A printing apparatus includes a feeding roller configured to feed a printing sheet stacked on a stacking unit, a conveyance roller configured to convey the printing sheet fed by the feeding roller, a printing unit configured to print the printing sheet conveyed by the conveyance roller, a conveyance control unit configured to control conveyance of printing sheets so that the trailing edge of a preceding sheet as a printing sheet precedingly fed from the stacking unit and the leading edge of a succeeding sheet as a printing sheet succeedingly fed from the stacking unit overlap each other, and a determination unit configured to determine whether to convey the succeeding sheet to a position facing the printing unit while keeping an overlap state between the preceding sheet and the succeeding sheet.

A sheet processing apparatus, comprising a thickness detecting device, the thickness detecting device including: a plurality of conductive displacement members; a plurality of resonance circuits that are disposed to correspond to the plurality of displacement members, each include a coil facing the corresponding displacement member and a capacitor, and neighboring resonance circuits resonate at different resonance frequencies; and a calculator that calculates a thickness of the sheet based on impedance values of the plurality of resonance circuits and the plurality of displacement members.

A printing apparatus includes a feeding roller configured to feed a printing sheet stacked on a stacking unit, a conveyance roller configured to convey the printing sheet fed by the feeding roller, a printing unit configured to print the printing sheet conveyed by the conveyance roller, a conveyance control unit configured to control conveyance of printing sheets so that the trailing edge of a preceding sheet as a printing sheet precedingly fed from the stacking unit and the leading edge of a succeeding sheet as a printing sheet succeedingly fed from the stacking unit overlap each other, and a determination unit configured to determine whether to convey the succeeding sheet to a position facing the printing unit while keeping an overlap state between the preceding sheet and the succeeding sheet.

A transmitter transmits ultrasound to the conveyance path. A receiver receives the ultrasound. A double-feed detector detects whether or not double-feed of a plurality of sheets has occurred. A controller causes the transmitter to transmit ultrasound at a first burst interval when determining the threshold value, and causes the transmitter to transmit ultrasound at a second burst interval, which is shorter than the first burst interval, when detecting the double-feed of sheets. A double-feed detector determines a threshold value that enables distinction between double-feed and single-feed.

Provided is a transport device including a first transport section that is driven at a first transport speed and transports a recording medium interposed therein, a second transport section that is driven at a speed different from the first transport speed, is located at a downstream of the first transport section in a transport direction, and transports the recording medium interposed therein, a detection section that detects variations in a driving load of the second transport section before and after the recording medium is discharged from the first transport section, and a derivation section that derives a thickness of the recording medium based on the variations.

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 conveying apparatus includes a conveying roller to convey a medium, an overlap detection sensor, a processor to detect an overlap portion in which it is determined that an overlap has occurred on the medium based on a detection output by the overlap detection sensor for the medium conveyed by the conveying roller, calculate an overlap length where the overlap portion is continuous based on a detection result of the overlap portion, determine whether a multi-feed has occurred based on the overlap length, and execute an abnormal processing for the multi-feed based on a determination result of the multi-feed. The processor determines that a first overlap portion and a second overlap portion are continuous when a distance between the first overlap portion and the second overlap portion is within a predetermined distance in calculating the overlap length.

Provided are a medium conveyance apparatus, control method, and control program to enable determining whether multi-feed of a medium has occurred by a greater precision. A medium conveyance apparatus includes a storage device to store in advance region information of a predetermined region in a medium, a feed roller to feed the medium, a slant detection module to detect an amount of slant of the fed medium, an overlap detection module to detect region information of a region in which overlap has occurred in the fed medium, a correction module to correct the detected region information based on the amount of slant, and a multi-feed determination module to determine that multi-feed of the medium has occurred if the corrected region information does not correspond to the stored region information and determine that multi-feed of the medium has not occurred if the corrected region information corresponds to the stored region information.

An image reading device includes: a transport unit configured to transport a medium; an emission unit configured to emit an ultrasonic wave in accordance with a driving voltage and a reception unit configured to receive the ultrasonic wave, the emission unit and the reception unit being disposed so that a transport path for the medium transported by the transport unit is interposed therebetween; a reading unit configured to read the medium; and a control unit configured to detect presence or absence of multi-feed of the medium on the basis of a signal received by the reception unit. The image reading device is configured to switch a posture into any of a first posture or a second posture. The first posture is a posture in which the transport path is sloped relative to a mounting surface. The second posture is a posture in which an angle of the transport path relative to the mounting surface is smaller than that in the first posture. The control unit sets a first driving voltage as the driving voltage when the posture is the first posture, and sets a second driving voltage lower than the first driving voltage as the driving voltage when the posture is the second posture.

An ultrasonic detection unit includes a transmission sensor chip, a reception sensor chip, a transmission substrate provided with the transmission sensor chip, and a reception substrate provided with the reception sensor chip. The reception substrate is provided with an amplifier that amplifies a reception signal of an ultrasonic wave received by the reception sensor chip, and a shielding member that covers at least a part of the amplifier. A height of the reception sensor chip with respect to the reception substrate is lower than a height of the shielding member with respect to the reception substrate.