Fluorescent Patch Calibration Using Overlapped Non-Fluorescent Dots
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Solution Overview
Problem
Existing color calibration methods for fluorescent inks are inaccurate due to the influence of unevenness in fluorescent whitening agents, leading to incorrect determination of ink discharge amounts and reduced calibration accuracy.
Innovation Solution
A control apparatus that controls printing of patches using both fluorescent and non-fluorescent materials, with at least one dot of the non-fluorescent material overlapping a dot of the fluorescent material, and corrects the printing amount based on reflected light measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a light source emitting UV light is used to measure fluorescent ink density, then the measurement can capture fluorescent characteristics, but the unevenness of fluorescent whitening agent causes measurement value changes that cannot be distinguished from actual ink discharge changes
Solution Approach 1:
The patent divides the measurement process into two separate measurements: one using UV light to excite fluorescence and another using visible light for reflection measurement. By segmenting the measurement into these two distinct components, the system can separately analyze fluorescent characteristics and reflection characteristics, then combine them to compensate for the unevenness caused by fluorescent whitening agents.
Solution Approach 2:
The patent introduces a correction value calculated from visible light reflection measurement as an intermediary to mediate between the raw fluorescent measurement and the final corrected measurement. This intermediary correction value compensates for the unevenness introduced by fluorescent whitening agents, allowing accurate determination of actual ink discharge amounts.
2Device complexity
If only fluorescent material is used for printing, then the calibration process is simpler, but the unevenness of fluorescent whitening agent cannot be distinguished from ink discharge changes
Solution Approach 1:
The patent employs a composite measurement approach that combines fluorescent ink measurement with non-fluorescent ink measurement. By printing patches with both fluorescent and non-fluorescent materials and measuring their respective characteristics, the system creates a composite measurement model that can distinguish between fluorescent whitening agent unevenness and actual ink discharge variations.
Solution Approach 2:
The patent implements a feedback mechanism where the measurement results from both fluorescent and non-fluorescent patches are used to calculate correction values. These correction values are then fed back into the calibration process to adjust and improve the accuracy of ink discharge amount determination, continuously compensating for fluorescent whitening agent unevenness.
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
Accurately performs color calibration by minimizing the impact of fluorescent whitening agent unevenness, enhancing the accuracy of color calibration for printing apparatuses using fluorescent materials.
Implementation Method 1
a measurement device, reading a printed patch with a measurement device... obtained by receiving light separated by using a white light source having wavelengths in ultraviolet (UV) and visible light ranges and a diffraction grating
Implementation Method 2
calibration utilizing a patch of a fluorescent ink printed on a sheet containing a fluorescent whitening agent... a change in the measured value of the measurement device originates from a change in the discharge amount of the ink
Data Source
AI summary
A control apparatus that functions as a control unit controlling printing of a fluorescent material patch on a printing medium, an estimation unit to estimate a discharge amount of the fluorescent material based on a reflection intensity obtained by receiving light reflected by the patch on the printing medium, and a correction unit to correct a printing amount of the fluorescent material based on an estimation result. The patch is printed using the fluorescent material and a non-fluorescent material, and at least one dot of the non-fluorescent material overlaps a dot of the fluorescent material. A luminous wavelength of a fluorescent whitening agent contained in the printing medium is an excitation wavelength of the fluorescent material, and the non-fluorescent material absorbs at least one of light in an excitation wavelength range of the fluorescent whitening agent or light in a luminous wavelength range of the fluorescent whitening agent.