WAE Control for Image Forming Apparatus Temperature
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Image forming apparatuses face challenges in accurately controlling the surface temperature of fixing units due to temperature sensor responsiveness issues, leading to overshoot and temperature ripples, and high costs associated with responsive temperature sensors, especially in environments without power supply voltage detection.
Innovation Solution
Implementing a Weighted Average Estimation (WAE) control function that simulates a thermal CR circuit to estimate the surface temperature of the fixing unit, using the CR time constant to adjust energization based on input voltage and heat capacity, and communicating with other apparatuses for accurate power supply voltage detection to refine temperature control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a temperature sensor with good responsiveness (e.g., thermopile) is used to detect the surface temperature of the fixing rotating body, then temperature control precision is improved, but device cost increases
Solution Approach 1:
The patent introduces a thermal model (CR circuit model) as an intermediary to estimate the surface temperature of the fixing rotating body. Instead of directly measuring the difficult-to-access surface temperature with expensive sensors, the system uses a thermal model that calculates surface temperature based on heating element temperature and heat transfer characteristics, thereby achieving accurate temperature control without costly sensors
Solution Approach 2:
The patent creates a thermal model (electrical CR circuit model) that copies the thermal behavior of the fixing unit. By measuring the temperature of the heating element (which is easier to measure) and using the thermal model to calculate the surface temperature, the system obtains accurate surface temperature information without placing a sensor directly on the rotating body surface
2Device complexity
If conventional temperature sensors are used to detect the surface temperature of the fixing rotating body, then device cost is reduced, but temperature control precision deteriorates due to overshoot and temperature ripple
Solution Approach 1:
The thermal model acts as an intermediary that processes the heating element temperature measurement and predicts the surface temperature. This model-based approach compensates for the limitations of conventional sensors by calculating the actual surface temperature based on heat transfer physics, thereby maintaining temperature control precision while using lower-cost sensors
Solution Approach 2:
The system performs preliminary temperature estimation using the thermal model before actual surface temperature measurement is needed for control decisions. By continuously calculating the expected surface temperature based on heating power and thermal characteristics, the system proactively compensates for temperature changes before they cause overshoot or ripple
3Measurement precision
If WAE control function is implemented to estimate surface temperature based on CR circuit model, then temperature control precision is improved, but device complexity increases
Solution Approach 1:
The patent replaces the physical temperature sensor measurement system with a computational thermal model. Instead of using complex hardware to directly measure surface temperature, the system uses mathematical calculations based on the CR circuit model, substituting mechanical/physical measurement with computational estimation
Solution Approach 2:
The system changes the measurement parameter from direct surface temperature measurement to heating element temperature measurement combined with thermal model calculation. By measuring a different parameter (heating element temperature) and using the thermal model to derive surface temperature, the system achieves the same control objective with simpler hardware
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 approach allows for precise temperature control, reducing overshoot and temperature ripples while maintaining cost-effectiveness by leveraging existing power supply voltage detection networks, even in environments without dedicated power supply voltage detection devices.
Implementation Method 1
a heating member (lamp, IH heater, or the like)... by increasing or decreasing the energization amount to the heating member
Implementation Method 2
a temperature sensor with good responsiveness (for example, thermopile or the like)
Implementation Method 3
the heat capacity of the fixing unit is replaced by the capacitance C, and the heat transfer resistance is replaced by the resistance R
Data Source
AI summary
An image forming apparatus includes a heating member energization control circuit that estimates a temperature of a fixing rotating body, based on a temperature detection result of the fixing rotating body, which is heated by a heating member and heats a toner image formed on a medium to fix the toner image on the medium, by a temperature sensor, a power supply voltage of a power supply source, and an energization pulse for controlling energization to the heating member, and outputs an energization pulse for controlling power to be supplied to the heating member, based on the estimated temperature and the temperature detection result. The apparatus further includes a controller that acquires a power supply voltage detection result by a communication interface via a network, from another apparatus which holds a power supply voltage detection result by an image forming apparatus with a power supply voltage detection function, provided with a power supply voltage detection circuit that detects a power supply voltage value of a same power supply source as the power supply source, and inputs the acquired power supply voltage detection result to the heating member energization control circuit, as a power supply voltage value of the power supply source.