JP5094898B2 - Optical scanning device, image forming device - Google Patents

Description

  The present invention relates to an optical scanning device mounted on an image forming apparatus using electrophotographic technology, such as a copying machine, a printer, a facsimile machine, or a multifunction machine having these functions.

As such an optical scanning device, in order to realize a reduction in size and height, a light beam from a semiconductor laser, for example, a light source disposed on one side of a base provided inside the housing is deflected by an optical deflector. Some are configured to scan, pass through an imaging lens or the like, and pass through an opening (hole) of the base by a folding mirror to be guided to the other side (opposite side) of the base.
In the apparatus configured as described above, on one side of the substrate, the light beam from the light source is deflected and scanned by the optical deflector, and the deflected and scanned beam passes through the first imaging lens and is further reflected by the first folding mirror. There is an optical writing device configured to be folded and pass through the opening of the substrate and guided to the other surface side of the substrate (see, for example, Patent Document 1).

  The opening of the substrate in the optical writing device is a slit (scanning direction hole) that opens in accordance with the range through which the deflection-scanned light beam passes, and is formed in the substrate along the mirror in the vicinity of the first folding mirror. Has been.

JP 2002-148542 A

  As in the invention described in Patent Document 1, when an opening is formed in the base for guiding light rays from one side of the base to the other side, the strength of the base decreases, so internal stress or force applied from the outside In some cases, the housing integrated with the base or the substrate may be deformed. When the base is deformed, an optical system including an optical deflector, a first imaging lens, a first folding mirror, and the like arranged on one side of the base, and a second arranged on the other side of the base. The optical path in each optical system with the optical system composed of the imaging lens, the second folding mirror, etc. is out of order, or the optical path connecting both optical systems is out of order. Further, when the strength of the base is lowered, the rigidity of the base is lowered, and the substrate is likely to be deformed by vibration by a polygon motor or the like that rotationally drives the polygon mirror of the optical deflector. Due to these factors, there arises a problem that image quality deteriorates due to generation of a jitter image.

  The present invention has been made paying attention to such a problem, and the light beam after being deflected and scanned from the light source is guided from one side of the base to the other side of the base through the opening formed in the base. It is an object of the present invention to provide an optical scanning device that can sufficiently ensure the strength of the substrate even in the case of being present.

In order to solve the above-described problems, an optical scanning device of the present invention includes a base, a light source that is disposed on one side of the base, emits a light beam including image information in part, and a side on which the light source of the base is provided. An optical deflector that deflects and scans a light beam from the light source in a predetermined angle range, and a light beam deflected and scanned by the optical deflector through the scanning direction hole formed in the substrate. an optical system for guiding folded to the side, provided on the other side of the foundation, is the deflection scanning, scanning start for detecting the scanning start position detection area that does not include the image information of the light beam having passed through the scanning direction hole In the optical scanning device provided with the position detection region detection means, a long portion through which the light beam in the region including the image information of the scanning direction hole passes and a short portion through which the light beam in the scanning start position detection region passes. , separation forming part of the foundation It is configured as an optical scanning device in which are formed and separated by.

In the present invention, the scanning direction hole corresponding to the opening is formed and separated by the separation wall which forms part of the foundation. That is, since the scanning direction holes are connected by the separating wall in the middle, the separation wall to ensure the strength of the foundation. Therefore, the strength of the base is sufficiently ensured as compared with the case where the scanning direction hole is one continuous hole.
The present invention is, as in the embodiment described later, one side of the foundation even if (in the embodiment the upper side) there is a light source, the other surface side of the base plate in the opposite (lower side in the embodiment) Needless to say, the present invention can be applied even when there is a light source.
In a more preferred form, the optical path of the light beam deflected and scanned by the optical deflector passes through a portion of the scanning direction hole through which the light beam in the region including the image information passes from the surface side on which the light source is disposed. Then, an optical scanning device configured to be folded back to the side opposite to the surface side on which the light source is disposed, and further to the surface side on which the light source of the base is disposed can be considered.
In the present invention, the image forming apparatus includes a copying machine, a printer, a facsimile, or a multifunction machine having these functions using electrophotographic technology.

  According to the present invention, since the strength of the base can be sufficiently secured, the base is not only strong against deformation due to external force or internal stress, but also strong against vibration caused by a vibration source such as a polygon motor. Become. As a result, it is possible to prevent the occurrence of jitter images and to improve the image quality.

It is an external appearance perspective view from one angle which shows the base upper side in the state which removed the upper cover of the optical scanning device concerning an embodiment. It is an external appearance perspective view from another angle which shows the base upper side in the state which removed the upper cover of the same optical scanning device. FIG. 3 is a schematic enlarged sectional view taken along line AA in FIG. 2. It is a schematic plane explanatory drawing which shows the characteristic part of the same optical scanning device. It is a schematic plane explanatory drawing which shows the characteristic part of the optical scanning device which concerns on a prior art example.

Hereinafter, the present invention will be described in more detail with reference to embodiments.
As described above, the optical scanning device shown in FIGS. 1 to 3 is mounted on a copying machine, a printer, a facsimile, or a multifunction machine having these functions using electrophotographic technology.

In this optical scanning device, each light beam from two light sources (for example, semiconductor lasers) is deflected and scanned in two symmetrical directions by an optical deflector. In this optical scanning device, a horizontal base 2 provided inside the casing 1 is arranged so as to partition the internal space of the casing 1 into two spaces on one side and the other side of the base 2. In the following, for convenience, one side of the base 2 is referred to as the upper side, and the other side is referred to as the lower side.
The two light sources 10 and 11 are attached in the vicinity of the side wall of the housing 1 so that each light beam emitted from the light sources 10 and 11 is directed to the optical deflector 15 attached to the base plate 2 at substantially the center inside the housing 1. Further, the mounting angles of the light sources 10 and 11 are adjusted.
The light rays emitted from the light sources 10 and 11 include image information in a part thereof. Hereinafter, an area including image information in the light beam is referred to as an image area. In the image forming apparatus provided with the optical scanning device, a part of the light beam excluding the image region in the light beam deflected and scanned by the optical deflector 15 is detected, and scanning by the optical deflector 15 is started. Set the position. The light ray region corresponding to the light scanning position as described above is hereinafter referred to as a scanning start position detection region.

The optical deflector 15 distributes the light rays from the light sources 10 and 11 in two symmetrical directions as the light rays including the light rays in the image area and the scanning start position detection area, and deflects and scans them in a predetermined angle range. A polygonal polygon mirror 16 is provided, and the polygon mirror 16 is rotationally driven by a polygon motor (not shown).
An fθ lens 20 composed of a first lens 21 and a second lens 22 and an fθ lens 25 composed of a first lens 26 and a second lens 27 are disposed in each optical path of the light beam deflected and scanned in two directions. The first lenses 21 and 26 are located on the optical deflector 15 side, and the second lenses 22 and 27 are located on the first folding mirrors 30 and 31 described later.

The first folding mirrors 30 and 31 are arranged along the side wall of the housing 1 outside the second lenses 22 and 27. The first folding mirrors 30 and 31 reflect the light beam that has passed through the fθ lenses 20 and 25 to the lower side of the substrate 2, so that the first scanning direction hole is provided below the first folding mirrors 30 and 31. 40 and 45 are formed.
The first scanning direction holes 40 and 45 are the long portions 41 and 46 through which the light beams of the image region pass among the light beams deflected and scanned within a predetermined angle range by the optical deflector 15 and the scanning start position detection region. Short portions 42 and 47 through which the light passes are formed by separation walls 2 </ b> A and 2 </ b> B that form part of the base 2. That is, the two portions 41, 42 and 46, 47 are not continuous as one hole, but there are separation walls 2A, 2B integral with the base 2 between the two portions 41, 42 and 46, 47. Will do. However, the separation wall 2B does not appear in the drawing.

  The light sources 10 and 11, the optical deflector 15, the fθ lenses 20 and 25, and the first folding mirrors 30 and 31 are disposed on the upper side of the base 2. On the lower side of the base 2, as shown in FIG. In addition, second folding mirrors 32 and 33 are disposed below the first scanning direction holes 41 and 46. The second folding mirrors 32 and 33 reflect the light beam reflected by the first folding mirrors 30 and 31 to the lower side of the substrate 2 and passed through the first scanning direction holes 41 and 46 in a direction parallel to the lower surface of the substrate 2. Is.

  Further, on the lower side of the substrate 2, a third light beam reflected by the second folding mirrors 32 and 33 is reflected toward a scanned body (for example, a photosensitive drum, not shown) provided on the upper side of the substrate 2. Folding mirrors 34 and 35 are arranged. Correspondingly, the substrate 2 is formed with second scanning direction holes 50 and 51 on the upper side of the third folding mirrors 34 and 35 for transmitting light rays to the upper side of the substrate 2. The light beams reflected by the third folding mirrors 34 and 35 pass through the second scanning direction holes 50 and 51, respectively, and travel in the same direction toward the scanned body. The angle of 35 is adjusted.

  Although not shown in the drawing, the light beam in the scanning start position detection region that has passed through the short portions 42 and 47 of the first scanning direction holes 40 and 45 is arranged on the lower side of the base board 2 and reaches the scanning start position. The light is reflected by a scanning start position detection mirror (not shown) for taking out a light beam and received by a scanning start position detection sensor 60 (see FIG. 4). Based on the light reception signal from the sensor 60, the rotation of the optical deflector 15 is controlled with reference to the scanning start position, so that the image area passing through the long portions 41, 46 of the first scanning direction holes 40, 45 is controlled. The positional deviation of the light beam is corrected.

The optical scanning device configured as described above is configured to divide the optical paths of the light beams distributed in two directions, as described above, for the purpose of reducing the size and height of the device. By folding back from the upper side of the base board 2 to the lower side of the base board 2 by the mirrors 30, 32, 34 and 31, 33, 35 respectively, and further from the lower side of the base board 2 to the upper side of the base board 2, the optical path length can be set within a certain range. It is configured to fit in.
However, a scanning start position detection mirror (not shown) may be arranged on the upper side of the base 2 so that the optical path of the light beam in the scanning start position detection area is not guided to the lower side of the base 2 but only on the front side of the base 2. However, if the polygon mirror 16 is reduced in size, the light path of the light beam in the image area and the light path of the light beam in the scanning start position detection area become close to each other. For this reason, in order to separate the optical path of the light beam in the image area from the optical path of the light beam in the scanning start position detection area, the scanning start position detection mirror cannot be installed unless a certain distance from the polygon mirror 16 is placed. Therefore, it is convenient to arrange the scanning start position detection mirror below the base 2.

In this optical scanning device, as described above, the first scanning direction holes 40 and 45 have the long portions 41 and 46 through which the light rays in the image region pass and the short portions 42 and 47 through which the light rays in the scanning start position detection region pass. Is separated into two parts by separation walls 2A and 2B which are part of the housing 1 (see FIG. 4 showing only the first scanning direction hole 40).
There are separation walls 2A, 2B that divide the two parts 41, 42 and 46, 47. Since the separation walls 2A, 2B are integrated with the housing 1 (part of the housing), the two parts 41 , 42 and 46, 47 are one continuous hole (see FIG. 5 showing only the first scanning direction hole 40), the strength of the substrate 2 is sufficiently secured.

As described above, since the strength of the base 2 can be sufficiently secured, the base 2 is not only strong against deformation due to external force or internal stress, but also strong against vibration caused by a vibration source such as a polygon motor. Become. As a result, it is possible to prevent the occurrence of jitter images and to improve the image quality.
In particular, in this embodiment, since the first folding mirrors 30 and 31 and the second folding mirrors 32 and 33 and the first scanning direction holes 40 and 45 are very close to each other, the first scanning direction hole 40 is used. , 45 are likely to affect the strength of the support portions of the first folding mirrors 30, 31 and the second folding mirrors 32, 33. For this reason, the significance of the increase in strength due to the fact that the long portions 41, 46 of the first scanning direction holes 40, 45 and the short portions 42, 47 are connected by the separation walls 2A, 2B is significant.

DESCRIPTION OF SYMBOLS 1 Housing | casing 2 Base | substrate 2A, 2B Separation wall 10,11 Light source 15 Optical deflector 16 Polygon mirror 20, 25 f (theta) lens 30,31 1st folding | returning mirror 40,45 1st scanning direction hole 41,46 Long part 42,47 Short part

Claims (3)

The base,
A light source that is disposed on one side of the substrate and emits a light beam including image information in part;
An optical deflector that is provided on a side of the base on which the light source is provided, and deflects and scans a light beam from the light source in a predetermined angle range;
An optical system for guiding the light beam deflected and scanned by the optical deflector by folding it back to the other surface side of the base through a scanning direction hole formed in the base;
Provided on the other side of the foundation, it is the deflection scanning, and a scanning start position detecting area detection means for detecting the scanning start position detection area that does not include the image information of the light beam having passed through the scanning direction hole In an optical scanning device,
An elongated portion light of a region including the image information of the scanning direction hole passes, the short portion light of the scanning start position detection area to pass through, separated by a separation wall which forms part of the foundation An optical scanning device formed by   The optical path of the light beam deflected and scanned by the optical deflector is disposed through the portion of the scanning direction hole through which the light beam in the region including the image information passes from the surface side on which the light source is disposed. The optical scanning device according to claim 1, wherein the optical scanning device is configured to be folded back to the side opposite to the surface side and further folded back to the surface side on which the light source of the base is disposed.   An image forming apparatus comprising the optical scanning device according to claim 1.