Inkjet Head with Functional Liquid for Graininess Reduction

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Solution Overview

Problem

Ink jet printing apparatuses face challenges in reducing graininess in highlight areas when printing on diverse media types, as existing image processing methods do not effectively address the issue of ink penetration and distribution across different surfaces.

Innovation Solution

A printing apparatus that includes a head capable of discharging colored ink and a functional liquid to promote penetration, using a normal mode for the front face and a bleed-through mode to print on both sides, with the functional liquid enhancing ink penetration and reducing graininess in highlight areas by adjusting discharge conditions based on lightness levels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If quantization processing is used for dot ON/OFF determination, then manufacturing precision is improved, but graininess worsens in highlight areas

Engineering Contradiction:
Improvedot formation precisionVSAvoidgraininess in highlight areas
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent applies different processing methods to different regions of the image. For highlight areas (light regions), it uses randomization processing to reduce graininess, while for non-highlight areas, it uses conventional quantization processing. This regional differentiation resolves the contradiction by optimizing each region according to its specific requirements.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes the processing parameter from fixed quantization thresholds to dynamic randomization based on position and lightness. By introducing randomness in the dot placement within highlight areas, it maintains the overall lightness while reducing the visible graininess caused by fixed quantization patterns.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If halftone processing is executed, then manufacturing precision is improved, but adaptability worsens for diverse media types

Engineering Contradiction:
Improvehalftone processing precisionVSAvoidadaptability to diverse media
Core Design Contradiction:
Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The patent makes the processing method dynamic by detecting the lightness of each pixel and applying different processing (quantization vs. randomization) based on the detected lightness value. This dynamic adaptation allows the system to maintain precision while being versatile across different media types and image regions.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent performs preliminary lightness detection and classification before applying the final dot formation processing. By pre-identifying highlight areas through lightness detection, it can apply the appropriate processing method (randomization for highlights, quantization for other areas) to resolve the contradiction between precision and adaptability.

Inventive Principle:
Principle #10Preliminary action

3Manufacturing precision

If colored ink discharge amount is reduced in light regions, then manufacturing precision is improved, but graininess worsens

Engineering Contradiction:
Improvelightness control precisionVSAvoidgraininess in light regions
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent introduces an intermediary randomization process between the lightness control and the final dot formation. Instead of directly controlling dot presence based on lightness, it uses randomization to distribute dots in a way that achieves the desired lightness while reducing graininess. This intermediary step resolves the contradiction by decoupling lightness control from graininess.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 apparatus effectively ameliorates graininess in highlight areas by using the functional liquid to soak and wet the surface of the medium, improving print quality across various media types while maintaining the desired lightness and color brightness.

Implementation Method 1

a functional liquid that promotes penetration of the colored ink

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Implementation Method 2

the functional liquid is discharged in addition to the colored ink, and so the colored ink soaks into and wets out the surface of the medium

Methodology Applied
Scientific EffectWetting: Wetting

Data Source

PatentEP3357699B1Printing apparatus and printing method
Publication Date: 2021.05.26 SEIKO EPSON CORP
  • EP3357699B1 patent drawingFigure 1
  • EP3357699B1 patent drawingFigure 2
  • EP3357699B1 patent drawingFigure 3

AI summary

A printing apparatus includes a head capable of discharging liquids toward a medium. The liquids include a colored ink and a functional liquid that promotes penetration of the colored ink. The printing apparatus has a normal mode to print a front face of the medium with the colored ink, and a bleed-through mode to print the front and reverse of the medium by printing the front face of the medium with the colored ink and using the functional liquid to cause the discharged colored ink to penetrate toward the reverse face of the medium. When printing in the normal mode, the colored ink and the functional liquid are used for forming regions having a specific lightness or greater.