JP2008304628A - Optical deflector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical deflector in which plane tilt is accurately adjustable by a simple configuration that an elastic member is provided on the lower face of a polygon mirror and the upper face of the polygon mirror is pressurized by adjustment screws. <P>SOLUTION: The optical deflector comprises: a sleeve turnably mounted at the outside of a fixed shaft; a flange fixed on the sleeve; an elastic member mounted on the flange; a polygon mirror mounted on the elastic member; a pressurizing member which is fixed on the sleeve at a part above the polygon mirror and has a plurality of adjustment screws, wherein the tip of the adjustment screws are abutted to the upper face of the polygon mirror to pressurize the polygon mirror against the flange side, wherein the number of the adjustment screws is three or more, the result of the number of mirror faces of the polygon mirror divided by the number of the adjustment screws becomes an integer, the adjustment screws are provided on the pressurizing member with a constant pitch, thus the plane tilt of the polygon mirror is adjustable by the adjustment screws. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an optical deflector used in an image forming apparatus such as a laser printer or a digital copying machine.

  Conventionally, as an optical deflector used in an image forming apparatus such as a laser printer or a digital copying machine, one shown in FIG. 19 is known (for example, see Patent Document 1).

The optical deflector includes a columnar fixed shaft 101 fixedly disposed on the housing 100 and a rotating body 110 that is rotatably supported by the fixed shaft 101.
The rotating body 110 includes a sleeve 111 disposed with a slight gap between the rotating shaft 110, a ring-shaped magnet 112 fixedly disposed on the upper inner side of the sleeve 111, and an outer central portion of the sleeve 111. A polygon mirror 113 fixedly disposed on the lower surface of the sleeve 111 and a ring-shaped drive magnet 115 fixedly disposed on the outer bottom of the sleeve 111 via a flange 114.
Reference numeral 116 denotes a groove in which a balance weight (not shown) for correcting the eccentricity of the weight of the rotating body 110 is attached.

  A ring-shaped magnet 102 is fixedly disposed on the outer side of the upper portion of the fixed shaft 101 so as to face a ring-shaped magnet 112 provided on the rotating body 110. The rotating body 110 is supported by the ring-shaped magnets 102 and 112. A thrust magnetic bearing S for bearing in the thrust direction is configured.

  Furthermore, an iron core coil 103 is fixedly disposed in the housing 100 so as to face a ring-shaped driving magnet 115 provided on the rotating body 110, and the rotating body 110 is rotated by the driving magnet 115 and the iron core coil 103. The motor M to be configured is configured.

  Of the sleeve 111 of the rotating body 110, the inner peripheral surface 111a facing the fixed shaft 101 is finished with a bearing surface, while the outer peripheral surface 101a of the fixed shaft 101 facing the inner peripheral surface 111a of the sleeve 111. Are formed with herringbone-shaped grooves 104 as shown by broken lines in the figure, and the rotating body 110 is radially formed by the grooves 104 provided on the inner peripheral surface 111a of the sleeve 111 and the outer peripheral surface 101a of the fixed shaft 101. A radial dynamic pressure bearing R that is supported in the direction is configured.

In this optical deflector, when the rotating body 110 is rotated by the motor M, the rotating body 110 is supported in a non-contact manner with a fixed distance (gap) with respect to the fixed shaft 101 by the radial dynamic pressure bearing R, and the thrust magnetism. The bearing S supports the fixed shaft 101 at a constant height. Accordingly, there is an advantage that the height of the optical deflector can be made lower than that of a type using a dynamic pressure bearing as a bearing in the thrust direction.
In addition, since the position of the center of gravity of the rotating body 110 can be set to a substantially central position of the rotating body 110, the rotating body 110 can be stably rotated.

  In general, this optical deflector has a variation with respect to a certain reference surface of each mirror surface when the beam is scanned onto the photosensitive member or the like by reflection of each reflection surface of the polygon mirror, which is a surface tilt. In order to improve the image quality of image formation, it is necessary to adjust the surface tilt of the polygon mirror with high accuracy to eliminate it.

  In order to perform this surface tilt adjustment, a light beam scanning device has been proposed in which a mounting seat is provided on the lower surface of the polygon mirror, a rigid plate is provided on the upper surface, and a surface tilt adjusting mechanism is provided to press the rigid plate with an adjusting screw. (For example, refer to Patent Document 2).

  Since this light beam scanning device is made of only a rigid material, the surface tilt of the polygon mirror is adjusted by plastically deforming the rigid plate by pressurizing the rigid plate with an adjusting screw.

JP-A-5-71532 Japanese Patent Laid-Open No. 62-164984

  However, when the rigid plate is plastically deformed with the adjusting screw, the polygon mirror mainly composed of aluminum is plastically deformed. For this reason, there exists a problem that the flatness of the mirror surface of a polygon mirror worsens.

  In addition, the adjustment of the tilting with a plurality of adjustment screws requires reversible fine adjustment of each adjustment screw (fine adjustment by rotating the adjustment screw left and right) as the adjustment of the tilting accuracy becomes higher. When the rigid plate is plastically deformed, there is a problem that reversible fine adjustment cannot be performed.

  The present invention has been made to solve such a problem, and an elastic member is provided on the lower surface of the polygon mirror, and the upper surface of the polygon mirror is pressed with an adjusting screw, so that the surface tilt adjustment can be performed with high accuracy. An object of the present invention is to provide an optical deflector that can be used.

  The present invention provides a sleeve rotatably attached to the outside of a fixed shaft, a flange fixed to the sleeve, an elastic member placed on the flange, and placed on the elastic member. A polygon mirror having a plurality of mirror surfaces, and a pressing member fixed to the sleeve at the upper part of the polygon mirror and having a plurality of adjustment screws attached in parallel to the fixed axis, and the tip of the adjustment screw on the upper surface of the polygon mirror The present invention relates to an optical deflector in which a polygon mirror is pressed against the flange side.

  The number of adjusting screws is three or more, and is an integer that is an integer when the number of mirror surfaces of the polygon mirror is divided by the number of adjusting screws. The adjusting screws are attached to the pressing member at equal intervals. It has been.

  That is, the number M of adjustment screws (M ≧ 3) is M when N ÷ M = integer, where N is the number of polygon mirror surfaces. For example, when the number of faces of the polygon mirror N = 6, if M = 3, N ÷ M = 2 (integer), so the number of adjusting screws can be three. Even if M = 6, N ÷ M = 1 (integer), so the number of adjusting screws can be six. However, when the number of polygon mirror surfaces is N = 6, if M = 4, N ÷ M = 1.5, which is not an integer, so the number of adjustment screws cannot be four.

  In the present invention, in addition to the above-mentioned number, it is necessary that each adjusting screw is attached to the pressing member at equal intervals. In other words, when the number of the adjusting screws is three, the adjusting screws need to be 120 ° apart, and when the number is six, the adjusting screws need to be 60 ° apart. When expressed by a general formula, when the number of adjusting screws is M (M ≧ 3), the interval between the adjusting screws is 360 ° / M.

  Even after the optical deflector is assembled, the optical deflector having such a configuration can be adjusted with high accuracy by adjusting the adjustment screw finely. Here, the surface tilt refers to the tilt error of the reflecting surface caused by the assembly accuracy and processing accuracy of the polygon mirror. If this surface tilt is large, the position at which the beam reflected by the reflecting surface of the polygon mirror forms an image on the image forming surface of the photosensitive member changes, which greatly affects the image quality.

  Further, the present invention can be applied not only to the above-described optical deflector in which the sleeve rotates but also to an optical deflector in which the rotation shaft rotates. That is, a rotating shaft rotatably attached to the inside of the bearing, a flange fixed to the rotating shaft, an elastic member placed on the flange, and placed on the elastic member, A polygon mirror having a mirror surface and a pressing member fixed to a rotating shaft or a flange at the upper part of the polygon mirror and having a plurality of adjustment screws attached in parallel to the fixed axis. The present invention can also be applied to an optical deflector in which a polygon mirror is pressed against the flange side in contact with the upper surface.

  Also in this type of optical deflector, as described above, the number of adjustment screws is three or more, and is an integer that is an integer when the number of mirror surfaces of the polygon mirror is divided by the number of adjustment screws. The adjustment screws must be attached to the pressing member at equal intervals.

  Even in the optical deflector having such a configuration, as described above, after the optical deflector is assembled, fine adjustment of the adjustment screw can be performed to adjust the surface tilt with high accuracy.

  In the two types of optical deflectors described above, it is desirable to provide rigid plates on the upper and lower surfaces of the polygon mirror. The reason why the rigid plate is provided on the upper surface of the polygon mirror is to prevent or disperse the deformation of the polygon mirror at the contact point because three or more adjustment screws are in contact with the upper surface of the polygon mirror.

  The reason why the rigid plate is provided on the lower surface of the polygon mirror is to prevent or disperse the deformation of the polygon mirror at the contact point between the polygon mirror and the elastic member because there is an elastic member on the lower surface of the polygon mirror.

  In this way, by providing rigid plates on the upper and lower surfaces of the polygon mirror, it is possible to prevent or disperse the deformation of the polygon mirror at the contact point between the adjusting screw and the elastic member and the polygon mirror. Therefore, the adjustment screw and fine adjustment of the adjustment screw while preventing or minimizing the deformation of the mirror surface of the polygon mirror (deterioration of the flatness of the mirror surface) caused by the deformation of the polygon mirror that occurs at the contact point between the elastic member and the polygon mirror Can be adjusted with high accuracy.

  In the optical deflector according to the present invention, a protrusion may be formed at the center of the lower surface of the pressing member, and the protrusion may be placed on a polygon mirror or a rigid plate.

  With this configuration, the adjustment screw that does not require adjustment can maintain an appropriate distance from the upper surface of the polygon mirror or the upper surface of the rigid plate. In other words, when there are three adjustment screws on a polygon mirror with six mirror surfaces, assuming that the face tilt adjustment is performed using one of the adjustment screws, the tip of the other two adjustment screws Is preferably separated from the polygon mirror or rigid plate. This is because if the other two adjusting screws hit the polygon mirror or the rigid plate for some reason, surface tilt occurs.

  Therefore, a protrusion is formed at the center of the lower surface of the pressing member, and this protrusion is placed on a polygon mirror or rigid plate, so that it can be used to adjust the surface tilt by the height of the protrusion (the amount of protrusion in the axial direction). The tip of the adjustment screw which has not been made can be separated from the upper surface of the polygon mirror or the rigid plate.

  According to the present invention, in the above-described optical deflector, the position of the adjustment screw may be on each line connecting each ridge line portion between each mirror surface of the polygon mirror and the center of the polygon mirror. Here, the ridge line portion refers to a boundary portion between mirror surfaces formed on the outer periphery of the polygon mirror.

  For example, in the case of a polygon mirror having six mirror surfaces, there are six ridge lines, so there are six lines connecting each ridge line and the center of the polygon mirror at 60 ° intervals. When there are six adjustment screws, the tips of all the adjustment screws are positioned on the six lines described above. When there are three adjustment screws, the three adjustment screws are positioned on three lines at intervals of 120 ° out of the six adjustment screws.

  With such a configuration, the deformation of the polygon mirror caused by the tip of the adjustment screw coming into contact with the polygon mirror is inside the ridge line portion (far from the mirror surface), so that the influence on the flatness of the mirror surface can be reduced.

  In the optical deflector according to the present invention, the adjustment screw may be positioned inside the center of the mirror surface of the polygon mirror. Here, the center inner side of the mirror surface means a position on the polygon mirror side and equidistant from the ridge line portions existing at both ends of one mirror surface.

  With such a configuration, since the inside of the mirror surface is directly pressed with the adjusting screw, the surface tilt adjustment can be performed directly, so that the time required for adjusting the surface tilt can be shortened.

  In the present invention, the adjusting screw may be locked in the above-described optical deflector. Here, the locking process is a process performed on the screw portion of the adjustment screw that has a high locking effect against vibration and impact and can be used several times.

  By using an adjustment screw that has been locked to the screw part, the screw part of the adjustment screw is free from rattling, so the adjustment screw can be rotated in small units, and the tilting adjustment can be performed with higher accuracy. be able to.

  Further, according to the present invention, a spot facing may be provided at a position where the adjustment screw in the pressing member is attached, and the head of the adjustment screw may be buried in the spot facing.

With this configuration, the head of the adjustment screw does not protrude from the upper surface of the pressing member, so that windage loss can be reduced. This is because if the head of the adjusting screw protrudes from the upper surface of the pressing member, air resistance is generated, which becomes a negative factor for the rotation of the rotating body.

  Here, the windage loss refers to energy loss caused by the resistance of the rotating rotating body to the surrounding gas (usually air). This windage loss increases as the rotational speed of the rotating body increases.

  In the present invention, it is desirable that the point where the adjusting screw is in contact with the polygon mirror or the upper rigid plate is positioned directly above the point where the elastic member is in contact with the polygon mirror or the lower rigid plate.

  In this case, the force points applied to the polygon mirror are substantially the same in the vertical direction, so that the surface tilt adjustment can be made with high accuracy.

  According to the present invention, it is possible to provide an optical deflector capable of highly accurate surface tilt adjustment even after the optical deflector is assembled.

  Hereinafter, the present invention will be described in detail using examples.

A first embodiment according to the present invention will be described with reference to FIGS.
FIG. 1 is a side sectional view of the optical deflector, and FIG. 2 is a plan view of a rotating body of the optical deflector in FIG. For the sake of easy understanding, the fixed shaft is not shown in cross section in FIG.

  The optical deflector 1 includes a cylindrical fixed shaft 3 fixed to a housing 2 with screws or the like (not shown), and a rotating body 4 that is rotatably supported by the fixed shaft 3.

  The rotating body 4 is placed on a cylindrical sleeve 5 inserted with a slight gap between the rotating shaft 4, a flange 8 fixed at the lower portion of the sleeve 5, and a convex portion 18 of the flange 8. An elastic member 9 such as a ring-shaped leaf spring, a ring-shaped lower rigid plate 19 placed on the elastic member 9, and a plurality of mirror surfaces 20 on the outer peripheral surface are placed on the lower rigid plate 19. The formed polygon mirror 7, the upper rigid plate 11 placed on the polygon mirror 7, the pressing member 6 forcibly inserted into the sleeve 5 by press-fitting or shrink fitting at the upper part of the sleeve 5, and the flange 8 And a drive magnet 12 fixed with an adhesive or the like.

  And since the thrust magnetic bearing is comprised by the magnetic attraction force between this drive magnet 12 and the coil 16 arrange | positioned so that it may be surrounded, the rotary body 4 is always kept in the state where it floated. Yes.

  The drive magnet 12 has a ring-shaped groove 15, and a balance weight made of an adhesive for correcting the eccentricity of the rotating body 4 can be attached to the groove 15.

  A gap is provided between the inner peripheral surface of the polygon mirror 7 and the outer peripheral surface of the sleeve 5. This gap is set such that the inner peripheral surface of the polygon mirror 7 does not hit the outer peripheral surface of the sleeve 5 even if the polygon mirror 7 is adjusted to be inclined. In this embodiment, a gap of 5 microns is provided.

  The ring-shaped pressing member 6 is provided with six screw holes at an interval of approximately 60 degrees, and an adjustment screw 14 is attached to each of the screw holes. The tip of the adjustment screw 14 is in contact with the upper surface of the upper rigid plate 11.

  As shown in FIG. 2, the adjustment screw 14 is positioned on a line connecting the ridge line portions 10 between the mirror surfaces 20 and the center of the polygon mirror 7. For this reason, the point at which the adjustment screw 14 presses the polygon mirror 7 is away from the mirror surface 20, so that the deformation of the mirror surface 20 of the polygon mirror 7 due to the pressing force by the adjustment screw 14 can be minimized.

  By rotating at least one of these six adjusting screws 14 in either the left or right direction, the entire polygon mirror 7 is tilted in the direction A in FIG. ) Can be fine-tuned.

  At this time, since the elastic member 9 is under the lower rigid plate 19 attached to the lower surface of the polygon mirror 7, when the adjustment screw 14 is rotated to the right and the tip of the adjustment screw protrudes downward, the elastic member 9 The amount of deformation increases. That is, the elastic member 9 is deformed in a direction to be crushed. Further, when the adjustment screw 14 is rotated counterclockwise and the tip of the adjustment screw is retracted upward, the deformation amount of the elastic member 9 is reduced. That is, the elastic member 9 is deformed in the direction in which it returns.

  As described above, when the adjustment screw 14 is rotated right or left and the tip of the adjustment screw 14 is moved downward or upward, the elastic member 9 is deformed according to the amount of movement of the tip of the adjustment screw 14. The mirror 7 itself is not deformed, and the flatness of the mirror surface 20 of the polygon mirror 7 is not affected (deteriorated) by the adjustment work of the surface tilt.

  Further, since the elastic member 9 is used to press the polygon mirror 7 against the adjustment screw 14 in order to follow the movement of the tip of the adjustment screw 14, the elastic member 9 has been subjected to corrosion treatment. For example, there is no deterioration, and the elastic member 9 is not deformed by the centrifugal force generated by the high-speed rotation of the rotating body 4.

  The upper rigid plate 11 and the lower rigid plate 19 attached to the upper and lower surfaces of the polygon mirror 7 are for receiving the force of the adjusting screw 14 received by the polygon mirror 7 and the force of the spring member 9. 7 to prevent the deformation of 7.

  In the present embodiment, the thread portion of the adjustment screw 14 may be locked. In this case, since the nylon resin is welded to the screw portion of the adjustment screw, the adjustment screw 14 does not rattle. For this reason, the surface tilt adjustment of the mirror surface 20 of the polygon mirror 7 can be performed with high accuracy.

  Further, in this embodiment, since the point where the adjusting screw 14 contacts the upper rigid plate 11 is located immediately above the point where the elastic member 9 contacts the lower rigid plate 19, the force point applied to the polygon mirror 7 is increased up and down. The direction is substantially the same. For this reason, highly accurate surface tilt adjustment is realized.

Another embodiment of the present invention will be described in detail with reference to FIGS.
3 is a side sectional view of the optical deflector, and FIG. 4 is a plan view of a rotating body of the optical deflector in FIG. For the sake of easy understanding, the fixed shaft is not shown in cross section in FIG. Further, the same parts as those of the optical deflector according to the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  The optical deflector according to the second embodiment is different from the first embodiment only in that the number of adjusting screws is three.

  As shown in FIG. 4, the adjustment screw 14 is attached to the pressing member 6 at equal intervals of 120 ° on a line connecting the ridge line portions 10 between the mirror surfaces 20 and the center of the polygon mirror 7. For this reason, the surface tilt of the polygon mirror 7 can be adjusted by the adjusting screw 14. Further, since the adjustment screw 14 and the mirror surface 20 of the polygon mirror 7 are separated from each other, the deformation of the mirror surface 20 of the polygon mirror 7 due to the pressing force by the adjustment screw 14 can be minimized.

Another embodiment of the present invention will be described in detail with reference to FIGS.
5 is a side sectional view of the optical deflector, and FIG. 6 is a plan view of a rotating body of the optical deflector in FIG. For the sake of easy understanding, the fixed shaft is not shown in cross section in FIG. Also, the same parts as those of the optical deflector according to the second embodiment are denoted by the same reference numerals and the description thereof is omitted.

  The difference between the optical deflector according to the third embodiment and the second embodiment is only that the position of the adjustment screw is positioned inside the center of the mirror surface of the polygon mirror.

  Here, the center inner side of the mirror surface means, as shown in FIG. 6, a position that is equidistant (B = C / 2) from the ridge line portion 10 at both ends of one mirror surface 20 (width C), and a polygon mirror. 7 is a position on the polygon mirror 7 side on a line connecting the centers of 7.

  By providing the adjusting screws 14 at the center inner side of the mirror surface 20 at equal intervals of 120 °, the angle of the mirror surface 20 can be directly adjusted, so that the time for adjusting the surface tilt can be shortened. That is, the mirror surface 20 in the vicinity of the adjustment screw 14 can be adjusted in a short time because the amount of movement of the adjustment screw 14 in the vertical direction is the adjustment amount for the surface inclination of the mirror surface 20 as it is.

Another embodiment of the present invention will be described in detail with reference to FIG.
FIG. 7 is a side sectional view of the optical deflector. For the sake of easy understanding, the fixed shaft is not shown in cross section in FIG. The same parts as those of the optical deflector according to the second or third embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  The only difference from the second or third embodiment of the optical deflector according to the fourth embodiment is that the rigid plates on the upper and lower surfaces of the polygon mirror 7 are eliminated.

  Without the rigid plates 11 and 19, the polygon mirror 7 is deformed at the point where the adjusting screw 14 and the elastic member 9 come into contact with the polygon mirror 7, and the flatness of the mirror surface 20 is deteriorated.

  However, an optical deflector with a gentle specularity of the mirror surface 20 can adopt such a configuration, and can provide an inexpensive optical deflector that can adjust the surface tilt with high accuracy and has a small number of components. be able to.

Another embodiment of the present invention will be described in detail with reference to FIG.
FIG. 8 is a side sectional view of the optical deflector. For the sake of easy understanding, the fixed shaft is not shown in cross section in FIG. Further, the same parts as those of the optical deflector according to the fourth embodiment are denoted by the same reference numerals, and description thereof is omitted.

  The difference between the optical deflector according to the fifth embodiment and the fourth embodiment is only that the number of the adjusting screws 14 is six and that a protrusion having a dimension D is provided at the center of the lower surface of the pressing member. It is.

  While pressing the polygon mirror 7 with the projection 21 formed on the pressing member 46 and pressing and fixing the pressing member 46 to the upper portion of the sleeve 5, the polygon mirror 7 is adjusted while the face is tilted first. The mirror 7 can be fixed to the rotating body 4.

  At that time, if the tips of the six adjusting screws 14 installed on the pressing member 46 at equal intervals of 60 ° are not protruded from the lower surface of the pressing member 46 like the adjusting screw 14 shown on the left side of FIG. The tip of the adjustment screw 14 that is not used for the surface tilt adjustment can always be separated from the upper surface of the polygon mirror 7 by the distance D.

  As a result, it is possible to eliminate the problem that the tip of the adjustment screw 14 that is not used for the face tilt adjustment hits the upper surface of the polygon mirror 7 for some reason, thereby causing the face tilt.

  Needless to say, when adjusting the surface tilt after pressing the polygon mirror 7 with the projection 21 formed on the pressing member 46, the adjustment screw 14 is used (the adjustment screw 14 on the right side in FIG. 8).

Another embodiment of the present invention will be described in detail with reference to FIG.
FIG. 9 is a side sectional view of the optical deflector. In addition, in order to make explanation easy to understand, the fixed shaft is not shown in cross section in FIG. Further, the same parts as those of the optical deflector according to the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  The difference from the first embodiment of the optical deflector according to the sixth embodiment is only that a protrusion having a dimension E is provided on the lower surface of the pressing member.

  In this case, the protrusion 21 formed on the pressing member 46 comes into contact with the upper surface of the upper rigid plate 11, but the upper rigid plate 11, the polygon mirror 7 and the lower rigid plate 19 are brought to the flange 8 side by the pressing member 46. Since the pressing is performed, the same effect as that of the fifth embodiment can be obtained in this embodiment.

A seventh embodiment according to the present invention will be described with reference to FIGS.
10 is a side sectional view of the optical deflector, and FIG. 11 is a plan view of a rotating body of the optical deflector in FIG. In addition, in order to make explanation easy to understand, in FIG.

  The difference between the optical deflector according to the seventh embodiment and the first embodiment is that the first embodiment is an optical deflector in which the sleeve rotates, whereas the optical deflector in the present embodiment has a type in which the rotating shaft rotates. It is a point which is a deflector.

  That is, as shown in FIG. 10, the optical deflector 31 is fixed to the housing 2 with an adhesive or the like, and has a bearing 35 having two bearings 23 therein, and a rotating body rotatably supported by the bearing 35. 34.

  The rotating body 34 includes a rotating shaft 22 rotatably supported by two bearings 23, a flange 38 fixed on the upper portion of the rotating shaft 22, and a ring-shaped leaf spring placed on the flange 38. Elastic member 9, a lower rigid plate 19 placed on the elastic member 9, a polygon mirror 7 having a large number of mirror surfaces 20 formed on the outer peripheral surface placed on the lower rigid plate 19, and the polygon mirror 7, an upper rigid plate 11 placed on the upper side of the flange 38, a pressing member 6 that is forcibly inserted into the upper portion of the flange 38 by press-fitting or shrink fitting, and a drive magnet 12 that is fixed to the flange 38 with an adhesive or the like. Has been.

  A gap is provided on the outer peripheral surface of the flange 38 facing the inner peripheral surface of the polygon mirror 7. The gap is set such that the inner peripheral surface of the polygon mirror 7 does not contact the outer peripheral surface of the flange 38 facing the inner peripheral surface of the polygon mirror 7 even when the polygon mirror 7 is adjusted to be inclined. In this embodiment, a gap of 10 to 30 microns is provided.

  The ring-shaped pressing member 6 is provided with six screw holes at an interval of approximately 60 degrees, and an adjustment screw 14 is attached to each of the screw holes. The tip of the adjustment screw 14 is in contact with the upper surface of the upper rigid plate 11.

  As shown in FIG. 11, the adjustment screw 14 is located on a line connecting the ridge line portions 10 between the mirror surfaces 20 and the center of the polygon mirror 7. For this reason, since the mirror surface 20 is separated from the adjustment screw 14, the deformation (deterioration of flatness) of the mirror surface 20 of the polygon mirror 7 due to the pressing force by the adjustment screw 14 can be minimized.

  By rotating at least one of these six adjusting screws 14 in either the left or right direction, the entire polygon mirror 7 is tilted in the direction A in FIG. ) Can be fine-tuned.

  At this time, since the elastic member 9 is under the lower rigid plate 19 attached to the lower surface of the polygon mirror 7, when the adjustment screw 14 is rotated to the right to bring the tip of the adjustment screw downward, the elastic member 9 The amount of deformation increases. That is, the elastic member 9 is deformed in a direction to be crushed. Further, when the adjustment screw 14 is rotated counterclockwise and the tip of the adjustment screw is retracted upward, the deformation amount of the elastic member 9 is reduced. That is, the elastic member 9 is deformed in the direction in which it returns.

  As described above, when the adjustment screw 14 is rotated right or left and the tip of the adjustment screw 14 is moved downward or upward, the elastic member 9 is deformed according to the amount of movement of the tip of the adjustment screw 14. The mirror 7 itself is not deformed, and the mirror surface accuracy of the polygon mirror 7 is not affected by the adjustment work of the surface tilt.

  As described above, the present invention is applicable not only to the optical deflector of the type in which the sleeve shown in the first embodiment rotates but also to the optical deflector of the type in which the rotating shaft shown in the present example rotates. Can do.

Another embodiment of the present invention will be described in detail with reference to FIGS.
12 is a side sectional view of the optical deflector, and FIG. 13 is a plan view of a rotating body of the optical deflector in FIG. In order to make the explanation easy to understand, the rotating shaft is not shown in cross section in FIG. Further, the same parts as those of the optical deflector according to the seventh embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  The optical deflector according to the eighth embodiment is different from the seventh embodiment only in that the number of adjusting screws is three and the adjusting screws are positioned inside the center of the mirror surface of the polygon mirror.

  As shown in FIG. 13, the three adjusting screws 14 are positioned equidistantly (B = C / 2) from the ridge line portion 10 existing at both ends of one mirror surface 20 (width C), and the polygon mirror 7. They are attached at equal intervals of 120 ° at positions on the polygon mirror 7 side on the line connecting the centers.

  With this configuration, the angle of the mirror surface 20 can be changed directly, so that the surface tilt adjustment time can be shortened.

Another embodiment of the present invention will be described in detail with reference to FIG.
FIG. 14 is a side sectional view of the optical deflector. For easy understanding, the rotating shaft is not shown in cross section in FIG. Further, the same parts as those of the optical deflector according to the seventh embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  The optical deflector according to the ninth embodiment is different from the seventh embodiment only in that the pressing member is fixed to the flange with a screw and the upper rigid plate is pressed downward with the pressing member.

  With this configuration, by fixing the pressing member 36 to the flange 38 with the screw 24, the upper rigid plate 11, the polygon mirror 7, and the lower rigid plate 19 can be fixed to the flange 38 by the elastic force of the elastic member 9.

  At the same time, since the pressing member 36 is in contact with the lower surface of the flange 38, the initial surface tilt adjustment of the mirror surface 20 of the polygon mirror 7 can be performed.

  If the subsequent tilt adjustment is unnecessary, the upper surface of the upper rigid plate 11 and the tip of the adjustment screw 14 can be separated from each other like the adjustment screw 14 on the left side of FIG. As a result, the tip of the adjustment screw 14 that is not used for the surface tilt adjustment hits the upper surface of the upper rigid plate 11 for some reason, thereby eliminating the problem of causing the surface tilt of the mirror surface 20.

  Needless to say, when the face tilt is adjusted after pressing the polygon mirror 7 or the like with the pressing member 36, the adjustment screw 14 is used (the adjustment screw 14 on the right side in FIG. 14).

  In the present embodiment, the screw portion of the adjustment screw 14 may be locked. In this case, since the nylon resin is welded to the screw portion of the adjustment screw, the adjustment screw 14 does not rattle. For this reason, the surface tilt adjustment of the mirror surface 20 of the polygon mirror 7 can be performed with high accuracy.

  Further, in this embodiment, since the point where the adjusting screw 14 contacts the upper rigid plate 11 is located immediately above the point where the elastic member 9 contacts the lower rigid plate 19, the force point applied to the polygon mirror 7 is increased up and down. The direction is substantially the same. For this reason, highly accurate surface tilt adjustment is realized.

Another embodiment of the present invention will be described in detail with reference to FIGS.
15 is a side sectional view of the optical deflector, and FIG. 16 is a perspective view of the upper rigid plate. In addition, in order to make explanation easy to understand, in FIG. The same parts as those of the optical deflector according to the ninth embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  The optical deflector according to the tenth embodiment is different from the ninth embodiment only in that a protrusion is formed at the center of the lower surface of the pressing member and the polygon mirror 7 is pressed by the protrusion.

  In the ninth embodiment, since the upper rigid plate 11 is pressed by the pressing member 36, the processing accuracy of the upper rigid plate 11 affects the surface tilt of the mirror surface 20. However, in the tenth embodiment, since the pressing member 37 directly presses the polygon mirror 7, even when the upper rigid plate 26 is provided on the polygon mirror 7, the processing accuracy of the upper rigid plate 26 is improved. Does not affect the tilting of the mirror surface 20 of the polygon mirror 7.

  The upper rigid plate 26 is preferably provided with a plurality of protrusions 27 as shown in FIG. This is because, when there is an adjustment screw 14 that does not adjust the tilt of the face, such as the adjustment screw 14 shown on the left side of FIG. 15, there is a place where the adjustment screw 14 does not press the upper rigid plate 26. This is because the upper rigid plate 26 flutters and the rotational performance of the rotating body 4 is deteriorated.

  As shown in FIG. 16, the upper rigid plate 26 can be fixed between the polygon mirror 7 and the pressing member 37 by providing the upper rigid plate 26 with a plurality of protrusions 27. Needless to say, the adjustment screw 14 should avoid the protrusion 27 and press the upper rigid plate 26.

Another embodiment of the present invention will be described in detail with reference to FIG.
FIG. 17 is a side sectional view of the optical deflector. In order to make the explanation easy to understand, the rotating shaft is not shown in cross section in FIG. The same parts as those of the optical deflector according to the ninth embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  The difference from the ninth embodiment of the optical deflector according to the eleventh embodiment is that the heads of the screws for fixing the flange and the adjusting screws for adjusting the surface tilt are chamfered.

  With this configuration, it is possible to reduce windage loss caused by the head of the adjustment screw 14 protruding from the upper surface of the pressing member 36.

Another embodiment of the present invention will be described in detail with reference to FIG.
FIG. 18 is a side sectional view of the optical deflector. In order to make the explanation easy to understand, the rotating shaft is not shown in cross section in FIG. The same parts as those of the optical deflector according to the tenth embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  The difference from the tenth embodiment of the optical deflector according to the present twelfth embodiment is only that a counterbore is provided at a position where the adjustment screw is attached to the pressing member, and the head of the adjustment screw is buried in the counterbore. is there.

  With such a configuration, the heads of the adjustment screw 14 and the screw 24 do not protrude from the upper surface of the pressing member 40, so that windage loss caused by the adjustment screw 14 and the screw 24 can be reduced. This is because if the heads of the adjusting screw 14 and the screw 24 protrude from the upper surface of the pressing member, air resistance is generated, which becomes a negative factor for the rotation of the rotating body.

  The above-described embodiments have been illustrated for the purpose of explanation, and the present invention is not limited thereto. Those skilled in the art will recognize from the claims, the detailed description of the invention, and the drawings. Modifications and additions can be made without departing from the technical idea of the present invention.

  For example, in the above-described embodiment, the polygon mirror 7 having six mirror surfaces is shown. However, not only the six polygon mirrors but also five or eight surfaces may be used. Further, the number of adjustment screws is three or more, and may be any number that is an integer when the number of mirror surfaces 20 of the polygon mirror is divided by the number of adjustment screws. Other than three or six. May be.

  For example, 8 or 4 polygon mirrors with 8 mirror surfaces, 9 or 3 polygon mirrors with 9 mirror surfaces, 12 polygon mirrors with 12 mirror surfaces , 6, 4 or 3.

  Moreover, although the above-mentioned Example showed the optical deflector of the type with which a rotating shaft rotates, and the optical deflector of the type with which a sleeve rotates, the elastic member which is the fundamental structure of this invention, a lower rigid board, The point which uses a polygon mirror, an upper rigid board, a press member, and an adjustment screw is common. Therefore, the invention described in the case of the optical deflector in which the rotating shaft rotates is not described in the case of the optical deflector in which the sleeve rotates, or the invention described in the optical deflector of the type in which the sleeve rotates. However, this basic configuration can be implemented by both optical deflectors.

  For example, the structure of providing the counterbore on the pressing member described in the twelfth embodiment has not been described in the optical deflector of the type in which the sleeve rotates, but it can also be implemented in such an optical deflector. The effect that can be reduced can be obtained.

  In the present invention, a gap is provided between the outer peripheral surface of the sleeve or the flange and the inner peripheral surface of the polygon mirror. In order to maintain the state after the surface tilt adjustment for a long period of time, an adhesive is poured into this gap. The polygon mirror may be firmly fixed to the sleeve. Further, a UV adhesive may be used as the adhesive.

  Furthermore, in the above-described embodiment, an optical deflector in which a thrust magnetic bearing is constituted by only the coil 16 and the drive magnet 12 is shown. For example, a magnetic body is provided on the upper end portion of the fixed shaft 3 and the upper end portion of the sleeve 5 is provided. A thrust magnetic bearing may be configured by providing a thrust magnet on the surface.

  In the above-described embodiment, the tip of the adjustment screw 14 is flat. However, from the viewpoint of easy adjustment of the surface tilt, the tip of the adjustment screw 14 may be spherical. desirable. This is because if the tip of the adjustment screw 14 is flat, the polygon mirror or the upper rigid plate will be pressed by the surface, but if the tip of the adjustment screw is a sphere (hemisphere), the polygon mirror or the upper rigid plate will be pressed by a point. Because it will do.

  The present invention is applied to an optical deflector used in an image forming apparatus or the like.

(Example 1) which is side sectional drawing of the optical deflector which concerns on this invention. (Example 1) which is a top view of the rotary body of the optical deflector which concerns on this invention. (Example 2) which is side sectional drawing of the optical deflector which concerns on this invention. (Example 2) which is a top view of the rotary body of the optical deflector which concerns on this invention. (Example 3) which is side sectional drawing of the optical deflector which concerns on this invention. (Example 3) which is a top view of the rotary body of the optical deflector which concerns on this invention. (Example 4) which is side sectional drawing of the optical deflector which concerns on this invention. (Example 5) which is side sectional drawing of the optical deflector which concerns on this invention. (Example 6) which is side sectional drawing of the optical deflector which concerns on this invention. (Example 7) which is side sectional drawing of the optical deflector which concerns on this invention. (Example 7) which is a top view of the rotary body of the optical deflector which concerns on this invention. (Example 8) which is side sectional drawing of the optical deflector which concerns on this invention. (Example 8) which is a top view of the rotary body of the optical deflector which concerns on this invention. (Example 9) which is side part sectional drawing of the optical deflector which concerns on this invention. (Example 10) which is side part sectional drawing of the optical deflector which concerns on this invention. (Example 10) which is a perspective view of an upper rigid board. (Example 11) which is side sectional drawing of the optical deflector which concerns on this invention. (Example 12) which is sectional drawing of the side part of the optical deflector which concerns on this invention. It is side part sectional drawing explaining the conventional optical deflector.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical deflector 2 Housing 3 Fixed shaft 4 Rotating body 5 Sleeve 6 Press member 7 Polygon mirror 8 Flange 9 Elastic member 10 Ridge part 11 Rigid board 12 Drive magnet 14 Adjustment screw
19 Rigid plate 20 Mirror surface 21 Projection

Claims (9)

A sleeve rotatably attached to the outside of the fixed shaft;
A flange fixed to the sleeve;
An elastic member placed on the flange;
A polygon mirror mounted on the elastic member and having a plurality of mirror surfaces;
A pressing member fixed to the sleeve at an upper portion of the polygon mirror and having a plurality of adjusting screws attached in parallel to the fixed shaft;
In the optical deflector in which the tip of the adjustment screw is brought into contact with the upper surface of the polygon mirror and the polygon mirror is pressed against the flange side,
The number of adjustment screws is three or more, and is a number that becomes an integer when the number of mirror surfaces of the polygon mirror is divided by the number of adjustment screws,
The optical deflector characterized in that the adjustment screw is attached to the pressing member at equal intervals. A rotating shaft rotatably mounted inside the bearing;
A flange fixed to the rotating shaft;
An elastic member placed on the flange;
A polygon mirror mounted on the elastic member and having a plurality of mirror surfaces;
A pressing member fixed to the flange at an upper portion of the polygon mirror and having a plurality of adjusting screws attached in parallel to the fixed shaft;
In the optical deflector in which the tip of the adjustment screw is brought into contact with the upper surface of the polygon mirror and the polygon mirror is pressed against the flange side,
The number of adjustment screws is three or more, and is a number that becomes an integer when the number of mirror surfaces of the polygon mirror is divided by the number of adjustment screws,
The optical deflector characterized in that the adjustment screw is attached to the pressing member at equal intervals.   The optical deflector according to claim 1, wherein an upper rigid plate is provided on the upper surface of the polygon mirror, and a lower rigid plate is provided on the lower surface of the polygon mirror. The pressing member has a protrusion formed at the center of the lower surface,
The optical deflector according to claim 1, wherein the protrusion is placed on the polygon mirror or the upper rigid plate.   The light deflection according to any one of claims 1 to 4, wherein a tip of the adjustment screw is located on each line connecting each ridge line portion between each mirror surface of the polygon mirror and the center of the polygon mirror. vessel   The optical deflector according to any one of claims 1 to 5, wherein a tip of the adjustment screw is located inside a center of the mirror surface of the polygon mirror.   The optical deflector according to claim 1, wherein the adjustment screw is locked. The pressing member is provided with a counterbore at a location where the adjustment screw is attached,
The optical deflector according to claim 1, wherein the head of the adjustment screw is buried in the spot facing.   9. The point according to claim 1, wherein the point where the adjustment screw contacts the polygon mirror or the upper rigid plate is located directly above the point where the elastic member contacts the polygon mirror or the lower rigid plate. Optical deflector as described in

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