Electrostatic Inkjet Dryer for Faster Aqueous Ink Evaporation
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Solution Overview
Problem
Existing inkjet printers face challenges in drying aqueous ink efficiently without reducing production speed or increasing costs, as current dryers struggle to handle heavier media with larger ink amounts, leading to ink smudging and impaired image quality due to limited diffusion rates in the boundary layer.
Innovation Solution
Incorporating an electrostatic field generator to increase airflow near the ink surface by charging the media and using electric fields to repel vapor clouds, enhancing evaporation rates without expanding the printer's footprint or increasing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the thermal output of the dryer is increased to dry ink more effectively, then the ink drying efficiency is improved, but the cost and footprint of the printer significantly increase
Solution Approach 1:
The patent changes the physical parameter of air flow velocity near the ink surface by applying electrostatic forces to accelerate vapor removal. Instead of increasing thermal output, the system modifies the diffusion rate parameter through electrostatic acceleration of air molecules, achieving faster drying without adding thermal capacity or increasing device complexity
Solution Approach 2:
The patent replaces the mechanical/thermal drying system with an electrostatic field-based system. Rather than relying on thermal convection or high-velocity mechanical air flow, the invention uses electrostatic forces to accelerate vapor molecules away from the ink surface, substituting a complex mechanical heating and air moving system with a simpler electrostatic field generation system
2Productivity
If external air flow is increased to enhance vapor diffusion, then the evaporation rate is improved, but the ink image placement is disturbed and image quality is adversely impacted
Solution Approach 1:
The patent applies local quality by creating a highly localized electrostatic field effect immediately above the ink surface. The electrostatic acceleration is concentrated in the Knudsen layer and boundary layer regions, affecting only the vapor molecules near the ink while leaving the bulk air flow and ink image undisturbed. This localized approach enhances evaporation without compromising image placement accuracy
Solution Approach 2:
The patent introduces an electrostatic field as an intermediary mechanism between the ink surface and the bulk air flow. The electrostatic field acts as a mediator that accelerates vapor molecules in the boundary layer without requiring direct mechanical disturbance of the air flow, thus enhancing evaporation rates while maintaining image stability
3Manufacturing precision
If the media weight and ink amount are increased to improve image quality, then the ink coverage is improved, but the dryer cannot sufficiently dry the ejected ink at higher speeds
Solution Approach 1:
The patent changes the diffusion rate parameter in the boundary layer by applying electrostatic acceleration to vapor molecules. This parameter change allows the system to handle higher ink loads and heavier media at increased production speeds, as the electrostatic field continuously accelerates vapor removal regardless of ink quantity, breaking the traditional speed-drying capacity limitation
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 significantly improves ink drying efficiency, doubling evaporation rates and maintaining image quality by repelling vapor clouds and enhancing diffusion, thus allowing higher production speeds with heavier media and larger ink amounts.
Implementation Method 1
an electrostatic charge generator positioned to direct electrostatic charge toward the media being moved by the media transport to improve an evaporation rate in material applied to the media being moved by the media transport
Implementation Method 2
using an electrostatic field generator to increase airflow near the liquid surface by charging the media and using electric fields to repel vapor clouds
Implementation Method 3
The evaporation rate of a liquid is determined by the vapor pressure at the liquid surface and the rate of diffusion of vapor through the air above the liquid
Implementation Method 4
The evaporation rate of a liquid is determined by the vapor pressure at the liquid surface and the rate of diffusion of vapor through the air above the liquid
Data Source
AI summary
An inkjet printer includes one or more devices to increase evaporation rates within one or more dryers in the inkjet printer. An electrostatic charge generator can be positioned before a dryer to charge media and liquid materials ejected onto the media before the media enters the dryer to increase evaporation rates. An electric field generator within the dryer can be operated to generate an electric field that is directed toward the media to increase the movement of the vapor cloud away from the media being carried by a media transport within the dryer. Additionally, a corona generator can be coupled to an AC high frequency current to generate a corona wind to increase evaporation rates within the dryer.