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UV Inkjet Maintenance

(December 2011) posted on Wed Jan 25, 2012

Taking care of your printer’s curing system is neither difficult nor time consuming, but proper monitoring and maintenance must be priorities if you want to realize the full benefits of this technology.

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By Screen Printing's Solution Sourcebook

Wide-format UV inkjets come in models that can print on thick and rigid materials, combination systems for both flatbed and roll-to-roll printing, and flexible, roll-fed media. Regardless of the configuration of these devices, all of them share the distinguishing feature of printing with UV inks, which are cured with specially designed lamp assemblies.

Inkjets with one curing assembly (a typical assembly consists of a single lamp and reflector) print in a unidirectional fashion, and the assembly is mounted on the trailing edge of the printhead to cure inks immediately after they’re jetted onto the substrate. Systems that have two sets of curing lamps position them on both sides of the printhead carriage. Such systems can run in bi-directional mode, with each lamp activated only when it’s on the trailing edge of the printhead.

Some dual-lamp printers can activate lamps to cure on the leading edge so that ink that is laid down is cured only after the carriage returns, not immediately upon deposition. The time between ink deposition and curing can affect the visual characteristics of the final print, which is why curing on the leading edge is referred to as glossy mode on some printer models, and curing on the trailing edge is termed matte mode. The function of the UV lamp is the same regardless of whether a machine cures on the leading or trailing edge of the printhead.

Maintenance and troubleshooting
Parts of the UV-curing assemblies—UV lamps, reflectors, and air filters—require periodic cleaning and replacement. Each manufacturer has a schedule for you to follow. Some may specify a reflector change at each lamp change; others may tell you to change the reflector every other time you change the lamp. Some printers use an all-in-one cartridge system that contains both the lamp and reflector. With such systems, users can remove the cartridge and insert a new one into the assembly housing when the lamp is no longer suitable for curing.

Most manufacturers say that a UV lamp’s average life span is 1000 hours, plus or minus 200 hours. Some substrates require 100% output from the lamps for printed images to cure properly, and frequent job runs on such materials may reduce the effective life of the UV lamps. Conversely, high-volume work with less demanding substrates can prolong the usefulness of the curing lamps because they may not require that the lamps be operated at full power.


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