JPH04149401A - Mirror holder - Google Patents

Abstract

PURPOSE:To prevent a mirror from deforming and vibrating with simple structure by providing a member which restrains flexural vibration perpendicular to the reflecting surface of the mirrors near the center of the mirror. CONSTITUTION:The restraint member 7 which contacts side parts facing the reflecting surfaces of the mirrors 5 and 6 and is pressed in a direction parallel to the reflecting surfaces is used and held so that the movement of the member 7 perpendicular to the mirror reflecting surfaces is restrained. When the mirrors 5 and 6 are used, the restraint member 7 is used while the side parts of the opposite or adjacent mirrors 5 and 6 are coupled to restrain the movement perpendicular to the reflecting surfaces. The restraint member 7 is held between the mirrors 5 and 6 and structure members 7b and 7c at their peripheries and is arranged so as to have high rigidity at right angles to the reflecting surfaces of the mirrors 5 and 6. Consequently, the influence of the initial deformation of the mirrors 5 and 6 is reduced with the simple structure and the mirrors 5 and 6 are prevented effectively from deforming and vibrating owing to vibration and shock.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a mirror holding device for an optical device having a mirror.

[Conventional technology]

In devices that perform recording or reading by optical scanning, mirrors are often used to convert the optical path and change the direction, or to downsize the entire optical system.The mirrors used in such devices require high precision. You must also pay attention to the installation method, that is, the mirror itself
It is necessary to have a structure that does not cause problems such as deformation, vibrations, deviations, etc. due to external vibrations, collisions, etc., and changes in the optical path and angle of view. In particular, when a plurality of mirrors are used, the relative positional accuracy of the mirrors must be taken into consideration.As for such a device, the technique disclosed in Japanese Patent Publication No. 62-23844, for example, is known.

[Problem to be solved by the invention]

In the optical device as described above, a slight deformation of the mirror generally causes an error in the optical path, which becomes large enough to be ignored on the scanning plane. Particularly, when the amount of deformation changes due to vibrations or the like, vertical undulations occur in the read or recorded image, making the permissible value of variation strict.

Furthermore, when repetitive scanning is performed to record or read a high-quality image or to record or read a color image, the image quality deteriorates and one color shift occurs.

For the purpose of stably obtaining the precision of the mirror surface itself at a relatively low cost, it is a good idea to use a glass plane mirror and to use a plurality of them in combination as necessary. It is clear that an improvement can be obtained by making the shape of the mirror stronger by increasing its thickness, but this results in an increase in mass and an increase in the size of the device.

SUMMARY OF THE INVENTION In view of the above-mentioned problems, an object of the present invention is to provide a high-precision holding device that has a simple configuration and can prevent deformation and vibration of a mirror.

[Means to solve the problem]

Since the mirror of the above-mentioned device uses the central part as a functional part, it is usually supported at both ends. Therefore, since the maximum displacement of deformation and vibration occurs at the center of the mirror,
It is clear that it is advantageous to provide means for restraining the central portion of the mirror.

If the central portion is supported in addition to the support at both ends, the mirror will be supported at four or more points, making it impossible to obtain stable precision. Furthermore, if a load is applied to the mirror in a direction perpendicular to its reflective surface and the mirror is held, the mirror will bend.

On the other hand, the spring constant of the above-mentioned holding member needs to be sufficiently large in response to deflection vibration of the mirror. This is because if the deflection of the mirror itself is approximately the same as the equivalent spring constant, the natural frequency of the mirror will change, which is not a fundamental solution.

In order to solve the above-mentioned problems and achieve the above-mentioned purpose, the following structure is adopted.

In other words, a regulating member is used that is in contact with the side of the reflective surface of the mirror and is pressed in a direction substantially parallel to the reflective surface, and the regulating member is held so as to restrict the movement of this member in a direction perpendicular to the reflective surface of the mirror. do. When using a plurality of mirrors, the above-mentioned regulating member is used to connect the sides of opposing or adjacent mirrors.

Restricts movement in the direction perpendicular to the reflective surface. This regulating member is held between the mirror and the surrounding structural members, and
The mirror is arranged to have high rigidity in the direction perpendicular to the reflective surface of the mirror.

[Effect]

The regulating member is brought into frictional contact at one or both of the contact section with the mirror and the contact section with the structural material. At this time, the pressing is performed in a direction such that the component force in the direction perpendicular to the reflective surface of the mirror is small, thereby minimizing deformation of the mirror. Further, by pressing the side surfaces, the mirror is held substantially at both ends of the original mirror, ensuring precision and stability of placement.

In response to external collisions and vibrations, within the range of the static friction force of the contact area mentioned above, it will be rigidly held against the structural material, and if displacement occurs beyond this range, it will be quickly damaged due to friction loss. It has the function of attenuating the

In addition, in the case of a plurality of mirrors, the mirrors held in a connected manner have the above function and synchronize the phases of displacement, thereby reducing changes in the optical path due to deformation (vibration) of the mirrors.

Furthermore, since the above-mentioned pressing force is mainly applied in a direction parallel to the reflective surface of the mirror, the influence of deformation of the mirror can be reduced.

〔Example〕

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

FIG. 1 is a diagram showing an example in which the present invention is applied to a scanning optical system of a laser printer. This laser printer focuses laser light onto a minute spot and scans the photoreceptor 13 to form an image. Electrophotographic processes such as charging, development, and transfer are arranged around the circumference of the photoreceptor 13 to print on paper.

A light beam emitted from a laser diode unit 2 having a laser diode 2a and a collimator 2b is deflected by a polygon mirror motor 3, and an image is formed on a drum-shaped photoreceptor 13 by an fθ lens 4. Since the arrangement of lenses and the like requires sufficient precision, they are housed in an integrated housing 1. The light beam 14 uniformly scans the photoreceptor 13 from the scanning start side 14a to the scanning end side 14b. In this embodiment, two mirrors 5 and 6 are used to make the entire optical system compact and to guide the light beam to a predetermined position on the photoreceptor.

The mirrors 5 and 6 are placed on a support stand 8-1, 8-2 and held at a predetermined position and angle by presser springs 9 (four pieces). Note that the support stand 8-1, 8-2 and the housing 1 that accommodates the above-mentioned lenses and the like are fixed to the base 11.

A part of the mirror is provided with an upper cover 12 made of a steel plate, a lower cover 10 and a dustproof glass 15 are provided for the light beam exit, and a sealing material 16 is provided between the housing 1 and the upper cover 12. This makes the entire structure airtight and prevents dust from entering from the outside. In addition, in FIG. 1, the plan view is shown with the above-mentioned upper cover 12 removed.

Here, a vibration isolating plate 7 is placed so as to come into contact with the sides of the mirrors 5 and 6.
Set up. The vibration isolating plate 7 is made of a spring material, and the upper cover 12 presses a partially bent plate spring portion 7a. This allows the mirror to be moved to the abutting portions 7b, 7 of the vibration isolating plate.
c. The contact portion between the leaf spring and the upper cover 12 comes into frictional contact.

The length of mirrors 5 and 6 is approximately 260 m, and in order to evaluate the effect of mirror deformation, a
Assuming that a load of 0.00 g (0.98 N) is applied, the deflection of the mirror will be approximately 27 μm at the center. The optical path length between the mirror 5 and the photoreceptor 13 is approximately 185 degrees, and due to the above-mentioned deflection, the length of the optical path between the mirror 5 and the photoreceptor 13 is approximately 185 mm.
The upper scan width changes by about 0.1 mm. On the other hand, the deterioration of the spot shape due to changes in the flatness of the mirror can be almost ignored. Therefore, normally it is sufficient to consider the influence of the change in the scanning width. In this embodiment, the displacement of the mirror is restrained within the range of static friction force, and the displacement due to vibration etc. is converted into heat by the friction of the contact part. Dissipate. Further, the position of the vibration isolating plate 7 is maintained by bending the side that contacts the mirror and the pressure force of the upper cover 12, and the contact portion 7b with the mirror.

7c may be fixed by connection, adhesive tape, etc. However, according to experiments, it is necessary that the spring constant of the fixing material in the shear direction is sufficiently large.

Moreover, fixing both 7b and 7c is not preferable because it will give the mirror initial deflection deformation during assembly work. By selecting a material for the vibration isolation plate 7 to have a coefficient of thermal expansion comparable to that of the support base 8-1, 8-2, deflection of the mirror due to the difference in coefficient of thermal expansion can be minimized. In this embodiment, the support bases 8-1, 8-2 are ordinary steel plates, and the vibration isolation plate 7 is a spring stainless steel plate.

As described above, in this embodiment, the side parts of the two mirrors are connected and controlled by one vibration isolating plate, and a part of the vibration isolating plate acts as a spring to prevent vibration between the two mirrors and the cover. Since it is pressed, it is possible to perform a very effective suppression effect, especially against vibrations, with a simple configuration.

FIG. 2 shows another embodiment in which the mirror is one
A cross section of the main part in the case of a sheet will be explained. A scanning light beam 106 incident from the left side of the figure is reflected by the mirror 102 and converted to the lower left side.

Mirror 102 is held on mirror support 105 by a push spring 103 similar to that shown in FIG.

Furthermore, the mirror support stand 105 is fixed to the base 101. A vibration isolation plate 104 is fixed to the over 107 with rivets 108. In this embodiment, the vibration isolating action is performed by the contact portion 104a between the vibration isolating plate 104 and the mirror 102,
Effects similar to those of the previous embodiment can be obtained.

FIG. 3 shows an example in which the same method as in the second embodiment is applied to a case where there are two mirrors, and the mirror support stand and the mirror pressing spring are the same as in the first embodiment. . In this embodiment, the vibration isolating plates 112 and 113 are connected to the cover 114.
are fixed with rivets 116 to form an integral structure, and the abutting portion between the vibration isolating plate and the mirror performs the above-mentioned action. In this embodiment, the number of parts is increased compared to the first embodiment, but the degree of freedom in arranging the mirrors is increased, and effective image stabilization can be performed with respect to various forms of mirror arrangement.

Although this embodiment shows the case where there are two mirrors, the same effect can be obtained even if there are three or more mirrors. Furthermore, in this embodiment, the vibration isolating plate is fixed to the upper cover 114;
Depending on the arrangement of the mirror and how to take the optical path, it may be fixed to another member, for example, the base 109 in this embodiment, or a member may be newly provided to connect the supporting members and fixed to this member. good.

FIG. 4 is a diagram showing still another embodiment.

In the first embodiment, the vibration isolating plate 120 and the spring 118 are made separately, whereas the vibration isolating plate 120 and the spring 118 are made separately and connected with screws 121.

The mirrors 110', 111', base 109' and support plate are the same as in the third embodiment.

In the above embodiments, the pressing force of the vibration isolating plate is:

It has been confirmed that it is effective at about 100 g (IN), and that the position of the vibration isolating plate has a tolerance of about 20 degrees in the longitudinal direction of the mirror.

〔Effect of the invention〕

As explained above, according to the present invention, by pressing the side part near the center of the mirror supported near both ends mainly in the direction parallel to the reflecting surface, and using a holding member having rigidity in the direction perpendicular to the reflecting surface. With a simple configuration, deformation and vibration of the mirror due to vibration and impact can be effectively prevented, while the influence of initial deformation of the mirror is reduced, and recording or reading accuracy can be improved.

[Brief explanation of drawings]

FIGS. 1(a) and (b) are a plan view and a main sectional view showing an embodiment of the present invention, FIG. 2 is a sectional view showing the main part of an embodiment with one mirror, and FIG. 3 4 is a sectional view showing the main part of another embodiment, and FIG. 4 is a sectional view showing the main part of still another embodiment. 2... Laser diode unit, 3... Polygon motor, 4... fθ lens, 5, 6... Mirror, 7
... Vibration proof plate, 13... Photoreceptor, 102... Mirror 104... Vibration proof plate, 105... Support plate, 110
,111,110'111'...Mirror, 112,1
13...Vibration isolation plate, 114.119...Cover Fig. 1 (b) 1-1-1 Town, Hitachi Seisakusho Co., Ltd.

Claims (1)

[Claims] 1. In a mirror holding device in which the vicinity of both ends of the mirror are supported by mirror support members, a member is provided near the center of the mirror for regulating flexural vibration in a direction perpendicular to the reflective surface of the mirror. A mirror holding device characterized by: 2. In a mirror holding device in which the vicinity of both ends of a pair of mirrors are supported by mirror support members, a regulation member is provided near the center of the mirrors to regulate the relative deflection of the mirrors, and the regulation member further 1. A mirror holding device, characterized in that the mirror supporting member and a structural member substantially connected thereto are restricted from moving relative to each other in the vicinity of the mirror supporting member. 3. In claim 2, the regulating member is in contact with the side of the mirror and presses in a direction such that a component of force in a direction parallel to the opposite surface of the mirror is larger than a component of force in a direction perpendicular to the opposite surface of the mirror.
A mirror holding device, characterized in that the device acts rigidly against deflection in a direction perpendicular to the reflective surface of the mirror between the structural member and the contact portion slides. 4. The mirror holding device according to claim 2 or 3, wherein the regulating member is made of a material having substantially the same coefficient of thermal expansion as that of the mirror supporting member. 5. In claim 2, 3 or 4, the predetermined position;
A mirror holding device characterized in that a mirror held at an angle is held so as to resist the deformation of a portion near a portion where the amount of displacement is maximum.