Duplex Printing Order Reversal for Sheet Deformation Control
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Solution Overview
Problem
In duplex printing, sheets often deform due to treatments like ink application and curing, leading to compromised print quality or collisions with the print head, resulting in wasted material and reduced productivity as entire sheets must be discarded when one is damaged.
Innovation Solution
A method that estimates the likelihood of sheet damage during the first image printing and compares it to a threshold, reversing the print order if the likelihood exceeds the threshold to ensure the second image is printed first, minimizing damage risks and maintaining productivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the first image is printed first on the front side of the sheet, then the print process can proceed in conventional order, but the sheet may become deformed due to ink application and curing treatments, compromising later print quality or causing collision with the print head
Solution Approach 1:
The patent applies inversion by reversing the conventional print order: instead of printing the first image on the front side first, the system prints the second image on the back side first, then prints the first image on the front side. This reversal ensures that the sheet is not deformed after the first image printing, as the sheet will not be returned to the print station for further processing after the first image is printed.
2Manufacturing precision
If a damaged sheet is detected in the duplex path, then the defective sheet can be discarded, but all subsequent sheets in the duplex path must also be discarded and the print process aborted until the duplex path is emptied
Solution Approach 1:
The patent applies preliminary action by estimating the likelihood of sheet damage before the print process begins. The system calculates a damage likelihood value based on factors such as ink coverage, media type, and environmental conditions, and compares it to a threshold. If the likelihood exceeds the threshold, the system proactively reverses the print order to prevent damage before it occurs, rather than detecting and responding to damage after it has happened.
3Reliability
If the print order is reversed to print the second image first, then sheet damage risk is reduced, but the conventional page order must be preserved requiring additional sheet handling
Solution Approach 1:
The patent applies feedback by continuously monitoring the damage likelihood and adjusting the print order dynamically. The system estimates the damage likelihood for each sheet based on real-time factors such as ink coverage, media properties, and environmental conditions. If the likelihood exceeds a threshold, the system reverses the print order for that specific sheet; otherwise, it maintains the conventional order. This feedback mechanism allows the system to adapt to varying conditions and minimize damage while managing sheet handling complexity.
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 approach reduces material waste and maintains high productivity by prioritizing the printing of the second image when damage is likely, ensuring the first image is printed last and avoiding deformation-related issues, thus preserving page order and print quality.
Implementation Method 1
the media sheets are wetted when liquid ink is applied
Implementation Method 2
the media sheets are wetted when liquid ink is applied and are then subjected to heat or radiation in order to cure the ink and to dry the sheet
Implementation Method 3
These treatments may cause the sheet to develop an out-of-plane deformation by e.g. warping or deforming
Implementation Method 4
the media sheets are wetted when liquid ink is applied and are then subjected to heat or radiation in order to cure the ink
Data Source
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Figure 3
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AI summary
A method of duplex printing on a cut sheet printer having a sheet supply system for feeding sheets to a print station in a first orientation for printing a first image on the first side of the sheet and then in a second orientation for printing a second image on a second side of the sheet. The following steps are performed for each sheet: (a) estimating a likelihood P1 that, in a print process for printing the first image, the sheet will become damaged to such an extent that the damage will compromise a later print process for printing the second image; (b) comparing the likelihood P1 to a threshold T; and (c) if the likelihood P1 exceeds the threshold T, reversing the print order so that the second image is printed before the first image. The invention ensures that the riskier image is printed on the duplex pass. The chances of the sheet with the simplex image then successfully passing through the duplex pass are then increased.