External Heating Belt Fixing Apparatus Rotation Control
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Solution Overview
Problem
Conventional roller pair type fixing apparatuses face issues with maintaining constant surface temperature of the fixing roller, especially when multiple sheets pass through at high speeds, and external heating type fixing apparatuses suffer from rotation troubles due to deformed endless belts, leading to slip and scratching problems.
Innovation Solution
A fixing apparatus with an external heating device where a belt is heated by a first heating section and rotated when it reaches a target temperature, preventing deformed shape-related rotation troubles by ensuring the belt is softened and rotated in sync with the fixing member.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a roller pair type fixing apparatus with internal heating is used, then the fixing roller can be heated from inside, but the temperature of the surface of the fixing roller is extremely decreased when multiple sheets pass through at high speed, making it difficult to maintain constant temperature
Solution Approach 1:
The patent introduces an external heating belt as an intermediary heating element that directly contacts the fixing roller surface. The belt is heated separately and then wrapped around the fixing roller to transfer heat directly to the surface, bypassing the poor thermal conductivity issue of the elastic layer in internal heating systems. This mediator enables rapid surface heating even at high sheet passing speeds.
Solution Approach 2:
The patent replaces the thermal conduction mechanism (internal heating through elastic layer) with a direct thermal contact mechanism (external heating belt wrapping). Instead of relying on heat conduction through materials, the system uses direct thermal contact between the heated belt and fixing roller surface, significantly improving heat transfer efficiency and response speed.
2Temperature
If an endless belt is left for a long time with no rotation at high temperature, then the belt remains in a deformed shape, causing rotation troubles such as slip when the fixing roller is started to rotate
Solution Approach 1:
The patent applies preliminary cooling action by providing a cooling section that cools the endless belt after it has been heated. This preliminary cooling prevents the belt from remaining in a deformed high-temperature state, thereby preventing rotation troubles such as slip when the fixing roller is started to rotate. The cooling section ensures the belt returns to its proper shape and temperature before rotation begins.
3Temperature
If the external heating belt is pressed against the fixing roller during warm-up or standby mode, then the fixing roller can be heated, but the fixing roller may leave a trace on the belt or scratch the belt surface due to toner accumulation
Solution Approach 1:
The patent implements periodic action by controlling the pressing and releasing of the external heating belt against the fixing roller. During warm-up or standby mode, the belt is pressed to provide heating. Before the fixing roller rotates, the belt is released to prevent trace or scratch formation. This periodic pressing and releasing ensures both effective heating and prevention of harmful effects.
4Use of energy by stationary object
If the endless belt is set around two belt supporting rollers with small diameter to minimize heat capacity, then the belt can be heated quickly, but the belt will remain in an elliptic deformed shape when left for a long time, causing rotation trouble
Solution Approach 1:
The patent applies parameter changes by cooling the endless belt after heating to change its physical state from a high-temperature deformed state to a low-temperature stable state. This parameter change (temperature reduction) prevents the belt from maintaining its elliptic deformed shape, thereby preventing rotation troubles such as slip when the fixing roller is started to rotate.
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
Prevents rotation troubles such as slip and ensures proper heating and fixing of images by maintaining the belt's flexibility and preventing deformed shape issues, thus ensuring efficient and consistent operation.
Implementation Method 1
a first heating section for heating the belt
Implementation Method 2
the belt is heated and is brought into contact with a fixing roller, thereby heating a surface of the fixing roller
Data Source
AI summary
For start of rotation of a fixing roller that is not currently being rotated, a control device causes a halogen lamp to heat an endless belt until a thermistor detects that a surface temperature of the endless belt has reached a first target temperature set at a temperature at which the endless belt is softened and is restored to its normal shape, from a deformed shape that the endless belt had while it was not rotated, to such an extent that the endless belt will never cause any rotation trouble during the rotation. This prevents the rotation trouble of the belt in a fixing apparatus in which a fixing member is heated by bringing the thus heated belt into contact with the fixing member.