Inkjet Printing Head Dynamic Discharge Control for Nozzle Inspection
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Solution Overview
Problem
Existing ink-jet printing devices face reduced detection accuracy when the color difference between the printing sheet and ink is small, making it difficult to perform effective inspections using test patterns.
Innovation Solution
A printing device and method that adjust the discharge amount of ink based on the color difference between the test pattern and the medium, discharging a higher amount when the color difference is small to enhance detection accuracy, using a control unit to manage the discharge from nozzles during relative movement with respect to the medium.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a standard discharge amount of ink is used for test pattern printing, then the printing process is simple and fast, but the detection accuracy is reduced when the color difference between the printing sheet and ink is small
Solution Approach 1:
The patent applies dynamics by making the discharge amount adjustable based on detected color difference. The control unit dynamically selects between a first discharge amount (for large color differences) and a second discharge amount (for small color differences), transforming a static printing process into a dynamic one that adapts to different inspection conditions to optimize detection accuracy.
Solution Approach 2:
The patent changes the discharge amount parameter based on the color difference between the printing sheet and ink. When the color difference is small, a larger second discharge amount is used to enhance pattern visibility and detection accuracy. When the color difference is large, a smaller first discharge amount suffices, preventing excessive ink usage and maintaining process simplicity.
2Measurement precision
If a larger discharge amount of ink is used, then the pattern formation is stronger and detection accuracy improves, but the risk of interference between adjacent patterns increases
Solution Approach 1:
The patent applies local quality by providing different discharge amounts for different inspection scenarios. The second discharge amount (larger) is locally applied only when color difference is small and detection accuracy is compromised. The first discharge amount (smaller) is used when color difference is already large, preventing unnecessary pattern interference. This localized adjustment optimizes detection without causing harmful interference.
3Measurement precision
If the discharge amount is adjusted based on color difference, then detection accuracy is improved, but the control complexity increases
Solution Approach 1:
The patent implements feedback by using the color difference detection result to control the subsequent discharge amount selection. The control unit receives feedback about the color difference (comparing printing sheet color with ink color) and automatically adjusts the discharge amount accordingly, creating a closed-loop control system that improves detection accuracy without requiring complex manual intervention.
Data Source
AI summary
A printing device comprising a printing head including a plurality of nozzles configured to discharge ink to a printing medium are arranged, and a control unit configured to control discharge of the ink. The printing head is configured to discharge the ink along with scanning that is a relative movement in a predetermined direction with respect to the printing medium, and in test printing for printing a TP on the printing medium, the control unit performs control such that the ink of a first discharge amount is discharged from the nozzles when a color difference between the TP and the printing medium is greater than a predetermined threshold value, and the ink of a second discharge amount that is greater than the first discharge amount is discharged when the color difference between the TP and the printing medium is equal to or smaller than the threshold value.