Brush Transfer Device Upstream Contact Sequence
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Solution Overview
Problem
Image forming apparatuses using electrophotography with brush-shaped transfer devices experience streak-like image defects due to conductive fiber threads protruding upstream, causing electric discharging, and potential displacement or detachment from the holding member during contact with the intermediate transfer belt.
Innovation Solution
The image forming apparatus design includes a brush-shaped transfer device with conductive fiber threads where the upstream side of the fiber member touches the transfer belt before the downstream side, and the holding surface is inclined to increase the distance from the downstream side to the upstream side, preventing protrusion and ensuring stable contact, thus minimizing streak-like defects and fiber displacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conductive fiber threads are made to contact the transfer belt using elasticity, then transfer uniformity is improved, but fiber threads may protrude upstream and cause discharging
Solution Approach 1:
The upstream side of the fiber member is configured to contact the transfer belt before the downstream side, in advance of the main transfer operation. This preliminary contact arrangement prevents fiber protrusion into the photoconductor- transfer belt contact area, eliminating the harmful discharging effect while maintaining transfer uniformity through the elastic contact of fibers.
Solution Approach 2:
The holding surface is designed with an inclination angle relative to the transfer belt, creating a three-dimensional angled contact configuration. This dimensional change ensures that fibers contact the belt in a controlled sequence from upstream to downstream, preventing upstream protrusion while maintaining effective transfer contact.
2Force
If conductive fiber threads receive force in the movement direction during contact, then transfer pressure is improved, but fibers may come out or be displaced from the holding member
Solution Approach 1:
The holding surface is designed with an asymmetric inclination angle rather than a symmetric perpendicular arrangement. This asymmetric configuration allows the fibers to receive transfer pressure forces while the inclined geometry naturally guides these forces into the holding member, preventing fiber displacement or detachment while maintaining effective transfer pressure.
Solution Approach 2:
The inclined holding surface acts as an intermediary structure that mediates between the transfer pressure forces and the fiber holding function. It converts the force in the movement direction into components that are resolved by the inclination geometry, preventing direct forces that would cause fiber displacement while maintaining necessary contact pressure.
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 reduces streak-like image defects and prevents conductive fiber threads from coming out or being displaced from the holding member, ensuring consistent and high-quality image formation.
Implementation Method 1
multiple conductive fiber threads are brought into contact with a transfer belt
Implementation Method 2
The metal holder is fixed and the conductive fiber threads constituting the transfer device come into contact with the back surface of the intermediate transfer belt using their elasticity
Data Source
AI summary
A fiber member and a transfer belt are movable into contact with or away from each other. In an initial contact state in which an image carrying member and the transfer belt are separated and the transfer belt and the fiber member start touching, an upstream side of the fiber member in the movement direction of the transfer belt touches the transfer belt before a downstream side of the fiber member touches the belt. In a contact state in which the image carrying member and the transfer belt are in contact and the transfer belt and the transfer device are in contact, a holding surface is inclined with respect to an opposing portion of an inner peripheral surface of the transfer belt in such a manner that a distance between the holding surface and the opposing portion increases from the downstream side to the upstream side in the movement direction.