Electron Beam Crosslinked Charging Member Suppressing Toner Adhesion
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Solution Overview
Problem
Charging members with elastic layers made from acrylonitrile-butadiene rubber (NBR) are prone to toner adhesion and compression set, leading to uneven charging performance and image defects in electrophotographic apparatuses, especially when using styrene-butadiene rubber (SBR) as a raw material rubber.
Innovation Solution
A charging member with an electroconductive support and an electroconductive elastic layer formed through electron beam irradiation of a vulcanized rubber mixture containing NBR and SBR, where the SBR has a specific ratio of 1,2-vinyl, cis-1,4, and trans-1,4 bonds, reducing toner adhesion and compression set.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If an elastic layer using only NBR as raw material rubber is used, then processability is improved, but toner adhesion increases due to polar groups in NBR
Solution Approach 1:
The patent uses a composite rubber material consisting of NBR and SBR in a specific ratio (70:30 to 90:10 by mass). This composite approach combines the processability benefits of NBR with the low adhesion properties of SBR, resolving the contradiction between ease of manufacture and toner adhesion prevention.
2Object-affected harmful factors
If SBR is added to NBR to suppress toner adhesion, then toner adhesion is reduced, but compression set increases due to electron beam irradiation
Solution Approach 1:
The patent optimizes the compositional parameters of the rubber mixture (NBR:SBR ratio between 70:30 and 90:10 by mass) and controls the electron beam irradiation dose (10-100 kGy). By carefully adjusting these parameters, the patent achieves a balance where toner adhesion is suppressed while compression set is minimized through enhanced crosslinking.
Solution Approach 2:
The patent applies electron beam irradiation specifically to the surface layer of the charging member to create a crosslinked structure. This localized treatment modifies the surface properties to reduce toner adhesion and suppress compression set without affecting the bulk material properties, thereby resolving the contradiction between adhesion suppression and compression set prevention.
3Object-affected harmful factors
If the surface is subjected to electron beam irradiation to suppress toner adhesion, then toner adhesion is reduced, but compression set occurs due to deformation over time
Solution Approach 1:
The patent applies electron beam irradiation as a preliminary treatment to the surface of the charging member before actual use. This pre-treatment creates a crosslinked structure that simultaneously suppresses toner adhesion and prevents future compression set by stabilizing the material structure against deformation over time.
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 toner adhesion and compression set, ensuring stable charging performance and high-quality electrophotographic images by adjusting the molecular structure of the SBR to enhance the crosslinked structure and hardness of the elastic layer.
Implementation Method 1
the elastic layer is formed through irradiation of an electron beam onto a surface of a vulcanized rubber layer
Implementation Method 2
a cross-linked product of a rubber mixture comprising an acrylonitrile-butadiene rubber and a styrene-butadiene rubber
Data Source
Figure 1~2
Figure 3~4
AI summary
Provided is a charging member having an elastic layer to which components derived from a developer hardly adhere even when the charging member is used for a long time period and in which elastic layer the occurrence of compression set is suppressed The charging member includes: an electroconductive support; and an electroconductive elastic layer, in which the elastic layer is formed through irradiation of an electron beam onto a surface of a rubber layer formed of a crosslinked product of a rubber mixture containing an acrylonitrile-butadiene rubber and a styrene-butadiene rubber; the styrene-butadiene rubber has a 1,2-vinyl bond, and at least one selected from a cis-1,4 bond and a trans-1,4 bond; and a ratio of the numbers of moles of the 1,4 bonds to a total number of moles of the 1,2-vinyl bond, the cis-1,4 bond, and the trans-1,4 bond is 31 mol% or more and 61 mol% or less.