Ink-jet printer nozzle negative pressure control method, system, equipment and medium

Abstract

The invention provides an ink-jet printer nozzle negative pressure control method, system and device and a medium, and relates to the technical field of ink-jet printer control. The method comprises the following steps: calculating an estimated required ink amount according to a preset ink supplementing negative pressure threshold value and a minimum ink supplementing negative pressure; according to the number of the obtained pixel points of the printed image, the actual estimated code spraying amount is calculated; when the actual estimated code spraying amount reaches the estimated required ink amount, ink supplementing is triggered, the code spraying amount is converted into the target stepping number of the stepping motor, the actual stepping number of the stepping motor is obtained by combining the air pressure detection value obtained in real time and inputting the air pressure detection value into the PI D control model, and therefore operation of the stepping motor is controlled, an ink supplementing pump is driven to convey ink, and quantitative ink supplementing of the ink-jet printer is achieved. According to the invention, the negative pressure in the nozzle cavity is always kept within a certain deviation range, and the problem that the ink-jet printer cannot perform normal ink-jet printing due to excessive ink supplementation or untimely ink supplementation of the ink-jet printer caused by the influence of hysteresis of a machine structure, sensor precision, reaction time and the like in the existing ink-jet printer control method is solved.

Description

Technical Field

[0001] The present invention relates to the field of inkjet printer control technology, and in particular to a method, system, equipment and medium for controlling negative pressure of an inkjet printer nozzle. Background Art

[0002] Industrial inkjet printers use piezoelectric nozzles for inkjet printing. Usually, it is necessary to maintain a certain negative pressure range in the nozzle pipeline cavity so that the ink can flow out naturally without being affected by gravity due to surface tension and negative pressure. If the negative pressure in the nozzle pipeline cavity is too large, it will cause insufficient ink supply and ink interruption, and the inkjet quality will be easily affected and unable to be sprayed; if the negative pressure is too small, the ink will flow out naturally due to gravity. Therefore, it is necessary to maintain a certain pressure range in the nozzle ink cavity.

[0003] The traditional method is to detect the negative pressure sensor through the controller. When the negative pressure decreases to a certain threshold, the ink is drawn to replenish the ink until the value of the negative pressure sensor reaches another threshold and then the pump stops working. However, since it takes a certain amount of time for the pump to drive the air pressure change, there is a hysteresis problem in the structure. In addition, due to the influence of the accuracy and reaction time of the sensor, it may cause excessive ink replenishment or untimely ink replenishment, thus affecting normal inkjet printing.

[0004] In view of this, the applicant filed this application after studying the existing technology. Summary of the invention

[0005] The present invention aims to provide a method, system, device and medium for controlling the negative pressure of a printer nozzle, so as to solve the problem in the existing method that excessive ink replenishment or untimely ink replenishment and normal ink jetting cannot be caused by the influence of machine structure hysteresis, sensor accuracy, reaction time, etc.

[0006] In order to solve the above technical problems, the present invention is implemented through the following technical solutions:

[0007] A method for controlling the negative pressure of a printer nozzle is applied to a printer using a stepper motor to drive an ink filling pump, comprising:

[0008] According to the preset ink replenishing negative pressure threshold and the minimum ink replenishing negative pressure, the amount of ink required for the negative pressure of the pipeline cavity at the nozzle point to change from the ink replenishing negative pressure threshold to the minimum ink replenishing negative pressure is obtained, that is, the estimated required ink amount;

[0009] Obtain the number of pixels of the printed image, and calculate the actual estimated inkjet volume based on the unit inkjet volume of each nozzle point and the number of pixels of the printed image;

[0010] When the actual estimated inkjet printing amount reaches the estimated required ink amount, the actual estimated inkjet printing amount is converted into the number of steps required by the stepping motor, that is, the target number of steps, according to the unit stepping ink amount of the inkjet printer;

[0011] The air pressure detection value of the air pressure sensor of the inkjet printer is obtained in real time, the target step number and the air pressure detection value are input into the PID control model, the actual step number of the stepper motor is output, and the operation of the stepper motor is controlled according to the actual step number to drive the ink replenishing pump to transport ink and reset the number of pixels of the printed image.

[0012] Preferably, the maximum negative pressure of the inkjet printer is defined as P max , the minimum negative pressure is P min , the ink filling negative pressure threshold is P m , the minimum negative pressure for ink filling is P j , then |P max |>|P m |>|P j |>|P min |; wherein the ink replenishing negative pressure threshold is the negative pressure threshold at which the pump starts to replenish ink; and the minimum ink replenishing negative pressure is the actual minimum negative pressure of ink replenishing.

[0013] Preferably, the actual estimated coding amount V total The calculation formula is:

[0014] V total =N×V dot ;

[0015] Where N is the number of pixels of the printed image; V dot It is the unit inkjet volume of each nozzle point of the inkjet printer.

[0016] Preferably, the target step number N steps The calculation formula is:

[0017] N steps =V total ÷V step ;

[0018] Among them, V step The unit stepping ink volume is the amount of ink pressed when the stepping motor takes one step.

[0019] Preferably, the expression of the PID control model is as follows:

[0020] N rsteps =N steps (K p ×P Deta +K i ×P Integ +K d ×P DDeta );

[0021] P Deta =P cur -P m ;

[0022] P Integ =∑(P cur -P m );

[0023] P DDeta =P Deta -P PreDeta ;

[0024] Among them, N rsteps is the actual number of steps; K p , K i , K d is the adjustment parameter of the PID control model; cur The negative pressure of the current air pressure detection value obtained; P Deta is the current air pressure detection value P cur and ink filling threshold P m The error value of P Integ is the cumulative error value; P Deta P cur With P m The error value of P Integ is the cumulative error value; P PreDeta is the error value of the last ink filling; P DDeta is the error change rate, that is, the current error value P Deta The error value P of the last time PreDeta difference.

[0025] The present invention also provides a negative pressure control system for a printer nozzle, comprising:

[0026] The required ink volume estimation module is used to obtain the ink volume required for the negative pressure of the pipeline cavity at the nozzle point to change from the ink replenishment negative pressure threshold to the minimum ink replenishment negative pressure according to the preset ink replenishment negative pressure threshold and the minimum ink replenishment negative pressure, that is, to estimate the required ink volume;

[0027] The coding volume calculation module is used to obtain the number of pixels of the printed image and calculate the actual estimated coding volume based on the unit inkjet volume of each nozzle point and the number of pixels of the printed image;

[0028] A target step number conversion module is used to convert the actual estimated inkjet amount into the step number required by the stepping motor, i.e., the target step number, according to the unit step ink amount of the inkjet printer when the actual estimated inkjet amount reaches the estimated required ink amount;

[0029] The ink replenishment module is used to obtain the air pressure detection value of the air pressure sensor of the inkjet printer in real time, input the target step number and the air pressure detection value into the PID control model, output the actual step number of the stepper motor, and control the operation of the stepper motor according to the actual step number to drive the ink replenishment pump to transport ink and reset the number of pixels of the printed image.

[0030] The present invention also provides a negative pressure control device for a printer nozzle, comprising a processor and a memory, wherein the memory stores a computer program, and the computer program can be executed by the processor to implement a negative pressure control method for a printer nozzle as described above.

[0031] The present invention also provides a computer-readable storage medium, on which computer-readable instructions are stored. When the computer-readable instructions are executed by a processor of a device where the computer-readable storage medium is located, a method for controlling the negative pressure of a printer nozzle as described above is implemented.

[0032] In summary, compared with the prior art, the present invention has the following beneficial effects:

[0033] The present invention converts the calculation of the ink replenishment amount into the calculation of the step number of the stepping motor through the relationship between the ink amount and the step number of the stepping motor, and realizes accurate replenishment of the ink amount through precise control of the stepping motor.

[0034] The present invention is based on the PID control algorithm, which integrates the air pressure detection value of the air pressure sensor obtained in real time with the calculated theoretical target step number to give a more accurate step number. The pump operation is controlled by a stepping motor to drive the ink replenishing pump to deliver ink, so that the negative pressure in the nozzle cavity is always maintained within a certain deviation range, thereby solving the problem that the existing inkjet printer control method is affected by the hysteresis of the machine structure, sensor accuracy, response time, etc., resulting in excessive ink replenishment or untimely ink replenishment and failure to spray normally. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0036] Figure 1 A schematic diagram of a method for controlling negative pressure of a printer nozzle provided in Embodiment 1 of the present invention.

[0037] Figure 2 A schematic diagram of a negative pressure control system for a printer nozzle provided in Embodiment 2 of the present invention.

[0038] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the invention claimed for protection, but merely represents the selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0040] Embodiment 1

[0041] Embodiment 1 of the present invention provides a method for controlling the negative pressure of a printer nozzle, which can be implemented by a negative pressure control device for a printer nozzle (hereinafter referred to as the negative pressure control device), and in particular, executed by one or more processors in the negative pressure control device.

[0042] In this embodiment, the negative pressure control device can be a printer equipped with a processor, wherein, during the printing process of the printer nozzle, the negative pressure in the pipeline cavity (negative pressure refers to the gas pressure state lower than the standard atmospheric pressure, the reference point is atmospheric pressure, indicating the difference between the air pressure and the atmospheric pressure, and the negative pressure in this embodiment refers to the difference between the air pressure in the pipeline cavity and the atmospheric pressure) is in the process of increasing. At this time, a pump is needed to extract ink and send the ink to the ink cavity where the nozzle is located to reduce its negative pressure, thereby maintaining a certain range of pressure in the nozzle pipeline cavity. The amount of ink drawn by the pump to be replenished in the nozzle cavity is called the ink replenishment amount. The usual practice is to extract ink and replenish it into the nozzle ink cavity when the negative pressure is reduced to a certain threshold until it reaches a certain negative pressure value. However, if the pump is dynamically controlled to replenish ink by relying solely on the air pressure sensor, it will be affected by the accuracy of the sensor, the reaction time and the hysteresis problem existing in the structure of the printer, resulting in the problem of excessive ink replenishment or untimely ink replenishment of the printer. Excessive ink replenishment will cause the actual negative pressure to be low, resulting in ink hanging problems; and untimely ink replenishment will result in insufficient ink in the nozzle cavity. Both of these situations will cause the inkjet printer to be unable to print normally.

[0043] For this reason, Figure 1As shown, the first embodiment of the present invention provides a method for controlling the negative pressure of a printer nozzle, which is applied to a printer that uses a stepper motor to drive an ink replenishing pump, and includes steps S1 to S4.

[0044] S1, according to the preset ink replenishing negative pressure threshold and the minimum ink replenishing negative pressure, the amount of ink required for the negative pressure of the pipeline cavity at the nozzle point to change from the ink replenishing negative pressure threshold to the minimum ink replenishing negative pressure, that is, the estimated required ink amount.

[0045] In this embodiment, the inkjet printer includes a nozzle, a pump, a stepper motor, an air pressure sensor and a controller, etc.; wherein, the nozzle is responsible for spraying ink in the form of fine particles onto the printing paper to form an image or text; the pump is used to store ink for use by the nozzle; the stepper motor is used to drive the pump to transport ink; the air pressure sensor is used to detect the air pressure value of the pipeline cavity inside the nozzle.

[0046] First, obtain the specification data of the current inkjet printer, wherein the specification data of the inkjet printer includes the unit inkjet volume of each nozzle point, the maximum value of the nozzle negative pressure, the minimum value of the nozzle negative pressure and the specification data of the pump.

[0047] In this embodiment, the ink filling negative pressure threshold and the minimum ink filling negative pressure of the inkjet printer are preset according to the maximum value and the minimum value of the nozzle negative pressure.

[0048] Preferably, the maximum negative pressure is defined as P max , the minimum negative pressure is P min , the ink filling negative pressure threshold is P m , the minimum negative pressure for ink filling is P j .

[0049] In this embodiment, the ink replenishing negative pressure threshold P m The negative pressure threshold for the pump to start filling ink is usually taken as the negative pressure threshold for filling ink. j is the minimum negative pressure of the actual ink filling setting, which is the ratio of P min A slightly larger value satisfies:

[0050] |P max |>|P m |>|P j |>|P min |.

[0051] Then, according to the preset ink replenishing negative pressure threshold and the minimum ink replenishing negative pressure, the amount of ink required for the negative pressure of the pipeline cavity at the nozzle point to change from the ink replenishing negative pressure threshold to the minimum ink replenishing negative pressure is obtained, that is, the estimated required ink amount.

[0052] In this embodiment, the ink filling negative pressure threshold P can be calculated by historical data or the actual measured air pressure. m To the minimum ink filling negative pressure Pj Required ink volume V w .

[0053] S2, obtaining the number of pixels of the printed image, and calculating the actual estimated inkjet volume according to the unit inkjet volume of each nozzle point and the number of pixels of the printed image.

[0054] In this embodiment, the unit ink jetting amount of each nozzle point is the expected output ink amount when each nozzle point performs an ink jetting action, which is determined by the specifications of the inkjet printer nozzle. Since there may be a deviation between the unit ink jetting amount of each nozzle point and the actual output ink amount during the actual inkjet printing process, the deviation may also cause excessive ink replenishment or untimely ink replenishment after multiple accumulations. This embodiment adjusts the actual ink replenishment process by combining quantitative ink replenishment and PID control, which can effectively reduce the impact caused by the deviation.

[0055] In this embodiment, the number of pixels of the printed image is the number of pixels of the image that has been printed and to be filled with ink.

[0056] Furthermore, the actual estimated coding volume V total The calculation formula is:

[0057] V total =N×V dot ;

[0058] Where N is the number of pixels of the printed image; V dot It is the unit inkjet volume of each nozzle point of the inkjet printer.

[0059] S3, when the actual estimated inkjet printing amount reaches the estimated required ink amount, the actual estimated inkjet printing amount is converted into the number of steps required by the stepping motor, that is, the target number of steps, according to the unit stepping ink amount of the inkjet printer.

[0060] In this embodiment, when the actual estimated inkjet coding volume reaches the estimated required ink volume, the ink replenishment process is triggered and the ink replenishment processing process is entered.

[0061] Furthermore, the target step number N steps The calculation formula is:

[0062] N steps =V total ÷V step ;

[0063] Among them, V step The unit stepping ink volume is the amount of ink pressed when the stepping motor takes one step.

[0064] In this embodiment, based on the specification data of the pump, such as the pump diameter, the step distance of the stepper motor and the working efficiency of the pump, the amount of ink required for the stepper motor to move one step, that is, the unit step ink amount, can be obtained; it can also be determined through experiments or by referring to the specification sheet of the pump, which will not be repeated here.

[0065] S4, obtains the air pressure detection value of the air pressure sensor of the inkjet printer in real time, inputs the target step number and the air pressure detection value into the PID control model, outputs the actual step number of the stepper motor, and controls the operation of the stepper motor according to the actual step number to drive the ink replenishing pump to transport ink and reset the number of pixels of the printed image.

[0066] Furthermore, the PID control model takes P m As an intermediate value for reference, the expression of the PID control model is as follows:

[0067] N rsteps =N steps (K p ×P Deta +K i ×P Integ +K d ×P DDeta );

[0068] P Deta =P cur -P m ;

[0069] P Integ =∑(P cur -P m );

[0070] P DDeta =P Deta -P PreDeta ;

[0071] Among them, N rsteps is the actual number of steps; K p , K i , K d is the adjustment parameter of the PID control model; cur The negative pressure of the current air pressure detection value obtained; P Deta is the current air pressure detection value P cur and ink filling threshold P m The error value of P Integ is the cumulative error value; P PreDeta is the error value of the last ink filling; P DDeta is the error change rate, that is, the current error value P Deta The error value P of the last time PreDeta difference.

[0072] In this embodiment, the PID control model is a feedback control system that calculates the output of the controller by comparing the error between the system's set value (i.e., target value) and the actual output value (i.e., feedback value), thereby adjusting the system to make the actual output value as close to the set value as possible. PID control consists of three parts: proportional (P), integral (I), and differential (D).

[0073] Proportional part (P): According to the error value, a certain proportion (i.e. K p ) to adjust the output. The larger the error, the larger the adjustment.

[0074] Integral part (I): Accumulate the errors in the past period of time and convert them into a certain proportion (i.e. K i ) adjusts the output to eliminate the steady-state error of the system.

[0075] Derivative part (D): According to the rate of change of error (that is, the difference between the current error and the previous error, that is, P DDeta ), with a certain ratio (i.e. K d ) to adjust the output. It is used to predict the trend of future error changes, speed up system response and reduce overshoot and oscillation.

[0076] After calculating the actual number of steps of the stepper motor, the operation of the stepper motor is controlled according to the actual number of steps to drive the ink replenishing pump to deliver ink, realize the quantitative ink replenishment of the inkjet printer, reset the number of pixels of the printed image, and continue the next ink replenishment operation.

[0077] In this embodiment, P max , P min , P m , P j , P cur , P Deta , P DDeta , P PreDeta , P Integ All are expressed as negative pressure.

[0078] In summary, compared with the prior art, the present invention has the following beneficial effects:

[0079] The present invention converts the calculation of the ink replenishment amount into the calculation of the step number of the stepper motor through the relationship between the ink amount and the step number of the stepper motor, and realizes the accurate replenishment of the ink amount through the precise control of the stepper motor. Based on the PID control algorithm, the present invention integrates the air pressure detection value of the air pressure sensor acquired in real time with the calculated theoretical target step number to give a more accurate step number, and controls the operation of the pump through the stepper motor so that the negative pressure in the nozzle cavity is always maintained within a certain deviation range, thereby solving the problem that the existing inkjet printer control method is affected by the hysteresis of the machine structure, the accuracy of the sensor, the reaction time, etc., causing the inkjet printer to replenish ink excessively or replenish ink untimely and fail to spray normally.

[0080] Embodiment 2

[0081] like Figure 2 As shown, the second embodiment of the present invention further provides a printer nozzle negative pressure control system, comprising:

[0082] The required ink volume estimation module is used to obtain the ink volume required for the negative pressure of the pipeline cavity at the nozzle point to change from the ink replenishment negative pressure threshold to the minimum ink replenishment negative pressure according to the preset ink replenishment negative pressure threshold and the minimum ink replenishment negative pressure, that is, to estimate the required ink volume;

[0083] The coding volume calculation module is used to obtain the number of pixels of the printed image and calculate the actual estimated coding volume based on the unit inkjet volume of each nozzle point and the number of pixels of the printed image;

[0084] A target step number conversion module is used to convert the actual estimated inkjet amount into the step number required by the stepping motor, i.e., the target step number, according to the unit step ink amount of the inkjet printer when the actual estimated inkjet amount reaches the estimated required ink amount;

[0085] The ink replenishment module is used to obtain the air pressure detection value of the air pressure sensor of the inkjet printer in real time, input the target step number and the air pressure detection value into the PID control model, output the actual step number of the stepper motor, and control the operation of the stepper motor according to the actual step number to drive the ink replenishment pump to transport ink and reset the number of pixels of the printed image.

[0086] Embodiment 3

[0087] The third embodiment of the present invention also provides a device for controlling the negative pressure of a printer nozzle, which includes a memory and a processor. The memory stores a computer program, and the computer program can be executed by the processor to implement the negative pressure control method of the printer nozzle as described above.

[0088] Embodiment 4

[0089] The fourth embodiment of the present invention also provides a computer-readable storage medium, on which computer-readable instructions are stored. When the computer-readable instructions are executed by the processor of the device where the computer-readable storage medium is located, the negative pressure control method of the inkjet printer nozzle as described above is implemented.

[0090] In several embodiments provided in the embodiments of the present invention, it should be understood that the disclosed apparatus and method can also be implemented in other ways. The apparatus and method embodiments described above are merely schematic. For example, the flowcharts in the accompanying drawings show the possible architecture, functions and operations of the apparatus, method and computer program product according to multiple embodiments of the present invention. In this regard, each box in the flowchart or block diagram can represent a module, a program segment or a part of a code, and the module, program segment or a part of the code contains one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in a different order from the order marked in the accompanying drawings. For example, two consecutive boxes can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram and / or flow chart, and the combination of boxes in the block diagram and / or flow chart can be implemented with a dedicated hardware-based system that performs a specified function or action, or can be implemented with a combination of dedicated hardware and computer instructions.

[0091] In addition, the functional modules in the various embodiments of the present invention may be integrated together to form an independent part, or each module may exist independently, or two or more modules may be integrated to form an independent part.

[0092] If the functions are implemented in the form of software function modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on such an understanding, the technical solution of the present invention is essentially or the part that contributes to the prior art or the part of the technical solution can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions to enable a computer device (which can be a personal computer, an electronic device, or a network device, etc.) to perform all or part of the steps of the methods described in various embodiments of the present invention. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk. It should be noted that, in this article, the terms "include", "comprise" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements that are not explicitly listed, or also includes elements inherent to such a process, method, article or device. Without more constraints, an element defined by the phrase "comprising a..." does not exclude the existence of other identical elements in the process, method, article or apparatus comprising the element.

[0093] The terms used in the embodiments of the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. The singular forms "a", "said" and "the" used in the embodiments of the present invention and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

[0094] It should be understood that the term "and / or" used in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0095] The word "if" as used herein may be interpreted as "at the time of" or "when" or "in response to determining" or "in response to detecting", depending on the context. Similarly, the phrases "if it is determined" or "if (stated condition or event) is detected" may be interpreted as "when it is determined" or "in response to determining" or "when detecting (stated condition or event)" or "in response to detecting (stated condition or event)", depending on the context.

[0096] The "first\second" mentioned in the embodiments is only to distinguish similar objects, and does not represent a specific order for the objects. It is understandable that the "first\second" can be interchanged with the specific order or sequence where permitted. It should be understood that the objects distinguished by "first\second" can be interchanged where appropriate, so that the embodiments described herein can be implemented in an order other than those illustrated or described herein.

[0097] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for controlling the negative pressure of a printer nozzle, applied to a printer using a stepper motor to drive an ink filling pump, characterized in that: include: According to the preset ink replenishing negative pressure threshold and the minimum ink replenishing negative pressure, the amount of ink required for the negative pressure of the pipeline cavity at the nozzle point to change from the ink replenishing negative pressure threshold to the minimum ink replenishing negative pressure is obtained, that is, the estimated required ink amount; Obtain the number of pixels of the printed image, and calculate the actual estimated inkjet volume based on the unit inkjet volume of each nozzle point and the number of pixels of the printed image; When the actual estimated inkjet printing amount reaches the estimated required ink amount, the actual estimated inkjet printing amount is converted into the number of steps required by the stepping motor, that is, the target number of steps, according to the unit stepping ink amount of the inkjet printer; The air pressure detection value of the air pressure sensor of the inkjet printer is obtained in real time, the target step number and the air pressure detection value are input into the PID control model, the actual step number of the stepper motor is output, and the operation of the stepper motor is controlled according to the actual step number to drive the ink replenishing pump to transport ink and reset the number of pixels of the printed image.

2. A method for controlling the negative pressure of a printer nozzle according to claim 1, characterized in that , define the maximum negative pressure of the printer as P max , the minimum negative pressure is P min , the ink filling negative pressure threshold is P m , the minimum negative pressure for ink filling is P j , then, |P max |>|P m |>|P j |>|P min |; wherein the ink replenishing negative pressure threshold is the negative pressure threshold at which the pump starts to replenish ink; and the minimum ink replenishing negative pressure is the actual minimum negative pressure of ink replenishing.

3. A method for controlling the negative pressure of a printer nozzle according to claim 2, characterized in that , the actual estimated coding volume V total The calculation formula is: In total =N×H dot ; Where N is the number of pixels of the printed image; V dot It is the unit inkjet volume of each nozzle point of the inkjet printer.

4. A method for controlling negative pressure of a printer nozzle according to claim 3, characterized in that: The target step number N steps The calculation formula is: N steps =V total ÷V step ; Among them, V step The unit stepping ink volume is the amount of ink pressed when the stepping motor takes one step.

5. A method for controlling negative pressure of a printer nozzle according to claim 4, characterized in that: The expression of the PID control model is as follows: N rsteps =N steps (K p ×P Deta +K i ×P Integ +K d ×P DDeta ); P Deta =P cur -P m ; P Integ =∑(P cur -P m ); P DDeta =P Deta -P PreDeta ; Among them, N rsteps is the actual number of steps; K p , K i , K d is the adjustment parameter of the PID control model; cur The negative pressure of the current air pressure detection value obtained; P Deta P cur With P m The error value of P Integ is the cumulative error value; P PreDeta is the error value of the last ink filling; P DDeta is the error change rate, that is, the current error value P Deta The error value P of the last time PreDeta difference.

6. A negative pressure control system for a printer nozzle, characterized in that: include: The required ink volume estimation module is used to obtain the ink volume required for the negative pressure of the pipeline cavity at the nozzle point to change from the ink replenishment negative pressure threshold to the minimum ink replenishment negative pressure according to the preset ink replenishment negative pressure threshold and the minimum ink replenishment negative pressure, that is, to estimate the required ink volume; The coding volume calculation module is used to obtain the number of pixels of the printed image and calculate the actual estimated coding volume based on the unit inkjet volume of each nozzle point and the number of pixels of the printed image; A target step number conversion module is used to convert the actual estimated inkjet amount into the step number required by the stepping motor, i.e., the target step number, according to the unit step ink amount of the inkjet printer when the actual estimated inkjet amount reaches the estimated required ink amount; The ink replenishment module is used to obtain the air pressure detection value of the air pressure sensor of the inkjet printer in real time, input the target step number and the air pressure detection value into the PID control model, output the actual step number of the stepper motor, and control the operation of the stepper motor according to the actual step number to drive the ink replenishment pump to transport ink and reset the number of pixels of the printed image.

7. A negative pressure control device for a printer nozzle, characterized in that: It comprises a processor and a memory, wherein the memory stores a computer program, and the computer program can be executed by the processor to implement a method for controlling the negative pressure of a printer nozzle as described in any one of claims 1 to 5.

8. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer-readable instructions, and when the computer-readable instructions are executed by a processor of a device where the computer-readable storage medium is located, a method for controlling the negative pressure of a printer nozzle is implemented as described in any one of claims 1 to 5.

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