US 11,856,164 B2
Transport apparatus, image scanner, and printer comprising a transmitter, receiver, a long-distance sound field, selecting a beam diameter from a plurality of beam diameters at a short-distance sound field limit distance
Eiji Osawa, Matsumoto (JP)
Assigned to SEIKO EPSON CORPORATION, Tokyo (JP)
Filed by SEIKO EPSON CORPORATION, Tokyo (JP)
Filed on Dec. 28, 2020, as Appl. No. 17/134,927.
Claims priority of application No. 2019-235873 (JP), filed on Dec. 26, 2019.
Prior Publication US 2021/0203801 A1, Jul. 1, 2021
Int. Cl. H04N 1/00 (2006.01); H04N 1/12 (2006.01); G01B 17/02 (2006.01)
CPC H04N 1/00599 (2013.01) [G01B 17/02 (2013.01); H04N 1/00716 (2013.01); H04N 1/00729 (2013.01); H04N 1/123 (2013.01)] 9 Claims
OG exemplary drawing
 
1. A transport apparatus, comprising:
a transport path on which a medium is transported;
a transmitter including a first ultrasonic wave transducer configured to transmit an ultrasonic wave;
a receiver including a second ultrasonic wave transducer configured to receive the ultrasonic wave, wherein
the transport path is provided between the transmitter and the receiver,
the transport path is provided in a long-distance sound field of the ultrasonic wave transmitted from the transmitter, and i
n the long-distance sound field, a sound pressure distribution of the ultrasonic wave transmitted from the transmitter corresponds to a Cauchy distribution; and
a first guide provided between the transport path and the transmitter, wherein
the long-distance sound field of the ultrasonic wave corresponds to a field from a position of the first guide,
the first guide includes a first through-hole through which the ultrasonic wave transmitted from the transmitter passes,
the transport path is positioned closer to the receiver than the first through-hole,
a distance between the first through-hole and the transmitter is a short-distance sound field limit distance of the ultrasonic wave transmitted from the transmitter,
at the short-distance sound field limit distance, a beam diameter of a plurality of beam diameters of the ultrasonic wave transmitted from the transmitter is smallest among the plurality of beam diameters, wherein each of the plurality of beam diameters are associated with distinct cases where transmission surfaces with a circular shape contain different diameters and different short-distance sound field limit distances,
and To>T1>TN, wherein To is a projection area obtained by projecting a transmission surface that transmits the ultrasonic wave of the transmitter on the first guide along a sound axis, Ti is an opening area of the first through-hole, and TN is a cross-sectional area of a beam cross-section parallel to the transport path at the short-distance sound field limit distance of the ultrasonic wave transmitted from the transmitter.