JP2004286967A - Optical scanner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical scanner capable of efficiently dissipating heat of a polygon motor arranged inside an optic box to the outside of the optic box without decreasing rigidity of the optic box. <P>SOLUTION: A bearing sleeve 24 of the polygon motor 42 is inserted in a through-hole 54 formed in a bottom plate 50 of the optic box 32. A male screw 58 of a bearing fixing member 30 made of a metal or the like located outside the optic box 32 is engaged in a female screw formed in the bearing sleeve 24 and thereby the polygon motor 42 is fixed to the optic box 32. Since the heat of the polygon motor 42 is dissipated outside the optic box 32 by being transmitted from the bearing sleeve 24 via the bearing fixing member 30 of a metal having higher thermal conductivity than the optic box 32, a temperature rise in the optic box 32 can remarkably be decreased. Moreover, since there is no large opening part for heat dissipation in the bottom plate 50 of the optic box 32, the optic box 32 is not decreased in rigidity. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an optical scanning device using a rotating polygon mirror, for example, an optical scanning device for scanning a laser beam onto an image carrier in a laser beam printer or the like.
[0002]
[Prior art]
FIG. 8 shows a conventional optical scanning device 100 used in a laser beam printer (for example, see Patent Document 1).
[0003]
8, reference numeral 102 denotes a polygon mirror (rotating polygon mirror), 104 denotes a polygon mirror holder, 106 denotes a polygon mirror base, 108 denotes a rotation driving magnet, 110 denotes a rotating body support member, 112 denotes a rotating shaft, 114 denotes a bearing sleeve, 116 is a stator coil, 118 is a rotation drive board unit, 120 is a motor fixing screw, and 122 is an optical box.
[0004]
In the figure, the polygon mirror 102 is sandwiched between a polygon mirror holder 104 and a polygon mirror pedestal 106, and the polygon mirror pedestal 106 and the rotating shaft 112 are fixed to a rotating member supporting member 110 to which a rotation driving magnet 108 is fixed (see FIG. 1). Hereinafter, the entirety of the reference numerals 102 to 118 is referred to as a rotor 124.)
[0005]
The rotating shaft 112 is inserted into a bearing sleeve 114, and the rotor 124 is rotatable with respect to the bearing sleeve 114.
[0006]
Further, the stator coil 116 is fixed to the rotary drive board unit 118, the rotary drive board unit 118 is fixed to the bearing sleeve 114, and the rotary drive board unit 118 is fixed to the optical box 122 by a motor fixing screw 120 or the like.
[0007]
The entire rotation mechanism for rotating the polygon mirror 102, which includes the bearing sleeve 114, the stator coil 116, the rotation drive board unit 118, the rotor 124, and the like, is hereinafter referred to as a polygon motor 126.
[0008]
Next, the operation of the conventional optical scanning device will be described.
[0009]
When a start signal is input to a motor drive circuit (not shown) on the rotary drive board unit 118, the stator coil 116 is energized in a predetermined order.
[0010]
Then, a rotating torque is generated in the rotor 124 by an electromagnetic force acting between the stator coil 116 and the rotation driving magnet 108, and the rotor 124 rotates around the rotation shaft 112.
[0011]
At this time, the motor drive circuit adjusts the amount of current flowing through the stator coil 116 in accordance with the rotation speed of the rotor 124, and performs control so that the rotation speed of the rotor 124 always becomes the set rotation speed.
[0012]
At this time, scanning light is obtained by irradiating the polygon mirror 102 with laser light (not shown) and reflecting and deflecting it.
[0013]
[Problems to be solved by the invention]
In the above conventional example, the entire polygon motor 126 is fastened to the optical box 122 by screw fastening holes drilled at four corners of the rotary drive board unit 118.
[0014]
Therefore, when the temperature inside the optical box 122 rises due to heat generated by the polygon motor 126 and the like, the optical box 122 and the rotary drive board unit 118 are bent due to a difference in the thermal expansion coefficient between the rotary drive board unit 118 and the optical box 122. (For example, the bottom plate of the optical box 122 is convexly curved downward). As a result, there is a problem that the bearing sleeve 114 is deviated from a designed correct position, or falls down. (Note that the arrow in FIG. 8 indicates the deformation direction of the member.)
[0015]
If the position of the bearing sleeve 114 shifts or falls, the polygon mirror 102 also rotates at a position deviated from the designed position, so that the laser beam is not scanned to the correct position on the image carrier. And the correct image will not be output.
[0016]
As a solution to such a problem, (1) the interval between the points at which the polygon motor 126 and the optical box 122 are fixed is made as short as possible. (2) The heat generated by the polygon motor 126 is radiated to the outside of the optical box 122. It has been considered effective to suppress the temperature rise inside the optical box 122 as much as possible.
[0017]
However, since the motor drive circuit components, the stator coil 116, and their wiring patterns are present on the rotary drive board unit 118, it is difficult to arrange the mounting screw holes close enough to obtain a sufficient effect. there were.
[0018]
Further, as an approach of dissipating the heat generated by the polygon motor 126 to the outside of the optical box 122, as shown in FIG. 9, a large opening 128 is provided in the bottom plate of the optical box 122 to expose the rotary drive board unit 118 to the outside air. Further, heat is radiated by exposing a radiator 130 attached to the rotary drive board unit 118 through a large opening 128 (see, for example, Patent Document 2).
[0019]
However, providing such a large opening 128 in the optical box 122 makes it impossible to obtain a simple structure as shown in FIG. There was a problem that the design of the optical box 122 became more difficult, such as a decrease in the rigidity of the box 122 (the arrows in FIG. 9 indicate the direction of deformation of the member).
[0020]
Further, usually, the optical box 122 needs to be completely sealed so that fine dust from the outside does not enter. The large opening 128 is disadvantageous also in this regard.
[0021]
[Patent Document 1]
JP-A-6-75184
[Patent Document 2]
JP-A-11-160644
[0022]
In view of the above, the present invention provides an optical scanning device capable of efficiently dissipating heat of a polygon motor provided inside an optical box to the outside of the optical box without reducing the rigidity of the optical box. Is the purpose.
[0023]
[Means for Solving the Problems]
The optical scanning device according to claim 1, wherein the light source emits a light beam, a rotating polygon mirror for deflecting and scanning the light beam, a rotating shaft connected to the rotating polygon mirror, and a rotating shaft connected to the rotating shaft. A rotating drive magnet, a bearing for inserting the rotating shaft from one end in the axial direction and rotatably holding the rotating shaft, and a rotating drive board unit having a stator coil connected to the bearing for rotating the rotating body. A polygon motor, an optical system that forms an image of the light beam on the surface to be scanned, an optical box that houses the light source, the polygon motor, and the optical system, and an axial other end of the bearing. An engaging portion, a through hole provided in the optical box, for inserting a part of the other end side of the bearing from the inside of the optical box, at least a part of the through hole is arranged outside the optical box, By engaging the engagement portion of the bearing from parts, it is characterized by having a bearing fixing member for positioning and fixing the polygon motor in the optical box.
[0024]
Next, the operation of the optical scanning device according to the first aspect will be described.
[0025]
According to the optical scanning device of the first aspect, in the bearing of the polygon motor, a part on the other end side of the bearing is inserted into the through hole from the inside of the optical box, and the bearing fixing member disposed outside the optical box is provided. The polygon motor is positioned and fixed to the optical box by engaging with the engaging portion of the bearing.
[0026]
Therefore, the polygon motor can be fixed to the optical box at a single point with a simple structure without providing a large opening in the optical box, and at the same time, the heat generated by the polygon motor is transmitted through the bearing and the bearing fixing member. Since the heat is efficiently radiated to the outside of the optical box, the temperature rise of the optical box can be reduced, and the optical box and the rotational drive substrate unit are bent (occurs when the optical expansion coefficient of the optical box and the rotational drive substrate unit are different). Accordingly, it is possible to prevent a problem that the light beam is not correctly scanned on the image carrier.
[0027]
The light beam emitted from the light source is deflected and scanned by a rotating polygon mirror rotated by a polygon motor, and is imaged on a surface to be scanned by an optical system.
[0028]
According to a second aspect of the present invention, in the optical scanning device according to the first aspect, the engaging portion of the bearing is a concave portion, and the bearing and the bearing are fixed by pressing a part of the bearing fixing member into the concave portion. The bearing fixing member is fixed.
[0029]
Next, the operation of the optical scanning device according to the second aspect will be described.
[0030]
In the optical scanning device according to the second aspect, the bearing and the bearing fixing member are fixed by partially press-fitting the bearing fixing member into the recess of the bearing.
[0031]
According to a third aspect of the present invention, in the optical scanning device according to the first aspect, the engaging portion of the bearing is a concave portion, and a part of the bearing fixing member is inserted and adhered to the concave portion to form a contact with the bearing. The bearing fixing member is fixed.
[0032]
Next, the operation of the optical scanning device according to the third aspect will be described.
[0033]
In the optical scanning device according to the third aspect, the bearing and the bearing fixing member are fixed by inserting and bonding a part of the bearing fixing member into the recess of the bearing.
[0034]
According to a fourth aspect of the present invention, in the optical scanning device according to the first aspect, the engaging portion of the bearing is a hole provided with a first spiral groove on an inner surface, and the outer portion of the bearing fixing member. A second spiral groove is provided on the side surface,
The bearing and the bearing fixing member are fixed by screwing the first spiral groove and the second spiral groove.
[0035]
Next, the operation of the optical scanning device according to the fourth aspect will be described.
[0036]
In the optical scanning device according to the fourth aspect, the bearing and the bearing fixing member are fixed by the second helical groove provided in the bearing fixing member screwing into the first helical groove provided in the hole of the bearing. Is done.
[0037]
An optical scanning device according to claim 5, wherein the light source emits a light beam, a rotating polygon mirror for deflecting and scanning the light beam, a rotating shaft connected to the rotating polygon mirror, and a rotating shaft connected to the rotating shaft. A rotating drive magnet, a bearing for inserting the rotating shaft from one end in the axial direction and rotatably holding the rotating shaft, and a rotating drive board unit having a stator coil connected to the bearing for rotating the rotating body. A polygon motor, an optical system that forms an image of the light beam on the surface to be scanned, an optical box that houses the light source, the polygon motor, and the optical system, and one end that is integrally connected to the bearing. A bearing support member having an engaging portion, a through hole provided in the optical box, for inserting a part of the bearing support member from the inside of the optical box, and at least a part disposed outside the optical box. It is, by engaging the engagement portion of the bearing support member from the outside of the optical box, is characterized by having a bearing fixing member for positioning and fixing the polygon motor in the optical box.
[0038]
Next, the operation of the optical scanning device according to the fifth aspect will be described.
[0039]
According to the optical scanning device of the fifth aspect, the bearing of the polygon motor is integrally connected to the bearing support member.
[0040]
A bearing support member connected to the polygon motor is inserted into the through-hole from the inside of the optical box, and a bearing fixing member arranged outside the optical box engages with an engagement portion of the bearing support member, so that the polygon motor can receive a bearing. It is positioned and fixed to the optical box via the support member.
[0041]
Therefore, the polygon motor can be fixed to the optical box at a single point with a simple structure without providing a large opening in the optical box. At the same time, the heat generated by the polygon motor is transferred to the bearing, the bearing support member, and the bearing. Since the heat is efficiently radiated to the outside of the optical box via the fixing member, the temperature rise of the optical box can be reduced, and the optical box and the rotation drive board unit are bent (the optical box and the rotation drive board unit have different thermal expansion coefficients. Can be prevented from being incorrectly scanned by the light beam on the image carrier.
[0042]
The light beam emitted from the light source is deflected and scanned by a rotating polygon mirror rotated by a polygon motor, and is imaged on a surface to be scanned by an optical system.
[0043]
According to a sixth aspect of the present invention, in the optical scanning device according to the fifth aspect, the engagement portion of the bearing support member is a concave portion, and the bearing is formed by press-fitting a part of the bearing fixing member into the concave portion. A support member and the bearing fixing member are fixed.
[0044]
Next, the operation of the optical scanning device according to claim 6 will be described.
[0045]
In the optical scanning device according to the sixth aspect, the bearing supporting member and the bearing fixing member are fixed by partially press-fitting the bearing fixing member into the concave portion of the bearing supporting member.
[0046]
According to a seventh aspect of the present invention, in the optical scanning device according to the fifth aspect, the engaging portion of the bearing support member is a concave portion, and a part of the bearing fixing member is inserted and adhered to the concave portion. The bearing support member and the bearing fixing member are fixed.
[0047]
Next, the operation of the optical scanning device according to claim 7 will be described.
[0048]
In the optical scanning device according to the seventh aspect, the bearing support member and the bearing fixing member are fixed by inserting a part of the bearing fixing member into the concave portion of the bearing support member and bonding it.
[0049]
The invention according to claim 8 is the optical scanning device according to claim 5, wherein the engagement portion of the bearing support member is a hole provided with a first spiral groove on an inner surface, and the bearing fixing member. A second helical groove is provided on an outer surface of the bearing, and the bearing support member and the bearing fixing member are fixed by screwing the first helical groove and the second helical groove. Is characterized by the fact that
[0050]
Next, the operation of the optical scanning device according to claim 8 will be described.
[0051]
In the optical scanning device according to the eighth aspect, the first helical groove provided in the hole of the bearing support member is screwed with the second helical groove provided in the bearing fixing member to fix the bearing support member and the bearing. The member is fixed.
[0052]
According to a ninth aspect of the present invention, in the optical scanning device according to any one of the first to eighth aspects, the bearing fixing member and the optical box are disposed between the bearing fixing member and the optical box. An elastic member that generates a repulsive force is disposed between the elastic members.
[0053]
Next, the operation of the optical scanning device according to the ninth aspect will be described.
[0054]
Since an elastic member that generates a repulsive force is arranged between the bearing fixing member and the optical box between the bearing fixing member and the optical box, a force is generated in a direction in which the bearing fixing member is separated from the optical box. The entire motor is pressed and fixed inside the optical box.
[0055]
According to a tenth aspect of the present invention, in the optical scanning device according to any one of the first to ninth aspects, when the bearing fixing member and the bearing are engaged, the bearing fixing member and the bearing A part or all of the bearing fixing member is made of an elastic material so as to have a repulsive force between the bearing box and the optical box.
[0056]
Next, the operation of the optical scanning device according to the tenth aspect will be described.
[0057]
When the bearing fixing member and the bearing engage, a repulsive force is generated between the bearing fixing member and the optical box due to the elastic force of the elastic material constituting the bearing fixing member, and the polygon motor is pressed against the inside of the optical box. Is fixed.
[0058]
According to an eleventh aspect of the present invention, in the optical scanning device according to any one of the first to tenth aspects, a part or all of the bearing fixing member has a higher thermal conductivity than the optical box. It is characterized by being composed of a material.
[0059]
Next, the operation of the optical scanning device according to the eleventh aspect will be described.
[0060]
By configuring a part or all of the bearing fixing member with a material having higher thermal conductivity than the optical box, heat generated by the polygon motor is more efficiently transmitted to the outside of the optical box via the bearing fixing member. Will be able to do it.
[0061]
BEST MODE FOR CARRYING OUT THE INVENTION
[First Embodiment]
FIG. 1 is a sectional view showing an optical scanning device 10 according to a first embodiment of the present invention.
[0062]
1, reference numeral 12 denotes a polygon mirror, reference numeral 14 denotes a polygon mirror holder, reference numeral 16 denotes a polygon mirror base, reference numeral 18 denotes a rotation driving magnet, reference numeral 20 denotes a rotating body support member, reference numeral 22 denotes a rotating shaft, and reference numeral 24 denotes a bearing. Reference numeral 26 denotes a stator coil, reference numeral 27 denotes a yoke for mounting the stator coil 26, reference numeral 28 denotes a rotary drive board unit, reference numeral 30 denotes a bearing fixing member, and reference numeral 32 denotes an optical box.
[0063]
The optical box 32 of the present embodiment is formed of a synthetic resin.
[0064]
The polygon mirror holder 14, the polygon mirror pedestal 16, and the rotating body support member 20 are fixed to a rotating shaft 22.
[0065]
The polygon mirror 12 is located between the polygon mirror holder 14 and the polygon mirror pedestal 16, and is held by the elastic force of the polygon mirror holder 14.
[0066]
Further, the rotation driving magnet 18 is fixed to the rotating body support member 20.
[0067]
Hereinafter, the entire rotating body portion including the polygon mirror 12, the polygon mirror retainer 14, the polygon mirror pedestal 16, the rotation driving magnet 18, the rotating body support member 20, the rotating shaft 22, and the like will be referred to as a rotor 34.
[0068]
The yoke 27 to which the stator coil 26 is attached is fixed to the rotary drive board unit 28.
[0069]
The bearing sleeve 24 has a large diameter portion 24A formed with a large diameter on the upper side, and a small diameter portion 24B formed with a small diameter on the lower side.
[0070]
Although the bearing sleeve 24 of the present embodiment is made of brass, it can be formed of a metal other than brass or another material.
[0071]
The small-diameter portion 24 </ b> B of the bearing sleeve 24 passes through a hole 36 formed in the rotary drive board unit 28.
[0072]
An annular groove 38 is formed in the small-diameter portion 24B protruding below the rotary drive board unit 28, and the rotary drive board is disposed between the ring 40 fitted in the groove 38 and the lower end surface of the large-diameter portion 24A. A unit 28 is located.
[0073]
The entire rotation mechanism for rotating the polygon mirror 12 is constituted by the bearing sleeve 24, the stator coil 26, the yoke 27, the rotary drive board unit 28, the rotor 34, and the like, and is hereinafter referred to as a polygon motor 42.
[0074]
The bearing sleeve 24 has a hole 44 on the upper side for rotatably inserting the rotary shaft 22 of the rotor 34, and a large-diameter hole 46 having a large diameter opening on the lower end below the hole 44. ing.
[0075]
A thrust plate 48 that supports the rotating shaft 22 is fixed near the lower end of the hole 44.
[0076]
The small-diameter portion 24B of the bearing sleeve 24 is inserted into a through hole 54 formed in the boss 52 of the bottom plate 50 of the optical box 32, and serves to position the polygon motor 42 in the horizontal direction with respect to the optical box 32 and to rotate the polygon motor 42 in the rotation axis direction (rotational direction). The angle is determined.
[0077]
Therefore, the inner diameter of the through hole 54 is only slightly larger than the outer diameter of the small diameter portion 24 </ b> B of the bearing sleeve 24.
[0078]
A female screw (not shown) is formed in the large diameter hole 46 of the bearing sleeve 24.
[0079]
The bearing fixing member 30 is formed of a member having higher thermal conductivity than the optical box 32, and has a cylindrical portion 60 on which a male screw 58 is screwed with a female screw of the bearing sleeve 24, and a radial direction from the cylindrical portion 60. And a plurality of radial projections 62 extending therefrom.
[0080]
The material for forming the bearing fixing member 30 may be a metal such as brass, steel, stainless steel, or aluminum. If the material has a higher thermal conductivity than at least the optical box 32, a material other than a metal such as ceramics is used. It may be.
[0081]
The radial projection 62 is formed in a leaf spring shape having elasticity.
[0082]
The male screw 58 of the bearing fixing member 30 is screwed into the female screw of the bearing sleeve 24 from outside the optical box 32.
[0083]
The radial projections 62 of the bearing fixing member 30 are elastically deformed when their distal ends are pressed against the bottom plate 50 of the optical box 32, and generate a force in a direction to separate the bearing fixing member 30 from the optical box 32.
[0084]
For this reason, the polygon motor 42 is fixed by pulling the bearing sleeve 24 downward and pressing the large-diameter portion 24 </ b> A of the bearing sleeve 24 against the boss 52 of the optical box 32 with the rotary drive board unit 28.
[0085]
The rotation drive board unit 28 is fixed to the optical box 32 only at one point of the boss 52.
[0086]
FIG. 2 shows an outline of the internal configuration of the optical scanning device 10.
[0087]
As shown in FIG. 2, inside the optical box 32, a light source 74 for emitting laser light, optical lenses 76 and 78, an optical mirror 80, and the like are mounted in addition to the polygon mirror 12 and the polygon motor 42.
[0088]
In the optical scanning device 10, the laser light emitted from the light source 74 is deflected by the polygon mirror 12, and scans and exposes the surface of a photosensitive drum 82 to be described later via an optical lens 76 and an optical mirror 80. .
[0089]
As shown in FIG. 3, in the image forming apparatus 84 including the optical scanning device 10, the photosensitive drum 82 disposed below the optical scanning device 10 rotates at a predetermined angular velocity in the direction of arrow Q in FIG. .
[0090]
In the vicinity of the outer peripheral portion of the photosensitive drum 82, a charging device 86, a developing device 88, a transfer device 90, and a cleaning device 92 are sequentially installed along the outer periphery.
[0091]
The scanning position of the laser beam by the optical scanning device 10 is set between the charging position by the charging device 86 and the developing position by the developing device 88.
[0092]
The surface of the photosensitive drum 82 charged by the charging device 86 is scanned and exposed by laser light from the optical scanning device 10 modulated according to digital image data, and an electrostatic latent image is formed.
[0093]
Further, the electrostatic latent image is developed by the developing device 88, and a toner image corresponding to the electrostatic latent image is formed on the surface of the photosensitive drum 82.
[0094]
On the other hand, the sheet P is conveyed along a predetermined path to a nip portion between the photosensitive drum 82 and the transfer device 90 in synchronization with the formation of the toner image.
[0095]
A predetermined transfer bias voltage is applied to the transfer device 90 at the timing when the sheet P is conveyed to the nip portion, and the application of the transfer bias voltage and the pressing action of the transfer device 90 on the photoconductor drum 82 of the sheet P The toner image on the drum 82 is transferred to the paper P.
[0096]
The sheet P after the transfer is conveyed to the fixing device 94, and the toner image formed on the sheet P is fixed on the sheet P.
[0097]
The fixed sheet P is conveyed in the direction of arrow W and discharged to a discharge tray (not shown).
(Action)
Next, the operation of the optical scanning device 10 of the present embodiment will be described.
[0098]
In the optical scanning device 10 of the present embodiment, heat generated by the polygon motor 42 is transmitted from the bearing sleeve 24 to the metal bearing fixing member 30 having a higher thermal conductivity than the optical box 32, and the surface of the bearing fixing member outside the optical box 32. In particular, since a large amount of heat is radiated from the surface of the radial projections 62 to the outside of the optical box 32, the temperature rise inside the optical box 32 can be extremely reduced.
[0099]
In addition, the inner diameter of the through hole 54 formed in the bottom plate 50 of the optical box 32 may be equal to or less than the outer diameter of the bearing sleeve 24, and the bottom plate 50 of the optical box 32 may have a large opening for heat dissipation described in the related art. Since it is not necessary, the rigidity of the optical box 32 does not decrease.
[0100]
Further, the measure for dustproofing the optical box 32 only needs to seal the through hole 54 of the optical box 32, which is much easier than sealing a large opening.
[0101]
Further, in the optical scanning device 10 of the present embodiment, since the polygon motor 42 is fixed to the optical box 32 only in the vicinity of the bearing sleeve 24, the temperature inside the optical box 32 rises, and the rotation drive board unit 28 and the optical box 32 The deformation of the optical box 32 due to the difference in thermal expansion coefficient from the optical box 32 does not occur, and there is no problem that the bearing sleeve 24 is deviated from the designed correct position or falls down.
[0102]
Therefore, the light beam can be optimally scanned at a predetermined position on the photosensitive drum 82.
[0103]
Further, since the bearing sleeve 24 is positioned relative to the optical box 32 by a simple structure in which the bearing sleeve 24 and the through hole 54 are fitted, the design of the optical box 32 is easy and the cost is advantageous.
[0104]
As described above, the heat of the polygon motor 42 is radiated to the outside through the through-hole 54 formed in the optical box 32. However, it is preferable that the area for radiating the heat outside the optical box 32 is large.
[0105]
Here, the area for radiating heat outside the optical box 32 is preferably three times or more the cross-sectional area of the through hole 54. That is, the surface area of the bearing fixing member 30 outside the optical box 32 is preferably three times or more the cross-sectional area of the through hole 54.
[0106]
In the present embodiment, the male screw 58 of the bearing fixing member 30 is screwed into a female screw (not shown) of the bearing sleeve 24 to fix the bearing fixing member 30 and the bearing sleeve 24. As shown in FIG. 7, the bearing fixing member 30 may be press-fitted into the bearing sleeve 24 without forming the male screw 58 and the female screw, or the bearing fixing member 30 and the bearing sleeve 24 may be fixed using an adhesive.
[Second embodiment]
Next, an optical scanning device 10 according to a second embodiment of the present invention will be described with reference to FIG. The same components as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.
[0107]
As shown in FIG. 5, in the present embodiment, the bearing sleeve 24 is inserted into a member having a higher thermal conductivity than the optical box 32, in this embodiment, a bearing support member 64 made of metal.
[0108]
The bearing support member 64 includes a cylindrical portion 66 and a flange portion 68 formed at the upper end of the cylindrical portion 66. The cylindrical portion 66 is inserted into the through hole 54 of the optical box 32, and the flange portion 68 is connected to the boss 52. Is in contact with the upper surface of the
[0109]
In the bearing sleeve 24 of the present embodiment, a small-diameter portion 24C having a smaller diameter is formed below the lower end of the small-diameter portion 24B.
[0110]
The small diameter portion 24C of the bearing sleeve 24 is press-fitted into the cylindrical portion 66 of the bearing support member 64, and the lower end surface of the small diameter portion 24B of the bearing sleeve 24 is in contact with the upper surface of the flange portion 68 of the bearing support member 64. .
[0111]
The rotation drive board unit 28 is sandwiched and fixed between the lower end surface of the large diameter portion 24A of the bearing sleeve 24 and the upper surface of the flange portion 68 of the bearing support member 64.
[0112]
On the inner surface of the cylindrical portion 66, a female screw (not shown) is formed at a part on the lower end side. In the present embodiment, the male screw 58 of the bearing fixing member 30 is screwed to this female screw.
[0113]
Therefore, the polygon motor 42 is fixed by pulling the bearing support member 64 downward and pressing the flange portion 68 of the bearing support member 64 against the boss 52 of the optical box 32.
[0114]
In the present embodiment, the heat generated by the polygon motor 42 is transmitted from the bearing sleeve 24 to the metal bearing support member 64 having higher thermal conductivity than the optical box 32 and the bearing fixing member 30, and the bearing fixing member outside the optical box 32. Since a large amount of heat is radiated from the surface, particularly the surface of the radial projection 62, to the outside of the optical box 32, the temperature rise inside the optical box 32 can be extremely reduced.
[0115]
The other operation and effects are the same as those of the first embodiment.
[0116]
In the present embodiment, the male screw 58 of the bearing fixing member 30 is screwed into a female screw (not shown) of the bearing support member 64, so that the bearing fixing member 30 and the bearing support member 64 are fixed. As shown in FIG. 6, the bearing fixing member 30 may be press-fitted into the bearing support member 64 without forming the male screw 58 and the female screw, and the bearing fixing member 30 and the bearing support member 64 are fixed using an adhesive. May be.
[Third Embodiment]
Next, an optical scanning device 10 according to a third embodiment of the present invention will be described with reference to FIG. Note that the optical scanning device 10 of the present embodiment is a modification of the first embodiment, and the same components as those of the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.
[0117]
As shown in FIG. 7, in the optical scanning device 10 of the present embodiment, a heat radiating plate 72 made of a flat metal plate is fixed to the lower end of the cylindrical portion 60 of the bearing fixing member 30 by welding or brazing.
[0118]
In the present embodiment, since the heat radiating plate 72 having a large surface area is fixed to the bearing fixing member 30, the heat radiating effect is improved.
[0119]
Note that a larger number of fins may be provided on the heat sink 72.
[Fourth embodiment]
In the first embodiment, the bearing fixing member 30 is engaged with the large-diameter hole 46 of the bearing sleeve 24. However, the present invention is not limited to this. The bearing sleeve 24, the optical box 32, and the bearing fixing member 30 are integrally formed by projecting from the bottom plate 50 of the optical box 32 as a male screw shape and screwing a nut-shaped bearing fixing member 30 to the male screw portion of the bearing sleeve 24. May be fixed.
[0120]
【The invention's effect】
As described above, since the optical scanning device of the present invention has the above-described configuration, the heat of the polygon motor provided inside the optical box is efficiently radiated to the outside of the optical box without reducing the rigidity of the optical box. This makes it possible to appropriately scan a predetermined position on the image carrier with the light beam and form a high quality image.
[Brief description of the drawings]
FIG. 1A is a sectional view of an optical scanning device according to a first embodiment of the present invention, and FIG. 1B is a bottom view of the optical scanning device showing a bearing fixing member.
FIG. 2 is a plan view of the optical scanning device according to the first embodiment of the present invention.
FIG. 3 is a schematic configuration diagram of an image forming apparatus using the optical scanning device according to the first embodiment of the present invention.
FIG. 4 is a cross-sectional view of an optical scanning device according to a modification of the first embodiment.
FIG. 5 is a sectional view of an optical scanning device according to a second embodiment of the present invention.
FIG. 6 is a cross-sectional view of an optical scanning device according to a modification of the second embodiment.
FIG. 7 is a sectional view of an optical scanning device according to a third embodiment of the present invention.
FIG. 8 is a cross-sectional view of an optical scanning device according to a conventional example.
FIG. 9 is a sectional view of an optical scanning device according to another conventional example.
[Explanation of symbols]
10 Optical scanning device
12. Polygon mirror (rotating polygon mirror)
18 Rotation drive magnet
22 rotating shaft
24 Bearing sleeve (bearing)
26 Stator coil
28 Rotary drive board unit
30 Bearing fixing member
32 optical box
42 polygon motor
46 Large diameter hole (engagement part, concave part, first spiral groove)
54 Through hole
58 Male thread (second spiral groove)
64 Bearing support member
66 cylindrical part (engagement part, first spiral groove)
74 light source

Claims (11)

A light source for emitting a light beam;
A rotating polygon mirror for deflecting and scanning the light beam,
A rotary shaft connected to the rotary polygon mirror, a rotary driving magnet connected to the rotary shaft, a bearing for inserting the rotary shaft from one end in the axial direction and rotatably holding the rotary shaft, and the rotary connected to the bearing; A polygon motor having a rotary drive board unit having a stator coil for rotating the body,
An optical system for imaging the light beam on the surface to be scanned,
An optical box that houses the light source, the polygon motor, and the optical system;
An engaging portion provided at the other axial end of the bearing,
A through-hole provided in the optical box, for inserting a part of the other end of the bearing from the inside of the optical box,
A bearing fixing member for positioning and fixing the polygon motor to the optical box by at least a part disposed outside the optical box and engaging with the engaging portion of the bearing from outside the optical box,
An optical scanning device comprising: The said engaging part of the said bearing is a recessed part, The said bearing and the said bearing fixing member are being fixed by press-fitting a part of the said bearing fixing member in the said recessed part, The claim 1 characterized by the above-mentioned. Optical scanning device. The said engaging part of the said bearing is a recessed part, The said bearing and the said bearing fixing member are being fixed by inserting and adhering a part of the said bearing fixing member in the said recessed part, The Claim 1 characterized by the above-mentioned. An optical scanning device according to claim 1. The engagement portion of the bearing is a hole provided with a first spiral groove on an inner surface, and a second spiral groove is provided on an outer surface of the bearing fixing member,
The optical scanning device according to claim 1, wherein the bearing and the bearing fixing member are fixed by screwing the first spiral groove and the second spiral groove. A light source for emitting a light beam;
A rotating polygon mirror for deflecting and scanning the light beam,
A rotary shaft connected to the rotary polygon mirror, a rotary driving magnet connected to the rotary shaft, a bearing for inserting the rotary shaft from one end in the axial direction and rotatably holding the rotary shaft, and the rotary connected to the bearing; A polygon motor having a rotary drive board unit having a stator coil for rotating the body,
An optical system for imaging the light beam on the surface to be scanned,
An optical box that houses the light source, the polygon motor, and the optical system;
A bearing support member integrally connected to the bearing and having an engagement portion at one end;
A through hole provided in the optical box, for inserting a part of the bearing support member from the inside of the optical box,
A bearing fixing member that positions and fixes the polygon motor to the optical box by being at least partially disposed outside the optical box and engaging with the engaging portion of the bearing support member from outside the optical box. ,
An optical scanning device comprising: The engaging portion of the bearing support member is a concave portion, and the bearing support member and the bearing fixing member are fixed by press-fitting a part of the bearing fixing member into the concave portion. Item 6. The optical scanning device according to item 5. The engaging portion of the bearing support member is a concave portion, and the bearing support member and the bearing fixing member are fixed by inserting and bonding a part of the bearing fixing member to the concave portion. The optical scanning device according to claim 5. The engagement portion of the bearing support member is a hole provided with a first spiral groove on an inner surface, and a second spiral groove is provided on an outer surface of the bearing fixing member,
The optical scanning device according to claim 5, wherein the bearing support member and the bearing fixing member are fixed by screwing the first spiral groove and the second spiral groove. . 9. An elastic member for generating a repulsive force between the bearing fixing member and the optical box is arranged between the bearing fixing member and the optical box. Item 2. The optical scanning device according to item 1. Part or all of the bearing fixing member is made of an elastic material so as to have a repulsive force between the bearing fixing member and the optical box when the bearing fixing member and the bearing are engaged. The optical scanning device according to any one of claims 1 to 9, wherein: The optical scanning according to any one of claims 1 to 10, wherein a part or all of the bearing fixing member is made of a material having a higher thermal conductivity than the optical box. apparatus.

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