Laser printing apparatus and power control circuit
Patent Information
- Application Number
- CN202522442863.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-18
- Publication Date
- 2026-10-23
- Estimated Expiration
- 2035-11-18
AI Technical Summary
[0003]然而，由于激光打印机器的负载有多种类型，例如马达、传感器、激光光源、系统级芯片（SoC，System on Chip）等，不同类型的负载所需要的供电电压和供电方式均存在差异，因此，在通过机械连锁开关来切断激光光源的供电电源时，为了不影响激光打印机器的正常功能，就需要增加其他部件来控制激光光源的断电与机械连锁开关进行联动，大大增加了机器成本
[0006]根据本申请实施例提供的激光打印设备的电源控制电路，通过第一开关单元与激光打印设备的机器外盖进行联动，以便在机器外盖打开的情况下断开第一直流电对第一负载的供电，并生成断开触发信号，以及通过第二开关单元中的晶体管在断开触发信号的控制下关断，在断开第二直流电对激光光源供电的同时，还能确保第二直流电保持对控制器的供电，确保激光打印设备的正常功能不受影响，因此，本申请通过将激光光源复用控制器的主电源和利用晶体管器件的快速响应性能实现激光光源在机器外盖打开时快速、可靠关断，在保证激光打印设备的安全使用的同时，大大降低了电路成本，提高了激光打印设备的运行安全性和可靠性。
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Figure CN224881577U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of laser printing technology, and in particular to a power control circuit for a laser printing device and a laser printing device having the power control circuit. Background Technology
[0002] In laser printing machines such as printers or copiers, the laser light source (LD, Laser Diode) is the key component for laser printing. However, if the laser light source is exposed during operation, it can cause eye damage. Therefore, to ensure safe use of laser printers, a mechanical interlock switch typically cuts off the power supply to the laser light source when the user opens the machine's outer cover (such as the front or rear door), thus preventing the safety hazards caused by laser light source exposure.
[0003] However, since laser printers have various types of loads, such as motors, sensors, laser light sources, and system-on-chips (SoCs), different types of loads require different power supply voltages and methods. Therefore, when cutting off the power supply to the laser light source through a mechanical interlock switch, in order not to affect the normal function of the laser printer, other components need to be added to control the power outage of the laser light source in conjunction with the mechanical interlock switch, which greatly increases the cost of the machine. Utility Model Content
[0004] The purpose of this application is to provide a power control circuit for a laser printing device and a laser printing device with a power control circuit. By using the main power supply of the laser light source multiplexing controller and utilizing the fast response performance of transistor devices, the laser light source can be quickly and reliably shut off when the machine cover is opened. This greatly reduces the circuit cost while ensuring the safe use of the laser printing device.
[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 power control circuit for a laser printing device, comprising: a first conversion unit configured to convert an input power supply into a first direct current (DC); a first switching unit disposed between the output terminal of the first conversion unit and a first load of the laser printing device, and linked to the machine cover of the laser printing device, so as to disconnect the power supply of the first DC to the first load when the machine cover is opened, and generate a disconnection trigger signal; a second conversion unit connected to the output terminal of the first conversion unit and configured to convert the first DC into a second DC to supply a laser light source of the laser printing device, wherein the voltage of the second DC is less than the voltage of the first DC; and a second switching unit disposed between the output terminal of the second conversion unit and the laser light source, and including at least one transistor, wherein the transistor is turned off under the control of the disconnection trigger signal to disconnect the power supply of the second DC to the laser light source.
[0006] According to the power control circuit of the laser printing equipment provided in the embodiments of this application, the first switching unit is linked with the machine cover of the laser printing equipment so that when the machine cover is opened, the power supply of the first DC power to the first load is disconnected and a disconnection trigger signal is generated. The transistor in the second switching unit is turned off under the control of the disconnection trigger signal. While disconnecting the power supply of the second DC power to the laser source, it can also ensure that the second DC power continues to supply power to the controller, ensuring that the normal function of the laser printing equipment is not affected. Therefore, this application achieves fast and reliable shutdown of the laser source when the machine cover is opened by multiplexing the main power supply of the controller for the laser source and utilizing the fast response performance of transistor devices. While ensuring the safe use of the laser printing equipment, it greatly reduces the circuit cost and improves the operational safety and reliability of the laser printing equipment.
[0007] Optionally, in some embodiments of this application, at least one of the transistors includes a first transistor and a second transistor, the first transistor and the second transistor being connected in series between the output of the second conversion unit and the laser source, so as to be turned off respectively under the control of the disconnect trigger signal.
[0008] Optionally, in some embodiments of this application, the second switching unit further includes: a first resistor, one end of which is adapted to be connected to the power supply terminal of the first load; a second resistor, one end of which is connected to the other end of the first resistor, and the other end of which is grounded; a first transistor, the base of which is connected to one end of the second resistor, the emitter of which is grounded, and the collector of which is connected to the gate of the first transistor; and a third resistor, one end of which is connected to the output terminal of the second conversion unit and the source of the first transistor, and the other end of which is connected to the collector of the first transistor. The system comprises: a fourth resistor, one end of which is adapted to be connected to the power supply terminal of the first load; a fifth resistor, one end of which is connected to the other end of the fourth resistor, and the other end of which is grounded; a second transistor, the base of which is connected to one end of the fifth resistor, the emitter of which is grounded, and the collector of which is connected to the gate of the second transistor; and a sixth resistor, one end of which is connected to the drain of the first transistor and the source of the second transistor, and the other end of which is connected to the collector of the second transistor, the drain of which is adapted to be connected to the power supply terminal of the laser source.
[0009] Optionally, in some embodiments of this application, the power control circuit of the laser printing device further includes: a first trigger unit, which is configured to generate a shutdown signal according to the disconnect trigger signal to control one of the first transistor and the second transistor to be turned off.
[0010] Optionally, in some embodiments of this application, the first triggering unit includes: a seventh resistor, one end of which is connected to the output terminal of the second conversion unit; an eighth resistor, one end of which is connected to the other end of the seventh resistor and has a first node, the other end of which is grounded; a ninth resistor, one end of which is adapted to be connected to the power supply terminal of the first load; a tenth resistor, one end of which is connected to the other end of the ninth resistor and has a second node, the other end of which is grounded; and a first comparator, the positive input terminal of which is connected to the second node, the negative input terminal of which is connected to the first node, and the output terminal of which is used to output the turn-off signal.
[0011] Optionally, in some embodiments of this application, the second switching unit further includes: a fourth resistor, one end of which is connected to the output terminal of the first comparator; a fifth resistor, one end of which is connected to the other end of the fourth resistor, and the other end of which is grounded; a second transistor, the base of which is connected to one end of the fifth resistor, the emitter of which is grounded, and the collector of which is connected to the gate of the second transistor; and a sixth resistor, one end of which is connected to the drain of the first transistor and the source of the second transistor, and the other end of which is connected to the collector of the second transistor, wherein the drain of the second transistor is adapted to be connected to the power supply terminal of the laser source.
[0012] Optionally, in some embodiments of this application, the first trigger unit further includes: an eleventh resistor, one end of which is connected to the output of the first comparator; and a controller, the input pin of which is connected to the other end of the eleventh resistor, and the power supply pin of which is connected to the output of the second conversion unit. The controller is configured to control one of the first transistor and the second transistor to turn off according to the turn-off signal.
[0013] Optionally, in some embodiments of this application, the second switching unit further includes: a twelfth resistor, one end of which is connected to the output pin of the controller, and the other end of which is grounded; a third transistor, the base of which is connected to the output pin of the controller, the emitter of which is grounded, and the collector of which is connected to the gate of the second transistor; and a thirteenth resistor, one end of which is connected to the drain of the first transistor and the source of the second transistor, and the other end of which is connected to the collector of the third transistor, wherein the drain of the second transistor is adapted to be connected to the power supply terminal of the laser source.
[0014] Optionally, in some embodiments of this application, the first conversion unit includes an AC / DC converter, and the second conversion unit includes a DC / DC converter.
[0015] Secondly, embodiments of this application provide a laser printing device, including: a power control circuit for the laser printing device described in the above embodiments.
[0016] According to the embodiments of this application, the laser printing equipment, based on the power control circuit described in the above embodiments, achieves rapid and reliable shutdown of the laser source when the machine cover is opened by using the main power supply of the laser source multiplexing controller and utilizing the fast response performance of transistor devices. This greatly reduces circuit costs and improves the operational safety and reliability of the laser printing equipment while ensuring its safe use. 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 This is a schematic diagram of the power control of a laser printer in the related art; Figure 2 This is a schematic diagram of the power control of another laser printer in the related technology; Figure 3 A circuit diagram of the power control circuit of a laser printing device provided in one embodiment of this application; Figure 4 A circuit diagram of a power control circuit for a laser printing device provided in another embodiment of this application; Figure 5 A circuit diagram of the power control circuit of a laser printing device provided in yet another 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, in order to ensure the safe use of laser printers, a mechanical interlock switch is usually used to cut off the power supply to the laser source when the user opens the machine's outer cover (such as the front or back door), thus avoiding the safety hazards caused by the exposure of the laser source by cutting off the power.
[0021] For example, such as Figure 1 As shown, the input AC220V is converted to DC24V after AC / DC conversion. One path of DC24V is directly supplied to the motor after passing through an interlock switch, and the other path is converted to DC5V after DC / DC conversion, which is supplied to the controller, such as the SoC. The DC24V after interlock switch is further converted to DC5V after another DC / DC conversion, which is supplied to the laser light source LD. In this way, when the machine cover is opened, the interlock switch is opened, disconnecting the power supply to the motor and the laser light source, while ensuring that the controller continues to work.
[0022] Or, such as Figure 2 As shown, the input AC220V is converted to DC24V after AC / DC conversion. One path is directly supplied to the motor after passing through the first interlock switch 1, and the other path is converted to DC5V after DC / DC conversion, which is supplied to the controller, such as the SoC. The DC5V is also supplied to the laser light source LD after passing through the second interlock switch 2. When the machine cover is opened, the first interlock switch 1 and the second interlock switch are disconnected, cutting off the power supply to the motor and the laser light source, while ensuring that the controller continues to work.
[0023] In both of the above methods, when the power supply to the laser source is cut off by a mechanical interlock switch, in order not to affect the normal function of the laser printer, such as keeping the SoC working properly, either a DC / DC converter or a mechanical interlock switch needs to be added. Both of these methods increase circuit costs and are not conducive to machine integration design.
[0024] Therefore, the power control circuit of the laser printing equipment and the laser printing equipment with the power control circuit provided in this application embodiment achieve rapid and reliable shutdown of the laser light source when the machine cover is opened by using the main power supply of the laser light source multiplexing controller and utilizing the fast response performance of transistor devices. This greatly reduces the circuit cost while ensuring the safe use of the laser printing equipment.
[0025] The power control circuit of the laser printing equipment provided in this application and the laser printing equipment having the power control circuit will now be described in detail with reference to the accompanying drawings.
[0026] refer to Figure 3 The diagram shown is a circuit diagram of a power control circuit for a laser printing device according to an embodiment of this application. Figure 3 As shown, the power control circuit of the laser printing equipment includes a first conversion unit 101, a first switching unit 201, a second conversion unit 102, and a second switching unit 202.
[0027] The first conversion unit 101 is configured to convert the input power supply into a first DC power supply. For example, the first conversion unit 101 may include an AC / DC converter capable of converting the input power supply AC220V into DC24V for power supply. The first switching unit 201 is located between the output terminal of the first conversion unit 101 and the first load 301 of the laser printing equipment, and is linked to the machine cover of the laser printing equipment to disconnect the first DC power supply to the first load 301 when the machine cover is opened, and generate a disconnection trigger signal.
[0028] And, as Figure 3 As shown, the input terminal of the second conversion unit 102 is connected to the output terminal of the first conversion unit 101, and is configured to convert the first DC power into a second DC power to supply the laser light source 302 and the controller 303 (e.g., SoC) of the laser printing equipment, respectively. The voltage of the second DC power is lower than the voltage of the first DC power. For example, the second conversion unit 102 may include a DC / DC converter capable of converting the DC 24V first DC power into a DC 5V second DC power for output. One output directly supplies the controller 303 (e.g., SoC), and the other output supplies the laser light source 302 through the second switching unit 202. The second switching unit 202 is disposed between the output terminal of the second conversion unit 102 and the laser light source 302, and includes at least one transistor. The transistor is turned off under the control of a disconnect trigger signal to disconnect the second DC power supply to the laser light source 302.
[0029] Optionally, in a specific example of this application, such as Figure 3 As shown, the first switching unit 201 may include an interlocking switch, which is mechanically linked to the machine cover of the laser printing equipment, such as the front door or the rear door. When the machine cover is opened, the power supply connection between the first DC 24V and the first load 301, such as the machine motor, is disconnected, causing the motor to stop working. At the same time, the power supply to the gate of the transistor in the second switching unit 202 is disconnected, triggering the transistor to turn off, thereby disconnecting the power supply of the second DC 5V to the laser source 302, while maintaining the power supply of the second DC 5V to the controller 303, such as the SoC, to keep the SoC working normally, so as to ensure the normal function of the laser printing equipment.
[0030] Therefore, this application achieves a rapid and reliable shutdown of the laser source 302 when the laser source 302 and the controller 303 (e.g., SoC) share a second DC 5V power supply. Simultaneously, when the interlock switch disconnects the DC 24V power supply to the motor, the power supply to the laser source 302 is disconnected by the rapid shutdown of a semiconductor switching device, such as a transistor, while maintaining the second DC 5V power supply to the SoC. This enables the laser source 302 to be shut off quickly and reliably when the machine cover is opened. While ensuring the safe use of the laser printing equipment, it eliminates the need for an additional mechanical interlock switch or DC / DC converter, significantly reducing circuit costs.
[0031] Optionally, in some embodiments of this application, such as Figure 3 , Figure 4 or Figure 5 As shown, at least one transistor includes a first transistor M1 and a second transistor M2. The first transistor M1 and the second transistor M2 are connected in series between the output terminal of the second conversion unit 102 and the laser source 302 so that they can be turned off respectively under the control of the disconnect trigger signal.
[0032] This embodiment uses two transistors connected in series to control the power-off of the laser source 302, which ensures that the power supply to the laser source 302 is effectively cut off when the machine cover is opened, greatly improving the safety and reliability of the laser printing equipment.
[0033] Optionally, in some embodiments of this application, such as Figure 3 As shown, the second switching unit 202 also includes a first resistor R1, a second resistor R2, a first transistor Q1, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a second transistor Q2, and a sixth resistor R6.
[0034] In this circuit, one end of the first resistor R1 is adapted to be connected to the power supply terminal of the first load 301, i.e., connected between the power supply terminals of the interlock switch and the motor; one end of the second resistor R2 is connected to the other end of the first resistor R1, and the other end of the second resistor R2 is grounded; the base of the first transistor Q1 is connected to one end of the second resistor R2, the emitter of the first transistor Q1 is grounded, and the collector of the first transistor Q1 is connected to the gate of the first transistor M1; one end of the third resistor R3 is connected to the output terminal of the second conversion unit 102 and the source of the first transistor M1, and the other end of the third resistor R3 is connected to the collector of the first transistor Q1; one end of the fourth resistor R4 is adapted to be connected to the power supply terminal of the first load 301, i.e., connected between the power supply terminals of the interlock switch and the motor; one end of the second resistor R2 is connected to the other end of the first resistor R1, and the other end of the second resistor R2 is grounded; one end of the second resistor R3 is connected to the power supply terminal of the first load 301, i.e., connected between the power supply terminals of the interlock switch and the motor; one end of the second resistor R2 is connected to the other end of the first resistor R1, and the other end of the third resistor R3 is connected to the power supply terminal of the first load 301, i.e., connected between the power supply terminals of the interlock switch and the motor; one end of the second resistor R4 is adapted to be connected to the other end of the first resistor R1, i.e., connected between the power supply terminals of the first load 301 and the motor; one end of the second resistor R2 is connected to the other end of the first resistor R1, i.e., connected between the power supply terminals of the first load 301 and the motor; one end of the second resistor R3 is connected to the other end of the first load 301, i.e., connected between the power At the power supply terminal connected to the first load 301, i.e., between the power supply terminal of the interlock switch and the motor, one end of the fifth resistor R5 is connected to the other end of the fourth resistor R4, and the other end of the fifth resistor R5 is grounded. The base of the second transistor Q2 is connected to one end of the fifth resistor R5, the emitter of the second transistor Q2 is grounded, and the collector of the second transistor Q2 is connected to the gate of the second transistor M2. One end of the sixth resistor R6 is connected to the drain of the first transistor M1 and the source of the second transistor M2, and the other end of the sixth resistor R6 is connected to the collector of the second transistor Q2. The drain of the second transistor M2 is adapted to be connected to the power supply terminal of the laser source 302.
[0035] In this embodiment, when the laser printing equipment is working normally, the machine cover is closed and the interlock switch is closed. At this time, the first DC 24V power supply powers the first load 301, such as the motor, and the motor works normally. The first DC 24V power supply is divided by the first resistor R1 and the second resistor R2, making the base of the first transistor Q1 high level, and the first transistor Q1 conducts. This pulls the gate of the first transistor M1 to ground, and the first transistor M1 conducts. Similarly, the first DC 24V power supply is divided by the fourth resistor R4 and the fifth resistor R5, making the base of the second transistor Q2 high level, and the second transistor Q2 conducts. This pulls the gate of the second transistor M2 to ground, and the second transistor M2 conducts. Thus, the second DC 5V power supply powers the laser source 302, and the laser of the laser printing equipment works normally. When the machine cover is opened, the interlock switch is disconnected. At this time, the first DC 24V power supply is disconnected from the first load 301, such as the motor, so the motor cannot work. The first DC 24V power supply is also disconnected from the second switching unit 202. The base of the first transistor Q1 is at a low level, so the first transistor Q1 is turned off. The gate of the first transistor M1 is pulled up to the second DC 5V power supply through the third resistor R3, so the first transistor M1 is turned off. Similarly, the base of the second transistor Q2 is at a low level, so the second transistor Q2 is turned off. The gate of the second transistor M2 is pulled up to the second DC 5V power supply through the sixth resistor R6, so the second transistor M2 is turned off. Thus, the second DC 5V power supply to the laser source 302 is disconnected. The second DC 5V power supply continues to supply power to the controller 303, such as the SoC.
[0036] Therefore, the second switching unit 202 in this embodiment is composed of components such as resistors, transistors, and MOSFETs, which facilitates integrated design. Furthermore, the electronic switch designed with simple components can greatly reduce circuit costs, while also ensuring high reliability and easy implementation of fast turn-off function.
[0037] Optionally, in some embodiments of this application, such as Figure 4 or Figure 5 As shown, the power control circuit of the laser printing device also includes a first trigger unit 401, which is configured to generate a shutdown signal based on a disconnect trigger signal to control the shutdown of one of the first transistor M1 and the second transistor M2.
[0038] The first trigger unit 401 can directly detect the disconnection trigger signal when the machine cover is open and control one of the first transistor M1 and the second transistor M2 to turn off. The other of the first transistor M1 and the second transistor M2 is directly triggered to turn off by the disconnection trigger signal. Thus, by using two shutdown mechanisms to control the first transistor M1 and the second transistor M2 to turn off respectively, the power supply of the laser light source 302 is effectively shut off when the machine cover is open, which greatly improves the safety and reliability of the laser printing equipment.
[0039] Optionally, in one embodiment of this application, such as Figure 4 or Figure 5 As shown, the first trigger unit 401 includes a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, and a first comparator 4011.
[0040] Among them, one end of the seventh resistor R7 is connected to the output terminal of the second conversion unit 102, one end of the eighth resistor R8 is connected to the other end of the seventh resistor R7 and has a first node, the other end of the eighth resistor R8 is grounded, one end of the ninth resistor R9 is adapted to be connected to the power supply terminal of the first load 301, one end of the tenth resistor R10 is connected to the other end of the ninth resistor R9 and has a second node, the other end of the tenth resistor R10 is grounded, the positive input terminal of the first comparator 4011 is connected to the second node, the negative input terminal of the first comparator 4011 is connected to the first node, and the output terminal of the first comparator 4011 is used to output a turn-off signal.
[0041] And, as Figure 4 As shown, the second switching unit 202 also includes a fourth resistor R4, a fifth resistor R5, a second transistor Q2, and a sixth resistor R6. One end of the fourth resistor R4 is connected to the output terminal of the first comparator 4011. One end of the fifth resistor R5 is connected to the other end of the fourth resistor R4, and the other end of the fifth resistor R5 is grounded. The base of the second transistor Q2 is connected to one end of the fifth resistor R5, the emitter of the second transistor Q2 is grounded, and the collector of the second transistor Q2 is connected to the gate of the second transistor M2. One end of the sixth resistor R6 is connected to the drain of the first transistor M1 and the source of the second transistor M2, and the other end of the sixth resistor R6 is connected to the collector of the second transistor Q2. The drain of the second transistor M2 is adapted to be connected to the power supply terminal of the laser source 302.
[0042] In this embodiment, when the laser printing equipment is working normally, the machine cover is closed and the interlock switch is closed. At this time, the first DC 24V power supply powers the first load 301, such as the motor, and the motor works normally. The first DC 24V power supply is divided by the first resistor R1 and the second resistor R2, making the base of the first transistor Q1 high and turning on the first transistor Q1. This pulls the gate of the first transistor M1 to ground, and the first transistor M1 turns on. The first DC 24V power supply is divided by the ninth resistor R9 and the tenth resistor R10 and then supplied to the positive input terminal of the first comparator 4011. The second DC 5V power supply is divided by the seventh resistor R7 and the eighth resistor R8 and then supplied to the negative input terminal of the first comparator 4011. The first comparator 4011 outputs a high level, making the base of the second transistor Q2 high and turning on the second transistor Q2. This pulls the gate of the second transistor M2 to ground, and the second transistor M2 turns on. Thus, the second DC 5V power supply powers the laser source 302, and the laser of the laser printing equipment works normally. When the machine cover is opened, the interlock switch is disconnected. At this time, the first DC 24V power supply is disconnected from the first load 301, such as the motor, so the motor cannot work. The first DC 24V power supply is also disconnected from the second switch unit 202 and the first trigger unit 401. The base of the first transistor Q1 is at a low level, so the first transistor Q1 is turned off. The gate of the first transistor M1 is pulled up to the second DC 5V power supply through the third resistor R3, so the first transistor M1 is turned off. The voltage at the positive input terminal of the first comparator 4011 is less than the voltage at the negative input terminal, so the output of the first comparator 4011 flips and outputs a low level. The base of the second transistor Q2 is at a low level, so the second transistor Q2 is turned off, so the second transistor M2 is turned off. The first transistor M1 and the second transistor M2 together disconnect the second DC 5V power supply from the laser source 302. The second DC 5V power supply continues to supply power to the controller 303, such as the SoC.
[0043] Therefore, this embodiment controls the second transistor M2 to turn off by setting a first trigger unit 401. In this way, even if the first transistor M1 cannot be turned off due to an abnormality, the second transistor M2 can be reliably turned off under the control of the first trigger unit 401. Thus, the electronic switch designed based on simple components can realize the dual shutdown function of the power supply of the laser source 302, which not only greatly reduces the circuit cost, but also has high reliability and is easy to realize the fast shutdown function.
[0044] Alternatively, in another embodiment of this application, such as Figure 5As shown, the first trigger unit 401 also includes an eleventh resistor R11 and a controller 303, such as a SoC. One end of the eleventh resistor R11 is connected to the output of the first comparator 4011, the input pin of the controller 303 is connected to the other end of the eleventh resistor R11, and the power supply pin of the controller 303 is connected to the output of the second conversion unit 102. The controller 303 is configured to control the shutdown of one of the first transistor M1 and the second transistor M2 according to the shutdown signal.
[0045] The first trigger unit 401 can detect the switching state of the interlock switch when the machine cover is opened through the first comparator 4011 and the controller 303. Based on the switching state of the interlock switch, it determines that when the interlock switch is disconnected, it directly controls one of the first transistor M1 and the second transistor M2 to turn off. The other of the first transistor M1 and the second transistor M2 is directly triggered to turn off by the disconnection trigger signal. In this way, by controlling the first transistor M1 and the second transistor M2 to turn off respectively through two shutdown mechanisms, it ensures that the power supply of the laser light source 302 is effectively shut off when the machine cover is opened, which greatly improves the safety and reliability of the laser printing equipment.
[0046] Furthermore, such as Figure 5 As shown, the second switching unit 202 also includes a twelfth resistor R12, a third transistor Q3, and a thirteenth resistor R13. One end of the twelfth resistor R12 is connected to the output pin of the controller 303, and the other end of the twelfth resistor R12 is grounded. The base of the third transistor Q3 is connected to the output pin of the controller 303, the emitter of the third transistor Q3 is grounded, and the collector of the third transistor Q3 is connected to the gate of the second transistor M2. One end of the thirteenth resistor R13 is connected to the drain of the first transistor M1 and the source of the second transistor M2, and the other end of the thirteenth resistor R13 is connected to the collector of the third transistor Q3. The drain of the second transistor M2 is adapted to be connected to the power supply terminal of the laser source 302.
[0047] In this embodiment, when the laser printing equipment is working normally, the machine cover is closed and the interlock switch is closed. At this time, the first DC 24V power supply powers the first load 301, such as the motor, and the motor works normally. The first DC 24V power supply is divided by the first resistor R1 and the second resistor R2, making the base of the first transistor Q1 high level, and the first transistor Q1 conducts, pulling the gate of the first transistor M1 down to ground, and the first transistor M1 conducts. The first DC 24V power supply is then divided by the ninth resistor R9 and the tenth resistor R10 and supplied to the first load 301. The positive input terminal of the first comparator 4011 receives the second DC power of 5V, which is then divided by the seventh resistor R7 and the eighth resistor R8 and supplied to the negative input terminal of the first comparator 4011. The first comparator 4011 outputs a high level to the controller 303. When the controller 303 detects the high level signal, it pulls the base of the third transistor Q3 high, turning on the third transistor Q3 and pulling the gate of the second transistor M2 down to ground, turning on the second transistor M2. Thus, the second DC power of 5V supplies power to the laser source 302, and the laser of the laser printing equipment works normally. When the machine cover is opened, the interlock switch is disconnected. At this time, the first DC 24V power supply is disconnected from the first load 301, such as the motor, so the motor cannot work. The first DC 24V power supply is also disconnected from the connection between the second switch unit 202 and the first trigger unit 401. The base of the first transistor Q1 is at a low level, so the first transistor Q1 is turned off. The gate of the first transistor M1 is pulled up to the second DC 5V power supply through the third resistor R3, so the first transistor M1 is turned off. The voltage at the positive input terminal of the first comparator 4011 is less than the voltage at the negative input terminal, so the output of the first comparator 4011 flips and outputs a low level. The controller 303 detects that the interlock switch is open and pulls the base of the third transistor Q3 low, so the third transistor Q3 is turned off. Thus, the second transistor M2 is turned off. The first transistor M1 and the second transistor M2 together disconnect the second DC 5V power supply from the laser source 302. The second DC 5V power supply continues to supply power to the controller 303, such as the SoC.
[0048] Therefore, this embodiment uses a first comparator 4011 and a controller 303 to detect the state of the interlock switch. When the interlock switch is detected to be open, the second transistor M2 is controlled to turn off. In this way, even if the first transistor M1 cannot be turned off due to an abnormality, the second transistor M2 can be reliably turned off under the control of the controller 303. Thus, the dual shutdown of the power supply of the laser source 302 can be achieved by using the fast response function of the controller 303 and the electronic switch designed based on simple components. This not only greatly reduces the circuit cost, but also has high reliability and is easy to implement fast shutdown function.
[0049] In summary, the power control circuit of the laser printing equipment provided in this application embodiment is linked with the machine cover of the laser printing equipment through the first switching unit. This allows the first DC power supply to the first load to be disconnected when the machine cover is opened, generating a disconnection trigger signal. The transistor in the second switching unit is turned off under the control of the disconnection trigger signal. While disconnecting the second DC power supply to the laser source, the second DC power supply to the controller is also ensured, ensuring that the normal function of the laser printing equipment is not affected. Therefore, this application achieves rapid and reliable shutdown of the laser source when the machine cover is opened by multiplexing the main power supply of the controller and utilizing the fast response performance of transistor devices. This greatly reduces circuit costs and improves the operational safety and reliability of the laser printing equipment while ensuring its safe use.
[0050] In addition, such as Figure 6 As shown, this application embodiment also provides a laser printing device 200, which includes the power control circuit 100 of the laser printing device described in the above embodiment.
[0051] According to the laser printing equipment 200 provided in the embodiments of this application, based on the power control circuit 100 described in the above embodiments, the laser light source is quickly and reliably shut off when the machine cover is opened by using the main power supply of the laser light source multiplexing controller and utilizing the fast response performance of transistor devices. While ensuring the safe use of the laser printing equipment, the circuit cost is greatly reduced and the operational safety and reliability of the laser printing equipment are improved.
[0052] 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.
[0053] 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 power control circuit for a laser printing device, characterized in that, include: A first conversion unit, configured to convert the input power supply into a first direct current; The first switching unit is disposed between the output terminal of the first conversion unit and the first load of the laser printing equipment, and is linked with the machine cover of the laser printing equipment so as to disconnect the power supply of the first DC power to the first load when the machine cover is opened, and generate a disconnection trigger signal. The second conversion unit has its input terminal connected to the output terminal of the first conversion unit and is configured to convert the first DC power into a second DC power to supply the laser light source of the laser printing device, wherein the voltage of the second DC power is less than the voltage of the first DC power. The second switching unit is disposed between the output terminal of the second conversion unit and the laser source, and includes at least one transistor. The transistor is turned off under the control of the disconnect trigger signal to disconnect the power supply of the second DC power to the laser source.
2. The power control circuit of the laser printing equipment according to claim 1, characterized in that, At least one of the transistors includes a first transistor and a second transistor, which are connected in series between the output of the second conversion unit and the laser source, so as to be turned off respectively under the control of the disconnect trigger signal.
3. The power control circuit of the laser printing equipment according to claim 2, characterized in that, The second switching unit further includes: A first resistor, one end of which is adapted to be connected to the power supply terminal of the first load; A second resistor, one end of which is connected to the other end of the first resistor, and the other end of the second resistor is grounded; The first transistor has its base connected to one end of the second resistor, its emitter grounded, and its collector connected to the gate of the first transistor. The third resistor has one end connected to the output terminal of the second conversion unit and the source of the first transistor, and the other end connected to the collector of the first transistor. A fourth resistor, one end of which is adapted to be connected to the power supply terminal of the first load; The fifth resistor has one end connected to the other end of the fourth resistor, and the other end of the fifth resistor is grounded. The second transistor has its base connected to one end of the fifth resistor, its emitter grounded, and its collector connected to the gate of the second transistor. A sixth resistor, one end of which is connected to the drain of the first transistor and the source of the second transistor, and the other end of which is connected to the collector of the second transistor. The drain of the second transistor is adapted to be connected to the power supply terminal of the laser source.
4. The power control circuit of the laser printing equipment according to claim 2, characterized in that, Also includes: A first triggering unit is configured to generate a shutdown signal based on the disconnect trigger signal to control the shutdown of one of the first transistor and the second transistor.
5. The power control circuit of the laser printing equipment according to claim 4, characterized in that, The first triggering unit includes: The seventh resistor, one end of which is connected to the output terminal of the second conversion unit; An eighth resistor, one end of which is connected to the other end of the seventh resistor and has a first node, and the other end of the eighth resistor is grounded; A ninth resistor, one end of which is adapted to be connected to the power supply terminal of the first load; The tenth resistor has one end connected to the other end of the ninth resistor and has a second node, and the other end of the tenth resistor is grounded. A first comparator, the positive input of which is connected to the second node, the negative input of which is connected to the first node, and the output of which is used to output the turn-off signal.
6. The power control circuit of the laser printing equipment according to claim 5, characterized in that, The second switching unit further includes: A fourth resistor, one end of which is connected to the output of the first comparator; The fifth resistor has one end connected to the other end of the fourth resistor, and the other end of the fifth resistor is grounded. The second transistor has its base connected to one end of the fifth resistor, its emitter grounded, and its collector connected to the gate of the second transistor. A sixth resistor, one end of which is connected to the drain of the first transistor and the source of the second transistor, and the other end of which is connected to the collector of the second transistor. The drain of the second transistor is adapted to be connected to the power supply terminal of the laser source.
7. The power control circuit of the laser printing equipment according to claim 5, characterized in that, The first triggering unit further includes: The eleventh resistor, one end of which is connected to the output of the first comparator; The controller has an input pin connected to the other end of the eleventh resistor and a power supply pin connected to the output of the second conversion unit. The controller is configured to control the shutdown of one of the first transistor and the second transistor according to the shutdown signal.
8. The power control circuit of the laser printing equipment according to claim 7, characterized in that, The second switching unit further includes: The twelfth resistor has one end connected to the output pin of the controller and the other end grounded. The third transistor has its base connected to the output pin of the controller, its emitter grounded, and its collector connected to the gate of the second transistor. The thirteenth resistor has one end connected to the drain of the first transistor and the source of the second transistor, and the other end connected to the collector of the third transistor. The drain of the second transistor is adapted to be connected to the power supply terminal of the laser source.
9. The power control circuit of the laser printing equipment according to any one of claims 1-8, characterized in that, The first conversion unit includes an AC / DC converter, and the second conversion unit includes a DC / DC converter.
10. A laser printing device, characterized in that, Includes a power control circuit for a laser printing device according to any one of claims 1-9.