JPH09243944A - Optical scanning device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform optical adjustment by moving a laser unit. SOLUTION: A laser unit 12 is engaged with a fitting hole 11a formed in an optical box 11, a semiconductor laser source 21 is fixed to a laser holder 22 of the laser unit 12 and a collimator lens 24 and anopical diaphragm 25 are arranged in a lens barrel 23. After adjusting the spot diameter of a laser beam forming the image on a photoreceptor drum so as to become small by parallely moving the laser unit 12 in the direction (a) of an arrow, the position C is coated with ultraviolet curing adhesive or the adhesive is poured into the fitting hole 11a from a pouring hole 11b and the unit is fixed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical scanning device for writing used in laser printers, digital copying machines, laser fax machines and the like.

[0002]

2. Description of the Related Art FIG. 5 shows an example of an optical scanning device used in a laser printer, a digital copying machine, a laser fax machine or the like. The luminous flux generated from the laser unit 1 including the semiconductor laser light source and the collimator lens is
It is linearly condensed by the cylindrical lens 2 and is irradiated on the reflecting surface 3 a of the rotary polygon mirror 3 which is composed of a plurality of mirror surfaces. Most of the light beam reflected by the reflecting surface 3a and deflected and scanned by the rotation of the rotary polygon mirror 3 is irradiated onto the reflecting mirror 5 through the scanning lens 4, and is reflected by the reflecting mirror 5 to reach a photosensitive drum (not shown).

The light flux reaching the photosensitive drum forms an electrostatic latent image on the photosensitive drum by the main scanning by the rotation of the rotary polygon mirror 3 and the sub-scanning by the rotation of the photosensitive drum. A part of the light beam deflected and scanned by the rotation of the rotary polygon mirror 3 reaches the synchronous sensor 7 by the reflecting mirror 6.

[0004]

However, in the above-mentioned conventional example, the focus adjustment of the light flux reaching the photosensitive drum is performed only by adjusting the distance between the semiconductor laser light source and the laser unit 1 by the laser unit alone. There is such a drawback. That is, the adjustment in the unit of the laser unit 1 requires the accuracy in the unit of μm, and the positional deviation at the time of fixing due to the adhesion or the like after the adjustment, the measurement error, etc. become a serious problem. Further, since the lens system in the optical box, the rotary polygon mirror 3 and the like are left unadjusted, a focus error is likely to occur on the photosensitive drum due to a positional error or the like.

The object of the present invention is to solve the above problems,
The adjustment accuracy required for the focus adjustment of the laser unit alone is lowered to facilitate the assembly, and the focus deviation on the photoconductor drum due to the position deviation of the lens system, the rotating polygon mirror, etc. in the optical box is corrected, It is an object of the present invention to provide a high-quality optical scanning device by reducing the spot size of a laser beam emitted onto a body drum.

[0006]

In order to achieve the above object, an optical scanning device according to the present invention comprises a light source unit comprising a laser light source and lens means for converting the light flux from the laser light source into a convergent light flux, and the convergent light flux. A light source unit, a deflecting means, and an optical box to which the scanning lens means is attached. A unit is attached to the optical box so as to be adjustable in the optical axis direction of the convergent light beam emitted from the lens means, and the light source unit is moved and adjusted in the optical axis direction so that the scanning lens means causes a predetermined surface to move. It is characterized in that the focus of the light beam scanned in is adjusted.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with reference to the embodiments shown in FIGS. 1 and 2 show a first embodiment, which has a semiconductor laser light source and a collimator lens, and is attached to an optical box 11 which is a laser unit 12.
The cylindrical lens 13 and the rotary polygon mirror 14 are sequentially arranged in the outgoing direction of the laser beam from the rotary polygon mirror 1.
A scanning lens 15, a reflecting mirror 16, and a photosensitive drum 17 are provided in the deflection scanning direction of No. 4. A part of the deflected and scanned laser beam is reflected by the synchronous mirror 18 and detected by the synchronous sensor 19.

When this device is assembled, first, the optical polygonal box 11, the rotary polygon mirror 14, the cylindrical lens 13,
The scanning lens 15 and the reflecting mirror 16 are attached. In addition, the laser unit 12 alone is used to complete focus adjustment and optical axis adjustment in advance by known techniques. However, the focus adjustment using only the laser unit 12 may be performed with lower accuracy than the conventionally required adjustment accuracy. This accuracy can be arbitrarily set according to the adjustment range of adjustment by moving the laser unit 12 described later, the optical arrangement, and the like.

Next, the laser unit 12 is attached to the optical box 11.
At this time, the laser beam is moved from the laser unit 12 in the optical axis direction of the arrow a while being generated. Since the laser light flux emitted from the laser unit 12 is a convergent light flux, the focus position of the laser light flux imaged on the photosensitive drum 17 moves back and forth in the direction of arrow b as the laser unit 12 moves.

Therefore, the focus position of the laser beam is observed at the position of the photoconductor drum 17, and when the focus position coincides with the surface of the photoconductor drum 17, an adhesive such as an ultraviolet curable type is applied to cure the laser unit. Fix 12 Further, the adhesive may be applied in advance. After that, the position of the cylindrical lens 13 and the angle of the synchronous mirror 7 are adjusted, but these adjustments may be omitted if unnecessary.

The laser unit 12 is fitted in a fitting hole 11a provided in the optical box 11 as shown in FIG. In the laser unit 12, the semiconductor laser light source 21 is fixed to a laser holder 22, and a lens barrel 23 is provided in front of the laser holder 22.
3, a collimator lens 24 and an optical diaphragm 25 are provided. Laser unit 12 or laser holder 2
After adjusting 2 by moving in parallel in the direction of the arrow a, an ultraviolet curing adhesive may be applied to the position C for fixing, or the adhesive may be injected from the injection hole 11b into the fitting hole 11a. Good.

With the above arrangement, the focus deviation of the laser beam on the photosensitive drum 17 due to the positional error of the rotary polygon mirror 14, the scanning lens 15 and the accuracy error of the optical box 11 can be greatly reduced. Since the spot diameter of the laser light flux imaged on the photosensitive drum 17 can be reduced, a high-definition recorded image can be obtained.

Further, as compared with the focus adjustment using the laser unit 12 alone, the focus adjustment with the above-described configuration can be performed easily because the accuracy is 1 or less, which is several tens of minutes.

The magnification relationship between the moving amount of the laser unit 12 and the moving amount of the focus position at the position of the photosensitive drum 17, the accuracy of the optical box 11, the rotary polygon mirror 14 and the scanning lens 1
If the position accuracy of 5 is set appropriately and the moving range of the laser unit 12 with respect to the optical box 11 is set to about several mm, the position adjusting and fixing mechanism of the laser unit 12 can be facilitated. This also applies to other embodiments described later.

FIG. 3 shows a second embodiment, in which the lateral wall of the optical box 11 is omitted. The laser holder 31 of the laser unit 12 is attached to a frame 32 by a known technique such as screwing, and the frame 32 is guided with respect to the optical box 11 so as to be movable in the optical axis direction of the arrow a of the laser unit 12. 33 is provided.

While moving the mount 32 to which the laser unit 12 is attached along the guide 33 in the direction of arrow a, the focus position of the laser beam at the position of the photosensitive drum 17 is observed and the focus adjustment is performed. After that, the pedestal 32 is fixed to the optical box 11 with the screw 34. Further, instead of the screw 34, an adhesive, a leaf spring or the like may be used for fixing.

Further, the laser unit 12 and the pedestal 32 may be integrated. With this configuration, the number of parts can be reduced, and the cost can be reduced.

As described above, in addition to the effects of the first embodiment, the optical box 11 of the laser unit 12 is provided.
Can be mounted from above. Optical box 11
As for the other parts to be attached to, most of the rotary polygon mirror 14, the cylindrical lens 13, the scanning lens 15,
Since the reflecting mirror 16 and the like are attached from above and the laser unit 12 is also attached from the same direction, it is possible to simplify the process, especially the automatic assembling machine.

FIG. 4 shows a third embodiment, in which the laser holder 41 of the laser unit 12 is fitted in a fitting hole 11a provided in the optical box 11. Semiconductor laser light source 2
Reference numeral 1 is fixed to a laser holder 41, and a lens barrel 23 is provided in front of the laser holder 41, and a lens barrel 23 is provided with a collimator lens 24 and an optical diaphragm 25. A nut 42 is screwed into the laser holder 41, a compression spring member 43 is inserted between the optical box 11 and the flange 41b of the laser holder 41, and the laser holder 41 is biased rearward.

When assembling this apparatus, first, the laser holder 41 and the lens barrel 23 are used to adjust the optical axis and focus of the semiconductor laser light source 21 and the collimator lens 24 by using a known technique.

Next, while turning on the semiconductor laser light source 21, by rotating the nut 42, the laser holder 41 is moved in the direction of the arrow a, and the focus position of the laser light flux imaged on the photosensitive drum 17 is adjusted. Observe and adjust the focus. When this adjustment is completed, the nut 17 is fixed with an adhesive or the like, and the laser holder 41 is fixed to the compression spring member 4
It is fixed to the optical box 11 by the spring force of 3 and the nut 17.

Further, the flange 41 of the laser holder 41
The laser holder 41 may be fixed by providing a screw portion on the a side and tightening the optical box 11 with nuts from both sides.

Further, a key groove may be provided in the optical box 11 and a key provided in the laser holder 41 may be fitted therein to prevent the laser holder 41 from rotating.

The first and third embodiments described above are the optical box 11
Since the cylindrical laser holder is fitted in, it is possible to significantly reduce the emission angle error of the converged light flux emitted from the laser unit. Further, since the airtightness of the optical box 11 can be enhanced, there is an effect that it is possible to prevent the lens system and the surface of the rotary polygon mirror from being contaminated due to the inflow of dust and toner.

[0025]

As described above, according to the optical scanning device of the present invention, when a laser unit having its focus adjusted and its optical axis adjusted by itself is attached to an optical box, its position is adjusted in the optical axis direction. By adjusting the focus of the laser light flux irradiated on the photosensitive drum, the following effects are produced.

(1) It is possible to reduce the adjustment accuracy of the focus adjustment of the laser unit alone, which has conventionally required very high accuracy, and the assembly becomes easy.

(2) It is possible to absorb an assembly error when a scanning lens, a rotary polygon mirror, etc. are attached to an optical box, and to greatly reduce a focus position error of a laser beam irradiated onto a photosensitive drum. You can

(3) Since the focus position error can be reduced even when the spot of the laser light flux irradiated on the photosensitive drum is reduced, a high-definition and high-quality recorded image can be provided.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an optical scanning device according to a first embodiment.

FIG. 2 is a cross-sectional view of a laser unit.

FIG. 3 is a perspective view of a laser unit according to a second embodiment.

FIG. 4 is a sectional view of a laser unit according to a third embodiment.

FIG. 5 is a configuration diagram of a conventional example.

[Explanation of symbols]

 11 Optical Box 12 Laser Unit 13 Cylindrical Lens 14 Rotating Polygonal Mirror 15 Scanning Lens 16 Reflecting Mirror 17 Photosensitive Drum 21 Semiconductor Laser Light Source 22, 31, 41 Laser Holder 23 Lens Barrel 24 Collimator Lens 25 Optical Aperture 32 Frame 33 Guide 42 Nut 43 Compression spring

Claims (2)

[Claims] 1. A light source unit comprising a laser light source and a lens means for converting a light flux from the laser light source into a convergent light flux, a deflecting means for deflecting the convergent light flux, and a light flux deflected by the deflecting means is scanned on a predetermined surface. In the optical scanning device having the scanning lens means for performing the light source unit, the deflection means, and the optical box to which the scanning lens means is attached, the optical axis of the convergent light beam emitted from the lens means with respect to the optical source box is provided. The optical scanning device is mounted so as to be adjustable in the direction, and the light source unit is moved and adjusted in the optical axis direction to adjust the focus of the light beam scanned on the predetermined surface by the scanning lens means. 2. The light source unit is adjustably attached to the optical box by using screw means or spring means.
3. The optical scanning device according to claim 1.