Fixing Device Heater with Localized Resistors for Image Forming
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Solution Overview
Problem
Conventional fixing devices in image forming apparatuses face inefficiencies in heat transfer to the fixing belt, leading to uneven heat distribution and reduced effectiveness in fixing images onto paper.
Innovation Solution
The proposed fixing device incorporates a heater with a positive temperature coefficient, attached to a fixture that contacts the inner surface of the fixing belt. This configuration includes an insulating layer between the heating surface and the fixing belt, along with electrodes and a conduction path for efficient power supply and heat distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If electrodes are provided on side surfaces of heat generation resistors with entire area heating, then heat diffusion is easy, but heat transfer efficiency to fixing belt deteriorates
Solution Approach 1:
The heating surface is designed with a localized heating structure where heat generation resistors are arranged only in specific regions rather than covering the entire area. This creates different thermal characteristics in different zones: the heating surface efficiently transfers heat to the fixing belt where needed, while non-heating regions allow heat diffusion to occur. This local differentiation resolves the contradiction by enabling both efficient heat transfer (where heating elements are present) and heat diffusion (in non-heating regions), achieving optimal thermal management.
2Use of energy by moving object
If heater is in direct contact with fixing belt, then heat transfer is efficient, but heat distribution uniformity deteriorates
Solution Approach 1:
The heating surface incorporates localized heating regions with heat generation resistors positioned at specific locations rather than uniform distribution. This allows different parts of the heating surface to have different thermal characteristics, enabling efficient heat transfer at contact points while maintaining overall heat distribution uniformity across the fixing belt through strategic placement of heating elements.
Solution Approach 2:
The heating surface acts as an intermediary between the heat generation resistors and the fixing belt. It provides a controlled thermal interface that facilitates efficient heat transfer to the fixing belt while the insulating layer and strategic resistor placement prevent excessive heat concentration, thereby maintaining heat distribution uniformity.
3Area of stationary object
If heater covers entire area between electrodes, then heat coverage is complete, but heat transfer efficiency to fixing belt deteriorates
Solution Approach 1:
Instead of distributing heating elements across the entire area between electrodes, the invention concentrates heat generation resistors in specific localized regions on the heating surface. This creates focused heating zones that efficiently transfer heat to the fixing belt where it is most needed, rather than diffusing heat across the entire area. The heating surface area is optimized to provide sufficient heat coverage while maintaining high transfer efficiency through strategic resistor placement.
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
The design achieves efficient heat transfer to the fixing belt, ensuring consistent and effective image fixation onto paper, even with varying paper sizes and types.
Implementation Method 1
The heater has a positive temperature coefficient and generates heat through resistive heating
Implementation Method 2
The heating surface and the inner surface of the fixing belt have an insulating layer therebetween, allowing efficient heat transfer to the fixing belt
Implementation Method 3
The heating surface and the inner surface of the fixing belt have an insulating layer therebetween
Implementation Method 4
The insulating layer has, on a side thereof facing toward the heating surface, power supply electrodes that supply electric power to the heater
Data Source
AI summary
A fixing device includes a fixing pad and a heater. The fixing pad is in contact with an inner surface of a fixing belt and is located opposite a pressure roller to form a nip between the fixture and the pressure applicator where the pressure is applied to the paper. The heater is attached to the fixing pad and has a positive temperature coefficient. The heater has a heating surface that faces toward the nip and generates heat. The heating surface and the inner surface of the fixing belt have an insulating layer (substrate) therebetween.