Inkjet Head Nozzle Segmentation for Background Image Ink Mixing
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Solution Overview
Problem
Ink jet printing devices face image quality deterioration due to mixing of background and image inks before the background ink has dried, leading to premature mixing and blending of inks.
Innovation Solution
A printing device with separate nozzle lines for background and image inks, where the inks are ejected in a specific pattern to create a nozzle unused area between their respective areas, allowing for controlled relative movement to prevent premature mixing, using a controller to manage the ejection and transportation of the medium in both scanning directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If background ink and image ink are ejected in sequence without interruption, then printing efficiency is improved, but ink mixing occurs and image quality deteriorates
Solution Approach 1:
The patent divides the nozzle arrangement into distinct segments: a first nozzle line for background ink and a second nozzle line for image ink, with a deliberate gap (nozzle unused area) between them. This segmentation prevents ink mixing by spatially separating the ejection zones while maintaining continuous printing capability through coordinated operation of both nozzle lines.
Solution Approach 2:
The patent introduces a third dimension in the nozzle arrangement by creating a gap in the sub-scanning direction between the first and second nozzle lines. This dimensional separation allows both background and image inks to be ejected simultaneously or in rapid sequence without mixing, resolving the contradiction between printing efficiency and image quality.
2Speed
If nozzles are arranged continuously to maximize coverage, then printing speed is improved, but ink from different nozzles mixes and contaminates each other
Solution Approach 1:
The patent extracts or removes a portion of the nozzle arrangement in the sub-scanning direction, creating a nozzle unused area between the first and second nozzle lines. This intentional omission prevents ink contamination by ensuring that ink ejected from one nozzle line does not contact or mix with ink from the other nozzle line, while printing speed is maintained through coordinated ejection from both lines.
3Manufacturing precision
If background ink is allowed to dry completely before applying image ink, then image quality is improved, but printing time increases significantly
Solution Approach 1:
The patent applies preliminary action by ejecting background ink from the first nozzle line and simultaneously or nearly simultaneously ejecting image ink from the second nozzle line, with the spatial separation ensuring no mixing occurs. This eliminates the need to wait for background ink to dry completely before applying image ink, significantly reducing printing time while maintaining image quality.
Solution Approach 2:
The patent maintains continuity of useful action by enabling simultaneous or rapid sequential ejection from both nozzle lines without interruption or waiting periods. The nozzle unused area ensures that this continuous operation does not result in ink mixing, allowing the printing process to proceed without time loss while preserving image quality.
Data Source
AI summary
A printing device that forms a background by a first ink and images on the background by a second ink includes a head having first and second nozzle lines that eject, respectively, the first and second inks. The inks are ejected as the head moves, with respect to a medium, in a main scanning direction intersecting the first and second nozzle lines. A transport section transports the medium in a sub-scanning direction along the first and second nozzle lines. In an ejecting operation, the first and second inks are ejected in the relative movement in the main scanning direction and the relative transportation in the sub-scanning direction is performed. In the sub-scanning direction, first and second nozzle line used areas are set where the first and second inks, respectively, are ejected from the first and second nozzle lines. A nozzle unused area is defined therebetween.