Fixing Belt Temperature Control via Segmented Cooling and Heating
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Solution Overview
Problem
Existing image forming apparatuses face productivity issues when handling mixed recording media due to temperature fluctuations in the fixing nip, particularly when switching from thick to thin paper, leading to inefficiencies in heat supply and fixing failure.
Innovation Solution
A fixing apparatus with a rotatable fixing belt, pressing roller, heating roller, cooling fan, temperature detecting member, and controller is used to dynamically adjust heat supply and cooling based on detected temperatures, ensuring optimal temperature levels for different paper types by controlling the heater and cooling fan operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a heater is disposed within a hollow of the fixing roller to make the fixing roller store heat, then the fixing roller can supply sufficient heat for thick paper, but the temperature adjustment time becomes excessively long when switching between different paper types
Solution Approach 1:
The invention divides the thermal management system into two independent parts: a heater disposed within the hollow of the fixing roller for heating, and a cooling fan disposed in the downstream area to provide active cooling. This segmentation allows the heating and cooling functions to operate independently and simultaneously, enabling rapid temperature adjustment when switching between different paper types without requiring the entire fixing roller to heat up or cool down uniformly.
Solution Approach 2:
The cooling fan acts as an intermediary cooling device that actively removes excess heat from the fixing roller surface. By introducing this intermediary cooling mechanism, the system can rapidly reduce the fixing roller temperature when switching from thick to thin paper without waiting for passive cooling, thereby significantly reducing the temperature adjustment time while maintaining the heat storage capability of the fixing roller.
2Productivity
If the fixing roller is made large in thermal capacity to maintain temperature for thick paper, then sufficient heat is supplied for high basis weight recording medium, but the temperature cannot be quickly reduced when switching to thin paper
Solution Approach 1:
The invention implements dynamic thermal control by combining a heater for heating with a cooling fan for active cooling. This dynamic system can rapidly adjust the fixing roller temperature according to the requirements of different paper types, enabling the fixing apparatus to adapt quickly between thick and thin paper without significant downtime, thereby maintaining high productivity while improving adaptability to various recording medium types.
Solution Approach 2:
The system changes the thermal parameters of the fixing roller dynamically by using the heater to increase temperature when thick paper is detected and using the cooling fan to decrease temperature when thin paper is detected. This parameter change approach allows the fixing roller to maintain optimal temperature for different paper types, improving both productivity and adaptability.
3Temperature
If cooling is provided in the upstream area before the nip, then the fixing belt temperature can be reduced, but the heating efficiency in the nip area is compromised
Solution Approach 1:
The invention applies local quality by positioning the cooling fan in the downstream area of the fixing belt, specifically in the area downstream of the nip. This localized cooling approach ensures that the heating efficiency in the nip area is maintained while providing temperature reduction in the downstream area where cooling is most needed, avoiding the energy waste that would result from cooling the entire fixing belt including the heating zone.
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 maintains high productivity by quickly adjusting to changing paper types, reducing downtime and ensuring effective toner fixation across various media, thereby enhancing the overall efficiency of the image forming process.
Implementation Method 1
a cooling fan, which cools the fixing belt and is disposed opposite to a surface of the belt at a position downstream of the heating roller and upstream of the nip forming member
Implementation Method 2
a heating roller, which includes a heater therein and stretches the fixing belt
Data Source
AI summary
An image fixing device includes a rotatable fixing belt, a pressing roller, a nip forming member, a heating roller, a cooling fan, a temperature sensor, and a controller. The nip forming member contacts an inner surface of the fixing belt to sandwich the fixing belt between the pressing roller to form a nip. The heating roller stretches the fixing belt. The cooling fan cools the fixing belt and is opposite to the belt at a position downstream of the heating roller and upstream of the nip forming member in the rotational movement direction of the fixing belt. The temperature sensor detects a temperature of the fixing belt and is provided at a position downstream of the cooling fan and upstream of the nip. The controller controls the power supplied to the heater on the basis of an output of the temperature sensor.