Spraying method and spraying system

Abstract

A spraying method and a spraying system are disclosed. The spraying method includes the following operations. A first ink drop is driven by a first voltage signal. A first signal feature of the first voltage signal is adjusted according to a first standard deviation of a speed of the first ink drop after being driven. A first signal feature value of the first signal feature is determined when the first standard deviation is less than a preset standard deviation. A model is generated according to at least the first signal feature value and a first ink drop feature value of the first ink drop. A second voltage signal is generated according to the model and a second ink drop feature value of a second ink drop. The second ink drop is driven by the second voltage signal. In this way, trial and error of the second voltage signal is not required, and time and cost consumed are reduced.

Description

Technical Field

[0001] This invention relates to a spraying technology, and more particularly to a spraying method and spraying system. Background Technology

[0002] When dyeing fabrics, the quality of the coating is related to the speed of the ink droplets. To obtain a suitable droplet speed, users need to make adjustments through trial and error. However, performing multiple trials for each type of ink droplet would be extremely time-consuming and labor-intensive. Therefore, developing technologies that can overcome these problems is an important task in this field. Summary of the Invention

[0003] This disclosure includes a spraying method. The spraying method includes the following operations: Driving a first ink droplet using a first voltage signal; Adjusting a first signal characteristic of the first voltage signal based on a first standard deviation of the velocity of the first ink droplet after it is driven; Determining a first signal characteristic value of the first signal characteristic when the first standard deviation is less than a preset standard deviation; Generating a model based at least on the first signal characteristic value and a first ink droplet characteristic value; Generating a second voltage signal based on the model and a second ink droplet characteristic value; Driving a second ink droplet using the second voltage signal.

[0004] In some embodiments, the first ink droplet characteristic value includes a first viscosity value and a first surface tension value of the first ink droplet.

[0005] In some embodiments, the first signal features include a first frequency of the first voltage signal, a first driving voltage level of the first voltage signal, a first duration of the first voltage signal having the first driving voltage level, a first rising slope of the first voltage signal rising to the first driving voltage level, and a first falling slope of the first voltage signal falling from the first driving voltage level.

[0006] In some embodiments, the model includes a function representing a second signal characteristic of the second voltage signal, the function including a first power term and a second power term of the second ink droplet characteristic value.

[0007] In some embodiments, the spraying method further includes the following operations: Driving a third ink droplet, different from the first ink droplet, using a third voltage signal; adjusting a third signal characteristic of the third voltage signal based on a third standard deviation of the velocity of the third ink droplet after it is driven; determining a third signal characteristic value when the third standard deviation is less than a preset standard deviation; and correcting the model based on the third signal characteristic value and the third ink droplet characteristic value.

[0008] In some embodiments, adjusting the first signal characteristic of the first voltage signal includes the following operations: When the first viscosity value of the first ink droplet is greater than a preset viscosity value, at least one of the following operations is performed: Increasing the first frequency of the first voltage signal; Increasing the first driving voltage level of the first voltage signal; Increasing the first duration of the first voltage signal having the first driving voltage level; Increasing the absolute value of the first rise slope of the first voltage signal to the first driving voltage level; Increasing the absolute value of the first fall slope of the first voltage signal falling from the first driving voltage level. When the first surface tension value of the first ink droplet is greater than a preset surface tension value, at least one of the following operations is performed: Decreasing the first frequency of the first voltage signal; Increasing the first driving voltage level of the first voltage signal; Increasing the first duration of the first voltage signal having the first driving voltage level; Increasing the absolute value of the first rise slope of the first voltage signal to the first driving voltage level; Increasing the absolute value of the first fall slope of the first voltage signal falling from the first driving voltage level.

[0009] This disclosure includes a spraying system. The spraying system includes a nozzle, a control device, a memory, and a processor. The nozzle is used to spray a first ink droplet according to a first voltage signal and to spray a second ink droplet according to a second voltage signal. The control device is used to adjust a first signal characteristic of the first voltage signal until the standard deviation of the velocity of the first ink droplet is less than a preset standard deviation. The memory is used to store a first signal characteristic value of the first signal characteristic when the standard deviation is less than the preset standard deviation. The processor is used to build a model based on the first signal characteristic value and the first ink droplet characteristic value, and to generate a second signal characteristic value of the second voltage signal based on the model and the second ink droplet characteristic value.

[0010] In some embodiments, the first ink droplet characteristic value includes a first viscosity value and a first surface tension value of the first ink droplet, and the second ink droplet characteristic value includes a second viscosity value and a second surface tension value of the second ink droplet.

[0011] In some embodiments, the first signal features include a first frequency of the first voltage signal, a first driving voltage level of the first voltage signal, a first duration of the first voltage signal having the first driving voltage level, a first rising slope of the first voltage signal rising to the first driving voltage level, and a first falling slope of the first voltage signal falling from the first driving voltage level; and the second signal features include a second frequency of the second voltage signal, a second driving voltage level of the second voltage signal, a second duration of the second voltage signal having the second driving voltage level, a second rising slope of the second voltage signal rising to the second driving voltage level, and a second falling slope of the second voltage signal falling from the second driving voltage level.

[0012] In some embodiments, the model includes a function representing a second signal characteristic of the second voltage signal. The function includes first-order and second-order terms of the second ink droplet characteristic value. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of a spraying system according to an embodiment of the present invention;

[0014] Figure 2 The waveform timing diagram of the first voltage signal and the second voltage signal is shown according to an embodiment of the present invention;

[0015] Figure 3 This is a diagram illustrating the relationship between ink droplet characteristic values ​​and signal characteristics according to an embodiment of the present invention;

[0016] Figure 4 This is a flowchart illustrating a spraying method according to an embodiment of the present invention.

[0017] [Symbol Explanation]

[0018] 100: Spraying System

[0019] 110: Control device

[0020] 120: Processor

[0021] 130: Memory

[0022] 140: Sprayer Head

[0023] 150: Mobile device

[0024] VS1: First voltage signal

[0025] VS2: Second voltage signal

[0026] D1: The First Drop of Ink

[0027] D2: Second ink drop

[0028] FB: Substrate

[0029] 200: Waveform Timing Diagram

[0030] P21~P26: Period

[0031] VLL, VMM: Voltage Levels

[0032] VDD1: First driving voltage level

[0033] VDD2: Second driving voltage level

[0034] 300: Relationship Diagram

[0035] DP1~DP10: Data points

[0036] 310: Model

[0037] 400: Spraying Method

[0038] OP41~OP48: Operation Detailed Implementation

[0039] In this document, when an element is referred to as a “connection” or “coupled,” it may mean an “electrical connection” or “electrical coupling.” “Connection” or “coupled” can also be used to indicate the operation or interaction between two or more elements. Furthermore, although terms such as “first,” “second,” etc., are used herein to describe different elements, these terms are merely used to distinguish elements or operations described using the same technical terminology. Unless the context clearly indicates otherwise, these terms do not specifically refer to or imply any order or sequence, nor are they intended to limit the invention.

[0040] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It will be further understood that terms such as those defined in commonly used dictionaries should be interpreted as having meanings consistent with their meanings in the context of the relevant technology and this invention, and will not be interpreted as having idealized or overly formal meanings unless expressly defined herein.

[0041] The terminology used herein is for the purpose of describing particular embodiments only and is not restrictive. As used herein, unless the content clearly indicates otherwise, the singular forms “a,” “an,” and “the” are intended to include the plural forms, including “at least one.” “Or” means “and / or.” As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed items. It should also be understood that, when used in this specification, the terms “comprising” and / or “including” specify the presence of the stated features, areas, integrals, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, areas, integrals, steps, operations, elements, components, and / or combinations thereof.

[0042] The following describes several embodiments of this disclosure with reference to the accompanying drawings. For clarity, many practical details will be described in the following description. However, it should be understood that these practical details should not be used to limit the scope of this disclosure. That is, these practical details are not essential in some embodiments of this disclosure. Furthermore, for the sake of simplicity, some conventional structures and elements will be shown in the drawings in a simplified schematic manner.

[0043] Figure 1This is a schematic diagram of a spraying system 100 according to an embodiment of the present invention. In some embodiments, the spraying system 100 includes a control device 110, a processor 120, a memory 130, a spray nozzle 140, and a moving device 150. Figure 1 As shown, the control device 110 is coupled to the processor 120, memory 130, nozzle 140 and moving device 150, and the processor 120 and memory 130 are coupled to each other.

[0044] like Figure 1 As shown, the control device 110 is used to generate a first voltage signal VS1 and a second voltage signal VS2. In some embodiments, the printhead 140 is used to drive a first ink droplet D1 according to the first voltage signal VS1 and to drive a second ink droplet D2 according to the second voltage signal VS2, so that the first ink droplet D1 and the second ink droplet D2 fall from the printhead 140 onto the substrate FB on the moving device 150. In some embodiments, the moving device 150 is used to move the substrate FB.

[0045] In some embodiments, the spraying system 100 further includes a photosensitive device (not shown). The photosensitive device is used to capture an image of the first ink droplet D1 to calculate a first standard deviation of the velocity of the first ink droplet D1.

[0046] In some embodiments, the control device 110 adjusts a first signal characteristic of the first voltage signal VS1 until a first standard deviation is less than a preset standard deviation. In some embodiments, the preset standard deviation is approximately 0.035 m / s.

[0047] In some embodiments, memory 130 is used to store a first signal feature value of a first signal feature when the first standard deviation is less than a preset standard deviation. Details of the first signal feature are described below. Figure 2 Further examples are provided in the embodiments.

[0048] In some embodiments, the processor 120 is used to establish a model based on the first signal feature value and the first ink droplet feature value of the first ink droplet D1, for example... Figure 3 The model 310 shown is used to generate the second signal characteristic value of the second voltage signal VS2 based on the model and the second ink droplet characteristic value of the second ink droplet D2. Details of the model are as follows... Figure 3 Further examples are provided in the embodiments.

[0049] In some embodiments, the first ink droplet characteristic value includes a first viscosity value and a first surface tension value of the first ink droplet D1, and the second ink droplet characteristic value includes a second viscosity value and a second surface tension value of the second ink droplet D2.

[0050] Figure 2The waveform timing diagram 200 illustrates a first voltage signal VS1 and a second voltage signal VS2 according to an embodiment of the present invention. Figure 2 As shown, the horizontal axis of waveform timing diagram 200 represents time, and the vertical axis represents voltage. Waveform timing diagram 200 contains sequentially arranged periods P21 to P26.

[0051] During period P21, the first voltage signal VS1 rises from voltage level VLL to first drive voltage level VDD1 with a first rising slope.

[0052] During period P22, the first voltage signal VS1 is maintained at the first drive voltage level VDD1. In some embodiments, the duration of period P22 corresponds to the first duration of the first voltage signal VS1 having the first drive voltage level VDD1.

[0053] During period P23, the first voltage signal VS1 drops from the first drive voltage level VDD1 to the voltage level VLL with a first falling slope.

[0054] During periods P24 and P26, the first voltage signal VS1 has a voltage level VLL. During period P25, the first voltage signal VS1 has a voltage level VMM.

[0055] In some embodiments, the duration of periods P21 to P26 corresponds to one cycle of the first voltage signal VS1. In some embodiments, after period P26, the first voltage signal VS1 has multiple waveforms similar to those shown in periods P21 to P26. In some embodiments, the first frequency of the first voltage signal VS1 is inversely proportional to the period of the first voltage signal VS1.

[0056] In some embodiments, the second voltage signal VS2 has a waveform similar to that of the first voltage signal VS1. Therefore, the second voltage signal VS2 is also illustrated by waveform timing diagram 200.

[0057] During period P21, the second voltage signal VS2 rises from voltage level VLL to second drive voltage level VDD2 with a second rising slope.

[0058] During period P22, the second voltage signal VS2 is maintained at the second drive voltage level VDD2. In some embodiments, the duration of period P22 corresponds to a second duration of the second voltage signal VS2 having the second drive voltage level VDD2.

[0059] During period P23, the second voltage signal VS2 drops from the second drive voltage level VDD2 to the voltage level VLL with a second falling slope.

[0060] During periods P24 and P26, the second voltage signal VS2 has a voltage level VLL. During period P25, the second voltage signal VS2 has a voltage level VMM.

[0061] In some embodiments, the duration of periods P21 to P26 corresponds to one cycle of the second voltage signal VS2. In some embodiments, after period P26, the second voltage signal VS2 has multiple waveforms similar to those shown in periods P21 to P26. In some embodiments, the second frequency of the second voltage signal VS2 is inversely proportional to the period of the second voltage signal VS2.

[0062] In some embodiments, the first signal features of the first voltage signal VS1 include a first frequency of the first voltage signal VS1, a first driving voltage level VDD1 of the first voltage signal VS1, a first duration of the first voltage signal VS1 having the first driving voltage level VDD1, a first rising slope of the first voltage signal VS1 rising to the first driving voltage level VDD1, and a first falling slope VS1 of the first voltage signal falling from the first driving voltage level VDD1.

[0063] In some embodiments, the second signal features of the second voltage signal VS2 include a second frequency of the second voltage signal VS2, a second driving voltage level VDD2 of the second voltage signal VS2, a second duration of the second voltage signal VS2 having the second driving voltage level VDD2, a second rising slope of the second voltage signal VS2 rising to the second driving voltage level VDD2, and a second falling slope VS2 of the second voltage signal falling from the second driving voltage level VDD2.

[0064] Figure 3 Graph 300 illustrates the relationship between ink droplet characteristic values ​​and signal characteristics according to an embodiment of the present invention. Figure 3 As shown, the relationship diagram 300 includes an X-axis, a Y-axis, and a Z-axis. The X-axis and Y-axis correspond to two characteristic values ​​of the ink droplet, such as the surface tension value and viscosity value of the ink droplet. The Z-axis corresponds to the signal characteristics of the voltage signal driving the ink droplet, such as the first signal characteristic of the first voltage signal VS1 mentioned above.

[0065] like Figure 3 As shown, the relationship diagram 300 also includes data points DP1 to DP10. In some embodiments, each of data points DP1 to DP10 corresponds to an ink droplet and a voltage signal driving the ink droplet. For example, data point DP1 corresponds to a first viscosity value and a first surface tension value of a first ink droplet D1, and a first signal characteristic value of a first voltage signal VS1 driving the first ink droplet D1. In some embodiments, the standard deviation of the droplet velocity corresponding to each of data points DP1 to DP10 is less than a preset standard deviation.

[0066] like Figure 3 As shown, the relationship diagram 300 also includes model 310. In some embodiments, Figure 1 The processor 120 shown is used to generate model 310 based on some or all of the data points DP1 to DP10. For example, the processor 120 is used to generate a function F(X1,Y1) representing model 310 by performing regression analysis based on the data points DP1 to DP10, where X1 and Y1 represent two droplet characteristic values, and the function F(X1,Y1) represents the signal characteristics of the voltage signals corresponding to X1 and Y1. In some embodiments, the function F(X1,Y1) includes first-order and second-order terms of the droplet characteristic values. For example, F(X1,Y1) = C1 × X1 2 +C2×C2 2 +C3×X1×X2+C4×X1+C5×X2+C6, where C1~C6 are coefficients generated through regression analysis.

[0067] Figure 4 This is a flowchart illustrating a spraying method 400 according to an embodiment of the present invention. Please refer to... Figure 4 Spraying method 400 includes operations OP41 to OP48.

[0068] When operating OP41, the first ink droplet D1 is driven by the first voltage signal VS1.

[0069] In operation OP42, analyze the velocity of the first ink droplet D1, for example, calculate the first standard deviation of the velocity of the first ink droplet D1 after it is driven.

[0070] In operation OP43, determine whether the first standard deviation is less than the preset standard deviation. If the first standard deviation is less than the preset standard deviation, proceed to operation OP45. If the first standard deviation of the velocity of the first ink droplet D1 is greater than or equal to the preset standard deviation, proceed to operation OP44.

[0071] During operation OP44, the first signal characteristic of the first voltage signal VS1 is adjusted according to the first standard deviation. After operation OP44, operations OP42 to OP43 are repeated until the first standard deviation is less than the preset standard deviation.

[0072] In operation OP45, the first signal characteristic value is determined, for example, the first signal characteristic value is stored in... Figure 1 The memory cell 130 shown.

[0073] In operation OP46, a model is generated based at least on the first signal characteristic value and the first ink droplet characteristic value of the first ink droplet D1, for example... Figure 3 Model 310 is shown.

[0074] During operation OP47, a second voltage signal VS2 is generated based on the model and the second droplet characteristic value of the second droplet D2. For example, the second droplet characteristic value is substituted into the function F(X1,X2) to generate the corresponding second signal characteristic value, and the second voltage signal VS2 is generated based on the second signal characteristic value.

[0075] When operating OP48, the second ink droplet D2 is driven by the second voltage signal VS2, so that the second standard deviation of the speed of the second ink droplet D2 is less than the preset standard deviation.

[0076] In some practices, to reduce the standard deviation of ink droplet speed, users adjust the signal characteristics of the voltage signal driving the ink droplets through trial and error. This requires a significant amount of time and manpower.

[0077] Compared to the above approach, in this embodiment of the invention, a model can be generated based on the first voltage signal VS1 by operating OP41 to OP46, and then the second voltage signal VS2 can be directly generated by operating OP47. In this way, the second ink droplet D2 with a speed conforming to the preset standard deviation can be obtained without trial and error on the second signal characteristics of the second voltage signal VS2, saving a lot of time and manpower.

[0078] In some embodiments, the spraying method 400 further includes the following operations: Driving a third ink droplet, different from the first ink droplet D1, using a third voltage signal; adjusting a third signal characteristic of the third voltage signal based on a third standard deviation of the velocity of the third ink droplet after it is driven; determining a third signal characteristic value when the third standard deviation is less than a preset standard deviation; and correcting the model based on the third signal characteristic value and the third ink droplet characteristic value, for example... Figure 3 Model 310 is shown. In some embodiments, the third ink droplet, the third ink droplet characteristic value, the third voltage signal, and the third signal characteristic value correspond to... Figure 3 The data point DP2 is shown.

[0079] In some embodiments, operation OP44 includes the following operations. When the first viscosity value of the first ink droplet D1 is greater than a preset viscosity value, at least one of the following operations is performed: increasing the first frequency of the first voltage signal VS1; increasing the first driving voltage level VDD1 of the first voltage signal VS1; increasing the first duration of the first voltage signal VS1 having the first driving voltage level VDD1; increasing the absolute value of the first rising slope of the first voltage signal VS1 rising to the first driving voltage level VDD1; or increasing the absolute value of the first falling slope of the first voltage signal VS1 falling from the first driving voltage level VDD1. In some embodiments, the preset viscosity value is approximately 12 cP.

[0080] In some embodiments, operation OP44 further includes the following operations. When the first surface tension value of the first ink droplet D1 is greater than a preset surface tension value, at least one of the following operations is performed: reducing the first frequency of the first voltage signal VS1; reducing the first frequency of the first voltage signal VS1; increasing the first driving voltage level VDD1 of the first voltage signal VS1; increasing the first duration of the first voltage signal VS1 having the first driving voltage level VDD1; increasing the absolute value of the first rising slope of the first voltage signal VS1 rising to the first driving voltage level VDD1; or increasing the absolute value of the first falling slope of the first voltage signal VS1 falling from the first driving voltage level VDD1. In some embodiments, the preset surface tension value is approximately 38.5 dyn / cm.

[0081] In summary, the method 400 performed by the spraying system 100 can generate a model based on the first voltage signal VS1, and then generate a second voltage signal VS2 based on the model, without needing to perform trial and error on the second signal characteristics of the second voltage signal VS2. Compared with traditional methods, this disclosure can reduce the time and cost of trial and error on the second signal characteristics, and directly generate a second voltage signal VS2 that makes the velocity of the second ink droplet D2 conform to a preset standard deviation.

[0082] Although the present invention has been disclosed above by way of embodiments, it is not intended to limit the present invention. Anyone skilled in the art can make some modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the scope defined in the appended claims.

Claims

1. A spraying method, characterized in that, include: The first ink droplet is driven by the first voltage signal; Based on the first standard deviation of the velocity of the first ink droplet after it is driven, adjust the first signal characteristic of the first voltage signal; When the first standard deviation is less than the preset standard deviation, the first signal feature value is determined; A model is generated based at least on the first signal feature value and the first ink droplet feature value; Based on the model and the characteristic value of the second ink droplet, a second voltage signal is generated; as well as The second voltage signal drives the second ink droplet. The first signal feature that adjusts the first voltage signal includes: When the first viscosity value of the first ink droplet is greater than the preset viscosity value, at least one of the following operations shall be performed: Increase the first frequency of the first voltage signal; Increase the first driving voltage level of the first voltage signal; Increase the first duration of the first voltage signal having the first driving voltage level; Increase the absolute value of the first rise slope of the first voltage signal to the first driving voltage level; or Increase the absolute value of the first descent slope of the first voltage signal from the first driving voltage level; and When the first surface tension value of the first ink droplet is greater than the preset surface tension value, at least one of the following operations shall be performed: Reduce the first frequency of the first voltage signal; Increase the first driving voltage level of the first voltage signal; Increase the first duration of the first voltage signal having the first driving voltage level; Increase the absolute value of the first rise slope of the first voltage signal to the first driving voltage level; or Increase the absolute value of the first descent slope of the first voltage signal from the first driving voltage level.

2. The spraying method as described in claim 1, characterized in that, The first ink droplet characteristic value includes the first viscosity value and the first surface tension value of the first ink droplet.

3. The spraying method as described in claim 1, characterized in that, The first signal features include the first frequency of the first voltage signal, the first driving voltage level of the first voltage signal, the first duration of the first voltage signal having the first driving voltage level, the first rising slope of the first voltage signal rising to the first driving voltage level, and the first falling slope of the first voltage signal falling from the first driving voltage level.

4. The spraying method as described in claim 1, characterized in that, The model includes functions representing second signal characteristics of the second voltage signal. The function includes a first-order term and a second-order term of the second ink droplet characteristic value.

5. The spraying method as described in claim 1, characterized in that, Also includes: A third ink droplet, different from the first ink droplet, is driven by a third voltage signal; The third signal characteristic of the third voltage signal is adjusted based on the third standard deviation of the velocity of the third ink droplet after it is driven. When the third standard deviation is less than the preset standard deviation, the third signal feature value of the third signal feature is determined; as well as The model is corrected based on the third signal feature value and the third ink droplet feature value.

6. A spraying system, characterized in that, include: The printhead is used to eject a first ink droplet according to a first voltage signal and to eject a second ink droplet according to a second voltage signal; The control device is used to adjust the first signal characteristic of the first voltage signal until the standard deviation of the velocity of the first ink droplet is less than a preset standard deviation; A memory, used to store the first signal feature value of the first signal feature when the standard deviation is less than the preset standard deviation; as well as The processor is configured to establish a model based on the first signal feature value and the first ink droplet feature value, and to generate a second signal feature value of the second voltage signal based on the model and the second ink droplet feature value. When the first viscosity value of the first ink droplet is greater than the preset viscosity value, the processor performs at least one of the following operations: Increase the first frequency of the first voltage signal; Increase the first driving voltage level of the first voltage signal; Increase the first duration of the first voltage signal having the first driving voltage level; Increase the absolute value of the first rise slope of the first voltage signal to the first driving voltage level; or Increase the absolute value of the first descent slope of the first voltage signal from the first driving voltage level and When the first surface tension value of the first ink droplet is greater than the preset surface tension value, at least one of the following operations shall be performed: Reduce the first frequency of the first voltage signal; Increase the first driving voltage level of the first voltage signal; Increase the first duration of the first voltage signal having the first driving voltage level; Increase the absolute value of the first rise slope of the first voltage signal to the first driving voltage level; or Increase the absolute value of the first descent slope of the first voltage signal from the first driving voltage level.

7. The spraying system as described in claim 6, characterized in that, The first ink droplet characteristic value includes the first viscosity value and the first surface tension value of the first ink droplet, and The second ink droplet characteristic value includes the second viscosity value and the second surface tension value of the second ink droplet.

8. The spraying system as described in claim 7, characterized in that, The first signal features include the first frequency of the first voltage signal, the first driving voltage level of the first voltage signal, the first duration of the first voltage signal having the first driving voltage level, the first rising slope of the first voltage signal rising to the first driving voltage level, and the first falling slope of the first voltage signal falling from the first driving voltage level. The second signal features include a second frequency of the second voltage signal, a second driving voltage level of the second voltage signal, a second duration of the second voltage signal having the second driving voltage level, a second rising slope of the second voltage signal rising to the second driving voltage level, and a second falling slope of the second voltage signal falling from the second driving voltage level.

9. The spraying system as claimed in claim 8, characterized in that, The model includes functions representing the second signal characteristics of the second voltage signal. The function includes a first-order term and a second-order term of the second ink droplet characteristic value.

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