Offset Nozzle Rows with Overlapping Filter Chambers for Pressure Uniformity
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Solution Overview
Problem
In liquid ejecting heads, such as ink jet type recording heads, elongating the nozzle row or increasing nozzle density is challenging due to yield deterioration and increased manufacturing costs, and existing designs face issues with pressure loss variations and discharge characteristics across nozzle rows, affecting print quality.
Innovation Solution
A liquid ejecting head design featuring offset nozzle rows with a shared supply flow path and overlapping filter chambers, where the supply path branches between the filter chambers at a specific position, ensuring even pressure distribution and reduced pressure loss variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If multiple head chips are fixed to a common flow path member to elongate the nozzle row, then the nozzle row length increases, but pressure loss variation occurs between nozzle rows due to different flow path lengths from the introduction port to each filter chamber
Solution Approach 1:
The patent transitions from a linear arrangement of filter chambers to a three-dimensional overlapping configuration where filter chambers are positioned both in the extending direction and in an overlapping direction. This spatial reorganization allows the branch position to be located between filter chambers in plan view while maintaining compact overall dimensions, thereby equalizing flow path lengths to multiple nozzle rows simultaneously.
Solution Approach 2:
The patent positions the branch position specifically between filter chambers in plan view, creating a localized structural feature that optimizes flow distribution. This localized branching configuration ensures that each nozzle row receives liquid with minimized pressure loss variation, addressing the uniformity issue at the critical flow distribution point.
2Productivity
If head chips are disposed offset from each other to increase nozzle density, then the number of nozzles per unit length increases, but variation in discharge characteristics occurs due to unequal flow path lengths
Solution Approach 1:
The patent utilizes both the extending direction and the overlapping direction to position filter chambers, creating a two-dimensional layout that serves multiple nozzle rows. This multi-dimensional arrangement allows offset positioning of head chips to achieve high nozzle density while the branch position between filter chambers in plan view ensures equal flow path lengths, maintaining uniform discharge characteristics.
Solution Approach 2:
The patent creates equipotential flow conditions by positioning the branch position between filter chambers in plan view, ensuring that the liquid pressure and flow path length are equalized for multiple nozzle rows. This equipotential design eliminates pressure loss variation and ensures uniform discharge characteristics across all nozzles, even when head chips are offset to increase density.
3Device complexity
If filter chambers are positioned sequentially along the flow path, then the structure is simple, but the flow path length to each nozzle row becomes unequal causing pressure loss variation
Solution Approach 1:
The patent merges the functions of multiple filter chambers by positioning them to overlap in the extending direction while placing the branch position between them in plan view. This merged configuration allows a single branch position to serve multiple filter chambers and nozzle rows simultaneously, equalizing flow path lengths without requiring separate branching points for each chamber, thus maintaining structural simplicity while achieving pressure uniformity.
Solution Approach 2:
The patent resolves the contradiction by utilizing the overlapping direction as an additional dimension for filter chamber positioning. Filter chambers are arranged to overlap in the extending direction but are positioned such that the branch position lies between them in plan view. This three-dimensional arrangement equalizes flow path lengths to multiple nozzle rows while keeping the overall structure compact and relatively simple.
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 enhances print quality by minimizing pressure loss variations and improving discharge characteristics across nozzle rows, allowing for more efficient ink distribution and reduced manufacturing costs.
Implementation Method 1
ensuring even pressure distribution and reduced pressure loss variations
Data Source
AI summary
There is provided a liquid ejecting head including: first and second nozzle rows extending in a first direction; a first supply flow path; a first filter chamber having a first inlet; and a second filter chamber having a second inlet, in which the first and second nozzle rows are shifted from each other in both the first direction and a second direction orthogonal to the first direction, the first supply flow path has a branch flow path for distributing the liquid between the first filter chamber and the second filter chamber at a branch position, the branch position is disposed between the first filter chamber and the second filter chamber in a plan view, and the first and second inlets are disposed at a part where the first filter chamber and the second filter chamber overlap each other when viewed in the second direction.