An example print medium supplying apparatus includes a print medium transporting device to pick up a print medium loaded in a loading portion and transport the picked-up print medium, a print medium alignment portion to align a leading end of the transported print medium, a first sensor to sense the print medium that passes through a feed roller of the print medium transporting device, and a processor to, based on a measured value with respect to the print medium sensed by the first sensor and a multi-feeding determination reference value corresponding to a sheet of the print medium, detect multi-feeding of the print medium and process the detected multi-feeding by controlling the print medium transporting device and the print medium alignment portion.

A medium conveying apparatus includes a conveying roller to convey a rectangular medium, and a processor to generate an input image acquired by imaging the conveyed medium, detect an overlap of the conveyed medium, detect an object area from the input image, determine whether an outer shape of the object area is rectangular, determine whether a multi-feed of the medium has occurred based on whether the overlap of the medium has been detected and whether the outer shape of the object area is rectangular, and execute an abnormality processing when it is determined that the multi-feed of the medium has occurred.

An ultrasonic device has a substrate in which ultrasonic elements transmitting an ultrasonic wave in a first direction are arrayed. A reverberation reduction film which reduces reverberant vibration of the substrate is arranged on a side of the first direction in the ultrasonic element. In the reverberation reduction film, a groove is arranged between the ultrasonic elements next to each other.

A method of measuring properties of a moving cellulose, paper or board sheet. A first parameter of a first resonance caused by the moving sheet in a frequency range 1 GHz to 25 GHz of electromagnetic radiation is measured. A second parameter of an electromagnetic signal transmitted between at least a pair of transceiver parts of a transceiver sensor located on opposite sides of the moving sheet through the moving sheet is measured in a frequency range 25 GHz to 1000 GHz. A minimum difference between the frequency ranges related to the first parameter and the second parameter being at least 5 GHz. Both the dry stuff content and the weight of water per unit of area are determined on the basis of the first parameter, the second parameter and available information related to a distance travelled by the electromagnetic signal.

A medium feeding device is provided with a feeding section for feeding a medium and sensors for detecting the medium. The feeding section includes a feed roller and a separation roller, the sensors form a sensor line in which the plurality of sensors is aligned in a feeding direction of the medium to be fed, the two sensor lines are arranged in such a manner that the sensors overlap with each other in a width direction of the medium to be fed, and the sensor lines are so configured as to extend, in the feeding direction, from an upstream region upstream of a nip point where the feed roller and the separation roller make contact with each other, a nip region including the nip point, and to a downstream region downstream of the nip point.

An ultrasonic sensor includes a first base facing a conveying surface, a transmission section on a first axis tilted relative to the conveying surface and at a far side of the first base for transmitting an ultrasonic wave toward the first axis, and a reception section on the first axis and at a far side of the conveying surface for receiving the ultrasonic wave. The transmission section has a plurality of transmission elements for transmitting the ultrasonic wave arranged to cross the first axis. The first base has a first aperture through which the ultrasonic wave transmitted from the transmission section along the first axis passes. An area of the first aperture is smaller than an area of an ultrasonic wave transmission surface of the transmission section. The transmission section delays driving the transmission elements to converge the ultrasonic wave transmitted from the transmission section toward the first aperture.

An image reading apparatus includes a feed roller configured to feed paper toward a reading section, and a medium detection section provided along a transport path between the feed roller and the reading section and configured to include a transmitting portion configured to output an output value equivalent to a magnitude of an ultrasonic wave, and determines whether the transport of the paper is to be continued or to be brought to a halt on the basis of a lower limit value and an upper limit value for the output value, which are set in accordance with the kind of the paper. Further, in a case where the output value satisfies a first condition, a transport of the medium is continued, and in a case where the output value satisfies a condition different from the first condition, the transport of the medium is brought to a halt.

A multi-feed detection device includes a transmission circuit substrate to which an ultrasonic transmitter transmitting an ultrasonic wave is installed, and an ultrasonic receiver receiving the ultrasonic wave. The ultrasonic transmitter has arrayed ultrasonic transmission elements and transmits ultrasonic waves with different phases from the ultrasonic transmission elements to transmit the ultrasonic waves in a direction diagonally intersecting a thickness direction of the transmission circuit substrate.

A multi-feed detection device includes a transmission circuit substrate on which an ultrasonic transmitter transmitting an ultrasonic wave is installed, and an ultrasonic receiver receiving the ultrasonic wave. The ultrasonic transmitter transmits the ultrasonic wave in a direction intersecting a thickness direction of the transmission circuit substrate and at least one of the ultrasonic transmitter and the ultrasonic receiver has a plurality of ultrasonic elements.

A medium conveyance apparatus includes a drive signal output circuit to output a drive signal at a predetermined timing, a first sound wave emitter to output a sound wave based on the drive signal outputted at the predetermined timing, a first sound wave receiver to output a first sound wave signal corresponding to the received sound wave, a second sound wave emitter to output a sound wave based on the drive signal outputted at the predetermined timing, a second sound wave receiver to output a second sound wave signal corresponding to the received sound wave, a processor to determine a state of the medium based on the first sound wave signal and the second sound wave signal, and an output circuit to output the first sound wave signal and the second sound wave signal to the processor at timings different from each other.