Toa Corporation

Etani Electronics Co., Ltd.

Ricoh Company, Ltd.

Shokichiro Hino

Daisuke Higashihara

Koichi Tsuchiya

Tomohiko Endo

Yasushi Nakazato

Masahide Yamashita

Jun Yamane

Osamu Satoh

Kohji Ue

In an image forming apparatus, a cleaning blade cleans residual toner adhered on the surface of an image carrier and a sound sensor collects a sound generated inside a casing of the image forming apparatus. A determining unit determines, based on the sound collected by the sound sensor, whether cleaning failure has occurred in the cleaning blade. The determining unit makes the determination based on at least intensity of a first sound component that is a sound component of a first frequency and intensity of a second sound component that is a sound component of a second frequency different from the first frequency.

Image forming apparatus including a sound sensor to determine cleaning failure

Resonant frequencies fand fdetected in a resonant space are determined as center frequencies of a dip. Based on measurement values at a speaker and a microphone in the resonant space, a basic amplitude frequency characteristic Ca and a target amplitude frequency characteristic Cd are found. A smoothness degree on a frequency axis is larger in the target amplitude frequency characteristic Cd than the basic amplitude frequency characteristic Ca. A damping level and quality factor of the dip are determined based on a difference between the basic amplitude frequency characteristic Ca and the target amplitude frequency characteristic Cd in the center frequencies fand fof the dip and frequencies near the center frequencies.

Dip filter frequency characteristic decision method

A devicefor measuring a propagation time of a sound wave comprises a sound source meansand a calculation means. The sound source meansoutputs a time stretched pulse as a sound source signal input to a speaker. The calculation meanscalculates a cross-correlation function of the time stretched pulse and the sound signal which is output from the speakerand is received in a microphone. Based on the cross-correlation function, the propagation time of the sound wave between the speakerand the microphoneis found.

Method and device for measuring sound wave propagation time between loudspeaker and microphone

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Tokyo, Japan

Shokichiro Hino