

[0022] The applicant, recognizing the unique requirements of photovoltaic cell production systems compared to general printing scenarios, conceived of a cleaning method for inkjet systems used in photovoltaic cell production. This method involves maintaining a slight positive pressure within the nozzle during contact between the wiping element and the nozzle. This positive pressure counteracts capillary action, reducing the risk of cleaning agent seeping into the nozzle. The following examples illustrate the process of this inkjet system cleaning method.

[0023] In some embodiments, please refer to Figure 1 , Figure 1 This is a schematic flowchart of a cleaning method for an inkjet system provided in an embodiment of the present invention, as shown below. Figure 1 As shown, the cleaning method includes: Step S101: Control the formation of a first positive pressure inside the nozzle of the inkjet system.

[0024] The first positive pressure is used to prevent ink from dripping from the nozzle and to form an ink meniscus barrier at the nozzle. This can be understood as forming a small first positive pressure inside the nozzle to resist capillary action when the wiping piece contacts the nozzle, reducing the risk of cleaning agent seeping into the nozzle. Moreover, this first positive pressure also needs to prevent ink from dripping from the nozzle, but rather to form an outward-convex ink meniscus barrier at the nozzle opening under the action of the ink's surface tension. This meniscus barrier can not only reduce ink consumption, but also further block the cleaning agent through the surface tension of the ink, thereby further reducing the risk of cleaning agent seeping into the nozzle.

[0025] Step S102: While maintaining a first positive pressure inside the nozzle, control the wiping element to contact the nozzle and make the wiping element move relative to the nozzle.

[0026] That is, the nozzle is cleaned by the relative movement of the wiping component and the nozzle, and during the contact between the wiping component and the nozzle, the cleaning agent is continuously prevented from penetrating into the nozzle by the first positive pressure and the ink meniscus barrier.

[0027] Optionally, the magnitude of the first pressure that prevents ink from dripping and forms an ink meniscus barrier is related to the surface tension of the ink, the contact angle between the nozzle and the wiping element, and the nozzle orifice radius. Specifically, the first positive pressure is positively correlated with the surface tension of the ink and the cosine value of the contact angle, and negatively correlated with the nozzle orifice radius.

[0028] Optionally, the formula for calculating the first pressure is: P1 = (2γcosθ) / R In the formula, P1 is the first pressure, γ is the surface tension of the ink, θ is the contact angle between the wiping element and the nozzle, and R is the nozzle orifice radius. Optionally, the first pressure is between 0.5 and 1 kPa.

[0029] This invention provides a cleaning method for an inkjet system. The cleaning method includes: controlling a first positive pressure to be formed inside the nozzle of the inkjet system, the first positive pressure being used to prevent ink from dripping from the nozzle and to form an ink meniscus barrier at the nozzle; maintaining the first positive pressure inside the nozzle, controlling a wiping member to contact the nozzle and moving the wiping member relative to the nozzle to wipe the nozzle. It can be understood that when the wiping member contacts the nozzle, the first positive pressure is maintained inside the nozzle, and the first positive pressure and the tension of the ink meniscus barrier jointly prevent the penetration of cleaning agent, thereby reducing the risk of cleaning agent contaminating the ink.

[0030] In some embodiments, please refer to Figure 2 , Figure 2 This is a flowchart illustrating a second inkjet system cleaning method provided in an embodiment of the present invention, based on... Figure 1 ,like Figure 2As shown, Figure 1 Step S101 includes: Step S201: Obtain the movement speed of the wiping component and the distance between the wiping component and the nozzle, and calculate the contact time point between the wiping component and the nozzle based on the movement speed and the distance.

[0031] This can be understood as estimating the time point at which the nozzle and the wiping component begin to make contact by using the relative positions of the wiping component and the nozzle's movement speed.

[0032] Step S202: Determine the time point before the preset contact time point as the positive pressure establishment time point, and control the formation of the first positive pressure in the nozzle of the inkjet system at the positive pressure establishment time point.

[0033] This can be understood as establishing positive pressure in advance before the expected point when the wiping element and the nozzle begin to contact. That is, taking into account the time required for positive pressure to be established, positive pressure is formed in advance before contact. When the wiping element and the nozzle come into contact, the first positive pressure has already been established, thus more reliably preventing the cleaning agent from seeping into the nozzle.

[0034] In some embodiments, such as Figure 3 As shown, Figure 3 This is a flowchart illustrating a third inkjet system cleaning method provided in an embodiment of the present invention, based on... Figure 1 ,like Figure 3 As shown, in Figure 1 Following step S102, the cleaning method further includes: Step S301: With the wiping element separated from the nozzle, a second positive pressure is formed inside the nozzle and maintained for a preset duration so that ink is ejected from the nozzle.

[0035] The second positive pressure is greater than the first positive pressure. This can be understood as follows: after the wiping device finishes wiping the nozzle, a short-term high positive pressure is formed inside the nozzle while the wiping device is separated from the nozzle. This causes a small amount of ink to be quickly separated from the nozzle. Through this flash spray-like method, the sprayed ink washes away any cleaning agent that may remain near the nozzle orifice, further reducing the risk of cleaning agent seeping into the nozzle.

[0036] Optionally, after a preset time delay at the point of separation between the wiping element and the nozzle, a second positive pressure is formed inside the nozzle and maintained for a preset duration. This can be understood as the second positive pressure starting to spray ink only after a certain time delay between the separation of the wiping element and the nozzle. This ensures that the inkjet rinsing only begins when the wiping element and the nozzle are sufficiently far apart, reducing the risk of ink being blocked by the wiping element during the inkjet rinsing process and the risk of ink being washed onto the surface of the wiping element, thereby improving the effectiveness of inkjet rinsing in removing residual cleaning agent.

[0037] Optionally, the second positive pressure is greater than 5 kPa, the preset duration is between 0.5 and 1 second, and the time delay is less than 100 milliseconds.

[0038] In some embodiments, Figure 1 Following step S102, the inkjet system cleaning method further includes: controlling the formation of negative pressure within the nozzle while the wiping element is separated from the nozzle. This can be understood as switching the positive pressure within the nozzle to negative pressure after wiping is complete and the wiping element is separated from the nozzle. This negative pressure pulls the convex ink meniscus barrier back into the nozzle, thereby reducing the likelihood of ink dripping, thus reducing ink consumption and the risk of dripping ink contaminating the work surface.

[0039] Optional, in Figure 3 Following step S301, the inkjet system cleaning method further includes: controlling the formation of negative pressure inside the nozzle while the wiping element is separated from the nozzle. This can be understood as follows: after using a short period of high positive pressure to perform high-pressure flash spraying on the nozzle, and flushing away any residual cleaning agent near the nozzle orifice with ink, negative pressure is then controlled inside the nozzle to further reduce the risk of residual cleaning agent being drawn in by this negative pressure.

[0040] In some embodiments, the inkjet system includes an ink reservoir for storing ink, and a nozzle is in communication with the ink reservoir. Ink in the ink reservoir can be supplied to the nozzle via an ink supply line, thereby enabling ink to be ejected from the nozzle. See also... Figure 4 , Figure 4 This is a flowchart illustrating the fourth inkjet system cleaning method provided in this embodiment of the invention, based on... Figure 1 ,like Figure 4 As shown, Figure 1 Prior to step S101, the cleaning method further includes: Step S401: Control the nozzle to isolate from the inkjet chamber.

[0041] This can be understood as follows: before cleaning the nozzles, the nozzles need to be isolated from the inkjet cartridge. This physically blocks the connection between the nozzles and the cartridge, preventing cleaning agents from seeping into the cartridge and reducing the risk of contaminating the entire cartridge. It should be noted that with the nozzles isolated from the cartridge, the ink supply lines connecting each nozzle form an internal circulation system or are open to the atmosphere. This creates a first or second positive pressure within the nozzles. Some ink remains in this internal circulation system. Under the first positive pressure, this ink forms an ink meniscus barrier; under the second positive pressure, it can also be ejected from the nozzles to flush them.

[0042] exist Figure 1 Following step S102, the cleaning method further includes: Step S402: Connect the nozzle to the ink reservoir.

[0043] This can be understood as restoring the connection between the nozzle and the ink reservoir after cleaning the nozzle, thereby enabling the inkjet system to achieve normal printing results.

[0044] This invention also provides a cleaning system for an inkjet system, which is used to achieve the following: Figures 1 to 4 The cleaning method shown in any of the images below, combined with... Figure 5 The architecture of the cleaning system is illustrated by way of example.

[0045] like Figure 5 As shown, the cleaning system of the inkjet system includes a pressure control module 100 and a motion control module 200. The pressure control module 100 is used to control the formation of a first positive pressure inside the nozzle of the inkjet system. The first positive pressure is used to prevent ink from dripping from the nozzle and to form an ink meniscus barrier at the nozzle. The motion control module 200 is used to control the wiping member to contact the nozzle and move the wiping member relative to the nozzle while maintaining the first positive pressure inside the nozzle, so as to wipe the nozzle.

[0046] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A cleaning method for an inkjet system, characterized in that, The inkjet system is used in a photovoltaic cell production system, and the cleaning method includes: A first positive pressure is formed inside the nozzle of the inkjet system, which is used to prevent ink from dripping from the nozzle and to form an ink meniscus barrier at the nozzle. While maintaining the first positive pressure inside the nozzle, the wiping member is controlled to contact the nozzle and move relative to the nozzle to wipe the nozzle.

2. The cleaning method according to claim 1, characterized in that, The first positive pressure is positively correlated with the surface tension of the ink and the cosine of the contact angle between the nozzle and the wiping element; the first positive pressure is negatively correlated with the nozzle orifice radius.

3. The cleaning method according to claim 1 or 2, characterized in that, The first positive pressure is between 0.5 and 1 kPa.

4. The cleaning method according to claim 1, characterized in that, The control of forming a first positive pressure within the nozzle of the inkjet system includes: The movement speed of the wiping component and the distance between the wiping component and the nozzle are obtained, and the contact time point between the wiping component and the nozzle is calculated based on the movement speed and the distance. The time point before the preset duration of the contact time point is determined as the positive pressure establishment time point, and the first positive pressure is formed in the nozzle of the inkjet system at the positive pressure establishment time point.

5. The cleaning method according to claim 1, characterized in that, After the control wiper contacts the nozzle and moves relative to the nozzle, the cleaning method further includes: When the wiping member is separated from the nozzle, a second positive pressure is formed inside the nozzle and maintained for a preset duration so that ink is ejected from the nozzle, wherein the second positive pressure is greater than the first positive pressure.

6. The cleaning method according to claim 5, characterized in that, The step of creating a second positive pressure within the nozzle and maintaining it for a preset duration while the wiping member is separated from the nozzle includes: After a preset time delay from the point at which the wiping element separates from the nozzle, a second positive pressure is formed inside the nozzle and maintained for a preset duration.

7. The cleaning method according to claim 6, characterized in that, The second positive pressure is greater than 5 kPa, the preset duration is between 0.5 and 1 second, and the time delay is less than 100 milliseconds.

8. The cleaning method according to claim 1, characterized in that, After the control wiper contacts the nozzle and moves relative to the nozzle, the cleaning method further includes: With the wiping element separated from the nozzle, a negative pressure is controlled to form inside the nozzle.

9. The cleaning method according to claim 1, characterized in that, The inkjet system includes an ink reservoir for storing ink, and the nozzle is in communication with the ink reservoir. Before a first positive pressure is formed within the nozzle controlling the inkjet system, the cleaning method further includes: Control the nozzle to isolate it from the ink reservoir; While maintaining the first positive pressure within the nozzle, after controlling the wiping member to contact the nozzle and moving the wiping member relative to the nozzle, the cleaning method further includes: Control the nozzle to connect with the ink reservoir.

10. A cleaning system for an inkjet system, characterized in that, The cleaning system includes: A pressure control module is used to control the formation of a first positive pressure inside the nozzle of the inkjet system. The first positive pressure is used to prevent ink from dripping from the nozzle and to form an ink meniscus barrier at the nozzle. A motion control module is used to control the wiping member to contact the nozzle and move the wiping member relative to the nozzle while maintaining the first positive pressure inside the nozzle, so as to wipe the nozzle.

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