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 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 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: 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 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: 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 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.

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.

Abstract: The apparatus includes first and second terminals, an electrical conductor placed around at least the second terminal, a first current applying unit, an abnormal circumstances determining unit, a second current applying unit, and an informing unit. The first current applying unit applies current between the first terminal and the second terminal. The abnormal circumstances determining unit determines whether there is an abnormal circumstance at the connection between the apparatus and the unit side circuit, under the condition that the current is applied by the first current applying unit. The second current applying unit applies current between the first terminal and the second terminal, in case that the abnormal circumstances determining unit determined that there is not an abnormal circumstance of the connection.

Abstract: An electric power supply control device comprises a first converter, at least one second converter, and an electrical voltage control unit. The second converter can work in intermittent oscillation, and converts outputting electrical voltage from the first converter. The electrical voltage control unit controls the outputting electrical voltage of the first converter, so that the outputting electrical voltage is equal to or less than a minimum value of upper limits of operating electrical voltage of the second converter, and is more than or equal to a maximum value of lower limits of operating electrical voltage of the second converter, and at least one of the second converter performs low electric power behavior.

Abstract: An electric power supply control device comprises a first converter, at least one second converter, and an electrical voltage control unit. The second converter can work in intermittent oscillation, and converts outputting electrical voltage from the first converter. The electrical voltage control unit controls the outputting electrical voltage of the first converter, so that the outputting electrical voltage is equal to or less than a minimum value of upper limits of operating electrical voltage of the second converter, and is more than or equal to a maximum value of lower limits of operating electrical voltage of the second converter, and at least one of the second converter performs low electric power behavior.

Abstract: An image forming apparatus having image supporting members and developing devices provided for a plurality of colors respectively, and a developing bias source. The developing bias source includes DC power circuits provided for the colors respectively, an AC power circuit provided for use in common for all of the colors, and an element provided for at least one of the colors other than black. The developing bias source generates developing biases by superimposing an AC voltage output from the AC power circuit on DC voltages output from the DC power circuits and applies the developing biases to the respectively corresponding developing devices. The element maintains a constant voltage having a potential of an opposite polarity to a potential of charged toner used for the development. The developing bias source further superimposes the constant voltage on the developing bias for the at least one of the colors other than black.

Abstract: An image forming apparatus having image supporting members and developing devices provided for a plurality of colors respectively, and a developing bias source. The developing bias source includes DC power circuits provided for the colors respectively, an AC power circuit provided for use in common for all of the colors, and an element provided for at least one of the colors other than black. The developing bias source generates developing biases by superimposing an AC voltage output from the AC power circuit on DC voltages output from the DC power circuits and applies the developing biases to the respectively corresponding developing devices. The element maintains a constant voltage having a potential of an opposite polarity to a potential of charged toner used for the development. The developing bias source further superimposes the constant voltage on the developing bias for the at least one of the colors other than black.

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: The apparatus includes first and second terminals, an electrical conductor placed around at least the second terminal, a first current applying unit, an abnormal circumstances determining unit, a second current applying unit, and an informing unit. The first current applying unit applies current between the first terminal and the second terminal. The abnormal circumstances determining unit determines whether there is an abnormal circumstance at the connection between the apparatus and the unit side circuit, under the condition that the current is applied by the first current applying unit. The second current applying unit applies current between the first terminal and the second terminal, in case that the abnormal circumstances determining unit determined that there is not an abnormal circumstance of the connection.

Abstract: An image forming apparatus includes a plurality of heaters 56 for heating the fixing roller 52, a plurality of temperature sensors 57 for detecting the temperatures of the areas to be heated by the plurality of heaters 56 respectively, and a control unit 11 for turning on and off the plurality of heaters 56 on the basis of the temperatures detected by the plurality of temperature sensors 57. If one of the heaters 56 is on when the area to be heated by the other heater cools down to the ON temperature, the control unit 11 turns on the other heater with the same timing as the one heater is turned off.

Abstract: An image forming apparatus which allows a user to freely select a desired image quality is provided. The control unit 60 sets a of registration set value A1 for determining a color registration error suppression level and a dropout set value A2 for determining a dropout occurrence suppression level. Also, the control unit 60 sets a differential circumferential speed which is the difference between the circumferential speed of photoreceptor drums 1Y to 1K and the circumferential speed of an intermediate transfer belt 6 on the basis of the color registration set value A1 and the dropout set value A2. Then, the control unit 60 controls the belt drive motor 61 and the drum drive motor 62 on the basis of the differential circumferential speed which is set.