Brilliant Developer Toner Recess Structure Chargeability

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Solution Overview

Problem

Developers containing metallic pigments for image forming apparatuses face challenges in achieving high chargeability, leading to issues like fog and vertical streaks, which degrade print quality due to their large particle size and low surface area, and require excessive external additives that can contaminate equipment.

Innovation Solution

A brilliant developer with toner base particles containing a brilliant pigment and a binder resin, where some particles have a recess with an opening width of 11.2 ± 2.7 µm, improving chargeability and preventing external additive separation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If the particle size of developer containing metallic pigment is increased to maintain brilliance, then the brilliance is improved, but the chargeability deteriorates leading to fog

Engineering Contradiction:
ImprovebrillianceVSAvoidchargeability
Core Design Contradiction:
Illumination intensityVSReliability

Solution Approach 1:

The toner base particles are segmented to have a recessed portion, creating a non-uniform surface structure. This segmentation increases the effective surface area for charge accumulation while maintaining the overall large particle size needed for metallic pigment brilliance, thus resolving the contradiction between brilliance and chargeability

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The toner base particles have different local structures: a recessed portion that provides high surface area for chargeability and an outer surface that maintains the overall particle morphology for brilliance. This local quality differentiation allows simultaneous achievement of both brilliance and chargeability

Inventive Principle:
Principle #3Local quality

2Reliability

If the amount of external additive is increased to improve chargeability, then the chargeability is improved, but external additive particles separate and contaminate equipment causing vertical streaks

Engineering Contradiction:
ImprovechargeabilityVSAvoidvertical streaks
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The recessed portion is pre-formed in the toner base particles before external additive application. This preliminary structural preparation provides predetermined charge accumulation zones that reduce dependency on large amounts of external additives, preventing additive separation and vertical streak formation

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The recessed portion structure creates micro-cavities that replicate and distribute charge more effectively throughout the particle. This structural copying mechanism enhances chargeability without requiring excessive external additives, thereby preventing contamination and vertical streaks

Inventive Principle:
Principle #26Copying

3Illumination intensity

If the particle size of developer is increased to reduce pigment surface area, then the metallic pigment performance is improved, but the chargeability deteriorates due to low surface area

Engineering Contradiction:
Improvemetallic pigment performanceVSAvoidsurface area
Core Design Contradiction:
Illumination intensityVSArea of stationary object

Solution Approach 1:

The invention transitions from considering only the outer surface area of large particles to utilizing the internal surface area created by the recessed portion. This dimensional change allows large particles to have effectively increased surface area through the added internal cavity surfaces, maintaining metallic pigment performance while improving chargeability

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 brilliant developer enhances print quality by reducing fog and vertical streaks while maintaining high brilliance, as the specific surface area and recess structure effectively manage charge distribution and additive separation.

Implementation Method 1

As developers containing such metallic pigments are large in particle size, they are small in surface area per unit weight, and low in chargeability

Methodology Applied
Scientific EffectSurface area effect:

Implementation Method 2

by using static electricity, more specifically by applying predetermined high voltages to rollers in image forming units or the like as appropriate, the image forming apparatus sequentially adheres and transfers the developers to rollers, a paper sheet, or the like

Methodology Applied
Scientific EffectElectrostatic adhesion: Electrostatics

Data Source

PatentEP3839634A1Brilliant developer, developer container, image forming unit, and image forming apparatus
Publication Date: 2021.06.23 OKI ELECTRIC INDUSTRY CO LTD
  • EP3839634A1 patent drawingFigure 1
  • EP3839634A1 patent drawingFigure 2
  • EP3839634A1 patent drawingFigure 3~4

AI summary

A brilliant developer includes toner base particles containing a brilliant pigment and a binder resin, wherein some of the toner base particles each have a recess having an opening width of 11.2 ± 2.7 µm.