High-voltage output control circuit and laser printing equipment with same

Abstract

The invention relates to the technical field of laser printing, and discloses a high-voltage output control circuit and laser printing equipment with the high-voltage output control circuit, the high-voltage output control circuit comprises a self-excited oscillation unit, a starting control unit, a peak value detection unit, an output rectification unit and a controller, the starting control unit responds to a control signal output by the controller, and the peak value detection unit detects the peak value of the self-excited oscillation unit; the self-excited oscillation unit is controlled to start for oscillation work; the self-oscillation unit is used for carrying out oscillation coupling on the first direct current and carrying out rectification through the output rectification unit so as to output a second direct current; the peak detection unit is used for detecting the peak voltage of the self-excited oscillation unit so as to output a voltage detection signal to the controller; and the controller is used for enabling the starting control unit to control the self-oscillation unit to recover normal oscillation work by adjusting parameters of the control signal under the condition that the self-oscillation unit is determined to be abnormal according to the voltage detection signal, so that the condition that the machine is not controlled is avoided, and the safe and reliable operation of the machine is ensured.

Description

Technical Field

[0001] This application relates to the field of laser printing technology, and in particular to a high-voltage output control circuit for a laser printing device and a laser printing device having the high-voltage output control circuit. Background Technology

[0002] In laser printing machines such as printers or copiers, a high-voltage output is typically required to achieve electrostatic transfer, such as a positive or negative voltage ranging from hundreds to tens of thousands of volts. This high-voltage power supply is generally obtained by first converting AC mains power into DC 24V using an AC / DC converter, and then using a self-excited oscillation method to convert the DC 24V DC power into a high-voltage output. Furthermore, the DC 24V DC power is further converted into a lower voltage, such as DC 5V, by a DC / DC converter to provide low-voltage power to the system.

[0003] However, if the aforementioned high-voltage power supply is not protected and controlled in a timely and effective manner during the operation of the laser printer, it will not only affect the normal operation of the machine, but may even damage the machine and cause inconvenience to the user. Summary of the Invention

[0004] The purpose of this application is to provide a high-voltage output control circuit for a laser printing device and a laser printing device having the high-voltage output control circuit. When the self-excited oscillation unit is oscillating, the circuit detects the peak voltage of the self-excited oscillation unit to determine whether the self-excited oscillation unit is malfunctioning. If the self-excited oscillation unit is malfunctioning, the circuit adjusts the parameters of the control signal that starts the self-excited oscillation unit to enable the self-excited oscillation unit to resume normal oscillation operation, thereby preventing the machine from becoming uncontrollable, ensuring the safe and reliable operation of the machine, extending the machine's service life, and improving the user experience.

[0005] To achieve the above objectives, the main technical solutions adopted in this application include: In a first aspect, embodiments of this application provide a high-voltage output control circuit for a laser printing device, comprising: a self-excited oscillation unit, a start-up control unit, a peak detection unit, an output rectification unit, and a controller. The start-up control unit, in response to a control signal output by the controller, controls the self-excited oscillation unit to start oscillation operation. The self-excited oscillation unit is used to oscillate and couple an input first DC current, and rectify it through the output rectification unit to output a second DC current, the voltage of which is greater than the voltage of the first DC current. The peak detection unit is used to detect the peak voltage of the self-excited oscillation unit during operation and output a voltage detection signal to the controller. The controller, when determining from the voltage detection signal that the self-excited oscillation unit is malfunctioning, adjusts the parameters of the control signal to allow the start-up control unit to control the self-excited oscillation unit to resume normal oscillation operation.

[0006] According to the high-voltage output control circuit of the laser printing equipment provided in the embodiments of this application, the start control unit responds to the control signal output by the controller to control the self-excited oscillation unit to start oscillation. In this way, the self-excited oscillation unit achieves high-voltage output by oscillating and coupling the first input DC power and rectifying it through the output rectifier unit. When the self-excited oscillation unit is working, the peak voltage of the self-excited oscillation unit is detected by the peak detection unit and the voltage detection signal is output to the controller. Thus, if the controller determines that the self-excited oscillation unit is abnormal based on the voltage detection signal, it can adjust the parameters of the control signal so that the start control unit can control the self-excited oscillation unit to resume normal oscillation, thereby avoiding uncontrolled machine operation, ensuring safe and reliable machine operation, extending machine life and improving user experience.

[0007] Optionally, in some embodiments of this application, the controller is further configured to increase at least one of the duty cycle and amplitude of the control signal when it is determined from the voltage detection signal that the self-excited oscillation unit has no peak voltage, and to determine that the self-excited oscillation unit has resumed normal oscillation operation when the peak voltage of the self-excited oscillation unit is detected by the peak detection unit.

[0008] Optionally, in some embodiments of this application, the controller is further configured to, when adjusting the duty cycle and amplitude of the control signal to their respective maximum values, determine that the self-excited oscillation unit still has no peak voltage based on the voltage detection signal, and control the laser printing equipment to stop working.

[0009] Optionally, in some embodiments of this application, the controller is further configured to, when it is determined from the voltage detection signal that the peak voltage of the self-excited oscillation unit exceeds a preset voltage range, reduce at least one of the duty cycle and amplitude of the control signal, and determine that the self-excited oscillation unit has returned to a controlled state when the peak voltage of the self-excited oscillation unit is detected by the peak detection unit to be within the preset voltage range.

[0010] Optionally, in some embodiments of this application, the controller is further configured to determine that the self-excited oscillation unit has run out of control and control the laser printing equipment to stop working if the peak voltage of the self-excited oscillation unit still exceeds the preset voltage range when the duty cycle and amplitude of the control signal are adjusted to the corresponding minimum values.

[0011] Optionally, in some embodiments of this application, the peak detection unit includes: a first transient suppression diode, the cathode of which is connected to the primary winding of the self-excited oscillation unit; a first resistor, one end of which is connected to the anode of the first transient suppression diode; a second resistor, one end of which is connected to the other end of the first resistor and has a first node, the other end of which is grounded, and the first node serves as the output terminal of the peak detection unit; and a first capacitor, which is connected in parallel with the second resistor.

[0012] Optionally, in some embodiments of this application, the self-excited oscillation unit includes: a transformer, the transformer including a primary main winding, a primary oscillation winding and a secondary winding, the same-name terminal of the primary main winding being adapted to be connected to the first DC power, and the opposite-name terminal of the primary main winding being connected to the cathode of the first transient suppression diode; a transistor, the collector of the transistor being connected to the opposite-name terminal of the primary main winding, the emitter of the transistor being grounded, the base of the transistor being connected to the same-name terminal of the primary oscillation winding, and the opposite-name terminal of the primary oscillation winding being connected to the starting control unit.

[0013] Optionally, in some embodiments of this application, the starting control unit includes: a third resistor, one end of which is adapted to receive a control signal output by the controller; a fourth resistor, one end of which is connected to the other end of the third resistor and has a second node, the other end of which is adapted to connect to a preset power supply; a second transient suppression diode, the cathode of which is connected to the second node and the anode of which is grounded; a second capacitor, which is connected in parallel with the second transient suppression diode; a fifth resistor, one end of which is connected to the second node; an operational amplifier, the positive input terminal of which is connected to the other end of the fifth resistor; a sixth resistor, one end of which is adapted to connect to a preset power supply; and a seventh resistor, one end of which is connected to the other end of the sixth resistor. A seventh resistor is connected to the third node, and has a third node. The other end of the seventh resistor is connected to the negative input terminal of the operational amplifier. An eighth resistor is connected to the third node at one end and grounded at the other end. The third node is suitable for receiving a high-voltage output feedback voltage. A ninth resistor is connected to the output terminal of the operational amplifier at one end. A third transient suppression diode is connected to the cathode of the third transient suppression diode at the other end. A third capacitor is connected to the anode of the third transient suppression diode at one end and has a fourth node. The other end of the third capacitor is grounded. A tenth resistor is connected in parallel with the third transient suppression diode. An eleventh resistor is connected to the fourth node at one end and to the opposite terminal of the primary oscillation winding at the other end.

[0014] Optionally, in some embodiments of this application, the output rectifier unit includes: a first diode, the anode of which is connected to the opposite terminal of the secondary winding; a second diode, the cathode of which is connected to the opposite terminal of the secondary winding; a fourth capacitor, one end of which is connected to the cathode of the first diode and serves as the output terminal of the output rectifier unit, and the other end of which is connected to the same terminal of the secondary winding; and a fifth capacitor, one end of which is connected to the same terminal of the secondary winding, and after being connected to the anode of the second diode, the fifth capacitor is connected to a reference ground.

[0015] Secondly, embodiments of this application provide a laser printing device, including: a high-voltage output control circuit for the laser printing device described in the above embodiments.

[0016] According to the laser printing equipment provided in the embodiments of this application, based on the high-voltage output control circuit described in the above embodiments, when the self-excited oscillation unit is oscillating, it can detect the peak voltage of the self-excited oscillation unit to determine whether the self-excited oscillation unit is abnormal. If the self-excited oscillation unit is abnormal, it can adjust the parameters of the control signal that controls the self-excited oscillation unit to start, so that the self-excited oscillation unit can resume normal oscillation operation, avoid the machine from becoming uncontrollable, ensure the safe and reliable operation of the machine, improve the service life of the machine and enhance the user experience. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0018] Figure 1 A block diagram of a high-voltage output control circuit for a laser printing device provided in one embodiment of this application; Figure 2 A circuit diagram of a high-voltage output control circuit for a laser printing device provided in one embodiment of this application; Figure 3 This is a schematic diagram illustrating the linear relationship between the output high voltage of the output rectifier unit and the PWM signal, provided in one embodiment of this application. Figure 4 A to Figure 4 C is a schematic diagram showing the voltage change under different states detected by a peak detection unit provided in an embodiment of this application; Figure 5 A schematic diagram showing the peak voltage of the self-excited oscillation unit in different states according to an embodiment of this application; Figure 6 This is a block diagram of a laser printing device provided in one embodiment of this application. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0020] In related technologies, laser printing machines, such as printers or copiers, generally use a self-excited oscillation method to convert DC24V direct current into high voltage output to provide high voltage power. However, in some cases, the self-excited oscillation circuit may fail to oscillate, resulting in no high voltage output. Alternatively, in some cases, the self-excited oscillation circuit may become uncontrollable, resulting in abnormally high high voltage output and damaging the machine.

[0021] Therefore, the high-voltage output control circuit of the laser printing equipment and the laser printing equipment having the high-voltage output control circuit provided in this application embodiment determine whether the self-excited oscillation unit is abnormal by detecting the peak voltage of the self-excited oscillation unit when the self-excited oscillation unit is oscillating. If the self-excited oscillation unit is abnormal, the parameters of the control signal that controls the self-excited oscillation unit to start are adjusted so that the self-excited oscillation unit can resume normal oscillation operation, avoid the machine from becoming uncontrollable, ensure the safe and reliable operation of the machine, improve the service life of the machine and enhance the user experience.

[0022] The high-voltage output control circuit of the laser printing device provided in this application and the laser printing device having the high-voltage output control circuit will now be described in detail with reference to the accompanying drawings.

[0023] refer to Figure 1 The diagram shown is a block illustration of a high-voltage output control circuit for a laser printing device according to an embodiment of this application. Figure 1 As shown, the high-voltage output control circuit of the laser printing equipment includes a self-excited oscillation unit 10, a start-up control unit 20, a peak detection unit 30, an output rectification unit 40, and a controller 50. The start-up control unit 20 is connected to the controller 50, for example, a system SoC. In response to the control signal output by the controller 50, such as a PWM signal, the start-up control unit 10 is activated to oscillate. The self-excited oscillation unit 10 is used to oscillate and couple the first input DC power, such as DC24V, and rectify it through the output rectification unit 40 to output a second DC power, such as a high-voltage DC power of several hundred volts to tens of thousands of volts. The voltage of the second DC power is greater than the voltage of the first DC power. Furthermore, the peak detection unit 30 is used to detect the peak voltage of the self-excited oscillation unit 10 when it is working, and outputs a voltage detection signal to the controller 50. The controller 50 is used to adjust the parameters of the control signal when it is determined that the self-excited oscillation unit 10 is abnormal according to the voltage detection signal, so that the start control unit 20 controls the self-excited oscillation unit 10 to resume normal oscillation operation, so as to avoid the machine from becoming uncontrollable and ensure the safe and reliable operation of the machine.

[0024] Furthermore, such as Figure 2As shown, when the control signal output by the controller 50 is zero, the output of the start control unit 20 is zero, and the self-excited oscillation unit 10 does not start. When the controller 50 outputs a control signal, such as a PWM signal, to the start control unit 20, under the control of the PWM signal, when the start control unit 20 outputs a high level, the self-excited oscillation unit 10 starts and performs oscillation coupling. The output rectifier unit 40 starts high-voltage output. The start control unit 20 adjusts the voltage output to the self-excited oscillation unit 10 according to the feedback voltage of the high-voltage output to achieve stability. The self-excited oscillation unit 10 also enters a stable oscillation state, and the high-voltage output of the output rectifier unit 40 also remains stable. During this process, the peak detection unit 30 detects the peak voltage of the self-excited oscillation unit 10 and sends the detected voltage detection signal to the controller 50. The controller 50 then determines whether the self-excited oscillation unit 10 is malfunctioning. If the self-excited oscillation unit 10 is malfunctioning, the controller can adjust the parameters of the control signal, such as the PWM signal, that starts the self-excited oscillation unit 10, so that the self-excited oscillation unit 10 can resume normal oscillation operation. This prevents the machine from becoming uncontrollable, ensures the safe and reliable operation of the machine, extends the machine's lifespan, and improves the user experience.

[0025] Among them, such as Figure 3 As shown, the high voltage output of the output rectifier unit 40 and the parameters of the PWM signal, such as the duty cycle or voltage, can be configured to have a linear proportional relationship. That is, the larger the duty cycle or voltage of the PWM signal, the larger the output voltage of the output rectifier unit 40. In this way, by adjusting the parameters of the PWM signal, the oscillation state of the self-excited oscillation unit 10 can be adjusted, thereby adjusting the high voltage output of the output rectifier unit 40.

[0026] Specifically, in one embodiment of this application, such as Figure 2 As shown, the peak detection unit 30 includes a first transient suppression diode TVS1, a first resistor R1, a second resistor R2, and a first capacitor C1. The cathode of the first transient suppression diode TVS1 is connected to the opposite terminal of the primary winding of the self-excited oscillation unit 10. One end of the first resistor R1 is connected to the anode of the first transient suppression diode TVS1. One end of the second resistor R2 is connected to the other end of the first resistor R1 and has a first node. The other end of the second resistor R2 is grounded. The first node serves as the output terminal of the peak detection unit 30, and outputs a voltage detection signal to the controller 50. The first capacitor C1 is connected in parallel with the second resistor R2.

[0027] In this embodiment, the peak detection voltage 30, by setting the first transient suppression diode TVS1, can accurately detect the peak voltage of the self-excited oscillation unit 10, and at the same time can also play the role of protecting the circuit. The first capacitor C1 plays the role of filtering and voltage regulation.

[0028] Optionally, in some embodiments of this application, such as Figure 2 As shown, the self-excited oscillation unit 10 includes a transformer TR1 and a transistor Q1. The transformer TR1 includes a primary main winding N1, a primary oscillation winding N2, and a secondary winding N3. The same-name terminal of the primary main winding N1 is adapted to be connected to a first DC power supply, such as DC24V. The opposite-name terminal of the primary main winding N1 is connected to the cathode of the first transient suppression diode TVS1. The collector of the transistor Q1 is connected to the opposite-name terminal of the primary main winding N1. The emitter of the transistor Q1 is grounded. The base of the transistor Q1 is connected to the same-name terminal of the primary oscillation winding N2. The opposite-name terminal of the primary oscillation winding N2 is connected to the starting control unit 20.

[0029] Furthermore, the starting control unit 20 includes a third resistor R3, a fourth resistor R4, a second transient suppression diode TVS2, a second capacitor C2, a fifth resistor R5, an operational amplifier 201, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, a third transient suppression diode TVS3, a third capacitor C3, an eleventh resistor R11, a twelfth resistor R12, and a sixth capacitor C6. One end of the third resistor R3 is suitable for connecting a control signal, such as a PWM signal, output by the controller 50. One end of the fourth resistor R4 is connected to the other end of the third resistor R3 and has a second node. The other end of the fourth resistor R4 is suitable for connecting a preset power supply, such as DC 5V. The cathode of the second transient suppression diode TVS2 is connected to the second node, and the anode of the second transient suppression diode TVS2 is grounded. The second capacitor C2 is connected in parallel with the second transient suppression diode TVS2. One end of the fifth resistor R5 is connected to the second node, and the positive input terminal of the operational amplifier 201 is connected to the other end of the fifth resistor R5. One end of the sixth resistor R6 is suitable for connecting a preset power supply, such as DC 5V. One end of the seventh resistor R7 is connected to the other end of the sixth resistor R6 and has a third node. The other end of the seventh resistor R7 is connected to the operational amplifier 201. The negative input terminal of the first resistor is connected to the second resistor. One end of the eighth resistor R8 is connected to the third node, and the other end of the eighth resistor R8 is grounded. The third node is suitable for connecting the high-voltage output feedback voltage VFB. The twelfth resistor R12 and the sixth capacitor C6 are connected in series between the negative input terminal and the output terminal of the operational amplifier 201. One end of the ninth resistor R9 is connected to the output terminal of the operational amplifier 201. The cathode of the third transient suppression diode TVS3 is connected to the other end of the ninth resistor R9. One end of the third capacitor C3 is connected to the anode of the third transient suppression diode TVS3 and has a fourth node. The other end of the third capacitor C3 is grounded. The tenth resistor R10 is connected in parallel with the third transient suppression diode TVS3. One end of the eleventh resistor R11 is connected to the fourth node, and the other end of the eleventh resistor R11 is connected to the opposite terminal of the primary oscillation winding N2.

[0030] Optionally, in one embodiment of this application, such as Figure 2As shown, the output rectifier unit 40 includes a first diode D1, a second diode D2, a fourth capacitor C4, and a fifth capacitor C5. The anode of the first diode D1 is connected to the opposite terminal of the secondary winding N3. The cathode of the second diode D2 is connected to the opposite terminal of the secondary winding N3. One end of the fourth capacitor C4 is connected to the cathode of the first diode D1 and serves as the output terminal of the output rectifier unit 40. The other end of the fourth capacitor C4 is connected to the same terminal of the secondary winding N3. One end of the fifth capacitor C5 is connected to the same terminal of the secondary winding N3. After the fifth capacitor C5 is connected to the anode of the second diode D2, it is connected to the reference ground.

[0031] In this embodiment, the output rectifier unit 40 uses a voltage doubler rectification method to achieve high voltage output.

[0032] Specifically, when the PWM input voltage is zero, the voltage V- at the negative input terminal of operational amplifier 201 is greater than the voltage V+ at the positive input terminal, the output of operational amplifier 201 is zero, and the self-oscillation unit 10 does not start. When the controller 50 outputs a PWM signal to the start control unit 20, the PWM signal is converted into a voltage signal through the integrator circuit in the start control unit 20. At this time, the voltage at the positive input terminal of operational amplifier 201 increases, and the voltage at the negative input terminal of operational amplifier 201 is less than the voltage at the positive input terminal. The output of operational amplifier 201 is high level. After restoration processing, the high-level signal is output to the self-oscillation unit 10, the loop of the self-oscillation unit 10 starts, and the high voltage begins to be output. The output voltage is fed back to the negative input terminal of operational amplifier 201 through the sampling resistor, causing the voltage at the negative input terminal of operational amplifier 201 to increase until it is the same as the voltage at the positive input terminal. At this time, the output of operational amplifier 201 reaches stability, the loop oscillation of the self-oscillation unit 10 also reaches stability, and the output voltage remains stable.

[0033] In other words, PWM input → positive input voltage V+ increases → op-amp outputs high level (voltage gradually increases) → self-oscillating circuit starts (oscillation gradually increases) → high voltage output voltage increases → negative input voltage V- increases → V- and V+ voltages equalize → circuit reaches stability. Therefore, it can be seen that the higher the duty cycle or voltage of the PWM input, the larger the high voltage output. This can be designed as a linear proportional relationship, such as... Figure 3 As shown.

[0034] Therefore, in the embodiments of this application, after the self-excited oscillation circuit is started, the peak detection unit 30 detects the collector voltage of the transistor Q1 (used to characterize the peak voltage of the self-excited oscillation unit 10) to determine whether the self-excited oscillation circuit is abnormal.

[0035] Furthermore, in one embodiment of this application, the controller 50 is also configured to increase at least one of the duty cycle and amplitude of the control signal, such as the PWM signal, when it is determined from the voltage detection signal that the self-excited oscillation unit 10 has no peak voltage, and determine that the self-excited oscillation unit 10 has resumed normal oscillation operation when the peak voltage of the self-excited oscillation unit 10 is detected by the peak detection unit 30.

[0036] In other words, if the controller 50 outputs a PWM signal, but the peak detection unit 30 does not detect the peak voltage, it can be determined that the self-oscillation unit has not started. Figure 4 A and Figure 5 As shown. At this time, the controller 50 can first provide a PWM signal with a higher duty cycle or increase the amplitude of the PWM signal, for example, to the maximum value (because a higher voltage amplitude or a higher duty cycle makes it easier for the circuit to start). Then, the peak voltage is detected again. If a peak voltage is detected, it is determined that the circuit of the self-excited oscillation unit 10 has started, such as... Figure 4 B and Figure 5 As shown, the self-excited oscillation unit 10 resumes normal operation, and then adjusts the PWM signal back to the set target, ensuring that the output reaches the expected set value while the circuit starts.

[0037] Furthermore, the controller 50 is also used to determine that the self-excited oscillation unit 10 has an oscillation failure when the duty cycle and amplitude of the control signal, such as the PWM signal, are adjusted to their respective maximum values, and if the self-excited oscillation unit 10 still has no peak voltage according to the voltage detection signal, then control the laser printing equipment to stop working.

[0038] In other words, if the controller 50 adjusts the duty cycle and amplitude of the PWM signal to their maximum values, and the peak detection unit 30 still does not detect the peak voltage, it indicates that the circuit of the self-excited oscillation unit 10 has failed, the machine cannot work normally, the laser printing equipment will stop working, and an alarm will be issued.

[0039] Optionally, in another embodiment of this application, the controller 50 is further configured to, when it is determined from the voltage detection signal that the peak voltage of the self-excited oscillation unit 10 exceeds the preset voltage range, reduce at least one of the duty cycle and amplitude of the control signal, such as the PWM signal, and determine that the self-excited oscillation unit 10 has returned to the controlled state when the peak voltage of the self-excited oscillation unit 10 is detected by the peak detection unit 30 to be within the preset voltage range.

[0040] In other words, if the controller 50 outputs a PWM signal and the peak voltage detected by the peak detection unit 30 exceeds a certain range, it can be determined that the circuit of the self-excited oscillation unit 10 has become uncontrolled. Figure 4 C and Figure 5As shown, the self-excited oscillation unit 10 reaches its maximum output after the circuit starts oscillating. At this time, the controller 50 can lower the duty cycle of the PWM signal or lower the amplitude of the PWM signal to zero, and then detect the peak voltage again. If the peak voltage returns to the normal range, such as... Figure 4 B and Figure 5 As shown, the self-excited oscillation unit 10 resumes normal operation, and then adjusts the PWM signal back to the set target, ensuring that the output reaches the expected set value while the circuit starts.

[0041] Furthermore, the controller 50 is also used to determine that the self-excited oscillation unit 10 has run out of control fault when the duty cycle and amplitude of the control signal, such as the PWM signal, are adjusted to the corresponding minimum values, and if the peak voltage of the self-excited oscillation unit 10 still exceeds the preset voltage range, and to control the laser printing equipment to stop working.

[0042] In other words, if the controller 50 adjusts the duty cycle and amplitude of the PWM signal to the minimum value, such as zero, and the peak detection unit 30 still detects the peak voltage at the maximum output, it indicates that the circuit of the self-excited oscillation unit 10 is out of control, resulting in a circuit out-of-control fault, which may damage the machine. It is necessary to control the laser printing equipment to stop working and issue an alarm prompt.

[0043] Therefore, in the embodiments of this application, after the controller 50 outputs a PWM signal to control the self-excited oscillation unit 10 to start through the start control unit 20, the peak voltage of the self-excited oscillation unit 10 is detected by the peak detection unit 30, and the peak voltage detection result is combined to comprehensively determine whether the self-excited oscillation unit 10 has an abnormal start-up or an uncontrolled abnormality. Once an abnormality occurs, the duty cycle and / or amplitude of the PWM signal are adjusted to restore the self-excited oscillation unit 10 to normal. When the self-excited oscillation unit 10 cannot restore normal operation, the machine can also be stopped in time to ensure the safe and reliable operation of the machine.

[0044] In summary, according to the high-voltage output control circuit of the laser printing equipment provided in this application embodiment, the start control unit 20 responds to the control signal output by the controller 50 to control the self-excited oscillation unit 10 to start oscillation. In this way, the self-excited oscillation unit 10 achieves high-voltage output by oscillating and coupling the input first DC power and rectifying it through the output rectifier unit 40. When the self-excited oscillation unit 10 is working, the peak voltage of the self-excited oscillation unit 10 is detected by the peak detection unit 30, and a voltage detection signal is output to the controller 50. Thus, if the controller 50 determines that the self-excited oscillation unit 10 is abnormal based on the voltage detection signal, it can adjust the parameters of the control signal so that the start control unit 20 can control the self-excited oscillation unit 10 to resume normal oscillation, thereby avoiding uncontrolled machine operation, ensuring safe and reliable machine operation, improving machine lifespan and enhancing user experience.

[0045] In addition, such as Figure 6 As shown, this application embodiment also provides a laser printing device 200, which includes the high-voltage output control circuit 100 of the laser printing device described in the above embodiment.

[0046] According to the laser printing equipment 200 provided in the embodiments of this application, based on the high-voltage output control circuit 100 described in the above embodiments, when the self-excited oscillation unit is oscillating, it can detect the peak voltage of the self-excited oscillation unit to determine whether the self-excited oscillation unit is abnormal. If the self-excited oscillation unit is abnormal, it can adjust the parameters of the control signal that controls the self-excited oscillation unit to start, so that the self-excited oscillation unit can resume normal oscillation operation, avoid the machine from becoming uncontrollable, ensure the safe and reliable operation of the machine, improve the service life of the machine and improve the user experience.

[0047] In the description of this specification, the terms "one embodiment," "some embodiments," "embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0048] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make modifications, alterations, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A high-voltage output control circuit for a laser printing device, characterized in that, include: The system comprises a self-excited oscillation unit, a start-up control unit, a peak detection unit, an output rectification unit, and a controller. The starting control unit, in response to the control signal output by the controller, controls the self-excited oscillation unit to start oscillation operation; The self-excited oscillation unit is used to oscillate and couple the input first DC current, and rectify it through the output rectifier unit to output a second DC current, the voltage of the second DC current being greater than the voltage of the first DC current; The peak detection unit is used to detect the peak voltage of the self-excited oscillation unit when the self-excited oscillation unit is working, and to output a voltage detection signal to the controller. The controller is used to adjust the parameters of the control signal when it is determined from the voltage detection signal that the self-excited oscillation unit is malfunctioning, so that the starting control unit can control the self-excited oscillation unit to resume normal oscillation operation.

2. The high-voltage output control circuit of the laser printing equipment according to claim 1, characterized in that, The controller is further configured to, when it is determined from the voltage detection signal that the self-excited oscillation unit has no peak voltage, increase at least one of the duty cycle and amplitude of the control signal, and when the peak voltage of the self-excited oscillation unit is detected by the peak detection unit, determine that the self-excited oscillation unit has resumed normal oscillation operation.

3. The high-voltage output control circuit of the laser printing equipment according to claim 2, characterized in that, The controller is further configured to, when adjusting the duty cycle and amplitude of the control signal to their respective maximum values, determine that the self-excited oscillation unit still has no peak voltage based on the voltage detection signal, and control the laser printing equipment to stop working.

4. The high-voltage output control circuit of the laser printing equipment according to claim 1, characterized in that, The controller is further configured to, when determining that the peak voltage of the self-excited oscillation unit exceeds the preset voltage range based on the voltage detection signal, reduce at least one of the duty cycle and amplitude of the control signal, and determine that the self-excited oscillation unit has returned to a controlled state when the peak voltage of the self-excited oscillation unit is detected to be within the preset voltage range by the peak detection unit.

5. The high-voltage output control circuit of the laser printing equipment according to claim 4, characterized in that, The controller is also configured to determine that the self-excited oscillation unit has malfunctioned and control the laser printing equipment to stop working if the peak voltage of the self-excited oscillation unit still exceeds the preset voltage range when the duty cycle and amplitude of the control signal are adjusted to the corresponding minimum values.

6. The high-voltage output control circuit of the laser printing equipment according to any one of claims 1-5, characterized in that, The peak detection unit includes: A first transient suppression diode, the cathode of which is connected to the primary winding of the self-excited oscillation unit; A first resistor, one end of which is connected to the anode of the first transient suppression diode; The second resistor has one end connected to the other end of the first resistor and has a first node. The other end of the second resistor is grounded, and the first node serves as the output terminal of the peak detection unit. The first capacitor is connected in parallel with the second resistor.

7. The high-voltage output control circuit of the laser printing equipment according to claim 6, characterized in that, The self-excited oscillation unit includes: The transformer includes a primary main winding, a primary oscillating winding, and a secondary winding. The same-name terminal of the primary main winding is adapted to be connected to the first DC power supply, and the opposite-name terminal of the primary main winding is connected to the cathode of the first transient suppression diode. The transistor has its collector connected to the opposite terminal of the primary main winding, its emitter grounded, its base connected to the same terminal of the primary oscillation winding, and its opposite terminal connected to the starting control unit.

8. The high-voltage output control circuit of the laser printing equipment according to claim 7, characterized in that, The starting control unit includes: A third resistor, one end of which is adapted to be connected to the control signal output by the controller; A fourth resistor, one end of which is connected to the other end of the third resistor and has a second node, the other end of which is adapted to be connected to a preset power supply; The second transient suppression diode has its cathode connected to the second node and its anode grounded. The second capacitor is connected in parallel with the second transient suppression diode; The fifth resistor, one end of which is connected to the second node; An operational amplifier, wherein the positive input terminal of the operational amplifier is connected to the other end of the fifth resistor; A sixth resistor, one end of which is adapted to be connected to a preset power supply; A seventh resistor, one end of which is connected to the other end of the sixth resistor and has a third node, and the other end of which is connected to the negative input terminal of the operational amplifier; The eighth resistor has one end connected to the third node and the other end grounded. The third node is adapted to receive a high-voltage output feedback voltage. The ninth resistor, one end of which is connected to the output terminal of the operational amplifier; The third transient suppression diode, the cathode of which is connected to the other end of the ninth resistor; The third capacitor has one end connected to the anode of the third transient suppression diode and has a fourth node, and the other end of the third capacitor is grounded. The tenth resistor is connected in parallel with the third transient suppression diode; The eleventh resistor has one end connected to the fourth node and the other end connected to the opposite end of the primary oscillation winding.

9. The high-voltage output control circuit of the laser printing equipment according to claim 7, characterized in that, The output rectifier unit includes: A first diode, wherein the anode of the first diode is connected to the opposite terminal of the secondary winding; The second diode, the cathode of which is connected to the opposite terminal of the secondary winding; A fourth capacitor, one end of which is connected to the cathode of the first diode and serves as the output terminal of the output rectifier unit, and the other end of which is connected to the same terminal of the secondary winding. The fifth capacitor has one end connected to the same terminal of the secondary winding, and after being connected to the anode of the second diode, it is connected to the reference ground.

10. A laser printing device, characterized in that, Includes a high-voltage output control circuit for a laser printing device according to any one of claims 1-9.

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