An image forming apparatus comprising a transfer device, an image carrier that carriers a toner image and a fixing device, the transfer device including: a conveyance belt being in contact with the image carrier and configured to convey a sheet via a contact position with the image carrier; characterized by a transfer roller to which a voltage having a polarity opposite to a charging polarity of toner that forms the toner image is applied, the transfer roller being configured to transfer the toner image carried by the image carrier onto the sheet at the contact position; a stretch roller to which the voltage having the polarity opposite to the charging polarity of the toner is applied, the stretch roller being configured to stretch the conveyance belt at a separation position in which the sheet is separated from the conveyance belt, the separation position being downstream of the contact position in a conveyance direction in which the sheet is conveyed by the conveyance belt; and a guide member to which the voltage having the polarity opposite to the charging polarity of the toner is applied, the guide member for guiding the sheet being formed of a conductive member and provided at a position opposed to the sheet being conveyed from the stretch roller to the fixing device that is configured to fix, to the sheet, the toner image that has been transferred to the sheet by the transfer roller, wherein the image forming apparatus is configured such that the voltage having the polarity opposite to the charging polarity of the toner is applied to the transfer roller, the stretch roller and the guide member during a period from when a front end portion of the sheet in the conveyance direction arrives at the contact position to when a rear end portion of the sheet in the conveyance direction separates from the separation position. a conveyance belt being in contact with the image carrier and configured to convey a sheet via a contact position with the image carrier; characterized by a transfer roller to which a voltage having a polarity opposite to a charging polarity of toner that forms the toner image is applied, the transfer roller being configured to transfer the toner image carried by the image carrier onto the sheet at the contact position; a stretch roller to which the voltage having the polarity opposite to the charging polarity of the toner is applied, the stretch roller being configured to stretch the conveyance belt at a separation position in which the sheet is separated from the conveyance belt, the separation position being downstream of the contact position in a conveyance direction in which the sheet is conveyed by the conveyance belt; and a guide member to which the voltage having the polarity opposite to the charging polarity of the toner is applied, the guide member for guiding the sheet being formed of a conductive member and provided at a position opposed to the sheet being conveyed from the stretch roller to the fixing device that is configured to fix, to the sheet, the toner image that has been transferred to the sheet by the transfer roller, wherein the image forming apparatus is configured such that the voltage having the polarity opposite to the charging polarity of the toner is applied to the transfer roller, the stretch roller and the guide member during a period from when a front end portion of the sheet in the conveyance direction arrives at the contact position to when a rear end portion of the sheet in the conveyance direction separates from the separation position.