UV and UV-LEDs for Inkjet Printing
Headquaters Dr. Hönle AG 40 years UV experience / 15 years inkjet experience Turnover 93 Mio Euro / 550 employees More than 8.000 UV systems for inkjet in operation Exclusive supplier for main providers Gräfelfing / Munich
UV /UV-LED Technology for Inkjet Applications Environmental friendly technology due to Solvent / VOC free inks Less energy consumption for curing / drying Instant on/off of UV-LEDs helps to save energy and life time Increased quality due to Sharp drops through instant curing No paper curling or wrinkling Improved chemical and mechanical resistance of inks
What is UV Curing? UV lamp Liquid coating or ink Rigid coating or ink Photoinitiators absorb UV irridiation Creation of free radicals Cracking double bonds Start of polymerisation forms a three-dimensional network inside the coating or ink
UV Curing Technology UV-Strahlung im elektromagnetischen Spektrum Gamma-Rays Radiowaves Microwaves X-Rays Infra Red 9 8 6 5 4 3-1 7 2 1 0-2 -3 Irradiation Energy ev -6-5 -4-2 -1 0 1 5 6 Wavelength -3 2 3 4 nm UV Visible light VUV UVC UVB 0 200 300 400 500 600 700 Wavelength nm Medium pressure UV lamp LED-UV lamp
UV Curing Technology Conventional UV Function and spectrum Quartz tube Socket Electrodes Pinch Gas filling Current duct 0 90 80 70 60 50 40 30 20 0 Spectrum standard Hg (mercury) 200 300 400 500 600 700 Wavelength [m]
Properties of Conventional UV Lamps Well-known technology Emits total UV spectrum from 200 to 400 nm (UVC for surface curing) Various spectra (Hg, Fe, Ga...) available Ozone-free bulbs Economic solution Systems are available from 0 to 2600 mm length and up to 300 W/cm power Easy control of lamp Easy bulb change, maintenance Wide range of chemistry available, incl. packaging applications
jetcure UV Conventional UV system, available with all spectra Power up to 240 W/cm External or internal fan Focused reflector generates very high intensity 17 mm under the lamp housing Dichroic reflector for IR reduction Slot for easy lamp change
Hier fehlt eine Überschrift UV LED Function and spectrum Photons P-Layer N-Layer LIGHT is emitted as soon as voltage is applied. LED-Spectrum- relative Intensity 0 80 60 40 20 365nm 385nm 395nm 405nm 0 350 360 370 380 390 400 4 420 430 440 wavelength [nm]
Properties of UV-LEDs Compact design, low weight for small space requirements, e.g. 3D High UV intensity at specific wavelengths No direct infrared irradiation on substrate Single segments can be switched off No heat-up immediate lamp on possibility for intermediate operation Energy efficient, e.g. during job change LED effectiveness: wavelength related > 40% No ozone production Typical lifetime > 20.000 hours under recommended operation and environmental conditions
Hönle s LED History 2005 Start of UV-LED production at Hönle 2006 First use of LED spot curing for UV-reactive adhesives 2008 Increasing interest for UV-LEDs at drupa 2009 Development of LED Spot and LED Powerline 2013 Air-cooled with up to 8 W/cm² and high power water-cooled LEDs up to 20 W/cm² 2014 LED powerline Offset and Flexo, up to 25 W/cm² water-cooled 2017. jetcure LED for inkjet, air-cooled 16 W/cm 2
Variety of UV-LEDs for Printing and Coating.000 UV-LEDs have been sold since 2006 air-cooling water-cooling 6.000 4.000
UV-LED Systems for Printing Applications jetcure LED LED Powerline Focus LED Powerline AC/IC + LED powerdrive IC Modularer Aufbau LED Powerline LC
LED Powerline AC/IC for Single Pass Air-cooled system with 4 or 8 W/cm² Various wavelengths available (365, 385, 395 or 405 nm) Width in curing direction or 20 mm Modular system with 120 mm width profi-jet GmbH and profi-tec GmbH
Intensity [W/cm²], Dose [J/cm²] jetcure LED for Wide Format Inkjet Printing Air-cooled system Various wavelengths available (365, 385, 395 or 405 nm) Length depends on application (82-656 mm in 82 mm grids) Individual control of LED segments Intensity up to 16.000 mw/cm² Low temperature load jetcure LED 330 AC/IC 395 nm 18 16 14 12 8 6 4 2 0 UVV Intensity UVV Dose 6m/min 5 15 20 25 30 35 40 45 50 55 60 Working distance [mm]
Intensity [mw/cm²] LED Powerline for Final Curing Various wavelengths available (365, 385, 395 or 405 nm) Water-cooled system Length depends on application Small space requirement High intensity of up to 25 W/cm² 16000 14000 12000 000 8000 6000 4000 2000-0 y-dimension -45-39 -33-27 -21-15 -9-3 3 9 15 21 27 33 39 45 x-dimension profi-jet GmbH and profi-tec GmbH
What do We Need to Know to Find the Right LED Solution? Process: Chemistry: Line requirements: Conventional UV curing or UV-LED curing? Single-pass or multi-pass? Pinning or final curing? Which ink or coating is used? Which wavelength is best (365, 385 or 395 nm)? If unknown, we can run trials in the lab to indentify the right wavelength How much intensity and dose does the ink need to cure? If unknown, we can run trials in the lab to indentify the required curing conditions. How much space is available in the curing area? Is water-cooling possible? Which line speed / curing time should be reached?
Identify the Right Wavelength Photoinitiators absorb UV at various wavelengths. The emission of the UV-LED and the absorption of the photoinitiator need to overlap. 0 80 LED spektrum - relative intensity 365nm 385nm 395nm 405nm 60 40 20 0 350 360 370 380 390 400 4 420 430 440 Wavelength [nm] Once the production has started, the LED wavelengths cannot be changed anymore. Therefore it is important to identify the right wavelength at the beginning of the project.
Trials Report to Identify the Optimal Wavelength Wavelength 365 nm 385 nm 395 nm 405 nm Intensity [mw/cm²] (2mm) 9471 (UVA) 17.517 (UVA2) 17.209 (UVA2) 18.940 (UVV) Distance [mm] Line speed [m/min] 50 50 50 50 Power [%] 0% 60% 60% 50% Isoprop immediatly 32 45 52 36 FTIR 8/1720cm-1 [% zu nass] 65 71 74 70 Surface soft Slightly tacky hard Slightly tacky Recommended wavelength
Inkjet Label Printing and Coating Applications
UV equipment and systems UV lamps UV measuring UV adhesives Process development Thank you for your attention. Please, join us at booth 328. www.hoenlegroup.com