Patent attributes
A flattening device includes: a holder configured to support the following components; at least one flattening roller set, including a first flattening roller and a second flattening roller arranged oppositely at two sides of a sheet medium conveying path; and a power mechanism configured to drive the first and second flattening rollers to rotate. A surface of the first flattening roller is distributed with n arc-shaped grooves arranged in parallel with an axis direction of the first flattening roller, wherein n is a natural number greater than or equal to 1; and a surface of the second flattening roller is provided with at least one arc-shaped protruding portion in rolling engagement with the arc-shaped grooves of the first flattening roller; and wherein, the first flattening roller and the second flattening roller are in rolling engagement to form a conveying passage for the sheet medium.