Primer Composition for Offset Media Inkjet Compatibility

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Solution Overview

Problem

Inkjet printing on offset media surfaces results in poor image quality, slow drying, and low durability due to the hydrophobic and nonporous nature of these surfaces, which are not well-suited for water-based inks, leading to issues with smearfastness and compatibility.

Innovation Solution

A primer composition is applied to the media substrate, comprising polyvinyl alcohol, starch nanoparticles, polymer latex dispersion, wax, and cationic salt, which enhances the interaction with water-based inks, improving both dry and wet smearfastness and allowing for high-speed printing without compromising print quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If offset coated paper with hydrophobic polymer coating is used for inkjet printing, then the media is suitable for conventional offset printing, but water-based inks exhibit poor image quality, slow drying, and poor durability

Engineering Contradiction:
Improveimage durabilityVSAvoidink compatibility
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

A primer composition is applied as an intermediary layer between the offset coated paper and water-based inks. The primer contains hydrophilic polymers (polyvinyl alcohol, carboxymethyl cellulose) that attract and bind water-based inks, while also adhering to the hydrophobic offset coating. This intermediary layer enables compatibility between the ink and substrate without requiring changes to either the paper or ink formulation.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The primer composition changes the surface properties of the offset coated paper by introducing hydrophilic functional groups and modifying surface energy characteristics. This parameter change transforms the surface from hydrophobic to hydrophilic, enabling proper wetting and absorption of water-based inks while maintaining the original offset printing suitability.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If high speed printing is implemented on offset media, then productivity increases, but image quality and drying performance deteriorate

Engineering Contradiction:
Improveprinting speedVSAvoidimage quality
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The primer layer is applied in advance to the offset coated paper before printing. This preliminary action prepares the surface with optimal properties for water-based ink reception, ensuring that even at high printing speeds, the ink will properly wet, adhere, and dry on the surface without compromising image quality.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The primer acts as a mediator that enables high-speed printing by creating a surface that rapidly accepts and secures water-based inks. The hydrophilic polymers in the primer quickly bind the ink, reducing drying time and allowing maintain high printing speeds without sacrificing image quality.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of manufacture

If smooth nonporous surface coating is applied to offset paper, then offset printing performance is acceptable, but inkjet ink penetration and drying are impaired

Engineering Contradiction:
Improveoffset printing suitabilityVSAvoiddrying time
Core Design Contradiction:
Ease of manufactureVSDuration of action of moving object

Solution Approach 1:

The primer composition introduces local quality changes to the offset coated paper surface by creating regions with different functional properties. The primer contains hydrophilic polymers that create ink-receptive zones on the otherwise hydrophobic surface, allowing localized ink penetration and drying without affecting the overall smooth nonporous structure needed for offset printing.

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

The primer composition significantly enhances the durability and smear resistance of printed images, enabling immediate dry and wet smearfastness, thus preventing smearing during rewinding and allowing high-speed printing without additional drying time or increased space requirements.

Implementation Method 1

The primer compositions can be applied to a media substrate, such as an offset media substrate, to improve the ability of the substrate to receive water-based inks

Methodology Applied
Scientific EffectHydrophilic interaction: Hydrophile

Implementation Method 2

After the printed image is picked up from the impression cylinder and placed on the delivery cylinder, the printed sheet passes through a drying section

Methodology Applied
Scientific EffectEvaporation: Evaporation

Data Source

PatentEP3265318B1Primer compositions
Publication Date: 2019.10.02 HEWLETT PACKARD DEVELOPMENT COMPANY LP
  • EP3265318B1 patent drawingFigure 1~2
  • EP3265318B1 patent drawingFigure 3

AI summary

The present disclosure is drawn to primer compositions which can include a binder including polyvinyl alcohol, starch nanoparticles, and a polymer latex dispersion. The primer competitions can also include a wax, a cationic salt, and water.