Adaptive Sheath Flow Nozzle for Print Quality
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Solution Overview
Problem
Existing powder sprayer systems with sheath flow nozzle arrangements in printing presses face challenges in maintaining consistent print quality, particularly when processing paper sheets, as the momentum of the support air jacket flow causes fluttering, leading to smearing of freshly printed images.
Innovation Solution
The method involves controlling the bypass nozzle arrangement based on operating parameters such as sheet grammage and printing mode, allowing for adaptive air loading and delivery speed adjustments to optimize the air impingement for different print jobs, ensuring stable sheet travel and high print quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the support air jacket flow momentum is increased to stabilize sheet travel for cardboard sheets, then sheet stability is improved, but paper sheets experience excessive fluttering and image smearing
Solution Approach 1:
The air loading of the sheath flow nozzle arrangement is made dynamically adjustable through a control device that modifies operating parameters (air pressure, delivery speed) based on detected sheet properties such as grammage or sheet format, allowing optimal adaptation to different sheet types
Solution Approach 2:
The control device changes physical parameters of the air flow (pressure, delivery speed, air loading) according to detected operating conditions, transitioning from fixed parameters to variable parameters that adapt to different sheet characteristics
2Device complexity
If a fixed air loading is used in the sheath flow nozzle arrangement, then device complexity is reduced, but print quality varies across different print jobs and sheet types
Solution Approach 1:
A control device with detection means (for sheet format, grammage, or other operating parameters) provides feedback to automatically adjust the air loading of the sheath flow nozzle arrangement, ensuring optimal performance across different print jobs without manual intervention
Solution Approach 2:
The control device automatically detects operating parameters and self-adjusts the air loading without requiring manual intervention for each print job, making the system self-adapting to different sheet types and conditions
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 approach ensures consistently high print quality by optimizing the air loading and delivery speed of the sheath flow nozzle arrangement according to varying sheet grammages and printing modes, preventing sheet fluttering and image smearing.
Implementation Method 1
nozzle heads arranged in a row, each nozzle head having two nozzles, from each of which a jet of powder air emerges. A blowpipe is arranged above the nozzle heads, from which jets of compressed air emerge. The delivery speed of these compressed air jets is about twice as high as that of the powder air jets. The compressed air jets together form a powder-free support air jacket flow that surrounds the powder air jets on all sides.
Implementation Method 2
The support air jacket flow shields the powder air jets from eddy currents, which are caused by the movement of a gripper conveying the printed sheet.
Implementation Method 3
The momentum exerted on the printed sheet by the support air jacket flow is suitable for the cardboard sheets, but too great for the paper sheets. The impulse affects the sheet travel of the paper sheets, which flutter as a result.
Data Source
Figure 1
Figure 2~3
AI summary
The method involves controlling a mantle-stream nozzle arrangement (13) using a control unit (25) based on operating parameters of a printing machine, where the parameters are different printed sheet-grammages. The parameters are adjusted in a face- and reverse printing mode and in a clear face-sided printing mode. Dispensing speed of mantle streams of the arrangement is changed based on the parameters. Dispensing speed of power air-core streams of the arrangement is maintained invariably during the change of the dispensing speed of the mantle streams.