JPH09325428A - Picture image reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a picture image reader which can prevent a mirror from becoming dirty by a simple configuration and prevent a rise of temperature in a picture image formation device. SOLUTION: This device is provided with a first running body 30 having a light source 11 which irradiates a face of manuscript 5 put on a contact glass 14 and a mirror 22, a second running body 31 provided with a second mirror 23 and a third mirror 24 for changing the direction of an optical path from the first running body, and an image formation lens 25. In this case, a shielding cover 315 which shuts off stray light from the circumference is provided on the image formation lens 25, seal members 316, 317 are provided in a peripheral fringe part which opposes to the second running body 31 of the shielding cover and/or a peripheral fringe part of the mirror which opposes to the shielding cover of the second running body 31, and the second running body 31 is moved into the direction of image formation lens to seal the third mirror 24 almost completely while the picture image reading device is in a stand-by condition.

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 used in an image forming apparatus such as a copying machine, a laser printer, and a facsimile, and more particularly to prevention of dirt on a mirror.

[0002]

2. Description of the Related Art An image reading apparatus is used in an image forming apparatus such as a copying machine, a laser printer, and a facsimile. The image reading apparatus usually includes a first running body and a second running body.
And a traveling body are provided. The first traveling body is composed of a light source that irradiates a document placed on the contact glass while scanning it, and a first mirror that reflects light reflected from the document surface. The second traveling body includes a second mirror on which the reflected light from the first mirror is incident and a third mirror arranged so as to be orthogonal to the second mirror. The direction of the light beam emitted from the mirror is reversed and the light beam is made incident on the imaging lens. In addition, the second traveling body,
It moves in the same direction as the first traveling body at a speed of 1/2.

With such a structure, in an image reading apparatus, if dust or dust adheres to the mirror surfaces of these mirrors, for example, in a copying machine, the exposure light amount on the surface of the photoconductor is reduced or unevenness occurs. There is a problem that the background of the image becomes dirty.

As a method for solving this problem, one is
There is a method of sealing the optical device to prevent dust and dirt from entering as much as possible. However, if it is hermetically closed, the temperature inside the machine rises too much, so it is necessary to provide a fan for cooling the inside of the machine and attach a dustproof filter to the outside air suction port.

As another method, a method of detecting the amount of exposure light and correcting the illuminance of the light source according to the degree of contamination of the mirror is adopted. However, with any of the above methods, it is difficult to suppress the temperature rise inside the optical device.

Therefore, as a reliable method capable of solving the problem of temperature rise and removing dirt on the mirror, Japanese Patent Laid-Open No. 4-31 is known.
In No. 5140, a member for cleaning the mirror is attached to the scanner, and a power transmission means for driving the cleaning member is provided on the optical device main body side, and when the scanner is in a standby state, they are connected to wipe the mirror. Such a configuration has been proposed.

[0007]

However, in the above method, the mirror cleaning member, the driving means therefor, and the drive transmission means are required, and the apparatus becomes large and complicated, and the manufacturing cost increases. There was a problem.

The present invention has been made to solve the above problems, and an object of the present invention is to provide an image reading apparatus capable of preventing the mirror from being soiled with a simple structure.

[0009]

In order to achieve the above object, the present invention provides a first traveling body having a light source and a mirror for illuminating an original surface placed on a contact glass, and a first traveling body. A second moving body having a mirror for changing the direction of the optical path from the first traveling body and moving at a speed half that of the first traveling body;
In an image reading apparatus including a running body and an imaging lens, the imaging lens is provided with a light blocking cover for blocking stray light from the surroundings, and a peripheral portion of the light blocking cover facing the second running body and / or the above. A seal member is provided on the peripheral edge of the mirror of the second traveling body facing the light-shielding cover, and the second traveling body is moved in the direction of the image forming lens while the image reading device is on standby to substantially seal the reflecting surface of the mirror. It is characterized by doing so.

Further, the second traveling body makes an obliquely downward second mirror that reflects the incident light from the first traveling body, and the reflected light from the second mirror enters and directs it toward the imaging lens. It may be configured such that it has a third mirror that is obliquely upwardly reflected and that the sealing member seals the third mirror.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram showing the overall configuration of a copying machine exemplified as an image forming apparatus. In the figure, the copying machine main body 1 is internally partitioned by a partition plate 2 into an upper chamber 3 and a lower chamber 4, a contact glass 14 on which an original 5 is placed, and an optical system 6 for exposure scanning. Is provided,
In the lower chamber 4, a copy processing section 8 for forming a copy image on the copy paper 7 and a copy paper transport section 9 are provided.

Here, the optical system 6 includes a light source 11, an illuminating section 21 composed of a main reflecting plate 12 and an auxiliary reflecting plate 13, and a first reflecting unit.
It includes a mirror 22, a second mirror 23, a third mirror 24, a lens 25, and a fourth mirror 26. Of these, the illumination unit 21 and the first mirror 22 constitute the first traveling body 30,
The second mirror 23 and the third mirror 24 form a second traveling body 31. Then, these first and second traveling bodies 3
0 and 31 are moved in a direction indicated by an arrow A by a mechanism (not shown) so that the original 5 on the contact glass 14 can be exposed and scanned.

The first traveling body is set to move at twice the speed of the second traveling body, and the fourth mirror 26 is fixed.

The copy transport unit 9 includes a paper feed roller 91,
Paper feed guide plate 93, registration rollers 95, conveyor belt 9
6, a fixing roller 98, and a paper discharge roller 99. By driving the paper feed roller 91, the copy papers 7 are taken out one by one from the paper feed table 16 and guided to the copy processing section 8 to transfer a toner image. , Heating the toner image by the fixing roller 98,
After fixing, it is configured to be discharged onto the pedestal 18.

As the copy processing section 8, the charging charger 8 is provided around the photosensitive drum 81 which rotates in the direction indicated by C in the figure.
2, eraser 83, developing device 84, transfer charger 8
5, a separation charger 86, and a cleaning device 87 are arranged in this order, and a document image is formed on the outer surface of the photosensitive drum 81 uniformly charged by the charging charger 82, and a peripheral edge where an electrostatic latent image is not formed. After removing the electrostatic charge of the portion by the eraser 83, the developing device 84 visualizes the toner image, the transfer charger 85 transfers the toner image onto the copy paper 7, and the residual toner is removed by the cleaning device 8.
Collect at 7.

2 to 4 are views showing an embodiment of the present invention. In these figures, the second traveling body 31 has
The second mirror 23 and the third mirror 24 are mirror support plates 311.
It is pressed against the plate spring 312 with respect to, and is arranged and fixed so that these reflecting surfaces form an angle of 90 °.

The second traveling body 31 is provided with some slide shoes 313 at both ends thereof, and by mounting it on a rail 314 arranged in a stationary portion in the optical device, the direction shown by the arrow in FIG. It is possible to move for scanning. Although not shown in the figure, the driving means necessary for the movement for this scanning is configured such that a wire, a belt or the like is connected to both ends of the running body, and is wound and rewound by a pulley attached to a motor.

The reflected light image of the original is reflected by the second mirror 23 and the third mirror 24 as indicated by the arrow in FIG.
The light is turned in the direction of ° and enters the imaging lens 25 (Fig. 1).

A light blocking member is provided around the image forming lens 25 and the image forming light beam to the photosensitive drum 81 so that flare light other than the image forming light beam does not enter. That is, the upper and front and rear side surfaces of the imaging lens 25 are shielded by the light shielding cover 315, and the surface on the side where light is incident may be shielded by a member integrated with the light shielding cover 315 by opening only the incident portion of the lens. Good. In the illustrated embodiment, the variable power optical system is illustrated, but in the case of the variable power optical system, the light shielding cover 31 of this embodiment is used.
Instead of adopting No. 5, a light shielding cover that moves integrally with the imaging lens 25 may be provided.

In the present invention, a seal member 316 made of an elastic material such as polyurethane foam is attached around the surface of the light-shielding cover 315 on the light incident side. The lower surface is
For example, the seal member 317 is provided on the lens bracket 318 to which the imaging lens 25 is fixed.

During the reading scan standby, the second traveling body 31 is moved toward the imaging lens 25, and is controlled until the third mirror 24 comes into contact with the seal members 316 and 317. As a result, the surface of the third mirror 24 and the surface of the imaging lens on the incident side are almost sealed, and it is possible to prevent dust and dirt from adhering to the surface.

The fourth mirror 26 behind the imaging lens 25 and the exit side surface of the imaging lens 25 have a light blocking cover 31.
As it is covered with 5, it is hard to get dirty. Further, the light shielding cover 315 may have a shape that covers both the second mirror 23 and the third mirror 24. However, the mirror facing up is more likely to get dirty due to dust, dust, etc. than the mirror facing down, so even if only the third mirror 24 is provided with a stain prevention measure, the intended purpose is Can be achieved. This is because the second mirror faces downward, so that dirt hardly poses a problem.

In FIG. 4, the seal member 318 is attached to the third mirror 2.
It shows an embodiment attached to the 4 side. In this way, the seal member is provided on the third mirror 24 side and the light shielding cover 3
It may be provided on any of the 15 sides, or on both sides.

[0024]

According to the present invention as described above,
Only a few sealing members need to be added to the current device, and it is not necessary to provide a cleaning member or its drive device or power transmission device as in the conventional device, so a simple configuration will be sufficient and cost will be reduced. The effect on up is small. Also, because it shields only during the read scan standby, there is no problem of heating,
There is no need to add a cooling device.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an overall configuration of a copying machine exemplified as an image forming apparatus of the present invention.

FIG. 2 is a cross-sectional view of essential parts showing a dustproof structure of the image reading apparatus of the present invention.

FIG. 3 is a perspective view of essential parts showing a dustproof structure of the image reading apparatus of the present invention.

FIG. 4 is a main part perspective view showing another embodiment of the image reading apparatus of the present invention.

[Explanation of symbols]

 5 Original Document 11 Light Source 14 Contact Glass 22 Mirror 23 Second Mirror 24 Third Mirror 25 Imaging Lens 30 First Traveling Body 31 Second Traveling Body 315 Light-Shielding Cover 316 Sealing Member 317 Sealing Member 318 Sealing Member

Claims (2)

[Claims] 1. A first traveling body having a light source for illuminating a document surface placed on a contact glass and a mirror, and a mirror for changing an optical path direction from the first traveling body. Second moving at half the speed of one running body
In an image reading apparatus including a traveling body and an imaging lens, the imaging lens is provided with a light-shielding cover that blocks stray light from the surroundings, and the peripheral portion of the light-shielding cover facing the second traveling body and / or the above A seal member is provided on the periphery of the mirror of the second traveling body that faces the light-shielding cover, and the second traveling body is moved in the direction of the imaging lens while the image reading device is on standby to substantially seal the reflecting surface of the mirror. An image reading device characterized by the above. 2. The second traveling body comprises a second mirror which is inclined downward and reflects incident light from the first traveling body, and the second traveling body.
A third mirror, which is obliquely upward and reflects reflected light from a mirror and reflects the light toward the imaging lens, and the seal member seals the third mirror. 1. The image reading device described in 1.