Developer Circulation Auger Segmentation for Fluidity
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Solution Overview
Problem
Existing development devices for electrophotographic image forming apparatuses face challenges in maintaining developer fluidity due to rapid pressure rise and shear forces, leading to decreased image density and inadequate developer supply to the photoconductive drum.
Innovation Solution
The development device incorporates a circulation type design with first and second developer conveying paths and spiral members, featuring end blades and circumferential agitating plates to reduce stress and improve developer conveyance efficiency, ensuring smooth circulation and sufficient developer supply to the photoconductive drum.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the developer is conveyed rapidly through the auger screw to meet the demand for faster operation, then the productivity is improved, but the pressure rise and shear force increase causing developer fluidity to decrease
Solution Approach 1:
The developer conveying path is divided into multiple sections with partition walls, and the auger screw is segmented into multiple stages. This segmentation allows the developer to be conveyed in smaller portions, reducing the pressure rise and shear force in each section while maintaining overall conveyance speed.
Solution Approach 2:
A fluidity improver is introduced as an intermediary substance mixed with the developer. This additive reduces the internal friction and shear force between developer particles, allowing rapid conveyance without loss of fluidity, thus resolving the contradiction between productivity and reliability.
2Productivity
If the developer is subjected to rapid pressure to enhance conveyance efficiency, then the productivity is improved, but the stress on the developer increases causing fluidity improver to be buried and fluidity to decrease
Solution Approach 1:
The fluidity improver is mixed with the developer beforehand to form a uniform suspension. This pre-mixing ensures that the fluidity improver is distributed throughout the developer, providing continuous cushioning against stress during conveyance and preventing burial under pressure.
Solution Approach 2:
The auger screw rotation speed and conveying pressure are dynamically adjusted during operation. The system maintains optimal conveyance efficiency while preventing excessive stress on the developer by modulating operational parameters in real-time.
3Productivity
If the developer is circulated quickly to meet high-speed operation demands, then the productivity is improved, but the developer supply to the photoconductive drum becomes insufficient
Solution Approach 1:
The developer circulation system is designed to maintain continuous and uniform flow of developer from the auger screw to the photoconductive drum. The segmented conveying path and controlled pressure ensure uninterrupted supply, preventing depletion while maintaining high-speed operation.
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 design effectively reduces stress on the developer, enhances fluidity, and ensures a sufficient amount of developer is supplied to the photoconductive drum, resulting in improved image density and printing quality.
Implementation Method 1
a spiral blade (112a, 113a) that is fixed to a circumferential surface of the rotary shaft
Implementation Method 2
an end blade that is provided at one end of the rotary shaft, the end blade includes: a spiral blade portion that is fixed to the circumferential surface of the rotary shaft; and a circumferential agitating plate portion that is fixed to a circumferential portion of the spiral blade portion
Implementation Method 3
The electrified toner is supplied onto a surface of a development roller. The toner is moved by an electrostatic attraction from the development roller to an electrostatic latent image formed on a surface of a photosensitive drum
Data Source
AI summary
A development device mounted on an electrophotographic image forming apparatus including a photoconductive drum in which an electrostatic latent image is formed on a surface thereof, the development device comprising: a developer tank; a development roller that is provided in the developer tank; first and second developer conveying paths; and first and second developer conveying spiral members that conveying the developer in the circulating manner in the first and second developer conveying paths, wherein at least one of the first and second developer conveying spiral members further includes an end blade that is provided at one end of the rotary shaft, the end blade includes: a spiral blade portion that is fixed to the circumferential surface of the rotary shaft; and a circumferential agitating plate portion that is fixed to a circumferential portion of the spiral blade portion.