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CN-117031901-B - Temperature control circuit and image forming apparatus

CN117031901BCN 117031901 BCN117031901 BCN 117031901BCN-117031901-B

Abstract

The application provides a temperature control circuit and an image forming device, and relates to the technical field of imaging. The temperature control circuit comprises a temperature detection circuit, a state comparison circuit, a first temperature protection circuit and a first switch circuit which are connected in sequence. Wherein the temperature detection circuit is operable to output the temperature detection value to the state comparison circuit. The state comparison circuit is used for comparing the temperature detection value with a preset temperature threshold value and outputting a first level signal to the first temperature protection circuit. The first temperature protection circuit can output a second level signal to the first switch circuit according to the first level signal and lock the second level signal in a target state. The first switch circuit is operable to switch to an off state in response to the second level signal. By the technical scheme, the heating can be controlled to stop when the heating temperature of the fixer is abnormal, and the fixing device is locked in a state of stopping heating, so that the reliability and the safety of the temperature control process are improved.

Inventors

  • LIU PENG
  • WANG GANG

Assignees

  • 珠海奔图电子有限公司

Dates

Publication Date
20260508
Application Date
20230810

Claims (9)

  1. 1. A temperature control circuit is characterized by comprising a temperature detection circuit, a state comparison circuit, a first temperature protection circuit and a first switch circuit which are connected in sequence; The temperature detection circuit is used for detecting the heating temperature of the heater and outputting a temperature detection value to the state comparison circuit; The state comparison circuit is used for comparing the temperature detection value with a preset temperature threshold value and outputting a first level signal associated with a comparison result to the first temperature protection circuit; the first temperature protection circuit is used for outputting a second level signal to the first switch circuit according to the first level signal and locking the second level signal in a target state; The first switch circuit is used for switching to an off state according to the second level signal; the first temperature protection circuit comprises a trigger circuit, a charge-discharge circuit, a choke circuit and a state locking circuit which are connected in sequence; the trigger circuit is used for triggering the charge-discharge circuit to enter a charging state according to the first level signal; And the charge-discharge circuit is used for triggering the state locking circuit to generate a second level signal and lock the second level signal in a target state after being charged to a target voltage, and triggering the choke circuit to prevent the voltage of the state locking circuit from flowing back.
  2. 2. The circuit of claim 1, wherein the state locking circuit is further configured to, after locking the second level signal in the target state, the trigger circuit: and triggering the charge-discharge circuit to enter a discharge state according to the first level signal.
  3. 3. The circuit of claim 1, wherein the first switching circuit comprises a relay.
  4. 4. The circuit of claim 1, further comprising a second temperature protection circuit and a second switching circuit; The state comparison circuit is further used for outputting the first level signal to the second temperature protection circuit; The second temperature protection circuit is used for generating a third level signal associated with the first level signal and outputting the third level signal to the second switch circuit; The second switching circuit is used for responding to the third level signal and switching to an off state.
  5. 5. The circuit of claim 4, wherein the second switching circuit comprises a thyristor.
  6. 6. The circuit of claim 4 or 5, further comprising a third temperature protection circuit and a control module; The state comparison circuit is further used for outputting the first level signal to the third temperature protection circuit; The third temperature protection circuit is used for generating a fourth level signal associated with the first level signal and outputting the fourth level signal to the control module; the control module is used for responding to the fourth level signal to control the first switching circuit and/or the second switching circuit to be switched to an off state.
  7. 7. The circuit of claim 1, wherein the circuit further comprises a power supply control circuit; the first temperature protection circuit is further used for outputting the second level signal to the power supply control circuit; The power supply control circuit is used for responding to the second level signal and cutting off the power supply.
  8. 8. The circuit of claim 7, wherein the power supply includes a first power supply for supplying power to the fuser and a second power supply for supplying power to the image forming device; The power supply control circuit is specifically configured to cut off the first power supply in response to the second level signal, or cut off the first power supply and the second power supply in response to the second level signal.
  9. 9. An image forming apparatus comprising the temperature control circuit according to any one of claims 1 to 8.

Description

Temperature control circuit and image forming apparatus [ Field of technology ] The present application relates to the field of imaging technologies, and in particular, to a temperature control circuit and an image forming apparatus. [ Background Art ] Image forming apparatuses such as printers and copiers include a fixing device having a heater for fixing a printing medium such as toner on a sheet of paper by heating, thereby completing image formation. In order to secure the safety of the heating process, it is necessary to detect and control the heating temperature of the fixer to control the fixer to stop heating in time when the temperature is abnormal. [ Invention ] The embodiment of the application provides a temperature control circuit and an image forming device, which can be used for controlling heating to stop when the heating temperature of a fixer is abnormal, and locking the heating stop state, so that the reliability and the safety of a temperature control process are improved. In a first aspect, an embodiment of the application provides a temperature control circuit, which comprises a temperature detection circuit, a state comparison circuit, a first temperature protection circuit and a first switch circuit which are sequentially connected, wherein the temperature detection circuit is used for detecting the heating temperature of a heater and outputting a temperature detection value to the state comparison circuit, the state comparison circuit is used for comparing the temperature detection value with a preset temperature threshold value and outputting a first level signal related to a comparison result to the first temperature protection circuit, the first temperature protection circuit is used for outputting a second level signal to the first switch circuit according to the first level signal and locking the second level signal in a target state, and the first switch circuit is used for responding to the second level signal to switch to an off state. In one possible implementation manner, the first temperature protection circuit comprises a trigger circuit, a charge-discharge circuit, a choke circuit and a state locking circuit which are connected in sequence, wherein the trigger circuit is used for triggering the charge-discharge circuit to enter a charging state according to the first level signal, the charge-discharge circuit is used for triggering the state locking circuit to generate a second level signal and lock the second level signal in a target state after being charged to the target voltage, and the choke circuit is triggered to prevent the voltage of the state locking circuit from flowing back. In one possible implementation manner, after the state locking circuit locks the second level signal in the target state, the triggering circuit is further configured to trigger the charge-discharge circuit to enter the discharge state according to the first level signal. In one possible implementation, the first switching circuit includes a relay. In one possible implementation manner, the circuit further comprises a second temperature protection circuit and a second switch circuit, wherein the state comparison circuit is further used for outputting the first level signal to the second temperature protection circuit, the second temperature protection circuit is used for generating a third level signal related to the first level signal and outputting the third level signal to the second switch circuit, and the second switch circuit is used for responding to the third level signal to switch to an off state. In one possible implementation, the second switching circuit includes a thyristor. In one possible implementation manner, the circuit further comprises a third temperature protection circuit and a control module, wherein the state comparison circuit is further used for outputting the first level signal to the third temperature protection circuit, the third temperature protection circuit is used for generating a fourth level signal associated with the first level signal and outputting the fourth level signal to the control module, and the control module is used for responding to the fourth level signal to control the first switch circuit and/or the second switch circuit to be switched to an off state. In one possible implementation manner, the circuit further comprises a power supply control circuit, the first temperature protection circuit is further used for outputting the second level signal to the power supply control circuit, and the power supply control circuit is used for responding to the second level signal and cutting off a power supply. In one possible implementation manner, the power supply includes a first power supply and a second power supply, where the first power supply is used to supply power to the fixer, the second power supply is used to supply power to the image forming apparatus, and the power supply control circuit is specifically configured to cut off the first