JPS60227396A - Device for firing discharge lamp - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] 〔Technical field〕 This invention relates to a waste paper lamp lighting device.

[Background technology]

When lighting a fluorescent lamp, the filament must be kept within a certain optimum temperature range; if it deviates from this range, the electrode filament becomes stranded, causing the electrode material to wear out and scatter, causing blackening of the inner surface of the tube wall. becomes.

Generally, when starting a fluorescent tube, in order to ensure that the filament reaches the above-mentioned optimum temperature, a filament preheating current must be applied to the filament as shown in Figure 2 or Figure 3 to heat the filament to the appropriate temperature before starting. No. Therefore, there is a problem in that the lamp cannot be turned on immediately after the power is turned on, and a waiting time (to-t operation) is required. In addition, in FIG. 2 and FIG. 3, to is the preheating start time, and t is the lamp lighting time.

By the way, in many cases where the lamp is used in copying machines, facsimile machines, etc., it is desirable that the above-mentioned waiting time is short, but on the other hand, the lamp is not turned on immediately after the waiting time ends, and the time until the lamp turns on (standby time) ranges from several seconds to several tens of seconds. It can last up to minutes. Furthermore, as shown in FIG. 4, even after the lamp is turned off, the filament is always preheated (standby), and when a lamp lighting signal is received, it is often necessary to turn on the filament instantaneously.

In such use, the preheating current is usually set to a current value that does not cause blackening even if the product is continuously preheated, and the waiting time (1o-1) inevitably becomes longer. .

Specific filament preheating methods for lighting in the sequence shown in FIG. 4 include an AC preheating method and a DC preheating method.

Figure 5 shows an AC preheating discharge lamp lighting circuit.
is a fluorescent lamp, IV shield inverter, FT type is a filament transformer, and C type is an oscillation transformer.

Fig. 6 (2) shows the change in filament temperature, Fig. 6 0 shows the change in filament current and filament voltage V, and IF and VF are set to levels that do not cause blackening even if constantly preheated. K indicates the appropriate filament temperature.

Figure 7 shows a DC preheating discharge lamp lighting circuit.

LA is a fluorescent lamp, IV is an inverter, CH is a choke coil, CO is a capacitor, OK is an oscillation transformer, B
y Preheating switch, shi, is the lighting switch. Figure 8 (2) shows the change in filament temperature; Figure 8 (2) shows the change in filament temperature;
81 is the filament current I, and the filament voltage ■
, and its level is set in the same way as in the AC preheating method described above.

[Purpose of the invention]

An object of the present invention is to provide a discharge lamp lighting device that can shorten waiting time without adversely affecting lamp life.

[Disclosure of the invention]

The discharge lamp lighting device of the present invention rapidly preheats the filament by passing a large current (rapid preheating current) through the filament for a certain period of time at the time of initial startup or until the filament temperature reaches a predetermined value. The present invention is characterized in that the preheating current value is promptly returned to a steady value after the heating is completed.

With this configuration, it is possible to shorten the waiting time until the filament reaches the proper braid.

Moreover, the filament temperature does not become abnormally high during the standby time for instantaneous lighting of the lamp, and the lamp life is not adversely affected and there is no limit to the standby time.

FIG. 9 shows this. Q in FIG. 9 (5) shows the conventional filament temperature change curve, Q' shows the filament temperature change curve according to the present invention, and IP"F in FIG.
shows the conventional filament current and filament voltage change curves, and I,', VF' shows the filament current and filament voltage change curves according to the present invention. t is the preheating start time, t is the time when the filament reaches the appropriate temperature in the conventional method, and t is the time when the filament reaches the appropriate temperature in the present invention.

Hereinafter, specific embodiments of the present invention will be described based on the drawings.

A first embodiment of this invention will be described based on FIGS. 1 and 10. In this discharge lamp lighting device, power is supplied from a DC power source to an inverter (Iv) via a lighting switch SW2, and high frequency power is supplied from an oscillation transformer (g) to a fluorescent lamp LA.

On the other hand, for preheating the fluorescent lamp LA, power is supplied from the AC power supply to the preheating transformer FT2 via the preheating switch Sw□, and the secondary output of this preheating transformer is sent to the filament F, F,
This is done by adding .

A more detailed explanation will be given below with reference to FIG. 1θ.

Time t. When the preheating switch 5Wle is turned on, power is supplied from the AC power supply to the preheating transformer, but at this time, the primary winding N2 is normally closed and short-circuited by the V-contact ry2 (the voltage is applied only to the primary winding N). Because of this, the primary and secondary turns ratio of the preheating transformer FvI+2 is large, and the filament voltage vF applied to the filament F is large.
is high, and therefore a large amount of filament current I2 flows. As a result, the temperature of filaments F and F2 rises rapidly. Note that since the filament current IF is decreasing, this is due to an increase in resistance due to the rise in temperature, and eventually it stabilizes at a value corresponding to the filament voltage , and the filament) f
f1 degrees will also become stable.

On the other hand, when the preheating switch 3v1 is turned on, the rectifier DB
The rectified voltage charges the capacitor C through the resistor R, and when the charging voltage of the capacitor C exceeds a predetermined value at time t', which is a certain period of time after the preheating switch + SW is turned on, the switch element 8BS is activated. It turns on and makes the thyristor SCR conductive via the transformer TR. As a result, the relay Ri is energized, the normally closed relay contact ry is opened, the primary/secondary winding ratio of the preheating transformer FWI'2 is decreased, the filament voltage (2) is decreased, and the filament current I2 is at the steady value. It will become stable. Also, at this time, the normally open relay contact r connected in parallel to thyristor 8CR
The Y is closed and becomes a self-holding state, and the filaments F and F2 of the fluorescent lamp LA are in a steady preheating state, and after this, the fluorescent lamp can be turned on instantaneously at any time.

For example, when the lighting switch 5vr2 is turned on at time t, power supply to the inverter 2 is started, the fluorescent lamp LA is lit, and the lamp current ILA flows.

As a result of this configuration, it is possible to shorten the waiting time at the time of initial startup, and to suppress the blackening phenomenon of the fluorescent lamp LA during standby.

A second embodiment of the invention will be described based on FIGS. 11 and 12. In this discharge lamp lighting device, when the preheating switch Sw is turned on, the voltage divided by the resistors R3 to R6 is applied to the positive input terminal of the operational amplifier OP, and the operational amplifier OP makes the transistor T r F almost conductive. west,
The filament voltage of the fluorescent lamp LA, the transistor Tr from the DC power supply to F2, the resistor R1 and the winding N1 of the oscillation transformer C8. A large preheating current flows through N2,
Fifmen) F,, F2 are rapidly preheated. Furthermore, when the preheating switch Sw is turned on, charging of the capacitor CT is started via the resistors R and r, and when a certain period of time elapses after the preheating switch Sw is turned on, the voltage of the capacitor CT changes to the resistor R. R engineering, exceeds the midpoint voltage, operational amplifier OP2
The output of transistor 'l'r2. changes from H to L, and the output of transistor 'l'r2.
When Trl goes out, the resistor R6 is shorted, and the positive input of the operational amplifier OP decreases.
The operational amplifier OP shielding transistor TrF is set to have a predetermined impedance, and the preheating voltage (2) flowing through the filaments F is lowered to a steady value to bring the preheating current (2) to a steady value, thereby transitioning to a steady preheating state. the result.

The fluorescent lamp LA can be turned on instantly at any time.

When the lighting switch Sw2 is turned on, the transistor Tr
4 is turned on and power supply to inverter V2 is started, using the inverter output. The fluorescent lamp LA is turned on via the oscillation transformer Or2, and a lamp current ILA flows.

At the same time, the transistor 'l'r3 is turned on, shorting the resistors R4 to R6, and increasing the calculation m1o.
The positive input of p□ is set to zero, and the transistor T ry is immediately turned off to cut off the preheating current.

After that, when the lighting switch SW2 is turned off, the steady preheating state is returned again.

In addition, R, R2, R7 to R engineering 0. R-engineer. ~R is a resistor, D is a diode, D is a diode, CO is a capacitor, and CH is a choke coil.

FIG. 12 is a diagram showing this, where to is the time when the preheating switch Sw is turned on, and t' is the preheating voltage v, d.
(The time when the lighting switch Sw2 drops to the steady value, 18.1., 16 is the time when the lighting switch Sw2 is turned on, and 13.15 is the time when the lighting switch 8vr2 is turned off.
TF indicates a filament heat generation area due to rapid preheating, TF indicates a filament heat generation area due to steady preheating, and TL indicates a filament heat generation area due to lamp current.

The effects of this embodiment are similar to those of the first embodiment.

A third embodiment of the invention will be described based on FIG. 13. In this discharge lamp lighting device, when the preheating switch 8W is turned on, the voltage divided by the resistors R3 to R6 is applied to the operational amplifier O.
The operational amplifier IN OF□ makes the transistor TrF almost conductive, and the fluorescent lamp LA
filament F, winding N of transistor TrF, resistor RF and oscillation transformer σ from DC power supply to F2,
A large preheating current flows through the filament) F
1, F2 is rapidly preheated.

In addition, the operational amplifier OP detects a rise in the temperature of the filament temperature F2 as a decrease in the voltage drop of the resistor RF by comparing the voltage drop of the resistor RF with the midpoint voltage of the resistors R12 and R. (because the resistance value decreases as the filament temperature rises), and when the filament temperature becomes higher than a predetermined value, that is, the resistance RF
When the voltage drop becomes lower than a predetermined value, the output changes from H to L, transistor Tr21 turns on, resistor R6 is shorted, and the positive input of operational amplifier oP becomes Therefore, the operational amplifier OP shunting transistor TrF is set to have a predetermined impedance, and the preheating voltage flowing to F and F2 is reduced.
, is lowered to a steady value, the preheating current is set to a steady value, and the state is shifted to a steady preheating state. As a result, the fluorescent lamp LA can be turned on instantaneously at any time.

When the lighting switch Swa is turned on, the transistor Tr
4 is turned on, power supply to the inverter IV is started, and the inverter output lights up the fluorescent lamp LA via the oscillation transformer 0T2, and the lamp current ILA flows. At the same time, the transistor Tr is turned on to short-circuit the resistors R4 to R6, the positive input of the operational amplifier OP becomes zero, and the transistor Tr is cut off.
Cut off preheating current.

R□, R8, R7~R work 0. R engineering, ~R engineering. is resistance,
C is a capacitor and D is a diode.

This embodiment also has the same effects as the previous embodiment.

In addition, the relationship between lamp lighting and preheating may be any one of 9 lighting core non-continuous lighting core thermal insulation, and does not depend on the type of power source (direct current, alternating current (including high frequency and pulse wave)).
Can be applied to a wide range of applications.

〔Effect of the invention〕

According to the discharge lamp lighting device of the present invention, the waiting time at the time of initial startup can be shortened, and the blackening phenomenon during standby can be suppressed.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of a first embodiment of the invention, FIG.
3 and 4 are timing diagrams for explaining the conventional preheating method, FIG. 5 is a circuit of an AC preheating method discharge lamp lighting device, and FIG. 6 (3) is a characteristic diagram of the filament temperature.
FIG. 6S) is a characteristic diagram of the filament current IF and filament voltage ■, FIG. 7 is a circuit diagram of a DC preheating discharge lamp lighting device, and FIG. 8(2) is a characteristic diagram of the filament temperature. Fig. 8 (81 is also a characteristic diagram of the filament current ■F and filament voltage vF, Fig. 9 (to), [Yes]
10 is a characteristic diagram of the lamp current, filament current, filament voltage and filament temperature in the embodiment of FIG. 1, and FIG.
The figure shows a circuit diagram of a second embodiment of the invention, FIG. 12 shows a characteristic diagram of the lamp current, filament current, filament voltage, and filament temperature, and FIG. 13 shows a circuit diagram of a third embodiment of the invention. be. LA...Lamp, F work, F2-...Filament,
swo...preheating switch, SW2...lighting switch, PI', -...preheating) lance, R...resistance, c.
...Capacitor, 8BS...Switch element, SCR
...Thyristor, Ry...Relay, Try...
) Runsistor, Qp□, op2... operational amplifier,
RT...Resistor, C0...Capacitor tOlltOll Fig. 2 Fig. 3 Fig. 4 Fig. 5 tOlltOll (A) (B) Fig. 6 Fig. 7 tOlltOll (A) (B) Fig. 11 Fig. 12

Claims (1)

[Scope of Claims] (1) A discharge lamp, a current switching type preheating circuit that supplies a rapid preheating current to a filament of the discharge lamp in response to turning on a preheating switch, and a current switching type preheating circuit that supplies a rapid preheating current to a filament of the discharge lamp in response to turning on a preheating switch, and a preheating circuit that supplies a rapid preheating current to a filament of the discharge lamp in response to turning on a preheating switch; and a preheating current switching control means for switching a filament preheating current that the preheating circuit supplies to the filament of the discharge lamp to a steady value when the preheating circuit has a filament of the discharge lamp. 2) The discharge lamp lighting device according to claim 1, wherein the preheating current switching control means is a timer circuit, and the predetermined condition is that a predetermined period of time elapses after the preheating switch is turned on. (3) The preheating current switching control means is a resistance value change detection circuit that detects the temperature of the filament of the discharge lamp as a change in its resistance value, and the certain condition means that the resistance value of the filament is equal to or higher than a predetermined value. A discharge lamp lighting device according to claim (1).