Belt Driving Apparatus Steering Control
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Solution Overview
Problem
In image forming apparatuses using the intermediate transfer method, belt deviation control becomes insufficient due to variations in roller accuracy and alignment, leading to deformation such as waving and wrinkling, especially when the driving roller functions as the steering roller, and high transfer bias voltage causes rubber exudation, further compromising the belt's restraining force.
Innovation Solution
A belt driving apparatus with a steering roller and a supporting roller, where the relationship between dynamic friction coefficients and external forces is managed to ensure the steering roller's alignment can effectively control the belt's position, using a tension roller to apply tension and load members to apply external forces, satisfying the condition μ1(2T sin(θ1/2)+f1)<μ2(2T sin(θ2/2)+f2) to maintain belt deviation control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the driving roller functions as the steering roller with high friction coefficient to prevent belt slipping, then belt deviation control is improved, but the restraining force on the belt becomes excessive causing deformation such as waving and wrinkling
Solution Approach 1:
The patent divides the roller system into distinct driving roller and steering roller components. The driving roller provides friction-driven motion while the steering roller (with lower friction coefficient) provides alignment control. This segmentation allows independent optimization of each roller's function, preventing the belt deformation that occurs when a single roller must simultaneously provide both driving force and steering control.
Solution Approach 2:
The patent applies different friction coefficients to different rollers based on their specific functions. The driving roller has a higher friction coefficient optimized for preventing belt slipping, while the steering roller has a lower friction coefficient optimized for belt alignment. This local differentiation of properties allows each component to perform its function optimally without causing adverse effects on the belt.
2Ease of manufacture
If a cleaning blade is provided to retrieve residual toners on the intermediate transfer belt, then cleaning performance is improved, but the pressure applied to the steering roller increases beyond the corrective capability
Solution Approach 1:
The patent separates the cleaning function from the steering function by providing a dedicated cleaning blade that contacts the intermediate transfer belt independently of the steering roller. This segmentation allows the cleaning blade to apply necessary pressure for toner removal without compromising the steering roller's ability to maintain belt alignment, as the cleaning pressure is applied at a different location and does not directly affect the steering roller's corrective capability.
3Productivity
If high transfer bias voltage is applied to the inner secondary transfer roller, then transfer performance is improved, but rubber exudation occurs increasing the friction coefficient and compromising belt restraining force
Solution Approach 1:
The patent introduces a coating layer as an intermediary between the inner secondary transfer roller and the intermediate transfer belt. This coating layer acts as a barrier that prevents rubber exudation from reaching the belt surface, thereby maintaining consistent friction characteristics and belt restraining force even when high transfer bias voltage is applied. The coating layer mediates the interaction between the roller and belt, isolating the belt from the harmful effects of rubber exudation.
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 ensures effective belt deviation control, preventing deformation and malfunction by maintaining a sufficient steering capability, even when the inner secondary transfer roller is deformed, and stabilizes the belt's operation without being affected by external forces.
Implementation Method 1
a tension roller that applies a tensional force on the endless belt supported by the supporting roller and the steering roller
Implementation Method 2
a first load member that applies a first external force on the supporting roller through the endless belt; a second load member that applies a second external force on the steering roller through the endless belt
Data Source
AI summary
A belt driving apparatus is configured so as to satisfy a relationship μ1(2T sin(θ1/2)+f1)<μ2(2T sin(θ2/2)+f2), wherein μ1 is a dynamic friction coefficient between the supporting roller and the endless belt, μ2 is a dynamic friction coefficient between the steering roller and the endless belt, θ1 is a winding angle of the endless belt with respect to the supporting roller, θ2 is a winding angle of the endless belt with respect to the steering roller, f1 is the first external force applied to the supporting roller through the endless belt, f2 is the second external force applied to the steering roller through the endless, and T is a tension force applied to the endless belt by the tension roller.