Fixing Roller Temperature Control via Noncontact Infrared Detection
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Solution Overview
Problem
Conventional noncontact-type temperature detecting methods for fixing rollers in image forming apparatuses face challenges such as scratches, heat resistance issues, and inaccurate temperature control due to noise in output signals, especially with increasing rotation speeds and environmental disturbances.
Innovation Solution
A temperature control device that uses a main thermistor to detect infrared radiation from the fixing roller, a compensation thermistor to account for ambient temperature, and a temperature correspondence table to accurately calculate and control the heating power, ensuring precise temperature detection and control without contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a temperature detecting element contacts the fixing roller to detect temperature, then the temperature detection accuracy is improved, but the fixing roller surface suffers scratches or damages
Solution Approach 1:
The patent introduces a temperature detecting element that detects temperature non-contactly through the fixing roller surface, using the surface as an intermediary medium. The element measures temperature via thermal radiation or conduction through the surface without physical contact, thus avoiding scratches while maintaining detection accuracy
Solution Approach 2:
The patent replaces the mechanical contact-based temperature detection method with a non-contact method such as infrared detection or optical measurement. This substitution eliminates mechanical wear and surface damage while preserving the ability to accurately measure the fixing roller temperature
2Object-affected harmful factors
If a noncontact-type temperature detecting element is placed near the fixing roller, then scratches and damages are prevented, but the heat resistance of the detecting element becomes a problem
Solution Approach 1:
The patent positions the temperature detecting element at a distance from the fixing roller, using the space between them as an intermediary. This allows non-contact temperature measurement through thermal radiation without exposing the detecting element directly to the high-temperature surface, reducing heat resistance requirements
Solution Approach 2:
The patent uses the fixing roller surface itself as a mediator for temperature detection. The surface transmits thermal information to the detecting element without the element needing to withstand direct contact temperatures, effectively copying the temperature data through the surface medium
3Productivity
If the rotation speed of the fixing roller is increased to achieve high-speed operation, then productivity is improved, but the conventional contacting temperature detection method causes more frequent scratches and damages
Solution Approach 1:
The patent replaces mechanical contact-based temperature detection with non-contact detection methods such as infrared sensing or optical measurement. This allows the fixing roller to rotate at high speeds without the detecting element causing scratches or damages, enabling high-speed operation while maintaining temperature monitoring capability
Solution Approach 2:
The patent introduces a non-contact temperature detection system that measures temperature through thermal radiation or field interaction rather than mechanical contact. This intermediary measurement method allows the fixing roller to operate at high rotation speeds without the detecting element interfering with or damaging the surface
4Object-affected harmful factors
If a thermopile element is used for noncontact temperature detection, then scratches are prevented, but the output signal contains large noise and accurate detection becomes impossible
Solution Approach 1:
The patent uses the fixing roller surface as an intermediary medium between the thermal source and the temperature detecting element. This surface-mediated detection approach filters out some environmental noise while maintaining accurate temperature measurement capability
Solution Approach 2:
The patent employs a temperature detecting element that accurately copies or replicates the true temperature of the fixing roller surface. By using a well-calibrated detecting element with appropriate signal processing, the system produces a clean output signal that accurately represents the actual temperature without excessive noise
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
The solution enables accurate and stable temperature control of the fixing roller, improving image quality by maintaining precise temperature settings even under varying environmental conditions and high-speed operations.
Implementation Method 1
a main temperature detecting section which detects heat generated by infrared radiation from the heated object
Implementation Method 2
The heater for heating the fixing roller is usually a heater which converts electric energy to heat energy
Data Source
AI summary
The present invention carries out temperature detection and temperature control accurately in a temperature control device using a noncontact-type temperature detecting section. The temperature control device obtains the surface temperature of a fixing roller by using a temperature correspondence table in which correspondences between output voltage values of a main NTC thermistor which detects heat generated by infrared radiation from the fixing roller and the surface temperatures of the fixing roller are shown for respective output voltage values of a compensation NTC thermistor. Here, the output voltage values of the main NTC thermistor and the output voltage values of the compensation NTC thermistor are set in the temperature correspondence table so that an interval between adjacent values of the compensation temperatures corresponding to the output voltage values of the compensation NTC thermistor is smaller than an interval between adjacent values of the surface temperatures of the fixing roller which temperatures correspond to the output values of the main NTC thermistor.