Dual-Sensor Heat Receiving Member Temperature Control
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Solution Overview
Problem
Existing image forming apparatuses face issues with temperature rise at the end portion of the heat receiving member, leading to poor fixing and potential damage, especially when using nonstandard-size sheets or varying heater capabilities due to manufacturing variability and power supply fluctuations.
Innovation Solution
The apparatus employs a dual-temperature sensing system with a first temperature sensor at the center and a second sensor away from the center, allowing the controller to determine a temperature difference and perform temperature reduction control by adjusting the number of sheets printed per unit time and increasing the threshold value with time elapsed, thereby reducing unnecessary control modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the apparatus controls temperature rise at the end portion by increasing sheet supply interval when temperature exceeds threshold, then temperature rise is prevented, but productivity decreases due to unnecessary control mode entry
Solution Approach 1:
The system performs preliminary heating before actual printing to establish a baseline temperature relationship between the center and end portions of the heat receiving member. This preliminary action allows the system to predict when temperature rise at the end portion will become problematic, enabling control decisions to be made based on predicted rather than reactive temperature measurements, thus avoiding unnecessary productivity reductions
Solution Approach 2:
The system continuously monitors the temperature difference between the center and end portions of the heat receiving member and adjusts the sheet supply interval dynamically. The feedback mechanism compares the actual temperature difference with a threshold value, and only triggers productivity-reducing control measures when the threshold is exceeded, thereby optimizing the balance between temperature control and printing efficiency
2Device complexity
If the apparatus uses a single temperature sensor at the center to control temperature, then device complexity is reduced, but measurement precision is insufficient to detect temperature rise at the end portion
Solution Approach 1:
The temperature monitoring function is segmented into two separate measurement points: a first temperature sensor at the center portion and a second temperature sensor at the end portion of the heat receiving member. This segmentation allows independent measurement of temperatures at different locations, enabling accurate detection of temperature differences and gradients that would be impossible with a single sensor, thereby improving measurement precision without excessive complexity
Solution Approach 2:
The controller acts as an intermediary that processes temperature data from both sensors, calculates the temperature difference, and determines when control action is needed. This intermediary processing layer enables the system to derive meaningful information (temperature difference trend) from multiple sensor inputs, achieving high measurement precision while keeping the overall device complexity manageable through intelligent data processing
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 effectively mitigates temperature rise at the end portion of the heat receiving member, preventing damage and ensuring proper fixing, especially for nonstandard-size sheets, while minimizing the impact of varying heater capabilities and power supply conditions.
Implementation Method 1
a heater configured to generate heat
Implementation Method 2
a heat receiving member for receiving heat from the heater
Implementation Method 3
a heat receiving member for receiving heat from the heater and configured to fix the toner image on the sheet
Implementation Method 4
a first temperature sensor configured to sense a first temperature at a center portion of the heat receiving member in the width direction
Implementation Method 5
a second temperature sensor disposed away from a center of the heat receiving member in a width direction further than the first temperature sensor, the width direction being orthogonal to a sheet conveying direction, the second temperature sensor being configured to sense a second temperature of the heat receiving member
Data Source
AI summary
An image forming apparatus includes an image forming unit, a heater, a heat receiving member configured to fix a toner image on a sheet, a first temperature sensor configured to sense a first temperature of the heat receiving member, a second temperature sensor configured to sense a second temperature of the heat receiving member, and a controller. The controller is configured to, after the image forming unit starts image formation: when a difference between the first temperature and the second temperature exceeds a threshold value a first number of times, perform a temperature reduction control in which the controller reduces a number of sheets to be printed per unit time and the image forming unit performs image formation for the reduced number of sheets to be printed per unit time; and increase the threshold value in accordance with a time elapsed.