# US 2013/0156459 A1 · Power supply and image forming apparatus equipped with power supply > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2013/0156459 A1 - Document ID: US20130156459A1 - Status: Published application - Kind: A1 - Application number: 13/712,453 - Filed: 2012-12-12 - Published: 2013-06-20 - Earliest claimed: 2011-12-16 - Assignees: Canon Kabushiki Kaisha - Inventors: Jun Kawakatsu - Web page: https://patentgrep.com/patent/US20130156459A1 ## CPC - H02M 3/33507: {with automatic control of the output voltage or current, e.g. flyback converters (H02M3/33561, H02M3/33569 take precedence)} - H02M 1/10: Arrangements incorporating converting means for enabling loads to be operated at will from different kinds of power supplies, e.g. from AC or DC - 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 includes a rectification unit configured to be able to switch a rectification method between a voltage doubler rectification method and a full-wave rectification method according to an input alternating voltage, two capacitive elements serially connected between lines from the rectification unit, a monitoring unit configured to monitor a first voltage applied between the lines between which the two capacitive elements are connected and a second voltage applied across one of the capacitive elements that is connected to a lower potential side of the lines, and a switch configured to operate according to the second voltage, wherein the power supply interrupts the alternating voltage according to an operating state of the switch, the first voltage, and the second voltage. ## Claims ### Claim 1 A power supply, comprising: a rectification unit configured to be able to switch a rectification method between a voltage doubler rectification method and a full-wave rectification method according to an input alternating voltage; two capacitive elements serially connected between lines from the rectification unit; a monitoring unit configured to monitor a first voltage applied between the lines between which the two capacitive elements are connected and a second voltage applied across one of the capacitive elements that is connected to a lower potential side of the lines; and a switch configured to operate according to the second voltage, wherein the power supply interrupts the alternating voltage according to an operating state of the switch, the first voltage, and the second voltage. ### Claim 2 (depends on 1) The power supply according to claim 1, wherein, in a case where an overvoltage is applied across both of the capacitive elements or in a case where an overvoltage is applied to the capacitive element connected to the lower potential side, the switch operates to interrupt the alternating voltage when the second voltage exceeds a first threshold. ### Claim 3 (depends on 2) The power supply according to claim 2, wherein, in a case where an overvoltage is applied to another of the capacitive elements that is connected to a higher potential side of the lines, the power supply interrupts the alternating voltage when the first voltage exceeds a second threshold. ### Claim 4 (depends on 1) The power supply according to claim 1, wherein the monitoring unit includes a plurality of resistor elements configured to detect the second voltage, and wherein the switch operates according to the second voltage detected by the plurality of resistor elements. ### Claim 5 (depends on 1) The power supply according to claim 1, wherein, when an abnormality occurs in switching of the rectification unit, the power supply interrupts the alternating voltage according to the operating state of the switch, the first voltage, and the second voltage. ### Claim 6 An image forming apparatus, comprising: an image forming unit configured to form an image; and a power supply configured to supply power to the image forming unit, wherein the power supply comprises: a rectification unit configured to be able to switch a rectification method between a voltage doubler rectification method and a full-wave rectification method according to an input alternating voltage; two capacitive elements serially connected between lines from the rectification unit; a monitoring unit configured to monitor a first voltage applied between the lines between which the two capacitive elements are connected and a second voltage applied across one of the capacitive elements that is connected to a lower potential side of the lines; and a switch configured to operate according to the second voltage, and wherein the power supply interrupts the alternating voltage according to an operating state of the switch, the first voltage, and the second voltage. ### Claim 7 (depends on 6) The image forming apparatus according to claim 6, wherein, in a case where an overvoltage is applied across both of the two capacitive elements or in a case where an overvoltage is applied to the capacitive element connected to the lower potential side, the switch operates to interrupt the alternating voltage when the second voltage exceeds a first threshold. ### Claim 8 (depends on 7) The image forming apparatus according to claim 7, wherein, in a case where an overvoltage is applied to another of the capacitive elements that is connected to a higher potential side of the lines, the power supply interrupts the alternating voltage when the first voltage exceeds a second threshold. ### Claim 9 (depends on 6) The image forming apparatus according to claim 6, wherein the monitoring unit includes a plurality of resistor elements configured to detect the second voltage, and wherein the switch operates according to the second voltage detected by the plurality of resistor elements. ### Claim 10 (depends on 6) The image forming apparatus according to claim 6, wherein, when an abnormality occurs in switching of the rectification unit, the power supply interrupts the alternating voltage according to the operating state of the switch, the first voltage, and the second voltage. ### Claim 11 A power supply, comprising: a rectification unit configured to be able to switch a rectification method between a voltage doubler rectification method and a full-wave rectification method according to an input alternating voltage; a switching unit configured to switch the rectification method of the rectification unit; two capacitive elements serially connected between output lines from the rectification unit; and a monitoring unit configured to monitor a first voltage applied between the output lines between which the two capacitive elements are connected and a second voltage applied across one of the capacitive elements that is connected to a lower potential side of the lines, wherein the power supply interrupts the alternating voltage according to a monitored result obtained by the monitoring unit. ### Claim 12 An image forming apparatus, comprising: an image forming unit configured to form an image; and a power supply configured to supply power to the image forming unit, wherein the power supply comprises: a rectification unit configured to be able to switch a rectification method between a voltage doubler rectification method and a full-wave rectification method according to an input alternating voltage; a switching unit configured to switch the rectification method of the rectification unit; two capacitive elements serially connected between output lines from the rectification unit; and a monitoring unit configured to monitor a first voltage applied between the output lines between which the two capacitive elements are connected and a second voltage applied across one of the capacitive elements that is connected to a lower potential side of the lines, and wherein the power supply interrupts the alternating voltage according to a monitored result obtained by the monitoring unit.