Post-Processing Clear Fluid Application for Archival Curl Mitigation

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Aqueous inkjet printing technologies face challenges with undesirable archival curl formation in uncoated image receiving media substrates, leading to handling difficulties and post-processing issues, particularly when curl is uneven across different substrates.

Innovation Solution

A post-processing scheme involving the selective application of a clear fluid onto imaged substrates, specifically on the non-image side, to counteract long-term archival curl by causing equal irreversible shrinkage on both sides of the substrate, thereby canceling out curl formation mechanisms.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If aqueous inks are used to print on uncoated image receiving media substrates, then substrate compatibility and printing flexibility are improved, but archival curl formation increases causing handling difficulties

Engineering Contradiction:

Improvesubstrate compatibilityVSAvoidhandling ease

Core Design Contradiction:

Adaptability or versatilityVSEase of operation

Solution Approach 1:

The patent applies a counteracting force to the curl formation mechanism by applying moisture to the non-image areas of the substrate. The aqueous ink deposited on the substrate causes differential moisture absorption between image and non-image areas, creating curl. By applying additional moisture to non-image areas through a post-processing module, the patent creates a counterbalancing effect that prevents the substrate from curling, thereby maintaining handling ease while using aqueous inks on uncoated substrates

Inventive Principle:

Principle #9Preliminary anti-action

2Stability of the object's composition

If aqueous inks with humectants are used, then ink stability and prevention of rapid drying are improved, but curl-inducing effects are enhanced

Engineering Contradiction:

Improveink stabilityVSAvoidcurl-inducing effect

Core Design Contradiction:

Stability of the object's compositionVSObject-generated harmful factors

Solution Approach 1:

The patent applies moisture selectively to non-image areas of the substrate rather than uniformly across the entire surface. The post-processing module detects image boundaries and applies counteracting moisture only to areas outside the printed regions. This local application strategy maintains the beneficial humectant properties of the aqueous ink in the image areas while creating a counterbalancing moisture effect in non-image areas to prevent curling

Inventive Principle:

Principle #3Local quality

3Adaptability or versatility

If wider latitude of substrate compositions is used, then user customization and design flexibility are improved, but post-processing errors and image quality reductions increase

Engineering Contradiction:

Improvesubstrate composition latitudeVSAvoidimage quality

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent introduces a post-processing module as an intermediary between the printing process and downstream finishing operations. This module acts as a mediator that detects and corrects curl formation in real-time by applying counteracting moisture to non-image areas. The intermediary function allows the system to maintain high image quality across diverse substrate compositions by actively compensating for variations in substrate behavior during and after printing

Inventive Principle:

Principle #24Intermediary (Mediator)

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

The method effectively mitigates archival curl formation, ensuring stable sheet handling and maintaining image quality by applying a clear fluid, such as water or a water/humectant mix, to the backside of printed substrates, which can be done in an off-line post-processing module, reducing the burden on the image forming device and improving downstream processing.

Implementation Method 1

to counteract long-term archival curl by causing equal irreversible shrinkage on both sides of the substrate

Methodology Applied

Scientific EffectIrreversible shrinkage: Deformation

Implementation Method 2

Humectants are a class of hygroscopic substances that are generally employed to keep things moist... Humectants attract and retain moisture

Methodology Applied

Scientific EffectHumectant action: Absorption (physical)

Data Source

PatentUS9956789B2Systems and methods for implementing a post-processing scheme for minimizing curl in sets of output image receiving media substrates imaged in image forming devices

Publication Date: 2018.05.01 XEROX CORP

AI summary

A system and method are provided for controlling archival sheet curl formation in image receiving media substrates on which images are formed using aqueous inks as the marking material. Archival curl occurs over time and is based on a partial coverage of the image receiving media substrates by the deposited water-based marking materials. A unique post-processing scheme applies selective aqueous clear fluid onto imaged substrates (cut sheets) to substantially counteract long-term archival curl formation in the individual image receiving media substrates. Both opposing sides of the cut sheet are processed in a manner that causes them to substantially equally undergo the generally irreversible shrinkage phenomenon that leads to archival curl, thus substantially canceling out the archival curl formation mechanism. A clear fluid is applied image-wise to portions of one or both sides of the image receiving media substrates to counterbalance the formed aqueous ink image.