Liquid Ejection Head Unit Thermal Isolation via Flexible Circuit
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Solution Overview
Problem
Existing liquid ejection apparatuses, such as ink jet printers, face challenges in improving ink ejection accuracy and reducing the adverse effects of heat generated by drive signal output circuits on ink ejection characteristics, as the drive signal propagation path is often lengthy, leading to inefficient ink ejection and potential thermal interference with the ejection head.
Innovation Solution
The liquid ejection apparatus incorporates a head unit with a drive signal output circuit positioned away from the ejection head, utilizing a wiring substrate to minimize heat transfer, and includes a drive signal selection circuit that generates optimized drive signals to control the ejection of ink based on image data, ensuring precise ink droplet formation and reduced thermal impact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the drive signal output circuit is installed in the vicinity of the liquid ejection head to shorten the propagation path, then ink ejection accuracy is improved, but heat generated in the drive signal output circuit is transferred to the liquid ejection head and affects ejection characteristics
Solution Approach 1:
The apparatus is divided into separate functional modules: the drive signal output circuit is housed in a drive unit, while the liquid ejection head is a separate ejection unit. This segmentation allows the heat-generating drive circuit to be physically isolated from the temperature-sensitive ejection head, resolving the contradiction between shortening signal paths and reducing heat transfer.
Solution Approach 2:
A flexible printed circuit board (FPC) is introduced as an intermediary component to connect the drive unit and ejection unit. The FPC transmits drive signals over a longer distance without significant signal degradation while simultaneously acting as a thermal barrier that prevents heat from the drive circuit from reaching the ejection head.
2Object-affected harmful factors
If the drive signal propagation path is lengthened to separate the drive circuit from the ejection head, then heat transfer to the ejection head is reduced, but ink ejection accuracy deteriorates due to longer signal paths
Solution Approach 1:
The flexible printed circuit board serves as an intermediary that enables long-distance signal transmission while maintaining signal integrity. Its flexible nature allows for optimized routing that minimizes electrical interference and signal degradation, thus preserving ejection accuracy despite the increased physical separation between drive circuit and ejection head.
Solution Approach 2:
The patent replaces rigid circuit board connections with a flexible printed circuit board that can be precisely routed and positioned. This substitution allows for optimized signal paths that account for both electrical performance and thermal isolation requirements, enabling the system to achieve both long separation distance and high ejection accuracy.
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 enhances ink ejection accuracy and reduces the influence of heat from the drive signal output circuit on the ejection head, resulting in improved ink ejection characteristics and more precise image formation on the medium.
Implementation Method 1
a piezoelectric element such as a piezo element is used... by driving each of the piezoelectric elements in accordance with the drive signal
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
A liquid ejection apparatus includes a head unit that ejects a liquid, and a control unit that controls an operation of the head unit, wherein the head unit includes a drive signal output circuit that outputs a drive signal, a first substrate on which the drive signal output circuit is provided, and a first ejection head including a first drive element driven by the drive signal, and a first nozzle plate including a first nozzle from which a liquid is ejected by driving the first drive element, wherein the first substrate includes a first face and a second face, wherein the drive signal output circuit is provided on the first face, and wherein a shortest distance between the first nozzle plate and the second face is shorter than a shortest distance between the first nozzle plate and the first face.