Piezoelectric Liquid Ejection Head for Uniform Pressure Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing piezoelectric actuators in liquid ejection heads face inefficiencies in pressure application and liquid ejection control, particularly in the distribution and polarization of piezoelectric layers, leading to suboptimal printing quality and performance.
Innovation Solution
A liquid ejection head design featuring a piezoelectric actuator with specific polarization directions and active portions, combined with a channel member and conductor layers, to enhance pressure application and liquid ejection control, allowing for precise droplet formation and improved printing capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a voltage is applied to the piezoelectric layers and diaphragm in conventional piezoelectric actuators, then liquid ejection is achieved, but the pressure distribution is uneven and ejection control is suboptimal
Solution Approach 1:
The piezoelectric actuator is divided into multiple independent piezoelectric elements (first, second, third, and fourth elements) corresponding to different regions of the pressure chamber. Each element can be controlled independently to apply voltage to specific areas (central portion, outer circumferential portions, bottom surface), enabling precise control of pressure distribution and liquid ejection across different regions of the nozzle plate.
Solution Approach 2:
Different piezoelectric elements are positioned to provide localized pressure control: first and second elements address the central portion, third and fourth elements address outer circumferential portions, and additional elements address the bottom surface. This localized arrangement allows each region to receive optimized pressure control tailored to its specific ejection requirements, improving overall uniformity and precision.
2Manufacturing precision
If conventional piezoelectric layer distribution is used, then the structure is simple, but printing quality and resolution are limited
Solution Approach 1:
The piezoelectric actuator structure is segmented into multiple elements with distinct positions and functions. This segmentation enables independent control of different pressure regions, allowing for high-resolution liquid ejection patterns and improved printing quality, while the modular design keeps the overall structure manageable.
Solution Approach 2:
The multiple piezoelectric elements work together as an integrated system to achieve multiple functions: central region control for primary ejection, outer circumferential control for edge refinement, and bottom surface control for pressure distribution optimization. This multi-functionality enables high-quality printing without requiring separate actuators for each function.
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
The design achieves enhanced printing quality and performance by optimizing pressure distribution and liquid ejection, enabling high-resolution and high-speed printing with reduced defects.
Implementation Method 1
The piezoelectric layers expand and contract along a surface. Thus, the piezoelectric actuator, like a bimetal, undergoes bending and deformation. The pressure chamber receives pressure accordingly, and as a result, the liquid is ejected from the pressure chamber.
Implementation Method 2
Patent Literature 3 and Patent Literature 4 disclose techniques by which an electric field is applied to conduct poling process. The first active portion is polarized in a direction parallel to the electric field generated in the first active portion, and the second active portion is polarized in a direction opposite to the electric field generated in the second active portion.
Data Source
Figure 1A~1B
Figure 2
Figure 3
AI summary
A piezoelectric actuator includes a first active region and a second active region. The first active region is made of a piezoelectric member polarized in a thickness direction and overlaps a midsection of a pressure chamber when viewed in plan through a pressure applying surface. The second active region is made of a piezoelectric member polarized in the thickness direction and closer than the first active region to the pressure applying surface. The second active region extends over both a peripheral section of the pressure chamber and an outer region located outside the pressure chamber when viewed in plan through the pressure applying surface. When performing liquid ejection control, a driver controls intensity of a first electric field applied to the first active region and intensity of a second electric field applied to the second active region such that the time period over which the first active region expands and the time period over which the second active region expands overlap or coincide with each other and the time period over which the first active region contracts and the time period over which the second active region contracts overlap or coincide with each other. The first electric field is more intense than the second electric field.