Hyperpigmented Toner Composite Pigment System Dielectric Loss

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Solution Overview

Problem

Hyperpigmented toners, particularly those containing black pigments, face challenges with high dielectric loss, which reduces charging efficiency and degrades image quality, making it difficult to achieve high pigment loading without compromising performance.

Innovation Solution

Incorporating a mixture of secondary colorants of different colors, including insulative pigments, into the toner composition to reduce dielectric loss while maintaining or exceeding the performance of toners with only primary black colorants, thereby allowing for higher pigment loading without negative impacts on charging or image quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If black pigment loading is increased to improve color density and blackness degree, then image quality is improved, but dielectric loss increases and charging efficiency decreases

Engineering Contradiction:
Improvecolor densityVSAvoiddielectric loss
Core Design Contradiction:
Illumination intensityVSLoss of energy

Solution Approach 1:

The patent uses a composite pigment system combining carbon black with alternative black pigments (such as iron oxide, manganese oxide, or organic black pigments) to create a toner composition that achieves high color density while reducing dielectric loss. This composite approach allows the toner to maintain excellent blackness degree and color density without the excessive dielectric loss associated with high concentrations of conventional carbon black.

Inventive Principle:
Principle #40Composite materials

2Illumination intensity

If black pigment loading is increased to improve color density, then image quality is improved, but charging efficiency deteriorates

Engineering Contradiction:
Improvecolor densityVSAvoidcharging efficiency
Core Design Contradiction:
Illumination intensityVSProductivity

Solution Approach 1:

The patent modifies the chemical composition parameters of the black pigment system by replacing a portion of carbon black with alternative black pigments having different electrical properties. This parameter change in the pigment composition allows the toner to achieve high color density while improving charging efficiency, as the alternative pigments have lower dielectric loss and better charging characteristics.

Inventive Principle:
Principle #35Parameter changes

3Illumination intensity

If conventional black pigments are used to achieve high color density, then blackness degree is improved, but conductive pathways form reducing charging performance

Engineering Contradiction:
Improveblackness degreeVSAvoidcharging performance
Core Design Contradiction:
Illumination intensityVSReliability

Solution Approach 1:

The patent extracts and removes a portion of the problematic carbon black component that forms conductive pathways, and replaces it with alternative black pigments that do not form conductive pathways. This extraction of the harmful component while maintaining the desired blackness degree through alternative pigments resolves the contradiction between high blackness degree and reliable charging performance.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentUS8846283B2Hyperpigmented toner
Publication Date: 2014.09.30 XEROX CORP

AI summary

The present disclosure describes hyperpigmented toner compositions containing a mixture of insulative color pigments, which toners exhibit reduced dielectric loss and improved tribo-charging.