Patent ID: 7828291

Claim:
A conveying mechanism comprising: a pair of conveying rollers which conveys a paper-like medium; a conveying guide which guides the paper-like medium to the conveying rollers; and a conveying housing which defines a conveying path along which the paper-medium is conveyed, a first bulging space and a second bulging space being provided on a downstream side and an upstream side, respectively, of the conveying path, the second bulging space having a length L 1 along the conveying path, the conveying path between the first and second bunging spaces being defined to have a length L 2 , the lengths L 1 and L 2 satisfying a relationship expressed by Formula 1, L 2 = 2 ⁢ ⁢ m 2 ⁢ ⁢ n - 1 ⁢ L 1 ⁢ ( n = 1 , 2 , … ⁢ ) ⁢ ( m = 1 , 2 , … ⁢ ) ( 1 ) f = ( 2 ⁢ ⁢ n - 1 ) ⁢ c 4 ⁢ ⁢ L 1 ⁢ ⁢ ( n = 1 , 2 , … ⁢ ) ( 2 ) wherein in Formulas 1 and 2, c denotes sound velocity, and f denotes a frequency of possible noise propagating through the conveying path and corresponds to a central frequency of a frequency band of noise to be attenuated in the conveying housing.