Inkjet Head Shear Deformation Uniformization via Perpendicular Substrate Access
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Solution Overview
Problem
Inkjet heads with harmonica type head chips face challenges in achieving uniform speed distribution across nozzles due to non-uniform channel characteristics, leading to dispersion in ink landing accuracy and image quality, and existing methods to adjust driving electrodes are hindered by substrate obstructions and complexity.
Innovation Solution
The design involves a piezoelectric element-based driving wall with alternate channels, where a connection electrode is formed on the rear surface of the head chip, allowing a wiring substrate with an opening to be connected perpendicularly, enabling easy adjustment of shear deformation to uniformize inkjet characteristics by measuring and adjusting ink particle velocity, volume, or diameter distributions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a harmonica type head chip is used to improve productivity, then manufacturing efficiency increases, but adjusting driving electrodes becomes difficult due to substrate obstructions
Solution Approach 1:
The patent applies dimensionality change by providing openings in the substrate that expose the rear surface of the head chip, allowing access to driving electrodes from a different spatial dimension (through the substrate thickness). This enables adjustment operations without requiring disassembly or complex access routes, resolving the contradiction between maintaining compact harmonica structure and enabling electrode adjustment.
2Device complexity
If a single power source is used to apply voltage to each channel, then device complexity is reduced, but speed distribution uniformity deteriorates
Solution Approach 1:
The patent applies local quality by providing individual adjustment mechanisms (such as trimming electrodes or adding adjustment electrodes) for each driving electrode while maintaining a single common power source. This allows local modification of electrical characteristics for each channel to compensate for non-uniformities, achieving uniform speed distribution without requiring separate power sources for each channel.
3Manufacturing precision
If driving electrodes are adjusted to uniformize speed distribution, then inkjet performance uniformity improves, but production complexity and cost increase
Solution Approach 1:
The patent applies preliminary action by incorporating adjustment electrodes or trimming structures during the initial manufacturing process of the head chip, before final assembly. This allows speed distribution uniformity to be established during production rather than requiring complex post-assembly adjustments, reducing both production complexity and cost while achieving the desired uniformity.
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 approach allows for efficient uniformization of channel characteristics, reducing the complexity and cost of adjusting driving electrodes, thereby enhancing image quality by ensuring consistent inkjet performance across all nozzles.
Implementation Method 1
voltage is applied to the driving electrode to cause shear-deformation of the driving wall
Implementation Method 2
a driving wall made of a piezoelectric element
Data Source
AI summary
An inkjet head has a head chip. The head chip has driving walls of piezoelectric material, which deform by applying voltage, to jet ink. Channels are arranged alternatively, alongside the driving walls and contain ink. Each channel has an outlet and an inlet port at a front and rear surface of the head chip. Driving electrodes, formed on surfaces of the driving walls, apply voltage to the driving walls. Connection electrodes, formed on the rear surface of the head chip, electrically connect to the driving electrodes. A wiring substrate, having wiring electrodes apply voltage to the driving electrode through the connection electrode. The wiring substrate is bonded to the rear surface of the head chip to protrude from the head chip in a direction perpendicular to the direction of the channels so that all the channels are exposed at the rear surface of the head chip.