Image forming apparatus, image forming method, and computer-readable storage medium

An image forming method performed in an image forming apparatus that includes a print head configured to fire ink droplets, a subtank configured to store therein ink and supply the ink to the print head, a subatmospheric pressure generating unit configured to generate subatmospheric pressure in the subtank, and a main tank configured to supply ink to the subtank, the image forming method comprising:

• detecting an amount of ink in the main tank;
• controlling the subatmospheric pressure generating unit to generate subatmospheric pressure in the subtank and to cause the print head to fire ink droplets when an amount of ink in the main tank is detected to be less than a predetermined first threshold;
• and
• controlling the print head to stop firing ink droplets when a time elapsed after the subatmospheric pressure is generated in the subtank exceeds a predetermined second threshold.

A non-transitory computer-readable storage medium with an executable program stored thereon and executed by a processor of an image forming apparatus that includes a print head configured to fire ink droplets, a subtank configured to store therein ink and supply the ink to the print head, a subatmospheric pressure generating unit configured to generate subatmospheric pressure in the subtank, and a main tank configured to supply ink to the subtank, wherein the program instructs the processor to perform:

• detecting an amount of ink in the main tank;
• controlling the subatmospheric pressure generating unit to generate subatmospheric pressure in the subtank and to cause the print head to fire ink droplets when an amount of ink in the main tank is detected to be less than a predetermined first threshold;
• and
• controlling the print head to stop firing ink droplets when a time elapsed after the subatmospheric pressure is generated in the subtank exceeds a predetermined second threshold.