Thermal Inkjet Printhead Minimum Discharge Energy Detection
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Solution Overview
Problem
Existing methods for determining minimum discharge energy in thermal inkjet printheads face challenges in accurately measuring minute temperature changes, leading to decreased signal-to-noise ratios and interference from external disturbances.
Innovation Solution
A printing apparatus and method that utilize electrothermal transducers, temperature detection elements, and a measurement unit to detect peak voltage changes, comparing them with a threshold to determine the minimum discharge energy by adjusting energy supply until the peak voltage meets the threshold, thereby minimizing external disturbance influence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If temperature detection elements are used to measure minute temperature changes (0.5°C to 1.0°C) for determining minimum discharge energy, then measurement capability is provided, but the signal-to-noise ratio decreases due to external disturbance influence
Solution Approach 1:
The patent introduces a reference temperature detection element that does not contact the electrothermal transducer as an intermediary reference point. By comparing the temperature detection element's reading with the reference element's reading, the system calculates temperature change while compensating for external disturbances like ambient temperature fluctuations, thereby improving the signal-to-noise ratio without sacrificing measurement capability
Solution Approach 2:
The system continuously monitors temperature changes and uses this feedback to adjust measurements in real-time. By comparing sequential temperature readings and calculating differences, the system can identify actual temperature changes caused by the electrothermal transducer while filtering out external noise through the reference element comparison mechanism
2Reliability
If energy is increased to ensure normal ink bubbling and discharge, then reliable ink discharge is achieved, but the printhead lifetime is shortened due to heater damage from excessive energy
Solution Approach 1:
The patent determines the minimum discharge energy by precisely measuring the temperature change threshold that indicates successful ink bubbling. By identifying this minimum threshold through accurate temperature monitoring and using it to set the operating energy level, the system ensures reliable ink discharge while avoiding the excessive energy that would damage heaters and shorten printhead lifetime
Solution Approach 2:
Instead of applying excessive energy to ensure discharge, the patent uses temperature detection to identify the precise minimum energy threshold required for successful ink discharge. By applying only this partial (minimum sufficient) amount of energy rather than excessive energy, the system achieves reliable discharge while preserving printhead longevity
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
Enables accurate determination of minimum discharge energy while suppressing external disturbance effects, ensuring reliable ink discharge and extending printhead lifetime.
Implementation Method 1
Heat generating resistive elements (heaters) are formed in the pressure chamber of the element substrate, and ink is discharged from the orifices by the discharge energy generated by the heat generating resistive elements
Implementation Method 2
a temperature detection element formed by a thin film resistor via an insulation film and detecting the temperature information of each nozzle
Data Source
AI summary
A printing apparatus measures a temperature of an electrothermal transducer by a corresponding temperature detection element, detects, based on the measured temperature, a peak voltage which indicates a point of change, from a state where ink is discharged normally from a printhead to a state where the ink is not discharged from the printhead, and compares the peak voltage with a threshold value. The measurement, detection, and comparison are repeated until the peal voltage becomes equal to or more than the threshold value. Energy supplied to the electrothermal transducer at a time in which the peak voltage is determined to be equal to or more than the threshold is determined to be minimum discharge energy.