A transmitter transmits ultrasonic wave of a predetermined volume. A reflected ultrasonic wave receiver receives reflected ultrasonic wave, transmitted from the transmitter and reflected by a sheet. A permeated ultrasonic wave receiver receives permeated ultrasonic wave, transmitted by the transmitter and permeated through the sheet. A volume detector detects reflected volume of the reflected ultrasonic wave, and permeated volume of the permeated ultrasonic wave. The decider identifies a thickness of the sheet being transported by a transport device, and decides whether multifeed of the sheets is occurring, on a basis of a comparison result between the detected reflected volume and a reference reflected volume, and a comparison result between the detected permeated volume and a reference permeated volume.

A diagnostic device includes a reception unit and a determination unit. The reception unit is configured to receive context information and sensing information. The context information corresponds to a certain operation of a target item that constitutes a target device. The context information is a piece of a plurality of pieces of context information each describing an operation of the target item determined depending on a type of operation of the target device. The sensing information is on a physical quantity that varies in accordance with the operation of the target item. The determination unit is configured to determine a state of the target item based on the sensing information detected while the target item is performing the certain operation, and based on a model corresponding to the received context information. The model is a model of one or more models respectively defined for one or more pieces of the context information.

A sheet conveyance apparatus including a transmission unit that transmits an ultrasonic wave toward a sheet and a reception unit that receives the ultrasonic wave includes a change unit that changes a distance of a conveyance path of the sheet according to sheet information about the sheet to be conveyed.

A recording material determination apparatus includes a transmission unit, a reception unit, and a determination unit. The transmission unit transmits an ultrasonic wave to a recording material. The reception unit vibrates when the reception unit receives the ultrasonic wave having been transmitted from the transmission unit and having passed through the recording material, and outputs a signal corresponding to a vibration state. The determination unit determines a basis weight of the recording material in accordance with the signal output from the reception unit. A resonance frequency of the reception unit differs from a resonance frequency of the transmission unit, and the reception unit is capable of receiving a sound wave in an ultrasonic range and a sound wave in an audible range.

An image forming apparatus includes plural components that are used to perform an image forming operation, and a drive controller that controls a potential noise source component or a component group containing plural potential noise source components among the plural components to be sequentially driven in an operation state for specifying a noise occurrence place such that a component or a component group having a higher possibility to be a noise source is driven with higher priority or a component or a component group having a lower possibility to be the noise source with lower priority.

A recording material determination device includes a transmission unit, a drive unit, a reception unit, and a control unit. The drive unit outputs a drive signal for transmitting an ultrasonic wave from the transmission unit to the reception unit. The control unit determines a type of a recording material, based on a first value of the ultrasonic wave through the recording material received by the reception unit in a first mode for outputting a first number of drive signals from the drive unit in a first period, and a second value of the ultrasonic wave through the recording material received by the reception unit in a second mode for outputting a second number of drive signals from the drive unit in a second period. The second number of drive signals is greater than the first number of drive signals.

A stored object detection device includes: a radar sensor which emits a radio wave and detects a reflected wave; a reflector which reflects the radio wave emitted from the radar sensor; and a detection target object storage amount detector which detects a storage amount of a detection target object in a container, based on a reflected wave of the radio wave that has been reflected on the container containing the detection target object, a reflected wave of the radio wave that has passed through the container and has been reflected on the detection target object, and a reflected wave of the radio wave that has passed through the container and has been reflected on the reflector.

An image forming apparatus includes a stack portion having recording materials, an image forming unit, a basis weight detection unit, an operating sound detection unit, and a mode selection unit. The basis weight detection unit detects a recording material basis weight based on an ultrasonic wave. The operating sound detection unit detect an abnormality of a generated operating sound. The mode selection unit selects, for each recording material fed to the image forming unit, between transmitting to the basis weight detection unit a first instruction for detecting the recording material basis weight and transmitting to the operating sound detection unit a second instruction for detecting the operating sound abnormality. In determining an interval at which each second instruction is transmitted, the mode selection unit determines the interval so that the interval and a cycle, in which properties of recording materials on the stack portion are repeated, do not continuously coincide.

An image forming apparatus includes an image forming unit having a plurality of members, a control unit, and a sound collecting unit. The control unit controls operations of the plurality of members in a first operation mode in which the image forming unit forms an image on a recording material. The sound collecting unit collects a sound that arises in the image forming apparatus during the first operation mode execution to generate a sound signal. When it is determined, based on the generated sound signal, that an abnormal sound has arisen, the control unit determines a source of the abnormal sound by transitioning to a second operation mode after the first operation mode has ended and causing, in the second operation mode, one or more members, from the plurality of members, that are possible sources of the abnormal sound to operate separately from the remaining plurality of members.

A recording material determination device includes a transmission unit, a drive unit, a reception unit, and a control unit. The drive unit outputs a drive signal for transmitting an ultrasonic wave from the transmission unit to the reception unit. The control unit determines a type of a recording material, based on a first value of the ultrasonic wave through the recording material received by the reception unit in a first mode for outputting a first number of drive signals from the drive unit in a first period, and a second value of the ultrasonic wave through the recording material received by the reception unit in a second mode for outputting a second number of drive signals from the drive unit in a second period. The second number of drive signals is greater than the first number of drive signals.