Nozzle Ejection Control for Density Uniformity
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Solution Overview
Problem
Existing liquid ejecting apparatuses face challenges in maintaining uniformity of ink ejection across nozzles, leading to density unevenness in printed images, especially when dealing with varied original images that are not halftone, causing noticeable defects and inefficiencies in multi-apparatus printing.
Innovation Solution
A control method that adjusts the ejection amount of individual nozzles by setting drive modes based on pre-measured ejection amounts, generating drive signals for each pixel to compensate for variations, ensuring consistent output without relying on image processing, thereby maintaining uniform density across images.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If individual nozzle ejection amounts are not adjusted, then the printing process is simple and fast, but density unevenness occurs in the printed image
Solution Approach 1:
The patent applies local quality by adjusting the ejection amount control for each individual nozzle based on its specific characteristics. Each nozzle is assigned a unique control parameter derived from measuring its ejection amount, allowing localized compensation for nozzle-to-nozzle variations while maintaining overall system simplicity.
Solution Approach 2:
The system performs self-diagnosis and self-adjustment by automatically measuring the ejection amount of each nozzle during an initialization phase and storing the results in a lookup table. This self-characterization eliminates the need for manual calibration or complex external control systems, achieving density uniformity through the nozzle system's own performance data.
2Manufacturing precision
If image processing is applied to correct density variations, then density uniformity improves, but processing time increases and multi-apparatus consistency deteriorates
Solution Approach 1:
The patent performs the density correction action in advance during an initialization phase before actual printing occurs. By measuring and characterizing each nozzle's ejection amount during setup and storing this information in a lookup table, the system eliminates the need for time-consuming image processing during the printing operation itself.
Solution Approach 2:
The patent replaces the mechanical/software-based image processing approach with a hardware-level nozzle control solution. Instead of processing image data to compensate for density variations, the system directly controls the physical ejection amount of each nozzle based on pre-measured characteristics, achieving the same correction effect faster and more consistently.
3Manufacturing precision
If quantization process is executed for line drawings, then density uniformity improves, but dot defects occur and processing complexity increases
Solution Approach 1:
The patent extracts the density correction function from the image processing stage and relocates it to the nozzle control stage. By separating the correction mechanism from the quantization process, the system avoids the complexity of processing line drawings while maintaining density uniformity through direct nozzle ejection control.
Solution Approach 2:
The nozzle system performs self-characterization during initialization by measuring its actual ejection amount and storing this information in a lookup table. This self-service approach eliminates the need for complex image processing algorithms to handle different image types, as the correction is built into the nozzle control mechanism itself.
Data Source
AI summary
There is provided a liquid ejecting control method for outputting an image without an influence of ejection amount variations. Therefore among a plurality of drive modes in which an amount of liquids ejected from one nozzle is different from each other, control information indicating a drive mode to be associated is obtained, and a drive signal to an individual pixel is generated according to the control information and image data that is input for each pixel. The control information sets a drive mode in which an ejection amount closer to a target ejection amount is obtained, among the plurality of drive modes. In addition, a difference between the target ejection amount and the ejection amount to be realized in the set drive mode is found, and this difference is used to correct a target ejection amount of the other pixel in which the drive mode is not set yet.