Conveyor Sheet Pulling Prevention via Idle Rollers
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Solution Overview
Problem
In image forming apparatuses, large-size sheets experience sheet pulling between upstream and downstream rollers during conveyance, leading to surface scratches and image quality deterioration, particularly with high-rigidity sheets like thick paper.
Innovation Solution
The conveyor system includes upstream and downstream conveyance members that idle in opposite directions during sheet conveyance, preventing sheet pulling by synchronizing their rotation with the sheet conveyance direction to maintain nip integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the conveyance of the sheet is stopped and resumed by multiple pairs of rollers, then the sheet can be conveyed to the desired position, but the sheet may be pulled between the rollers causing surface scratches and image quality deterioration
Solution Approach 1:
The patent applies preliminary action by having the downstream rollers stop rotating before the upstream rollers stop rotating. This sequential stopping prevents the sheet from being pulled between rollers during conveyance resumption, eliminating surface scratches and slip marks while maintaining precise sheet positioning control
2Manufacturing precision
If multiple pairs of rollers are used for large-size sheet conveyance, then the sheet can be conveyed accurately, but the timing of stop and resume rotation may shift between rollers causing sheet pulling
Solution Approach 1:
The patent implements preliminary action through sequential control where downstream rollers stop rotating before upstream rollers. This time-ordered stopping sequence ensures conveyance stability by preventing timing shifts between rollers, while maintaining accurate sheet conveyance position through coordinated roller operation
3Loss of time
If the sheet conveyance is stopped and resumed, then the sheet can be positioned at the desired timing, but the sheet may slip and slip marks may remain on the image
Solution Approach 1:
The patent applies preliminary action by having downstream rollers stop before upstream rollers stop. This sequential stopping prevents sheet slipping during conveyance resumption, eliminating slip marks on the image while maintaining precise timing control for sheet conveyance to the desired position
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 solution effectively prevents sheet pulling and subsequent surface damage, enhancing image quality by ensuring synchronized rotation of conveyance members during sheet conveyance.
Implementation Method 1
a pair of upstream conveyance members (11A, 11B) and a pair of downstream conveyance members (12A, 12B) to rotate in directions indicated by arrows in FIG. 3. The upstream conveyance members (11A, 11B) and the downstream conveyance members (12A, 12B) nipped a sheet P at corresponding one of a nip between the upstream conveyance members (11A, 11B) and a nip between the downstream conveyance members (12A, 12B), respectively
Data Source
Figure 1
Figure 2~3
Figure 4~5B
AI summary
A conveyor (10) includes a pair of upstream conveyance members and a pair of downstream conveyance members (12). The pair of upstream conveyance members (11) rotates to convey a sheet (P) while nipping a sheet (P) at a nip between the pair of upstream conveyance members. The pair of downstream conveyance members (12) disposed downstream from the pair of upstream conveyance members (11) in a sheet conveyance direction, rotates to convey a sheet (P) while nipping the sheet (P) at a nip between the pair of downstream conveyance members. One pair of the pair of upstream conveyance members (11) and the pair of downstream conveyance members (12) idle when the one pair of the pair of upstream conveyance members (11) and the pair of downstream conveyance members (12) rotates in a direction opposite to the sheet conveyance direction.