XJ128 and XJ128 Plus Printhead
XJ128 Guide to Operation
Xaar Document no: D031010302 Version A
Page 47
8.3.6 Ink Spitting
If a printhead is non-operational for a long period of time and filled with ink; depending upon the ink
chemistry, the ink in the nozzles in contact with the air can change it
’
s nature. This can sometimes
affect performance and in some cases block nozzles. Ink spitting is a technique used to fire the
printheads at a low frequency to allow a continuous flow of fresh ink through the nozzles. This helps
provide a more reliable start up of the printhead. The amount and frequency of spitting is ink and
system dependant and should be determined empirically with each system design.
Ink spitting should not be used as a primary function in order to eliminate the
requirement for regular printhead maintenance. For further information, please contact
your appointed sales engineer.
8.3.7 Capping
Capping is a procedure that protects the nozzle plate from dust and damage whilst the printheads
are non operational. Capping involves designing a cap that fits around the nozzle plate preventing
fresh air and dust from contacting the nozzle plate. Some caps may be filled with solutions to help
prevent the drying out of nozzles when using volatile inks.