Inkjet Nozzle Vibration Control for Clogging Prevention
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Solution Overview
Problem
Ink printing apparatuses face challenges in maintaining nozzle functionality due to ink viscosity increases during inactivity, leading to clogging and altered droplet ejection, particularly when using inks with different drying behaviors, resulting in suboptimal print quality and potential nozzle failure.
Innovation Solution
The method involves controlling printing elements with pulse-shaped signals to set the ink into oscillation during inactivity periods, determining the number of vibration cycles based on the duration since the last ink ejection and the ink's drying properties, ensuring the oscillation decays before the next droplet is printed, thus preventing clogging and maintaining desired droplet size and direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple vibration cycles are performed in succession to prevent ink drying, then the risk of nozzle clogging is reduced, but ink may leak onto the nozzle plate
Solution Approach 1:
The patent applies dynamics by making the number of vibration cycles variable rather than fixed. The controller dynamically adjusts the number of vibration cycles based on real-time detection of ink droplet ejection status and idle time duration. This dynamic adaptation allows the system to perform sufficient vibrations to prevent clogging while stopping before causing ink leakage, resolving the contradiction between reliability and harmful effects.
Solution Approach 2:
The patent implements feedback by continuously monitoring whether ink droplets are being ejected from nozzles and using this information to control the vibration cycles. The controller detects ejection status and adjusts vibration cycle count accordingly, creating a closed-loop system that prevents both clogging (by vibrating when idle) and leakage (by stopping vibrations when ejection occurs), thus resolving the technical contradiction.
2Device complexity
If a fixed number of vibration cycles is used for all ink types, then the control system is simple, but some inks experience insufficient mixing while others experience excessive vibrations
Solution Approach 1:
The patent transitions from a static fixed vibration cycle count to a dynamic variable count based on actual printing conditions. The controller adjusts the number of vibration cycles according to the specific ink type, drying properties, and ejection status, enabling optimal mixing for each ink while maintaining manageable system complexity through algorithmic control rather than hardware complexity.
Solution Approach 2:
The patent applies parameter changes by varying the number of vibration cycles based on ink-specific parameters such as drying behavior and viscosity characteristics. Different ink types receive different vibration cycle counts optimized for their specific properties, allowing the system to handle diverse ink formulations effectively without requiring a completely different control approach for each ink type.
3Reliability
If vibration cycles are performed to mix ink viscosity, then clogging is prevented, but the oscillation may interfere with the next droplet ejection
Solution Approach 1:
The patent uses dynamics by timing the vibration cycles to end before the next droplet ejection occurs. The controller dynamically calculates when to stop vibrations based on the detected ejection status and idle time, ensuring that oscillations have decayed sufficiently to avoid interfering with subsequent droplet ejection while still providing adequate mixing to prevent clogging, thus resolving the precision contradiction.
Solution Approach 2:
The patent applies preliminary action by performing vibration cycles during idle time periods before the next droplet ejection is required. The vibrations are initiated in advance during periods when no droplets are being ejected, allowing the ink to be mixed and viscosity to be maintained without interfering with the upcoming ejection process, thereby preventing clogging while preserving ejection accuracy.
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 reduces the risk of nozzle clogging and maintains print quality by mixing ink viscosity and ensuring ink droplets are ejected accurately, even with varying ink types, thereby extending the operational life of the print head and maintaining image integrity.
Implementation Method 1
the actuator is activated with a predetermined waveform so that the ink meniscus at the output of the nozzle is set into vibration without ejecting an ink droplet. Via the vibration, the ink at the end of the nozzle channel is mixed
Data Source
AI summary
In a method for controlling printing elements of an ink print head, an idle time between the ejection of two dots from the same nozzle is determined. In the event that the idle time exceeds a predetermined threshold (ΔtS), a determined number of vibration cycles is performed (e.g. in immediate succession). The number of vibration cycles is determined based on the idle time, such that more vibration cycles are performed the longer that the idle time lasts between the ejections of two dots from the same nozzle.