Fixing Device Thermal Management via Pre-Rotation
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Solution Overview
Problem
The existing fixing devices in image forming apparatuses face issues with deformation and damage due to excessive temperature rise and thermal expansion, particularly when the fixing member has low heat capacity and is heated unevenly, leading to image defects and mechanical damage.
Innovation Solution
A fixing device with a heat source, a rotary fixing member, and a pressing member, where the fixing member is rotated by a predetermined amount after power is halted to prevent excessive temperature rise, using temperature control circuits and independent motor control for the pressing roller and sheet output rollers to manage heat distribution and reduce power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If the fixing member is heated at high temperature for a short period, then energy consumption is reduced and preheating time is shortened, but the fixing member may deform or be damaged due to excessive temperature rise and thermal expansion
Solution Approach 1:
The system performs preliminary actions by rotating the fixing member before halting power to distribute heat evenly and prevent localized overheating. This preliminary heat distribution action prevents deformation and damage while maintaining energy efficiency during rapid heating operations.
Solution Approach 2:
The fixing member undergoes periodic rotation during the heating process to ensure uniform temperature distribution. This periodic mechanical action complements the thermal process, allowing high-temperature heating without causing thermal expansion damage, thus resolving the contradiction between energy efficiency and reliability.
2Speed
If the fixing member is heated unevenly, then heating speed is improved, but image defects occur and the fixing member deforms due to thermal expansion
Solution Approach 1:
The system rotates the fixing member before and during heating to pre-distribute thermal energy evenly across the surface. This preliminary mechanical action ensures that subsequent high-speed heating does not create uneven temperature zones, preventing both image defects and thermal deformation.
Solution Approach 2:
The fixing member transitions from a static heated component to a dynamically rotating one during the heating process. This dynamic approach allows continuous heat distribution, maintaining uniform temperature even at high heating speeds, thereby preserving image quality while achieving rapid heating.
3Loss of time
If the fixing member has low heat capacity (thin roller/belt), then heating time is reduced and energy consumption decreases, but the fixing member is more susceptible to deformation and damage from residual heat
Solution Approach 1:
The system performs preliminary rotation of the fixing member to distribute heat evenly before halting operations. This preliminary action prevents localized heat concentration that would otherwise cause deformation in low heat capacity components, enabling the use of thin, fast-heating structures without compromising structural integrity.
Solution Approach 2:
The system converts the potential harm of residual heat in low heat capacity fixing members into a benefit by using controlled rotation to distribute this heat uniformly. The residual heat that would normally cause deformation is instead used evenly across the surface, preventing thermal damage while maintaining the advantages of low heat capacity design.
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 solution effectively prevents deformation and damage to the fixing member by managing temperature distribution and heat transfer, ensuring stable image formation and extending the lifespan of the fixing device components.
Implementation Method 1
a halogen heater that heats the fixing belt using radiant heat
Implementation Method 2
the fixing belt heats a surface of a recording medium hearing an unfixed toner image
Implementation Method 3
a pressing roller pressed against the fixing member to form a fixing nip therebetween
Data Source
AI summary
A fixing device includes a heat source; a fixing member looped into a generally cylindrical shape to rotate in a circumferential direction thereof and partially heated by the heat source and to heat a surface of a recording medium bearing an unfixed toner image to fix the unfixed toner image thereon in a fixing process; a rotary pressing member disposed facing the fixing member to form a nip therebetween, through which the recording medium is transported in a transport direction; and a rotation driver to rotate one of the fixing member and the pressing member. In a case in which the fixing member is halted for a reason other than the fixing process while power of the fixing device is on, electric power is not supplied to the heat source and the fixing member is rotated by a predetermined amount or more after the fixing member is halted.