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Frequently Asked Questions

Q: We have a lamp but we don't know what type, can Primarc supply it?

A: We manufacture Primarc uv curing lamps for all makes of dryer/curing systems. We can develop manufacturing specifications from an original operating sample and technical data that may be available.  In the first instance, simply fill in the Lamp Identification Sheet and email or fax it to us for identification.

Q: We have a lamp that seems to be the same size as another. Will it work in another machine?

A: It depends. The length of a lamp is usually a result of the size of the media that is being printed or coated. However, each lamp is designed for the drying/curing system into which it is installed. Therefore, one lamp may not work for another because its electrical characteristics and termination features may differ from another lamp. Review your requirements with Primarc and we will help you determine the ability of a lamp to work in different machines.

Q: Can Primarc make a higher power lamp than we already have and upgrade?

A: Power supplies and UV lamps are usually designed and matched to provide optimum performance. The lamp is cooled in a specially designed lamp head, which should provide an appropriate cooled environment for reliable lamp operation. Usually, upgrading would require both the lamp and power supply to be replaced, and additional modifications to the lamp head to provide an appropriate environment. Please contact our Technical Department for advice.

Q: Can we have a standard lamp with additive to enhance output?

A: Simply adding a metal halide to a lamp will not enhance output. The electrical system for this enhanced lamp must be matched to the lamp so that the proper amount of striking and operating voltage are available to introduce the halide into the plasma stream.

Q: What guarantee do I get with the lamp?

A: Primarc lamps are manufactured to the highest standards and will provide a useful UV life of up to over 1500 hours under normal conditions, unless otherwise stated. In the unlikely event of failure, and depending upon the cause of failure and the model, pro-rata credit may be given in relation to the shortfall from the guaranteed period at the time of failure.

Q: What is the lump of solder in my lamp?

A: What appears to be a lump of solder is actually a precise quantity of mercury. In a mercury-vapour curing lamp, mercury is energized into plasma where it generates specific wavelengths of ultraviolet energy, which are used to initiate the polymerization of UV curable inks and coatings.

Q: What is the lump of glass on the lamp tube?

A: What appears to be a lump of glass is actually a closed seal, commonly referred to as the "Pip" or "Fill Tip”.  This is the result of our lamp manufacturing process using technology designed to produce a more reliable and consistent performance. It does not affect the UV output or the lifetime of the lamp.  

Q: What are the recommended running temperatures for a UV curing lamp?

A: The area between the tips of the electrodes, within the main lamp body, should be maintained at an operating temperature of 600 - 800 degrees C. The area consisting of the metal foil and end fitting should be maintained at a temperature of less than 250 degrees C. If the lamp has an electrical lead-out wire, the wire must be maintained at a temperature of less than 200 degrees C.

Q: How do I properly dispose of a lamp since it contains mercury?

A: UV lamps must be disposed of in accordance with environmental legislation.  Please contact Primarc for advice.



Possible Cause


Media not being cured effectively










Dryer reflectors are dirty or not focused correctly

Clean or re-focus reflectors. 

External contamination of lamp


Clean lamp of external contamination, such as spray powder or other contaminants.

Photoinitiator material not equally distributed as coating and ink material not correctly mixed.


Confirm that all coating and ink material has been stirred to homogeneity before application so that all of the photoinitiator material is equally distributed.

Lamp has overrun hours of effective usage 


Verify the number of operating hours that the lamp has run. Different applications result in different lamp lifetimes. Lamps generally have an energy output of about 80% of their original specification after 1000 hours, provided that the lamp is operated in an appropriate environment. If the lamp has over 1000 hours of use, it may not generate enough ultraviolet energy for curing your application

Lamp is bowed or looks like a banana


Lamp has been overheated


The lamp must be in a cooled and controlled environment where the surface temperature of the lamp body should be at a temperature of between 600 - 800 degrees C. If the air around the lamp is not conditioned properly, this temperature will rise causing the quartz tube to soften and lose its rigidity. Adjust the cooling and airflow around the lamp to reduce the temperature of the lamp body and check condition of reflectors.  However, ensure that the lamp body is not cooled below 600 degrees C, as below this temperature could lead to mercury condensing out of the plasma, which will effect lamp power and performance.

Lamp ignites but will not achieve full intensity.

Too much cooling – mercury condensed behind electrodes.

Check cooling system

New lamp will not ignite.


Terminations loose.

Confirm all terminations are tight.

Power supply fault.

Seek advice from equipment supplier.

Lamp fault.

Replace lamp

Lamp is discoloured.

1. Black ends

2. Clouding

3. Mirror coated


There is natural “blackening” of the quartz tube at each end during the life of the lamp. This is the result of the electrode material depositing on the inside of the tube during its use.

Replace lamp


Natural solarisation or clouding of quartz occurs as the quartz reverts to its natural crystalline structure, which is opaque to ultraviolet energy

Replace lamp


Overcooling results in mercury being deposited on the inside of the lamp giving it a mirror-coated affect

Replace lamp


External devitrification

(“Cloudy” quartz surface)


Ink, cleaning solution or finger mark has burnt in on a hot lamp, the arc is diverted to the polluted spot and burns a hole in the tube causing loss of vacuum.

More caution with lamp changing and/or cleaning.

Lamp is tripping-out (arcing against the reflector or machine).


As UV lamps usually operate at high voltages it is possible that if the tube is in close proximity to the lamp head arcing can occur.  This mode of failure is also sometimes characterised by the presence of a pinhole in the tube.

Check that the lamp is correctly located and that the reflectors are not distorted.


Orange discoloration inside the tube.

Lamp has mechanical break (leak) whilst burning.

Replace lamp.