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 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: 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: An electric power supply control device comprises AC/DC converter, DC/DC converters, and an output electrical voltage monitor unit of the AC/DC converter. When output electrical voltage of the AC/DC converter increases to the first preset value P1, the AC/DC converter stops the convert. When the output electrical voltage decreases to the second preset value P2, the AC/DC converter restarts the convert. The first preset value P1 is equal to or less than the lowest value, out of the upper limit values in electrical voltage ranges in which the DC/DC converters CV1 and CV2 can work. The second preset value P2 is more than or equal to the highest value, out of the lower limit values in electrical voltage ranges in which the DC/DC converters CV1 and CV2 can work.

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 that forms a color image by overlaying toner images formed on respective first, second, and third photoreceptors, comprising: first, second, and third voltage-applied members respectively facing the first, second, and third photoreceptors; a first AC power supply generating first AC voltage, and superimposing the first AC voltage on first DC voltage to generate first voltage for causing a first electric field between the first voltage-applied member and the first photoreceptor; a second AC power supply generating second AC voltage, and superimposing the second AC voltage on second DC voltage to generate second voltage for causing a second electric field between the second voltage-applied member and the second photoreceptor; and a composite circuit superimposing a composite of the first voltage and the second voltage on third DC voltage, to generate third voltage for causing a third electric field between the third voltage-applied member and the third photoreceptor.

Abstract: A power supply device comprises: a rectifier circuit converting AC input voltage to DC; a smoothing capacitor connected to an output terminal of the rectifier circuit; a switching element turning on and off output from the smoothing capacitor to provide to a load; a switching controller controlling the switching of the switching element; a first signal input part generating a first signal for stopping the switching and keeping it stopped and inputting the first signal to the switching controller via a particular terminal thereof, when a trouble occurs on the power supply device; a detector detecting that the AC input voltage is a predetermined value or less; and a second signal input part generating a second signal for stopping the switching and keeping it stopped and inputting the second signal to the switching controller via the particular terminal, when the AC input voltage is the predetermined value or less.

Abstract: An image forming device includes a power source unit, motors supplied with and driven by electric power from the power source unit, and a control device for controlling the motors' operations. A CPU in the control device monitors presence/absence of power supply from the power source unit. When power is cut off during image forming, the CPU causes regenerative braking of the motors. The regenerated power is voltage-converted by a second DC-DC converter in the power source unit and supplied to the control device for continuously driving the CPU, which in turn backs up operating information. This eliminates inconsistency between the actual life status and the backed-up information when power is off, with no need of frequent backup during image forming. It is thus possible to provide the image forming device which can reliably manage operating information even if power supply to the motors is stopped during printing.

Abstract: An image forming apparatus that forms a color image by overlaying toner images formed on respective first, second, and third photoreceptors, comprising: first, second, and third voltage-applied members respectively facing the first, second, and third photoreceptors; a first AC power supply generating first AC voltage, and superimposing the first AC voltage on first DC voltage to generate first voltage for causing a first electric field between the first voltage-applied member and the first photoreceptor; a second AC power supply generating second AC voltage, and superimposing the second AC voltage on second DC voltage to generate second voltage for causing a second electric field between the second voltage-applied member and the second photoreceptor; and a composite circuit superimposing a composite of the first voltage and the second voltage on third DC voltage, to generate third voltage for causing a third electric field between the third voltage-applied member and the third photoreceptor.

Abstract: A power supply control device controls a power supply connected to a motor and includes: an AC/DC converter that makes a first DC power supply; a DC/DC converter that makes a second DC power supply out of the first DC power supply; a first rectifying element that allows current to flow from the first DC power supply toward the motor; a second rectifying element that allows current to flow from the first DC power supply toward the DC/DC converter; and a third rectifying element that allows current to flow from the motor toward the DC/DC converter. In this way, a power supply connected to a motor can be suitably controlled.

Abstract: A power supplying device provides power to the body of an image forming apparatus and an optional device connected to the body of the same. The power supplying device comprises: a rectifier circuit which rectifies an alternating current inputted from an alternating-current source; a booster circuit which boosts and smooths the direct-current voltage caused by the rectifier circuit; a judgment portion which judges whether or not there is an optional device connected to the body of the image forming apparatus; an identification portion which identifies the type of the optional device connected thereto; and a controller which, if there is an optional device connected thereto according to the judgment portion, adjusts the boosted voltage obtained by the booster circuit to a higher value than that if there is no optional device connected thereto, which depends on the type of the optional device identified by the identification portion.

Abstract: An image forming device includes a power source unit, motors supplied with and driven by electric power from the power source unit, and a control device for controlling the motors' operations. A CPU in the control device monitors presence/absence of power supply from the power source unit. When power is cut off during image forming, the CPU causes regenerative braking of the motors. The regenerated power is voltage-converted by a second DC-DC converter in the power source unit and supplied to the control device for continuously driving the CPU, which in turn backs up operating information. This eliminates inconsistency between the actual life status and the backed-up information when power is off, with no need of frequent backup during image forming. It is thus possible to provide the image forming device which can reliably manage operating information even if power supply to the motors is stopped during printing.

Abstract: A power supply control device controls a power supply connected to a motor and includes: an AC/DC converter that makes a first DC power supply; a DC/DC converter that makes a second DC power supply out of the first DC power supply; a first rectifying element that allows current to flow from the first DC power supply toward the motor; a second rectifying element that allows current to flow from the first DC power supply toward the DC/DC converter; and a third rectifying element that allows current to flow from the motor toward the DC/DC converter. In this way, a power supply connected to a motor can be suitably controlled.

Abstract: A power supply unit selects one of drive power provided from an AC/DC conversion unit and that provided from a separation unit and outputs the selected drive power to a control unit and a transmission and reception unit continuously. If the AC/DC conversion unit and the separation unit both supply their respective drive powers, the drive power that has a higher voltage value, i.e., the first drive power, is selectively output. When the first drive power supplied is stopped, a diode transitions from the on state to the off state and a diode transitions from the off state to the on state. As a result the second drive power is selectively output.

Abstract: This invention is related to a power supply unit used in an image forming apparatus having a induction heat fusing device. In the power supply unit, each of a first and a second rectifying circuits rectifies AC voltage from a power supply to generate DC voltage. An inverter circuit generates a high frequency voltage to be applied to a coil of the induction heat fusing device by switching the DC voltage from the first rectifying circuit. A switching circuit switches the DC voltage from said second rectifying circuit and generates AC voltage. A transformer receives the AC voltage from the switching circuit and outputs a transformed voltage to be apply to a component of the image forming apparatus. The inverter, second rectifying circuit and switching circuit are connected to a common ground line.