Image Forming Apparatus Calibration Using Photoconductor Patches
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Solution Overview
Problem
Existing image forming apparatuses face challenges in accurately calibrating image quality due to variations in patch image densities on the image carrier, which can lead to unstable image formation and quality over time, especially with changes in development process characteristics.
Innovation Solution
An image forming apparatus with a controller and calculator that forms multiple patch images with different densities, measures their densities, calculates a set value for a control amount based on these measurements, and calibrates this value to achieve a target density, ensuring stable image quality by using the calibrated set value during normal operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single patch image is used for calibration, then the calibration process is simple, but image quality becomes unstable due to variations in patch image densities
Solution Approach 1:
The calibration process is segmented into multiple stages: initial calibration using a first patch image to establish baseline parameters, and subsequent calibration using a second patch image to refine parameters. This segmentation allows the system to maintain stability while adapting to variations in development process characteristics over time.
Solution Approach 2:
The system performs preliminary calibration using the first patch image before normal image formation begins. This preliminary action establishes initial control amounts that account for variations in patch image densities, enabling stable image quality from the start of normal operation.
2Manufacturing precision
If control amounts are not calibrated, then the image forming operation is fast, but image quality varies due to changes in development process characteristics
Solution Approach 1:
The system implements feedback mechanisms where the density measurement device continuously monitors patch image densities, and the calculator adjusts control amounts based on measured values compared to target densities. This feedback loop ensures image quality consistency while minimizing calibration time through iterative optimization.
Solution Approach 2:
The system dynamically changes control parameters (such as development bias voltage or toner supply rate) based on measured patch image densities. By adjusting these parameters iteratively, the system achieves precise image formation quality while minimizing the time required for calibration through efficient parameter optimization.
3Measurement precision
If multiple patch images with different densities are formed, then calibration accuracy improves, but the number of operations increases
Solution Approach 1:
The system forms multiple patch images with different densities (excessive action) to ensure comprehensive calibration coverage, but uses selective measurement and intelligent calculation to avoid processing all possible variations. This approach achieves high measurement precision while maintaining calibration efficiency through focused optimization.
Data Source
AI summary
An image forming apparatus includes an image forming device, a controller, a density measurement device, and a calculator. The calculator detects a relationship (approximation line L1) between a control amount CV related to an image forming operation and a density D of an image formed on a photoconductor drum, which is an image carrier, and calculates a set value CV_TD of the control amount CV corresponding to a target density TD on the basis of the relationship. The controller forms a patch image on the photoconductor drum by using the set value CV_TD. The calculator calibrates the relationship on the basis of a difference ΔD between a density D10 of the patch image and the target density TD, and corrects the set value CV_TD on the basis of the calibrated relationship.