Fuser Belt Heat Shield Control for Non-Sheet Region Overheating
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Solution Overview
Problem
Existing image forming apparatuses face issues with excessive temperature rise in the non-sheet-passing regions of the fixing belt, leading to potential damage and reduced productivity, particularly when printing images with varying image area rates and toner overlapping ratios.
Innovation Solution
The introduction of a movable shield that can be controlled to adjust its operating temperature and shielding amount based on image forming conditions, such as image area rate and toner overlapping ratio, to prevent excessive temperature rise in the non-sheet-passing regions of the fixing belt.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the heater continuously heats the fixing belt to maintain fixing temperature, then the fixing function is ensured, but excessive temperature rise occurs in the non-sheet-passing regions causing potential damage
Solution Approach 1:
The shield is designed to be movable rather than fixed, allowing it to dynamically adjust its position between the heater and fixing belt. The shield moves to a first position when a sheet is present to allow heating, and to a second position when no sheet is present to block excessive heat, thus adapting the heating system's behavior to real-time conditions
Solution Approach 2:
The system incorporates a sheet detection mechanism that provides feedback about the presence or absence of a sheet. Based on this feedback, the control system adjusts the shield's position accordingly, creating a closed-loop control system that prevents excessive temperature rise while maintaining reliable fixing function
2Productivity
If the heater operates at high power to maintain temperature, then fixing speed is improved, but temperature control precision deteriorates due to excessive heat in non-sheet-passing regions
Solution Approach 1:
The shield dynamically adjusts its position based on sheet presence, allowing the heater to operate at high power when needed while preventing excessive heat accumulation. This dynamic adjustment maintains temperature control precision without sacrificing fixing speed
3Object-affected harmful factors
If the shield blocks more heat to prevent excessive temperature rise, then temperature control is improved, but the fixing belt temperature becomes insufficient for proper fixing
Solution Approach 1:
The shield's position is dynamically adjusted based on whether a sheet is present. When a sheet is present, the shield moves to allow maximum heat transmission to the fixing belt. When no sheet is present, the shield moves to block excessive heat. This dynamic positioning ensures adequate fixing belt temperature for proper fixing while preventing excessive temperature rise
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 excessive temperature rise in the fixing belt ends, ensuring stable operation and preventing fixing failures while maintaining productivity by dynamically adjusting the movable shield's position and temperature in response to varying print conditions.
Implementation Method 1
The heater heats the rotator
Implementation Method 2
The movable shield is disposed between the heater and the rotator to shield the rotator from radiant heat generated from the heater
Data Source
AI summary
An image forming apparatus includes an image forming section, a fixing device, and circuitry. The image forming section forms an image on a recording medium. The fixing device includes a rotator including a flexible endless belt, a pressure rotator pressed against the rotator to form a nip between the rotator and the pressure rotator, a heater heating the rotator, and a movable shield. The movable shield is disposed between the heater and the rotator to shield the rotator from radiant heat generated from the heater and is movable according to a size of the recording medium. The circuitry is configured to control the image forming section to form the image on the recording medium based on an image forming condition and change at least one of an operating temperature of the movable shield or a shielding amount of the movable shield based on the image forming condition.