Abstract: Timing marks are printed at the left and right of a data mark of a two-dimensional dot code. Whether or not the data mark exists is determined based on the position on the line connecting the centers of the timing marks at both ends at the left and right of the data mark.

Abstract: An ultrasonic wave receiver receives an ultrasonic wave outputted by an ultrasonic wave oscillator, and outputs a receiving signal. A level determining unit makes a determination as to the presence or absence of a sheet of paper based upon a level of the receiving signal. A CPU is informed of this determining signal through a processing unit. An oscillation peak detector detects a peak value of a transmission signal used for controlling an ultrasonic wave transmitter, which is transmitted from an oscillation amplifier. A receiving peak detector detects a peak value of the receiving signal received by the ultrasonic transmitter. The phase difference of the two signals is detected based upon the difference in count values of a loop counter between the timing in which the peak value of the transmission signal is detected and the timing in which the peak value of the receiving signal is detected.

Abstract: An ultrasonic wave that is transmitted from an ultrasonic-wave transmitter 1 is received by an ultrasonic-wave receiver 2, through a sheet 4. A reception signal is input to an extracting unit 19. The extracting unit compares its phase with a phase of a reference signal output from a reference-signal reproduction unit 18. It converts a phase difference therebetween into a signal having a level corresponding to the phase difference. The signal having a level corresponding to the phase difference is compared with a threshold value set in a threshold-value setter 20, by a comparator 21. When one sheet 4 is fed, the comparator 21 produces a signal of high level. When a doubles feeding occurs, it produces a signal of low level.

Abstract: The information processing device includes a first device (31) supplied with power and a second device (32) supplied with power from the first device (31) when connected to the first device (31). The information processing device includes a detection portion (121-1, 121-n, 221-1, 221-n) detecting the attachment/detachment of the second device (32) and a supply portion (121-2, 221-2) supplying power to the second device (32), and the first device (31) includes a control portion (151) controlling the supply of the power by the supply portion (121-2, 221-2) according to the result of detection by the detection portion (121-1, 121-n, 221-1, 221-n). As the supply of the power by the supply portion (121-2, 221-2) is controlled according to the result of the detection by the detection portion (121-1, 121-n, 221-1, 221-n), the electric shock on an internal circuit of the second device (32) at the time of attachment/detachment of second device (32) can be prevented.