UV lamp life

[RoCo]

Is the biggest determining factor for the lifespan of UV lamps its eventual inability to completely cure the ink? How about color shift? In other words, would an image cured by brand new lamps match color-wise to the same image cured with older lamps?

Is there a general industry thumb rule on lamp life span? I've been using the same set of UV lamps for quite a bit longer than what the install tech told me they would last, but my ink is still curing just fine - still passes the thumbnail test. At the moment my plan is to run them until one fails or they lose their ability to completely cure the ink. Any thoughts?

 

[CanuckSigns]

I don't run a UV printer, but that makes perfect sense to me, if it ain't broke...

 

[Letterbox Mike]

We're seeing about 600 hours on our CET lamps, near as I can tell.

I just replaced them last week in the middle of a big run, there was no noticeable color difference after new lamps. I didn't realize or notice how much cure banding was present with the old lamps though, so replacing them eliminated that which was a significant improvement.

I also can't really see any difference with adhesion from the old lamps to the new, but I don't think we pushed the old lamps to the brink of failure either, so adhesion may have suffered eventually if we kept them longer.

 

[omgsideburns]

500-600 hours before they are dim enough to cause print artifacts. I've never noticed color shift or adhesion issues though the ink can feel "soft", and banding starts to be more apparent.

In my experience.

 

[Gino]

Our first set we got almost 750 hours. Found out why we had some problems before changing them out. We now change out around 400 to 500 hours. Never saw a color difference, just how well the ink bit into various substrates. We change out about once every two to three months.

 

[uvgerard]

UV lamp (bulb) life depends on many factors including number of starts, thermal operating conditions, power rating, additives and proper handling. Simply defined, it is the hours the lamp produces enough UV energy to properly cure the ink within the available exposure time.
The initial 200 to 250 hours of operation (idol time plus active print time), the UV output is stable. Between 250 and 450 operation hours, output decreases, eventually resulting in insufficient UV curing energy. Some inkjet printers have the ability to change lamp power settings. Switching to medium or high power increases UV output, however heat is also increased. There may be a fine balance between acceptable UV output and heat generation. Another option is to maintain heat loading by slowing print speed while the UV lamp is at low power. This option is mostly available with standard mercury filled lamps. Some lamps are additive filled. They produce higher levels of UV; however, they do not last as long and normally cannot be run at low power.Each lamp startup reduces UV lamp life. Adjust printing schedule to keep lamp starts to a minimum. The fact that that lamp lights is not an indication of proper UV output. Most UV lamps will continue to operate long after their useful life has expired.

In general you should consider 500 hours total operating time as reference lamp life. Remember to reduce gloss banding and maintain equal UV dosage when printing bidirectionally, it is recommended that both UV lamps be replaced at the same time.