JPH04271316A - Optical scanner - Google Patents

Abstract

PURPOSE:To improve the rigidity of a casing by connecting 1st and 2nd base plate parts with a partition wall part and sorting and disposing optical members into two housing chambers formed in the casing. CONSTITUTION:The casing 10 has the 1st base plate part 11 and the 2nd base plate part 12 having a level difference therewith and has a curved sectional structure. The base plate parts 11, 12 are connected to each other by the partition wall part 13. The 1st housing chamber 16 delineated and formed by the 1st base plate part 11 and the partition wall part 13 and the 2nd housing chamber 17 delineated and formed by the 2nd base plate part 12 and the partition wall part 13 are formed. Further, the optical members, such as rotary polyhedral mirror 26 and toric lens 27, to be disposed in the casing 10 are disposed in the 1st base plate part 11 as :he cylindrical lens 24 and the rotary polyhedral mirror 26, etc., exist in the 1st housing chamber 16. The toric lens 27, ftheta mirror 28 and turn back mirror 29, etc., exist in the 2nd housing chamber 17 and are disposed in the 2nd plate part 12. These optical members are thus sorted and disposed in the two housing chambers 16, 17.

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 in which a light beam from a light source is scanned onto an object to be scanned using a polygon mirror, and in particular, the present invention relates to an optical scanning device that uses a polygonal mirror to scan a light beam from a light source onto an object to be scanned. The present invention relates to an optical scanning device.

0002

2. Description of the Related Art An optical scanning device for writing image information on recording paper by scanning a light beam from a light source with a rotating polygon mirror and irradiating it onto a photoreceptor has been developed in Japanese Patent Laid-Open No. 64-820.
There is one as shown in Publication No. 09. In this device, all optical members from a light source that emits a light beam to an imaging lens that directs this light beam toward a photoreceptor are housed in a casing that includes an optical box and a cover. . Since the photoreceptor is placed outside the casing, it is necessary to form an exit opening in either the optical box or the cover of the casing in order to irradiate the photoreceptor with the scanning light from the imaging lens. There is.

0003

[Problem to be Solved by the Invention] This exit aperture must be set to a length corresponding to the length in the main scanning direction of the light beam that scans the photoreceptor in the axial direction. Since it is formed near the photoreceptor, it is necessary to make the exit opening have a considerable length close to the axial length of the photoreceptor. Therefore, if an exit opening with a considerable length were to be formed in an optical box or cover, each of which is substantially flat, the rigidity of the entire casing would not be sufficient. If sufficient rigidity is not obtained,
Due to an increase in internal temperature due to heat generated from optical members within the casing, there is a risk that the casing may be distorted or the optical path of the light beam may be shifted. When such distortion occurs, there is a problem that a high quality image cannot be reproduced on recording paper. An object of the present invention is to make it possible to reproduce high-quality images by increasing the rigidity of a casing to which an optical member is attached.

0004

[Means for Solving the Problems] To achieve the above object, the present invention provides a light source that emits a light beam, a polygon mirror that deflects and scans the light beam in a predetermined direction, and a drive means that rotates the polygon mirror. , and an optical member including an imaging lens for forming an image of the light beam deflected by the polygon mirror on the object to be scanned, the first base plate portion;
A casing having a second base plate part having a step with respect to the base plate part and a partition wall part connecting the two base plate parts to each other has a first base plate part partitioned by the first base plate part and the partition wall part. A first storage chamber and a second storage chamber partitioned by the second base plate part and the partition wall part are formed, and the optical member is distributed and arranged in both the storage chambers, and the optical member is arranged in the partition wall part. This is an optical scanning device provided with an aperture through which a beam passes.

[0005]

[Operation] The casing has a first base plate part, a second base plate part having a step with respect to the first base plate part, and a partition part connecting these parts,
It has a bent structure in cross section, making it a highly rigid structure. Therefore, not only when an external force is applied to the casing, but also when heat is generated by the optical member housed in the casing and thermal stress is applied to the casing, the casing will not be deformed by the stress. As a result, the optical path of the light beam formed within the casing does not deviate, and the light beam is irradiated at a predetermined position with high precision, making it possible to reproduce a high-quality image.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The illustrated optical scanning device will be described below. 1 is a sectional view of the optical scanning device, FIG. 2 is a plan view of FIG. 1, and FIG. 3 is a bottom view of FIG. 2. The illustrated casing 10 of the optical scanning device has a first base plate part 11 and a second base plate part 12 having a step with respect to the first base plate part 11.
1 and 12 are interconnected by a partition wall 13. An outer wall portion 14 is integrally formed on the outer periphery of these base plate portions 11 and 12, and this outer wall portion 14 rises upward from here at the base plate portion 11, and extends upward from the base plate portion 11. Since the sections 11 and 12 have a step, the second base plate section 12 descends downward from there. As a result, the first accommodation chamber 16 defined by the first base plate part 11 and the partition wall part 13 and the second accommodation chamber 17 defined by the second base plate part 12 and the partition wall part 13 are separated in the casing 10. is formed.

The upper part of the first storage chamber 16 is covered with a cover (not shown), and FIG. 2 shows the structure inside the first storage chamber 16 in detail with this cover removed. As shown in FIG. 2, a laser diode that emits a laser beam, that is, a light source 21 is attached to the casing 10. The laser beam from this light source 21 is collimated by a collimator lens 22, and then passed through a slit 23. It passes through and reaches the cylindrical lens 24 attached to the first base plate part 11. The laser beam from here is irradiated onto the reflective surface of a polygon mirror 26 rotated by a motor 25 and scanned. Optical members such as the motor 25 are installed inside the first storage chamber 11. The laser beam scanned by this rotating polygon mirror 26 is
An opening 18 is formed in the partition wall portion 13 to allow the light to pass from the storage chamber 16 to the second storage chamber 17 . therefore,
The laser beam scanned by the polygon mirror 26 passes through the aperture 18.
The light passes through the toric lenses 27 attached to the inner surface of the second base plate portion 12, and after passing through the lenses 27, it is reflected by the fθ mirror 28 and reaches the folding mirror 29. These imaging members, such as the fθ mirror 28 and the folding mirror 29, are each attached to the second base plate portion 12 and located within the second storage chamber 17. A cover 19 is attached to the lower surface of the second storage chamber 17, and the internal structure inside the second storage chamber 17 with this cover removed is shown in detail in FIG.

A transparent plate 31 is fixed to a holder 30 attached to the cover 19, and a folding mirror 29
The laser scanning light reflected by the transparent plate 31 passes through the photoreceptor 32 disposed outside the casing 10.
is irradiated. In this way, the optical members such as the rotating polygon mirror 26 and the toric lens 27 arranged in the casing 10 are arranged in the first base plate portion, with the cylindrical lens 24 and the rotating polygon mirror 26 being located in the first housing chamber 16. A toric lens 27, an fθ mirror 28, a folding mirror 29, etc. are located in the second storage chamber 17 and are arranged in the second base plate part 12, and in the two storage chambers 16 and 17, These optical members are distributed and arranged. The laser beam reflected and scanned by the rotating polygon mirror 26 passes through the opening 18 from the first storage chamber 16 to the second storage chamber 17.
However, since the aperture 18 is formed between the rotating polygon mirror 26 and the toric lens 27, the deflection range of the laser beam is smaller than that of the portion transmitted through the transparent plate 31. As shown in FIG. 2 and FIG. 3, the width is about one third. Therefore, since a relatively short opening 18 is formed in the partition wall 13, even if this opening 18 is formed in the partition wall 13, it will not reduce the rigidity of the partition wall 13 itself. It won't happen.

As shown in an enlarged view in FIG. 4, this partition wall portion 13 has a shutter 33 for opening and closing the opening 18.
is slidably attached as shown by the arrow. A slit hole 34 for passing the laser beam is formed in the shutter 33, and the shutter 33 is normally positioned at a position where the slit hole 34 overlaps the opening 18. The circuit is configured so that the light source 21 does not emit light when an operation is performed to open the printer body (for example, in the case of a clamshell type printer, the upper frame is opened) during jam removal or maintenance. In conjunction with this, when the above operation is performed, the shutter 33
slides and the opening 18 is closed by the shutter 33,
The first storage chamber 16 and the second storage chamber 17 are mechanically isolated to ensure worker safety. Moreover, this shutter 33 has a relatively short opening 1.
8, the shutter 33 can be formed from a small member while using the partition wall 13 as a holding member for the shutter 33. This shutter 33
The sliding movement may be performed using a driving means such as a solenoid, or may be linked to the opening/closing operation of a cover or the like.

0010

[Effects of the Invention] As described above, according to the present invention, the first base plate portion, the second base plate portion having a step thereon, and the connection of these base plate portions to the casing that accommodates the optical member. A first storage chamber and a second storage chamber are formed in the casing via the partition wall, and the optical members are distributed and arranged in these two storage chambers, thereby reducing the rigidity of the casing. The casing is not distorted due to heat generated from the optical member, and high-quality images can be reproduced.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing an optical scanning device according to an embodiment of the present invention;

[Fig. 2] is a plan view of Fig. 1;

[Fig. 3] is a bottom view of Fig. 1;

4 is an enlarged cross-sectional view of a part of the partition shown in FIG. 1; FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10... Casing, 11... First base plate part, 12... Second base plate part, 13... Partition wall part, 14... Outer wall part, 16... First storage chamber,
17... Second storage chamber, 18... Opening, 22... Collimator lens, 24... Cylindrical lens, 26... Polygon mirror, 2
7... Toric lens, 32... Photoreceptor.

Claims (1)

[Claims] 1. A light source that emits a light beam, a polygon mirror that deflects the light beam in a predetermined direction and scans it, a driving means that rotates the polygon mirror, and a light beam that is deflected by the polygon mirror that directs the light beam to a scanned object. In an optical scanning device having an optical member including an imaging lens that forms an image, a first base plate part, a second base plate part having a step with respect to the first base plate part, and both base plate parts A first storage chamber partitioned by the first bed plate part and the partition wall part, and a first storage chamber partitioned by the second bed plate part and the partition wall part, in a casing having partition wall parts interconnecting each other. 2
An optical scanning device comprising: a storage chamber, the optical member is distributed and arranged in both the storage chambers, and an opening through which the light beam passes is provided in the partition wall.