Liquid Ejecting Apparatus Droplet Merging Waveform Control
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Solution Overview
Problem
Ink with high viscosity tends to form longer tails and is prone to mist generation during ejection from a nozzle, leading to lower print image quality.
Innovation Solution
A liquid ejecting apparatus with a control unit that generates a drive signal with specific waveforms to manage pressure changes in a pressure compartment, allowing for the ejection of a first liquid droplet followed by a second droplet that merges with the first before landing on a medium.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If ink with high viscosity is used, then the ink can maintain better flow stability, but it forms longer tails and is prone to mist generation during ejection
Solution Approach 1:
The patent divides the ejection process into multiple discrete droplets (first droplet, second droplet, third droplet) ejected at different timings. By segmenting the ink ejection into controlled pulses, the system manages the tail formation and merging process to reduce mist generation while maintaining flow stability of high viscosity ink.
Solution Approach 2:
The patent causes the second droplet to merge with the first droplet, and the third droplet to merge with the merged first and second droplets. This merging process consolidates the ink material into a single larger droplet, preventing the formation of mist by ensuring complete coalescence of ejected ink portions.
2Manufacturing precision
If multiple pulses are supplied to eject multiple droplets for merging, then droplet size control is improved, but the drive waveform complexity increases
Solution Approach 1:
The drive waveform is segmented into distinct expansion and contraction phases with specific timing relationships. The expansion waveform ejects each droplet, while the contraction waveform prepares for the next ejection. This segmentation allows precise control of droplet ejection timing and size while maintaining a systematic approach to waveform design.
Solution Approach 2:
The patent employs periodic expansion and contraction waveforms supplied at specific intervals to the pressure compartment. This periodic action rhythmically controls the ejection of multiple droplets, enabling precise timing control for droplet merging while using repetitive, manageable waveform patterns rather than complex arbitrary waveforms.
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
The solution effectively suppresses mist generation by ensuring precise droplet merging and control of droplet size, thereby maintaining print image quality.
Implementation Method 1
a piezoelectric element causes a pressure compartment that is in communication with a nozzle to contract in accordance with a drive signal that includes a pulse for ejecting ink from the nozzle
Implementation Method 2
a drive element that causes pressure changes in a liquid present inside the pressure compartment in accordance with a drive signal
Data Source
AI summary
A liquid ejecting apparatus comprises a liquid ejecting head having a drive element that is driven in accordance with a drive signal to eject liquid droplets from a nozzle. The drive signal comprises a first drive waveform including a first contraction waveform to eject a first liquid droplet and a second drive waveform including a second contraction waveform to eject a second liquid droplet which merges with the first liquid droplet before the first liquid droplet lands onto a medium. The first contraction waveform includes a first segment waveform along which the potential changes, a second segment waveform along which the potential is kept, and a third segment waveform along which the potential changes. The second contraction waveform includes a fourth segment waveform along which the potential changes, a fifth segment waveform along which the potential is kept, and a sixth segment waveform along which the potential changes.