A light emitting diode structure includes a plurality of devices arranged side by side on a support layer. First and second electrical contacts are mounted in the carriage toward an axis of the trunnion. The openings of each pan are located at positions different from the openings of the other pans in such a manner that the openings of each pair of adjacent pans be vertically out of line. First and second attractive portions of the magnet holder are formed so as to be engaged with a corner formed by an upper surface and a front surface of one of the endpieces. Shifting roller is provided opposite to forwarding roller to shift sheets back to a direction which is the reverse of conveying direction if the sheets are overlapped. The transmission mechanism is disposed at one end of the pivot.