Auxiliary Pressing Member for Hook Engagement in Image Formers
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In image forming apparatuses, the large reaction force required to engage the hook with the boss affects the nip pressure between rollers, leading to sheet conveying failures and reduced workability due to the need for high spring force and potential misalignment of the outer cover's pushing direction with the conveying unit's turning direction.
Innovation Solution
An auxiliary pressing member is introduced to press the hook member in a direction different from the conveying unit's turning direction, ensuring firm engagement with the boss without affecting the nip pressures, and allowing for smoother operation by reducing the required spring force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the spring force is increased to engage the hook with the boss, then the engagement force is improved, but the disengagement workability deteriorates
Solution Approach 1:
The engagement mechanism is divided into two independent functional parts: a spring mechanism for initial engagement and an auxiliary pressing member for reinforcement. This segmentation allows each component to perform its specific function without interfering with the other, enabling the spring to provide engagement force while the auxiliary member ensures firm engagement without requiring excessive spring force that would hinder disengagement.
Solution Approach 2:
The auxiliary pressing member acts as an intermediary that applies additional pressing force to the hook after the spring has engaged it with the boss. This intermediary component bridges the gap between the spring's engagement force and the required firm engagement, allowing the spring to maintain moderate force levels while the auxiliary member provides the additional pressing force needed for reliable engagement.
2Force
If the outer cover pushes the hook to engage with the boss, then the engagement is achieved, but the nip pressure between rollers is affected causing sheet conveying failure
Solution Approach 1:
The pressing function is segmented into two stages: initial engagement by the spring and reinforcement pressing by the auxiliary pressing member. This segmentation allows the pressing force to be applied in a controlled manner that does not transmit excessive force to the rollers, unlike the outer cover pushing method which directly affected roller alignment and nip pressure.
Solution Approach 2:
Instead of pushing the hook from the outside (outer cover method), the auxiliary pressing member presses the hook from the inside, applying force in the opposite direction. This inverted approach allows for more precise control of the engagement force and prevents the transmission of harmful forces to the roller system, thereby maintaining proper nip pressure and sheet conveying reliability.
3Device complexity
If the hook engagement mechanism is simplified, then the device complexity is reduced, but the engagement reliability deteriorates
Solution Approach 1:
The auxiliary pressing member is designed to perform multiple functions: it reinforces hook engagement, maintains proper positioning, and prevents over-pressing. This multi-functionality allows a single component to address multiple engagement requirements without adding significant complexity to the overall mechanism, thereby improving reliability without proportionally increasing device complexity.
Solution Approach 2:
The spring mechanism automatically engages the hook with the boss without requiring external actuation, and the auxiliary pressing member is positioned to automatically apply reinforcement pressure once engagement occurs. This self-service capability ensures reliable engagement through the inherent mechanical interactions of the components, reducing the need for complex control systems while maintaining high engagement reliability.
Data Source
AI summary
An image forming apparatus includes a conveying unit, a boss, a hook member and an auxiliary pressing member. The conveying unit is provided at an apparatus main body in a turnable manner and configured to form or open a nip area. The boss is provided at the apparatus main body. The hook member is provided at the conveying unit in a turnable manner and configured to be engaged with the boss when the conveying unit is turned to a position where the nip area is formed. The auxiliary pressing member is configured to press the hook member in a direction in which the hook member is engaged with the boss after the hook member is engaged with the boss. A direction in which the auxiliary pressing member presses the hook member is different from a turning direction of the conveying unit.