Medium conveying apparatus to detect predetermined medium based on lift of medium

A medium conveying method comprising:

• feeding a medium by a pick roller;
• detecting a lift of the medium by a first lift sensor located on a downstream side of an upstream edge of a nip width of the pick roller and on one side of the pick roller toward a conveying direction of the medium;
• detecting a lift of the medium by a second lift sensor placed on the downstream side of the upstream edge of the nip width of the pick roller and on another side of the pick roller toward the conveying direction;
• detecting the medium by a first detection sensor placed on a same side as the first lift sensor with respect to the pick roller;
• detecting the medium by a second detection sensor placed on a same side as the second lift sensor with respect to the pick roller;
• determining that the medium is a predetermined medium when a height of a lift of the medium detected by the first lift sensor or second lift sensor is greater than or equal to a threshold value;
• and
• executing abnormality control when the medium is determined to be the predetermined medium, wherein, in the determination, the threshold value for the first lift sensor is increased when it is detected by the first and second detection sensors that the first detection sensor side of the medium precedes the second detection sensor side.

A computer-readable, non-transitory storage medium storing a computer program for a medium conveying apparatus including a pick roller feeding a medium, a first lift sensor located on a downstream side of an upstream edge of a nip width of the pick roller and on one side of the pick roller toward a conveying direction of the medium, to detect a lift of the medium, a second lift sensor located on the downstream side of the upstream edge of the nip width of the pick roller and on another side of the pick roller toward the conveying direction, to detect a lift of the medium, a first detection sensor located on a same side as the first lift sensor with respect to the pick roller, to detect the medium;

• and a second detection sensor located on a same side as the second lift sensor with respect to the pick roller, to detect the medium, the computer program causing the medium conveying apparatus to execute a process, the process comprising:
• determining that the medium is a predetermined medium when a height of a lift of the medium detected by the first lift sensor or second lift sensor is greater than or equal to a threshold value;
• and
• executing abnormality control when the medium is determined to be the predetermined medium, wherein, in the determination, the threshold value for the first lift sensor is increased when it is detected by the first and second detection sensors that the first detection sensor side of the medium precedes the second detection sensor side.