A system for detecting envelopes from multi-fed documents in a scanning system with a scanning track along which documents move laterally toward a scanning station having a plurality of spaced apart penetrating detectors across the scanning track. The scanners detect a leading edge as a single layer material, i.e. without an air gap and the interior as having an air gap in the document scanned. If a document has an interior air gap, but the leading edge does not, it is first assumed to be an envelope.

A multifeed detection device that detects multifeed by using an ultrasonic wave includes an ultrasonic emitting unit and an ultrasonic receiving unit arranged to oppose each other with a medium transport path interposed therebetween; judges occurrence of multifeed of media based on a detection intensity of an ultrasonic wave received by the ultrasonic receiving unit, and a multifeed threshold for judging multifeed of media; and acquires first information that is information relating to adjustment for the multifeed threshold, and second information for specifying that the first information is the information relating to the adjustment for the multifeed threshold, from a calibration sheet holding the first information and the second information.

The automatic document feeder includes a multi-feed detection sensor unit, a sensor control unit, and a control board on which the sensor control unit is mounted. The multi-feed detection sensor unit includes a transmission board on which a transmission sensor and a detection circuit of a drive current of the transmission sensor are mounted, a reception board on which a reception sensor and an amplifier circuit of a reception signal of the reception sensor are mounted, and a relay board on which a drive circuit of the transmission sensor is mounted. The sensor control unit stores first fault information indicating that the relay board is disconnected if the relay board is disconnected, stores second fault information indicating that the reception board is at fault if an output value of the amplifier circuit is equal to or less than a first threshold, stores third fault information indicating that the transmission board is at fault if the detection circuit does not detect the drive current, and stores fourth fault information indicating that the transmission sensor or the reception sensor is damaged if the output value of the amplifier circuit is equal to or less than a second threshold. If the fault information is stored, the sensor control unit transmits, to an image forming apparatus, an instruction signal for causing the fault information to be displayed.

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.

A sheet conveyance device includes a transmitter circuit, a receiver circuit, an integrator circuit which performs charging of electric charge outputted from the transmitter circuit and outputs a judgment voltage, a drive circuit, and a control circuit. The drive circuit feeds a drive signal to the transmitter circuit. At a lapse of a wait time after changing a level of a transmission instruction signal to a level instructing to feed the drive signal to the transmitter circuit, the control circuit makes the integrator circuit start to perform charging. When adjusting the wait time, the control circuit performs processing for adjustment a plurality of times. The control circuit makes the wait time different in each execution of the processing for adjustment. The control circuit determines a new wait time based on a magnitude of the judgment voltage recognized in each execution of the processing for adjustment.

A method for operating a paper feed system for use in a printing apparatus that detects multi-feeds and separates all sheets while allowing a single sheet to continue is disclosed. The separation method controls a motor for the separator roller that can be torque controlled, allowing varying torques depending on media type and/or user input. The separation method detects multi-feeds, correct the multi-feed, and ultimately feeds one sheet at a time through the automatic document feeder.

A paper feed system for use in a printing apparatus that detects multi-feeds and separates all sheets while allowing a single sheet to continue is disclosed. The separation system uses a motor for the separator roller that can be torque controlled, allowing varying torques depending on media type and/or user input. The separation system can also detect multi-feeds, correct them, and ultimately feed one sheet at a time through the automatic document feeder.

A medium processing apparatus includes: an ultrasonic oscillator; an ultrasonic sensor arranged at a position that opposes the ultrasonic oscillator interposing a transport path of a medium; an amplification circuit configured to amplify an output signal of the ultrasonic sensor; an integration circuit configured to integrate an output signal of the amplification circuit; a discharge circuit configured to perform discharge of an electric charge of a power storage circuit included in the integration circuit; and a determination circuit configured to determine whether or not multi-feed of the medium occurs on the basis of an output signal of the integration circuit, in which the discharge circuit stops, after performing discharge over a first period or more, the discharge, and after a second period has passed, the determination circuit performs a first (an initial) determination whether or not the multi-feed of the medium occurs.

Provided is a sheet conveyance apparatus armored with a housing, the sheet conveyance apparatus includes: a sheet conveyor that feeds a sheet to a downstream side in a direction of conveyance; a conveyance guide that guides the sheet to be conveyed; an ultrasonic sensor that detects the sheet guided by the conveyance guide; and a shield member that is conductive, wherein the ultrasonic sensor includes: a transmitter that transmits an ultrasonic wave having a predetermined frequency; and a receiver that receives the ultrasonic wave, the transmitter and the receiver are arranged along the conveyance guide, and the shield member is disposed between the housing and the receiver in a sheet-face perpendicular direction at an ultrasonic-irradiation position of the sheet being conveyed, the shield member covering an entirety of the receiver in plan view in the sheet-face perpendicular direction.

A transport device includes: a medium support unit having a placement surface where a sheet-like medium is placed; a transport unit supplied with the medium placed at the placement surface and transporting the medium in a transport direction along a sheet surface of the medium; an ultrasonic transmitting unit provided at a part of the medium support unit and transmitting an ultrasonic wave; an ultrasonic receiving unit provided at another part of the medium support unit, and receiving the ultrasonic wave and outputting a received signal; and a floating detection unit determining whether a floating of the medium from the placement surface is present or not, based on the received signal.