Abstract: A sheet conveying apparatus capable of conveying a sheet as a conveyance target in a conveyance path includes a detector that detects capacitance in a predetermined detection region in the conveyance path; and a basis weight identifier that identifies a basis weight of the sheet as the conveyance target on the basis of first capacitance detected by the detector while the sheet as the conveyance target does not pass through the detection region and second capacitance detected by the detector while the sheet as the conveyance target passes through the detection region.

Abstract: A power supply device includes: a first transformer including a primary winding and a secondary winding; a first control circuit controlling a switching operation of a switch element, and cause the primary winding to generate a first AC voltage; an application circuit receiving a second AC voltage generated in the secondary winding by mutual induction with the primary winding, and apply an output voltage according to the second AC voltage to a load; a voltage detection circuit detecting a magnitude of a DC voltage obtained by rectifying the first AC voltage or the second AC voltage; and an output circuit outputting a stop signal indicating stop of the power supply device, when a result of comparison between the magnitude of the DC voltage and a threshold value set according to a magnitude of the load satisfies a predetermined condition, after reception of an instruction to stop voltage supply.

Abstract: A phase control device includes: at least one switching element connected to an AC power source, the switching element being capable of: turning on and off at specified timings; delivering AC power to a load upon turn-on and cutting it off upon turn-off; and keeping an on-time from the start to the end of turn-on and an off-time from the start to the end of turn-off, the on-time and off-time being variable; a timing setting portion that sets a turn-on and turn-off timing for turning on and off the switching element; a judgment portion that judges whether or not the turn-on and turn-off timing are on at a phase within a first or second phase range; and a processor that starts turning on and off the switching element at the turn-on and turn-off timing, the processor being capable of adjusting the on-time and off-time depending on the judgment result.

Abstract: A power supply control device including a chopper circuit generating a heater current for a halogen heater, a current feedback circuit generating a current feedback signal indicating a current amount based on an amount of the heater current, and a constant current circuit performing pulse-width modulation of the heater current amount according to a difference between a target heater current amount and the current amount indicated by the current feedback signal. The current feedback circuit switches between methods at least including a first method and a second method for generating the current feedback signal. The current feedback signal indicates a greater current amount with the first method than with the second method, and the current feedback circuit uses the first method during a period with a predetermined time length starting from when the halogen heater is turned on, and uses the second method after elapse of the period.

Abstract: A power supply device having a transformer and a control circuit for controlling a power input to the transformer in accordance with a set value of an output voltage is provided. The power supply device includes an auxiliary winding provided in the transformer and a control power supply circuit configured to rectify AC power produced in the auxiliary winding to output a control voltage for operating the control circuit. The control power supply circuit includes a smoothing capacitor which is connected between output terminals for the control voltage and is to be charged with power obtained by rectifying the AC power, and a charge thinning circuit configured to intermittently charge the smoothing capacitor so that a voltage value between both ends of the smoothing capacitor reaches a set value of the control voltage.

Abstract: A sheet conveying apparatus capable of conveying a sheet as a conveyance target in a conveyance path includes a detector that detects capacitance in a predetermined detection region in the conveyance path; and a basis weight identifier that identifies a basis weight of the sheet as the conveyance target on the basis of first capacitance detected by the detector while the sheet as the conveyance target does not pass through the detection region and second capacitance detected by the detector while the sheet as the conveyance target passes through the detection region.

Abstract: A phase control device includes: at least one switching element connected to an AC power source, the switching element being capable of: turning on and off at specified timings; delivering AC power to a load upon turn-on and cutting it off upon turn-off; and keeping an on-time from the start to the end of turn-on and an off-time from the start to the end of turn-off, the on-time and off-time being variable; a timing setting portion that sets a turn-on and turn-off timing for turning on and off the switching element; a judgment portion that judges whether or not the turn-on and turn-off timing are on at a phase within a first or second phase range; and a processor that starts turning on and off the switching element at the turn-on and turn-off timing, the processor being capable of adjusting the on-time and off-time depending on the judgment result.

Abstract: A first rectification circuit includes a bypass element connected to both ends of a rectification element. The bypass element is smaller in voltage drop amount than the rectification element. A power supply device is configured to perform switching between a first mode and a second mode based on at least one of information showing a magnitude of electric power that is being supplied to a load and information showing a magnitude of electric power that is to be supplied to the load. In the first mode, an AC voltage is rectified in a path including the rectification element. In the second mode, the AC voltage is rectified in a path including the bypass element.

Abstract: A power supply device includes: a first transformer including a primary winding and a secondary winding; a first control circuit controlling a switching operation of a switch element, and cause the primary winding to generate a first AC voltage; an application circuit receiving a second AC voltage generated in the secondary winding by mutual induction with the primary winding, and apply an output voltage according to the second AC voltage to a load; a voltage detection circuit detecting a magnitude of a DC voltage obtained by rectifying the first AC voltage or the second AC voltage; and an output circuit outputting a stop signal indicating stop of the power supply device, when a result of comparison between the magnitude of the DC voltage and a threshold value set according to a magnitude of the load satisfies a predetermined condition, after reception of an instruction to stop voltage supply.

Abstract: An image forming apparatus includes: a fixing part including a heater, and a first temperature detection part configured to detect the temperature of the heater; a chopper circuit including a reactor, a freewheeling element, and a switching element, the chopper circuit being configured to switch an input direct current on and off in a specified duty cycle by using the switching element and to supply the current to the heater; and a control part configured to control the duty cycle based on a detection result obtained by the first temperature detection part, as well as to control a switching frequency of the switching element based on an operation mode of the image forming apparatus.

Abstract: A power supply device having a transformer and a control circuit for controlling a power input to the transformer in accordance with a set value of an output voltage is provided. The power supply device includes an auxiliary winding provided in the transformer and a control power supply circuit configured to rectify AC power produced in the auxiliary winding to output a control voltage for operating the control circuit. The control power supply circuit includes a smoothing capacitor which is connected between output terminals for the control voltage and is to be charged with power obtained by rectifying the AC power, and a charge thinning circuit configured to intermittently charge the smoothing capacitor so that a voltage value between both ends of the smoothing capacitor reaches a set value of the control voltage.

Abstract: A power supply control device including a chopper circuit generating a heater current for a halogen heater, a current feedback circuit generating a current feedback signal indicating a current amount based on an amount of the heater current, and a constant current circuit performing pulse-width modulation of the heater current amount according to a difference between a target heater current amount and the current amount indicated by the current feedback signal. The current feedback circuit switches between methods at least including a first method and a second method for generating the current feedback signal. The current feedback signal indicates a greater current amount with the first method than with the second method, and the current feedback circuit uses the first method during a period with a predetermined time length starting from when the halogen heater is turned on, and uses the second method after elapse of the period.

Abstract: A first rectification circuit includes a bypass element connected to both ends of a rectification element. The bypass element is smaller in voltage drop amount than the rectification element. A power supply device is configured to perform switching between a first mode and a second mode based on at least one of information showing a magnitude of electric power that is being supplied to a load and information showing a magnitude of electric power that is to be supplied to the load. In the first mode, an AC voltage is rectified in a path including the rectification element. In the second mode, the AC voltage is rectified in a path including the bypass element.

Abstract: A power control device receiving supply of power from a power source, the power control device including: a power accumulator accumulating a part of power from the power source; a first voltage converter receiving power from the power source and the power accumulator, performing voltage conversion to a first target voltage, and supplying power with the first target voltage to a first load; a second voltage converter receiving power from the first voltage converter, performing voltage conversion to a second target voltage, and supplying power with the second target voltage to a second load; a power source monitor monitoring power from the power source; and a power controller lowering the first target voltage to a level that the second voltage converter is capable of converting to the second target voltage when the power source monitor detects that the supply of power from the power source has stopped.

Abstract: A fuser control device includes: a fusing portion having a heater; a chopper portion including a reactor, a free-wheeling element, and a switching element; and a processor portion being configured to implement a first current control during an implementation period, the implementation period including a first time interval and a second time interval, the implementation period being longer than a commercial power period, the first current control for transferring a control signal having a predetermined duty ratio to the switching element during the first time interval and transferring a control signal having a 100% duty ratio to the switching element during the second time interval.

Abstract: An image forming apparatus includes a fixing unit that includes a roller and an electric heating wire heater, a current applying circuit that applies electrical current to the electric heater wire heater, a measuring unit electrically connected to the current applying circuit and that measures a value of electrical current that flows through the electric heating wire heater, and a controller that controls the electrical current that flows through the electric heating wire heater by controlling the current applying circuit based on the electrical current value measured by the measuring unit. The controller controls the electrical current to be less than or equal to an electrical current limit value. A magnitude of the electrical current limit value is linked to a magnitude of stable state electrical current.

Abstract: Image forming apparatus comprises an electric power supply circuit board, an electric power control unit, functional circuits, and an electrical power saving circuit. The electric power control unit executes constant voltage control, to make electrical potential of a remote sensing location constant. The functional circuits are connected with the electric power supply circuit board. The electrical power saving circuit switches the state of functional circuits between the state in which they are provided with electric power and the state in which they are not provided with electric power. The electrical power saving circuit sets the contact point of the input side of the circuit, in which the consumption electrical current or the behavior guarantee minimum electrical voltage is the largest, out of the electrical power saving circuit and functional circuits provided with electric power, as the remote sensing location.

Abstract: A fuser control device includes: a fusing portion having a heater; a chopper portion including a reactor, a free-wheeling element, and a switching element; and a processor portion being configured to implement a first current control during an implementation period, the implementation period including a first time interval and a second time interval, the implementation period being longer than a commercial power period, the first current control for transferring a control signal having a predetermined duty ratio to the switching element during the first time interval and transferring a control signal having a 100% duty ratio to the switching element during the second time interval.

Abstract: A power control device receiving supply of power from a power source, the power control device including: a power accumulator accumulating a part of power from the power source; a first voltage converter receiving power from the power source and the power accumulator, performing voltage conversion to a first target voltage, and supplying power with the first target voltage to a first load; a second voltage converter receiving power from the first voltage converter, performing voltage conversion to a second target voltage, and supplying power with the second target voltage to a second load; a power source monitor monitoring power from the power source; and a power controller lowering the first target voltage to a level that the second voltage converter is capable of converting to the second target voltage when the power source monitor detects that the supply of power from the power source has stopped.

Abstract: A unit checking device is provided which checks whether a unit detachably provided to a device body is new or old. The unit checking device includes a transistor for checking provided in the unit and configured to be destructed by power supplied from the device body; and an inspection device provided in the device body and configured to determine whether or not the transistor is destructed by applying a voltage to the transistor.