Developer Regulating Member Protrusion for Edge Soiling in Electrophotography
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Solution Overview
Problem
The existing developing apparatuses for electrophotographic image forming experience soiling issues at the edge regions of electrophotographic images, particularly in high-temperature and high-humidity environments, due to inconsistent toner layer thickness and reduced triboelectricity, leading to toner scattering and adhesion.
Innovation Solution
A process cartridge and electrophotographic image forming apparatus design featuring a developer bearing roller with a protruding portion that extends over the entire contact region, where the protrusion length in the developing region is constant and larger than at the end portions, ensuring a stable developer layer thickness and frictional charge even outside the developing region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the developer layer thickness is reduced to prevent toner scattering, then toner scattering is suppressed, but the triboelectric charge is insufficient leading to soiling at image edges
Solution Approach 1:
The patent applies local quality by creating different developer layer thicknesses at different locations: the central developing region has a thinner developer layer to prevent scattering, while the end portions have a thicker developer layer to maintain triboelectric charge and prevent soiling. This spatial variation in layer thickness resolves the contradiction between preventing scattering and maintaining sufficient charge.
2Object-generated harmful factors
If the developer layer thickness is increased to maintain triboelectric charge, then triboelectric charge is sufficient, but toner scattering and falling occurs at end portions
Solution Approach 1:
The patent implements local quality by varying the developer layer thickness across different regions of the developer bearing member. The end portions have increased thickness to generate sufficient triboelectric charge, while the central region maintains reduced thickness to prevent toner scattering during development.
3Manufacturing precision
If the elastic regulating blade is positioned to cover the entire developer bearing region, then developer layer regulation is improved, but soiling occurs at image edge regions in high-temperature and high-humidity environments
Solution Approach 1:
The patent applies local quality by extending the elastic regulating blade beyond the developing region to cover the end portions of the developer bearing region. This ensures consistent developer layer thickness control across the entire contact region, preventing soiling at image edges even in high-temperature and high-humidity 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
This configuration stabilizes the developer layer thickness and triboelectricity, significantly reducing soiling and adhesion issues at the image edges, even in challenging environmental conditions, resulting in high-quality electrophotographic images.
Implementation Method 1
a developer bearing roller 32...a developer regulating member 11...the developer regulating member 11 and the developer bearing roller 32 form a contact region
Implementation Method 2
the developer regulating member 11 and the developer bearing roller 32 are pressed against each other
Implementation Method 3
stabilizing the layer thickness of a developer layer 322 on a developer bearing roller 32 and stabilizing triboelectricity of the developer 321
Data Source
AI summary
A process cartridge includes an electrophotographic photosensitive drum, a developer bearing roller, and a developer regulating member, the developer regulating member and the developer bearing roller constituting a contact region, the contact region having a width larger than the width of the developing region in the direction of the axis of the developer bearing roller and extending in the circumferential direction of the developer bearing roller, the developer regulating member having a protruding portion that protrudes over the entire width of the contact region from the end portion on the upstream side of the contact region toward the upstream side in the rotational direction of the roller, and the length of the protruding portion in a region corresponding to the developing region being substantially constant and larger than the length of the protruding portion at the location corresponding to the end portion in the width direction of the contact region.