Piezoelectric Inkjet Head Segmentation for Discharge Stability
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Solution Overview
Problem
Existing liquid discharge apparatuses, such as piezo-type ink jet printers, face challenges in maintaining stable discharge characteristics due to deterioration of piezoelectric elements and manufacturing errors, leading to inconsistent ink discharge.
Innovation Solution
The liquid discharge apparatus incorporates a diaphragm with a piezoelectric element that includes a first active portion overlapping the center of the pressure chamber and a second active portion closer to the outer edge. A drive signal generation portion supplies a discharge signal to one active portion and a correction signal to the other, with the potential of the discharge signal changing over time and the correction signal maintaining a constant potential during the discharge period.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a piezoelectric element is used to discharge liquid from the nozzle, then liquid discharge function is achieved, but discharge characteristics deteriorate over time due to piezoelectric body deterioration and manufacturing errors
Solution Approach 1:
The piezoelectric element is divided into multiple independent active portions (first active portion and second active portion) positioned at different locations on the diaphragm. This segmentation allows independent control and compensation of each portion, enabling correction of discharge characteristics without replacing the entire piezoelectric element, thus extending service life while maintaining reliability.
Solution Approach 2:
The invention changes the electrical parameters (potential values) of the discharge signal and correction signal applied to different active portions of the piezoelectric element. By adjusting these parameters over time, the system compensates for deterioration and manufacturing variations, maintaining stable discharge characteristics throughout the service life.
2Manufacturing precision
If a single piezoelectric element is used for liquid discharge, then device structure is simple, but discharge characteristics vary due to manufacturing errors
Solution Approach 1:
The piezoelectric element is segmented into multiple active portions with different potentials, allowing compensation for manufacturing variations in each region. This segmentation enables precise control of diaphragm deformation across different areas, improving discharge consistency without requiring a completely more complex device structure.
Solution Approach 2:
Different active portions of the piezoelectric element are assigned different electrical characteristics (potentials) to compensate for local manufacturing variations. The first active portion and second active portion have different potential values that are optimized for their specific locations on the diaphragm, achieving uniform discharge characteristics across the device.
3Stability of the object's composition
If correction signal with constant potential is applied to piezoelectric element, then diaphragm tension is stabilized, but energy consumption increases
Solution Approach 1:
The correction signal is applied periodically or only during specific discharge periods rather than continuously. By timing the correction signal application to coincide with discharge operations, the system maintains diaphragm tension stability when needed while minimizing energy consumption during idle periods.
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 allows for stable and consistent ink discharge characteristics by adjusting the tension of the diaphragm using the correction signal, thereby reducing the impact of piezoelectric element deterioration and manufacturing variations.
Implementation Method 1
a piezoelectric element that includes a first active portion laminated on the second surface and that overlaps a center of the pressure chamber when viewed in a thickness direction of the diaphragm
Data Source
AI summary
A liquid discharge apparatus includes a diaphragm, a pressure chamber substrate including a partition wall partitioning a pressure chamber communicating with a nozzle discharging liquid, a piezoelectric element including a first active portion that overlaps a center of the pressure chamber and a second active portion that overlaps the pressure chamber at a position closer to an outer edge of the pressure chamber than the first active portion, and a drive signal generation portion that generates a discharge signal for discharging the liquid by being supplied to one of the first active portion and the second active portion and a correction signal that is supplied to the other of the first active portion and the second active portion, in which a potential of the discharge signal changes over time and a potential of the correction signal is constant during a discharge period for discharging the liquid.