Patent ID: 7621614

Claim:
A printing apparatus, comprising: a transport unit that transports a medium in a transporting direction; a head that performs recording on a medium using ink and that moves in a moving direction; a first sensor that moves in said moving direction together with said head and that detects an edge of said medium; and a second sensor that moves in said moving direction together with said head and that detects a pattern formed on said medium by said head; wherein: said first sensor is provided further upstream with regard to said transporting direction than said second sensor, said head has a plurality of colored-liquid nozzles that eject a colored liquid and a plurality of colorless-liquid nozzles that eject a colorless liquid, each of said plurality of colored-liquid nozzles respectively forms a colored block pattern on said medium, a plurality of the colored block patterns are formed on said medium lined up in a straight line in said moving direction and leaving no space between the colored block patterns adjacent to one another, said plurality of the colored block patterns constituting a group of tested colored block patterns to be subjected to testing, said second sensor detects said tested colored block patterns that are lined up in said moving direction while moving once in said moving direction in order to test whether there is a colored-liquid nozzle that has not ejected said colored liquid, said group of tested colored block patterns is surrounded by a non-tested pattern that is not subjected to testing by said second sensor, each of said plurality of colorless-liquid nozzles respectively forms a colorless block pattern on said medium, a plurality of the colorless block patterns are formed on said medium lined up in a straight line in said moving direction and leaving a space between the colorless block patterns adjacent to one another, said plurality of colored-liquid nozzles apply said colored liquid onto said plurality of the colorless block patterns, and said second sensor detects, while moving once in said moving direction, a degree of smearing of said colored liquid at a position where said colorless block pattern is to be formed in order to detect whether there is a colorless-liquid nozzle that has not ejected said colorless liquid.