Inkjet Head Reference Potential via Insulated Metal Joint
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Solution Overview
Problem
Existing inkjet heads face challenges in maintaining a uniform potential, leading to potential disruptions in the drive circuit due to charge release from non-electrode portions, especially when insulating filters are used between the reservoir and flow-path units.
Innovation Solution
The inkjet head design includes a flow-path unit, a reservoir unit, and an actuator unit, where the metal portions of the flow-path and reservoir units are electrically connected through an insulating material layer, allowing the second electrode of the actuator unit to connect with the metal portion of the flow-path unit, ensuring the entire system remains at a reference potential, even with insulating materials in between, thus eliminating the need for additional conductive members.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If an insulating material layer (filter) is interposed between the reservoir unit and flow-path unit, then dust filtering is improved, but electrical connection between metal portions is lost
Solution Approach 1:
The patent introduces a conductive member as an intermediary element that bridges the electrical connection across the insulating filter material. The conductive member penetrates or contacts both metal portions on either side of the filter, enabling charge dissipation while the filter continues to block dust particles. This mediator resolves the contradiction by providing a dedicated electrical pathway that does not interfere with the filter's physical barrier function.
2Strength
If metal plates are stacked to form flow-path and reservoir units, then structural strength is improved, but charge accumulation and circuit breakdown risk increase
Solution Approach 1:
The patent extracts the charge dissipation function from the structural metal plates by introducing a dedicated conductive member. The metal plates maintain their structural role while the conductive member specifically handles the electrical charge management. This separation of functions allows the metal structure to provide strength without accumulating harmful charges that could damage drive circuits.
3Reliability
If the inkjet head is kept at reference potential through direct metal connection, then circuit protection is improved, but manufacturing complexity increases due to additional conductive members
Solution Approach 1:
The conductive member is designed to serve multiple functions simultaneously: it provides electrical connection for charge dissipation, maintains mechanical alignment between stacked components, and may serve as a grounding path. By making the conductive member multi-functional, the patent reduces the need for separate dedicated components, thereby simplifying the overall structure while maintaining circuit protection.
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 ensures reliable electrical connection and maintains the inkjet head at a consistent potential, preventing circuit disruptions and reducing manufacturing costs by simplifying the electric connection structure.
Implementation Method 1
The actuator unit includes a plurality of piezoelectric sheets, a plurality of first electrodes and a second electrode... when the drive voltage is applied from a drive circuit to the first electrodes of the actuator unit, the volume of the pressure chambers corresponding to the first electrodes varies to apply pressure to the ink in the pressure chambers, to thereby eject the ink from the nozzles
Data Source
AI summary
An inkjet head includes a flow-path unit, a reservoir unit and an actuator unit. The flow-path unit includes a common ink chamber and plural individual ink flow paths. The actuator unit includes plural first electrodes and a second electrode. The first electrodes are arranged to correspond to pressure chambers, respectively. The first electrodes are fed selectively with respective drive voltages for varying a volume of the pressure chambers. One of the flow-path unit and the reservoir unit includes a first metal portion, and the other includes a second metal portion. The metal portion of the flow-path unit and the second electrode are electrically connected with each other. The first metal portion and the second metal portion are jointed to each other through an insulating material layer. An electric connection portion, which is in direct contact with the second metal portion, is integrated with the first metal portion.