JPS60170867A - Interlock detecting circuit of copying machine - Google Patents

Abstract

PURPOSE:To select the source voltage of an interlocking circuit optionally by powering on a control system which is disconnected from the power source of an interlocking circuit through a photocoupler. CONSTITUTION:When the inspection door of the copying machine is closed, interlock switches 3 and 4 turn on to operate a relay 1, and also turn on the light emitting diode 10a of the photocoupler. A motor 2 is therefore supplied with specific electric power to rotate, and the internal resistance of a transistor (TR) 10b decreases to flow a specific current from a power source B1; and a voltage drop Vr is generated across a resistance 11 and supplied as an input signal, so that an inverter 7 generates an interlock detection signal. On the other hand, when the inspection door is opened during the operation of the copying machine, either or both of the switches 3 and 4 turns off and no current flows through the relay 1 and diode 10a, so that the relay 1 and diode 10a stop operating.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to an interface detection circuit for a copying machine in which an interlock circuit power supply can be separated from a logic circuit power supply.

[Prior art]

An example of a conventional copying machine interface detection circuit is shown in FIG. This interface detection circuit uses an excitation coil l connected to source B for the logic circuit.
a, and an excitation coil 1m, the motor 2
(for photoconductor drum drive, etc.).
A relay 1 equipped with a relay contact 1b that supplies V), interlock switches 3 and 4 connected in cascade between the other end of the excitation coil 1a and ground, and a relay connected between a power supply B and the interlock switch 3. A current-limiting resistor 5 connected to the other end of the resistor 5, a current-limiting resistor 6 connected to the other end of the resistor 6, and a voltage generated in response to the operation of the interlock switches 3 and 4 provided at the other end of the resistor 6 are input signals. and the inverted signal is OP
The copying machine is composed of an inno-nin tough that includes U, etc., and outputs control commands to a control section that controls the copying machine.

With the above configuration, inadvertent inspection and
In order to prevent clothing, fingers, etc. from getting caught in the rotating parts when the maintenance door is opened, interlock switches 3 and 4 are provided that operate in response to opening and closing of the door. Two switches are provided to prevent malfunction.
The contacts are turned off as soon as the door is opened. Normally, interlock switches 3 and 4 are closed, excitation coil 1m of relay l is energized, and relay contact 1
The normally open contact side of b is closed, and the shunt commercial power is applied to the motor 2. That is, as long as the interlock switches 3 and 4 are closed, the motor 2 is operated according to the control contents of the control section. Also, in this state, the connection point between resistors 5 and 6 is grounded, and the inverter 7
Since no input signal is applied to the output terminal, an output signal of '1' level is generated at the output terminal, and this becomes the interface detection signal.

On the other hand, when the door is opened, interlock switch 3 or 4 (or both) changes from on to off, power to excitation coil 1m is cut off, relay contact 1b is switched to the normally closed contact side, and motor 2 is power supply is cut off.

Therefore, even if clothes, fingers, etc. come into contact with the internal mechanism, accidents will not occur. Also, interlock switch 3
and 4 are turned off, a predetermined voltage is applied to the inverter 7 via the resistors 5 and 6, and the inverter 7
The ``O#O# level voltage is applied to the output terminal of the output terminal, and the interface detection signal disappears.

However, in the interlock detection circuit of conventional copiers, the power supply is connected to the control system via a resistor and a gate circuit.
It was not possible to separate the power supply for the relays and interlock switches, and it was not possible to arbitrarily select the power supply voltage for the interfaces and circuits. Although selection is possible within the voltage range in which voltage conversion is possible, the selection range is approximately 5V to 15V''C, so the selection range is small).

[Object and structure of the invention]

The present invention has been made in view of the above.

In order to be able to arbitrarily select the power supply voltage for the interlock circuit, the power supply for the control system is separated from the interface circuit, and a photocoupler is used that is activated by the activation of the interlock switch when the power is turned on.・The interface of the copier.

The present invention provides a detection circuit.

〔Example〕

Hereinafter, a detailed explanation will be given of the error detection circuit of a copying machine based on an error detection circuit.

FIG. 2 shows an embodiment of the present invention, and since the same reference numerals are used for the same parts as shown in FIG. 1, redundant explanation will be omitted. and a phototransistor 10b whose internal resistance decreases when receiving 10 m of light from the light emitting diode and causes a current to flow through the load. A photocoupler 10 is installed between the interface circuit and the input circuit. The feature is that the two circuits are separated in terms of direct current. Light emitting diode 10m is power supply B! The interlock switch 3 is connected between the relay 1 and the interlock switch 3 in such a direction that the interlock switch is energized and emitted light when each interlock switch is turned on. Further, the phototransistor 10b has a collector connected to a power source B!
are connected, and the emitters and ri are grounded via a load resistor 11 and are also connected to the input terminal of the inverter. The power supplies B1 and B3 are power supplies of different systems, and have power supply voltages corresponding to the voltage requirements of the circuits to which they are connected. Incidentally, the grounding terminals of the interlock switch 4 and the resistor 11 are individually connected to the grounding terminal of the own power source.

In the above configuration, when the inspection door of the copying machine is closed, interlock switches 3 and 4 are in the on state, relay 1 operates, and
10m of light emitting diodes emit light. As a result, a predetermined power is supplied to the motor 2 and the motor 2 is operated, and the internal resistance of the transistor 10b decreases, a predetermined current is passed from the power source B1 to the resistor 11, and a voltage drop Vr is applied to the resistor 11. The inverter 7, which receives this voltage r as an input signal, generates a voltage at the level 'l' as an interlock detection signal.

On the other hand, if the inspection door is opened while the copying machine is operating, one or both of interlock switches 3 and 4 (7) will be turned off, and no current will flow through relay 1 and light emitting diode 10m. Stop operation. As a result, the contacts of relay l open and the power supply to motor 2 is cut off, and the light emitting diode 10m stops emitting light, so the internal resistance of phototransistor 10b increases and current no longer flows through resistor 11. , the voltage drop V, disappears. Therefore, the movable parts inside the copying machine stop, the danger disappears, and the output voltage of the inverter 7 becomes @0# level, and the interface detection signal also disappears.

In the above embodiments, a photocoupler in which a light emitting part and a light receiving part are integrated is explained as an example, but they may be constructed as separate bodies. In short, any type of circuit may be used as long as the interlock circuit and the input circuit can be isolated in terms of direct current.

Further, although the interlock switch and the light emitting section of the 7-oto coupler are connected in series, they can also be connected in parallel with the relay 1 as shown in FIG. In this case, in order to adjust the current flowing through the light emitting diode 10a, it is necessary to connect a resistor izf in series with the diode.

〔Effect of the invention〕

As explained above, 1. According to the interlock detection circuit of the copying machine of the present invention, the interlock circuit and the power supply of the control system are separated, and the turning on and release of the power is controlled by a photocoupler activated by the operation of the interlock switch. Because I did it like that.

The power supply voltage of the interlock circuit can be set arbitrarily, and when the power supply voltage on the interlock circuit side is increased, noise resistance can be improved and more reliable operation can be guaranteed.

[Brief explanation of drawings]

Fig. 1 is a circuit diagram of a conventional copying machine interface and detection circuit, Fig. 2 is a circuit diagram of an embodiment of the present invention, and Fig. 3 is a circuit diagram of an embodiment of the present invention.
FIG. 3 is a circuit diagram showing a modification of the embodiment shown in the figure. Explanation of symbols l...Relay, 2...Motor, 3.4...Interlock switch, 7...Inverter, 1°...Photocoupler, 10m...Light emitting diode 10b...
・Phototransistor, 11.12...Resistance. Patent applicant: Fuji Zero, representative of Kusu Co., Ltd. Patent attorney: Shin Matsuhara 2 Patent attorney: Seishunma Muraki Patent attorney: Taira 1) Tadashi Shiima Patent attorney: Atsushi Ueshima - Patent attorney: Suzuki Ceramics Figure 1, Figure 2

Claims (1)

[Scope of Claims] A copying machine including an interlock switch that operates a power supply unit that supplies power to a drive system and a control system by being activated in response to opening and closing of a door of the copying machine, the power supply unit comprising: is characterized by comprising a light-emitting section that operates based on the on-state of the interlock switch to supply the first power source, and a light-receiving section that operates based on the operation of the light-emitting section and supplies the second power source. Copy machine interface detection circuit.