Bubble Tolerant Manifold Design for Liquid Ejecting Heads
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Solution Overview
Problem
Inkjet heads face issues where bubbles formed in the manifold can block liquid supply channels, leading to incomplete ejection through nozzles, as bubbles move and cover other channels, causing air buildup and insufficient pressure for ink ejection.
Innovation Solution
The design incorporates depressions in the liquid supply channels' openings within the manifold, which trap bubbles, preventing them from moving to other channels and ensuring continuous ink ejection across multiple nozzles by using partitions between adjacent supply openings to block bubble movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If bubbles are allowed to move freely in the manifold, then they can be transported along with liquid flow, but they will cover liquid supply channel inlets and block liquid flow to multiple nozzles
Solution Approach 1:
The invention divides the manifold into multiple independent regions, each serving a specific nozzle. By segmenting the liquid supply paths and assigning dedicated bubbles to specific nozzles, the system prevents bubbles from migrating between channels and blocking multiple nozzles simultaneously, thus maintaining reliable liquid ejection across all nozzles
Solution Approach 2:
The invention introduces an intermediary structure (such as a partition wall or directional flow design) between the manifold and liquid supply channels. This intermediary element controls bubble movement, allowing bubbles to be present in the manifold while preventing them from entering and blocking the liquid supply channel inlets, thereby resolving the conflict between bubble transport and flow blockage prevention
2Stress or pressure
If pressure generating elements continue driving when liquid flow is cut off, then pressure can be maintained in pressure generating chambers, but air builds up and prevents sufficient pressure generation for liquid ejection
Solution Approach 1:
The invention implements a feedback mechanism where the system monitors liquid flow conditions in real-time. When bubble blockage is detected and liquid flow is cut off, the feedback signal triggers the pressure generating elements to stop driving, preventing air buildup that would compromise pressure generation capability and liquid ejection function
Solution Approach 2:
The invention takes preliminary action by detecting bubble presence and potential blockage before complete flow cutoff occurs. By preemptively stopping the pressure generating elements when bubbles are detected approaching the liquid supply channels, the system prevents air buildup and maintains pressure generation readiness, ensuring reliable liquid ejection can resume when bubbles are cleared
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 effectively prevents the simultaneous failure of multiple nozzles due to bubble blockage, maintaining consistent ink ejection and improving printing quality by containing bubbles within depressions, thus maintaining pressure and flow.
Implementation Method 1
The liquid supply opening of at least one of the liquid supply channels is located in the inner surface of a depression that has an opening that opens into the manifold
Data Source
AI summary
A liquid ejecting head includes pressure generating chambers; nozzles that communicate with respective pressure generating chambers; a manifold that communicates with a liquid introduction opening and that serves as a common flow channel for the multiple pressure generating chambers; liquid supply channels, having liquid supply openings that open into the manifold, that communicate between the manifold and the pressure generating chambers; and a pressure generating element that causes liquid to be ejected through the nozzles by generating pressure within the pressure generating chambers. At least one of the liquid supply openings is physically separated from at least one adjacent liquid supply opening, such as by a partition, which prevents air bubbles from moving between adjacent liquid supply openings.