Dual Sensor Temperature Control for Fusing Unit Condensation
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Solution Overview
Problem
Conventional image forming devices face issues with temperature detection accuracy due to condensation and contamination affecting infrared temperature sensors, leading to erroneous temperature control and increased maintenance costs.
Innovation Solution
An image forming device with a dual temperature detection system using a non-contact infrared temperature sensor and a thermistor, where the temperature controller selectively switches between two control modes based on detected temperature differences and elapsed time to distinguish between condensation and contamination, activating a warning device when necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a contact type temperature detector (thermistor) is used to detect the surface temperature of the heating roller, then the temperature detection is direct and reliable, but the thermistor is susceptible to abnormalities such as disconnection, short circuit, and damage to the heating roller surface, requiring frequent replacement and increasing maintenance costs
Solution Approach 1:
The patent introduces an intermediary substance (transparent adhesive layer) between the thermistor and the heating roller surface. This adhesive layer acts as a protective mediator that transmits temperature while preventing direct contact between the thermistor and the heating roller, thereby reducing damage to both components and lowering maintenance costs while maintaining reliable temperature detection
2Ease of repair
If a non-contact infrared temperature sensor is used to detect the surface temperature of the heating roller, then the sensor is protected from damage and replacement cost is reduced, but condensation and contamination on the sensor surface cause erroneous temperature detection
Solution Approach 1:
The patent uses a transparent adhesive layer as an intermediary between the infrared sensor and the heating roller. This adhesive layer transmits infrared radiation while protecting the sensor from condensation and contamination, thereby maintaining both the protective advantage and the measurement accuracy
Solution Approach 2:
The patent replaces the mechanical contact-based temperature detection (thermistor directly touching the roller) with a non-contact infrared detection system, eliminating mechanical wear and damage while maintaining accurate temperature measurement through optical means
3Device complexity
If the thermistor is attached to the fusing unit, then the temperature detection is integrated with the fusing mechanism, but the thermistor must be replaced along with the entire fusing unit when damaged, increasing replacement cost and resource waste
Solution Approach 1:
The patent segments the temperature detection component (thermistor) from the fusing unit by using a removable adhesive layer. This allows the thermistor to be independently replaced without replacing the entire fusing unit, reducing replacement costs and resource waste while maintaining integrated functionality during operation
4Device complexity
If conventional temperature detection methods are used, then the system structure is simple, but temperature control abnormalities occur due to condensation and contamination on the detection sensor
Solution Approach 1:
The transparent adhesive layer serves as a protective intermediary that prevents condensation and contamination from reaching the temperature sensor surface, thereby maintaining reliable temperature control without significantly complicating the system structure
Solution Approach 2:
The patent transitions from contact-based temperature detection to non-contact infrared detection, eliminating the problem of condensation and contamination on the sensor surface while maintaining a relatively simple system structure through the use of transparent protective layers
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
Accurately differentiates between temporary and permanent erroneous detections, preventing temperature control abnormalities and reducing maintenance costs by distinguishing between condensation and contamination, ensuring reliable print quality and efficiency.
Implementation Method 1
a first temperature detector for detecting, based on an amount of infrared rays incident upon the light receiving body from the heated body, a first temperature equivalent to a surface temperature of the heated body
Implementation Method 2
a second temperature detector for detecting, based on a temperature of the heat receiving body heated by the heated body, a second temperature equivalent to the surface temperature of the heated body
Implementation Method 3
a heater for heating the heated body
Data Source
Figure 1
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Figure 3
AI summary
A first temperature (T1) is obtained based on an amount of infrared rays incident upon a lens (38) of an infrared temperature sensor (30), and a second temperature (T2) is obtained based on a temperature of a thermistor (40). A system controller (90) performs first temperature control (S10 to S12) when a detected temperature difference (ΔT) between the first temperature (T1) and the second temperature (T2) is less than a predetermined temperature difference (PT) (Y in S12), performs second temperature control (S22 to S25, and S42 to S45) when the detected temperature difference (ΔT) is equal to or greater than the predetermined temperature difference (PT) (N in S12), and activates an alarm (29) (S60) when an elapsed time (C2) during which the second temperature control is continuously executed has become equal to or greater than a time that is the sum of a first predetermined time (P1) and a second predetermined time (P2) (S24 & S44).