Digital Printing of Phosphorescent Particles

Abstract

Phosphorescent (afterglow) particles are commonly used for safety and security applications, utilizing their ability to glow even after the stimulating energy source is removed. Fields-ofapplication are marking of safety and rescue equipment, escape routes and exit doors. They work at worst environmental conditions such as a power breakdown or smoke. For these applications screen printing is the commonly used printing method. However, especially for small batch sizes or personalized solutions, digital printing methods are desirable. In this paper, two digital printing technologies are presented. Inkjet printing is a contact-free method that allows for printing on textured and/or sensitive substrates. Printing of particles with several micrometers diameter is possible under appropriate conditions. Here, the size of the particles is a limiting factor. Electrophotography, commonly known as laser printing, allows application of larger particles. However, this method is not contact-free and limited by the choice of possible substrates. Both methods compete with each other in printing velocity and scalability, but they also complement each other in the applicable particle size and substrate choice.This paper investigates the possibility of printing phosphorescent particles, by using afterglow particles from Honeywell as an example. The Lumilux SN-F5 particles have a diameter of about 6 μm and are printed with both technologies.