Inkjet Printhead Compensating Member Uniform Rigidity
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Solution Overview
Problem
Inkjet printheads with constant-width common ink chambers suffer from ink stagnation and air bubble accumulation, leading to inconsistent ink ejection characteristics due to varying rigidity along the pressure chambers, which affects the speed and stability of ink droplet ejection.
Innovation Solution
A compensating member with lower rigidity than the common-chamber member is introduced in the common ink chamber, gradually decreasing its cross-sectional area away from the ink introduction point, ensuring uniform rigidity support for pressure chambers and preventing ink stagnation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the common ink chamber has a constant width throughout its length, then the structure is simple and easy to manufacture, but ink flow stagnation occurs at the remote end leading to air bubble accumulation and ejection failure
Solution Approach 1:
The patent applies local quality by varying the cross-sectional area of the common ink chamber along its length. Specifically, the chamber has a larger cross-sectional area at the ink introduction end and a gradually decreasing area toward the remote end. This local variation in geometry creates a flow acceleration effect that prevents ink stagnation and air bubble accumulation at the remote end, thereby maintaining reliable ink ejection while accepting increased manufacturing complexity.
2Reliability
If the common ink chamber cross-sectional area is gradually reduced at the remote end to prevent ink stagnation, then ink flow stability improves, but the rigidity of the manifold plate varies along the longitudinal direction causing non-uniform pressure wave propagation
Solution Approach 1:
The patent applies parameter changes by carefully controlling the cross-sectional area variation of the common ink chamber. The design ensures that while the area decreases to prevent stagnation, the reduction is gradual and controlled to minimize the impact on manifold plate rigidity. This parameter optimization balances ink flow stability with structural rigidity uniformity, ensuring that pressure wave propagation remains sufficiently consistent across all pressure chambers.
3Speed
If the cross-sectional area of the common ink chamber is decreased at the remote portion, then ink flow velocity increases preventing stagnation, but the supporting rigidity of the common-chamber member decreases
Solution Approach 1:
The patent applies local quality by strategically placing the compensating member only at the remote portion of the common ink chamber where the cross-sectional area is decreased. This localized reinforcement provides additional supporting rigidity exactly where needed to compensate for the reduced structural strength, while allowing the ink flow velocity to remain high in this same region to prevent stagnation. The compensating member thus locally addresses the rigidity deficiency without affecting the overall flow dynamics.
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 arrangement prevents ink stagnation and air bubble accumulation, resulting in uniform ink ejection characteristics across all pressure chambers, enhancing print quality by maintaining consistent droplet speed and stability.
Implementation Method 1
as the ink introduced at the ink introduction place flows in the common ink chamber toward the second longitudinal end, the ink flow decelerates, and stagnation of the ink flow tends to occur
Implementation Method 2
The piezoelectric actuator unit is disposed on the cavity unit so as to selectively pressurize the ink in the pressure chambers, to eject droplets of the ink from the nozzles as desired
Implementation Method 3
the characteristic period of propagation of a pressure wave in the ink through an ink channel which is partially constituted by each pressure chamber
Data Source
AI summary
An inkjet printhead includes: a cavity unit having aligned nozzles, pressure chambers correspondingly aligned, and a common-chamber member having a common chamber connected, at an introduction place, to an ink source to receive and distribute ink to the pressure chambers, and extending along the pressure chambers row to overlap each pressure chamber when seen in the superposition direction, and a cross-sectional area of the common chamber perpendicular to its longitudinal direction gradually decreases in a direction away from the introduction place, at a portion remote from the introduction place; an actuator on the cavity unit to pressurize the distributed ink to eject ink droplets from the nozzles; and a compensating member having a rigidity lower than that of the common-chamber member, and being disposed in contact with the ink, at the remote portion so that a supporting rigidity of the common-chamber member is substantially uniform along the pressure chambers row.