Image-Forming Device Calibration Using Partial Density Patches
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Solution Overview
Problem
The existing calibration processes for image-forming devices are inefficient as they require measuring numerous density levels, which slows down the process and consumes excessive consumables, such as toner, due to the need for forming and measuring density patches for all density levels.
Innovation Solution
An image-forming device with a sensor, storing unit, reference ratio determining unit, estimated ratio determining unit, and density correcting unit that forms density patches only at reference densities, determines reference ratios, and uses these ratios to correct image data for other densities, reducing the number of patches needed for calibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If density patches are formed for all density levels to ensure comprehensive calibration coverage, then calibration precision is improved, but the number of patches increases leading to slower process speed and higher consumable usage
Solution Approach 1:
The patent applies partial action by forming density patches only at selected reference densities (e.g., 5 density levels out of 256 possible levels) rather than all density levels. The measured data from these reference patches is then used to calculate calibration coefficients that are applied to correct image data across the entire density range, achieving comprehensive calibration coverage with minimal physical patches.
2Measurement precision
If density patches are formed for all density levels to ensure comprehensive calibration coverage, then calibration precision is improved, but consumable usage increases
Solution Approach 1:
The patent reduces toner consumption by forming density patches only at 5 reference density levels instead of all 256 density levels. This partial sampling approach provides sufficient calibration data to derive correction coefficients for the entire density range, significantly reducing developer/toner usage while maintaining calibration accuracy.
3Measurement precision
If numerous density patches are formed and measured to acquire calibration data for all density levels, then calibration completeness is improved, but the calibration process time increases
Solution Approach 1:
The patent measures only 5 reference density patches instead of 256 patches, reducing the physical measurement process time. The system then uses interpolation and calculation to determine calibration coefficients for all intermediate density levels, achieving complete calibration coverage with minimal measurement time.
Solution Approach 2:
The patent performs preliminary measurement and calibration at selected reference density levels before applying the derived calibration coefficients to correct image data across the entire density range. This preliminary action at key reference points enables rapid correction of all other density levels without requiring individual measurement of each level.
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 calibration while minimizing the number of density patches, thereby reducing resource consumption and speeding up the calibration process.
Implementation Method 1
The sensor detects the densities of the density patches formed by the image-forming unit and outputs a measured output value for each reference density
Data Source
AI summary
An image-forming device includes: an image-forming unit; a sensor; a storing unit; a reference ratio determining unit; an estimated ratio determining unit; and a density correcting unit. The image-forming unit is capable of forming a plurality of density patches corresponding to a plurality of reference densities. The sensor detects the densities of the density patches and outputs a measured output value for each reference density. The storing unit stores reference output values for the reference densities. The reference ratio determining unit determines reference ratios to compensate for differences between the measured output values and the reference output values for the reference densities. The estimated ratio determining unit determines estimated ratios corresponding to densities other than the reference densities based on the reference ratios for the reference densities. The density correcting unit corrects density of image data based on the reference ratios and estimated ratios.