Liquid Discharge Head Filling to Prevent Chamber Bubbles
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Solution Overview
Problem
Existing liquid discharge apparatuses, such as those using the inkjet method, suffer from instability due to bubble generation in the liquid storage chamber during liquid supply.
Innovation Solution
A liquid discharge apparatus with a supply unit that alternately supplies two types of liquids with specific properties, including a first liquid with a low contact angle and low surface tension to prevent bubble formation, followed by a second liquid, and optionally includes a drain process to remove residual first liquid, all controlled by a controller to stabilize the discharge process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If liquid is supplied to the liquid discharge head using conventional methods, then the liquid discharge function is provided, but bubbles are generated in the liquid storage chamber causing unstable discharge
Solution Approach 1:
A supply liquid with specific properties (surface tension of 15-30 mN/m and contact angle of 0-60 degrees) is introduced as an intermediary substance to replace the conventional supply liquid. This intermediary liquid prevents bubble generation by improving wetting properties and reducing surface tension, thereby stabilizing the liquid discharge without affecting the primary discharge function
Solution Approach 2:
The surface tension and contact angle parameters of the supply liquid are specifically modified to resolve the contradiction. By controlling the surface tension within 15-30 mN/m and contact angle within 0-60 degrees, the liquid achieves optimal wetting properties that prevent bubble formation while maintaining stable discharge operation
2Reliability
If a supply liquid is used to prevent bubble generation, then discharge stability is improved, but additional liquid supply steps and liquid types are required
Solution Approach 1:
The supply liquid serves multiple functions simultaneously: it prevents bubble generation, stabilizes the liquid discharge, and prepares the liquid storage chamber for optimal discharge conditions. This multi-functional approach eliminates the need for separate bubble removal mechanisms or additional complex control systems
Solution Approach 2:
By precisely controlling the surface tension and contact angle parameters of the supply liquid, the system achieves stable discharge with a simple liquid supply mechanism, avoiding the need for complex mechanical or structural modifications
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
Stable liquid discharge is achieved by preventing bubble generation and ensuring uniform distribution of liquids, thereby maintaining consistent operation.
Implementation Method 1
a first liquid having a contact angle with an upper surface of the MEMS chip of less than 90 degrees is supplied to the liquid discharge unit as a first supply process
Implementation Method 2
The first liquid having a low contact angle and low surface tension is used to prevent bubble formation
Data Source
Figure 1
Figure 2A~3
Figure 4~5
AI summary
A liquid discharge apparatus (100) includes a liquid discharge unit (1). The liquid discharge unit (1) includes a liquid chamber member (11) defining a liquid holding portion (14) to hold a liquid, a film (132) having a nozzle hole (132a) from which the liquid is discharged and a surface (132b) facing the liquid holding portion (14), and a holder (131) supporting the film (132). The surface (132b) of the film (132) has a contact angle with water of less than 90 degrees.