Inkjet Printer Color Density Correction Across Print Width
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Solution Overview
Problem
Inkjet printers face challenges in achieving consistent color density across the printing width due to variations in ink flow velocity, temperature, or pressure, leading to inconsistent droplet formation and print quality.
Innovation Solution
A method involving printing a 2-dimensional pattern with varying nominal densities, recording color values, deriving correction curves, and adjusting printing signals to compensate for deviations, using a single camera and control unit to correct nozzle performance inline.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If manual adjustment methods are used to correct nozzle deviations, then individual nozzle performance can be optimized, but the process becomes time-consuming, labor-intensive, and error-prone
Solution Approach 1:
The system performs self-calibration by automatically printing test patterns, capturing images with a camera, analyzing the printed patterns to detect nozzle deviations, and generating correction curves without human intervention. The control unit executes the entire calibration process autonomously, allowing the inkjet printer to correct its own printing inconsistencies
Solution Approach 2:
The system implements a closed-loop feedback mechanism where the printed pattern is captured by a camera, analyzed to determine actual print density and nozzle performance, and this information is fed back to the control unit which then adjusts the printing signals. This continuous feedback loop enables automatic correction of printing deviations
2Manufacturing precision
If printing signals are corrected for each nozzle individually, then drop formation consistency can be improved, but the system complexity and computational requirements increase
Solution Approach 1:
The printing width is divided into multiple columns, with each column corresponding to a specific nozzle or group of nozzles. Correction curves are generated independently for each column, allowing individualized adjustment of printing signals for each nozzle group while maintaining overall system manageability
Solution Approach 2:
The system adjusts printing parameters such as voltage pulse amplitudes, durations, and shapes applied to piezo elements based on measured deviations. By dynamically changing these electrical parameters, the system compensates for nozzle variations and homogenizes drop formation across all nozzles
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Ensures high-quality, consistent color density across the printing width by homogenizing droplet formation, reducing manual intervention, and minimizing errors, while being cost-effective and time-efficient.
Implementation Method 1
Recording with a camera at least one color value for each nominal print density in each of the columns
Data Source
AI summary
The invention relates to a method for improving the consistency of the color density over the printing width of an inkjet printer (10) comprising the steps of:Printing a 2-dimensional pattern (32), wherein the 2-dimensional pattern (32) has the same nominal print density over a printing width and varying nominal print densities in printing direction;Dividing the 2-dimensional pattern (32) in multiple columns (38) across the printing width;Recording with a camera (24) at least one color value for each nominal print density in each of the columns (38);Deriving a correction curve for each column (38) from the recorded color values; and Correcting printing signals and/or printing patterns with the correction curves.Furthermore, the invention relates to an inkjet printer (10).