JPS5958792A - Firing circuit - 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 The present invention relates to a lighting circuit suitable for use in lamps that are frequently lit, such as in copying machines.

In general, lighting this type of lamp requires preheating, but in lighting devices that use a constant preheating method, if the preheating is sufficient, power consumption during lighting will increase and excessive preheating will occur, impairing the lamp life and preventing preheating. If the temperature is too low, the preheating time will become longer, or the lamp may start without sufficient preheating, which will shorten the life of the lamp. therefore,
In reality, we have taken these points into account and set it as a compromise.

The present invention has been made in view of these points, and aims to provide a lighting circuit that shortens the preheating time from inputting preheating input to starting lamp lighting, and does not shorten lamp life. be.

An embodiment of the present invention will be described based on the drawings. First, the inverter (2) which normally serves as the lighting circuit for the lamp (1).
is connected, and this inverter (2) is connected to the switch αn′f
r: has a terminal (3) connected to a lighting control circuit (not shown) via. In addition to such an inverter (2), a preheating circuit (5) having a terminal (4) to be connected to the lighting control circuit is provided. This preheating circuit (5)
has an inverter (6), and a transistor (7) is connected to this inverter (6). A control unit (8) is connected to the base of this transistor (7), and an operational amplifier (9) and a timer 〇〇 are connected in sequence to the terminal (4) side. This timer 〇() is configured If9 to open the switch (lυ) when set, and close the switch 0〕 upon time-up.

In such a measure, the rated preheating voltage Vp is applied to the lamp (1) by the preheating circuit (5), but in order to light it, first the terminal (4) is applied. Preheating input is applied and timer 00 is set to have a time width of t. Along with this timer 00 setting, the transistor (7) is controlled via the operational amplifier (9) and the control section (8), and a preheating voltage higher than the rated element thermal pressure Vp is generated. This preheating voltage is lowered to the rated preheating voltage Vp by the control section (8) during the time t set by the timer 00. During this time or immediately after that, the terminal (3
) receives a lighting command, and the inverter (2) operates to light the lamp (1).

Since preheating is performed in this way, the lamp life will not be shortened even if the preheating time is the shortest cycle.
Also, there is no negative effect on lamp life due to differences in preheating time during actual use.

The preheating voltage may be changed by controlling the input side or the output side of the preheating circuit (6), or in the case of a transistor inverter, the output of the inverter may be increased by controlling the base current of the transistor. Furthermore, as an example of voltage change, after a predetermined period of time has elapsed, the voltage may be lowered to 1 pressure,
It may be lowered in stages.

The present invention preheats the lamp to which the normal lighting circuit is connected as described above, by reducing the preheating voltage from the preheating voltage (11 higher than the rated preheating voltage within a certain period of time after the input is turned on) through the rated temperature voltage trench. Since the output is output from the circuit, the lamp life will not be shortened even if the preheating time is the shortest cycle, and there is no negative effect on the lamp life due to the difference in preheating time in the actual measurement. Since there is no need to apply pressure, it has the advantage of reducing power consumption loss.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, with FIG. 1 being a circuit diagram and FIG. 2 being a timing chart. 1...Lamp, 2...Inverter (normal lighting circuit)
, 5... Preheating circuit

Claims (1)

[Claims] The voltage application by the normal lighting circuit trap is stopped for a certain period of time from when the lighting command is issued to the lamp to which the normal lighting circuit is connected, and the preheating circuit starts at a voltage higher than the rated preheating voltage, and after a predetermined period of time has elapsed, the voltage application by the normal lighting circuit trap is stopped. This lighting circuit is characterized by a starting box inside and a lighting control circuit that outputs a preheating voltage that drops to the pressure.