JPH09191626A - Resonance type scanner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a long-life, small size and high speed resonance type scanner by realizing fixing of a vibrating section of a small size resonance type scanner and a spring for resonance with a simplified structure. SOLUTION: A resonance type scanner comprises a light scanning mirror 4 for reflecting the light such as a laser beam, a vibrating section having a driving permanent magnet 3 for generating a driving force and a holder 2 for fixing such magnet, a spring 1 for resonance, a magnetism generating section using a driving coil 5 which resonates the vibrating section by applying an AC voltage of the resonance frequency and a frame 6 for supporting the resonance spring 1 and driving coil 5. Here, both sides of the resonance spring 1 which will becomes the vibrating axis of the driving permanent magnet 3 are magnetized to N and S poles. In this structure, the resonance spring 1 and holder 2 are fixed to the frame by inserting the resonance spring 1 into two holes opened in the direction to the vibrating axis of the holder 2 and then bending it in the direction to the vibrating axis under the condition that a constant tension is applied in the axial direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compact and high speed resonant scanner used for scanning a laser beam in a laser printer or the like.

[0002]

2. Description of the Related Art Conventionally, there is no small-sized and high-speed resonance type scanner as the object of the present invention, and a large-size resonance type scanner is shown in FIG.
As shown in Fig. 5, the vibrating part including the resonance spring and the optical scanning mirror is integrally press-punched, or Fig. 5
The structure shown in B is generally fixed by brazing, welding, bonding, or soldering.

[0003]

In order to realize a resonance type scanner that is compact and requires a high resonance frequency, the moment of inertia of the vibrating portion including the resonance spring must be reduced. For that purpose, it is required to reduce the weight of the vibrating portion including the optical scanning mirror, the driving permanent magnet and the resonance spring as much as possible. Further, in the case where the angular displacements of the scanning mirrors are the same, in order to use the resonance spring within the allowable stress, the larger the wire diameter, the longer the spring length must be. For these two reasons, a small diameter resonance spring must be used to realize a small and high speed resonance type scanner. Furthermore, in order for the vibrating part including the optical scanning mirror to be stably angularly displaced about the vibrating axis, it is important to apply an appropriate axial tension to the resonance spring, especially when using a resonance spring with a small diameter. Is.

In the case of the conventional fixing method, adhesion or soldering is insufficient in strength to withstand both pulling and twisting forces. Further, the fixing method such as brazing or welding may deteriorate the characteristics of the spring due to heat. Also, if a light metal such as aluminum is used for the base in order to reduce the weight of the vibrating part, it is impossible to fix it by either welding or brazing. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a resonance type scanner that can be driven in a small size, high speed, large amplitude, and low power consumption.

[0005]

In order to solve the above-mentioned problems, as shown in FIG. 2, the holder 2 is made of thin light metal, two holes are formed on both sides, and the resonance spring 1 is passed through the holes at right angles. Form a bending vibration axis. The drive permanent magnet 3 and the optical scanning mirror 4 are bonded onto the holder 2 to form a vibrating section. By applying an appropriate tension in the axial direction of the resonance spring when the vibrating portion is attached to the scanner body, the resonance spring and the holder 2 of the vibrating portion are securely fixed without any means such as bonding or welding. To be done.

Further, according to the second aspect of the present invention, since the scanning mirror is adhered to the driving permanent magnet, even if the strength of the mirror itself is small, it is not deformed by acceleration due to vibration, and a thin and light mirror can be adopted, so that the vibrating portion is provided. The weight can be reduced, and thus a higher resonance frequency can be obtained. By designing each component so that the vibrating portion has a three-dimensional center of gravity with respect to the central axis of the resonance spring 1, it is possible to obtain a stable resonance type scanner that suppresses unnecessary vibration.

[0007]

The driving permanent magnet 3 of the vibrating portion according to claim 1 is magnetized as N and S in the direction perpendicular to the vibration axis formed by the resonance spring 1 as shown in FIG. When the drive coil 5 of the magnetic field generator disposed at a predetermined distance below the vibrating section is energized, the magnetic flux of the same polarity passes through the drive permanent magnet 3, so that it is attracted to both sides of the vibrating shaft. The force and the repulsive force work, and the vibrating portion including the optical scanning mirror 4 is angularly displaced about the vibration axis. When an AC voltage that is the same as or very close to the resonance frequency of the vibrating section is applied to the drive coil 5,
The above-mentioned angular displacements occur alternately and the vibrating part becomes in resonance,
A large angular displacement can be obtained with a relatively small driving power.

The stress applied to the resonance spring due to the angular displacement is smaller as the wire diameter is smaller and the length of the resonance spring is longer if the deflection angle is constant. Therefore, for miniaturization, it is appropriate to use a resonance spring having a small wire diameter. Further, the thinner the resonance spring, the smaller the driving force is, so that the driving permanent magnet 3 can be downsized and the weight of the vibrating portion can be reduced. As a result, a small-sized and high-speed resonant scanner can be realized. Further, by applying an appropriate tension to the resonance spring 1, not only the resonance spring 1 and the vibrating portion are securely fixed, but also a stable vibration axis without vibration is formed.

According to the second aspect of the present invention, since the mirror 4 having a reflective layer formed on the surface of the glass is adhered to the driving permanent magnet 3, deformation of the mirror due to acceleration of vibration can be prevented. Can be used, the weight of the vibrating portion can be reduced, and the moment of inertia about the vibrating axis is also reduced, so that a higher resonance frequency can be obtained.

[0010]

Embodiments of the present invention will be described with reference to FIGS. The vibrating part shown in FIG. 1 has a drive permanent magnet 3 bonded on a holder 2 made of a light metal such as duralumin, and a surface mirror made of thin glass is bonded on the other surface of the drive permanent magnet 3. It was done. Resonance spring 1
Penetrates through holes provided at both ends of the holder 2 and is molded as seen in FIGS. This vibrating part is fixed to the frame 6 of the scanner body as seen in FIG. At this time, a constant tension is applied to the resonance spring 1 in the axial direction. Due to this tension, the vibrating axis becomes an ideal straight line, and the vibrating section is in a state in which stable angular displacement can be performed with the resonance spring 1 as the axis. Drive coil 5
By passing an alternating current having a resonance frequency or a frequency close to that of the vibrating portion, an attractive force / repulsive force is exerted on both ends of the driving permanent magnet 3, and the vibrating portion is brought into a resonance state to obtain a large angular displacement with a small electric power. . When laser light is incident on the scanning mirror, the laser light can be scanned by the angular displacement of the scanning mirror. In the embodiment shown in FIG. 3, a driving permanent magnet 3 and an optical scanning mirror 4 are adhered to both surfaces of a holder 2, respectively, and the resonance spring 1 functions to hold the driving permanent magnet. The permanent magnet 3 has an effect of preventing peeling.

[0011]

According to the first aspect of the present invention, the vibrating portion including the optical scanning mirror 4, the driving permanent magnet 3 and the holder 2 and the resonance spring 1 can be fixed without any means such as welding or adhesion. It withstands the large acceleration that occurs when vibrating at a high resonance frequency. According to the result of the trial production, it is 1KHz despite the small size of 1/5 to 1/10 in volume ratio as compared with the conventional product of 15 × 20 × 13 mm.
It was possible to obtain a semi-permanent life of 10 ¹¹ times or more with a high frequency of ± 10 ° or more and a large amplitude.

[0012]

[Brief description of the drawings]

FIG. 1 is a perspective view showing a first embodiment of the present invention.

FIG. 2 is a side view showing the first embodiment of the present invention.

FIG. 3 is a side view showing a second embodiment of the present invention.

FIG. 4 is a side view showing a resonance type scanner using the first embodiment of the present invention.

FIG. 5 is a perspective view showing a conventional example.

[Explanation of symbols]

 1, 21, 31 Resonance spring 2, 22, 32 Holder 3 Driving permanent magnet 4 Optical scanning mirror 5 Driving coil 6 Frame

Claims (2)

[Claims] 1. A vibrating section consisting of an optical scanning mirror, a driving permanent magnet, and a holder for holding them in the center of a torsion spring (hereinafter referred to as a resonance spring) formed by a piano wire or the like having both ends fixed to a frame. In a resonance-type scanner that is fixed and causes the vibration frequency to vibrate by causing an alternating current near or to the resonance frequency of the vibration frequency to flow in the driving coil, and to scan light, the two holes formed in the vibration frequency , Bending through the resonance spring in the vibration axis direction,
A resonance type scanner characterized in that a resonance spring and a vibrating portion are fixed by applying a constant tension in an axial direction. 2. A resonance type scanner having means for adhering an optical scanning mirror to a driving plate permanent magnet to enhance the rigidity of the mirror.