Inkjet Head Piezoelectric Driver Heat Radiation via Joint Area
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Solution Overview
Problem
The existing ink-jet head designs suffer from uneven discharge characteristics due to varying heat transfer amounts among pressure chambers and piezoelectric elements, leading to inconsistencies in nozzle performance.
Innovation Solution
The design incorporates a channel structure with nozzles and pressure chambers aligned in a specific direction, featuring piezoelectric elements covered by a cover with varying joint regions, where traces from the piezoelectric elements pass through these regions to facilitate enhanced heat radiation, with larger joint areas for effective heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the traces are extended up to outside of the reservoir forming substrate to radiate heat, then heat radiation is improved, but the width of the outer wall portions becomes narrower reducing heat radiation effectiveness
Solution Approach 1:
The patent applies local quality by differentiating the widths of wall portions based on their functional requirements. The first wall portion (outer wall) has a larger width specifically at the first joint region where traces pass through, to enhance heat radiation area. The second wall portion (inner wall) has a smaller width. This localized variation in width optimizes heat radiation where needed while maintaining structural integrity elsewhere.
Solution Approach 2:
The patent addresses the heat radiation problem by transitioning from a two-dimensional trace layout to a three-dimensional structural solution. By making the first wall portion extend further in the width direction and creating a larger first joint region, the patent adds a dimensional aspect to heat dissipation, allowing traces to radiate heat over a larger area without increasing the overall footprint of the device.
2Reliability
If heat is transferred from the driver to the piezoelectric elements via traces, then electrical connection is achieved, but temperature rise causes uneven discharge characteristics
Solution Approach 1:
The patent converts the harmful effect of heat transfer (which causes temperature rise and uneven discharge) into a beneficial effect by designing the first wall portion with larger width and larger first joint region. This structure transforms the heat conduction path into an effective heat radiation pathway, allowing the traces to dissipate heat to the outer environment rather than transferring it to the piezoelectric elements, thereby improving discharge 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 configuration effectively radiates heat away from the driver, reducing temperature differences among nozzles and improving discharge uniformity, thereby stabilizing the discharge characteristics across the ink-jet head.
Implementation Method 1
a portion of the heat is transferred (conducted) to the channel forming substrate via the traces... it is effective to radiate the heat, which is transferred from the driver via the traces, as much as possible
Implementation Method 2
heat is generated in the driver. Since a portion of the heat is transferred (conducted) to the channel forming substrate via the traces
Data Source
AI summary
A liquid discharging apparatus includes: a channel structure having nozzles aligned in a first direction and pressure chambers aligned in the first direction corresponding to the nozzles respectively; piezoelectric elements aligned in the first direction in the channel structure, corresponding to the pressure chambers respectively; a cover covering the piezoelectric elements and having first and second wall portions arranged in a second direction orthogonal to the first direction and joined to the channel structure at first and second joint regions respectively; and traces being extended to one side in the second direction from the piezoelectric elements respectively, passing through the first region, and extending up to outside of the cover. An area of the first joint region is greater than an area of the second region.