Movable Heat Shield for Fixing Rotary Body Overheating
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing fixing devices in image forming apparatuses face overheating issues due to non-conveyance spans on the fixing rotary body, which can lead to temperature inconsistencies and reduced performance, especially when handling varying sizes of recording media.
Innovation Solution
A heat shield with noncircular portions is positioned opposite the fixing rotary body to shield it from the heater, and a controller adjusts the heat shield's rotation angle based on the size of the recording medium and detected temperatures to prevent overheating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a heat shield is used to shield the non-conveyance span from the heater, then overheating of the fixing rotary body is prevented, but the heat shield is retained at an identical position during a print job and cannot respond to accidental temperature increases
Solution Approach 1:
The heat shield is made movable along the circumferential direction of the fixing rotary body, transitioning from a static component to a dynamic one. The shield can be positioned at different locations to correspond with different non-conveyance spans, and can move to provide additional shielding when temperature sensors detect overheating conditions during print jobs.
Solution Approach 2:
Temperature sensors detect the temperature of the fixing rotary body and provide feedback to the control unit. When the temperature exceeds a predetermined threshold, the control unit moves the heat shield to an appropriate position to provide additional shielding. This closed-loop feedback system enables the heat shield to respond dynamically to actual temperature conditions.
2Adaptability or versatility
If the heat shield is made movable to different positions, then it can adapt to varying non-conveyance spans, but the device complexity increases
Solution Approach 1:
The mechanical system for moving the heat shield is replaced with a drive belt mechanism that is already present in the fixing device for other purposes. The heat shield is attached to the drive belt, so it moves passively along with the belt's rotation, eliminating the need for separate motors, gears, or actuators dedicated to heat shield positioning.
Solution Approach 2:
The drive belt serves multiple functions: it conveys the heat shield to different positions and simultaneously performs its original function of driving other components of the fixing device. This multi-functionality reduces the overall device complexity by reusing existing mechanical infrastructure rather than adding dedicated mechanisms.
3Temperature
If the heat shield shields the non-conveyance span, then overheating is prevented, but the recording medium may not receive sufficient heat for proper fixing
Solution Approach 1:
The heat shield is designed to provide localized shielding only at the non-conveyance span where overheating occurs, while leaving the conveyance span (where the recording medium passes through) fully exposed to heater radiation. The shield's position and dimensions are carefully controlled to ensure it blocks heat only where needed without interfering with the heating of the recording medium during the fixing process.
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 maintains optimal temperatures across the fixing rotary body, ensuring consistent image fixing quality regardless of recording medium size, thereby preventing overheating and improving device reliability.
Implementation Method 1
a heater disposed opposite and heating the fixing rotary body
Implementation Method 2
a heat shield movably disposed opposite the fixing rotary body... to shield the fixing rotary body from the heater
Implementation Method 3
A temperature detector is disposed opposite at least one of the fixing rotary body and the opposed body to detect a temperature of the at least one of the fixing rotary body and the opposed body
Data Source
AI summary
A fixing device includes a fixing rotary body, a heat shield movably disposed opposite the fixing rotary body, an opposed body contacting the fixing rotary body to form a nip therebetween through which a recording medium is conveyed, and a temperature detector to detect a temperature of at least one of the fixing rotary body and the opposed body. A controller, operatively connected to the heat shield and the temperature detector, determines a rotation angled position to which the heat shield is moved based on a size of the recording medium and the temperature of the at least one of the fixing rotary body and the opposed body detected by the temperature detector.