Dynamic Nozzle Assignment for Liquid Ejecting Apparatus
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Solution Overview
Problem
Ink jet printers face challenges in minimizing the position control range of a medium during 5-color printing, leading to increased blank spaces at the upper and lower ends of the medium, which can result in transport errors and reduced image quality.
Innovation Solution
The printer configuration includes a first nozzle row for white ink and a second nozzle row for color ink, where the nozzles are strategically positioned and displaced to minimize the position control range by setting the first nozzles forming the first image on the upstream side relative to the second nozzles forming the second image at the middle portion and adjusting their positions at the upper and lower ends to ensure uniform transport distance and prevent irregular image concentration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If nozzles for printing background image are fixed to upstream side nozzles and nozzles for color image are fixed to downstream side nozzles, then chromogenic properties of image are improved, but position control range of medium becomes long
Solution Approach 1:
The patent applies dynamics by making the nozzle assignment dynamic rather than fixed. The control unit selectively assigns nozzles based on the printing region: for middle portion printing, upstream nozzles print background and downstream nozzles print color images; for upper end portion printing, downstream nozzles are assigned to print background images. This dynamic reassignment optimizes both image quality and position control range for different printing scenarios.
Solution Approach 2:
The patent applies local quality by implementing different nozzle assignment strategies for different regions of the medium. The middle portion uses one nozzle assignment pattern (upstream for background, downstream for color), while the upper end portion uses another pattern (downstream for background). This region-specific optimization ensures that each area gets the most appropriate nozzle configuration for its specific requirements.
2Ease of operation
If position control range of medium is long, then blank spaces at upper and lower ends of medium increase, but transport errors occur and image quality deteriorates
Solution Approach 1:
The patent uses dynamic nozzle assignment to reduce the effective position control range. By assigning downstream nozzles to print background images at the upper end portion, the printing operations can be completed within a shorter medium transport distance, thereby reducing blank spaces and minimizing transport errors while maintaining ease of operation.
3Manufacturing precision
If nozzles are arranged at narrow interval, then dot rows are formed at high resolution, but position control precision becomes more difficult
Solution Approach 1:
The patent addresses this contradiction through dynamic nozzle assignment combined with precise control of transport distance. By selectively assigning nozzles based on printing region and carefully controlling the medium transport distance between passes, the system maintains high dot row resolution while managing position control precision through active adaptation rather than fixed configuration.
Data Source
AI summary
A liquid ejecting apparatus includes: a first nozzle row in which first nozzles ejecting a first liquid are arranged in a predetermined direction; a second nozzle row in which second nozzles ejecting a second liquid are arranged in the predetermined direction; a movement mechanism moving the first and second nozzle rows in a movement direction intersecting the predetermined direction relative to a medium; a transport mechanism transporting the medium in the predetermined direction relative to the first and second nozzle rows; and a control unit repeating an image forming operation of ejecting the liquids from the first and second nozzles while moving the first and second nozzle rows in the movement direction by the movement mechanism and a transport operation of transporting the medium in the predetermined direction relative to the first and second nozzle rows by the transport mechanism. When a first image is formed with the first liquid in a given image forming operation and then a second image is formed with the second liquid on the first image in another image forming operation, the control unit sets the first nozzles forming the first image to the nozzles located on an upstream side in the predetermined direction relative to the second nozzles forming the second image in forming the first and second images at a middle portion of the medium, and sets the first nozzles forming the first image to the nozzles located on a downstream side in the predetermined direction relative to the first nozzles, which form the first image at the middle portion of the medium, in forming the first and second images at an upper end portion of the medium.