Color Tone Correction Parameter Generation for Print Uniformity

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Solution Overview

Problem

Existing image forming apparatuses face challenges in achieving uniform color strength across prints due to temporal changes and nonuniformity in the sub-scanning direction, leading to defects like color strength skip, despite using color tone correction parameters generated from patches arranged in the sub-scanning direction.

Innovation Solution

An image processing apparatus that prints photoconductive image data based on color tone image data with patches arranged in a sequential order in the main scanning direction, allowing for the generation of a color tone correction parameter by comparing scanned and stored color tone data to correct color tone values and reduce nonuniformity in the sub-scanning direction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If patches are arranged in the sub-scanning direction for generating color tone correction parameters, then temporal changes can be corrected, but nonuniformity of color strength in the sub-scanning direction causes irrelevant color tone correction parameters and color strength skip

Engineering Contradiction:

Improvecorrection accuracyVSAvoidcolor strength uniformity

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent segments the color tone correction process by direction: it separates patches arranged in the main scanning direction (for correcting nonuniformity) from patches arranged in the sub-scanning direction (for correcting temporal changes). This segmentation allows independent optimization of correction parameters for each direction, preventing the mixing of irrelevant correction data that causes color strength skip.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by using different patch arrangements for different correction purposes: patches in the main scanning direction address local nonuniformity issues, while patches in the sub-scanning direction address temporal changes. This localized approach ensures that each correction parameter is generated from appropriate data, improving overall correction accuracy without introducing artifacts.

Inventive Principle:

Principle #3Local quality

2Device complexity

If patches of the same color and color tone are used for correction, then the correction process is simplified, but two patches are not enough to reduce nonuniformity of color strength effectively

Engineering Contradiction:

Improvecorrection process complexityVSAvoidcolor strength uniformity

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The patent adds a dimensional aspect to patch arrangement by organizing patches not only by color and tone but also by their spatial arrangement in the main scanning direction. This dimensional expansion allows multiple patches of the same color and tone to be distributed across different positions, providing sufficient data points to reduce nonuniformity while maintaining a relatively simple correction process.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Stability of the object's composition

If color tone correction parameters are generated to correct temporal changes, then color strength consistency over time is improved, but nonuniformity in the sub-scanning direction causes distorted color tone characteristics

Engineering Contradiction:

Improvecolor strength consistencyVSAvoidcolor tone accuracy

Core Design Contradiction:

Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The patent performs preliminary action by generating correction parameters specifically for the main scanning direction nonuniformity before addressing temporal changes. This preliminary correction of spatial nonuniformity prevents distorted color tone characteristics from being introduced when subsequent temporal change corrections are applied, ensuring both stability and accuracy.

Inventive Principle:

Principle #10Preliminary action

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 effectively reduces color strength nonuniformity and corrects temporal changes without causing color strength skip, improving print quality by arranging patches in the main scanning direction for each color, thereby enhancing the accuracy of color tone correction.

Implementation Method 1

a scanning portion to optically scan the patch row printed on the sheet

Methodology Applied

Scientific EffectOptical scanning: Reflection

Data Source

PatentUS8610950B2Image processing apparatus, image processing method, and computer- readable recording medium storing image processing program for generating color tone correction parameter

Publication Date: 2013.12.17 RICOH CO LTD

AI summary

An image processing apparatus is disclosed that includes a printing procedure request portion configured to request printing of color tone image data in a state where a patch row is arranged in a direction almost parallel with a main scanning direction; an image data obtaining portion configured to obtain scanned color tone data, showing scanned value of the patch row, from a scanning portion configured to optically scan the patch row; and a parameter generating portion configured to generate a color tone correction parameter for correcting color tone value of photoconductive image data by comparing the scanned color tone data and the color tone image data.