Variable-Distance Inkjet Print Head for Droplet Ratio Control
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Solution Overview
Problem
Existing inkjet printers face issues with streaks and color unevenness due to varying nozzle array distances, which cause ink droplets to interfere and bleed, especially when the printing duty increases.
Innovation Solution
The printer employs a print head with multiple nozzle arrays having different nozzle array distances and controls the ejection of ink droplets of varying sizes to form dots of different sizes, adjusting the ratio of small and large droplets based on the nozzle array distance to minimize interference and bleeding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If multiple head chips are arranged in the width direction and overlapping in the transport direction to cover the entire width, then the printing coverage is improved, but streaks and color unevenness occur due to varying nozzle array distances
Solution Approach 1:
The print head is divided into multiple head chips (first head chip and second head chip) with different nozzle array distances. The first head chip has a first nozzle array distance and the second head chip has a second nozzle array distance, allowing each segment to handle different printing duties independently
Solution Approach 2:
Different regions of the print head are assigned different nozzle array distances based on local printing requirements. The first head chip region uses a first nozzle array distance optimized for certain conditions, while the second head chip region uses a second nozzle array distance optimized for other conditions, achieving local optimization of printing quality
2Productivity
If the nozzle array distance is shortened to increase printing speed, then productivity is improved, but ink droplets interfere and bleed causing color unevenness
Solution Approach 1:
The nozzle array distance parameter is changed across different head chips. The first head chip has a first nozzle array distance and the second head chip has a second nozzle array distance, allowing the system to adapt the nozzle array distance parameter based on printing duty requirements to prevent ink droplet interference while maintaining productivity
3Manufacturing precision
If the nozzle array distance is increased to prevent ink droplet interference, then color uniformity is improved, but printing duty capacity decreases
Solution Approach 1:
The printing system is segmented into multiple head chips that can handle different printing duties. By dividing the print head into multiple functional units with different nozzle array distances, the system can process high-duty printing tasks without requiring a single oversized nozzle array distance that would reduce overall productivity
Data Source
AI summary
The print head 10 includes a nozzle region NA1 in which a distance between a nozzle array 23Y and a nozzle array 23C is a distance D1 and a nozzle region NA2 in which a distance between a nozzle array 23Y and a nozzle array 23C is a distance D2. When a ratio of sizes of a plurality of ink droplets ejected from nozzles of a nozzle region NA1 is defined as a first ratio and a ratio of sizes of a plurality of ink droplets ejected from nozzles of a nozzle region NA2 is defined as a second ratio, a control section 30 executes a first print in which a ratio of ink droplets having a size other than a maximum size in the second ratio is smaller than a ratio of ink droplets having a size other than a maximum size in the first ratio.