JPH0829720A - Mounting structure for rotary polygon mirror - Google Patents

Abstract

PURPOSE:To provide the mounting structure of a rotary polygon mirror which copes with the quick rotation and weight increase of a rotary polygon mirror and where full aligning is made by simple and light constitution. CONSTITUTION:When a change is caused at the space (s) of an engaging part of the rotary polygon mirror 1 having an oblique notched part at the upper part of the inside diameter of a hole made at a center and a rotary shaft 2 having a flange part being orthogonal to a shaft, an elastic member 4 pushes an aligning member 3 into a groove constituted of the wall surface of the rotary shaft 2 and the notched part, and the space (s) is substantially filled. Thus, the need of filling the interstice (s) by packing adhesive or the like and increasingly tightening a screw 5 used for mounting the rotary polygon mirror 1 are eliminated compared with a preceding technology, so that the deviation of an axial center is prevented without deforming the rotary polygon mirror 1. Also, even if starting and stopping are repeated, the aligning member 3 is pushed in the groove in despite of the change of the groove, so that the deviation is not accumulated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary polygon mirror used in a copying machine or a laser printer, and more particularly to a rotary polygon mirror for fixing the rotary polygon mirror to the rotary shaft of a rotary polygon mirror drive motor. Regarding mounting structure.

[0002]

2. Description of the Related Art Conventionally, a rotary polygon mirror has been used in a copying machine, a laser printer or the like, and when the rotary polygon mirror is rotated to scan an image, an error in the rotational speed of the rotary polygon mirror, processing accuracy, etc. Since the vibration occurs depending on the degree, the balance of the rotary polygon mirror was adjusted. However, no matter how much the balance is adjusted, when the rotating polygon mirror is actually rotated, thermal expansion due to centrifugal force or frictional heat with air causes
There is a problem that the rotating polygon mirror and the rotating shaft are deformed and unexpected vibration occurs.

Usually, the rotary polygon mirror is made of a material such as aluminum alloy or resin that is lightweight and relatively weak in rigidity, while the rotating shaft is made of a material such as iron or stainless steel in which relatively rigid is used. The coefficient of thermal expansion of the rotating polygon mirror and the rotating shaft also differs depending on the difference. Therefore, when the rotary polygon mirror and the rotary shaft rotate, the inner diameter of the bearing hole of the rotary polygon mirror may be deformed by δ1 and the outer diameter of the rotary shaft may be deformed by the amount of δ2 due to centrifugal force or thermal expansion generated at that time. Between the rotary polygon mirror and the rotary shaft, in addition to the originally existing gap, a shift corresponding to the difference of δ1-δ2 occurs. As a result, the tightening force of the screw varies, and the force is displaced toward the weak side, which may cause vibration. Further, when the start and stop are repeated, the deviation is accumulated.

In order to solve the above-mentioned problem, as shown in FIG. 4, the rotary polygon mirror 1 is fixed to the flange portion 2'of the rotary shaft 2 by tightening with screws 5 or the like, and the bearing of the rotary polygon mirror 1 is fixed. It has been proposed that a gap s formed by the inner diameter D1 of the hole and the outer diameter D2 of the rotary shaft 2 is filled with a chemical filler such as an adhesive and processed to eliminate the gap s. This prior art is disclosed, for example, in Japanese Utility Model Laid-Open No. 59-156216.

Further, as a prior art, the utility model Sho 61-16
There is a "polygon mirror mounting structure" disclosed in Japanese Patent No. 0419. In this prior art, as shown in FIG. 5, an O-ring-shaped elastic member 11 is embedded as an aligning member in an annular groove formed between the rotary polygon mirror 1 and the rotary shaft 2, and the elastic member 11 The rotary polygon mirror 1 is mounted coaxially with the rotating shaft 2 by pressing the pressing member 12 and 13 against the receiving seat 14 axially attached to the rotating shaft 2.

As another prior art, Japanese Patent Laid-Open No. 2-1
There is a "polygon mirror engagement method" disclosed in Japanese Patent No. 70113. In this prior art, as shown in FIG. 6, a tapered engagement hole of a resin-molded rotary polygon mirror 1 and a tapered surface of a holding plate 15 as an aligning member are engaged with each other, and one end of a stopper 18 is provided. Even if the clearance between the rotary polygon mirror 1 and the rotary shaft 2 changes, the pressing member 15 is elastically pressed toward the pedestal 17 fixed to the rotary shaft 2 by the spring member 16 locked to the rotary shaft 2. , So that this change can be corrected.

[0007]

In recent years, rotary polygon mirrors have been
The rotating polygon mirror used in a copying machine or a laser printer has a higher scanning speed. Further, there is an increasing demand for irradiating one rotating polygon mirror with a plurality of beams in accordance with the increase in the number of colors, and the weight of the rotating polygon mirror is increasing. Therefore, when the image is scanned, the image is affected even if the rotary polygon mirror deviates from the axial center by only a few microns, so the balance of the rotary polygon mirror must be adjusted in units of several microns.

However, as described with reference to FIG. 4, when the adhesive is filled in the gap formed by the inner diameter of the bearing hole of the rotary polygon mirror and the outer diameter of the rotary shaft, the gap expands due to thermal expansion or centrifugal force. At this time, due to the variation in the adhesive force in the radial direction, it tends to be pulled toward the stronger adhesive force, which causes a problem that the axial center is displaced.

Further, in the prior art described with reference to FIG. 5, it is possible to prevent the displacement of the rotary polygon mirror to some extent, but since the aligning member is made of an elastic body, it seems that the rotary polygon mirror is required. There is a problem that it is not possible to prevent a deviation of only a few microns.

Further, in the prior art described with reference to FIG. 6, it is difficult to set the axis of the spring itself and to align the spring with the axis of the rotary polygon mirror, so that the elastic force of the spring alone is used for pressing. There is a problem that the holding plate cannot sufficiently fulfill the role of the centering member.

The object of the present invention is to eliminate the above-mentioned problems of the prior art, to cope with high-speed rotation of the rotary polygon mirror and to increase the weight of the rotary polygon mirror, and with a simple and lightweight structure, sufficient adjustment is achieved. It is to provide a mounting structure for a rotating polygon mirror that can be focused.

[0012]

In order to achieve the above object, the present invention provides a rotary polygon mirror having an oblique notch in the inner diameter upper part of a hole formed in the center, a wall surface of the rotary shaft and the notch. An aligning member placed in a groove formed by the
And a pressing member for pressing the aligning member.

[0013]

According to the present invention, the aligning member is pressed by the pressing member, and is formed in the groove formed by the wall surface of the rotating shaft and the notch provided in the upper portion of the inner diameter of the hole formed in the center of the rotating polygon mirror. By being pushed in, it becomes possible to substantially fill the gap formed between the inner diameter of the hole of the rotating polygon mirror and the wall surface of the rotating shaft.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a configuration diagram showing a mounting structure of a rotary polygon mirror according to a first embodiment of the present invention. 1A is a plan view and FIG. 1B is a sectional view taken along line AA. FIG. 2 is a partially enlarged view of the configuration showing the features of this embodiment. In the figure, 1 is a rotary polygonal mirror with a hole for attaching a rotary shaft formed in the center, 2 is a rotary shaft provided with a flange portion 2 ', 3 is an aligning member, for example, a cut portion at a part thereof. A steel ring provided with 3 ', 4 is an elastic body, for example, ring 3
A flat plate ring-shaped leaf spring 5 that uniformly presses is a screw for fixing the rotary polygon mirror 1 and the leaf spring 4 to the flange portion 2 ′.

The rotary polygon mirror 1 is fitted on a rotary shaft 2 as shown in the drawing, and is fixed to a flange portion 2'with a leaf spring 4 and a screw 5. The rotary polygon mirror 1 and the rotary shaft 2
In consideration of the assemblability, a gap s as shown in FIG. The gap s is a gap in a state where the rotary polygon mirror 1 and the rotary shaft 2 are stationary and are not affected by heat or the like.

Further, the inner diameter of the hole formed in the rotary polygon mirror 1 is provided with a taper portion notched at an angle θ,
The tapered portion and the wall surface of the rotating shaft 2 form a groove having a triangular cross section. The ring 3 fitted in the triangular groove is pressed into the groove by the claw portion 4 ′ of the leaf spring 4.

The ring 3 is, for example, SUS304SW.
It is made of P or the like, and is made of a wire rod having a thickness that does not bury it in the groove. In addition, the ring 3 is the cut point 3
′ Is provided, and the ring diameter can be freely changed within the elastic range. That is, it is possible to match the deformation of the rotary polygon mirror 1 or the rotary shaft 2 due to centrifugal force, thermal expansion, or the like.

Next, the aligning action of this embodiment will be described. When the rotary polygon mirror 1 and the rotary shaft 2 rotate, the gap s is generated by centrifugal force, thermal expansion, etc. as described above.
The rotary polygon mirror 1 and the rotary shaft 2 are deformed, and in addition to the gap s, a difference between the amount of deformation of the rotary polygon mirror 1 and the amount of deformation of the rotary shaft is added, and the gap s is expanded to the gap s'. Further, the triangular groove is enlarged along with the enlargement of the gap s.

The ring 3 is uniformly pushed into the groove enlarged by the claw portion 4'of the leaf spring 4, and substantially fills the gap s'. Further, sometimes the balance is not uniformly pushed and the balance is lost, but in this case, when the angle θ is small, as will be described later, the link 3 does not return to the original state after the stop and cooling, so that the rotating multi-face is again rotated. If the balance of the mirror is adjusted, stable alignment can be obtained thereafter. Therefore, as in the prior art shown in FIG. 4, the gap s is filled with an adhesive or the like, or the screw 5 is tightened more than necessary so that the axial center is not displaced. You don't have to hold it down.

Next, when the rotation of the rotary polygon mirror 1 and the rotary shaft 2 is stopped and the rotary polygon mirror 1 and the rotary shaft 2 are cooled, the rotary polygon mirror 1 contracts and the inner diameter of the hole becomes smaller. Therefore, the ring 3 is pushed upward, but this is prevented by reducing the frictional force between the ring 3, the rotary shaft 2 and the tapered portion of the rotary polygon mirror 1 and the angle θ of the tapered portion. It is possible to maintain a well-balanced state, and the axis does not shift. Further, even if the starting and stopping are repeated, the error is not accumulated because the ring 3 is pushed in regardless of the change of the triangular groove.

In the present embodiment, the ring 3 has a circular cross-sectional shape as shown in FIGS. 1 and 2, but the present invention is not limited to this, and it may be oval, triangular, quadrangular or polygonal. But it's okay. In the present embodiment, the leaf spring 4 has a claw portion 4
′ Are evenly provided at three places, but the claw portions 4 ′ may be provided at least at two or more places. Also, the claw portion 4 '
It is also possible to remove the connecting portion between them and press the ring 3 only with the claw portions 4 ′ that are fixed by screws 5 and are evenly positioned. Further, the centering member is preferably a ring made of a wire rod, but instead of this, a plurality of steel balls may be used. At this time, it is advisable to form a recess on the side surface of the groove of the claw portion 4'to prevent the steel ball from laterally shifting.

Next, a second embodiment of the present invention will be described with reference to the drawings. FIG. 3 is a sectional view showing the mounting structure of the rotary polygon mirror of the second embodiment. In the figure, reference numeral 6 is a rigid holding plate in the shape of a flat plate that presses the ring 3 evenly. Note that other reference numerals indicate the same or equivalent parts as in FIGS.

In this embodiment, the pressing plate 6 is tightened on the flange portion 2 ′ with the screw 5 so that the pressing plate 6 presses the ring 3 against the rotary polygon mirror 1. As a result, the ring 3 is pushed into the above-mentioned triangular groove, the rotary polygon mirror 1 is pressed against the flange portion 2 ', and the rotary shaft 2
It is fixed coaxially with. According to the second embodiment, the same action and effect as those of the first embodiment can be obtained.

In the present embodiment, the holding plate 6 is a flat ring, but it may have a claw portion similar to the claw portion 4'of FIG. 1 (a). It should be noted that this embodiment may be modified similarly to the first embodiment.

[0025]

As is apparent from the above description, according to the invention of claim 1, when the gap between the fitting portion between the rotary polygon mirror and the rotary shaft changes, the pressing member causes the fitting portion to move. Since the aligning member can be pushed into the groove provided on the upper part of the space to substantially fill the gap, it is possible to fill the gap by filling with an adhesive or the like as in the prior art, or to attach the rotary polygon mirror. Since it is not necessary to re-tighten the rotating polygon mirror, it is possible to prevent the displacement of the axis center without distorting the rotary polygon mirror. Further, even if the starting and stopping are repeated, the ring 3 maintains the pushed state regardless of the change of the groove, so that the error does not accumulate.

Further, according to the second and third aspects of the invention, since the aligning member is lightweight and has high hardness, the inertia of the aligning member itself is small and the bending during rotation is small, so that the aligning member is small. It is not necessary to consider the deviation of the axis center by itself. Further, according to the invention of claim 4, since the pressing member is divided for each portion having the claw portion, a portion for mechanically connecting the claw portion and the claw portion is not necessary, so that the weight is reduced. be able to.

[Brief description of drawings]

FIG. 1 is an AA cross-sectional view showing a mounting structure for a rotary polygon mirror of a first embodiment of the present invention.

FIG. 2 is a partially enlarged view of the configuration showing the characteristic of the first embodiment.

FIG. 3 is a sectional view showing a mounting structure of a rotary polygon mirror of a second embodiment.

FIG. 4 is a sectional view showing a mounting structure of a rotary polygon mirror of a conventional device.

FIG. 5 is a sectional view showing a mounting structure of a rotary polygon mirror of a conventional device.

FIG. 6 is a cross-sectional view showing a mounting structure of a rotary polygon mirror of a conventional device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Rotating polygonal mirror, 2 ... Rotation axis, 3 ... Alignment member, 4 ... Elastic body, 5 ... Screw, 6 ... Holding plate.

Claims (4)

[Claims] 1. A rotary polygonal mirror comprising: a rotary shaft having a flange portion orthogonal to the axis; and a rotary polygonal mirror having a hole in the center thereof. The rotary polygonal mirror is fitted into the rotary shaft and fixed to the flange portion. In the mounting structure, a rotary polygon mirror having an oblique notch in the inner diameter upper portion of a hole opened in the center, an aligning member placed in a groove constituted by the wall surface of the rotating shaft and the notch, A rotary polygon mirror mounting structure comprising: a pressing member that presses the aligning member. 2. The mounting structure for a rotary polygon mirror according to claim 1, wherein the aligning member is a lightweight and highly rigid ring-shaped wire. 3. The rotation according to claim 1, wherein the aligning member is a plurality of light weight and high hardness steel balls, and a recess is provided in a portion of the pressing member for holding the steel balls. Mounting structure for polygon mirror. 4. The pressing member is divided for each part that presses the aligning member.
4. A rotary polygon mirror mounting structure according to any one of 3 to 3.