Abstract: A sheet feeding apparatus includes two transport devices arranged in a sheet guide that guides a sheet from a stacker to a processing position for reading an image or printing. A double feed detection device is arranged between the transport devices for detecting a double feed of the sheets over a predetermined length region (measurement length). A sheet length recognition device is provided for recognizing at least two portions of a length of the sheet stacked on the stacker in a transport direction, and a judgment device is provided for judging the double feed of the sheets based upon detection data from the double feed detection device. The judgment device judges the double feed of the sheets according to detection data of one measurement region selected from a plurality of measurement regions based on information obtained from the sheet length recognition device.

Abstract: A sheet feeding apparatus includes a sheet size recognition device for recognizing length of a sheet placed on a stacker in a transport direction, an ultrasonic double feed detection device arranged between a first transport device and a second transport device for detecting a double feed of sheets, and a transport length detection device for detecting a transport length of the sheet transported by the first and second transport devices from a leading edge of the sheet to a trailing edge of the sheet. A comparison device compares the length of the sheet recognized by the sheet size recognition device and the transport length of the sheet detected by the transport length detection device. A judgment device judges the double feed of the sheets based on at least one of a comparison result from the comparison device and a detection result from the double feed detection device.

Abstract: A sheet handling apparatus includes a sheet stacker for stacking sheets; a separating device for separating and feeding the sheets stacked on the sheet stacker; and a register roller disposed adjacent to the separating device for correcting a skew of the sheet. An ultrasonic wave sensor composed of a wave sending sensor and a wave receiving sensor is arranged between the separating device and the register roller obliquely relative to a surface of the sheet. A judging device is electrically connected to the ultrasonic wave sensor for detecting a double feed of the sheets based upon an output signal from the wave receiving sensor at a predetermined time after the register roller starts rotating. A control device electrically connected to the judging device and the register roller controls the register roller to stop and rotate.

Abstract: A sheet supplying device includes a stacker for placing sheets; a delivery device for separating and feeding the sheets on the stacker; a register device for temporarily holding a sheet; a sheet conveying guide for guiding the sheet from the register device to a processing position; a sheet sensor disposed between the delivery device and the register device for detecting the sheet; at least one driving device for driving the delivery device and the register device; a conveyance control device for controlling the driving device so that the delivery device and the register device form a loop of the sheet according to a signal from the sheet sensor and an overlap sensor disposed between the register device and the processing position for detecting overlapping of the sheet. An overlap determining device determines overlapping of the sheet according to signals from the sheet sensor and the overlap sensor.

Abstract: A sheet feeding device includes a stacker on which sheets are placed, a sheet feeding device for separating and feeding a sheet from other sheets on the stacker, a sheet overlap sensing device placed in a sheet conveying path at a downstream side of the sheet feeding device, and a sheet sensing device for detecting whether the sheet is located in the sheet overlap sensing device. An error determining device determines whether the sheet overlap sensing device is operating normally.

Abstract: A sheet feeding apparatus includes first and second transport devices disposed at a transport guide with a distance in between for nipping and transporting a sheet, and a double feed detection device disposed between the first transport device and the second transport device for detecting a double feed of the sheet. A sheet end detection device is disposed at a downstream side of the first transport device for detecting a trailing end of the sheet, and a determination device is provided for determining the double feed based on a detection signal from the double feed detection device and a detection signal from the sheet end detection device.

Abstract: A sheet feeding apparatus includes a stacker for stacking a sheet; a sheet separating device for sequentially separating and feeding the sheet stacked on the stacker; a sheet transport guide for guiding the sheet from the separating device to a processing position; and an ultrasonic wave sensor arranged between the separating device and the processing position for detecting the sheet. The ultrasonic wave sensor has a wave sending element for emitting an ultrasonic wave with a predetermined frequency and a wave receiving element for receiving the ultrasonic waves from the wave sending element. The wave sending element is arranged at a lower position in a direction of gravity relative to the sheet transport guide. The wave receiving element is arranged at an upper position opposite to the lower position, and has a wave sending surface inclined with an angle relative to a horizontal direction.

Abstract: A sheet feeding apparatus includes a sheet size recognition device for recognizing length of a sheet placed on a stacker in a transport direction, an ultrasonic double feed detection device arranged between a first transport device and a second transport device for detecting a double feed of sheets, and a transport length detection device for detecting a transport length of the sheet transported by the first and second transport devices from a leading edge of the sheet to a trailing edge of the sheet. A comparison device compares the length of the sheet recognized by the sheet size recognition device and the transport length of the sheet detected by the transport length detection device. A judgment device judges the double feed of the sheets based on at least one of a comparison result from the comparison device and a detection result from the double feed detection device.

Abstract: A sheet feeding device includes a stacker on which sheets are placed, a sheet feeding device for separating and feeding a sheet from other sheets on the stacker, a sheet overlap sensing device placed in a sheet conveying path at a downstream side of the sheet feeding device, and a sheet sensing device for detecting whether the sheet is located in the sheet overlap sensing device. An error determining device determines whether the sheet overlap sensing device is operating normally.

Abstract: A sheet feeding apparatus includes a stacker for stacking a sheet; a feeding device for feeding the sheet on the stacker to a predetermined processing position; a drive device for driving the feeding device; a double feed detection device having a sending element and a receiving element arranged at a downstream side of the feeding device for detecting a double feed of the sheet; a sensitivity adjustment device for comparing a detected value of the receiving element with a predetermined reference value for adjusting an output of the sending element; and a control device for controlling a transport speed of the feeding device. The sensitivity adjustment device adjusts the output of the sending element when the control device controls the drive device to stop the sheet or to decelerate the sheet at a predetermined speed.

Abstract: A sheet feeding apparatus includes a stacker for stacking a sheet; a sheet separating device for sequentially separating and feeding the sheet stacked on the stacker; a sheet transport guide for guiding the sheet from the separating device to a processing position; and an ultrasonic wave sensor arranged between the separating device and the processing position for detecting the sheet. The ultrasonic wave sensor has a wave sending element for emitting an ultrasonic wave with a predetermined frequency and a wave receiving element for receiving the ultrasonic waves from the wave sending element. The wave sending element is arranged at a lower position in a direction of gravity relative to the sheet transport guide. The wave receiving element is arranged at an upper position opposite to the lower position, and has a wave sending surface inclined with an angle relative to a horizontal direction.

Abstract: A sheet feeding apparatus includes first and second transport devices disposed at a transport guide with a distance in between for nipping and transporting a sheet, and a double feed detection device disposed between the first transport device and the second transport device for detecting a double feed of the sheet. A sheet end detection device is disposed at a downstream side of the first transport device for detecting a trailing end of the sheet, and a determination device is provided for determining the double feed based on a detection signal from the double feed detection device and a detection signal from the sheet end detection device.

Abstract: A sheet supplying device includes a stacker for placing sheets; a delivery device for separating and feeding the sheets on the stacker; a register device for temporarily holding a sheet; a sheet conveying guide for guiding the sheet from the register device to a processing position; a sheet sensor disposed between the delivery device and the register device for detecting the sheet; at least one driving device for driving the delivery device and the register device; a conveyance control device for controlling the driving device so that the delivery device and the register device form a loop of the sheet according to a signal from the sheet sensor and an overlap sensor disposed between the register device and the processing position for detecting overlapping of the sheet. An overlap determining device determines overlapping of the sheet according to signals from the sheet sensor and the overlap sensor.

Abstract: A sheet feeding apparatus includes two transport devices arranged in a sheet guide that guides a sheet from a stacker to a processing position for reading an image or printing. A double feed detection device is arranged between the transport devices for detecting a double feed of the sheets over a predetermined length region (measurement length). A sheet length recognition device is provided for recognizing at least two portions of a length of the sheet stacked on the stacker in a transport direction, and a judgment device is provided for judging the double feed of the sheets based upon detection data from the double feed detection device. The judgment device judges the double feed of the sheets according to detection data of one measurement region selected from a plurality of measurement regions based on information obtained from the sheet length recognition device.

Abstract: A sheet handling apparatus includes a sheet stacker for stacking sheets; a separating device for separating and feeding the sheets stacked on the sheet stacker; and a register roller disposed adjacent to the separating device for correcting a skew of the sheet. An ultrasonic wave sensor composed of a wave sending sensor and a wave receiving sensor is arranged between the separating device and the register roller obliquely relative to a surface of the sheet. A judging device is electrically connected to the ultrasonic wave sensor for detecting a double feed of the sheets based upon an output signal from the wave receiving sensor at a predetermined time after the register roller starts rotating. A control device electrically connected to the judging device and the register roller controls the register roller to stop and rotate.

Abstract: A control device for a system interconnection inverter. The control device includes an active/reactive current reference generator and an active/reactive current detector for detecting an output AC current of the inverter. The control device further includes a phase detector, a frequency detector, and a voltage amplitude detector of the AC voltage of the inverter. The control device also includes a frequency reference generator and a voltage amplitude reference generator. The control device also includes a frequency correction computing circuit and a voltage amplitude correction computing circuit. The control device further includes an adder for adding the active current reference signal and the voltage amplitude correction signal to output as an active current correction reference signal, and for adding the reactive current reference signal and the frequency correction signal to output as a reactive current correction signal.

Abstract: An inverter control device that controls a self-commulated inverter connected to an AC power system via a three phase transformer and in so doing suppresses DC magnetization in the three-phase transformer. The device includes a current DC component detecting circuit for detecting the current DC components contained in at least two of the three phase output AC currents of the inverter and a DC magnetization suppressor signal generating circuit for producing two correcting signals from the current DC components. The two correcting signals are used to balance in amount the three voltage DC components contained in the three phase output AC voltage of the inverter, respectively. An output reference correcting circuit is provided to correct two of first output references in accordance with the two correcting signals and output three second references including the two corrected values and one of the first output reference.

Abstract: A reactive power controller for controlling a reactive power output from a self-commutated inverter capable of eliminating an uncontrolled reactive power at the starting moment of its operation. The reactive power controller includes a device for producing a signal indicating amounts to be adjusted of an amplitude and a phase of an output AC voltage of the self-commutated inverter, in accordance with a DC voltage over a DC capacitor and an AC voltage of an AC system power source, and a device for adjusting the amplitude and the phase of the output AC voltage of the self-commutated inverter in accordance with the indication of the producing device.

Abstract: A coupling system in which power converters are coupled through a DC circuit to exchange active power between the converters comprises a control apparatus for controlling active power exchanged between each converter and its AC system. The control apparatus includes an automatic active power regulator for regulating active power exchanged between the converters and the AC system to be equal to be predetermined active power reference value, and an automatic DC voltage regulator for regulating a DC voltage of the DC circuit to be equal to a predetermined DC voltage reference value. When an output signal from the automatic active power requlator of each converter is input as an upper limit value of an output signal from the automatic DC voltage regulator, a DC voltage reference value of one converter is set to be equal to or larger than a DC voltage reference value of the remaining power converter.

Abstract: A reactive power controller for a reactive power output from a self-commutated inverter connected to an AC system power source via an AC reactor, the inverter alternatively acting as a capacitor or a reactor, in which an operating unit produces a DC reference voltage for the inverter from a reactive power reference signal and a system power voltage. A differential operation device produces a phase difference angle for the inverter, in which a phase controller outputs firing pulses for controllable rectifier elements of the inverter according to the phase difference angle. An output AC voltage of the inverter is controlled by varying a supply of an active power from the inverter or the system power source to the latter or the former according to the phase difference angle so that the DC voltage of the inverter may be equal to the DC reference voltage.