W/O Emulsion Process Liquid for Plain Paper Image Quality

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Solution Overview

Problem

Inkjet image forming devices face challenges with feathering, bleeding, and curling when using plain paper as a recording medium, particularly due to the limitations of existing process liquids in terms of uniform application, storage, and transfer efficiency.

Innovation Solution

An image forming apparatus and method that employs a coating unit to apply a process liquid formed by emulsifying water and a low polarity solvent as a W/O emulsion, where the water is in the dispersed phase and the low polarity solvent is in the continuous phase, using a surfactant to prevent feathering, bleeding, and curling on plain paper.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a process liquid including a cationic high molecular compound is used to prevent bleeding and feathering, then image quality is improved, but the viscosity of the process liquid becomes high, making it difficult to uniformly apply and causing curling and waviness on plain paper

Engineering Contradiction:

Improveimage qualityVSAvoiduniform application

Core Design Contradiction:

Manufacturing precisionVSEase of operation

Solution Approach 1:

The patent changes the chemical composition parameters of the process liquid by using a non-ionic polymer instead of a cationic high molecular compound, and by adjusting the HLB value of the surfactant to a specific range (10-20), thereby achieving uniform application while maintaining image quality

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs a non-ionic polymer that can be easily disposed of or degraded, avoiding the need for complex recovery processes, and uses a surfactant system that can be readily adjusted or replaced

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

2Manufacturing precision

If water-absorbing resin fine particles are used to prevent bleeding and feathering, then image quality is improved, but the fine particles may absorb moisture during storage and aggregate, making it difficult to uniformly apply and causing image distortion

Engineering Contradiction:

Improveimage qualityVSAvoiduniformity during storage

Core Design Contradiction:

Manufacturing precisionVSStability of the object's composition

Solution Approach 1:

The patent extracts the water-absorbing function from the fine particles and replaces it with a surfactant-based mechanism that prevents bleeding and feathering without requiring moisture absorption, thereby eliminating the aggregation problem during storage

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the mechanism from physical moisture absorption to chemical surfactant action, and adjusts the HLB value parameter to achieve the desired balance between water repellency and uniform application

Inventive Principle:

Principle #35Parameter changes

3Manufacturing precision

If an aqueous process liquid is applied to plain paper sheet, then bleeding and feathering are suppressed, but curling and waviness tend to occur

Engineering Contradiction:

Improveimage qualityVSAvoidflatness of paper

Core Design Contradiction:

Manufacturing precisionVSShape

Solution Approach 1:

The patent changes the composition parameters by using a non-ionic polymer with specific molecular weight and combining it with a surfactant of controlled HLB value, which modifies the interaction with paper fibers to prevent curling while maintaining bleeding suppression

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite process liquid system combining non-ionic polymer and surfactant, where the surfactant component specifically addresses the curling issue while the polymer maintains the bleeding prevention function

Inventive Principle:

Principle #40Composite materials

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 enables the formation of high-quality images on plain paper by preventing feathering, bleeding, and curling, while allowing for easy and uniform application of the process liquid and efficient storage.

Implementation Method 1

the process liquid is formed by emulsifying, by a first surfactant, water including a water-soluble polymer and a low polarity solvent which is not compatible with the water, wherein the water and the low polarity solvent are emulsified as a W/O emulsion in which the water is in a dispersed phase and the low polarity solvent is in a continuous phase

Methodology Applied

Scientific EffectEmulsion: Emulsion

Implementation Method 2

the process liquid is formed by emulsifying, by a first surfactant, water including a water-soluble polymer and a low polarity solvent which is not compatible with the water

Methodology Applied

Scientific EffectSurfactant: Surfactant

Data Source

PatentUS8944556B2Image forming apparatus and image forming method

Publication Date: 2015.02.03 RICOH CO LTD

AI summary

Disclosed is an image forming apparatus including a head configured to discharge an aqueous recording liquid onto a recording medium; and a coating unit configured to apply a process liquid onto the recording medium, wherein the process liquid is formed by emulsifying, by a first surfactant, water including a water-soluble polymer and a low polarity solvent which is not compatible with the water, wherein the water and the low polarity solvent are emulsified as a W/O emulsion in which the water is in a dispersed phase and the low polarity solvent is in a continuous phase.