Liquid Ejection Head Symmetric Circulation Outlets
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Solution Overview
Problem
Inkjet heads with individual circulation channels adjacent to nozzle openings experience uneven ejection pressure and viscosity gradients, leading to unstable ejection bending due to liquid circulation, which existing technologies fail to adequately address.
Innovation Solution
The design includes a nozzle with symmetrically arranged circulation outlets and individual circulation channels that communicate with a common circulation channel, ensuring equal flow rates through each outlet, thereby stabilizing the ink flow and preventing ejection bending.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an individual circulation channel is arranged adjacent to a nozzle opening to suppress viscosity increase, then liquid circulation is improved, but ejection pressure becomes uneven causing ejection bending
Solution Approach 1:
The circulation outlet is positioned asymmetrically at a specific distance from the nozzle opening rather than adjacent to it. This asymmetric arrangement allows liquid circulation to suppress viscosity increase while maintaining sufficient distance to prevent uneven ejection pressure and ejection bending, thus resolving the contradiction between circulation effectiveness and ejection accuracy.
Solution Approach 2:
The distance between the circulation outlet and nozzle opening is optimized as a critical parameter. By setting this distance to a specific value range, the patent achieves both effective liquid circulation for viscosity control and adequate separation to maintain uniform ejection pressure, thereby preventing ejection bending while ensuring reliable circulation.
2Reliability
If liquid circulation is implemented to prevent ejection failure, then ejection reliability is improved, but viscosity gradient becomes unstable causing irregular ejection bending
Solution Approach 1:
The asymmetric positioning of the circulation outlet at an optimized distance from the nozzle opening creates a stable flow pattern. This configuration ensures consistent liquid circulation that maintains stable viscosity gradient, preventing irregular ejection bending while preserving ejection reliability.
Solution Approach 2:
The circulation outlet arrangement creates a balanced flow field where viscosity distribution becomes uniform and stable. By positioning the outlet at the optimal distance, the system achieves equipotential conditions for viscosity distribution, eliminating unstable viscosity gradients that cause irregular ejection bending.
Data Source
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AI summary
A liquid ejection head includes: a nozzle including a nozzle opening and a nozzle communication channel communicating at one end thereof with the nozzle opening; a liquid chamber communicating with another end of the nozzle communication channel; a pressurizing element configured to pressurize liquid in the liquid chamber; circulation outlets formed at the nozzle; individual circulation channels communicating with the nozzle; and a common circulation channel at which communication ports respectively communicating with the individual circulation channels are formed, the circulation outlets arranged symmetrically with respect to a nozzle axis passing through a barycenter of the nozzle opening and perpendicular to a nozzle opening surface, and the individual circulation channels respectively communicating with the circulation outlets and a same common circulation channel, flow rates of liquid respectively passing through the circulation outlets when the liquid in the nozzle is circulated to the common circulation channel being equal to each other.