Liquid Discharge Head Temperature Sensing for Piezoelectric Deterioration
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Solution Overview
Problem
Existing liquid discharge devices, such as piezo ink jet printers, fail to accurately assess the degree of deterioration of piezoelectric bodies due to variations caused by manufacturing errors and temperature, leading to inaccurate discharge control.
Innovation Solution
Incorporation of a detection resistor near the pressure chamber to measure temperature and a decision section to determine the degree of piezoelectric body deterioration based on temperature detection, allowing for precise assessment and adjustment of drive signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the degree of deterioration of the piezoelectric body is assessed based on the number of times of discharge, then the assessment can be performed using simple counting, but the assessment accuracy is poor due to variations caused by manufacturing errors and temperature
Solution Approach 1:
The patent introduces a detection resistor as an intermediary element to indirectly measure the piezoelectric body's deterioration. Instead of directly measuring the piezoelectric body's displacement (which is difficult and sensitive to environmental factors), the detection resistor measures temperature changes caused by heat generation during piezoelectric operation. This intermediary measurement approach provides a more stable and accurate indicator of deterioration without requiring complex direct measurement systems.
Solution Approach 2:
The patent replaces the mechanical/displacement-based deterioration assessment with a thermal/electrical measurement system. By substituting the direct mechanical measurement of piezoelectric displacement with temperature detection through the detection resistor, the system achieves more reliable deterioration assessment that is less susceptible to manufacturing variations and environmental factors.
2Reliability
If no detection resistor is provided, then the device structure remains simple, but the temperature-related variations in piezoelectric body performance cannot be compensated
Solution Approach 1:
The patent implements a feedback mechanism where the detection resistor continuously monitors temperature changes during piezoelectric body operation. This temperature information is fed back to the control system, which then adjusts the drive signal to compensate for temperature-induced variations in piezoelectric body performance. This closed-loop feedback ensures stable and reliable discharge control despite temperature fluctuations.
3Productivity
If the piezoelectric body is repeatedly driven, then the liquid discharge device maintains continuous operation, but the piezoelectric body deteriorates over time
Solution Approach 1:
The patent applies preliminary action by monitoring the piezoelectric body's condition through the detection resistor before significant deterioration occurs. The continuous temperature monitoring allows the system to detect early signs of deterioration and take preventive measures, such as adjusting drive parameters or alerting the user, thereby maintaining reliable operation throughout the piezoelectric body's service life.
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
Enables accurate monitoring and adjustment of piezoelectric body deterioration, improving discharge consistency and quality in liquid discharge devices.
Implementation Method 1
a detection resistor for detecting a temperature in a vicinity of the first pressure chamber
Implementation Method 2
a piezoelectric body for applying pressure to the liquid in the pressure chamber
Data Source
AI summary
A liquid discharge device has a liquid discharge head that includes a pressure chamber substrate provided with a first pressure chamber in which a liquid is accommodated, a first piezoelectric body provided to correspond to the first pressure chamber, and a detection resistor for detecting a temperature in a vicinity of the first pressure chamber, and a decision section that decides a degree of deterioration of the first piezoelectric body based on a detection result of the detection resistor.