Liquid Ejecting Head Overhang Seal Plate Bubble Discharge
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Solution Overview
Problem
Existing liquid ejecting heads face issues with air bubble accumulation and reduced pressure change absorption due to angular intersections between the inner peripheral surface of the opening and the sealing film, leading to stagnation and decreased efficiency in ink discharge.
Innovation Solution
The implementation of a liquid ejecting head design featuring a flexible seal plate with an overhang portion having an inclined surface that overhangs from the inner peripheral surface of the opening, preventing stagnation and ensuring a sufficient opening area for effective pressure change absorption and improved air bubble discharge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the opening is sealed with a sealing film to prevent pressure change propagation, then pressure isolation between chambers is improved, but air bubbles accumulate at the angular intersection and liquid stagnation occurs
Solution Approach 1:
The patent applies curvature by forming a rounded corner at the intersection between the sealing film and the opening instead of a sharp angular shape. This curved transition eliminates stagnant liquid zones and prevents air bubble accumulation while maintaining the sealing function that isolates pressure changes between chambers.
2Object-generated harmful factors
If the opening area is reduced to prevent liquid stagnation, then air bubble discharge is improved, but the absorption effect on pressure change by the seal plate decreases
Solution Approach 1:
The rounded corner design allows the opening to maintain a sufficient area while preventing liquid stagnation. The curved geometry guides liquid flow smoothly without requiring excessive area reduction, thus preserving the seal plate's ability to absorb pressure changes effectively.
3Ease of manufacture
If a sharp angular shape is used at the opening-sealing film intersection, then manufacturing is simpler, but liquid stagnation and air bubble accumulation occur
Solution Approach 1:
The rounded corner configuration balances manufacturing feasibility with improved liquid flow characteristics. The curved geometry is straightforward to manufacture using conventional techniques while simultaneously eliminating stagnant zones and enhancing air bubble discharge efficiency.
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 discharge of air bubbles while maintaining the absorption effect on pressure changes, ensuring efficient ink flow and preventing a decrease in the absorption effect on pressure changes by the seal plate.
Implementation Method 1
a flexible sealing film (also referred to as a compliance substrate) is disposed on the opening of the reservoir. In this configuration, a fine pressure change in the reservoir is absorbed by the sealing film so that a pressure change in each pressure chamber does not effect on other pressure chambers via the reservoir
Implementation Method 2
the overhang portion having the inclined surface which overhangs from the inner peripheral surface of the opening is disposed on an end of the opening. Accordingly, at the end of the opening where air bubbles are likely to be accumulated, a flow is formed along the inclined surface of the overhang portion
Data Source
AI summary
A liquid ejecting head includes a head main body in which a nozzle N that ejects liquid is formed; a case member which includes a space that stores liquid to be supplied to the nozzle and an opening that communicates with the space; a flexible seal plate that closes the opening from an outside of the case member; and an overhang portion disposed on an end of the opening and having an inclined surface that overhangs from an inner peripheral surface of the opening.