JP2002162699A - Image reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image reader by which a good-quality read image without blurring is obtained over a long term by suppressing the vibration of a scanning optical system by a simple constitution. SOLUTION: The image reader to read an image by scanning an original by an optical system having an optical mirror such as a second mirror 27 and a third mirror 28 is provided with a reinforcing member 30 fixed to at least adjacent two surfaces 27a and 27b (28a and 28b) out of the surfaces of the optical mirror 27 (28) along longitudinal direction to reinforce the optical mirror 27 (28).

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 as an image reading means provided in an image forming apparatus such as a copying machine or a facsimile, or a single image reading apparatus such as a scanner.

[0002]

2. Description of the Related Art Conventionally, as an image forming apparatus having an image reading apparatus of this type, for example, an image forming apparatus having a configuration as shown in FIG. 5 is known.

FIG. 5 is a schematic sectional view of the structure of an image forming apparatus. In FIG. 5, an image forming apparatus main body A has a scanner section B as an image reading means for reading image information such as a book document at an upper portion thereof, and an image forming section C as an image forming means at a lower portion thereof. Further, a seat deck D is attached to a lower portion thereof.

[0004] The scanner section B is a platen glass 2
02, a document pressure plate 203 that can be opened and closed with respect to the scanning body A,
First mirror base 20, second mirror base 21, lens barrel 2
2. It has a CCD sensor 23 and an image processing unit.

The first mirror table 20 is provided with an exposure lamp 24 for irradiating the original surface, a reflection shade 25, and a first mirror 26 for changing the direction of the reflected light of the irradiated original by 90 degrees. The second mirror base 21 is provided with a second mirror 27 and a third mirror 28 that fold reflected light coming from the first mirror base by 180 degrees. The reflected light reflected by the second mirror base 21 passes through the lens barrel 22 and forms an image on the CCD sensor 23.

[0006] First mirror stand 20 and second mirror stand 21
Is supported by a rail (not shown) and is movable on the rail. The first mirror base 20 and the second mirror base 21 are driven by wires (not shown), drive shafts, pulleys, stepping motors, and the like so that the optical path length from the document surface to the CCD sensor 23 is always constant.

Here, the first mirror base 20 and the second mirror base 21 constitute a scanning optical system for scanning a document, and the first mirror 26, the second mirror 27 and the third mirror as optical mirrors.
A mirror 28 is provided.

A description will be given of a processing operation when copying an original in the image forming apparatus having the above configuration.

First, a book document, a sheet document, or the like such as a book, thick paper, or curled paper is placed on the platen glass 202 with the document surface facing down. When the reading start key is pressed, the exposure lamp 24 scans the lower part of the platen glass 202 in the direction of arrow a in FIG.

The light reflected from the original surface, that is, the image information of the original, is turned back by the first mirror 26, the second mirror 27, and the third mirror 28, and is passed through the lens barrel 22 to C
It is read by the CD sensor 23. The image information of the document thus read is processed by the image processing unit, converted into an electric signal, and transmitted to the laser scanner 111.

The laser scanner 111 irradiates the surface of the photosensitive drum 112 with a laser beam based on the electric signal to form an electrostatic latent image corresponding to the original image. After the electrostatic latent image is developed with the toner, the electrostatic latent image is transferred onto the sheet S fed from the sheet feeding cassette 1, the sheet deck D or the manual feed tray 10 in synchronization with the image forming timing. After undergoing the toner image fixing process, the sheet S is discharged to the discharge tray 120.

The image forming apparatus main body A functions as a copying machine when a processing signal of the image processing unit is input to the laser scanner 111, and functions as a printer when an output signal of the computer is input. Further, if a signal from another facsimile apparatus is received or a signal from the image processing unit is transmitted to another facsimile apparatus, the apparatus functions as a facsimile apparatus.

In an image reading apparatus having a scanning optical system as described above, if each mirror vibrates greatly during scanning, the light incident on the CCD sensor 23 will be slightly shifted. What is a straight line,
It is reproduced with shaking and distortion.

In order to solve this problem, Japanese Patent Application Laid-Open No. Hei 8-1
06129 and JP-A-10-282399 have been proposed. Japanese Patent Application Laid-Open No. 8-106129 discloses that a reinforcing member having high flatness is attached to the back surface of a mirror,
The idea was to control the vibration without damaging the flatness of the mirror. Japanese Patent Application Laid-Open No. H10-282399 discloses a technique in which a reinforcing member is attached to the side surface of a mirror to achieve both the flatness of the mirror and the vibration damping effect.

[0015]

However, in the case of the above-described prior art, the following problems have occurred.

First, in JP-A-8-106129, a reinforcing member is attached to the back surface of a mirror. However, since the normal mirror vibrates in the direction indicated by the arrow in FIG. 6, if the vibration is suppressed by attaching a reinforcing member to the back surface of the mirror, the section modulus of the reinforcing member should be increased in accordance with the strength of the vibration. There must be.

That is, in order to suppress strong vibration with the configuration proposed in Japanese Patent Application Laid-Open No. H08-106129, the thickness of the reinforcing member must be increased, or the mirror 12 shown in FIG.
It is necessary to increase the bending height of the reinforcing member 130 by bending the reinforcing member 130 in the direction of the rear surface of the base member 7 or 128. When the thickness of the reinforcing member is increased, the mirror becomes heavy and the output torque of the drive motor must be increased. When the bending of the reinforcing member is increased, a large space is required on the back surface of the mirror.

On the other hand, in JP-A-10-282399,
A configuration in which a reinforcing member is attached to a side surface of a mirror has been proposed. In this configuration, when the mirror vibrates as shown in FIG. 6, a shearing force is generated on the bonding surface between the mirror and the reinforcing member. Further, since the reinforcing member is attached to the side end surface of the mirror, the attaching area is relatively small. As a result, the reinforcing member may be easily peeled off due to a temporal change after the application or a repeated impact due to the movement of the mirror base.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art. It is an object of the present invention to suppress vibration of a scanning optical system with a simple configuration, and to provide a high-quality, long-term vibration-free image. An object of the present invention is to provide an image reading device capable of obtaining a read image.

[0020]

According to the present invention, there is provided an image reading apparatus for scanning an original by using an optical system having an optical mirror to read an image.
The optical mirror further includes a reinforcing member fixed to at least two adjacent surfaces among the surfaces along the longitudinal direction of the optical mirror and reinforcing the optical mirror.

Since the reinforcing member is fixed to a plurality of adjacent surfaces of the optical mirror, the rigidity of the reinforcing member itself can be increased, and the bonding strength to the optical mirror can be increased. As a result, high vibration suppression can be achieved. The effect can be maintained for a long time.

The reinforcing member is preferably a sheet metal bent along a plurality of fixing surfaces with the optical mirror.

By providing the bent portion, the section modulus of the sheet metal is increased, and sufficient rigidity and vibration damping effect can be obtained even with a thin sheet metal, so that the size and weight of the reinforcing member can be reduced. . Further, since the bent portion is formed along the fixing surface with the optical mirror, a small space around the optical mirror can be achieved.

Further, it is preferable that an elastic member is interposed between the reinforcing member and the optical mirror.

Thus, it is possible to prevent the flatness of the reinforcing member from affecting the flatness of the optical mirror, so that a higher quality image can be read.

Further, it is preferable that the reinforcing member extends to the vicinity of both ends in the longitudinal direction of the optical mirror.

Thus, the vibration damping effect of the optical mirror can be further enhanced.

[0028]

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, the dimensions of the components described in this embodiment,
The materials, shapes, relative arrangements, and the like are not intended to limit the scope of the present invention only to them unless otherwise specified.

(First Embodiment) An image reading apparatus according to a first embodiment of the present invention will be described with reference to FIGS.

Since the configurations of the image reading apparatus and the image forming apparatus are substantially the same as those described in the prior art, in the following description, the same components as those in the conventional example are denoted by the same reference numerals. The description thereof will be omitted, and only different components will be described in detail.

FIG. 1 is a front view showing a second mirror base 21 of the image reading apparatus according to the present embodiment. FIG. 2 shows only the optical mirror of the second mirror base 21, and FIG. 3 shows only the second mirror 27 in a perspective view.

As shown in FIG. 2, the second mirror 27 and the third
The mirrors 28 are disposed at an angle of 90 degrees so as to face each other's reflection surfaces, and each mirror is provided with a reinforcing member 30 for reinforcing the strength of the mirror and preventing vibration. . Since the second mirror 27 and the third mirror 28 are mirrors having the same configuration symmetrically arranged, only the second mirror 27 will be described below.

As shown in FIGS. 2 and 3, the reinforcing member 3
No. 0 is manufactured by bending a sheet metal at 90 degrees,
0a and a side surface adhesive portion 30b which is a bent portion orthogonal thereto.
It is composed of The length in the longitudinal direction is substantially the same as the length of the second mirror 27, and extends to the vicinity of both ends of the second mirror 27.

That is, the reinforcing member 30 is connected to the second mirror 2.
7, a back surface 27a opposite to the reflection surface, and a side surface 2 facing the scanning direction (arrow X in the drawing).
7b is bent so as to be in contact with two adjacent surfaces, and the back surface bonding portion 30a is formed on the back surface 27a of the second mirror 27.
In addition, the side surface adhesive portion 30b is attached and fixed to the side surface 27b with a double-sided tape.

Although the reinforcing member 30 is made of sheet metal, it is lightweight, but has a higher section modulus than that of a flat plate due to the presence of a bent portion. Conversely, the side bonding portion 30b
This increases the rigidity of the back surface bonding portion 30a in the bending direction, so that the plate thickness can be reduced as compared with a case where the reinforcing member is formed of a flat plate.

Further, since the side surface adhesive portion 30b, which is a bent portion of the reinforcing member 30, is processed along the side surface 27b of the second mirror 27, the length of the bent portion and the thickness of the mirror cancel each other out, and FIG. There is no need for a large space behind the mirror as in the conventional example.

That is, according to the above configuration, the second mirror 27 can be compactly reinforced by the reinforcing member 30 having a light weight and a high section modulus. Also, the second mirror 2
7 can be restrained at the same time, so that it is possible to obtain a high vibration damping effect and prevent the reinforcing member 30 from peeling off, in a conventional configuration in which only one surface of the back surface or only one side surface is restrained. be able to.

Therefore, in the image reading apparatus according to the present embodiment having such an optical mirror, it is possible to obtain a high-quality read image without blurring for a long time.

In this embodiment, the back surface 2 of the mirror is used.
7a and the reinforcing member 30 only on the side surface 27b facing the scanning direction X.
However, it is needless to say that the back surface 27a and the other side surface 27c may be reinforced, or the back surface 27a and the side surfaces 27b and 27c may be reinforced. In the latter case, the reinforcing member 30 has a U-shaped cross section.

In this embodiment, only the reinforcement of the second mirror 27 and the third mirror 28 of the image reading apparatus is described. However, it is needless to say that the present invention can be suitably applied to other optical mirrors such as the first mirror 26. .

Further, the reinforcing member 30 does not necessarily have to be formed by bending a sheet metal. Any material other than metal may be used as long as it has sufficient rigidity, and may be a member formed or assembled into a shape along the bonding surface with the mirror.

(Second Embodiment) FIG. 4 shows a second embodiment of the present invention. In the present embodiment,
The configuration in which an elastic member is interposed between the reinforcing member and the optical mirror is shown.

Since other structures and operations are the same as those of the first embodiment or the conventional example, the same components are denoted by the same reference numerals and description thereof will be omitted. Further, in the following description, the second mirror 27 will be described as an example, but other optical mirrors such as the third mirror 28 can be similarly applied.

FIG. 4 is a diagram showing a configuration of an optical mirror of the image reading apparatus according to the present embodiment.
Second mirror 27 and third mirror 28 and their reinforcing members 3
0 is shown.

In the present embodiment, the second mirror 27
The elasticity of the double-sided tape is different between the side surface 27b and the back surface 27a. The side surface 27b of the second mirror 27 is pasted using a conventional thin and weakly elastic double-sided tape,
The back surface 27a of the second mirror 27 is adhered via a thick double-sided tape 31 (elastic member) with high elasticity.

Generally, the flatness of the attaching surface of the mirror reinforcing member is inferior to that of the optical mirror, and attaching the reinforcing member greatly affects the flatness of the reflecting surface of the optical mirror.

However, in the present embodiment, the influence of the flatness of the reinforcing member 30 can be reduced by interposing the elastic double-sided tape 31, and the flatness of the optical mirror in a higher dimension such as a color copying machine can be reduced. When required, a high anti-vibration effect can be obtained without impairing the flatness of the optical mirror.

At this time, the attachment of the reinforcing member 30 to the side surface 27b of the second mirror 27 has less influence on the flatness of the second mirror 27 than the case of attachment to the back surface 27a. What is necessary is just to use the same elastic double-sided tape as a form.

In this embodiment, the double-sided tape having elasticity is used. However, it may be fixed by sandwiching an elastic material such as rubber or sponge.

[0050]

As described above, according to the present invention, since the reinforcing member is fixed to a plurality of adjacent surfaces of the optical mirror, the rigidity of the reinforcing member itself is increased and the bonding strength to the optical mirror is improved. The vibration of the scanning optical system can be effectively suppressed with such a simple configuration, and a high-quality read image free from blurring can be obtained for a long period of time.

Further, by providing a bent portion along a plurality of fixing surfaces with the optical mirror, a reinforcing member having a lightweight and high vibration damping effect can be attached to the optical mirror without taking a large space.

Further, if an elastic member is interposed between the reinforcing member and the optical mirror, it is possible to prevent the flatness of the reinforcing member from affecting the flatness of the optical mirror. Image reading becomes possible.

[Brief description of the drawings]

FIG. 1 is a front view showing a mirror base of an image reading apparatus according to a first embodiment of the present invention.

FIG. 2 is a front view showing the configuration of the optical mirror of FIG.

FIG. 3 is a perspective view of the optical mirror of FIG. 2;

FIG. 4 is a front view illustrating a configuration of an optical mirror of an image reading apparatus according to a second embodiment of the present invention.

FIG. 5 is a schematic cross-sectional view of an image forming apparatus having a conventional image reading apparatus.

FIG. 6 is a schematic diagram showing a state in which an optical mirror vibrates.

FIG. 7 is a front view showing a configuration of a conventional optical mirror.

[Explanation of symbols]

 Reference Signs List 20 first mirror base 21 second mirror base 22 lens barrel 23 CCD sensor 24 exposure lamp 25 reflection shade 26 first mirror (optical mirror) 27 second mirror (optical mirror) 28 third mirror (optical mirror) 30 reinforcing member 30a Backside bonding part 30b Side bonding part 31 Double-sided tape (elastic member)

(72) Inventor Takashi Kaga 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Osamu Okamoto 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Akihiro Kashiwara 3-30-2 Shimomaruko, Ota-ku, Tokyo F-term in Canon Inc. (reference) 2H108 AA01 CA03 CB01 HA05 5C072 AA01 BA13 CA06 DA04 DA21 DA23 EA05 HA02 XA01

Claims (4)

[Claims] 1. An image reading apparatus which scans an original and reads an image by an optical system having an optical mirror, wherein the optical mirror is fixed to at least two adjacent surfaces along a longitudinal direction of the optical mirror to reinforce the optical mirror. An image reading device comprising a reinforcing member. 2. The image reading apparatus according to claim 1, wherein the reinforcing member is a sheet metal bent along a plurality of fixing surfaces with the optical mirror. 3. An optical member according to claim 1, wherein an elastic member is interposed between said reinforcing member and said optical mirror.
The image reading device according to claim 1. 4. The image reading apparatus according to claim 1, wherein the reinforcing member extends to near both ends in the longitudinal direction of the optical mirror.