Fixing Belt Tension Control for Image Forming Apparatus
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing fixing devices for toner images on sheets face issues where the movement of the fixing belt in the width direction is limited by components that come into contact with the belt, leading to potential damage from increased force.
Innovation Solution
A configuration where a first unit retains the belt with the fixing roller, a second unit applies tension to the central portion of the belt, and a third unit further applies tension, ensuring the central portion is farther from the ends, reducing belt movement and force distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If components come into contact with end portions of the belt in the width direction to limit movement, then belt movement is restricted, but the belt receives large force and risks damage
Solution Approach 1:
The pressing unit applies pressure locally to the central portion of the belt rather than uniformly across the width. The pressing portion has a width smaller than the belt width and is positioned to contact only the central region, creating localized pressure that prevents snake movement without concentrating excessive force on specific points that could cause damage.
2Stability of the object's composition
If the belt receives uniform tension in the width direction, then movement is limited, but the force distribution may cause damage at critical points
Solution Approach 1:
The pressing unit is divided into a pressing portion that contacts the belt and a non-pressing portion at both ends in the width direction. This segmentation allows the central region to receive pressure for stability while the end regions remain free from excessive force, preventing damage at critical points where the belt might be most vulnerable.
3Stability of the object's composition
If projections are added at ends of tensioning members, then snake prevention is achieved, but device complexity increases
Solution Approach 1:
The tensioning function and the snake prevention function are merged into a single pressing unit structure. The pressing unit simultaneously applies tension to the belt and prevents snake movement through its specific geometry (pressing portion with width smaller than belt width), eliminating the need for separate projection features on tensioning members and simplifying the overall device structure.
Data Source
AI summary
A fixing device includes an endless belt; a pressing unit that is in contact with an outer peripheral surface of the belt and that rotates the belt; a first unit that is provided on an inner peripheral surface of the belt and that retains the belt in contact with the pressing unit; a second unit provided on the inner peripheral surface of the belt and located downstream of the first unit in a rotation direction of the belt, the second unit applying tension to the belt and including a portion that is in contact with a central portion of the belt in a width direction of the belt and that is farther in a direction toward the outer peripheral surface of the belt than both ends of the belt in the width direction of the belt; and a third unit provided on the inner peripheral surface of the belt and located downstream of the second unit in the rotation direction of the belt, the third unit applying tension to the belt and including a portion that is in contact with the central portion of the belt in the width direction of the belt and that is farther in the direction toward the outer peripheral surface of the belt than both ends of the belt in the width direction of the belt.