A natural frequency measuring device includes a receiving unit and a measuring unit. The receiving unit receives information of an image formed on a recording medium with vibrations of different frequencies provided to a member used to form the image. The measuring unit measures a natural frequency of the member from a frequency response characteristic using a misregistration amount of the image represented by the information of the image received by the receiving unit.

An image forming system includes an image forming apparatus and a management apparatus. The image forming apparatus includes a variable mechanism, a physical quantity detection unit that detects a change in physical quantity caused when a state of the variable mechanism changes, an abnormality detection unit that detects an abnormal condition, and a transmission unit that transmits detection results of the physical quantity detection unit and the abnormality detection unit to the management apparatus. The management apparatus includes a determination unit that determines a cause of the abnormal condition, and a notification unit that provides a notification that the abnormal condition is caused by a change in the state in accordance with a determination result. The determination unit determines that the abnormal condition is caused by a change in the state when the abnormal condition is detected after the change in physical quantity exceeds a threshold.

An image forming apparatus includes an image forming unit, a transmission unit, a reception unit, a control unit configured to obtain a time period until the reception unit receives a first ultrasonic wave via a first recording material and an amplitude value thereof at a reference temperature, obtain a time period until the reception unit receives a second ultrasonic wave via a second recording material and an amplitude value thereof at a different temperature, control an image formation condition for forming the image on the first recording material on the basis of the amplitude value of the first ultrasonic wave, obtain a difference time period between reception of the first and second ultrasonic waves, and control an image formation condition for forming the image on the second recording material on the basis of the difference time period and the amplitude value of the second ultrasonic wave.

A control unit determines sheet information based on a result of detection performed by a media sensor, and in a case where a threshold is changed after the determined sheet information is displayed on a display, the control unit determines sheet information based on the result of the detection and the changed threshold, and the display displays the sheet information.

An image processing apparatus includes circuitry configured to obtain audio data of audio collected through a microphone, determine whether the audio data has a noise level equal to or less than a threshold to generate a determination result, record the audio data when the determination result indicates that the noise level of the audio data is equal to or less than the threshold, and add the recorded audio data to image data.

A sound absorber, which is included in a sheet feeder included in an image reading device, an image forming apparatus, and an electronic device, includes a cavity, a communication portion through which the cavity communicates with an outside of a sheet feeder, and a communication direction changing device configured to change a communication direction of the communicating portion.

An image forming apparatus includes an image forming unit for forming an image on a recording material, a first detection unit including a transmission unit for transmitting an ultrasonic wave and a reception unit for receiving the transmitted ultrasonic wave, first and second conveyance units for conveying the recording material, and a control unit. The first and second conveyance units form a loop on the recording material by conveying the recording material at different speeds. The control unit controls an image forming condition for forming an image on the recording material by the image forming unit, based on the ultrasonic wave received via the recording material in a period in which no loop is formed on the recording material by the first and second conveyance units.

An image forming apparatus includes an image forming unit for forming an image on a recording material, a first detection unit including a transmission unit for transmitting an ultrasonic wave and a reception unit for receiving the transmitted ultrasonic wave, first and second conveyance units for conveying the recording material, and a control unit. The first and second conveyance units form a loop on the recording material by conveying the recording material at different speeds. The control unit controls an image forming condition for forming an image on the recording material by the image forming unit, based on the ultrasonic wave received via the recording material in a period in which no loop is formed on the recording material by the first and second conveyance units.

A sound diagnosis system includes: a setting unit configured to set a threshold for each of a plurality of time sections, based on a sound wave level in each of the plurality of time sections of a plurality of first sound data classified in a first group; and a determination unit configured to determine whether or not an abnormal sound is generated by calculating a comparison value for each of the plurality of time sections based on a sound wave level in each of the plurality of time sections of one or more second sound data classified in the first group, and comparing the comparison value for each of the plurality of time sections with the threshold value of the corresponding time section of the first group, the threshold value being set by the setting unit.

A determination device includes a processor that is used for determining first paper having a surface on which an embossing process is performed and second paper having a surface on which the embossing process is not performed, a light source that irradiates a surface of paper with light, a light detector that receives the light transmitted through the paper and that detects a light transmittance, an ultrasonic transmitter that transmits an ultrasonic wave to the surface of the paper, and an ultrasonic receiver that receives the ultrasonic wave transmitted through the paper and that detects an ultrasonic transmittance, in which the processor is configured to: use an index that is stored in advance in a storage device and that indicates a correlation between the light transmittance and the ultrasonic transmittance in the second paper, and determine whether or not the paper is the first paper or the second paper according to whether or not the light transmittance and the ultrasonic transmittance, which are detected from the paper, are apart from the index by a predetermined threshold value or more.