Sheet detection device and detection method thereof

A sheet detection device, incorporated with a paper tray, the paper tray comprising a paper guide, and the sheet detection device comprising:

• a magnetic element, disposed on the paper guide;
• a first magnetic sensing element, disposed on the paper tray and configured to generate a first voltage signal corresponding to the magnetic element;
• a second magnetic sensing element, disposed on the paper tray, arranged spacedly with the first magnetic sensing element, and configured to generate a second voltage signal corresponding to the magnetic element;
• a processing element, electrically connected with the first magnetic sensing element and the second magnetic sensing element, and configured to receive the first voltage signal and the second voltage signal;
• and
• a third magnetic sensing element, disposed on the paper tray, arranged spacedly with the second magnetic sensing element, and the second magnetic sensing element located between the first magnetic sensing element and the third magnetic sensing element;
• and
• wherein a first spacing between the first magnetic sensing element and the second magnetic sensing element is different from a second spacing between the second magnetic sensing element and the third magnetic sensing element,
• wherein the processing element is configured to determine a first relative position of the magnetic element relative to the first magnetic sensing element according to the first voltage signal, and determine a second relative position of the magnetic element relative to the second magnetic sensing element according to the second voltage signal, and
• the processing element is configured to determine a stopping position of the magnetic element according to the first relative position and the second relative position, and determine a sheet size of a paper abutted by the paper guide according to the stopping position.