# US 9,436,150 B2 · Interlock mechanism in image forming apparatus and electrical device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,436,150 B2 - Document ID: US9436150B2 - Status: Granted - Kind: B2 - Application number: 14/809,148 - Filed: 2015-07-24 - Published: 2016-02-25 - Granted: 2016-09-06 - Earliest claimed: 2014-08-20 - Assignees: Canon Kabushiki Kaisha - Applicants: Canon Kabushiki Kaisha - Inventors: Takaomi Uezono - Web page: https://patentgrep.com/patent/US9436150B2 ## CPC - G03G 15/80: {Details relating to power supplies, circuits boards, electrical connections} - G03G 21/1633: {using doors or covers (G03G21/1638 takes precedence)} - G03G: ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY ## Abstract An opening and closing portion is opened and closed. A switch is turned off when a voltage applied to a drive terminal is smaller than a first voltage and to be turned on when the voltage is greater than or equal to a second voltage. A drive unit generates a drive voltage. A first line applies the drive voltage to the switch. A second line is arranged such that at least a part thereof is near the first line. A voltage drop element provided on the first line drops a voltage applied from the second line through the first line to the drive terminal when the first line and the second line short-circuit in a state where the portion is open, to lower the voltage applied to the drive terminal to be smaller than the first voltage. ## Claims ### Claim 1 An image forming apparatus comprising: an opening and closing portion configured to be capable of opening and closing; a switch configured to be turned off when a voltage applied to a drive terminal is smaller than a first voltage and to be turned on when the voltage applied to the drive terminal is greater than or equal to a second voltage that exceeds the first voltage; a drive unit configured to generate a drive voltage; a first line configured to be used to apply the drive voltage to the drive terminal of the switch; a second line arranged such that at least a part thereof is near the first line; and a voltage drop element provided on the first line and configured to drop the voltage applied to the drive terminal, wherein the voltage drop element drops a voltage applied from the second line through the first line to the drive terminal by a predetermined voltage when the first line and the second line short-circuit in a state where the opening and closing portion is open, so as to lower the voltage applied to the drive terminal to be smaller than the first voltage, thereby turning off the switch. ### Claim 2 (depends on 1) The image forming apparatus according to claim 1, wherein a difference between a drive voltage generated by the drive unit when the opening and closing portion is closed and the predetermined voltage is greater than or equal to the second voltage. ### Claim 3 (depends on 1) The image forming apparatus according to claim 1, wherein the opening and closing portion is a door that can be opened and closed by a user. ### Claim 4 (depends on 1) The image forming apparatus according to claim 1, wherein the switch is an electromagnetic relay. ### Claim 5 (depends on 1) The image forming apparatus according to claim 1, wherein the switch is a semiconductor switch. ### Claim 6 (depends on 1) The image forming apparatus according to claim 1, wherein the voltage drop element includes a diode. ### Claim 7 (depends on 6) The image forming apparatus according to claim 6, wherein the diode is a Zener diode. ### Claim 8 (depends on 6) The image forming apparatus according to claim 6, wherein a plurality of diodes are inserted on the first line, and the predetermined voltage includes a total value of forward voltages or breakdown voltages of the plurality of diodes. ### Claim 9 (depends on 1) The image forming apparatus according to claim 1, wherein the voltage drop element includes a resistor element. ### Claim 10 (depends on 1) The image forming apparatus according to claim 1, wherein the voltage drop element is provided on the first line between an interlock circuit that operates in accordance with opening/closing of the opening and closing portion and the switch. ### Claim 11 (depends on 1) The image forming apparatus according to claim 1, wherein the voltage drop element is provided on the first line between the switch and a grounding point. ### Claim 12 (depends on 1) The image forming apparatus according to claim 1, wherein the voltage drop element includes: an element provided on the first line between an interlock circuit that operates in accordance with opening/closing of the opening and closing portion and the switch; and an element provided on the first line between the switch and a grounding point. ### Claim 13 (depends on 12) The image forming apparatus according to claim 12, wherein the element provided between the switch and the grounding point is a transistor, a diode or a resistor element. ### Claim 14 (depends on 1) The image forming apparatus according to claim 1, wherein the second line is a wiring pattern for transmitting high level signals and low level signals output from a logical circuit or an integrated circuit, and a voltage applied from the second line through the first line to the drive terminal when the first line and the second line short-circuit in a state where the opening and closing portion is open is a high level voltage among voltages of signals output from the logical circuit or the integrated circuit. ### Claim 15 (depends on 1) The image forming apparatus according to claim 1, wherein the second line is a power supply line used for supplying an operating voltage to a logical circuit or an integrated circuit. ### Claim 16 (depends on 1) The image forming apparatus according to claim 1, wherein the switch is a switch that is provided on a power supply line used for supplying an alternating current to a load and switches between supplying and shutting off the alternating current. ### Claim 17 (depends on 16) The image forming apparatus according to claim 16, wherein the load is a fixing device configured to fix a toner image transferred to a sheet onto the sheet. ### Claim 18 (depends on 1) The image forming apparatus according to claim 1, wherein the switch is a switch that is provided on a power supply line used for supplying a direct current to a load and switches between supplying and shutting off the direct current. ### Claim 19 (depends on 18) The image forming apparatus according to claim 18, wherein the load is a motor.