Printing Apparatus Nozzle Control for Gloss Unevenness
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Solution Overview
Problem
Serial printing apparatuses using pigment ink face issues with gloss unevenness due to the limited amount of resin composition in ink, leading to reduced gloss and density when high-density printing is performed, especially noticeable in bidirectional printing modes.
Innovation Solution
A printing apparatus with a print head having nozzles for both dark and light ink of the same color type, where the usage rates of nozzles are controlled to discharge a larger amount of light ink in succeeding passes to maintain resin composition on the printing medium, reducing gloss unevenness and allowing for efficient halftone processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the amount of resin composition in dark ink is increased to achieve high-gloss output, then gloss level is improved, but the ink formulation becomes difficult to create and the density of output color ink is reduced due to diffused reflection of light
Solution Approach 1:
The patent divides the ink discharge process into multiple passes with different nozzle configurations. In the first pass, nozzles discharge dark ink containing pigment composition. In subsequent passes, different nozzles discharge light ink containing resin composition. This segmentation allows each ink type to be optimized independently while achieving both high gloss and high density output.
Solution Approach 2:
The patent combines dark ink (with pigment composition) and light ink (with resin composition) in a single printing process by using multiple nozzles that discharge both ink types in sequence. The light ink discharged in subsequent passes remains on the printing medium surface to provide gloss, while the dark ink provides density. This merging resolves the contradiction by achieving both components' benefits simultaneously.
2Manufacturing precision
If multiple scans are executed to form an image with high density, then printing quality is improved, but printing speed is reduced due to time intervals between scans
Solution Approach 1:
The patent performs preliminary ink discharge in the first pass using nozzles for dark ink, establishing the base density. Then in subsequent passes, nozzles for light ink discharge additional material to enhance gloss. This preliminary action allows the printing process to maintain high quality through multiple scans while optimizing the timing and distribution of ink discharge to minimize total printing time.
3Productivity
If the number of scans or time interval between scans is reduced for faster printing, then printing speed is improved, but gloss unevenness occurs due to insufficient resin composition remaining on the printing medium
Solution Approach 1:
The patent assigns different functions to different nozzles based on their discharge timing. Nozzles in the first pass discharge dark ink for density, while nozzles in subsequent passes discharge light ink for gloss. By controlling which nozzles discharge in which passes, the system ensures sufficient resin composition remains on the printing medium to prevent gloss unevenness, even when scanning multiple times at high speed.
Data Source
AI summary
A printing apparatus has a plurality of nozzles capable of discharging dark ink and light ink that are of the same type color; the plurality of nozzles includes preceding nozzles that discharge the ink onto the printing medium before the ink discharge of the other nozzles, and succeeding nozzles that discharge the ink onto the printing medium after the ink discharge of the preceding nozzles, and if the amount of the dark ink discharged on the printing target region is larger than a predetermined amount, the printing apparatus discharges a smaller amount of the light ink than the amount of the discharged dark ink onto the printing target region from the plurality of nozzles so that the amount of the light ink discharged from the succeeding nozzles is larger than the amount of the light ink discharged from the preceding nozzles.