Inkjet Printing Defect Reduction via Density Thresholds
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Solution Overview
Problem
Inkjet printing defects such as dry-time banding and swath contraction occur due to high colorant densities and are not effectively addressed by existing technologies, leading to suboptimal print quality.
Innovation Solution
The method involves determining colorant densities for each colorant, calculating dry-time signal strength and swath contraction strength, and adjusting the printing process by setting thresholds to prevent defects, including altering printing directions and incorporating non-printing passes to mitigate dry-time banding and swath contraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high colorant densities are used to achieve high print quality, then printing density and image quality are improved, but dry-time banding and swath contraction defects occur
Solution Approach 1:
The printing process is divided into multiple passes with different printing directions (first direction and second direction opposite to the first). Different colorants are selectively printed in different passes based on their drying characteristics. This segmentation allows high colorant densities to be used while preventing dry-time banding by ensuring proper drying between passes.
Solution Approach 2:
Different printing strategies are applied to different colorants based on their specific properties. For example, colorants with longer drying times are printed in specific passes while those that dry faster are handled differently. This local differentiation of printing quality and timing prevents swath contraction and dry-time banding while maintaining overall print quality.
2Manufacturing precision
If multiple printing passes are used to reduce defects, then printing quality is improved, but printing speed is reduced
Solution Approach 1:
The printing process dynamically adjusts the number and sequence of passes based on the specific colorants being printed and their drying characteristics. The system adapts the printing strategy in real-time, using single-pass printing when possible and multi-pass printing only when necessary to prevent defects, thereby optimizing printing speed while maintaining quality.
Solution Approach 2:
The system changes printing parameters such as pass direction, pass timing, and colorant selection based on detected conditions. By adjusting these parameters dynamically, the system achieves high print quality without unnecessarily slowing down the printing process through excessive passes.
3Productivity
If bidirectional scanning is used to improve printing efficiency, then printing speed is improved, but uneven densities occur at the ends of scanning ranges
Solution Approach 1:
The scanning range is divided into multiple zones with different printing strategies. The system identifies areas prone to uneven densities at the ends of scanning ranges and applies specialized printing techniques to those zones while maintaining standard bidirectional scanning in the middle sections, thus preserving overall printing speed while correcting density issues.
Solution Approach 2:
Different printing quality control measures are applied to different regions of the print media. The ends of scanning ranges receive enhanced monitoring and adjustment to prevent uneven densities, while the center regions continue with optimized bidirectional scanning, maintaining overall efficiency without sacrificing local quality.
Data Source
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AI summary
A method for reducing printing defects in inkjet printing includes determining a respective colorant density for each colorant of a plurality of colorants for a region to be printed; determining a colorant dry-time signal strength as a function of a combined colorant density value based on the respective colorant densities of the plurality of colorants for the region to be printed; determining a respective colorant swath contraction strength for each colorant as a function of the respective colorant density; selecting a dry-time threshold which if met by the colorant dry-time signal strength indicates that a dry-time defect may occur; selecting a respective colorant density threshold for each colorant which if met by the respective colorant density indicates a visible swath contraction may occur; and determining a printing action to be taken based on whether the dry-time threshold is met and whether at least one respective colorant density threshold is met.