Liquid Ejecting Apparatus Cooling Unit with Adaptive Heat Circulation
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Solution Overview
Problem
Existing liquid ejecting apparatuses face challenges in maintaining high ejection stability due to increased inductance from long wiring distances and inefficient cooling mechanisms that can lead to overheating of drive circuits and potential short-circuiting from ink mist, especially when air or water cooling is used.
Innovation Solution
A cooling unit with thermal conductive members and a controller that dynamically adjusts the circulation of liquid through these members based on the heat generation of different portions of the drive circuit, ensuring efficient heat dissipation by prioritizing cooling where it is needed most.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the drive circuit is disposed just above the head to reduce wiring distance, then ejection stability is improved, but the temperature of the drive circuit becomes very high
Solution Approach 1:
The drive circuit is divided into multiple portions (first portion and second portion), and each portion is cooled independently by separate thermal conductive members. This segmentation allows targeted cooling of specific high-heat-generation areas without requiring a single large cooling structure, thus managing temperature while maintaining the compact layout for ejection stability.
Solution Approach 2:
Different thermal conductive members are applied to different portions of the drive circuit based on their heat generation characteristics. The controller dynamically adjusts which portions receive cooling based on real-time heat generation patterns, providing localized cooling where needed rather than uniform cooling across the entire drive circuit.
2Temperature
If air cooling is performed just above the head, then cooling is provided, but it has an influence on the position where ink droplet lands and ink mist may attach to electronic parts causing short-circuiting
Solution Approach 1:
Thermal conductive members are introduced as intermediary elements between the drive circuit and the cooling liquid. These members conduct heat away from the drive circuit internally through thermal conduction, eliminating the need for direct air cooling above the head that would interfere with ink droplet placement and risk ink mist attachment to electronic parts.
3Temperature
If electronic parts are disposed in descending order of heat generation from upstream side on flow passage, then cooling is provided, but cooling efficiency will be low depending on image data to be printed
Solution Approach 1:
The cooling system transitions from a static fixed-order cooling approach to a dynamic adaptive cooling approach. The controller dynamically determines the cooling sequence based on real-time detection of heat generation in different drive circuit portions, allowing the system to adapt to varying image data requirements and maintain optimal cooling efficiency under different operating conditions.
Solution Approach 2:
The system implements feedback control by detecting the heat generation state of different drive circuit portions and using this information to control the cooling liquid circulation sequence. This feedback mechanism ensures that cooling is always directed to the portions generating the most heat, maximizing cooling efficiency regardless of the image data being processed.
4Productivity
If multiple thermal conductive members are used with dynamic circulation control, then cooling efficiency is enhanced, but device complexity increases
Solution Approach 1:
The cooling unit is designed with multi-functionality where a single controller manages multiple thermal conductive members and circulation paths. This universal control architecture allows the system to achieve high cooling efficiency through dynamic adaptation while avoiding the need for separate control systems for each cooling path, thereby limiting the increase in 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
Enhances cooling efficiency and maintains high ejection stability by effectively managing heat distribution and reducing the risk of short-circuits, thereby improving the performance of the liquid ejecting apparatus.
Implementation Method 1
a first thermal conductive member that is in contact with a first portion on the drive circuit, a second thermal conductive member that is in contact with a second portion on the drive circuit
Data Source
AI summary
A liquid ejecting apparatus includes a head that includes an ejecting portion that, upon receiving a drive signal, ejects liquid; a controller that performs control on circulation of liquid through the first flow passage, wherein the controller performs first control of circulating liquid through the first thermal conductive member and the second thermal conductive member in this order in the first flow passage when an amount of heat generated at the first portion is larger than an amount of heat generated at the second portion, and performs second control of circulating liquid through the second thermal conductive member and the first thermal conductive member in this order in the first flow passage when an amount of heat generated at the second portion is larger than an amount of heat generated at the first portion.