Developer Stopper Design for Uniform Image Density
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Solution Overview
Problem
Existing developing devices face issues with uneven image density due to the scooping of low-density, unmixed developer, leading to screw pitch unevenness and mottled unevenness, which affect image quality, particularly in environments with decreased developer fluidity.
Innovation Solution
A developing device with a developer bearer, regulator, and stopper configuration, where the supply path width is between 7% and 10% of the developing roller's circumference, and the stopper width is between 6% and 11%, preventing low-density developer from being scooped and ensuring consistent developer supply, thereby preventing uneven image density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the developer supply passage is configured without proper stopper or with inadequate dimensions, then the developer can freely move to the developer bearer surface, but low-density unmixed developer gets scooped causing screw pitch unevenness and mottled unevenness in the image
Solution Approach 1:
The developer supply passage is segmented into multiple functional regions: a first supply passage for normal developer supply, a second supply passage positioned above a predetermined level, and a stopper region with specific dimensional constraints (width 6-11% of circumference, height 3-8mm). This segmentation allows differentiated control of developer flow to prevent scooping of low-density developer while maintaining adequate supply paths.
Solution Approach 2:
The stopper is designed with specific local dimensional properties (width occupying 6-11% of the developer bearer circumference, height of 3-8mm) to create a localized barrier that selectively prevents scooping of low-density developer while allowing adequate developer supply through the regulated path. The stopper's position at a predetermined level above the bottom of the supply passage creates localized control without affecting the entire passage.
2Quantity of substance
If the stopper width is too small, then the device complexity is reduced, but the supply path becomes insufficient causing inadequate developer supply to the developer bearer
Solution Approach 1:
The stopper is designed with a width that occupies 6-11% of the developer bearer circumference, which is sufficient to prevent scooping of low-density developer but not so large as to block the developer supply path. This partial blocking action maintains adequate developer supply while achieving the prevention function.
Solution Approach 2:
The stopper dimensions are optimized within specific parameter ranges (width: 6-11% of circumference, height: 3-8mm) to balance the conflicting requirements of preventing developer scooping while maintaining adequate supply. The predetermined level positioning and dimensional constraints create optimal flow conditions.
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 effectively prevents screw pitch unevenness and mottled unevenness, maintaining image quality by ensuring sufficient and consistent developer supply, even in high temperature, high humidity environments.
Implementation Method 1
a magnetic field generator and is configured to bear a developer containing toner and magnetic carriers and conveys the developer to a developing area by rotation
Data Source
AI summary
A developing device includes a developer bearer, a developer regulator, a developer supply passage, and a stopper. The developer bearer includes a magnetic field generator and is configured to bear a developer containing toner and magnetic carriers and conveys the developer to a developing area by rotation. A stopper prevents the developer blocked by the developer regulator from moving to a surface of the developer bearer, while securing a supply path for passing the developer in the developer supply passage to the developer bearer between the stopper and an upper end of a side wall of the developer supply passage that is opposite to the developing bearer. A width of the supply path in a direction perpendicular to a direction of a rotation axis of the developer bearer is in a range of 7%-10% of a circumference of an outer diameter of the developing bearer.