Patent ID: 7845753

Claim:
An image forming device which prints an image on a recording sheet by performing a reciprocating movement of a print head in a main scanning direction while transporting the recording sheet intermittently in a transporting direction, comprising: a filler sensor disposed at an upstream position of the print head in the transporting direction to detect that the recording sheet has passed through a first position; a measurement-value computing unit configured to compute a measurement value indicating a distance from a second position of a sensor, disposed near the print head, to a rear-end position of the recording sheet in the transporting direction, by using a computed distance between the second position and the first position; a theoretical-value computing unit configured to compute a theoretical value indicating the distance from the second position to the rear-end position of the recording sheet, by using a quantity of transporting of the recording sheet; and a selecting unit configured to select one of the measurement value and the theoretical value based on a result of comparison between the measurement value and the theoretical value, so that the selected value is used as a value that indicates the rear-end position of the recording sheet.