inkjet printing equipment

Abstract

This disclosure relates to a printing apparatus comprising a positive pressure supply device connected to a liquid supply device and configured to provide positive pressure to the liquid supply device so that the liquid to be printed in the liquid supply device enters the printhead under positive pressure; a liquid supply device connected to the printhead and configured to contain the liquid to be printed; a printhead configured to eject the liquid to be printed; and a liquid return device connected to the printhead and the liquid supply device and configured to return the liquid to be printed in the printhead to the liquid supply device. This printing apparatus enables the printhead to stably output the liquid to be printed.

Description

Technical Field

[0001] This disclosure relates generally to inkjet printing, and more specifically, to inkjet printing equipment. Background Technology

[0002] Printing equipment (including digital printing) uses printheads to perform printing operations. During the operation of printing equipment, unstable ink output sometimes occurs. For example, ink jetting may be discontinuous (or "ink gap") or uneven (e.g., sometimes exceeding the predetermined ink jet volume and sometimes falling below the predetermined ink jet volume), which seriously affects the printing effect. Summary of the Invention

[0003] This disclosure provides a printing device that enables the printhead to stably output the liquid to be printed.

[0004] According to one aspect of this disclosure, a printing apparatus is provided, comprising: a positive pressure supply device connected to a liquid supply device and configured to supply positive pressure to the liquid supply device such that liquid to be printed in the liquid supply device enters the printhead under positive pressure; a liquid supply device connected to the printhead and configured to contain the liquid to be printed; a printhead configured to eject the liquid to be printed; and a liquid return device connected to the printhead and the liquid supply device and configured to return the liquid to be printed in the printhead to the liquid supply device.

[0005] In some embodiments, the printhead includes: an ink cartridge, the ink cartridge including a receiving cavity for containing liquid to be printed; the printing apparatus further includes: a control device configured to adjust the pressure value of the positive pressure provided by the positive pressure providing device according to at least one of the following: the movement speed of the printhead; the liquid spraying rate of the printhead; and the ambient temperature.

[0006] In some embodiments, the positive pressure supply device includes: a positive pressure pump, connected to a gas storage tank and configured to deliver positive pressure gas to the gas storage tank; and a gas storage tank, connected to a liquid supply device to allow positive pressure gas to enter the liquid supply device to apply positive pressure to the liquid to be printed.

[0007] In some embodiments, the control device is further configured to determine an S-shaped speed curve based on the length of the object to be printed and the target production capacity, and to control the printhead movement based on the S-shaped speed curve.

[0008] In some embodiments, the control device is further configured to adjust the S-shaped speed curve according to the level fluctuation of the liquid to be printed in the ink cartridge, wherein the level fluctuation is the difference between the highest and lowest liquid level values ​​of the liquid to be printed in the ink cartridge within a predetermined time period.

[0009] In some embodiments, the ink cartridge housing is provided with a longitudinal surge protector and a floating device that floats on the surface of the liquid to be printed.

[0010] In some embodiments, the nozzle is provided with a water-cooling pipe and a heat sink.

[0011] In some embodiments, the number of nozzles is multiple, and the multiple nozzles are arranged in a matrix.

[0012] In some embodiments, the liquid supply device further includes: a main liquid storage device, connected to a return liquid device, configured to supply the liquid to be printed that has been returned via the return liquid device to the main liquid storage device; a liquid supply pump, connected to the main liquid storage device, configured to allow the liquid to be printed in the main liquid storage device to enter a degassing device; and a degassing device, connected to the printhead, configured to degas the liquid to be printed flowing through it so that it can enter the printhead.

[0013] In some embodiments, the printing apparatus further includes a cleaning device, and the control device is also configured to shut off the positive pressure supply device and start the cleaning device to clean the printhead.

[0014] In some embodiments, the liquid return device includes: a liquid return bottle in communication with the printhead and configured to store liquid to be printed flowing from the printhead; and a liquid return pump in communication with the liquid return bottle and the liquid supply device and configured to generate a negative pressure to cause the liquid to be printed in the liquid return bottle to flow back to the liquid supply device.

[0015] In some embodiments, the control device is further configured to determine whether the liquid level of the liquid to be printed in the return bottle has reached a predetermined liquid level threshold, and to start the return pump in response to determining that the liquid level of the liquid to be printed in the return bottle has reached the predetermined liquid level threshold.

[0016] The summary section is provided to present the chosen concepts in a simplified form, which will be further described in the detailed description below. The summary section is not intended to identify key or principal features of this disclosure, nor is it intended to limit the scope of this disclosure. Attached Figure Description

[0017] Figure 1 A schematic diagram of a printing apparatus according to an embodiment of the present disclosure is shown.

[0018] Figure 2 A schematic diagram of the positive pressure providing device according to an embodiment of the present disclosure is shown.

[0019] Figure 3 A schematic diagram of the structure of an ink cartridge according to an embodiment of the present disclosure is shown.

[0020] Figure 4 A schematic diagram of a longitudinal surge shield according to an embodiment of the present disclosure is shown.

[0021] Figure 5 A schematic diagram of the structure of a printing unit according to an embodiment of the present disclosure is shown.

[0022] Figure 6 A schematic diagram of the structure of a printing unit according to an embodiment of the present disclosure is shown.

[0023] Figure 7 A schematic diagram of a printing unit performing printing according to an embodiment of the present disclosure is shown.

[0024] Figure 8 A schematic diagram of the structure of a lung negative pressure generating device according to an embodiment of the present disclosure is shown.

[0025] Figure 9 A schematic diagram of an S-shaped velocity curve according to an embodiment of the present disclosure is shown.

[0026] Figure 10 A schematic diagram of the printing process according to an embodiment of the present disclosure is shown.

[0027] In the various figures, the same or corresponding reference numerals indicate the same or corresponding parts. Detailed Implementation

[0028] Preferred embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While preferred embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the present disclosure will be thorough and complete, and will fully convey the scope of the present disclosure to those skilled in the art.

[0029] The term "comprising" and its variations as used herein signify open inclusion, i.e., "including but not limited to". Unless otherwise stated, the term "or" means "and / or". The term "based on" means "at least partially based on". The terms "an example embodiment" and "an embodiment" mean "at least one example embodiment". The term "another embodiment" means "at least one additional embodiment". The terms "first", "second", etc., may refer to different or the same objects. The term "connected (or linked)" as used herein (including the claims) may refer to any direct or indirect means of connection. For example, if the document describes a first device connected to a second device, it should be interpreted as the first device being directly connected to the second device, or the first device being indirectly connected to the second device through other devices or some means of connection.

[0030] As mentioned earlier, in traditional inkjet printing solutions, inkjet printing equipment, such as those based on the siphon principle for ink supply, is prone to unstable inkjet output during the printing process.

[0031] To at least partially address one or more of the aforementioned problems and other potential issues, exemplary embodiments of this disclosure provide a printing apparatus. In this printing apparatus, a positive pressure providing device provides positive pressure to a liquid supply device, causing the liquid to be printed in the liquid supply device to enter the printhead under positive pressure. The liquid supply device contains the liquid to be printed, the printhead ejects the liquid to be printed, and a liquid return device causes the liquid to be printed in the printhead to flow back to the liquid supply device. This printing apparatus, utilizing the positive pressure provided by the positive pressure providing device and the cooperation of the liquid return device, enables the printhead to stably output the liquid to be printed.

[0032] Figure 1 A schematic diagram of a printing apparatus 100 according to an embodiment of the present disclosure is shown. For ease of explanation, Figure 1 The arrows in the diagram illustrate the approximate flow direction of the liquid to be printed during the printing process. For example... Figure 1 As shown, the printing equipment 100 includes, for example, a positive pressure supply device 102, a liquid supply device 104, a printhead 106, and a liquid return device 108. The printing equipment 100 also includes, for example, a control device (not shown). In some embodiments, the printing equipment 100 further includes a cleaning device 103.

[0033] Regarding the positive pressure supply device 102, which is connected to the liquid supply device 102, it is configured to provide positive pressure to the liquid supply device 102 so that the liquid to be printed in the liquid supply device 102 enters the printhead 106 under the action of positive pressure.

[0034] Figure 2 A schematic diagram of a positive pressure supply device 102 according to an embodiment of the present disclosure is shown. The positive pressure supply device 102 includes, for example, a positive pressure pump M1 and an air storage tank 122. The positive pressure supply device 102 may also include a first air filter 124, a third solenoid valve SV3, a second pressure gauge AP2, and a fifth solenoid valve SV5. The positive pressure supply device 102 may also include a fourth solenoid valve SV4 and a first throttle valve TV1.

[0035] Positive pressure pump M1 is connected to gas tank 122 and is configured to supply positive pressure gas to gas tank 122. Gas tank 122 is connected to liquid supply device 104 so that positive pressure gas enters liquid supply device 104 to apply positive pressure to the liquid to be printed.

[0036] In some embodiments, the first air filter 124 is connected to the input port of the positive pressure pump M1, the output port of the positive pressure pump M1 is connected to the air inlet of the air storage tank 122 through the third solenoid valve SV3, and the air outlet of the air storage tank 122 is connected to the liquid supply device 104 through the fifth solenoid valve SV5. The air storage tank 122 also includes a pressure relief port, which is connected to the fourth solenoid valve SV4, and the fourth solenoid valve SV4 is connected to the first throttle valve TV1.

[0037] In practice, the control device opens the third solenoid valve SV3 and the fifth solenoid valve SV5, and starts the positive pressure pump M1. External gas enters the air storage tank 122 after passing through the first air filter 124, the positive pressure pump M1, and the third solenoid valve SV3. Under positive pressure, the gas in the air storage tank 122 passes through the fifth solenoid valve SV5 and enters the ink supply device 104 (e.g., into the ink supply air bottle 142 or ink cartridge 146 within the ink supply device 104). The capacity of the air storage tank 122 allows for a more stable positive pressure supplied by the positive pressure providing device 102 to the ink supply device 104, thereby reducing pressure fluctuations (e.g., negative pressure fluctuations) during ink supply and printing.

[0038] The pressure value detected by the second pressure gauge AP2 reflects the pressure supplied by the positive pressure supply device 102 to the liquid supply device 104. When the pressure value detected by the second pressure gauge AP2 exceeds a predetermined positive pressure threshold, the control device controls the fourth solenoid valve SV4 to open to release air and reduce the pressure in the air storage tank 122 (that is, correspondingly reduce the pressure supplied by the positive pressure supply device 102 to the liquid supply device 104). The control device can also adjust the flow rate of the released air by adjusting the opening of the first throttle valve TV1.

[0039] The control device can be implemented using PLC (Programmable Logic Controller), MCU (Micro Controller Unit), CPU (Central Processing Unit), GPU (Graphics Processing Unit), GPGPU (General-purpose Computing on Graphics Processing Units), FPGA (Field Programmable Gate Array), and ASIC (Application Specific Integrated Circuit).

[0040] Regarding printhead 106, it is configured to eject the liquid to be printed. Printhead 106 includes, for example, ink cartridge 146 (…). Figure 2 A schematic diagram of an ink cartridge 146 according to an embodiment of this disclosure is shown. For ease of explanation, the diagram shows structures such as the X-axis and Z-axis, the nozzle, and the nozzle drive mechanism. The ink cartridge 146 is connected to the nozzle and is used to supply ink to the nozzle. During the printing process, the nozzle ejects the liquid to be printed under the drive of the printing drive mechanism. The specific shapes and connection methods of the ink cartridge 146, nozzle, nozzle drive mechanism, and other structures in the printhead 106 are readily apparent to those skilled in the art and will not be described further here.

[0041] In some embodiments, the ink cartridge 146 is provided with a longitudinal surge protection baffle 151 and a floating device 154 that floats on the surface of the liquid to be printed within its receiving cavity. Figure 4 A schematic diagram of a longitudinal surge protector 151 according to an embodiment of the present disclosure is shown, with the Y-axis and Z-axis directions shown for clarity. The longitudinal surge protector 151, for example, divides the receiving cavity of the ink cartridge 146 into a first sub-cavity 152 and a second sub-cavity 153. An opening 155 is provided at the upper part of the longitudinal surge protector 151, connecting the first sub-cavity 152 and the second sub-cavity 153. In some embodiments, the longitudinal surge protector 151 is also provided with a plurality of through holes 155. The plurality of through holes 155 are arranged in multiple rows from top to bottom, for example, with a plurality of transversely arranged through holes 155 in each row. Figure 3 A schematic diagram of the structure of an ink cartridge 146 according to an embodiment of the present disclosure is shown. For ease of explanation, the X-axis and Z-axis directions are shown in the figure. In some embodiments, such as Figure 3 As shown, adjacent rows of through holes are staggered. In other embodiments, multiple through holes 155 are arranged in a matrix. During the movement of the nozzle 106, the longitudinal anti-surge baffle 151 can effectively suppress fluctuations on the surface of the liquid to be printed and suppress the occurrence of surge phenomena.

[0042] The floating device 154 floats on the surface of the liquid to be printed. During the movement of the printhead 106, it can effectively suppress the fluctuation of the surface of the liquid to be printed and suppress the occurrence of surge phenomenon.

[0043] In some embodiments, a liquid level detection device (e.g., a level gauge) is also provided within the ink cartridge 146. This device can detect the liquid level value at a target location within the ink cartridge 146. During the printing process, the liquid level detection device can also determine the liquid level fluctuation based on multiple liquid level values ​​detected within a predetermined time period. The liquid level fluctuation is the difference between the highest and lowest liquid level values ​​of the liquid to be printed in the ink cartridge within the predetermined time period. For example, the liquid level detection device acquires the liquid level value (i.e., sampled value) at the target location at a predetermined frequency. Multiple liquid level values ​​can be detected within the predetermined time period, and the difference between the maximum value (i.e., the highest liquid level value) and the minimum value (the lowest liquid level value) is defined as the liquid level fluctuation. The liquid level fluctuation reflects the severity of the liquid level fluctuation.

[0044] In some embodiments, the nozzle 106 is provided with a water-cooling pipe and a heat sink. The water-cooling pipe and the heat sink are arranged, for example, on the outer surface of the nozzle 106, and the water-cooling pipe has a water inlet, a cooling pipe, and a water outlet.

[0045] Regarding the liquid supply device 104, which is connected to the printhead 106, it is configured to contain the liquid to be printed. The liquid supply device 104 includes, for example, an ink supply air bottle 142, an ink supply ink bottle 144, and an eighth solenoid valve SV8. The liquid supply device 104 also includes, for example, a main liquid reservoir 141, a liquid supply pump M3, and a degassing device. The main liquid reservoir 141 is connected to a return liquid device 108 and is configured to return the liquid to be printed that has flowed back through the return liquid device 108 to the main liquid reservoir 108. The liquid supply pump M3 is connected to the main liquid reservoir and is configured to allow the liquid to be printed in the main liquid reservoir 141 to enter the degassing device. The degassing device is connected to the printhead 106 and is configured to degas the flowing liquid to be printed so that it can enter the printhead 106. In some embodiments, the degassing device is connected to the printhead 106 via the ink supply ink bottle 144 and the eighth solenoid valve SV8. The liquid supply pump M3 is, for example, a peristaltic pump.

[0046] The degassing device includes, for example, a degassing lung 148 and a lung negative pressure generating device 149. The inlet of the degassing lung 148 is connected to a liquid supply pump M3, the outlet of the degassing lung 148 is connected to the printhead 106, and the air outlet of the degassing lung 148 is connected to the lung negative pressure generating device 149. A control device controls the start of the liquid supply pump M3, which causes the liquid to be printed in the main liquid storage device 141 to enter the degassing lung 148 through a second air filter 145. In some embodiments, the outlet of the degassing lung 148 is connected to the printhead 106 through a first one-way valve OV1, an ink bottle 144, and an eighth solenoid valve SV8.

[0047] Figure 8A schematic diagram of a lung negative pressure generating device 149 according to an embodiment of the present disclosure is shown. The lung negative pressure generating device 149 includes, for example, an oil-water separator PV1, a first solenoid valve SV1, a negative pressure generator VG1, a second solenoid valve SV2, and a first pressure gauge AP1. In some embodiments, compressed air is separated from water vapor by the oil-water separator PV1, and the oil-water separator PV1 adjusts the pressure of the compressed air to, for example, 0.6 MPa. A control device controls the opening of the first solenoid valve SV1 and the second solenoid valve SV2, and the compressed air (positive pressure air) passes through the negative pressure generator VG1 to form negative pressure gas. The negative pressure gas is sent to the degassed lung 148 so that the liquid to be printed flowing through the degassed lung 148 is degassed. The control device receives the pressure value detected by the first pressure gauge AP1, which reflects the pressure value of the negative pressure gas generated by the negative pressure generator VG1 (i.e., the degassed negative pressure value). After the degassing negative pressure value reaches the set negative pressure target value (e.g., -80 kPa), the control device controls the first solenoid valve SV1 and the second solenoid valve SV2 to close, so that the degassing lung 148 maintains the set negative pressure target value; if the degassing negative pressure value is lower than the set negative pressure target value, and the difference between the degassing negative pressure value and the set negative pressure target value is greater than a predetermined deviation threshold, the control device controls the first solenoid valve SV1 and the second solenoid valve SV2 to open, so as to adjust the degassing negative pressure value to the set negative pressure target value.

[0048] In some embodiments, the printing apparatus 100 is provided with a plurality of (e.g., 8) printheads 106. For example, each printhead 106 corresponds to a different color of liquid to be printed. Corresponding to each printhead 106, a set of main liquid reservoir 141, degassing lung 148, and ink supply bottle 144 are respectively provided. In some embodiments, only one set of positive pressure supply device 102 and ink supply air bottle 142 may be provided, which is shared by multiple printheads 106. In some embodiments, multiple sets of positive pressure supply device 102 and ink supply air bottle 142 may be provided, each corresponding to a multiple printhead 106.

[0049] Figure 5 A schematic diagram of the structure of a printing unit 500 according to an embodiment of the present disclosure is shown. For example, the number of printheads 106 is multiple (e.g., eight), and the multiple printheads 106 constitute the printing unit 500. In the printing unit 500, the multiple printheads 106 are arranged parallel to each other along the length direction of the printheads 106. Adjacent printheads 106 along the width direction of the printheads 106 are not aligned, but there is an overlapping area (e.g., the area shown in the dashed box in the figure), while spaced-apart printheads 106 are aligned. During printing, the length that the multiple printheads 106 can cover along the length direction of the printheads 106 is L1, and the length that the multiple printheads 106 can cover along the width direction of the printheads 106 is W1.

[0050] Figure 6 A schematic diagram of the structure of a printing unit 600 according to an embodiment of the present disclosure is shown. For example, the number of printheads 106 is multiple (e.g., eight), and the multiple printheads 106 constitute the printing unit 600. In the printing unit 600, the multiple printheads 106 are arranged parallel to each other along the length direction of the printheads 106. The multiple printheads 106 are arranged in a matrix. Adjacent printheads 106 are aligned along the width direction of the printheads 106. During printing, the length that the multiple printheads 106 can cover along the length direction of the printheads 106 is L2, and the length that the multiple printheads 106 can cover along the width direction of the printheads 106 is W2.

[0051] It should be understood that, given the same nozzle specifications 106 and the same spacing, L2 > L1, W2 <W1。 Figure 7 A schematic diagram of the printing unit 600 performing printing according to an embodiment of the present disclosure is shown. During printing, the printing unit 600 moves in the direction indicated by arrow D1 to print on the object 701 to be printed. When the printing unit 600 moves to the edge of the object 701 to be printed (e.g., the position shown in the dashed box in the figure), the control device continues to control the movement of the printing unit 600 so that the printing unit 600 moves completely to the outside of the object 701 to be printed (e.g., the position shown in the solid box in the figure), and then controls the printing unit 600 to move in the reverse direction. For ease of explanation, the stroke in which the printing unit 600 moves from the position shown in the dashed box to the position shown in the solid box, and then moves in the reverse direction to the position shown in the dashed box, is called the "return stroke". It should be understood that because W2 is updated, the printing unit 600 has a smaller return stroke than the printing unit 500. Therefore, during the printing process, the printing unit 600 is advantageous in improving printing efficiency.

[0052] Regarding the liquid return device 108, it is connected to the printhead 106 and the liquid supply device 104, and is configured to allow the liquid to be printed in the printhead 106 to flow back to the liquid supply device 104. The liquid return device 108 includes, for example, a liquid return bottle 182 and a liquid return pump M4. The liquid return device 108 also includes, for example, a second one-way valve OV2, a ninth solenoid valve SV9, a return ink air bottle 184, a third pressure gauge AP3, a seventh solenoid valve SV7, and a second throttle valve TV2.

[0053] The return bottle 182 is connected to the printhead 106 and is configured to store the liquid to be printed flowing out of the printhead 106. In some embodiments, the return bottle 182 is connected to the printhead 106 via a second one-way valve OV2 and a ninth solenoid valve SV9.

[0054] The return pump M4 is connected to the return bottle 182 and the supply device 104, and is configured to generate negative pressure so that the liquid to be printed in the return bottle 182 flows back to the supply device 104. The return pump M4 is connected to the main storage device 141, for example, and generates negative pressure to cause the liquid to be printed in the return bottle 182 to flow back to the main storage device 141.

[0055] It is worth noting that the function of the return pump M4 is twofold: firstly, to pump the liquid to be printed from the return bottle 182 to the main liquid storage device 141; and secondly, to provide a negative pressure for the return device 108. The negative pressure provided by the return pump M4 can be detected by the third pressure gauge AP3.

[0056] In some embodiments, the printing equipment 100 is provided with a plurality of (e.g., eight) printheads 106. Accordingly, in the printing equipment 100, a liquid return device 108 is provided corresponding to each printhead 106. The liquid return devices 108 corresponding to each printhead 106 can operate simultaneously or in a time-sharing manner, that is, the control device can control each of the plurality of liquid return devices 108 in the printing equipment 100 individually.

[0057] In some embodiments, the printing apparatus 100 is provided with a plurality of printheads 106. The plurality of printheads 106 are respectively connected to the same liquid return device 108. That is, the liquid return control for the plurality of printheads 106 is realized by using a single liquid return device 108.

[0058] In some embodiments, a liquid level sensor (not shown) is provided in the return liquid bottle 182 for detecting the liquid level of the liquid to be printed in the return liquid bottle 182. The control device is also configured to determine whether the liquid level of the liquid to be printed in the return liquid bottle has reached a predetermined liquid level threshold, and to start the return liquid pump in response to determining that the liquid level of the liquid to be printed in the return liquid bottle has reached the predetermined liquid level threshold.

[0059] It is worth noting that the printhead 106 has an ink inlet, an ink outlet, an ink return line, and an ink return port. After the ink to be printed enters the printhead 106 through the ink inlet, a portion of the ink is ejected through the ink outlet during printing, while the remaining portion flows back to the return bottle 182 through the ink return line and the ink return port. A predetermined pressure difference exists between the ink inlet and the ink outlet of the printhead 106. The positive pressure provided by the positive pressure providing device 102 matches the predetermined pressure difference between the ink inlet and the ink outlet of the printhead 106, ensuring stable ink ejection (i.e., ink output) during printing. Stable ink ejection here should be understood as the ink volume meeting the ink ejection requirements. For example, in a stage requiring uniform ink ejection, the printhead 106 ejects ink uniformly, without insufficient or excessive ink ejection.

[0060] In some embodiments, during the printing process, the control device ensures that the difference between the positive pressure provided by the positive pressure supply device 102 and the negative pressure generated by the liquid return device 108 meets a predetermined condition. For example, the control device maintains the difference between the positive pressure provided by the positive pressure supply device 102 and the negative pressure generated by the liquid return device 108 within a predetermined range to ensure stable ink ejection from the printhead 106.

[0061] During the printing process, the control device generates control signals to adjust at least one of the pressure values ​​of the positive pressure provided by the positive pressure supply device 102 and the negative pressure generated by the liquid return device 108. For example, the control device generates a positive pressure control signal to adjust the pressure value of the positive pressure provided by the positive pressure supply device 102. The control device also generates a negative pressure control signal to adjust the pressure value of the negative pressure generated by the liquid return device 108 (e.g., the liquid return pump M4 therein).

[0062] The control device generates a control signal based on at least one of the following (in order to adjust at least one of the pressure values ​​of the positive pressure provided by the positive pressure providing device 102 and the pressure values ​​of the negative pressure generated by the return device 108): the movement speed of the nozzle, the spray rate of the nozzle, and the ambient temperature.

[0063] For example, the control device generates a corresponding positive pressure control signal based on the movement speed of the nozzle 106, so that the pressure value of the positive pressure provided by the positive pressure providing device 102 is adapted to the movement speed of the nozzle 106. For example, the control device makes the pressure value of the positive pressure provided by the positive pressure providing device 102 positively correlated with the movement speed of the nozzle 106; that is, the greater the movement speed of the nozzle 106, the greater the pressure value of the positive pressure provided by the positive pressure providing device 102. The movement speed of the nozzle 106 can be detected by a speed sensor installed at the nozzle 106.

[0064] For example, the control device generates a corresponding positive pressure control signal based on the printhead's spray rate, so that the pressure value of the positive pressure provided by the positive pressure providing device 102 is adapted to the printhead's spray rate. The spray rate is characterized, for example, by the average spray volume per unit time. The printhead's spray rate is, for example, the target spray rate required to achieve a predetermined printing effect. For example, the control device makes the pressure value of the positive pressure provided by the positive pressure providing device 102 positively correlated with the printhead's spray rate; that is, the greater the printhead's spray rate, the greater the pressure value of the positive pressure provided by the positive pressure providing device 102.

[0065] For example, the control device generates a corresponding positive pressure control signal based on the ambient temperature, so that the pressure value of the positive pressure provided by the positive pressure providing device 102 is adapted to the ambient temperature. For instance, the pressure value of the positive pressure provided by the positive pressure providing device 102 is negatively correlated with the ambient temperature; that is, the higher the ambient temperature, the lower the pressure value of the positive pressure provided by the positive pressure providing device 102. It is worth noting that the fluidity of the liquid to be printed is related to the ambient temperature; the higher the ambient temperature, the better the fluidity of the liquid to be printed, and therefore, the pressure value of the positive pressure provided by the positive pressure providing device 102 can be correspondingly lower.

[0066] It should be understood that the control device can also generate corresponding positive pressure control signals based on at least two of the following: the nozzle's movement speed, the nozzle's liquid spraying rate, and the ambient temperature, in order to precisely control the printing effect.

[0067] For example, the control device generates a corresponding negative pressure control signal based on the movement speed of the nozzle 106, so that the pressure value of the negative pressure generated by the return liquid device 108 (e.g., the return liquid pump M4 therein) is adapted to the movement speed of the nozzle 106. For example, the control device makes the pressure value of the negative pressure generated by the return liquid device 108 positively correlated with the movement speed of the nozzle 106, that is, the greater the movement speed of the nozzle 106, the greater the pressure value of the negative pressure generated by the return liquid device 108.

[0068] For example, the control device generates a corresponding negative pressure control signal based on the spray rate of the nozzle, so that the pressure value of the negative pressure generated by the return device 108 is adapted to the spray rate of the nozzle. For example, the control device makes the pressure value of the negative pressure generated by the return device 108 positively correlated with the spray rate of the nozzle, that is, the greater the spray rate of the nozzle, the greater the pressure value of the negative pressure generated by the return device 108.

[0069] For example, the control device generates a corresponding negative pressure control signal based on the ambient temperature, so that the pressure value of the negative pressure generated by the liquid return device 108 is adapted to the ambient temperature. For instance, the pressure value of the negative pressure generated by the liquid return device 108 is negatively correlated with the ambient temperature; that is, the higher the ambient temperature, the lower the pressure value of the negative pressure generated by the liquid return device 108. It is worth noting that the fluidity of the liquid to be printed is related to the ambient temperature; the higher the ambient temperature, the better the fluidity of the liquid to be printed, and therefore, the lower the pressure value of the negative pressure generated by the liquid return device 108 can be accordingly.

[0070] It should be understood that the control device can also generate corresponding negative pressure control signals based on at least two of the printhead's movement speed, printhead's ink spraying rate, and ambient temperature, in order to precisely control the printing effect and ink return effect.

[0071] In some embodiments, the control device is further configured to determine an S-curve speed profile based on the length of the object to be printed and a target production capacity, and to control the printhead movement based on the S-curve speed profile. The target production capacity is characterized, for example, by the total length (or total area) of the object to be printed within a predetermined production cycle, or by the total length (or total area) of the object to be printed per unit time. It should be understood that the total length (or total area) of the object to be printed per unit time can be characterized as the ratio of the total length (or total area) of the object to be printed within a predetermined production cycle to the predetermined production cycle. Determining the S-curve speed profile based on the length of the object to be printed and the target production capacity can effectively improve printing efficiency (e.g., printing output per unit time).

[0072] Figure 9 A schematic diagram of an S-shaped velocity curve of an embodiment of the present disclosure is shown, wherein the horizontal axis represents time (t) and the vertical axis represents the velocity (v) of the nozzle 106. Figure 10 A schematic diagram of the printing stroke according to an embodiment of the present disclosure is shown. The S-shaped speed curve is generated by a control device based on the length of the object to be printed and the target production capacity. Using this S-shaped speed curve, the single printing stroke of the printhead 106 (e.g., the printing unit 600 therein) is divided into seven stages. A single printing stroke is, for example, the stroke traveled by the printhead 106 during the printing process from one side of the object to be printed 701 (e.g., at the first position P1) to the other side (e.g., at the second position P2) of the object to be printed. It should be understood that completing the printing of the object to be printed requires performing one or more single printing strokes. The seven stages of a single printing stroke include an acceleration stage T1, a uniform acceleration stage T2, a deceleration stage T3, a constant speed stage T4, an acceleration / deceleration stage T5, a uniform deceleration stage T6, and a deceleration / deceleration stage T7. It should be understood that the speeds of adjacent stages are continuously connected, and the rate of change of acceleration is controllable.

[0073] In some embodiments, the control device is further configured to adjust the S-shaped speed curve based on the level fluctuation of the liquid to be printed in the ink cartridge. As mentioned earlier, the level fluctuation is the difference between the highest and lowest liquid level values ​​of the liquid to be printed in the ink cartridge within a predetermined time period. It is worth noting that the level fluctuation reflects the severity of the fluctuation in the liquid to be printed in the ink cartridge during the printing process. Excessive level fluctuation can affect the pressure at the ink outlet of the printhead 106 (e.g., the ink outlet of the nozzle), thereby impacting the printing effect. Adjusting the S-shaped speed curve based on the level fluctuation of the liquid to be printed in the ink cartridge is a comprehensive adjustment of the movement state of the printhead 106 throughout the entire single printing stroke. This effectively reduces the level fluctuation of the liquid to be printed in the ink cartridge, ensuring both printing effect and printing efficiency.

[0074] In some embodiments, as a real-time adjustment strategy, when the liquid level fluctuation exceeds a predetermined fluctuation threshold, the control device correspondingly reduces the movement speed of the nozzle 106.

[0075] Figure 10 A schematic diagram of the cleaning apparatus 103 according to an embodiment of the present disclosure is shown. The cleaning apparatus 103 includes, for example, a cleaning positive pressure pump M2 and a cleaning valve SV6, with the cleaning positive pressure pump M2 connected to the nozzle 106 via the cleaning valve SV6. The cleaning positive pressure pump M2 is also connected to the nozzle 106, for example, via the cleaning valve SV6, a liquid supply air bottle 142, and a liquid supply bottle 144. The cleaning apparatus 103 may also include a third air filter 132.

[0076] When nozzle 106 becomes clogged, the control device initiates the cleaning procedure. First, the control device closes the fifth solenoid valve SV5, and also closes the eighth solenoid valve SV8 and the ninth solenoid valve SV9. Then, the control device opens the cleaning valve SV6 and the cleaning positive pressure pump M2, which supplies positive pressure gas to the liquid supply air bottle 142. It should be understood that the positive pressure gas supplied by the cleaning positive pressure pump M2 also enters the liquid supply bottle 144. The fourth pressure gauge AP4 monitors the pressure of the positive pressure gas supplied by the cleaning positive pressure pump M2 in real time (e.g., the fourth pressure gauge AP4 monitors the pressure of the liquid supply air bottle 142 in real time to obtain the pressure of the positive pressure gas supplied by the cleaning positive pressure pump M2). The control device determines whether the pressure of the positive pressure gas provided by the cleaning positive pressure pump M2 reaches a predetermined cleaning pressure threshold (e.g., 60 kPa) based on the pressure detected by the fourth pressure gauge AP4. If the control device determines that the pressure of the positive pressure gas provided by the cleaning positive pressure pump M2 reaches the predetermined cleaning pressure threshold, it opens the eighth solenoid valve SV8 so that the ink to be printed is ejected under the pressure of the positive pressure gas provided by the cleaning positive pressure pump M2, thereby clearing the blocked ink outlet. Then, after a predetermined cleaning time (e.g., several seconds), the control device controls the ninth solenoid valve SV9 to open and activates the liquid return device 108 so that any air present in the printhead 106 can be discharged through the liquid return device 108. Then, the control device controls the cleaning valve SV6 and the cleaning positive pressure pump M2 to close. When the pressure detected by the fourth pressure gauge AP4 drops to 0 kPa, the control device opens the fifth solenoid valve SV5 and starts the positive pressure supply device 102 and the liquid return device 108, so that the positive pressure provided by the positive pressure supply device 102 meets the predetermined positive pressure range, and the negative pressure generated by the liquid return device 108 meets the predetermined negative pressure range, so as to perform printing.

[0077] The various embodiments of this disclosure have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or technical improvements to the embodiments in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

[0078] The above are merely optional embodiments of this disclosure and are not intended to limit this disclosure. Various modifications and variations can be made to this disclosure by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this disclosure should be included within the scope of protection of this disclosure.

Claims

1. A jet printing apparatus characterized by comprising: The inkjet printing device comprises: a positive pressure providing device, which is in communication with the liquid supply device and is configured to provide a positive pressure to the liquid supply device so that the liquid to be jetted in the liquid supply device enters the nozzle under the action of the positive pressure; the liquid supply device, which is in communication with the nozzle and is configured to contain the liquid to be jetted; the nozzle, which is configured to jet the liquid to be jetted; and the liquid return device, which is in communication with the nozzle and the liquid supply device and is configured to make the liquid to be jetted in the nozzle return to the liquid supply device; the inkjet printing device further comprises a control device, which is configured to determine an S-shaped speed curve according to the length of the object to be jetted and the target productivity, and control the movement of the nozzle according to the S-shaped speed curve; the nozzle comprises an ink cartridge, which comprises a containing cavity for containing the liquid to be jetted; the control device is further configured to adjust the S-shaped speed curve according to the fluctuation amount of the liquid level of the liquid to be jetted in the ink cartridge, the fluctuation amount being the difference between the highest liquid level value and the lowest liquid level value of the liquid to be jetted in the ink cartridge within a predetermined time period.

2. The inkjet printing device according to claim 1, wherein the control device is further configured to adjust the pressure value of the positive pressure provided by the positive pressure providing device according to at least one of the following: the movement speed of the nozzle; the liquid jetting rate of the nozzle; and the ambient temperature.

3. The printing apparatus according to claim 1, wherein The positive pressure providing device comprises: a positive pressure pump, which is in communication with the gas storage tank and is configured to deliver the positive pressure gas to the gas storage tank; and the gas storage tank, which is in communication with the liquid supply device so that the positive pressure gas enters the liquid supply device to exert a positive pressure on the liquid to be jetted.

4. The printing apparatus of claim 1, wherein The containing cavity of the ink cartridge is provided with a longitudinal anti-surge partition plate and a floating device floating on the surface of the liquid to be jetted.

5. The printing apparatus of claim 1, wherein The nozzle is provided with a water-cooling pipe and a heat sink.

6. The printing apparatus of claim 1, wherein The number of nozzles is multiple, and the multiple nozzles are arranged in a matrix.

7. The printing apparatus of claim 1, wherein The liquid supply device further comprises: a main liquid storage device, which is in communication with the liquid return device and is configured to return the liquid to be jetted returned by the liquid return device to the main liquid storage device; a liquid supply pump, which is in communication with the main liquid storage device and is configured to make the liquid to be jetted in the main liquid storage device enter the degassing device; and the degassing device, which is in communication with the nozzle and is configured to degas the liquid to be jetted flowing therethrough so as to enter the nozzle.

8. The printing apparatus of claim 1, wherein, The inkjet printing device further comprises a cleaning device, and the control device is further configured to turn off the positive pressure providing device and start the cleaning device to clean the nozzle.

9. The printing apparatus of claim 2, wherein The liquid return device comprises: a liquid return bottle, which is in communication with the nozzle and is configured to store the liquid to be jetted flowing out of the nozzle; and a liquid return pump, which is in communication with the liquid return bottle and the liquid supply device and is configured to generate a negative pressure to make the liquid to be jetted in the liquid return bottle return to the liquid supply device.

10. The printing apparatus of claim 9, wherein, The control device is further configured to determine whether the liquid level of the liquid to be jetted in the liquid return bottle reaches a predetermined liquid level threshold, and start the liquid return pump in response to determining that the liquid level of the liquid to be jetted in the liquid return bottle reaches the predetermined liquid level threshold.

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