Duplex Printing Long Sheets Using Segmented Transport Paths
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Solution Overview
Problem
Conventional image forming devices face limitations in duplex printing of long paper sheets, as the reversed paper sheet often collides with itself due to insufficient reverse transport path length, restricting the maximum sheet length that can be printed.
Innovation Solution
The image forming device incorporates a sheet transport path with a first discharge port, a second discharge port, and a controller that controls switchers to temporarily discharge one end of the paper sheet and reverse the other end, allowing it to be transported back for printing, thereby eliminating length limitations by using a third transport path to facilitate duplex printing of long sheets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a conventional reverse transport path configuration is used, then the device structure is simple, but the paper sheet length is limited because the reversed sheet collides with itself
Solution Approach 1:
The transport path is segmented into multiple independent sections: a first transport path for forward movement, a second transport path for reversed discharge, and a third transport path for returning the sheet. This segmentation allows each path to be optimized independently, enabling long sheets to be transported without self-collision while maintaining manageable device complexity through modular path design.
Solution Approach 2:
The invention introduces a multi-dimensional transport architecture by adding discharge paths in different spatial directions. The first discharge port discharges sheets in the forward direction, while the second discharge port discharges reversed sheets in the opposite direction. This dimensional expansion of the transport path allows long paper sheets to be routed around the device rather than colliding with themselves during reversal.
2Volume of moving object
If the paper sheet is reversed inside the main body for duplex printing, then the device structure is compact, but long sheets collide with themselves and cannot be advanced
Solution Approach 1:
The invention introduces discharge ports and switchers as intermediary elements between the image former and the transport paths. These intermediaries enable the paper sheet to be temporarily discharged outside the main device body during the reversal process, preventing self-collision. The switchers act as controllable intermediaries that redirect the sheet flow, allowing long sheets to navigate the transport system without interference while maintaining a compact overall device footprint.
3Ease of operation
If a simple transport path is used, then the device is easy to operate, but duplex printing of long sheets is not possible
Solution Approach 1:
The transport system is designed with multi-functionality to handle both simple and complex printing requirements. The first and second discharge ports can serve different functions: the first for standard single-sided printing, and the second for duplex printing of long sheets. The switchers provide universal control capability, automatically routing sheets based on the printing mode. This multi-functional design maintains ease of operation while enabling versatile duplex printing capabilities for various sheet lengths.
Data Source
AI summary
This image forming device includes an image former, a fuser, a sheet transport path that transports a paper sheet to the image former and the fuser, first and second discharge ports that are connected to the sheet transport path so as to enable a paper sheet on which a toner image has been fused to be discharged to the outside, and a controller. The sheet transport path includes first to third transport paths, and a first and second switcher. The controller, in the case of duplex printing, controls the first and second switchers such that a one end side of the paper sheet is transported to the second discharge port, and controls the second switcher such that, when the one end side is being discharged from the second discharge port, reverses the paper sheet and causes the another end side to be transported toward the image former.