Actuator Protrusion Cam Retraction for Image Forming Apparatus
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Solution Overview
Problem
In image forming apparatuses, the movement of image forming units from an interior to an exterior position can cause interference or collision with sheet detection actuators, leading to potential damage.
Innovation Solution
The apparatus incorporates a pivotally supported actuator with a protrusion that is urged upstream by a spring and maintained at a standby position by a cam and contact portion, which pivots to a retracted position as the unit moves, preventing collisions with photosensitive drums and rollers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the image forming unit is made movable between accommodated and shifted positions for maintenance access, then the ease of operation is improved, but the reliability deteriorates due to potential collision damage to the actuator protrusion
Solution Approach 1:
The cam mechanism performs preliminary action by automatically moving the actuator protrusion to a safe retracted position before the image forming unit reaches the shifted position, preventing collision damage before it can occur. The urging member (spring) pre-positions the protrusion upstream, and the cam timing ensures the protrusion is retracted in advance of potential contact with the image forming unit.
Solution Approach 2:
The cam acts as an intermediary mechanism between the image forming unit movement and the actuator protrusion positioning. It mediates the relationship by converting the linear movement of the image forming unit into rotational movement of the actuator, which then controls the protrusion position, preventing direct collision while maintaining functional coordination.
2Measurement precision
If the protrusion is positioned to cross the conveyance path for sheet detection, then the measurement precision is improved, but the object-generated harmful factors worsen due to potential interference with the image forming unit during movement
Solution Approach 1:
The actuator protrusion transitions from a static position to a dynamic, movable position. The urging member (spring) enables the protrusion to dynamically adjust its position between crossing the conveyance path (for detection) and retracting upstream (to avoid interference). This dynamic positioning allows the system to adapt between measurement and protection modes.
Solution Approach 2:
The cam mechanism performs preliminary action by automatically moving the actuator protrusion to a safe retracted position before the image forming unit reaches the shifted position, preventing collision damage before it can occur. The urging member (spring) pre-positions the protrusion upstream, and the cam timing ensures the protrusion is retracted in advance of potential contact with the image forming unit.
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 effectively prevents damage to the actuator protrusion during unit movement, ensuring reliable operation and maintaining image quality by avoiding interference with photosensitive drums and rollers.
Implementation Method 1
The urging member exerts an urging force to urge the protrusion upstream in the conveyance direction
Implementation Method 2
The contact portion and the cam are configured to, when the image forming unit is at the accommodated position, contact each other and maintain the protrusion at the standby position against the urging force of the urging member
Data Source
AI summary
An image forming apparatus includes a casing, an image forming unit movable between an accommodated position and a shifted position, an actuator, an urging member, a cam, and a contact portion. The actuator includes a pivot shaft and a protrusion protruding therefrom. The protrusion at a standby position crosses a conveyance path and is contactable with a sheet conveyed along the conveyance path. When the image forming unit is at the accommodated position, the contact portion and the cam contact each other and maintain the protrusion at the standby position against an urging force of the urging member. As the image forming unit moves from the accommodated position to the shifted position, the contact portion and the cam move away from each other such that the protrusion pivots from the standby position, by the urging force, to a retracted position at which the protrusion is retracted from the conveyance path.