Ink-jet Head Spacer Design for Actuator Clearance
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Solution Overview
Problem
The existing ink-jet head designs face issues where the flexible cable comes into contact with the actuator unit due to heat treatment or warpage, hindering the deformation of the actuator unit and affecting ink ejection efficiency.
Innovation Solution
The introduction of spacers between the actuator unit and the flexible cable, which are not electrically connected, supports the flexible cable and maintains a clearance from the actuator unit, preventing contact and ensuring proper deformation and ink ejection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the flexible cable is bonded to the actuator unit using heat treatment, then electrical connection is achieved, but the flexible cable deforms downward and contacts the piezoelectric sheet, hindering actuator deformation
Solution Approach 1:
A land is introduced as an intermediary component between the flexible cable and the piezoelectric sheet. The land has a larger thickness than the individual electrode and serves as a mediator that prevents the flexible cable from directly contacting the piezoelectric sheet while maintaining electrical connection through the land.
Solution Approach 2:
The land is pre-formed on the piezoelectric sheet in regions corresponding to no pressure chamber before bonding the flexible cable. This preliminary structure ensures that when heat treatment is applied for bonding, the flexible cable is guided to contact the land rather than the piezoelectric sheet, preventing harmful contact.
2Object-affected harmful factors
If the flexible cable is kept spaced apart from the actuator unit, then actuator deformation is prevented, but electrical connection between individual electrodes and wirings becomes difficult
Solution Approach 1:
The land acts as a mediator that enables electrical connection while maintaining spatial separation. It provides a contact surface for the flexible cable wiring that is electrically connected to the individual electrode, allowing the cable to be spaced apart from the actuator unit's sensitive regions.
Solution Approach 2:
The land is selectively provided only in regions of the piezoelectric sheet that correspond to no pressure chamber, creating local variations in thickness and electrical connectivity. This local quality allows electrical connection in specific areas while maintaining clearance in other areas to prevent contact with the actuator unit.
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 deformation of the flexible cable towards the actuator unit, preventing contact and ensuring unhindered deformation of the actuator unit, thereby enhancing ink ejection efficiency and reliability.
Implementation Method 1
Driving of the actuator unit causes the piezoelectric sheets to exhibit unimorph deformation by a transversal piezoelectric effect
Data Source
AI summary
An ink-jet head includes a passage unit, an actuator unit, a flexible cable, conductors, and spacers. The actuator unit has individual electrodes corresponding to respective pressure chambers of the passage unit. The flexible cable has wirings corresponding to the respective individual electrodes and is spaced apart from the actuator unit. The conductors are disposed between the actuator unit and the flexible cable so as to electrically connect the individual electrodes to the wirings, respectively. The spacers, which are not electrically connected to the individual electrodes and the wirings, are disposed between the actuator unit and the flexible cable so that each of the spacers is positioned in a region surrounded by three or more of the conductors.