A Canon -like Lexmark and HP are properly known as Bubblejets.
That is because the print head consists ofmany,many fine tubes[finer than a human fair] in each of which there is a heater[would you believe]
On the command from the PC the approriate heater heats up to produce a spot of steam which edjects the ink.
Evewntually the odd heater fails, and then progressivly gets worse.
The only remedy is head replacement.