A residual amount management device for managing a residual amount of a printing consumable for a print device, the print device including:
- a tank configured to store a printing consumable supplied from a storage body having a predetermined capacity for storing the printing consumable;
- a level sensor configured to detect whether a level of the printing consumable in the tank is higher than or equal to an upper reference level;
- and a print engine configured to perform image formation on a printing medium by using the printing consumable in the tank, the upper reference level corresponding to the level of the printing consumable in the tank when an entire amount of the printing consumable corresponding to the predetermined capacity is supplied into the tank in an empty state,
- the residual amount management device being configured to perform:
- a printing amount obtaining process including:
- obtaining printing-amount information indicating a printing amount of the printing consumable consumed by the image formation using the print engine;
- a first determining process after detection, by the level sensor, that the level of the printing consumable in the tank has decreased from at or above the upper reference level to below the upper reference level, the first determining process including:
- determining whether an estimated residual amount reaches a first threshold value, the estimated residual amount being calculated based on the printing-amount information obtained in the printing amount obtaining process;
- a second determining process after the detection, by the level sensor, that the level of the printing consumable in the tank has decreased from at or above the upper reference level to below the upper reference level, the second determining process including:
- determining whether the estimated residual amount reaches a second threshold value;
- a printing prohibiting process in a case where the estimated residual amount is determined to reach the second threshold value in the second determining process, the printing prohibiting process including:
- prohibiting the image formation using the print engine;
- a third determining process in response to detection, by the level sensor, that the printing consumable has increased from below the upper reference level to at or above the upper reference level after the estimated residual amount is determined to reach the first threshold value in the first determining process, the third determining process including:
- determining that the entire amount of the printing consumable in the storage body is supplied into the tank;
- and
- a printing allowance process in a case where the estimated residual amount is determined to reach the second threshold value in the second determining process and the printing prohibiting process is performed, and thereafter the entire amount of the printing consumable in the storage body is determined to be supplied into the tank in the third determining process, the printing allowance process including:
- allowing the image formation using the print engine.