Developing Apparatus Toner Uniformity via Segmented Conveyance
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Solution Overview
Problem
Conventional developing units in electrophotographic image forming apparatuses experience non-uniform toner conveyance due to twisting and deformation of the toner conveyance shaft, leading to uneven toner distribution and image defects in the longitudinal direction.
Innovation Solution
A developing apparatus with a conveyance shaft and two sheet members, where the second conveying member is positioned upstream of the first conveying member and has a shorter length, with overlapping fixed ends and varying free end distances to enhance toner conveyance uniformity by leveraging elastic restoring forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single flexible sheet member is used to convey toner, then the structure is simple, but the toner conveyance amount becomes non-uniform in the longitudinal direction due to shaft twisting and deformation
Solution Approach 1:
The single flexible sheet member is divided into multiple sheet members (first sheet member and second sheet member) that are arranged in the longitudinal direction. Each sheet member independently conveys toner, which compensates for the twisting and deformation of the conveyance shaft, thereby maintaining uniform toner conveyance across the entire width of the developing chamber.
2Device complexity
If the conveyance shaft is driven from one end only, then the drive mechanism is simple, but the shaft twists and deforms under toner load, causing non-uniform toner distribution
Solution Approach 1:
Multiple sheet members are positioned at different locations along the conveyance shaft, with each sheet member locally supporting and conveying toner. This distributed arrangement reduces the concentrated load on any single section of the shaft, minimizing twisting and deformation while maintaining structural simplicity.
3Area of stationary object
If a longer sheet member is used to cover the entire width, then the toner conveyance coverage is complete, but the sheet member experiences non-uniform flexion and toner distribution
Solution Approach 1:
Instead of using one long sheet member, the conveying surface is segmented into multiple shorter sheet members arranged side by side in the longitudinal direction. Each sheet member has a manageable length that reduces flexion variation, while the collective arrangement ensures complete width coverage and uniform toner distribution.
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 configuration ensures more uniform toner distribution across the developing chamber, reducing image defects by maintaining consistent toner conveyance amounts in the longitudinal direction.
Implementation Method 1
the developer accommodated in the developer accommodating chamber is conveyed to the developing chamber with restoring force generated by elastic deformation of the flexible sheet member
Data Source
AI summary
A second conveying member is disposed upstream of a first conveying member in a rotation direction of a conveyance shaft in a state in which a fixed end of the second conveying member and a fixed end of the first conveying member overlap each other. In a first position, a second position, and a third position that sequentially distance away from a drive transmission member in an axial direction of the conveyance shaft, a free end of the first conveying member and a free end of the second conveying member sequentially becomes larger as well.