CN117712988A

CN117712988A - High-voltage protection device and image forming apparatus

Info

Publication number: CN117712988A
Application number: CN202311711606.1A
Authority: CN
Inventors: 彭继兵; 陈泽福; 刘智豪; 张中毅; 黄香川
Original assignee: Zhuhai Pantum Electronics Co Ltd
Current assignee: Zhuhai Pantum Electronics Co Ltd
Priority date: 2023-12-12
Filing date: 2023-12-12
Publication date: 2024-03-15

Abstract

The embodiment of the application provides a high-voltage protection device and image forming device, and the high-voltage protection device includes: the device comprises a detection module and a voltage turn-off module; the detection module is used for acquiring an output value of the high-voltage generation module and transmitting a first signal and/or a high-voltage feedback value to the control module, wherein the first signal is a first signal used for representing whether the high voltage is abnormal or not; the voltage turn-off module is used for receiving the first power and outputting the second power; controlling output of second power based on a second signal output by the control module, wherein the second signal is a second signal used for representing whether the high voltage is abnormal or not, and the high voltage generation module generates the high voltage based on the second power; the control module outputs a second signal based on the first signal and/or the input of the high-voltage feedback value, and controls the on and off of the voltage turn-off module to control the output of the second power based on the output of the second signal.

Description

High-voltage protection device and image forming apparatus

Technical Field

The present disclosure relates to the field of image forming technologies, and in particular, to a high voltage protection device and an image forming apparatus.

Background

In operation of a high-voltage board in an image forming apparatus, there is a possibility that load abnormality or damage to components inside the high-voltage board may occur to cause an excessive output current of the high-voltage board, and quality of a printed image of the image forming apparatus and a hardware circuit of a high-voltage portion may be affected. The power supply of the high-voltage board is generally performed by converting a low-voltage power (for example, 24V for an engine, hereinafter 24VS, that is, a power supply for driving the engine of the image forming apparatus, and a first power) provided by a power board through a main control board.

Currently, during operation of an image forming apparatus, whether or not there is an abnormality in the output of a high-voltage board is detected by an abnormality detection circuit in the image forming apparatus. When the abnormality detection circuit detects that the output of the high-voltage board is abnormal, the high-voltage power supply can be powered off, so that the high-voltage power supply does not supply power to the high-voltage board.

However, the low-voltage power supply may supply power to components such as a motor component, a fan, and a laser scanning unit (Laser Scanning Unit, LSU, laser scanning unit) in the image forming apparatus, in addition to the high-voltage board of the image forming apparatus. When the high-voltage board is abnormal, the power-off treatment of the motor, the fan, the laser scanning unit and other components can be stopped directly, so that the image forming device cannot radiate heat by using the fan in an abnormal state, and the heat in the image forming device in the abnormal state is not easy to be removed from the machine body.

Disclosure of Invention

The embodiment of the application provides a high-voltage protection device and an image forming device, which can control a high-voltage circuit not to be in a working state any more when the high-voltage circuit is abnormal, and the main control board is not influenced to supply power for other hardware modules.

In a first aspect, an embodiment of the present application provides a high voltage protection device, including a control module and a high voltage generation module; the high-voltage generation module is used for generating high voltage; the control module is used for controlling the output of the first power; the high voltage protection device further includes: the device comprises a detection module and a voltage turn-off module;

the detection module is used for acquiring the output value of the high-voltage generation module and transmitting a first signal and/or a high-voltage feedback value to the control module, wherein the first signal is a first signal used for representing whether the high voltage is abnormal or not;

the voltage turn-off module is used for receiving the first power and outputting second power; controlling output of the second electric power based on a second signal output by the control module, wherein the second signal is a second signal for representing whether high voltage is abnormal or not, and the high voltage generation module generates high voltage based on the second electric power;

the control module outputs the second signal based on the input of the first signal and/or the high-voltage feedback value, and controls the on and off of the voltage turn-off module to control the output of the second power based on the output of the second signal.

Optionally, the control module is further configured to start detecting the first signal when the imaging medium detection sensor detects that the leading end of the imaging medium passes, and stop detecting the first signal when the trailing end of the imaging medium is detected to leave.

Optionally, the control module is further configured to start detecting the first signal after a predetermined time when the imaging medium detection sensor detects a front end delay of the imaging medium.

Optionally, the second signal is at a high level when the high voltage output is normal and outputs a low level when the high voltage output is abnormal; or alternatively

The second signal is low level when the high voltage output is normal and outputs high level when the high voltage output is abnormal.

Optionally, the control module is further configured to cut off the second power by the first control mode when a high voltage abnormality is detected during image formation.

Optionally, the first control mode specifically includes that printing of the current image forming job is executed first, and after execution is finished, the second signal is switched to a corresponding level state when the high-voltage output is abnormal, and output of the second power is turned off.

Optionally, the control module is further configured to cut off the second power by a second control mode when a high voltage abnormality is detected during non-image formation.

Optionally, the second control mode is specifically to directly turn off the output of the second power.

Optionally, the high voltage protection device further includes a conversion module, where the conversion module is configured to receive the output value of the detection module, convert the output value, and feed back the converted output value to the control module.

Optionally, the conversion module is configured to receive an output value of the detection module and level-convert the output value during image formation, and output the first signal to a first input interface of the control module through a first output end of the conversion module; or alternatively

The conversion module is used for receiving the output value of the detection module and converting the output value during non-image formation, outputting the high-voltage feedback value through a second output end of the conversion module, outputting the high-voltage feedback value to the analog-to-digital converter, converting an analog signal of the high-voltage feedback value into a digital signal through the analog-to-digital converter, and outputting the digital signal to a second input interface of the control module.

Optionally, the control module is configured to determine that the high voltage is abnormal and output a first fault code when the first signal output by the first output end of the conversion module is received and the first signal meets a first preset condition, where the first fault code is used for the image forming apparatus to output an alarm signal; or alternatively

The control module is used for judging that the high voltage is abnormal and outputting a second fault code when the high voltage feedback value output by the second output end of the conversion module is received and the high voltage feedback value meets a second preset condition, and the second fault code is used for outputting an alarm signal by the image forming device.

Optionally, the first preset condition is that the first signal is continuously detected to be a level signal indicating that the high voltage generation module is abnormal, and an abnormal count value of the first signal is detected to be greater than a first preset value every first preset time in an image forming period; or alternatively

And when the number of the high-voltage feedback values detected every second preset time in the non-image forming period is the second preset value, calculating the average value of the high-voltage feedback values for a plurality of times, wherein the calculated average value is larger than or equal to a third preset value.

In a second aspect, embodiments of the present application provide an image forming apparatus including the high voltage protection apparatus according to any one of the first aspects.

Therefore, the embodiment of the application provides a high-voltage protection device and an image forming device, which solve the problem that when the high-voltage board is abnormal, the components such as a motor, a fan, a laser scanning unit and the like can be possibly caused to stop working by directly carrying out power-off treatment on the high-voltage board, so that the image forming device cannot use the fan to carry out heat dissipation on a machine body in an abnormal state, and the heat in the image forming device in the abnormal state is not beneficial to being removed outside the machine body.

Because the power supplied by the main control board used by the module for generating high voltage on the high voltage board is the same low voltage power supply as the power supply used by the direct current motor, the laser scanning unit component, the fan and other components in the image forming device. The following technical effects can be achieved by the hardware scheme of the embodiment: through setting up the voltage and turn-off the module between control module and high voltage generation module for when detection module detects that high voltage generation module appears unusual, can be in the off state through control module control voltage and turn-off the module, make the master control board no longer can be through the high voltage generation module power supply on the high voltage board of voltage turn-off the module, and the master control board can also supply power for other hardware this moment. When the high-voltage generating module is abnormal, the power supply of the high-voltage generating module is cut off, and the power supply of other hardware power utilization components controlled by the same low voltage in the image forming device is not cut off, so that the normal use of other power utilization components is ensured.

Drawings

Fig. 1 is a schematic diagram of a high-voltage protection device according to an embodiment of the present application;

fig. 2 is a schematic circuit diagram of a voltage shutdown module according to an embodiment of the present disclosure;

FIG. 3 is a schematic diagram of detecting a position of a sheet by a sheet relay sensor according to an embodiment of the present application;

FIG. 4 is a schematic diagram showing a voltage change with time of an image forming apparatus according to an embodiment of the present application during an image forming process;

fig. 5 is a schematic structural diagram of another high-voltage protection device according to an embodiment of the present application;

fig. 6 is a schematic flow chart of a control method according to an embodiment of the present application;

FIG. 7 is a flow chart of another control method according to an embodiment of the present disclosure;

fig. 8 is a schematic structural diagram of still another high-voltage protection device according to an embodiment of the present application;

FIG. 9 is a schematic diagram of a result including a power detection circuit according to an embodiment of the present application;

fig. 10 is a schematic circuit diagram of a circuit structure including an output current detection circuit according to an embodiment of the present application;

FIG. 11 is a schematic diagram of another circuit structure including an output current detection circuit according to an embodiment of the present disclosure;

fig. 12 is a schematic diagram of a circuit structure including a current feedback circuit according to an embodiment of the present application;

fig. 13 is a schematic circuit diagram of a circuit structure including an abnormality detection circuit according to an embodiment of the present application;

fig. 14 is a schematic circuit diagram of a circuit structure including a fault feedback circuit according to an embodiment of the present application;

Fig. 15 is a schematic circuit diagram of a circuit structure including a hardware protection circuit according to an embodiment of the present application;

fig. 16 is a schematic diagram of a circuit structure including an operational amplifier protection circuit according to an embodiment of the present application;

fig. 17 is a schematic view of a part of the internal structure of an image forming apparatus according to an embodiment of the present application.

Specific embodiments of the present disclosure have been shown by way of the above drawings and will be described in more detail below. These drawings and the written description are not intended to limit the scope of the disclosed concepts in any way, but rather to illustrate the disclosed concepts to those skilled in the art by reference to specific embodiments.

Detailed Description

Reference will now be made in detail to exemplary embodiments, examples of which are illustrated in the accompanying drawings. When the following description refers to the accompanying drawings, the same numbers in different drawings refer to the same or similar elements, unless otherwise indicated. The implementations described in the following exemplary examples are not representative of all implementations consistent with the present disclosure. Rather, they are merely examples of apparatus and methods consistent with some aspects of the present disclosure as detailed in the accompanying claims.

In embodiments of the present application, "at least one" means one or more, and "a plurality" means two or more. "and/or", describes an association relationship of an association object, and indicates that there may be three relationships, for example, a and/or B, and may indicate: there are three cases, a alone, a and B together, and B alone, wherein a, B may be singular or plural. In the text description of the present application, the character "/" generally indicates that the front-rear association object is an or relationship.

In order to facilitate the clear description of the technical solutions of the embodiments of the present application, the following simply describes some terms and techniques related to the embodiments of the present application:

in operation, the high-voltage board in the image forming apparatus supplies power to the high-voltage board through the high-voltage power supply, and the situation that the output current of the high-voltage board is overlarge due to abnormal load or damage of components in the high-voltage board may occur, which may affect the quality of a printed image of the image forming apparatus and a hardware circuit of the high-voltage part. Therefore, it is necessary to detect an abnormal condition of high voltage during the operation of the image forming apparatus.

In the prior art, an abnormality detection circuit may be provided in an image forming apparatus, and in the operation of the image forming apparatus, the current output from a high-voltage board is detected, and when the current is detected to be too large, a high-voltage abnormality alarm is triggered. The image forming apparatus triggers an error mechanism to instantly turn off a high voltage power supply that supplies voltage to a high voltage board.

However, the high-voltage power supply (i.e., the engine driving power supply of the image forming apparatus, the first power, the engine 24V) may supply power to components such as a motor component and a fan in the image forming apparatus, in addition to the high-voltage board of the image forming apparatus. The power-off processing mode of the high-voltage power supply can possibly lead to the stop of the operation of the motor, the fan and other components, so that the heat of the body of the image forming device in an abnormal state can not be discharged in time, and the heat of the body in the abnormal state can be aggravated to influence the service life of hardware elements.

The embodiment of the application provides a high-voltage protection device, which comprises a voltage shut-off module, wherein the voltage shut-off module is arranged between a control module and a high-voltage generation module of an image forming device, and can realize two states of opening and closing under the control of the control module. When the voltage turn-off module is in a state of normally supplying power to the high-voltage board, the main control board in the image forming device can supply power to the high-voltage generation module through the voltage turn-off module. When the voltage turn-off module is in a voltage turn-off state which can not normally supply power to the high-voltage board, the main control board can not supply power to the high-voltage generation module through the voltage turn-off module. Therefore, when the detection module detects that the high-voltage generation module is abnormal, the control module can control the voltage shut-off module to be in a shut-off state, so that the main control board can not supply power to the high-voltage generation module any more, and when the voltage shut-off module is in the shut-off state, the main control board can still supply power to components such as a fan.

In the embodiments of the present application, the image forming apparatus includes, but is not limited to, a printer, a copier, a facsimile machine, a scanner, a multifunctional all-in-one machine that integrates functions of printing, copying, faxing, scanning, and the like, and functions to print images or characters on an image forming medium.

Hereinafter, the high voltage protection device and the image forming apparatus provided in the present application will be described in detail by specific examples. It is to be understood that the following embodiments may be combined with each other and that some embodiments may not be repeated for the same or similar concepts or processes.

Fig. 1 is a schematic diagram of a high voltage protection device according to an embodiment of the present application.

As shown in fig. 1, a high-voltage protection device provided in an embodiment of the present application includes a control module and a high-voltage generation module; the high-voltage generation module is used for generating high voltage; the control module is used for controlling the output of the first power; the high voltage protection device further includes: the device comprises a detection module and a voltage turn-off module;

the detection module is used for acquiring an output value of the high-voltage generation module and transmitting a first signal and/or a high-voltage feedback value to the control module, wherein the first signal is a first signal used for representing whether the high voltage is abnormal or not;

the voltage turn-off module is used for receiving the first power and outputting the second power; controlling output of second power based on a second signal output by the control module, wherein the second signal is a second signal used for representing whether the high voltage is abnormal or not, and the high voltage generation module generates the high voltage based on the second power;

The control module outputs a second signal based on the first signal and/or the input of the high-voltage feedback value, and controls the on and off of the voltage turn-off module to control the output of the second power based on the output of the second signal.

When the control module can control the voltage turn-off module to be in a state of normally supplying power to the high-voltage board, the main control board can supply power to the high-voltage generation circuit through the control module and the voltage turn-off module, so that the high-voltage generation module can generate high voltage and output the high voltage. The detection module may obtain an output value of the high voltage generation module and transmit a first signal to the control module, where the first signal is a first signal used to characterize whether the high voltage is abnormal, for example, the first signal may be an hv_err signal.

When the control module receives the first signal and/or the high-voltage feedback value, the control module can output a second signal based on the input of the first signal and/or the high-voltage feedback value and control the on and off of the voltage turn-off module based on the output of the second signal to control the output voltage turn-off module of the second power, so that the voltage turn-off module and the high-voltage generation module are in a disconnected state, and the main control board cannot supply power to the high-voltage generation module through the control module and the voltage turn-off module, wherein the second signal can be an HV_SW signal, and the second power can be 24VS_A, namely, the power supply power for controlling the high-voltage generation module.

It should be noted that, the image forming apparatus may further include a hardware module (not shown in fig. 1) such as a fan, an LSU, and a BLDC (brushless direct current motor), and the main control board may supply power to the hardware module through the control module.

Therefore, when the high-voltage generation module is abnormal, the control module controls the voltage turn-off module to be in a turned-off state, so that the voltage generation module can be only controlled to be powered off, and the main control board is not influenced to supply power to other hardware modules in the image forming device.

In the embodiment of the application, the control module may control the state of the voltage shutdown module by sending the second signal to the voltage shutdown module.

For example, when the first signal is a signal indicating that the high voltage generating module is abnormal, it may be determined that the high voltage generating module is abnormal, and the control module may send a second signal of the first level state to the voltage shutdown module to control the voltage shutdown module to be in a high voltage shutdown state in which the high voltage cannot be output, where the second signal includes a high-low level signal.

In addition, if the high voltage feedback value is compared with the reference value to determine that the high voltage is abnormal, it may be determined that the high voltage generating module is abnormal, and the control module may also send a second signal in the first level state to the voltage shutdown module to control the voltage shutdown module to be in a high voltage shutdown state in which the high voltage cannot be output, where the second signal includes a high-low level signal.

When the image forming apparatus is operating normally, that is, the first signal is not a signal indicating that the high voltage generating module is abnormal, it may be determined that the high voltage generating module is not abnormal, and the control module may send a second signal in a second level state to the voltage shutdown module to control the voltage shutdown module to be in a state of normally supplying power to the high voltage board.

The first level state may be a low level signal and the second level state may be a high level signal. For example, when the high voltage output is normal, the second signal is at a high level, corresponding to the second level state, and when the high voltage output is abnormal, the second signal is at a low level, corresponding to the first level state; in addition, the second signal may be low level when the high voltage output is normal, and corresponds to the second level state, and the second signal may be high level when the high voltage output is abnormal, and corresponds to the first level state, which is not limited in this application.

Taking the state of controlling the voltage shutdown module based on the level signal of the control module as an example, the circuit composition of the voltage shutdown module can be shown in fig. 2, and fig. 2 is a schematic diagram of the circuit structure of the voltage shutdown module according to the embodiment of the present application.

As shown in fig. 2, the voltage turn-off module may include a control circuit, a capacitor C1, a capacitor C2, a capacitor C3, a capacitor C4, a switch Q101, and a control circuit, where RL is a load. In the circuit shown in fig. 2, +24v is one end of the input voltage of the main control board.

One end of the capacitor C1 and one end of the capacitor C2 are connected with the main control board and the first end of the switch Q101, the other ends of the capacitor C1 and the capacitor C2 are grounded, the second end of the switch Q101 is connected with the capacitor C3, the capacitor C4 and the load RL, and the third end of the switch Q101 is connected with the output end of the control circuit.

As shown in fig. 2, the control circuit includes a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R5, a switch Q102, and a switch Q103.

One end of the resistor R1 is an input end of a control signal, and can receive the control signal sent by the control module, the other end of the resistor R1 is connected with one end of the resistor R2 and a first end of the switch Q102, the other end of the resistor R2 and a second end of the switch Q102 are both grounded, a third end of the switch Q102 is connected with one end of the resistor R3 and one end of the resistor R5, a voltage of 5V is input to the other end of the resistor R3, the other end of the resistor R5 is connected with a first end of the switch Q103, a second end of the switch Q103 is grounded, a third end of the switch Q103 is connected with a third end of the resistor R4 and a third end of the switch Q101, and a voltage of 24V is input to the other end of the resistor R4, which can be input through a main control board.

As shown in fig. 2, when the switch Q101 is in an on state, the voltage input by the main control board may be supplied to the load RL through the switch Q101, and when the switch Q101 is in an off state, the voltage input by the main control board may not be supplied to the load RL through the switch Q101. Therefore, the control module controls the state of the voltage turn-off module as shown in fig. 2, and can control the switching state of the switch Q101 by inputting different control signals to control whether the voltage input by the main control board can be supplied to the load RL through the switch Q101. As can be appreciated, when the second signal is at a high level, the switch Q101 and the switch Q102 are turned on, the voltage turn-off module is in a state of normally supplying power to the high voltage board, the second power 24vs_a for controlling the high voltage generation module can be normally output, when the second signal is at a low level, the switch Q101 and the switch Q102 are turned off, the switch Q103 is turned on, the gate voltage of the switch Q101 is pulled down, the second power 24vs_a for controlling the high voltage generation module can not be normally output, in addition, the voltage turn-off module can be set to be in an off state according to different situations, the second power 24vs_a for controlling the high voltage generation module can not be normally output, and when the second signal is at a low level, the voltage turn-off module is in a state of normally supplying power to the high voltage board, the second power 24vs_a for controlling the high voltage generation module can be normally output, which is not limited in the present application.

It is understood that the embodiment of the present application is only illustrated by taking the structure of the voltage shutdown module shown in fig. 2 as an example, and is not limited in any way.

In the embodiment of the present application, the detection of the abnormality of the high voltage generation module may be divided into a stage in which the image forming apparatus performs image formation (i.e., during image formation) and a stage in which the image formation is not performed (during non-image formation), and a specific manner of controlling the voltage shutdown module when the abnormality exists in the high voltage generation module and when the abnormality exists in the high voltage generation module will be described below.

Next, the detection of the abnormality of the high voltage generation module is the detection of the high voltage abnormality in the current high voltage circuit.

In the prior art, the period of high voltage abnormality detection is defined as the start of detection when the transfer voltage is on, and the end of detection when the transfer voltage is over.

However, since the transfer voltage of the A3 model image forming apparatus may vary, that is, there are a plurality of voltage terminals that continuously jump. Taking a black-and-white printer of model A3 for example, the transfer imaging sequence includes a plurality of specifications such as a cleaning negative pressure, a cleaning positive pressure, a transfer voltage before feeding paper, a transfer reading voltage, a transfer normal imaging voltage, and the like.

In addition, due to the specificity of the rear end load of the printer, the change of the load of the transfer roller along with the temperature is obvious, and when the voltage is increased due to the change of the load and the jump or overshoot of the voltage under the high temperature (or low temperature) condition, the false detection of the high-voltage alarm signal is easy to occur.

In the embodiment of the application, the problem of false detection of the high-voltage alarm signal is solved by correcting the detection time period of the high-voltage alarm. It is considered that the image forming apparatus is performing image formation, that is, the image forming apparatus is printing, the conveyance condition of the sheet can be detected by a sensor in the image forming apparatus. For example, the embodiment of the present application does not specifically limit the specific implementation of the paper sensor by a paper relay sensor (i.e., an image forming medium sensor), a paper discharge sensor, or the like.

The voltage shut-off module as in the above embodiment, the timing at which the image forming apparatus starts to perform image formation may be determined by detecting the conveyance condition of the sheet by a sensor in the image forming apparatus.

Taking the sensor as a paper relay sensor as an example, the detection of the transfer condition of paper by the paper relay sensor can be seen from fig. 3. Fig. 3 is a schematic diagram of detecting a paper position by a paper relay sensor according to an embodiment of the present application.

As shown in fig. 3, the paper relay sensor is ON in the start state when the paper relay sensor is at a low level, and is OFF in the OFF state when the paper relay sensor is at a high level. The paper relay sensor can be a photoelectric sensor, and when paper passes through the sensor, the light source is shielded, and a signal becomes low level to indicate that the head of the paper has entered; the sensor signal goes high from low, indicating that the sheet tail has left the sensor and has been ejected, and may be arranged to mask the light source as the sheet passes the sensor, the signal going high, indicating that the sheet head has entered; the sensor signal goes from high to low, which indicates that the sheet tail has left the sensor and has been ejected, which is not a limitation of the present application.

Fig. 4 is a schematic diagram showing a change of voltage of an image forming apparatus with time when performing an image forming process according to an embodiment of the present application.

In fig. 4, the image forming apparatus is not in the process of performing image formation when the sensor signal is at a high level, and is in the process of performing image formation when the sensor signal is at a low level.

In fig. 4, THV (Transfer High Voltage ) is used to represent a transfer voltage in performing image transfer. The image forming apparatus is in the process of performing image formation, and the transfer voltage is a transfer voltage used for normal image formation through a plurality of jumps of different voltage values, thv_1.

Since the thv_1 period voltage is most stable and also the duration of time that has elapsed is longest, the period in which the voltage becomes thv_1 (i.e., the detection period in fig. 4) is relatively suitable as the fault detection period in the steady state. And the THV_1 section voltage is constant, whether the overcurrent protection is triggered is only related to the back-end load, when the back-end load is smaller, the high-voltage overcurrent protection is easier to trigger, the time is selected for detection, and the influence of signal false detection caused by unstable jump or overshoot of the high-voltage is eliminated. As shown in fig. 4, the high-voltage abnormality detection may be started after a predetermined time Δtms elapses from the high-low of the signal of the paper relay sensor, and as described in the above embodiment, whether or not the abnormality exists in the high-voltage generation module may be detected by the detection module. When the signal of the paper relay sensor is reset from low to high, the abnormality detection of the high-voltage first signal hv_err is stopped, that is, the detection of the high-voltage fault is performed only for a period in which the transfer voltage is stable. That is, the detection of the first signal is started when the imaging medium detection sensor detects that the leading end of the imaging medium (e.g., paper) passes, the detection of the first signal is stopped when the trailing end of the imaging medium is detected to leave, and the detection of the first signal is started after a predetermined time delay when the imaging medium (e.g., paper) detection sensor detects the leading end of the imaging medium to perform the detection of the high-voltage abnormality.

In the embodiment of the present application, the predetermined time Δtms may be set according to the actual situation of the image forming apparatus, and in some cases, the predetermined time Δtms may be set to 0ms, 1ms, 2ms, or the like, which is not limited in the embodiment of the present application. The purpose of the delay time Δt is to exclude operations in other image forming aspects of the paper front-end white position, not a constant stable output image forming high voltage, and the false detection can be reduced by setting the delay time for a predetermined time.

In this embodiment of the present application, the high voltage protection device further includes a conversion module, where the conversion module is configured to receive an output value of the detection module, convert the output value, and feed back the converted output value to the control module.

The detection module may be, for example, a circuit that detects a current value.

The detection module is specifically configured to detect a current value output by the high-voltage generation module, and transmit the current value to the conversion module, where in some other possible schemes, the detection module may be further configured to detect a voltage and a power value output by the high-voltage generation module, and determine whether an abnormality occurs by comparing the output voltage and power value with predetermined values.

In one embodiment, the conversion module is configured to receive the output value of the detection module and level-convert the output value during image formation (i.e., during printing), and output a first signal to the first input interface of the control module through the first output terminal of the conversion module; or alternatively

The conversion module is used for receiving the output value of the detection module and converting the output value during the non-image forming period (namely after the image forming device is started or after the image forming operation is completed), outputting a high-voltage feedback value through a second output end of the conversion module, outputting the high-voltage feedback value to the analog-to-digital converter, converting an analog signal of the high-voltage feedback value into a digital signal through the analog-to-digital converter, and outputting the digital signal to a second input interface of the control module.

In order to cut off the output of the second power by different error-reporting codes using different control methods, it is necessary to use different high-voltage abnormality detection methods and to present by different fault codes during image formation and during non-image formation.

The image forming period refers to a stage in which various image forming high voltages (charging, developing, transfer high voltages, etc.) are turned on after a print job is issued.

The non-image forming period refers to a period in which the high voltage is not turned on after the image forming apparatus turns on the engine 24V and a period in which the high voltage is turned off after each print job ends.

Whether or not a high voltage abnormality occurs needs to be determined by the level state of the first signal (hv_err signal) during image formation, and specific steps of determining whether or not a high voltage abnormality occurs by the level state of the first signal during image formation will be described in detail below:

The control module is used for judging that the high voltage is abnormal and outputting a first fault code when a first signal output by the first output end of the conversion module is received and the first signal meets a first preset condition, and the first fault code is used for outputting an alarm signal by the image forming device.

The first preset condition is that the first signal is continuously detected as a level signal indicating that the high voltage generation module is abnormal, and an abnormal count value of the first signal is detected to be larger than a first preset value every first preset time in the image forming period.

For example, the image forming apparatus detects the level state of the first signal every a first preset time (for example, 10ms, it is understandably also set to 20ms, 30ms according to actual needs, which is not limited in the present application), for example, considers that a high voltage appears once when the first signal hv_err=l is detected, counts an abnormal value once, and when the abnormal count value is greater than the first preset value (for example, 5 times, it is understandably also set to 10 times, 15 times according to actual needs, which is not limited in the present application), considers that there may be a high voltage output abnormality in the present printing process and outputs a first fault code.

In addition, when a high-voltage abnormality is detected during image formation, the second power is cut off by the first control method, that is, by the gently-broken control method, that is, after the current print job is executed first, the second signal is switched to a level state corresponding to the high-voltage output abnormality (for example, the second signal is changed to a low level first) while the output of the second power is turned off.

Whether or not a high voltage abnormality occurs needs to be determined by means of the relationship between a high voltage feedback value (e.g., mhv_read, thv_read, i.e., a charge high voltage READ value, a transfer high voltage READ value) and a reference value during non-image formation, and specific steps for determining whether or not a high voltage abnormality occurs by means of the relationship between a high voltage feedback value and a reference value during non-image formation will be described in detail below:

And when the number of the high-voltage feedback values detected every second preset time in the non-image forming period is the second preset value, calculating the average value of the high-voltage feedback values, wherein the average value is larger than or equal to a third preset value.

For example, the image forming apparatus detects the high-voltage feedback values every second preset time (for example, 10ms, it is understood that the high-voltage feedback values may be set to 20ms or 30ms according to actual needs) during non-image forming (for example, after the current job is printed), and when the number of the read high-voltage feedback values is the second preset value (for example, 30, it is understood that the high-voltage feedback values may be set to 40 or 50 according to actual needs), the read values of the read 30 feedback signals are calculated and averaged, and then compared with the third preset value (the reference value, it is understood that the reference value of the read value of the MHV and the reference value of the THV may be set to det1_ref or det2_ref, respectively), and when the calculated average value is greater than or equal to the third preset value, it is considered that the high-voltage abnormality may occur, and the second fault code is output. A READ value > DET _ REF, for example, of the average value, considers that an uncontrolled abnormal fault occurs in the high voltage, enters the fault handling phase of "off-state", and shuts down the second power.

Further, when a high voltage abnormality is detected during non-image formation, the second power is cut off by the second control method, that is, the second power is cut off by the immediately-cut control method, and the output of the second power is directly turned off.

Further, the high voltage protection device further comprises an Analog-to-Digital Converter (ADC for short), wherein a second output end of the conversion circuit is connected to a first end of the Analog-to-digital converter, a second end of the Analog-to-digital converter is connected to the control module through a second input interface of the control module, and the Analog voltage signal is converted into a digital voltage signal through the Analog-to-digital converter and then transmitted to the control module.

In the above embodiment, the conversion circuit outputs the high-low level signal of the first signal to the control module during the image forming period or converts the detected current into the analog voltage through the internal components such as the operational amplifier during the non-image forming period and outputs the analog voltage to the analog-digital converter, so that the control module performs the high-voltage abnormality judgment based on the values input by the two different input terminals, and the reason of the failure of the image forming device in each stage can be more favorably distinguished for the purpose of problem analysis and maintenance positioning.

As described in connection with the above embodiments, the structure of the high voltage protection device provided in the embodiment of the present application may be shown in fig. 5. Fig. 5 is a schematic structural diagram of another high-voltage protection device according to an embodiment of the present application.

As shown in fig. 5, the protection circuit may include a power module, a voltage shutdown module, a high voltage generation module, a detection module, a control module, a conversion module, and an analog-to-digital converter. The above modules are provided in a data plate and a high-pressure plate of the image forming apparatus, respectively. The control module and the analog-to-digital converter are arranged in a data board (namely a control board and a main control board), and the voltage turn-off module, the high voltage generation module, the detection module and the conversion module are arranged in a high voltage board.

The power panel (i.e. the power supply module) generates 24V power and obtains first power (i.e. the engine 24V) through MOS tube conversion in the main control panel (i.e. the data panel), the obtained first power is supplied to the voltage turn-off module and the laser scanning unit, the fan, the motor and other modules through the MOS tube, the MOS tube can be set as an NMOS tube or a PMOS tube, and other devices capable of realizing the switching effect can be set as understood MOS tubes, and the application is not limited in this respect.

The functions of the modules may be described in the above embodiments, and are not described herein.

In order to facilitate understanding of the high voltage protection device provided in the embodiment of the present application, a method for determining a high voltage abnormality during image formation and during non-image formation by the voltage shutdown module in the embodiment of the present application will be described below with reference to a circuit configuration shown in fig. 6.

The following describes a control method of the image forming apparatus for performing high-voltage abnormality determination during image formation, and fig. 6 is a schematic flow chart of a control method according to an embodiment of the present application.

As shown in fig. 6, the control method may include the steps of:

s601, high voltage abnormality detection by the image forming apparatus during the image forming period is started.

In the embodiment of the present application, when the delay predetermined time Δt is exemplified by 0, the timing at which the high-voltage abnormality detection is started is the timing at which the image forming apparatus starts executing the image formation for the first preset time. When the first preset time is 2 seconds, the timing at which the high-voltage abnormality detection is started is the timing 2 seconds after the image forming apparatus starts to perform image formation.

S602, the control module reads and acquires a first signal through the first input interface every a first preset time.

The first preset time may be 10ms or 20ms, which is not limited in this embodiment of the present application.

For example, the manner in which the control module obtains the first signal through the first input interface may be described in the above embodiments, which is not described herein.

S603, judging whether the first signal is a low level signal.

When the first signal is a low level signal, the following step S604 may be performed, and when the first signal is a high level signal, the following step S602 may be performed.

S604, updating the original abnormal count value according to the acquired low-level signal to obtain a new abnormal count value.

For example, a specific value may be added to the original anomaly count value every time a low level is detected, for example, 1 may be added to the original anomaly count value every time a low level is detected, so as to obtain a new anomaly count value. For example, when the original anomaly count value is 3, the updated anomaly count value may be 4.

S605, judging whether the new abnormal count value is larger than or equal to a first preset value.

The first preset value may be a value set according to an actual situation, which is not limited in the embodiment of the present application.

When the new abnormality count value is greater than or equal to the first preset value, step S606 described below is performed, and when the new abnormality count value is less than the first preset value, step S602 may be performed.

S606, the control module executes a slow break mechanism, and the voltage turn-off module turns off the second power.

For example, the second power is turned off by the slow break mechanism after detecting whether the image forming apparatus has finished forming the image, which can be determined by the signal transmitted by the paper relay sensor in the above embodiment, which is described in the above embodiment and will not be described here again.

Since the image forming process has the participation of the developer, after the error is detected in the image forming process, the second power (24vs_a) can be turned off after the control module voltage turn-off module outputs the low-level second signal to reduce the abnormal scattering of the developer by executing the slow-break mechanism, i.e. after the image forming device completes the current printing task.

S607, a first fault code is generated.

Illustratively, the first fault code is generated based on an operating state of the image forming apparatus at the occurrence of the abnormality. The image forming apparatus may output the first trouble code so that a serviceman can determine the cause of the abnormality by the first trouble code output by the image forming apparatus, for example, the first trouble code may be represented by fe_1.

The following describes a control method for determining high-voltage abnormality during non-image formation by an image forming apparatus, and fig. 7 is a schematic flow chart of another control method according to an embodiment of the present application.

As shown in fig. 7, the control method may include the steps of:

s701, high voltage abnormality detection by the image forming apparatus during a non-image forming period is started.

S702, the control module acquires analog voltage signals through a second input interface every second preset time.

For example, when the control module acquires the voltage signals through the second input interface at every second preset time, the control module may continuously acquire a plurality of voltage signals at every second preset time.

S703, judging whether the data times of the acquired analog voltage signals reach a second preset value.

When the number of data of the acquired analog voltage signal reaches the second preset value, step S704 described below may be performed, and when the number of data of the acquired analog voltage signal does not reach the second preset value, step S702 may be performed.

S704, calculating an average value of the acquired analog voltage signals.

S705, judging whether the average value is larger than or equal to a third preset value.

Step S706 may be performed when the average value is greater than or equal to the third preset value, and step S708 may be performed when the average value is less than the third preset value.

S706, the control module executes an instant-off mechanism, and the voltage shutdown module shuts down the second power.

S707, generating a second fault code.

Illustratively, the second fault code is generated based on an operating state of the image forming apparatus at the occurrence of the abnormality. The image forming apparatus may output the second trouble code so that a serviceman can determine the cause of the abnormality by the second trouble code output from the image forming apparatus, for example, the second trouble code may be represented by fe_2.

S708, ending the detection.

Since the image forming process in the non-image forming period in which printing is not performed does not involve the developer, the second power (24vs_a) can be directly turned off by directly employing the instant off mechanism after detecting an error in the non-image forming period.

In the embodiment of the present application, the specific cause of occurrence of the high-voltage abnormality is determined by the content and the number of the trouble codes output from the image forming apparatus after the printing is completed. The high-voltage fault detection during non-image formation is mainly used for checking whether the high-voltage output is not controlled by firmware, namely, the abnormal state of hardware out of control, and closing the second power to stop the high-voltage output when out of control, so that the damage of the powder box drum assembly and the elements of the high-voltage plate caused by long-time output of the high-voltage can be avoided. In the fault detection of the non-printing stage, the firmware mainly READs the feedback READ value of the high-voltage board in the high-voltage non-opening state through the control module, wherein the feedback READ value comprises the charging and transfer high voltage, and gives a reference value of the charging and transfer feedback READ value.

As described in connection with the above embodiment, when a high-voltage abnormality is detected during image formation, it is determined that there is a possibility of a high-voltage abnormality in the current printing, and a graceful shutdown error reporting mechanism is performed. And when the high voltage is detected to be abnormal in the non-image forming period, switching the second signal to a low level and then closing the output of the second power and outputting the first fault code FE_1, and when the high voltage is detected to be abnormal in the non-image forming period, switching the second signal to a low level and then closing the output of the second power and outputting the first fault code FE_1 and the second fault code FE_2.

In summary, the comparison of the first fault code and the second fault code generated by the image forming apparatus can be seen in table 1 below.

TABLE 1

The image forming apparatus performs FE (i.e., error) protection triggered by high voltage during printing, and there may be two trigger conditions, one is that the high voltage board is not abnormal, the back end load impedance becomes extremely low, causing the high voltage output to be abnormally high in the constant voltage mode, and triggering protection; the other is that the load impedance is not abnormal, the high voltage plate is damaged to cause abnormal ultra-high voltage output, and the voltage exceeding a preset value is supplied to the back end load to cause overcurrent protection.

Both cases do not allow the user and the printer maintenance personnel to make an accurate judgment at the first time of occurrence of the problem, and have adverse effects on positioning of the component of the image forming apparatus where the problem occurs and subsequent analysis of the cause of occurrence of the abnormality. In the embodiment of the application, through the high-voltage abnormality detection during the image forming period and the non-image forming period, different specific fault conditions are distinguished by the alarm of two fault codes, and the specific description can be seen in the following table 2.

TABLE 2

Based on the contents of table 2, it is possible that the high-pressure board has already suffered a hardware damage if both failures (fe_1 and fe_2) occur at the same time after the failure detection before image formation and during non-image formation. When only the code of fe_1 is present, the cause of the failure may be a change in the back-end load. Therefore, the purpose of accurately positioning the problem component can be achieved by distinguishing whether the fault is mechanical or electrical on the high-voltage board through the content of the fault code.

As shown in table 3 below, whether or not a high-voltage abnormality occurs can be determined by detecting a high-voltage feedback value and determining the relationship between the high-voltage feedback value and a reference value during non-image formation, examples of which are as follows.

TABLE 3 Table 3

Feedback signal	Judgment reference	Numerical value
			MHV_READ	DET1_Ref	0.4
THV_READ	DET2_Ref	0.3

In summary, the protection circuit provided by the embodiments of the present application has at least one or more of the following advantages:

1. according to the high-voltage protection device, when the image forming device is subjected to high-voltage abnormal protection, the voltage shutdown module can be controlled to be in a closed state, so that abnormal output is prevented by only shutting off the voltage of the high-voltage plate, and power supply of other hardware modules powered by the engine 24V is not affected.

2. The detection period of overcurrent protection in printing is set based on the paper relay sensor signal, so that the voltage is constant during overcurrent detection, whether the load reaches a protection reference or not can be accurately measured, false detection caused by voltage disturbance is avoided, and the detection accuracy is improved. The condition that the high-voltage alarm is frequently triggered to influence the use of a user can be reduced, and the user experience is improved.

3. Through the slow breaking mechanism, the condition that the printing is interrupted to cause the scattering of the developer is reduced, namely, a high-voltage loop is protected, the service life of a consumed powder cylinder load is reduced, and the abnormal loss of the service life of the powder box is reduced. Through combining alarm detection logic, the abnormal reasons of high-voltage error reporting in printing can be clearly determined through error reporting codes and quantity, and the problem analysis and maintenance positioning of maintenance personnel are facilitated.

In another embodiment, during operation of the image forming apparatus, there may occur a phenomenon that an output current is excessively large or an output power is excessively large, which may not only affect a currently printed image but may damage a circuit of the image forming apparatus, which may reduce a lifetime of the image forming apparatus. The image is adversely affected, and if these conditions occur for a long period of time, the circuit is damaged, which causes an irreversible effect on the printer. In the high-voltage protection circuit provided by the embodiment of the application, a module for protecting the high-voltage circuit can be further provided. As shown in fig. 8. Fig. 8 is a schematic structural diagram of still another high voltage protection circuit according to an embodiment of the present application.

As shown in fig. 8, the high-voltage protection circuit includes circuit modules such as a power detection circuit, an output current detection circuit, a current feedback circuit, an abnormality detection circuit, a fault feedback circuit, a hardware protection circuit, and an operational amplifier protection circuit.

Where VOUT user represents the load of the image forming apparatus. The control signal may be a voltage shutdown module as described in the above embodiments.

As shown in fig. 8, the input end of the power detection circuit is connected between the output of the operational amplifier circuit and the input of the high voltage generation module, the input end of the output current detection circuit is connected with the output end of the load VOUT, the output end of the power detection circuit is connected with the input end of the abnormality detection circuit and the input end of the current feedback circuit, the output end of the output current detection circuit is connected with the input end of the abnormality detection circuit and the input end of the current feedback circuit, the output end of the abnormality detection circuit is connected with the input end of the hardware protection circuit and the input end of the fault feedback circuit in a decibel manner, and the output end of the fault feedback circuit is connected with the input end of the control module. The output end of the current feedback circuit is connected with the input end of the ADC. The input end of the operational amplifier protection circuit is connected with the output end of the control signal.

Next, the operation of each circuit module will be described.

As shown in fig. 9, the power detection circuit is disposed at the output end of the op-amp circuit, and the op-amp protection circuit is mainly used for comparing the voltages at the input ends thereof, driving the oscillating circuit, and regulating the output high voltage. Since the voltage value output by the operational amplifier circuit determines the magnitude of the transformer converted power, and the power converted by the transformer also determines the magnitude of the output power of the load, the voltage value output by the operational amplifier circuit can be used for judging the magnitude of the output power of the load. When the operational amplifier output voltage value becomes high, the output power of the load also becomes large, and thus the range of the output power of the load can be controlled by controlling the range of the voltage value output by the operational amplifier.

Fig. 9 is a schematic diagram of a result including a power detection circuit according to an embodiment of the present application.

As shown in fig. 9, the power detection circuit may include a zener diode ZD1, a diode D1, a resistor R6, and a capacitor C5. One end of the zener diode ZD1 is connected to the output end of the operational amplifier circuit, the other end of the zener diode ZD1 is connected to one end of the resistor R6, the other end of the resistor R6 is respectively connected to one end of the diode D1 and one end of the capacitor C5, the other end of the diode D1 is connected to the abnormality detection circuit, and the other end of the capacitor C5 is grounded.

As shown in fig. 9, when the power output by the load is larger, the voltage value output by the op-amp is larger, and when the output voltage value is larger than the reference voltage of the zener diode ZD1, the zener diode ZD1 is in a conducting state, at this time, the diode D1 is conducted, and the diode D1 can output a power abnormality signal to the abnormality detection circuit.

The embodiment of the present application will be described by taking the result of the power detection circuit shown in fig. 9 as an example only, and is not limited in any way.

In the present embodiment, the output current detection circuit may include two possible implementations as shown in fig. 10 and fig. 11.

In one possible implementation, the output current detection circuit needs to feed back the output current value to the control module, where the output current detection circuit may be as shown in fig. 10, and fig. 10 is a schematic circuit structure diagram of the output current detection circuit according to the embodiment of the present application.

As shown in fig. 10, the input current detection circuit may include a resistor R7, a resistor R8, a resistor R9, a resistor R10, a resistor R11, a resistor R12, a resistor R13, a capacitor C6, a diode D2, and a comparator U1A. The output terminal VOUT in fig. 10 is an input terminal of the load.

The capacitor C6 may be a high-voltage capacitor, and is used for storing energy. R7 is the current limiting resistor of the output.

As shown in fig. 10, one end of a resistor R7 is connected to the input end of the load, the other end of the resistor R7 is connected to the output end of the feedback circuit, one end of the high voltage generation module and one end of the capacitor C6, the other end of the feedback circuit is connected to the first end of the comparator U1B, the second end of the comparator U1B is connected to the output end of the input circuit, and the third end of the comparator U1B is connected to the other end of the high voltage generation module. The other end of the capacitor C6 is connected with one end of a resistor R10, the other end of the resistor R10 is connected with one end of a resistor R9, one end of a resistor R11, one end of a resistor R8 and the first end of a comparator U1A, the other end of the resistor R9 is connected with the output end of the feedback circuit, and the other end of the resistor R11 is grounded. The second end of the comparator U1A is connected with one end of the resistor R12 and one end of the resistor R13, and the other end of the resistor R12 and the other end of the resistor R13 are grounded. The third terminal of the comparator U1A is connected with the other end of the resistor R8, the input end of the current feedback circuit and one end of the diode D2, and the other end of the diode D2 is connected with the input end of the abnormality detection circuit.

In fig. 10, I2 is the output current of the high-voltage load, and the current loop is the arrow path in the figure: GND→VCC→I6→I1→I2→GND. From this loop it is seen that current flows through resistor R8 to generate a certain voltage, and as the output current is greater, the voltage drop across R8 is greater. The current I6 flowing through R8 thus reflects the magnitude of the output current, and the relationship between I6 and output current is i6+i4=i1+i5=i3+i2+i5, as shown in fig. 10, i4=i3, and thus i6=i2+i5 can be found.

Because of the weak-short characteristic of the op-amp, the voltages at pins 2 and 3 of the comparator U1A are the same, so the current I5 is a fixed value, and the current value of I5 may be i5=vref/R11, and thus i6=i2+i5=i2+vref/R11.

The current I6 is transmitted to the ADC through the current feedback circuit, and then is transmitted to the control module SOC through the ADC. Illustratively, when the output current value is greater than a preset threshold, the diode D2 is turned on, outputting a current abnormality signal to the abnormality detection circuit. The preset threshold may be set by the abnormality detection circuit, for example, may be set by a conduction current of hardware inside the abnormality detection circuit, which is not limited in the embodiment of the present application.

In another possible implementation, the output current detection circuit does not need to feed back the output current value to the control module, and the output current detection circuit may be as shown in fig. 11, where fig. 11 is a schematic circuit structure diagram of another circuit including the output current detection circuit according to the embodiment of the present application.

As shown in fig. 11, the output current detection circuit may include a resistor R14, a resistor R15, a capacitor C7, a capacitor C8, and a diode D3.

As shown in fig. 11, one end of the resistor R14 is connected to the input end of the load, the other end of the resistor R14 is connected to the high voltage generation module and one end of the capacitor C7, the other end of the capacitor C7 is connected to one end of the resistor R15, one end of the resistor R16 and one end of the diode D3, both the other end of the resistor R15 and the other end of the resistor R16 are grounded, and the other end of the diode D3 is connected to the abnormality detection circuit.

The capacitor C7 may be a high-voltage capacitor, and is used for storing energy. The capacitor C8 is a filter capacitor. R14 is the current limiting resistor of the output.

In fig. 11, the current I1 is the output load current, and the current loop corresponds to the red arrow path in the figure: GND-I7-I8-GND, the current flowing through the resistor R15 is equal to the output current, the voltage drop on the resistor R15 is larger when the output current is larger, the diode D3 is conducted when the output current value is larger than a preset threshold value, and an output current abnormality signal is transmitted to an abnormality detection circuit. The preset threshold may be set by the abnormality detection circuit, for example, may be set by a conduction current of hardware inside the abnormality detection circuit, which is not limited in the embodiment of the present application.

Fig. 12 is a schematic circuit diagram of a circuit structure including a current feedback circuit according to an embodiment of the present application.

As shown in fig. 12, the current feedback circuit is composed of a resistor R16, a resistor R17, a capacitor C9, and a zener diode ZD 2.

The output end of the output current detection circuit is connected with one end of a resistor R17 and one end of a zener diode ZD2, the other end of the resistor R17 is connected with one end of a capacitor C9, one end of a resistor R16 and the input end of the ADC, and the other end of the resistor R16, the other end of the capacitor C9 and the other end of the zener diode ZD2 are grounded.

As shown in fig. 12, the output current feedback circuit transmits the output current to the ADC for determining whether the output current is excessively large or for distinguishing an environment to which the printer belongs for configuring the printing voltage, and when the image forming apparatus is in a high temperature state, the bar resistance of the image forming apparatus is reduced, the output current is increased, and when the image forming apparatus is in a low temperature state, the bar resistance is increased, and the output current is reduced.

As shown in fig. 12, the zener diode ZD2 is used to limit the magnitude of the voltage value transferred to the SOC through the ADC, avoid the feedback voltage from being too high to damage the SOC pins in abnormal situations (such as low load), C9 performs filtering, and the resistor R16 and the resistor R17 are used to configure the range of the current value collected by the ADC.

Fig. 13 is a schematic circuit diagram of a circuit structure including an abnormality detection circuit according to an embodiment of the present application.

As shown in fig. 13, the abnormality detection circuit may include a resistor R18, a resistor R19, a resistor R20, a resistor R21, a resistor R22, a capacitor C10, a diode D4, and a comparator U1C.

The output end of the output current detection circuit is connected with one end of a resistor R19, the other end of the resistor R19 is connected with the output end of the power detection circuit, one end of a resistor R18 and one end of a resistor R20, the other end of the resistor R18 is connected with the third end of a comparator U1C and one end of a capacitor C10, and the other end of the capacitor C10 and the other end of the resistor R20 are grounded. The first end of the comparator U1C is connected with one end of the diode D4, and the other end of the diode D4 is connected with the output end of the fault feedback circuit and the input end of the hardware protection circuit. The second end of the comparator U1C is connected with one end of the resistor R21 and one end of the resistor R22, the other end of the resistor R22 is grounded, and the other end of the resistor R21 is connected with voltage.

Wherein, R18 plays an isolating role, C10 plays a filtering role, the threshold value of the output current can be configured by setting the values of R19, R20 and Vref, and the threshold value of the power detection can be configured by configuring the value of Vref and the turn-on voltage of the zener diode ZD1 in fig. 12. The embodiments of the present application are not limited in this regard.

Illustratively, in fig. 13, when an abnormal signal from the power detection circuit or the output current detection circuit is received, the current flowing through the resistor R20 is larger and larger, and when the voltage drop of the resistor R20 is larger than Vref, the comparator U1C outputs a high level, which is transferred to the fault feedback circuit and the hardware protection circuit; when the power supply works normally, the power current is normal, the voltage drop of the resistor R20 is smaller than Vref, and the comparator U1C outputs a low level.

Fig. 14 is a schematic circuit diagram of a circuit structure including a fault feedback circuit according to an embodiment of the present application.

As shown in fig. 14, the fault protection circuit may include a resistor R23, a resistor R24, a resistor R25, and a transistor Q1. The output end of the abnormality detection circuit is connected with one end of a resistor R24, the other end of the resistor R24 is connected with one end of a resistor R25 and the first end of a triode Q1, and the second end of the triode Q1 and the other end of the resistor R25 are grounded. The third end of the triode Q1 is connected with one end of a resistor R23 and the input end of the control module, and the other end of the resistor R23 is connected with the voltage VCC1.

As shown in fig. 14, when the high level of the abnormality detection circuit is received, the transistor Q1 is turned on, the fault feedback signal hv_abs is pulled low, and the fault feedback circuit outputs a low level. During normal operation, the triode Q1 is not conducted, the fault feedback signal HV_ABS is pulled to a high level by the pull-up resistor R23, and the fault feedback circuit outputs a high level.

When the control module SOC receives a low level, namely, the abnormal conditions such as overlarge output current or output power occur on the high-voltage board at the moment, the abnormal conditions can be eliminated by controlling the PWM signal to reduce the output voltage through the firmware, or the user is warned of internal faults of the printer through the panel. The PWM signal is a signal that the control module transmits to the high voltage generating module, which is not limited in this embodiment of the present application.

Fig. 15 is a schematic circuit diagram of a circuit structure including a hardware protection circuit according to an embodiment of the present application.

As shown in fig. 15, the hardware protection circuit may include a resistor R26, a resistor R27, a resistor R28, a resistor R29, a resistor R30, a resistor R31, a capacitor C11, a diode D5, a transistor Q2, and a transistor Q3.

As shown in fig. 15, the first end of the comparator U1B is connected to one end of the diode D5, the other end of the diode D5 is connected to one end of the resistor R26, the other end of the resistor R26 is connected to one end of the resistor R27 and the first end of the transistor Q2, the other end of the resistor R27 is grounded, the second end of the transistor Q2 is connected to the voltage VCC1 and to one end of the resistor R28, and the other end of the transistor Q2 is connected to the other end of the resistor R28 and one end of the resistor R29. The third end of triode Q3 is connected to the other end of resistance R29, and the one end of electric capacity C11 is connected to the first end of triode Q3, the one end of resistance R30 and the one end of resistance R31, and the second end of triode Q3, the other end of electric capacity C11, the other end of resistance R31 all ground connection, and the output of anomaly detection circuit is connected to the other end of resistance R30.

In this embodiment of the present application, the hardware protection circuit shown in fig. 15 may be used in both cases of excessive current and excessive power, where the power detection and the output current detection share the same hardware protection circuit, and the abnormality detection circuit drives the hardware protection circuit to work after outputting a high level no matter the power is excessive or the output current is excessive. The hardware protection circuit can be shared by single or multiple groups of high voltages, and each branch circuit can be protected simultaneously when one branch circuit sharing one protection circuit has overlarge power or overlarge current.

For example, when the output power or the output current is larger and larger, the abnormality detection circuit outputs a high level, the current flows through R31 and R30, when the G pole voltage of Q3 is larger than the on voltage, Q3 is turned on, D pole is pulled down, Q2 is turned on, R26 is connected to the inverting input terminal of the op-amp through D4, at this time, the inverting input terminal (6 pins) is pulled up, the op-amp has no output, and each path of high voltage also stops outputting, thereby realizing the protection function. When each path of high voltage normally works and the output power and the output current do not reach the protection point, the abnormality detection circuit outputs a low level, Q3 is cut off, Q2 is cut off, and each path of voltage normally works.

Therefore, under abnormal conditions, the abnormal conditions can be eliminated through firmware protection and hardware protection, in order to enable the firmware to be adjusted first, a delay circuit (R30 and C11) is arranged in the hardware protection circuit, so that signals are fed back to the firmware first when the firmware fails, after the firmware is adjusted for a period of time, if the adjustment is successful, the hardware protection is not needed, and if the adjustment fails, the hardware circuit is protected, and therefore the experience of a user is better improved.

Although the output current feedback circuit also feeds back the output current to the SOC, the signal uses an ADC acquisition mode, and the current mainly functions to judge the environment to determine the size of the paper feeding voltage. However, when the current feedback value is high, the signal acquired by the ADC is inaccurate, and it may not be possible to determine whether the allowable output maximum current is exceeded. The fault feedback signal HV_ABS can feed back two abnormal conditions of overlarge current and overlarge output power at the same time.

Fig. 16 is a schematic diagram of a circuit structure including an op-amp protection circuit according to an embodiment of the present application.

As shown in fig. 16, the operational amplifier protection circuit is disposed at an input end of the operational amplifier, and the operational amplifier protection circuit may include a resistor R32, a diode D6, and a diode D7.

One end of the diode D6 is connected to the first end of the comparator U1B, the other end of the diode D6 is connected to one end of the resistor R32 and one end of the diode D7, the other end of the resistor R32 is connected to the voltage VCC1, and the other end of the diode D7 is grounded.

In this embodiment of the present application, since the voltage specification range of the input end of the op-amp may be greater than or equal to-0.3V, when the high voltage is turned off, the in-phase input end undershoots, and when the voltage of the in-phase input end is less than-0.3V, the op-amp may have a phenomenon of failure in regulation, i.e., the op-amp cannot be turned off, and outputs the maximum value, and then the high voltage also outputs the maximum value, and cannot turn off the high voltage.

When the high voltage is controlled to be turned off, the PWM control signal is at a low level, after the PWM control signal is at a low level, the high voltage is turned off in a very short time after the operational amplifier is turned off, but because of the time difference between the PWM control signal at the low level and the operational amplifier which is turned off, when the PWM signal is turned off, the feedback loop is still turned on, and then V2 is negative pressure. The higher the voltage output before the high voltage is turned off, the smaller the negative voltage of V2 at the time of turning off.

Illustratively, in normal operation, V2 > 0V, v1=vcc 1, and assuming a diode turn-on voltage drop of 0.7V, then D7 is turned on and V1 is clamped at 0.7V and D6 is turned off. When V2 is less than or equal to 0V, the voltage drop at the two ends of D6 is more than or equal to 0.7V, D6 is conducted, and V2 is clamped at 0V, so that the V2 is not negative pressure, and the operational amplifier is not invalid.

When the high voltage is turned off, since the protection circuit clamps V7 at 0V, V1 and the input voltage are both 0V, no current flows through the feedback loop and the high voltage is also turned off.

In this way, a high-voltage protection circuit is built in a low-cost mode, so that the circuit is not damaged under the condition of circuit abnormality caused by load abnormality and the like, and in addition, multiple fault signals can share one path of abnormality detection, hardware protection circuits and fault feedback resistors, so that operational amplifier and pin resources can be saved.

In addition, in order to improve user experience, when abnormality occurs, firmware voltage reduction processing can be performed first to eliminate faults, if no faults exist, printing can be continued, the quality of printed images is guaranteed, hardware protection is performed until firmware control cannot eliminate control, and multiple protection is achieved.

In addition, since in the prior art, the detection method for the imaging component and the high voltage generally needs to rely on the printed image effect or use a practical tool, such as a high voltage rod, an oscilloscope can acquire whether the imaging component and the high voltage are abnormal.

The scheme that this application was implemented and is provided can realize automated inspection imaging module and charge, develop, the state of primary transfer high pressure. The scheme is not limited to being applied to the occasions of engine routine self-checking, maintenance modes and the like. The detection imaging assembly may include an organic photoconductor (Organic Photoconductor, OPC for short), a development assembly, etc., and embodiments of the present application are not limited.

The embodiment of the application can detect through feedback voltage, color correction concentration, carbon powder concentration sensor voltage value, OPC surface potential can detect the abnormality of imaging component more quickly, for example, the pressure difference between the photosensitive drum and the developing roller is not in a reasonable range, OPC surface is damaged, charging high voltage is abnormal, developing high voltage is abnormal, primary transfer high voltage is abnormal and the like, user abnormal information is timely reminded, and user experience is improved. Meanwhile, each path of high voltage can be adjusted according to the corresponding abnormality, the detection of color correction concentration is matched, the detection of the voltage value of the carbon powder concentration sensor is realized, the high voltage configuration of charging and developing is controlled more accurately, the dispersion of the carrier and the carbon powder is prevented, and the image quality is improved.

First, referring to fig. 17 for an internal structure of an image forming apparatus according to an embodiment of the present application, fig. 17 is a schematic diagram of a part of an internal structure of an image forming apparatus according to an embodiment of the present application.

As illustrated in fig. 17, the image forming apparatus may include a transfer roller, a developing roller, OPC-M, and a charging roller. Wherein, the transfer roller can be used for feedback voltage detection, the developing roller can be used for carrying out the detection point detection of carbon powder concentration sensor, OPC-M (Organic Photoconductor, magenta photosensitive drum) can be used for carrying out OPC surface point position detection, and the charging roller can be used for feedback voltage detection.

In the embodiment of the application, after the image forming apparatus turns on the charging high voltage, a potential within a fixed range is generated on the OPC surface. When the difference between the OPC and the developing roller is kept at the N value, the electric field is balanced with the magnetic field of the developing roller, the carrier cannot fly at the moment, and carbon powder cannot be adsorbed to the non-exposure position of the OPC surface under the action of the electric field. When the image is printed, the normal carbon powder amount consumed by printing can be predicted according to the content of the printed image.

By way of example, the process of performing printing by the image forming apparatus may include the steps of:

and step 1, in a high-voltage unopened stage, performing abnormality detection.

In an exemplary high voltage unopened stage, high voltage fed back by the ADC is detected, and if a certain path of the acquired ADC data [ A0, A1] is out of the range, it may be determined that a certain path of high voltage is abnormally opened, and abnormality reporting is performed.

The high voltage fed back by the ADC is detected, and the collected data can be detected and filtered for multiple times, so that the high voltage fed back by the ADC is detected.

And step 2, in a high-voltage starting stage, performing abnormality detection.

This step may include the steps of:

and step 21, issuing a print job. The print job may be a print photo, print text content, or a combination of photo and text, and the embodiments of the present application do not limit the content of the print job.

Step 22, charging is started according to a preset time sequence, and the high voltage and the assembly are developed.

And step 23, charging into a detection voltage stage according to the time sequence, and performing ADC detection on the high voltage fed back by the ADC. And determining whether the acquired ADC data is within [ A0, A1], and if the acquired ADC data is within the interval, judging that the charging high voltage is not exerted, reporting an abnormality. Otherwise, the data collected by the ADC and the compensation value corresponding to the service life of the imaging component and the number of printing pages can be matched to obtain a new high-voltage adjustment value.

Step 24, charging the input adjustment value, performing a round of ADC detection, determining whether the acquired ADC value is within a section [ B0, B1], and if the acquired ADC value is within the section, determining that the high voltage is the current working voltage.

And step 25, if the acquired ADC data is not in the interval [ B0, B1], adjusting the compensation value, acquiring a new high-voltage value, acquiring the ADC data again after execution, and determining that the charging high-voltage output is abnormal if the ADC data is not in the interval [ B0, B1] three times continuously.

And step 26, starting the developing high voltage according to the time sequence, wherein the voltage value of the carbon powder concentration sensor is detected before the exposure, the exposure is not performed at the moment, no carbon powder and no carrier are consumed under normal conditions, and whether the developing voltage value is abnormal or not can be judged by detecting the voltage value of the carbon powder concentration sensor.

And step 3, after the exposure of the laser scanning unit, starting OPC surface potential detection and primary and secondary transfer detection.

The charging can be obtained through the step 2, whether the development is in a normal state or not is determined, the OPC surface potential detection is carried out at the moment, and the damage condition of the OPC can be obtained through potential change generated by charging and discharging.

After the exposure of the laser scanning unit, the primary transfer printing and the detection voltage of the secondary transfer printing are successively started, and whether the primary transfer printing and the secondary transfer printing are abnormal or not is detected according to the method in the step 2.

The embodiment of the application also provides an image forming device, which can comprise any one of the technical schemes described in the embodiment.

Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present application, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some or all of the technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A high-voltage protection device comprises a control module and a high-voltage generation module; the high-voltage generation module is used for generating high voltage; the control module is used for controlling the output of the first power; the high-voltage protection device is characterized by further comprising: the device comprises a detection module and a voltage turn-off module;

2. The high voltage protection device of claim 1, wherein the control module is further configured to begin detecting the first signal when the imaging media detection sensor detects that the leading end of the imaging media passes, and to cease detecting the first signal when the trailing end of the imaging media is detected to be away.

3. The high voltage protection device of claim 2, wherein the control module is further configured to begin detecting the first signal after a predetermined time when the imaging medium detection sensor detects a front end delay of the imaging medium.

4. The high voltage protection device according to claim 1, wherein the second signal is high when the high voltage output is normal and outputs low when the high voltage output is abnormal; or alternatively

5. The high voltage protection device of claim 1, wherein the control module is further configured to cut off the second power by a first control mode when a high voltage abnormality is detected during image formation.

6. The high voltage protection apparatus according to claim 5, wherein the first control mode is specifically to execute printing of a current image forming job first, switch the second signal to a level state corresponding to an abnormality in high voltage output after execution is completed, and shut off the output of the second power.

7. The high voltage protection device of claim 1, wherein the control module is further configured to cut off the second power by a second control mode when a high voltage abnormality is detected during non-image formation.

8. The high voltage protection device according to claim 7, characterized in that the second control means is in particular a direct shut-off of the output of the second power.

9. The high voltage protection device according to claim 1, further comprising a conversion module, wherein the conversion module is configured to receive the output value of the detection module, convert the output value, and feed back the converted output value to the control module.

10. The high voltage protection apparatus according to claim 9, wherein the conversion module is configured to receive an output value of the detection module and level-convert the output value during image formation, and output the first signal to a first input interface of the control module through a first output terminal of the conversion module; or alternatively

11. The high voltage protection device according to claim 10, wherein the control module is configured to determine that an abnormality occurs in the high voltage and output a first fault code when the first signal output by the first output terminal of the conversion module is received and the first signal satisfies a first preset condition, the first fault code being used for the image forming device to output an alarm signal; or alternatively

12. The high voltage protection apparatus according to claim 11, wherein the first preset condition is that the first signal is continuously detected as a level signal indicating that there is an abnormality of the high voltage generation module and an abnormality count value of the first signal is detected to be greater than a first preset value every first preset time during an image forming period; or alternatively

13. An image forming apparatus comprising the high voltage protection apparatus according to any one of claims 1 to 12.