Inkjet Nozzle Waveform Segmentation for Mist Adhesion
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Solution Overview
Problem
Ink jet printers using non-absorptive media face issues with ink droplets adhering to nozzle surfaces due to heat-induced viscosity changes and mist formation, leading to blockages and reduced print quality.
Innovation Solution
A printing apparatus with a head that discharges ink containing thermoplastic resin particles, utilizing a specific discharge waveform and heating unit to manage ink viscosity and prevent mist adherence, combined with a wiping mechanism to remove accumulated ink.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the medium is heated to accelerate ink drying and suppress ink droplet flowing, then the ink drying speed is improved, but the nozzle opening surface temperature increases causing ink mist to adhere and accumulate on the nozzle
Solution Approach 1:
The discharge waveform is segmented into multiple distinct phases (first expansion, contraction, second expansion, third expansion) with different functions. Each phase controls specific aspects of ink ejection to minimize mist generation while maintaining drying efficiency.
Solution Approach 2:
The discharge waveform dynamically adjusts pressure chamber volume through controlled expansion and contraction phases. The waveform transitions between expansion and contraction states to optimize ink ejection velocity and reduce mist formation at the nozzle opening surface.
2Reliability
If ink containing thermoplastic resin particles is used to form hard resin film and ensure rub resistance, then the print durability is improved, but the ink viscosity increases making mist more likely to adhere to the heated nozzle opening surface
Solution Approach 1:
The discharge waveform parameters are specifically optimized to control ink ejection with thermoplastic resin particles. The multi-phase waveform adjusts pressure changes to maintain ink flow stability despite increased viscosity from resin content, preventing mist adherence while preserving rub resistance.
3Device complexity
If a simple discharge waveform is used, then the device complexity is reduced, but minute ink droplets are generated along with main ink droplets causing nozzle blockage
Solution Approach 1:
The discharge waveform is divided into four distinct phases (first expansion, contraction, second expansion, third expansion) that work together to control ink ejection. This segmentation allows precise control over ink droplet formation to eliminate minute droplets while maintaining reasonable system complexity.
Solution Approach 2:
The discharge waveform employs periodic expansion and contraction cycles to control ink ejection. The alternating phases create controlled pressure changes that stabilize ink flow and prevent the formation of satellite droplets during the ejection process.
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 reduces ink adherence to nozzle surfaces, preventing blockages and ensuring consistent ink flow, thereby enhancing print quality and reliability on non-absorptive media.
Implementation Method 1
a heating unit that heats the aforementioned medium
Implementation Method 2
a control unit that drives the driving element by applying driving signals thereto to expand and contract the pressure chamber corresponding to the respective driving element so as to discharge ink droplets through the nozzle
Data Source
AI summary
A printing apparatus includes a head having a nozzle through which ink that contains thermoplastic resin particles and whose viscosity at 50° C. is equal to or greater than 2.1 mPa·s is discharged, a pressure chamber, and a driving element; an ink non-absorptive medium; a heating unit; and a control unit that applies driving signals to the driving element. In the printing apparatus, a discharge waveform generated by the driving signal includes a first expansion-element that expands the pressure chamber, a contraction-element that contracts the pressure chamber having been expanded by the first expansion-element, a second expansion-element that expands the pressure chamber having been contracted by the contraction-element, a third expansion-element that further expands the pressure chamber having been expanded by the second-expansion element, and a connection-element that connects an end terminal of the second expansion-element with a start terminal of the third expansion-element at the same potential.