Insulating Liquid Ejecting Head Electrode Inspection
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Solution Overview
Problem
Ink jet printing heads with nozzle plates made of insulating materials pose challenges in detecting breakages in the vibration plate during manufacturing, as existing inspection methods relying on conductive states are not effective for non-conductive materials.
Innovation Solution
A liquid ejecting head design featuring a nozzle plate and passage forming boards made of insulating materials, with first and second electrode layers disposed on the vibration plate and extending outside the junction of the passage forming boards, allowing for the detection of a conductive state between these electrodes when the liquid passage is filled, facilitating the identification of breakages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the nozzle plate is formed of an insulating material, then the manufacturing precision and reliability are improved, but the ease of detecting breakage in the vibration plate deteriorates
Solution Approach 1:
The patent introduces electrode layers as intermediary elements that enable detection of vibration plate breakage. These electrodes are disposed on the vibration plate and extend outside the junction portion of the passage forming boards, allowing electrical contact through the liquid in the liquid passage to detect breakages even when the nozzle plate is made of insulating material.
Solution Approach 2:
The patent replaces mechanical detection methods with electrical detection. Instead of using mechanical means to detect breakage, the invention uses electrical conductivity through the liquid medium to detect breakages in the vibration plate, enabling inspection without requiring the nozzle plate to be conductive.
2Ease of manufacture
If the nozzle plate is formed of a conductive material, then the ease of inspecting for vibration plate breakage is improved, but the manufacturing precision deteriorates
Solution Approach 1:
The electrode layers serve as intermediaries that enable electrical inspection without requiring the nozzle plate itself to be conductive. The electrodes are positioned on the vibration plate and extend beyond the junction portion, allowing electrical contact through the liquid to detect breakages while the nozzle plate can be made of insulating material for manufacturing precision.
3Device complexity
If the electrode layers are disposed inside the junction portion, then the device complexity is reduced, but the ease of operation deteriorates
Solution Approach 1:
The electrode layers are segmented into two independent layers (first and second electrode layers) that are disposed on opposite sides of the vibration plate. This segmentation allows electrical inspection by detecting the conductive state between the two electrodes through the liquid, enabling easy operation while maintaining reasonable device complexity.
Solution Approach 2:
The electrode layers are extended to a different spatial dimension by disposing them outside the junction portion of the passage forming boards. This dimensional extension allows external electrical contact and simplifies the inspection operation without significantly increasing device complexity.
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 enables easy and reliable detection of breakages in the vibration plate, reducing initial failure rates and ensuring the production of high-quality products by determining the conductive state between the electrode layers.
Implementation Method 1
a first electrode layer electrically connected to the liquid storing the first liquid passage and a second electrode layer independent from the first electrode layer are disposed on the vibration plate
Data Source
AI summary
A liquid ejecting head ejects a liquid from pressure generating chambers through nozzles by varying pressure of the pressure generating chambers. The liquid ejecting head includes a nozzle plate in which the nozzles are formed. A first passage forming board is joined to the nozzle plate. A first liquid passage, including the pressure generating chambers, is formed in the first passage forming board. A second passage forming board is joined to the surface of the first liquid passage forming board and has a second liquid passage communicating with the first liquid passage. A first electrode layer electrically connected to the liquid in the first liquid passage and a second, independent, electrode layer are disposed on a vibration plate. Each of the first and second electrode layers includes a terminal drawn to the outside of a junction portion joining the first and second passage forming boards to each other.