Amphoteric Polymer Fixer Ink for Inkjet Printing
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Solution Overview
Problem
Inkjet printers face slow printing speeds due to the slow dry time of inks and bleed control algorithms, which can compromise print quality and speed, especially when using surfactants that improve dry times but often reduce edge acuity and optical density.
Innovation Solution
A water-soluble or water-dispersible amphoteric polymer with a cationic and anionic charge ratio greater than 1 is used in a fixer ink that forms a water-insoluble solid precipitate when mixed with anionic charged inkjet inks, enhancing print quality and speed without affecting edge acuity or optical density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If surfactants or penetrants are added to improve dry time, then printing speed is improved, but edge acuity and optical density decrease
Solution Approach 1:
The patent introduces a fixer ink as an intermediary substance applied between the substrate and the colorant ink. This fixer ink contains polymers that form a protective layer, allowing the colorant to be fixed without requiring surfactants that would compromise edge acuity. The fixer ink mediates between the substrate and colorant, enabling faster drying while preserving print quality.
Solution Approach 2:
The fixer ink is applied in advance before the colorant ink, preparing the surface to accept and retain the colorant. This preliminary action creates a protective layer that enables subsequent faster drying without sacrificing edge acuity, as the fixer layer is already in place to hold the colorant firmly.
2Productivity
If surfactants or penetrants are added to improve dry time, then printing speed is improved, but optical density decreases
Solution Approach 1:
The fixer ink serves as an intermediary that enhances the optical density of the printed image. By applying the fixer ink first, it creates a layer that increases the optical density through its polymer content, which then allows the colorant to be fixed more effectively, resulting in higher optical density without compromising printing speed.
Solution Approach 2:
The patent changes the chemical parameters of the ink system by introducing a fixer ink with specific polymer concentrations and compositions. This parameter change enables the system to achieve higher optical density while maintaining fast drying speeds, as the fixer ink's chemical properties are optimized to enhance colorant fixation without requiring additional surfactants.
3Reliability
If pigments are used instead of dyes to improve water-fastness and light-fastness, then print quality is improved, but ink formulation complexity increases
Solution Approach 1:
The fixer ink acts as an intermediary that simplifies pigment-based ink formulation. By applying the fixer ink first, it creates a protective layer that enhances the water-fastness and light-fastness of pigment inks without requiring complex dispersants or surfactants. The fixer layer mediates between the pigment particles and the substrate, reducing formulation complexity while maintaining print quality.
4Illumination intensity
If fixer ink is applied to precipitate colorant and polymer, then optical density and chroma are improved, but additional printing step is added
Solution Approach 1:
The patent merges the fixer ink application with the existing printing process by using the same inkjet printhead to deposit both the fixer ink and the colorant ink. This combining of functions eliminates the need for separate fixation equipment, reducing process complexity while still achieving improved optical density and chroma through the precipitation mechanism.
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 amphoteric polymer-based fixer ink stabilizes colorants, improving optical density and chroma while allowing for faster printing speeds and reliable jetting across a wide pH range, maintaining print quality without the drawbacks of traditional surfactants.
Implementation Method 1
the amphoteric polymer forms a water insoluble solid precipitate when mixing with an anionic charged ink jet ink
Data Source
AI summary
This disclosure provides an ink jettable fixer ink including a water soluble or water dispersible amphoteric polymer, wherein the amphoteric polymer contains both a cationic charge and an anionic charge within the same molecule, wherein the mole ratio of cationic charge to anionic charge is greater than 1; wherein the ink jettable fixer ink does not contain a colorant; and wherein the amphoteric polymer forms a water insoluble solid precipitate when mixing with an anionic charged ink jet ink. These fixer inks when used with aqueous colorant containing ink jet inks give improved optical density and chroma.