Feed Roller Timing Coordination for Paper Jam Prevention
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Solution Overview
Problem
In feed apparatuses with contact-separating mechanisms, there is a risk of paper jams when sheets are fed obliquely downward, as the feed roller may separate from the sheet before the stopper moves to a retracted position, causing the sheet to contact the stopper and leading to jamming issues.
Innovation Solution
A feed apparatus design that includes a swingable arm supporting the feed roller, a guide unit with a movable member that shifts between protruding and retracted positions, and a contact-separating mechanism that ensures the feed roller abuts the sheet only after the movable member is retracted, preventing sheet contact with the stopper and minimizing paper jams.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the feed roller is separated from the sheet using a contact-separating mechanism, then foreign matter adhesion to the sheet is prevented, but the sheet may contact the stopper and cause paper jams when fed obliquely downward
Solution Approach 1:
The movable member is advanced to the protruding position in advance (before sheet feeding begins) to preemptively prevent sheet contact with the stopper. This preliminary positioning ensures that when the feed roller separates from the sheet, the stopper is already in the safe retracted position, eliminating the risk of paper jams while maintaining foreign matter prevention benefits.
Solution Approach 2:
The system uses dynamic coordination between the movable member and feed roller through coupled driving mechanisms. The movable member's position is dynamically adjusted based on the feeding state - protruding when the feed roller separates (non-feeding state) and retracting when the feed roller contacts the sheet (feeding state), creating a dynamic safety mechanism that adapts to operational conditions.
2Manufacturing precision
If the stopper is positioned at the regulation position to prevent sheet movement, then sheet position control is improved, but the sheet may contact the stopper and cause jams when the feed roller separates early
Solution Approach 1:
The movable member is positioned to protrude in advance before sheet feeding occurs, creating a safety buffer that prevents sheet contact with the stopper during the critical separation phase of the feed roller. This preliminary safety positioning allows the stopper to remain at the regulation position for precise sheet control while eliminating the jam risk.
Solution Approach 2:
The movable member acts as an intermediary safety element between the sheet and the stopper. When the feed roller separates from the sheet, the movable member protrudes to intercept the sheet before it can contact the stopper, serving as a mediator that prevents direct sheet-stopper contact while allowing the stopper to maintain its position control function.
3Productivity
If the feed roller rotates in the feed direction to feed the sheet, then sheet feeding function is achieved, but the feed roller may abut the sheet before the stopper retracts causing jams
Solution Approach 1:
The movable member is advanced to the protruding position before the feed roller begins rotating to feed the sheet. This preliminary safety positioning ensures that when the feed roller contacts the sheet and begins feeding, the movable member is already in the safe retracted position, preventing any potential sheet contact with the stopper while maintaining efficient sheet feeding operation.
Solution Approach 2:
The coupled driving mechanism provides feedback control where the feed roller's rotation state controls the movable member's position. When the feed roller rotates in the feed direction, the system feedbacks to retract the movable member, ensuring coordination between feeding action and safety positioning to prevent jams while maintaining feeding efficiency.
Data Source
AI summary
There is provided a feed apparatus including a support unit; a feed roller; a swingable arm to support the feed roller; a guide unit; a movable member movable to a retracted position and a protruding position at which the movable member can abut against the sheet supported by the support unit; a driving source; driving transmission units; and a contact-separating mechanism to move the feed roller to a separated position and an abutment position at which the feed roller abuts against the sheet supported by the support unit. In a state in which the movable member is the protruding position and the feed roller is the separated position, a time required to start feeding of the sheet by the feed roller moved from the separated position to the abutment position is longer than a time required to shift the movable member from the protruding position to the retracted position.