Liquid Ejection Head Dummy Channel Ink Circulation
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Solution Overview
Problem
The quality of liquid in dummy channels of liquid ejection heads can deteriorate over time due to exposure to the atmosphere, affecting the uniformity and efficiency of liquid ejection characteristics among channels.
Innovation Solution
Incorporating a dummy channel with a pressure chamber, actuator, communication passage, and circulation passage that allows ink to circulate back into the manifold, maintaining the quality of ink and preventing thickening, while using a driver integrated circuit to output specific drive signals that manage the volume changes in the pressure chamber and inertance of the passages to control ink flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a dummy channel with nozzle is added to draw liquid through the manifold, then liquid circulation and spreading is improved, but liquid quality deteriorates due to atmospheric exposure
Solution Approach 1:
The patent extracts the harmful function (atmospheric exposure causing quality deterioration) from the dummy channel while preserving its useful function (liquid circulation). This is achieved by providing a circulation passage that connects the dummy channel back to the manifold, creating a closed loop that prevents liquid from being exposed to the atmosphere through the dummy nozzle, thus resolving the contradiction between circulation efficiency and liquid quality maintenance
2Reliability
If circulation passage is added to dummy channel, then liquid quality is maintained, but device complexity increases
Solution Approach 1:
The patent merges the circulation function into the existing dummy channel structure by integrating a circulation passage that connects the dummy channel to the manifold. This combines the dummy channel's original circulation role with a new quality-maintenance function, achieving liquid quality preservation without requiring a completely separate system, thus managing the trade-off between reliability improvement and device complexity
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 solution maintains the quality of ink in the dummy channel, preventing deterioration and ensuring uniform ejection characteristics among all channels, thereby enhancing the reliability and performance of the liquid ejection head.
Implementation Method 1
Upon application of pressure to liquid in the pressure chamber, liquid is ejected from the nozzle
Implementation Method 2
a circulation passage through which the pressure chamber communicates with the manifold
Data Source
AI summary
A liquid ejection head includes a manifold configured to store liquid therein, a plurality of ejection channels, and a dummy channel. Each ejection channel communicates with the manifold and is configured to receive liquid from the manifold and eject liquid through a corresponding nozzle thereof open to a nozzle surface. The dummy channel communicates with the manifold and includes a dummy nozzle open to the nozzle surface. The dummy channel further includes a pressure chamber, an actuator configured to apply pressure to liquid in the pressure chamber, a communication passage connecting the manifold to the pressure chamber, and a circulation passage through which the pressure chamber communicates with the manifold. The circulation passage is different from the communication passage and located between the dummy nozzle and the manifold.