Heater Positioning Mechanism for Thermal Expansion Control
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Solution Overview
Problem
The existing fixing devices in image forming apparatuses face challenges with positioning accuracy due to thermal expansion and contraction, leading to rattling of the heater within the heater holder, which affects the precise fixing of toner on sheets.
Innovation Solution
A heating device configuration that includes a primary positioner, a secondary positioner, and a tertiary positioner, where the primary and one of the secondary or tertiary positioners are disposed on the same side of the heat generator, allowing for synchronized expansion and contraction, thereby maintaining accurate positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the heater is allowed to expand and contract freely in the longitudinal direction, then the heater can accommodate thermal expansion without restraint, but the heater rattles in the recess and positioning accuracy deteriorates
Solution Approach 1:
The heater holder has different structural characteristics at different locations: one end has a recess for positioning the heater with high accuracy, while the other end has a structure that allows free expansion and contraction. This local differentiation resolves the contradiction by providing restraint where positioning is needed while allowing movement where thermal expansion occurs.
Solution Approach 2:
The heater holder is divided into functionally distinct regions: a positioning region with a recess that restrains the heater for accurate positioning, and an expansion region that allows free movement for thermal accommodation. This segmentation allows each region to perform its specific function without interfering with the other.
2Manufacturing precision
If multiple positioners are disposed on both sides of the heat generator, then the positioning is more balanced, but the complexity of the positioning mechanism increases
Solution Approach 1:
The invention extracts only the necessary positioning function to one side of the heat generator. By placing positioners only on one side, the design achieves adequate positioning accuracy without the complexity of symmetric positioning on both sides, removing unnecessary structural elements.
Solution Approach 2:
The positioning mechanism uses an asymmetric configuration with positioners located only on one side of the heat generator rather than symmetric placement on both sides. This asymmetric design reduces the number of components and simplifies the overall structure while maintaining positioning effectiveness.
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 reduces relative positional shifts and enhances the accuracy of the heating member, holder, and device frame, ensuring precise fixing of toner images on sheets.
Implementation Method 1
The heater includes a heat generator
Implementation Method 2
a difference in thermal expansion coefficient between components may cause a decrease in positioning accuracy of the components
Data Source
AI summary
A heating device includes a heater, a holder, a device frame, a primary positioner, a secondary positioner, and a tertiary positioner. The heater includes a heat generator. The holder holds the heater. The device frame is configured to support the holder. The primary positioner is configured to position the heater and the holder in a longitudinal direction of the heater. The secondary positioner is configured to position the holder and the device frame in the longitudinal direction of the heater. The tertiary positioner is configured to position the device frame and a body of an image forming apparatus in the longitudinal direction of the heater. The primary positioner and one of the secondary positioner and the tertiary positioner are disposed on an identical side defined by a center of the heat generator in the longitudinal direction of the heater.