Discharge Head Flat Piezoelectric Actuator Bubble Prevention
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Solution Overview
Problem
Existing discharge heads, such as the Gould-type ink jet head, face challenges in efficiently applying pressure to glass tubes, leading to increased costs and reduced yield due to the need for precise matching of the inner diameter of the piezoelectric element with the glass tube, and struggle with preventing bubble formation and blockages when discharging a wide range of liquid substances.
Innovation Solution
A discharge head featuring a tubular member with a flat, oblate-shaped cross-section and a plate-like actuator, allowing for varying internal volume and efficient pressure transmission, reducing bubble formation and blockages, and enabling the use of a single glass tube for the nozzle and cavity, which can be formed at lower costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a cylindrical piezoelectric element is used in a Gould-type ink jet head, then the liquid can be discharged effectively, but the inner diameter must be precisely matched to the glass tube diameter, increasing manufacturing cost and reducing yield
Solution Approach 1:
The invention divides the piezoelectric element into two separate components: a cylindrical piezoelectric element and a flat piezoelectric element. The cylindrical element maintains its traditional role in generating pressure, while the flat element is attached to the outer surface of the glass tube to provide additional pressure application. This segmentation allows each element to be manufactured independently with standard tolerances, eliminating the need for precise diameter matching between the piezoelectric element and glass tube.
Solution Approach 2:
The flat piezoelectric element acts as an intermediary between the pressure generation mechanism and the glass tube. By attaching this flat element to the outer surface of the glass tube, the pressure is transmitted more effectively and uniformly to the liquid, improving discharge effectiveness without requiring precise dimensional matching between the piezoelectric element and the tube.
2Reliability
If a glass tube is used as the tubular member, then chemical resistance to acids and solvents is achieved, but bubble formation and blockages occur when discharging high viscosity and high surface tension liquids
Solution Approach 1:
The invention segments the pressure application mechanism into cylindrical and flat piezoelectric elements, allowing for optimized pressure distribution. The flat element specifically addresses bubble formation by providing uniform pressure across the glass tube surface, preventing blockages in high viscosity and high surface tension liquids while maintaining the chemical resistance benefits of using glass.
3Force
If the inner diameter of the piezoelectric element is made only slightly larger than the glass tube diameter, then pressure can be applied effectively, but the range of applicable tube diameters is limited, reducing adaptability
Solution Approach 1:
By separating the piezoelectric element into cylindrical and flat components, the invention decouples the pressure generation function from the pressure application function. The cylindrical element generates pressure while the flat element applies it uniformly to the glass tube surface, enabling effective pressure application across a wide range of tube diameters without requiring precise dimensional matching.
Solution Approach 2:
The flat piezoelectric element serves multiple functions: it provides uniform pressure distribution, compensates for variations in glass tube diameter, and maintains effective pressure application across different tube sizes. This universal component allows the same piezoelectric assembly to work with various glass tube diameters, significantly improving adaptability.
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 solution effectively prevents bubble formation and blockages, allowing for the discharge of a wide variety of liquid substances, including high viscosity and high surface tension liquids, while being cost-effective and resistant to acids and solvents, thus enhancing the compatibility and efficiency of the discharge head.
Implementation Method 1
a piezoelectric element that uses PZT (lead zirconate titanate) or the like
Data Source
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AI summary
There is provided a discharge head (10) including: a tubular member (20) that includes a flat portion (23) with an oblate shape where a cross-section of a tube path extends in a first direction (100x), the tubular member being formed so that the flat portion (23) includes a first wall (23a) that is flat and has an actuator (6) attached to an outside thereof and the flat portion becomes a cavity (13) with an internal volume thereof varying due to displacement of the first wall (23a); and a nozzle opening (11) that is provided at one end of the tubular member (20) and discharges a liquid substance (9) due to variation in the internal volume of the cavity (13).