Ink droplet calibration method of piezoelectric ink-jet printer and piezoelectric ink-jet printer

Abstract

The invention discloses an ink droplet calibration method of a piezoelectric ink-jet printer and the piezoelectric ink-jet printer, and the method comprises the steps: obtaining a first group of ink droplet volumes, the first group of ink droplet volumes being the ink droplet volumes obtained after ink-jet printing operation is executed through a first group of spray holes and a first driving waveform parameter in the piezoelectric ink-jet printer; and if the volume of the first group of ink droplets is greater than a target ink droplet volume, adjusting the first driving waveform parameter into a second driving waveform parameter so as to execute printing operation by using the second driving waveform parameter and the first group of spray holes until the volume of the first group of ink droplets is equal to the preset target ink droplet volume. According to the method, after the spray holes are grouped, the ink droplet volume corresponding to any spray hole group is calibrated; therefore, when the piezoelectric ink-jet printer carries out printing on a large-size display panel, the consistency of the volume of ink droplets is kept.

Description

Technical Field

[0001] The present application relates to the technical field of inkjet printing for display screens, and in particular to an ink droplet calibration method for a piezoelectric inkjet printer and a piezoelectric inkjet printer. Background Art

[0002] Currently, industrial printing equipment typically utilizes a multi-nozzle cascade approach to improve inkjet printing efficiency for large substrates. For example, a G6-sized display panel may utilize dozens or even hundreds of print heads, each with hundreds to thousands of nozzles.

[0003] In a piezoelectric inkjet printer, the internal driving unit is a PZT film. When driven by an external waveform, the PZT film generates strain; this strain squeezes the ink droplets within its channels, forcing them out. In actual production, especially for high-precision products like the printing of various functional layers in OLED displays, there is a high demand for consistent droplet volume across multiple nozzles.

[0004] However, the PZT film in the printhead undergoes multiple semiconductor manufacturing processes during its fabrication, which can lead to variations in the consistency of each nozzle. This can cause the PZT film to deform differently due to electrical stress, thus affecting the consistency of the ink droplet volume extruded from each nozzle.

[0005] Therefore, how to maintain the consistency of ink droplet volume during the piezoelectric inkjet printing process of large-size display panels has become a problem that needs to be solved. Summary of the Invention

[0006] The present application provides a piezoelectric inkjet printer ink droplet calibration method and a piezoelectric inkjet printer. The method groups the nozzles and then calibrates the ink droplet volume corresponding to any nozzle group; thereby allowing the piezoelectric inkjet printer to maintain consistency in ink droplet volume when printing on large-size display panels.

[0007] The first aspect of the present application discloses a droplet calibration method for a piezoelectric inkjet printer, the droplet calibration method comprising: obtaining a first group of droplet volumes, the first group of droplet volumes being the droplet volumes obtained after performing an inkjet printing operation in the piezoelectric inkjet printer using a first group of nozzles and a first drive waveform parameter; if the first group of droplet volumes is larger than a target droplet volume, adjusting the first drive waveform parameter to a second drive waveform parameter so as to perform a printing operation using the second drive waveform parameter and the first group of nozzles, until the first group of droplet volumes is equal to a preset target droplet volume.

[0008] In the above scheme, the driving waveform is fine-tuned for the ink droplets corresponding to any group of nozzles so that the volume of the ink droplets in this group is equal to the target ink droplet volume; and by setting the target ink droplet volume, the volume of the ink droplets ejected by all the nozzles in the piezoelectric inkjet print head is uniformly calibrated so that the volume of the ink droplets corresponding to any group of nozzles is consistent, thereby improving the consistency of the ink droplet volume.

[0009] In a possible embodiment, adjusting the first drive waveform parameters to the second drive waveform parameters specifically includes: adjusting the first amplitude of the first drive waveform to the second amplitude, wherein the first width is greater than the second amplitude, and the first drive waveform includes a trapezoidal wave, a pulse wave, and a square wave.

[0010] In the above scheme, there is no restriction on the waveform of the driving waveform, and it can also include a step waveform, that is, when rising to a high level or falling from a high level, it falls in multiple levels. Taking the trapezoidal wave as an example, the parameter adjustment of the driving waveform includes multiple parameters, such as: within the positive level period of the trapezoidal wave, the slope and duration of the rising edge, the value and duration of the high level, the slope and duration of the falling edge, and the duration when the voltage is 0; the same applies to the negative level period of the trapezoidal wave. However, in practice, it is found that the deformation of the PZT film is proportional to the amplitude of the waveform voltage of the input piezoelectric film, that is, the higher the pulse voltage, the greater its deformation, and the corresponding extruded ink droplet volume will be larger. Therefore, in the above example, directly adjusting the first amplitude to the second amplitude can reduce the volume of the ink droplets extruded by the nozzle, thereby reducing the volume of the first group of ink droplets. Direct amplitude adjustment is simpler and more convenient, and has better results.

[0011] In one possible embodiment, the piezoelectric inkjet printer includes multiple nozzles, and any one of the nozzles includes multiple nozzles. Before obtaining the first group of ink droplet volumes, the calibration method also includes: dividing the multiple nozzles into multiple groups, and numbering the multiple groups of nozzles to obtain multiple group numbers; in order of the group numbers, the multiple groups of nozzles sequentially perform inkjet printing operations with the first driving waveform parameters; obtaining the volumes of the multiple groups of ink droplets, one group of ink droplet volume corresponds to one group of nozzles; screening out ink droplet volume groups whose ink droplet volumes are not within the preset target ink droplet volume range; wherein the ink droplet volume group includes the ink droplet volume and the ink droplet volume group number; the ink droplet volume group includes the first group of ink droplet volumes, and the group number of the first group of ink droplet volumes is the same as the group number of the first group of nozzles.

[0012] The above scheme illustrates the ability to perform a preliminary screening of multiple nozzle orifice groups. For groups whose droplet volumes fall within a target droplet volume range, no individual droplet volume adjustment is required. Furthermore, the target droplet volume can be a relatively small numerical range or a single numerical value. When the target droplet volume is a numerical range, its numerical range should be smaller than the target droplet volume range in this example. In other words, the target droplet volume range in this example represents a coarse screening, while the target droplet volume in the above example represents a more refined droplet volume adjustment.

[0013] In one possible embodiment, obtaining the volumes of the multiple groups of ink droplets specifically includes: obtaining, by a visual camera, ink droplet images of each group of nozzles after the inkjet printing operation according to the order in which the multiple groups of nozzles perform the inkjet printing operation; obtaining the volume of each group of ink droplets based on the image of each group of ink droplets; and obtaining the volumes of the multiple groups of ink droplets, wherein the volume of one group of ink droplets corresponds to one group of nozzles, and the group number of each group of ink droplet volume is the same as the group number of the corresponding nozzles.

[0014] In the above example, a visual camera captures an image of each ink droplet group and determines the volume of each droplet group. This demonstrates that the droplet volume group number corresponds to the nozzle group number, facilitating synchronization of the parameters of nozzle groups and droplet volume groups across the entire piezoelectric printhead. Each drive waveform adjustment corresponds to a nozzle group. Only after this data is synchronized can accurate droplet volume feedback adjustment be performed. This avoids misalignment or parameter asynchrony between drive waveforms, nozzle groups, and droplet volume groups, which can lead to adjustment errors. Group numbering is simple, convenient, and efficient.

[0015] In one possible embodiment, the ink drop volume group includes a second group of ink drop volumes, and the group number of the second group of ink drop volumes is the same as the group number of the second group of nozzles; the ink drop calibration method also includes: after the first group of ink drop volumes is equal to the preset target ink drop volume, obtaining the second group of ink drop volumes in a preset order; wherein the preset order is the order of the group numbers, and the second group of ink drop volumes is the ink drop volume obtained after performing an inkjet printing operation with the second group of nozzles and the first drive waveform parameters in the piezoelectric inkjet printer; if the second group of ink drop volumes is larger than the target ink drop volume, the first drive waveform parameters are adjusted to third drive waveform parameters so as to perform a printing operation with the third drive waveform parameters and the second group of nozzles until the second group of ink drop volumes is equal to the preset target ink drop volume.

[0016] In the above scheme, it is intended to illustrate how to adjust the ink droplet volume when the ink droplet volumes corresponding to multiple nozzle groups are not within the target ink droplet volume range after the nozzles are grouped. The above example discloses that during the initial screening process, the piezoelectric nozzle can print all the nozzles according to the group number, and then screen out the groups whose ink droplet volumes are not within the target ink droplet volume range; when making precise ink droplet volume adjustments, it is done according to each nozzle group, and after completing the ink droplet volume calibration of one nozzle group, the ink droplet volume calibration of the next nozzle group is performed. The order of the nozzle groups is the order of the group numbers, which helps to make adjustments more accurate and refined. Each nozzle in the piezoelectric nozzle has its own number, and one nozzle group number corresponds to multiple nozzle numbers; the piezoelectric inkjet printer can control the inkjet of the nozzle corresponding to a nozzle group number based on these corresponding relationships.

[0017] In a possible implementation, the number of nozzles in any group of nozzles is determined by the number of ink droplets in an ink droplet image that can be captured by a visual camera at a single time, and the first driving waveform parameters are set by ink droplet characteristics and a printing frequency.

[0018] In the above scheme, the purpose is to disclose the basis for grouping. Generally speaking, the selection of a visual camera should take into account the application scenario, and the resolution of the image to be captured, the magnification of the lens, and the camera's field of view. However, since the scenario of this application is to use a piezoelectric nozzle to print on a large-scale substrate, the visual camera is often unable to capture the entire printed image at once; therefore, the maximum number of ink droplets in the ink droplet image that the visual camera can capture is used as the maximum number of nozzles in the nozzle grouping. In actual grouping, balancing calibration efficiency and calibration accuracy, an empirical value of the number can be tested.

[0019] In a possible implementation manner, the volume of the first group of ink droplets is an average volume of the first group of ink droplets.

[0020] In the above scheme, because a droplet volume group contains multiple droplets, using the average volume to represent the droplet volume of the droplet volume group is more accurate. It can be assumed that the differences in droplet volume within a droplet volume group are small and within the allowable error range; calibration can be performed using the target droplet volume range described above. Of course, calibration can also be performed directly using the target droplet volume in the above example.

[0021] In one possible embodiment, the step of printing the first group of ink droplets until the volume of the first group of ink droplets is equal to the preset target ink droplet volume specifically includes: if a printing operation is performed using the second drive waveform parameters and the first group of nozzles, and the volume of the first group of ink droplets is not equal to the target ink droplet volume, adjusting the second drive waveform parameters to fourth drive waveform parameters; and performing a printing operation using the fourth drive waveform parameters and the first group of nozzles until the volume of the first group of ink droplets is equal to the preset target ink droplet volume.

[0022] As can be seen from the above solutions, adjusting the amplitude (ie, voltage or level) of the driving waveform often requires multiple adjustments, thereby improving the accuracy of adjusting the volume of the ink droplets.

[0023] In one possible embodiment, the ink droplet calibration method includes: if the volume of the first group of ink droplets is smaller than the target ink droplet volume, adjusting the first drive waveform parameter to a fifth drive waveform parameter so as to perform a printing operation using the fifth drive waveform parameter and the first group of nozzles until the volume of the first group of ink droplets is equal to a preset target ink droplet volume.

[0024] In the above solution, it is intended to illustrate that if the ink droplet volume is smaller than the target ink droplet volume, the drive waveform parameters can also be adjusted, for example, by increasing the drive waveform amplitude as mentioned in the above solution.

[0025] A second aspect of the present application discloses a piezoelectric inkjet printer, comprising a processor, a memory, a user interface, and a network interface, wherein the memory is used to store instructions, the user interface and the network interface are both used to communicate with other devices, and the processor is used to execute the instructions stored in the memory so that the electronic device executes the following instructions:

[0026] Obtaining a first set of ink drop volumes, where the first set of ink drop volumes is the ink drop volume obtained after performing an inkjet printing operation in a piezoelectric inkjet printer using a first set of nozzles and first drive waveform parameters;

[0027] If the volume of the first group of ink droplets is greater than the target ink droplet volume, the first drive waveform parameters are adjusted to second drive waveform parameters so as to perform a printing operation using the second drive waveform parameters and the first group of nozzles until the volume of the first group of ink droplets is equal to the preset target ink droplet volume.

[0028] The beneficial effects of this application include:

[0029] Fine-tune the drive waveform for the ink droplets corresponding to any group of nozzles so that the volume of the ink droplets in that group equals the target droplet volume. By setting the target droplet volume, the volume of the ink droplets ejected by all nozzles in the piezoelectric inkjet print head is uniformly calibrated so that the volume of the ink droplets corresponding to any group of nozzles is consistent, thereby improving the consistency of the ink droplet volume.

[0030] There is no restriction on the waveform of the driving waveform, and it can also include a step waveform, that is, when it rises to a high level or drops from a high level, it drops in multiple levels. Taking the trapezoidal wave as an example, the parameter adjustment of the driving waveform includes a variety of parameters, such as: the slope and duration of the rising edge, the value and duration of the high level, the slope and duration of the falling edge, and the duration when the voltage is 0 within the positive level period of the trapezoidal wave; the same applies to the negative level period of the trapezoidal wave. However, in practice, it is found that the deformation of the PZT film is proportional to the amplitude of the waveform voltage of the input piezoelectric film, that is, the higher the pulse voltage, the greater its deformation, and the corresponding extruded ink droplet volume will be larger. Therefore, in the above example, directly adjusting the first amplitude to the second amplitude can reduce the volume of the ink droplets extruded by the nozzle, thereby reducing the volume of the first group of ink droplets. Direct amplitude adjustment is simpler and more convenient, and the effect is better;

[0031] Multiple nozzle groups can be preliminarily screened, and for groups whose droplet volumes fall within the target droplet volume range, no individual droplet volume adjustment is required. Furthermore, the target droplet volume can be a relatively small numerical range or a single numerical value. When the target droplet volume is a numerical range, its numerical range must be smaller than the target droplet volume range in this example. In other words, the target droplet volume range in this example is a coarse screening, while the target droplet volume in the above example represents a more refined droplet volume adjustment.

[0032] Each group of ink droplets is captured by a visual camera, and the volume of each group of ink droplets is obtained. This is to illustrate that the group number of the ink droplet volume corresponds to the group number of the nozzle, so that the parameters of the nozzle group and the ink droplet volume group in the entire piezoelectric nozzle can be synchronized. One drive waveform adjustment must correspond to one nozzle group. Only after these data are synchronized can accurate ink droplet volume feedback adjustment be performed. This avoids mismatches in drive waveforms, nozzle groups, and ink droplet volume groups, or missynchronization of parameters, which can lead to adjustment errors. The correspondence between number groups is simple, convenient, and efficient.

[0033] This section describes how to adjust the ink droplet volume when there are multiple nozzle groups whose corresponding ink droplet volumes are not within the target ink droplet volume range after the nozzles are grouped. The above example discloses that during the initial screening process, the piezoelectric nozzle can print all the nozzles according to the group number, and then screen out the groups whose ink droplet volumes are not within the target ink droplet volume range; when making precise adjustments to the ink droplet volume, it is done one nozzle group at a time, and after completing the ink droplet volume calibration for one nozzle group, the ink droplet volume calibration for the next nozzle group is performed. The order of the nozzle groups is the order of the group numbers, which helps to make adjustments more accurate and refined. Each nozzle in the piezoelectric nozzle has its own number, and one nozzle group number corresponds to multiple nozzle numbers; the piezoelectric inkjet printer can control the inkjet of the nozzle corresponding to a nozzle group number based on these corresponding relationships;

[0034] Generally speaking, the selection of a visual camera should take into account the application scenario, taking into account the resolution of the image to be captured, the magnification of the lens, and the camera's field of view. However, since the scenario of this application is to use a piezoelectric nozzle to print on a large-scale substrate, the visual camera is often unable to capture the entire printed image at once; therefore, the maximum number of ink droplets in the ink droplet image that the visual camera can capture is used as the maximum number of nozzles in the nozzle grouping. In actual grouping, balancing calibration efficiency and calibration accuracy, an empirical value of the number can be tested;

[0035] Because a droplet volume group contains multiple droplets, it's more accurate to use the average volume to represent the droplet volume of the droplet volume group. It can be assumed that the differences in droplet volume within a droplet volume group are small and within the allowable error range. Calibration can be performed using the target droplet volume range described above. Alternatively, calibration can be performed directly using the target droplet volume in the example above. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 A schematic diagram of a piezoelectric film structure disclosed in this application specification;

[0037] Figure 2 This is a flow chart of an ink drop calibration method for a piezoelectric inkjet printer disclosed in this application specification;

[0038] Figure 3 A schematic flow chart of a nozzle grouping method disclosed in this application specification;

[0039] Figure 4 This is a flow chart of a method for obtaining the volumes of multiple groups of ink droplets disclosed in this application specification;

[0040] Figure 5 This is a flow chart of another method for calibrating ink droplet volume disclosed in this application specification;

[0041] Figure 6 This is a schematic structural diagram of a piezoelectric inkjet printer disclosed in this application specification.

[0042] In the above figure: ink 10, ceramic substrate 20, vibration diaphragm 30, piezoelectric ceramic 40 in working state, ink chamber 50, piezoelectric ceramic 60, electrode 70, driving power supply 80, nozzle panel 90. DETAILED DESCRIPTION

[0043] In order to enable those skilled in the art to better understand the technical solutions in this specification, the technical solutions in the embodiments of this specification will be clearly and completely described below in conjunction with the drawings in the embodiments of this specification. Obviously, the described embodiments are only part of the embodiments of this application, not all of the embodiments.

[0044] In the description of the embodiments of this application, words such as "for example" or "for instance" are used to indicate examples, illustrations, or explanations. Any embodiment or design described as "for example" or "for instance" in the embodiments of this application should not be construed as being preferred or advantageous over other embodiments or designs. Rather, the use of words such as "for example" or "for instance" is intended to present the relevant concepts in a concrete manner.

[0045] In the description of the embodiments of the present application, the term "multiple" means two or more. For example, multiple systems refer to two or more systems, and multiple screen terminals refer to two or more screen terminals. In addition, the terms "first" and "second" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the indicated technical features. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. The terms "including", "comprising", "having" and their variations all mean "including but not limited to", unless otherwise specifically emphasized.

[0046] The ink drop calibration method disclosed in this specification is applicable to the following scenarios. Figure 1 As shown, the ink 10 in the ink chamber 50 applies an electric field to the electrode 70 under the action of the driving power supply 80, and the piezoelectric ceramic 40 in the working state bends to squeeze the ink out of the nozzle hole of the nozzle panel 90.

[0047] Furthermore, for array printheads, ink droplet formation within the printhead is achieved by pushing PZT thin films on or near the sides of individual chambers. The electrodes of the PZT thin films are connected to metal contacts on the chip's surface via metal traces within the chip. Various bonding methods can be used to connect these contact signals to the gold fingers of an external FPC cable. The electrical signals generated by the driver board to drive the PZTs must be connected to the FPC cable via a high-density connector. To adjust each nozzle, this drive signal must be mapped to the nozzle number in the order of the bonding. If each nozzle is driven by a single drive signal, a corresponding digital-to-analog conversion and amplification circuit is required to ensure accurate adjustment of each nozzle. This creates a problem: the circuit board cannot be scaled up indefinitely. Furthermore, during FPC cable production, the gold finger pad spacing is limited, otherwise it cannot be properly processed. This means that with a large number of printheads, it is impossible to individually adjust the droplet volume for each nozzle.

[0048] Therefore, the present specification describes an engineering feasible method. The grouping adjustment driving can be performed according to the order of the nozzles, the parameters such as the amplitude, the frequency and the duty cycle of a group of nozzles remain consistent, and a multiplexing switch chip is added in front of the PZT film of each nozzle. If a single nozzle in a group of nozzles deviates too much, the corresponding nozzle can be closed by software shielding. In this way, the parameters such as the amplitude, the frequency and the duty cycle of the nozzles are independently adjustable, and the engineering actual realizability is also taken into account; the volume of the driving circuit can be compressed to facilitate installation and reduce the corresponding cost, and the FPC cable can also be normally produced.

[0049] The details are described below.

[0050] The present specification discloses a method for calibrating ink drops of a piezoelectric inkjet printer. As Figure 2 The method for calibrating ink drops includes steps S101-S102.

[0051] S101, obtaining a first group of ink drop volumes, the first group of ink drop volumes being obtained after performing inkjet printing operation with a first group of nozzles and a first driving waveform parameter in a piezoelectric inkjet printer.

[0052] S102, if the first group of ink drop volumes is greater than a target ink drop volume, adjusting the first driving waveform parameter to a second driving waveform parameter, so as to perform printing operation with the second driving waveform parameter and the first group of nozzles until the first group of ink drop volumes is equal to a preset target ink drop volume.

[0053] In the above example, the driving waveform of the ink drops corresponding to any group of nozzles is fine-tuned, so that the volume of the ink drops of the group is equal to the target ink drop volume; the volume of the ink drops corresponding to any group of nozzles is consistent, thereby improving the consistency of the ink drop volume of the entire piezoelectric nozzle.

[0054] In one example, the first driving waveform parameter is adjusted to the second driving waveform parameter, specifically including: adjusting a first amplitude of the first driving waveform to a second amplitude, wherein the first amplitude is greater than the second amplitude, and the first driving waveform includes a trapezoidal wave, a pulse wave and a square wave.

[0055] In the above example, there is no restriction on the waveform of the driving waveform, and it can also include a step waveform, that is, when rising to a high level or falling from a high level, it falls in multiple levels. Taking the trapezoidal wave as an example, the parameter adjustment of the driving waveform includes multiple parameters, such as: within the positive level period of the trapezoidal wave, the slope and duration of the rising edge, the value and duration of the high level, the slope and duration of the falling edge, and the duration when the voltage is 0; the same applies to the negative level period of the trapezoidal wave. However, in practice, it is found that the deformation of the PZT film is proportional to the amplitude of the waveform voltage of the input piezoelectric film, that is, the higher the pulse voltage, the greater its deformation, and the corresponding extruded ink droplet volume will be larger. Therefore, in the above example, directly adjusting the first amplitude to the second amplitude can reduce the volume of the ink droplets extruded by the nozzle, thereby reducing the volume of the first group of ink droplets. Direct amplitude adjustment is simpler and more convenient, and has better results.

[0056] In one example, if Figure 3 The piezoelectric inkjet printer includes a plurality of nozzles, any one of which includes a plurality of nozzle holes. Before obtaining the volume of the first set of ink droplets, the calibration method further includes steps S301-S304.

[0057] S301: Divide the plurality of nozzle holes into a plurality of groups, and number the plurality of groups of nozzle holes to obtain a plurality of group numbers.

[0058] S302 , in the order of the group numbers, the plurality of groups of nozzles sequentially perform inkjet printing operations using the first driving waveform parameters.

[0059] S303: Obtain volumes of multiple groups of ink droplets, where the volume of one group of ink droplets corresponds to one group of nozzles.

[0060] S304. Filter out ink droplet volume groups whose ink droplet volumes are not within a preset target ink droplet volume range; wherein the ink droplet volume group includes an ink droplet volume and an ink droplet volume group number; the ink droplet volume group includes the first group of ink droplet volumes, and the group number of the first group of ink droplet volumes is the same as the group number of the first group of nozzles.

[0061] The above examples are intended to illustrate that a preliminary screening can be performed on multiple nozzle groups. For groups whose ink droplet volumes are within the target ink droplet volume range, it is not necessary to adjust the ink droplet volume of each group individually.

[0062] In addition, the above-mentioned target ink droplet volume can be a relatively small numerical range, or it can be directly a numerical value; when the above-mentioned target ink droplet volume is a numerical range, its numerical range is smaller than the target ink droplet volume range in this example; in other words, the target ink droplet volume range in this example is a coarse screen, and the target ink droplet volume in the above example is a more fine ink droplet volume adjustment.

[0063] In one example, the volume of multiple groups of ink droplets is obtained, such as Figure 4 The method includes steps S401-S403.

[0064] S401 , according to the order in which the plurality of nozzle groups perform inkjet printing operations, sequentially acquire ink droplet images after each group of nozzles performs the inkjet printing operation through a visual camera.

[0065] S402 : Obtain the volume of each group of ink droplets according to each group of ink droplet images.

[0066] S403: Acquire volumes of multiple groups of ink droplets, where one group of ink droplet volumes corresponds to one group of nozzles, and the group number of each group of ink droplet volumes is the same as the group number corresponding to the nozzles.

[0067] In the above example, a visual camera captures an image of each ink droplet group and determines the volume of each droplet group. This demonstrates that the droplet volume group number corresponds to the nozzle group number, facilitating synchronization of the parameters of nozzle groups and droplet volume groups across the entire piezoelectric printhead. Each drive waveform adjustment corresponds to a nozzle group. Only after this data is synchronized can accurate droplet volume feedback adjustment be performed. This avoids misalignment or parameter asynchrony between drive waveforms, nozzle groups, and droplet volume groups, which can lead to adjustment errors. Group numbering is simple, convenient, and efficient.

[0068] In one example, the ink drop volume group includes a second group of ink drop volumes, and the group number of the second group of ink drop volumes is the same as the group number of the second group of nozzles; the ink drop calibration method further includes steps S501-S502, such as Figure 5 shown.

[0069] S501. After the volume of the first group of ink droplets is equal to the preset target ink droplet volume, obtain the volume of the second group of ink droplets in a preset order; wherein the preset order is the order of group numbers, and the volume of the second group of ink droplets is the volume of ink droplets obtained after performing an inkjet printing operation in a piezoelectric inkjet printer using a second group of nozzles and first drive waveform parameters.

[0070] S502. If the volume of the second group of ink droplets is greater than the target ink droplet volume, the first drive waveform parameters are adjusted to third drive waveform parameters so as to perform a printing operation using the third drive waveform parameters and the second group of nozzles until the volume of the second group of ink droplets is equal to the preset target ink droplet volume.

[0071] The above example discloses that during the initial screening process, the piezoelectric nozzle can print all the nozzles according to the group number, and then screen out the groups whose ink droplet volume is not within the target ink droplet volume range; when performing precise ink droplet volume adjustment, it is performed according to each nozzle group. After completing the ink droplet volume calibration of one nozzle group, the ink droplet volume calibration of the next nozzle group is performed. The order of the nozzle groups is the order of the group numbers, which helps to make adjustments more accurate and refined. Each nozzle in the piezoelectric nozzle has its own number, and one nozzle group number corresponds to multiple nozzle numbers; the piezoelectric inkjet printer can control the inkjet of the nozzle corresponding to a nozzle group number based on these corresponding relationships.

[0072] In one example, the number of nozzles in any group of nozzles is determined by the number of ink droplets in an ink droplet image that can be captured by a visual camera at a single time, and the first driving waveform parameters are set by ink droplet characteristics and a printing frequency.

[0073] Generally speaking, the selection of a visual camera depends on the application scenario, taking into account the resolution of the image to be captured, the lens magnification, and the camera's field of view. However, since this application involves printing on large substrates using a piezoelectric printhead, a visual camera often cannot capture the entire printed image in one go. Therefore, the maximum number of ink droplets in the ink droplet image captured by the visual camera is used as the maximum number of nozzles in the nozzle group.

[0074] In actual grouping, the calibration efficiency and accuracy are balanced, and an empirical value of the quantity can be obtained through testing.

[0075] In one example, the volume of the first group of ink drops is an average volume of the first group of ink drops.

[0076] In the above example, because a droplet volume group contains multiple droplets, using the average volume to represent the droplet volume of the droplet volume group is more accurate. It can be assumed that the differences in droplet volume within a droplet volume group are small and within the allowable error range; calibration can be performed using the target droplet volume range described above. Alternatively, calibration can be performed directly using the target droplet volume in the above example.

[0077] This specification does not provide detailed explanations on the calculation of the average volume of ink droplets. Those skilled in the art will appreciate that it can be obtained by methods such as weighing, volumetric or optical methods.

[0078] In one example, the step of printing the first group of ink droplets until the volume of the first group of ink droplets is equal to the preset target ink droplet volume specifically includes: if a printing operation is performed using the second drive waveform parameters and the first group of nozzles, and the volume of the first group of ink droplets is not equal to the target ink droplet volume, adjusting the second drive waveform parameters to fourth drive waveform parameters; and performing a printing operation using the fourth drive waveform parameters and the first group of nozzles until the volume of the first group of ink droplets is equal to the preset target ink droplet volume.

[0079] At this time, adjusting the amplitude (ie, voltage or level) of the driving waveform often requires multiple adjustments, thereby improving the accuracy of adjusting the volume of the ink droplet.

[0080] In one example, the ink drop calibration method includes: if the volume of the first group of ink droplets is smaller than the target ink droplet volume, adjusting the first drive waveform parameter to a fifth drive waveform parameter so as to perform a printing operation using the fifth drive waveform parameter and the first group of nozzles until the volume of the first group of ink droplets is equal to a preset target ink droplet volume.

[0081] At this time, if the ink droplet volume is smaller than the target ink droplet volume, the drive waveform parameters may be adjusted, for example, by increasing the drive waveform amplitude as mentioned in the above solution.

[0082] It should be noted that if the ink droplet volume is equal to the target ink droplet volume, there is no need to adjust the drive waveform parameters. This situation will be screened out in the above-mentioned initial screening process. In addition, in the same group of nozzles in this manual, the volume of ink droplets ejected by the nozzles is within the allowable error range; if in the same nozzle group, there are one or more ink droplets whose volume is significantly different from the target ink droplet volume, the nozzle numbers corresponding to these ink droplets can be obtained, and these nozzle numbers can be disabled (i.e., printing is not allowed). In this way, it can be ensured that the corresponding ink droplet volumes of the nozzles in a nozzle group are within the allowable error range.

[0083] This specification also discloses a piezoelectric inkjet printer, comprising a processor, a memory, a user interface, and a network interface. The memory is used to store instructions. The user interface and the network interface are both used to communicate with other devices. The processor is used to execute the instructions stored in the memory so that the electronic device executes the following instructions:

[0084] Obtaining a first set of ink drop volumes, where the first set of ink drop volumes is the ink drop volume obtained after performing an inkjet printing operation in a piezoelectric inkjet printer using a first set of nozzles and first drive waveform parameters;

[0085] If the volume of the first group of ink droplets is greater than the target ink droplet volume, the first drive waveform parameters are adjusted to second drive waveform parameters so as to perform a printing operation using the second drive waveform parameters and the first group of nozzles until the volume of the first group of ink droplets is equal to the preset target ink droplet volume.

[0086] In one example, adjusting the first drive waveform parameters to the second drive waveform parameters specifically includes: adjusting the first amplitude of the first drive waveform to the second amplitude, wherein the first width is greater than the second amplitude, and the first drive waveform includes a trapezoidal wave, a pulse wave, and a square wave.

[0087] In one example, the piezoelectric inkjet printer includes multiple nozzles, and any one of the nozzles includes multiple nozzles. Before obtaining the first group of ink droplet volumes, the calibration method also includes: dividing the multiple nozzles into multiple groups, and numbering the multiple groups of nozzles to obtain multiple group numbers; in order of the group numbers, the multiple groups of nozzles sequentially perform inkjet printing operations with the first driving waveform parameters; obtaining the volumes of multiple groups of ink droplets, one group of ink droplet volumes corresponds to one group of nozzles; screening out ink droplet volume groups whose ink droplet volumes are not within a preset target ink droplet volume range; wherein the ink droplet volume group includes ink droplet volume and ink droplet volume group number; the ink droplet volume group includes the first group of ink droplet volumes, and the group number of the first group of ink droplet volumes is the same as the group number of the first group of nozzles.

[0088] In one example, obtaining the volumes of the multiple groups of ink droplets specifically includes: obtaining, by a visual camera, ink droplet images of each group of nozzles after the inkjet printing operation according to the order in which the multiple groups of nozzles perform the inkjet printing operation; obtaining the volume of each group of ink droplets based on each group of ink droplet images; and obtaining the volumes of the multiple groups of ink droplets, wherein the volume of one group of ink droplets corresponds to a group of nozzles, and the group number of each group of ink droplet volume is the same as the group number of the corresponding nozzles.

[0089] In one example, the ink drop volume group includes a second group of ink drop volumes, and the group number of the second group of ink drop volumes is the same as the group number of the second group of nozzles; the ink drop calibration method also includes: after the first group of ink drop volumes is equal to the preset target ink drop volume, obtaining the second group of ink drop volumes in a preset order; wherein the preset order is the order of the group numbers, and the second group of ink drop volumes is the ink drop volume obtained after performing an inkjet printing operation with the second group of nozzles and the first drive waveform parameters in the piezoelectric inkjet printer; if the second group of ink drop volumes is larger than the target ink drop volume, the first drive waveform parameters are adjusted to third drive waveform parameters so as to perform a printing operation with the third drive waveform parameters and the second group of nozzles until the second group of ink drop volumes is equal to the preset target ink drop volume.

[0090] In one example, the number of nozzles in any group of nozzles is determined by the number of ink droplets in an ink droplet image that can be captured by a visual camera at a single time, and the first driving waveform parameters are set by ink droplet characteristics and a printing frequency.

[0091] In one example, the volume of the first group of ink drops is an average volume of the first group of ink drops.

[0092] In one example, the step of printing the first group of ink droplets until the volume of the first group of ink droplets is equal to the preset target ink droplet volume specifically includes: if a printing operation is performed using the second drive waveform parameters and the first group of nozzles, and the volume of the first group of ink droplets is not equal to the target ink droplet volume, adjusting the second drive waveform parameters to fourth drive waveform parameters; and performing a printing operation using the fourth drive waveform parameters and the first group of nozzles until the volume of the first group of ink droplets is equal to the preset target ink droplet volume.

[0093] In one example, the ink drop calibration method includes: if the volume of the first group of ink droplets is smaller than the target ink droplet volume, adjusting the first drive waveform parameter to a fifth drive waveform parameter so as to perform a printing operation using the fifth drive waveform parameter and the first group of nozzles until the volume of the first group of ink droplets is equal to a preset target ink droplet volume.

[0094] It should be noted that the above embodiments provide devices that implement their functions using only the division of the above functional modules as examples. In actual applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above. In addition, the device and method embodiments provided in the above embodiments are based on the same concept. The specific implementation process is detailed in the method embodiment and will not be repeated here.

[0095] The specification also discloses a computer-readable storage medium, which stores instructions. When the instructions are executed, the above method is executed.

[0096] This embodiment also discloses an electronic device, which may be a piezoelectric inkjet printer, to perform the above method. Figure 6 The electronic device may include: at least one processor 601 , at least one communication bus 602 , a display 603 , a network interface 604 , and at least one memory 605 .

[0097] The communication bus 602 is used to implement the connection and communication between these components.

[0098] The display 603 may include a display screen (Display) and a camera (Camera).

[0099] The network interface 604 may optionally include a standard wired interface or a wireless interface (such as a WI-FI interface).

[0100] The processor 601 may include one or more processing cores. The processor 601 utilizes various interfaces and circuits to connect various components within the server. It executes instructions, programs, code sets, or instruction sets stored in the memory 605, as well as accesses data stored in the memory 605, to perform various server functions and process data. Optionally, the processor 601 may be implemented using at least one hardware form factor selected from the group consisting of a digital signal processing (DSP), a field-programmable gate array (FPGA), and a programmable logic array (PLA). The processor 601 may integrate one or a combination of a central processing unit (CPU), a graphics processing unit (GPU), and a modem. The CPU primarily processes the operating system, user interface, and application programs; the GPU is responsible for rendering and drawing the content displayed on the display screen; and the modem handles wireless communications. It is understood that the modem may not be integrated into the processor 601 and may be implemented as a separate chip.

[0101] Among them, the memory 605 may include a random access memory 605 (Random Access Memory, RAM), and may also include a read-only memory 605 (Read-Only Memory). Optionally, the memory 605 includes a non-transitory computer-readable storage medium. The memory 605 can be used to store instructions, programs, codes, code sets or instruction sets. The memory 605 may include a program storage area and a data storage area, wherein the program storage area may store instructions for implementing an operating system, instructions for at least one function (such as a touch function, a sound playback function, an image playback function, etc.), instructions for implementing the above-mentioned various method embodiments, etc.; the data storage area may store data involved in the above-mentioned various method embodiments, etc. The memory 605 may also be at least one storage device located away from the aforementioned processor 601. As shown in the figure, the memory 605 as a computer storage medium may include an operating system, a network communication module, and application programs of a display module.

[0102] exist Figure 6In the electronic device shown, the display 603 is mainly used to provide an interface for the user to input, and obtain data input by the user; and the processor 601 can be used to call an application stored in the storage 605, and when executed by the one or more processors 601, cause the electronic device to perform the method of one or more of the above-described embodiments.

[0103] It should be noted that, for the foregoing method embodiments, in order to simply describe, they are all described as a series of action combinations, but those skilled in the art should know that the present application is not limited to the order of the actions described, because according to the present application, some steps can be performed in other order or at the same time. Secondly, those skilled in the art should know that the embodiments described in the specification all belong to preferred embodiments, and the actions and modules involved are not necessarily required by the present application.

[0104] In the above embodiments, the description of each embodiment has its own focus, and the parts not described in detail in a certain embodiment can be referred to the related description of other embodiments.

[0105] In several embodiments provided by the present application, it should be understood that the disclosed device can be implemented in other ways. For example, the device embodiments described above are only schematic. The division of the units is only a logical function division. There can be another division manner for actual implementation, for example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the displayed or discussed mutual couplings or direct couplings or communication connections between different parts can be indirect couplings or communication connections through some interfaces, devices or units, and can be electrical or other forms.

[0106] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they can be located in one place, or can be distributed on a plurality of network units. Part or all of the units can be selected according to actual needs to achieve the purpose of the embodiment scheme.

[0107] In addition, each functional unit in each embodiment of the present application can be integrated in one processing unit, or each unit can exist physically, or two or more units can be integrated in one unit. The integrated unit can be realized in the form of hardware, or in the form of software functional unit.

[0108] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable memory 605. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product. The computer software product is stored in a memory 605 and includes several instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the various embodiments of the present application. The aforementioned memory 605 includes various media that can store program code, such as a USB flash drive, a mobile hard drive, a magnetic disk, or an optical disk.

[0109] The above are merely exemplary embodiments of the present disclosure and are not intended to limit the scope of the present disclosure. That is, any equivalent changes and modifications made in accordance with the teachings of the present disclosure are still within the scope of the present disclosure. After considering the disclosure of the specification and the truth of practice, those skilled in the art will easily think of other embodiments of the present disclosure. This application is intended to cover any variations, uses or adaptations of the present disclosure, which follow the general principles of the present disclosure and include common knowledge or customary technical means in the art that are not recorded in the present disclosure. The description and examples are to be regarded as exemplary only, and the scope and spirit of the present disclosure are defined by the claims.

Claims

1. A method for calibrating ink droplets of a piezoelectric inkjet printer, characterized in that: The ink drop calibration method comprises: Obtaining a first set of ink drop volumes, where the first set of ink drop volumes is the ink drop volume obtained after performing an inkjet printing operation in a piezoelectric inkjet printer using a first set of nozzles and first drive waveform parameters; If the volume of the first group of ink droplets is greater than the target ink droplet volume, the first driving waveform parameters are adjusted to second driving waveform parameters so as to perform a printing operation using the second driving waveform parameters and the first group of nozzles until the volume of the first group of ink droplets is equal to the preset target ink droplet volume.

2. The ink drop calibration method according to claim 1, characterized in that: The adjusting the first driving waveform parameter to the second driving waveform parameter specifically includes: The first amplitude of the first driving waveform is adjusted to a second amplitude, wherein the first amplitude is greater than the second amplitude, and the first driving waveform includes a trapezoidal wave, a pulse wave, and a square wave.

3. The ink drop calibration method according to claim 1, characterized in that: The piezoelectric inkjet printer includes a plurality of nozzles, any one of which includes a plurality of nozzle holes. Before obtaining the volume of the first set of ink droplets, the calibration method further includes: Dividing the plurality of nozzle holes into a plurality of groups, and numbering the plurality of groups of nozzle holes to obtain a plurality of group numbers; In the order of the group numbers, the plurality of groups of nozzles sequentially perform inkjet printing operations using the first driving waveform parameters; Obtaining the volumes of multiple groups of ink droplets, where the volume of one group of ink droplets corresponds to one group of nozzles; Filter out ink drop volume groups whose ink drop volumes are not within a preset target ink drop volume range; wherein the ink drop volume group includes an ink drop volume and an ink drop volume group number; the ink drop volume group includes the first group of ink drop volumes, and the group number of the first group of ink drop volumes is the same as the group number of the first group of nozzles.

4. The ink drop calibration method according to claim 3, characterized in that: The obtaining of volumes of the plurality of groups of ink droplets specifically includes: According to the order in which the plurality of nozzles perform the inkjet printing operation, sequentially acquiring, by a visual camera, an ink droplet image of each nozzle group after the nozzle group performs the inkjet printing operation; According to each group of ink droplet images, the volume of each group of ink droplets is obtained; The volumes of multiple groups of ink droplets are obtained, where each group of ink droplet volumes corresponds to a group of nozzle holes, and the group number of each group of ink droplet volumes is the same as the group number corresponding to the nozzle holes.

5. The ink drop calibration method according to claim 3, characterized in that: The ink drop volume group includes a second group of ink drop volumes, wherein the group number of the second group of ink drop volumes is the same as the group number of the second group of nozzles; The ink drop calibration method further includes: After the volume of the first group of ink droplets equals a preset target ink droplet volume, obtaining a second group of ink droplet volumes in a preset order; wherein the preset order is the order of group numbers, and the second group of ink droplet volumes are ink droplet volumes obtained after performing an inkjet printing operation in the piezoelectric inkjet printer using the second group of nozzles and the first drive waveform parameters; If the volume of the second group of ink droplets is greater than the target ink droplet volume, the first drive waveform parameters are adjusted to third drive waveform parameters so as to perform a printing operation using the third drive waveform parameters and the second group of nozzles until the volume of the second group of ink droplets is equal to the preset target ink droplet volume.

6. The ink drop calibration method according to any one of claims 1 to 5, characterized in that: The number of nozzles in any group of nozzles is determined by the number of ink droplets in an ink droplet image that can be captured by a visual camera at a single time, and the first driving waveform parameters are set by ink droplet characteristics and printing frequency.

7. The ink drop calibration method according to any one of claims 1 to 5, characterized in that: The volume of the first group of ink drops is an average volume of the first group of ink drops.

8. The ink drop calibration method according to any one of claims 1 to 5, characterized in that: The method of waiting until the volume of the first group of ink droplets is equal to a preset target ink droplet volume specifically includes: If a printing operation is performed using the second driving waveform parameters and the first group of nozzles, and the volume of the first group of ink droplets is not equal to the target ink droplet volume, adjusting the second driving waveform parameters to fourth driving waveform parameters; A printing operation is performed using the fourth driving waveform parameters and the first group of nozzles until a volume of the first group of ink droplets is equal to a preset target ink droplet volume.

9. The ink drop calibration method according to claim 1, characterized in that: The ink drop calibration method comprises: If the volume of the first group of ink droplets is smaller than the target ink droplet volume, the first driving waveform parameter is adjusted to a fifth driving waveform parameter so as to perform a printing operation using the fifth driving waveform parameter and the first group of nozzles until the volume of the first group of ink droplets is equal to the preset target ink droplet volume.

10. A piezoelectric inkjet printer, characterized in that: The electronic device includes a processor, a memory, a user interface, and a network interface, wherein the memory is used to store instructions, the user interface and the network interface are both used to communicate with other devices, and the processor is used to execute the instructions stored in the memory so that the electronic device executes the following instructions: Obtaining a first set of ink drop volumes, where the first set of ink drop volumes is the ink drop volume obtained after performing an inkjet printing operation in a piezoelectric inkjet printer using a first set of nozzles and first drive waveform parameters; If the volume of the first group of ink droplets is greater than the target ink droplet volume, the first drive waveform parameters are adjusted to second drive waveform parameters so as to perform a printing operation using the second drive waveform parameters and the first group of nozzles until the volume of the first group of ink droplets is equal to the preset target ink droplet volume.

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