Liquid Ejecting Head Flow Path Cross-Sectional Area Design
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Solution Overview
Problem
Ink jet type recording heads and liquid ejecting heads face issues with discharge defects due to air bubbles and thickened ink causing nozzle clogging and deviation in ink droplet direction, which existing configurations fail to adequately address.
Innovation Solution
A liquid ejecting head design featuring a flow path substrate with a nozzle plate, a piezoelectric actuator, and a specific configuration of common and individual flow paths that includes a first and second common liquid chamber, where the nozzle communicates with a first flow path having varying cross-sectional areas to facilitate ink circulation and prevent thickened ink and air bubbles from accumulating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If a first common liquid chamber and a second common liquid chamber are provided with circulation from the first to the second through individual flow paths, then ink circulation is achieved, but discharge defects occur such as thickened ink near the nozzle, nozzle clogging by air bubbles, and deviation in ink droplet flying direction
Solution Approach 1:
The first flow path is designed with a first cross-sectional area on the side closer to the second flow path than the nozzle, and a second cross-sectional area smaller than the first cross-sectional area on the side opposite to the second flow path across the nozzle. This non-uniform cross-sectional area distribution creates different flow characteristics in different regions of the same flow path, allowing the patent to achieve both ink circulation and prevention of discharge defects by optimizing local flow conditions
2Ease of manufacture
If the first flow path has a uniform cross-sectional area, then manufacturing is simpler, but ink circulation efficiency is reduced and thickened ink accumulates
Solution Approach 1:
The first flow path incorporates a first cross-sectional area and a second cross-sectional area with different sizes at different locations. This local variation in cross-sectional area optimizes ink circulation efficiency while preventing accumulation of thickened ink, resolving the contradiction between manufacturing simplicity and circulation effectiveness
3Speed
If the cross-sectional area of the first flow path is increased, then ink flow rate increases, but air bubbles more easily infiltrate from the nozzle and cause clogging
Solution Approach 1:
The first flow path has a first cross-sectional area on the side closer to the second flow path and a second cross-sectional area smaller than the first on the side opposite to the second flow path across the nozzle. This asymmetric design allows the patent to maintain adequate ink flow rate while creating flow conditions that prevent air bubble infiltration and subsequent nozzle clogging
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 design effectively prevents discharge defects by ensuring ink thickened by the nozzle flows to a downstream region, reducing pressure loss, and preventing air bubbles from entering the pressure chamber, thereby maintaining consistent ink droplet discharge.
Implementation Method 1
an energy generating element such as a piezoelectric actuator that induces a change in the pressure of the ink in the pressure chamber
Data Source
AI summary
The first flow path includes a portion having a first cross-sectional area on a side that is closer to the second flow path than the nozzle, and a portion having a second cross-sectional area, which is smaller than the first cross-sectional area, on a side that is opposite to the second flow path across the nozzle.