Printing device and printing system

A printing device comprising:

• a cartridge mounting unit that allows a plurality of cartridges to be attached and detached;
• an ejection head including a plurality of nozzles configured to eject a liquid stored in each of the plurality of cartridges;
• and
• a controller, wherein
• a predetermined flat-rate usage fee is applied to the printing device regardless of the number of times the cartridge is replaced, wherein
• the controller includes
• a cleaning execution unit that executes a cleaning process including a cleaning operation of sucking and flowing out the liquid from the nozzles for all of the plurality of cartridges when a predetermined cleaning condition is satisfied and
• a remaining amount acquisition unit that acquires a liquid remaining amount of each of the plurality of cartridges, and wherein
• the cleaning process includes
• a determination process of determining presence or absence of a specific cartridge, among the plurality of cartridges, in which the liquid remaining amount that is equal to or greater than a predetermined reference remaining amount, and the liquid remaining amount is expected to be less than the reference remaining amount when the cleaning operation is executed, the determination process being executed before the cleaning operation is executed, and
• a setting process of setting the specific cartridge as a cartridge to be replaced before executing the cleaning operation when it is determined by the determination process that the specific cartridge is present.