Tablet Printing Apparatus Suction Control for Inkjet Nozzle Clogging
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Solution Overview
Problem
The existing tablet printing apparatuses face issues with airflow generated by air suction, which causes ink to dry quickly, leading to nozzle clogging and print quality reduction, especially when using an inkjet print head.
Innovation Solution
The apparatus employs a conveyor system with a suction force adjustment mechanism, reducing the suction force in areas where the print head operates to minimize airflow and maintain tablet stability during printing, ensuring consistent ink ejection and improved print quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If air suction is applied to hold tablets during printing, then tablet stability is improved, but airflow causes ink to dry quickly and reduces print quality
Solution Approach 1:
The suction force is adjusted locally based on the tablet's position during the printing process. When the tablet is in the printing area, the suction force is reduced to minimize airflow that would cause ink to dry quickly. When the tablet is in other areas (loading, unloading, conveying), normal suction force is applied to maintain tablet stability. This local adjustment resolves the contradiction by providing different suction levels for different operational phases.
Solution Approach 2:
The suction force is made dynamic rather than static. The control unit continuously adjusts the suction force based on real-time position information of the tablet. When the tablet enters the printing area, the suction force is automatically reduced; when it leaves, the suction force is restored. This dynamic adjustment allows the system to maintain tablet stability when needed while minimizing harmful airflow during printing.
2Force
If strong air suction is used to prevent tablet shifting, then tablet holding is improved, but ink ejection is disrupted due to airflow
Solution Approach 1:
The suction force is applied periodically rather than continuously throughout the entire tablet cycle. The control unit reduces suction force during the printing phase and restores it during other phases. This periodic modulation of suction force ensures that ink ejection is not disrupted by strong airflow during printing, while tablet holding is maintained during conveying and positioning phases.
Solution Approach 2:
The suction force parameter is dynamically changed based on the operational phase. The control unit adjusts the suction force level: high during loading/conveying/unloading phases to ensure tablet holding, and low during the printing phase to ensure reliable ink ejection. This parameter change resolves the contradiction between maintaining tablet holding force and ensuring ink ejection reliability.
3Measurement precision
If air suction is applied to hold tablets, then tablet positioning is improved, but nozzle functionality deteriorates due to ink drying
Solution Approach 1:
The suction force is locally adjusted in the printing area where the harmful effect occurs. The control unit detects when the tablet is in the printing area and reduces suction force at that specific location, minimizing airflow that would cause ink to dry quickly. In other areas, full suction force is maintained to ensure accurate tablet positioning and holding.
Solution Approach 2:
The control unit takes preliminary action by reducing suction force before or as the tablet enters the printing area, preventing the harmful effect of ink drying from occurring in the first place. This anticipatory adjustment of suction force protects the ink ejection process from the harmful effects of strong airflow while maintaining positioning precision during other phases.
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
This solution effectively reduces airflow-related defects, maintains inkjet nozzle functionality, and enhances overall print quality by stabilizing the tablets during the printing process.
Implementation Method 1
the conveyor is configured to convey tablets sequentially supplied while sucking and holding the tablets
Implementation Method 2
When the airflow reaches the nozzle that ejects ink, the ink in or around the nozzle tends to dry quickly
Data Source
AI summary
According to one embodiment, a tablet printing apparatus includes a conveyor configured to convey tablets sequentially supplied while sucking and holding the tablets; a print head arranged to face the conveyor to perform printing on each of the tablets being conveyed; a detector arranged upstream of the print head to detect the posture of each of the tablets; and a print condition tester arranged downstream of the print head to check print condition on each of the tablets. Suction force applied to the tablets is reduced at least in an area from a detection position to a print condition check position than in other area.