Liquid Ejecting Head Inclined Reservoir Bubble Management
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Solution Overview
Problem
Existing liquid ejecting heads face challenges in achieving good ink discharge characteristics due to the absorption of pressure changes by compliance portions, which are affected by the width of the reservoir in a direction perpendicular to the pressure generating chambers, leading to issues with bubble formation and ejection.
Innovation Solution
A liquid ejecting head design featuring a reservoir with an inclined surface that increases the compliance portion's width, allowing for improved pressure absorption and bubble discharge, where the reservoir communicates with the pressure generating chambers in a way that prevents bubbles from staying by facilitating their upward movement through the inclined surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the width of the reservoir in the direction perpendicular to the pressure generating chambers is decreased to prevent bubble accumulation, then bubble generation is reduced, but the compliance portion cannot absorb pressure changes effectively, leading to poor ink discharge characteristic
Solution Approach 1:
The patent introduces a new spatial dimension by tilting the reservoir wall surface at an angle of 45 degrees or more relative to the horizontal direction. This dimensional change allows the compliance portion to maintain sufficient width for pressure absorption while the tilted surface prevents bubble accumulation by directing bubbles toward the discharge direction, thus resolving the contradiction between bubble prevention and pressure absorption.
Solution Approach 2:
The patent creates an asymmetric reservoir structure where the wall surface communicating with pressure generating chambers is tilted at 45 degrees or more, while other portions may have different geometries. This asymmetry allows different regions of the reservoir to perform different functions: the tilted surface prevents bubble accumulation, while the compliance portion maintains adequate width for pressure absorption, resolving the contradiction between these two requirements.
2Reliability
If the width of the compliance portion is increased to improve pressure absorption, then ink discharge characteristic improves, but the reservoir width increases, causing bubbles to stay in the reservoir
Solution Approach 1:
By tilting the reservoir wall surface at 45 degrees or more, the patent utilizes the vertical dimension to prevent bubble accumulation while maintaining adequate horizontal width for pressure absorption. The tilted surface directs bubbles toward the discharge direction without requiring a reduction in compliance portion width, thus resolving the contradiction between pressure absorption and bubble prevention.
Solution Approach 2:
The patent applies different geometric characteristics to different portions of the reservoir: the wall surface communicating with pressure generating chambers is tilted at 45 degrees or more to prevent bubble accumulation, while the compliance portion maintains sufficient width for pressure absorption. This local differentiation resolves the contradiction by allowing each region to optimize for its specific function.
3Object-affected harmful factors
If the reservoir width is decreased to increase liquid flow speed and prevent bubbles, then bubble generation is reduced, but pressure generating chambers cannot obtain good ink discharge characteristic
Solution Approach 1:
The patent resolves this contradiction by introducing a tilted wall surface geometry that operates in a different dimensional approach. Instead of relying solely on reducing reservoir width to increase flow speed, the tilted surface (45 degrees or more) actively directs bubbles toward the discharge direction while maintaining adequate reservoir width for pressure absorption, thus preventing bubble accumulation without compromising ink discharge characteristic.
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 the liquid ejecting characteristic by equalizing the compliances of pressure generating chambers and effectively preventing bubble accumulation, resulting in improved print quality and ejection efficiency.
Implementation Method 1
a compliance portion which absorbs pressure of the reservoir is disposed at an area which faces the lower portion and has a shape corresponding to the lower portion
Implementation Method 2
the reservoir communicates with an upper portion of each of the pressure generating chambers in the vertical direction rather than the lower portion
Implementation Method 3
at least a portion of a wall surface of the reservoir is an inclined surface, a lower side of the reservoir in a vertical direction becomes a lower portion of which a width is wider than an upper side of the reservoir in the vertical direction by the inclined surface
Data Source
AI summary
A liquid ejecting head includes a reservoir forming substrate provided with a reservoir serving as a common liquid chamber; in which at least a portion of a wall surface of the reservoir is an inclined surface, a lower side of the reservoir in a vertical direction is provided with a lower portion of which a width is wider than an upper portion of the reservoir in the vertical direction thanks to the inclined surface, a compliance portion which absorbs pressure of the reservoir is disposed at an area which faces the lower portion and has a shape corresponding to the lower portion, and the reservoir communicates with an upper portion of each of the pressure generating chambers in the vertical direction rather than a lower portion of each of pressure generating chambers.