Liquid Ejection Head Filter Unit Ribs and Inlet Communication
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Solution Overview
Problem
Conventional liquid ejection heads in image forming apparatuses face clogging issues due to impurities and foreign materials in the ink, leading to reduced filtering efficiency and pressure loss, as the filter area is compromised by partition walls in the liquid supply passages.
Innovation Solution
A liquid ejection head design featuring a filter unit with ribs positioned between the inlet portions and the common chamber, allowing for unobstructed filtering across multiple separate chambers, and communication between inlet portions to maintain an adequate filtering area while preventing deformation from pressure fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a filter is disposed at a supply port of the common chamber to remove foreign materials, then filtering effectiveness is improved, but the filter area is reduced when partition walls are present, causing pressure loss and performance reduction
Solution Approach 1:
The patent repositions the filter from the common chamber supply port to the liquid supply passages between the separate chambers and nozzles. This dimensional relocation allows the filter to be distributed across multiple passages, increasing total filter area while avoiding the space constraints of the common chamber. The filter is strategically placed where it can service multiple chambers without being blocked by partition walls.
Solution Approach 2:
The filter is divided into multiple segments, with each separate chamber having its own filter portion within its liquid supply passage. This segmentation allows each filter segment to operate independently, maximizing the effective filtering area across all chambers while preventing clogging from affecting the entire system. Each partition wall now serves as a support structure for filter segments rather than an obstruction.
2Stability of the object's composition
If communicating portions are formed in partition walls to communicate individual liquid-supply passages, then liquid supply stability is improved, but the partition walls shield the filter and narrow the filtering area
Solution Approach 1:
The communicating portions are repositioned from the partition walls to the liquid supply passages, specifically at locations where they can communicate with adjacent passages without intersecting the filter elements. This spatial relocation maintains the liquid supply stability function while eliminating the shielding effect on the filter. The communication paths now run parallel to or alongside the filter rather than through the partition walls that would block the filter.
3Reliability
If the filter is provided for each separate chamber to prevent clogging, then reliability is improved, but the filtering area per chamber is reduced compared to a common filter
Solution Approach 1:
The filtering system is segmented into individual filter portions for each separate chamber, with each filter located within its corresponding liquid supply passage. This segmentation ensures that each chamber receives dedicated filtration, preventing cross-contamination of filtered liquid and ensuring reliable operation. The total filtering area across all chambers is maximized by utilizing the full length of each liquid supply passage for filter placement.
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 configuration enhances the filtering efficiency and maintains stable liquid supply by preventing the filter unit from being shielded by partition walls, reducing pressure loss and ensuring consistent ink ejection performance.
Implementation Method 1
The filter unit is disposed between the plurality of inlet portions and the common chamber to filter liquid
Data Source
AI summary
A liquid ejection head includes nozzles, separate chambers, a common chamber, inlet portions, a filter unit, and ribs. Droplets of liquid are ejected from the nozzles. The separate chambers are communicated with the nozzles. The inlet portions are communicated with the corresponding separate chambers. Liquid is supplied from the common chamber to the separate chambers through the inlet portions. The filter unit is disposed between the inlet portions and the common chamber to filter liquid in an area across the separate chambers in a first direction in which the nozzles are arrayed. The ribs are disposed in the filter unit at intervals corresponding in size to at least two of the separate chambers in the first direction to partition the filter unit. The inlet portions are communicated in the first direction with each other in at least one portion of each of the inlet portions facing the filter unit.