Letterbox Media Diverter for Fast Sheet Inversion
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Solution Overview
Problem
Existing diverter assemblies in xerographic printers face challenges with increasingly smaller inter-document gaps, leading to potential jams and inefficiencies as the gate's movement speed is limited, making it difficult to achieve faster operation with practical configurations.
Innovation Solution
A multi-position letterbox media diverter that operates as soon as the trailing edge of a sheet passes the fuser exit nip, allowing the letterbox gate to direct sheets into duplex paths and invert them quickly, while a lower baffle positions subsequent sheets for output, reducing the time in the inverter path and eliminating the need for additional guides.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the gate moves faster to reduce the inter-document gap, then the productivity is improved, but the gate may not reach the desired position before the second sheet arrives, causing jams
Solution Approach 1:
The gate is divided into multiple segments that can move independently. The upstream edge segment can be positioned separately from the downstream edge segment, allowing the upstream edge to clear the path earlier while the downstream edge maintains proper positioning. This segmentation enables the gate to effectively move faster without causing jams.
Solution Approach 2:
The upstream edge of the gate begins moving to clear the path before the second sheet arrives. By initiating the gate's movement earlier in the cycle, the system ensures that the diversion path is cleared in time for the next sheet, effectively reducing the required response time and preventing jams.
2Ease of operation
If the gate is positioned diagonally across the media transport path, then the sheet diversion is effective, but the sheet travel distance is increased
Solution Approach 1:
The gate transitions from a diagonal two-dimensional positioning to a more optimized configuration where the upstream edge can move independently. This dimensional change in the gate's movement capability allows for a more direct sheet path while maintaining effective diversion.
Solution Approach 2:
By segmenting the gate into upstream and downstream edges that can move independently, the system creates a more efficient sheet path. The upstream edge can clear earlier, allowing sheets to follow a shorter, more direct route through the diversion point.
3Manufacturing precision
If the gate moves slower to ensure proper positioning, then the sheet diversion accuracy is improved, but the inter-document gap increases, reducing productivity
Solution Approach 1:
The segmented gate design allows the upstream edge to move at a different speed and timing than the downstream edge. This enables the upstream edge to clear the path faster (improving productivity) while the downstream edge maintains precise positioning (maintaining accuracy).
Solution Approach 2:
The upstream edge performs preliminary action by moving to clear the path before the downstream edge completes its positioning. This preliminary movement allows the system to maintain smaller inter-document gaps while ensuring accurate sheet diversion when the downstream edge reaches its final position.
Data Source
AI summary
A 3-way letterbox media diverter directs and controls media in 2 forward directions and 1 reverse direction within a printer's paper path. The letterbox design enables actuation of the diverter from a first position to a second position just as the trail edge of a sheet passes a post fuser nip. Once the diverter reaches the second position, an invert nip now controlling the sheet is reversed to thereby invert the sheet. Thus, inversion of the sheet is accomplished in a small space envelope, time to reverse direction is reduced, process speed can be reduced and additional paper guides are eliminated.