Liquid Jetting Apparatus Adhesive Thickness Control
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Solution Overview
Problem
In ink-jet heads, the pressing force applied during the adherence of the supply member can damage the piezoelectric elements due to the accumulation of production errors, causing the protective member's height to exceed designed dimensions and exerting excessive force on the piezoelectric elements and associated thin films.
Innovation Solution
A liquid jetting apparatus design where the thickness of the first adhesive between the protective member and the supply member is different from the thickness of the second adhesive between the flow passage member and the supply member, with the first adhesive being thicker to distribute the pressing force more evenly, thereby reducing the pressure on the piezoelectric elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the supply member is joined to both the communication plate and the protective member, then the adhesion strength is improved, but the pressing force damages the piezoelectric elements
Solution Approach 1:
A recess portion is formed in the protective member at the position corresponding to the piezoelectric element, and a cushioning member is provided in this recess portion. The cushioning member has a pressing force receiving surface that faces the supply member, and it elastically deforms to absorb the pressing force applied during adhesion, thereby protecting the piezoelectric element from damage while maintaining strong adhesion between the supply member and both the protective member and communication plate
2Area of stationary object
If the protective member height increases due to accumulated tolerances, then the adhesion area is improved, but the piezoelectric element is damaged by excessive pressure
Solution Approach 1:
The recess portion is formed in advance in the protective member to accommodate the cushioning member, which is designed to elastically deform and absorb excessive pressing force. This allows the protective member to have sufficient height for adhesion while the cushioning member prevents the piezoelectric element from being damaged by excessive pressure during the adhesion process
3Strength
If the supply member is pressed against the protective member, then the adhesion is strengthened, but the thin films are damaged
Solution Approach 1:
The cushioning member is pre-installed in the recess portion of the protective member to elastically deform and absorb the pressing force applied during adhesion. This cushioning action protects the thin films associated with the piezoelectric element from damage while allowing the supply member to adhere strongly to both the protective member and communication plate
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 minimizes the risk of damaging the piezoelectric elements by distributing the pressing force more evenly, preventing damage from excessive pressure and allowing for the miniaturization of the head unit while maintaining reliable adhesion.
Implementation Method 1
a piezoelectric element provided on the flow passage member to overlap with the pressure chamber
Data Source
AI summary
A liquid jetting apparatus comprises a flow passage member which has a pressure chamber communicated with a nozzle and a liquid supply port communicated with the pressure chamber; a piezoelectric element with which the flow passage member is provided so that the piezoelectric element is overlapped with the pressure chamber; a protective member which is arranged on the flow passage member so that the piezoelectric element is covered therewith; and a supply member which is formed with a supply flow passage communicated with the liquid supply port of the flow passage member and which is adhered to extend over the flow passage member and the protective member; wherein a layer of a first adhesive to adhere the protective member and the supply member is thicker than a layer of a second adhesive to adhere the flow passage member and the supply member.