JP2000047131A - Deflection scanning device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the support for a driving magnet of a motor from becoming unstable by a centrifugal force, etc., at the time of high-speed rotation. SOLUTION: A rotary polygon mirror 1 is pressurized by a press spring 8 on the upper face of a flange member 4, and coupled to a driving magnet 5 in one body via the flange member 4. The flange member 4 and the driving magnet 5 are coupled by shrinkage fitting, however sole shrinkage fitting could cause instability of the coupling between the driving magnet 5 and the flange member 4 because the driving magnet 5 is increased in the deformation by a centrifugal force when it is brought into a high temperature state due to self-heating of the motor. Therefore the coupling is reinforced by applying adhesives 9, 10 to both ends of the coupling part of the flange member 4 and the driving magnet 5.

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.

[0002]

2. Description of the Related Art A deflection scanning device used in an image forming apparatus such as a laser beam printer or a laser facsimile irradiates a light beam such as a laser beam onto a reflection surface of a rotary polygon mirror, and performs deflection scanning by high-speed rotation of the rotary polygon mirror. Then, the obtained scanning light is imaged 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.

In recent years, the speed of the deflection scanning device has been increased, and a rotating polygon mirror having a rotation speed exceeding 10,000 rpm has been developed.

FIG. 7 shows a main part of a deflection scanning apparatus according to a conventional example, which comprises a rotating shaft 103 supported by an optical box (not shown) via a ball bearing 102, and an integral part of the rotating shaft 103. A flange member 104, a driving magnet 105 coupled to the flange member 104 by shrink fitting, a stator core 107a fixed to a motor board 106 integrated with a housing 102a of the ball bearing 102, and a stator coil 1 wound therearound.
07b. Rotating polygon mirror 1
01 is pressed against the flange member 104 by the holding spring 108, and the rotary shaft 1 is pressed through the flange member 104.
03 and the drive magnet 105.

When the stator coil 107b is excited by a drive current supplied from a drive circuit on the motor substrate 106, the drive magnet 105 rotates at a high speed together with the rotary polygon mirror 101, and as described above, the rotary polygon mirror 101
Is deflected and scanned by the light beam applied to the.

[0006]

However, according to the above prior art, when the flange member integral with the rotating shaft is connected to the drive magnet by shrink fitting as described above, the stator coil of the motor is excited. When the drive magnet is rotated and driven, the drive magnet is deformed due to the temperature rise inside the image forming apparatus main body and the motor itself due to the self-heating of the motor, and the centrifugal force caused by the high speed rotation, the drive magnet is deformed, and the , The amount of interference of the shrink-fitting portion is reduced, and the contact area between the drive magnet and the flange member is significantly reduced. As a result, there is an unsolved problem that the contact pressure connecting the two becomes small and the connection state becomes unstable.

More specifically, as shown in FIG. 6A, the deformation of the drive magnet due to centrifugal force during high-speed rotation is caused by the rise in temperature of the atmosphere around the motor and the rise of the motor itself due to self-heating of the motor. The deformation is further enhanced by the temperature, and the shrink-fitting portion at the inner diameter portion of the drive magnet is significantly deformed, and the amount of interference between the drive magnet and the flange member is greatly reduced.
Thus, the width B ₀ of the contact area at the shrink-fit portion when rotating at high temperature in a high temperature state is significantly smaller than the width A ₀ when rotating at high speed at room temperature, and the support of the drive magnet is extremely unstable. As a result, the balance of the rotating part deteriorates. When the vibration due to such a deterioration in balance is transmitted through the motor substrate, the housing, and the like, which are the structure of the motor, and the optical box fixing the motor and the optical table supporting the optical box are vibrated. This causes noise, and the deterioration of optical performance due to vibration of optical components such as a return mirror of the scanning optical system.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned unsolved problems of the prior art, and provides a contact area between a driving magnet and a flange member even when a rotary polygon mirror motor is driven at a high temperature under a high temperature. Without significantly decreasing
It is an object of the present invention to provide a high-performance deflection scanning device capable of avoiding noise and vibration caused by deterioration of motor balance and deterioration of optical performance caused by vibration.

[0009]

In order to achieve the above object, a deflection scanning apparatus according to the present invention comprises: a rotary polygon mirror for deflecting and scanning a light beam; a flange member for supporting the rotary polygon mirror; A motor having a coupled driving magnet and a stator opposed thereto, wherein the flange member and the driving magnet are bonded to each other by an adhesive applied to one or both ends of a joint portion between the two. Features.

A rotary polygon mirror for deflecting and scanning the light beam; a flange member for supporting the rotary polygon mirror; a motor having a driving magnet coupled to the flange member and a stator opposed thereto; Wherein the member and the drive magnet are part of an adhesive applied to a contact surface of a joint between the two and are bonded to each other by an adhesive protruding at an end of the joint. It may be a device.

It is preferable that the flange member and the drive magnet are bonded to each other by an adhesive in a recess provided on the contact surface of the connecting portion.

[0012]

[Function] Even if the flange member supporting the rotary polygon mirror and the drive magnet of the motor are joined by a method such as shrink fitting, if the motor is rotated at high speed in a high temperature state due to self-heating of the motor, deformation due to centrifugal force or the like is large. Therefore, it is difficult to maintain a stable connection state because the contact area of the connection portion is small.
Therefore, an adhesive is applied to one or both ends of the joint between the drive magnet and the flange member to enhance the joint force of the joint.

This prevents the contact area between the flange member and the connecting portion of the drive magnet from being remarkably reduced even when the motor is rotated at a high temperature in a high temperature state, thereby preventing the support of the drive magnet from becoming unstable and preventing the motor balance from deteriorating. .

It is possible to realize a stable and high-quality deflection scanning device which does not cause noise or deterioration of optical performance due to vibration due to deterioration of motor balance.

The motor further includes a rotary polygon mirror for deflecting and scanning the light beam, a flange member for supporting the rotary polygon mirror, a motor having a driving magnet coupled to the flange member, and a stator opposed thereto. The flange member and the drive magnet are part of an adhesive applied to an abutting surface of a joint between the two, and are bonded to each other by an adhesive protruding at an end of the joint. In the case of a deflection scanning device, before bonding the drive magnet and the flange member, apply an appropriate amount of adhesive to the contact surface between them, and use the adhesive that has protruded from the connection part in a process such as shrink fitting. Therefore, the advantages of greatly simplifying the application and curing steps of the adhesive and reducing the assembly cost are added.

Further, if the flange member and the driving magnet are bonded to each other by the adhesive of the recess provided on the contact surface of the connecting portion, the flange member and the driving magnet are further strengthened by the adhesive of the recess. There is an advantage that can be combined.

[0017]

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

FIG. 1 shows a main part of a deflection scanning apparatus according to a first embodiment, which comprises a rotary polygon mirror 1 having a plurality of reflecting surfaces 1a on a polygonal column-shaped side surface, and an optical box 50 described later. (See FIG. 4), a rotating shaft 3 supported via a ball bearing 2, a driving magnet 5 integrally connected to the rotating shaft 3 via a flange member 4 fixed to the rotating shaft 3, and a ball. Housing 2 for supporting bearing 2
a, a stator core 7a erected on a motor substrate 6 on the housing 2a, and a stator coil 7 wound therearound.
b, which constitutes an inner rotor type motor which faces the drive magnet 5 and rotates the rotary polygon mirror 1 together therewith. The rotary polygon mirror 1 is pressed against the flange member 4 by the holding spring 8 and is integrated with the drive magnet 5 via the flange member 4.

When the stator coil 7b is excited by the drive current supplied from the drive circuit on the motor board 6,
The drive magnet 5 rotates together with the rotating shaft 3 and the rotating polygon mirror 1, and deflects and scans a light beam such as a laser beam applied to the reflection surface 1a of the rotating polygon mirror 1.

The stator core 7a is fastened to the motor substrate 6 by a known means such as a screw, and a stator coil 7b is wound around teeth on the inner periphery of the stator core 7a.

The flange member 4 and the drive magnet 5 are integrally joined by shrink fitting. Adhesives 9 and 10, which are anaerobic ultraviolet curing adhesives, are applied to both ends of the joint by shrink fitting. Thereby, the flange member 4
And the drive magnet 5 are adhered to each other. That is, the large diameter portion of the flange member 4 and the upper surface of the drive magnet 5 are adhered by the adhesive 9 applied in a ring shape along the outer periphery of the flange member 4, and the small diameter portion (boss portion) of the flange member 4. The inner diameter of the drive magnet is bonded to the lower surface of the flange member 4 by an adhesive 10 applied in a ring shape.

These adhesives 9 and 10 are applied to the above-mentioned portions after the drive magnet 5 is shrink-fitted to the flange member 4 and are cured by irradiation with ultraviolet rays. As shown in FIG. 1B, the irradiation of the ultraviolet rays is performed by assembling the upper adhesive 9 from above in the drawing before attaching the rotary polygon mirror 1 and the lower adhesive 10 by assembling the rotating shaft 3 to the ball bearing 2. This is performed before from below in the figure.

If the flange member 4 and the drive magnet 5 are simply joined by shrink fitting, as in the conventional example shown in FIG. 6A, the motor of the rotary polygon mirror 1 generates heat and the temperature inside the image forming apparatus increases. When deformation due to centrifugal force or the like is promoted when rotating at a high temperature in a high temperature state, the contact area for obtaining the contact pressure of the joint by shrink fitting becomes small. As a result, the support state of the drive magnet 5 becomes unstable, and the balance of the motor is deteriorated. Due to the vibration, troubles such as noise and optical performance deterioration of the folding mirror 53 described later occur. In order to avoid such troubles, both ends of the joint portion between the flange member 4 and the drive magnet 5 by shrink fitting are adhered by the adhesives 9 and 10 applied in a ring shape to enhance the joint force of the joint portion. Thus, even when the high-speed rotation is performed in a high temperature state, the coupling portion between the flange member 4 and the driving magnet 5 can be maintained in a stable coupling state without separating.

In this way, if the coupling of the coupling portion by shrink fitting between the flange member and the drive magnet is strengthened,
As shown in FIG. 6B, even when the motor is rotated at a high speed in a high temperature state, the width B ₁ of the contact area of the joint is almost the same as the width A ₁ when the motor is rotated at a high speed at room temperature. A sufficient contact pressure can be maintained.

By avoiding deterioration of the motor balance due to insufficient coupling of the shrink-fitting portion at high temperatures, a high-quality deflection scanning device with little vibration and noise and excellent optical performance can be realized. .

Although this embodiment employs an inner rotor type motor in which a driving magnet is disposed facing the inner peripheral side of the stator core, an outer rotor in which the stator core is disposed inside the driving magnet is used. The same applies to motors of the type. In the outer rotor type motor, the outer diameter of the drive magnet tends to increase, so that the centrifugal force during high-speed rotation further increases. Therefore, it can be said that the application of the present invention is particularly effective.

Although the adhesive is applied to both ends of the joint between the drive magnet and the flange member in a ring shape, the adhesive may be applied to only one of the upper and lower ends of the joint in some cases. Instead of bonding the entire circumference in a ring shape, the adhesive may be applied partially, that is, intermittently.

FIG. 2 shows a second embodiment. this is,
When the drive magnet 25 is joined to the flange member 24 by shrink fitting, as shown in FIG. 2A, a contact surface on the flange member 24 side or a contact surface on the drive magnet 25 side in the joint portion before assembly. A predetermined amount of adhesive 29a or 29b is applied to the contact surface. When the drive magnet 25 is shrink-fitted to the flange member 24, the adhesive 29a or 29b is pushed out from the joint between the drive magnet 25 and the flange member 24, as shown in FIG. Thus, the adhesive 30 protruding to the end of the joint portion
By hardening, the bonding of the bonding portion by shrink fitting is strengthened.

The adhesive is an anaerobic UV-curable adhesive as in the first embodiment, and is cured by irradiation with ultraviolet rays. The rotating polygon mirror 1, the rotating shaft 3, the holding spring 8 and the like are the same as those in the first embodiment, and are represented by the same reference numerals, and description thereof is omitted. FIG. 2 shows a state in which the rotary polygon mirror 1 is already mounted.
Before the rotary polygon mirror 1 is attached, the adhesive 30 is cured by ultraviolet irradiation from above in the figure.

The contact area where the contact pressure is generated between the drive magnet 25 and the flange member 24 is determined by the contact area of the joint between the drive magnet 25 and the flange member 24 even under the condition that a high temperature state is applied to the high-speed rotation drive. Since the bonding portion is adhered by the adhesive 30 protruding to the end, a stable bonding state can be maintained without being greatly reduced. As a result, it is possible to realize an extremely high-performance deflection scanning device in which noise and vibration due to deterioration of the motor balance and deterioration of optical performance due to vibration are small.

In addition, since the step of applying an adhesive for strengthening the connection between the drive magnet and the flange member and the step of curing the adhesive are simple, there is an advantage that the assembly cost is reduced. Other points are the same as those of the first embodiment.

FIG. 3 shows a third embodiment together with its modification.

The apparatus shown in FIG.
An annular recess 40 serving as an adhesive reservoir facing the connecting portion of the drive magnet 35 and the driving magnet 35 is provided on the contact surface of the flange member 34, and a similar recess 41 is formed as shown in FIG. It may be provided on the contact surface on the drive magnet 35 side. Also,
Similar recesses 42 and 43 are formed in the lower surface (contact surface) of the flange member 34 as shown in FIG. 3C or the upper surface (contact surface) of the drive magnet 35 as shown in FIG. ) May be provided.

Since the rotary polygon mirror 1 and the rotary shaft 3 are the same as those in the first embodiment, they are denoted by the same reference numerals, and description thereof is omitted.

The number of the recesses serving as the adhesive pool is not limited to one. For example, the contact surface between the drive magnet and the flange portion of the flange member, or the contact surface between the drive magnet and the boss portion of the flange member. May be provided in two places.

In the apparatus shown in FIGS. 3 (a) to 3 (d), when the drive magnet 35 is shrink-fitted to the flange member 34 and bonded to the recesses 40 to 43 which will be adhesive reservoirs before assembly. After the agent 49a is attached, the drive magnet 35 is assembled to the flange member 34 by shrink fitting. At this time, a part of the adhesive 49a is sealed in the recesses 40 to 43, which are adhesive pools, and hardens in the recesses 40 to 43 due to anaerobic property. A part of the adhesive 49b is extruded from the end of the joint between the drive magnet 35 and the flange member 34, and the protruding adhesive 49b is cured by irradiation with ultraviolet rays.

The adhesive 49a in the adhesive pool, together with the adhesive 49b protruding from the joint portion, serves to strengthen the joint by shrink fitting between the drive magnet 35 and the flange member 34. That is, compared to the first and second embodiments, since the adhesive force of the adhesive 49a of the adhesive pool is added, the effect of strengthening the connection is further enhanced, and the deformation of the drive magnet 35 is prevented. There is an advantage that reliability is improved. The other points are the same as in the first embodiment.

FIG. 4 shows the entire deflection scanning device, which is a light source 5 for generating a light beam (light flux) such as a laser beam.
1 and a cylindrical lens 51a for linearly condensing the light beam on the reflection surface 1a of the rotary polygon mirror 1, and deflects and scans the light beam by the rotation of the rotary polygon mirror 1.
An image is formed on a photoreceptor 54 on a rotating drum shown in FIG. 5 via an imaging lens 52 and a folding mirror 53. Imaging lens 5
Reference numeral 2 includes a spherical lens unit, a toric lens unit, and the like, and has a so-called fθ function of correcting a scanning speed of a point image formed on the photoconductor 54.

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 54 moves (scans) in the axial direction (main scanning direction) of the rotating drum.

The imaging lens 52 condenses the light beam reflected by the rotary polygon mirror 1 on the photosensitive member 54 into a point image having a predetermined spot shape, and also controls the scanning speed of the point image in the main scanning direction. It is designed to keep constant speed.

The point image formed on the photoreceptor 54 is formed as an electrostatic latent image by the main scanning by the rotation of the rotary polygon mirror 1 and the sub-scanning by the rotation of the photoreceptor 54 about the axis of the rotating drum. To form

Around the photosensitive member 54, a charging device for uniformly charging the surface of the photosensitive member 54, and a charging device for visualizing an electrostatic latent image formed on the surface of the photosensitive member 54 into a toner image. A developing device, a transfer device (not shown) 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 55 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 54, and receives a light receiving element 56 having a photodiode or the like. To the light receiving surface of The light receiving element 56 outputs a scan start signal for detecting a scan 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 a host computer. The signal given to the light source 51 corresponds to information to be written on the photoconductor 54, 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 54. The signal is given to the light source 51 as one unit. This information signal is transmitted in synchronization with a scanning start signal given from the light receiving element 56.

The rotary polygon mirror 1, the imaging lens 52 and the like are housed in an optical box 50, and the light source 51 and the like are mounted on the side wall of the optical box 50. After assembling the rotary polygon mirror 1, the imaging lens 52, and the like to the optical box 50, the lid 60 is attached to the upper opening of the optical box 50.

[0046]

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

When the rotating polygon mirror is rotated at a high speed, the coupling between the driving magnet and the flange member becomes unstable and the motor balance is prevented from deteriorating, and there is little trouble such as deterioration of optical performance due to noise or vibration. A high performance deflection scanning device can be realized.

[Brief description of the drawings]

FIGS. 1A and 1B show a main part of a deflection scanning apparatus according to a first embodiment, in which FIG. 1A is a schematic partial cross-sectional view, and FIG. 1B is a view for explaining a step of curing an adhesive.

FIGS. 2A and 2B show a main part of a deflection scanning device according to a second embodiment, in which FIG. 2A is a schematic partial sectional view showing a state before a driving magnet is assembled, and FIG. 2B is a state after the driving magnet is assembled. It is the same figure which shows the state of.

FIG. 3 is a diagram showing a third embodiment together with its modified example.

FIG. 4 is a diagram illustrating the entire deflection scanning device.

FIG. 5 is a sectional view taken along line AA of FIG. 4;

FIG. 6 is a diagram comparing the deformation of the drive magnet when the motor is rotated at a high speed at a high temperature and when the motor is rotated at a high speed at a normal temperature.

FIG. 7 is a schematic partial sectional view showing a conventional example.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 rotating polygon mirror 3 rotating shaft 4, 24, 34 flange member 5, 25, 35 drive magnet 6 motor substrate 7 stator 7a stator core 7b stator coil 8 holding spring 9, 10, 30, 49a, 49b adhesive 40-43 recess 50 optical box

Claims (4)

[Claims] A rotary polygon mirror for deflecting and scanning a light beam;
A flange member for supporting the rotary polygon mirror, a motor having a driving magnet coupled to the flange member and a stator opposed thereto are provided, and the flange member and the driving magnet are provided at one end of a joint between the two. A deflection scanning device, which is adhered to each other by an adhesive applied to both ends. 2. A rotary polygon mirror for deflecting and scanning a light beam,
A motor having a flange member for supporting the rotary polygon mirror, a driving magnet coupled to the flange member, and a stator facing the flange member, wherein the flange member and the driving magnet are in contact with each other at a joint between the two. A deflection scanning device, wherein a part of the adhesive applied to the surfaces is adhered to each other by an adhesive protruding at an end of the joint. 3. The deflection scanning device according to claim 1, wherein the flange member and the driving magnet are bonded to each other by an adhesive in a recess provided on the contact surface of the connecting portion. 4. The drive magnet according to claim 1, wherein the drive magnet is coupled to the flange member by shrink fitting.
4. The deflection scanning device according to any one of claims 1 to 3.