Image Density Calibration for Scan-Direction Unevenness
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Solution Overview
Problem
Existing image forming apparatuses face challenges in accurately correcting density unevenness in the scanning direction due to variations in environmental conditions and component characteristics, leading to reduced correction accuracy.
Innovation Solution
The image forming apparatus employs a controller to form detection images, generate first and second image forming conditions to adjust density unevenness, and control the image forming unit to create test images based on these conditions, using exposure correction amounts determined from density data to correct density unevenness accurately.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single detection image is used for density unevenness correction, then the correction process is simple, but the correction accuracy decreases under varying environmental conditions
Solution Approach 1:
The patent divides the correction process into multiple stages: first forming a detection image under initial conditions to obtain basic correction data, then forming additional detection images under different environmental conditions (temperature, humidity) to obtain condition-specific correction data. This segmentation allows the system to select appropriate correction data based on current environmental conditions, improving accuracy without requiring all corrections to be applied simultaneously.
Solution Approach 2:
The patent implements dynamic selection of correction data based on detected environmental conditions. The system continuously monitors temperature and humidity, then dynamically selects from multiple sets of correction data stored in memory, choosing the set that best matches current conditions. This dynamic adaptation enables high correction accuracy across varying environments without requiring a permanently complex correction system.
2Measurement precision
If multiple detection images are formed under different environmental conditions, then the correction accuracy improves, but the time and resources required increase
Solution Approach 1:
The patent performs preliminary calibration by forming detection images under multiple predetermined environmental conditions in advance and storing the resulting correction data in memory. This preliminary action creates a library of correction data that can be quickly retrieved and applied during actual operation, eliminating the need to perform time-consuming multiple detections whenever environmental conditions change.
Solution Approach 2:
The patent creates multiple copies of correction data corresponding to different environmental conditions and stores them in memory. Instead of repeatedly forming detection images under different conditions, the system makes copies of correction data for various conditions and selects the appropriate copy based on current environmental sensors, dramatically reducing calibration time while maintaining accuracy.
3Adaptability or versatility
If the detection image density is set far from the target density, then the density unevenness correction range is larger, but the correction accuracy at the target density decreases
Solution Approach 1:
The patent applies different detection image density settings for different correction scenarios. For obtaining baseline correction data, detection images are formed at densities away from the target density to capture a wide range of unevenness. For obtaining condition-specific correction data under varying environmental conditions, detection images are formed at densities closer to the target density to ensure high accuracy. This local quality approach optimizes both range and accuracy for different purposes.
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 allows for precise correction of density unevenness in the scanning direction, even with changes in environmental conditions and component states, ensuring high accuracy and consistency in image quality.
Implementation Method 1
a light source configured to expose the photosensitive member to light to form an electrostatic latent image
Data Source
AI summary
An image forming apparatus includes an image forming unit including a photosensitive member, a light source, and a developing roller, and a controller configured to control the image forming unit to form a detection image, obtain density data regarding density levels in a plurality of areas in the detection image at a plurality of positions in a scanning direction in which the photosensitive member is scanned with the light from the light source, generate, based on the density data, a first image forming condition for forming a first test image and a second image forming condition for forming a second test image, the second image forming condition being different from the first image forming condition, and control the image forming unit to form the first test image and the second test image, respectively based on the first image forming condition and the second image forming condition.