Printer Lightfastness via Yellow Ink Drop Control

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Solution Overview

Problem

Existing printing technologies face challenges in maintaining the lightfastness of printed images, as conventional methods to improve light resistance, such as altering ink chemistry and using protective overcoats, often compromise color strength and incur additional costs.

Innovation Solution

The solution involves controlling the drop volume and drop frequency of yellow ink droplets in printers, increasing the drop volume and reducing the drop frequency compared to cyan and magenta ink droplets, to enhance lightfastness by optimizing the distribution of ink on the media, thereby leveraging the shielding effect of the top pigment layer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional methods (altering ink chemistry, protective overcoats, lightfastness additives) are used to improve light resistance, then lightfastness is improved, but color strength is compromised and additional cost is incurred

Engineering Contradiction:

ImprovelightfastnessVSAvoidcolor strength

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The patent applies different drop volume settings to different color channels (yellow versus cyan/magenta). By making the yellow ink drops larger and more sparse, the patent creates a local quality difference that exploits the shielding effect of yellow pigment particles to protect underlying layers, thereby improving lightfastness without compromising overall color strength

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the physical parameters of ink deposition by increasing drop volume for yellow ink while reducing drop frequency. This parameter change transforms the distribution pattern from conventional uniform small drops to larger, sparser drops, achieving improved lightfastness through physical arrangement rather than chemical modification

Inventive Principle:

Principle #35Parameter changes

2Reliability

If conventional methods (altering ink chemistry, protective overcoats, lightfastness additives) are used to improve light resistance, then lightfastness is improved, but additional cost is incurred

Engineering Contradiction:

ImprovelightfastnessVSAvoidprinting cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent enables the printing system to control its own lightfastness properties through software-based drop volume and frequency adjustments. By using the printer's existing hardware capabilities with modified deposition parameters, the system achieves improved lightfastness without requiring additional protective coatings or specialized ink formulations, thereby avoiding additional manufacturing costs

Inventive Principle:

Principle #25Self-service

3Reliability

If drop volume of yellow ink is increased and drop frequency is reduced, then lightfastness is improved, but ink distribution uniformity may be affected

Engineering Contradiction:

ImprovelightfastnessVSAvoidink distribution uniformity

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent introduces asymmetry in the ink deposition pattern by making yellow ink drops larger and more sparsely distributed compared to cyan and magenta drops. This asymmetric distribution creates overlapping patterns where larger yellow drops provide shielding protection while maintaining acceptable visual uniformity through the combined effect of all color channels

Inventive Principle:

Principle #4Asymmetry

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 improves the lightfastness of printed images by reducing fade rates over time without compromising color appearance, as demonstrated by the retention of optical density after accelerated exposure, with significant improvements observed in the kinetics of fade for yellow inks with higher drop weights and reduced frequencies.

Implementation Method 1

leveraging the shielding effect of the top pigment layer

Methodology Applied

Scientific EffectShielding effect: Absorption (EM radiation)

Data Source

PatentUS8864267B2Lightfastness control for printers

Publication Date: 2014.10.21 HEWLETT PACKARD DEVELOPMENT COMPANY LP

AI summary

A printer includes an ink reservoir that includes yellow ink, cyan ink, and magenta ink. The printer includes an ink dispenser that employs a yellow distribution setting to increase the drop volume of yellow ink droplets and lower the drop frequency of the yellow ink droplets on the media with respect to the cyan ink droplets and/or magenta ink droplets to control the lightfastness of the print on the media.