Medium transport apparatus, image forming apparatus and medium transport method

An image forming apparatus comprising:

• a transport unit that transports a recording medium continuing in a direction, in the direction where the recording medium continues;
• an image forming unit that forms an image on the recording medium transported by the transport unit;
• a detection unit that detects a mark formed on the recording medium transported by the transport unit, by using a detection effective range in a direction crossing a transport direction of the recording medium;
• a positional relationship identification unit that identifies a relative positional relationship between the detection unit and the mark in the direction crossing the transport direction, from a detection result obtained by the detection unit;
• and
• a move unit that moves the detection unit in the direction crossing the transport direction, on the basis of the relative positional relationship identified by the positional relationship identification unit,
• wherein the recording medium is a continuous paper having portions defining feed holes regularly formed in the direction,
• the image forming apparatus further comprises:
• an identification unit that identifies, from the detection result from the detection unit, a position of the portions defining the feed holes in width directions of the continuous paper from an end part of the continuous paper;
• and
• a determination unit that determines a destination position to which the detection unit is to be moved, on the basis of an identification result obtained by the identification unit, and
• the move unit moves the detection unit to the destination position determined by the determination unit before moving the detection unit on the basis of the relative positional relationship identified by the positional relationship identification unit.

A medium transport method comprising:

• transporting a recording medium continuing in a direction, in the direction where the recording medium continues;
• detecting a mark formed on the recording medium thus transported, by using a detection effective range of a detection unit, the detection effective range in a direction crossing a transport direction of the recording medium;
• identifying a relative positional relationship between the detection unit and the mark in the direction crossing the transport direction, from a detection result obtained by the detection unit;
• and
• moving the detection unit in the direction crossing the transport direction, on the basis of the relative positional relationship,
• wherein the recording medium is a continuous paper having portions defining feed holes regularly formed in the direction,
• the method further comprises:
• an identifying step for identifying, from the detection result from the detection unit, a position of the portions defining the feed holes in width directions of the continuous paper from an end part of the continuous paper;
• and
• a determination step for determining a destination position to which the detection unit is to be moved, on the basis of an identification result obtained by the identifying step, and
• moving the detection unit to the destination position determined by the determination step before moving the detection unit on the basis of the relative positional relationship identified by the positional relationship identification unit.

A medium transport apparatus comprising:

• a transport unit that transports a recording medium continuing in a direction, in the direction where the recording medium continues;
• a detection unit that detects a mark formed on the recording medium transported by the transport unit, by using a detection effective range in a direction crossing a transport direction of the recording medium;
• a positional relationship identification unit that identifies a relative positional relationship between the detection unit and the mark in the direction crossing the transport direction, from a detection result obtained by the detection unit;
• and
• a move unit that moves the detection unit in the direction crossing the transport direction, on the basis of the relative positional relationship identified by the positional relationship identification unit,
• wherein the positional relationship identification unit identifies, as the relative positional relationship between the detection unit and the mark, a deviation amount between a center position of the detection effective range of the dectection unit in the direction crossing the transport direction and a center position of the mark in the direction crossing the transport direction,
• the move unit moves the detection unit on the basis of the deviation amount identified by the positional relationship identification unit, so as to align the center position of the detection effective range of the detection unit in the fast scan direction with the center position of the mark in the fast scan direction,
• the positional relationship identification unit compares a move amount of the detection unit identified from the deviation amount with a predetermined maximum value stored in a memory unit, and
• the move unit replaces the move amount of the detection unit with the predetermined maximum value when the positional relationship identification unit determines that the move amount of the detection unit is larger than the predetermined maximum value.