Banding Compensation in Marking Platforms Using 1x Sensors
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Solution Overview
Problem
Current systems lack an efficient method to compensate for banding defects in marking platforms due to multiple and variable sources, such as photoreceptors, developer rollers, and drive rollers, which cause periodic density variations in printed images.
Innovation Solution
The implementation of low-cost once around (1x) sensors on multiple banding sources to provide fundamental frequency characteristics, combined with a calibration stage using multipage coherent FFT and cubic spline interpolation, to determine phase and amplitude characteristics, and derive exposure correction signals for effective banding compensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple banding sources (PR, developer roller, BCR, BTR, drive rollers) are present in the marking platform, then the marking platform can perform complex marking functions, but banding compensation becomes difficult due to multiple variable sources
Solution Approach 1:
The patent segments the banding compensation problem by individually analyzing and compensating for each banding source (PR, developer roller, BCR, BTR, drive rollers) separately. Each source is assigned its own compensation parameters and correction signals, allowing the complex multi-source banding problem to be broken down into manageable individual components that can be addressed through separate measurement and correction processes.
Solution Approach 2:
The patent implements dynamic banding compensation by continuously monitoring and adjusting compensation parameters in real-time during operation. The system adapts to changing banding characteristics of each source as they vary over time, using ongoing measurements and updated correction signals to maintain accurate compensation despite the variable nature of multiple banding sources.
2Device complexity
If traditional single-source banding compensation methods are used, then the compensation process is simple, but it cannot effectively handle multiple variable banding sources
Solution Approach 1:
The patent divides the banding compensation system into separate modules for each banding source, with individual measurement and correction processes. This segmentation allows the system to maintain the simplicity of single-source compensation methods for each individual source while achieving reliable multi-source compensation through the combined effect of all individual corrections.
Solution Approach 2:
The patent merges the compensation results from multiple individual banding source corrections into a unified correction process. By combining the separate compensation signals and parameters for all banding sources (PR, developer roller, BCR, BTR, drive rollers), the system achieves reliable overall banding compensation while maintaining the simplicity of individual source handling.
3Productivity
If banding sources are not compensated, then the marking process is fast and simple, but periodic density variations degrade image quality
Solution Approach 1:
The patent applies preliminary banding compensation by measuring and pre-calculating correction signals before the actual marking process. The system performs banding characterization and compensation parameter determination in advance, storing correction data that can be rapidly applied during high-speed marking operations, thus maintaining both speed and image quality uniformity.
Solution Approach 2:
The patent implements feedback-based banding compensation by continuously monitoring banding characteristics during operation and adjusting correction signals in real-time. This feedback mechanism allows the system to maintain image quality uniformity despite variations in marking conditions, while the rapid feedback processing minimizes impact on marking speed.
Data Source
AI summary
A method for compensation of banding in a marking platform includes: initiating a calibration stage; marking a test pattern over multiple intervals of a lowest fundamental frequency among marking modules; obtaining image data for the test pattern from a sensor; obtaining 1x signals from sensors associated with the marking modules; and processing the image data in relation to the 1x signals to form banding profiles for multiple marking modules. Alternatively, the method may include: processing image data in relation to 1x signals to form banding profiles for multiple marking modules; determining amplitudes in multiple banding profiles exceeds a threshold to identify dominant banding profiles; and processing dominant banding profiles to form dominant banding signatures. Alternatively, the method may include: initiating a correction stage; obtaining 1x signals from sensors associated with dominant marking modules; and periodically processing dominant banding signatures and 1x signals to determine a banding compensation value.