JP2001117042A - Optical deflecting scanner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To keep a rolling bearing rotatably supporting a rotary polygon mirror in a excellent lubricant state over a long term. SOLUTION: In the rolling bearing 2 rotatably supporting the rotary polygon mirror 1, the contact part of an outer ring 22 and an inner ring 24 with a ball 23a are made lubricant by the oil of grease 26 with which the inside of the outer ring 22 is charged and oil oozed from an oil impregnation member 29 functioning also as the spring seat of a pressuring spring 28. In this case, its service life is longer and trouble occurrence such as rotary jitter or the like is less than the case of lubrication performed only by the grease 26.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art A light deflection scanning device used in an image forming apparatus such as a laser beam printer or a laser facsimile is
A light beam such as a laser beam is deflected and scanned by a rotating polygon mirror that rotates at a high speed, and the obtained scanning light is focused on a photosensitive member on a rotating drum to form an electrostatic latent image. Next, the electrostatic latent image on the photoreceptor is visualized into a toner image by a developing device, transferred to a recording medium such as recording paper, sent to a fixing device, and printed by heating and fixing the toner on the recording medium ( Print) is performed.

FIG. 4 shows a main part of an optical deflection scanning apparatus according to a conventional example.
, A rotating magnet 103 integrally supported by the rotating shaft 103, and a bearing 1
02 and the motor board 105 integrated with the housing 120
, And the rotor magnet 104 is disposed so as to face the stator coil 106, and both constitute a motor that drives the rotary polygon mirror 101 to rotate. The rotary polygon mirror 101 is pressed against the boss of the rotor magnet 104 by a pressing spring 107, and is integrated with this.

When the stator coil 106 is excited by a drive current supplied from a drive circuit 105a on a motor board 105, the rotor magnet 104 is rotated by the polygon mirror 1.
01, rotates at a high speed together with 01, and deflects and scans the light beam applied to the rotating polygon mirror 101 as described above.

The upper opening of the optical box 110 is
After the optical components such as the rotary polygon mirror 101 are incorporated therein, the lid 111 is closed.

[0006] As shown in FIG. 4 (b), the bearing 102 has a sleeve 12 held inside a housing 120.
1 and a rolling bearing having a pair of upper and lower ball rows 123 held on the inner side thereof via an outer ring 122. The sleeve 121 and the outer ring 122, and the sleeve 121 and the housing 120 are fixed to each other by a method such as adhesion. Have been.

Each ball row 123 is disposed between an inner ring 124 and an outer ring 122 formed by a groove of the rotating shaft 103, and the balls 123 a of each ball row 123 are held at equal intervals in a circumferential direction by a retainer 125. ing. When the above-described motor is driven and the rotating shaft 103 rotates, each ball 123a revolves around the rotating shaft 103 while rotating between the outer ring 122 and the inner ring 124, and rotatably supports the rotating shaft 103. Note that grease 126 is attached to the inside of the outer ring 122.

The fitting of each ball 123a of the ball array 123 with the outer ring 122 and the inner ring 124 is highly accurate, and the contact pressure of each ball 123a is extremely high. If such foreign matter is caught, troubles such as generation of loud noise, deterioration of accuracy due to damage of parts, and shortening of the life of the bearing occur. Therefore, a seal member 127 made of metal or plastic is attached to the outer ring 122 to close the bearing gap and to prevent dust and the like from entering the inside of the bearing.

As described above, the inner ring 124 is
However, similarly to the outer ring 122, the annular member serving as the inner ring 124 may be manufactured separately and fixed to the rotating shaft 103.

The ball 123a of each ball row 123 is provided with a pressurizing spring 12 for urging the upper and lower outer rings 122 in opposite directions.
8 presses against the inner race 124. That is, the pressurizing spring 128 is incorporated between the upper and lower outer rings 122 in a compressed state.
As shown by the arrow A, the ball row 123 is restrained between the rolling groove 124a of the inner ring 124 and the rolling groove 122a of the outer ring 122, and as a result, the ball 123a revolves on a certain orbit. The retainer 125 is provided so that the ball 123a revolves while keeping a constant interval in the circumferential direction.

When the rotating shaft 103 rotates, each ball 123a revolves around the rotating shaft 103 while rotating between the inner ring 124 and the outer ring 122. As mentioned above, ball 1
In the contact portion between the inner ring 124a and the outer ring 122,
As shown by the arrow A in FIG. 4B, a compression force (pressurization) is acting on the ball 123a, and there is no backlash or the like. That is, the ball 123a is freely rotated and moved in the circumferential direction around the axis by the pressurization of the pressurizing spring 128, but is restrained in other directions. Therefore, the rotation of the rotating shaft 103 is free, and furthermore, shaft runout and axial vibration can be suppressed to an extremely small level. As a result, a high-precision bearing function required as an optical deflection scanning device can be realized.

Ball 123a, inner ring 124, outer ring 122
The contact area is very small and is in contact with high pressure. For this reason, when the contact portion is dry, a very loud noise is generated, and the component is damaged, thereby deteriorating accuracy and life.
Therefore, as shown in FIG. 5, grease 126 is generally sealed for lubrication, and oil 126a contained therein always wets the surface of each component of the bearing. It is very important that this film of oil 126a, or oil film, be maintained throughout the operation of the bearing.

Grease 126 is a viscous, semi-solid mixture of a thickener and an oil.
Grease 126 is adhered to the inner surface of outer ring 122. Then, the oil 126a oozing out of the grease 126
Spreads while wetting the surface of the outer ring 122. Eventually, the oil 126a reaches a contact portion between the outer ring 122 and the ball 123a and exerts a lubricating action.

When the ball 123a rotates, an oil film of the oil 126a adheres to the surface thereof, and the oil film eventually becomes the outer ring 12a.
2. It spreads to the ball 123a, the inner ring 124, and the retainer 125, and spreads over the entire rotating part of the bearing.

The oil film gradually oxidizes and deteriorates due to long-term use of the bearing 102 and is lost from the surface of the component. However, as long as the grease 126 retains the oil, the oil film is gradually supplied. As a result, the lubrication state can be kept good.

[0016]

However, according to the above-mentioned prior art, when the grease is excessively filled to maintain the oil film for a long period of time, a part of the grease is caught between the outer ring and the ball. Since the rolling resistance of the ball increases and the loss torque in the rotation of the rotating shaft also fluctuates irregularly, a change in the rotation speed of the motor, that is, a so-called rotation jitter occurs, and as a result, image unevenness of a laser beam printer or the like occurs.

Since grease is originally a semi-solid material, its shape and application position are easily moved by temperature changes and vibrations, and there is a limit in increasing the application amount in order to prevent the above-mentioned entrapment from occurring. Was.

In recent years, a motor for driving a rotary polygon mirror, that is, a scanner motor has been increasingly required to have a higher speed and a quieter apparatus, and it has been desired to maintain a better lubricating state than ever. However, as described above, there is an unsolved problem that the amount of grease applied cannot be easily increased, and the life at high speed rotation is limited.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned unsolved problems of the prior art, and maintains a very good lubricating state of a rolling bearing for rotatably supporting a rotary polygon mirror for a long period of time. It is another object of the present invention to provide a light deflection scanning device having high optical performance.

[0020]

In order to achieve the above object, an optical deflection scanning apparatus according to the present invention comprises: a rotary polygon mirror for deflecting and scanning a light beam; a rolling bearing for rotatably supporting the rotary polygon mirror; It has a motor for rotating and driving the polygon mirror, and an oil-impregnated member is in contact with at least one of the inner ring and the outer ring of the rolling bearing.

A rotary polygon mirror for deflecting and scanning the light beam, a rolling bearing for rotatably supporting the rotary polygon mirror, and a motor for rotating and driving the rotary polygon mirror, wherein the oil-impregnated member abuts the ball of the rolling bearing It may be.

[0022]

When the amount of grease supplied between the inner ring and the outer ring is increased in order to extend the life of the rolling bearing, the grease is caught between the balls and causes troubles such as rotational jitter. Therefore,
The inner ring, the outer ring and the oil-impregnated member abut on at least one of the balls, and oil that oozes from the oil-impregnated member,
Make up for the shortage of grease.

That is, the lubricating state of the bearing can be maintained extremely well over a long period of time by the oil content of both the grease supplied to the rolling bearing and the oil-containing member incorporated inside the rolling bearing.

As a result, a light deflection scanning device having high optical performance, quietness and long life can be realized.

[0025]

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

FIG. 1 shows an optical deflection scanning device according to an embodiment, which comprises a rotating shaft 3 supported on a optics box 10 via a rolling bearing 2 and a rotor coupled to the rotating shaft 3. A magnet 4 and a stator coil 6 fixed to a motor substrate 5 integral with the housing 20 of the rolling bearing 2
And the rotor magnet 4 is disposed so as to face the stator coil 6, and forms a motor that rotationally drives the rotary polygon mirror 1. The rotary polygon mirror 1 is pressed against the rotor magnet 4 by a holding spring 7 and is integrated with the rotor magnet 4.

When the stator coil 6 is excited by the drive current supplied from the drive circuit 5a on the motor substrate 5, the rotor magnet 4 rotates at a high speed together with the rotary polygon mirror 1 and irradiates the rotary polygon mirror 1. The light beam is deflected and scanned.

The upper opening of the optical box 10 is closed by a lid member 11 after incorporating optical components such as the rotary polygon mirror 1 into the optical box 10.

The rolling bearing 2 has a sleeve 21 held inside a housing 20 and a pair of upper and lower ball rows 23 held via an outer ring 22, respectively, inside the sleeve 21. The sleeve 21 and the outer ring 22, The sleeve 21 and the housing 20 are fixed to each other by a method such as bonding.

Each ball row 23 is disposed between the inner ring 24 and the outer ring 22 formed by the groove of the rotating shaft 3, and a plurality of balls 23 a of each ball row 23 are equally spaced in the circumferential direction by a retainer 25. Is held. When the motor is driven to rotate the rotating shaft 3 as described above, each ball 23a revolves around the rotating shaft 3 while rotating between the outer ring 22 and the inner ring 24, and rotatably supports the rotating shaft 3. Grease 26 is applied to the inside of the outer ring 22.

Each ball 23a of the ball row 23 and the outer ring 22
And the inner ring 24 is fitted with high precision, and each ball 23a
Is extremely high. Therefore, if a foreign substance such as dust is caught between each ball 23a and the outer ring 22 or the inner ring 24, a loud noise is generated, the accuracy is deteriorated due to damage of parts, etc. Troubles such as shortening of bearing life are caused. In view of this, a method has been devised in which a seal member 27 is attached to the inner surface of the outer ring 22 to prevent dust and the like from entering the inside of the bearing.

The seal members 27 are disposed at the upper and lower ends of the rolling bearing 2, respectively, and close the bearing gap between each outer ring 22 and the rotating shaft 3.

As described above, the inner race 24 is constituted by a rolling groove formed directly on the outer peripheral surface of the rotary shaft 3, but, like the outer race 22, an annular member serving as the inner race 24 is manufactured separately. It may be fixed to the rotating shaft 3.

The balls 23a in each ball row 23 are pressed against the inner ring 24 by a pressurizing spring 28 which urges the upper and lower outer rings 22 in opposite directions. That is, the pressurized spring 28 is incorporated between the upper and lower outer rings 22 in a compressed state, and the pressurized spring 28 causes the ball row 23 to move the ball row 23 between the rolling groove of the inner ring 24 and the outer The ball 23a revolves on a certain trajectory. The retainer 25 is provided so that the ball 23a revolves while keeping a constant interval in the circumferential direction.

An oil-impregnated member 29 constituting a spring seat of a pressurized spring 28 is in contact with the outer ring 22.
9 and the oil of the grease 26 so as to maintain a good lubrication state between the ball 23a, the outer ring 22, and the inner ring 24.

More specifically, as shown in FIG. 2, first, the grease 26 removes oil 26 from inside with time.
a, and the oil 26a travels along the surface of the rolling groove of the outer race 22, reaches the contact portion with the ball 23a, and performs a lubricating action.

On the other hand, the oil-impregnated member 29 is brought into close contact with the outer ring 22 by a pressurizing spring 28, and oozes out the oil 29a from the inside with time, and the oil 29a travels along the surface of the rolling groove of the outer ring 22, The lubrication action is performed by reaching the contact portion with 23a.

The oil-impregnated member 29 is made of a material such as a so-called oil-impregnated metal obtained by impregnating a porous sintered metal with oil under high pressure, or a so-called oil-impregnated plastic obtained by dispersing oil in a synthetic resin and solidifying it. As described above, the pressure spring 28 also serves as a spring seat.

Since the oil-containing member is larger in volume than grease, it stores a sufficient amount of oil, and the supply of oil gradually continues from there. As a result, it is possible to obtain a long-term oil film holding ability, which was difficult with conventional grease alone. In addition, since the oil-containing member is solid and is supplied with only oil, there is no risk of rolling resistance of the ball and no possibility of occurrence of rotation jitter. As a result, the bearing can maintain quiet and long-life rotation.

The motor and the bearing are not limited to the above shapes. For example, the motor is not limited to the radial gap type outer rotor type, but may be an axial gap type or inner rotor type.

The bearing may be either an inner ring rotating type or an outer ring rotating type rolling bearing. Further, the oil-impregnated member is not only in contact with the outer ring, but for example, a sleeve-shaped member may be in contact with the inner ring by means such as press fitting, or the oil-impregnated member is provided on both the outer ring and the inner ring, and The oil holding capacity may be improved.

Further, the pressurizing means when the upper and lower ball rows are used by pressurizing them is not limited to the above-mentioned pressurizing spring, but may be other urging means.

Further, a retainer for holding the ball, a pressurized spring or a sleeve directly in contact with the outer ring may be an oil-containing member.

FIG. 3 shows the entire light deflection scanning device.
It has a light source 51 that generates a light beam (light flux) such as laser light, and a cylindrical lens 51a that condenses the laser light linearly on the reflection surface 1a of the rotary polygon mirror 1.
The light beam is deflected and scanned by the rotation of the rotary polygon mirror 1 and passes through an imaging lens system 52 to a photosensitive drum 53 on a rotating drum.
Image. The imaging lens system 52 includes a spherical lens 52a,
It has a toric lens 52b and the like, and has a so-called fθ function for correcting the scanning speed and the like of a point image formed on the photoconductor 53.

When the rotary polygon mirror 1 is rotated by the motor, its reflection surface 1a rotates at a constant speed around the axis of the rotary polygon mirror 1. Generated from the light source 51 as described above,
The angle between the optical path of the light beam condensed by the cylindrical lens 51a and the normal to the reflecting surface 1a of the rotating polygon mirror 1, that is, the angle of incidence of the light beam on the reflecting surface 1a, changes with time as the rotating polygon mirror 1 rotates. And the reflection angle also changes, so that the point image formed by condensing the light beam on the photoconductor 53 moves (scans) in the axial direction (main scanning direction) of the rotating drum.

The imaging lens system 52 focuses the light beam reflected by the rotary polygon mirror 1 on the photosensitive member 53 into a point image having a predetermined spot shape, and scans the point image in the main scanning direction. Is designed to keep the speed constant.

The point image formed on the photoreceptor 53 is electrostatically generated by the main scanning by the rotation of the rotary polygon mirror 1 and the sub-scanning by the rotation of the rotating drum having the photoreceptor 53 around its axis. Form a latent image.

Around the photosensitive member 53, a charging device for uniformly charging the surface of the photosensitive member 53, and a charging device for visualizing an electrostatic latent image formed on the surface of the photosensitive member 53 into a toner image. A developing device, a transfer device for transferring the toner image to recording paper, and the like are arranged, and recording information by a light beam generated from the light source 51 is printed on recording paper or the like.

The detection mirror 54 reflects the light beam on the upstream side in the main scanning direction from the optical path of the light beam incident on the recording information writing start position on the surface of the photoreceptor 53, and receives a light receiving element 55 having a photodiode or the like. To the light receiving surface of The light receiving element 55 outputs a scanning start signal for detecting a scanning start position (write start position) when the light receiving surface is irradiated with the light beam.

The light source 51 generates a light beam corresponding to a signal given from a processing circuit for processing information from the host computer. The signal given to the light source 51 corresponds to information to be written on the photoconductor 53, and the processing circuit represents information corresponding to one scanning line which is a locus formed by a point image formed on the surface of the photoconductor 53. The signal is given to the light source 51 as one unit. This information signal is transmitted to the light receiving element 55
Are transmitted in synchronization with the scanning start signal given by

The rotary polygon mirror 1, the imaging lens system 52 and the like are housed in the optical box 10, and the light source 51 and the like are mounted on the side wall of the optical box 10. After the rotating polygon mirror 1, the imaging lens system 52, and the like are assembled in the optical box 10, the lid member 11 is attached to the upper opening of the optical box 10.

[0052]

Since the present invention is configured as described above, the following effects can be obtained.

The rolling bearing that rotatably supports the rotating polygon mirror that rotates at high speed is effectively prevented from being in a state of poor lubrication, the quietness of the bearing portion is maintained, the bearing performance is improved, and the life is extended. And a high image quality can be realized by suppressing the rotation jitter of the rotating polygon mirror. By mounting such a light deflection scanning device, it is possible to promote higher performance and longer life of the image forming apparatus.

[Brief description of the drawings]

FIG. 1 shows a main part of an optical deflection scanning apparatus according to an embodiment, (a) is a schematic sectional view thereof, and (b) is (a).
FIG. 4 is an enlarged partial cross-sectional view showing only a rolling bearing of FIG.

FIG. 2 is a partially enlarged sectional view showing a part of the rolling bearing of FIG. 1 in a further enlarged manner.

FIG. 3 is a diagram illustrating the entire light deflection scanning device.

4A and 4B show a conventional example, in which FIG. 4A is a schematic cross-sectional view, and FIG. 4B is an enlarged partial cross-sectional view showing only the rolling bearing of FIG.

FIG. 5 is a partially enlarged cross-sectional view showing a portion indicated by an ellipse B in FIG. 4 in a further enlarged manner.

[Explanation of symbols]

 Reference Signs List 1 rotating polygon mirror 2 rolling bearing 3 rotating shaft 4 rotor magnet 6 stator coil 21 sleeve 22 outer ring 23 ball row 23a ball 24 inner ring 25 retainer 27 seal member 28 pressurizing spring 29 oil impregnated member

Claims (7)

[Claims] A rotary polygon mirror for deflecting and scanning a light beam;
A light bearing, comprising: a rolling bearing that rotatably supports the rotating polygon mirror; and a motor that rotationally drives the rotating polygon mirror. An oil-impregnated member is in contact with at least one of an inner ring and an outer ring of the rolling bearing. Deflection scanning device. 2. The optical deflection scanning device according to claim 1, wherein the oil-impregnated member is a pressurized spring or a spring seat for holding the pressurized spring. 3. The light deflection scanning device according to claim 1, wherein the oil-impregnated member is a sleeve that holds the outer ring. 4. A rotary polygon mirror for deflecting and scanning a light beam,
An optical deflection scanning device, comprising: a rolling bearing for rotatably supporting the rotary polygon mirror; and a motor for rotating the rotary polygon mirror, wherein an oil-containing member is in contact with a ball of the rolling bearing. 5. The light deflection scanning device according to claim 4, wherein the oil-impregnated member is a retainer for holding a ball. 6. The light deflection scanning device according to claim 1, wherein the oil-impregnated member is made of an oil-impregnated metal obtained by impregnating a sintered metal with oil. 7. The optical deflection scanning device according to claim 1, wherein the oil-impregnated member is made of an oil-impregnated plastic solidified by dispersing oil in a synthetic resin.