Developing Apparatus Notched Layer Thickness Adjustment Member
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Solution Overview
Problem
Existing two-component developer systems for electrophotographic image forming apparatuses face challenges in preventing toner scattering and achieving sufficient seal performance, especially during thin layer development, leading to issues like fog and density unevenness in the formed images.
Innovation Solution
A developing apparatus with a cylindrical sleeve and magnet roller that carries a two-component developer, featuring a band-shaped layer thickness adjustment member with notches at the ends and a magnetic seal member, optimized to regulate the developer layer thickness and prevent toner scattering by increasing the density of the magnetic brush, thus enhancing seal performance and preventing fog and developer accumulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a magnetic brush seal is formed between the developing roller and magnetic member, then toner scattering is prevented, but sufficient seal performance cannot be achieved during thin layer development
Solution Approach 1:
The invention applies local quality by creating a magnetic brush seal only at the end portions of the developing roller where toner scattering occurs, while maintaining a thin developer layer at the central image forming region. The magnetic members are positioned specifically at the end portions to generate localized magnetic brushes that seal without interfering with the thin layer development process in the center.
Solution Approach 2:
The invention segments the developing roller surface into two functional zones: end portions with magnetic members for sealing, and central portion without magnetic members for thin layer development. This segmentation allows each zone to perform its specific function independently, resolving the contradiction between seal performance and thin layer development.
2Manufacturing precision
If the interval between the regulation blade and developing roller surface is reduced to enable thin layer development, then image quality is improved, but the interval cannot be narrowed at both end portions to prevent toner scattering
Solution Approach 1:
The invention applies local quality by maintaining a small interval between the regulation blade and developing roller surface only at the central image forming region for high-quality thin layer development, while having magnetic members at the end portions that create magnetic brushes to seal and prevent toner scattering regardless of the blade interval.
Solution Approach 2:
The magnetic members act as intermediaries at the end portions, creating magnetic brushes that seal the gap between the developing roller and developer container. This intermediary magnetic brush mechanism prevents toner scattering without requiring the regulation blade interval to be narrowed, thus protecting the thin layer development quality in the central region.
3Manufacturing precision
If the developer layer thickness is reduced for thin layer development, then high image quality is achieved, but toner scattering and fog occur due to insufficient seal performance
Solution Approach 1:
The invention segments the developing roller into end portions with magnetic members for sealing and a central portion for thin layer development. This allows the central region to maintain a thin developer layer for high image quality while the end portions create magnetic brush seals to prevent toner scattering and fog.
Solution Approach 2:
The invention changes the magnetic field parameter by introducing magnetic members at the end portions, which generate strong localized magnetic fields that form dense magnetic brushes. This parameter change enables effective sealing at the ends without requiring changes to the developer layer thickness in the central image forming region, thus preventing fog while maintaining high image quality.
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 scattering and achieves high-quality image formation by ensuring sufficient seal performance and maintaining image density uniformity, even during thin layer development.
Implementation Method 1
a magnet roller including a plurality of magnetic poles fixedly disposed in the sleeve
Implementation Method 2
the carrier carrying the toner is formed in a protruding shape called an ear, and a plurality of ears is gathered to form a magnetic brush
Implementation Method 3
rectangular or substantially rectangular notches open to one end portion side in the width direction being provided at both end portions in a longitudinal direction
Implementation Method 4
When the toner contained in the ears of the magnetic brush moves to the electrostatic latent image on the photoreceptor from the sleeve, the electrostatic latent image is developed
Implementation Method 5
providing a magnetic member at a position facing both end portions of a developing roller, forming a magnetic brush of the developer between the developing roller and the magnetic member, and performing a seal by the magnetic brush
Data Source
AI summary
A developing apparatus including a layer thickness adjustment member configured to regulate a layer thickness of a two-component developer carried on a surface of a developing sleeve of a developing roller is disposed so that one end portion in a width direction faces the surface of the developing sleeve at a predetermined interval. At two end portions in a longitudinal direction of the layer thickness adjustment member, a notch open to the one end side in the width direction is provided. Since an amount of conveyance of the developer locally increases at two end portions of the developing sleeve by providing such a notch in the layer thickness adjustment member, density of an ear of a magnetic brush to be formed increases, and it is possible to exhibit the sufficient seal performance and prevent the toner from being scattered.