Sheet Feeding Apparatus Lateral Cam Mechanism
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Solution Overview
Problem
In image forming apparatuses, the miniaturization of sheet feeding apparatuses is hindered by the need for a cam coaxial with the feed roller, which limits the reduction in size due to a tradeoff between cam size and pivot angle, resulting in frequent sheet replenishment and reduced ease of operation.
Innovation Solution
A sheet feeding apparatus that lifts and lowers the sheet supporting member without a coaxial cam, using a cam follower with a curved cam surface and a slider to change contact states, allowing the sheet supporting member to move between feed and retracted positions, thereby reducing the size of the cam and improving operational efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a cam is provided coaxial with the feed roller to lift and lower the sheet supporting member, then the sheet supporting member can be moved reliably, but the cam size cannot be reduced due to the tradeoff between cam size and pivot angle
Solution Approach 1:
The invention moves the cam mechanism from a coaxial arrangement with the feed roller to a lateral arrangement where the cam is positioned beside the feed roller. This dimensional change allows the cam to operate in a different spatial plane, eliminating the size constraints imposed by the coaxial configuration while maintaining reliable actuation of the sheet supporting member.
Solution Approach 2:
The invention introduces a cam follower as an intermediary element that translates the cam's rotational motion into vertical movement of the sheet supporting member. This intermediary mechanism allows the cam to be smaller while still achieving the required lift and lower actions through the follower's engagement with the cam surface.
2Volume of moving object
If the cam size is reduced, then the apparatus can be miniaturized, but the pivot angle of the sheet supporting member becomes small and the distance between feed roller and sheet supporting member is reduced
Solution Approach 1:
By repositioning the cam laterally rather than coaxially, the invention creates additional spatial freedom that allows the sheet supporting member to achieve sufficient distance from the feed roller even with a smaller cam. The lateral arrangement provides a longer lever arm for the lift plate, compensating for the reduced cam dimensions.
3Volume of moving object
If the distance between feed roller and sheet supporting member is reduced, then the cam can be smaller, but the amount of sheets stacked on the sheet supporting member becomes small
Solution Approach 1:
The lateral repositioning of the cam creates additional vertical space between the feed roller and sheet supporting member, allowing for a greater stack height of sheets. This dimensional rearrangement decouples the cam size from the sheet stacking capacity, enabling both small cam size and large sheet capacity to coexist.
Data Source
AI summary
A feeding apparatus includes a sheet supporting member, a feeding member, and a lift unit. The lift unit lifts and lowers the sheet supporting member to abut a sheet stacked on the sheet supporting member against the feeding member. The lift unit includes an urging member that biases the sheet supporting member towards the feeding member, a moving member that moves in a first direction different from a sheet supporting member lifting direction, and a contact member in contact with the moving member. The contact member includes a curved cam surface in a region that comes in contact with the moving member. A contact state between the moving member and the contact member is changed by moving the moving member in the first direction and the curved cam surface. Regarding changing the contact state, the sheet supporting member can be moved to a feed position and a retracted position.