Printhead Circulation Channel with Pressure-Aligned Nozzles
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Solution Overview
Problem
Inkjet printers face challenges in achieving improved print quality and ink flux due to variations in absolute pressure along the printhead's circulation channel, leading to inefficient fluid ejection and print quality degradation.
Innovation Solution
The implementation of a recirculation channel with a combination of high drop weight (HDW) and low drop weight (LDW) nozzles positioned at different points to align absolute pressure, allowing for optimized fluid flow and print quality by varying nozzle exit areas and operational pressures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single type of nozzle is used throughout the circulation channel, then the device complexity is reduced, but print quality and ink flux vary due to pressure variations along the channel
Solution Approach 1:
The patent applies local quality by differentiating nozzle types based on their position in the circulation channel. HDW nozzles are placed in regions where higher ink flux is needed, while LDW nozzles are positioned where finer print quality is required. This spatial differentiation of nozzle characteristics according to local pressure conditions optimizes both print quality and ink flux without requiring a completely complex redesign of the entire system.
2Productivity
If HDW nozzles are used to increase ink flux, then productivity is improved, but print quality may deteriorate due to larger drop size
Solution Approach 1:
The patent segments the nozzle population into two distinct types: HDW nozzles for high ink flux applications and LDW nozzles for high print quality applications. By dividing the nozzle function across different types rather than using a single uniform nozzle design, the system can simultaneously achieve both high productivity through HDW nozzles and high print quality through LDW nozzles in different locations along the circulation channel.
3Manufacturing precision
If LDW nozzles are used to improve print quality, then manufacturing precision is improved, but ink flux and productivity decrease
Solution Approach 1:
The patent positions LDW nozzles in specific regions of the circulation channel where fine print quality is the primary requirement, while HDW nozzles are positioned in regions where high ink flux is more critical. This local optimization allows each nozzle type to perform its specialized function effectively, ensuring that print quality is improved where needed without sacrificing overall productivity.
Data Source
AI summary
An example printhead includes a circulation channel having an inlet for receiving a fluid and an outlet for expelling the fluid, a first nozzle fluidically coupled to the circulation channel, the first nozzle being operable at a first absolute pressure, and a second nozzle fluidically coupled to the circulation channel, the second nozzle being operable at a second absolute pressure, the absolute second pressure being lower than the first absolute pressure. The absolute pressure in the circulation channel decreases as the fluid flows from the inlet to the outlet, and the first nozzle is positioned closer to the inlet of the circulation channel than the second nozzle.