Inkjet Density Measurement Conversion for Unevenness Correction
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Solution Overview
Problem
Inkjet recording systems face challenges in accurately detecting density unevenness due to variations in ink ejection and drying conditions, leading to reduced measurement accuracy and noise influence.
Innovation Solution
An image processing method and program that uses a density measurement value conversion process to convert pre-dry density values into post-dry values, accounting for variations in ink ejection and drying conditions, allowing for accurate unevenness correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If density measurement is performed immediately after printing before drying, then measurement speed is improved, but measurement accuracy deteriorates due to light scattering changes and reduced noise sensitivity
Solution Approach 1:
The patent performs preliminary actions by measuring density values at multiple stages (immediately after printing, after drying, and after fixation) to capture the complete density change trajectory. This allows the system to predict final density values based on initial measurements while accounting for drying effects, thereby maintaining both speed and accuracy.
Solution Approach 2:
The patent implements feedback mechanisms by continuously monitoring density changes at different stages and using this information to adjust correction values. The system compares density measurements before and after drying to calculate conversion factors that compensate for light scattering changes, ensuring accurate density representation throughout the process.
2Loss of time
If ink is not sufficiently dried or fixed, then processing time is reduced, but light scattering characteristics change making density detection difficult
Solution Approach 1:
The patent introduces intermediary conversion factors that mediate between density measurements taken at different stages. These conversion factors translate initial density values (taken when ink is wet) into equivalent final density values (after drying and fixation), allowing the system to detect density accurately without waiting for complete drying while compensating for light scattering changes.
Solution Approach 2:
The patent applies parameter changes by dynamically adjusting measurement and correction parameters based on the drying state of the ink. The system modifies density conversion factors and measurement thresholds according to whether the ink is in a wet or dried state, enabling consistent detection accuracy across different processing stages without requiring complete drying.
3Device complexity
If correction processing is performed without accounting for drying variations, then processing simplicity is maintained, but manufacturing precision deteriorates due to ink amount detection errors
Solution Approach 1:
The patent segments the correction processing into distinct modules: initial density measurement, drying effect analysis, conversion factor calculation, and corrected density value generation. This segmentation allows the system to handle drying variations systematically through separate processing steps rather than attempting to account for all factors simultaneously, maintaining manageable complexity while improving precision.
Solution Approach 2:
The patent replaces complex mechanical adjustment mechanisms with computational correction methods. Instead of physically adjusting for drying effects through multiple printing passes or manual intervention, the system uses algorithms and conversion factors to computationally correct density measurements, achieving high precision with minimal processing complexity.
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 method enables effective unevenness correction by reducing noise influence and improving measurement accuracy, ensuring consistent ink density across regions.
Implementation Method 1
light scattering on an ink surface relatively becomes large. Thus, even if the same image is read out, the quantity of light entered into the image sensor becomes smaller as a whole in a state where ink is undried or unfixed than a state after the drying or fixing of the ink progresses
Data Source
AI summary
An image processing method includes: forming an image for density unevenness measurement on a recording medium in a single-pass method, using an inkjet head in which nozzles are disposed in a main scanning direction; acquiring a density measurement value of each set gradation value from an image for density unevenness measurement before drying; converting the acquired density measurement value into a conversion density measurement value corresponding to a post-dry density measurement value, using a density measurement value conversion value set for each region in the main scanning direction; and deriving a new unevenness correction value using this conversion density measurement value.