Ink Set Segmentation for Bleeding and Clogging
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Solution Overview
Problem
The use of ink containing a pigment and polymer emulsion in printing apparatuses leads to increased solids content, causing clogging and reduced image quality due to bleeding and interference with the formation of high-quality images, resulting in decreased glossiness and surface roughness.
Innovation Solution
An ink set comprising a first ink with a pigment and a water-soluble resin having an anionic group, a second ink with a reactive component that reacts with the first ink, and a third ink with a polymer emulsion and a water-soluble resin, where the pKa of the reactive component is adjusted to prevent polymer emulsion precipitation, ensuring reduced bleeding and maintaining glossiness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If ink containing polymer emulsion is used to reduce bleeding, then bleeding is reduced, but solids content increases causing clogging of ejection openings
Solution Approach 1:
The invention divides the ink into three separate inks: first ink containing pigment and water-soluble resin with anionic group, second ink containing reactive component, and third ink containing polymer emulsion and water-soluble resin. This segmentation allows each component to perform its specific function without interfering with others, preventing both bleeding and clogging.
Solution Approach 2:
The invention extracts the polymer emulsion from the pigment ink by placing it in a separate third ink. This extraction prevents the polymer emulsion from increasing solids content in the pigment-containing ink, thereby preventing clogging while still allowing the polymer emulsion to form a protective coating that reduces bleeding.
2Strength
If polymer emulsion is added to ink to form coating film, then water and rubbing resistance is improved, but glossiness is reduced due to surface roughness
Solution Approach 1:
The invention applies the reactive component (second ink) before applying the polymer emulsion (third ink). This preliminary action allows the reactive component to react with and remove excess polymer emulsion, creating a smoother surface that maintains glossiness while the polymer emulsion coating still provides water and rubbing resistance.
3Object-affected harmful factors
If reactive component is applied to reduce bleeding, then bleeding is reduced, but polymer emulsion reacts and flocculates reducing glossiness
Solution Approach 1:
The invention carefully controls the pKa parameter of the reactive component in the second ink to be lower than the pKa of the anionic group in the first ink but higher than the pKa of the anionic group in the third ink. This parameter control ensures selective reaction: the reactive component reacts with excess polymer emulsion to reduce bleeding, but does not cause flocculation that would reduce glossiness.
4Reliability
If ejection opening diameter is increased to reduce clogging, then clogging is reduced, but ink droplet diameter increases reducing definition and glossiness
Solution Approach 1:
The invention extracts the polymer emulsion from the pigment ink by placing it in a separate third ink. This extraction reduces the solids content in the first and second inks, allowing the use of smaller ejection openings without causing clogging, thereby maintaining both definition and glossiness.
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 ink set effectively reduces bleeding and maintains high glossiness by ensuring the pigment reacts with the reactive component while the polymer emulsion does not, preventing clogging and surface roughness, thus producing high-quality printed articles.
Implementation Method 1
the multivalent metal salt and the carboxy group come into contact with each other on the printing medium to form an insoluble substance, thereby reducing the occurrence of bleeding
Implementation Method 2
the ink dropped on the printing medium is heated so that the polymer emulsion forms a coating film on the surface of the printing medium, thereby fixing the image
Implementation Method 3
The pKa of the reactive component in the second ink is lower than the pKa of the anionic group of the water-soluble resin in the first ink and higher than the pKa of the anionic group of the water-soluble resin in the third ink
Data Source
AI summary
An ink set including a first ink containing a pigment and a water-soluble resin having an anionic group, a second ink containing substantially no pigment and a reactive component, and a third ink containing a polymer emulsion and a water-soluble resin having an anionic group. The pKa of the reactive component is lower than the pKa of the anionic group of the water-soluble resin in the first ink and higher than the pKa of the anionic group of the water-soluble resin in the third ink.