Liquid Ejecting Head Acute Angle Steps Adhesive Control
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Solution Overview
Problem
The adhesive used in liquid ejecting heads tends to move to the active portion of the pressure chamber due to capillary forces during bonding, leading to variations in ink ejection characteristics, which existing solutions like steps on the side wall of the pressure chamber fail to adequately prevent.
Innovation Solution
The implementation of multiple steps on the inner wall surface of the flow path reaching the communication hole and the formation of acute angle portions with intersecting partition walls, along with a second step in the communication portion between the pressure chamber and the communication hole, inhibit adhesive movement to the active portion, preventing curing and maintaining consistent ink ejection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single step is disposed on the side wall of the pressure chamber to suppress adhesive movement, then adhesive movement along the acute angle portion is partially prevented, but adhesive can still move to the active portion through the communication hole, causing ejection characteristic variations
Solution Approach 1:
The flow path is divided into multiple segments by disposing at least two steps at different positions (one in the pressure chamber and another in the communication hole or communication portion). This segmentation creates multiple barriers that progressively block adhesive movement, preventing it from reaching the active portion while maintaining structural feasibility.
Solution Approach 2:
The steps are disposed at different positions along the flow path, creating a multi-level barrier structure. By placing steps at different locations (pressure chamber side and communication hole side), the solution addresses adhesive movement from multiple spatial dimensions, ensuring comprehensive blocking without requiring excessive complexity in a single location.
2Reliability
If the communication hole is formed to communicate with the acute angle portion of the pressure chamber, then adhesive can be suppressed from reaching the active portion, but liquid ejection may be inhibited due to adhesive proximity to the communication hole
Solution Approach 1:
A step structure is introduced as an intermediary element between the acute angle portion and the active portion. This intermediate barrier allows the communication hole to maintain its position for effective adhesive suppression while preventing direct adhesive contact with the active portion, thus preserving liquid ejection functionality.
Solution Approach 2:
The step structure creates localized barriers at specific positions along the flow path. By concentrating the blocking function at strategic locations (at the pressure chamber side and at the communication hole side), the solution achieves effective adhesive suppression without affecting the overall liquid ejection performance in other regions.
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 effectively suppresses adhesive movement to the active portion, thereby stabilizing ink ejection characteristics and preventing variations in droplet amount and speed.
Implementation Method 1
A phenomenon of the adhesive moving to the upper side (side opposite to the nozzle plate 94) due to a capillary force when the substrates are bonded via the adhesive was confirmed in the recording head described above
Data Source
AI summary
A liquid ejecting head includes a pressure chamber substrate formed of silicon where a pressure chamber is formed, and a communication plate penetrated by communication holes in a plate thickness direction, in which the pressure chamber partitioned by partition walls formed of crystal orientation planes being formed in the recording head through etching. Acute angle portions are formed, by the partition walls intersecting with each other at an acute angle, in both end portions of the pressure chamber in a first direction, and a first step is disposed in the middle of each of the acute angle portions in an etching direction. Parts of the communication holes are arranged at positions superimposed on the acute angle portions in a bonding surface and remaining parts of the communication holes are arranged on outer sides in the first direction with respect to the acute angle portions such that a second step is formed in a communication portion between the pressure chamber and the communication holes.