Fixing Roller Temperature Control via Torque Detection
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Solution Overview
Problem
In image forming apparatuses, dew condensation on the pressing roller leads to a slip phenomenon, causing image defects and jams, especially when the surface temperature of the pressing roller is low, and existing solutions require unnecessary stand-by time to prevent this issue.
Innovation Solution
An image forming apparatus with torque detecting means to control the temperature rise of the rotatable members before the recording material enters the nip, using the detected driving torque to prevent dew condensation slip by extending the pre-rotation time or sheet interval time, thereby minimizing user wait time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the surface temperature of the pressing roller is increased to prevent dew condensation slip, then the reliability of the fixing device is improved, but the productivity decreases due to extended warm-up time
Solution Approach 1:
The system performs preliminary warming of the pressing roller surface by extending the rotation time before the recording material enters the nip. This preliminary action ensures the surface temperature is sufficiently high to prevent dew condensation slip, while minimizing the warm-up time required by using the extension of pre-rotation time rather than prolonged heating.
Solution Approach 2:
The system dynamically adjusts the pre-rotation time based on detected torque values. When the torque indicates insufficient surface temperature, the pre-rotation time is extended; when the torque indicates adequate temperature, the pre-rotation time is reduced. This dynamic adjustment optimizes the balance between preventing dew condensation slip and maintaining high printing speed.
2Reliability
If the pre-rotation time is extended to warm the pressing roller surface, then the reliability is improved, but the loss of time increases due to stand-by time
Solution Approach 1:
The system uses torque detecting means to monitor the driving torque of the motor during pre-rotation. Based on the detected torque values, the control means determines whether the pressing roller surface has reached sufficient temperature. This feedback mechanism eliminates unnecessary stand-by time by extending pre-rotation only until the surface temperature is adequate, rather than using fixed extended warm-up periods.
3Productivity
If the image forming speed is increased to improve productivity, then the printing speed is improved, but the reliability deteriorates due to insufficient warming of the pressing roller
Solution Approach 1:
The system performs preliminary warming of the pressing roller surface by extending the rotation time before the recording material enters the nip. This preliminary action ensures the surface temperature is sufficiently high to prevent dew condensation slip, while minimizing the warm-up time required by using the extension of pre-rotation time rather than prolonged heating.
Solution Approach 2:
The system dynamically adjusts the pre-rotation time based on detected torque values. When the torque indicates insufficient surface temperature, the pre-rotation time is extended; when the torque indicates adequate temperature, the pre-rotation time is reduced. This dynamic adjustment optimizes the balance between preventing dew condensation slip and maintaining high printing speed.
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
Effectively reduces the occurrence of dew condensation slip without adding unnecessary stand-by time, ensuring continuous printing with reduced image defects and jams.
Implementation Method 1
torque detecting means for detecting a driving torque of the motor
Implementation Method 2
a heater, a cylindrical film rotatable while contacting the heater at an inner peripheral surface
Implementation Method 3
a phenomenon occurs in which water vapor, which generates from the recording material in a process in which the recording material is heated while being nipped and fed through the nip, condenses (forms dew) on an outer peripheral surface of the pressing roller
Data Source
AI summary
An image forming apparatus includes an image forming portion configured to form an image on a recording material, and a fixing portion including a first rotatable member and a second rotatable member, rotatable by rotation of the first rotatable member, and in contact with the first rotatable member. The fixing portion fixes the image on the recording material by heating the image while nipping and feeding the recording material, on which the image is formed, at a nip formed between the first rotatable member and the second rotatable member. A motor drives the first rotatable member, and torque detecting means detects a driving torque of the motor. On the basis of the driving torque detected by the torque detecting means, a controller controls a degree of temperature rise of the first rotatable member immediately before the recording material enters the nip.