Ink-jet Printer Head Measurement Electrode for Temperature Control
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Solution Overview
Problem
Conventional ink-jet printers face challenges in accurately measuring the temperature of the printer head, leading to inconsistent ink viscosity and printing quality due to the distance between the nozzles and the temperature measurement circuit, resulting in smears and defects from thermal expansion stresses during manufacturing.
Innovation Solution
A printer head design with laminated piezoelectric plates and a measurement electrode opposed to the ink pressurizing chambers allows for increased capacitance measurement, enabling accurate temperature calculation and reduced measurement errors, thus optimizing ink jetting pressure and minimizing thermal distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sensor electrodes are disposed to correspond to each individual electrode for capacitance measurement, then temperature measurement capability is achieved, but the printer head size increases due to required wiring areas
Solution Approach 1:
The patent merges the measurement electrode function with the common electrode structure. Instead of having separate sensor electrodes for each individual electrode, a single measurement electrode is disposed to face the common electrode, which is oppositely arranged to multiple individual electrodes. This combining approach enables temperature measurement through capacitance changes of the piezoelectric plates without requiring multiple separate sensor electrode wirings, thereby avoiding printer head size increase.
2Area of stationary object
If sensor electrodes with small area are used for capacitance measurement, then printer head size is kept small, but temperature measurement accuracy decreases
Solution Approach 1:
The patent combines multiple measurement functions into a single measurement electrode that faces the common electrode. This measurement electrode has a larger effective area compared to individual sensor electrodes, enabling accurate temperature measurement through capacitance changes while keeping the printer head size compact. The common electrode serves as a shared reference for all individual electrodes, allowing temperature measurement without requiring multiple small sensor electrodes.
3Device complexity
If thermistor is disposed on circuit board for temperature measurement, then device complexity is reduced, but measurement accuracy deteriorates due to long distance from nozzles
Solution Approach 1:
The patent uses the piezoelectric plates as an intermediary medium for temperature measurement. Instead of directly measuring ink temperature with a thermistor on the circuit board, the measurement electrode measures capacitance changes of the piezoelectric plates, which have been heated by the ink. The piezoelectric plates serve as a thermal intermediary that transfers temperature information from the ink to the measurement electrode, enabling accurate temperature measurement without direct contact with the ink or long-distance thermal conduction through the circuit board.
4Measurement precision
If capacitance measurement area is increased for better temperature accuracy, then measurement precision improves, but printer head size increases
Solution Approach 1:
The patent merges the measurement function with the existing common electrode structure, allowing the measurement electrode to have a large effective area for accurate capacitance measurement without adding extra space. The common electrode is oppositely arranged to multiple individual electrodes, providing a large measurement area that captures temperature variations across the piezoelectric plates while maintaining a compact printer head design.
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 design enhances printing quality by accurately measuring temperature changes, reducing smears and defects, and maintaining optimal ink viscosity control, while also preventing printer head size increase and manufacturing defects.
Implementation Method 1
According to the piezoelectric method, a piezoelectric plate is deformed, and by the pressure caused in the ink flow path at this time, ink is jetted
Implementation Method 2
The capacitance of the piezoelectric plates between the common electrode and the sensor electrodes is measured, and from the obtained capacitance, the temperature is calculated
Data Source
AI summary
A measurement electrode for capacitance measurement is disposed so as to be opposed to a common electrode with a second and a third piezoelectric plates in between and to be opposed to all ink pressurizing chambers with a first piezoelectric plate in between. The capacitance of the piezoelectric plate disposed between the common electrode and the measurement electrode is measured with a larger area, and from the measured capacitance, the temperature of the piezoelectric plate is calculated based on the capacitance-temperature characteristic of the piezoelectric plate. In order to generate a pressure suitable for the ink viscosity that changes according to the temperature, the change in the overall temperature of the printer head that changes according to the status of use of the printer is accurately measured.