Liquid-Ejecting Head Circulation Channel Design
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Solution Overview
Problem
Ink jet recording heads face issues with viscosity increase and component deposition near the nozzle opening, leading to inconsistent ink ejection quality over time, despite existing solutions that attempt to circulate ink through common liquid chambers.
Innovation Solution
A liquid-ejecting head design featuring a communication plate with a circulation channel that connects pressure-generating chambers to a common liquid chamber, allowing for continuous circulation of ink near the nozzle opening, reducing viscosity increase and component deposition, and incorporating a structure that enhances circulation characteristics without the need for additional pumps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a common liquid chamber is used to circulate ink through multiple pressure-generating chambers, then ink circulation is achieved, but the viscosity of ink near the nozzle opening still increases and component deposition cannot be sufficiently suppressed
Solution Approach 1:
The patent divides the liquid circulation system into separate circulation channels for each pressure-generating chamber, rather than using a single common liquid chamber. This segmentation allows each chamber to have its own dedicated circulation path, ensuring that fresh ink continuously flows to each nozzle opening and preventing the accumulation of viscous ink and deposited components near the ejection point.
Solution Approach 2:
The patent introduces a liquid circulation channel as an intermediary pathway between the liquid supply and the pressure-generating chambers. This circulation channel acts as a mediator that continuously transports ink from the supply through the chambers and back, preventing direct stagnation near the nozzle openings and maintaining consistent ink properties for ejection.
2Productivity
If additional pumps are added to enhance liquid circulation, then circulation effectiveness is improved, but device complexity and production costs increase
Solution Approach 1:
The patent designs the circulation system to be self-driven by the pressure-generating chambers themselves. The pressure changes generated during normal ink ejection operations naturally drive the circulation of ink through the circulation channels, eliminating the need for external pumps or additional driving mechanisms. The system uses its own operational pressure variations to maintain continuous ink circulation.
Solution Approach 2:
The pressure-generating chambers serve dual functions: they generate pressure for ink ejection and simultaneously drive the circulation of ink through the circulation channels. This multi-functionality eliminates the need for separate circulation pumping systems, reducing device complexity while maintaining effective ink circulation.
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 design maintains consistent ink ejection quality by preventing viscosity increase and component deposition, reducing production costs through simpler structures and eliminating the need for additional units, thereby enhancing the overall quality of liquid ejection.
Implementation Method 1
a piezoelectric actuator provided on one surface of the channel-forming substrate. In such a recording head, the piezoelectric actuator is deformed to apply pressure to the inside of the pressure-generating chamber, thereby ejecting an ink droplet from a nozzle opening
Data Source
AI summary
A liquid-ejecting head includes a nozzle plate having a nozzle opening that serves for liquid ejection; a channel-forming substrate including pressure-generating chambers that are in communication with the nozzle opening; a pressure generator that serves to generate pressure change in a liquid in the pressure-generating chambers; and a communication plate provided between the nozzle plate and the channel-forming substrate, the communication plate having a communication channel that forms a communication between the pressure-generating chambers and the nozzle opening. The communication plate has a circulation channel that is in communication with a common liquid chamber through the communication channel, the common liquid chamber being in communication with a plurality of the pressure-generating chambers in common.