JP2005065499A - Motor, light deflector, image forming device, and method for manufacturing motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize the miniaturization of a motor in which the rotating body side is rotated while floating to the fixed shaft receiving side, a light deflector provided with the motor, an image forming device, and a method for manufacturing the motor. <P>SOLUTION: The motor is provided with the rotating body 15, which is provided with a base member 11, a bearing 20 rotated to the base member, a flange 18 fixed to the outer peripheral face of the bearing, and a polygon mirror 17 fixed to the flange with an adhesive. An adhesive layer 16 is provided between the outer peripheral face 20a of the bearing, in which the flange is fixed to the outer peripheral face of the bearing by shrinkage fitting, and the inner peripheral face 18b of the flange. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a motor that rotates while a rotator side floats with respect to a fixed bearing side, an optical deflection apparatus including the motor, an image forming apparatus, and a method for manufacturing the motor.

  2. Description of the Related Art Conventionally, in an electrophotographic image forming apparatus such as a laser beam printer or a digital copying machine, an optical deflection apparatus that performs light beam scanning is used to write an image on a photosensitive drum. Such an optical deflecting device is provided with a dynamic pressure bearing in which a polygon mirror fixed with a magnet is rotatably configured via a bearing, and a motor configured by providing a coil on a substrate facing the magnet of the dynamic pressure bearing. It has. An example of such a known motor is shown in FIG.

  5 includes a base plate 110, a rotating body 150 having a polygon mirror 170 on which a mirror surface 171 is formed, a pressing plate 160 for the polygon mirror 170, and a flange 180 for fixing the polygon mirror 170, and a flange 180. The bearing 200 is provided on the inner peripheral surface 181 and the magnet 220 is fixed to the concave portion of the flange 180. In this motor, a lower thrust bearing 211 is fixed to the lower portion of the central shaft 110 of the base plate 110, and a bearing 190 is fixed through the central shaft 111. Further, an upper thrust bearing 210 is fixed to the upper portion of the central shaft 111. The plate 250 is fixed by screwing, and a recess 260 fixed to the central shaft 111 of the base plate 110 is formed by the bearing 190 and the upper and lower thrust bearings 210 and 211. The motor includes a coil 130 fixed on the printed circuit board 120 of the base plate 110 so as to face the magnet 220. The motor 200 rotates at high speed while forming an air gap between the bearing 200 and the recess 260 together with the rotating body 150 by the interaction with the magnet 220 when the coil 130 is energized.

  The motor as described above is required to be further downsized due to a demand for space saving for downsizing the apparatus. However, with the miniaturization of the motor, the following problems arise.

  (1) When the above-mentioned bearing 200 is fixed to the inner peripheral surface 181 of the flange 180, conventionally, shrink fitting has been used. When the motor is further downsized, the bearing 200 is also downsized, and when the shrink fit is increased, the distortion of the bearing becomes a problem.

  (2) In order to adjust the dynamic balance of the rotating body 150, conventionally, the depression 160a is partially provided in the holding plate 160 of the polygon mirror 170, but the holding plate is omitted to reduce the size of the motor. If the concave portion for adjusting the dynamic balance is formed directly on 170, the flatness of the polygon mirror is affected. Further, when the pressing plate is omitted and the polygon mirror 170 is fixed to the flange 180, it is necessary to eliminate as much as possible the influence of deformation or the like on the polygon mirror from the flange side.

  In view of the problems of the prior art as described above, the present invention solves the problems in realizing downsizing in a motor that rotates while the rotating body side floats with respect to the fixed bearing side, and the motor that has been downsized, It is an object of the present invention to provide an optical deflection apparatus, an image forming apparatus, and a method of manufacturing the motor.

This object is achieved by the following means. That is, the invention according to claim 1 comprises: “a rotating member including a base member, a bearing rotating with respect to the base member, and a flange fixed to the outer peripheral surface of the bearing by shrink fitting, A motor characterized in that an adhesive layer is provided between the outer peripheral surface of the bearing and the inner peripheral surface of the flange.

The invention according to claim 2 is: "The rotating body includes a polygon mirror fixed to the flange by an adhesive and a magnet fixed to a surface of the flange opposite to the fixing surface of the polygon mirror. ,
Providing a convex portion on the end face of the polygon mirror, partially removing the convex portion for balance adjustment,
The motor according to claim 1, wherein an outer diameter of an adhesive surface between the polygon mirror and the flange is equal to or smaller than an inner diameter of the magnet. It is.

  According to a third aspect of the invention, the motor according to the second aspect, wherein the depth of the concave portion formed by partially removing the convex portion is equal to or less than the height of the convex portion. . "

  The invention according to claim 4 is an “optical deflecting device in which the motor according to any one of claims 1 to 3 includes a polygon mirror that rotates together with the rotating body”.

  The invention according to claim 5 is an “image forming apparatus comprising the light deflecting device according to claim 4, wherein image information is written on a photosensitive member by light reflected by the polygon mirror”. .

  The invention according to claim 6 is a method for producing a motor comprising: a base member, a bearing that rotates relative to the base member, and a rotating body that is fixed to an outer peripheral surface of the bearing. The step of applying an adhesive to the outer peripheral surface of the bearing, the step of heating the flange, the step of inserting the bearing into the inner peripheral surface of the heated flange, and the bearing being inserted. And a step of cooling the flange. ”.

  According to the first aspect of the present invention, when the bearing is downsized with the miniaturization of the motor, it is easy to be distorted by the influence of shrink fitting with the flange. However, by providing the adhesive layer, the shrink fitting is strengthened. Even if it is not excessive, sufficient strength can be obtained, and the bearing can be fixed to the flange with sufficient strength without distortion due to shrink fitting. Therefore, it is possible to reduce the size of the motor and to obtain a highly reliable motor. The present invention can be applied to the fixing of the bearing and the flange even when the motor is not particularly downsized, and the bearing can be fixed to the flange with sufficient strength without being distorted by shrink fitting.

  According to the second aspect of the present invention, since the flange and the polygon mirror are fixed by the adhesive, a conventional pressing member for fixing the polygon mirror to the flange can be omitted, which contributes to miniaturization of the motor. it can. Even when the flange is deformed due to a temperature change at the bonded portion of the lower end surface of the flange 18 to which the magnet is bonded, the outer diameter of the bonded surface between the flange and the polygon mirror 17 is set to be larger than the inner diameter of the end portion of the magnet. By making it small, it is possible to prevent the deformation of the flange from being transmitted to the polygon mirror. For this reason, the deformation | transformation resulting from the temperature change of a polygon mirror can be prevented, and the flatness of a mirror surface is not affected.

  According to the third aspect of the present invention, the convex portion protruding from the upper end surface of the polygon mirror is shaved to adjust the balance of the rotating body 15, so that the polygon mirror is less likely to be distorted due to the shaving. Deterioration of the flatness of the surface can be prevented. Further, since the depth of the concave portion formed by partially removing the convex portion is equal to or less than the height of the convex portion, the polygon mirror is hardly distorted, which is preferable in terms of preventing the flatness of the mirror surface from being deteriorated.

  According to the fourth aspect of the present invention, the optical deflection apparatus can be provided with the polygon mirror in which the above-mentioned motor rotates together with the rotating body, and can contribute to the miniaturization of the optical deflection apparatus.

  According to a fifth aspect of the present invention, an image forming apparatus includes the above-described light deflecting device, and can write image information on a photosensitive member by light reflected by the polygon mirror, thereby reducing the size of the image forming apparatus. Can contribute.

  According to the sixth aspect of the present invention, the bearing can be fixed to the flange with sufficient strength without being distorted by shrink fitting.

  Hereinafter, first to third embodiments of the present invention will be described with reference to the drawings.

<First Embodiment>
FIG. 1 is a side sectional view of an optical deflecting device showing a first embodiment of the present invention. 1 includes a base member 11 made of a metal such as aluminum, a printed circuit board 12 attached and fixed to the base member 11, and a coil 13 formed and fixed on the printed circuit board 12. And a fixed yoke 14 provided on the base member 11 so as to face the coil 13, and a rotating body 15 that rotates with respect to the base member 11.

  The rotating body 15 includes a polygon mirror 17 having a mirror surface 17a formed thereon, a flange 18 having the polygon mirror 17 fixed to an upper end surface 18c thereof by an adhesive, and a bearing 20 fixed to an inner peripheral surface 18b of the flange 18. And a magnet 22 fitted and fixed in the concave portion 18a of the flange 18 so as to face the IL 13 with the printed circuit board 22 interposed therebetween, and each portion rotates integrally. The diameter of the polygon mirror 17 is smaller than that of the conventional one in FIG. 5, so that the bearing 20 is smaller than the conventional one and has a smaller diameter.

  In addition, the lower thrust bearing 21b is fitted in the lower portion of the central shaft 11a of the base member 11, and then the radial bearing 19 is fitted through the central shaft 11a. Further, the upper thrust bearing 21a is placed on the upper portion of the central shaft 11a. Are fitted and fixed with screws 25 thereon. Thus, the upper thrust bearing 21a, the radial bearing 19 and the lower thrust bearing 21b are fixed to the base member 11, and the recess 26 is formed by the upper thrust bearing 21a, the lower thrust bearing 21b and the bearing 19. ing. The upper and lower thrust bearings 21a and 21b and the radial bearing 19 are made of ceramics.

  The base member 11, the upper thrust bearing 21 a, the radial bearing 19, the lower thrust bearing 21 b, the rotating body 15, the coil 13, and the fixed yoke 14 constitute a motor. The bearing 20 fixed to the flange 18 is located in the recess 26 through a gap, and the rotating body 15 rotates together with the bearing 20 by the interaction with the magnet 22 when the coil 13 is energized. Rotating at a high speed while forming an air gap between them.

  Next, a method for manufacturing the above-described rotating body 15 will be described. First, an adhesive is applied to the outer peripheral surface 20 a of the bearing 20. The flange 18 is cooled after the bearing 20 having the outer peripheral surface 20a coated with an adhesive is inserted into the heated inner peripheral surface 18b of the flange 18. Thereby, the bearing 20 is fixed to the inner peripheral surface 18b of the flange 18 by shrink fitting, and the adhesive layer 16 is formed at a contact portion (shrink fitting fixing portion) between the inner peripheral surface 18b and the outer peripheral surface 20a of the bearing 20. To do. Next, the polygon mirror 17 is fixed to the upper end surface 18c of the flange 18 with an adhesive, and the magnet 22 is fixed to the recess 18a with an adhesive. As the adhesive, an acrylic anaerobic adhesive is preferable, but other adhesives may be used as long as they do not deteriorate at the shrink-fit temperature and melt at the shrink-fit temperature to be cured.

  As described above, when the bearing 20 is downsized and the diameter thereof is reduced, the bearing 20 is easily distorted due to the effect of shrink fitting with the flange 18. However, in the above optical deflecting device 10, the inner peripheral surface 18 b of the flange 18 and the bearing. By providing the adhesive layer 16 at a portion where the shrink fit is fixed to the outer peripheral surface 20a, a sufficient strength can be obtained without strengthening the shrink fit so that the bearing 20 is distorted. It can be fixed to the flange with sufficient strength without distortion by shrink fitting. Therefore, miniaturization of the motor can be realized without impairing reliability.

  The effects of the present embodiment will be further described with reference to examples. In the example, Loctite 648UV was used as an adhesive, and the bearing and the flange were fixed by shrink fitting and adhesive. The shrink-fit temperature was 170-200 ° C. Further, in the comparative example, the bearing and the flange were fixed by shrink fitting under the same conditions as in the example except that no adhesive was used. Next, the heat shock test was performed about the Example and the comparative example by repeating a heat shock in the temperature range of -30 degreeC-75 degreeC for 1 hour each.

  With respect to the example and the comparative example, the change in the step distance between the upper end surface 20b of the bearing 20 and the upper end surface 18c of the flange 18 is measured as the amount of deviation (μm) between the bearing and the flange for each number of heat shocks. did. The measurement results are shown in FIG. From FIG. 2, it can be seen that in the embodiment using the shrink fit and the adhesive in combination, the displacement between the bearing and the flange due to the heat shock can be considerably reduced as compared with the comparative example having only the shrink fit. Thus, it turns out that a bearing and a flange can be fixed with sufficient intensity | strength by using shrink fitting and an adhesive agent together. If the amount of deviation between the bearing and the flange becomes large, the vibration of the rotating body increases due to the balance change, the tilt angle of the mirror surface 17a of the polygon mirror 17 increases, and the characteristics of the optical deflecting device are deteriorated. However, according to the optical deflecting device according to the present embodiment, such a deviation amount can be greatly reduced, so that there is no problem of characteristic deterioration.

  In addition to Loctite 648UV, for example Loctite 525UV, Loctite 510, and ThreeBond 1375B can be used as the acrylic anaerobic adhesive, but Loctite 648UV is particularly good in terms of characteristics and mass productivity.

<Second Embodiment>
FIG. 3 is a side sectional view of a fourth optical deflection apparatus showing a second embodiment of the present invention. The second optical deflecting device 50 shown in FIG. 3 has the features of FIG. That is, as shown in FIG. 1, by using a shrink fit and an adhesive together, the bearing 20 and the flange 18 can be fixed with sufficient strength while suppressing the distortion caused by the shrink fit. Such a pressing member is omitted, and the convex portion 17d protruding from the upper end surface 17c of the polygon mirror 17 is cut to form a concave portion 17e for adjusting the balance of the rotating body 15, and the polygon mirror 17 is affected by the shaving. The occurrence of distortion is prevented, the flange 18 and the polygon mirror 17 are fixed with an adhesive, and the outer diameter D of the bonding surface 41 between the flange 18 and the polygon mirror 17 is made larger than the inner diameter d of the end portion 22a of the magnet 22. The deformation of the flange 18 due to the temperature change is prevented from being transmitted to the polygon mirror 17, and the deformation due to the temperature change of the polygon mirror 17 and the mirror surface 17a is prevented. It is obtained so as to stop.

  As shown in FIG. 3, in the second light deflecting device 50, the polygon mirror 17 is fixed to the upper end surface 18c of the flange 18 with an adhesive at the lower side surface 17b, and the upper end surface is circumferentially attached to the upper end surface 17c. A projecting portion 17d protruding from 17c is provided. The convex portion 17d is partially cut for balance adjustment of the rotating body 15, and a concave portion 17e is formed as a cut portion. Although the position of the recess 17e on the circumference varies depending on the individual rotating bodies, the depth of the recess 17e is smaller than the height of the protrusion 17d and does not reach the level of the upper end surface 17c.

  According to the light deflecting device 50 as described above, the convex portion 17d protruding from the upper end surface 17c of the polygon mirror 17 is shaved for balance adjustment of the rotating body 15, so that distortion occurs in the polygon mirror 17 due to the shaving effect. It becomes difficult to prevent the deterioration of the flatness of the mirror surface 17a. Therefore, the pressing member that has been partially cut for adjusting the balance of the rotating body as shown in FIG. 5 can be omitted, which contributes to miniaturization of the motor. Further, since the depth of the concave portion 17e formed by partially removing the convex portion 17d is equal to or less than the height of the convex portion 17d, the polygon mirror 17 is difficult to be distorted and the flatness of the mirror surface 17a is prevented from being deteriorated. This is preferable.

  According to the second light deflecting device 50, the flange 18 and the polygon mirror 17 are fixed by an adhesive, so that the conventional pressing member for fixing the polygon mirror to the flange as shown in FIG. 5 can be omitted. Can contribute to downsizing. Even when the flange 18 is deformed due to a temperature change at the bonded portion of the lower end surface 18d of the flange 18 to which the magnet 22 is bonded, the outer diameter D of the bonding surface 41 between the flange 18 and the polygon mirror 17 is set to the magnet 22. By making it smaller than the inner diameter d of the end portion 22a, it is possible to prevent the deformation of the flange 18 from being transmitted to the polygon mirror 17. For this reason, the deformation | transformation resulting from the temperature change of the polygon mirror 17 can be prevented, and the flatness of the mirror surface 17a is not affected.

  According to the second optical deflecting device 50 of FIG. 3, a pressing member for fixing the mirror is unnecessary, the bearing 20 can be reduced in diameter, and downsizing can be achieved. Further, it is possible to prevent the mirror surface 17a from being deformed due to the shaving for adjusting the balance of the rotating body 15 and the distortion in the adhesive surface 41 between the magnet 22 and the flange 18 due to temperature change. Further, the deformation of the bearing 20 due to the fixing with the flange 18 is small, and a highly reliable optical deflecting device having a sufficient fixing strength with the flange can be realized even if the bearing 20 has a small diameter.

<Third Embodiment>
Next, as a third embodiment, an example in which the optical deflecting device shown in FIGS. 1 and 3 is incorporated in an optical scanning optical unit of an image forming apparatus will be described with reference to FIG. FIG. 4 is a perspective view showing a schematic structure of the optical scanning optical unit.

  As shown in FIG. 4, the optical scanning optical unit includes an optical deflecting device 72 fixed on a base 100 and having a polygon mirror 73, a semiconductor laser 76, a collimator lens (beam shaping optical system) 75, and a first cylindrical lens. 71, an fθ lens 70, a second cylindrical lens 80, a reflection mirror 90, a timing detection mirror 82, and a synchronization detector 81. The beam emitted from the semiconductor laser 76 is converted into parallel light by the collimator lens 75, and enters the polygon mirror 73 rotating in the direction of the arrow through the first cylindrical lens 71 of the first imaging optical system. Reflected light from the mirror surface 73 a of the polygon mirror 73 passes through the second imaging optical system including the fθ lens 70 and the second cylindrical lens 80, and passes through the periphery of the photosensitive drum 91 of the image forming apparatus via the reflecting mirror 90. Scanning is performed in the main scanning direction with a predetermined spot diameter on the surface. Synchronous detection for each line in the main scanning direction is performed by causing a light beam before the start of scanning to enter the synchronous detector 81 via the mirror 82, and the photosensitive drum 101 rotates in the sub-scanning direction in synchronization therewith. .

  As described above, the image information can be written on the photosensitive drum 101 by the laser light from the semiconductor laser 76. In this case, the optical deflection device 72 is miniaturized as described above. In addition to contributing to downsizing of the image forming apparatus, the flatness of the mirror surface 73a can be maintained and deterioration of the characteristics of the optical deflection apparatus can be prevented.

  As described above, the present invention has been described with reference to the embodiments. However, the present invention is not limited to these embodiments, and various modifications can be made within the scope of the technical idea of the present invention. For example, the motor according to the present invention may be applied to devices other than the optical deflection device. 3 may be provided on the upper end face 18c side of the flange 18 or may be provided on both. Further, the optical deflection device may be applied to other devices such as a barcode other than the image forming device.

  As described above, according to the present invention, in a motor that rotates while the rotor side floats with respect to the fixed bearing side, distortion of a small-diameter bearing is prevented while obtaining sufficient fixing strength, and the conventional pressing member is adversely affected. It can be omitted while suppressing the problem, and the problems in realizing miniaturization of the motor can be solved. As a result, a highly reliable and miniaturized motor, an optical deflection apparatus including the motor, an image forming apparatus, and a method of manufacturing the motor can be provided.

It is a sectional side view of the optical deflection apparatus by a 1st embodiment of the present invention. It is a figure which shows the change of the deviation | shift amount of a bearing and a flange in the heat shock test implemented about the Example and comparative example of the optical deflection | deviation apparatus of FIG. It is a sectional side view of the optical deflection apparatus by the 2nd Embodiment of this invention. It is a perspective view of the optical scanning optical unit of the image forming apparatus by the 3rd Embodiment of this invention. It is side sectional drawing of the conventional optical deflection | deviation apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Base member 11a Central axis 12 Printed circuit board 13 Coil 14 Fixed yoke 15 Rotor 16 Adhesive layer between the bearing 20 and the flange 18 Polygon mirror 17a Mirror surface 17b Upper side surface 17c Lower side surface 17d Convex part 17e Concave part 17f Protrusion part 18 Flange 18a Recessed part 18b Inner peripheral surface 18c Upper end surface 18d Lower end surface 19 Radial bearing 20 Rotating body side bearing 20a Outer surface of bearing 20a Upper thrust bearing 21b Lower thrust bearing 22 Magnet 22a End portion on inner side of magnet 22 41 Adhesive surface 72 Optical deflection device 91 Photosensitive drum d Inner diameter of magnet 22 on inner diameter side D Outer diameter of bonding surface 41

Claims (6)

A rotating member including a base member, a bearing that rotates with respect to the base member, and a flange that is fixed to the outer peripheral surface of the bearing by shrink fitting, the outer peripheral surface of the bearing and the inner periphery of the flange A motor characterized in that an adhesive layer is provided between the surface and the surface. The rotating body includes a polygon mirror fixed to the flange by an adhesive, and a magnet fixed to a surface of the flange opposite to a fixing surface of the polygon mirror,
Providing a convex portion on the end face of the polygon mirror, partially removing the convex portion for balance adjustment,
The motor according to claim 1, wherein an outer diameter of an adhesive surface between the polygon mirror and the flange is equal to or smaller than an inner diameter of the magnet. The motor according to claim 2, wherein a depth of a concave portion formed by partially removing the convex portion is equal to or less than a height of the convex portion. An optical deflecting device, wherein the motor according to claim 1 includes a polygon mirror that rotates together with the rotating body. An image forming apparatus comprising the light deflecting device according to claim 4, wherein image information is written on a photosensitive member by light reflected by the polygon mirror. A method of manufacturing a motor comprising: a base member; a bearing that rotates with respect to the base member; and a rotating body that is fixed to the outer peripheral surface of the bearing, and is bonded to the outer peripheral surface of the bearing Applying the agent, heating the flange, inserting the bearing into the inner surface of the heated flange, and cooling the flange into which the bearing is inserted. A manufacturing method of a motor characterized by the above.

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