Inkjet Nozzle Viscosity Control via Residual Vibration Detection
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Solution Overview
Problem
Conventional inkjet recording apparatuses consume ink wastefully due to the discharge of ink droplets from all nozzles, even when the ink viscosity near the nozzles is suitable, leading to increased running costs and potential issues like image defects and nozzle clogging.
Innovation Solution
A liquid droplet ejecting device that performs idle discharge or liquid-state recovery ejection by detecting residual vibrations in the pressure chamber to determine the viscosity of ink and control the drive voltage of piezoelectric elements, discharging thickened ink only from necessary nozzles, thereby reducing waste and maintaining optimal ink viscosity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ink droplets are discharged from all nozzles to maintain proper ink viscosity, then nozzle clogging is prevented, but ink consumption increases and running costs increase
Solution Approach 1:
The patent applies local quality by individually controlling each nozzle based on its specific ink viscosity state. The controller determines which nozzles require idle discharge based on detected viscosity changes, applying the flushing action only where needed rather than uniformly to all nozzles, thus preventing clogging locally while minimizing overall ink consumption
Solution Approach 2:
The patent implements feedback by detecting ink viscosity changes in each pressure chamber and using this information to control idle discharge operations. The system monitors viscosity indicators and adjusts the flushing operation accordingly, creating a closed-loop control system that responds to actual nozzle conditions rather than operating blindly
2Manufacturing precision
If idle discharge is performed from all nozzles to maintain image quality, then image defects are prevented, but running costs increase due to unnecessary ink consumption
Solution Approach 1:
The controller selectively applies idle discharge only to nozzles that show signs of viscosity thickening or potential image defects, rather than uniformly flushing all nozzles. This localized approach maintains image quality in affected areas while avoiding unnecessary ink consumption in properly functioning nozzles
Solution Approach 2:
The system performs partial idle discharge action only when and where needed based on viscosity detection, rather than excessive uniform action across all nozzles. The controller adjusts the flushing intensity and frequency to match the actual requirements of each nozzle, avoiding over-flushing
3Loss of substance
If viscosity detection and selective idle discharge control is implemented, then ink consumption is reduced, but device complexity increases
Solution Approach 1:
The system uses the existing piezoelectric elements and pressure chamber structure to detect viscosity changes through their inherent electrical characteristics, rather than requiring separate dedicated sensors. The piezoelectric elements serve dual functions of both actuation and sensing, allowing the system to monitor its own state and adjust operations accordingly
Solution Approach 2:
The piezoelectric elements perform multiple functions: they actuate ink ejection during normal operation and simultaneously serve as sensors for detecting ink viscosity changes during idle discharge control. This multi-functionality reduces the need for additional components and simplifies the overall system architecture
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 effectively suppresses ink waste consumption, reduces running costs, and maintains image quality by ensuring only necessary nozzles discharge thickened ink, preventing nozzle clogging and image defects.
Implementation Method 1
piezoelectric elements to compress the ink in the pressure chambers
Implementation Method 2
by applying a slight vibration to meniscus (ink surface), the increase in the viscosity of the ink positioned near the openings of the nozzles, and ejecting the ink droplet is made stable
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A liquid droplet ejecting device (200) that includes multiple pressure chambers (27) communicating with multiple nozzles (20), to contain liquid; a vibration plate (30), to constitute elastic walls of the pressure chambers, disposed extending along the pressure chambers; multiple pressure generating elements (35) disposed facing the multiple chambers respectively via the vibration plate; a drive waveform generator (212) to generate drive waveform data that indicates a shape of a drive waveform for driving the multiple pressure generating elements; a residual vibration detector (240) to detect a residual vibration waveform occurring within the pressure chamber after the pressure generating elements are driven; and a controller (211) to determine the necessity of liquid-state recovery ejection for discharging thickened liquid, based on the detected residual vibration, and to cause the liquid-state recovery ejection to be performed upon determining that liquid-state recovery ejection is needed.