Control Plate Airflow Management for Tablet Inkjet Printing
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Solution Overview
Problem
In tablet printing apparatuses using inkjet print heads, airflow turbulence caused by incomplete suction of tablets on conveyor belts leads to nozzle clogging and reduced print quality due to powder adhesion and misalignment of ink droplets.
Innovation Solution
A control plate is positioned upstream of the print head to control airflow between the conveyor belt and the print head, using comb teeth to block and redirect airflow, preventing powder from adhering to the nozzle surface and maintaining the posture of tablets during printing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a suction type conveyor belt is used to convey tablets, then tablets can be held and conveyed stably, but airflow turbulence occurs when suction holes are not completely closed by tablets, causing powder adhesion to the nozzle and reducing print quality
Solution Approach 1:
A control plate is introduced as an intermediary component between the conveyor belt and print head. The control plate includes a plate body extending in the conveying direction and a blocking portion that protrudes toward the conveyor belt to block airflow. This intermediary structure suppresses turbulence generated by incomplete tablet coverage of suction holes, preventing powder from adhering to the nozzle while maintaining stable tablet conveyance.
Solution Approach 2:
The control plate's blocking portion is designed with multiple segmented structures (protrusions or ribs) that divide and redirect airflow into controlled patterns. This segmentation of the airflow path reduces chaotic turbulence into organized flow patterns, minimizing powder suspension and adhesion to the nozzle surface while preserving the suction functionality for tablet conveyance.
2Manufacturing precision
If the print head is positioned close to the conveyor belt for precise printing, then print resolution improves, but airflow turbulence more easily disrupts tablet posture and causes misalignment
Solution Approach 1:
The control plate serves as a protective intermediary between the print head and conveyor belt environment. By positioning the control plate between these components and using its blocking portion to suppress turbulence, the system maintains stable tablet posture even when the print head is positioned close to the conveyor belt for high-resolution printing.
Solution Approach 2:
The control plate is positioned upstream relative to the print head, creating preliminary anti-action against turbulence before it can reach the tablets. The blocking portion protrudes to counteract airflow disturbances in advance, preventing turbulence from disrupting tablet posture during the critical printing zone, thereby maintaining both print resolution and tablet stability.
3Reliability
If high suction force is applied to hold tablets firmly, then tablet holding reliability improves, but airflow turbulence increases when tablets do not fully cover suction holes
Solution Approach 1:
The control plate acts as an intermediary that addresses the harmful airflow effect without requiring reduction of suction force. The blocking portion intercepts and redirects turbulence generated by incomplete tablet coverage, allowing the system to maintain high suction force for reliable tablet holding while suppressing the resulting airflow turbulence that would otherwise cause powder adhesion.
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
The control plate effectively suppresses powder adhesion to the print head and maintains the posture of tablets, reducing printing failures and improving print quality by rectifying airflow into a laminar flow, thus ensuring accurate ink placement and consistent printing results.
Implementation Method 1
A plurality of suction holes of, for example, circular or rectangular shape are arranged so as to line up in the conveying direction of the tablets in the conveyor belt of the suction type tablet conveying device to suck and hold the tablets.
Implementation Method 2
a control plate that is located on the upstream side of the print head in the conveying direction of the tablet between the conveyor belt and the height position of the nozzle surface of the print head, and controls an airflow generated between the conveyor belt and the print head
Data Source
AI summary
According to one embodiment, a tablet printing apparatus includes: a conveyor belt that includes a suction hole connected to a suction chamber, and conveys a tablet while sucking the tablet to the suction hole; an ink jet print head that has a nozzle surface where a nozzle is formed, and is located above the conveyor belt such that the nozzle surface faces the conveyor belt, and performs printing on the tablet conveyed by the conveyor belt; and a control plate that is located on the upstream side of the print head in the conveying direction of the tablet between the conveyor belt and the height position of the nozzle surface of the print head, and controls an airflow generated between the conveyor belt and the print head.