The maintenance box collects waste ink produced by the printer during printhead cleaning cycles which occur after print jobs. The frequency with which the maintenance cartridge must be replaced depends upon how often the printer is used and how often the operator runs additional printhead cleaning routines. Use of incorrect labels particularly dusty types caused paper dust to block the print head nozzles and excessive cleaning will cause the maintenance cartridge to fill up more quickly. Once full the maintenance cartridge cannot be emptied, it must be removed and disposed of. The printer will not function once the maintenance cartridge is full so it is essential that a spare unit is kept in stock to avoid downtime.