Image forming apparatus and method of controlling the same

An image forming apparatus, comprising:

• a photoconductor drum;
• a developing unit including a developing roller configured to form a toner image on the photoconductor drum and a developing unit housing storing toner;
• a toner housing storing toner;
• a controller configured to execute:
• a developing process of developing an electrostatic latent image on the photoconductor drum;
• a usage-amount obtaining process of obtaining a usage amount of the toner;
• and
• a supplying process of supplying the toner to the developing unit housing from the toner housing every time the usage amount of the toner becomes equal to or greater than a supplying threshold,
• wherein, where the supplying threshold is represented as TH1 and a maximum usage amount of the toner for a sheet having a maximum size that can be printed is represented as M, the following expression is satisfied:
• M≤TH1≤2M.

An image forming apparatus, comprising:

• a printer housing;
• a photoconductor drum provided in the printer housing;
• a developing unit provided in the printer housing, the developing unit including a developing roller configured to form a toner image on the photoconductor drum and a developing unit housing storing toner, the developing unit allowing a toner housing storing toner to be mounted, the developing unit having an inlet through which toner is supplied into the developing unit housing from an outlet of the toner housing;
• a toner sensor configured to detect an amount of toner contained in the developing unit housing;
• and
• a controller configured to execute:
• a developing process of developing an electrostatic latent image on the photoconductor drum;
• a usage-amount obtaining process of obtaining a usage amount of the toner;
• a supplying process of supplying the toner to the developing unit housing from the toner housing;
• and
• a detecting process of detecting, by the toner sensor, the amount of the toner contained in the developing unit housing every time the usage amount of the toner becomes equal to or greater than a detecting threshold, and
• a determining process of determining whether or not the detected amount of the toner contained in the developing unit housing is greater than a predetermined amount, so as to prevent the toner from being excessively supplied into the developing unit housing;
• wherein, when the amount of the toner contained in the developing unit housing is not greater than the predetermined amount, the controller is configured to execute the supplying process every time the usage amount of the toner becomes equal to or greater than a supplying threshold that is less than the detecting thresold.