One-Pass Inkjet Correction Using Reference Color Components

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Solution Overview

Problem

Conventional image recording apparatuses face challenges in correcting density unevenness, especially in one-pass type systems, which require numerous charts and increased environmental load, and suffer from accuracy reduction due to conversion errors from three-dimensional to four-dimensional color spaces.

Innovation Solution

An image recording apparatus with a head part that ejects ink droplets of different color components, a moving mechanism, and a correction part that synchronizes ink ejection with the movement of the recording medium, allowing for correction of color component values based on reference color components, reducing the need for extensive chart recording and improving accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If correction values are obtained for various mixed colors using conventional methods, then the accuracy of correction is improved, but the number of charts needed increases enormously and environmental load increases

Engineering Contradiction:
Improvecorrection accuracyVSAvoidnumber of charts
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The invention segments the correction process into two distinct stages: (1) obtaining correction values for single color components using a small number of charts, and (2) synthesizing correction values for mixed colors through computational processing. This segmentation eliminates the need to create charts for all possible color combinations, dramatically reducing the number of charts required while maintaining correction accuracy.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention performs preliminary correction value acquisition for individual color components before actual image recording. By obtaining correction values for single color components in advance and storing them, the system prepares all necessary correction data beforehand, eliminating the need to acquire mixed color correction values during operation and reducing the number of charts needed.

Inventive Principle:
Principle #10Preliminary action

2Ease of operation

If RGB values are converted into CMYK values after correction values are obtained on an RGB space, then the correction process is simplified, but the accuracy is reduced due to conversion errors from three-dimensional space to four-dimensional space

Engineering Contradiction:
Improvecorrection process simplicityVSAvoidcolor accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The invention inverts the conventional approach by performing correction value acquisition and processing in the CMYK color space from the beginning, rather than working in RGB space and converting to CMYK later. This inversion eliminates conversion errors between color spaces while maintaining the simplicity of the correction process, as all operations are performed natively in the target CMYK space.

Inventive Principle:
Principle #13The other way round (Inversion)

3Productivity

If a one-pass type image recording apparatus is used to reduce recording time, then productivity is improved, but it becomes more difficult to correct density unevenness compared to multipass type apparatus

Engineering Contradiction:
Improverecording speedVSAvoiddensity uniformity
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The invention implements a feedback mechanism where correction values obtained from recording test charts are used to adjust and optimize the recording process. By measuring the actual density output and using this feedback to refine correction values, the system compensates for the limitations of one-pass recording, achieving both high productivity and uniform density through iterative optimization.

Inventive Principle:
Principle #23Feedback

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 solution enables efficient correction of color mixing unevenness with fewer charts and reduced environmental impact, while maintaining accuracy by determining correction values based on reference color components, thus simplifying the acquisition of required correction information.

Implementation Method 1

an image recording apparatus which records an image on a recording medium by ink jet method through relative movement of an ejection part which ejects fine droplets of ink from a plurality of ejection ports

Methodology Applied
Scientific EffectInk jet ejection:

Data Source

PatentEP3632690B1Image recording apparatus, image recording method, and correction information acquisition method
Publication Date: 2023.03.29 SCREEN HOLDINGS CO LTD
  • EP3632690B1 patent drawingFigure 1~2
  • EP3632690B1 patent drawingFigure 3
  • EP3632690B1 patent drawingFigure 4

AI summary

In an image recording apparatus, when an image is recorded on a recording medium, the recording medium passes through a head part only once (Step S26). Before the image is recorded, a value of a color component of at least some of pixels included in the image is corrected in order to reduce color mixing unevenness. At that time, on the basis of respective values of two reference color components among a plurality of color components of a correction target pixel, a value of one target color component included among the two reference color components is corrected. Alternatively, on the basis of respective values of three reference color components among the plurality of color components, a value of one target color component or respective values of two target color components included among the three reference color components are corrected (Steps S22, S23).