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 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.

According to some embodiments, a double detection apparatus for a mail-piece inserter includes a detectable flag affixed to a rotating mail-piece gripper of a mail-piece rotary feeder. A stationary proximity sensor may generate a voltage output based on a presence of the detectable flag in a direction along a first axis normal to the rotation of the mail-piece gripper. A decision unit may then generate a double detect alert signal when a phase shift above a pre-determined threshold value is detected in the voltage output generated by the stationary proximity sensor. According to some embodiments, the decision unit may also generate a thin detect alert signal when a phase shift past another pre-determined threshold value is detected in the voltage output generated by the stationary proximity sensor.

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 medium conveying apparatus includes a medium tray, a feed roller to feed a medium placed on the medium tray, a brake roller facing the feed roller, a pressing member to press the brake roller to the feed roller side, a processor to detect media multi-feed, and control the feed roller and the brake roller in such a way that the medium is reset to the medium tray when the media multi-feed of media is detected. The processor controls the pressing member in such a way that a pressing force of the brake roller when resetting the medium to the medium tray is greater than a pressing force of the brake roller when feeding the medium.

A medium conveying apparatus includes a medium tray, a feed roller to feed a medium placed on the medium tray, a brake roller facing the feed roller, a pressing member to press the brake roller to the feed roller side, a processor to detect media multi-feed, and control the feed roller and the brake roller in such a way that the medium is reset to the medium tray when the media multi-feed of media is detected. The processor controls the pressing member in such a way that a pressing force of the brake roller when resetting the medium to the medium tray is greater than a pressing force of the brake roller when feeding the medium.

Provided is a sheet conveying device capable of suppressing the recurrence of overlapped feeding in accordance with the detection of overlapped feeding. The sheet conveying device includes a paper-supply roller and a conveying roller. A sheet-detecting unit detects a leading edge position of a sheet. An overlapped-feeding-detecting unit detects overlapped-feeding of sheets. An overlapped-feeding-distance-calculating unit, based on detection results, calculates an overlapped-feeding distance in which sheets are overlapped. A conveyance-control unit causes the paper-supply roller to stop at a timing when a position separated a set length in a sheet-conveyance direction from a sheet trailing edge reaches the paper-supply roller. The conveyance-control unit, in a case where detection of overlapped feeding by the overlapped-feeding-detecting unit occurs a plurality of times, extends the set length based on the overlapped-feeding distance.