JP3040850B2 - Illumination device for document reader - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an illumination device for a document reading apparatus.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 4, a document placed on a transparent document table 1 is illuminated by a fluorescent lamp 2 and a reflected image of the document is reflected by mirrors 3, 4, and 5 and is reflected by a lens 6. There is a document reading device that forms an image on a light receiving unit 7 such as a CCD image sensor (or a light receiving unit such as a photoconductor).

Conventionally, an original was illuminated by an aperture-type fluorescent lamp. Recently, however, there has been a high demand for miniaturization. Therefore, a small-diameter fluorescent lamp 2 having a diameter of 10 mm or less is frequently used. A conductive material is provided along the lamp 2, and a heating member 17 is fixed to the back of the fluorescent lamp 2 with an adhesive sheet 18 as shown in FIGS. 5 and 6.
7, the temperature of the fluorescent lamp 2 is increased.
It is also known to stabilize the amount of light.

[0004]

As shown in FIGS. 5 and 6, when a small-diameter fluorescent lamp 2 having a diameter of 10 mm or less is formed into an aperture type, it becomes difficult to form a reflective film and an opening in a tube. Although the full emission type is frequently used because the manufacturing cost is high, the full emission type fluorescent lamp 2 has poor luminous efficiency. Even if conductive and highly reflective aluminum is used for the adhesive sheet 18, since the adhesive is applied to the inner surface of the aluminum, there is an effect of preventing lighting failure due to the conductivity of aluminum, but the improvement of the reflectance is achieved. Not be. Further, since the fluorescent lamp 2 has a small diameter, the intensity is low and the breakage rate is high. Further, since the light from the fluorescent lamp 2 illuminates the platen 1 directly above the fluorescent lamp 2 with the strongest light,
The reflected light from the document table 1 returns to the fluorescent lamp 2 and the light amount to the reading line 9 changes, so that a correct reflected light amount for the document cannot be obtained.

[0005]

According to a first aspect of the present invention, a document placed on a document table is illuminated by a straight-tube, full-surface-emitting, small-diameter fluorescent lamp, and an image of the document is passed through an optical element. In the document reading device that forms an image on the light receiving unit, a reinforcing member formed of a material having high rigidity and conductivity is provided while surrounding and holding the back surface of the fluorescent lamp on the side opposite to the document table. A reflection surface having a high reflectance was formed on the back side of the fluorescent lamp of the member.

According to a second aspect of the present invention, in the first aspect, the reinforcing member is formed of a material having a high thermal conductivity, and
A heating element was attached to the material .

[0007]

[0008]

[0009]

According to the first aspect of the present invention, since the back side of the fluorescent lamp is surrounded by the reinforcing member, light can be emitted from the fluorescent lamp only in the reading line direction, and the back side of the fluorescent lamp can be reflected. Since the reflective surface having a high efficiency is formed, the luminous efficiency can be improved. Further, the fluorescent lamp can be reinforced with a reinforcing member to prevent damage before it occurs.

[0010]

According to the second aspect of the present invention, the heat of the heating element can be transmitted to the fluorescent lamp by the reinforcing member having high thermal conductivity to stabilize the light quantity of the fluorescent lamp.

[0012]

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. The same parts as those described with reference to FIG. A reinforcing member 8 made of a material having high rigidity is provided so as to be able to reciprocate along the lower surface of the document table 1. A small-diameter fluorescent lamp 2 of a straight tube type and a full-surface light emission type is provided. Then, two tangential lines 1 are connected to the reading line 9 of the document table 1 from both sides of the outer periphery of the fluorescent lamp 2.
A gutter-shaped holding portion 12 that surrounds and holds the back surface of the fluorescent lamp 2 on the opposite side to the direction in which 0 and 11 are directed, and a rod-shaped heating element 13
Is formed on the reinforcing member 8. On the back side of the fluorescent lamp 2 of the reinforcing member 8, a reflection surface 15 having a high reflectance is formed.

In such a configuration, since the rear side of the fluorescent lamp 2 is surrounded by the reinforcing member 8, light can be emitted from the fluorescent lamp 2 only in the reading line 9 direction. Since the reflection surface 15 having a high reflectance is formed on the side, the luminous efficiency can be improved. Further, the fluorescent lamp 2 can be reinforced by the reinforcing member 8 to prevent damage before it occurs.

Further, by forming the reinforcing member 8 from a material having conductivity, the holding portion 12 can be formed as a close conductor along the fluorescent lamp 2, thereby preventing defective lighting of the fluorescent lamp 2. Can be. Further, by forming the reinforcing member 8 with a material having high thermal conductivity, the heating element 13
The heat of the fluorescent lamp 2 can be stabilized by transmitting the heat of the fluorescent lamp 2 to the fluorescent lamp 2 by the reinforcing member 8 having a high thermal conductivity.

Further, as shown in FIG. 3, a light-shielding piece 16 extending toward the original table 1 along a tangent line 10 on the outer periphery of the fluorescent lamp 2 is formed on the reinforcing member 8 so that the original from the fluorescent lamp 2 Since the illumination light to the portions other than the reading line 9 of the table 1 is shielded by the light shielding pieces 16, the reflected light returning from the periphery of the reading line 9 to the fluorescent lamp 2 can be limited.
The change in the amount of light on the reading line 9 can be suppressed, and the image of the document can be reproduced faithfully.

[0017]

According to the first aspect of the present invention, a document placed on a document table is illuminated by a straight-tube, full-surface-emitting, small-diameter fluorescent lamp, and the image of the document is connected to a light-receiving portion through an optical element. In the document reading apparatus for imaging, the fluorescent lamp surrounds and holds the rear surface of the fluorescent lamp opposite to the document table and has high rigidity.
Providing a reinforcing member formed of a conductive material,
Since a reflective surface having a high reflectance is formed on the back side of the fluorescent lamp of the reinforcing member, since the rear side of the fluorescent lamp is surrounded by the reinforcing member, light is emitted from the fluorescent lamp only in the reading line direction. In addition, since the reflective surface with high reflectivity is formed on the back side of the fluorescent lamp, the luminous efficiency can be improved, and the fluorescent lamp is reinforced with a reinforcing member to prevent damage before it occurs And the like.

[0018]

The invention of claim 2 is Oite to claim 1, the reinforcing member is formed by a material having high thermal conductivity, so mounting the heating element to the reinforcing member, the heating element heat thermal conductivity There is an effect that the light can be stabilized by transmitting to the fluorescent lamp by the high reinforcing member.

[0020]

[Brief description of the drawings]

FIG. 1 is a front view of a part of a lighting device in a cross section according to an embodiment of the present invention.

FIG. 2 is a perspective view thereof.

FIG. 3 is a front view of a part of the lighting device in a cross section.

FIG. 4 is a front view showing the internal structure of a conventional document reading apparatus.

FIG. 5 is a front view showing a part of the lighting device in section.

FIG. 6 is a perspective view thereof.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Original table 2 Fluorescent lamp 3-6 Optical element 7 Light receiving part 8 Reinforcement member 9 Reading line 13 Heating element 15 Reflection surface

Claims (2)

(57) [Claims] 1. A document reading apparatus for illuminating a document placed on a document table with a straight-tube, full-surface-emitting, small-diameter fluorescent lamp, and forming an image of the document on a light receiving unit through an optical system element. A reinforcing member made of a material having high rigidity and conductivity is provided to surround and hold the rear surface of the fluorescent lamp opposite to the original table, and the reinforcing member is reflected on the rear surface side of the fluorescent lamp. An illumination device for a document reading apparatus, wherein a reflection surface having a high efficiency is formed. 2. The reinforcing member is formed of a material having high thermal conductivity.
2. The illumination device according to claim 1 , wherein a heating element is mounted on the reinforcing member .