Liquid Ejecting Head Drive Circuit Cooling for Thermal Stability
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Solution Overview
Problem
The operation of the analog conversion circuit in a liquid ejecting apparatus becomes unstable due to heat generated by the transistor pair when generating drive signals for the liquid ejecting head, which can propagate and affect the circuit's performance.
Innovation Solution
Incorporating a first cooling mechanism to cool the first transistor pair and a second cooling mechanism to cool the analog conversion circuit, the first and a second cooling mechanism to cool the analog conversion circuit, which includes a heat sink and a fan to dissipate heat from the transistor pair and the analog conversion circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a transistor pair is used to generate drive signals with large amplitude, then the drive signal generation capability is improved, but heat is generated that propagates to the analog conversion circuit causing unstable operation
Solution Approach 1:
The patent divides the drive signal generation circuit into separate functional blocks: an analog conversion circuit and a transistor pair circuit. By segmenting the circuit and providing separate cooling mechanisms for each block, the heat generated by the transistor pair is isolated from the analog conversion circuit, preventing thermal interference while maintaining drive signal generation capability.
Solution Approach 2:
The patent introduces cooling mechanisms as intermediary elements between the transistor pair and the analog conversion circuit. These cooling mechanisms act as thermal mediators that dissipate heat from the transistor pair before it can propagate to the analog conversion circuit, thereby protecting the circuit's stable operation.
2Power
If the transistor pair operates at high power to generate drive signals, then the drive signal amplitude is sufficient, but heat accumulation causes thermal instability in the circuit
Solution Approach 1:
The patent converts the harmful heat generated by the transistor pair into a manageable parameter by introducing dedicated cooling mechanisms. The cooling mechanisms actively dissipate the heat, transforming it from a harmful thermal effect into a controlled thermal management problem, thereby maintaining both high power output and temperature stability.
Solution Approach 2:
The patent changes the thermal management parameters by introducing active cooling mechanisms that alter the temperature profile of the circuit. By actively managing heat dissipation, the system maintains the transistor pair at operating temperatures suitable for high power generation while preventing heat accumulation that would cause instability.
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
Stabilizes the operation of the analog conversion circuit by effectively managing heat generated during drive signal generation, ensuring stable performance and preventing thermal instability.
Implementation Method 1
a first cooling mechanism that cools the first transistor pair
Implementation Method 2
heat generated by the transistor pair may propagate to the analog conversion circuit
Implementation Method 3
a second cooling mechanism that cools the analog conversion circuit
Implementation Method 4
heat generated by the transistor pair may propagate to the analog conversion circuit
Data Source
AI summary
A liquid ejecting apparatus includes a liquid ejecting head that is driven by a first drive signal to eject a liquid, an analog conversion circuit that converts a digital first waveform signal designating a waveform of the first drive signal into an analog second waveform signal designating the waveform of the first drive signal, a first transistor pair that includes two bipolar transistors generating the first drive signal based on the second waveform signal, a first cooling mechanism that cools the first transistor pair, and a second cooling mechanism that cools the analog conversion circuit.