Inkjet Ink Polymer Copolymer Beading Prevention

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Solution Overview

Problem

Inkjet recording technologies face challenges with image density and beading issues on non-permeable media due to pigment ink permeation into paper, leading to decreased surface density and stability problems during high-speed printing.

Innovation Solution

The development of an ink formulation incorporating a copolymer with specific structure units that enhance pigment agglomeration and adhesion, including ethylene oxide and propylene oxide groups, which improve image density and prevent beading by adjusting the glass transition temperature and hydrophilic properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If pigment concentration in ink is increased to improve image density, then image density increases, but ink viscosity increases which degrades discharging stability

Engineering Contradiction:

Improveimage densityVSAvoiddischarging stability

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The patent changes the chemical composition parameters of the ink by introducing a specific polymer with hydrophilic groups (ethylene oxide and propylene oxide) and aromatic rings. This polymer modifies the ink's physical properties, allowing high pigment concentration to be maintained while viscosity and discharging stability are controlled through the polymer's glass transition temperature and hydrophilic characteristics.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite ink formulation combining pigment particles, water, and a specifically designed polymer compound. The polymer acts as a binding matrix that holds pigment particles together, enabling the system to achieve high image density while maintaining appropriate flow properties through the composite structure's controlled glass transition temperature and hydrophilic balance.

Inventive Principle:

Principle #40Composite materials

2Ease of manufacture

If pigment ink is used on water-absorbing recording media like plain paper, then the pigment permeates into the paper, but this causes decreased surface pigment density and lower image density

Engineering Contradiction:

Improvecompatibility with plain paperVSAvoidimage density

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent introduces a polymer intermediary substance that acts as a binding matrix between the pigment particles and the recording medium. This polymer with controlled glass transition temperature and hydrophilic groups prevents pigment from过度 permeating into the paper while maintaining adhesion, thus preserving surface pigment density and achieving high image density on plain paper.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Manufacturing precision

If pigment is present on the surface of non-permeable recording media, then image can be formed, but mottle or beading appears due to pigment accumulation

Engineering Contradiction:

Improveimage formation on coated paperVSAvoidmottle and beading

Core Design Contradiction:

Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The patent modifies the ink's physical parameters by incorporating a polymer with specific glass transition temperature and hydrophilic group content. This changes the ink's spreading behavior and drying characteristics, preventing pigment accumulation that causes mottle and beading while still enabling effective image formation on non-permeable surfaces like coated paper.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates local quality differentiation in the ink formulation through the polymer structure, where hydrophilic groups interact with water and aromatic rings interact with pigment particles. This localized interaction pattern controls pigment distribution uniformly across the recording medium surface, preventing beading while maintaining image density.

Inventive Principle:

Principle #3Local quality

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 achieves high image density and resolution on various media while maintaining storage stability and preventing beading, even during high-speed printing.

Implementation Method 1

a polymer comprising a structure unit represented by the following Chemical formula 1 and a structure unit represented by the following Chemical formula 2 or the following Chemical formula 3... (CH2-CH2-O)n-(CH2-CH(OH))-...

Methodology Applied

Scientific EffectHydrophilic interaction: Hydrophile

Implementation Method 2

the polymer includes a structure unit having a naphthyl group or a biphenyl group... M and Q each, independently represent naphthyl groups or biphenyl groups

Methodology Applied

Scientific EffectPi-pi stacking:

Data Source

PatentUS10633549B2Ink, ink accommodating container, image forming method, and image forming device

Publication Date: 2020.04.28 RICOH CO LTD

AI summary

An ink includes water; a coloring material, and a polymer including a structure unit represented by the following Chemical formula 1 and a structure unit represented by the following Chemical formula 2 or the following Chemical formula 3,where R and T each, independently represent hydrogen atoms or methyl groups, L and N each, independently represent single bonds or carbonyl groups, M and Q each, independently represent naphthyl groups or biphenyl groups, p represents an integer of from 2 to 12, and q represents an integer of from 1 to 3.