Ink path structure of ink-jet printing equipment

Abstract

The embodiment of the utility model relates to an ink path structure of ink-jet printing equipment, which can respectively form a jet printing loop, a diluent adding loop and a cleaning loop when the ink-jet printing equipment works, and the jet printing loop comprises a positive pressure pipeline, a nozzle pipeline, a recovery pipeline and a negative pressure pipeline, the mixing cylinder is communicated with an inlet of the nozzle through a positive pressure pipeline and a nozzle pipeline in sequence, and the recovery pipe is communicated with the mixing cylinder through a recovery pipeline and a negative pressure pipeline in sequence; the diluent adding loop comprises a solvent pipeline, a slow arrangement pipeline and a negative pressure pipeline, and the solvent cylinder is communicated with the mixing cylinder through the solvent pipeline, the slow arrangement pipeline and the negative pressure pipeline in sequence; the cleaning loop comprises a positive pressure pipeline, a back flushing pipeline, a slow arrangement pipeline, a cleaning pipeline, a recovery pipeline and a negative pressure pipeline, the mixing cylinder is communicated with an inlet of the nozzle through the positive pressure pipeline, the back flushing pipeline, the slow arrangement pipeline and the cleaning pipeline in sequence, and the recovery pipeline is communicated with the mixing cylinder through the recovery pipeline and the negative pressure pipeline in sequence. According to the utility model, the cleaning time is shorter, and the consumed diluent is less.

Description

Technical Field

[0001] The utility model belongs to the technical field of inkjet printing, and in particular relates to an ink path structure of an inkjet printing device. Background Art

[0002] The working principle of a small character inkjet printer is that under pressure, ink enters the nozzle chamber, which is equipped with a crystal oscillator. Through vibration, the ink is ejected from a nozzle with an extremely small aperture (usually 60 microns) to form fixed-interval dots. Through CPU processing and phase tracking, some ink dots passing through the charging electrode are charged with positive and negative charges, which are deflected differently under a high-voltage magnetic field of several thousand volts, fly out of the nozzle and fall on the surface of the moving product, forming a dot matrix, thereby forming text, numbers or graphics.

[0003] Small character inkjet printers are designed for applications where the ink dries immediately after printing. The ink used is highly volatile. However, the continuous flow of volatile ink increases the ink viscosity, necessitating frequent addition of diluent to maintain the ink viscosity within a normal range. Due to the high volatility of the ink used, when the printer is not in operation, it is important to ensure that parts exposed to air, such as the nozzle and recovery tube, do not become clogged due to drying ink.

[0004] In the prior art, there are several methods to prevent ink from drying up and clogging the nozzle and recovery pipe of the inkjet printer:

[0005] An existing technology such as Figure 1 and Figure 2 As shown, when the small character inkjet printer is printing, Figure 1 As shown, the recovery tube is separated from the nozzle by a predetermined distance. When the small-character inkjet printer stops printing, a mechanical device is used to move the recovery tube so that its recovery port mates with the nozzle's orifice, sealing it and preventing ink from leaking and drying. A disadvantage of this method is that the mechanical device for moving the recovery tube is built into the printer's printhead. This device includes a complex series of mechanical components, including a drive motor, a lead screw, and a slider, increasing the probability of mechanical failure.

[0006] Another existing technology is Figure 3 As shown in the figure, when the small character inkjet printer stops printing, the nozzle and recovery pipe are cleaned with diluent to prevent ink clogging. To speed up the cleaning process and reduce the amount of diluent used, four miniature solenoid valves are installed in the printer's printhead. The disadvantage of this method is that the increase in parts is not conducive to the miniaturization of the inkjet printer product and also increases the equipment failure rate.

[0007] Another existing technology is Figure 4 As shown, it is in Figure 3The technical solution shown in the figure is further improved. A larger medium-sized electromagnetic valve can be used in the inkjet printer's nozzle instead of a micro electromagnetic valve. At the same time, the cleaning pump in the ink path is eliminated. Figure 4 As shown, the solvent tank is used to hold a diluent, and the mixing tank is used to hold ink to which the diluent can be added. The diluent is used to dilute the ink to achieve the desired viscosity. The solvent tank is connected to the mixing tank via an addition line 108 equipped with a solvent valve and a negative pressure line 109 equipped with a recovery pump. The mixing tank is connected to the first end of the ink supply valve via a positive pressure line 101, and the solvent tank is connected to the second end of the ink supply valve via a purge line 106. The purge line 106 is equipped with a purge valve to open or close the purge line. The third end of the ink supply valve can be switched to connect to either the first or second end of the ink supply valve. The third end of the ink supply valve is connected to the first end of the nozzle valve via an ink supply line 102, and the second end of the nozzle valve is connected to the nozzle inlet via a nozzle line 103. The volume of the ink supply line 102 is larger than that of the nozzle line 103, and the nozzle valve is a two-way valve. The nozzle inlet is connected to the mixing cylinder via a drain line 107 equipped with a drain valve and a negative pressure line 109 equipped with a recovery pump. The nozzle inlet is connected to the second end of the drain valve, a two-way valve whose first end is connected to the drain line 107. The recovery pipe is connected to the first end of the recovery valve via a recovery line 104, and the third end of the recovery valve is connected to the mixing cylinder via a negative pressure line equipped with a recovery pump. The first end of the nozzle valve is also connected to the second end of the recovery valve via an ink drain line 105, and the third end of the recovery valve can be switched to connect to either the first or second end of the recovery valve. Furthermore, a filter is provided on the ink supply line 102, and an ink supply pump, filter, pressure sensor, buffer, and ink viscosity detection device are also provided on the positive pressure line 101. Because small character inkjet printers continuously draw air from the recovery path during printing, the viscosity of the ink in the ink system increases due to the evaporation of the diluent. Therefore, the inkjet printer will always monitor the viscosity of the ink during operation. When the viscosity is higher than the set value, it will automatically add diluent to the ink system to maintain the viscosity of the ink.

[0008] When the viscosity of the ink in the positive pressure line 101 is higher than the viscosity setting value required for printing, a certain amount of diluent in the solvent tank is added to the mixing tank through the adding line 108 and the negative pressure line 109 to reduce the viscosity of the ink in the mixing tank.

[0009] During printing, the drain valve is closed, the first and third ends of the ink supply valve are connected, the nozzle valve is opened, the first and second ends of the nozzle valve are connected, and the first and third ends of the recovery valve are connected. Ink of a certain viscosity passes through the positive pressure line 101, the ink supply line 102, and the nozzle line 103, and is ejected from the nozzle to print. The recovered ink is received by the recovery pipe and, under the action of the recovery pump, returns to the mixing tank through the recovery line 104 and the negative pressure line 109.

[0010] In order to prevent the ink in the exposed parts of the printer, the nozzle pipe 103 and the recovery pipe from drying up and blocking the ink path, before the inkjet printing device stops running, Figure 4 The embodiment cleans the printhead as follows. First, the drain valve is closed, the nozzle valve is closed, the purge valve is opened, and the ink supply valve and recovery valve are switched so that the second end of the ink supply valve is connected to the third end, and the second end of the recovery valve is connected to the third end. The diluent in the solvent tank enters the ink supply pipe 102 through the purge line 106, filling the ink supply pipe 102 with the diluent. The ink in the ink supply pipe 102 is then returned to the mixing tank through the ink drain line 105 and the negative pressure line 109. Next, the purge valve is closed, and the ink supply valve, nozzle valve, and recovery valve are switched so that the first end of the ink supply valve is connected to the third end, the first end of the nozzle valve is connected to the second end, and the first end of the recovery valve is connected to the third end. Ink from the mixing tank enters the ink supply pipe 102 through the positive pressure line 101. The diluent in the ink supply pipe 102 is pushed into the nozzle pipe 103, expelled from the nozzle, and injected into the recovery pipe. The diluent then returns to the mixing tank through the recovery line 104 and the negative pressure line 109. During this process, since the volume of the ink supply pipeline 102 is larger than that of the nozzle pipeline 103, the diluent in the ink supply pipeline 102 is actually used to clean the nozzle pipeline 103, so that after cleaning, the nozzle pipeline 103 is filled with the diluent.

[0011] Furthermore, since the nozzle conduit 103 is filled with diluent after cleaning, the diluent in the nozzle conduit 103 needs to be drained before printing. To do this, the drain valve needs to be opened, and the first and third ends of the ink supply valve and the first and second ends of the nozzle valve need to be connected. Ink from the mixing tank flows through the positive pressure conduit 101 into the ink supply conduit 102 and the nozzle conduit 103, and the diluent in the nozzle conduit 103 is drained back into the mixing tank through the drain conduit 107 and the negative pressure conduit 109.

[0012] Figure 4 The ink path structure shown greatly reduces the failure rate of the equipment. However, when adding diluent, the diluent directly enters the negative pressure circuit of the ink path system after passing through the ink supply valve. During cleaning, it is necessary to first clean the pipeline between the cleaning valve and the nozzle valve, and then flush the nozzle and the recovery pipe. The cleaning process takes too long and consumes a large amount of diluent, resulting in a significant decrease in ink viscosity after each cleaning. Utility Model Content

[0013] In order to solve the above technical problems, the utility model proposes an ink path structure of an inkjet printing device, which includes a solvent tank for holding a diluent, a mixing tank for holding ink, a nozzle, a recovery pipe, a positive pressure pipeline, a nozzle pipeline, a recovery pipeline, a backflush pipeline, a buffer pipeline, a negative pressure pipeline, a cleaning pipeline and a solvent pipeline. When the inkjet printing device is working, the ink path structure can form a printing circuit, a diluent addition circuit and a cleaning circuit respectively.

[0014] The printing circuit includes a positive pressure pipeline, a nozzle pipeline, a recovery pipeline and a negative pressure pipeline. The mixing cylinder is connected to the inlet of the nozzle through the positive pressure pipeline and the nozzle pipeline in sequence. The recovery pipe is connected to the mixing cylinder through the recovery pipeline and the negative pressure pipeline in sequence.

[0015] The diluent adding circuit includes a solvent pipeline, a buffer pipeline and a negative pressure pipeline, and the solvent cylinder is connected to the mixing cylinder through the solvent pipeline, the buffer pipeline and the negative pressure pipeline in sequence;

[0016] The cleaning circuit includes a positive pressure pipeline, a backflush pipeline, a buffer pipeline, a cleaning pipeline, a recovery pipeline and a negative pressure pipeline. The mixing cylinder is connected to the inlet of the nozzle through the positive pressure pipeline, the backflush pipeline, the buffer pipeline and the cleaning pipeline in sequence, and the recovery pipe is connected to the mixing cylinder through the recovery pipeline and the negative pressure pipeline in sequence.

[0017] In a preferred embodiment, the ink path structure further includes an ink supply valve, a purge valve, and a backflush valve. The ink supply valve and the backflush valve are three-way valves. The first end of the ink supply valve can be switched to communicate with the second end or the third end thereof, and the second end of the backflush valve can be switched to communicate with the first end or the third end thereof. The purge valve is a two-way valve.

[0018] The mixing cylinder is connected to the first end of the ink supply valve through the positive pressure pipeline, and the third end of the ink supply valve is connected to the inlet of the nozzle through the nozzle pipeline;

[0019] The second end of the ink supply valve is connected to the third end of the backflush valve through the backflush pipeline, the second end of the backflush valve is connected to the first end of the purge valve through the buffer pipeline, and the second end of the purge valve is connected to the inlet of the nozzle through the purge pipeline, so that the purge pipeline is connected to the nozzle pipeline;

[0020] One of the first ends of the purge valve and the backflush valve is communicated with the solvent cylinder through the solvent pipeline, and the other of the first ends of the purge valve and the backflush valve is communicated with the mixing cylinder through the negative pressure pipeline.

[0021] In a preferred embodiment, the volume of the buffer pipeline is greater than the volume of the cleaning pipeline.

[0022] In a preferred embodiment, the ink path structure further includes a nozzle valve, a recovery valve and an exhaust pipeline. The nozzle valve is a two-way valve, the recovery valve is a three-way valve, and the third end of the recovery valve can be switched to communicate with the first end or the second end.

[0023] The printhead pipeline includes an ink supply pipeline and a nozzle pipeline, the third end of the ink supply valve is connected to the first end of the nozzle valve through the ink supply pipeline, and the second end of the nozzle valve is connected to the inlet of the nozzle through the nozzle pipeline, so that the nozzle pipeline is connected to the cleaning pipeline;

[0024] The recovery pipe is connected to the first end of the recovery valve through the recovery pipeline, the third end of the recovery valve is connected to the mixing cylinder through the negative pressure pipeline, and the first end of the nozzle valve is also connected to the second end of the recovery valve through the emptying pipeline.

[0025] In a preferred embodiment, the volume of the buffer pipeline is greater than the sum of the volumes of the nozzle pipeline and the cleaning pipeline.

[0026] In a preferred embodiment, the liquid flow direction of the diluent adding circuit in the buffer pipe is the same as the liquid flow direction of the cleaning circuit in the buffer pipe.

[0027] The ink circuit structure further includes an addition pipeline, and an addition valve is provided on the addition pipeline, and the addition valve is used to open or close the addition pipeline.

[0028] The solvent cylinder is communicated with the first end of the backflush valve through the solvent pipeline, and the first end of the cleaning valve is communicated with the mixing cylinder through the addition pipeline and the negative pressure pipeline in sequence.

[0029] In a preferred embodiment, the liquid flow direction of the diluent adding circuit in the buffer line is opposite to the liquid flow direction of the cleaning circuit in the buffer line.

[0030] The solvent cylinder is connected to the first end of the cleaning valve through the solvent pipeline, and the first end of the backflush valve is connected to the mixing cylinder through the negative pressure pipeline.

[0031] The solvent pipeline is provided with a solvent valve, and the solvent valve is used to open or close the solvent pipeline.

[0032] In a preferred embodiment, the ink circuit structure further includes an addition pipeline, which is connected between the first end of the backflush valve and the negative pressure pipeline.

[0033] The adding pipeline is provided with an adding valve, and the adding valve is used to open or close the adding pipeline.

[0034] In a preferred embodiment, the positive pressure pipeline is further provided with an ink viscosity detection device, and the negative pressure pipeline is provided with a recovery pump.

[0035] In a preferred embodiment, the ink viscosity detection device includes a throttle valve, a viscosity valve and a viscosity detection pipeline connected between the positive pressure pipeline and the mixing cylinder. The throttle valve and the viscosity valve are arranged in series on the viscosity detection pipeline. The throttle valve is arranged on the upstream side of the viscosity valve. The ink from the positive pressure pipeline can pass through the throttle valve and the viscosity valve in sequence and return to the mixing cylinder.

[0036] Beneficial effects of the utility model:

[0037] The ink path system of the embodiment of the present invention utilizes the characteristic that diluent must be frequently added during normal operation of the printing equipment. When the diluent is added to adjust the ink viscosity, the buffer pipeline between the backflush valve and the cleaning valve has been cleaned (to accommodate the diluent). When the cleaning procedure is executed, there is no need to clean this section of the pipeline again, and the nozzle and the recovery pipe can be cleaned directly, thereby shortening the time and consuming less diluent. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 、 Figure 2 It is a schematic diagram of a technical solution in the prior art;

[0039] Figure 3 It is a schematic diagram of another technical solution in the prior art;

[0040] Figure 4 It is a schematic diagram of another technical solution in the prior art;

[0041] Figure 5 The ink path structure of the inkjet printing device proposed in the first embodiment of the present utility model;

[0042] Figure 6 This is an ink path structure of an inkjet printing device proposed according to the second embodiment of the present utility model. DETAILED DESCRIPTION

[0043] To make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings. However, those skilled in the art will appreciate that the present invention is not limited to the accompanying drawings and the following embodiments.

[0044] As described herein, the term "including" and its various variations are to be understood as open-ended terms, meaning "including but not limited to." The term "based on" and similar expressions are to be understood as meaning "based on at least." Terms such as "first," "second," and "third" are merely used to distinguish different features and have no substantive meaning. Terms such as "left," "right," and "middle" are merely used to indicate the positional relationship between relative objects.

[0045] An embodiment of the present utility model provides an ink path structure of an inkjet printing device, which includes a solvent tank for holding a diluent, a mixing tank for holding ink, a nozzle, a recovery pipe, a positive pressure pipeline 1, a nozzle pipeline, a recovery pipeline 4, a backflush pipeline 6, a buffer pipeline 7, a negative pressure pipeline 9, a cleaning pipeline 10 and a solvent pipeline 11, which can respectively form a printing circuit, a diluent addition circuit and a cleaning circuit when the inkjet printing device is working. The printing circuit includes a positive pressure pipeline 1, a nozzle pipeline, a recovery pipeline 4 and a negative pressure pipeline 9. The mixing cylinder is connected to the inlet of the nozzle through the positive pressure pipeline 1 and the nozzle pipeline in sequence, and the recovery pipe is connected to the mixing cylinder through the recovery pipeline 4 and the negative pressure pipeline 9 in sequence; the diluent addition circuit includes a solvent pipeline 11, a buffer pipeline 7 and a negative pressure pipeline 9. The solvent cylinder is connected to the mixing cylinder through the solvent pipeline 11, the buffer pipeline 7 and the negative pressure pipeline 9 in sequence; the cleaning circuit includes a positive pressure pipeline 1, a backflush pipeline 6, a buffer pipeline 7, a cleaning pipeline 10, a recovery pipeline 4 and a negative pressure pipeline 9. The mixing cylinder is connected to the inlet of the nozzle through the positive pressure pipeline 1, the backflush pipeline 6, the buffer pipeline 7 and the cleaning pipeline 10 in sequence, and the recovery pipe is connected to the mixing cylinder through the recovery pipeline 4 and the negative pressure pipeline 9 in sequence.

[0046] It should be noted that in the technical solution of the embodiment of the present invention, the printing circuit, the diluent addition circuit, and the cleaning circuit are the liquid circulation paths of the inkjet printing device during operation, and each circulation path has a reused pipeline. The following is a detailed description of the present invention based on the accompanying drawings.

[0047] According to the first embodiment of the present invention, an ink path structure of an inkjet printing device is proposed, such as Figure 5 As shown, the ink circuit structure includes a solvent cylinder, a mixing cylinder, an ink supply valve, a nozzle valve, a nozzle, a cleaning valve, a backflush valve, a recovery pipe, a recovery valve, a positive pressure pipeline 1, a nozzle pipeline (ink supply pipeline 2 and nozzle pipeline 3), a recovery pipeline 4, an emptying pipeline 5, a backflush pipeline 6, a buffer pipeline 7, an adding pipeline 8, a negative pressure pipeline 9, a cleaning pipeline 10 and a solvent pipeline 11. The cleaning valve and the nozzle valve are two-way valves, and the ink supply valve, the backflush valve and the recovery valve are three-way valves.

[0048] The solvent tank is used to hold a diluent, and the mixing tank is used to hold ink to which a diluent can be added. The diluent is used to dilute the ink to achieve a desired viscosity.

[0049] The mixing cylinder is connected to the first end of the ink supply valve through the positive pressure pipeline 1, the third end of the ink supply valve is connected to the first end of the nozzle valve through the ink supply pipeline 2, and the second end of the nozzle valve is connected to the nozzle inlet through the nozzle pipeline 3.

[0050] The recovery pipe is connected to the first end of the recovery valve via a recovery line 4. The third end of the recovery valve is connected to the mixing cylinder via a negative pressure line 9 equipped with a recovery pump. The first end of the nozzle valve is also connected to the second end of the recovery valve via an exhaust line 5. The third end of the recovery valve can be switched to connect to the first or second end of the recovery valve. The nozzle valve is a two-way valve, and the first end of the nozzle valve is connected or disconnected from the second end. When the first end of the nozzle valve is connected to the second end and the second end of the recovery valve is connected to the third end, liquid, such as diluent, can be sucked in through the nozzle outlet under the suction action of the recovery pump of the negative pressure line, and the nozzle line 3 can be manually cleaned.

[0051] The solvent cylinder is connected to the first end of the backflush valve via a solvent line 11. The third end of the backflush valve is connected to the second end of the ink supply valve via a backflush line 6. The first end of the ink supply valve can be switched to connect to the second or third end of the ink supply valve. The second end of the backflush valve is connected to the first end of the purge valve via a buffer line 7. The first end of the purge valve is also connected to the mixing cylinder via an addition line 8 equipped with an addition valve and a negative pressure line 9 equipped with a recovery pump. The addition valve in the addition line 8 is used to open or close the addition line 8. The second end of the backflush valve can be switched to connect to the first or third end of the backflush valve. The second end of the purge valve is connected to the nozzle inlet via a purge line 10, thereby connecting the purge line 10 to the nozzle line 3. In which, the cleaning valve is a two-way valve, the first end of the cleaning valve is connected or disconnected with the second end, the volume of the buffer line 7 is at least larger than the volume of the cleaning line 10, and preferably the volume of the buffer line 7 is larger than the sum of the volumes of the nozzle line 3 and the cleaning line 10.

[0052] In addition, if Figure 5As shown, the ink supply line 2 is also equipped with a buffer and a filter, and the positive pressure line 1 is also equipped with an ink supply pump, a filter, a pressure sensor, and an ink viscosity detection device. Because the ink continuously draws air from the recovery path during the printing process, the viscosity of the ink in the ink system increases due to the volatilization of the diluent. Therefore, the inkjet printing device continuously monitors the viscosity of the ink in the positive pressure line 1 during operation. When the viscosity exceeds a set value, diluent is added to the ink path to maintain the ink viscosity. In this embodiment, the ink viscosity detection device includes a throttle valve, a viscosity valve, and a viscosity detection line connecting the positive pressure line and the mixing tank. The throttle valve and the viscosity valve are arranged in series on the viscosity detection line, with the throttle valve positioned upstream of the viscosity valve. Ink from the positive pressure line can sequentially pass through the throttle valve and the viscosity valve and return to the mixing tank. The throttle valve controls the flow of ink entering the viscosity valve by changing the throttle cross-section or throttle length. The viscosity valve detects the viscosity of the ink in the positive pressure line.

[0053] Those skilled in the art will understand that the operation of adding diluent is frequently performed during the operation of the inkjet printing device. When the viscosity of the ink in the positive pressure pipeline 1 is higher than the viscosity setting value required for printing, a certain amount of diluent in the solvent tank is added to the mixing tank through the solvent pipeline 11, the buffer pipeline 7, and the adding pipeline 8 to reduce the viscosity of the ink in the mixing tank.

[0054] In this embodiment, during the printing process, the first end of the ink supply valve is connected to the third end, the first end of the nozzle valve is connected to the second end, the first end of the recovery valve is connected to the third end, the first end of the backflush valve is connected to the second end, and the purge valve is disconnected. Ink with a certain viscosity passes through the positive pressure line 1, the ink supply line 2, and the nozzle line 3, and is ejected through the nozzle outlet for printing. The recovered ink is received by the recovery pipe and sucked back to the mixing cylinder through the recovery line 4 and the negative pressure line 9. When diluent needs to be added, the addition valve is opened, and the diluent is sucked from the solvent cylinder into the mixing cylinder through the solvent line 11, the buffer line 7, the addition line 8, and the negative pressure line 9 to dilute the ink in the mixing cylinder. Since the operation of adding diluent is performed frequently during printing, the buffer line 7 will be filled with diluent after the printing is completed.

[0055] In order to prevent the ink in the exposed parts of the printer - the nozzle and the recovery tube from drying up and blocking the ink path, before the inkjet printing equipment stops running, Figure 5The embodiment cleans the printhead as follows. During cleaning, the first and second ends of the ink supply valve are connected, the third and second ends of the backflush valve are connected, the first and second ends of the purge valve are connected (the purge valve is open), and the first and third ends of the recovery valve are connected. Ink from the positive pressure line 1 flows through the backflush line 6 into the buffer line 7. The diluent in the buffer line 7 is pushed into the nozzle through the purge line 10, and then extruded from the nozzle outlet into the recovery line. The diluent then returns to the mixing tank via the recovery line 4 and the negative pressure line 9. Since the purge line 10 is typically exposed, it is undesirable to store ink in the purge line 10 after cleaning. Therefore, the volume of the buffer line 7 is at least larger than that of the purge line 10.

[0056] Furthermore, in order to achieve a better cleaning effect, it is preferred to clean the exposed nozzle pipeline 3 during cleaning. In an embodiment of the present invention, the nozzle valve is opened so that the first end of the nozzle valve is connected to the second end, the second end of the recovery valve is switched to be connected to the third end, the first end of the nozzle valve is connected to the second end of the recovery valve through the emptying pipeline 5, the diluent in the buffer pipeline 7 is pushed into the cleaning pipeline 10 and the nozzle pipeline 3, and returned to the mixing tank through the emptying pipeline 5 and the negative pressure pipeline 9, thereby completing the cleaning of the nozzle pipeline 3. It will be understood by those skilled in the art that in an inkjet printing device, the diameter of the nozzle pipeline 3 is much larger than the nozzle outlet diameter. Therefore, during cleaning, the cleaning time of the nozzle pipeline 3 is short, that is, the period when the first end of the nozzle valve is connected to the second end and the second end of the recovery valve is connected to the third end is short, and then it is necessary to switch back to the state where the first end of the recovery valve is connected to the third end until the entire cleaning process is completed. It is easy for those skilled in the art to understand that, in this case, the volume of the buffer pipeline 7 is greater than the sum of the volumes of the nozzle pipeline 3 and the cleaning pipeline 10 .

[0057] In the ink system of this embodiment, when adding diluent to adjust the ink viscosity, the buffer pipe 7 between the recoil valve and the cleaning valve has been cleaned. When executing the cleaning procedure, there is no need to clean this section of the pipe again, and the nozzle and recovery pipe are cleaned directly, which saves time and consumes less diluent.

[0058] According to the second embodiment of the present invention, another ink path structure of an inkjet printing device is proposed, such as Figure 6 As shown, the ink circuit structure includes a solvent cylinder, a mixing cylinder, an ink supply valve, a nozzle valve, a nozzle, a cleaning valve, a backflush valve, a recovery pipe, a recovery valve, a positive pressure pipeline 1, an ink supply pipeline 2, a nozzle pipeline 3, a recovery pipeline 4, an emptying pipeline 5, a backflush pipeline 6, a buffer pipeline 7, an adding pipeline 8, a negative pressure pipeline 9, a cleaning pipeline 10 and a solvent pipeline 11. The cleaning valve and the nozzle valve are two-way valves, and the ink supply valve, the backflush valve and the recovery valve are three-way valves.

[0059] The solvent tank is used to hold a diluent, and the mixing tank is used to hold ink to which a diluent can be added. The diluent is used to dilute the ink to achieve a desired viscosity.

[0060] The mixing cylinder is connected to the first end of the ink supply valve through the positive pressure pipeline 1, the third end of the ink supply valve is connected to the first end of the nozzle valve through the ink supply pipeline 2, and the second end of the nozzle valve is connected to the nozzle inlet through the nozzle pipeline 3.

[0061] The recovery pipe is connected to the first end of the recovery valve via a recovery line 4, and the third end of the recovery valve is connected to the mixing cylinder via a negative pressure line 9 equipped with a recovery pump. The first end of the nozzle valve is also connected to the second end of the recovery valve via an exhaust line 5, and the third end of the recovery valve can be switched to connect to the first end or the second end of the recovery valve. The nozzle valve is a two-way valve, and the first end of the nozzle valve is connected or disconnected from the second end.

[0062] The solvent cylinder is connected to the first end of the cleaning valve via a solvent line 11 equipped with a solvent valve, and the solvent valve is used to open or close the solvent line 11. The second end of the cleaning valve is connected to the inlet of the nozzle via a cleaning line 10, so that the cleaning line 10 is connected to the nozzle line 3. The first end of the cleaning valve is also connected to the second end of the backflush valve via a buffer line 7. The cleaning valve is a two-way valve, and the first end of the cleaning valve is connected or disconnected to the second end. The third end of the backflush valve is connected to the second end of the ink supply valve via a backflush line 6, and the first end of the ink supply valve can be switched to be connected to the second end or the third end of the ink supply valve. The first end of the backflush valve is connected to the mixing cylinder via an addition line 8 equipped with an addition valve and a negative pressure line 9 equipped with a recovery pump, and the second end of the backflush valve can be switched to be connected to the first end or the third end of the backflush valve. The addition valve in addition line 8 is used to open or close addition line 8, reducing bubbles generated by switching the backflush valve in the line. It also facilitates more flexible cleaning program design, thereby reducing cleaning downtime. In this embodiment, the volume of the buffer line 7 is at least greater than the volume of the cleaning line 10. Preferably, the volume of the buffer line 7 is greater than the combined volume of the nozzle line 3 and the cleaning line 10.

[0063] In addition, if Figure 6 As shown, the ink supply line 2 is also equipped with a buffer and a filter, and the positive pressure line 1 is also equipped with an ink supply pump, a filter, a pressure sensor, and an ink viscosity detection device. Because the ink continuously draws air from the recovery path during the printing process, the viscosity of the ink in the ink system increases due to the evaporation of the diluent. Therefore, the inkjet printing device continuously monitors the viscosity of the ink in the positive pressure line 1 during operation. When the viscosity exceeds the set value, diluent is added to the ink path to maintain the ink viscosity. This addition of diluent is performed frequently during the operation of the inkjet printing device.

[0064] In this embodiment, during the printing process, the first end of the ink supply valve is connected to the third end, the first end of the nozzle valve is connected to the second end, the first end of the recovery valve is connected to the third end, the first end of the backflush valve is connected to the second end, and the purge valve is disconnected. Ink with a certain viscosity passes through the positive pressure line 1, the ink supply line 2, and the nozzle line 3, and is ejected through the nozzle outlet for printing. The recovered ink is received by the recovery pipe and sucked back into the mixing tank through the recovery line 4 and the negative pressure line 9. When diluent needs to be added, the solvent valve and the addition valve are opened, and the diluent is sucked from the solvent tank into the mixing tank through the solvent line 11, the buffer line 7, the addition line 8, and the negative pressure line 9 to dilute the ink in the mixing tank. Since the operation of adding diluent is performed frequently during printing, the buffer line 7 will be filled with diluent after printing is completed.

[0065] In order to prevent the ink in the exposed parts of the printer - the nozzle and the recovery tube from drying up and blocking the ink path, before the inkjet printing equipment stops running, Figure 6 The embodiment cleans the printhead as follows. During cleaning, the first and second ends of the ink supply valve are connected, the third and second ends of the backflush valve are connected, the first and second ends of the purge valve are connected (the purge valve is open), and the first and third ends of the recovery valve are connected. Ink from the positive pressure line 1 flows through the backflush line 6 into the buffer line 7. The diluent in the buffer line 7 is pushed into the nozzle through the purge line 10, and then extruded from the nozzle outlet into the recovery line. The diluent then returns to the mixing tank via the recovery line 4 and the negative pressure line 9. Since the purge line 10 is typically exposed, it is undesirable to store ink in the purge line 10 after cleaning. Therefore, the volume of the buffer line 7 is at least larger than that of the purge line 10.

[0066] Furthermore, in order to achieve a better cleaning effect, it is preferred to clean the exposed nozzle pipeline 3 during cleaning. In an embodiment of the present invention, the nozzle valve is opened so that the first end of the nozzle valve is connected to the second end, the second end of the recovery valve is switched to be connected to the third end, the first end of the nozzle valve is connected to the second end of the recovery valve through the emptying pipeline 5, the diluent in the buffer pipeline 7 is pushed into the cleaning pipeline 10 and the nozzle pipeline 3, and returned to the mixing tank through the emptying pipeline 5 and the negative pressure pipeline 9, thereby completing the cleaning of the nozzle pipeline 3. It will be understood by those skilled in the art that in an inkjet printing device, the diameter of the nozzle pipeline 3 is much larger than the nozzle outlet diameter. Therefore, during cleaning, the cleaning time of the nozzle pipeline 3 is short, that is, the period when the first end of the nozzle valve is connected to the second end and the second end of the recovery valve is connected to the third end is short, and then it is necessary to switch back to the state where the first end of the recovery valve is connected to the third end until the entire cleaning process is completed. It is easy for those skilled in the art to understand that, in this case, the volume of the buffer pipeline 7 is greater than the sum of the volumes of the nozzle pipeline 3 and the cleaning pipeline 10 .

[0067] In the first embodiment, the direction of liquid flow in the buffer line 7 is the same during addition of diluent and cleaning. In the second embodiment, the direction of liquid flow in the buffer line 7 is reversed during addition of diluent and cleaning of the nozzle. This facilitates faster flushing of the buffer line 7 with residual diluent from cleaning when restarting normal operation and adding diluent after cleaning the nozzle, thereby consuming less diluent.

[0068] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0069] The above describes the implementation methods of the present invention. However, the present invention is not limited to the above implementation methods. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the scope of protection of the present invention.

Claims

1. An ink path structure of an inkjet printing device, characterized in that: The ink path structure comprises a solvent tank for holding a diluent, a mixing tank for holding ink, a nozzle, a recovery pipe, a positive pressure pipe (1), a nozzle pipe, a recovery pipe (4), a backflush pipe (6), a buffer pipe (7), a negative pressure pipe, a cleaning pipe (10) and a solvent pipe (11), which can respectively form a printing circuit, a diluent adding circuit and a cleaning circuit when the inkjet printing device is working. The printing circuit includes a positive pressure pipeline (1), a nozzle pipeline, a recovery pipeline (4) and a negative pressure pipeline. The mixing cylinder is connected to the inlet of the nozzle through the positive pressure pipeline (1) and the nozzle pipeline in sequence, and the recovery pipe is connected to the mixing cylinder through the recovery pipeline (4) and the negative pressure pipeline in sequence. The diluent adding circuit comprises a solvent pipeline (11), a buffer pipeline (7) and a negative pressure pipeline, and the solvent cylinder is connected to the mixing cylinder via the solvent pipeline (11), the buffer pipeline (7) and the negative pressure pipeline in sequence; The cleaning circuit comprises a positive pressure pipeline (1), a backflush pipeline (6), a buffer pipeline (7), a cleaning pipeline (10), a recovery pipeline (4) and a negative pressure pipeline; the mixing cylinder is connected to the inlet of the nozzle via the positive pressure pipeline (1), the backflush pipeline (6), the buffer pipeline (7) and the cleaning pipeline (10) in sequence; and the recovery pipe is connected to the mixing cylinder via the recovery pipeline (4) and the negative pressure pipeline in sequence.

2. The ink path structure according to claim 1, characterized in that: The ink path structure further includes an ink supply valve, a purge valve, and a backflush valve. The ink supply valve and the backflush valve are three-way valves. The first end of the ink supply valve can be switched to communicate with the second end or the third end thereof. The second end of the backflush valve can be switched to communicate with the first end or the third end thereof. The purge valve is a two-way valve. The mixing cylinder is connected to the first end of the ink supply valve through the positive pressure pipeline (1), and the third end of the ink supply valve is connected to the inlet of the nozzle through the nozzle pipeline; The second end of the ink supply valve is connected to the third end of the backflush valve through the backflush pipeline (6), the second end of the backflush valve is connected to the first end of the cleaning valve through the buffer pipeline (7), and the second end of the cleaning valve is connected to the inlet of the nozzle through the cleaning pipeline (10), so that the cleaning pipeline (10) is connected to the nozzle pipeline; One of the first end of the cleaning valve and the first end of the backflush valve is connected to the solvent cylinder through the solvent pipeline (11), and the other of the first end of the cleaning valve and the first end of the backflush valve is connected to the mixing cylinder through the negative pressure pipeline (9).

3. The ink path structure according to claim 2, characterized in that: The volume of the buffer pipeline (7) is greater than the volume of the cleaning pipeline (10).

4. The ink path structure according to claim 2, wherein: The ink path structure further comprises a nozzle valve, a recovery valve and an exhaust pipeline (5), wherein the nozzle valve is a two-way valve, the recovery valve is a three-way valve, and the third end of the recovery valve can be switched to communicate with the first end or the second end thereof. The nozzle pipeline includes an ink supply pipeline (2) and a nozzle pipeline (3), the third end of the ink supply valve is connected to the first end of the nozzle valve through the ink supply pipeline (2), and the second end of the nozzle valve is connected to the inlet of the nozzle through the nozzle pipeline (3), so that the nozzle pipeline (3) is connected to the cleaning pipeline (10); The recovery pipe is connected to the first end of the recovery valve through the recovery pipeline (4), the third end of the recovery valve is connected to the mixing cylinder through the negative pressure pipeline (9), and the first end of the nozzle valve is also connected to the second end of the recovery valve through the emptying pipeline (5).

5. The ink path structure according to claim 4, characterized in that: The volume of the buffer pipeline (7) is greater than the sum of the volumes of the nozzle pipeline (3) and the cleaning pipeline (10).

6. The ink path structure according to any one of claims 2 to 5, characterized in that: The liquid flow direction of the diluent adding circuit in the slow-down pipe (7) is the same as the liquid flow direction of the cleaning circuit in the slow-down pipe (7). The ink circuit structure further comprises an addition pipeline (8), and an addition valve is provided on the addition pipeline (8), and the addition valve is used to open or close the addition pipeline (8). The solvent cylinder is connected to the first end of the backflush valve through the solvent pipeline (11), and the first end of the cleaning valve is connected to the mixing cylinder through the addition pipeline (8) and the negative pressure pipeline (9) in sequence.

7. The ink path structure according to any one of claims 2 to 5, characterized in that: The liquid flow direction of the diluent adding circuit in the slow-setting pipeline (7) is opposite to the liquid flow direction of the cleaning circuit in the slow-setting pipeline (7). The solvent cylinder is connected to the first end of the cleaning valve through the solvent pipeline (11), and the first end of the backflush valve is connected to the mixing cylinder through the negative pressure pipeline (9). The solvent pipeline (11) is provided with a solvent valve, and the solvent valve is used to open or close the solvent pipeline (11).

8. The ink path structure according to claim 7, wherein: The ink circuit structure further includes an adding pipeline (8), wherein the adding pipeline (8) is connected between the first end of the backflush valve and the negative pressure pipeline (9). An addition valve is provided in the addition pipeline (8), and the addition valve is used to open or close the addition pipeline (8).

9. The ink path structure according to claim 1, wherein: The positive pressure pipeline (1) is also provided with an ink viscosity detection device, and the negative pressure pipeline (9) is provided with a recovery pump.

10. The ink path structure according to claim 9, wherein: The ink viscosity detection device comprises a throttle valve, a viscosity valve and a viscosity detection pipeline connected between the positive pressure pipeline (1) and the mixing cylinder. The throttle valve and the viscosity valve are arranged in series on the viscosity detection pipeline. The throttle valve is arranged on the upstream side of the viscosity valve. The ink from the positive pressure pipeline (1) can return to the mixing cylinder through the throttle valve and the viscosity valve in sequence.

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