Regulating Member Segmentation for Image Quality
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Solution Overview
Problem
Conventional electrophotographic image forming apparatuses face issues with image defects such as low density portions and vertical streaks due to developer sticking and fusing to the regulating member, while increasing developer charge quantity to suppress fogging leads to regulation defects and further image defects.
Innovation Solution
A developing apparatus with a regulating member having a conductive supporting member and a contact member with varying resistivity, where the contact portion is disposed on the upstream side of the developer carrying member, and the potential difference between the supporting and developer carrying members is maintained to prevent sticking and fusing, while increasing the charge quantity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the blade bias is increased to increase developer charge quantity and suppress fogging, then fogging is reduced, but developer regulation becomes defective causing density unevenness and background fogging
Solution Approach 1:
The regulating member is divided into two distinct functional regions: a first region for developer regulation and a second region for developer charging. This segmentation allows each region to perform its specific function optimally without interfering with the other, resolving the contradiction between regulation precision and charge quantity.
Solution Approach 2:
Different regions of the regulating member are assigned different electrical properties: the first region has a first electrical potential for regulation, while the second region has a second electrical potential for charging. This local differentiation enables simultaneous achievement of precise regulation and sufficient charging to suppress fogging.
2Reliability
If the blade bias is increased to prevent developer sticking and fusing to the regulating member, then image defects like vertical streaks are prevented, but developer regulation becomes defective causing density unevenness
Solution Approach 1:
The regulating member is divided into two distinct functional regions: a first region for developer regulation and a second region for developer charging. This segmentation allows each region to perform its specific function optimally without interfering with the other, resolving the contradiction between regulation precision and charge quantity.
Solution Approach 2:
Different regions of the regulating member are assigned different electrical properties: the first region has a first electrical potential for regulation, while the second region has a second electrical potential for charging. This local differentiation enables simultaneous achievement of precise regulation and sufficient charging to suppress fogging.
3Object-affected harmful factors
If the nip width of the regulating member is increased to increase developer charge quantity, then fogging is suppressed, but developer sticking and fusing to the regulating member increases
Solution Approach 1:
The regulating member is divided into two distinct functional regions: a first region for developer regulation and a second region for developer charging. This segmentation allows each region to perform its specific function optimally without interfering with the other, resolving the contradiction between regulation precision and charge quantity.
Solution Approach 2:
Different regions of the regulating member are assigned different electrical properties: the first region has a first electrical potential for regulation, while the second region has a second electrical potential for charging. This local differentiation enables simultaneous achievement of precise regulation and sufficient charging to suppress fogging.
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
Prevents image defects like low density portions and vertical streaks by preventing developer sticking and fusing, while effectively increasing the developer charge quantity to suppress fogging without causing regulation defects.
Implementation Method 1
a potential difference (V1−V2) between the supporting member and the developer carrying member, a polarity of which is the same as a charging polarity of the developer
Implementation Method 2
an electrical force for allowing a developing portion to move a developer in a regular direction based on an electric field formed by the potential difference
Data Source
AI summary
A relation between a first thickness of a resin layer in an upstream portion of a contact nip in which the resin layer that covers a supporting member of a regulating blade makes contact with a developing roller and a second thickness of the resin layer in a downstream portion of the contact nip is set such that the second thickness is smaller than the first thickness. A potential difference having the same polarity as a toner charging polarity toward the supporting member is created between the supporting member and the developing roller.