Inkjet Ejection State Determination Using Position-Specific Vibration Ranges
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Solution Overview
Problem
Ink jet printers face challenges in accurately determining the ejection state of multiple ejection units due to differences in physical properties, such as compliance and Helmholtz resonance frequency, leading to incorrect determination of ejection abnormalities.
Innovation Solution
A printing apparatus with a driving signal generation unit, piezoelectric elements, pressure chambers, and a detection unit that generates and analyzes residual vibration signals to determine the ejection state of each unit, using distinct ranges for central and peripheral ejection units to account for varying physical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single predetermined range is used to determine ejection state for all ejection units, then the determination process is simple, but the measurement precision deteriorates due to physical property variations between different ejection units
Solution Approach 1:
The patent applies local quality by assigning different determination ranges to different ejection units based on their physical properties. Specifically, central ejection units use a first determination range while peripheral ejection units use a second determination range, allowing each unit to be evaluated according to its characteristic compliance and resonance frequency rather than using a uniform standard
Solution Approach 2:
The patent changes the determination parameters (range values) according to the physical properties of different ejection units. By setting different compliance values and resonance frequency ranges for central and peripheral units, the system adapts the evaluation criteria to match the actual physical characteristics of each group of ejection units
2Measurement precision
If the determination range is optimized for central ejection units, then central unit determination precision is improved, but peripheral unit determination accuracy deteriorates due to range mismatch
Solution Approach 1:
The patent implements local quality by creating region-specific determination ranges: a first determination range for central ejection units and a second determination range for peripheral ejection units. This allows each region to have optimized parameters matched to its physical characteristics, preventing the range mismatch that would occur with a single universal range
3Ease of operation
If ejection state determination uses a unified approach for all units, then the operation is simple, but false abnormality detection increases due to physical property differences
Solution Approach 1:
The patent reduces false abnormality detection by applying local quality through position-based determination ranges. The control unit automatically selects the appropriate range (first for central, second for peripheral) based on the ejection unit's position, maintaining operational simplicity while improving detection accuracy by accounting for physical property variations
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 approach allows for precise determination of the ejection state of both central and peripheral ejection units, reducing the likelihood of erroneous abnormality detection and ensuring accurate printing.
Implementation Method 1
a first piezoelectric element which is displaced according to the driving signal, a first pressure chamber whose inside is filled with a liquid and in which a pressure in the inside is increased or decreased due to the displacement of the first piezoelectric element based on the driving signal
Implementation Method 2
detects change of an electromotive force of the first piezoelectric element as a first residual vibration signal based on change of the pressure in the inside of the first pressure chamber, which is generated after the driving signal is supplied to the first piezoelectric element
Data Source
AI summary
A printing apparatus includes a piezoelectric element which is displaced according to a driving signal; a first ejection unit and a second ejection unit that include nozzles capable of ejecting; a detection unit that detects a first and second residual vibration signal; and a determination unit that determines an ejection state of the liquid in the first ejection unit to be normal in a case where a cycle of a waveform indicated by the first residual vibration signal belongs to a first range and determines an ejection state of the liquid in the second ejection unit to be normal in a case where a cycle of a waveform indicated by the second residual vibration signal belongs to a second range, in which a part or all of the second range includes a range which is not included in the first range.