Fixing Device Drive Shut-Off Mechanism for Jam Clearance
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Solution Overview
Problem
Conventional fixing devices face issues during jam clearance, where reverse rotation of the pressing roller can inadvertently engage the pendulum gear, leading to unnecessary operation of the pressing release drive, potentially causing damage due to retained pressure and vibration.
Innovation Solution
An image forming apparatus with a drive transmission mechanism using a gear with a one-way structure, incorporating a drive shut-off mechanism to prevent the pressing releasing mechanism from operating when the drive is received from the rotatable member, allowing normal and reverse rotations of the motor to switch between fixing drive and pressing release drive effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a pendulum gear or one-way clutch is used to switch drive paths in the fixing device, then the drive transmission can be switched between fixing drive and pressing release drive, but during jam clearance the pressing roller may rotate in reverse and inadvertently engage the pendulum gear, causing unnecessary operation of the pressing release drive
Solution Approach 1:
The patent introduces a drive shut-off mechanism as an intermediary component between the pressing roller and the pendulum gear. This mechanism includes a shut-off gear that can selectively engage or disengage from the pendulum gear, acting as a mediator to control whether reverse rotation of the pressing roller transmits to the pressing release drive. When the shut-off gear is disengaged, reverse rotation during jam clearance does not activate the pressing release drive, preventing erroneous operation.
Solution Approach 2:
The drive transmission path is segmented into controllable sections. The shut-off mechanism divides the continuous transmission path between the pressing roller and the pendulum gear into separate segments that can be independently controlled. By engaging or disengaging the shut-off gear, the system can isolate the pressing release drive from reverse rotation of the pressing roller, allowing selective transmission of drive forces in different operational modes.
2Adaptability or versatility
If the pressing release drive is engaged during jam clearance due to reverse rotation of the pressing roller, then the fixing portion is pressed, but this causes situations where several tens of N drawing force is needed to clear jammed paper or the jammed paper is broken
Solution Approach 1:
The drive shut-off mechanism serves as an intermediary that prevents the unintended transmission of reverse rotation to the pressing release drive during jam clearance. By disengaging the shut-off gear from the pendulum gear when reverse rotation is detected, the system isolates the pressing release drive, allowing the pressing roller to rotate freely in reverse without activating the pressing mechanism, thus enabling easy jam clearance without excessive drawing force requirements.
Solution Approach 2:
The shut-off mechanism is designed to preemptively prevent the harmful engagement of the pressing release drive during reverse rotation. By having the shut-off gear in a default disengaged state or capable of rapid disengagement upon detecting reverse rotation, the system applies preliminary anti-action to stop the erroneous pressing operation before it can occur, thereby preventing the need for high drawing force to clear jams.
3Reliability
If a large pressing release amount is set during jam clearance to prevent pressing roller rotation, then the pressing roller does not rotate, but the fixing device may be broken by vibration or impact when in a pressed state during transportation
Solution Approach 1:
The system dynamically adjusts the engagement state of the shut-off mechanism based on operational conditions. During normal operation, the shut-off gear is engaged to enable drive transmission. During jam clearance with reverse rotation, the shut-off gear disengages to allow free rotation. This dynamic adjustment allows the pressing release amount to be optimized for each condition: sufficient engagement during transport to prevent vibration damage, and sufficient release during jam clearance to allow free rotation without breaking paper.
Solution Approach 2:
The shut-off mechanism is positioned and configured to preliminarily prevent the transmission of reverse rotation to the pressing release drive before the harmful effect occurs. By having the shut-off gear ready to disengage upon detection of reverse rotation conditions, the system preliminarily protects against the scenario where excessive pressing force would be applied during jam clearance, thereby preventing paper breakage without requiring the pressing roller to remain in a pressed state during transportation.
Data Source
AI summary
A mechanism for shutting off drive so that drive of pressing release is not rotated even when a pressing roller is rotated as a driving source is provided, and a torque when drive of a shutting-off portion is connected is set at a torque value to which a one-way idling torque is added. Therefore, during jam clearance, connection of pressing release drive by pressing roller rotation can be carried out.