Document storage trays are disclosed that may be stacked in at least two different configurations including a \u201cnesting\u201d stack where an upper tray fits within the storage area of a lower tray and, in turn, is also able to receive a tray within its own storage area so that multiple trays can be stacked nested together. An estimated duration of each job is predicted as a running average of the measured durations of completed instances of the job executed previously. Program executing means transmits its authenticator only during the authenticator accepting period. 25% at wavelengths from 400 nm to 780 nm, where A is an average value of initial light transmittance of the polarizing plate at wavelengths from 400 nm to 780 nm, and B is an average value of light transmittance of the polarizing plate at wavelengths from 400 nm to 780 nm measured after the polarizing plate has been dipped in water of 25\xb0 C.