Sheet Stacking Apparatus Abutting Portion Friction Reduction
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Solution Overview
Problem
Existing sheet stacking apparatuses in image forming systems face issues with noise and damage to sheets due to friction between the trailing end of sheets and fixed abutting portions during the lifting and lowering of the stacking tray.
Innovation Solution
A sheet stacking apparatus with a first abutting portion that remains stationary and a second abutting portion supported by the first to move in the up-down direction, allowing the second abutting portion to adjust its movement in sync with the stacking portion, preventing friction when the tray is lowered beyond a certain point.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the stacking portion is lifted and lowered with sheets supported thereon, then the sheet stacking apparatus can accommodate varying sheet volumes, but the trailing end of the sheets rubs against the sheet abutting portion causing noise and damage
Solution Approach 1:
The sheet abutting portion is changed from a fixed structure to a movable one that follows the trailing end of the sheets during tray lifting and lowering operations. This dynamic configuration allows the abutting portion to move synchronously with the sheet position, eliminating friction and damage while maintaining adaptability to varying sheet volumes
Solution Approach 2:
A belt member is introduced as an intermediary element between the fixed casing and the movable tray. The belt member transmits the movement of the tray to the sheet abutting portion, enabling the abutting portion to follow the sheet trailing end without being directly connected to the moving tray, thus reducing noise and damage
2Object-affected harmful factors
If a belt member is used to abut the trailing end of sheets and rotate with tray movement, then sheet rubbing is reduced, but the belt member moves in accordance with the discharge tray irrespective of the discharge tray position causing unnecessary movement
Solution Approach 1:
The sheet abutting portion is positioned to preliminarily follow the sheet trailing end before the tray reaches positions where rubbing would occur. By anticipating the sheet position and adjusting the abutting portion accordingly, the system prevents rubbing without requiring the belt member to move throughout the entire tray range
Solution Approach 2:
The movable sheet abutting portion is implemented only at the specific location where sheet trailing end contact occurs, while other parts of the discharge unit remain fixed. This localized mobility reduces unnecessary movement and simplifies the overall device structure compared to making the entire tray system dynamically adjustable
Data Source
AI summary
A sheet stacking apparatus includes a discharge unit, a stacking portion on which discharged sheets are stacked, a lifting unit, and first and second abutting portions. The lifting unit lifts and lowers the stacking portion. The first abutting portion abuts a trailing end of the stacked sheets in a sheet discharge direction. The first abutting portion does not move in an up-down direction. The second abutting portion abuts the stacked sheets trailing end. The first abutting portion supports the second abutting portion such that the second abutting portion is movable in the up-down direction. If the stacking portion is lowered from a first to a second position below the first position, the second abutting portion does not move in accordance with the stacking portion. If the stacking portion is further lowered beyond the second position, the second abutting portion moves in accordance with the stacking portion.