Liquid Ejection Head Layout for Pump-Free Ink Circulation
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Solution Overview
Problem
Conventional liquid ejection heads require complex mechanisms like pressure adjustment and pumps for ink circulation, leading to increased size and complexity, and existing chip configurations fail to optimize ejection and circulation characteristics.
Innovation Solution
A liquid ejection head design incorporating a first energy generation element for ejecting liquid and a second energy generation element for circulating liquid, with specific opening configurations in individual flow passages to enhance circulation and ejection efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a differential pressure circulation method using pressure adjustment mechanisms and pumps is used, then ink circulation is achieved, but the main body of the recording apparatus and the head increase in size
Solution Approach 1:
The patent extracts the circulation function from a separate pump mechanism and integrates it into the ejection nozzles themselves through selective non-ejection. By having specific nozzles refrain from ejecting ink while others eject, a circulation flow is generated without requiring external pumps or pressure adjustment mechanisms, thus solving the contradiction between achieving ink circulation and maintaining compact size.
Solution Approach 2:
The ejection nozzles serve dual functions: they both eject ink for recording and generate circulation flow by selectively refraining from ejection. This multi-functionality eliminates the need for separate circulation mechanisms, reducing the overall size of the apparatus while maintaining effective ink circulation.
2Productivity
If conventional chip configurations with energy generation elements are used, then liquid ejection is achieved, but ejection and circulation characteristics are not optimized
Solution Approach 1:
The patent applies local quality by creating distinct zones within the nozzle array: some nozzles are configured to eject ink while adjacent nozzles are configured to refrain from ejection. This spatial differentiation in function optimizes both ejection performance (from active nozzles) and circulation characteristics (generated by the pattern of active and inactive nozzles), achieving improved productivity without increasing overall 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
Improves ejection and circulation characteristics by reducing the need for external pumps and pressure adjustment mechanisms, minimizing nozzle drying, and reducing waste ink, thereby enhancing throughput and image quality.
Implementation Method 1
a first energy generation element which generates energy for ejecting liquid from at least one ejection nozzle
Implementation Method 2
a second energy generation element which generates energy for causing the liquid to flow
Data Source
AI summary
A liquid ejection head in which a plurality of ejection nozzles is arranged in a first direction includes: a first flow passage communicating with one end of each of a plurality of individual flow passages; a second flow passage communicating with the other end of each of the plurality of individual flow passages; a plurality of first openings provided in the first flow passage; and a plurality of second openings provided in the second flow passage, in which D2>D1, in which D1 represents a size of a non-open part in a first direction between the two adjacent first openings, and D2 represents a size of a non-open part in the first direction between the two adjacent second openings.