Liquid Ejection Head Filter Upward Flow Bubble Management
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Solution Overview
Problem
Page wide type liquid ejection heads with circulation systems face issues with foreign objects and minute bubbles accumulating in filters, leading to adverse effects on liquid flow, particularly due to the large volume of liquid required and increased catchment of debris, which can cause filter clogging and instability in the flow.
Innovation Solution
A page wide type liquid ejection head with a circulation system that includes a buffer tank for bubble discharge, positive displacement pumps for constant flow rate management, and a filter arrangement where liquid flows from downward to upward through the filter, allowing foreign objects to accumulate at the bottom and minute bubbles to be diffused, ensuring stable liquid flow even with increased debris.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a circulation system is used to supply large volume of liquid to the page wide type head, then the recording speed and productivity are improved, but foreign objects and minute bubbles accumulate in the filter causing clogging and flow instability
Solution Approach 1:
The filter chamber is divided into a first chamber (below the filter) and a second chamber (above the filter), with separate inlet and outlet ports. This segmentation allows liquid to flow through the filter from bottom to top while enabling independent control of bubble discharge, preventing bubble accumulation on the filter surface and maintaining stable flow conditions during high-speed recording operations.
Solution Approach 2:
The invention extracts and removes minute bubbles from the liquid flow by providing a dedicated bubble discharge outlet in the second chamber above the filter. This allows bubbles to be separated and discharged from the liquid stream, preventing them from accumulating on the filter surface and causing clogging, thereby maintaining filter flow stability during high-speed operation.
2Reliability
If the filter is arranged to catch foreign objects and minute bubbles, then ejection port clogging is prevented, but the filter surface becomes covered by accumulated bubbles and foreign objects adversely affecting liquid flow
Solution Approach 1:
The filter system performs self-cleaning by allowing liquid to continuously flow through it from the first chamber below to the second chamber above. Foreign objects and minute bubbles are automatically carried away by the flowing liquid and discharged through the outlet port, eliminating the need for manual cleaning and maintaining ejection port functionality without increasing maintenance complexity.
Solution Approach 2:
Instead of the conventional top-to-bottom filter arrangement where bubbles accumulate on the filter surface, the invention inverts the flow direction to bottom-to-top. This causes bubbles and foreign objects to be carried upward and discharged through the outlet in the second chamber, preventing filter surface coverage and maintaining reliable ejection port functionality.
3Reliability
If a vertically arranged filter with exhaust path is used to discharge bubbles, then bubble accumulation is suppressed, but foreign objects accumulate on the filter and adversely affect liquid flow
Solution Approach 1:
The filter structure serves multiple functions simultaneously: it filters foreign objects from the liquid, allows continuous bubble discharge through the second chamber outlet, and maintains stable liquid flow. The single integrated filter chamber design with divided spaces performs all these functions without requiring additional separate components, avoiding increased structural 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
The solution effectively suppresses the adverse effects of foreign objects and minute bubbles on the filter, maintaining stable liquid flow and image quality during high-speed recording operations by ensuring the filter is not clogged and the liquid flow remains uninterrupted.
Implementation Method 1
liquid flows from downward to upward through the filter, allowing foreign objects to accumulate at the bottom
Implementation Method 2
minute bubbles to be diffused
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Element substrate 2 has ejection ports for ejecting liquid, pressure chambers 62 for storing the liquid to be ejected from the ejection ports, liquid supply paths for supplying liquid to the pressure chambers and liquid recovery paths 66 for recovering liquid from the pressure chambers. The filter chambers 23 have respective filters 11 for seizing foreign objects contained in liquid. Liquid is forced to flow from downward to upward relative to the filters 11.