Duplex Sheet Conveyance Control for Wet-Ink Jam Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing ink-jet image forming apparatuses face challenges in efficiently conveying and ejecting sheets with images on both sides, particularly when double-sided printing is required, as conventional methods can lead to increased sheet jamming due to ink wetness and require lengthy conveyance routes.
Innovation Solution
The system employs a controller to manage two conveyance manners: one for odd-numbered pages on the front side followed by even-numbered pages on the back side, and vice versa, allowing sheets to be conveyed and ejected through a simplified path, reducing the need for complex turn-over routes and minimizing sheet jamming.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional conveyance methods are used for double-sided printing, then sheets can be conveyed and turned over, but sheet jamming increases due to ink wetness and conveyance routes become lengthy
Solution Approach 1:
The patent inverts the conventional conveyance approach by ejecting sheets face-down instead of face-up. This allows the sheet to be conveyed from the image forming apparatus to the sheet conveyance device with the printed side facing downward, reducing the risk of sheet jamming due to ink wetness. The sheet is then turned over in the sheet conveyance device and ejected with the front side facing upward, achieving reliable double-sided printing conveyance.
Solution Approach 2:
The patent segments the conveyance process into two distinct phases: (1) conveyance from the image forming apparatus to the sheet conveyance device, and (2) conveyance within the sheet conveyance device for turning over and ejection. This segmentation allows each phase to be optimized independently, reducing overall conveyance route complexity and improving reliability.
2Productivity
If sheets are conveyed and turned over for double-sided printing, then both sides can be printed, but productivity decreases due to lengthy conveyance routes
Solution Approach 1:
By inverting the ejection orientation to face-down, the patent eliminates the need for complex mid-conveyance turning operations that increase conveyance time. The sheet is conveyed directly to the sheet conveyance device and then turned over once for ejection, significantly reducing the total conveyance route length and improving double-sided printing productivity.
3Ease of operation
If conventional ejection methods are used, then sheets are ejected face-up, but this causes sheet jamming when sheets are wet with ink
Solution Approach 1:
The patent inverts the conventional ejection orientation by ejecting sheets face-down from the image forming apparatus. This allows the printed side to face downward during conveyance, preventing sheet jamming caused by ink wetness. The sheet is then turned over in the sheet conveyance device and ejected with the front side facing upward, maintaining ease of operation while improving reliability.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The controller (68) conducts either one of: a first conveyance manner to allow the image forming apparatus (2) 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 (2) 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.