Image Density Control via Halftone Processing and Fixing Adjustment

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Solution Overview

Problem

Image forming apparatuses face challenges in maintaining high image quality due to variations in toner density and environmental conditions, leading to defects such as increased image density and narrowed color gamut, which affect productivity and color reproduction.

Innovation Solution

The apparatus includes a density-corrected image forming unit, a measurement unit, and an image correction unit that performs halftone processing on high-density solid image portions to adjust toner density and fixing conditions, such as increased fixing temperature, to match target image density and expand color gamut.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If halftone processing is performed on high-density solid image portions to match target image density, then image density control is improved, but color gamut is narrowed

Engineering Contradiction:

Improveimage density controlVSAvoidcolor gamut

Core Design Contradiction:

Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The patent applies halftone processing selectively only to high-density solid image portions (areas with image density exceeding a predetermined threshold) while leaving other areas unchanged. This localized approach allows density control where needed without affecting the overall color gamut of the image

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the halftone processing parameters (threshold value, processing intensity) based on the specific characteristics of the image density distribution. By adjusting these parameters dynamically, the system achieves accurate density control while minimizing impact on color gamut

Inventive Principle:

Principle #35Parameter changes

2Reliability

If fixing temperature is increased to improve toner fixation, then fixation reliability is improved, but energy consumption increases

Engineering Contradiction:

Improvetoner fixationVSAvoidfixing energy

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent dynamically adjusts the fixing temperature based on real-time detection of toner density and image characteristics. Rather than using a fixed high temperature, the system optimizes the fixing temperature for each specific imaging condition, achieving reliable fixation with minimal energy consumption

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent incorporates a feedback mechanism where the actual toner density and fixation quality are measured, and this information is used to adjust subsequent fixing parameters. This closed-loop control ensures reliable fixation while avoiding excessive energy use by only applying necessary heating

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 ensures that the image density matches the target while preventing color gamut narrowing, enhancing image quality and productivity by adjusting toner distribution and fixing energy.

Implementation Method 1

fixes a toner image on a recording medium with at least one of an increased fixing temperature

Methodology Applied

Scientific EffectHeating: Heating

Implementation Method 2

fixes a toner image on a recording medium with at least one of an increased fixing temperature

Methodology Applied

Scientific EffectMelting: Melting

Implementation Method 3

The measurement unit measures the density of the density corrected image

Methodology Applied

Scientific EffectAbsorption (EM radiation): Absorption (EM radiation)

Data Source

PatentUS9031433B2Image forming apparatus, non-transitory computer readable medium, and image forming method

Publication Date: 2015.05.12 FUJIFILM BUSINESS INNOVATION CORP

AI summary

An image forming apparatus includes an image forming unit, a density-corrected image forming unit, a measurement unit, an image correction unit, and a fixing unit. The image forming unit forms an image represented by image data as a toner image. The density-corrected image forming unit forms a density corrected image. The measurement unit measures the density of the density corrected image. The image correction unit performs image correction such that a non-halftone image is formed as a halftone image whose halftone percentage is less than 100%. The fixing unit, in a case where the image correction unit performs image correction for image data, fixes a toner image on a recording medium with at least one of an increased fixing temperature, an increased fixing time period, and an increased fixing pressure, the toner image being based on the image data for which image correction has been performed.