Image forming apparatus

An image forming apparatus comprising:

• a first image bearing member for bearing a toner image;
• a second image bearing member for bearing a toner image;
• a transfer belt having electroconductivity;
• a first transfer member provided correspondingly to said first image bearing member via said transfer belt;
• a second transfer member provided correspondingly to said second image bearing member via said transfer belt;
• a high-voltage power source for applying a voltage to said first and second transfer members;
• and
• a controller,
• wherein after an image is continuously formed on a plurality of transfer materials by applying, to said first transfer member, a voltage of a predetermined polarity from said high-voltage power source in a state in which said first transfer member contacts said transfer belt and in which said second transfer member is spaced from said transfer belt, said controller executes an adjusting operation in which a voltage of a polarity identical to the predetermined polarity is applied from said high-voltage power source to said second transfer member in a state in which said first transfer member is spaced from said transfer belt and in which said second transfer member contacts said transfer belt.