Droplet Deposition Nozzle Meniscus Instability Control
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Solution Overview
Problem
Droplet deposition apparatuses face meniscus instability issues at high print frequencies, leading to droplet deviation and anomalies such as forking and drop merging, which result in visible artefacts in printed output, especially when printing at certain high frequency bands that correspond to forbidden pixel periods.
Innovation Solution
A method is introduced to reduce nozzle meniscus instability by determining a jitter delay value based on forbidden pixel periods, adjusting the pixel period to fall outside these frequencies, thereby generating actuating element signals that prevent or minimize meniscus instability through the use of a control system and processing circuitry within the droplet deposition apparatus.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high print frequencies are used to increase productivity, then printing speed is improved, but meniscus instability occurs leading to droplet deviation and anomalies
Solution Approach 1:
The system dynamically adjusts the pixel period in real-time based on the detected print frequency. When the print frequency approaches a forbidden frequency, the pixel period is modified to shift the operating frequency away from the resonant condition, thereby maintaining stable droplet ejection at high printing speeds without sacrificing reliability
Solution Approach 2:
The invention changes the pixel period parameter dynamically to avoid forbidden frequencies. By monitoring the print frequency and adjusting the pixel period accordingly, the system transitions operating parameters to maintain stability while preserving high productivity
2Stability of the object's composition
If pixel period is adjusted to avoid forbidden frequencies, then meniscus stability is improved, but print frequency must be modified
Solution Approach 1:
The system continuously monitors print frequency and dynamically adjusts the pixel period in real-time. This dynamic adaptation allows the system to maintain meniscus stability by avoiding forbidden frequencies while minimizing the impact on print frequency and overall productivity
3Manufacturing precision
If jitter delay value is applied to adjust pixel period, then droplet anomalies are reduced, but additional processing complexity is introduced
Solution Approach 1:
The system employs feedback control by monitoring the print frequency and comparing it against known forbidden frequencies. Based on this feedback, the pixel period is automatically adjusted using jitter delay values, thereby improving droplet placement precision through a closed-loop control mechanism
Solution Approach 2:
The invention replaces complex mechanical adjustments with electronic/digital control mechanisms. By using software-based frequency monitoring and pixel period adjustment through jitter delay, the system achieves precise droplet placement without requiring complex mechanical modification
Data Source
AI summary
A method for reducing instability of a nozzle meniscus of a droplet deposition apparatus. The method includes the steps of receiving first and second data blocks for respective first and second line pixels, receiving a data set of forbidden pixel periods, determining a first jitter delay value based on the forbidden pixel periods, generating first and second print data based on the first and second data blocks, the first print data defining a first holding period and one or more drive pulses and the second print data defining one or more drive pulses; wherein the first and second print data generate first and second actuating element signals that cause an actuating element to eject at least one droplet from a nozzle, wherein the first jitter delay value adjusts a first pixel period, defined by the drive pulses, to fall outside of the forbidden pixel periods to reduce nozzle meniscus instability.