A printer, comprising: a print head configured to print on recording paper; a first roller; a cutter unit configured to cut the recording paper; and a presenter unit connected to the cutter unit and having a discharge slot from which the recording paper is discharged, wherein the recording paper on which the print head has printed enters the presenter unit through the cutter unit, and comes out from the discharge slot, and wherein the presenter unit includes: a second roller configured to convey the recording paper; a flapper disposed along a transportation path of the recording paper between the second roller and the cutter unit and configured to be flipped open to outside the presenter unit to expose the transportation path; and a recording paper sensor disposed between the second roller and the discharge slot, wherein detection of the recording paper by the recording paper sensor causes the second roller to stop rotating, and causes the flapper to be flipped open to outside the presenter unit; the printer further comprising a recording paper transport guide disposed along the transportation path of the recording paper between the second roller and the cutter unit, wherein upon the flapper being flipped open to outside the presenter unit, the recording paper transport guide moves toward outside the presenter unit, so that the recording paper transport guide guides the recording paper to outside the presenter unit. a print head configured to print on recording paper; a first roller; a cutter unit configured to cut the recording paper; and a presenter unit connected to the cutter unit and having a discharge slot from which the recording paper is discharged, wherein the recording paper on which the print head has printed enters the presenter unit through the cutter unit, and comes out from the discharge slot, and wherein the presenter unit includes: a second roller configured to convey the recording paper; a flapper disposed along a transportation path of the recording paper between the second roller and the cutter unit and configured to be flipped open to outside the presenter unit to expose the transportation path; and a recording paper sensor disposed between the second roller and the discharge slot, a second roller configured to convey the recording paper; a flapper disposed along a transportation path of the recording paper between the second roller and the cutter unit and configured to be flipped open to outside the presenter unit to expose the transportation path; and a recording paper sensor disposed between the second roller and the discharge slot, wherein detection of the recording paper by the recording paper sensor causes the second roller to stop rotating, and causes the flapper to be flipped open to outside the presenter unit; the printer further comprising a recording paper transport guide disposed along the transportation path of the recording paper between the second roller and the cutter unit, wherein upon the flapper being flipped open to outside the presenter unit, the recording paper transport guide moves toward outside the presenter unit, so that the recording paper transport guide guides the recording paper to outside the presenter unit.