Charge Roller Surface Treatment for Image Quality
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Solution Overview
Problem
Conventional charge rollers in electrographic image forming apparatuses suffer from decreased image quality due to touch marks caused by human contact, which leads to spots in halftone images, as the surface treatment methods do not effectively prevent foreign matter attachment and residual potential changes.
Innovation Solution
A charge member with a conductive elastic layer and a surface treatment layer containing isocyanate, polycarbonate, and fluorine-based resin is used, which maintains a residual potential of 12.16 V or less after corona discharge, preventing touch marks and ensuring image quality by reducing foreign matter attachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a surface treatment using isocyanate and polycarbonate is performed on the charge roller to harden the surface and increase release property, then foreign matter attachment is suppressed, but touch marks are left on the surface when handled, causing spots in halftone images and decreasing image quality
Solution Approach 1:
The patent applies a composite surface treatment layer containing isocyanate compound (1-10 parts by weight), polycarbonate compound (85-98 parts by weight), and fluorine-based resin (1-10 parts by weight). This composite formulation combines the hardening and release properties of isocyanate-polycarbonate with the low surface energy and anti-stick characteristics of fluorine-based resin, achieving both foreign matter resistance and touch mark prevention simultaneously
Solution Approach 2:
The patent optimizes the compositional parameters of the surface treatment layer, specifically controlling the weight ratios of isocyanate compound (1-10 parts), polycarbonate compound (85-98 parts), and fluorine-based resin (1-10 parts). This parameter optimization ensures the surface has sufficient hardness to resist foreign matter while maintaining low friction and anti-stick properties to prevent touch marks during handling
2Object-affected harmful factors
If the charge roller surface is hardened to prevent foreign matter attachment, then release property is improved, but residual potential increases after corona discharge, affecting charging performance
Solution Approach 1:
The fluorine-based resin component in the composite surface treatment layer contributes low surface energy and electrical insulation properties that help control residual potential. The balanced formulation ensures the surface remains sufficiently conductive for effective corona discharge charging while preventing excessive residual potential buildup that would degrade charging performance
Solution Approach 2:
The patent controls the content of fluorine-based resin (1-10 parts by weight) to optimize the electrical properties of the surface treatment layer. This parameter control ensures the surface has appropriate electrical conductivity for effective charging while limiting residual potential to maintain reliable charging performance across operating conditions
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 effectively suppresses touch marks and image quality degradation, allowing for easier handling and maintaining image quality even after human contact, by controlling residual potential and foreign matter attachment.
Implementation Method 1
a surface treatment using isocyanate and polycarbonate is performed on the surface of the charge roller to harden the surface
Implementation Method 2
when corona discharge is performed at a voltage of 6.0 [kV]
Data Source
AI summary
A charge member is positioned in contact with an image carrier and charges a surface of the image carrier. The charge member includes a support body, an elastic layer having conductivity, which is formed on the support body; and a first surface treatment layer, which contains isocyanate compound and polycarbonate compound, is formed on the elastic layer. Residual potential of the charge member in 0.1 [seconds] after corona discharge at a voltage of 6.0 [kV] is 12.16 [V] or less.