JP7354579B2 - Image forming device and electromagnetic actuator driving method - Google Patents

Description

The present invention relates to an image forming apparatus and an electromagnetic actuator driving method.

2. Description of the Related Art A plurality of actuators are used in image forming apparatuses such as printers, copying machines, facsimile machines, and multifunction devices. For example, in the conveyance means for conveying the recording medium, the toner supply means for supplying the image forming material (toner), the drive source of the rotating body included in the image forming section, etc., the electromagnetic force of the coils of motors, clutches, solenoids, etc. Electromagnetic actuators powered by force are used.

A conventional image forming apparatus has been disclosed in which a drive control circuit that controls the drive of an electromagnetic actuator includes an electromagnetic actuator inspection device that inspects whether the electromagnetic actuator is operating correctly (for example, Patent Document 1).

In addition, in the electromagnetic actuator inspection device as disclosed in Patent Document 1, a Zener diode is installed in order to accelerate the attenuation of the regenerative current that occurs when the electromagnetic actuator stops operating, and to hasten the time when the electromagnetic actuator completely stops. May be used.

When a Zener diode fails in such an electromagnetic actuator inspection device, the failure state cannot be grasped in detail, and downtime is prolonged until the failure state is restored to a normal state. As a result, there has been a problem in that the downtime of an image forming apparatus equipped with an electromagnetic actuator inspection device is prolonged.

An object of the present invention is to provide an electromagnetic actuator drive circuit that allows failure states of circuit components to be grasped in more detail.

In order to solve the above technical problem, one aspect of the present invention forms an image by operating a movable part with an electromagnetic actuator, and also changes the state of a regenerative current attenuation element that attenuates the regenerative current generated when the electromagnetic actuator is driven. Regarding an image forming apparatus including an electromagnetic actuator drive unit that makes a determination based on a Zener voltage related to the regenerative current attenuation element, the electromagnetic actuator drive unit includes a drive unit that drives the electromagnetic actuator, and a PWM signal that outputs a PWM signal to the drive unit. a PWM drive control means for driving the electromagnetic actuator in a PWM manner, a Zener voltage detection means for detecting in a clamped state a Zener voltage related to a regenerative current attenuation element that attenuates a regenerative current generated when the electromagnetic actuator is driven; The Zener voltage detection means includes a state determination means for determining the state of the regenerative current attenuation element based on the voltage, and a notification means for notifying the determined state of the regenerative current attenuation element to the outside. The result of detecting the Zener voltage generated at the off timing in PWM driving of the actuator, and comparing the Zener voltage due to the regenerative current generated at the off timing in PWM driving of the electromagnetic actuator with a first threshold value by the state determining means. , when the Zener voltage is below the first threshold, the state of the regenerative current damping element is determined to be a short-circuit failure state , and the notification means notifies an external maintenance factor of the abnormality of the regenerative current damping element. or, as a result of the state determining means comparing the Zener voltage caused by the regenerative current generated at the off timing in PWM driving of the electromagnetic actuator with a first threshold value, the Zener voltage is determined to be equal to the first threshold value. If the Zener voltage is greater than the first threshold, the Zener voltage is compared with a second threshold that is greater than the first threshold, and if the Zener voltage is less than or equal to the second threshold, the state of the regenerative current attenuation element is determined to be normal . or when the state determining means compares the Zener voltage caused by the regenerative current generated at the off timing in PWM driving of the electromagnetic actuator with a first threshold value, when the Zener voltage is larger than the first threshold value. , and as a result, if the Zener voltage is larger than the second threshold, the state of the regenerative current attenuation element is determined to be an open failure state, and the notifying means drives the electromagnetic actuator. The image forming apparatus is characterized in that it issues an operation stop signal that stops the operation of the image forming apparatus including the image forming apparatus.

According to the present invention, it becomes possible to understand the failure state of a circuit component in more detail.

FIG. 1 is a circuit diagram showing an embodiment of an electromagnetic actuator drive circuit according to the present invention. FIG. 3 is a diagram showing an example of the operation of the circuit according to the embodiment. FIG. 6 is a diagram showing another example of the operation of the circuit according to the embodiment. FIG. 2 is a functional block diagram showing the functional configuration of an actuator control circuit according to the present embodiment. 1 is a flowchart showing an embodiment of an electromagnetic actuator driving method according to the present invention. 3 is a graph illustrating regenerative current generated in the actuator control circuit. 1 is a diagram showing a configuration example of an embodiment of an image forming apparatus according to the present invention. FIG. 2 is a diagram illustrating the hardware configuration of the image forming apparatus according to the embodiment.

Embodiments of an electromagnetic actuator drive circuit, an electromagnetic actuator drive method, and an image forming apparatus according to the present invention will be described below with reference to the drawings.

[Embodiment of image forming apparatus]
First, an embodiment of an image forming apparatus will be described. FIG. 7 is a diagram showing a configuration example of an MFP (Multi Function Peripheral) 1. As shown in FIG. The MFP 1 corresponds to an embodiment of an image forming apparatus that can be used as a printer, facsimile, scanner, or copying machine. The MFP 1 includes a document table 2, an image reading section 5, a sheet supply section 4, and an image forming section 6.

The sheet supply unit 4 supplies paper 110, which is a sheet-shaped recording medium, into the main body of the MFP 1. The sheet supply unit 4 includes a cassette 4a and a cassette 4b that respectively accommodate sheets 110 of different sizes. The conveyance path 4c has conveyance rollers for conveying the paper 110 contained in the cassette 4a and the cassette 4b to the image forming section 6. Note that the sheet supply section 4 may include a manual tray 4d on which the paper 110 is placed and a conveyance path that conveys the paper 110 placed on the manual tray 4d to the image forming section 6.

The conveyance path 4c includes a plurality of roller sections 47. The roller unit 47 is a pair of rollers or a group of rollers each composed of two or more rollers, and the rollers sandwich and grip the paper 110 and convey it. However, the present invention is not limited to this, and the paper 110 may be sandwiched between a plate member of the guide rail and one roller that contacts the plate member, and the paper 110 may be conveyed according to the rotational direction of the roller.

The registration roller unit 49 is a pair of rollers that controls the conveyance timing for forming an image at a proper position on the paper 110.

The document table 2 is a member that presses the document by sandwiching it between the glass plate of the image reading section 5, and rotates between an open position and a closed position with respect to the image reading section 5.

The image reading unit 5 reads a document and converts it into image data. The image reading section 5 includes a scanning optical system 5c, an imaging lens 5d, and an imaging section 5e. The scanning optical system 5c has a first carriage 5a on which a light source and a mirror member are mounted, and a second carriage 5b on which a mirror member is mounted. The document placed on the glass plate is irradiated with light by a light source mounted on the first carriage 5a, and reflects the irradiated light. The reflected light from the original is refracted by the mirror members mounted on the first and second carriages 5a and 5b, formed into an image by the imaging lens 5d, and read by the imaging section 5e.

The image forming section 6 forms an image on the surface of the paper 110 supplied from the sheet supply section 4 . The image forming section 6 includes an exposure device 6a, and a photoreceptor drum 6b and a developing device 6c for each color of cyan, magenta, yellow, and black. In addition, the image forming section 6 includes a transfer belt 6d and a fixing device 6e. In the case of copy processing, the exposure device 6a exposes the photoreceptor drum 6b based on the image read by the imaging section 5e, and forms a latent image of the read image on the photoreceptor drum 6b. The developing device 6c supplies toner to the photoreceptor drum 6b to perform development. The toner image developed on the photosensitive drum 6b is primarily transferred onto the transfer belt 6d. The transfer belt 6d rotates in the direction of the arrow and conveys the primarily transferred toner image to a point P. Thereafter, the transfer belt 6d secondarily transfers the toner image onto the paper 110 supplied from the sheet supply section 4 at a point P. The paper 110 on which the image has been transferred is conveyed to the fixing device 6e. The fixing device 6e heats the paper 110 and fixes the toner transferred onto the paper 110. The paper 110 on which the image has been formed in this manner is conveyed to the tray 7 and discharged to the outside of the MFP 1.

[Hardware configuration of MFP1]
Next, an overview of the hardware configuration of the MFP 1 will be described using FIG. 8. The MFP 1 includes a CPU 101, a ROM 102, a RAM 103, an HDD 104, a controller 105, a communication I/F 106, a detection IO unit 107, and a recording medium I/F 109, which are connected to each other by a bus.

The CPU 101 is an arithmetic unit that implements each function of the MFP 1 by reading programs and data from a storage device such as the HDD 104 and the ROM 102 onto the RAM 103 and executing processing.

The HDD 104 is a nonvolatile storage device that stores programs and data. The stored programs and data include programs that control the entire MFP 1 and data such as image forming conditions.

The controller 105 is connected to the image forming unit of the MFP 1, the transport unit that transports the paper 110, and the like, and controls these. The controller 105 notifies an actuator control circuit 10, which will be described later, of a signal that controls the operation timing of an electromagnetic actuator that drives a movable part such as a transport section. Further, the controller 105 controls the operation of the transport unit and the like in accordance with a signal issued from an actuator control circuit 10, which will be described later.

The communication I/F 106 is a peripheral device with a communication function that is connected via a network such as a LAN (Local Area Network) or a WAN (Wide Area Network) constructed using a data transmission path such as a wired and/or wireless line. This is an interface with MFP1.

The detection IO unit 107 is an interface with the detection sensor 108 and acquires a value output from the detection sensor 108. The detection sensor 108 is used as a conveyance means to detect the thickness of the paper 110 on which an image is formed, the conveyance timing, and the like. Further, as the detection sensor 108, for example, a configuration that detects a signal notified from the actuator control circuit 10, which will be described later, may be applied.

The recording medium I/F 109 is an interface with the paper 110. The MFP 1 can read and/or write on the paper 110 via the recording medium I/F 109. The paper 110 includes a flexible disk, a CD, a DVD (Digital Versatile Disk), an SD memory card (SD Memory Card), a USB memory (Universal Serial Bus memory), and the like.

[Embodiment of electromagnetic actuator drive circuit]
Next, an actuator control circuit 10, which is an embodiment of an electromagnetic actuator drive circuit according to the present invention, will be described using FIGS. 1 to 3. The actuator control circuit 10 includes an ASIC (Application Specific Integrated Circuit) 11, a transistor Q1 that serves as a switch that operates the actuator 12 in response to a drive signal from the ASIC 11, and circuit elements that constitute a control circuit that controls ON/OFF of the transistor Q1. It has . The actuator control circuit 10 corresponds to an electromagnetic actuator drive section mounted on the MFP 1.

The ASIC 11 outputs a drive signal from an output terminal (OUT) based on a control signal from a controller 105 included in the MFP 1. The drive signal output by the ASIC is, for example, a PWM signal.

The transistor Q1 turns on and off based on the PWM signal output from the ASIC 11. When the transistor Q1 is turned on, as shown in FIG. 2, an operating current flows through the actuator 12 from the +24V power supply. The actuator 12 is an electromagnetic actuator having a drive coil, and uses electromagnetic force generated when an operating current flows through the operating coil of the actuator 12 to drive various drive parts of the MFP 1. Therefore, transistor Q1 constitutes a driving means.

When the signal output from the ASIC 11 to the transistor Q1 becomes an OFF signal, no operating current flows to the actuator 12, so various driving parts stop. However, as illustrated in FIG. 3, immediately after the transistor Q1 turns from ON to OFF, a regenerative current is generated in the actuator 12, and while this regenerative current flows through the path illustrated in FIG. ), the operation of the actuator 12 does not completely stop. Therefore, it is desirable that the regenerative current disappears as quickly as possible. Therefore, the actuator control circuit 10 includes a Zener diode ZD1 so that the regenerative current generated in the actuator 12 is consumed. Zener diode ZD1 corresponds to a regenerative current attenuation element.

In the actuator control circuit 10, the ASIC 11 divides the contact voltage between the collector of the transistor Q1 and the actuator 12 by the third resistor R3 and the fourth resistor R4 while the regenerative current is occurring, and sets the voltage as the Zener voltage Vx. It is configured to detect at the IN terminal. The value of this Zener voltage Vx varies depending on the state of the Zener diode ZD1. In this embodiment, the state of the Zener diode ZD1 refers to whether the Zener diode ZD1 is in an "open fault state", "short fault state", or "normal".

Note that when the Zener diode ZD1 has an open failure, a back electromotive force, which is an overvoltage, is applied to the collector of the transistor Q1. If this back electromotive voltage is applied to the IN terminal, there is a possibility that the ASIC 11 will be destroyed. In order to prevent this, the IN terminal is configured to be clamped by a second diode D2.

[Functional blocks of ASIC11]
Next, functional blocks of the ASIC 11, which correspond to a control section that controls the operation of the actuator control circuit 10, will be explained. As shown in FIG. 4, the ASIC 11 includes a drive control section 111, a Zener voltage detection section 112, a voltage value comparison section 113, and a comparison result generation section 114.

The drive control unit 111 generates a PWM signal based on the control signal from the controller 105, and outputs it to the base terminal of the transistor Q1 via the output terminal (OUT). As already explained, the transistor Q1 is turned "ON" based on this PWM signal, a drive current flows through the drive coil of the actuator 12, and the actuator 12 operates. The drive control section 111 constitutes a PWM drive control means for PWM driving the transistor Q1, which is a drive means.

The Zener voltage detection section 112 detects the Zener voltage Vx generated after the timing when the transistor Q1 is turned off, based on the PWM signal generated by the drive control section 111. The Zener voltage detection section 112 notifies the voltage value comparison section 113 of a value obtained by digitally converting the detected Zener voltage Vx. The Zener voltage detection section 112 constitutes Zener voltage detection means.

The voltage value comparison unit 113 compares the value notified from the Zener voltage detection unit 112 with a preset threshold value, and notifies the comparison result generation unit 114 of the comparison result. The voltage value comparison section 113 constitutes a state determination means.

Based on the comparison result notified from the voltage value comparison unit 113, the comparison result generation unit 114 issues a control signal to the controller 105 according to the comparison result. The control signal issued from the comparison result issuing unit 114 is, for example, one for notifying maintenance personnel of the failure state of the Zener diode ZD1, which is one of the components included in the actuator control circuit 10. The comparison result issuing section 114 constitutes a notification means.

[Embodiment of electromagnetic actuator driving method]
Next, an embodiment of an electromagnetic actuator driving method according to the present invention will be described. FIG. 5 is a flowchart illustrating the flow of the electromagnetic actuator driving method. When the operation control signal for the actuator 12 is switched from ON to OFF (S501), the Zener voltage detection unit 112 detects the Zener voltage Vx due to the regenerative current generated thereafter (S502).

Next, the voltage value comparison unit 113 compares the Zener voltage Vx with a preset threshold value. An overview of this comparison process will be explained with reference to FIG. 6 as well. FIG. 6 illustrates the Zener voltage Vx generated by the regenerative current. As shown in FIG. 6, while the transistor Q1 is on, the Zener voltage Vx is at a low level.

Since a regenerative current is generated from the moment the transistor Q1 is turned off (Toff), the Zener voltage Vx also rises to a certain value. Since the regenerative current is generated until it is consumed by the Zener diode ZD1 (time T1) and then disappears, the value of the Zener voltage Vx also decreases accordingly.

Therefore, first, it is determined whether the value of the Zener voltage Vx during generation of regenerative current (time T1) is equal to or less than the first threshold Th1 (S503). If the Zener voltage Vx is less than or equal to the first threshold Th1, it is determined that the Zener diode ZD1 has a short-circuit failure. In the case of a short-circuit failure, the path of the regenerative current is not cut off, so no back electromotive force is generated, but the decay time of the regenerative current becomes longer. Therefore, the timing at which the actuator 12 completely stops is delayed.

That is, after the drive control unit 111 controls the actuator 12 to stop its operation, it takes a long time for the actuator 12 to completely stop its operation. During this time, the configuration whose operation is controlled by the actuator 12 continues to operate without stopping at the timing when it should normally stop. This increases the probability of a paper jam (jam) occurring due to the paper 110 stopping abnormally in the middle of the transport path in the MFP 1.

Therefore, if the Zener voltage Vx is equal to or less than the first threshold Th1 (S503/YES), the comparison result generating unit 114 issues a notification signal to the controller 105 to notify the maintenance personnel of the abnormality (S504).

If the Zener voltage Vx is not less than the first threshold Th1 (S503/NO), then it is determined whether the Zener voltage Vx is more than the second threshold Th2 (S505). Here, if the Zener voltage Vx is not equal to or higher than the second threshold Th2 (S505/NO), the Zener diode ZD1 is normal and the process ends.

If the Zener voltage Vx is equal to or higher than the second threshold Th2 (S505/NO), it is determined that the Zener diode ZD1 has an open failure. In the case of an open failure, the path through which the regenerative current flows is cut off, so a back electromotive voltage is generated and the value of the Zener voltage Vx becomes high. An overvoltage due to this back electromotive force is applied to the transistor Q1. If an overvoltage is applied, there is a risk that the transistor Q1 will be destroyed, so as an immediate processing, an operation stop signal is issued to stop the entire MFP 1 (S506).

The first threshold Th1 explained above is, for example, 2 [V]. Further, the second threshold Th2 is, for example, 3 [V]. Therefore, if the value of the Zener voltage Vx is 2 [V] or less, a notification signal is issued, and if the value of the Zener voltage Vx is 3 [more than], an operation stop signal is issued to stop the operation of the MFP 1. If the value of the Zener voltage Vx is higher than 2 [V] and less than 3 [V], no special processing is performed.

Note that the first threshold Th1 and the second threshold Th2 are not limited to the values exemplified above, and are used to determine whether the Zener diode ZD1 is normal, has a short-circuit failure, or has an open failure. It is sufficient if it can be used for.

As described above, according to the electromagnetic actuator driving method executed in the actuator control circuit 10 according to the present embodiment, a predetermined voltage (Zener voltage Vx) during a period in which regenerative current is generated is detected, and the predetermined voltage (Zener voltage Vx) is detected. is determined using multiple threshold values to identify the failure mode. That is, in the circuit configuration using the Zener diode ZD1, a plurality of threshold values are provided for the output voltage of the driver during the regenerative current period to determine the failure mode, and the response to the machine (MFP1) is changed depending on the failure mode.

Therefore, the actuator control circuit 10 according to the present embodiment changes the signal specifying the response to the MFP 1 depending on the failure mode of the Zener diode ZD1. Depending on the failure mode, it may be possible to continue using the MFP 1 with normal functions, so in that case, simply notifying the error causes the MFP 1 to continue operating, reducing machine downtime.

Note that the present invention is not limited to the above-described embodiments, and can be modified in various ways without departing from the technical gist thereof. All of these matters are covered by the present invention. Although the embodiments described above are preferred examples, those skilled in the art can realize various modifications based on the disclosed contents. Such modifications are also included within the technical scope of the claims.

1: MFP
10: Actuator control circuit 11: ASIC
12: Actuator 47: Roller section 49: Registration roller section 101: CPU
102:ROM
103: RAM
104: HDD
105: Controller 106: Communication I/F
107: Detection IO unit 108: Detection sensor 109: Recording medium I/F
110: Paper 111: Drive control section 112: Zener voltage detection section 113: Voltage value comparison section 114: Comparison result generation section ZD1: Zener diode

Japanese Patent Application Publication No. 2012-014009

Claims (3)

An electromagnetic actuator that operates a movable part with an electromagnetic actuator to form an image, and that determines the state of a regenerative current attenuating element that attenuates a regenerative current generated when the electromagnetic actuator is driven, based on a Zener voltage related to the regenerative current attenuating element. An image forming apparatus including a drive section,
The electromagnetic actuator drive section is
a driving means for driving an electromagnetic actuator;
PWM drive control means for outputting a PWM signal to the drive means to drive the electromagnetic actuator in PWM;
Zener voltage detection means for detecting, in a clamped state, a Zener voltage related to a regenerative current attenuating element that attenuates a regenerative current generated when the electromagnetic actuator is driven;
a state determining means for determining the state of the regenerative current attenuation element based on the Zener voltage;
Notifying means for notifying the determined state of the regenerative current attenuation element to the outside,
The Zener voltage detection means detects the Zener voltage generated at an off timing in PWM driving of the electromagnetic actuator,
The state determining means compares the Zener voltage caused by the regenerative current generated at the off timing in PWM driving of the electromagnetic actuator with a first threshold value, and if the Zener voltage is equal to or less than the first threshold value, the regenerative current attenuation is performed. Determining the state of the element as a short-circuit failure state , the notification means issues a notification signal to notify an external maintenance factor of an abnormality in the regenerative current attenuation element,
Or
The state determining means compares the Zener voltage caused by the regenerative current generated at the off timing in PWM driving of the electromagnetic actuator with a first threshold value, and if the Zener voltage is larger than the first threshold value, the Zener voltage is Compare the first threshold with a second threshold, and as a result, if the Zener voltage is less than or equal to the second threshold, determine the state of the regenerative current attenuation element to be normal ;
Or
The state determining means compares the Zener voltage due to the regenerative current generated at the off timing in PWM driving of the electromagnetic actuator with a first threshold value, and if the Zener voltage is larger than the first threshold value, the Zener voltage is determined to be higher than the second threshold value. As a result, when the Zener voltage is larger than the second threshold, the state of the regenerative current attenuation element is determined to be an open failure state, and the notifying means performs image forming including the electromagnetic actuator drive section. issuing an operation stop signal that stops the operation of the device;
An image forming apparatus characterized by: The driving means is a transistor connected to the electromagnetic actuator,
The PWM drive control means outputs the PWM signal to the base of the transistor to turn on/off the transistor to drive the electromagnetic actuator in a PWM manner,
The image forming apparatus according to claim 1, wherein the Zener voltage detection means detects a voltage obtained by dividing a contact voltage between the transistor and the electromagnetic actuator. An electromagnetic actuator that operates a movable part with an electromagnetic actuator to form an image, and that determines the state of a regenerative current attenuating element that attenuates a regenerative current generated when the electromagnetic actuator is driven, based on a Zener voltage related to the regenerative current attenuating element. An electromagnetic actuator driving method performed in an image forming apparatus including a driving section, the method comprising:
When the electromagnetic actuator drive unit drives the electromagnetic actuator, it outputs a PWM signal to drive the electromagnetic actuator in a PWM manner,
Detecting the Zener voltage due to the regenerative current generated at the off timing during PWM driving of the electromagnetic actuator in a clamped state,
comparing the detected Zener voltage with a first threshold;
When the Zener voltage is below the first threshold, determining the state of the regenerative current attenuation element to be a short-circuit failure state,
Emit a notification signal to notify an abnormality of the regenerative current attenuation element in response to an external maintenance factor,
Or
comparing the detected Zener voltage with the first threshold;
When the Zener voltage is greater than the first threshold, comparing the Zener voltage with a second threshold that is greater than the first threshold;
When the Zener voltage is less than or equal to the second threshold , the state of the regenerative current attenuation element is determined to be normal ;
Or
comparing the detected Zener voltage with a first threshold;
when the Zener voltage is greater than the first threshold, comparing the Zener voltage with the second threshold;
When the Zener voltage is larger than the second threshold , the state of the regenerative current attenuation element is determined to be an open failure state,
issuing an operation stop signal that stops the operation of the image forming apparatus including the electromagnetic actuator drive section;
An electromagnetic actuator driving method characterized by: