Auto Color Registration via Spatial Period Test Patterns
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Solution Overview
Problem
Conventional image forming apparatuses execute auto color registration (ACR) without considering mechanical change factors due to photoconductors and drive rollers, leading to inaccuracies in color registration.
Innovation Solution
The method involves printing test patterns on an intermediate transfer belt by adjusting the printing time interval according to the spatial periods of both photoconductors and drive rollers, using a sensor unit to measure distances and calculate compensation values for precise ACR in both paper feeding and main scanning directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If ACR is executed without considering mechanical change factors of photoconductors and drive rollers, then the ACR process is simple and fast, but the color registration precision deteriorates
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing spatial periods of photoconductors and drive rollers, and pre-determining test pattern printing intervals based on these spatial periods. This preparation is done before ACR execution, allowing the system to account for mechanical change factors without adding computational complexity during the actual ACR process. The test patterns are printed at predetermined intervals that already incorporate the mechanical characteristics of the components.
Solution Approach 2:
The patent replaces direct mechanical measurement and complex mechanical modeling with an optical sensing approach. Instead of mechanically measuring the actual positions and accounting for mechanical variations, the system uses optical test patterns and sensor detection to indirectly measure registration deviations. This substitution of mechanical measurement with optical detection simplifies the system while improving precision.
2Measurement precision
If test patterns are printed at fixed intervals without considering spatial periods, then the printing process is simple, but the measurement precision of mechanical changes deteriorates
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the test pattern printing interval based on the spatial periods of photoconductors and drive rollers. Instead of using a fixed interval, the system calculates and uses a variable interval that adapts to the specific mechanical characteristics of each component. This parameter adjustment enables precise measurement of mechanical changes while keeping the printing control straightforward.
3Manufacturing precision
If only one mechanical factor (photoconductor or drive roller) is considered, then the analysis is simple, but the registration accuracy deteriorates due to unaccounted mechanical changes
Solution Approach 1:
The patent applies segmentation by separately analyzing and measuring the spatial periods of photoconductors and drive rollers independently. Each component's mechanical characteristics are measured and stored separately, allowing the system to account for both factors without creating a complex coupled analysis. The test patterns are designed to detect deviations caused by each component independently, and the results are combined to achieve overall registration accuracy.
Data Source
AI summary
An image forming apparatus and a control method thereof which execute auto color registration in consideration of mechanical change factors of both photoconductors and drive rollers. The control method of an image forming apparatus includes photoconductors, an intermediate transfer belt to which developers attached to the photoconductors are transferred, and drive rollers to drive the intermediate transfer belt, test patterns are printed on the intermediate transfer belt by adjusting a printing time interval of the test patterns according to a spatial period of the photoconductors and a spatial period of the drive rollers, if conditions to execute auto color registration (ACR) are satisfied, and ACR is executed according to a signal reflected by the test patterns.