Fixing Roller Temperature Control for Power Saving
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Solution Overview
Problem
The existing image forming apparatuses consume high power due to inefficient temperature control in fixing devices, as the heat conductor and pressure roller have different heat capacities, leading to wasteful heating when transitioning between image forming and power saving modes.
Innovation Solution
The implementation of a temperature control method that includes a heat conductor, a pressure roller with higher heat capacity, and a control system that rotates the heat conductor when its temperature falls below a specific threshold, utilizing heat from the pressure roller to maintain the heat conductor at a lower wait temperature, thereby reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the heat source is operated to maintain the fixing roller at the fixing temperature during image non-forming period, then the toner image can be quickly fixed during image formation, but the power consumption increases significantly
Solution Approach 1:
The patent changes the temperature parameter of the fixing roller from fixing temperature (e.g., 200°C) to wait temperature (e.g., 50-150°C) during image non-forming periods. This parameter change allows significant power reduction while maintaining the ability to quickly reach fixing temperature when needed, resolving the contradiction between productivity and energy consumption.
Solution Approach 2:
The patent performs preliminary heating to wait temperature during non-forming periods instead of maintaining fixing temperature. This preliminary action prepares the fixing roller for quick operation when image formation is needed, reducing the heating time and energy consumption during mode transitions.
2Use of energy by moving object
If the heat source is stopped to reduce power consumption during image non-forming period, then the power consumption decreases, but the fixing roller temperature drops below the wait temperature requiring additional heating
Solution Approach 1:
The patent implements feedback control by continuously monitoring the fixing roller temperature and comparing it with the wait temperature. When the temperature drops below the wait temperature threshold, the heat source is automatically restarted. This feedback mechanism ensures reliable temperature maintenance while minimizing power consumption during non-forming periods.
3Loss of time
If the fixing roller temperature is quickly raised to fixing temperature upon receiving image forming instruction, then the image formation can start immediately, but the heating time and energy consumption increase
Solution Approach 1:
The patent performs preliminary heating action during non-forming periods to raise the fixing roller to wait temperature. This preliminary action reduces the heating time and energy consumption when the fixing roller needs to be quickly brought to fixing temperature upon receiving image formation instructions, as it only needs to heat from wait temperature rather than from room temperature.
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 reduces power consumption by minimizing unnecessary heating, allowing for quicker transitions between modes and maintaining the heat conductor at optimal temperatures for efficient image forming.
Implementation Method 1
The heating portion is configured to heat the heat conductor
Implementation Method 2
A heat source, such as a heater, is embedded in the fixing roller
Implementation Method 3
The heat conductor is rotatably supported and configured to conduct heat to a sheet to which a toner image has been transferred
Implementation Method 4
The temperature detecting portion is configured to detect a surface temperature of the heat conductor
Implementation Method 5
The pressure roller is configured to form a pressure contact portion by pressing and contacting the heat conductor and apply a pressure onto a sheet that passes through the pressure contact portion
Data Source
AI summary
An image forming apparatus includes a fixing device. The fixing device includes a fixing roller and a pressure roller. The fixing roller applies heat of a predetermined fixing temperature T1 to a print sheet S to which a toner image has been transferred. The pressure roller has a larger heat capacity than the fixing roller. A control portion of the image forming apparatus determines, in a power saving mode, whether or not a detection result of a temperature sensor is equal to or lower than a motor rotation start temperature T3 which is lower than the fixing temperature T1 (first step). Upon determining that the detection result is equal to or lower than the motor rotation start temperature T3, the control portion controls a driving motor to rotate the fixing roller at least once in the state where a halogen lamp has been lighted off (second step).