Developing Apparatus Agitating Members Guide Braking Portion
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Solution Overview
Problem
In electrophotographic developing apparatuses, maintaining a suitable developer amount and preventing image defects such as toner scattering and fogging during low printing rates is challenging due to uneven developer distribution and inadequate agitation, leading to image quality deterioration.
Innovation Solution
A developing apparatus with a housing featuring a developer supplying and recovering portion and an agitating portion, including a conveying member, a first agitating member, and a second agitating member, along with a projection-shaped guide and a braking portion, to ensure balanced circulation and proper developer distribution, preventing excessive discharge and ensuring sufficient agitation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the replenished toner is conveyed without sufficient agitation, then the conveying time is reduced and high speed response is improved, but image deterioration such as toner scattering and fogging occurs
Solution Approach 1:
The developing device is divided into multiple sections: a replenishing section for adding toner, a first agitating and conveying section for initial mixing and charging, and a second agitating section for further agitation before the developing roller. This segmentation ensures that toner receives sufficient agitation at each stage without requiring excessive conveying time, thus maintaining image quality while enabling high-speed operation.
2Reliability
If a plurality of agitating members are provided to prevent toner scattering and fogging, then image quality is improved, but the circulation balance of developer becomes complex and difficult to control
Solution Approach 1:
Different agitating members are positioned at specific locations within the developing device to address local requirements. The first agitating and conveying section is positioned where replenished toner first enters, providing initial charging and mixing. The second agitating section is positioned closer to the developing roller to ensure final agitation quality. This localized arrangement simplifies the overall circulation balance while maintaining image quality.
3Manufacturing precision
If the toner diameter is reduced to 6 μm or less for high image quality, then resolution is improved, but fluidity deteriorates and aggregation and embedding are significantly caused by load
Solution Approach 1:
A carrier is introduced as an intermediary substance in the two-component development system. The carrier particles are larger and more robust, handling the mechanical loads of agitation and conveying. The fine toner particles (6 μm or less) coat the carrier particles, benefiting from the carrier's mechanical strength while maintaining high image quality. This intermediary approach prevents aggregation and embedding of the fine toner particles.
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 maintains a suitable developer amount, prevents image defects, and ensures high-quality images even at low printing rates by effectively agitating and distributing the developer, reducing toner scattering and fogging.
Implementation Method 1
a first agitating member arranged in the developer agitating portion so as to extend along a direction of a rotating axis of the conveying member, conveying the developer in an inverse direction to the conveying direction by the conveying member while agitating
Implementation Method 2
conveying the developer in an inverse direction to the conveying direction by the conveying member while agitating
Implementation Method 3
a conveying member arranged in the developer supplying and recovering portion in such a manner as to extend along a direction of a rotating axis of the developer carrier, supplying the developer to the developer carrier, conveying the developer in a longitudinal direction
Implementation Method 4
a developer carrier provided on an opposite side to the developer agitating portion in the developer supplying and recovering portion, and attaching the toner to a photo conductor so as to develop an electrostatic latent image
Data Source
AI summary
A housing of a developing apparatus is provided with a conveying member in a developer supplying and recovering portion, and with two agitating members rotating from the below to the above in portions opposed to each other in a developer agitating portion. A guide is provided in an inner bottom surface of the housing between two agitating members. A braking portion suppressing a discharge of a developer is provided in a downstream side of the developer agitating portion in a developer conveying direction of the second agitating member, and a discharge portion is provided in a downstream side of a disc of the braking portion.