Liquid Ejecting Head With Asymmetric Bypass Resistance
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Solution Overview
Problem
The relationship between the flow path resistances of bypass flow paths in liquid ejecting heads is not sufficiently considered, leading to inefficiencies in liquid distribution and recovery.
Innovation Solution
A liquid ejecting head design with distinct flow path resistances in bypass flow paths, where the inlet and outlet are positioned between the bypass flow paths in the same direction, and a circulation mechanism for circulating liquid between the head and a storage portion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If bypass flow paths are provided at both ends of the supply side common liquid chamber and recovery side common liquid chamber, then liquid circulation is improved, but flow path resistance imbalance occurs leading to inefficient liquid distribution
Solution Approach 1:
The patent applies asymmetry by intentionally designing the bypass flow paths with different flow path resistances. The first bypass flow path has a different flow path resistance than the second bypass flow path, creating an asymmetric flow distribution that optimizes liquid circulation. This asymmetric design allows the system to achieve better overall liquid distribution efficiency by compensating for pressure imbalances in the common liquid chambers.
Solution Approach 2:
The patent implements local quality by positioning the liquid inlet and liquid outlet at specific locations between the bypass flow paths. The inlet is positioned to supply liquid to the supply side common liquid chamber in a manner that accounts for the different flow path resistances, while the outlet is positioned to efficiently collect liquid from the recovery side common liquid chamber. This localized optimization of inlet/outlet positions works in conjunction with the asymmetric bypass resistances to achieve balanced liquid distribution.
2Device complexity
If the liquid inlet and outlet are positioned at the center in the longitudinal direction, then structural symmetry is achieved, but flow distribution efficiency is reduced due to bypass flow path resistance differences
Solution Approach 1:
The patent deliberately introduces asymmetry in the flow path resistances of the bypass flow paths to compensate for the symmetric positioning of the inlet and outlet. By making the first bypass flow path resistance different from the second bypass flow path resistance, the system achieves efficient liquid distribution despite the symmetric inlet/outlet positioning. This asymmetric resistance design allows liquid to be distributed more effectively through the nozzle rows.
3Ease of manufacture
If bypass flow paths with equal flow path resistances are used, then manufacturing simplicity is maintained, but liquid recovery efficiency is reduced
Solution Approach 1:
The patent applies asymmetry by designing bypass flow paths with different flow path resistances to optimize liquid recovery efficiency. The first bypass flow path connects the end portion of the supply side common liquid chamber to the end portion of the recovery side common liquid chamber, while the second bypass flow path connects opposite end portions. By making their flow path resistances different, the system achieves more efficient liquid recovery and circulation, improving overall productivity despite increased manufacturing complexity.
Data Source
AI summary
An individual flow path that communicates with a nozzle, a supply side common liquid chamber for supplying ink to the nozzle, a recovery side common liquid chamber for recovering the ink not discharged from the nozzle, an inlet that communicates with the supply side common liquid chamber, an outlet that communicates with the recovery side common liquid chamber, a first bypass flow path, and a second bypass flow path are provided, in which the inlet and the outlet are disposed between the first bypass flow path and the second bypass flow path, and a flow path resistance of the first bypass flow path and a flow path resistance of the second bypass flow path are different from each other.