Shutter Cylinder for Printhead UV Protection
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Solution Overview
Problem
Conventional inkjet printing systems for containers face issues with ink residues and aerosols hardening at the nozzles due to direct UV exposure, leading to clogging and reduced print quality, especially when printing three-dimensional bodies like bottles, and existing solutions are complex, costly, and prone to failure.
Innovation Solution
A shutter cylinder with rotating openings is used to separate the print heads from UV radiation, allowing for fast and cost-effective partitioning during treatment, with openings strategically placed to prevent UV light from reaching the nozzles during printing and allowing UV illumination during ink hardening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the print head is moved closely past the substrate to be printed, then printing precision is improved, but UV light can directly or indirectly reach the nozzles causing ink to harden and clog the nozzles
Solution Approach 1:
The device is divided into distinct functional zones: a printing zone where the print head operates close to the substrate, and a UV treatment zone where UV light cures the ink. A shutter mechanism physically separates these zones, allowing the print head to be positioned closely for precision printing while blocking UV light from reaching the nozzles during the curing process.
Solution Approach 2:
A shutter is introduced as an intermediary element between the UV light source and the print head nozzles. This shutter acts as a controllable barrier that can be positioned to block UV light from reaching the nozzles during ink curing, while allowing unobstructed access during printing operations.
2Reliability
If a nozzle flap or piston system is used to shield nozzles from UV light, then nozzle protection is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
Instead of providing individual shutter mechanisms for each nozzle, the invention uses a single common shutter that protects all nozzles simultaneously. This merged approach maintains reliable UV light blocking for all nozzles while dramatically reducing the complexity and cost of the closure system compared to individual nozzle-level actuators.
Solution Approach 2:
The common shutter serves multiple nozzles simultaneously, providing universal protection across the entire print head array. This multi-functional element replaces what would otherwise require multiple separate components, simplifying the overall system architecture.
3Reliability
If the container is moved into a position without line of sight to print heads after printing, then nozzle protection is improved, but printing productivity decreases due to extended process time
Solution Approach 1:
The shutter operates periodically, switching between open and closed states in synchronization with the printing and UV curing cycles. During printing, the shutter is open to allow precise printing; during UV curing, the shutter closes to protect the nozzles. This periodic operation enables both high-quality printing and nozzle protection within a continuous efficient process.
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 prevents nozzle clogging and maintains print quality by shielding the nozzles from UV radiation during printing while allowing efficient UV curing of the ink, reducing operational complexity and costs.
Implementation Method 1
at least one radiation source (12) for generating electromagnetic radiation (13), in particular UV light
Implementation Method 2
the ink is treated after it has been ejected by means of electromagnetic radiation, in particular by means of UV light (ultraviolet light), as a result of which the ink hardens and can no longer run
Data Source
Figure 1
Figure 2a~2b
AI summary
A sealing device for printheads (11) and/or radiation sources (12) for generating electromagnetic radiation, such as UV light, is described for a system for printing on containers, such as bottles, wherein the container (10) is first printed by at least one printhead (11) by spraying ink from nozzles (13) of the printhead (11) onto the container (10), wherein the generated printed image is subsequently treated by emitted radiation, and wherein the sealing device shields the nozzles (13) from the emitted radiation during the treatment.The closure device comprises a shutter cylinder (1) for receiving the at least one container (10), wherein the shutter cylinder (1) has a side wall (2) that surrounds the container(s) (10), the side wall (2) having at least one opening (8, 9) for printing on the container (10) or containers (10) arranged inside the shutter cylinder (1) through the opening (8, 9) and for irradiating the container (10) or containers (10) arranged inside the shutter cylinder (1) through the opening (8, 9), and the at least one opening (8, 9) being arrangable either in front of the print head (11) or in front of the radiation source.