Liquid Ejection Head Wire Damage Detection
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Solution Overview
Problem
Existing liquid ejecting apparatuses face issues with false detection of wire damage due to voltage fluctuations in commercial power supplies, leading to unnecessary restriction of ejection operations, as they rely solely on voltage value for wire damage detection.
Innovation Solution
A liquid ejection head unit with a first wire for supplying a fixed potential and a second wire for transmitting a pulse signal, along with counters that change based on potential changes, and an ejection restriction unit that restricts operations based on count values from both counters to accurately determine wire damage and prevent false positives.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If wire damage detection is based only on voltage value, then detection simplicity is improved, but measurement precision deteriorates due to voltage fluctuations causing false detections
Solution Approach 1:
The detection system is segmented into two independent detection channels: one monitoring voltage value changes and another monitoring pulse signal changes. Each channel operates independently to detect different aspects of wire integrity, allowing the system to cross-validate results and eliminate false positives caused by voltage fluctuations alone.
Solution Approach 2:
The pulse signal serves as an intermediary reference that is less susceptible to voltage fluctuations. By comparing changes in both voltage and pulse signals, the system uses the pulse signal as a mediator to distinguish between actual wire damage and normal voltage variations in the power supply.
2Reliability
If ejection operation is restricted based on false wire damage detection, then system reliability is improved by preventing potential failures, but productivity deteriorates due to unnecessary operation restrictions
Solution Approach 1:
The system implements feedback through dual-parameter monitoring where the detection results from both voltage changes and pulse signal changes are fed back to the ejection control unit. This feedback mechanism allows the system to make informed decisions about operation restriction only when both parameters indicate actual wire damage, preventing unnecessary productivity loss.
Solution Approach 2:
The system changes from monitoring a single parameter (voltage) to monitoring multiple parameters (voltage and pulse signals). This parameter expansion allows the system to distinguish between normal voltage fluctuations and actual wire damage, ensuring that ejection operations are restricted only when truly necessary, thus maintaining both reliability and productivity.
Data Source
AI summary
A liquid ejection head unit includes an ejection unit that ejects a liquid, a first wire configured to supply a fixed potential used for driving the ejection unit, a second wire configured to transmit a pulse signal that defines an ejection timing of the liquid in the ejection unit, a first counter whose count value changes based on a potential change in the first wire, a second counter whose count value changes based on a potential change in the second wire, and an ejection restriction unit that restricts an ejection operation of the liquid in the ejection unit according to a count value of the first counter and a count value of the second counter.