A printing apparatus that performs image-printing by thermally transferring inks of multiple colors applied to an ink ribbon onto a printing medium in a superimposed manner, the printing apparatus comprising: an image-printing unit (115, 207) configured to transfer at least one color of the inks of multiple colors applied to the ink ribbon onto a printing medium; an interface configured to supply power from an outside to the printing apparatus; a battery; a conveyance unit (124, 125, 216) configured to convey a printing medium to an image-printing start position, at which the image-printing unit (115, 207) starts transferring at least one color of the inks of multiple colors onto the printing medium, using power from the battery or the interface; and a control unit configured to perform, before conveyance of a printing medium is started by the conveyance unit (124, 125, 216), a first determination to determine whether a remaining battery level of the battery is equal to or more than a first threshold, characterized in that, in a case where the remaining battery level is equal to or more than the first threshold as a result of the first determination, cause the conveyance unit (124, 125, 216) to convey the printing medium by power from the battery, in a case where the remaining battery level is less than the first threshold as a result of the first determination and the printing apparatus is supplied with power from the interface, charge the battery with power from the interface, cause the conveyance unit (124, 125, 216) to convey the printing medium, and perform, after the printing medium reaches a predetermined position, a second determination to determine whether a remaining battery level of the battery is equal to or more than a second threshold, and in a case where the remaining battery level is equal to or more than the second threshold as a result of the second determination, start image-printing processing to cause the image-printing unit (115, 207) to transfer the inks of multiple colors onto the printing medium. an image-printing unit (115, 207) configured to transfer at least one color of the inks of multiple colors applied to the ink ribbon onto a printing medium; an interface configured to supply power from an outside to the printing apparatus; a battery; a conveyance unit (124, 125, 216) configured to convey a printing medium to an image-printing start position, at which the image-printing unit (115, 207) starts transferring at least one color of the inks of multiple colors onto the printing medium, using power from the battery or the interface; and a control unit configured to perform, before conveyance of a printing medium is started by the conveyance unit (124, 125, 216), a first determination to determine whether a remaining battery level of the battery is equal to or more than a first threshold, characterized in that, in a case where the remaining battery level is equal to or more than the first threshold as a result of the first determination, cause the conveyance unit (124, 125, 216) to convey the printing medium by power from the battery, in a case where the remaining battery level is less than the first threshold as a result of the first determination and the printing apparatus is supplied with power from the interface, charge the battery with power from the interface, cause the conveyance unit (124, 125, 216) to convey the printing medium, and perform, after the printing medium reaches a predetermined position, a second determination to determine whether a remaining battery level of the battery is equal to or more than a second threshold, and in a case where the remaining battery level is equal to or more than the second threshold as a result of the second determination, start image-printing processing to cause the image-printing unit (115, 207) to transfer the inks of multiple colors onto the printing medium. perform, before conveyance of a printing medium is started by the conveyance unit (124, 125, 216), a first determination to determine whether a remaining battery level of the battery is equal to or more than a first threshold, characterized in that, in a case where the remaining battery level is equal to or more than the first threshold as a result of the first determination, cause the conveyance unit (124, 125, 216) to convey the printing medium by power from the battery, in a case where the remaining battery level is less than the first threshold as a result of the first determination and the printing apparatus is supplied with power from the interface, charge the battery with power from the interface, cause the conveyance unit (124, 125, 216) to convey the printing medium, and perform, after the printing medium reaches a predetermined position, a second determination to determine whether a remaining battery level of the battery is equal to or more than a second threshold, and in a case where the remaining battery level is equal to or more than the second threshold as a result of the second determination, start image-printing processing to cause the image-printing unit (115, 207) to transfer the inks of multiple colors onto the printing medium.