Image Density Correction Using Specular and Diffuse Light Detection
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Solution Overview
Problem
Existing image forming apparatuses face challenges in accurately detecting image density due to the influence of stray light, which cannot be sufficiently eliminated using correction coefficients based on the ratio between specular and diffuse reflected light from patch marks of a single density type, leading to increased measurement errors from changes in the use environment or over time.
Innovation Solution
The apparatus generates chromatic color patch marks on a carrier element, detects specular and diffuse reflected light, and uses correction parameters to align the detected values from different patch marks, allowing for accurate density calculation and image forming conditions determination, thereby eliminating the impact of stray light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If correction coefficients are calculated using patch marks of one density type, then the measurement process is simple, but stray light influence cannot be eliminated and measurement precision deteriorates
Solution Approach 1:
The invention divides the correction process into multiple independent correction coefficients: a first correction coefficient for specular reflected light and a second correction coefficient for diffuse reflected light. Each coefficient is calculated separately using patch marks of different density types, allowing independent optimization of correction for each light component and enabling precise elimination of stray light influence.
2Measurement precision
If light quantity emitted by irradiation unit is increased to improve detection sensitivity, then detection capability improves, but stray light component increases and measurement precision deteriorates
Solution Approach 1:
The invention extracts and separately corrects the harmful stray light component by calculating dedicated correction coefficients for both specular and diffuse reflected light. This allows the system to maintain high light emission quantities for improved detection sensitivity while mathematically removing the stray light influence through independent correction processing.
3Device complexity
If patch marks of one density type are used for correction, then the correction process is simple, but correction precision is insufficient to eliminate stray light
Solution Approach 1:
The invention applies different correction approaches to different light components: a first correction coefficient is specifically calculated for specular reflected light using patch marks with high density, while a second correction coefficient is calculated for diffuse reflected light. This localized correction strategy ensures high precision for each component while keeping the overall process manageable through systematic organization.
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 enables precise detection of image density by correcting for stray light influences, ensuring accurate image formation and reducing errors caused by environmental or temporal changes.
Implementation Method 1
a first light receiving element for detecting the specular reflected light
Implementation Method 2
a second light receiving element for detecting the diffuse reflected light
Data Source
AI summary
An image forming apparatus is provided. The image forming apparatus includes, a carrier element, an image forming unit, a patch mark generation unit, a specular reflected light detection unit that detects light irradiated onto the carrier element by the irradiation unit and specularly-reflected by the carrier element or patch marks, and a diffuse reflected light detection unit that detects the light irradiated onto the carrier element by the irradiation unit and diffusely-reflected by the carrier element or the patch marks. Additionally, the image forming apparatus includes, a correction unit that corrects at least one of a value detected by the specular reflected light detection unit and the diffuse reflected light detection unit, a correction condition determination unit that determines correction conditions for the correction unit, and a density calculation unit that calculates a density of a patch mark.