Fixing Belt Heating Control for Low-Temperature Startup Noise
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Solution Overview
Problem
Conventional image forming apparatuses do not adequately control the heater when starting the pressure roller in low-temperature environments, leading to irregular temperature distribution and belt deformation, which causes abnormal noise.
Innovation Solution
An image forming apparatus with a fixing device that includes a heating unit, a pressure roller, and temperature sensors, controlled by a controller to perform specific control operations to regulate motor speed and heater power based on ambient and heating unit temperatures, ensuring uniform temperature distribution and preventing belt deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the heater operates at high power when starting in low-temperature environment, then the heating efficiency is improved, but the belt temperature distribution becomes irregular causing belt deformation and abnormal noise
Solution Approach 1:
The control unit performs preliminary assessment of the ambient temperature before starting the heater. When low ambient temperature is detected, the control unit preemptively limits the heater's duty cycle to prevent irregular temperature distribution in the belt, thereby avoiding belt deformation and abnormal noise before they occur.
Solution Approach 2:
The control unit dynamically adjusts the heater's duty cycle based on real-time temperature conditions. In low-temperature environments, the duty cycle is restricted to a lower value to ensure uniform heating. As the temperature increases and conditions improve, the duty cycle can be increased to maintain efficient heating while preserving belt temperature uniformity.
2Productivity
If the motor rotates at high speed when starting in low-temperature environment, then the productivity is improved, but the motor becomes out of step due to grease solidification
Solution Approach 1:
The control unit performs preliminary assessment of the ambient temperature before starting the motor. When low ambient temperature is detected, the control unit preemptively limits the motor's rotational speed to prevent grease solidification and out-of-step conditions, thereby ensuring reliable motor operation before productivity requirements become critical.
Solution Approach 2:
The control unit dynamically adjusts the motor's rotational speed based on real-time temperature conditions. In low-temperature environments, the rotational speed is restricted to a lower value to prevent grease solidification issues. As the temperature increases and grease becomes more fluid, the rotational speed can be increased to maintain high productivity.
3Loss of time
If the heater operates at high power immediately after power on, then the heating speed is improved, but the belt deformation occurs due to irregular temperature distribution
Solution Approach 1:
The control unit performs preliminary assessment of the ambient temperature immediately after power on. When low ambient temperature is detected, the control unit preemptively limits the heater's duty cycle to prevent belt deformation, accepting a longer heating time in exchange for maintaining belt shape stability during the critical startup phase.
Solution Approach 2:
The control unit dynamically adjusts the heater's duty cycle based on real-time temperature conditions. In low-temperature environments, the duty cycle is restricted to a lower value to prevent belt deformation, even though this extends the heating time. As the temperature increases and the belt stabilizes, the duty cycle can be increased to reduce heating time.
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 effectively suppresses abnormal noise by maintaining uniform belt temperature and reducing motor speed in low-temperature conditions, thereby preventing belt deformation and enhancing noise suppression.
Implementation Method 1
The heating unit includes a heater. The controller is configured to perform a heating process to raise a temperature of the heating unit to a target temperature
Data Source
AI summary
An image forming apparatus includes a fixing device, a motor, and a controller. The fixing device includes a heating unit and a first temperature sensor. The controller is configured to perform driving the fixing device. The driving includes a heating process. The controller is further configured to perform, during the heating process: a first control operation in which the controller rotates the motor at a first rotational speed and adjusts a duty cycle of electric power suppled to a heater of the heating unit to a higher value as a deviation between a target temperature and a temperature detected by the first temperature sensor becomes greater; and a second control operation in which the controller rotates the motor at a second rotational speed lower than the first rotational speed and restricts the duty cycle within a range lower than or equal to a restricted value.