Drive Transmission Mechanism for Fixing Device Roller Separation
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Solution Overview
Problem
Existing fixing devices in image forming apparatuses require large and expensive motors to achieve the necessary drive torque for separating the pressure roller from the fixing roller, leading to increased size and cost of the device and apparatus.
Innovation Solution
A fixing device incorporating a planetary gear device and a worm gear to transmit the driving force from a compact and less expensive drive motor, providing a high reduction ratio to overcome the load torque and enable efficient separation of the pressure roller from the fixing roller.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a motor with large drive torque is used to separate the pressure roller from the fixing roller, then the separation function is reliable, but the size and cost of the fixing device increase
Solution Approach 1:
A cam mechanism is introduced as an intermediary between the motor and the pressure roller. The cam converts rotational motion into linear motion, providing mechanical advantage to separate the pressure roller from the fixing roller without requiring the motor to directly generate the full separation force. This mediator allows a smaller motor to achieve the necessary separation effect.
Solution Approach 2:
The system transitions from a static pressure application mode to a dynamic separation mode. During normal operation, the pressure roller maintains contact with the fixing roller under spring bias. When separation is needed, the cam dynamically moves to push the pressure roller away, creating a temporary dynamic state that overcomes the spring force without requiring continuous high motor torque.
2Reliability
If a motor with large drive torque is used to separate the pressure roller from the fixing roller, then the separation function is reliable, but the cost of the fixing device increases
Solution Approach 1:
The cam mechanism serves as a cost-effective intermediary that provides mechanical advantage. Instead of using an expensive high-torque motor, the system employs a simple cam profile that leverages the motor's rotational motion to generate the necessary separation force, significantly reducing component costs while maintaining separation reliability.
Solution Approach 2:
By utilizing dynamic motion through the cam mechanism, the system achieves separation with a smaller, less expensive motor. The dynamic action of the cam pushing the pressure roller during specific phases of rotation allows the use of a lower-cost motor that doesn't need to continuously overcome the full spring bias force.
3Ease of operation
If the pressure roller is moved away from the fixing roller against the biasing force, then the separation function is achieved, but a large load torque is applied to the cam
Solution Approach 1:
The cam mechanism utilizes dynamic motion to overcome the large load torque. By applying the separating force during a specific dynamic phase of the cam rotation rather than statically, the system leverages the momentum and mechanical advantage of the cam profile to reduce the peak torque requirements on the cam and motor assembly.
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 configuration allows for the use of a smaller, more affordable motor while maintaining the necessary output torque, reducing the size and cost of the fixing device and image forming apparatus, and enhancing startup time by enabling simultaneous adjustment of the pressing force and temperature increase.
Implementation Method 1
The drive transmitter is configured to transmit the driving force of the drive source to the moving body and includes a planetary gear device and a worm gear
Implementation Method 2
The drive transmitter is configured to transmit the driving force of the drive source to the moving body and includes a planetary gear device and a worm gear
Implementation Method 3
The fixing roller is configured to be heated by the heater
Implementation Method 4
The fixing roller is configured to be heated by the heater
Implementation Method 5
The pressure roller functions as a pressing member to be pressed to the fixing roller by a biasing member such as a pressure spring
Data Source
AI summary
A fixing device, which is included in an image forming apparatus, includes a heater, a heating target body, a biasing body, a pressure body, a moving body, a drive source, and a drive transmitter. The heating target body is configured to be heated by the heater. The biasing body is configured to apply a biasing force. The pressure body is configured to be pressed by the biasing body toward the heating target body. The moving body is configured to move the pressure body away from the heating target body against the biasing force applied by the biasing body. The drive source is configured to apply a driving force. The drive transmitter is configured to transmit the driving force of the drive source to the moving body and includes a planetary gear device and a worm gear.