UV LED Printer Ink Dryer Units for Balanced Drying

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Solution Overview

Problem

Conventional drying methods for print operations, such as infrared drying, result in inefficient energy use and potential substrate damage due to uneven evaporation rates of different ink colors, leading to overheating and increased energy consumption.

Innovation Solution

Employing ultraviolet light sources, specifically ultraviolet light emitting diodes (UV LEDs) that emit light in a narrow band within the UV range (200-400nm), which preferentially absorbs by colorants rather than solvents, facilitating efficient solvent evaporation through heat transfer from the colorants, thereby balancing drying times and reducing substrate heating.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If infrared drying is used, then drying of ink is achieved, but energy consumption increases and substrate damage occurs due to uneven evaporation rates

Engineering Contradiction:
Improvedrying efficiencyVSAvoidenergy consumption
Core Design Contradiction:
ProductivityVSLoss of energy

Solution Approach 1:

The patent applies selective wavelength irradiation targeted at specific colorants in different ink regions. Each colorant absorbs radiation at its characteristic wavelength, creating localized heating that promotes uniform evaporation across different ink colors without overall energy waste. This resolves the contradiction by making the drying process spatially and spectrally selective rather than uniform and broad-spectrum.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention changes the radiation parameter from broad-spectrum infrared to specific ultraviolet wavelengths (200-400nm) that match colorant absorption characteristics. This parameter change enables efficient energy utilization by matching the radiation wavelength to the absorption spectrum of each colorant, thereby reducing energy consumption while maintaining high drying productivity.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If infrared drying is used, then drying of ink is achieved, but substrate overheating and damage occur due to uneven evaporation rates

Engineering Contradiction:
Improvedrying speedVSAvoidsubstrate damage
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent uses wavelength-selective irradiation that targets specific colorants rather than heating the entire substrate uniformly. Each colorant absorbs radiation at its specific wavelength range, creating localized thermal effects that promote evaporation without causing overall substrate overheating. This resolves the contradiction by concentrating energy where needed while protecting the substrate from harmful thermal effects.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention converts the previously harmful effect of uneven evaporation into a beneficial selective heating mechanism. By exploiting the different absorption characteristics of various colorants, the system creates controlled local heating that accelerates drying while preventing the substrate damage that would result from uniform infrared heating. The selective absorption that once caused unevenness is now used to control and balance the drying process.

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

3Adaptability or versatility

If broad-spectrum radiation is used for drying, then all ink colors can be dried, but energy absorption is uneven leading to inefficient drying

Engineering Contradiction:
Improvemulti-color ink drying capabilityVSAvoidenergy absorption efficiency
Core Design Contradiction:
Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The patent employs wavelength-selective irradiation tailored to each colorant's absorption spectrum. Instead of using broad-spectrum radiation that treats all colors equally, the system applies specific wavelengths that each colorant absorbs efficiently. This resolves the contradiction by making the energy absorption process color-specific, thereby improving overall energy efficiency while maintaining the ability to dry multiple ink colors.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention changes the radiation parameter from fixed broad-spectrum to variable wavelength-selective irradiation. By adjusting the radiation wavelength to match each colorant's absorption maximum, the system achieves efficient energy utilization across all ink colors. This parameter adaptation resolves the contradiction between versatile multi-color drying capability and energy absorption efficiency.

Inventive Principle:
Principle #35Parameter changes

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 ensures consistent evaporation rates across different ink colors, reduces energy consumption, and minimizes substrate damage by maintaining balanced energy absorption and efficient drying processes, while also reflecting non-absorbed UV light to prevent substrate warping.

Implementation Method 1

The light source emits light in a relatively narrow band (for example, having a bandwidth of around 20-30nm) in the UV range... The energy absorption efficiencies of the colorants for the emitted light are within a range of 30%

Methodology Applied
Scientific EffectAbsorption of UV radiation by colorants: Absorption (EM radiation)

Implementation Method 2

the heating of the solvent fluid (for example, water) is substantially due to heat transfer from the colorant

Methodology Applied
Scientific EffectHeat transfer from colorant to solvent: Conduction (thermal)

Implementation Method 3

causing evaporation of the solvent fluid from the printer ink

Methodology Applied
Scientific EffectEvaporation of solvent: Evaporation

Data Source

PatentEP3124261B1Printer ink dryer units
Publication Date: 2023.06.07 HP SCITEX LTD
  • EP3124261B1 patent drawingFigure 1~2
  • EP3124261B1 patent drawingFigure 3~4
  • EP3124261B1 patent drawingFigure 5~6

AI summary

In an example, a printer ink dryer unit comprises at least one ultraviolet light source to dry a printer ink layer by causing evaporation of a solvent fluid therefrom.