Developing Apparatus Toner Supply Reduction Walls
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Solution Overview
Problem
Existing image forming apparatuses face issues with toner supply management, leading to uneven toner distribution and fogging due to rapid entry of additional toner, which causes vertical stripes and edge portion fogging in images.
Innovation Solution
The implementation of downstream and upstream reduction walls or paddles in the developing apparatus to control toner accumulation and distribution, ensuring stable toner supply and mixing, thereby reducing fogging and improving image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If additional toner is supplied rapidly into the development housing, then toner supply efficiency is improved, but toner distribution becomes uneven causing vertical stripes and fogging
Solution Approach 1:
An accumulation portion is introduced as an intermediary chamber between the toner supply inlet and the main development housing. This accumulation portion temporarily stores additional toner before it enters the development housing, acting as a buffer that mediates between rapid toner supply and uniform distribution requirements. The accumulation portion receives toner from the toner supply inlet and gradually releases it into the development housing through controlled interaction with the agitating screw, preventing direct rapid injection that causes distribution problems.
Solution Approach 2:
The accumulation portion performs preliminary action by pre-storing and pre-mixing additional toner before it enters the main development housing. The agitating screw in the accumulation portion begins mixing the additional toner with a small amount of development housing toner that enters first, preparing a uniformly mixed toner stream in advance. This preliminary mixing action ensures that when toner is supplied to the development housing, it is already uniformly distributed, preventing vertical stripes and fogging while maintaining efficient supply.
2Quantity of substance
If a conveying capability reduction portion is provided downstream of the toner supply inlet, then toner accumulation is improved for blocking the inlet, but toner distribution upstream becomes unstable
Solution Approach 1:
The conveying screw is segmented into distinct functional zones: an upstream portion with normal conveying capability that maintains stable toner distribution and flow to the development housing, and a downstream portion with reduced conveying capability that creates the accumulation portion for blocking the toner supply inlet. This segmentation allows each zone to perform its specific function independently - the upstream portion ensures stable distribution while the downstream portion enables controlled accumulation, resolving the contradiction between these two requirements.
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 solution stabilizes toner distribution and reduces fogging, resulting in improved image quality with reduced vertical stripes and edge portion fogging, even under varying toner container pressures and toner characteristics.
Implementation Method 1
an agitating screw having helical blades provided around a rotation shaft is mounted. Toner is circulated and conveyed, by the agitating screws, in and between the forward conveying path and the return conveying path.
Implementation Method 2
a conveying capability reduction portion configured to locally reduce conveying capability is provided, downstream of the toner supply inlet, on the downstream side of the agitating screw disposed in the forward conveying path. Due to the conveying capability reduction portion, an accumulation portion for toner is formed, near the toner supply inlet, upstream of the conveying capability reduction portion.
Data Source
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AI summary
A developing apparatus according to one aspect of the present disclosure includes a developing roller, a development housing, a first agitating screw, a toner supply inlet, a downstream-side reduction wall, and an upstream-side reduction wall. The developing roller is driven to rotate in the development housing, and carries toner on the circumferential surface thereof. Toner is circulated and conveyed in a first conveying path and a second conveying path in the development housing. The first agitating screw is disposed in the first conveying path, and conveys toner in a first direction. The downstream-side reduction wall is disposed downstream of the toner supply inlet. Further, the upstream-side reduction wall is disposed upstream of the toner supply inlet. An accumulation portion for toner is formed downstream and upstream of the toner supply inlet due to the downstream-side reduction wall and the upstream-side reduction wall.