Belt Position Control for Uniform Image Heating
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Solution Overview
Problem
In image heating apparatuses using a belt member, uneven glossiness occurs due to abrasion marks generated at the edge of the recording material, which are then transferred onto the image surface, affecting image quality. Existing solutions either disperse these marks but increase device size or use a refreshing mode that can lead to differences in contact pressure and surface state, impairing uniformity.
Innovation Solution
An image heating apparatus with a rotatable steering member and a slidable member that adjusts the belt member's surface state by controlling the maximum inclination angle of the steering member during the refreshing mode, ensuring it is set to a value smaller than during image formation, to minimize variations in the belt member's surface state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the range of lateral shift control is enlarged to disperse the abrasion mark, then the abrasion mark is dispersed into a wide range of the belt member, but the movement width of the belt must be ensured and therefore the size of the fixing device is increased
Solution Approach 1:
The patent changes the operational parameters of the belt member by introducing a refreshing mode with different lateral shift control characteristics. Instead of permanently enlarging the lateral shift range, the system dynamically adjusts the lateral shift amount during refreshing operations to disperse abrasion marks effectively while maintaining the original compact device dimensions.
Solution Approach 2:
The patent implements periodic refreshing operations during non-image formation periods. The belt member undergoes lateral shift control alternation between normal image formation mode and refreshing mode, allowing abrasion mark dispersion without continuous lateral shift that would require larger device size. The periodic execution during idle periods achieves dispersion while maintaining compact structure.
2Productivity
If the operation in the refreshing mode is executed in a short time, then the execution time is reduced, but an inclination state of a rotatable steering member during the operation is substantially fixed, and therefore a difference in sliding state is generated at longitudinal end portions of a slidable member, impairing the uniformity of glossiness
Solution Approach 1:
The patent introduces dynamic adjustment of the rotatable steering member's inclination angle during the refreshing operation. Instead of maintaining a fixed inclination state, the system dynamically changes the inclination angle to compensate for differences in sliding state at longitudinal end portions of the slidable member, ensuring uniform glossiness even during short-time execution.
Solution Approach 2:
The patent implements feedback control by monitoring the inclination state of the rotatable steering member and adjusting it during the refreshing operation. The system detects differences in sliding state at longitudinal end portions and provides corrective adjustment to the inclination angle, maintaining uniform glossiness throughout the brief refreshing period.
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 approach reduces variations in the belt member's surface state, preventing differences in glossiness and color tint on the image surface, thereby improving image quality and extending the life of the belt member.
Implementation Method 1
a slidable member 63 that is movable toward and away from a surface of the belt member 51... an execution portion capable of executing an operation in a sliding mode in which the slidable member 63 is contacted to the belt member 51 and is slid on the surface of the belt member 51
Data Source
AI summary
An image heating apparatus includes: a belt for heating in a nip an image formed on a recording material; a rotatable steering member for stretching the belt and for controlling the position of the belt with respect to a widthwise direction by inclination; a slidable member provided so as to be movable toward and away from a surface of the belt; a contact and separation portion for moving the slidable member toward and away from the belt; an execution portion capable of executing an operation in a sliding mode in which the slidable member contacts the belt and is slid on the surface of the belt; and a controller for controlling a maximum inclination angle of the rotatable steering member during execution of the operation in the sliding mode so that the maximum inclination angle is set at a value smaller than that during image formation.