Ink-jet Head Wiring Substrate High-Density Channel Layout
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Solution Overview
Problem
Conventional ink-jet heads face challenges in achieving high channel density due to wiring electrode corrosion and increased electrical resistance as channel density increases, with existing solutions either exposing electrodes to ink, leading to corrosion, or narrowing wiring electrodes to maintain space, which limits channel density.
Innovation Solution
An ink-jet head design with a wiring substrate attached to the rear face of a harmonica-shaped head chip, where wiring electrodes are formed on the substrate and run between through-holes, avoiding contact with dummy channels and using materials like glass, silicon, or ceramics to maintain rigidity and prevent short-circuits, allowing for high-density channel arrangements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If wiring electrodes are exposed on the back side of the head chip to facilitate electrical connection, then ease of electrical connection is improved, but the wiring electrodes come into contact with ink leading to corrosion and increased electrical resistance
Solution Approach 1:
The patent introduces an insulating film as an intermediary layer between the wiring electrode and the ink. This insulating film prevents direct contact between the conductive wiring electrode and the ink, thereby eliminating corrosion while maintaining the electrical connection functionality. The insulating film acts as a mediator that allows the wiring electrode to remain exposed for connection purposes without suffering from harmful ink contact.
2Productivity
If channel density is increased to achieve high-density arrangements, then productivity is improved, but the space available for wiring electrodes is reduced leading to increased electrical resistance
Solution Approach 1:
The patent resolves the space constraint by transitioning the wiring electrode arrangement to a different dimensional plane. Instead of routing wiring electrodes through the limited lateral space between channels, the wiring electrodes are arranged on the back side of the head chip in a plane that is perpendicular to the ink discharge direction. This dimensional change provides ample space for wiring electrodes even when channel density is high in the lateral direction, thereby maintaining low electrical resistance while achieving high channel density.
3Device complexity
If wiring electrodes are arranged to run between through-holes adjacent to each other, then device complexity is reduced, but the wiring electrodes must be narrowed to fit within the drive wall thickness limiting channel density
Solution Approach 1:
The patent applies dimensional change to resolve the conflict between wiring simplicity and channel density. By moving the wiring electrode arrangement to the back side of the head chip and arranging them in a plane perpendicular to the ink discharge direction, the wiring electrodes can maintain sufficient width for low resistance without interfering with channel spacing. This spatial reconfiguration allows both simple wiring arrangement and high channel density to coexist.
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
Enables high-density channel arrangements without significant increases in electrical resistance, preventing electrode corrosion and allowing for efficient ink discharge even at higher channel densities.
Implementation Method 1
a drive wall made of a piezoelectric element and having shear deformation in a case where a predetermined voltage is applied to a drive electrode formed on a surface of the drive wall facing the inside of the channel
Data Source
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AI summary
The purpose of the present invention is to provide an ink-jet head which enables the disposition of wiring electrodes at high density and can easily support an increased density of channels. An ink-jet head comprises a head chip (1) in which drive channels and dummy channels are alternately disposed, and a wiring substrate (3), and is characterized in that in the wiring substrate (3), through-holes for supplying ink are formed only at positions corresponding to openings of the drive channels, at least one wiring electrode passes between adjacent through-holes in at least one row of through-holes among a plurality of rows of through-holes corresponding to channel rows and extends to an end of the wiring substrate projecting sideways from the head chip, and at least one wiring electrode passing between the through-holes is not in contact with an opening of the dummy channel and overlaps with the opening of the dummy channel as seen from an ink discharge direction.