JPH07219069A - Lighting device - Google Patents

Abstract

PURPOSE:To stabilize the quantity of light of a fluorescent lamp and improve the light emission efficiency by connecting a heat radiation member to outside the effective light quantity area of the fluorescent lamp through a cooling member which is close to the fluorescent lamp tube, and then forming the coldest part outside the effective light area of the fluorescent lamp. CONSTITUTION:Rubber elastic bodies, e.g. a highly heat-conductive silicone rubber is used as cooling members 6a and 6b which are high in heat conductivity and made of elastic bodies. The cooling members 6a and 6b are fitted closely outside the effective light quantity area of the fluorescent lamp tube. The heat radiation member 8 made of a material which is good in heat radiation efficiency such as an aluminum plate is connected to the fluorescent lamp 2 thorugh the cooling members 6a and 6b. Further, the heat radiation member 8 is supported on a mirror base 10 with pins 9a and 9b slidably as shown by am arrow (a) and pressed against in the left direction of (a) by leaf springs 4a and 4b. Further, contact surfaces for the cooling members 6 are formed at both end parts of the heat radiation member 8 and come into contact under a specific abutting pressure with the energizing forces of the leaf springs.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluorescent light source used for illuminating an original document of a copying machine or the like.

[0002]

2. Description of the Related Art Conventionally, in a copying machine using a fluorescent lamp as an exposure light source, the light quantity of the fluorescent lamp is generally determined by the vapor pressure of mercury sealed inside the fluorescent lamp and the emission characteristics of the fluorescent film formed on the inner wall of the tube. Since the mercury vapor pressure and the light emission characteristics of the fluorescent film depend on the tube wall temperature of the fluorescent lamp, the amount of light changes depending on the temperature of the fluorescent tube wall.

Therefore, in order to adjust the tube wall temperature to a temperature at which the amount of light can be obtained most efficiently, heating means such as a heater and cooling means such as a heat sink and a fan are arranged so that the tube wall temperature becomes a predetermined value. A method of controlling is adopted.

In addition, excess mercury particles gather in the "coolest part" of the fluorescent lamp tube where the temperature is the lowest, and if these excess mercury particles remain in the effective light quantity region, the light quantity distribution becomes nonuniform. The effective light amount region is kept at a predetermined temperature or higher by a heating means such as a heater, and at the same time, the coldest portion is formed outside the effective light amount region by a cooling means such as a heat sink or a fan.

[0005]

However, in the above-mentioned conventional example, since the heat sink and the fan are used as the cooling means for forming the coldest part outside the effective light amount region, the cost of the cooling member is high. Also, there is a problem in terms of assembly because it is difficult to join the heat transfer from the fluorescent lamp to the heat sink.

In order to solve the above-mentioned problems, it is an object of the present invention to provide an illuminating device capable of forming the coldest portion outside the effective light amount region of a fluorescent lamp by a simple means.

[0007]

In order to achieve the above object, the present invention provides a heat radiating member outside the effective light amount region of the fluorescent lamp through a cooling member in close contact with the fluorescent lamp tube wall.

The cooling member is made of an elastic body having high thermal conductivity,
Due to its elastic force, it is in close contact with the wall of the fluorescent lamp.

The elastic body is preferably a rubber-like elastic body. The cooling member may be a ring-shaped member or may be in close contact with the entire circumference of the fluorescent lamp tube wall.

Further, the cooling member may be attached to the end side of the filament position in the fluorescent lamp.

The present invention is also used as a document illuminating device of an image forming apparatus.

In this case, the original illuminating device may be attached to a movable mirror base that illuminates and scans the original surface, and the mirror base may serve as a heat dissipation member.

[0013]

When the fluorescent lamp is turned on, the temperature of the fluorescent lamp tube wall rises, but the heat of the portion where the cooling member is in close contact is radiated into the air through the cooling member and the heat radiating member. As a result, the portion where the cooling member is in close contact is cooled, and the "coolest portion" having the lowest temperature in the fluorescent lamp tube is formed outside the effective light amount region of the fluorescent lamp. Therefore, excess mercury particles in the fluorescent lamp collect outside the effective light amount region, and the light amount distribution in the effective light amount region can be stabilized.

If the cooling member is made of an elastic body having a high thermal conductivity, the elastic force of the cooling member ensures that the cooling member closely contacts the fluorescent lamp tube wall.

If the cooling member is a rubber-like elastic body,
Adheres tightly to the wall of the fluorescent lamp tube without gaps, improving cooling efficiency.

If the cooling member is formed into a ring shape and is brought into close contact with the entire circumference, the contact area is increased and the cooling efficiency is further improved.

The end side of the filament position inside the fluorescent lamp has a lower temperature in the fluorescent lamp, and it is easy to form the coldest part.

If it is used as a document illuminating device of an image forming apparatus, uniform and stable illumination can be obtained without using complicated cooling means such as a heat sink and a fan.

If it is mounted on a movable mirror stand, the heat radiation effect is enhanced by the wind during movement.

If the mirror base itself is used as a heat dissipation member, the structure will be further simplified.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to illustrated embodiments.

FIG. 1 shows a mirror stand for illuminating and scanning a document surface of an image forming apparatus as an illuminating apparatus according to an embodiment of the present invention.

In FIG. 1, reference numeral 1 denotes the entire scanning mirror base, on which the fluorescent lamp 2 and the sockets 3a for supplying power to the fluorescent lamp 2, which are inserted into the electrodes at both ends of the fluorescent lamp 2,
3b and a reflection mirror 5 for reflecting the light emitted from the fluorescent lamp 2 to the document surface.

6a and 6b are cooling members having a high thermal conductivity and made of an elastic body. In this embodiment, a rubber-like elastic body, for example, a high thermal conductive silicone rubber is used. The cooling members 6a and 6b are attached in close contact with each other outside the effective light amount region of the fluorescent lamp. Reference numeral 8 denotes a heat dissipation member made of a material having a high heat dissipation efficiency such as an aluminum plate, which is connected to the fluorescent lamp 2 through the cooling members 6a and 6b. The heat dissipating member 8 is slidably supported on the mirror base 10 by the pins 9a and 9b in the direction of arrow a in the figure, and is pressed against the left side of FIG. 1 by the leaf springs 4a and 4b.

FIG. 2 is a detailed view of the end portion of the scanning mirror base 1. The cooling member 6 has a ring shape in which the outer peripheral upper and lower surfaces are cut to reduce the size in the height direction, and the inner diameter of the fluorescent member 2 is reduced.
By setting the diameter slightly smaller than the outer diameter, the inner peripheral surface is in close contact with the outer wall surface of the fluorescent lamp 2 due to its elastic force.

By disposing the cooling member 6 on the end side with respect to the filament 4 of the fluorescent lamp 2, the temperature is lower in the fluorescent lamp 2 and the cooling member 6 is installed at a place easy to be the coldest part. .

A contact surface with the cooling member 6 is formed at both ends 8a of the heat dissipation member 8, and a leaf spring (not shown in FIG. 2) is formed.
The contact force is a predetermined contact pressure due to the urging force of. Also in this case, the rubber-like elastic force of the cooling member 6 enhances the adhesion of the contact surface. Here, by disposing the heat dissipation member 8 so as to be a wall with respect to the effective light amount region of the fluorescent lamp 2, when the scanning mirror base 1 scans and moves in the direction A of FIG. By receiving it efficiently, the heat radiation effect can be improved.

When the fluorescent lamp 2 is in the operating state, the temperature of the tube wall of the fluorescent lamp 2 rises due to the heat generation of the filament 4.
At this time, the pipe wall portion on which the cooling member 6 is installed is cooled by the cooling member 6.
Since the heat escapes to the heat radiating member 8 via the pipe, the temperature of the pipe wall is always kept lower than the other portions, and the coldest portion is formed.

A second embodiment is shown in FIG. The cooling member 16 is provided with a square hole 17a into which the heat dissipation member 8 is inserted, and the width b of the square hole 17a is set to be slightly smaller than the thickness of the heat dissipation member 8 so that when the heat dissipation member 8 is inserted. Due to the elasticity of the cooling member 16, the surface of the heat dissipation member 8 and the cooling member 16 surely come into close contact with each other. As a result, sufficient thermal conductivity can be obtained even with the configuration without the leaf spring 9 shown in the first embodiment, and the coldest portion similar to the first embodiment is formed.

Example 3 is shown in FIG.

In this embodiment, the cooling member 6 is directly brought into contact with the mirror base 10 at its portion 11 in the drawing by virtue of its elasticity so that the mirror base 10 can be used as the heat radiating member 8. The coldest part is formed.

Although various shapes have been shown as the cooling member and the heat radiating member, the shapes are not limited to these examples, and they are not necessarily arranged at both ends.

However, by using a symmetrical shape for the cooling member, the same member can be used at both ends, and a balanced structure can be achieved in terms of temperature characteristics.

[0034]

The present invention has a simple structure in which a heat dissipation member is connected to the outside of the effective light amount region of a fluorescent lamp through a cooling member in close contact with the fluorescent lamp tube, and a heat sink, a fan or the like is used as in the prior art. Therefore, the coldest part can be formed outside the effective light amount region of the fluorescent lamp, and the fluorescent light amount can be stabilized and the luminous efficiency can be improved.

If the cooling member is made of an elastic body having a high thermal conductivity, the elastic force of the cooling member ensures that the cooling member is in close contact with the fluorescent lamp tube wall, resulting in good cooling efficiency.

If the cooling member is a rubber-like elastic body,
The fluorescent lamp tube can be closely attached to the wall without any gap, and the cooling efficiency can be improved.

If the cooling member is formed into a ring shape and is brought into close contact with the entire circumference, the contact area is increased and the cooling efficiency is further enhanced.

If the cooling member is provided on the end side of the filament position in the fluorescent lamp, it is easy to make the coldest part.

When used as a document illuminating device of the image forming apparatus, uniform and stable illumination light can be obtained without using complicated cooling means such as a heat sink and fan, and thus stable image quality can be obtained.

If it is mounted on a movable mirror stand, the heat radiation effect is enhanced by the wind during movement.

If the mirror base itself is used as a heat dissipation member, the structure can be further simplified.

[Brief description of drawings]

FIG. 1 is an overall view of a scanning mirror base embodying the present invention.

FIG. 2 is an enlarged view of a main part of FIG.

FIG. 3 is an enlarged view of a main part of the second embodiment.

FIG. 4 is an enlarged view of a main part of the third embodiment.

[Explanation of symbols]

 1 Scanning mirror stand (illumination device) 2 Fluorescent lamps 6, 6a, 6b Cooling member 8 Heat dissipation member

Claims (8)

[Claims] 1. An illuminating device characterized in that a heat dissipation member is provided outside the effective light quantity region of a fluorescent lamp via a cooling member in close contact with the fluorescent lamp tube wall. 2. The cooling member is made of an elastic body having high thermal conductivity,
2. The elastic force closely contacts the wall of the fluorescent lamp.
The lighting device according to. 3. The lighting device according to claim 2, wherein the elastic body is a rubber-like elastic body. 4. The cooling member is a ring-shaped member and is in close contact with the entire circumference of the fluorescent lamp tube wall.
The lighting device according to. 5. The lighting device according to claim 1, wherein the cooling member is attached to the end side of the filament position in the fluorescent lamp. 6. The illumination device according to claim 1, which is used as a document illumination device of an image forming apparatus. 7. The illuminating device according to claim 6, wherein the document illuminating device is attached to a movable mirror table that illuminates and scans the document surface. 8. The lighting device according to claim 7, wherein the mirror base is used as a heat dissipation member.