Heater Sensor Array for Uniform Temperature Control
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Solution Overview
Problem
Conventional image fixing apparatuses face challenges in accurately controlling the temperature of the heating roller, leading to temperature gaps that result in over-fixing, under-fixing, or shortened lifespan due to inaccurate temperature sensing from a single spot on the outer surface.
Innovation Solution
An image fixing apparatus with a sensor integrally formed with the heater to detect temperatures from multiple sensing positions, generating average temperature information and controlling the heater's on/off status to maintain a consistent temperature across the heating roller.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a temperature sensor is installed on the outer surface of the heating roller to detect temperature, then the temperature control system can be implemented, but the temperature detection accuracy deteriorates because the sensor cannot accurately reflect the actual heater temperature
Solution Approach 1:
The patent introduces a thermal conductor as an intermediary substance filling the cavity between the heater and the temperature sensor. This thermal conductor mediates the thermal interaction, allowing the sensor to accurately detect the heater temperature by conducting heat uniformly from the heater to the sensor, thereby resolving the measurement inaccuracy caused by the sensor's external placement
Solution Approach 2:
The temperature sensor is nested within the heating roller structure, specifically positioned in a cavity inside the roller. This nested configuration allows the sensor to be surrounded by the thermal conductor that is in contact with the heater, enabling accurate temperature detection while maintaining the sensor's protected position within the roller structure
2Device complexity
If the temperature sensor detects temperature from a single spot on the heating roller, then the sensor structure remains simple, but temperature distribution uniformity deteriorates due to temperature gaps between different regions of the roller
Solution Approach 1:
The patent applies local quality by positioning the temperature sensor specifically at the central region of the heating roller where temperature representation is most critical. The thermal conductor is distributed throughout the cavity to ensure uniform heat transmission from all regions of the heater to the sensor, creating localized optimal conditions for temperature measurement while maintaining overall system simplicity
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 ensures accurate temperature control, preventing overheating or underheating, thereby improving image fixation quality and extending the lifespan of the heater while maintaining a stable image fixing temperature.
Implementation Method 1
a heating roller 10, which houses a heater 11 therein
Implementation Method 2
A thermal sensor (such as a thermistor or thermostat) is generally used as the temperature sensor 30. The temperature sensor 30 detects the surface temperature of the heating roller 10
Implementation Method 3
an image fixing apparatus to fix an image onto a printing medium
Data Source
AI summary
An image fixing apparatus that senses temperature of a heater and controls the temperature accurately includes a pair of fixing rollers, a heater housed inside at least one of the pair of fixing rollers, and a sensor integrally formed with the heater to detect temperatures of the heater from a plurality of sensing positions. The sensor includes an array of sensing units connected in parallel to the plurality of sensing positions, and generates one sensing signal. An image forming apparatus includes the image forming apparatus. An image fixing temperature control method includes generating average temperature information of a heater; and controlling the driving of the heater based on the temperature information.