Print Method Adjusting Luminance Histograms for Surface Unevenness
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional printing methods fail to effectively create clear unevenness on a surface of a print medium, especially when there is a bias in the histogram of luminance values of grayscale image data, leading to inconsistent ink layer stacking and a lack of surface unevenness feeling.
Innovation Solution
A print method that adjusts the division position of luminance values in the histogram to set specific ranges for ink layer stacking, ensuring consistent and clear unevenness regardless of histogram bias, by dividing the luminance values into N ranges and adjusting the number of ink layers printed based on these ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional printing methods are used to print on a print medium, then the printing process is simple, but the surface unevenness feeling is not clear and inconsistent
Solution Approach 1:
The printing process is segmented into multiple independent ink layer applications (first ink layer, second ink layer, third ink layer, etc.). Each layer is printed separately with controlled coverage areas, allowing precise control over the final surface unevenness pattern. This segmentation enables clear surface unevenness feeling while maintaining a systematic but not overly complex process.
Solution Approach 2:
The invention transitions from conventional 2D printing to 2.5D printing by adding the height dimension through multiple stacked ink layers of different thicknesses. The first ink layer has different thickness in different regions, and subsequent layers are stacked thereon, creating actual surface unevenness that provides a tactile unevenness feeling while the printing process remains manageable.
2Manufacturing precision
If the number of ink layers is increased to create thicker uneven portions, then the surface unevenness feeling is enhanced, but the printing time and process complexity increase
Solution Approach 1:
Different regions of the print medium receive different numbers of ink layers based on the desired unevenness pattern. Some areas receive only one layer while others receive multiple stacked layers. This local variation in layer count creates well-defined uneven portions with clear unevenness feeling without requiring every area to undergo the same time-consuming multi-layer process.
Solution Approach 2:
Instead of applying multiple ink layers uniformly across the entire print medium, the invention applies additional layers only to specific regions where unevenness is desired. This partial action approach creates the necessary unevenness definition in target areas while avoiding the time penalty of processing the entire surface with the same complexity.
3Loss of information
If grayscale image data with histogram bias is used, then the image data reflects the original picture information, but the ink layer stacking becomes inconsistent and surface unevenness is not clear
Solution Approach 1:
Before printing the actual ink layers, the invention performs preliminary processing of the grayscale image data to generate a thickness map. This preliminary action identifies regions with histogram bias and adjusts the planned ink layer distribution in advance, ensuring that subsequent multi-layer printing will produce consistent unevenness patterns while preserving the original picture information.
Solution Approach 2:
The invention uses the histogram analysis of grayscale image data as feedback to adjust the ink layer stacking strategy. By analyzing the luminance value distribution and identifying biased regions, the system can compensate for potential inconsistencies in the printing process, ensuring uniform unevenness appearance while maintaining the integrity of the original image information.
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
The method achieves clear surface unevenness and expresses the unevenness feeling effectively, regardless of histogram bias, by varying the number of ink layers in the thickly-piled portions, resulting in a more realistic and textured print surface.
Implementation Method 1
an inkjet head that ejects an ultraviolet-curable ink, and an ultraviolet light source that irradiates the ink ejected on a print medium with ultraviolet light
Data Source
AI summary
In this print method, assuming that the number of stacking of ink layers in a thickest portion in a thickly-piled portion is N, in a histogram preparation step ST2, a histogram of luminance values of grayscale image data prepared in an image data preparation step ST1 is prepared, and in luminance value range setting steps ST3 to ST10, a luminance value of predetermined gradations of the histogram is divided into N and N luminance value ranges are set. In the luminance value range setting steps ST3 to ST10, a division position of the luminance value of the predetermined gradations is adjusted while the histogram displayed on a predetermined display is checked.