Piezoelectric Inkjet Nozzle Detection via Residual Oscillation
Solution Overview
Problem
Inkjet printers face productivity issues due to nozzle clogging, which leads to image quality degradation, as existing detection methods are not effective in maintaining high-speed printing without requiring re-printing of entire products.
Innovation Solution
A liquid droplet ejecting device with a drive waveform generation unit, detection unit, and state determination unit that detects abnormal ejection states by analyzing the relationship between residual oscillation waveforms and thresholds, allowing for real-time determination of nozzle and pressure chamber states without disrupting printing processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If continuous feed inkjet printing is performed at high speed, then productivity is improved, but nozzle clogging occurs more frequently leading to image quality degradation
Solution Approach 1:
The patent applies preliminary action by detecting nozzle abnormalities through residual oscillation analysis before they cause complete clogging or significant image quality degradation. The system continuously monitors the residual oscillation waveform characteristics and compares them against threshold values to identify early signs of nozzle problems, enabling preventive maintenance during continuous high-speed printing operations.
Solution Approach 2:
The patent implements feedback by using the counter electromotive voltage generated during piezoelectric element operation to detect residual oscillations. This feedback mechanism provides real-time information about nozzle status, allowing the system to adjust or alert operators about potential clogging issues while maintaining continuous printing at high speed.
2Difficulty of detecting and measuring
If residual oscillation detection is performed using period parameter analysis, then nozzle clogging detection capability is improved, but detection precision is insufficient for early-stage clogging
Solution Approach 1:
The patent applies parameter changes by shifting from period-based detection to amplitude-based detection of residual oscillations. Instead of analyzing the time period of oscillations, the system measures the amplitude (absolute value of counter electromotive voltage) and compares it against threshold values. This parameter change enables detection of early-stage clogging where amplitude degradation occurs before period changes become significant.
Solution Approach 2:
The patent substitutes mechanical/time-based detection methods with electrical field-based detection. By utilizing the counter electromotive voltage generated in the piezoelectric element, the system replaces mechanical oscillation period measurement with electrical signal amplitude analysis, providing more sensitive and precise detection of nozzle abnormalities.
3Productivity
If nozzle detection and restoration operations are performed during continuous printing, then productivity is maintained, but detection precision may be affected by printing operations
Solution Approach 1:
The patent implements continuity of useful action by enabling simultaneous printing and nozzle detection operations. The residual oscillation detection system operates during the natural idle periods between droplet ejections without interrupting the continuous printing process. This allows the system to maintain high productivity while continuously monitoring nozzle health through the counter electromotive voltage generated during normal piezoelectric element operation.
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 effective detection and maintenance of nozzle states, preventing clogging and maintaining high productivity by allowing for immediate restoration operations during continuous printing, thus ensuring consistent image quality.
Implementation Method 1
a piezoelectric element for applying pressure to ink within the pressure chamber
Implementation Method 2
oscillation of a nozzle surface (hereinafter referred to as "meniscus") after ink droplet ejection is propagated and the state of the meniscus is detected based on a change in the oscillation pattern of a counter electromotive voltage that is generated
Data Source
AI summary
A liquid droplet ejecting device is provided that includes a liquid droplet ejecting head having a nozzle, a pressure chamber that accommodates liquid and is in communication with the nozzle, and a piezoelectric element that is arranged to face the pressure chamber; a drive waveform generation unit configured to generate a drive waveform that drives the piezoelectric element and has a potential that varies with respect to a reference potential; a detection unit configured to detect a relationship between a detected potential of a residual oscillation waveform that is generated within the pressure chamber after driving the piezoelectric element and a first threshold corresponding to a potential higher than the reference potential; and a state determination unit configured to determine whether the nozzle and/or the pressure chamber is in an abnormal state based on the detected relationship between the detected potential and the first threshold.