JP2744389B2 - Document illumination device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an illuminating device for exposing an image using a fluorescent lamp, and more particularly to a document illuminating device used in an optical system of a device having a document reading section such as a copying machine, an image reader, and a facsimile. Things.

(Background Art) A fluorescent lamp is often used as a light source for exposing a document in a document illuminating device. Fluorescent lamps have filaments that emit thermoelectrons at both ends,
A region where a region not contributing to light emission enters the filament portion and a predetermined dimension from the filament portion (a so-called Faraday dark portion).
And the portion that actually contributes to the exposure (usually referred to as the effective emission length) is further narrowed in the region inside thereof, as compared with the entire length of the fluorescent lamp. For this reason, it is necessary to secure an extra length as the entire length of the fluorescent lamp, which is longer than the length required for exposing the original, and the depth direction of the entire apparatus becomes longer than necessary. A tube having a diameter of 16 [mm] was generally used.

In recent years, with the demand for further miniaturization of the apparatus, the use of fluorescent lamps having a smaller tube diameter, for example, a diameter of 10 [mm] or 8 [mm], has been put to practical use. An illumination device that can be arranged close to an exposure surface has been made possible. In order to reduce the above-mentioned depth, that is, the area of the non-light emitting portion in the longitudinal direction of the fluorescent lamp, a light emitting element having a longer effective light emitting length is used by shortening a so-called stem portion for supporting a filament. FIG. 5 shows an example of a lighting device using such a small-diameter fluorescent lamp as a background art of the present invention.

Document table glass 10 on which document 110 is placed
Below the box 3, a box-shaped frame 108 is provided. Inside the frame 108, there is provided an elongated small-diameter fluorescent lamp 101 and a reflecting member 102 arranged in parallel to the longitudinal direction of the fluorescent lamp 101. The fluorescent lamp 10 is located above the frame 108.
1, and an upper lid 107 covering the reflecting member 102 is provided in the entire longitudinal direction. Further, below the frame 108,
A photoconductor 105 is provided, and a frame 108 and the photoconductor 105 are provided.
Between them, a long imaging lens array 104 is arranged in parallel with the reflection member 102.

In the above configuration, the light beam emitted from the fluorescent lamp 101 is combined with the light beam reflected by the reflecting member 102 and the light beam directed directly to the original glass 103, and the illuminating position is exposed via the exposed portion (A in the figure). The light flux guided to P and reflected at the illumination position P is guided to the photoconductor 105 through the imaging lens 104.

[0006]

However, the above apparatus has the following drawbacks.

As described above, when the effective light emission length with respect to the entire length is increased by shortening the filament supporting member with a small-diameter fluorescent lamp, the heat in the fluorescent lamp during lighting turns on the light of the fluorescent lamp. You are going to cover the whole range.

FIG. 6 shows this state. FIG. 6 illustrates the area C on one side, taking into account that both sides of the fluorescent lamp are substantially symmetrical.

FIG. 6A is a top view and a side view of the vicinity of the fluorescent lamp of the illumination device shown in FIG.

FIG. 6B shows an area C in FIG. 6A.
Indicates the surface temperature of the portion of the fluorescent lamp 101 during lighting, and the surface temperature decreases toward the light emitting portion with the temperature due to the heat generation of the filament 201 as a peak. During lighting, due to the heat generated by the fluorescent lamp 101, the entire vicinity including the reflecting member 102 has a substantially similar temperature distribution tendency. Here, the fluorescent lamp 10 in the above-mentioned lighting device is used.
1 and its vicinity include a portion (area B) covered by the upper lid 107 and the reflecting member 102 in the longitudinal direction of the fluorescent lamp 101 and a portion (area A) opened as the exposure direction on the original irradiation side. I do.

In such a state, the temperature change of the surface of the fluorescent lamp in the area C when the fluorescent lamp 102 is turned off from on is as shown in FIG. At this time, the temperature drop immediately after the light is turned off differs between the area A and the area B.

That is, since the fluorescent lamp tube surface on the area A side faces the opening, the temperature immediately drops immediately after the lamp is turned off. However, the area B side has the reflection member 102 and the upper lid 1.
07, the temperature is less likely to drop than in the area A side.

Therefore, the mercury vaporized during the lighting tends to adhere as liquid particles to the inside of the tube wall on the area A side where the temperature change is large.

In such a state, when the fluorescent lamp is repeatedly blinked, the light necessary for exposing the original is directed to the area A, that is, the fluorescent light at both ends of the exposure area close to the filament on the original table illuminating side where the light necessary for exposing the original is directed toward the original table. Mercury adherence to the inner wall of the lamp increases, and the uniformity of the light amount distribution in the longitudinal direction on the drum surface is lost, resulting in a shortage of light on both sides.

[0015]

According to the present invention, there is provided a fluorescent lamp having an elongated tube wall for illuminating an original,
A reflecting member provided along the longitudinal direction of the fluorescent lamp and reflecting a part of light emitted radially from the fluorescent lamp, the reflecting member is made of metal; A heat coupling member that contacts both the fluorescent lamp tube wall and the reflective member is provided only on an end portion within the effective light emitting area of the lamp and only on a surface side of the fluorescent lamp tube wall facing the reflective member. It is characterized by having.

[0016]

FIG. 1 is a sectional view of a document illuminating apparatus according to a first embodiment of the present invention. In the figure, 101 is a fluorescent lamp, 102 is a reflecting member made of a metal having high thermal conductivity, for example, aluminum or the like, which has a heat radiation function. 103 is an original table glass on which an original 110 is placed, 104 is a short focus lens array, 105 is a photosensitive drum, 107 is an upper lid,
Reference numeral 08 denotes a frame for housing the lighting device, and reference numeral 120 denotes a thermal bonding material.

The thermal coupling member 120 is, for example, a silicone rubber having high thermal conductivity, which is located at a position different from the original illuminating side (A) of the fluorescent lamp, that is, here is substantially the same as the original platen glass of the fluorescent lamp. At a position on the opposite side, the space between the tube wall of the elongated fluorescent lamp 101 and the reflecting member 102 serving as a heat radiating member is filled and closely adhered to each other. That is, the heat coupling member has a function of transmitting the heat of the fluorescent lamp tube wall to the heat radiation member.

FIG. 2 is a perspective view mainly showing a fluorescent lamp which is a main part of FIG.

The position of the silicone rubber 120 in the longitudinal direction of the fluorescent lamp is near the left and right filament portions 131 and 132 of the elongated fluorescent lamp 101, which is within the effective light emission length of the fluorescent lamp.

As described above, in the present embodiment, the provision of the heat coupling member prevents the temperature of the tube wall from decreasing when the fluorescent lamp is turned off. Liquefied mercury can be prevented from adhering to the original table irradiation side of the fluorescent lamp.

The fluorescent lamp 101 is held at both ends by elastic support members 109 (only one side 109-1 is shown in FIG. 2). An elastic claw is provided on a part of the support member so as to engage with a wavy projection formed on a part 108-1 of the frame. That is, the support member 109
It is engaged with the frame 108 so as to be slidable in the direction of the arrow in FIG. Similarly, the rear side is configured to slide in the direction of the arrow b in the figure, and the position is regulated stepwise by the projections and the elastic claws.

With the above arrangement, the silicon rubber 120 is used to arrange the uniformity of the light amount on the photosensitive drum 105 in the longitudinal direction, and then the support members 109 are finely adjusted in the front-rear direction for both a and b. It is possible to adjust the distance away or close. At this time, since the silicone rubber 120 has elasticity, the silicone rubber 120 can follow stepwise position adjustment, and can maintain sufficient thermal coupling.

In particular, this configuration is effective against the inherent habit of manufacturing a fluorescent lamp.

That is, the step of applying a fluorescent substance on the inner surface of a fluorescent lamp employs a method in which a glass tube is placed in a vertical direction and a liquid fluorescent substance is poured from the upper part. It covers the entire inner wall of the pipe. Therefore, focusing on the thickness of the phosphor, the portion where the phosphor starts to flow tends to be thin, and the portion where the phosphor flows completely tends to be thick. In a conventional 16 mm diameter tube or the like, the inner diameter is large and the distance from the light emitting source to the document reflecting surface is sufficiently long, so that there is a slight inconvenience associated with manufacturing such a phosphor thickness. The tendency for uniformity was negligible,
In the case of a small-diameter fluorescent lamp having a diameter of 8 [mm] as in this embodiment and the distance to the document reflecting surface is reduced, the effect of uneven thickness of the fluorescent material appears, By the fine adjustment in the front-back direction as described above, the structure is such that the entire fluorescent lamp can be adjusted by being inclined from the parallel arrangement with respect to the reflecting member in the direction of correcting the non-uniformity of the application of the fluorescent material as a whole. It is effective.

Therefore, also in the above configuration, by forming the thermal coupling member with an elastic material, the thermal coupling member can sufficiently fill the space between the fluorescent lamp and the reflecting member, and the unevenness of the thickness of the fluorescent material is taken into consideration. The apparatus can prevent mercury from adhering to the platen illumination side.

FIG. 3 shows another embodiment of the present invention. The basic configuration is the same as that of the above-described embodiment, and only different parts will be described.

In the present embodiment, a heat conductive silicon sheet 121 as a heat coupling member is disposed by being bent between the fluorescent lamp 101 and the reflection member 102 which is a heat radiation member.

The reflection member 102 is made of aluminum having a predetermined thickness, and is bonded to the silicon sheet 121 by pressure bonding or a silicon-based adhesive. Also, the silicon sheet 121 is brought into close contact with the glass surface of the fluorescent lamp 101 by the predetermined method as described above.

With such a configuration, the silicon sheet 12
1 can secure a sufficient margin length so that the fluorescent lamp 101 can reliably contact the fluorescent lamp and the reflecting member even when the fluorescent lamp 101 moves.

FIG. 4 shows still another embodiment of the present invention.

In this embodiment, an independent member different from the reflecting member 102 described in the embodiment of FIGS. 1 and 3 is used as a heat radiating member.

In FIG. 4, a heat radiating member 123 is provided in a position which does not affect the exposure of the fluorescent lamp, for example, inside the upper lid 107, in the longitudinal direction and in parallel with the fluorescent lamp 101 over substantially the entire area. As this material, for example, a silicon rubber sheet having heat conductivity or heat dissipation is used. The heat dissipating member 123 has a heat coupling member 122 provided as a part thereof or as a separate member, and the heat coupling member is in close contact with the tube wall of the fluorescent lamp 101 on the opposite side from the original irradiation side. The thermal coupling with the heat radiating member 123 is performed.

Thus, in this embodiment, the size of the heat radiating member can be freely set, and the heat radiating effect can be enhanced.

[0034]

As described above, in the present invention, since the heat coupling member is provided between the tube wall of the fluorescent lamp and the heat radiating member at a position different from the original illumination side, the flashing of the fluorescent lamp is repeated. Mercury adhering to the inside of the tube wall can be forcibly attached to a position that does not affect the exposure area, and the uniformity of the exposure light amount distribution can be maintained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a lighting device embodying the present invention.

FIG. 2 is a perspective view of the vicinity of the fluorescent lamp in FIG. 1;

FIG. 3 is a sectional view of a lighting device according to another embodiment of the present invention.

FIG. 4 is a sectional view of a lighting device according to still another embodiment of the present invention.

FIG. 5 is a cross-sectional view of a lighting device as a background art of the present invention.

FIG. 6 (a) is a top view and a side view of the fluorescent lamp of FIG. 5;
(B) is a diagram showing a temperature distribution of a fluorescent lamp.

FIG. 7 is a diagram showing a temperature distribution during and immediately after turning on a fluorescent lamp.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 101 Fluorescent lamp 102 Reflecting member (heat radiating member) 120, 121, 122 Thermal coupling member 123 Heat radiating member

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Satoru Sugano 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (56) References JP-A-62-62347 (JP, A) -12155 (JP, U)

Claims (2)

(57) [Claims] 1. A fluorescent lamp having an elongated tube wall for illuminating an original, and a reflector provided along a longitudinal direction of the fluorescent lamp and reflecting a part of light emitted radially from the fluorescent lamp. And a member, wherein the reflecting member is made of metal, and is an end portion in an effective light emitting area of the fluorescent lamp and a surface side of the tube wall of the fluorescent lamp facing the reflecting member. And a heat coupling member that contacts both the tube wall of the fluorescent lamp and the reflection member. 2. The original illuminating device according to claim 1, wherein said thermal coupling member is elastically deformable.