# US 10,503,108 B2 · Power supply apparatus for outputting first and second voltages from one transformer and image forming apparatus including power supply apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,503,108 B2 - Document ID: US10503108B2 - Status: Granted - Kind: B2 - Application number: 16/052,434 - Filed: 2018-08-01 - Published: 2019-02-14 - Granted: 2019-12-10 - Earliest claimed: 2017-08-09 - Assignees: Canon Kabushiki Kaisha - Applicants: Canon Kabushiki Kaisha - Inventors: Junichi Kubota - Web page: https://patentgrep.com/patent/US10503108B2 ## CPC - G03G 15/5004: {Power supply control, e.g. power-saving mode, automatic power turn-off} - G03G 15/0283: {Arrangements for supplying power to the sensitising device} - G03G 15/1675: {with means for controlling the bias applied in the transfer nip} - G03G 15/168: {with means for conditioning the transfer element, e.g. cleaning} - G03G 15/80: {Details relating to power supplies, circuits boards, electrical connections} - H02M 3/335: using semiconductor devices only - G03G: ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY - H02M: APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF (transformers H01F; dynamo-electric converters H02K47/00; controlling transformers, reactors or choke coils, control or regulation of electric motors, generators or dynamo-electric converters H02P) ## Abstract A power supply apparatus including a transformer, a first rectifier smoothing unit, a separation unit, a second rectifier smoothing unit, a resistor, and a rectifier unit. The first rectifier smoothing unit is configured to rectify and smooth an alternating-current voltage generated in a secondary coil of the transformer. The separation unit configured to use the alternating-current voltage generated in the secondary coil of the transformer as an input and generate an alternating-current voltage, from which alternating-current components are separated, as an output. The second rectifier smoothing unit is configured to rectify and smooth the output of the separation unit. The resistor is connected to a line branched from a line that connects the separation unit to the second rectifier smoothing unit. The rectifier unit is connected in series between the resistor and a reference potential. ## Claims ### Claim 1 A power supply apparatus comprising: a one transformer having a primary coil and a secondary coil; a first rectifier smoothing unit configured to rectify and smooth an alternating-current voltage generated in the secondary coil of the transformer and output a first voltage; a separation unit configured to receive the alternating-current voltage generated in the secondary coil of the transformer as an input and generate an alternating-current voltage, from which alternating-current components are separated, as an output; a second rectifier smoothing unit configured to rectify and smooth the output of the separation unit and output a second voltage having a polarity opposite to a polarity of the first voltage; a resistor connected to a line branched from a line that connects the separation unit to the second rectifier smoothing unit; and a rectifier unit connected in series between the resistor and a reference potential. ### Claim 2 (depends on 1) The power supply apparatus according to claim 1, wherein the rectifier unit causes a current to flow in a direction from the separation unit towards the reference potential and interrupts a current flowing from the reference potential towards the separation unit. ### Claim 3 (depends on 1) The power supply apparatus according to claim 1, wherein a resistance value of the resistor is a resistance value at which a magnitude relationship between a first current value of a first current flowing by the separation unit when the voltage generated in the secondary coil is positive and a second current value of a second current flowing by the separation unit when the voltage generated in the secondary coil is negative becomes opposite to a magnitude relationship between a time when the first current flows and a time when the second current flows. ### Claim 4 (depends on 1) The power supply apparatus according to claim 1, wherein the rectifier unit includes a transistor, the power supply apparatus further comprising a control unit configured to perform switching control of the transistor in a manner that a current flows in the resistor for a time in accordance with a peak of the second voltage generated in the secondary coil. ### Claim 5 (depends on 4) The power supply apparatus according to claim 4, wherein the control unit performs the switching control of the transistor in a manner that, in a case where the peak of the negative voltage of the secondary coil declines, the time when the current flows is shortened as compared with the time before the peak declines. ### Claim 6 (depends on 1) The power supply apparatus according to claim 1, wherein the rectifier unit is a diode or a transistor. ### Claim 7 (depends on 1) The power supply apparatus according to claim 1, wherein the separation unit is a capacitor. ### Claim 8 An image forming apparatus comprising: an image bearing body having a surface on which a toner image is formed; first and second process members acting on the image bearing body; and a power supply apparatus configured to output a voltage to the first and second process members, the power supply apparatus including a one transformer having a primary coil and a secondary coil, and a first rectifier smoothing unit configured to rectify and smooth an alternating-current voltage generated in the secondary coil of the transformer, a first voltage output from the first rectifier smoothing unit being supplied to the first process member, a separation unit configured to receive the alternating-current voltage generated in the secondary coil of the transformer as an input and generate an alternating-current voltage, from which alternating-current components are separated, as an output, a second rectifier smoothing unit configured to rectify and smooth the output of the separation unit, a second voltage having a polarity opposite to a polarity of the first voltage and output from the second rectifier smoothing unit being supplied to the second process member, a resistor connected to a line branched from a line that connects the separation unit to the second rectifier smoothing unit, and a rectifier unit connected in series between the resistor and a reference potential. ### Claim 9 (depends on 8) The image forming apparatus according to claim 8, wherein the first process member includes a transfer member configured to transfer an image formed on the image bearing body to a recording material, and wherein the second process member includes a charging member configured to charge the image bearing body. ### Claim 10 (depends on 8) The image forming apparatus according to claim 8, wherein the rectifier unit causes a current to flow in a direction from the separation unit towards the reference potential and interrupts a current from the reference potential towards the separation unit. ### Claim 11 (depends on 8) The image forming apparatus according to claim 8, wherein a resistance value of the resistor is a resistance value at which a magnitude relationship between a first current value of a first current flowing by the separation unit when the voltage generated in the secondary coil is positive and a second current value of a second current flowing by the separation unit when the voltage generated in the secondary coil is negative becomes opposite to a magnitude relationship between a time when the first current flows and a time when the second current flows. ### Claim 12 (depends on 8) The image forming apparatus according to claim 8, wherein the rectifier unit includes a transistor, the image forming apparatus further comprising a control unit configured to perform switching control of the transistor in a manner that the current flows for a time in accordance with a peak of a negative voltage generated in the secondary coil. ### Claim 13 (depends on 12) The image forming apparatus according to claim 12, wherein the control unit performs the switching control of the transistor in a manner that, in a case where the peak of the negative voltage of the secondary coil declines, the time when the current flows is shortened as compared with the time before the peak declines. ### Claim 14 (depends on 8) The image forming apparatus according to claim 8, wherein the rectifier unit is a diode or a transistor. ### Claim 15 (depends on 8) The image forming apparatus according to claim 8, wherein the separation unit is a capacitor. ### Claim 16 (depends on 1) The power supply apparatus according to claim 1, wherein the first voltage is a positive voltage and the second voltage is a negative voltage. ### Claim 17 (depends on 1) The power supply apparatus according to claim 1, wherein the second rectifier smoothing unit prevents a current from flowing in the resistor in a case where the second rectifier smoothing unit is outputting the second voltage.