Helical Reverse-Transport Blade for Uniform Developer Distribution
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Solution Overview
Problem
In image forming apparatuses, the density of the toner image developed in certain regions of the development region can be lower than in other regions due to uneven developer distribution, leading to inconsistent image quality, particularly as the length of the development region increases.
Innovation Solution
A developing device with a helical forward-transport blade and a helical reverse-transport blade on a rotating shaft, where the reverse-transport blade extends upstream to prevent developer accumulation and ensure consistent distribution, maintaining the density of the toner image across the development region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the forward-transport blade reaches the downstream end of the first transport path, then the developer transport capability is improved, but the developer distribution uniformity deteriorates causing density fluctuations in the downstream region
Solution Approach 1:
The transport blade is segmented into two distinct functional sections: a forward-transport blade section that extends from the upstream end to the connection portion, and a reverse-transport blade section that extends from the connection portion upstream. This segmentation allows each section to perform its specific function - the forward section transports developer downstream while the reverse section prevents accumulation at the connection portion, thereby maintaining uniform distribution without sacrificing transport capability.
2Area of stationary object
If the development region length is increased to handle larger image areas, then the image area coverage is improved, but the developer distribution uniformity deteriorates leading to density variations
Solution Approach 1:
The reverse-transport blade is specifically positioned at the connection portion between the first and second transport paths, creating a localized control mechanism. This local quality approach addresses the specific problem area where developer accumulation occurs due to the connection geometry, without affecting the overall transport efficiency in other regions. The reverse blade's localized action ensures uniform distribution across the entire extended development region.
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 solution effectively suppresses density fluctuations in the toner image, maintaining consistent image quality by ensuring adequate developer supply to all regions of the development area, thereby preventing decreases in image density.
Implementation Method 1
a helical reverse-transport blade that reverse-transports the developer in a reverse direction reverse to the first transport direction; the reverse-transport blade is provided on at least a portion of part of the rotating shaft adjacent to the first connection portion
Data Source
AI summary
A developing device including a first transport path in which the developer to be supplied to the development-region passing body is transported at least in a first transport direction; a second transport path in which the developer to be sent to the first transport path is transported at least in a second transport direction; and a first connection portion through which a portion of the first transport path positioned short of a first-transport-direction-downstream end of the first transport path and a portion of the second transport path positioned short of a second transport-direction-upstream end of the second transport path are connected to one another. A first transport member in the first transport path has a helical reverse-transport blade that reverse-transports the developer in a reverse direction reverse to the first transport provided adjacent to the first connection portion.