Sheet Heating Element Pressure Position for Uniform Fusing
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Solution Overview
Problem
The existing fusing apparatuses face issues with uniform heating and thermal expansion, leading to temperature unevenness and potential substrate damage due to the pressure position of the sheet heating element, particularly when pressed against a rigid member, which affects power saving and warm-up time.
Innovation Solution
A fusing apparatus with a sheet heating element that includes parallel resistance heating layers on a substrate, where the pressure member presses the sheet heating element against a rigid member at positions other than the conduction portions, preventing thermal expansion-induced gaps and ensuring uniform heating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sheet heating element is pressed against the rigid member at positions where conduction portions are formed, then good contact is achieved, but thermal expansion causes gaps to form and heating becomes non-uniform
Solution Approach 1:
An elastic member is introduced as an intermediary between the pressure member and the sheet heating element. This elastic member deforms elastically under pressure to maintain consistent contact between the sheet heating element and the rigid member, compensating for thermal expansion gaps that form during heating operation.
Solution Approach 2:
The position of the pressure member is changed from pressing at conduction portions to pressing at intermediate portions between conduction portions. This parameter change in pressure application location prevents direct compression of the conduction portions, allowing uniform heat distribution while maintaining contact stability through elastic deformation.
2Productivity
If the sheet heating element is pressed against the rigid member to ensure good contact, then heating efficiency improves, but the substrate may be damaged due to thermal expansion
Solution Approach 1:
The elastic member serves as a cushioning element that is pre-positioned between the pressure member and the sheet heating element. When thermal expansion occurs during heating, the elastic member absorbs the expansion stress through its elastic deformation, preventing damage to the substrate while maintaining heating efficiency.
Solution Approach 2:
The pressing position parameter is changed from conduction portions to intermediate portions, and the pressure application method is changed to use elastic deformation rather than direct rigid pressing. This allows maintaining heating efficiency while avoiding substrate damage from thermal expansion.
3Reliability
If the sheet heating element uses a rigid structure for stable contact, then contact reliability improves, but thermal expansion causes non-uniform heating
Solution Approach 1:
Different parts of the sheet heating element are given different properties: the substrate maintains a rigid structure for stable contact, while the heating layers are designed to distribute heat uniformly. The pressure is applied at intermediate portions rather than conduction portions, creating local quality differences in how different areas respond to thermal expansion.
Solution Approach 2:
The elastic member acts as a mediator that allows the rigid sheet heating element to maintain contact reliability while compensating for thermal expansion. The elastic member deforms to absorb expansion stresses, preventing non-uniform heating while maintaining stable contact between the rigid heating element and the rigid member.
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 achieves stable and robust uniform heating, prevents substrate damage, and enhances power saving while shortening warm-up time by avoiding thermal expansion issues.
Implementation Method 1
a plurality of parallel resistance heating layers which are formed on a surface of the substrate along a longitudinal direction of the substrate
Implementation Method 2
a rigid member for conducting the heat to the endless belt as a heat-conductor, the rigid member being arranged to contact with the sheet heating element and the endless belt respectively
Implementation Method 3
an appropriate position for pressing the sheet heating element is selected, whereby a uniform heating and a robust and stable configuration can be realized
Data Source
AI summary
A fusing apparatus includes a heating element generating heat to fix a toner image onto a sheet; a rigid member conducting the heat to an endless belt and arranged to contact the heating element and the endless belt; and a pressure member pressing the heating element against the rigid member. The endless belt contacts the sheet, the heating element includes an elongated substrate extending in a widthwise direction of the endless belt, plural resistance heating layers formed on a surface of the substrate along a longitudinal direction thereof and arranged parallel to one another, and at least one conduction portion formed in at least one place of an intermediate region between one end and another of each resistance heating layer to connect the different resistance heating layers, and the pressure member presses the heating element against the rigid member at a position other than where the conduction portion is formed.