Heater Positioner for Thermal Expansion Control
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Solution Overview
Problem
The existing heating devices in image forming apparatuses face issues due to thermal expansion and contraction of the base, which cause electrodes to move and slide within connectors, leading to abrasion and potential power supply disruptions.
Innovation Solution
The proposed heating device includes a positioner that positions the heater closer to the electrodes than the center of the base, reducing the variation in electrode position due to thermal expansion and contraction, and thereby minimizing abrasion at the contact points.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the heater includes a resistance heat generator on a long base made of ceramic or the like, then the heating function is improved, but the electrode position variation due to thermal expansion and contraction increases
Solution Approach 1:
The patent changes the material parameter of the base from ceramic to metal, which has different thermal expansion characteristics. This parameter change allows the base to maintain structural integrity while reducing electrode position variation during thermal cycles, thus improving reliability without sacrificing heating function
Solution Approach 2:
The patent employs composite material construction where a metal base supports the resistance heat generator. The metal base provides dimensional stability under thermal stress while the resistance heat generator maintains heating capability, creating a composite structure that resolves the contradiction between heating function and contact stability
2Speed
If the base expands and contracts due to thermal expansion and contraction, then the heating response is improved, but the electrode slides in the connector causing abrasion
Solution Approach 1:
The patent modifies the thermal expansion parameter by changing the base material from ceramic to metal. This allows the base to expand and contract in a controlled manner that maintains electrode alignment within the connector, enabling fast heating response while minimizing abrasion through optimized material properties
3Adaptability or versatility
If the electrode repeatedly slides in the connector, then the thermal expansion and contraction are accommodated, but the contact portion experiences abrasion preventing satisfactory power supply
Solution Approach 1:
The patent changes the material parameter of the base to metal, which provides controlled thermal expansion characteristics. This allows the system to accommodate thermal expansion and contraction while maintaining electrode position stability in the connector, ensuring reliable power supply without excessive abrasion
Solution Approach 2:
The composite structure of metal base with resistance heat generator creates a system where the metal base absorbs thermal stress through controlled expansion, while the electrode-connector interface maintains stable electrical contact, resolving the contradiction between thermal adaptability and power supply reliability
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 effectively reduces the variations in electrode positions caused by thermal expansion and contraction, maintaining a stable contact between the electrodes and the connector, thus enhancing the reliability and longevity of the heating device.
Implementation Method 1
when the resistance heat generator generates heat to heat the base
Implementation Method 2
the base expands due to thermal expansion and contracts due to a subsequent decrease in temperature
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
A heating device (9) includes a heater (22), a holder (23) configured to hold the heater (22), a positioner (35, 57) configured to position the heater (22) with respect to the holder (23) in a longitudinal direction of the heater (22), a connector (70) including a contact portion (72a) configured to contact an electrode (61) of the heater (22). The heater (22) includes a long base (50), a plurality of heat generators (60) disposed on the base (50), three or more electrodes (61) disposed on the base (50) and electrically connected to the heat generators (60). The positioner (35, 57) is closer to the electrodes (61) than a center position (M) of the base (50) in a longitudinal direction of the base (50).