Patent ID: 7458655

Claim:
A printing apparatus for printing on a printing medium by using a printing head for applying ink on the printing medium, said apparatus comprising: pattern printing control means for printing a predetermined pattern on the printing medium; an optical sensor located in the vicinity of said printing head in order to read the predetermined pattern printed on the printing medium; positioning means for positioning the printing medium to a printing position by said printing head and a reading position by said optical sensor; and adjustment value setting means for setting an adjustment value for adjusting an applying position of the ink to be applied from said printing head based on a result of the reading by said optical sensor, wherein said positioning means includes a transfer mechanism for transferring the printing medium along a transfer path, wherein said transfer mechanism comprises a first roller pair located on an upstream side and a second roller pair located on a downstream side relative to said printing head in a transfer direction of the printing medium along the transfer path, wherein pressure in a nipping portion of said first roller pair is greater than pressure in a nipping portion of said second roller pair, wherein a first rib group of a plurality of ribs provided in the transfer path at intervals in a direction intersecting the transfer direction and a second rib group of the plurality of ribs provided in the transfer path at intervals in the direction intersecting the transfer direction are located between said first roller pair and said second roller pair in the transfer direction, wherein said first rib group is located on the upstream side and said second rib group is located on the downstream side relative to the printing head in the transfer direction, and wherein said optical sensor is located above a location between said first rib group and said second rib group in the transfer direction or a location between said first rib group and said first roller pair in the transfer direction.