JP2002341467A - Sheet metal base mechanism for optical unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide sheet metal base structure for an optical unit restraining vibration generated by a motor or the like from being transmitted to the optical unit fixed on the main body frame of an image forming device and contriving the lightening of a sheet metal base being a reinforcing member. SOLUTION: The part of the sheet metal base unnecessary in terms of securing rigidity is constituted of resin or a thin sheet metal. Or the part unnecessary in terms of securing the rigidity is lightened and a flange part (2d) is provided around the lightened part (2c) so as to enhance rigidity, and then the lightened part (2c) is fixed by resin or a lightweight member such as the sheet metal being another member. Fixing by spot welding, burring caulking or a screw is considered as the fixing means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a sheet metal base structure for fixing an optical unit used in an electrophotographic image forming apparatus.

[0002]

2. Description of the Related Art An optical unit used in an electrophotographic image forming apparatus exposes and scans a photosensitive member with a laser beam to form an electrostatic latent image on the surface of the photosensitive member. Exposure with laser light is suitable for obtaining high image quality because of high accuracy, but on the other hand, it is susceptible to minute vibrations caused by a motor or the like, and image density unevenness may occur.

[0003] In order to prevent image deterioration due to vibration, the following various techniques have been proposed. Japanese Patent Application Laid-Open No. 1-195411 discloses a technology in which an elastic vibration isolating member is provided between a main body frame of an image forming apparatus and an optical unit, and vibration transmitted from a driving unit or a photoreceptor unit is absorbed by the vibration isolating member. is suggesting. However, although the transmission of vibration can be suppressed by the above technique, there is a problem that it is difficult to position the optical unit with high accuracy.

Japanese Patent Application Laid-Open No. 11-95149 proposes a technique in which an optical unit is fixed to a main body frame via a rigid reinforcing member to attenuate vibration with the reinforcing member. Accordingly, transmission of vibration can be suppressed, and highly accurate positioning of the optical unit can be performed. However, it is necessary to increase the rigidity of the reinforcing member in order to reliably suppress the transmission of vibration, but there is a problem that the weight of the reinforcing member increases because the plate pressure is increased to increase the rigidity.

Japanese Patent Application Laid-Open No. 2000-292730 proposes a technique in which vibration is prevented from being transmitted by taking into consideration the screwing position of the optical unit with respect to the main body frame.

In Japanese Patent Application Laid-Open No. 2000-238326, an optical unit cover is provided with a vibration damping property and the size of a closed space in the optical unit is adjustable, so that one of the vibration generating sources is provided. We have proposed a technology that can adjust a certain acoustic resonance frequency.

[0007]

SUMMARY OF THE INVENTION In view of the above problems, the present invention suppresses the transmission of vibration from a motor or the like to an optical unit fixed to a main body frame of an image forming apparatus.
An object of the present invention is to provide a sheet metal base structure of an optical unit which enables high-quality image formation and reduces the weight of a sheet metal base as a reinforcing member.

[0008]

According to a first aspect of the present invention, there is provided a sheet metal base structure for fixing an optical unit of an image forming apparatus. A sheet metal base structure of the optical unit characterized in that a portion not requiring rigidity is made of a lightweight member.
According to a second aspect of the present invention, in the sheet metal base structure of the optical unit according to the first aspect, a bonded steel plate obtained by bonding steel plates having different thicknesses is press-formed and used for a portion requiring rigidity. The optical unit has a sheet metal base structure.

According to a third aspect of the present invention, in the sheet metal base structure of the optical unit according to the first aspect, a portion not requiring rigidity is lightened, and the periphery of the lightened lightened portion is formed as a flange. The optical unit has a sheet metal base structure characterized by increasing rigidity and fixing the hollow portion with a lightweight member. The present invention described in claim 4 is the invention according to claim 1 or 3.
3. The sheet metal base structure of the optical unit according to the item 1, wherein the lightweight member is made of a resin. According to a fifth aspect of the present invention, in the sheet metal base structure of the optical unit according to the third or fourth aspect, the lightening portion is fixed by a sheet metal of another member. .

According to a sixth aspect of the present invention, in the sheet metal base structure of the optical unit according to the fifth aspect, the sheet metal of another member of the lightening portion is fixed by spot welding. Base structure. According to a seventh aspect of the present invention, in the sheet metal base structure of the optical unit according to the fifth aspect, the sheet metal of another member of the lightening portion is fixed by burring caulking. I do. According to an eighth aspect of the present invention, in the sheet metal base structure of the optical unit according to the fifth aspect, a sheet metal of another member of the lightening portion is fixed with screws. .

[0011]

Embodiments of the present invention will be described below with reference to the drawings. First, the outline of the process of the image forming apparatus will be described. 2. Description of the Related Art An electrophotographic image forming apparatus irradiates a document with a light source and uses the reflected light to expose and scan the surface of a photoconductor with an optical unit. An electrostatic latent image is formed on the exposed surface of the photoconductor, and the electrostatic latent image becomes a toner image visualized by a developing device. The toner image is transferred onto a transfer sheet conveyed from a sheet feeding device, fixed through a fixing device, and discharged. The optical unit includes a laser, a lens, a mirror, and the like, and includes a semiconductor laser optical system, an LED optical system, and the like.

FIGS. 1A and 1B show a mounting structure of an optical unit in an image forming apparatus, wherein FIG.
(B) is a sectional view. A sheet metal base (2), which is a rigid reinforcing member to which the optical unit (1) is fixed, is supported by a body frame side plate (3), and the body frame side plate (3) further includes a drive unit (4) and a photoconductor unit (5). ).

FIG. 2 is a perspective view showing a sheet metal base of the optical unit of the present invention. The sheet metal base (2) to which the optical unit (1) is fixed includes a thick plate portion (2a) and a thin plate portion (2b), and a boundary portion is joined by laser welding, and is pressed after joining. Thick plate part (2a) has a thickness of 1.2 to 2.0 mm
And the thickness of the thin plate portion (2b) is preferably about 0.6 mm. At this time, the thin plate portion (2b) is connected to the CAE (Computer).
-Aided Engineering) shows that it is a part that does not contribute to the rigidity from the result of analysis, and the rigidity does not decrease even if it is made thin. Therefore, the sheet metal base (2)
Stiffness can be ensured, transmission of vibration can be suppressed, and weight reduction can be achieved.

FIG. 3 is a perspective view showing a sheet metal base of the optical unit of the present invention. The sheet metal base (2) has a lightening portion (2c) and is fixed by a separate lightweight member. A flange portion (2d) is formed around the lightening portion (2c). At this time, the lightening portion (2c) is a portion that does not contribute to the rigidity based on the result of the analysis by CAE, and the rigidity does not decrease even when the lightening is performed. Further, the light-weight member of the lightening portion (2c) is made of resin, so that the weight can be reduced and the cost can be reduced. The rigidity of the sheet metal base (2) is increased by providing the flange portion (2d). Accordingly, the rigidity of the sheet metal base (2) is ensured to suppress the transmission of vibration, and
Lightening can be achieved.

Alternatively, a sheet metal which is lighter than the member forming the sheet metal base (2) is used as another member to be fixed to the lightening portion (2c). The sheet metal is fixed to the sheet metal base (2) by spot welding. Therefore, it is possible to secure the rigidity of the sheet metal base (2), suppress transmission of vibration, and achieve weight reduction.

Alternatively, another sheet metal to be fixed to the lightening portion (2c) is fixed by burring caulking.

Alternatively, a separate sheet metal to be fixed to the lightening portion (2c) is fixed with screws.

[0018]

As described above, according to the present invention,
An object of the present invention is to provide a sheet metal base structure of an optical unit that can secure the rigidity of the sheet metal base and reduce the weight by forming unnecessary portions in terms of securing rigidity in the sheet metal base structure of the optical unit. Can be.

[Brief description of the drawings]

FIG. 1 is a top view and a cross-sectional view illustrating a mounting structure of an optical unit in an image forming apparatus.

FIG. 2 is a perspective view showing a sheet metal base of the optical unit of the present invention.

FIG. 3 is a perspective view showing a sheet metal base of the optical unit of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Optical unit 2 Sheet metal base 2a Thick plate part 2b Thin plate part 2c Lightening part 2d Flange part 3 Body frame side plate 4 Drive unit 5 Photoconductor unit

Claims (8)

[Claims] 1. A sheet metal base structure for fixing an optical unit of an image forming apparatus, wherein a part of the sheet metal base which does not require rigidity is made of a lightweight member. 2. The sheet metal base structure of the optical unit according to claim 1, wherein a bonded steel sheet obtained by bonding steel sheets having different thicknesses is press-formed.
A sheet metal base structure of an optical unit, which is used for a part requiring rigidity. 3. The thinned portion of the optical unit according to claim 1, wherein a portion having no rigidity is lightened, and the periphery of the lightened portion is flanged to increase the rigidity. A sheet metal base structure of the optical unit, wherein the base member is fixed by a lightweight member. 4. The sheet metal base structure of an optical unit according to claim 1, wherein the lightweight member is made of resin. 5. The sheet metal base structure of an optical unit according to claim 3, wherein the lightening portion is fixed by a sheet metal of another member. 6. The sheet metal base structure of an optical unit according to claim 5, wherein the sheet metal of another member of the lightening portion is fixed by spot welding. 7. The sheet metal base structure of an optical unit according to claim 5, wherein the sheet metal of another member of the lightening portion is fixed by burring caulking. 8. The sheet metal base structure of an optical unit according to claim 5, wherein a sheet metal of another member of the lightening portion is fixed with screws.