Developing Member Surface Layer Resin Composition for Leak Resistance
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Solution Overview
Problem
Electrophotographic developing members face challenges in preventing toner adhesion (filming) in low-temperature and low-humidity environments and ensuring leak resistance under high voltage applications, leading to potential electrical breakdown and image quality issues.
Innovation Solution
A developing member with a surface layer comprising a urethane resin and an acrylic resin, both having specific structural units, and an electronically conductive filler like carbon black, which improves dispersibility and phase separation, enhancing flexibility, hydrophobicity, and electroconductivity while reducing water absorbability and adhesiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an electronically conductive filler is dispersed into a binder resin to impart electroconductivity to the surface layer, then electroconductivity is improved, but if the dispersion is insufficient, aggregates of the electronically conductive filler are formed and leak may occur
Solution Approach 1:
The patent changes the chemical parameters of the binder resin by introducing specific structural units (acrylic resin with carboxyl groups and urethane resin with isocyanate groups) that modify the resin's dispersion characteristics. These parameter changes enable uniform distribution of electronically conductive fillers while maintaining electroconductivity and preventing aggregate formation.
Solution Approach 2:
The patent creates a composite surface layer material combining multiple resin components (acrylic resin and urethane resin with specific structures) and electronically conductive filler. This composite approach achieves synergistic effects where the specific resin combination provides both electroconductivity and uniform filler dispersion, preventing aggregation.
2Reliability
If a surface layer is provided on an elastic layer to improve abrasion resistance and charge imparting property, then durability and toner charging are improved, but toner adhesion (filming) occurs in low-temperature and low-humidity environments
Solution Approach 1:
The patent modifies the chemical structure parameters of the surface layer resin by incorporating specific units (acrylic resin with carboxyl groups at specific positions and urethane resin with isocyanate groups) that change the resin's interaction with toner. These parameter changes reduce toner adhesion in low-humidity environments while maintaining abrasion resistance.
Solution Approach 2:
The patent applies different functional characteristics to different parts of the surface layer through the use of multiple resin components with specific structures. The acrylic resin provides hydrophobicity to prevent toner adhesion, while the urethane resin provides abrasion resistance and charge imparting properties, creating local functional differentiation.
3Manufacturing precision
If high voltage is applied to a developing member to improve image quality, then electrophotographic image quality is improved, but electric leak occurs causing transverse streaked density unevenness
Solution Approach 1:
The patent changes the electrical parameters of the surface layer by introducing specific resin structures (acrylic resin with carboxyl groups and urethane resin with isocyanate groups) that modify the layer's electroconductivity and leak resistance. These parameter changes enable the surface layer to maintain appropriate electroconductivity for image quality while preventing electric leak at high voltages.
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 prevents toner adhesion and ensures high electroconductivity and leak resistance, enabling stable output of high-quality electrophotographic images across diverse environments.
Implementation Method 1
if the dispersion of the electronically conductive filler into the binder resin is insufficient, aggregates of the electronically conductive filler are formed in the surface layer and leak may occur in the aggregates
Implementation Method 2
incorporating an acrylic resin having predetermined physical properties in a polyether-based urethane resin... toner adhesion in a high-temperature and high-humidity environment is suppressed
Implementation Method 3
a toner is moved to an electrophotographic photosensitive member (drum) from a developing member, which are in contact with each other by the action of pressure
Implementation Method 4
a photosensitive member is charged electrically by a charging unit and an electrostatic latent image is formed by means of a laser
Data Source
AI summary
A high-quality developing member which excels in filming resistance and excels in leak resistance despite high electroconductivity is provided. The developing member includes an electroconductive substrate, an elastic layer formed on the substrate, and a surface layer which covers a surface of the elastic layer. The surface layer includes a first resin which has, between two adjacent urethane linkages, a structure represented by the structural formula (1) and one or both of structures selected from the group consisting of a structure represented by the structural formula (2) and a structure represented by the structural formula (3), a second resin which has a structure represented by the structural formula (4) and one or both of structures selected from the group consisting of a structure represented by the structural formula (5) and a structure represented by the structural formula (6), and an electronically conductive filler.