Patent ID: 7441769

Claim:
A detector for detecting a size of a recording medium in a device, comprising: a tray that stores the recording medium to be fed to the device, the tray being detachably attached to the device, including a first regulating member capable of sliding in a width direction of the recording medium according to the size of the recording medium, and a second regulating member capable of sliding in a feed direction of the recording medium according to the size of the recording medium; a first movable member that engages with the first regulating member, rotates around a pivot in conjunction with the first regulating member, and includes a plurality of first convex members on a peripheral edge thereof; a second movable member, overlapped by the first movable member, that engages with the second regulating member, rotates around the pivot in conjunction with the second regulating member, and includes a plurality of second convex members on a peripheral edge thereof, the first and second convex members are formed equidistant from the pivot, wherein the first convex members and the second convex members form a plurality of combined convex members; and a plurality of switches that are selectively pressed by the plurality of combined convex members when the tray is attached to the device.