JPH10148783A - Optical beam recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the vibration of a polygon motor, and to improve picture quality by providing a damping member arranged between a supporting member and a bearing member and absorbing vibration based on the rotation of the polygon motor. SOLUTION: The damping member 69 is packed in a recessed part 62B on the surface of a stator yoke 62. As the member 69, unvulcanized butyl rubber is the most desirable and a visco-elastic material such as oil clay, silicone rubber or silicon gel can be used in addition. Then the vibration generated by the polygon motor 61 is absorbed by the member 69 packed in the part 62B at the stator yoke 62 magnetically connecting between a coil 65 and the pole of the magnet 68. As the member 69 transduces vibrating energy mainly to thermal energy due to friction between molecules and radiates it, the optical beams of each color irradiated onto a photosensitive body 4 exposes the prescribed position of the body 4 without receiving the influence of the vibration of the polygon motor 61.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light beam recording apparatus, and more particularly to a light beam recording apparatus which suppresses vibration generated by a polygon motor of a light beam scanner to improve image quality.

[0002]

2. Description of the Related Art A light beam recording apparatus emits a light beam modulated in accordance with an image signal, deflects the light beam by a polygon mirror rotated by a polygon motor, and performs sub-scanning by the deflected light beam. The photoreceptor rotated in the main scanning direction is scanned in the main scanning direction to form an electrostatic latent image on the photoreceptor in accordance with an image signal. The electrostatic latent image on the photoreceptor is converted into a toner image by development, the toner image is transferred onto a transfer medium, and after the transfer is fixed and recorded as an image.

In order to improve the quality of an image to be recorded, it is necessary to suppress the fluctuation of the exposure position of the light beam by suppressing the vibration of the polygon motor, and the light beam by suppressing the displacement of the photosensitive member. It is necessary to suppress the fluctuation of the relative position with respect to the position.

[0004] As a conventional light beam recording apparatus which attempts to realize the above, for example, Japanese Patent Application Laid-Open No. Sho 63-3010
No. 74 and JP-A-5-103164.

In the light beam recording apparatus described in Japanese Patent Application Laid-Open No. 63-301074, a light beam scanner provided with a polygon mirror, an Fθ lens, and a reflection mirror is mounted on a frame of a laser printer main body via a vibration isolating material. It has a fixed configuration, and improves image quality by making it difficult for vibrations generated by means other than the light beam scanner to be transmitted to the light beam scanner.

In the light beam recording apparatus described in Japanese Patent Application Laid-Open No. 5-103164, the light beam scanner is fixed to a support member having a natural frequency separated by a predetermined value from the frequency generated by the light beam scanner. It has a configuration as described below. With this configuration, the resonance phenomenon of the support member for fixing the light beam scanner is suppressed, and the image quality is improved.

[0007]

However, according to the conventional light beam recording apparatus, in the apparatus described in Japanese Patent Application Laid-Open No. 63-301074, vibrations generated by means other than the light beam scanner are reflected by the light beam scanner. However, since the vibration of the polygon motor fluctuates the exposure position of the light beam and the relative position with respect to the photoconductor, there is a limit in improving the image quality.

In Japanese Patent Laid-Open No. 5-103064, although the resonance of the support member for fixing the light beam scanner is suppressed, the vibration of the polygon motor causes the light beam to be exposed to light and the photosensitive member to be exposed. There is a limit in improving the image quality because the relative position of the image is changed.

Accordingly, it is an object of the present invention to provide a light beam recording apparatus which suppresses the vibration of a polygon motor and eliminates the limit of improving the image quality.

[0010]

According to the present invention, in order to achieve the above object, a light beam modulated by an image signal is deflected by a polygon mirror driven based on the rotation of a polygon motor. A light beam recording apparatus that forms an electrostatic latent image on the photoconductor by scanning the photoconductor with a beam, and performs image recording based on the electrostatic latent image; and a support member that supports the polygon motor. A rotating shaft of the polygon motor, a bearing member for supporting a rotating system such as a rotor, and a vibration damping member disposed between the supporting member and the bearing member to absorb vibration based on rotation of the polygon motor. A light beam recording device is provided.

In the above-described light beam recording apparatus, the damping member is a viscoelastic member which supports the bearing member and the stator of the polygon motor, and is coated or laminated on a stator yoke member supported by the supporting member. Is preferred. Alternatively, the vibration damping member may support the bearing member and the stator of the polygon motor, and may be a viscoelastic member sandwiched between a pair of stator yoke members supported by the support member. This viscoelastic member preferably has a viscoelastic property of a penetration of 30 or more.

[0012]

FIG. 1 shows a light beam recording apparatus according to a first embodiment of the present invention, wherein 1 is a scanner section for reading an original, 2 is an image forming apparatus main body, and 3 is a paper feeder. A cassette 4, a plurality of photoconductors provided for each color, an optical system 5 for forming an electrostatic latent image on each photoconductor 4, and a plurality of photoconductors 6 for developing the electrostatic latent image with toner of each color A developing unit 7 is a transport belt that is driven to rotate in the direction of arrow A to transport the sheet, and 8 is a fixing device having fixing rolls 8a and 8b. In the optical system 5, a light beam scanner 80 provided for each color is supported by the support frame 70, and includes a semiconductor laser oscillator, a polygon mirror, a reflection mirror, and the like, which will be described later. Reference numeral 9 denotes a paper discharge tray, and reference numeral 10 denotes a manual feed tray.

FIG. 2 shows a light beam scanner 80 arranged on a support frame 70, which emits a light beam (laser beam) whose intensity is modulated by an image signal, and corrects the light beam into collimated light. A collimator lens 52, a cylindrical lens 53 for condensing the light beam in a sub-scanning direction at a predetermined position, and a plane mirror 5 for reflecting the light beam transmitted through the cylindrical lens 53
4, a polygon mirror 55 having a mirror surface for deflecting the light beam rotated by the polygon motor 61, and fθ lenses 56 and 57 for correcting the light beam so that the scanning speed is constant on a predetermined main scanning line. A cylindrical mirror 58 that reflects the light beam onto the predetermined main scanning line and corrects the inclination of the mirror surface of the polygon mirror 55 together with the cylindrical lens 53, and irradiates the predetermined main scanning line with the light beam. It has a photosensitive drum 4 in which an area is located.

FIG. 3 shows a light beam scanner 80 which is a simplified version of the configuration shown in FIG. 2, a support frame 70 for supporting the light beam scanner 80, and the photosensitive member 4. Beam scanner 80
As shown in FIG. 4, a polygonal motor 61 has a flange-shaped stator yoke 62 fixed to a support frame 70.
And the bearing 6 at the cylindrical portion 62A of the stator yoke 62.
A rotating shaft 64 supported via 3A and 63B, a stator 66 formed integrally with the cylindrical portion 62A of the stator yoke 62 and wound with a coil 65, and a rotor yoke pressed into the lower end of the rotating shaft 64 67 and the rotor yoke 67
Is composed of a magnet 68 fixed inside the periphery of
A concave portion 62B on the surface of the stator yoke 62 is filled with a vibration damping member 69. The polygon mirror 55 is positioned at a predetermined position by a rotor hub 55 </ b> A press-fitted above the rotation shaft 64.

The vibration damping member 69 is most preferably made of unvulcanized butyl rubber, but it is also possible to use a viscoelastic material such as oil clay, silicone rubber or silicone gel. Silicon gel is, in particular, the brand name β-
GEL or γ-GEL is good.

Unvulcanized butyl rubber is obtained by adding a terpene resin, a phenolic resin, a chrominine resin, or a petroleum resin as a tackifier to butyl rubber as a raw material, and has a rebound resilience of 2 times as compared with conventional butyl rubber.
It becomes smaller than 0% and the loss coefficient also becomes larger.
Further, since it has a high adhesiveness by itself, it has a characteristic that it adheres well to all the substrates. The same applies to oil-absorbing clay, silicone rubber, and silicone gel.

The viscoelastic material used for the vibration damping member 69 preferably has a penetration of 30 or more according to JIS K220. The penetration is a value obtained by dropping a standard needle with a load of 100 g at 25 ° C. onto a sample and increasing the depth (mm) of the needle that penetrates for 5 seconds by 10 times. Indicates softness. The shear adhesive strength is 0.7
It is preferably at least kg / cm ² .

The operation of the above configuration will be described.

An image signal is generated by the scanner unit 1 based on the reading of the document, and is stored in a memory (not shown) for each color after image processing. When a scanning start signal (SOS) is output from a photodetector (not shown), a light beam modulated according to an image signal read from a memory for each color is emitted from a semiconductor laser 51, and a collimator lens is output. 5
2. Deflected by a polygon mirror 55 rotated by a polygon motor 61 through a cylindrical lens 53 and a plane mirror 54, and passed on the photosensitive member 4 charged by a charger (not shown) through fθ lenses 56 and 57 and a cylindrical mirror 58. Irradiated. On the photoreceptor 4 for each color, a toner image for each color is formed by developing the electrostatic latent image by the developing device 6, and the recording paper fed from the paper feed tray 3 and conveyed on the conveyance belt 7 sequentially. Transferred, fixing unit 8
The recording paper having the fixed image is discharged to the paper discharge tray 9.

The vibration generated by the polygon motor 61 is absorbed by the vibration damping member 69 filled in the concave portion 62B of the stator yoke 62 for magnetically connecting the magnetic poles of the coil 65 and the magnet 68. Since the vibration damping member 69 converts the vibration energy into heat energy based mainly on intermolecular friction and dissipates it, the light beam for each color irradiated on the photoreceptor 4 is not affected by the vibration of the polygon motor 61. A predetermined position of the photoconductor 4 is exposed. Therefore, a high quality image can be obtained.

FIGS. 5A and 5B show the relationship between the vibration of the polygon mirror 55 and time, and FIG.
Shows the amplitude of a conventional light beam scanner without
Is a first example in which the vibration damping member 69 is provided in the concave portion 62B shown in FIG.
3 shows the amplitude in the embodiment. As is clear from the comparison between (a) and (b), in the first embodiment, the vibration is rapidly attenuated. Therefore, in the first embodiment, the vibration damping member 69 absorbs the vibration generated based on the rotation of the polygon motor 61 and suppresses transmission to the support frame 70.

FIG. 6 shows a polygon motor 61 in a light beam recording apparatus according to a second embodiment of the present invention, in which a vibration damping member 69 is arranged in a cross section of a stator yoke 62 fixed to a support frame 70. . Other configurations and functions are the same as those of the first embodiment.

As shown in FIG. 7, the stator yoke 62 is formed by laminating a vibration damping member 69 with metal plates 62a and 62b and integrating them by a roll or a press.

According to such a configuration, since the damping member 69 and the metal plates 62a and 62b are in contact with each other in a wide range, the absorbability of vibration generated due to the rotation of the polygon motor 61 is improved.

[0025]

As described above, according to the light beam recording apparatus of the present invention, since the vibration of the polygon motor is absorbed, the limit of the improvement of the image quality can be eliminated.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a light beam recording device according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram illustrating a light beam scanner according to the first embodiment.

FIG. 3 is an explanatory diagram illustrating a light beam scanner according to the first embodiment.

FIG. 4 is an explanatory diagram showing a polygon motor according to the first embodiment.

5A is a diagram illustrating vibration of a polygon motor 61 that does not use a damping member 69, and FIG. 5B is an explanatory diagram illustrating vibration of the polygon motor 61 that uses a damping member 69. FIG.

FIG. 6 is an explanatory diagram illustrating a polygon motor 61 according to a second embodiment.

FIG. 7 is an explanatory view showing a stator yoke 62 according to a second embodiment.

[Explanation of symbols]

 1, scanner unit 2, image forming apparatus main body 3, paper feed cassette 4, photoconductor 5, optical system 6, developing device 7, transport belt 8, fixing device 8a, 8b, fixing roll 9, paper discharge tray 10, manual feed tray 51, semiconductor laser 52, collimator lens 53, cylindrical lens 54, plane mirror 55, polygon mirror 55A, rotor hub 56, 57, fθ lens 58, cylindrical mirror 61, polygon motor 62, stator yokes 62a, 62b, metal plate 62A, cylinder Part 62B, concave parts 63A, 63B, bearing 64, rotating shaft 65, coil 66, stator 67, rotor yoke 68, magnet 69, vibration damping member 70, support frame 80, light beam scanner

Claims (4)

[Claims] 1. A light beam modulated by an image signal is deflected by a polygon mirror driven based on the rotation of a polygon motor, and the photoreceptor is scanned by the deflected light beam so as to remain on the photoreceptor. In a light beam recording apparatus that forms an electrostatic latent image and performs image recording based on the electrostatic latent image, a support member that supports the polygon motor, and a rotation shaft of the polygon motor, a rotation system such as a rotor are supported. An optical beam recording apparatus, comprising: a bearing member to be driven; and a vibration damping member disposed between the support member and the bearing member to absorb vibrations caused by rotation of the polygon motor. 2. The structure according to claim 1, wherein said vibration damping member is a viscoelastic member which supports said bearing member and a stator of said polygon motor, and is applied or laminated on a stator yoke member supported by said support member. The light beam recording device according to claim 1. 3. The vibration damping member is a viscoelastic member that supports the bearing member and the stator of the polygon motor and is sandwiched between a pair of stator yoke members supported by the support member. Item 2. The light beam recording apparatus according to Item 1. 4. The light beam recording apparatus according to claim 2, wherein said viscoelastic member has a viscoelastic characteristic having a penetration of 30 or more.