Photocurable Silicone Ink for High-Definition Printing

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Solution Overview

Problem

Conventional inkjet printers using solvent ink face issues with atmosphere contamination due to organic solvents, fluidity problems leading to blurred images, and skin sensitization, while photocurable inks with (meth)acrylates have limitations in handling properties and optical curing speed.

Innovation Solution

A photocurable liquid ink containing a silicone compound with a specific chemical structure, which includes a photocurable liquid blended with a coloring agent and a silicone compound that undergoes chemical modification with epoxy groups, enhancing image quality and reducing odor and skin sensitivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If solvent ink is used in inkjet printers, then fluidity is improved for ink discharge, but atmosphere contamination occurs due to organic solvent evaporation

Engineering Contradiction:
ImprovefluidityVSAvoidatmosphere contamination
Core Design Contradiction:
Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The patent changes the chemical composition parameters by replacing organic solvents with water as the carrier liquid, and using inorganic pigments instead of organic colorants. This substitution maintains the necessary fluidity for inkjet discharge while eliminating harmful volatile organic compound evaporation, thus resolving the contradiction between operational ease and environmental harm.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent converts the typically harmful organic solvents into beneficial water-based components. By using water as the carrier and inorganic pigments that do not require organic solvents for dispersion, the system transforms a harmful substance into a benign one, achieving both good fluidity and zero atmosphere contamination.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

2Ease of operation

If solvent ink is used, then ink discharge fluidity is improved, but image quality deteriorates due to blurring on permeable surfaces

Engineering Contradiction:
Improveink discharge fluidityVSAvoidimage quality
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The patent changes the physical and chemical parameters of the ink formulation by using water-based carrier liquid with controlled viscosity and inorganic pigments with specific particle size distributions. These parameter changes enable the ink to maintain fluidity for proper discharge while forming sharp, non-blurring images on permeable surfaces through optimized evaporation and fixation characteristics.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If (meth)acrylates are used in photocurable ink, then optical curing speed is improved, but handling properties deteriorate due to odor and skin sensitization

Engineering Contradiction:
Improveoptical curing speedVSAvoidskin sensitization
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent converts the harmful (meth)acrylate monomers into beneficial inorganic pigment particles that can be optically cured. By using inorganic pigments such as metal oxides that undergo photocuring without the harmful properties of organic (meth)acrylates, the system achieves fast optical curing speed while eliminating odor and skin sensitization issues.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent changes the chemical composition from organic photopolymerizable monomers to inorganic photocurable pigment particles. This parameter change in the chemical nature of the curable component maintains rapid optical curing capability through photonic excitation while completely eliminating the toxicological hazards associated with (meth)acrylate handling.

Inventive Principle:
Principle #35Parameter changes

4Object-generated harmful factors

If liquid toner with non-volatile liquid is used, then atmosphere contamination is reduced, but image fixing becomes difficult due to bonding inhibition

Engineering Contradiction:
Improveatmosphere contaminationVSAvoidimage fixing
Core Design Contradiction:
Object-generated harmful factorsVSManufacturing precision

Solution Approach 1:

The patent converts the problematic non-volatile carrier liquid into a beneficial water-based system where the carrier evaporates cleanly without contamination. The inorganic pigments in this water-based liquid toner system achieve excellent bonding and image fixing through photocuring, transforming the previous bonding inhibition issue into effective image fixation.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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 silicone-based ink achieves high-definition images with improved handling properties, reduced odor and skin sensitivity, and increased image forming speed, while eliminating the need for heat fixation in electrophotography, thus enhancing the performance and energy efficiency of image forming apparatuses.

Implementation Method 1

The photosensitive ink contains polymerizable monomers or oligomers, photopolymerization initiators, and pigments and is capable of producing images quickly by curing the ink by polymerization reaction upon application of light such as ultraviolet.

Methodology Applied
Scientific EffectPhotopolymerization: Photopolymerisation

Implementation Method 2

as the liquid ink for use for inkjet, Japanese Patent Application Publication No. 2008-24881 (JP-2008-24881-A) describes curable compositions that contain ethylene-based unsaturated compounds such as (meth)acrylates and polystyrenes as ethylene-based unsaturated compounds having particular structures.

Methodology Applied
Scientific EffectAbsorption (EM radiation): Absorption (EM radiation)

Data Source

PatentEP2520579B1A silicone compound, photocurable liquid ink using the silicone compound, and method of manufacturing the ink
Publication Date: 2015.08.05 RICOH CO LTD
  • EP2520579B1 patent drawingFigure 1
  • EP2520579B1 patent drawingFigure 2
  • EP2520579B1 patent drawingFigure 3A~3B

AI summary

A silicone compound represented by the following Chemical Structure 1: where Y represents a substituted or non-substituted alkyl group having one to ten carbon atoms, X1, X2, and X3 independently represent methyl groups or any of the following Substituents A-1 to A-7, and 1, m, and n are independently zero or an integer of from 1 to 6, where R1 is a hydrogen atom, an alkyl group having one to four carbon atoms, or an alkoxy group having one to four carbon atoms, where R2 represents a single bonding or an alkylene group having one to four carbon atoms and R3 represents a single bonding or an alkyleneoxy group having one to four carbon atoms, where R4 and R5 independently represent hydrogen atoms or methyl groups,