JP2002159143A - Power supply circuit and image forming apparatus having the circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power supply circuit which is low in cost, is simple in structure, does not need a large occupation space, and can avoid a sudden interruption of a power supply which causes the inconvenience and to provide an image forming apparatus having the power supply circuit. SOLUTION: If a controller 4 decides that a sudden interruption of a power supply causes the inconvenience, a relay 2 is made to operate (turned on) and a circuit connected in parallel with a switching circuit is closed. If it is decided afterwards that the interruption of the power supply does not cause the inconvenience, the operation of the relay 2 is discontinued. During the operation (ON) period of the relay 2, even if a user of an apparatus turns off a switch 1, as the circuit connected in parallel with the switching circuit 1 is closed, the power supply is not cut off. With such a constitution, the power supply circuit which is low in cost, is simple in structure, does not need a large occupation space, and can avoid the sudden interruption of the power supply which causes the inconvenience and an image forming apparatus having the power supply circuit can be provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a power supply circuit which maintains a current-carrying state even when power is suddenly cut off by a switch, and an image forming apparatus having the same.

[0002]

2. Description of the Related Art Normally, power is supplied to and cut off (ON / OFF) from various electric devices operated by electric energy.
The electric device is operated or stopped by operating the switch. In general electric equipment, the operation of the above-mentioned switch can be performed arbitrarily by a user.

[0003] However, some of the above-mentioned electric devices may be inconvenient if the switch is suddenly turned off during operation. For example, a case in which post-processing is performed after the operation, a case in which a high-speed reciprocating operation is being performed (scanner operation of the image control device, etc.), and a case in which a personal computer or the like is accessing the hard disk are exemplified.

As a technique for avoiding the above-mentioned disadvantages, the present applicant has proposed a technique for locking a switch.

[0005]

However, the above-described techniques have problems that they are costly, have a complicated mechanism, and require a large space.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and it is possible to avoid a sudden stop of a power supply at a low cost, with a simplified mechanism, and with a small space requirement. It is an object to provide a power supply circuit and an image forming apparatus having the same.

[0007]

In order to achieve the above object, a power supply circuit according to the first aspect of the present invention is configured such that a power supply is turned on / off (O
N / OFF), an energizing unit configured in parallel with the switch, and a controller unit for controlling the energizing unit. If the controller unit determines that inconvenience will occur when the power is cut off, Through which power can be supplied.

According to a second aspect of the present invention, in the power supply circuit of the first aspect, the energizing means is a relay whose relay contact is configured in parallel with the switch.

A power supply circuit according to a third aspect of the present invention is the power supply circuit according to the first aspect, wherein the energizing means is an energizing circuit in which a circuit is formed in parallel with a switch by a switching element.

[0010] The image forming apparatus according to the fourth aspect is the first aspect.
The power supply circuit according to any one of the above items 3 to 3 is provided.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a power supply circuit and an image forming apparatus having the same according to the present invention will be described in detail with reference to the accompanying drawings. 1 to 3 show an embodiment of a power supply circuit according to the present invention and an image forming apparatus having the same.

FIG. 1 is a circuit diagram showing a power supply circuit according to a first embodiment of the present invention. According to FIG. 1, an AC (Alternating current) power line is supplied to a DC (Direct current) power unit 3 through a switch 1.

When the switch 1 is in the ON state, the DC power supply unit 3 converts AC to DC and outputs it to the controller 4. The DC power is supplied not only to the operation of the controller 4 but also to the relay 2, the sensor 5, the solenoid 6, the clutch 7, the motor 8, and the operation unit 11 connected to the controller 4.
Also used to operate etc.

When the switch 1 is turned on or an input is made from the operation unit 11 thereafter, the controller 4 starts operating and operates the solenoid 6, the clutch 7, the motor 8 and the like while reading information from the sensor 5 and the like. Control it by stopping or starting.

At this time, depending on the sequence of various actuators and the output state of the sensor 5 and the like, the controller 4
However, if it is determined that inconvenience will occur if the power supply is suddenly cut off, the relay 2 is operated (ON). Then, the circuit connected in parallel with the switch circuit is closed. Then, if it is determined that it is safe to turn off the power, the relay 2 is stopped (OFF).

During the operation (ON) of the relay 2, even if the user of the device turns off the switch 1, the power supply is not cut off because the circuit connected in parallel with the switch circuit is closed.

In the initial state, since the switch 1 is OFF, no AC power is supplied to the DC power supply unit 3, and the controller 4 and the relay 2 do not operate. Therefore, this state is maintained until the switch 1 is turned ON by the operator.

Thereafter, when the switch 1 is turned on, D
AC power is supplied to the C power supply unit 3 and the controller 4 starts operating. If the controller 4 does not determine that there is no inconvenience even if the power is cut off suddenly, the AC power supplied to the DC power supply unit 3 is switched off while the relay 2 remains OFF. It can be shut off at any time by turning it off.

On the other hand, if the switch 1 is ON and the controller 4 determines that inconvenience will occur if the power supply is suddenly cut off, the relay 2 is turned ON and
The AC power supplied to the C power supply unit 3 cannot be cut off even if the switch 1 is turned off, and the power is supplied.

This state continues until the controller 4 determines that the power can be suddenly shut off. When the controller 4 determines that it is okay to turn off the power suddenly,
As soon as the relay 2 is turned off, the power is cut off.

FIG. 2 is a circuit diagram showing a power supply circuit according to a second embodiment of the present invention. The configuration of FIG. 2 differs from that of FIG. 1 in that a contact circuit of a relay 2 connected in parallel with a circuit of a switch 1 in FIG.
Is replaced by

The ON / OFF of the switching element is controlled by a photocoupler by a controller. The other description is the same as that of the first embodiment, and thus will be omitted.

FIG. 3 is a circuit diagram showing a power supply circuit according to a third embodiment of the present invention. The difference from FIG. 2 is that the power supply is a DC power supply such as a battery, and the power supply is directly supplied to the controller 4 without a DC power supply unit. The switching element is a switching circuit 2b using a transistor.

As described above, the power supply circuit according to the present invention is not limited to the embodiment, and various changes and devices can be easily considered. In the third embodiment, the power supply circuit described above is applied to an image forming apparatus.

In an image forming apparatus having a charging wire, such as a copier, a printer, a facsimile, etc., during the image forming process,
When a high voltage is applied to the charging wire, ozone is generated from the charging wire. If this ozone is left as it is, it will cause a nox to adhere to the charging wire or react with the photoreceptor, adversely affecting both.

Therefore, these image forming apparatuses are designed to have an air flow that diffuses ozone generated in the image forming process, or have a fan for diffusing ozone, and keep the fan running even after the image forming is completed. Etc. are performed.

Therefore, in these image forming apparatuses, if the power is shut off immediately after the image forming process, the charging wire and the photosensitive member are adversely affected, and the desired image quality cannot be obtained.

In order to solve such a problem of the image forming apparatus, an operator of the image forming apparatus turns off the switch for a certain period of time after a high voltage is applied to the charging wire during an image forming process or the like. An image forming apparatus including a power supply circuit, wherein the power supply circuit is configured not to shut off the power supply even if it is performed.

[0029]

As is apparent from the above description, according to the present invention, when the controller determines that inconvenience will occur if the power is cut off, the power is supplied also by the energizing means of the relay or the switching element. , Switch is OF
Even if the power is turned off, control can be performed so that the power is not cut off.

Therefore, for example, when various devices are performing post-processing after operation, during high-speed reciprocating motion (scanner operation of the image control device, etc.), or when a personal computer or the like is accessing the hard disk. This can prevent the power from being suddenly shut off.

With respect to the above example, the effects of reliably finishing post-processing after the operation of various devices, the effects of preventing device failure or damage due to runaway of a high-speed moving object, the destruction of a hard disk, and the This has the effect of preventing loss of storage. In addition, the present invention is more advantageous in terms of cost, a simple mechanism, and a small required space than the conventional switch locking type invention.

[Brief description of the drawings]

FIG. 1 shows a circuit diagram as a first embodiment of a power supply circuit according to the present invention.

FIG. 2 is a circuit diagram showing a power supply circuit according to a second embodiment of the present invention.

FIG. 3 shows a circuit diagram as a third embodiment of the power supply circuit according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Switch 2 Relay 3 DC power supply unit 4 Controller 5 Sensor 6 Solenoid 7 Clutch 8 Motor 11 Operation part

Claims (4)

[Claims] 1. A power supply device comprising: a switch for energizing / cutting off (ON / OFF) a power supply; energizing means configured in parallel with the switch; and a controller for controlling the energizing means. A power supply circuit, wherein when the controller unit determines that a problem occurs, the power supply circuit is set to a state in which power can be supplied through the power supply unit. 2. The power supply circuit according to claim 1, wherein said energizing means is a relay whose relay contact is configured in parallel with said switch. 3. The power supply circuit according to claim 1, wherein said energizing means is an energizing circuit in which a circuit is formed in parallel with said switch by a switching element. 4. An image forming apparatus comprising the power supply circuit according to claim 1. Description: