Impingement Jet Cooling for Printing Transport Stability
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Solution Overview
Problem
Existing cooling devices in inkjet printing machines are inadequate in managing high heat input from dryers, leading to thermal expansion and disruptions in the printing process, and are often costly to enhance cooling performance.
Innovation Solution
An impingement jet blowing device is used for near-field cooling, providing high-speed air at a low volume flow to effectively cool transport devices, such as cylinders, while integrating with existing air supply systems to reduce costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the volume flow and cooling capacity of the blowing device are increased to achieve sufficient cooling performance, then the cooling effect is improved, but the costs increase due to additional fans and heat exchangers
Solution Approach 1:
The patent changes the parameters of the air flow by increasing the air velocity to supersonic or near-supersonic speeds (Mach 0.3 to 1.2) while maintaining a low volume flow. This parameter change allows achieving high cooling performance without increasing the size or complexity of the cooling device, thus resolving the contradiction between cooling effectiveness and device complexity/costs
Solution Approach 2:
The patent employs pneumatic principles by using a jet of compressed air delivered through a nozzle to create the cooling effect. The high-velocity air jet generates a cooling plume that effectively removes heat from the substrate without requiring large volumes of air or additional mechanical cooling components, thereby reducing device complexity and costs while maintaining high cooling performance
2Device complexity
If a blowing device with open blowing box is used, then the device complexity is low, but the cooling performance is insufficient when there is very high heat input from heat dryers
Solution Approach 1:
The patent maintains device simplicity by using a straightforward nozzle-based blowing device without complex structures, but achieves high cooling performance by changing the air velocity parameter to supersonic or near-supersonic speeds. This creates a high-velocity jet that generates an effective cooling plume, resolving the contradiction between device simplicity and cooling performance
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 achieves improved cooling performance with up to a fivefold increase compared to traditional blowing devices, maintaining a stable printing process while minimizing additional equipment and energy consumption.
Implementation Method 1
The impingement jet blowing device is used for near-field cooling. Such cooling can achieve an improved cooling performance of up to a factor of 5 compared to a blowing device with an open blowing box. When using the so-called impact jet principle to cool the transport device, the transport device is supplied with blown air at high speed, for example 50 to 90 m/s
Implementation Method 2
The air outlet from the impingement jet blowing device is preferably carried out through a plurality of small openings or nozzles, instead of from a single, large opening of the blowing device, for example with a diameter of 0.5 to 5 mm. The impingement jet blowing device is preferably arranged close to the transport device to be cooled, for example at a distance of 3 to 30 mm
Data Source
Figure 1
Figure 2~3
AI summary
The invention relates to a machine for producing printed products, comprising a printing unit (3) for printing on a substrate (2), a dryer (4) for drying the printed substrate, a transport unit (5) for transporting the substrate, and a blowing unit (6) for cooling the transport unit, and is characterized in that the blowing unit is designed as an impact jet blowing unit (6). The invention advantageously provides sufficient cooling for uninterrupted printing and thereby avoids or reduces costs.