Non-Uniform Print Mask for Inkjet Printhead Banding Reduction
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Solution Overview
Problem
Conventional swath-based inkjet printing systems face challenges in achieving high-quality images while maintaining high throughput, as they often require multiple printhead passes, leading to inter-swath banding and reduced printer speed.
Innovation Solution
The implementation of a non-uniform print mask design that varies the print density across printhead passes, allowing for reduced media advancement between swaths, thereby optimizing print quality and speed by distributing ink drops more efficiently across the media.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If uniform print masks are used to distribute ink drops evenly across printhead passes, then print quality is improved, but the number of printhead passes increases, reducing printer throughput
Solution Approach 1:
The patent applies local quality by varying the print density across different regions of the printhead array. Specifically, the print mask assigns different densities to different nozzle groups, with edge nozzles having lower density than center nozzles. This local differentiation allows the system to achieve acceptable print quality while reducing the total number of passes required, thereby improving throughput.
Solution Approach 2:
The patent changes the parameter of print density from uniform to non-uniform across the printhead array. By adjusting the density parameter differently for various nozzle regions and passes, the system optimizes the balance between print quality and number of passes. This parameter variation enables fewer passes while maintaining acceptable image quality.
2Productivity
If fewer printhead passes are used to increase printer throughput, then productivity is improved, but inter-swath banding increases and print quality deteriorates
Solution Approach 1:
The patent addresses inter-swath banding by applying local quality adjustments to different nozzle regions. Edge nozzles, which are more prone to causing banding artifacts, are assigned lower print densities compared to center nozzles. This local differentiation reduces the visibility of inter-swath banding while allowing fewer passes to be used, thereby maintaining high throughput.
3Manufacturing precision
If high print density is used across all nozzles to achieve photo quality images, then manufacturing precision is improved, but the number of printhead passes increases significantly, reducing speed
Solution Approach 1:
The patent applies local quality by differentiating print density requirements for different nozzle positions. Center nozzles, which contribute most to image quality, maintain higher print densities, while edge nozzles use lower densities. This approach achieves photo quality in the critical center regions while reducing the overall pass requirement, thereby improving printing speed.
Solution Approach 2:
The patent applies partial action by concentrating the full print density effort on center nozzles that are most critical for image quality, while using reduced density for edge nozzles. This partial application of high density where most needed achieves photo quality without requiring the excessive number of passes that would be needed if uniform high density were applied across all nozzles.
Data Source
AI summary
According to one example, a printer includes an inkjet printhead, and the printhead comprises nozzles through which printing fluid is ejectable during a pass of the printhead across a print zone. Processing printhead control data includes obtaining printhead control data describing pixel locations in an image to be printed on a media, and allocating, for a swath of the image, each of the pixel locations to a printhead nozzle and to a print pass of a set of print passes in accordance with a print mask. The print mask defines sections associated different groups of the nozzles.