JP2003217417A - Power feeding device having interlock circuit and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an interlock power source circuit easy to recognize an operation abnormal tendency of an electric relay and an image forming device using the circuit and to monitor the operation abnormal tendency. <P>SOLUTION: Each load is connected to an interlock switch 73 to be turned OFF/ON by interlocking with the opening/closing of a cover, a plurality of electric relays 86 and 8 to be operated by a power source line +24 V inserted with the switch 73 and a rear stage of a contact of the switch 73 and the relays 86 and 8 so that an output of the relay 86 at a front stage on the circuit may be a trigger of the relay 8 at the rear stage. When the switch 73 is turned OFF/ON by the cover opening/closing operation, the plurality of relays 86 and 8 are sequentially turned OFF/ON. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply device having an interlock circuit and an image forming apparatus using the power supply device. Specifically, although not intended to be limited to this,
The present invention relates to an interlock circuit provided to protect an operator of office equipment and the like, and particularly to detection of a contact abnormality of an electric relay used in the interlock circuit.

[0002]

2. Description of the Related Art Conventionally, in office equipment, an interlock circuit has been used. For example, a DC power supply voltage of a load drive circuit device such as a motor is used by using a switch linked to opening and closing a front door of the equipment. By opening and closing, the operator is prevented from operating in a dangerous operating state. As a result, even if the power of the device is turned on, if the front door is open, the drive voltage of the load is not applied, that is, the load does not move, and Accidents that occur can be prevented.

Generally, in order to realize this structure,
As an interlock circuit, a power supply voltage line to be opened / closed is distributed to the door, and the distributed power supply voltage line is serially connected to a switch that opens / closes the circuit by an opening / closing mechanism of the door.

However, in this method, if the load to be interrupted as the interlock circuit requires a large current, it is necessary to distribute the large current to the door, which is not very desirable from the viewpoint of suppressing electromagnetic radiation noise. Absent. Also, when there are multiple doors as an interlock mechanism, and when there are multiple circuits to be shut off,
They require switches for the combination. For example, there are front doors, left doors, and right doors, which can open the circuit regardless of which one is open.
If there are 24V systems 2 and 3 systems, 3 × 3 = 9 switches are required.

Therefore, as a method other than the above, an electric relay (which may be simply referred to as a relay hereinafter) is used to interrupt the power supply voltage line of the load system, and the drive circuit of the relay is changed to an interlock switch (door switch). ) There is also a method to cut off. In this case, in the example of the above-mentioned three cut-off points and three power sources, the 24V system 1 can be opened and closed by a door switch, and a relay drive circuit is also assigned. Then, as a relay to be driven, one having two circuits is used, and the a-contact side is assigned as a 5V system and the b-contact side is assigned as a 24V system 2. With this configuration, the door can be opened with a small number of parts, that is, three switches for opening and closing the 24V system 1 (relay drive circuit) and one relay for opening and closing the 24V system and the 5V system. Even so, it is possible to realize an interlock circuit that can shut off all three power sources.
In this case, three door switches are connected in series to connect between the 24V system 1 and the relay coil. Of course, the power source for driving the relay does not have to be limited to the interlock voltage (24V system, 24V system, 2V system).

However, in general, in circuit switching parts such as switches and relays, when closing contacts, an inrush current flows into a capacitive load or a stray capacitance provided on the load side, and an arc or the like is generated by the inrush current. There is a problem that the contacts are welded. If the contacts are opened / closed while the load is energized, the load will be turned on / off directly by the circuit opening / closing parts. At that time, if an arc or the like occurs between the contacts and the energization current value is large. However, there is a problem that the contacts are welded.

In particular, in the case of relays, in general, compared with a switch having the same current capacity, many of them have lower resistance to arc and the like. Therefore, care must be taken not to turn on / off when energized, and consideration of further suppression of inrush current, etc. Has been done in various ways. As a technique for dealing with the relay, Japanese Patent Laid-Open No. 2000
For example, the technique described in JP-A-215772 can be used.

[0008]

From the viewpoint of protecting the contacts of the circuit opening / closing component of the interlock, a method of preventing the inrush current itself, a method of suppressing the inrush current, etc.
Various studies are underway.

[0009] For example, as a method of preventing the former inrush current itself, there is a technique described in Japanese Patent Laid-Open No. 2000-215772 as a countermeasure example of an interlock relay, and a latter method of suppressing current is as follows. Many publicly known technologies such as adding a limiting circuit have been announced, and one method is to satisfy the function while suppressing the load capacity.

However, in these conventional methods, for example, in the technique described in Japanese Patent Application Laid-Open No. 2000-215772,
Since it is a mechanism that does not generate an inrush current itself, it is perfectly satisfactory from the viewpoint of relay contact protection, but since the rise time of the circuit is delayed, there must be no side effects as a system. In addition, it is necessary to pay attention to oscillation etc. as the circuit operation, and it is impossible to make it by a simple design.

Further, in the method of adding a current limiting circuit or suppressing the load capacitance, even if the inrush current can be suppressed, there is a trade-off with the function, which greatly affects the selection of the load. In addition, there is often a trade-off between the achievement of functions and the service life of relay components, and it may be acceptable if the service life specifications of the equipment in which this circuit is mounted or the required life of safety standards are satisfied. If the relay life is equal to the equipment life specification, the equipment specification is satisfied, but the safety is not guaranteed for users used with specifications longer than that. turn into.

Actually, the number of times the SW is turned ON / OFF is targeted for general usage, and when the condition of the device is not so good, the ON / OFF of the main SW is frequently performed, and copying is performed. For machines / printers, if the paper is bad, jams will occur frequently and doors will be opened and closed frequently. In this case, the SW and relay life specifications may be exceeded. In addition, there are many devices in the market that are used for longer than their useful lives, and even if the devices are operating without trouble, they often exceed the life specifications.

However, since the interlock circuit is a circuit for operator protection in the first place, it goes without saying that there is no abnormality, but even if there is an abnormality, a dangerous operating state occurs for the operator. It can be said that it is desirable not to do so.

A first object of the present invention is to provide a power supply circuit in which it is easy to grasp the tendency of operation abnormality of an electric relay and an image forming apparatus using the power supply circuit. The second purpose is to monitor the tendency of operation abnormality. To aim.

[0015]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems of the prior art. First, a plurality of relays each having an exciting coil are used as circuit switching parts of an interlock circuit. , The load system for interlock operation is assigned to each. The circuit configuration is 1
If the drive coil of another relay is connected to the output of the first relay and there are more than one relay, do the same with 2
Connect the drive coil of the other relay to the output of the first relay.

And in a preferred embodiment of the present invention,
A contact open / close detection circuit is connected to each of the distributed load lines, and the detection output is monitored by a digital device such as a CPU, MPU, or discrete logic circuit. As for this circuit operation, multiple load power supplies that have been distributed are sequentially turned on / off.
Therefore, the device to which the contact open / close detection circuit is connected can also detect the abnormality of the contact by monitoring the sequence.

The relay contacts do not suddenly weld, but the magnitude of the inrush current value and the dI / dt of the inrush current.
Due to the (differential value) and the magnitude of the steady energization current value, the contact transfer gradually occurs. That is, the shape of the contact itself changes in the direction in which the gap between the contacts shrinks, and the contact eventually melts and does not turn off. However, while the contact transfer occurs, the relay coil is energized. However, the contact is quite ON (ON;
There is an abnormal tendency that the contacts do not close (OFF) but the contacts do not turn OFF (OFF; open) even though the relay coil is turned off.

In a preferred embodiment of the present invention, such a state, that is, an abnormal state before the final fracture state such as welding is detected.

Specifically, it is as follows: (1) Interlock switch (73), first electrical relay (86) which is switched from off to on by switching the interlock switch from off to on. ,and,
A second electric relay (8) that is switched from off to on by switching the relay contact of the first electric relay from open to closed is provided, and the first load (via the relay contact of the first electric relay (86) ( 5A) and a power supply device having an interlock circuit, which supplies power to the second load (5B) via the relay contacts of the second electric relay (8).

In order to facilitate understanding, the symbols of the corresponding elements or corresponding elements of the embodiments shown in the drawings and described later are added for reference. The same applies to the following.

According to this, the first load (5A) and the second load (5B) distributed to the system of the first electric relay (86) and the system of the second electric relay (8) are the interlock switch. ON / OFF is turned ON / OFF sequentially, so the interlock switch is turned ON.
There is a time difference between each time delay from the ON / OFF switching to the ON / OFF switching of the first load (5A) and the second load (5B), which makes it easy to detect the time delay and It is possible to grasp the abnormality tendency of the contact and detect the abnormality by measuring the value of the above and by monitoring the ON / OFF switching sequence.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION (2) From the switching of the interlock switch (73) from on to off, a set time (T
1, T2) further includes an opening monitoring means (MPU / F, Co, L1, L2, c1, c2) for monitoring whether the relay contact of the electric relay (86, 8) is switched from OFF to ON. The power supply device according to (1) above.

For example, letting the opening delay abnormality determination threshold value of the first electric relay (86) from ON to OFF be T1, and the opening delay abnormality determination threshold value of the second electric relay (8) from ON to OFF, T2. The opening monitoring means detects the first from the time when the interlock switch (73) is switched from ON to OFF.
The elapsed time t1 from the time when the electric relay (86) is switched from ON to OFF and the elapsed time t2 from the time when the second electric relay (8) is switched from ON to OFF are measured, and t1> When it is T1, it is determined that the first electric relay (86) is in the opening delay tendency, and when t2> T2, it is determined that the second electric relay (8) is in the opening delay tendency. It can be seen that there is a tendency before the electrical relay does not switch from on to off.

(3) The interlock switch (7
3) After switching from off to on, the set time (T1B,
The power feeding device according to (1) or (2), further including a closing monitoring unit (MPU) for monitoring whether the relay contact of the electric relay (86, 8) is switched from OFF to ON in T2B). .

For example, the closing delay abnormality determination threshold value of the first electric relay (86) from OFF to ON is T1B, and the closing delay abnormality determination threshold value of the second electric relay (86) from OFF to ON is T2B. Then, with the opening monitoring means, from the time when the interlock switch (73) is switched from OFF to ON,
The elapsed time t1 from the time when the first electric relay (86) is switched from off to on and the elapsed time t2 from the time when the second electric relay (8) is switched from off to on are measured, When t1> T1B, it is determined that the first electric relay (86) has a closing delay tendency, and when t2> T2B, it is determined that the second electric relay (8) has a closing delay tendency.
It can be seen that there is a tendency before the electrical relay does not switch from off to on.

(4) The interlock switch (7
A power feeding device having the interlock circuit according to any one of (1) to (3), which feeds power to the third load (5) via 3). According to this, the first in the load group /
The load that is preferably turned off is set to the third load (5), the next-order load is set to the first load (5A), and the next-order load is set to the second load (5B). A load on / off sequence can be defined.

(5) An electrostatic latent image is formed on the photoreceptor (101), the electrostatic latent image is visualized as a toner image by the developing device (106), and the toner image is directly or intermediately transferred to an intermediate medium. In an image forming apparatus that indirectly transfers to a transfer paper via an interlock switch (73) that opens and closes by opening a door or a front cover of the image forming apparatus; switching the interlock switch from off to on A first electric relay (86) which is switched from off to on by the power supply to the first load (5A) of the image forming apparatus; and from off by switching the relay contact of the first electric relay from open to closed. An image forming apparatus comprising: a second electric relay (8) which is switched on and supplies power to a second load (5B) of the image forming apparatus.

According to this, in the image forming apparatus such as a printer, the first load (5A) distributed to the system of the first electric relay (86) and the system of the second electric relay (8).
And the second load (5B) turns on the interlock switch
The ON / OFF of the first load (5A) and the second load (5B) is turned ON / OFF by switching the ON / OFF of the interlock switch because the ON / OFF is sequentially turned on / off.
There is a time lag during each time delay until switching to OFF,
The time delay can be easily detected. By measuring the time delay and by monitoring the ON / OFF switching sequence, it is possible to grasp the abnormal tendency of the contact and detect the abnormality.

(6) The apparatus further includes a document scanner (10) for reading an image of a document to generate image data; and
The image forming apparatus according to (5) above, further comprising means (53) for processing the image data into image data for forming an electrostatic latent image on the photoconductor.

According to this, in the digital copying apparatus, the action and effect of the above (5) can be obtained similarly.

(7) OFF / O linked with opening / closing of the cover
N interlock switch (73), a plurality of electric relays (86, 8) operated by the power line (+ 24V) in which the switch is inserted, and contacts of the switch (73) and the relays (86, 8) In a power supply device having an interlock circuit in which each load is connected to the rear stage, the output of the relay (86) in the front stage is connected to the relay (8) in the rear stage on the circuit, and the relay is opened and closed by the cover opening / closing operation. When the switch (73) is turned OFF / ON, the plurality of relays (86, 8) are sequentially turned OFF / ON, the power feeding device.

According to this, a plurality of relays (86, 8)
However, since the switch (73) is turned ON / OFF sequentially with the ON / OFF of the switch (73), the switch (7
From the ON / OFF switching of 3), the relay contact O
There is a time lag between each time delay until N / OFF switching, which makes it easier to detect the time delay, and by measuring the time delay and by monitoring the ON / OFF switching sequence, It is possible to understand the abnormal tendency of and detect abnormalities.

Other objects and features of the present invention will become apparent from the following description of embodiments with reference to the drawings.

[0034]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the appearance of a multi-function copying machine according to one embodiment of the present invention. This multi-function copying machine is roughly composed of an automatic document feeder [ADF] 30, an operating section 20, a color scanner 10, a color printer 100, and a relay unit 3.
2, a finisher 34 with a shift tray capable of stacking a large amount of stapler and image-formed paper, a double-sided reversing unit 33, a paper feed bank 35, and a large-capacity paper feed tray 3
Each of the 6- and 1-bin discharge trays 31 is configured.

FIG. 2 shows the configuration of the color printer 100. Reference numeral 101 denotes a flexible photoconductor belt. The photoconductor belt 101 is provided between the rotating rollers 102 and 3 and is conveyed in the direction of arrow A (clockwise direction) in the figure by the rotational driving of the rotating roller 102. . In the figure, 104 is the photoconductor belt 101.
A charging charger 105 for uniformly charging the surface is shown in FIG.
It is a laser exposure device that is an image writing unit. Also,
In the drawing, 106 is a color developing device, 106a is magenta, 106b is cyan, 106c is yellow, and 106d.
Is a black developing unit.

Further, reference numeral 109 in the drawing denotes an intermediate transfer belt, and the intermediate transfer belt 109 is a rotating roller 110-112.
And is conveyed in the direction of arrow B (counterclockwise) in the figure by the rotational drive of the rotating roller 110. Photoconductor belt 1
01 and the intermediate transfer belt 109 are the photoconductor belt 101.
The contact is made by the unillustrated rotating roller portion. A bias roller 113 having conductivity is in contact with the back surface of the intermediate transfer belt 110 on the intermediate transfer belt 109 side of the contact portion under a predetermined condition.

The photoreceptor belt 101 is the charger 10
After being uniformly charged by 4, the laser exposure device 105 exposes it by scanning laser light modulated with an image recording signal. As a result, an electrostatic latent image is formed on the photoconductor belt 101. Here, the image recording signal for modulating the laser light is for each color (single color) obtained by decomposing a desired full-color image into magenta, cyan, yellow, and black (Bk) color information, and for one color. The formation of the electrostatic latent image and the development by the one for the color among the developing devices 106a to 106d are repeated for the number of colors (for example, magenta, cyan, yellow, and black, a total of four times). The developed images (toner images) developed are transferred to the intermediate transfer belt 9 in an overlapping manner.

That is, each monochromatic image (toner image) formed on the photosensitive belt 1 rotating in the direction of arrow A in the figure is an intermediate transfer belt rotating in the direction of arrow B in the figure in synchronization with the photosensitive belt 101. The magenta, cyan, yellow, and black single colors are sequentially superposed and transferred on 109 by a predetermined transfer bias applied to the bias roller 113. The magenta, cyan, yellow, and black images superimposed on the intermediate transfer belt 109 are fed from the paper feed cassette 116 a of the paper feed tray 116 to the paper feed roller 117 and the conveyance roller pair 1.
18a, 118b, registration roller pair 119a, 119
The image is collectively transferred onto the transfer sheet conveyed to the transfer roller 114 via b. After the transfer is completed, the toner image on the transfer paper is fixed (heat-pressed) to the transfer paper by the fixing device 120. As a result, a full-color image is completed, and the transfer paper is ejected to the paper ejection stack unit 122 via the paper ejection roller pairs 121a and 121b.

Reference numeral 107 in the drawing denotes a photosensitive belt 101.
Is a cleaning blade for wiping off the toner on the photoconductor belt 101, and a cleaning blade 115 in the figure is a cleaning device for the intermediate transfer belt 109.
The cleaning brush 115a of 15 is held at a position separated from the surface of the intermediate transfer belt 110 during the image forming operation, and is abutted on the surface of the intermediate transfer belt 110 after the formed image is transferred onto the transfer paper.

Further, the photosensitive belt 101, the charging charger 104, the intermediate transfer belt 109, and the cleaning device 1
07 and 115 are integrally assembled into a process cartridge to form a unit.

Reference numeral 108 denotes a toner adhesion amount sensor for detecting the toner adhesion amount on the photosensitive belt 101. The toner adhesion amount sensor 108 used this time has a voltage V of a level corresponding to the amount of light received by the photodiode, in which the light emitting portion is an infrared light emitting diode and the diffuse reflection light receiving portion is a photodiode.
s, that is, a sensor that generates and outputs a detection signal, that is, a toner density sensor that measures the amount of diffuse reflected light.

Inside the fixing roller of the fixing device 120,
There is a fixing heater (halogen lamp) 123C, and the fixing energizing circuit 85 (FIG. 4) energizes the fixing heater 123C, whereby the fixing heater 123C generates heat and infrared rays are generated to heat the fixing roller.

FIG. 3 shows an outline of an electric system of the copying machine shown in FIG. One MPU (Micro Processing Unit) 51 on the main control board 50 is provided in the copier mechanical control unit, that is, the main part of image reading and image forming process control.
And one CPU (Center Proc
essing Unit) 12 is used. The MPU 51 controls the image forming sequence, fixing control, and system-related control by C
The PU 12 performs scanner-related control. MPU
51 and the CPU 12 are connected by an image data interface and a serial interface.

Further, in FIG. 3, reference numeral 20 denotes an operation unit, 70
Is an input / output I / F (interface) board equipped with an input / output electric circuit, and 92 is an L for controlling a laser beam for image exposure.
A D control plate, 41 is a paper feed control plate, 13 is a reading control plate on which a CCD is mounted, and 90 is a mother board.

Reference numeral 60 denotes a printer controller (board) for controlling a printer function for printing a host document such as a personal computer or a word processor and a combined operation mode of copying, facsimile and printer. Reference numeral 91 denotes an application expansion unit for realizing a composite function, which is a facsimile control unit (FCU) equipped with a FAX function. Reference numeral 80 is a DC power supply / AC control board.

FIG. 4 shows the fixing heater 1 from the power supply unit 80.
23C, I / O control board (input / output interface) 7
0, a main control board (main controller) 50, an outline of a power supply system to the mother board 90 and the printer controller 60, and an outline of the printer controller 60.

Referring to FIG. 4, an MPU 51, a CPU peripheral ASIC (Application Specific IC) 54, and an image processing A are provided in a main control board 50 for controlling the image forming process.
There is an I / F (interface) 52 having an interface function with the SIC 53 and the printer controller 60 and a compression / expansion function of image data.

The printer controller 60, which controls the system, includes a peripheral ASIC 64 having an interface between the MPU 61 and the main control board 50 for realizing a composite function, a communication function with the operation unit, and a memory control function, and others. is there.

A document scanner 10 for optically reading a document
In the reading unit, the light reflected by the lamp with respect to the original is condensed on the light receiving element by the mirror and the lens.
The light receiving element (CCD) is in the sensor board unit (SBU) 13, and the image signal converted into an electric signal in the CCD is converted into a digital signal, that is, read image data on the SBU 13, , SBU 13 is output to the image processing ASIC 53 on the main control board 50.

The image data read from the SBU 13 is transferred to the image processing ASIC 53, and the image processing ASIC 53 is transferred.
Corrects signal deterioration (signal deterioration of scanner system: distortion of read image data due to scanner characteristics) due to quantization into an optical system and a digital signal, and transfers the image data to the printer controller 60. Write to memory MEM65.
Alternatively, the printer 10 may be subjected to processing for printer output.
0 to the LD control plate 92.

That is, the image processing ASIC 53 outputs a job for storing the read image data in the memory MEM65 for reuse and a video data control (VDC) on the LD control board 92 without storing the read image data in the memory MEM65. Then, there is a job to output an image with the laser printer function. As an example of storing in the memory MEM65, when a plurality of originals are copied, the scanner 10 is operated only once, the read image data is stored in the memory MEM65, and the stored data is read out multiple times. . As an example in which the memory MEM65 is not used, when copying only one original, it is sufficient to process the read image data as it is for printer output, and therefore it is not necessary to write to the memory MEM65.

First, when the memory MEM65 is not used,
The image processing ASIC 53 performs image reading correction on the read image data and then performs image quality processing for conversion into area gradation. The image data after the image quality processing is transferred to VDC on the LD control board 92. With respect to the signal changed to the area gradation, the post-processing regarding the dot arrangement and the pulse control for reproducing the dots are performed by VDC, and the reproduced image is formed on the transfer paper by the laser printer function.

In the case where additional processing such as rotation in the image direction and image composition is carried out when the image data is stored in the memory MEM65 and read from the memory MEM65, the image data subjected to the image reading correction is stored in the image memory of the printer controller 60. It is sent to the peripheral ASIC 64 having the access control function. Here, the image data and the access control of the memory module MEM65 are controlled by the control of the MPU 61 according to the operation program stored in the flash EEPROM, and the print data of the external personal computer PC is expanded (character code / character bit conversion). , Compresses / decompresses image data for effective use of memory. The data sent to the peripheral ASIC 64 is stored in the MEM 65 after data compression, and the stored data is read out as necessary. Read data is expanded,
The original image data is returned to the image processing ASIC 53 from the peripheral ASIC 64.

When it is returned to the image processing ASIC 53, image quality processing is performed there and pulse control by VDC on the LCD control board 92 is performed, and a visible image (toner image) is formed on the transfer paper by the laser printer function.

The FAX transmission function, which is one of the composite functions,
The image data read by the original scanner 10 is subjected to image processing ASI.
The image is read and corrected at C53 and transferred to the FAX control unit (FCU) 91. The FCU 91 converts the data to the public line communication network and transmits it to the communication network as FAX data. For FAX reception, line data from the communication network is converted into image data by the FCU 91, and image processing ASI is performed.
Transfer to C53. In this case, no special image quality processing is performed,
Dot rearrangement and pulse control are performed in VDC on the LCD control plate 92, and a visible image is formed on the transfer paper by the laser printer function.

The MPU 51 of the main control board 50 controls the flow of image data and the MPU of the system controller 60.
U61 controls the entire system and manages activation of each resource. The function selection of this digital multi-function copying machine is selected and input through the operation unit 20, and the processing contents such as the copy function and the FAX function are set.

The power supply of the printer controller 60 is + 5VE which is in the energized state even in the sleep mode. The main control board 50 is supplied with + 5V, which is turned off in the sleep mode. The I / O control board 70 is supplied with + 5V and + 24V, which are also turned off in the rest mode.

The DC power source 80 has a converter output of +2.
Switch 8 for 4V and + 5VE (voltage of + 5V) respectively
3, 84 are connected. These switches 83, 8
A control signal for turning on / off the No. 4 is given from the printer controller 60 to the switches 83 and 84. When shifting to the sleep mode for energy saving, the printer controller 60 turns off both the switches 83 and 84 by this control signal.

The target temperature of the fixing control 85 is set to the fixing operation temperature determined in the fixing process of the transfer paper on which the toner image is transferred, and the temperature of the fixing roller is maintained there. Substantially delayed in response to a copy start or print command. Standby mode that can start image formation without time,
In the printer controller in the low power mode in which the target temperature is set to 80% of the fixing operation temperature in order to reduce the power consumption and other conditions are the same as those in the standby mode and the operation mode can immediately return to the standby mode. 60
Turns on both the switches 83 and 84 by the control signal.

That is, in the sleep mode, the switch 83,
When 84 is off, the printer controller 60 and the operation unit 2
0, + 5VE is continuously applied to the minimum number of electric elements or circuits for detecting the action of an operator, which indicates the possibility of using a copying machine, or the detection of the print command of a personal computer PC, for detecting the opening / closing of a pressure plate. In the printer controller 60,
+ 5VE is continuously applied to the circuit which waits for the detection and responds to it, the circuit which turns on the switches 83 and 84, and the memory which stores the data required to be held in a nonvolatile manner.

In the low power mode, power is supplied to all of them, and only the set temperature of the fixing heater 123C is lowered.

The MPU 61 of the printer controller 60 controls the analysis and display of the key-in data from the operation unit 20.
And the interface with the operation unit 20 is the peripheral ASI.
C64 is in charge. Peripheral ASIC 64 and operation unit 2
In this embodiment, 0 is connected to the mother board 90 via the main control board 50 and the scanner control board 11. Similar to the operation unit 20, the printer controller 60 is connected with a pressure plate open / close detection (not shown) via the mother board 90, the main control plate 50, and the scanner control plate 11.

The pressure plate opening / closing detection is a detection switch for detecting the opening / closing of the ADF 30 when the ADF 30 is connected to the scanner, and a detection switch for detecting the opening / closing of the pressure plate for pressing the document when the ADF 30 is not attached. . In any case, the pressure plate opening / closing detection generates a signal indicating whether the pressure plate for pressing the ADF or the document is open,
This is given to the peripheral ASIC 64 of the printer controller 60 via the scanner control board 10, the main control board 50, and the motherboard 90 in any of the image processing operation state, the standby mode, the low power mode, and the sleep mode, and the MPU 61 is provided. Read this signal. The power source (+ 5VE) for expressing a signal indicating whether the open state or the power source (+ 5VE) for detecting a turn-on of the input key of the operation unit 20 and generating a detection signal includes a motherboard 90, a main control board 50, and a scanner. The process controller 60 gives the open / close detection switch and the operation unit 20 via the control plate 10.

When equipped with the ADF 30, it is connected to the scanner control board 11. The detection signal of the document sensor that detects whether there is a document on the document table of the ADF 30
A peripheral AS of the printer controller 60 via the scanner control board 10, the main control board 50, and the motherboard 90.
It is given to the IC 64 and the MPU 61 reads this signal. A power supply (+ 5VE) for the document sensor to generate a detection signal indicating the presence or absence of a document is also supplied from the process controller 60 to the document sensor via the mother board 90, the main control plate 50, and the scanner control plate 10.

DC power supply / AC control board 80 SW83, 8
4 and an input / output I / F board 7 to which many electric loads are connected
In each of the + 24V power supply line and the + 5V power supply line between 0, the contacts of each set of the dual electric relay 86 having two sets of contacts are inserted. + 24V power supply line is relay contact a
Then, the + 5V power supply line is opened and closed by the relay contact b. The output voltage of SW83 + 24V is applied to the electric coil of the relay 86 through the door switch 73. There is an electric relay (not shown) inserted in the commercial AC voltage line in the fixing energizing circuit 85 for supplying the commercial AC to the fixing heater 123C, and the electric coil of this electric relay also has the output voltage of the SW83 + through the door switch 73.
24V is applied.

The door switch 73 is an interlock switch which is turned off by opening the front door of the printer 100 and turned on by closing the front door. When opening the electric relay of the DC power supply / AC control plate 80 by opening a side door or a cover in addition to the front door, a switch that is opened / closed by opening / closing those doors or covers is a door switch. 73 and each electric relay are inserted in series.

FIG. 5 shows the first electric relay 86 and the second electric relay of the interlock circuit including the door switch 73 and the electric relays 86 and 8 on the electric circuit system shown in FIG.
The circuit structure which detects the opening delay of the contact piece a of the electric relay 8 is shown. A door switch 7 is connected to the load C which is the step-down power supply circuit 5.
+ 24V is applied via 3, but the input / output I / F 71
The load A, which is the motor driver 5A above, is applied with + 24V via the contact a of the first electric relay 86, and the load B, which is also the solenoid driver 5B on the input / output I / F 71, is 2 + 24V is applied via the contact a of the electric relay 8.

The first electric relay 86 is turned ON / OFF in conjunction with the opening / closing of the cover door (not shown) of the printer 100.
The coil voltage is + 24V into which the door switch 73 is inserted, and the load A (5A) and the electrolytic capacitor 6B are connected to the output terminal thereof. This electrolytic capacitor 6
B is a bypass capacitor (bypass capacitor) for power decoupling of the load A (suppressing fluctuations in power supply voltage and suppressing noise). Furthermore, the drive coil of another second electric relay 8 is also connected to the output line of the first electric relay 86, and the output end of the second electric relay 8 is
Similarly, the load B (5B) and the electrolytic capacitor 6c are connected. The electrolytic capacitor 6c serves as a decap for decoupling the power supply of the load B (5B).

The operation of this circuit configuration will be described below.
First, by closing the cover door (not shown) that has been opened, the door switch 73 is turned on, and +24 V is supplied to the coil of the first electric relay 86. Along with this, the contacts a and b of the first electric relay 86 are closed (closed: on), that is, closed, and + 24V supply to the load A (5A) starts. To be precise, before the + 24V supply to the load A (5A), the decoupling electrolytic capacitor 6B starts to be charged, the voltage rises according to the charging condition, and when the charging is completed, the potential becomes the same as + 24V of the supply source. Become. During this period, the time is in the order of ten and several microseconds to several tens of microseconds, though it depends on the circuit constant including the capacitor capacity and the load system. During that time, the voltage applied to the drive coil of the second electric relay 8 connected to that line does not rise sufficiently, and to be exact, when it rises to the operating voltage (generally a voltage slightly lower than + 24V), For the first time, the contact a of the second electric relay 8 is closed, the charging operation to the decap decap 6C is started, and when the charging is completed, + is applied to the load B (5B).
24V supply starts.

By these operations, the first electric relay 86
And the second electric relay 8 is sequentially turned on without intervention such as software control. Note that this characteristic is effective even when OFF, and when the first electric relay 86 at the previous stage is OFF, the second electric relay 8 at the next stage is ON while the electrolytic capacitor 6B is discharging, and the voltage is to a certain extent. When it goes down, the second electric relay 8 is turned off, and the relays connected to the subsequent stage are sequentially turned off.

In FIG. 1, a relay having a + 24V output with one circuit is used for explanation, but a relay with two circuits can of course have this configuration. In this case, it suffices to gradually connect to the one with the higher voltage or the one with the larger capacitance of the decoupling capacitor. The point is that the charging time should be longer.

According to the configuration of FIG. 5, an open / close detection circuit is further connected to the circuit for performing the sequential ON / OFF operation, and the state of the line to which the loads A (5A) and B (5B) are connected is determined. Main control board 5 for monitoring
0 is connected to the input port of MPU 51.

By the way, the relay contact does not suddenly weld, but the magnitude of the inrush current value and d of the inrush current.
The contact transfer gradually occurs due to the magnitude of the I / dt, the value of the steady-state energizing current, and the like. In other words, the shape of the contact itself changes in the direction in which the gap between the contacts shrinks, and the contact eventually melts and does not turn off. No, I turned it off
An abnormal tendency appears such that F does not occur.

This is the ON / OF of the power supply voltage shown above.
This means that an error will occur in the F sequence,
If the MPU 51 monitors this sequence, it is possible to manage the abnormal state of the contact. The sequence of both load lines at the time of ON is not reversed, or the sequence is correct, but the delay time is not too wide, or OF
Check if the sequence of both load lines at F is reversed.
The sequence is correct, but whether the delay time is too long is judged by software monitoring. Note that depending on the operation speed of the MPU 51, if the processing using the normal input port is not in time, the processing is immediately performed as an interrupt input. Alternatively, a supervisory circuit using discrete digital logic circuits is used.

When the above abnormality is finally detected, the operator is notified of the abnormality by displaying the content of the abnormality on the display panel for the operator, and the equipment is stopped to prompt the replacement of the relay parts. . Since the operator protection may not work, the equipment cannot be operated until the parts are replaced.

In FIG. 6, the cover door is opened and the door switch 73 is switched from ON to OFF, whereby the first signal i1A is switched from the high level H to the low level L, and in response thereto, the MPU 51 executes. The contents of the interrupt processing CAMA when the door is opened are shown below.

When the operator opens the front door of the printer 100, the door switch 73 changes from closed to open, which causes the signal i1A to fall from H to L.
The process proceeds to the interrupt processing CAMA, and each time counting using the time counters t1 and t2 is started (11). Next MPU
51 waits for the output signal i2 of the first electric relay 86 to fall to L (12, 13). While waiting, it is checked whether the time count value t1 using the time counter t1 has exceeded a threshold value T1 for determining the open movement abnormality of the contact pieces a and b (14).

When t1> T1, the MPU 51 determines that the first
The open error information of the first relay 86 is written in the error register ER1, and the electric relay 8 is displayed on the display panel of the operation unit 20.
The open movement abnormality of 6 is displayed (14). Then, the time counting t1 using the time counter t1 is stopped (15).

Before t1> T1, the first electric relay 86
When the output signal i2 of the signal falls to L, the MPU 51 stops the time measurement t1 using the time counter t1 ((1
5), wait for the output signal i3 of the second electric relay 8 to fall to L (16, 17). While waiting, it is checked whether the time value t2 using the time counter t2 has exceeded a threshold value T2 for determining the open movement abnormality of the contact piece a (17).

When t2> T2, the MPU 51 makes the second
The open error information of the second relay 8 is written in the error register ER2, and the open movement abnormality of the electric relay 8 is displayed on the display panel of the operation unit 20 (18). Then, the time counting t2 using the time counter t2 is stopped (19).

When the output signal i3 of the second electric relay 8 falls to L before t2> T2, the MPU 51 stops the time counting t2 using the time counter t2 (19).
Then, it is checked whether t1> T1 (20), and if so, the open error information of the first relay 86 is written in the first error register ER1, and the open movement abnormality of the electric relay 86 is displayed on the display panel of the operation unit 20. Is displayed (22). t1 ≦ T
When it is 1, the first error register ER1 is cleared, and the display of the open movement abnormality of the electric relay 86 on the display panel of the operation unit 20 is erased (21). Moreover, it is checked whether t2> T2 (23), and if so, the open error information of the second relay 8 is written in the second error register ER2,
An open movement abnormality of the electric relay 8 is displayed on the display panel of the operation unit 20 (25). When t2 ≦ T2, the second error register ER2 is cleared, and the open movement abnormality display of the electric relay 8 on the display panel of the operation unit 20 is erased (24).

When a discrete digital logic circuit is used for the above-mentioned relay opening abnormality tendency monitoring, for example, as shown by a virtual line (two-dot chain line) in the block of the MPU 51 of FIG. At the fall of H to L, the flip-flop F is set to start counting up the clock pulse CLK by the counter Co, and at the fall of the second signal i2 from H to L, the count data t1 is stored in the first latch L1. Latch the third signal i3 from H to L
The count data t2 is latched in the second latch L2 at the falling edge of, and when t1> T1, the output of the comparator c1 is set to an abnormal display level, and the first electric relay 86 is opened on the display panel of the operation unit 20. A movement abnormality is displayed, and if t2> T2, the output of the comparator c2 is set to an abnormality display level, and the open movement abnormality of the second electric relay 8 is displayed on the display panel of the operation unit 20.

In FIG. 7, the cover door is closed and the door switch 73 is switched from OFF to ON, whereby the fourth signal i1B is switched from the high level H to the low level L, and in response thereto, the MPU 51 executes. The contents of the interrupt processing CAMB when the door is closed are shown.

When the operator closes the front door of the printer 100, the door switch 73 changes from open to closed, and when the fourth signal i1B falls from H to L, the MPU5
1 proceeds to the interrupt processing CAMB, and the time counter t1
Start each timing using 31 and t2 (31). Next, the MPU 51 outputs the output signal i2 of the first electric relay 86 at H level.
Wait to get up (32, 33). While waiting, it is checked whether the time count value t1 using the time counter t1 has exceeded a threshold value T1 for determining the closed movement abnormality of the contact pieces a and b (34).

When t1> T1, the MPU 51 determines that the first
The closing error information of the first relay 86 is written in the error register ER1, and the electric relay 8 is displayed on the display panel of the operation unit 20.
The closing movement abnormality of 6 is displayed (34). Then, the time counting t1 using the time counter t1 is stopped (35).

Before t1> T1, the first electric relay 86
When the output signal i2 of the signal rises to H, the MPU 51 stops the time measurement t1 using the time counter t1 (3
5), wait for the output signal i3 of the second electric relay 8 to rise to H (36, 37). While waiting, it is checked whether the time value t2 using the time counter t2 has exceeded the threshold value T2 for determining the closed movement abnormality of the contact piece a (37).

When t2> T2, the MPU 51 makes the second
The closing error information of the second relay 8 is written in the error register ER2, and the closing movement abnormality of the electric relay 8 is displayed on the display panel of the operation unit 20 (38). Then, the time t2 using the time counter t2 is stopped (39).

When the output signal i3 of the second electric relay 8 rises to H before t2> T2, the MPU 51 stops the time counting t2 using the time counter t2 (39).
Then, it is checked whether t1> T1 (40), and if so, the closing error information of the first relay 86 is written in the first error register ER1, and the closing movement abnormality of the electric relay 86 is displayed on the display panel of the operation unit 20. Is displayed (42). t1 ≦ T
When it is 1, the first error register ER1 is cleared, and the abnormal display of the closed movement of the electric relay 86 on the display panel of the operation unit 20 is erased (41). Further, it is checked whether t2> T2 (43), and if so, the closing error information of the second relay 8 is written in the second error register ER2,
An abnormal closing movement of the electric relay 8 is displayed on the display panel of the operation unit 20 (45). When t2 ≦ T2, the second error register ER2 is cleared, and the display of the closing movement abnormality of the electric relay 8 on the display panel of the operation unit 20 is erased (44).

When a discrete digital logic circuit is used for the above-mentioned relay closing abnormality tendency monitoring, a virtual line (two-dot chain line) is provided in the block of the MPU 51 shown in FIG.
A circuit similar to the logic circuit shown in is used.

[0090]

Since the plurality of electric relays (86, 8) are turned ON / OFF sequentially with the ON / OFF of the interlock switch (73), the ON / OFF of the interlock switch (73) is switched. To the ON / OFF switching of the contact of each relay, there is a time lag between each delay, which makes it easy to detect the time delay. By measuring the time delay, the ON / OFF switching sequence can be changed. By monitoring the, it is possible to grasp the abnormal tendency of the contact and detect the abnormality.

[Brief description of drawings]

FIG. 1 is a plan view showing the external appearance of a digital copying machine equipped with a power supply device according to a first embodiment of the present invention.

FIG. 2 is a vertical cross-sectional view showing an outline of the mechanism of the color printer 100 shown in FIG.

3 is a block diagram showing a system configuration of an electric system of the digital copying machine shown in FIG.

4 is a block diagram showing an outline of a configuration of a DC power supply 80 shown in FIG.

5 is a door switch 73 on the electric circuit shown in FIG.
FIG. 9 is an electric circuit diagram showing a circuit configuration of an interlock circuit including the electric relays 86 and 8 for detecting an opening delay of the contact pieces a and b of the electric relays 86 and 8.

6 is a door switch 73 of the MPU 51 shown in FIG.
5 is a flowchart showing the contents of interrupt processing when is opened.

7 is a door switch 73 of the MPU 51 shown in FIG.
6 is a flowchart showing the contents of interrupt processing when is closed.

[Explanation of symbols]

100: Color printer 73: Door switch 86, 8: Electric relay a, b: contact piece 5,56,57: Inverter

Claims (6)

[Claims] 1. An interlock switch, a first electric relay that is switched from off to on by switching the interlock switch from off to on, and switching of a relay contact of the first electric relay from open to closed. A second electric relay that is switched from off to on by an electric power source, and supplies power to the first load via a relay contact of the first electric relay,
Power to the second load via the relay contacts of the electrical relay,
A power supply device having an interlock circuit. 2. The opening monitoring means for monitoring whether the relay contact of the electric relay is switched from off to on within a set time after the interlock switch is switched from on to off. The power supply device described. 3. A closure monitoring means for monitoring whether or not a relay contact of the electric relay is switched from off to on within a set time after the interlock switch is switched from off to on. Alternatively, the power supply device according to claim 2. 4. A third device through the interlock switch.
A power supply device having the interlock circuit according to claim 1, which supplies power to a load. 5. A transfer paper which forms an electrostatic latent image on a photoconductor, visualizes the electrostatic latent image as a toner image by a developing device, and directly or indirectly through the intermediate medium. In an image forming apparatus for transferring to an image forming apparatus, an interlock switch that is opened by opening a door or a front cover of the image forming apparatus and closed by closing the same is switched from off to on by forming an image by forming an interlock switch. First to power the first load of the device
An electrical relay; and a second electrical contact of the image forming apparatus, which is switched from off to on by switching the relay contact of the first electrical relay from open to closed.
An image forming apparatus comprising: a second electric relay for supplying power to a load. 6. The apparatus further comprises a document scanner for reading an image of a document to generate image data; and means for processing the image data into image data for forming an electrostatic latent image on the photoconductor. The image forming apparatus according to claim 5, further comprising: