Ink Jet Head Drive Signal Acoustic Resonance Control
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Solution Overview
Problem
Existing ink jet heads face challenges in achieving efficient droplet discharge with high power consumption and limited cost-effectiveness, particularly in maintaining consistent droplet velocity and landing accuracy across multiple droplets.
Innovation Solution
The ink jet head incorporates a pressure chamber with an actuator that applies a drive signal comprising a first discharge pulse, a second discharge pulse, and a vibration pulse, where the vibration pulse generates pressure vibration to enhance droplet discharge, and the pulse widths and timing are optimized relative to the main acoustic resonance frequency to improve discharge efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a multi-drop ink jet head discharges multiple droplets per dot to adjust droplet amount, then droplet quantity control is improved, but power consumption increases
Solution Approach 1:
The drive signal uses periodic pulse waves with specific timing relationships. The first and second discharge pulses are periodic signals that discharge multiple droplets, while the vibration pulse is a periodic signal that resonates with the liquid's acoustic frequency to enhance discharge efficiency. This periodic action allows multiple droplets to be discharged with optimized energy input compared to continuous driving.
Solution Approach 2:
The invention changes the temporal parameters of the drive signal, specifically setting the period between discharge pulses to 1.5-2.5 times the half-period of the liquid's acoustic resonance frequency, and adjusting pulse widths to be close to the half-period. These parameter changes optimize the energy efficiency of multi-drop discharge by leveraging acoustic resonance.
2Speed
If discharge pulses are applied to control droplet velocity, then droplet discharge control is improved, but landing accuracy deteriorates due to velocity inconsistency
Solution Approach 1:
The vibration pulse is applied before the discharge pulses to preliminarily excite acoustic resonance in the liquid. This preliminary action prepares the liquid medium by creating pressure vibrations that will enhance and stabilize the subsequent droplet discharge, ensuring consistent droplet velocity and improving landing accuracy.
Solution Approach 2:
The invention uses mechanical vibration in the form of acoustic resonance. The vibration pulse generates pressure vibrations in the liquid at its acoustic resonance frequency, and the discharge pulses are timed to coincide with these vibrations. This mechanical vibration approach ensures that droplets are discharged with consistent velocity, improving landing accuracy.
3Device complexity
If standard discharge pulses are used without vibration pulse, then device complexity is reduced, but droplet discharge force is insufficient
Solution Approach 1:
The vibration pulse introduces mechanical vibration in the form of acoustic resonance without adding physical components. By timing the discharge pulses to coincide with the resonant vibrations, the droplet discharge force is significantly enhanced while maintaining a relatively simple drive signal structure consisting of three electronic pulses.
Solution Approach 2:
The invention optimizes the temporal parameters of the drive signal: the vibration pulse width and the period between discharge pulses are both set to 1.5-2.5 times the half-period of the liquid's acoustic resonance frequency. These parameter changes maximize the discharge force by leveraging resonance while keeping the drive signal structure simple.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration reduces power consumption, enhances droplet discharge force, and maintains consistent droplet velocity, leading to improved landing accuracy and image quality while allowing for lower manufacturing costs.
Implementation Method 1
a period between a center of the first discharge pulse and a center of the second discharge pulse is 1.5 times to 2.5 times a half-period of a main acoustic resonance frequency of the liquid in the pressure chamber
Implementation Method 2
a vibration pulse that is applied before the first discharge pulse and has a potential difference having a polarity opposite to that of the first discharge pulse and the second discharge pulse, and causes a pressure vibration to be generated in the liquid to promote discharge of the liquid
Data Source
Figure 1
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AI summary
An ink jet head includes a pressure chamber, an actuator, and an application unit. The chamber accommodates liquid. The actuator changes a volume of the chamber with a drive signal to be applied. The unit apply s the signal to the actuator. The signal includes a discharge pulse and a vibration pulse. The discharge pulse causes liquid to be discharged from a nozzle. A second discharge pulse is applied after a first discharge pulse. The vibration pulse is applied before the discharge pulse, has a potential difference having a polarity opposite to that of the discharge pulse. A period of the discharge pulse is 1.5 times to 2.5 times a half-period of a main acoustic resonance frequency of liquid in the chamber. A pulse width of the first pulse is closer to the half-period of the main acoustic resonance frequency than a pulse width of the second pulse.