Inkjet Printing Glossiness via Light Ink First Pass
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Solution Overview
Problem
Inkjet printing on glossy paper surfaces results in impaired glossiness due to the slow absorption of pigment inks, leading to uneven ink layers and surface roughness, as pigment molecules do not easily dissolve in water and are dispersed as particulates, which are larger than the surface holes, causing them to be deposited on the surface rather than penetrating, and subsequent ink droplets coagulate in uncolored areas, deteriorating image granularity and glossiness.
Innovation Solution
The inkjet printing apparatus and method optimize ink droplet placement by arranging nozzle arrays to eject inks with the highest lightness first, ensuring a weighted average printing rate that maximizes the contact and leveling of ink droplets on the surface, reducing variance and preventing excessive contact that causes surface roughness, thereby improving glossiness and image quality without complicating the printing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multipass printing is performed on glossy paper, then ink fixation is improved, but glossiness is impaired
Solution Approach 1:
The patent applies preliminary action by performing a first printing pass with light ink to create a base layer, then subsequent passes with dark ink. This staged approach allows the light ink to set properly before adding darker layers, preventing the glossiness impairment that occurs when multiple dark ink layers are applied sequentially without proper spacing.
Solution Approach 2:
The patent uses local quality by differentiating ink application based on position and density. Light ink is applied to areas requiring softer tones and better gloss preservation, while dark ink is applied to areas requiring strong saturation. This localized differentiation allows each ink type to be optimized for its specific function, maintaining glossiness where needed while ensuring fixation where required.
2Quantity of substance
If pigment ink is applied to glossy paper, then color saturation is improved, but surface smoothness is impaired
Solution Approach 1:
The patent segments the ink application process into multiple passes with different ink types. Instead of applying all pigment ink at once, it separates light ink application from dark ink application across different passes. This segmentation allows the surface to remain smoother during light ink application, then builds color saturation gradually in subsequent passes, preventing the surface roughness that would result from applying all pigment ink simultaneously.
3Productivity
If ink droplets are applied in multiple passes, then image completeness is improved, but surface unevenness increases
Solution Approach 1:
The patent employs periodic action by implementing a specific sequence of light and dark ink passes. The pattern alternates between light ink application passes and dark ink application passes, creating a rhythmic deposition process. This periodic structure ensures that lighter, smoother ink layers are deposited before heavier, more saturated layers, allowing the surface to level between passes and preventing cumulative unevenness that would occur with random multi-pass application.
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 enhances the glossiness and smoothness of the printed surface by ensuring that ink droplets with the highest lightness form the top layer, reducing surface unevenness and maintaining image quality, while suppressing the deterioration of granularity caused by excessive ink contact, resulting in high-quality images.
Implementation Method 1
ink droplets contact each other before fixation completes on the printing medium surface, leveling will arise, the unevenness of the printing medium surface will decrease
Implementation Method 2
ink droplets applied by each printing scan dries one by one on the printing medium, and are fixed while they are piled on one another
Implementation Method 3
its pigment molecule is hard to dissolve in water and is dispersed in the moisture as particulates
Data Source
AI summary
The present invention provides an inkjet printing apparatus and an inkjet printing method for printing a high-definition image while improving glossiness of the image surface without causing complication and enlargement of the apparatus. A plurality of inks are ejected from first and second printing heads so that a weighted average of a printing rate for each scan regarding an ink having the highest lightness becomes the largest among the plurality of inks and so that a maximum value regarding the printing rate of the ink having the highest lightness becomes larger than those of other inks.