Elliptical Hold Down Finger for Paper Tray Misalignment
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Solution Overview
Problem
Finisher process trays in multifunction peripherals often cause misalignment of printed pages due to disturbance by newly ejected sheets, which can lead to incomplete or incorrect finishing tasks like stapling, as existing hold down mechanisms fail to effectively maintain page alignment during printing operations.
Innovation Solution
A retractable hold down finger mechanism that moves in a substantially elliptical path, coordinating with the paper accumulation tray's movement to prevent page disturbance, using a rack gear and cylindrical gear system to ensure the hold down finger retracts when the tray is unexpectedly moved, thus maintaining page alignment and preventing damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a hold down mechanism is used to maintain page alignment, then page misalignment is prevented, but the mechanism may interfere with the natural ejection and accumulation of printed pages
Solution Approach 1:
The hold down finger is designed to be movable rather than fixed, allowing it to dynamically adjust its position between an extended holding position and a retracted position. This enables the mechanism to maintain page alignment when needed while clearing the ejection path when pages are being deposited, resolving the contradiction between precision and ease of operation
Solution Approach 2:
The hold down finger extends to hold down the top sheet of paper in advance of the ejection event, preventing misalignment before it can occur. By performing this preliminary action, the system ensures pages remain aligned during the ejection and accumulation process without requiring continuous intervention
2Manufacturing precision
If the hold down finger remains in position to maintain alignment, then pages stay aligned, but newly ejected sheets may be disturbed or misaligned
Solution Approach 1:
The hold down finger operates periodically, extending to hold pages during accumulation and retracting to allow ejection. This rhythmic motion ensures that pages are held down only when needed for alignment, while clearing the path during ejection, thereby maintaining consistent alignment without disturbing newly ejected sheets
Solution Approach 2:
The finger's ability to move between extended and retracted states allows it to adapt to different operational phases, maintaining alignment reliability by being present during accumulation and absent during ejection, preventing the contradiction between maintaining alignment and avoiding disturbance
3Adaptability or versatility
If the paper accumulation tray moves during printing, then accommodation of printed pages is improved, but page alignment is disrupted
Solution Approach 1:
The hold down finger acts as a counterbalancing element that compensates for the disruption caused by tray movement. By maintaining downward pressure on the pages during tray motion, it counteracts the destabilizing effect of movement and preserves alignment despite the tray's adaptability-driven motion
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
The retractable hold down finger mechanism effectively prevents page misalignment and ensures accurate finishing operations by maintaining the top sheet's position, allowing for seamless integration with stapling and other finishing tasks without the need for manual correction or reprinting.
Implementation Method 1
using a rack gear and cylindrical gear system to ensure the hold down finger retracts when the tray is unexpectedly moved
Data Source
AI summary
A hold down finger for a finisher process tray contacts the top sheet of paper on a paper tray to prevent subsequently printed pages from disturbing pages disposed on the paper tray. The hold down finger includes gears that move a portion of the hold down finger that contacts the top sheet of paper from a retracted position to a forward hold down position along a substantially elliptical path. After each sheet is printed and placed on top of other pages in the paper tray, the paper tray lowers and the hold down finger continues along the substantially elliptical path back to the retracted position. A rack gear associated with the paper tray engages a cylindrical gear of the hold down finger to return the hold down finger to the retracted position if the paper tray is forced upwards while the hold down finger is in the forward position.