Overprint Processing in Image Forming Apparatus

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Solution Overview

Problem

Existing image forming apparatuses face issues with overprint processing, as they may alter original color values due to device-specific characteristics, leading to undesired output results when converting between different color spaces, particularly when performing overprint operations on regions where the foreground object overlaps the background.

Innovation Solution

The apparatus includes a determination unit to identify subtractive color mixing, a first color conversion unit to convert non-subtractive color spaces to subtractive, an overprint detection unit to specify overprint processing, and a second color conversion unit to adjust image data based on device characteristics after overprint processing, ensuring accurate color preservation and desired output.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If color conversion is performed before overprint processing to correct device characteristics, then output color accuracy is improved, but original color values are altered leading to undesired overprint results

Engineering Contradiction:
Improveoutput color accuracyVSAvoidoriginal color values
Core Design Contradiction:
Manufacturing precisionVSLoss of information

Solution Approach 1:

The patent applies preliminary action by performing overprint processing before color conversion. The flow controller executes overprint processing on the original color values first, then performs color conversion on the result. This ensures that overprint operations use the authentic original color values while still achieving accurate output colors through subsequent device-specific color conversion.

Inventive Principle:
Principle #10Preliminary action

2Adaptability or versatility

If overprint processing is performed on converted color values, then device output characteristics are optimized, but color fidelity to original input is degraded

Engineering Contradiction:
Improvedevice output characteristicsVSAvoidcolor fidelity
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent reverses the conventional sequence by performing overprint processing before color conversion rather than after. This preliminary action ensures that overprint operations are executed on the original, unconverted color values, preserving color fidelity while still allowing device-specific color conversion to be applied to the final output.

Inventive Principle:
Principle #10Preliminary action

3Adaptability or versatility

If color conversion is performed early in the processing pipeline, then device compatibility is improved, but overprint processing accuracy deteriorates

Engineering Contradiction:
Improvedevice compatibilityVSAvoidoverprint processing accuracy
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent performs overprint processing as a preliminary action before color conversion. The flow controller executes overprint operations on the original color values first, ensuring high overprint processing accuracy, then applies color conversion for device compatibility in subsequent steps.

Inventive Principle:
Principle #10Preliminary action

4Adaptability or versatility

If overprint processing is performed after color conversion, then device characteristics are accommodated, but original color information is lost

Engineering Contradiction:
Improvedevice characteristics accommodationVSAvoidoriginal color information
Core Design Contradiction:
Adaptability or versatilityVSLoss of information

Solution Approach 1:

The patent inverts the conventional processing sequence by performing overprint processing before color conversion instead of after. This inversion preserves original color information during overprint operations while still achieving device characteristics accommodation through the subsequent color conversion step.

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

Data Source

PatentEP2741258B1Image forming apparatus performing overprint processing
Publication Date: 2020.02.12 KYOCERA DOCUMENT SOLUTIONS INC
  • EP2741258B1 patent drawingFigure 1
  • EP2741258B1 patent drawingFigure 2
  • EP2741258B1 patent drawingFigure 3

AI summary

A first color conversion unit converts image data having a color space based on mixing other than subtractive color mixing into image data having a color space based on subtractive color mixing. A drawing processing unit (13) performs overprint processing for the image data having the color space based on subtractive color mixing such that, if a color value of a foreground object for which overprinting has been specified indicates that a region where the foreground object overlaps a background object is colored, a color value of the overlapping region is overwritten with the color value of the foreground object, and otherwise, the overlapping region is not overwritten with the foreground object. A second color conversion unit converts image data subsequent to the overprint processing into image data having output colors in accordance with characteristics of the image forming apparatus.