UV LED Emitter Condensation Prevention in Printing Machines
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Solution Overview
Problem
UV LED emitters in curing devices face condensation issues when not in use, leading to inadequate curing or damage due to moisture condensation on inactive modules, especially when switching between different substrate formats.
Innovation Solution
Operating UV LED emitters in a temperature control mode with a lower power than the curing mode to prevent condensation, ensuring the LEDs remain above the dew point temperature, even when not actively curing, by using a separate or shared coolant circuit with controlled power distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If UV LED emitters are switched off when not in use to save energy, then energy consumption is reduced, but condensation forms on the cooled modules leading to inadequate curing or damage
Solution Approach 1:
The system dynamically adjusts the operating state of UV LED modules based on real-time conditions. Instead of simply switching modules off, the control unit enables a temperature control mode that maintains modules above dew point temperature while consuming minimal energy, thus preventing condensation and ensuring reliable operation when modules are reactivated.
Solution Approach 2:
The invention changes the operational parameters of UV LED modules from binary (on/off) to a three-state system (curing mode, temperature control mode, off). By adjusting the power level to a low but non-zero value in temperature control mode, the system maintains thermal conditions that prevent condensation while minimizing energy consumption.
2Device complexity
If all UV LED modules are fluid-cooled together to ensure proper operating temperature, then temperature control is simplified, but moisture condenses on modules that are switched off
Solution Approach 1:
The control unit monitors the operational state of each UV LED module and provides feedback control for the cooling system. When a module is switched off or in temperature control mode, the system adjusts its cooling accordingly, preventing excessive cooling that would lead to condensation. This feedback mechanism allows the use of a shared cooling system while avoiding the condensation problem.
Solution Approach 2:
The system takes preliminary action by maintaining modules above dew point temperature even when not in curing mode. The control unit anticipates potential condensation issues and preemptively adjusts the power level to prevent condensation before it occurs, ensuring modules are ready for immediate use without damage.
3Adaptability or versatility
If UV LED modules are restarted after being switched off to handle different substrate formats, then adaptability is improved, but the modules may have insufficient curing effect or be damaged due to condensation
Solution Approach 1:
The system dynamically adapts to different substrate formats by selectively activating required UV LED modules while maintaining others in temperature control mode. This dynamic approach allows rapid reconfiguration for different formats without the risk of condensation damage, as modules remain in a protected thermal state during transitions.
Solution Approach 2:
The invention provides beforehand cushioning by maintaining modules above dew point temperature during periods when they are not actively curing. This protective measure cushions against the harmful effects of condensation that would otherwise occur during format changes, ensuring modules can be rapidly reactivated without damage or performance loss.
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
Prevents unwanted condensation and maintains the effectiveness of UV curing processes by keeping UV LED emitters free from moisture, ensuring consistent performance and extending their lifespan.
Implementation Method 1
the fluid is cured by UV radiation emitted by at least one fluid-cooled first UV LED emitter of the device
Implementation Method 2
the fluid, at least its polymerizable portion, is polymerized
Implementation Method 3
at least one fluid-cooled first UV LED emitter
Implementation Method 4
jointly fluid-cooled
Implementation Method 5
the temperature of the emitter is controlled during the interruption by using a heating element
Implementation Method 6
water, e.g. moisture from the ambient air, may condense on the cooled modules
Data Source
AI summary
A method for operating a UV curing device in a printing machine includes providing a printing material to which a UV-curing fluid or UV printing ink or varnish is applied. The printing material is paper or foil moving in a transport direction and having a width. The fluid is cured by UV radiation emitted by a fluid-cooled first UV LED emitter of the device at least in an effective range thereof. The first UV LED emitter is operated in a curing mode and at a first power, and a fluid-cooled second UV LED emitter is operated in a temperature control mode different than the curing mode and at a second power lower than the first power and different than zero. The second power and the temperature of an LED array of the second UV LED emitter is selected to cause the LED array to be free from condensate.