JPH1134392A - Deflection scanning apparatus and image forming apparatus loaded therewith - Google Patents

Abstract

PROBLEM TO BE SOLVED: To directly attach the lid member of an optical box to the main body frame of an image forming apparatus. SOLUTION: A lid member 20 is attached to an optical box 10 housing a rotary polyhedral mirror 3, a scanning lens 4 or the like and the extension part 21 of the lid member 20 is fixed to the support part 31 of a main body frame 30 by rivets. By preliminarily regulating the relative position of a positioning unit 24 with respect to the lid member 20, the positioning of the optical box 10 to a rotary drum not shown in a drawing is performed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a deflection scanning device used for an image forming apparatus such as a laser beam printer and a laser facsimile and an image forming apparatus equipped with the same.

[0002]

BACKGROUND ART FIG. 6 shows a deflection scanning apparatus used in an image forming apparatus such as a laser beam printer or a laser facsimile according to one conventional example, the laser beam L ₀ is a light beam generated from the semiconductor laser 101 Collimated by a collimator lens, the cylindrical lens 102
As a result, the light is condensed into a linear light beam and is incident on the reflection surface of the rotary polygon mirror 103. The reflected light is deflected and scanned by the rotation of the rotary polygon mirror 103, and is scanned in the Y-axis direction (main scanning direction).
Of the rotating drum 1 through the scanning lens 104
An image is formed on the photoreceptor 05. The light flux that forms an image on the photoconductor is
An electrostatic latent image is formed by main scanning in the Y-axis direction by rotation of the rotating polygon mirror 103 and sub-scanning in the Z-axis direction by rotation of the rotating drum 105.

In the periphery of the photoreceptor, a charging device for uniformly charging the surface of the photoreceptor, a visualization device for visualizing an electrostatic latent image formed on the surface of the photoreceptor into a toner image, A transfer device or the like for transferring the toner image to a recording medium such as a recording paper is provided.
Is recorded on a recording sheet or the like corresponding to the light beam that generates.

The scanning light of the rotary polygon mirror 103 reaches one end of the scanning surface, and is transmitted through a condenser lens 106a to a BD.
The light is introduced into the sensor 106b, converted into a scanning start signal by a controller (not shown), and transmitted to the semiconductor laser 101. After receiving the scan start signal, the semiconductor laser 101 starts write modulation based on image information transmitted from a host computer (not shown).

A semiconductor laser 101, a cylindrical lens 102, a rotating polygon mirror 103, a scanning lens 104, a BD
The sensor 106b and the like are mounted inside an optical box 110 made of synthetic resin. The rotating drum 105 is provided outside the optical box 110, and one end of the optical box 110 is provided with a window for taking out scanning light from the optical box 110 toward the rotating drum 105.

The scanning lens 104 includes a spherical lens unit and a toric lens unit, and converts scanning light scanned at a constant angular speed by the rotary polygon mirror 103 into scanning light scanning at a constant speed in the Y-axis direction on the rotating drum 105. So-called fθ function.

At the upper end of the side wall of the optical box 110, as shown in FIGS.
Screw hole 110a for fixing the screw 0, and the lid member 1
A positioning pin 110b that engages with the 20 positioning holes is provided. Also, outside the side wall of the optical box 110,
A pair of assembling members 111 protrude, and each assembling member 111 is supported by a screw 112a.
A pair of elongated holes 111 for fastening the optical box 110 to
a and positioning pins 113a of the positioning unit 113
Is provided.

The positioning pins 113a of each positioning unit 113 can be relatively displaced in the X and Y directions within a range allowed by the size of the hole 111b of the assembling member 111. By moving, the relative position of the optical box 110 with respect to the rotating drum 105 is adjusted. This adjustment is to finally adjust the image forming position of the scanning light to form an image on the photoreceptor. After such adjustment is made, the screw 113c penetrating the elongated hole 113b of the positioning unit 113 is optically adjusted. The positioning unit 113 is fixed by tightening into the screw hole 111c of the assembling member 111 of the box 110.

The support plate 112 has both ends mounted on a support portion 131 of a main body frame 130 of the image forming apparatus. The support plate 112 is screwed to the support portion 131 of the main frame 130 by engaging the positioning pin 131a provided on the support portion 131 with the positioning hole of the support plate 112 and tightening the screw 130b.

When the optical box 110 is assembled to the main body frame 130 of the image forming apparatus, the positioning pin 113a is engaged with the positioning hole 112b of the support plate 112 after the positioning by the positioning unit 113 is completed as described above. A step of fixing the optical box 110 to the support plate 112 by 112a is required.

The motor 103a for rotatingly driving the rotary polygon mirror 103 includes a drive circuit (not shown) mounted on a motor board 103b, a stator excited by a drive current of the drive circuit, a rotor opposed thereto, and the like. It is constituted by a magnetic circuit.

[0012]

However, according to the above prior art, when assembling the optical box to the main body frame of the image forming apparatus, as described above, the optical box is provided via the support plate made of a highly rigid sheet metal or the like. Since the optical box is assembled to the main body frame, it takes time to fasten screws and other fasteners.Moreover, many screws are used in addition to the support plate, resulting in a large number of assembly parts. There is an unsolved problem that costs and parts costs increase.

In addition, since the supporting plate, which is a high-rigidity sheet metal member or the like, has a large area and a large weight, there is an inconvenience that the size and weight of the deflection scanning device cannot be promoted.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned unresolved problems of the prior art, and is intended to assemble an optical box directly to a main body frame of an image forming apparatus without using a sheet metal support plate or the like. It is an object of the present invention to provide an inexpensive and high-performance deflection scanning device and an image forming apparatus equipped with the same.

[0015]

In order to achieve the above object, a deflection scanning apparatus according to the present invention comprises a scanning means for deflecting and scanning a light beam generated from a light source, and a photosensitive means for exposing the light beam via the scanning means. An imaging optical system that forms an image on a body, an optical box that houses the imaging optical system and the scanning unit, and a lid member that closes an opening of the optical box, wherein the lid member assembles the optical box. An extension extending to the support of the main body frame and positioning means for positioning the optical box with respect to the support are provided.

[0016]

The lid member is extended to the support portion of the main body frame and directly assembled to the optical box without interposing a support plate made of sheet metal between the optical box and the support portion provided on the main body frame. . Since there is no need to interpose a support plate or the like between the main body frame and the optical box, it is possible to greatly contribute to simplifying the assembling process of the apparatus and reducing the number of assembled parts.

Further, by omitting the high-weight support plate,
The weight of the apparatus can be greatly reduced, and the relative position of the optical box with respect to the rotating drum or the like can be adjusted only once. As a result, it is possible to promote cost reduction and high performance of the image forming apparatus.

[0018]

Embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a deflection scanning device according to an embodiment. A laser beam L _1, which is a light beam emitted from a semiconductor laser 1 as a light source, is collimated by a collimator lens and is linearly converted by a cylindrical lens 2. The light is condensed into a luminous flux, and is incident on the reflection surface of the rotary polygon mirror 3 as the scanning means. The reflected light is deflected and scanned by the rotation of the rotary polygon mirror 3 to become scanning light in the Y-axis direction (main scanning direction), and forms an image on a photosensitive member on a rotating drum (not shown) via the scanning lens 4. The light beam that forms an image on the photoreceptor forms an electrostatic latent image with the main scanning in the Y-axis direction by the rotation of the rotary polygon mirror 3 and the sub-scanning in the Z-axis direction by the rotation of the rotating drum.

In the periphery of the photoreceptor, a charging device for uniformly charging the surface of the photoreceptor, a visualization device for visualizing an electrostatic latent image formed on the surface of the photoreceptor into a toner image, A transfer device or the like for transferring the toner image onto a recording medium such as recording paper is provided, and by these operations, recording information corresponding to the light beam generated by the semiconductor laser 1 is printed on recording paper or the like.

The scanning light of the rotary polygon mirror 3 reaches one end of the scanning surface and passes through the condenser lens 5a to the BD sensor 5b.
And is converted into a scanning start signal by a controller (not shown) and transmitted to the semiconductor laser 1. After receiving the scanning start signal, the semiconductor laser 1 starts writing modulation based on image information transmitted from a host computer (not shown).

The semiconductor laser 1, the cylindrical lens 2, the rotary polygon mirror 3, the scanning lens 4, the BD sensor 5b, etc. are mounted inside an optical box 10 made of synthetic resin. The rotating drum is provided outside the optical box 10 and the optical box 1
A window for taking out the scanning light from the optical box 10 toward the rotating drum is provided at one end of 0.

The scanning lens 4 includes a spherical lens unit and a toric lens unit, and converts scanning light scanned at a constant angular speed by the rotary polygon mirror 3 into scanning light scanning at a constant speed in the Y-axis direction on the rotating drum. It has a so-called fθ function.

After assembling the cylindrical lens 2, the rotary polygon mirror 3, the scanning lens 4 and the like on the bottom wall and the like of the optical box 6, as shown in FIG. It is closed by the lid member 20. The lid member 20 is a plate-shaped body made of a highly rigid metal, and has extension portions 21 protruding to the side of the optical box 10.
A positioning unit 24 as positioning means for adjusting the relative position of the optical box 10 with respect to the rotating drum is provided.

When assembling the optical box 10 to the main body frame 30 of the image forming apparatus, the extension portions 21 of the lid members 20 projecting outside the side wall of the optical box 10 are respectively attached.
The extension portions 21 are mounted on a pair of support portions 31 of the main body frame 30 and each extension portion 21 is screwed with a screw 23 as shown in FIG.

More specifically, at the upper end of the side wall of the optical box 10, a screw hole 10a for screwing the lid member 20 with the screw 22 and a positioning hole 20 for the lid member 20 are provided.
a positioning pin 10b engaging with the optical box 10 is provided. When the lid member 20 is assembled to the optical box 10, the positioning hole 20a is engaged with the positioning pin 10b of the optical box 10, and the lid member 20 is screwed with the screw 22. It is done by stopping.

In this manner, the lid member 20 is placed on the optical box 10.
Then, the positioning pin 24a of the positioning unit 24 is loosely fitted into the hole 20b of each extension 21 of the lid member 20. Using a special jig at the factory site, cover member 2
The relative position between the extension 21 of the zero and the positioning unit 24 is adjusted in the X and Y directions, and the relative position with respect to the rotating drum when the optical box 10 is assembled to the main body frame 30 is adjusted in advance. Subsequently, the positioning unit 24 is screwed to the extension 21 of the lid member 20 with a screw 24b.

Finally, the optical box 10 with the lid member 20 assembled is carried into the main body frame 30 of the image forming apparatus, and each extension 21 of the lid member 20 is placed on the support part 31 of the main body frame 30. The positioning pin 24a of the positioning unit 24 is engaged with the positioning hole of the
Tighten 3. Thus, the lid member 20 is fixed to the support portion 31 of the main body frame 30.

According to this embodiment, since the optical box is directly assembled to the main body frame by using the extension of the lid member, a support plate is not required between the two as in the conventional example. The number of screwing steps required for assembling the device can be reduced, and the assembling process can be greatly simplified.

By omitting the support plate and the screws, the number of assembly parts of the apparatus can be greatly reduced, and the alignment of the optical box with respect to the rotating drum is easy.

Further, since it is only necessary to extend the both sides of the lid member to slightly increase the dimensions of the lid member, even if the lid member is made of metal, it is necessary to use a metal plate and a heavy supporting plate. On the contrary, there is an advantage that the weight reduction of the device can be greatly promoted.

FIG. 3 shows a modification. This is optical box 1
The positioning unit of FIGS. 1 and 2 is omitted by adjusting the relative position of the optical box 10 with respect to the rotating drum by using a fastening portion for screwing the lid member 40 to zero. is there. A large hole 40a having a large dimension is provided in the lid member 40, and a screw 42 is temporarily fixed to the hole. I do. Thereby, the relative position with respect to the rotating drum when the optical box 10 is assembled to the main body frame 50 is adjusted. Subsequently, the screw 42 is tightened to fix the lid member 40 to the optical box 10.

In this manner, the lid member 40 is attached to the optical box 10.
Is loaded into the main body frame 50 of the image forming apparatus, and the positioning holes 4 of the extension portions 41 of the lid member 40 are provided.
0b, the positioning pin 5 of the support portion 51 of the main body frame 50
1a is engaged, and the lid member 40 is screwed to the support portion 51 with a screw 51b.

Although this modification has an advantage that the number of assembly steps and the number of assembly parts can be reduced by omitting the positioning unit, the optical member 10 is removed from the lid member 40 after the lid member 40 is assembled to the main body frame 50. When they are removed, there is no positioning unit for positioning them, so a positioning step using a special jig is required again.

In the present embodiment, the optical member is fixed to the main body frame so that the optical box is assembled to the image forming apparatus in a state of being suspended from the lid member. As shown, the assembly of the lid member 60 to the optical box 10 is turned upside down, and the lid member 60 is turned upside down.
May be fixed to the support portion 71 of the main body frame 70.

As described above, since the optical box can be freely attached to the main body frame from either the upper or lower direction, there is a remarkable advantage that the degree of freedom in designing the image forming apparatus is greatly increased. .

[0037]

Since the present invention is configured as described above, it has the following effects.

The optical box can be assembled by directly screwing a lid member closing the opening of the optical box to the main body frame of the image forming apparatus. As a result, the cost of parts and the cost of assembling the image forming apparatus can be significantly reduced, and the weight of the apparatus can be greatly reduced.

[Brief description of the drawings]

1A and 1B show a deflection scanning device according to an embodiment, in which FIG. 1A is a schematic plan view showing a state where a lid member is removed, and FIG. 1B is a partially sectional elevation view showing a state where the lid member is attached. FIG.

FIG. 2 is a plan view showing the device of FIG. 1 (b).

FIG. 3 is a plan view showing a modification.

FIG. 4 is a partial sectional elevation view showing the device of FIG. 3;

FIG. 5 is a partial elevational view showing another modification.

FIG. 6 is a schematic plan view showing a deflection scanning device according to a conventional example.

FIG. 7 is an exploded perspective view showing a part of the apparatus of FIG. 6 in an exploded manner.

FIG. 8 is a plan view showing a state in which a lid member is attached to the apparatus of FIG. 6 and assembled to a main body frame.

9 is an elevational view, partially in section, showing the apparatus of FIG. 8;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Semiconductor laser 2 Cylindrical lens 3 Rotating polygon mirror 4 Scanning lens 10 Optical box 20,40,60 Lid member 21,41,61 Extension part 24 Positioning unit 30,50,70 Body frame 31,51,71 Support part

Claims (5)

[Claims] 1. A scanning unit for deflecting and scanning a light beam generated from a light source, an imaging optical system for forming an image of the light beam on a photosensitive member via the scanning unit, the imaging optical system, and the scanning unit An optical box that houses the optical box, a lid member that closes the opening of the optical box, the lid member extends to a support portion of the main body frame to which the optical box is assembled, and the optical box with respect to the support portion. A deflection scanning device comprising a positioning means for performing positioning. 2. The deflection scanning device according to claim 1, wherein the lid member is a plate-like body made of a highly rigid metal. 3. The deflection scanning device according to claim 1, wherein the positioning means is configured to position the extension of the lid member with respect to the support. 4. The deflection scanning device according to claim 1, wherein the positioning means is configured to position the lid member with respect to the optical box. 5. An image forming apparatus comprising: the deflection scanning device according to claim 1; and a main body frame to which the optical box is assembled.