Duplex Sheet Conveyance for Wet-Ink Jam-Free Ejection
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Solution Overview
Problem
Existing ink-jet image forming apparatuses face challenges in efficiently handling double-sided printing and sheet ejection, particularly in maintaining high productivity and preventing sheet jams due to ink wetness, especially when both sides of the sheet are printed.
Innovation Solution
The system employs a controller to manage two conveyance manners: one for single-sided printing and another for double-sided printing, allowing the image forming apparatus to form images on the front and back sides of a sheet sequentially and then convey the sheet through optimized paths in the sheet conveyance device to achieve face-up or face-down ejection, reducing the need for sheet turnover and shortening the conveyance route for double-sided printing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sheet is conveyed through a long path after both sides are printed, then the sheet can be ejected, but sheet jams occur due to ink wetness
Solution Approach 1:
The patent applies the skipping principle by rapidly conveying the sheet through the conveyance path immediately after double-sided printing is completed. The sheet is quickly transported from the printing position to the ejection position without lingering in the conveyance path, thereby reducing the time during which the ink-wet sheet could cause jams. This rushed conveyance minimizes exposure time to harmful conditions.
2Manufacturing precision
If the sheet is turned over multiple times for double-sided printing, then both sides can be printed, but productivity decreases
Solution Approach 1:
The patent applies preliminary action by pre-positioning the sheet in an orientation that minimizes the number of turnover operations needed for double-sided printing. The sheet is fed and oriented in advance such that both front and back sides can be printed with minimal repositioning, thereby reducing the total cycle time and improving productivity while maintaining printing quality.
Solution Approach 2:
The patent inverts the conventional printing sequence by printing the back side of the sheet before the front side in certain configurations. This reversed approach allows the sheet to be conveyed in a more direct path with fewer turnovers, thereby improving throughput while still achieving complete double-sided printing coverage.
3Volume of moving object
If the sheet is conveyed face-down for ejection, then space is saved, but the upward facing side must be turned over
Solution Approach 1:
The patent applies dynamics by making the sheet ejection orientation adjustable and adaptable based on the printing mode. The system can dynamically switch between face-up and face-down ejection configurations, and the sheet turnover mechanism is activated only when necessary. This dynamic adaptability allows space optimization in double-sided mode while maintaining operational flexibility.
Data Source
AI summary
The controller conducts either one of: a first conveyance manner to allow the image forming apparatus to form an image of an N-th page on the upward facing front side of the sheet and then form an image of an (N+1)-th page on the upward facing back side of the sheet after being turned over and conveyed the sheet, with the front side having the image of the N-th page facing downward, to be ejected; and a second conveyance manner to allow the image forming apparatus to form the image of the (N+1)-th page on the upward facing front side of the sheet and then form the image of the N-th page on the upward facing back side of the sheet after being turned over and conveyed the sheet, with the back side having the image of the N-th page facing upward, to be ejected.