JPH10111592A - Image reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the radiating efficiency of heat by closely bringing a reflector into contact with a supporting body without using a fitting screw and improving heat conductivity to the supporting body from the reflector. SOLUTION: A plate part 22b and a plane part 22c mutually orthogonally crossed at the lower part of the back surface of the reflector 22 and on the back surface side of the bottom surface thereof are formed. Besides, an elliptic part 22d is continuously formed at the upper part of the plate part 22 and an elliptic part 22e is continuously formed in front of the plane part 22c. Then, an aperture part 22a is formed at the elliptic part 22d. On the supporting body 23, a plane bottom surface part 23a with which the outside surface of the plane part 22c of the reflector 22 is brought into contact is formed. Besides, bent parts 23c and 23d are formed on the back surface side of the bottom surface part 23a and end part of the bent part 23d is made to abut on the outside surface of the upper end part of the plate part 22b of the reflector 22. The part of the end of the bent part 23d facing the aperture part 22a of the reflector 22 is provided with a projecting piece entering the aperture part 22a of the reflector 22 from in a back surface direction and abutting on the lower edge part of the aperture part 22a from the upper surface side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading apparatus provided with an exposure unit for irradiating a document image with light from a light source.

[0002]

2. Description of the Related Art In an image reading device such as an image reading unit or a scanner of a copying machine, an image of an original is irradiated with light from an exposure lamp, and reflected light on the image of the original is distributed to a photoconductor and an image reading element. I do. In order to read the original image faithfully,
It is necessary to uniformly irradiate a sufficient amount of light over the entire image surface of the document.A conventional image reading apparatus includes a tubular light source having a length substantially corresponding to the length of one side of the document. A reflector having a curved surface surrounding the back surface is used to reflect light emitted toward the back side of the tubular light source at the reflector, and the reflected light is condensed on the image surface of the original together with the direct light emitted toward the front side of the tubular light source. Like that.

Conventionally, a halogen lamp has been widely used as an exposure lamp constituting an exposure unit of an image reading apparatus. The periphery of a document table is heated by heat generated from the halogen lamp when exposing an image surface of a document. Failure to do so may cause a failure.

Therefore, as a conventional image reading apparatus, Japanese Patent Application Laid-Open No. HEI 5-150379 discloses that a part of a curved reflector surrounding the periphery except for a part of the light irradiation direction of a tubular light source is cut and raised. The document table, the light source, the reflection plate, and the like are cooled by an air current when the exposure unit moves from the gap.

Japanese Utility Model Application Laid-Open No. 63-98535 discloses a cooling hole at a position facing a filament of a tubular light source in a reflector surrounding a tubular light source in which a plurality of filaments are arranged at predetermined intervals. Is disclosed.

[0006]

However, in the conventional image reading apparatus, there is no method which sufficiently considers the improvement of the heat radiation efficiency of the reflector heated by the exposure lamp, and the heat radiation area becomes large, so that the entire optical device becomes large. There is a problem that leads to increase in weight and weight. Further, in the conventional image reading apparatus, since the reflector is mounted on the support using the mounting screw, a part of the mounting screw is exposed inside the reflector, and affects the light distribution balance of the light of the exposure lamp, There is a problem that the work of attaching the reflector to the support becomes complicated.

[0007] Further, in an apparatus in which an opening is formed in a part of the reflector and air flows into the inside of the reflector from this opening to cool the inside of the reflector, the inside of the reflector is opened from the outside of the reflector through the opening. No consideration is given to the airflow toward the reflector, and there has been a problem that a sufficient amount of air for cooling the exposure lamp and the reflector cannot be introduced into the inside of the reflector from the opening.

[0008] It is an object of the present invention to mount a reflector in close contact with a support without using mounting screws, improve heat conductivity from the reflector to the support, and improve the radiation efficiency of the reflector. Provided is an image reading apparatus that can reduce the heat radiation area, realize the miniaturization and weight reduction of the entire apparatus, prevent fluctuation of the light distribution balance inside the reflector, and simplify the work of attaching the reflector to the support. Is to do.

Further, by providing an airflow plate for forming an air flow path from the outside of the reflector to the inside of the reflector via the opening, a sufficient amount of air for cooling the exposure lamp and the reflector is supplied from the opening to the reflector. An object of the present invention is to provide an image reading device that can be introduced inside.

[0010]

According to a first aspect of the present invention, there is provided a tubular light source for irradiating an image on a document with light, a reflector surrounding the tubular light source, and a support for supporting the reflector. In an image reading apparatus provided with a plurality of openings formed in a reflector facing a tubular light source, a flat portion which is in close contact with a flat portion of a support over a whole range in a longitudinal direction of the light source on a part of the reflector, and which is orthogonal to the flat portion. Flat part,
And, forming an elliptical portion continuous above the flat plate portion, the opening portion is provided in the elliptical portion with the upper end of the flat plate portion as a lower edge, and the flat portion is brought into contact with the lower edge of the opening portion on the support from above. And a projection that sandwiches the flat portion of the reflector is formed therebetween.

Therefore, in the invention described in claim 1, a part of the reflector comes into surface contact with the support,
The thermal conductivity from the reflector to the support is improved. Further, the reflector has the flat plate portion sandwiched between the projecting portion of the support and the flat portion, and does not require mounting screws or the like for fixing the reflector to the support.

According to a second aspect of the present invention, there is provided an airflow plate, wherein an upper end of the elliptical portion is horizontally bent to the outside of the reflector to form an air flow path from the outside of the reflector to the inside of the reflector via the opening. It is characterized by having been provided.

Therefore, according to the second aspect of the present invention, the airflow plate formed by bending the upper end of the elliptical portion of the reflector is formed from the outside of the reflector to the inside of the reflector via the opening. Air sufficient to cool the exposure lamp or reflector is introduced inside the reflector.

The invention described in claim 3 is characterized in that the airflow plate is a mounting member for a light control plate for fixing the light control plate on the upper surface.

Therefore, according to the third aspect of the present invention, since the light control plate is mounted on the upper surface of the airflow plate exposed outside the reflector, a part of the mounting screw used for mounting the light control plate is formed inside the reflector. There is no exposure.

[0016]

FIG. 1 is a schematic diagram showing a structure of a main part of an image forming apparatus provided with an image reading apparatus according to an embodiment of the present invention. The image forming apparatus main body 1 is provided with a photoreceptor 2 having a photoconductive layer formed on the surface so as to be rotatable in the direction of arrow C.
Further, a charger 3 for charging the surface of the photoreceptor 2 with a single-polarity charge is provided facing the periphery of the photoreceptor 2, and a developer is supplied to the surface of the photoreceptor 2 to form an electrostatic latent image on the developer image. And a transfer device 5 for transferring the developer image from the surface of the photoreceptor 2 to a transfer sheet.

An optical device 8 housed in a housing 9 is disposed above the main body 1 of the image forming apparatus. Optical device 8
Are the exposure lamp 8a, the first mirror 8b to the sixth mirror 8g.
And a lens 8h. The exposure lamp 8a is a tubular light source such as a halogen lamp. The exposure lamp 8a and the first mirror 8b are mounted on the lamp unit 10,
The second mirror 8c and the third mirror 8d are a mirror base 11
And a fourth mirror 8e and a fifth mirror 8f
Is mounted on the support 21.

Lamp unit 10 and mirror base 11
Reciprocates in the directions of arrows A and B in parallel with the platen 7 below the platen 7 fixed to the upper surface of the housing 9. Due to the reciprocating movement of the lamp unit 10 and the mirror base 11, the image surface of the document placed on the document table 7 is optically scanned by the exposure lamp 8a, and the light of the exposure lamp 8a is sequentially applied to the entire image surface of the document. Is irradiated. Exposure lamp 8
The light reflected on the image surface of the original is reflected by the first mirror 8.
The light is distributed to the surface of the photoconductor 2 that has been charged by the charger 3 via the b to sixth mirror 8g and the lens 8h.

In this way, the surface of the photoreceptor 2 charged by the charger 3 is exposed by the reflected light on the image surface of the original, and the surface of the photoreceptor 2 is converted into image information of the original by photoconductive action. An electrostatic latent image is formed.

As described above, in order to reciprocate the lamp unit 10 and the mirror base 11 below the document table 7, the wire 16 and the motor 17 stretched by the pulleys 12 to 15 are provided in the housing 9. ing. In addition,
Inside the housing 9, a guide shaft (not shown) is provided in parallel with the document table 7 and the longitudinal direction thereof coincides with the moving direction of the lamp unit 10 and the mirror base 11, and the guide shaft is provided with a lamp. The unit 10 and the mirror base 11 are fitted and slid.

Among the pulleys 12 to 15 that stretch the wire 16, the pulley 12 is supported by the mirror base 11, and the other pulleys 13 to 15 are supported by the housing 9. One end of the wire 16 is fixed to a fixing plate 18 protruding from the housing 9, and the other end of the wire 16 is fixed to a fixing plate 20 protruding from the housing 9 via a spring 19. The wire 16 is wound around the pulley 12 over a half circumference starting from one end fixed to the fixing plate 18,
It is fixed to the lamp unit 10, is wound around the pulley 16 once or more via the pulley 14, and is fixed to the fixed plate 20 via the spring 19 at the other end via the pulley 13 and the pulley 12. .

Since the wire 16 is stretched on the pulleys 12 to 15 in the above state, when the pulley 15 is driven clockwise in the drawing, the lamp unit 10 and the mirror base 11 move in the direction of arrow A in the drawing. It moves and scans the image surface of the document placed on the document table 7. At this time, since the driving force is transmitted to the mirror base 11 via the pulley 12,
The moving speed of the mirror base 11 is always the lamp unit 10
Moving speed is half. As a result, the optical path length of the reflected light from the image surface of the original to the surface of the photoconductor 2 via the mirrors 8b to 8g and the lens 8g is always kept constant.

The lens 8g and the support 21 are indicated by arrows A
Alternatively, by moving in the direction B, the relationship between the distance from the image surface of the document to the lens 8g and the distance from the lens 8g to the surface of the photoconductor 2 changes, and the magnification of the image formed on the surface of the photoconductor 2 is changed. Can be changed.

FIGS. 2 to 4 are a plan view, a side view and a rear view of the lamp unit of the image forming apparatus. The lamp unit 10 includes contact plates 26 and 27 that support both ends of the exposure lamp 8a, lamp holders 28 and 29 made of an insulating material that holds the contact plates 26 and 27, respectively, and a reflector that surrounds the periphery of the back side of the exposure lamp 8a. 22, a support 23 for supporting the reflector 22, and a plurality of dimming plates 24 mounted on the upper surface of the reflector 22 via mounting screws 25.

The reflector 22 surrounds the periphery of the back side of the exposure lamp 8a, reflects light emitted from the exposure lamp 8a, and condenses the light toward the document table 7. For this reason, a part of the cross section of the reflector 22 is formed in an elliptical shape in which the exposure lamp 8a is located at one focal point and the bottom surface of the document table 7 is located at the other focal point. In the reflector 22, a plurality of openings 22a are formed over substantially the entire range in the longitudinal direction. Each of the plurality of openings 22a is provided with an exposure lamp 8a.
At a position opposite to the position where the filament, which is a light emitting luminescent spot, is arranged, and is exposed on the back side of the lamp unit 10.

FIG. 5 is a side sectional view taken along the line XX shown in FIG. As shown in FIG. 5, the reflector 22 includes a flat plate portion 22b and a flat plate portion 22c that are orthogonal to each other below the rear surface and on the rear surface side of the bottom surface. An elliptical portion 22d is formed continuously above the flat plate portion 22b, and an elliptical portion 22e is formed continuously in front of the flat portion 22c. The elliptical portion 22d and the elliptical portion 22e are both parts of the same ellipse, and the elliptical portion 22d has an opening 22a.
Are formed.

Further, the upper end of the elliptical portion 22d is bent in a flat shape on the back side to form a mounting portion 22f (the airflow plate of the present invention). The light control plate 24 is mounted on the upper surface of the mounting portion 22f via mounting screws 25. Therefore, the light emitted from the exposure lamp 8a
The opening 2 formed directly between the upper end of the elliptical portion 22e and the front end of the light control plate 24 after being reflected on the flat plate portion 22b, the flat surface portion 22c, and the elliptical portions 22d and 22e.
Light is distributed from 2 g in the direction of the platen.

The support 23 has a flat bottom surface 23a with which the outer surface of the flat surface 22c of the reflector 22 contacts.
(This is a plane part of the present invention.) An inclined portion 23b is continuously formed in front of the bottom portion 23a, and the elliptical portion 22e of the reflector 22 is formed on the inclined portion 23b.
The outer surface of the abutment. The back side of the bottom portion 23a of the support 23 is formed with bent portions 23c and 23d which are bent twice at right angles. The end of the bent portion 23d contacts the outer surface of the upper end portion of the flat plate portion 22b of the reflector 22.

Further, a protruding piece 23e is formed at a portion of the end of the bent portion 23d facing the opening 22a of the reflector 22. The protruding piece 23e penetrates into the opening 22a of the reflector 22 from the back side, and contacts the lower edge of the opening 22a from the upper surface side.

A not-shown thermal fuse is provided on the outer surface of the elliptical portion 22e of the reflector 22. The thermal fuse cuts off the drive circuit of the exposure lamp 8a when the elliptical portion 22e of the reflector 22 rises above the set temperature.

With the above-described structure, the reflector 22 is in contact with the outer surface of the elliptical portion 22e and the inclined portion 23b of the support 23, and the end of the outer surface of the elliptical portion 22d and the bent portion 23d of the support 23. The horizontal movement with respect to the support 23 is restricted by the contact with the part. Further, the flat plate portion 22b of the reflector 22 is connected to the bottom surface portion 23a of the support 23 and the protruding portion 23e.
And the vertical movement of the reflector 22 with respect to the support 23 is restricted.

Therefore, the entire surface of the outer surface of the flat portion 22c of the reflector 22 can be supported by the support 2 without using mounting screws.
3 can be securely brought into close contact with the bottom surface 23a. Thereby, the heat generated by the lighting of the exposure lamp 8a is easily conducted to the support 23 through the reflector 22, and the heat radiation efficiency can be improved. The temperature of the reflector 22 is reduced when the reflector 22 is not brought into close contact with the support 23. Was able to be lowered by about 15 ° C. Further, the reflector 22 can be reduced in size by improving the heat radiation efficiency, and the overall size and weight of the optical device 8 can be reduced.

Further, the mounting screws are not exposed inside the reflector 22 surrounded by the flat plate portion 22b, the flat portion 22c and the elliptical portions 22d and 22e, so that the light distribution balance is not changed and the number of components is reduced. Reduction and simplification of assembly work can be achieved. Further, the support 2
3 is formed in a direction perpendicular to the flat plate portion 22b of the reflector 22, the contact portion between the projecting piece 23e and the opening 22a of the reflector 22 is formed.
3 acts on the reflector 22 in a downward direction to prevent the reflector 22 from being deformed.
The occurrence of an error in the light distribution balance at 0 can be reliably prevented.

In the reflector 22, the mounting portion 2
2f protrudes rearward from the flat plate portion 22b by a length L to form a space surrounded by the mounting portion 22f, the elliptical portion 22d, and the bent portion 23d. When the lamp unit 10 moves in the direction of arrow A during scanning of an image on a document, air located in front of the lamp unit 10 is stored in this space, and an air flow path from the opening 22a to the inside of the reflector 22 is provided. Can be formed, and the reflector 2
A large amount of air can be introduced into the inside of the container.

As shown in FIG. 6, the rear side of the light control plate 24 extends rearward from the mounting portion 22f, so that more air in front of the lamp unit 10 that moves during scanning of a document image. Can be guided from the opening 22 a to the inside of the reflector 22 by the lower surface of the light control plate 24. Thereby, the heat radiation efficiency of the reflector 22 can be improved, and the temperature of the reflector 22 is further reduced to 10 ° C.
Could be reduced to some extent. In addition, since the heat radiation efficiency is improved, the heat radiation area of the reflector 22 can be reduced, and the size and weight of the entire optical device 8 can be reduced.

Further, the mounting screw 25 of the light control plate 24 is screwed into a mounting portion 22f protruding outside the reflector 22. For this reason, a part of the mounting screw 25 is not exposed inside the reflector 22 that reflects the light of the exposure lamp 8a, and does not affect the light distribution balance of the light of the exposure lamp 8a.

In addition, as is apparent from FIG. 3, the reflector 22 and the lamp holders 28 and 29 are provided with the exposure lamp 8a.
Are open to the outside, so that the flow of air in the axial direction of the exposure lamp 8a inside the reflector 22 is improved. Therefore, as shown in FIG. 7, the blower fan is provided at the lamp holder 29 side of the lamp unit 10 or at a position facing the lamp holder 29 side of the lamp unit 10 at the stop position in the housing 9 of the optical device 8. Accordingly, air can be blown from the lamp holder 29 side to the lamp holder 28 side to the inside of the reflector 22, the exposure lamp 8a and the reflector 22 can be sufficiently cooled, and the heat radiation efficiency is further improved.

[0038]

According to the first aspect of the present invention, a part of the reflector is brought into surface contact with the support to improve the heat conductivity from the reflector to the support, thereby improving the heat radiation efficiency of the reflector. As a result, the overall size and weight of the optical device can be reduced by reducing the heat radiation area of the reflector. Further, since the flat plate portion of the reflector is sandwiched between the projecting portion of the support and the flat portion, a mounting screw for fixing the reflector to the support becomes unnecessary, and the work of mounting the reflector on the support can be simplified, Part of the mounting screw is not exposed inside the reflector, and the light distribution balance of the reflector is not changed.

According to the second aspect of the present invention, the airflow plate formed by bending the upper end of the elliptical portion of the reflector is formed from the outside of the reflector to the inside of the reflector via the opening, A sufficient amount of air to cool the exposure lamp and reflector can be introduced inside the reflector, improving the cooling efficiency of the optical device and reducing the heat radiation area of the reflector, etc., and reducing the size and weight of the entire optical device Can be realized.

According to the third aspect of the present invention, since the light control plate is mounted on the upper surface of the airflow plate exposed outside the reflector, a part of the mounting screw used for mounting the light control plate is provided inside the reflector. There is no exposure, and the light distribution balance of the reflector is not changed.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating a structure of a main part of an image forming apparatus including an image reading device according to an embodiment of the present invention.

FIG. 2 is a plan view of a lamp unit of the image forming apparatus.

FIG. 3 is a side view of a lamp unit of the image forming apparatus.

FIG. 4 is a rear view of a lamp unit of the image forming apparatus.

FIG. 5 is a side sectional view of the lamp unit taken along line XX in FIG. 4;

FIG. 6 is a side sectional view of a lamp unit of an image reading apparatus according to another embodiment of the present invention.

FIG. 7 is a plan view of a lamp unit of an image reading apparatus according to still another embodiment of the present invention.

[Explanation of symbols]

 1-Copier body 2-Photoreceptor 8a-Exposure lamp 9-Housing 10-Lamp unit 22-Reflector 22a-Opening 22b-Flat portion 22c-Flat portion 22d-Elliptical portion 22e-Elliptical portion 22f-Mounting portion (airflow Plate) 23-support 23a-bottom part 23e-projecting piece 24-light control plate 25-mounting screw

Claims (3)

[Claims] A light source for irradiating light on an image of a document;
In an image reading apparatus including a reflector surrounding the periphery of the light source and a support for supporting the reflector, and a plurality of openings facing the light source formed in the reflector, a part of the reflector extends over the entire range in the longitudinal direction of the light source. A flat part that is in close contact with the flat part of the support, a flat part orthogonal to the flat part, and an elliptical part that is continuous above the flat part are formed, and the opening is provided in the elliptical part with the upper end of the flat part as the lower edge. An image reading device, wherein a protruding piece that abuts a lower edge of the opening on the support from above and sandwiches a flat plate portion of the reflector between the flat portion and the flat portion. 2. The air flow plate according to claim 1, wherein an upper end of the elliptical portion is horizontally bent outside the reflector, and an air flow plate is provided to form an air flow path from the outside of the reflector to the inside of the reflector via the opening. Image reading device. 3. The image reading apparatus according to claim 2, wherein the airflow plate is a mounting member for a light control plate for fixing the light control plate on an upper surface.