Image Forming Fixing Unit with Asymmetric Heat-Balancing Openings
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Solution Overview
Problem
Existing image forming apparatuses experience temperature deviations in the rotational axis direction of the fixing device due to unequal exposure lengths of the rotation shaft, leading to uneven heat distribution and potential fixability issues, without effective solutions that do not increase device size or cost.
Innovation Solution
The image forming apparatus includes a first rotation body with a heater, a second rotation body forming a nip with the first, and a frame body supporting both, where the rotation shaft lengths and opening areas are asymmetrically configured to balance heat distribution, with no openings on one side and larger openings on the other, inhibiting temperature deviations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the rotation shaft is exposed equally from both ends of the pressing roller, then the structure is symmetric and simple, but temperature deviation occurs in the rotational axis direction due to unequal heat transfer to both ends
Solution Approach 1:
The pressing roller is designed with asymmetric shaft exposure where one end extends further than the other end. This asymmetric configuration compensates for the natural heat transfer gradient by exposing the cooler end more to allow greater heat dissipation, thereby balancing the temperature distribution along the rotational axis direction and preventing temperature deviation in the fixing device.
2Temperature
If multiple heating bodies are added to compensate for temperature deviation, then temperature uniformity is improved, but device size and cost increase
Solution Approach 1:
Instead of adding multiple heating bodies, the invention applies local quality by creating asymmetric shaft exposure at specific locations. The unequal exposure lengths at the two ends of the pressing roller provide localized thermal compensation, allowing the single heating body to achieve uniform temperature distribution through strategic geometric design rather than through additional heating components.
3Temperature
If a cooling fan is added to balance temperature, then temperature uniformity is improved, but device size and cost increase
Solution Approach 1:
The pressing roller structure serves its own thermal balancing function through asymmetric shaft exposure. The geometric design allows the roller to self-regulate temperature distribution by providing different exposure lengths at each end, eliminating the need for external cooling fans or active temperature control mechanisms. The structure itself performs the thermal compensation function.
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 maintains uniform temperature distribution across the fixing device, preventing fixability deviations and image defects, while avoiding increases in device size and cost by not requiring additional cooling mechanisms.
Implementation Method 1
a heater (23) disposed in an internal space of the first rotation body (22)
Implementation Method 2
heat is transferred toward an end of the rotation shaft
Implementation Method 3
a total area of openings disposed in a first region of the frame body is a first value, and a total area of openings disposed in a second region of the frame body is a second value larger than the first value
Data Source
AI summary
An image forming apparatus includes: a first and second rotation bodies; a heater disposed in the first rotation body; and a frame body supporting the first and second rotation bodies. A second length is smaller than a first length in a rotational axis direction of the second rotation body, the first length and the second length being a length of a rotation shaft of the second rotation body exposed on a one-end side and an other-end side of the second rotation body, and a second value is larger than a first value, the first value and the second value being a total area of openings disposed in a first region and a second region of the frame body respectively corresponding to the one-end side and the other-end side of the frame body with respect to a center of the frame body.