# US 10,503,106 B2 · Image forming apparatus and image forming method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,503,106 B2 - Document ID: US10503106B2 - Status: Granted - Kind: B2 - Application number: 16/059,103 - Filed: 2018-08-09 - Published: 2019-02-21 - Granted: 2019-12-10 - Earliest claimed: 2017-08-17 - Assignees: Brother Kogyo Kabushiki Kaisha - Applicants: Brother Kogyo Kabushiki Kaisha - Inventors: Sadaharu Kato - Web page: https://patentgrep.com/patent/US10503106B2 ## CPC - G03G 15/2064: {combined with pressure} - G03G 15/0865: {Arrangements for supplying new developer} - G03G 15/2039: {with means for controlling the fixing temperature} - G03G 15/205: {specially for the mode of operation, e.g. standby, warming-up, error (G03G15/2046 takes precedence)} - G03G 15/2053: {Structural details of heat elements, e.g. structure of roller or belt, eddy current, induction heating} - G03G 15/6511: {Feeding devices for picking up or separation of copy sheets} - G03G: ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY ## Abstract An image forming apparatus includes: a heating member configured to heat a sheet; a heat source configured to heat the heating member; a temperature sensor configured to acquire a temperature of the heating member; a switching circuit configured to supply a current to the heat source by switching a voltage inputted from an alternating-current power source between an energization state and a non-energization state; and a controller. The controller executes: print processing of forming an image on the sheet; first energization processing of supplying the current to the heat source after a printing command is received and before the print processing is started; and second energization processing of setting a duty ratio of an output current of the switching circuit based on a detection result of the temperature sensor so that the heating member has a fixing temperature and supplying the current to the heat source, in the print processing. ## Claims ### Claim 1 An image forming apparatus, comprising: a heating member configured to fix a developer image on a sheet; a heat source configured to heat the heating member; a temperature sensor configured to acquire a temperature of the heating member; a switching circuit configured to supply a current to the heat source by switching a voltage inputted from an alternating-current power source between an energization state and a non-energization state; and a controller configured to execute: print processing of fixing the developer image on the sheet; first energization processing of supplying the current to the heat source after a printing command is received and before the print processing is started; and second energization processing of setting a duty ratio of an output current of the switching circuit based on a detection result of the temperature sensor so that the heating member has a fixing temperature and supplying the current to the heat source, in the print processing, wherein, in a case that the first energization processing is started, the controller is configured to set an energization pattern based on an end-time duty ratio, which is a duty ratio when the second energization processing last executed ends, and elapsed time, which has elapsed after the second energization processing last executed ends, and wherein the controller is configured to start the second energization processing, in a case that the controller has determined, after the first energization processing is executed and based on the detection result of the temperature sensor, that the heating member has a predefined temperature which is lower than the fixing temperature. ### Claim 2 (depends on 1) The image forming apparatus according to claim 1, wherein the controller is configured to set, as the end-time duty ratio, an average duty ratio in a predefined period immediately before the second energization processing ends. ### Claim 3 (depends on 1) The image forming apparatus according to claim 1, wherein, in the case that the first energization processing is started, the controller is configured to increase a duty ratio of the energization pattern as the end-time duty ratio increases. ### Claim 4 (depends on 1) The image forming apparatus according to claim 1, wherein, in the case that the first energization processing is started, and that a duty ratio of the energization pattern is set to less than 50%, the controller is configured to execute phase control. ### Claim 5 (depends on 1) The image forming apparatus according to claim 1, wherein, in the case that the first energization processing is started, and that a duty ratio of the energization pattern is set to equal to or more than 50%, the controller is configured to execute wavenumber control. ### Claim 6 (depends on 1) The image forming apparatus according to claim 1, wherein the heat source is a lamp having a filament and is configured to heat the heating member by radiant heat. ### Claim 7 (depends on 1) The image forming apparatus according to claim 1, wherein, in the case that the first energization processing is started, the controller is configured to make a duty ratio of the energization pattern larger as the elapsed time, which has elapsed after the second energization processing last executed ends. ### Claim 8 (depends on 7) The image forming apparatus according to claim 7, wherein, in a case that the elapsed time, which has elapsed after the second energization process last executed ends, is longer than a first period of time, the controller is configured to execute phase control, and in a case that the elapsed time, which has elapsed after the second energization process last executed ends, is equal to or shorter than the first period of time, the controller is last configured to execute wavenumber control. ### Claim 9 An image forming method using an image forming apparatus, the image forming apparatus comprising: a heating member configured to fix a developer image on a sheet; a heat source configured to heat the heating member; and a switching circuit configured to supply a current to the heat source by switching a voltage inputted from an alternating-current power source between an energization state and a non-energization state, the image forming method comprising: print processing of fixing the developer image on the sheet; first energization processing of supplying the current to the heat source after a printing command is received and before the print processing is started; and second energization processing of setting a duty ratio of an output current of the switching circuit based on a temperature of the heating member so that the heating member has a fixing temperature and supplying the current to the heat source, in the print processing, wherein, in a case that the first energization processing is started, an energization pattern is set based on an end-time duty ratio which is a duty ratio when the second energization processing last executed ends, and elapsed time, which has elapsed after the second energization processing last executed ends, and wherein the second energization processing is started, in a case that the heating member has a predefined temperature which is lower than the fixing temperature, after the first energization processing is executed. ### Claim 10 (depends on 9) The image forming method according to claim 9, wherein the end-time duty ratio is an average duty ratio in a predefined period immediately before the second energization processing is ended. ### Claim 11 (depends on 9) The image forming method according to claim 9, wherein, in the case that the first energization processing is started, a duty ratio of the energization pattern is made to be larger as the end-time duty ratio is larger. ### Claim 12 (depends on 9) The image forming method according to claim 9, wherein, in the case that first energization processing is started, and that a duty ratio of the energization pattern is set to less than 50%, phase control is executed. ### Claim 13 (depends on 9) The image forming method according to claim 9, wherein, in the case that first energization processing is started, and that a duty ratio of the energization pattern is set to equal to or more than 50%, wavenumber control is executed. ### Claim 14 (depends on 9) The image forming method according to claim 9, in the case that the first energization processing is started, a duty ratio of the energization pattern is made to be larger as the elapsed time, which has elapsed after the second energization processing last executed ends, is shorter. ### Claim 15 (depends on 14) The image forming method according to claim 14, wherein, in a case that the elapsed time, which has elapsed after the second energization processing last executed ends, is longer than a first period of time, phase control is executed, and in a case that the elapsed time, which has elapsed after the second energization process last executed ends, is equal to or shorter than the first period of time, wavenumber control is executed. ### Claim 16 An image forming apparatus, comprising: a heating member configured to fix a developer image on a sheet; a temperature sensor configured to acquire a temperature of the heating member; a heat source configured to heat the heating member; a switching circuit configured to supply a current to the heat source by switching a voltage inputted from an alternating-current power source between an energization state and a non-energization state; and a controller configured to execute: print processing of fixing the developer image on the sheet; first energization processing of supplying the current to the heat source after a printing command is received and before the print processing is started; and second energization processing of setting a duty ratio of an output current of the switching circuit based on a detection result of the temperature sensor so that the heating member has a fixing temperature and supplying the current to the heat source, in the print processing, wherein, in a case that the first energization processing is started, the controller is configured to set an energization pattern based on an end-time duty ratio, which is a duty ratio when the second energization processing last executed ends, and elapsed time, which has elapsed after the second energization processing last executed ends, wherein in the case that the first energization processing is started, in a case that the elapsed time, which has elapsed after the second energization process last executed ends, is longer than a first period of time, the controller is configured to execute phase control, and in a case that the elapsed time, which has elapsed after the second energization process last executed ends, is equal to or shorter than the first period of time, the controller is configured to execute wavenumber control, and in a case of executing the wavenumber control, the controller is configured to make the duty ratio of the energization pattern larger than a case of executing the phase control. ### Claim 17 (depends on 16) The image forming apparatus according to claim 16, wherein, in the case that the first energization processing is started, the controller is configured to make the first period of time longer as the end-time duty ratio increases. ### Claim 18 (depends on 17) The image forming apparatus according to claim 17, wherein in a case of executing the phase control, in a case that the elapsed time, which has elapsed after the second energization process last executed ends, is longer than a second period of time, the controller is configured to execute first phase control, and in a case that the elapsed time, which has elapsed after the second energization process last executed ends, is equal to or shorter than the first period of time and equal to or shorter than the second period of time, the controller is configured to execute second phase control, and wherein the controller is configured to make the duty ratio of the energization pattern larger than in a case of executing the phase control.