Developing Device Ducts for Floating Toner Suction
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Solution Overview
Problem
In electrophotographic image forming apparatuses, floating toner can leak outside the developing device, leading to smeared interiors and deteriorated printing quality, as existing suction devices struggle to effectively capture toner in the narrow downstream space of the photoconductor rotation direction.
Innovation Solution
The developing device incorporates a housing with a downstream cover portion featuring facing openings and concave portions, bonded with a film member to form ducts that communicate with a suction device, allowing efficient suction of floating toner from the downstream side despite the narrow space, using a combination of facing openings and concave paths to direct toner into a side opening for collection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a suction device is provided near the developing roller on the upstream side, then floating toner can be sucked, but the suction effectiveness is insufficient in the narrow downstream space
Solution Approach 1:
The patent introduces a new spatial dimension by creating ducts that extend in the rotation axis direction of the developing roller, perpendicular to the conventional upstream/downstream arrangement. This allows the suction device to access floating toner from multiple directions including the downstream side, effectively utilizing the narrow downstream space that was previously inaccessible.
Solution Approach 2:
The housing is divided into multiple sections with facing openings at different locations along the rotation axis direction. Each opening connects to separate ducts that lead to the suction device, allowing segmented suction paths that can be independently optimized for different regions of the developing device.
2Volume of moving object
If the housing is made compact to reduce size, then the device is more compact, but the downstream space becomes too narrow for effective toner suction
Solution Approach 1:
The ducts are nested within the housing structure, with concave portions formed directly in the housing walls and ducts integrated into the housing geometry. This nesting allows the suction passages to be embedded within the compact housing volume without requiring additional external space, maintaining compactness while providing effective suction paths.
Solution Approach 2:
By utilizing the rotation axis direction (a dimension perpendicular to the conventional flow direction), the patent creates suction passages that efficiently use the available narrow downstream space without requiring increased housing volume in the traditional longitudinal direction.
3Reliability
If facing openings are provided at multiple locations, then toner can be suctioned from multiple positions, but the structure becomes more complex
Solution Approach 1:
Multiple facing openings and their associated ducts are merged into a single integrated housing structure. The concave portions and ducts are formed as unified features of the housing, eliminating the need for separate components and reducing overall structural complexity while maintaining multiple suction access points.
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 captures floating toner, preventing it from escaping and maintaining image quality by ensuring efficient suction even in the constrained downstream space of the photoconductor rotation direction, thus enhancing the operational reliability of the image forming apparatus.
Implementation Method 1
a suction device configured to suck air
Data Source
AI summary
A developing device includes a developing roller, a housing, and a film member. A side opening provided in the housing communicates with a suction device at an end in a rotation axis direction of the developing roller. A downstream cover portion of the housing covers the developing roller from a downstream side in a rotation direction of the image carrying member. Concave portions of the downstream cover portion and a portion of a film member bonded to the downstream cover portion form ducts that communicate from openings facing the image carrying member to the side opening.