Electrostatic Ink Concentration Without Centrifuges
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Solution Overview
Problem
Existing electrostatic printing processes face challenges in concentrating inks to high solids content without degrading print quality, as high liquid carrier concentrations can irreversibly change particle structures, affecting print quality and making inks unsuitable for use.
Innovation Solution
A method and apparatus that use a chargeable conveyor and a moving surface with applied potential to concentrate electrostatic inks continuously, removing liquid carrier while maintaining the integrity of resin particles, allowing for higher solids content without the need for centrifuges, and enabling efficient production from low to high solids content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If electrostatic inks are concentrated to high solids content (30-35 wt% or higher) by traditional methods, then the liquid carrier concentration increases, but the particle structures irreversibly change and print quality degrades
Solution Approach 1:
The patent replaces the mechanical centrifugal separation system with an electrostatic field-based concentration system. Instead of using centrifuges that mechanically separate particles through rotation, the invention uses charged electrodes to create an electrostatic field that selectively removes liquid carrier from the ink while keeping toner particles intact on the photoconductive surface, thereby concentrating the ink without degrading particle structure or print quality
Solution Approach 2:
The patent changes the physical state and concentration parameters of the electrostatic ink composition during the concentration process. By controlling the electrostatic field strength, electrode spacing, and processing conditions, the system progressively increases the solids content from low to high concentrations (up to 30-35 wt% or higher) while maintaining particle integrity through controlled parameter adjustment rather than harsh mechanical or chemical treatment
2Quantity of substance
If centrifugal separators are used to concentrate inks, then solids content increases, but equipment cost and footprint increase
Solution Approach 1:
The patent replaces bulky mechanical centrifugal separation equipment with a compact electrostatic field-based concentration system using charged electrodes and a photoconductive surface. This substitution eliminates the need for large centrifuges and complex mechanical separation apparatus, significantly reducing equipment footprint and complexity while achieving the same ink concentration effect through electrostatic field control
Solution Approach 2:
The patent makes the electrostatic printing system itself multi-functional by enabling it to perform both image formation and ink concentration operations. The same photoconductive surface and electrode system used for printing also serves as the concentration apparatus, eliminating the need for separate dedicated centrifuge equipment and reducing overall system complexity
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
This approach allows for the continuous production of concentrated inks with solids content up to 40 weight percent or higher, maintaining print quality and eliminating the need for costly centrifuges, thus improving efficiency and reducing equipment footprint.
Implementation Method 1
passing the ink between a charged conveyor and a first electrode, where a potential is applied between the conveyor and the electrode, such that the chargeable particles adhere to the conveyor
Implementation Method 2
passing the ink on the conveyor past a moving surface, where a potential is applied between the conveyor and the moving surface, such that some of the liquid carrier is removed to increase the concentration of the chargeable particles in the liquid carrier on the conveyor
Data Source
Figure 1
Figure 2~3
AI summary
The present application relates to a method for concentrating an ink for an electrostatic printing process, wherein the method comprises the steps of: (a) providing the ink for an electrostatic printing process, the ink comprising chargeable particles in a liquid carrier; (b) passing the ink between a chargeable conveyor and a first electrode, wherein a potential is applied such that the ink becomes adhered to the chargeable conveyor; (c) passing the ink on the conveyor past a moving surface, wherein the ink contacts the moving surface and a potential is applied between the conveyor and the moving surface, such that the chargeable particles are disposed to move toward the conveyor and some of the liquid carrier is removed to increase the concentration of the chargeable particles in the liquid carrier on the conveyor to form a concentrated ink on the conveyor, the conveyor and the moving surface then diverging from one another, such that substantially all of the concentrated ink remains on the conveyor; (d) removing the concentrated ink from the conveyor and transferring it to a storage vessel. An apparatus for carrying out this method is also disclosed.