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 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.

In order to miniaturize an image forming system, the present invention provides an image forming system which is provided with a sheet feed apparatus including a transport roller pair capable of transporting a sheet in a sheet transport direction S, and an image forming apparatus including an image forming section capable of forming an image on the sheet acquired from the sheet feed apparatus, including a switch member disposed on the downstream side of the transport roller pair in the sheet transport direction to be switched between a first position for guiding the sheet transported by the transport roller pair to the image forming apparatus, and a second position for guiding the sheet transported by the transport roller pair downward, and a storage tray disposed below the switch member predetermined space apart to be able to store the sheet guided to below the switch member positioned in the second position.

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 feeding apparatus capable of switching between a first feeding mode and a second feeding mode, in which in the first feeding mode, when a first detection section positioned downstream of a feeding roller in a medium feeding direction detects passage of a trailing end of a preceding medium in a feeding standby state in which driving of the feeding roller that feeds the medium is stopped, starting the driving of the feeding roller to perform feeding of a succeeding medium, and in the second feeding mode, when a second detection section positioned downstream of the first detection section in the medium feeding direction detects the passage of the trailing end of the preceding medium in the feeding standby state, starting the driving of the feeding roller to perform the feeding of the succeeding medium.

A sheet conveying apparatus includes a tray having a plurality of sheets, a feeder to successively convey sheets stacked on the tray, a controller, and a double-feed sensor to detect double feed when the feeder conveys a plurality of sheets in an overlapping manner. When a double-feed length, which corresponds to a length, in a conveyance direction of the sheet, of a region in which the double feed has been detected by the double-feed sensor, is larger than a predetermined distance, the controller determines that the double feed has occurred. When the double-feed length is smaller than the predetermined distance and a sheet size is smaller than a predetermined size, the controller determines that the double feed has occurred. When the double-feed length is smaller than the predetermined distance and the sheet size is larger than the predetermined size, the controller determines that the double feed has not occurred.

A medium feeding device includes: a placement unit on which a medium is placed; a pair of edge guides that is provided at the placement unit such that the edge guides are movable in a medium width direction to guide edges of the medium in the medium width direction that is a direction intersecting a medium feeding direction; feeding rollers that feed the medium placed on the placement unit; a path state detection section that detects a detection value in accordance with a state of the medium feeding path; a guide position detection section that detects positions of the edge guides; and a control section that determines whether or not the detection value detected by the path state detection section has exceeded a threshold value.

Provided is an inspection device that performs inspection using ultrasonic waves transmitted on the basis of a burst signal including a plurality of pulses, the inspection device includes: a decider that decides the number of pulses included in the burst signal, or a burst cycle of the burst signal, on the basis of an atmospheric pressure at an installation position of the inspection device; a generator that repeatedly generates the burst signal including the decided number of pulses, or the burst signal having the decided burst cycle; a transmitter that transmits ultrasonic waves on the basis of the burst signal repeatedly generated; and a receiver that receives ultrasonic waves.

A conveyor conveys a sheet along a conveyance path provided with an ultrasonic sensor, and includes: an updating member that successively updates a parameter indicating aged deterioration of the conveyor; a searcher that searches a look-up table storing pieces of noise data of noises predicted to be superimposed on a detection signal of the ultrasonic sensor in accordance with a degree of the aged deterioration, and obtains a piece of noise data corresponding to a current parameter value of the conveyor; and a signal processor that uses, for signal processing, a remaining portion of the detection signal of the ultrasonic sensor excluding a portion corresponding to the piece of noise data obtained by the searcher.

A transport apparatus includes a speaker and a mike disposed at respective positions between which a transport path of a medium is interposed, where the speaker and the mike face each other, a drive circuit that outputs a drive signal to the speaker, an amplifier circuit formed by coupling a plurality of amplifiers in series, where the amplifier circuit amplifies and outputs an output signal of the mike, a processor to which the output signal of the amplifier circuit is input, an attenuation circuit disposed in a stage preceding a predetermined amplifier, where the attenuation circuit attenuates an input signal and outputs the input signal to the predetermined amplifier, and a switch that switches an attenuation factor by the attenuation circuit.