Sheet Feeding Mechanism Using Eccentric Cam for Longer Feed Distance
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Solution Overview
Problem
Conventional sheet feeding devices face issues where the feedable distance is limited, leading to failures in feeding sheets even when detected, due to the pulley's restriction of the separation pad position after the feed surface passage, causing inconveniences and inefficiencies.
Innovation Solution
The configuration eliminates the pulley and uses an eccentric cam and cam follower to determine the position of the sheet stacking tray, combined with a guide groove and support rib to restrict the separation pad's position, ensuring a longer feedable distance without interfering with the separation pad's function.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pulley is used to restrict the separation pad position after the feed surface passage, then the separation pad position is controlled, but the feedable distance is limited causing sheet feeding failures
Solution Approach 1:
The invention removes the pulley component that was previously used to restrict the separation pad position. Instead of using a pulley, the separation pad position is controlled through the interaction between the eccentric cam mechanism and the guide groove, which eliminates the limitation on feedable distance while maintaining separation pad position control
Solution Approach 2:
The invention introduces a guide groove as an intermediary element that works in conjunction with the eccentric cam mechanism to control the separation pad position. The guide groove receives the protruding portion of the separation pad holding mechanism, providing positional control without the need for a pulley, thereby enabling longer feedable distance
2Length of moving object
If the sheet stacking tray is positioned closer to the feed surface to extend feedable distance, then the feedable distance increases, but the separation pad function may be interfered with
Solution Approach 1:
The invention uses an eccentric cam mechanism that converts rotational motion into dynamic vertical movement of the sheet stacking tray. The eccentric cam, with its maximum eccentric radius larger than the feed surface radius, creates a dynamic positioning system that automatically adjusts the tray position during rotation, maintaining both extended feedable distance and proper separation pad function
Solution Approach 2:
The invention positions the sheet stacking tray at a standby position radially inward of the outer diameter of the feed surface before feeding begins. This preliminary positioning, combined with the eccentric cam mechanism, ensures that the tray is in the optimal position to provide maximum feedable distance while the separation pad is already in place to perform its separation function
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 design allows for a longer feedable distance, preventing sheet feeding failures and maintaining efficient operation even with compact designs, enhancing user satisfaction by ensuring detected sheets are reliably fed.
Implementation Method 1
The eccentric cam 53 is fixed to a rotating shaft of the sheet feed roller 41 and has a maximum eccentric radius larger than the radius of the sheet feed roller 41. The cam follower 55 is provided at a position in the sheet stacking tray 27 where the cam follower 55 contacts the eccentric cam 53 and raises the sheet stacking tray 27 by moving the contact point from a large-diameter portion of the eccentric cam 53 to a small-diameter portion of the eccentric cam 53 as the eccentric cam 53 rotates.
Data Source
AI summary
A sheet feeding device has a sheet stacking tray, a sheet stop portion, a sheet feed roller, a separation member, a first urging member, an eccentric cam, a cam follower, a sheet detection mechanism, and a holding mechanism. The holding mechanism holds the separation member at a position away from the sheet feed roller after a half-moon-shaped feed surface has passed across the separation member as the sheet feed roller rotates. Immediately before a sheet starts to be fed, the sheet stacking tray is kept on standby at a standby position radially inward of the outer diameter of the feed surface so that the feedable distance between the feed start position and the sheet stop portion is larger than the detectable distance as the maximum distance between the detectable position at which the sheet can be detected by the sheet detection mechanism and the sheet stop portion.