JPH0229613A - Optical scanning device - Google Patents

Abstract

PURPOSE:To prevent dust from going into the periphery of a rotary polygon mirror at the time of assembling a device by forming the vicinity of a deflecting means by a dustproof structure. CONSTITUTION:A cover 11 consists of a fixed part 11a for covering a rotary polygon mirror, etc., and a movable part 11b for covering a beam detector 9, etc. This fixed part 11a overhangs to the vicinity of about a lens 5, and fixed to the upper face of an optical frame 20 with no gap. Also, in a position which is the lower face of the fixed part 11a and corresponds to the lens 5, a rectangular dustproof member 13 which protrudes downward and abuts on or placed adjacently to the lens 5 is provided, and by these dustproof member 13 and lens 5, a dustproof means is constituted. Accordingly, it does not occur that dust in an atmosphere intrudes into the periphery of the rotary polygon mirror 3.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a scanning optical device equipped with a deflection means for scanning a light beam such as a laser beam onto a photoreceptor, a display, an article to be inspected, and the like.

(Prior Art) Conventionally, in an apparatus in which a light beam emitted from a light source such as a semiconductor laser is scanned by a rotating polygon mirror, and an image is formed and scanned on a scanned object such as a photoreceptor through an imaging lens. Since the rotating polygon mirror is rotated at high speed by a drive motor, there is a problem in that floating dust in the atmosphere adheres to the mirror surface of the rotating polygon mirror, thereby reducing its reflectance.

This phenomenon causes a decrease in the power of the light beam on the scanned object such as a photoreceptor, resulting in a decrease in the density of the output image in recording devices, display devices, etc., and a decrease in detection accuracy in inspection devices, etc. It appears as.

Therefore, in order to prevent dust in the atmosphere from adhering to the rotating polygon mirror, in the past, the scanning optical device equipped with the rotating polygon mirror was assembled in a highly clean place with little dust. The rotating polygon mirror was protected by sealing it or by providing a dustproof member on the scanning optical device.

(Problem to be Solved by the Invention) Incidentally, in an image recording device using this type of device, a device for obtaining horizontal synchronization of images (hereinafter referred to as a beam detector) is generally disposed within the scanning optical device. , has a configuration in which signals obtained from this beam detector are sent to a controller unit located outside the scanning optical device.

Therefore, in the case of such a conventional example, a member such as a cord is required to connect the beam detector inside the scanning optical device and the controller unit outside the device, and furthermore, when the scanning optical device is installed in the image recording device, It is necessary to remove the dustproof cover covering the frame of the scanning optical device and connect the cord. For this reason, there is a problem in that dust may enter the vicinity of the rotating polygon mirror during assembly of the device, and as a result, the mirror surface of the rotating polygon mirror becomes dirty and the reflectance decreases.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and its purpose is to provide a scanning optical device that can prevent dust from entering around the rotating polygon mirror when assembling the device. It is about providing.

(Means for Solving the Problems) In order to achieve the above object, the present invention includes a light source that generates a light beam, a deflection means for deflecting and scanning the light beam onto a surface to be scanned, and a light source that generates a light beam. In a scanning optical device comprising a lens group for condensing a light beam from a deflection means and a horizontal synchronization detection means for detecting horizontal synchronization of the light beam from the lens group, the vicinity of the deflection means has a dust-proof structure. The present invention is characterized in that it is provided with a dustproof means, and further includes a lid that can be opened and closed to expose at least the horizontal synchronization means other than the dustproof part.

(Function) In the present invention having the above configuration, when the present invention is incorporated into an image recording device or the like, the horizontal synchronization means is exposed by opening the openable/closable lid provided other than the dustproof part, and the horizontal synchronization means and the control unit In this case, since the vicinity of the deflection means has a dust-proof structure with dust-proof means, dust in the atmosphere will not enter the vicinity of the deflection means.

(Example) Hereinafter, the present invention will be explained based on illustrated embodiments.

1 and 2 show an embodiment of a scanning optical device according to the present invention, and FIG. 3 shows a cross section of an image recording device using electrophotography to which the embodiment is applied. It is.

In this scanning optical device S, an optical frame 20 accommodating each member is positioned by fitting onto the upper part of the printer main body as shown in FIG. 3, or after the position is adjusted, it is fixed with screws 15 or the like.

As shown in FIG. 1, the scanning optical device S has a semiconductor laser 1 as a light source. An imaging lens 2 which is deflected and scanned by 3 and further has an fθ characteristic etc. and constitutes a condensing lens group.
, 4, 5, the light is irradiated onto a photosensitive drum 7 as a surface to be scanned via a folding mirror 6, and an electrostatic latent image is formed on the drum 7. This electrostatic latent image is visualized in a process cartridge 21 equipped with a wide charger, a developer, a cleaner, etc., and transferred to a transfer material 23 such as paper by a transfer body electric device 22, and then transferred to a fixing device 27. The image is fixed on the transfer material 23 by the transfer material 23, and finally the transfer material 23 is discharged out of the apparatus.

Here, the transfer materials 23 are stacked in a paper feed cassette 24, and are fed out one by one by a paper feed roller 25. Further, reference numeral 26 denotes a registration roller for timing the transfer between the transfer material 23 and the image on the photosensitive drum 7.

By the way, in this type of image recording device, the rotating polygon mirror that scans the light beam in the axial direction of the photosensitive drum has surface division errors on each mirror surface, so it does not always start writing the image from a fixed position. Image distortion may occur.

Therefore, in this type of apparatus, a beam detector 9 as horizontal synchronization means as shown in FIG. 1 is provided in order to detect and adjust the timing of modulating the light beam for each scan.

In this case, the beam detector will be installed in the non-image area on the image writing side and at the focal point of the light beam, but this will prevent the device from becoming larger and require fine adjustment of the light beam. Therefore, in this embodiment, mirror 1
The light beam is folded back at the optical frame 20, and the light beam is detected by a beam detector 9 disposed within the optical frame 20. An optical fiber 12 is connected to this beam detector 9, and the light beam is transmitted to a controller unit 30 having a photoelectric conversion element such as a PIN photodiode.

By the way, this optical fiber 12 needs to be connected to the scanning optical device S and the controller unit 30 when the scanning optical device S is attached to the printer body, but the unit 30 is connected to the printer body as shown in FIG. If the device is configured to be housed in the bottom box 28 at the bottom, it is difficult to connect the optical fiber 12 to the controller unit 30 after the printer main body is almost assembled. Therefore,
Normally, when assembling the device, the lid of the optical frame 20 is opened and the optical fiber 12 is attached to the scanning optical device S side. However, in that case, as described above, there is a problem in that dust in the atmosphere enters the area around the rotating polygon mirror 3 and the mirror surface becomes dirty.

Therefore, in this embodiment, the lid 1 as shown in FIG.
1 to solve this problem. That is, as shown in the figure, the lid 11 includes a fixed part 11a for covering the rotating polygon mirror 3 and the like, and a movable part 11b for covering the beam detector 9 and the like. This fixing portion 11a protrudes almost to the vicinity of the lens 5, and is fixed to the upper surface of the optical frame 20 without leaving a gap. And fixed part 1
A rectangular dustproof member 13 that protrudes downward and contacts or is close to the lens 5 is provided on the lower surface of 1a at a position corresponding to the lens 5, and the dustproof member 13 and the lens 5 constitute a dustproof means. There is. Therefore, dust in the atmosphere does not enter the area around the rotating polygon mirror 3.

The movable part 11b is rotatably supported in the direction of arrow A or B at a hinge part 14 closer to the beam detector 9 than the dustproof member 13, and can be opened and closed. A presser foot 1 for fixing the optical fiber is provided on the lower surface of the movable part 11b.
8 is for installation. This is due to the following reasons.

That is, the tip of the optical fiber 12 is provided with a tip sleeve 121 having a convex portion as shown in FIG. It is fixed to a fixing member 90 having a. In this case, since the optical frame 20 has a large hole for the distal end sleeve 121 to pass through (200 in FIG. 200
As a result, the optical fiber 12 may obstruct the optical path of the light beam, and the horizontal synchronization signal may also be slightly affected, disturbing the image.

Therefore, in this embodiment, a presser foot 18 for fixing the optical fiber 12 is provided on the movable portion 11b of the lid 11 to restrict the movement of the optical fiber 12.

Note that a hook 17 that engages with a hook 16 provided on the optical unit 20 is provided on the edge of the movable portion 11b.
b can be held in a closed state.

In this embodiment having the above configuration and operation, the movable part 11b near the optical fiber 12 can be opened and closed while the area around the rotating polygon mirror 3 remains dust-proof. The optical fiber 12 can be attached to the beam detector 9 even after being mounted on the beam detector 9, and since the optical fiber 12 does not move and the image is not disturbed, there is an excellent effect that a high-quality image can always be obtained.

Furthermore, the mirror 10 that guides the light beam to the beam detector 9 requires very delicate adjustment, and if even the slightest positional deviation occurs, the image will not be recorded at the desired position. 3. Since the surrounding area is dust-proof, even if the position of the mirror 10 is shifted due to vibration or falling when the movable part 11b of the lid 11 is opened or closed, it will not affect other members such as the rotating polygon mirror 3. Another advantage is that adjustments can be made without any hassle.

Furthermore, in this embodiment, the dustproof member 13 is attached to the lens 5.
Since it is provided above the lens group 2.4.5, it is also possible to protect the lens group 2.4.5 from dust, and it is possible to prevent a decrease in the light intensity of the light beam passing through the lens.

(Other Examples) The scanning optical device includes a laser light source and a drive motor for the rotating polygon mirror, but since the modulation of the semiconductor laser and the control of the drive motor are also performed by the controller unit, the connection of these devices is difficult. If the rotating polygon mirror is disposed within an optical frame, the problem of dust adhering to the mirror surface of the rotating polygon mirror may occur as in the case described above. Therefore, in the past, the above-mentioned connection part was placed outside the scanning optical device, but for example, the fifth
In a scanning optical device that requires two laser light sources arranged side by side as shown in the figure, it is also necessary to have a connection portion for the laser light source within the scanning optical device. Especially when the lifespan of the semiconductor laser is short compared to the main body of the image recording device, or when it breaks down,
It may be necessary to replace the laser light source during use of the image recording device.

Therefore, in this embodiment, one laser light source 100
is positioned with respect to the optical frame 20 by fitting and is attached with a screw lot, and around it, the optical frame 20 is attached by a part 110 and a movable lid! Efforts have been made to minimize the gap where dust can enter when the IC is in contact with or in close proximity to the IC. Furthermore, the mounting portion 110 has a small hole 11 through which the light beam emitted from the other laser light source 1 passes, and a similar small hole 11 through which the light beam emitted from one laser light source 100 passes. Even when a hole (not shown) is opened and the laser light source 100 is replaced, the movable lid 11C can be opened as shown by the arrow in the figure by the hinge 140 located outside the dustproof part. Even if the laser light source 100 is removed, the structure prevents dust from entering around the rotating polygon mirror.

In the configuration shown in FIG. 5, it is more preferable to provide a dustproof glass or the like for shielding instead of making a small hole.

In each of the embodiments of the present invention, the lid is provided with a hinge so that it can be opened and closed, but the same applies even if the lid is divided into multiple parts or is opened and closed by a sliding type. The effect of this can be obtained.

(Effects of the Invention) As explained above, in the present invention, the vicinity of the deflection means for deflecting and scanning the light beam is provided with a dust-proof structure, and a lid that can be opened and closed is provided in addition to the dust-proof part, so that at least the horizontal synchronization means This allows for the exchange of parts inside the device and the removal of signal transmission members such as cords in the horizontal synchronization means, etc., while preventing dust in the atmosphere from entering the vicinity of the deflection means. This has the effect of preventing a decrease in reflectance due to dirt on the mirror surface of the deflection member.

In this case, if the dustproof means is configured together with the optical frame, cover, lens, etc. of the device, manufacturing costs will hardly increase and assembly workability can be improved.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an embodiment of the scanning optical device according to the present invention, FIG. 2 is a perspective view showing the device shown in FIG. 1 with the movable part of the lid open, and FIG. A fourth vertical cross-sectional view showing a schematic configuration of an image recording device to which such a scanning optical device is applied.
This figure is an enlarged plan view showing the tip sleeve of the optical fiber and the beam detector, and FIG. 5 is an enlarged perspective view showing the laser light source mounting section in another embodiment of the present invention. Explanation of symbols 1... Semiconductor laser light source (light source) 3... Rotating polygon mirror (deflection means) 2.4.5... Imaging lens (lens group) 7.
...Photosensitive drum (scanned surface) 9...Beam detector (horizontal synchronization detection means) 11.
... Lid, 11a... Fixed part, 11b... Movable part 12
...Optical fiber 13...Dust-proof member 14...Hinge Patent applicant Canon Co., Ltd. Figure 4

Claims (3)

[Claims] (1) A light source that generates a light beam, a deflection means for deflecting and scanning the light beam onto a surface to be scanned, a lens group that focuses the light beam from the deflection means, and a light beam from the lens group. In a scanning optical device equipped with a horizontal synchronization detection means for detecting horizontal synchronization of a beam, a dustproof means is provided to provide a dustproof structure near the deflection means, and at least the horizontal synchronization means is exposed outside the dustproof part. A scanning optical device characterized by comprising a lid that can be opened and closed as freely as possible. (2) The scanning optical device according to claim 1, wherein the dustproof means includes the lens group. (3) The scanning optical device according to claim 1 or 2, further comprising a regulating member that regulates a movable member inside the lid according to opening and closing of the lid.