Inkjet Recording Head Ink Array Asymmetry

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Solution Overview

Problem

Conventional inkjet recording apparatuses experience color differences and image quality deterioration due to ink landing position deviations when scanning, particularly when using a recording head with a light blue ink discharge opening array unit between black ink units, which increases the distance between black ink discharge opening array units, leading to significant image quality issues when the head is tilted or scans are tilted.

Innovation Solution

The recording head is designed with a specific arrangement of discharge opening array units to reduce color differences between forward and backward scans and minimize image quality deteriorations by symmetrically arranging cyan, magenta, and yellow ink units between black ink units, and placing the light blue ink unit asymmetrically with respect to black ink units, while optimizing the discharge rates of each ink to avoid simultaneous large-scale discharge of light blue and black inks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the light blue ink discharge opening array unit is arranged between two black ink discharge opening array units to reduce color difference, then the color difference between forward and backward scans is reduced, but the distance between the two black ink discharge opening array units becomes relatively long, causing image quality deterioration due to ink landing position deviations

Engineering Contradiction:
Improvecolor consistencyVSAvoidink landing position precision
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent applies asymmetry by arranging the light blue ink discharge opening array unit asymmetrically with respect to the black ink discharge opening array units. Specifically, the light blue ink unit is positioned closer to one black ink unit than to the other, breaking the symmetric pattern. This asymmetric arrangement reduces the distance between black ink units while maintaining the benefit of reduced color difference between forward and backward scans, thereby solving the technical contradiction between color consistency and ink landing position precision.

Inventive Principle:
Principle #4Asymmetry

2Illumination intensity

If cyan and magenta inks having low lightness are applied in a superimposing manner to reproduce blue hue, then the blue hue can be reproduced, but image graininess becomes notable

Engineering Contradiction:
ImprovelightnessVSAvoidimage smoothness
Core Design Contradiction:
Illumination intensityVSManufacturing precision

Solution Approach 1:

The patent changes the lightness parameter of the ink by introducing a light blue ink with higher lightness than both cyan and magenta inks. This parameter change allows the reproduction of blue hue without the graininess problem, as the light blue ink provides sufficient brightness while maintaining color accuracy, thus resolving the contradiction between lightness and image smoothness.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If two light blue ink discharge opening array units are provided and two black ink discharge opening array units are arranged between them to decrease distance, then the distance between black ink units is decreased, but the number of discharge opening array units increases, leading to increased apparatus size and cost

Engineering Contradiction:
Improveink landing position precisionVSAvoidrecording head structure
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent uses asymmetric arrangement to optimize the position of the single light blue ink discharge opening array unit relative to the black ink units. This asymmetric positioning allows the system to achieve adequate ink landing position precision without needing to increase the number of discharge opening array units, thereby avoiding increased apparatus size and cost while still improving upon the symmetric arrangement's drawbacks.

Inventive Principle:
Principle #4Asymmetry

Data Source

PatentEP3287290B1Recording head and inkjet recording apparatus
Publication Date: 2019.07.17 CANON KK
  • EP3287290B1 patent drawingFigure 1
  • EP3287290B1 patent drawingFigure 2
  • EP3287290B1 patent drawingFigure 3

AI summary

A light blue ink discharge opening array unit is located between cyan ink discharge opening array units, between the magenta ink discharge opening array units, and not between the black ink discharge opening array unit.