Ink-jet printer nozzle control system and control method based on temperature and humidity compensation

Abstract

The invention relates to an ink-jet printer nozzle control system and control method based on temperature and humidity compensation. The control system comprises a temperature and humidity acquisition unit, a control unit and a piezoelectric driving unit. The temperature and humidity acquisition unit adopts a high-precision digital temperature sensor and a high-precision digital humidity sensor, and the high-precision digital temperature sensor and the high-precision digital humidity sensor are arranged near a spray head, communicate with the control unit through an IIC interface and are used for acquiring the environment temperature T and the relative humidity H in real time; hardware of the control unit is realized based on an embedded processor, and the control unit is used for completing temperature and humidity data acquisition, driving waveform calculation based on a temperature and humidity compensation algorithm and driving waveform output. And the piezoelectric driving unit is used for controlling the voltage change of the printer nozzle through the driving waveform output by the control unit, outputting trapezoidal waves with adjustable amplitude and duty ratio, and driving the nozzle to jet ink droplets. According to the invention, the problems of ink flying, satellite dripping or drop point deviation caused by temperature change are avoided; and the printing definition in a ship cabin under a humid working condition is ensured.

Description

Technical Field

[0001] This invention relates to the field of printing technology, and in particular to a printhead control system and control method for an inkjet printer based on temperature and humidity compensation. Background Technology

[0002] Piezoelectric inkjet printers are widely used output devices. Their working principle relies on a printhead made of piezoelectric ceramics that deforms under voltage, compressing its internal cavity and ejecting ink onto a medium to form an image. In practical applications, changes in ambient temperature and humidity significantly impact print quality. Specifically, fluctuations in temperature and humidity cause changes in ink viscosity, which in turn affect the flight speed, droplet distribution, and landing accuracy of the ink droplets ejected from the piezoelectric printhead. While environmental conditions are relatively stable in a typical office environment, they are far more complex and variable in a marine environment due to the unique nature of ship operations. For example, during sea voyages, the interior of a ship may experience significant temperature and humidity fluctuations, especially during changes in sea area or season. Therefore, the print quality of inkjet printers used in marine environments is greatly affected by the environment.

[0003] In a shipboard environment, due to the confined space and the characteristics of equipment operation, temperature and humidity changes can be more drastic and unpredictable. When the ambient temperature rises, the ink viscosity decreases, which may cause the ink droplets to fly faster, potentially leading to satellite droplets or trailing phenomena, thus affecting the accuracy of their landing position. Conversely, when the temperature is too low, the ink viscosity increases, which may result in insufficient kinetic energy for ink droplet ejection, leading to blurred images or color deviations. At the same time, changes in humidity also have a significant impact on ink performance: in high humidity environments, the rate of water evaporation in the ink slows down, which may cause ink droplets to deform during flight; while in low humidity environments, the ink dries quickly, which may cause printhead clogging or uneven droplet distribution.

[0004] In existing technologies, inkjet printers typically use a fixed voltage to drive piezoelectric ceramics or rely on optical sensors to provide feedback on ink droplet position for closed-loop adjustment. However, these methods do not consider the direct impact of ambient temperature and humidity on the physical properties of ink, resulting in insufficient printing stability under varying temperature and humidity conditions. Therefore, there is an urgent need to develop a novel temperature and humidity compensation technology that can monitor and dynamically adjust the printer's operating parameters in real time to adapt to changes in environmental conditions, thereby ensuring stable image quality even in complex environments. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention proposes a printhead control method for inkjet printers based on temperature and humidity compensation.

[0006] One of the above-mentioned objectives of the present invention is achieved by the following technical solution: A printhead control system for an inkjet printer based on temperature and humidity compensation, characterized in that it includes a temperature and humidity acquisition unit, a control unit, and a piezoelectric drive unit; The temperature and humidity acquisition unit uses a high-precision digital temperature sensor and a high-precision digital humidity sensor. The high-precision digital temperature sensor and the high-precision digital humidity sensor are arranged near the nozzle and communicate with the control unit through the IIC interface. The high-precision digital temperature sensor and the high-precision digital humidity sensor are used to acquire the ambient temperature T and relative humidity H in real time. The hardware of the control unit is implemented based on an embedded processor. The control unit is used to complete temperature and humidity data acquisition, drive waveform calculation based on temperature and humidity compensation algorithm, and drive waveform output. The piezoelectric drive unit is used to control the voltage change of the printer head through the drive waveform output by the control unit, and output a trapezoidal wave with adjustable amplitude and duty cycle to drive the print head to eject ink droplets.

[0007] Furthermore, the control unit includes a temperature and humidity data acquisition module, a drive waveform calculation module, and a drive waveform output module; wherein, the temperature and humidity data acquisition module communicates with a high-precision digital temperature sensor and a high-precision digital humidity sensor through an IIC interface to acquire temperature and humidity data near the nozzle. The drive waveform calculation module includes a voltage compensation module and a pulse width compensation module. The voltage compensation module dynamically adjusts the voltage amplitude of the drive waveform based on the collected temperature information according to the drive voltage-temperature compensation model formula. The pulse width compensation module dynamically adjusts the pulse width of the drive waveform based on the collected humidity information according to the pulse width-humidity compensation model formula. The drive waveform calculation function module supports a parameter calibration interface, which can input ink temperature and humidity compensation coefficients A, B, C and reference values ​​U0, t0, H0 through a host computer; where A is the temperature compensation coefficient, B is the ink characteristic constant, and C is the humidity compensation coefficient. The drive waveform output function module communicates with the piezoelectric drive unit and outputs the drive waveform generated by the drive waveform calculation function module to the piezoelectric drive unit.

[0008] The second objective of this invention is achieved through the following technical solution: A printhead control method for an inkjet printer based on temperature and humidity compensation, employing the aforementioned printhead control system for an inkjet printer based on temperature and humidity compensation, includes the following steps: Step 1: Establish the drive voltage-temperature compensation model and pulse width-humidity compensation model through the drive waveform calculation function module of the control unit; Step 2: By calibrating the driving voltage and driving waveform for optimal printing effect under different temperatures and humidity, the driving voltage-temperature and pulse width-humidity are fitted into curves that conform to the formula, and the ink temperature and humidity compensation coefficients A, B, and C are obtained. Step 3: Input the ink temperature and humidity compensation coefficients (A, B, C) and reference values ​​(U0, t0, H0) into the control unit via the host computer. During the printing process, the drive voltage and pulse width can be calculated in real time based on the temperature and humidity data fed back by the temperature and humidity acquisition unit, and a drive waveform can be generated. The piezoelectric drive unit drives the piezoelectric printhead to eject ink droplets according to the set drive waveform.

[0009] Furthermore, in step 1: the adjustment of the driving voltage and temperature compensation voltage is based on the following formula:

[0010] Where A1 and B are ink characteristic constants, T is absolute temperature (K), U0 is reference voltage, and η0 is reference viscosity; From the above two formulas, the following driving voltage-temperature compensation model formula can be derived:

[0011] Where A is the temperature compensation coefficient, and its value is... B is the ink characteristic constant; The formula for the pulse width-humidity compensation model is as follows:

[0012] Where C is the humidity compensation coefficient, H is the relative humidity, H0 is the reference relative humidity, and t0 is the reference pulse width.

[0013] Furthermore, the calibration process in step 2 is as follows: Step 2.1: Using room temperature of 25℃ and relative humidity of 40% as the reference temperature T0 and reference humidity H0, adjust the driving voltage and pulse width under this environment, print a standard graphic, select the best printing effect, and record the driving voltage at this time as the reference voltage U0 and the pulse width as the reference width t0. Step 2.2: At a relative humidity of 40% and temperatures (T) of 15℃, 35℃, 45℃, and 55℃, adjust the driving voltage, print standard graphics, select the best printing effect, and record the driving voltage U at each time. Step 2.3: Substitute the driving voltage U and temperature data T into the driving voltage-temperature compensation model formula, fit it into the driving voltage-temperature (UT) compensation curve, and calculate the ink temperature compensation coefficients A and B; Step 2.4: At a temperature of 25℃ and relative humidity of 40%, 50%, 60%, 70%, 80%, and 90%, respectively, adjust the pulse width, print standard graphics, select the best printing effect, and record the pulse width Δt at each time. Step 2.5: Substitute the pulse width Δt and relative humidity data H into the pulse width-humidity compensation model formula, fit it into a pulse width-humidity (Δt-H) compensation curve, and calculate the ink humidity compensation coefficient C; Step 2.6: Input the ink temperature and humidity compensation coefficients A, B, C and the reference values ​​U0, t0, H0 into the control unit so that the piezoelectric printhead ejects ink droplets according to the corrected U and Δt; under multiple temperature and humidity conditions, the compensation coefficients are fine-tuned according to the printing effect to obtain the best printing effect, thus obtaining the final temperature and humidity compensation coefficients. Step 2.7: When using different types of ink or printing paper, repeat steps 2.1 to 2.6 to obtain the corresponding ink temperature and humidity compensation coefficients A, B, C and reference values ​​U0, t0, H0, forming a compensation coefficient database for different types of ink and printing paper for the printer, which is then stored in the control unit to achieve automatic temperature and humidity compensation for various types of ink or printing paper.

[0014] The advantages and positive effects of this invention are as follows: This invention significantly improves printing stability and accuracy in variable temperature and humidity environments, such as those on ships, by monitoring ambient temperature and humidity in real time and dynamically adjusting the drive parameters of the piezoelectric inkjet printer. Through a drive voltage-temperature compensation algorithm, the drive power supply is dynamically adjusted to keep droplet velocity fluctuations within ±3%, avoiding ink splatter, satellite droplets, or droplet misalignment caused by temperature changes. The introduction of pulse width-humidity compensation reduces droplet tailing by 70% in high humidity environments, ensuring print clarity in humid conditions inside ship cabins. This method is highly versatile, adapting to different inks, such as water-based, UV, and solvent-based inks, through a parameter calibration interface, and can be extended to fields such as industrial coding and 3D printing. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the composition of the inkjet printer printhead control system based on temperature and humidity compensation according to the present invention. Figure 2 This is a flowchart of the calibration method of the present invention; Figure 3 This is a flowchart of the printing process of the present invention. Detailed Implementation

[0016] The structure of the present invention will be further described below with reference to the accompanying drawings and embodiments. It should be noted that these embodiments are descriptive and not limiting.

[0017] For an inkjet printer printhead control system based on temperature and humidity compensation, please refer to [link / reference]. Figures 1-3 Its invention features three main components: a temperature and humidity acquisition unit, a control unit, and a piezoelectric drive unit.

[0018] The temperature and humidity acquisition unit uses a high-precision digital temperature sensor, which is placed near the nozzle to avoid airflow interference and communicates with the control unit through the IIC interface. The high-precision digital temperature sensor is used to collect the ambient temperature T (unit: K) and relative humidity H (unit: %RH) in real time.

[0019] The control unit's hardware is implemented based on an embedded processor and includes a temperature and humidity data acquisition module, a drive waveform calculation module, and a drive waveform output module. These modules are used to acquire temperature and humidity data, calculate drive waveforms based on temperature and humidity compensation algorithms, and output drive waveforms. The temperature and humidity data acquisition module communicates with high-precision digital temperature and humidity sensors via an IIC interface to acquire temperature and humidity data near the nozzle.

[0020] The drive waveform calculation module includes a voltage compensation module and a pulse width compensation module. The voltage compensation module dynamically adjusts the voltage amplitude of the drive waveform based on the acquired temperature information, according to the drive voltage-temperature compensation model formula. The pulse width compensation module dynamically adjusts the pulse width of the drive waveform based on the acquired humidity information, according to the pulse width-humidity compensation model formula.

[0021] The drive waveform calculation module supports a parameter calibration interface, allowing input of ink temperature and humidity compensation coefficients A, B, and C, and reference values ​​U0, t0, and H0 via a host computer. Here, A is the temperature compensation coefficient, B is the ink characteristic constant, and C is the humidity compensation coefficient.

[0022] The drive waveform output function module communicates with the piezoelectric drive unit and outputs the drive waveform generated by the drive waveform calculation function module to the piezoelectric drive unit.

[0023] The piezoelectric drive unit is used to control the voltage change of the printer head through the drive waveform output by the control unit, and output a trapezoidal wave with adjustable amplitude and duty cycle to drive the print head to eject ink droplets.

[0024] A printhead control method for an inkjet printer based on temperature and humidity compensation, employing the aforementioned printhead control system for an inkjet printer based on temperature and humidity compensation, includes the following steps: Step 1: Establish the drive voltage-temperature compensation model and the pulse width-humidity compensation model through the drive waveform calculation function module of the control unit.

[0025] The driving voltage-temperature compensation system calculates the current ink viscosity η based on the Andreid equation and dynamically adjusts the piezoelectric driving voltage U to maintain a stable droplet flight speed. The driving voltage-temperature compensation voltage adjustment is based on the following formula:

[0026] Where A1 and B are ink characteristic constants, T is absolute temperature (K), U0 is reference voltage, and η0 is reference viscosity.

[0027] From the above two formulas, the following driving voltage-temperature compensation model formula can be derived:

[0028] Where A is the temperature compensation coefficient, and its value is... B is the ink characteristic constant.

[0029] Pulse width-humidity compensation refers to adjusting the driving pulse width Δt in high humidity environments to compensate for the impact of ink evaporation delay on droplet formation. The pulse width-humidity compensation model formula is as follows:

[0030] Where C is the humidity compensation coefficient, H is the relative humidity, H0 is the reference relative humidity, and t0 is the reference pulse width.

[0031] Step 2: By calibrating the driving voltage and driving waveform for optimal printing effect under different temperatures and humidity, the driving voltage-temperature and pulse width-humidity are fitted into curves that conform to the formula, and the ink temperature and humidity compensation coefficients A, B, and C are obtained.

[0032] Specific calibration steps: Step 2.1: Using room temperature of 25℃ and relative humidity of 40% as the reference temperature T0 and reference humidity H0, adjust the driving voltage and pulse width under this environment, print a standard graphic, select the best printing effect, and record the driving voltage at this time as the reference voltage U0 and the pulse width as the reference width t0.

[0033] Step 2.2: At a relative humidity of 40% and temperatures (T) of 15℃, 35℃, 45℃, and 55℃, adjust the driving voltage, print standard graphics, select the best printing effect, and record the driving voltage U at each time.

[0034] Step 2.3: Substitute the driving voltage U and temperature data T into the driving voltage-temperature compensation model formula, fit it into the driving voltage-temperature (UT) compensation curve, and calculate the ink temperature compensation coefficients A and B.

[0035] Step 2.4: At a temperature of 25℃ and relative humidity of 40%, 50%, 60%, 70%, 80%, and 90%, respectively, adjust the pulse width, print standard graphics, select the best printing effect, and record the pulse width Δt at each time.

[0036] Step 2.5: Substitute the pulse width Δt and relative humidity data H into the pulse width-humidity compensation model formula to fit the pulse width-humidity (Δt-H) compensation curve, and calculate the ink humidity compensation coefficient C.

[0037] Step 2.6: Input the ink temperature and humidity compensation coefficients A, B, C and the reference values ​​U0, t0, H0 into the control unit so that the piezoelectric printhead ejects ink droplets according to the corrected U and Δt; under multiple temperature and humidity conditions, the compensation coefficients are fine-tuned according to the printing effect to obtain the best printing effect, thus obtaining the final temperature and humidity compensation coefficients.

[0038] Step 2.7: When using different types of ink or printing paper, repeat steps 2.1 to 2.6 to obtain the corresponding ink temperature and humidity compensation coefficients A, B, C and reference values ​​U0, t0, H0, forming a compensation coefficient database for different types of ink and printing paper for the printer, which is then stored in the control unit to achieve automatic temperature and humidity compensation for various types of ink or printing paper.

[0039] Step 3: Input the ink temperature and humidity compensation coefficients (A, B, C) and reference values ​​(U0, t0, H0) into the control unit via the host computer. During printing, based on the temperature and humidity data fed back by the temperature and humidity acquisition unit, the control unit calculates the driving voltage and pulse width in real time, generates a driving waveform, and drives the piezoelectric printhead to eject ink droplets according to the set driving waveform via the piezoelectric drive unit. The specific printing process is as follows: Step 3.1: Select the ink type and paper type for printing.

[0040] Step 3.2: When the printing job starts, the temperature sensor at the piezoelectric printhead collects the ambient temperature value (T) at the printhead, and the humidity sensor collects the humidity value (H) at the printhead, and transmits them to the control unit.

[0041] Step 3.3: The control unit calculates the driving voltage and pulse width required for the current printing based on the collected temperature and humidity data, generates the driving waveform, and outputs it to the piezoelectric drive unit.

[0042] Step 3.4: The piezoelectric drive unit drives the piezoelectric printhead to print according to the drive waveform generated by the control unit, so as to achieve the best printing effect.

[0043] Although embodiments and drawings of the present invention have been disclosed for illustrative purposes, those skilled in the art will understand that various substitutions, variations and modifications are possible without departing from the spirit and scope of the present invention and the appended claims. Therefore, the scope of the present invention is not limited to the contents disclosed in the embodiments and drawings.

Claims

1. A printhead control system for an inkjet printer based on temperature and humidity compensation, characterized in that: It includes a temperature and humidity acquisition unit, a control unit, and a piezoelectric drive unit; The temperature and humidity acquisition unit uses a high-precision digital temperature sensor and a high-precision digital humidity sensor. The high-precision digital temperature sensor and the high-precision digital humidity sensor are arranged near the nozzle and communicate with the control unit through the IIC interface. The high-precision digital temperature sensor and the high-precision digital humidity sensor are used to acquire the ambient temperature T and relative humidity H in real time. The hardware of the control unit is implemented based on an embedded processor. The control unit is used to complete temperature and humidity data acquisition, drive waveform calculation based on temperature and humidity compensation algorithm, and drive waveform output. The piezoelectric drive unit is used to control the voltage change of the printer head through the drive waveform output by the control unit, and output a trapezoidal wave with adjustable amplitude and duty cycle to drive the print head to eject ink droplets.

2. The inkjet printer printhead control system based on temperature and humidity compensation according to claim 1, characterized in that: The control unit includes a temperature and humidity data acquisition module, a drive waveform calculation module, and a drive waveform output module; wherein, the temperature and humidity data acquisition module communicates with a high-precision digital temperature sensor and a high-precision digital humidity sensor through an IIC interface to acquire temperature and humidity data near the nozzle. The drive waveform calculation module includes a voltage compensation module and a pulse width compensation module. The voltage compensation module dynamically adjusts the voltage amplitude of the drive waveform based on the collected temperature information according to the drive voltage-temperature compensation model. The pulse width compensation module dynamically adjusts the pulse width of the drive waveform based on the collected humidity information according to the pulse width-humidity compensation model. The drive waveform calculation function module supports a parameter calibration interface, which can input ink temperature and humidity compensation coefficients A, B, C and reference values ​​U0, t0, H0 through a host computer; where A is the temperature compensation coefficient, B is the ink characteristic constant, and C is the humidity compensation coefficient. The drive waveform output function module communicates with the piezoelectric drive unit and outputs the drive waveform generated by the drive waveform calculation function module to the piezoelectric drive unit.

3. A printhead control method for an inkjet printer based on temperature and humidity compensation, employing the inkjet printer printhead control system based on temperature and humidity compensation as described in claim 1 or 2, comprising the following steps: Step 1: Establish the drive voltage-temperature compensation model and pulse width-humidity compensation model through the drive waveform calculation function module of the control unit; Step 2: By calibrating the driving voltage and driving waveform for optimal printing effect under different temperatures and humidity, the driving voltage-temperature and pulse width-humidity are fitted into curves that conform to the formula, and the ink temperature and humidity compensation coefficients A, B, and C are obtained. Step 3: Input the ink temperature and humidity compensation coefficients (A, B, C) and reference values ​​(U0, t0, H0) into the control unit via the host computer. During the printing process, the drive voltage and pulse width can be calculated in real time based on the temperature and humidity data fed back by the temperature and humidity acquisition unit, and a drive waveform can be generated. The piezoelectric drive unit drives the piezoelectric printhead to eject ink droplets according to the set drive waveform.

4. The inkjet printer printhead control method based on temperature and humidity compensation according to claim 3, characterized in that: In step 1: The adjustment of the driving voltage and temperature compensation voltage is based on the following formula: ； Where A1 and B are ink characteristic constants, T is absolute temperature (K), U0 is reference voltage, and η0 is reference viscosity; From the above two formulas, the following driving voltage-temperature compensation model formula can be derived: ； Where A is the temperature compensation coefficient, and its value is... B is the ink characteristic constant; The formula for the pulse width-humidity compensation model is as follows: ； Where C is the humidity compensation coefficient, H is the relative humidity, H0 is the reference relative humidity, and t0 is the reference pulse width.

5. The inkjet printer printhead control method based on temperature and humidity compensation according to claim 3, characterized in that: The calibration process in step 2 is as follows: Step 2.1: Using room temperature of 25℃ and relative humidity of 40% as the reference temperature T0 and reference humidity H0, adjust the driving voltage and pulse width under this environment, print a standard graphic, select the best printing effect, and record the driving voltage at this time as the reference voltage U0 and the pulse width as the reference width t0. Step 2.2: At a relative humidity of 40% and temperatures (T) of 15℃, 35℃, 45℃, and 55℃, adjust the driving voltage, print standard graphics, select the best printing effect, and record the driving voltage U at each time. Step 2.3: Substitute the driving voltage U and temperature data T into the driving voltage-temperature compensation model formula, fit it into the driving voltage-temperature (UT) compensation curve, and calculate the ink temperature compensation coefficients A and B; Step 2.4: At a temperature of 25℃ and relative humidity of 40%, 50%, 60%, 70%, 80%, and 90%, respectively, adjust the pulse width, print standard graphics, select the best printing effect, and record the pulse width Δt at each time. Step 2.5: Substitute the pulse width Δt and relative humidity data H into the pulse width-humidity compensation model formula, fit it into a pulse width-humidity (Δt-H) compensation curve, and calculate the ink humidity compensation coefficient C; Step 2.6: Input the ink temperature and humidity compensation coefficients A, B, C and the reference values ​​U0, t0, H0 into the control unit so that the piezoelectric printhead ejects ink droplets according to the corrected U and Δt; Under multiple temperature and humidity conditions, the compensation coefficient is fine-tuned based on the printing effect to obtain the best printing effect, thus obtaining the final temperature and humidity compensation coefficient. Step 2.7: When using different types of ink or printing paper, repeat steps 2.1 to 2.6 to obtain the corresponding ink temperature and humidity compensation coefficients A, B, C and reference values ​​U0, t0, H0, forming a compensation coefficient database for different types of ink and printing paper for the printer, which is then stored in the control unit to achieve automatic temperature and humidity compensation for various types of ink or printing paper.

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