Developing Apparatus Partition Opening for Developer Circulation
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Solution Overview
Problem
In existing image forming apparatuses, the developer in the developer accommodation chamber tends to be pushed into the development chamber due to its weight and the movement of the stirring member, leading to poor circulation and potential toner leakage, especially when using heavy specific gravity developers or increasing the developer amount, which can impair the functions of the development roller and supply roller.
Innovation Solution
The developer accommodation chamber is positioned at the top in the gravity direction of the development chamber, with a rotating developer bearing member, supply member, and stirring member, and an opening in the partition wall allowing developer movement along the longitudinal direction, ensuring proper circulation by maintaining a shorter distance between the contact region and the upstream end compared to the downstream end.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the developer accommodation chamber is set in a lying posture to prevent developer weight from being imposed, then the harmful effect of dense developer state is reduced, but the apparatus size increases
Solution Approach 1:
The opening in the partition wall is designed with asymmetric dimensions where the width in the rotation direction is smaller than the width in the axial direction. This asymmetric configuration allows the developer to flow smoothly into the development chamber while preventing excessive accumulation, resolving the contradiction between preventing dense developer state and maintaining compact apparatus size.
Solution Approach 2:
The patent introduces a specific spatial configuration by positioning the opening at a particular location on the partition wall with specific dimensional relationships. The opening's width in the rotation direction is made smaller than its width in the axial direction, creating a dimensionally optimized flow path that controls developer movement without requiring a lying posture configuration.
2Reliability
If the developer amount is increased or heavy specific gravity developer is used to improve development quality, then the development performance is enhanced, but the developer becomes more likely to be pushed into the development chamber causing poor circulation
Solution Approach 1:
The partition wall opening is designed with specific local dimensional characteristics where the width in the rotation direction is smaller than the width in the axial direction. This local quality optimization at the opening location allows controlled developer flow that accommodates both heavy specific gravity developers and increased developer amounts while maintaining proper circulation in the development chamber.
3Productivity
If the stirring member moves vigorously to circulate developer in the accommodation chamber, then the developer circulation is improved, but the developer is pushed into the development chamber causing toner leakage
Solution Approach 1:
The asymmetric opening configuration with smaller width in the rotation direction compared to axial direction creates a flow restriction that allows the stirring member to effectively circulate developer in the accommodation chamber while preventing excessive developer from being pushed into the development chamber, thus avoiding toner leakage.
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 configuration effectively circulates the developer, preventing toner leakage and ensuring optimal functioning of the development roller and supply roller, thereby maintaining image quality and apparatus performance.
Implementation Method 1
a stirring member having a shaft, and a sheet member held by the shaft, the sheet member stirring the developer accommodated in the developer accommodation chamber by rotation of the shaft
Implementation Method 2
the developer accommodation chamber is set at a top in a gravity direction of the development chamber
Data Source
AI summary
A developing apparatus comprises a development chamber with a developer bearing member and supply member, and a developer accommodation chamber above it. A stirring member with a sheet member rotates to stir developer. All members rotate along the longitudinal direction, with an opening along the chamber walls. In cross-section, the opening has upstream and downstream ends relative to the stirring member's rotation. At the longitudinal center, the distance from the upstream end to the contact region between the developer bearing member and supply member is shorter than the same distance measured at the longitudinal end.