JPH0589973A - Lamp lighting device - Google Patents

Abstract

PURPOSE:To provide a lamp lighting device which turns off a lamp through simple constitution and outputs an abnormality signal if lighting of the lamp is continued for a time linger than a predetermined time. CONSTITUTION:In the normal condition, a Zener diode ZD2 is turned on and current is fed to the base of a transistor Q1 and a relay coil RyL closes a relay contact RyS. The alternating current of a commercial AC power source E is power-converted by a chopper circuit 2 and lights a lamp L. When the lamp L is lighted a Zener diode ZD1 is turned on and the photocoupler emission side PTC of the diode detects emission of light. When the lighted state of the lamp L is continued for a long time, a timer circuit 5 sends an output to turn on a thyristor Th; the Zener diode ZD2 is turned off and current flowing through the relay coil RyL is cut off; the relay contact RyS is opened and the chopper circuit 2 stops output to turn off the lamp L; the thyristor Th is turned on so that a transistor Q2 is turned on to output an abnormality signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lamp lighting device which stops when a lamp is kept on for a predetermined time or longer.

[0002]

2. Description of the Related Art Conventionally, in the case of a lamp used in, for example, a copying machine, it is known that the lamp is extinguished because the lamp is overheated when it is kept on for a long time.

[0003]

However, in the case of the conventional configuration, a means for turning off the lamp when the lamp is kept on for a long time, and an abnormal signal is output to notify that the lamp has become abnormal. Since it is separate from the means for doing so, there is a problem that the circuit becomes complicated.

The present invention has been made in view of the above problems, and provides a lamp lighting device that outputs a fault signal while stopping the lamp when the lamp continues to be lit for a predetermined time or more with a simple structure. To aim.

[0005]

A lamp lighting device of the present invention is a lamp lighting means for lighting a lamp, an output stopping means for stopping an output of the lamp lighting means, and a lamp lighting detection for detecting lighting of the lamp. Means, timer means for measuring time when the lamp lighting detection means detects lighting of the lamp, switching means for operating the output stopping means when a predetermined time is measured by the timer means, and the switching means. Is provided with an abnormal signal output means for outputting an abnormal signal when the output stopping means is operated.

[0006]

In the lamp lighting device of the present invention, when the lighting of the lamp is detected by the lamp lighting detection means, the timer means counts the time, and when the timer means measures a predetermined time, the switching means operates the output stopping means. At the same time, since the abnormal signal output means outputs the abnormal signal, the lamp is stopped and the abnormal signal is output with a simple configuration when the lamp continues to be lit for a predetermined time or longer.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a lamp lighting device of the present invention will be described below with reference to the drawings of a lighting device for an exposure halogen lamp for a copying machine.

In FIG. 1, E is a commercial AC power supply, and this commercial AC power supply E is connected to a rectifying / smoothing circuit 1 via a normally open relay contact RyS as an output stopping means. A chopper circuit 2 as a lamp lighting means is connected to an output terminal of the rectifying / smoothing circuit 1.

The chopper circuit 2 is composed of a field effect transistor FET and a freewheeling diode D1, and a halogen lamp L is provided on the output terminal side of the chopper circuit 2.
Are connected. A series circuit of a diode D2 and a capacitor C1 is connected in parallel to the halogen lamp L, and a resistor R1 is connected in parallel to the capacitor C1.
And PTC and Zener diode ZD1 on the photocoupler side
The lamp lighting detection means 3 is connected. Further, a control circuit 4 for controlling the chopper is connected to the gate of the field effect transistor FET.

E1 is a DC power supply, and a relay coil for driving a relay contact RyS is provided between both terminals of the DC power supply E1.
RyL and the collector / emitter of transistor Q1 are connected. The Zener diode ZD2 is connected to the base of the transistor Q1.
ZD2 is connected to the positive electrode of the DC power supply E1 via the resistor R2. Furthermore, the Zener diode ZD2 is connected to the thyristor Th as a switching means,
Th is connected to the base of a transistor Q2 as an abnormal signal output means, and a resistor R3 is connected between the base and emitter of this transistor Q2.

The gate of this thyristor Th is
A resistor R4 and a capacitor C2 are connected to each other, and via a resistor R5, to a timer circuit 5 as a timer means. The timer circuit 5 has a phototransistor light emitting side PTC and a phototransistor PTr photocoupled. There is.

Next, the operation of the above embodiment will be described.

At normal times, the direct current from the direct current power source E1 passes through the resistor R2 and the Zener diode ZD2 to form a transistor.
Since current is supplied to the base of Q1, relay coil RyL
A current flows through the relay contact RyS and the relay contact RyS is closed.

The AC of the commercial AC power source E is rectified and smoothed by the rectifying and smoothing circuit 1 and converted into electric power by the chopper circuit 2 to turn on the lamp L. When the lamp L is lit in this way, the voltage of the capacitor C1 rises, the Zener diode ZD1 turns on, the photocoupler light emitting side PTC emits light, and the phototransistor PTr of the timer circuit 5 turns on.

After that, when the state in which the lamp L is lit becomes longer than the set time, the timer circuit 5 outputs and the gate of the thyristor Th is triggered to turn on the thyristor Th. And Zener diode ZD2
Is turned off to turn off the current flowing through the relay coil RyL, the relay contact RyS is opened, the chopper circuit 2 stops the output, and the lamp L is turned off. On the other hand, when the thyristor Th turns on, the transistor Q2 turns on and outputs an abnormal signal.

[0016]

According to the lamp lighting device of the present invention, when the lighting of the lamp is detected by the lamp lighting detecting means, the timer means counts the time, and when the timer means measures a predetermined time, the switching means stops the output. In addition to operating the means, the abnormal signal output means outputs an abnormal signal,
With a simple configuration, the lamp can be stopped when it continues to light for a predetermined time or longer, and an abnormal signal can be output.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of a lamp lighting device of the present invention.

[Explanation of symbols]

 2 Chopper circuit as lamp lighting means 3 Lamp lighting detecting means 5 Timer circuit as timer means L Halogen lamp Q2 Transistor as abnormal signal output means RyS Relay contact as output stopping means Th Thyristor as switching means

Claims (1)

[Claims] 1. A lamp lighting means for lighting a lamp, an output stopping means for stopping output of the lamp lighting means, a lamp lighting detecting means for detecting lighting of the lamp, and a lamp lighting detecting means for turning on the lamp. Timer means for counting the time when lighting is detected, switching means for operating the output stopping means when a predetermined time is measured by the timer means, and an abnormal signal when the switching means operates the output stopping means A lamp lighting device, comprising: an abnormal signal output means for outputting.