Leakage Current Detection Circuit for Liquid Ejecting Apparatus Drive Stability
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Solution Overview
Problem
Existing liquid ejecting apparatuses face instability due to leakage currents generated in drive circuits, leading to unintended heat generation and reduced operational stability, particularly when using piezoelectric elements for ink ejection.
Innovation Solution
Incorporating a leakage current detection circuit connected to the amplifier circuit in the drive circuit, which detects and manages leakage currents to prevent heat generation and maintain stability by controlling the drive signal output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a drive circuit with amplifier circuit is used to drive piezoelectric elements, then sufficient electric current can be supplied to the piezoelectric elements, but leakage current is generated causing unintended heat generation and reduced operational stability
Solution Approach 1:
The patent implements a feedback mechanism where the drive circuit monitors its own operation and adjusts parameters to minimize leakage current. The control circuit receives feedback about the drive signal characteristics and modifies the amplification process to reduce harmful leakage effects while maintaining sufficient current output for piezoelectric element actuation.
Solution Approach 2:
The patent introduces an intermediary control circuit between the signal source and the amplifier circuit. This intermediary circuit pre-processes the signal and controls the amplifier's operation to reduce leakage current generation, acting as a mediator that optimizes the interaction between different circuit components to eliminate harmful effects.
2Power
If high voltage signal amplification is performed in the drive circuit, then the drive signal can effectively actuate piezoelectric elements, but leakage current based on the high voltage signal is generated causing heat generation
Solution Approach 1:
The patent applies preliminary action by pre-conditioning the high voltage signal before amplification. The control circuit prepares the base drive signal with appropriate characteristics that minimize leakage current generation during subsequent amplification, addressing the heat generation issue before it occurs in the main amplification stage.
Solution Approach 2:
The patent dynamically adjusts circuit parameters during operation to minimize leakage current. The control circuit modifies amplification factors, timing parameters, and signal waveforms based on operating conditions, changing electrical parameters in real-time to reduce heat generation while maintaining effective drive signal voltage for piezoelectric element actuation.
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
The solution effectively reduces the risk of heat-related issues and improves the operational stability of the drive circuit and the liquid ejecting apparatus by accurately detecting and mitigating leakage currents, ensuring precise ink ejection and extended apparatus lifespan.
Implementation Method 1
a piezoelectric element 60 that is driven by a drive signal VOUT based on a drive signal COM
Data Source
AI summary
A liquid ejecting apparatus includes a driven element that is driven by a drive signal; an ejection head that ejects a liquid when the driven element is driven; a drive circuit that outputs the drive signal, the drive circuit including an amplifier circuit that includes a first transistor and amplifies, based on an amplification voltage and through an operation of the first transistor, a base drive signal based on which the drive signal is generated; and a leakage current detection circuit that detects a leakage current in the drive circuit. The leakage current detection circuit is electrically connected to the first transistor included in the amplifier circuit to which the amplification voltage is supplied.