JP2022122095A - Image forming apparatus - Google Patents

Abstract

To stop power supply to a substrate when a cover covering the substrate in a state in which a plug-in off mode is set in the maintenance of an image forming apparatus.SOLUTION: In an image forming apparatus 10 according to the present invention, a control unit 45 sets a plug-in off mode for causing a second switch circuit 42 to cut off operation power supplied from a power supply unit 33 to a device 44 to bring the device 44 into a non-operating state, and if an open state of a cover covering a substrate 31 is detected by an illuminance sensor 36 while the plug-in off mode is set, causes the second switch circuit 42 to cut off the supply of operation power from the power supply unit 33 to the substrate 31.SELECTED DRAWING: Figure 4

Description

The present invention relates to an image forming apparatus capable of attaching and detaching a substrate for maintenance, and more particularly to a technique for controlling power supply to the substrate.

In an image forming apparatus, various devices constituting the image forming apparatus, a plurality of boards for controlling these devices, and power supplied from a commercial power supply are supplied to each device and each board to supply operating power. It is equipped with a power supply unit, etc. During maintenance of such an image forming apparatus, it is necessary to cut off the power supply from the commercial power source and bring each device and each substrate into a stopped state. If maintenance is performed without interrupting the power supply from the commercial power source, various troubles will occur.

The image forming apparatus described in Patent Document 1 includes a cover that covers devices such as a charging section, a movable section driven by a motor, and a laser that emits laser light. A safety switch is provided to automatically cut off the cover, and the opening and closing of the cover can be detected by the safety switch.

JP 2004-148724 A

In recent years, some image forming apparatuses have omitted an AC switch that can be manually turned on and off in order to reduce costs. For maintenance of such an image forming apparatus, instead of turning off the AC switch, it is necessary to pull out the plug of the cord of the image forming apparatus connected to the outlet of the commercial power supply. Further, in the image forming apparatus, a plug-in off mode is appropriately set in which the supply of operating power to the device is turned off to reduce power consumption. However, regardless of whether or not the plug-in off mode is set, operating power is supplied to the board on which the control unit and the like are mounted.

However, when performing maintenance on the image forming apparatus, if the plug-in off mode is set, the device is not operating. It can happen that you forget to pull the plug. In this case, for maintenance, for example, when a cable connected to the GND shield of the board is removed, this cable floats in the air and touches a current-carrying point of another board that continues to receive the supply of operating power. A ground fault may occur at this energized portion, which may cause failure of the circuit board or the like.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances. The purpose is to stop the supply.

An image forming apparatus according to one aspect of the present invention includes a device constituting the image forming apparatus, a substrate on which an electronic circuit is mounted, a cover that is supported so as to be openable and closable and covers the substrate when closed, and the cover. a detection unit that detects that the is opened; a power supply unit that receives power from a commercial power supply and supplies operating power to the device and the substrate; and a power supply that is supplied from the power supply unit to the device and the substrate and a plug-in off mode that shuts off the operating power supplied from the power supply unit to the device by the cutoff unit, and puts the device in a non-operating state. and when the detection unit detects that the cover is opened while the plug-in off mode is set, the cutoff unit cuts off the supply of operating power from the power supply unit to the board. and a part.

According to the present invention, during maintenance of the image forming apparatus, if the plug-in off mode is set, power supply to the substrate can be stopped when the cover covering the substrate is opened.

1 is a sectional view showing an image forming apparatus according to an embodiment of the invention; FIG. (A) and (B) are a front view and a side view showing the layout positions of substrates and the like in the image forming apparatus of the present embodiment. 2 is a block diagram showing a power supply unit, a control board, each board, each device, etc. in the image forming apparatus of the present embodiment; FIG. It is a figure which shows the circuit of the output side of an illuminance sensor. It is a figure which shows the 1st and 2nd switch circuit in a power supply part. 4 is a flow chart showing power supply control to each substrate and each device in the image forming apparatus of the present embodiment.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a cross-sectional view of an image forming apparatus according to an embodiment of the present invention viewed from the front. This image forming apparatus 10 includes an image reading section 11 , an image forming section 12 and a post-processing section 18 .

The image reading unit 11 has an image pickup device for optically reading an image of a document, and converts an analog output of the image pickup device into a digital signal to generate image data representing the image of the document.

The image forming section 12 forms an image of the document on recording paper, and includes an image forming unit 3M for magenta, an image forming unit 3C for cyan, an image forming unit 3Y for yellow, and an image forming unit 3Y for black. It has a unit 3Bk. In each of the image forming units 3M, 3C, 3Y, and 3Bk, the surface of the photoreceptor drum 4 is uniformly charged, the surface of the photoreceptor drum 4 is exposed, and an electrostatic latent image is formed on the surface of the photoreceptor drum 4. is formed, the electrostatic latent image on the surface of the photoreceptor drum 4 is developed into a toner image, and the toner image on the surface of the photoreceptor drum 4 is primarily transferred to the intermediate transfer belt 5 . Thereby, a color toner image is formed on the intermediate transfer belt 5 . This color toner image is secondarily transferred onto the recording paper P transported through the transport path 8 from the paper feeding unit 14 in the nip area N between the intermediate transfer belt 5 and the secondary transfer roller 6 .

Thereafter, the recording paper P is heated and pressurized by the fixing device 15, the toner image on the recording paper P is fixed by thermocompression, and the recording paper P is conveyed to the post-processing section 18 through the discharge roller 16. .

The post-processing section 18 subjects the recording paper P or the bundle thereof to stapling processing, center folding processing, or the like, and discharges the printed matter composed of the recording paper P or the bundle thereof to the discharge tray 19 .

2A and 2B are a front view and a side view showing the arrangement positions of the substrates 31, the control substrate 32, the power source section 33, etc. in the image forming apparatus 10. FIG. As shown in FIGS. 2A and 2B, a plurality of substrates 31, a control substrate 32, a power source section 33, an opening/closing cover 34, and the like are arranged on the rear side of the main housing 21 of the image forming apparatus 10. there is

Here, the image forming apparatus 10 includes the image reading section 11, the image forming section 12, and the post-processing section 18 as described above. The image reading unit 11 is provided with a device such as an imaging element. The image forming unit 12 includes a charging unit that charges the surface of the photoreceptor drum 4, a scanner that exposes the surface of the photoreceptor drum 4, a developing unit that develops an electrostatic latent image on the surface of the photoreceptor drum 4 into a toner image, A device such as a transfer section that primarily transfers the toner image on the surface of the photosensitive drum 4 to the intermediate transfer belt 5 is provided. The post-processing section 18 is provided with devices for stapling, punching, and the like. In addition, the image forming apparatus 10 is provided with many devices.

Each substrate 31 is, for example, a substrate on which a control circuit or the like for controlling those devices is mounted. The power supply unit 33 receives power supply from a commercial power supply, and supplies operating power to each device and each substrate 31. An opening/closing cover 34 is arranged to cover each substrate 31, and the opening/closing cover 34 It is supported by a hinge (not shown) at one end so that it can be opened and closed, and the opening 35 provided in the back plate of the main housing 21 is opened or closed as the opening and closing cover 34 is opened and closed.

When the opening/closing cover 34 is opened to open the opening 35 , each board 31 is exposed through the opening 35 , and the operator can perform maintenance of each board 31 .

An illuminance sensor 36 is provided on the control board 32 . When the opening/closing cover 34 is opened and the opening 35 is opened, outside light enters the illuminance sensor 36 and is detected by the illuminance sensor 36 . Therefore, when the illuminance sensor 36 detects the outside light, the opening/closing cover 34 is opened and the opening 35 is opened.

FIG. 3 is a block diagram showing the configuration of the power supply unit 33 and the like. As shown in FIG. 3, the power supply unit 33 includes an AC-DC conversion unit 40 that receives an AC voltage Vac from a commercial power supply AC and outputs a DC voltage Vdc, and between the AC-DC conversion unit 40 and each substrate 31: A first switch circuit 41 that is inserted to turn on and off the supply of the DC voltage Vdc to each substrate 31, and is inserted between the AC-DC conversion section 40 and each device 44 as described above to switch to each device 44. and a second switch circuit 42 for turning on and off the supply of the DC voltage Vdc.

AC-DC converter 40 receives AC voltage Vac of commercial power source AC through cord 40A on the primary side, converts AC voltage Vac to DC voltage Vdc, and outputs DC voltage Vdc from the secondary side.

The illuminance sensor 36 is mounted on the control board 32 . The control board 32 is provided with an illuminance sensor 36 and a control section 45 for switching on and off the first switch circuit 41 and the second switch circuit 42 of the power supply section 33 based on the output of the illuminance sensor 36 . The DC voltage Vdc of the AC-DC converter 40 is constantly input to the control board 32, and the operating states of the illuminance sensor 36 and the controller 45 are continuously maintained.

For example, as shown in FIG. 4, a DC voltage Vdc is applied to the illuminance sensor 36, and the detection output of the illuminance sensor 36 is output to the control section 45 through the switching element S1 of the output circuit 51. FIG.

Moreover, as shown in FIG. 5, the first switch circuit 41 and the second switch circuit 42 are provided with a cutoff circuit 52 and an output circuit 53 . The control unit 45 turns on and off the switching element S2 of the cutoff circuit 52 according to the detection output of the illuminance sensor 36 to turn on and off the DC voltage Vdc output from the output circuit 53 . Therefore, the control unit 45 turns on and off the first switch circuit 41 (or the second switch circuit 42) to supply the respective substrates 31 (or the respective devices 44) through the first switch circuit 41 (or the second switch circuit 42). The applied DC voltage Vdc is turned on and off.

In the image forming apparatus 10 having such a configuration, the first switch circuit 41 and the second switch circuit 42 are normally turned on. Therefore, the DC voltage Vdc of the AC-DC conversion unit 40 is supplied to each substrate 31 through the first switch circuit 41 to operate each substrate 31, and the DC voltage Vdc of the AC-DC conversion unit 40 is supplied to the second circuit. It is supplied to each device 44 through the switch circuit 42 to operate each device 44 .

Further, the control unit 45 of the control board 32 determines the occurrence of an error based on the detection outputs of a plurality of sensors (not shown), or measures the duration of the stopped state of the image forming apparatus 10, and When it is determined that the duration has reached the predetermined time, the second switch circuit 42 is turned off to cut off the supply of the DC voltage Vdc to each device 44 and stop the operation of each device 44 . However, the first switch circuit 41 remains on, and the operation of each circuit mounted on each substrate 31 is maintained.

A state in which each device 44 is stopped by turning off the second switch circuit 42 is called a plug-in off mode. When an operation unit (not shown) is operated by the user to input an instruction to drive each device 44, the control unit 45 turns on the second switch circuit 42 in response to the instruction to drive each device. The supply of the DC voltage Vdc to 44 is restarted to operate each device 44 . This cancels the plug-in off mode.

The image forming apparatus 10 does not have an AC switch for manually turning on/off the image forming apparatus 10 for cost reduction. Therefore, when performing maintenance on the image forming apparatus 10, instead of turning off the AC switch, it is necessary to pull out the plug of the cord 40A of the image forming apparatus 10 connected to the outlet of the commercial power supply 47. FIG.

However, when performing maintenance on the image forming apparatus 10, if the plug-in off mode is set, each device 44 is not operating, so the operator may misunderstand that the image forming apparatus 10 is in a stopped state. Therefore, the user may forget to pull out the plug of the image forming apparatus 10 . In this state, when the opening/closing cover 34 is opened and one of the substrates 31 is pulled out, for example, the cable connected to the GND shield of the substrate 31 floats in the air and the other substrates that continue to receive operating power are suspended. 31, and a ground fault occurs at this current-carrying point, causing a failure of those substrates 31 or the like.

In this embodiment, when the plug-in off mode is set, the opening/closing cover 34 is opened to release the opening 35, and when the illuminance sensor 36 detects outside light (for example, the amount of received light (when the output from the illuminance sensor 36 corresponding to ) reaches a predetermined value or more, the control unit 45 of the control board 32 determines that the opening/closing cover 34 is open based on the detection output of the illuminance sensor 36 . Then, when the control section 45 determines that the opening/closing cover 34 is opened, the control section 45 turns off the first switch circuit 41 . As a result, the supply of the DC voltage Vdc from the AC-DC converter 40 to each board 31 is cut off, and the operation of each circuit mounted on each board 31 is stopped. As a result, it is possible to prevent occurrence of the ground fault as described above.

When the plug-in off mode is not set, the control unit 45 of the control board 32 determines that the opening/closing cover 34 is open, and if each device 44 is in operation, , the second switch circuit 42 is turned off to put each device 44 in a non-operating state, and the first switch circuit 41 is turned off.

Next, the control procedure by the control unit 45 of the control board 32 as described above will be described in order with reference to the flowchart shown in FIG.

First, the control unit 45 of the control board 32 waits for a detection output indicating that the opening/closing cover 34 has been opened from the illuminance sensor 36 (S101 "No").

When the operator opens the open/close cover 34 while the image forming apparatus 10 is set to the plug-in off mode, the illuminance sensor 36 sends a detection output indicating that the open/close cover 34 has been opened. The control unit 45 determines that the opening/closing cover 34 is opened based on the detection output of the illuminance sensor 36 (S101 "Yes").

For example, the control unit 45 determines the occurrence of an error based on the detection outputs of a plurality of sensors before the opening/closing cover 34 is opened, or determines whether the duration of the stopped state of the image forming apparatus 10 reaches a predetermined time in advance. If so, it is assumed that the second switch circuit 42 is turned off to stop the operation of each device 44 and the plug-in off mode has already been set. In this case, the control unit 45 keeps the second switch circuit 42 off to continue stopping the operation of each device 44 (S103).

Then, the control unit 45 turns off the first switch circuit 41 to cut off the supply of the DC voltage Vdc from the AC-DC conversion unit 40 to each substrate 31, thereby stopping the operation of each substrate 31 (S104). As a result, occurrence of a ground fault in the substrate 31 can be prevented.

Note that even if the plug-in off mode is not set when the control unit 45 determines that the opening/closing cover 34 is open based on the detection output of the illuminance sensor 36, the second switch circuit 42 is turned on. cut off the supply of the DC voltage Vdc to each device 44 to stop the operation of each device 44, turn off the first switch circuit 41, and stop the operation of each circuit mounted on each substrate 31 Let This keeps the safety of workers or users.

As described above, in this embodiment, when the opening/closing cover 34 is opened, if the plug-in off mode is set and each device 44 is in a non-operating state, the AC-DC converter 40 will , and the operation of each substrate 31 is stopped, it is possible to prevent the above-described ground fault from occurring. Moreover, if each device 44 is in an operating state when the opening/closing cover 34 is opened, each device 44 is put in a non-operating state, so that the safety of the operator or user is maintained.

In addition, since the illumination sensor 36 is mounted on the control board 32, it is sufficient to provide a wiring for guiding the detection output of the illumination sensor 36 on the control board 32, and it is not necessary to run the wiring long.

In the above embodiment, when the plug-in off mode is set and the opening/closing cover 34 is opened, if each device 44 is in an operating state, each device 44 is put into a non-operating state. Furthermore, the first switch circuit 41 is turned off to stop the operation of each substrate 31, but when a certain period of time (for example, 24 hours) has passed since the plug-in off mode was set, the controller 45 Even if the detection output of the illuminance sensor 36 indicates that the opening/closing cover 34 is closed, the first switch circuit 41 may be switched off to cut off the supply of operating power to each board 31 . This makes it possible to more effectively prevent various troubles during maintenance.

In the above embodiment, the illuminance sensor 36 is mounted on the control board 32. However, the illuminance sensor 36 can be placed anywhere as long as it receives external light when the opening/closing cover 34 is opened. may Further, instead of the illuminance sensor 36, another switch such as a limit switch that can detect that the open/close cover 34 is open is provided, and the control unit 45 opens and closes based on the on/off of the other switch. You may make it detect that the cover 34 is opened.

Also, the configuration and processing of the above embodiment described with reference to FIGS. 1 to 6 are merely examples of the present invention, and are not intended to limit the present invention to the configuration and processing.

10 Image forming apparatus 11 Image reading unit 12 Image forming unit 21 Main housing 31 Board 32 Control board 33 Power supply unit 34 Open/close cover 36 Illuminance sensor 45 Control unit

Claims (4)

a device constituting an image forming apparatus;
A substrate on which electronic circuits are mounted,
a cover that is openably and closably supported by the apparatus main body and covers the substrate when closed;
a detection unit that detects that the cover is opened;
a power supply that receives power from a commercial power source and supplies operating power to the device and the substrate;
a cutoff unit that cuts off operating power supplied from the power supply unit to the device and the substrate;
When a plug-in off mode is set in which the cut-off unit cuts off the operating power supplied from the power supply unit to the device and the device is put into a non-operating state, and the plug-in off mode is set. and a control unit that causes the cutoff unit to cut off supply of operating power from the power supply unit to the substrate when the detection unit detects that the cover has been opened. When the plug-in off mode is set and a certain period of time has passed since the plug-in off mode was set, the control unit controls the operation from the power supply unit to the board even if the detection output from the detection unit indicates that the cover is closed. 2. The image forming apparatus according to claim 1, wherein power supply is interrupted. The detection unit is an illuminance sensor that is provided on the substrate and detects light incident on the substrate when the cover is opened,
3. The image forming apparatus according to claim 1, wherein the controller determines that the cover has been opened based on a detection output of the illuminance sensor. the detection unit is an open/close switch that is turned off when the cover is open and turned on when the cover is closed;
3. The image forming apparatus according to claim 1, wherein the controller determines that the cover has been opened in response to turning off of the open/close switch.

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