Image Processing Apparatus for Digital Printing Color Stability

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Solution Overview

Problem

Digital printing devices face challenges in maintaining stable color reproduction due to varying operating environments and device states, requiring frequent calibration and precise color management, especially when printing similar documents with small content changes or across different sites.

Innovation Solution

An image processing apparatus and method that corrects gradation characteristics and predicts output colors using a gradation correction parameter, incorporating a colorimeter to measure and correct colorimetric errors, thereby stabilizing color reproduction by minimizing differences between predicted and measured color values.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If digital printing devices operate continuously in varying environments, then productivity is maintained, but color reproduction stability deteriorates

Engineering Contradiction:

Improvecontinuous printing capabilityVSAvoidcolor reproduction stability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent implements a feedback mechanism where colorimetric measurements are continuously taken during printing operations, and the results are fed back to adjust the gradation correction parameters in real-time, maintaining color stability without stopping production

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system dynamically adjusts gradation correction parameters based on measured colorimetric values and predicted output colors, modifying the printing process parameters to compensate for environmental variations and maintain consistent color reproduction

Inventive Principle:

Principle #35Parameter changes

2Reliability

If calibration is performed periodically to maintain color stability, then color reproduction reliability is improved, but productivity decreases due to machine stops

Engineering Contradiction:

Improvecolor reproduction stabilityVSAvoidprinting continuity

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent enables continuous color correction during printing operations by using predicted color values and real-time measurements to adjust gradation parameters on-the-fly, eliminating the need to stop the machine for calibration while maintaining color stability

Inventive Principle:

Principle #20Continuity of useful action

Solution Approach 2:

The system performs self-correction by automatically measuring colorimetric values, comparing them with predicted outputs, and adjusting parameters without external intervention or manual calibration procedures, allowing the printing process to continue uninterrupted

Inventive Principle:

Principle #25Self-service

3Manufacturing precision

If color profiles are adjusted for each device state and media type, then color reproduction precision is improved, but device complexity increases

Engineering Contradiction:

Improvecolor reproduction precisionVSAvoidcolor management complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

Instead of maintaining multiple complex color profiles for different device states and media types, the patent uses a single color profile with dynamically adjusted gradation correction parameters that adapt to changing conditions, simplifying the overall color management system while maintaining precision

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The system transitions from static color profiles to dynamic parameter adjustments where gradation correction values are continuously optimized based on real-time measurements and predicted outputs, allowing one profile to serve multiple conditions effectively

Inventive Principle:

Principle #15Dynamics

4Measurement precision

If colorimetric measurements are taken to correct gradation characteristics, then color reproduction accuracy is improved, but measurement time increases

Engineering Contradiction:

Improvecolorimetric measurement accuracyVSAvoidmeasurement time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent calculates predicted color values before printing occurs, allowing the system to prepare correction parameters in advance and perform rapid real-time adjustments during printing without requiring extensive pre-measurement time

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system performs colorimetric measurements continuously during printing operations rather than requiring separate pre-printing calibration sessions, integrating measurement and correction into the ongoing printing process to minimize total time loss

Inventive Principle:

Principle #20Continuity of useful action

Data Source

PatentUS9742962B2Image processing apparatus, method, and recording medium storing image processing program for gradation correction to minimize the difference between the corrected colorimetric value and a colorimetric measured color value

Publication Date: 2017.08.22 RICOH CO LTD

AI summary

An image processing apparatus, an image processing method, and an image processing program stored in a recording medium are provided. The image processing apparatus includes a processing circuitry, and the processing circuitry and the image processing method obtain a color image output from an image forming unit, predict an output color of the image forming unit to generate a predicted color specification value independent from the image forming unit, extract from the input image data a colorimetry area for color difference determination, obtain a colorimetric value of an area of the color image that corresponds to the extracted colorimetry area, using a colorimeter, and add a colorimetric error at the colorimeter due to a color arrangement on the input image data to the predicted color specification value, to obtain a corrected colorimetric value of the area of the color image.