Abstract: A method and apparatus are provided for aligning the printer carriage of an inkjet printer with a service station of the printer where for example capping, wiping or spitting of inkjet cartridges held by the printer carriage can be performed. The method utilizes an optical sensor mounted on the printer carriage to scan a reference mark within the service area. Preferably the reference mark exhibits a change in reflectance in the scanning direction of the printer carriage and is mounted on a service station carriage which also holds removable service modules. An embodiment employs an iterative method in which calibration steps are interspersed by capping operations so as to ensure accurate alignment is achieved.