Abstract: An image forming apparatus is provided. The image forming apparatus includes a plurality of photosensitive members arranged to align in parallel with one another, an exposure device arranged in an upper position with respect to the plurality of photosensitive members and configured to expose the photosensitive members to light, an exposure controller arranged in an upper position with respect to the exposure device and configured to control the exposure device according to inputted image data, a power board, arranged in a lower position with respect to the plurality of photosensitive members and configured to convert alternate current power to direct current power, and a voltage converter arranged in an upper position with respect to the exposure device and configured to convert the direct current power supplied from the power board into an at least single-leveled first voltage and supply the first voltage to the exposure controller.

Abstract: An image forming apparatus includes execution units configured to execute predetermined functional processing, and switches to a second power state lower than a first power state. After a user selects priority on power saving or priority on convenience as a condition for switching to the second power state, the image forming apparatus receives a plurality of recovery triggers for switching to the first power state. A number of times of detection of each recovery trigger received is stored. If the user selects priority on convenience, it is determined whether the number of times of detection of each recovery trigger requiring a large power amount consumed by execution units associated with each recovery trigger falls below a predetermined threshold. If it is determined that the number of times of detection of a recovery trigger falls below the predetermined threshold, the recovery trigger may be disabled.

Abstract: A power supply device includes a first switch section that can disconnect a 24-V power supply from a commercial alternating-current (AC) power supply and that operates with the voltage of 3.3 V, and a second switch section that can disconnect a voltage detection circuit from the commercial AC power supply and that operates with the voltage of 3.3 V. When a power saving mode is on, the 24-V power supply and the voltage detection circuit are disconnected from the commercial AC power supply by using the first and second switch sections, whereby the power supply device can be used in areas where different supply voltages are used, and at the same time reduction in power consumption in the power saving mode is achieved.

Abstract: An image forming apparatus includes a fixing section, a low voltage detection circuit, an arithmetic control section, and a storage section. The fixing section has a heater and fixes a toner image on recording paper with heat of the heater. The low voltage detection circuit detects a drop in an input voltage from a power source. The arithmetic control section determines, when a drop in the input voltage is detected by the low voltage detection circuit, whether the drop in the input voltage is linked to working of the heater. The arithmetic control section lowers the temperature of the heater when the drop in the input voltage is linked to the working of the heater, and causes the storage section to store a result of the detection by the low voltage detection circuit when the drop in the input voltage is not linked to the working of the heater.

Abstract: The power supply apparatus includes a transformer having primary and secondary sides, a switching element, a feedback unit, a conversion unit that converts a current flowing in a primary winding of the transformer into a voltage, a control unit that controls operation of the switching element, a voltage switching unit that increases the voltage output from the conversion unit and feeds the increased voltage to the control unit when a continuous oscillation state is transited to an intermittent oscillation state. The voltage switching unit switches the voltage of the power supply that is input into the control unit to be higher when the continuous oscillation state is transited to the intermittent oscillation state.

Abstract: A power supply control device includes a monitoring controller, a moving body detector, and a power supply controller. The monitoring controller controls a processor, an interface part, and an identification information acquisition part. The moving body detector detects whether or not a moving body including a user who intends to use the processor exists within a specific region. The power supply controller individually allows objects to be controlled including the processor, the interface part, the identification information acquisition part, and the monitoring controller to enter a power supply state or a power interruption state in an independent manner, in accordance with detection information by the moving body detector, and first controls the identification information acquisition part to be shifted from the power interruption state to the power supply state in a case where all the objects to be controlled are in the power interruption state.

Abstract: A high-voltage power supply module includes a front-end power converting circuit, a first back-end circuit, a second back-end circuit, a ground terminal and a controlling unit. The front-end power converting circuit receives an input voltage and converts the input voltage into a bus voltage. The first back-end circuit receives the bus voltage and outputs a first voltage. The second back-end circuit receives the bus voltage and outputs a second voltage. The first back-end circuit and the second back-end circuit are connected with a connecting terminal. The ground terminal is connected with the connecting terminal. In response to the first voltage and the second voltage, a first control signal and a second control signal are respectively issued from the controlling unit to the first back-end circuit and the second back-end circuit, thereby adjusting the magnitudes of the first voltage and the second voltage.

Abstract: The power supply apparatus includes a transformer having primary and secondary sides, a switching element, a feedback unit, a conversion unit that converts a current flowing in a primary winding of the transformer into a voltage, a control unit that controls operation of the switching element, a voltage switching unit that increases the voltage output from the conversion unit and feeds the increased voltage to the control unit when a continuous oscillation state is transited to an intermittent oscillation state. The voltage switching unit switches the voltage of the power supply that is input into the control unit to be higher when the continuous oscillation state is transited to the intermittent oscillation state.

Abstract: An image forming apparatus includes a plurality of power generation units, a charge control unit, a charge switch unit, and a controller, Each of the plurality of power generation units is respectively provided to a corresponding one of a plurality of high-temperature portions in the image forming apparatus to generate power based on temperatures of the high-temperature portions. The charge control unit charges a power storage unit with electrical energy generated by the power generation units. The charge switch unit switches between the power generation units to connect one of the power generation units to the charge control unit. The controller controls the charge switch unit to selectively connect one of the power generation units capable of achieving a maximum power generation efficiency to the charge control unit.

Abstract: A high voltage power supply includes a developer carrier, an image carrier, a developing control unit, a load detection unit, a variation detection unit, and a voltage correction unit. The developing control unit applies a developing bias voltage to the developer carrier and thereby supplies the developer to the image carrier and develops an electrostatic latent image. The variation detection unit detects the variation in capacitance between the developer carrier and the image carrier detected by the load detection unit. The voltage correction unit corrects the developing bias voltage by decreasing the developing bias voltage as the variation increases, and increasing the developing bias voltage as the variation decreases.

Abstract: Disclosed is an image forming apparatus, including: a job input unit; a job execution unit; a job storing unit; a start-up cost calculation unit to calculate a start-up cost which is a cost for start-up of the image forming apparatus, when the job is input from the job input unit; a total sum calculation unit to calculate a total sum of investable amount of the input job and the stored jobs; a job control unit to instruct the job storing unit to store the input job in case that the total sum is less than the start-up cost, and instruct the job execution unit to collectively execute the input job and the stored jobs in case that the total sum is not less than the start-up cost; and a charging unit configured to allocate the start-up cost to the jobs, and charge the allocated start-up cost for each executed job.

Abstract: An image forming apparatus includes a switching unit configured to switch a power supply source from a main power source to a power storage unit according to shifting to a power failure state, a calculation unit configured to calculate a power amount to be consumed by a received job if the power supply source is the power storage unit when the job is received, a detection unit configured to detect a power amount stored in the power storage unit, a determining unit configured to determine whether the received job can be executed based on the detected power amount and the calculated power amount to be consumed for the received job, and a control unit configured to start processing the job if it is determined that the received job can be executed and to perform control during the processing of the job so as not to accept a subsequently received job.

Abstract: An image forming apparatus includes: an applying device configured to generate an output signal and apply the output signal to an image forming device; and a controller configured to generate a control signal to supply to the applying device so as to control a value of the output signal so that the value of the output signal is within a predetermined target range and control the applying device using the control signal in a start-up mode and in a normal mode, the normal mode being subsequent to the start-up mode. In the start-up mode, the controller sets a start control signal value larger than a value of the control signal immediately after a first predetermined time, the start control signal value being the value of the control signal during the first predetermined time, the first predetermined time being from a start timing of the start-up mode.

Abstract: An image forming apparatus includes a transfer unit configured to transfer a toner image onto a recording medium; a power supply unit configured to output one of an alternating-current-based voltage including at least an alternating-current voltage and a direct-current voltage to the transfer unit; and a power supply control unit configured to cause the power supply unit to start switching to the alternating-current-based voltage a first time after the power supply unit stops outputting the direct-current voltage in the case that output of the power supply unit is switched to the alternating-current-based voltage, and cause the power supply unit to start switching to the direct-current voltage a second time after the power supply unit stops outputting the alternating-current-based voltage in the case that output of the power supply unit is switched to the direct-current voltage. The second time is longer than the first time.

Abstract: A power control system includes an image forming apparatus, a power calculating unit, and a condition controller. The image forming apparatus operates using power, forms an image corresponding to image information in a first operation mode, and enters a second operation mode in which power consumption is smaller than the first operation mode when the image forming apparatus satisfies a specific transition condition. The power calculating unit calculates power supplied from a power supplying unit. The condition controller controls the specific transition condition for the image forming apparatus in accordance with the power calculated by the power calculating unit.

Abstract: A transfer device includes a direct-current (DC) power supply configured to output a DC voltage; an alternating-current (AC) power supply configured to selectively output a superimposed voltage in which an AC voltage is superimposed on the DC voltage output from the DC power supply or the DC voltage output from the DC power supply; and a transfer unit configured to transfer a developer to a sheet using the voltage output from the AC power supply.

Abstract: The heating apparatus includes a heat generating member which generates heat when power is supplied from an AC power supply, a temperature detection device which detects temperature of the heat generating member, a current detection device which detects a value of current flowing in the heat generating member; and a control unit which controls the temperature of the heat generating member by controlling power supplied to the heat generating member, in which the control unit detects a drop of an input voltage of the AC power supply based on a maximum suppliable power ratio determined by using a value of current suppliable to the heat generating member, the current value detected by the current detection device, and a ratio of power supplied to the heat generating member obtained based on the temperature detected by the temperature detection device.

Abstract: A conveying apparatus or an image forming apparatus includes: a housing including an opening and closing member that can be opened and closed; a conveying path that conveys an object to be conveyed, at least a part of the conveying path being provided adjacent to an inner side of the opening and closing member; a first detector that detects whether the object is present in a predetermined region and outputs a detection signal corresponding to a result of the detection; and an interlocking mechanism that causes, when the opening and closing member is opened, the first detector to change at least one of a position and a structure of the first detector in mechanically association with movement of opening of the opening and closing member, and to output a detection signal which is the same as a detection signal output when the object is present in the predetermined region.

Abstract: A method of controlling a data processing apparatus including: a drive system device; a data processing device configured to perform data processing; and a power supply circuit configured to generate a drive system voltage to be supplied to the drive system device and a data processing system voltage to be supplied to the data processing device, from an input voltage from an external power supply. The method comprises: when an interruption of the input voltage is detected, switching an operation mode to a power saving mode in which the drive system device is stopped or restrained from driving, and then executing a protective operation for the data processing device.

Abstract: An image forming apparatus includes an image carrier and the following elements. A charging unit generates a charging electric field and charges the image carrier with the charging electric field. An exposure unit exposes the charged image carrier to light and forms an electrostatic latent image on the image carrier. A developing unit generates a developing electric field and develops the electrostatic latent image. A transfer unit transfers the developed image onto a transfer subject. At least one of the charging electric field and the developing electric field is generated by a bias power supply unit including a transformer having a primary winding and a secondary winding, and also including the following elements. A switch circuit supplies a current to the primary winding of the transformer by switching a switching device. A modulator circuit generates a PWM modulation signal. A waveform setting unit sets a waveform of a carrier signal.

Abstract: In a power supply device, the controller outputs a control signal specifying a voltage value. The voltage conversion unit converts a first voltage to a second voltage in response to a control signal specifying a voltage value output from the controller. The voltage conversion unit converts the first voltage to a start voltage, as the second voltage, in response to a first control signal specifying a start voltage value output from the controller and further converts the first voltage to a target voltage, as the second voltage, in response to a second control signal specifying a target voltage value output from the controller. A transition period of time is intervened between generation of the start voltage and generation of the target voltage during which the controller outputs a third control signal specifying the intermediate voltage value between the start voltage value and the target voltage value.

Abstract: An image forming apparatus includes an image carrier and the following elements. A charging unit charges the image carrier. An exposure unit exposes the charged image carrier to light and forms an electrostatic latent image. A developing unit generates a developing electric field and develops the electrostatic latent image. A transfer unit transfers the developed image. A controller outputs an AC setting signal. The developing unit includes a bias power supply source having the following elements. An output transformer includes a primary winding and a secondary winding. A switching circuit supplies a current to the primary winding. A current control circuit includes first impedance and second impedance. The first impedance is set when the AC voltage has a first frequency and the second impedance is set when the AC voltage has a second frequency, thereby controlling a current flowing between the primary winding and the switching circuit.

Abstract: An image forming apparatus includes an image carrier, a charging unit, an exposure unit, a developing unit, and a transfer unit. The transfer unit includes a bias power supply and transfers a developed image onto a transfer body. The bias power supply includes a first power supply unit, a second power supply unit, a threshold setting unit, a detector, and an output controller. The first power supply unit generates a transfer electric field. The second power supply unit generates a non-transfer electric field. The threshold setting unit has a first threshold and a second threshold, and performs a change from the first threshold to the second threshold when switching from the non-transfer electric field to the transfer electric field is performed. The detector detects the current which is caused to flow by the first power supply unit. The output controller controls the first power supply unit.

Abstract: A high voltage power source device includes piezoelectric transformers, each of the piezoelectric transformers being formed with a primary electrode and a secondary electrode on piezoelectric ceramics, receiving a primary voltage at the primary electrode, and generating a second voltage from the secondary electrode, switching elements, each of the switching elements driving a respective one of the piezoelectric transformers, and primary voltage supply devices, each of the primary voltage supply devices supplying the primary voltage to the primary electrode of the respective one of the piezoelectric transformers by driving the respective one of the switching elements when the secondary voltage is generated from the respective one of the second electrodes, wherein the respective one of the primary voltage supply devices supplies the primary voltage to the respective one of the primary electrodes by driving the respective one of the switching elements at the same frequency.

Abstract: A power supply apparatus capable of outputting a predetermined voltage or a predetermined electrical current selectively is provided, including a voltage level setter to determine an output level of a voltage or an electrical current according to an external signal, a constant voltage feedback unit to correct an output value of the voltage level setter so as to output a constant voltage of the output level to a load terminal, a constant current feedback unit to maintain the external signal constantly and correct an output value of the voltage level setter so as to output a constant current of the output level to the load terminal, a switch to connect the voltage level setter with the constant voltage feedback unit or the constant current feedback unit selectively, and a controller to control the switch to output the constant voltage or the constant current selectively according to a state of the load terminal.

Abstract: An image forming apparatus includes: an image bearing member for bearing a toner image; a belt for transferring the toner image from the image bearing member onto a transfer material; an electric power supplying device, contacted to the belt, to which a voltage is to be applied, wherein the electric power supplying device includes an erected fiber portion formed with a plurality of electroconductive erected fibers contacted to the belt; a power source; and a contact member, connected to the electric power supplying device, for applying the voltage from the power source to the electric power supplying device. The electric power supplying device includes a welded portion formed by heat aggregation of a part of the erected fiber portion, and the contact member is connected to the welded portion.

Abstract: The discharge circuit includes plural resistors connected in parallel to a capacitor and connected between input lines. When input of an alternative voltage has stopped, the plural resistors form plural discharge paths to remove charges accumulated in the capacitor, thereby removing the charges in the capacitor connected between the input lines of the alternative voltage.

Abstract: In an image-forming apparatus including: an image forming unit which forms an unfixed toner image on a recording material; a fixing unit having a heat generating member which generates heat by power supplied from a commercial AC power source via a choke coil, the fixing unit heating the unfixed toner image formed by the image forming unit and thereby fixing the image to the recording material; and a control unit which controls the supply of power from the commercial AC power source to the heat generating member. The control unit supplies power to the heat generating member by control including phase control, during printing for performing an image forming operation by the image forming unit, and supplies power to the heat generating member by wave number control during standby for awaiting a print instruction.

Abstract: Systems and methods receive user feedback during user interaction with at least one printing apparatus to record user annoyance measurements for one or more users into memory of at least one computerized device. The systems and methods automatically calculate one or more user annoyance curves for the users from the user annoyance measurements. The annoyance curves relate to one or more performance characteristics of the printing apparatus. The systems and methods automatically select a specific annoyance curve from the annoyance curves depending upon which of the users is utilizing the printing apparatus. The systems and methods automatically determine a performance characteristic level for the printing apparatus that will maintain user annoyance below a predetermined standard for each of the users using the specific annoyance curve for each user. The systems and methods automatically set components of the printing apparatus to operate so as to achieve the identified performance characteristic level.

Abstract: An image processing apparatus that is operable by AC power and DC power. The image processing apparatus includes a fixing heater section for heating a recording sheet having toner transferred thereon so as to fuse the toner onto the sheet and a plurality of electronic circuits. An AC power supply circuit section receives AC power from an AC power supply line. A DC power supply circuit section receives DC power from a DC power supply line. A power supply unit supplies the AC power received by the AC power supply circuit section to the fixing heater section, and the DC power received by the DC power supply circuit section to the plurality of electronic circuits.

Abstract: A processing apparatus that an uninterruptible power supply system supplies power to and carries out a process. The processing apparatus includes an electric energy amount determination part that determines, based on a charged amount of electric energy in the uninterruptible power supply system, an amount of maximum electric energy that the uninterruptible power supply system can supply; and a function selection part that selects, depending on the amount of maximum electric energy, functions that can be used for carrying out the process.

Abstract: A constant current-type high-voltage power supply apparatus which is used in an image forming apparatus includes a leakage current detection unit that detects a leakage current leaked from at least one output terminal of the constant current-type high-voltage power supply apparatus and outputs the detected leakage current, a direct current voltage output unit that outputs different direct current (DC) voltages according to whether the leakage current detected by the leakage current detection unit is input, and a power control unit that controls power supply to the constant current-type high-voltage power supply apparatus according to the output DC voltage.

Abstract: An image forming apparatus and a power control method thereof, the power control method of an image forming apparatus which includes a finisher to perform at least one of finishing jobs including arranging, sorting, grouping, folding, stapling, binding, and punching a print medium which is ejected after an image is formed thereon, the power control method including: determining whether or not a power mode of the image forming apparatus meets requirements for entering a power save mode in which power supplied to a part of elements of the image forming apparatus is shut off; determining whether or not the image forming apparatus has an ongoing job if the requirements for entering the power save mode are met; and entering the image forming apparatus in the power save mode while the power supply to the finisher is maintained if the image forming apparatus has the ongoing job.

Abstract: A power supply device includes: a power supply part to convert an AC voltage from an AC power source into a direct current and output a DC voltage; a zero cross detector to detect zero cross timings of AC voltage; and a power supply controller to control supply of the AC voltage to the power supply part and the zero cross detector based on the zero cross timing.

Abstract: An image forming apparatus includes a receiving unit configured to receive an input regarding a print process from a user; a setting unit configured to set the apparatus to normal or energy saving mode based on the input from the user, the normal mode causing the apparatus to be operated by the power supplied from a power supply unit, the energy saving mode causing the apparatus to be operated by the power supplied from the power supply unit or a secondary battery so that power consumption of the apparatus is less than that in the normal mode; a calculation unit configured to calculate a charging amount of the battery based on an energy saving time for which the apparatus has been in the energy saving mode; and a charging unit configured to charge the battery with the power from the power supply unit by the charging amount.

Abstract: The image forming apparatus includes a fixing section which has a heater and heats and fixes an unfixed image, formed on a recording material, to the recording material, a power supply section which has a rectification section rectifying alternating current, a power factor improvement section receiving input of current output from the rectification section, and a DC/DC converter DC/DC converting current output from the power factor improvement section, a current detection section which detects current flowing to the heater, and a control section which controls operation of the power factor improvement section according to current detected by the current detection section.

Abstract: The power supply device includes a transformer, a switching unit for driving a primary side of the transformer, a detection unit for detecting an output corresponding to a current flowing on the primary side, a transmission unit for transmitting an output voltage from a secondary side to the primary side, and a control unit for controlling an operation of the switching unit in accordance with an output from the transmission unit, in which, when a switching frequency for driving the switching unit falls within a predetermined frequency range including a resonant frequency of the transformer, the control unit controls the switching unit so as to shorten a turn-ON time of the switching unit in accordance with an output from the detection unit.

Abstract: Disclosed is a power supply including a first voltage generating unit that generates a first voltage from an external power supply; a second voltage generating unit that generates a first predetermined voltage and supplies the generated first predetermined voltage to the load; a third voltage generating unit that generates the first predetermined voltage and supplies the generated first predetermined voltage to the load; and a controller that causes the first voltage to be greater than or equal to a second voltage during a first mode, and causes the first voltage to be less than the second voltage during a second mode. During the first mode, the power is supplied from the second voltage generating unit and the third voltage generating unit to the load, and during the second mode, the power is supplied from the third voltage generating unit to the load.

Abstract: A high-voltage power supply device includes: a piezoelectric transformer; a driving unit of the piezoelectric transformer; a detection unit configured to detect an output of the piezoelectric transformer; and a control unit configured to control the output of the piezoelectric transformer by giving a driving signal to the driving unit so that the output detected by the detection unit reaches a target value, wherein the control unit changes a frequency of the driving signal without changing a duty of the driving signal so as to set the frequency of the driving signal such that the output detected by the detection unit falls within a predetermined range including the target value, and after setting the frequency for the driving signal such that the output detected by the detection unit falls within the predetermined range, changes the duty of the driving signal so that the output detected by the detection unit reaches the target value.

Abstract: An image-forming apparatus is provided which enables more productive image formation. When an option unit implements a change from a second operation mode that exhibits high power consumption to a first operation mode that exhibits low power consumption while images are being consecutively formed on a plurality of recording materials, an upper limit on power that can be supplied to a fixing section is set higher than that in the second operation mode, and intervals, at which recording materials are consecutively fed, are set narrower than those in the second operation mode.

Abstract: A printing apparatus comprising a storage unit having a driving unit, determines whether or not access to the storage device is required with reception of data; determines whether or not a predetermined period of time has elapsed after transition to a first operation state; in a case where the predetermined period of time has elapsed, obtains, as an estimation time, a period of time until next reception of data that requires access to the storage device based on history information; and causes the printing apparatus to transition from the first operation state to a second operation state in a case where the estimation time exceeds a threshold of a period of time decided based on an amount of power consumption for when the driving unit is driven, and maintain the printing apparatus in the first operation state in a case where the estimation time does not exceed the threshold.

Abstract: A printing apparatus having a printing engine, a first control unit, and a second control unit, in which a normal operation is performed by at least the printing engine and the first control unit, a first power saving operation is performed by at least the first control unit while the printing engine is stopped, and a second power saving operation is performed by only the second control unit, the printing apparatus including: a first storage unit of the first control unit that stores a setting value reflecting a setting change performed while the printing apparatus is operated and an operation value not reflecting the setting change performed while the printing apparatus is operated; a second storage unit of the second control unit that stores the setting value and the operation value.

Abstract: An image forming apparatus capable of accurately computing power consumption thereof. First power consumption consumed by a fixing device of the image forming apparatus until the fixing device becomes a state capable of fixing a toner image onto a sheet is computed, second power consumption that includes power consumption consumed by the fixing device to fix the toner image onto the sheet and power consumption consumed by conveyance of the sheet is computed according to at least a sheet type, and third power consumption consumed by an exposure unit of the image forming apparatus to expose a photosensitive member of the image forming apparatus to light is computed according to an image to be formed. Then, a sum of the first to third power consumptions is computed.

Abstract: A switching power supply includes a transformer, a switching unit configured to switch a voltage input to the primary side of the transformer, a control unit configured to control the operation of the switching unit, and a detection unit configured to detect as a voltage a current flowing through the primary side of the transformer and supply the voltage to the control unit, wherein the detection unit controls the voltage to be supplied to the control unit based on the operating state of the switching unit.

Abstract: A negative bias circuit outputs a DC voltage of a negative polarity. A positive bias circuit outputs a DC voltage of a positive polarity. The DC voltage of the positive polarity is used, for example, as a transfer voltage, and the DC voltage of the negative polarity is used as a cleaning voltage for cleaning toner. A cycle of the clock signal in a period during which the DC voltage of the first polarity is output is longer than a cycle of the clock signal in the period during which the voltage supplied to the load transits from the DC voltage of the first polarity to the DC voltage of the first polarity.

Abstract: A piezoelectric transducer driver configured to drive a piezoelectric transducer for converting an inputted alternating-current voltage, includes: a drive circuit configured to generate the alternating-current voltage to be inputted into the piezoelectric transducer; a frequency controller configured to control a frequency of the alternating-current voltage as a drive frequency to be applied to the piezoelectric transducer; and a pulse generation circuit configured to generate a drive pulse having a switching frequency corresponding to the drive frequency, and to output the drive pulse to the drive circuit. The drive circuit includes a switching element configured to generate the alternating-current voltage by executing a switching operation corresponding to a pulse width of the drive pulse, and the pulse generation circuit changes the pulse width depending on the switching frequency.

Abstract: An apparatus includes a CPU, wherein, when the apparatus is currently in a power OFF state, and if an operation different from that of a power source switch is performed, the CPU connects a load to a power source by the switch to discharge a capacitor.

Abstract: A power-supply device includes: a rectifier circuit configured to output a rectified voltage by rectifying an output from a transformer; a comparator circuit configured to compare a comparison voltage corresponding to an output voltage or an output current that are generated based on the rectified voltage with the indicator voltage and to control an operation of the transformer drive circuit so as to reduce the difference between the comparison voltage and the indicator voltage; a constant voltage element configured to limit the output voltage or the output current by operating as a constant voltage source when the value of the output voltage or the output current reaches a threshold; and a current mirror circuit. The current mirror circuit is configured to lower the indicator voltage by allowing a current proportional to the current flowing through the constant voltage element to flow through the current path.

Abstract: An image forming apparatus includes a power supply unit to generate DC power, a plurality of function units to perform the functions of the image forming apparatus, a control unit to control the operation of a plurality of function units, a switching unit to receive DC power of the power supply unit and switch power provided to the control unit and each of a plurality of function units, and a power management unit to receive DC power of the power supply unit and to control a switching operation of the switching unit according to an operation mode of the image forming apparatus.

Abstract: A power supply system includes: capacitors connected to an alternating current power supply; a rectification circuit connected to the capacitors and rectifying an alternating current voltage applied to the capacitors; a signal generation circuit connected to an output line of the rectification circuit and configured to generate a detection signal corresponding to a zero cross point of an alternating current output; an electricity storage unit connected to the output line of the rectification circuit; a backflow regulation element provided on the output line of the rectification circuit and configured to regulate backflow of current; a current limit element configured to limit current flowing from the output line of the rectification circuit towards the electricity storage unit, and a control unit that is connected to the output line of the rectification circuit, and is configured to detect a zero cross point of the alternating current output.