Common Voltage Color Imaging Density Calibration
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Solution Overview
Problem
Color imaging devices with a common voltage supply face challenges in managing color accuracy and toner usage, as they struggle to maintain optimal image density across multiple color cartridges sharing a single power source.
Innovation Solution
A method is introduced where an acceptable range of color density is determined for each toner, and a common operating point is selected based on the lowest deviation from the optimum density, allowing four color developer rolls to operate from a single power supply while ensuring acceptable color images are produced.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a common voltage supply is used for all color cartridges, then economic efficiency and device simplicity are improved, but color accuracy and image density control deteriorate
Solution Approach 1:
The patent applies parameter changes by determining acceptable density ranges for each color toner and selecting a common operating voltage that minimizes deviation from optimum density across all colors. This involves measuring density at different voltages, establishing acceptable ranges, and choosing an operating point that balances performance across all color cartridges sharing the common power supply.
2Manufacturing precision
If dedicated power supplies are used for each color cartridge, then color accuracy and toner usage are improved, but device complexity and cost increase
Solution Approach 1:
The patent merges the power supply functions for cyan, magenta, and yellow cartridges into a single common voltage supply, reducing device complexity while maintaining acceptable color accuracy through careful selection of the common operating voltage based on density measurements and deviation minimization across all color channels.
3Manufacturing precision
If the common operating point is set for one color, then that color's image density is optimized, but other colors may fall outside their acceptable density ranges
Solution Approach 1:
The patent segments the problem by determining acceptable density ranges for each color independently, then uses these segmented ranges to evaluate and select a common operating voltage that achieves the lowest cumulative deviation across all colors, balancing performance for each individual color channel.
Solution Approach 2:
The patent employs feedback by measuring the actual image density produced by each color cartridge at different voltage levels, comparing these measurements against acceptable density ranges, and using this feedback information to select the optimal common operating voltage that minimizes overall deviation from target densities.
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 the production of high-quality color images by selecting a common operating voltage that minimizes deviations across all toners, preventing overly dark images and optimizing toner usage, even when all cartridges share a single power supply.
Implementation Method 1
A corona or charge roller 32 sets a charge on a surface of the drums 30
Implementation Method 2
The laser beam 22 electrostatically discharges the drums to create a latent image
Implementation Method 3
A developer roller 34 introduces toner to the latent image and such is electrostatically attracted to create a toned image on a surface of the drums 30
Implementation Method 4
A voltage differential between the surface of the drums 30 and transfer rolls 36 transfers the toned image from the drums to a surface of an intermediate transfer member (ITM) 40
Data Source
AI summary
A color imaging device includes a plurality of developer rolls with a common operating point, such as a common operating voltage. To determine the operating point, an acceptable range of color density is determined for each toner, the range being lighter and darker than an optimum color density for that toner. A search range is devised such that values within the range are examined relative to deviations from the optimum color density per each toner. The common operating point is selected as that having the lowest deviation per all toners. Also, if the common operating point corresponds to a color density darker than the acceptable range of color density for any toner, additional halftoning occurs compared to traditional halftoning, such as for continuous tones or solids. In this way, four color developer rolls can be operated from a single power supply, yet still provide acceptable color images.