JPS5940494A - Device for firing fluorescent 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 The present invention relates to a fluorescent lamp lighting device for controlling tube wall temperature.

2. Description of the Related Art In image information processing devices such as copying machines and facsimile machines, fluorescent lamps are often used as devices for illuminating originals.

As an example of a fluorescent lamp is shown in FIG. 1, the previous value varies depending on the temperature of the tube wall (the temperature of its cold spot), and the value becomes most noisy at a predetermined temperature T1. Therefore, in some types of fluorescent lamp lighting devices, a heater is installed on the tube wall of the fluorescent lamp. We are making efforts.

FIG. 2 shows the main parts of such a conventional fluorescent lamp lighting device. The wall 1A of the fluorescent lamp 1 of this arrangement is covered with a planar lamp heater 5 except for the region 2 where light is emitted and the region 4 where the heat radiating member 3 is attached. A temperature sensor 6 for detecting the temperature of the tube wall is attached to the heat dissipation member 3.The temperature sensor 6 controls the lamp heater 5 in the state before the fluorescent lamp is turned on, and controls the temperature of the fluorescent lamp. The tube wall of the lamp 1 is preheated to the above-mentioned temperature]-1. After the fluorescent lamp 1 is turned on, when the tube wall temperature JJt rises from the temperature below 1, the ring tube 1 is rotated. U, the heat dissipation member 3 works to prevent the tube wall of the fluorescent lamp 1 from being cooled.
When the fluorescent lamp 1 is self-heated in the lit state, heat is radiated to keep the light amount constant.
There is.

By the way, in such a fluorescent lamp lighting device, copy l!
When Nm such as i becomes Δf, the temperature of the tube wall in the -C1 region 4 decreases first due to the heat dissipation action of the heat dissipation member 3. The mercury sealed in the fluorescent lamp 1 liquefies as the temperature decreases.
4 out of 4 areas! Attach to. The attached mercury vaporizes again when the copier or the like is powered on and the lamp heater 5 starts preheating, preparing for lighting. When lit, the amount of light from the fluorescent lamp 1 is determined by the vapor pressure of vaporized mercury.

Therefore, if the environmental temperature in which the fluorescent lamp lighting device is installed is normal, there will be no inconvenience in installing it separately, but if the temperature is low, mercury will adhere to the inner wall of area 4, causing problems. There is a delay in evaporation.

For this reason, the fluorescent lamp 1 is turned on before sufficient mercury vapor pressure is obtained, resulting in a slow rise in light output.

FIG. 3 shows the light output characteristics depending on the environmental temperature. The curve indicated by the dashed line 8 represents the characteristic when the lamp heater 5 is turned on for two and a half minutes at a room temperature of 20 degrees Celsius and then the lamp is turned on. In this case, the relative exposure ω is close to 100% immediately after the lighting starts, indicating an almost ideal light output. On the other hand, the curve shown by solid line 9 is 1
This shows the case where lighting is performed at an environmental temperature of 0 degrees Celsius. After lighting starts, the light output will decrease by several seconds.
The original is not sufficiently exposed. As a result, when a copying machine is used first thing in the morning in winter, for example, the first copy becomes dark, making it impossible to obtain good image quality.

In view of these circumstances, it is an object of the present invention to provide a fluorescent lamp lighting device that can provide stable light output even at low temperatures.

In the present invention, a plurality of heat dissipating members are installed on the tube wall of the fluorescent lamp!
A heater is built into these Gt.

Then, the heat radiating member corresponding to the portion of the tube wall that has the lowest temperature (coolest temperature) when the power is cut off is heated and covered by the heater only when the tube wall temperature is below a predetermined temperature. As a result, the mercury adhering to the tube wall portion to which the heat radiating member is attached quickly evaporates and covers the tube wall. At this time, the tube wall temperature is measured using the remaining heat radiating member. According to this fluorescent lamp lighting device, the coldest temperature is formed in the unheated portion of the tube wall to which the heat dissipation section H is attached, so lighting is performed when sufficient mercury vapor pressure is obtained. , the above objectives are achieved.

The present invention will now be described in detail with reference to the following embodiments.

FIG. 4 shows the appearance of a fluorescent lamp lighting device used in a copying machine. A region 2 from which the light of the fluorescent lamp 1 is emitted is placed opposite a reflector 11 which reflects a portion of the emitted light onto an upper platen (not shown). The other area 4 of the M wall 1A that is not covered by the lamp heater 5 has a first heat dissipating member 12 and a second heat dissipating member 12.
The heat dissipating members 13 are attached at slight intervals. A temperature sensor 14 or 15 is provided on the upper surface of each of these heat dissipating members 12,13.

Each heat dissipation member 12, 13 has a heater mounting hole 16 or 17 formed in the longitudinal direction of the fluorescent lamp 1, into which a heat dissipation member heater 18 having a shape not shown in FIG. 5 is inserted. Temperature sensor 14.15 and heat radiation member heater 1
The group 19 of 9117 connected to the fluorescent lamp 8 and the like is connected to a lighting controller 21, so that the temperature of the tube wall of the fluorescent lamp 1 during lighting is controlled. Both heat members 12
．． A cooling fan 7 is provided behind the fan 13 to cool them.

Figure 6 shows the electrical circuit of this fluorescent lamp lighting device. When the copying machine is powered on, the central control circuit 23 disposed within the lighting controller 21 determines which heat radiating member has the coolest temperature using a built-in non-volatile memory. Each time the power is turned on, a signal 110 I+ or '1'' is written into this nonvolatile memory alternately. When the signal 110 !1 is written, the first heat dissipating member 12 ( (Fig. 4) is considered to form the coldest temperature.In this case, the temperature sensor of the second heat dissipating member 13 (Fig. 4)→j'l 5 determines the coldest temperature.
Heating control of the heat radiating member 12 is performed. Signal +1 on the contrary
When 111 is written, the second heat dissipation member 13 is considered to be the one forming the coldest temperature, and the temperature sensor 4J'+4 of the first heat dissipation member is J, which means that the second heat dissipation member 13 is the one that forms the coldest temperature. Heating control of the unit 13 is performed.

When the power is turned on to the copying machine, a signal "'O" is written to the nonvolatile memory and returns to k. In this case, the second heat radiating member 13 was heated and controlled when the copying machine was last operated. That is, when the environmental temperature is low, the second heat radiating member 13 is heated when the copying machine is powered on. Since the power of the copying machine is turned off in this state, the first heat dissipating member 1 that has reached the coldest temperature
How much mercury is on the tube wall on the 2 side?

In this state, the central control circuit 23 uses the temperature sensor 15 to perform temperature control before lighting. Therefore, the temperature detection signal 24 outputted from the temperature sensor 15 is supplied to the temperature conversion circuit 25, and a temperature display signal 26 is created that represents the temperature of the tube wall portion to which the second heat dissipation member 13 is attached in terms of voltage. . The temperature display signal 26 is supplied to a sample and hold circuit 27, and sampled by a sambling instruction signal 28 supplied at a predetermined period from the central control circuit 23. Sampled and its value is held 1. , :Temperature display signal 2
9 is supplied to the comparison input terminal ■1 of both the first comparator 31 and the second comparator 32.

The first comparator 31 has a reference voltage 3 at its reference input terminal I2.
3 is input, and this is compared with the first set temperature.

Here, the first set temperature is the temperature 1 described above. It is desirable to set the first set temperature to 30 to 40 degrees Celsius. In this embodiment, the first set temperature T1 is set to 361℃ as shown in FIG. On the other hand, the second comparator 32 inputs a reference voltage 34 to its reference input terminal 12, thereby comparing it with the second set temperature '1-2'. Here, the second set temperature T2 is a temperature (20 to 301 m) which is normally lower than the first set temperature T1 and at which the tube wall of the fluorescent lamp 1 is maintained close to room temperature. In this embodiment, the second set temperature 12 is set to 24 degrees Celsius, as shown in FIG.

When the power to the copying machine is turned on, the ambient temperature is, for example, 10 degrees Celsius. In this case the first and second comparators 31.
32 outputs a heating control signal 35, 36 of 1-1 (high) level, indicating that the tube wall temperature is lower than the reference temperature. In this state, both the lamp heater power supply circuit 37 and the first heat radiating member heating rri source circuit 38 are turned on. When the lamp heater power supply circuit 37 is turned on, the lamp heater b is heated. Further, when the first heat dissipation member heating power supply circuit 3B is turned on, the heat dissipation member heater 18 in the first heat dissipation member 12 is heated. As a result, the tube wall coated with mercury is heated, and the mercury evaporates rapidly. In this state, the second heat radiating member 13 is not heated. The tube wall at the mounting position is air-cooled by the fins of the second heat radiating member 13. This tube wall section therefore forms the coldest temperature.

When the temperature of this tube wall portion of the second heat radiating member 13 rises to the second set temperature 1'2 (24 degrees Celsius), the heating control signal 36 changes to L (low) level, and the first Heat dissipation member 1
Heating of the heater 18 for heating the matured part in 2 is stopped. After this, the tube wall is heated only by the lamp heater 5. When the temperature of the tube wall portion rises to the first set temperature T+ (36 degrees Celsius), the heating control signal 35 also changes to L level. At the same time, the fluorescent lamp 1 becomes ready to start lighting. Further, when the heating control signal 35 is at the L level, the cooling fan power supply circuit 39 is turned on.
Cooling fan 7 is driven. This is to prevent the tube wall temperature from rising due to self-heating when the fluorescent lamp is turned on. By exclusive on/off control of the first heat radiating member heating power supply circuit 38 and the cooling fan power supply circuit 39, the tube wall temperature of the fluorescent lamp 1 is maintained in a range very close to the ideal temperature 1.

When the day's copying work is completed, the power to the copying machine is turned off. When the power is turned on the next morning, the contents of the nonvolatile meter in the central control circuit 23 are read out, and the inverted signal 1 is read out.
11 I+ is predicted. Therefore, the temperature of the fluorescent lamp lighting device is controlled by the temperature control υ14.

Therefore, the temperature detection signal 4 output from the temperature sensor 14
1 is m I! The temperature display signal 4 is supplied to the conversion circuit 42.
3 is created. The summing hold circuit 44 outputs a temperature display signal /16 sampled and held by the summing instruction signal 45. The temperature table unreliable @46 is supplied to the first J3 and the second comparator 47.48 and compared with the reference pressure 49.51, respectively.

The first comparator 47 compares the tube wall temperature with the first set temperature T1, and outputs a heating control signal 52 of 1 lvl when the tube wall temperature is lower. In this case, lamp heater power supply circuit 3
7 is turned on, and the lamp heater 5 is heated. Moreover, when the tube temperature is higher than 11 degrees, a heating control signal @52 at the lower level is output. At this time, the cooling fan power supply circuit 39 is turned on, and the cooling fan 7 performs forced air cooling. Further, when the cooling fan power supply circuit 39 is turned on for the first time, the fluorescent lamp 1 is ready to start lighting.

On the other hand, the second comparator 48 converts the stomach wall temperature to the second set temperature T.
Compare with 2. When the tube wall temperature is lower, the H level heating (III control signal 53 is output). In this case, the second heat dissipation member heating power supply circuit 54 is turned on, @
The heat radiating member heater 18 in the second heat radiating member 13 is heated.

FIG. 7 shows the light output characteristics of a fluorescent lamp lighting device that performs temperature control as described above. Solid line 5 in the diagram
The curve indicated by 5 represents a platform where the environmental temperature is 10 degrees Celsius,
The curve indicated by a dashed line 56 represents the case where the ring j1 degree is 20 degrees C. In this way, good light output can be obtained even when the environmental temperature is low.

As explained above, according to the present invention, good image recording or reading can be performed even if copying or other operations are started at a relatively long time after the power is turned on. You can make it even faster. In addition, since the remaining heat radiating members are used to form the coldest temperature while the heat radiating member is being heated, there is no restriction on the heating humidity of the heat radiating member, and the heating set temperature of the lamp heater section (first set temperature T + ) It becomes possible to make the heating set temperature (second set temperature -1-2>) of the heat dissipating member higher than that of the second set temperature. Therefore, the light output at low temperatures can be reliably stabilized.

[Brief explanation of the drawing]

Fig. 1 is a characteristic diagram illustrating the relationship between stomach wall temperature and relative light intensity of a fluorescent lamp, Fig. 2 is a perspective view showing fluorescent lamp J3 and its surrounding parts in a conventional fluorescent lamp lighting device, and Fig. 3 The figure is a characteristic diagram showing the light output characteristics of a fluorescent lamp in a conventional fluorescent lamp lighting device. Figures 4 to 7 are for explaining one embodiment of the present invention. FIG. 5 is a perspective view of the heat dissipation member heater; FIG. 6 is a block diagram showing the circuit configuration of the fluorescent lamp lighting device; FIG. 7 is a perspective view of the fluorescent lamp lighting device. It is a characteristic diagram showing f1 at the time of output. 1... Fluorescent lamp 2... Area for emitting light 4... Area for attaching heat dissipation member 5...
・Lamp heater 12.13...Heat radiation member 14
．． 15... Temperature sensor 1 no 18... Heat radiation section heater 23... Central control circuit 31.47... First comparator 32.48 ... Second comparator 37 ... Lamp heater power supply circuit 38 ...
・First heat dissipation member heating power supply circuit 54...Second heat dissipation member heating power supply circuit T1...First set temperature T2...Second set temperature application Human wealth 1 Representative of Xerox Co., Ltd.
Person Patent Attorney Ume Yu Yamauchi 1
.

Claims (1)

[Scope of Claims] A plurality of heat dissipating members each having a built-in heater and mounted at different locations on the tube wall of a fluorescent lamp, etc. A temperature pin 1 for measuring the temperature of the tube wall of the light lamp, a lamp heater for heating the tube wall that covers the tube wall portion of the fluorescent lamp, and a plurality of temperature ranges each time the fluorescent lamp is lit. temperature sensor selection means for selecting one or more temperature ranges from;
The tube wall temperature measured in the selected temperature range is compared with a first set temperature that is approximately equal to the imaginary tube wall temperature of the fluorescent lamp, and the lamp heater is energized and controlled to raise the tube wall temperature to this temperature. The first set temperature control means to be avoided and the temperature of the tube wall measured by the selected temperature lens are compared with the other second set humidity, and one of the heat radiating member heaters in the heat radiating member whose temperature is not being measured is Or installing a heat dissipating member that measures temperature by controlling multiple energizations.
and a second set temperature control means for raising the temperature to a set temperature of .