Printhead Control Circuit Abnormality Detection
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Solution Overview
Problem
Existing liquid ejecting apparatuses, such as ink jet printers, face malfunctions due to poor accuracy in signal supply, leading to printhead malfunctions and increased likelihood of short circuits from liquid mist particles, which are not effectively addressed by detecting only high-voltage signal abnormalities.
Innovation Solution
A printhead control circuit that performs abnormality detection by outputting signals to wires with different voltage potentials, ensuring normal operation of both high- and low-voltage signals, and includes a signal circuit to manage these signals and detect abnormalities in the printhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If only high-voltage signal abnormalities are detected, then the detection complexity is reduced, but the reliability of printhead operation is insufficient because both high- and low-voltage signal abnormalities need to be detected
Solution Approach 1:
The patent combines high-voltage signal detection and low-voltage signal detection into a single integrated abnormality detection circuit within the printhead. The detection circuit receives both high-voltage signals (e.g., 42V drive signals) and low-voltage signals (e.g., 3.3V control signals) through separate input terminals, processes both signals simultaneously, and outputs a single abnormality detection result. This merging approach maintains comprehensive monitoring of both voltage levels while avoiding the need for separate detection systems, thus improving reliability without proportionally increasing device complexity.
2Reliability
If abnormality detection is performed for both high- and low-voltage signals, then the reliability of signal supply is improved, but the device complexity increases due to additional detection circuits
Solution Approach 1:
The abnormality detection circuit is designed with multi-functionality to handle both high-voltage and low-voltage signal detection using a single integrated circuit structure. The circuit includes multiple input terminals that can accommodate different voltage levels and signal types, and a unified processing mechanism that evaluates abnormalities across both voltage domains. This universal design allows the same detection circuit to perform multiple functions (high-voltage monitoring, low-voltage monitoring, and integrated abnormality determination) without requiring separate dedicated circuits for each function, thereby improving signal supply reliability while controlling circuit complexity.
3Reliability
If liquid mist particles are present around the printhead, then the likelihood of short circuit increases, but adding protective measures increases device complexity
Solution Approach 1:
The patent implements preliminary abnormality detection by continuously monitoring signal integrity before liquid mist particles can cause short circuits. The detection circuit proactively identifies signal abnormalities (such as voltage drops, noise, or transmission failures) that may indicate the presence of liquid mist particles or other interference. By detecting and reporting abnormalities in advance, the system can take preventive actions (such as stopping operation or alerting the user) before actual short circuits occur, thereby improving reliability without requiring complex physical protective barriers or isolation mechanisms.
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 solution enhances the reliability of the printhead by accurately detecting signal abnormalities, reducing the likelihood of malfunctions and short circuits, thereby improving print quality and apparatus performance.
Implementation Method 1
drives a piezoelectric element provided for a printhead by using a drive signal and thereby ejects liquid
Implementation Method 2
The liquid mist particles floating within the liquid ejecting apparatus are very small and are therefore charged due to the Lenard effect
Data Source
AI summary
In a printhead control circuit causing a printhead to execute printing, the printhead performing abnormality detection in response to a first signal inputted to a second terminal in a state in which the potential of a first terminal is a first potential and a second signal inputted to the second terminal in a state in which the potential of the first terminal is a second potential, one of the first and second potentials is higher than the potentials of the first and second signals, and a signal circuit is configured to output the first and second signals. The signal circuit outputs the first signal to the second wire electrically coupled to the second terminal in a state in which the first wire is being supplied with a first voltage signal at the first potential and outputs the second signal to the second wire after outputting the first signal in a state in which the first wire is being supplied with a second voltage signal at the second potential, which is different from the first potential, to cause the printhead to execute the abnormality detection in response to the first signal, the second signal, the first voltage signal, and the second voltage signal.