Image forming apparatus

An image forming apparatus comprising:

• an image carrier that holds, while rotating, an electrostatic latent image formed through charging and light exposure steps, which are included in a toner-image forming process, and a toner image formed through a development step, which is included in the toner-image forming process, the development step using a toner contained in a developer, which contains the toner and a carrier;
• a charger that is disposed at a charging position facing the image carrier and that charges the image carrier as a result of a charging bias being applied to the charger;
• an exposure unit that radiates exposure light carrying image information onto the image carrier in such a manner as to form an electrostatic latent image onto the image carrier;
• a developing unit that is disposed at a developing position facing the image carrier and that develops the electrostatic latent image on the image carrier with the toner contained in the developer as a result of a developing bias being applied to the developing unit;
• a transfer unit that is disposed at a transfer position facing the image carrier and that nips a sheet, which is transported, between the transfer unit and the image carrier and transfers a toner image on the image carrier onto the sheet as a result of a transfer bias being applied to the transfer unit;
• a fixing unit that fixes a toner image on a sheet that has been further transported after the toner image has been transferred to the sheet onto the sheet;
• a charging-bias power supply that applies the charging bias to the charger in such a manner that voltage is capable of being freely adjusted;
• a transfer-bias power supply that applies a reverse transfer bias having a polarity opposite to a polarity of the transfer bias to the transfer unit in a switchable manner;
• and
• a controller that causes the charging-bias power supply to apply the charging bias, which monotonically changes with time, to the charger over a predetermined transition period during a period when the toner-image forming process is not performed, causes the transfer-bias power supply to apply the reverse transfer bias to the transfer unit over a predetermined reverse transfer period within a transit period in which a transient charged region of the image carrier that has passed through the charging position within the transition period passes through the transfer position, and causes the exposure unit to radiate the exposure light onto a reverse transfer region of the image carrier before the reverse transfer region that has passed through the transfer position within the reverse transfer period reaches the developing position.