Inkjet recording method

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Solution Overview

Problem

Inkjet textile printing on fabrics containing polyester faces challenges with white ink bleeding, low adhesiveness, and high stickiness, leading to poor image quality and abrasion resistance.

Innovation Solution

The method involves applying a pretreatment liquid followed by two layers of white ink and one layer of color ink using an inkjet and WOW (Wet On Wet) method, with specific formulations for the inks including polymers with carbodiimide or oxazoline groups and urethane resins to enhance adhesiveness and reduce stickiness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If white ink is applied to fabric containing polyester, then the fabric can be printed, but the white ink bleeds through the fabric resulting in poor white concealing properties

Engineering Contradiction:
Improvewhite concealing propertiesVSAvoidink bleed-through
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The white ink application is divided into multiple sequential layers (first white ink layer, second white ink layer, and optionally third white ink layer) rather than applying a single thick layer. Each layer is applied at controlled densities to progressively build up white concealing properties while preventing bleed-through to the fabric backside.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The solution adds a dimensional aspect by applying ink layers in the thickness dimension (z-direction) rather than increasing the area coverage. Multiple thin layers are stacked vertically to achieve sufficient opacity and concealing properties without excessive single-layer application that causes bleed-through.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Reliability

If white ink is applied to fabric containing polyester, then the fabric can be printed, but the ink layer detaches due to low adhesiveness resulting in poor abrasion resistance

Engineering Contradiction:
Improveabrasion resistanceVSAvoidadhesiveness of white ink layer
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

A pretreatment liquid is applied to the fabric before applying the white ink layers. This preliminary action modifies the fabric surface to enhance its adhesion properties, creating a better bonding surface for the subsequent white ink application and preventing ink layer detachment during abrasion.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The white ink formulation uses composite material composition including specific polymer resins (acrylic resin, vinyl resin, or polyester resin) with controlled glass transition temperatures and molecular weights. This composite approach creates an ink layer with enhanced intrinsic adhesiveness to polyester fabric that resists detachment under abrasion.

Inventive Principle:
Principle #40Composite materials

3Manufacturing precision

If white ink is applied to fabric, then the image can be formed, but the image portion becomes sticky affecting handle and comfort

Engineering Contradiction:
Improveimage qualityVSAvoidstickiness of image portion
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The white ink formulation carefully controls the glass transition temperature (Tg) of the polymer resin within a specific range (−50°C to 0°C) and limits the hydroxyl group content to 0.5 mmol/g or less. These parameter changes reduce the stickiness of the cured ink layer while maintaining adequate adhesiveness and image quality.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The ink formulation uses localized functional groups and additives specifically targeted at reducing stickiness in the image portion without compromising overall adhesion. The polymer resin structure is designed with specific functional characteristics that provide non-sticky surface properties while maintaining bonding strength to the fabric.

Inventive Principle:
Principle #3Local quality

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 results in high white concealing properties, improved abrasion resistance, and reduced stickiness of the image on the fabric, enhancing the overall quality of the printed matter.

Implementation Method 1

An inkjet recording method is a recording method in which ink droplets are discharged from fine nozzles and deposited on a recording medium to form characters and images

Methodology Applied
Scientific EffectInkjet droplet discharge:

Implementation Method 2

applying a first white ink by an inkjet method and a WOW method onto an application region of the pretreatment liquid obtained in the applying of the pretreatment liquid, to form an image

Methodology Applied
Scientific EffectWet-on-wet deposition:

Data Source

PatentEP4335652A1Inkjet recording method
Publication Date: 2024.03.13 RICOH CO LTD
  • EP4335652A1 patent drawingFigure 1~2
  • EP4335652A1 patent drawingFigure 3
  • EP4335652A1 patent drawing

AI summary

An inkjet recording method is provided that includes the following steps: applying a pretreatment liquid to a fabric; applying a first white ink by an inkjet method and a wet on wet method onto an application region of the pretreatment liquid obtained in the applying of the pretreatment liquid, to form an image; applying a second white ink by an inkjet method and a wet on wet method onto the image formed in the applying of the first white ink; and applying a color ink by an inkjet method and a wet on wet method onto an image obtained in the applying of the second white ink.