Developer Set Carrier Resistivity and Particle Size for Image Density

Solution Overview

Problem

In electrophotography, the incorporation of carriers with different resistivities and particle sizes between image forming units can lead to the formation of white lines or density decreases in images, particularly when transferring toner images, due to charge interactions and carrier exchange during the imaging process.

Innovation Solution

The use of a developer set comprising a first developer with a low volume resistivity and small particle diameter carrier, and a second developer with higher volume resistivity and larger particle diameter carrier, helps to suppress the formation of white lines by ensuring proper charge neutralization and image density consistency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If carriers with different resistivities and particle sizes are used between image forming units, then charge management and image density consistency are improved, but device complexity increases

Engineering Contradiction:

Improveimage density consistencyVSAvoiddevice complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies local quality by assigning different carrier properties (volume resistivity and particle diameter) to different image forming units based on their specific functional requirements. The first image forming unit uses carriers with lower volume resistivity and smaller particle diameter, while the second unit uses carriers with higher volume resistivity and larger particle diameter. This localized differentiation optimizes charge management and image density consistency for each unit's specific role in the imaging process.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent implements parameter changes by systematically varying key carrier parameters (volume resistivity and particle diameter) across different image forming units. The first carrier has volume resistivity of 1×10^6 to 1×10^10 Ω·cm and particle diameter of 15 to 30 μm, while the second carrier has volume resistivity of 1×10^10 to 1×10^14 Ω·cm and particle diameter of 30 to 50 μm. These controlled parameter variations enable optimized charge neutralization and image density consistency without requiring complete redesign of the system.

Inventive Principle:

Principle #35Parameter changes

2Object-affected harmful factors

If carriers with different resistivities are used between image forming units, then white line formation is suppressed, but carrier exchange control becomes more difficult

Engineering Contradiction:

Improvewhite line formationVSAvoidcarrier exchange control

Core Design Contradiction:

Object-affected harmful factorsVSEase of operation

Solution Approach 1:

The patent applies local quality by assigning different carrier properties (volume resistivity and particle diameter) to different image forming units based on their specific functional requirements. The first image forming unit uses carriers with lower volume resistivity and smaller particle diameter, while the second unit uses carriers with higher volume resistivity and larger particle diameter. This localized differentiation optimizes charge management and image density consistency for each unit's specific role in the imaging process.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent uses the intermediate transfer member as a mediator that facilitates controlled carrier transfer between image forming units. The intermediate transfer member receives toner images from the first image forming unit and transfers them to the second image forming unit, enabling controlled carrier exchange. This intermediary mechanism allows the system to benefit from different carrier properties in each unit while maintaining manageable carrier exchange through the transfer interface.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If smaller particle diameter carriers are used, then charge neutralization is improved, but carrier incorporation into toner image increases

Engineering Contradiction:

Improvecharge neutralizationVSAvoidcarrier incorporation

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

The patent applies local quality by assigning different carrier properties (volume resistivity and particle diameter) to different image forming units based on their specific functional requirements. The first image forming unit uses carriers with lower volume resistivity and smaller particle diameter, while the second unit uses carriers with higher volume resistivity and larger particle diameter. This localized differentiation optimizes charge management and image density consistency for each unit's specific role in the imaging process.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent segments the carrier system into two distinct carrier types with different properties, each optimized for specific image forming units. The first carrier (smaller particle diameter, lower resistivity) is used in the first image forming unit where charge neutralization is critical, while the second carrier (larger particle diameter, higher resistivity) is used in the second unit where minimizing carrier incorporation is prioritized. This segmentation allows each carrier type to excel at its specific function without compromising overall system performance.

Inventive Principle:

Principle #1Segmentation

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

This configuration effectively reduces the occurrence of white lines and density variations in images, even under low-temperature and low-humidity conditions, by ensuring effective charge management and carrier interaction within the image forming apparatus.

Implementation Method 1

the incorporation of carriers with different resistivities and particle sizes between image forming units can lead to the formation of white lines or density decreases in images, particularly when transferring toner images, due to charge interactions and carrier exchange during the imaging process

Methodology Applied

Scientific EffectElectrostatic charge interaction: Electrostatics

Implementation Method 2

The use of a developer set comprising a first developer with a low volume resistivity and small particle diameter carrier, and a second developer with higher volume resistivity and larger particle diameter carrier, helps to suppress the formation of white lines by ensuring proper charge neutralization

Methodology Applied

Scientific EffectCharge neutralization: Electrostatics

Data Source

PatentUS10514652B2Image forming apparatus and developer set

Publication Date: 2019.12.24 FUJIFILM BUSINESS INNOVATION CORP

AI summary

A developer set includes a first developer and a second developer. The first developer includes a first toner and a first carrier. The second developer includes a second toner and a second carrier. The second toner is a toner that includes a flaky brilliant pigment, a toner that includes a white pigment, or a transparent toner. The second carrier has a higher volume resistivity than the first carrier and has a larger volume average particle diameter than the first carrier.