JPH0819163A - Facsimile equipment - Google Patents

Abstract

PURPOSE:To cut off supply of abnormal current to a facsimile equipment by detecting abnormal current in the standby condition and the operating condition of the facsimile equipment. CONSTITUTION:In the standby condition of a facsimile equipment, a relay R1 is connected with a terminal B. When abnormal current passes through a fuse F2 for more than a fixed duration, the F2 is melted. When the facsimile equipment is in an operating condition, the real R1 is changed over and connected with a terminal A. When abnormal current passes through the facsimile equipment in the operating condition, a fuse F1 is melted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to detection of abnormal current in a facsimile machine.

[0002]

2. Description of the Related Art When an abnormality occurs in a power source due to damage of parts of a power source section or lightning strike during the operation of a facsimile apparatus, an abnormal current flows in the facsimile apparatus. If an abnormal current flows in the facsimile machine, the facsimile machine may ignite or smoke.

In order to prevent such ignition and smoke,
A conventional facsimile machine has a fuse. When an abnormal current flows through the facsimile, the fuse is blown. When the fuse is blown, the power supply and the facsimile machine are cut, and the operation of the facsimile machine is stopped.

[0004]

Normally, the value of the power supply current supplied to the facsimile machine in the standby state is greatly different from the value of the power supply current supplied to the facsimile machine in the operating state. Nevertheless, the fuse of the conventional facsimile apparatus is designed to blow when the maximum rated current in the operating state flows. However, a component such as a screw is left on the substrate of the facsimile machine, a short circuit occurs at that portion, and an abnormal current may flow in the facsimile machine even in the standby state.

Therefore, when an abnormal current flows in the facsimile machine in the standby state, the abnormality cannot be detected and the abnormal current continues to flow in the facsimile machine. Since the facsimile apparatus is placed in a standby state for most of the time, the abnormal current as described above flows in the facsimile apparatus for a long time without being detected, which causes a failure of the facsimile apparatus.

[0006]

In order to solve the above problems, the invention of claim 1 is a facsimile apparatus provided with a detection device for detecting an abnormal current of a power supply, and the detection device is a facsimile device. First detecting means for detecting an abnormal current in an operating state of the apparatus, second detecting means for detecting an abnormal current in a standby state, and switching means for switching between the first detecting means and the second detecting means. It is characterized by having.

According to a second aspect of the present invention, when the switching means of the detection device receives a signal from any one of the key input section and the network control section of the facsimile apparatus, the second detection means outputs the first detection means. Is switched to, and after the operation of the facsimile apparatus is completed, the first detecting means is switched to the second detecting means.

The invention according to claim 3 is characterized in that each of the first detecting means and the second detecting means of the detecting device is a fuse, and the fuse is a delay type fuse.

[0009]

As described above, according to the invention of claim 1, the first
The detecting unit and the second detecting unit can detect the abnormal current in the operating state and the standby state of the facsimile apparatus, respectively. Then, the switching means can switch the two detecting means as needed to properly prevent the failure of the facsimile apparatus.

According to the second aspect of the present invention, when the facsimile apparatus is in the operating state, the switching means is switched from the second detecting means side to the first detecting means side so that the abnormal current in the operating state can be detected. become. Further, in the standby state, the switching means is switched from the first detecting means side to the second detecting means side,
The abnormal current in the standby state can be detected.

Further, according to the third aspect of the invention, since the fuses provided in the first detecting means and the second detecting means are of the delay type, the value of the current increases momentarily, and then the normal value increases. In the case of returning to a proper current value, the fuse is not blown and the facsimile machine does not stop.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG.
FIG. 1 is a block diagram showing a circuit configuration of a facsimile apparatus according to an embodiment of the present invention. The main controller (CPU) 1 is for controlling the operation of the entire facsimile apparatus. The CPU 1 displays a recording section 2 for printing out image data transmitted from the other party, a reading section 3 for reading the front surface of the original document to be transmitted to the other party, and a message regarding the operation of the facsimile apparatus. The display unit 4 is connected.

The CPU 1 has a ROM 5 in which programs and various data for controlling various operations of the facsimile machine are stored, and an RA in which image data is temporarily stored.
The M6 and the key input unit 7 for inputting various signals such as the fax number of the other party are connected. Further C
The PU 1 is connected to a modem 8 that modulates / demodulates image data to be transmitted / received.

The modem 8 is connected to a network control unit (NCU) 9 having a function of detecting transmission of dial pulses corresponding to the fax number of the other party and an incoming call from the other party. The NCU 9 is connected to a line.

The power supply circuit 10 is a circuit for rectifying the voltage of a commercial power supply which is an AC power supply and supplying a stable voltage to the facsimile apparatus. The detection device 11 is a device for detecting an abnormal current flowing in the facsimile device,
It is connected to the power supply circuit 10.

The detection device 11 is provided with two fuses F1 and F2 having different maximum rated current values in parallel. The relay R1 is for switching the connection between the fuse F1 and the commercial power source and the connection between the fuse F2 and the commercial power source. Outlet 12
It is for connecting the commercial power supply and the detection device 11.

When the facsimile machine is in the standby state,
The relay R1 is connected to the B terminal, and the current from the power supply passes through the fuse F2 and is supplied to the facsimile apparatus. In this state, if an abnormal current flows in the facsimile device for a certain period of time or more, the fuse F2 is blown and the current from the outlet 12 to the facsimile device is cut off.

In the facsimile apparatus in the standby state, the NCU 9 detects the fax number from the other party,
Alternatively, when a signal such as the fax number of the other party is input from the key input unit 7, the CPU 1 discriminates the input signal and switches the relay R1 from the B terminal side to the A terminal side. As a result, the current from the power source passes through the fuse F1 and is supplied to the facsimile apparatus.

In the state where the relay R1 is switched as described above, if an abnormal current flows in the facsimile apparatus for a predetermined time or more, the fuse F1 is blown and the current from the outlet 12 is cut off. The maximum rated current value of the fuse F1 is about 1.5 to 2 times the current value when the maximum current flows through the facsimile device. In this embodiment, since the power supply is momentarily cut off when switching the relay R1,
It is necessary to provide the power supply circuit 10 with a battery or the like that supplies power to the CPU 1 or the like during this momentary interruption.

FIG. 2 is a block diagram showing the circuit arrangement of a facsimile apparatus equipped with a detection device according to another embodiment of the present invention. A fuse F3 and a fuse F4 are provided in series in the detection device 11 provided between the power supply circuit 10 and the outlet 12. In this case, the fuse F3 is a fuse that detects an abnormal current in the standby state of the facsimile apparatus, and the fuse F4 is a fuse that detects an abnormal current in the operating state of the facsimile apparatus.

In the case of this embodiment, the relay R2 is provided between the terminals of the fuse F3. And the fuse F3
Since the fuse F4 and the fuse F4 are connected in series, the power source will not be momentarily cut off when the fuse F3 and the fuse F4 are switched.

When the facsimile machine is in the standby state,
The relay R2 is open, and the current from the outlet 12 passes through the fuses F3 and F4 and is supplied to the inside of the facsimile apparatus. At this time, in the facsimile machine,
When an abnormal current flows for a certain period of time or more, the fuse F3 is blown and the current from the outlet 12 to the facsimile machine is cut off.

When the NCU 9 detects a calling signal from the other party or a signal such as the fax number of the other party is input from the key input unit 7 in the facsimile apparatus in the standby state, the CPU 1 receives the input signal. Is determined and the relay R2 is closed. At this time, since the resistance of the relay R2 is smaller than the resistance of the fuse F3, the current from the outlet 12 passes through the relay R2 and the fuse F4 and is supplied into the facsimile apparatus.

With the relay R2 closed as described above,
When an abnormal current flows in the facsimile device for a certain period of time or more, the fuse F4 is blown and the current from the outlet 12 to the facsimile device is cut off.

[0025]

As described above, according to the present invention, the abnormal current of the facsimile machine is constantly detected by selectively using the two fuses provided in the facsimile machine and having different maximum current values. be able to. Therefore, when an abnormal current flows in the standby state or the operating state of the facsimile apparatus, one of the two fuses is blown, and it is possible to avoid a failure such as smoking or ignition of the facsimile apparatus due to the abnormal current.

Further, since the two fuses are of the delay type, the inrush current larger than the maximum rated current value generated when the power of the facsimile is turned on is momentarily generated by the facsimile machine. The above fuse does not blow out when it flows to the. Therefore, the current supplied from the commercial power source to the facsimile device is prevented from being accidentally cut off when the facsimile device is operating or waiting in a normal state.

[Brief description of drawings]

FIG. 1 is a block diagram showing a circuit configuration of a facsimile apparatus according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a circuit configuration of a facsimile apparatus according to another embodiment of the present invention.

[Explanation of symbols]

 1 CPU 2 Recording part 3 Reading part 7 Key input part 8 Modem 9 NCU 10 Power supply circuit 11 Detection device 12 Outlet R1, R2 Relay F1-F4 Fuse

Claims (3)

[Claims] 1. A facsimile apparatus comprising a detection device for detecting an abnormal current of a power supply, said detection device comprising a first detection means for detecting an abnormal current in the operating state of the facsimile device, and a standby device for detecting the abnormal current. A facsimile machine, comprising: a second detecting means for detecting an abnormal current; and a switching means for switching between the first detecting means and the second detecting means. 2. The switching means of the detecting device switches from the second detecting means to the first detecting means when receiving a signal from any one of the key input section and the network control section of the facsimile apparatus, and the switching means of the facsimile apparatus. 2. The facsimile apparatus according to claim 1, wherein the first detecting means is switched to the second detecting means after the operation is completed. 3. The facsimile apparatus according to claim 1, wherein the first detecting means and the second detecting means of the detecting device are fuses, and the fuses are delay type fuses.