JP4910668B2 - Optical device, optical scanner, and image forming apparatus - Google Patents

Description

  The present invention relates to an optical device, an optical scanner, and an image forming apparatus.

  As an optical device that deflects and scans light reflected by a light reflecting portion having light reflectivity, for example, an optical scanner used in a laser printer or the like is known. As such an optical scanner, a scanner using a structure having a torsional vibrator manufactured by processing a Si substrate by a micromachining technique has been proposed. An optical scanner using such a structure has an advantage that optical scanning can be performed at a higher speed than a polygon mirror.

For example, the optical scanner according to Patent Document 1 supports both ends of a plate-like reflection mirror with a pair of spring portions, and each spring portion branches into two in the middle and is driven on each branch portion. A source piezoelectric body is provided. In such an actuator, by applying a voltage to each piezoelectric body, the pair of branch portions are bent and deformed in opposite directions by each spring portion, and the reflection mirror is rotated while the entire spring portion is twisted. Move.
In such an optical scanner, since the expansion and contraction direction of each piezoelectric body is parallel to the surface of the reflection mirror, the size of the optical scanner is prevented from increasing in the thickness direction of the reflection mirror, and The amount of body displacement can be increased. As a result, it is possible to increase the rotation angle of the reflection mirror while reducing the size of the optical scanner.

  However, since the optical scanner according to Patent Document 1 is provided with a piezoelectric body at each branch portion of each spring portion, a total of four piezoelectric bodies are required, resulting in an increase in cost. In addition, when the number of piezoelectric bodies is large as described above, there is a problem that it is difficult to smoothly rotate the reflecting mirror because it is easily affected by a displacement of the mounting positions of each piezoelectric body or a dimensional error. In order to avoid this problem, if the mounting accuracy and dimensional accuracy of the piezoelectric body are increased, the cost is further increased.

JP 2004-191953 A

  An object of the present invention is to provide an optical device, an optical scanner, and an image forming apparatus capable of smoothly rotating a movable plate with a large swing angle while reducing cost and size.

Such an object is achieved by the present invention described below.
The optical device of the present invention includes a support member,
A movable plate provided with a light reflecting portion having light reflectivity;
A pair of shaft members rotatably supporting the movable plate with respect to the support member;
Drive means for applying a torsional moment to each shaft member;
An optical device configured to deflect or scan the light reflected by the light reflecting portion by rotating the movable plate while twisting and deforming each shaft member by the operation of the driving means,
The drive means has a longitudinal shape that is parallel to the plate surface of the movable plate and extends in a direction substantially perpendicular to the rotation center axis of the movable plate, and the rotation center axis is positioned in the vicinity of one end thereof. A pair of drive members that support the shaft members, and a longitudinal shape extending in a direction parallel to the rotation center axis, one end of which is fixed to the support member and the other end of the drive A pair of elastically deformable first deformable members connected to the one end of the member and a longitudinal shape, one end of which is fixed to the support member, and the other end is the one end of the drive member A pair of elastically deformable second deformable members connected to the other end opposite to each other, and joined on the second deformable members, and extend and contract in the longitudinal direction of the second deformable members A pair of piezoelectric elements, and by expanding and contracting each piezoelectric element by energization, The second deformable member is bent and deformed, and the drive member is rotated while twisting and deforming each first deformable member to give a torsional moment to each shaft member, and the movable plate It is comprised so that may be rotated.

Accordingly, it is possible to turn the movable plate by applying a torsional moment to each shaft member with one piezoelectric element while suppressing the shake of the rotation central axis of the movable plate.
In particular, since the rotation center axis of the movable plate is located in the vicinity of one end portion of each drive member that is torsionally deformed, the drive force is applied only to one side (the other end portion) of the drive member with respect to the rotation center axis of the movable plate. Even if this is applied, it is possible to prevent blurring of the rotation center axis of the movable plate. Therefore, the number of piezoelectric elements required for rotating the movable plate of the piezoelectric element can be reduced, so that the cost of the optical device can be reduced. In addition, when the number of piezoelectric elements is small as described above, it is difficult to be affected by a displacement of a mounting position of each piezoelectric element or a dimensional error, and it is easy to smoothly rotate the movable plate.

Further, when each drive member is rotated, each first deformation member is torsionally deformed (mainly torsional deformation) and each second drive member is bent to deform (mainly bending deformation). However, it is possible to prevent blurring of the rotation center axis of the movable plate.
Further, since the expansion / contraction direction of the piezoelectric element is parallel to the plate surface of the movable plate, the displacement of the piezoelectric element is increased while preventing the size of the optical device from increasing in the thickness direction of the movable plate. be able to. As a result, the rotation angle of the movable plate can be increased while reducing the size of the optical device.

In the optical device according to the aspect of the invention, it is preferable that each of the first deformation members is provided in the vicinity of the rotation center axis.
Thereby, it is possible to suppress the shake of the rotation center axis of the movable plate while simplifying the shape of the pair of shaft members.
In the optical device according to the aspect of the invention, it is preferable that each of the first deformable members is provided on the rotation center axis.
Accordingly, it is possible to further suppress the blurring of the rotation center axis of the movable plate while simplifying the shape of the pair of shaft members.

In the optical device of the present invention, when the movable plate is viewed in plan, the pair of drive members, the pair of first deformable members, the pair of second deformable members, and the pair of piezoelectric elements Is preferably provided so that the arrangement thereof is substantially symmetric with respect to a line segment passing through the center of the movable plate in a direction perpendicular to the rotation center axis.
As a result, it is possible to further suppress blurring of the rotation center axis of the movable plate while simplifying the mounting position and driving of the piezoelectric element.

In the optical device according to the aspect of the invention, it is preferable that each of the second deformable members extends in a direction substantially perpendicular to the rotation center axis.
Thereby, the rotation of the drive member can be made smoother, and blurring of the rotation center axis of the movable plate can be prevented.
In the optical device according to the aspect of the invention, each of the second deformable members extends in a direction substantially parallel to the rotation center axis, and each of the second deformable members corresponds to the corresponding drive member. On the other hand, it is preferably located on the side opposite to the movable plate.
As a result, the second deforming member is deformed while tension is applied to the pair of shaft members, so that it is possible to further suppress the blurring of the rotation center axis of the movable plate.

In the optical device according to the aspect of the invention, each of the second deformable members extends in a direction substantially parallel to the rotation center axis, and each of the first deformable members and each of the second deformable members is It is preferable that each of the corresponding driving members is located on the movable plate side.
Thereby, the dimension of the optical device in the rotation center axis direction of the movable plate can be suppressed.

In the optical device according to the aspect of the invention, the driving unit applies a voltage that periodically changes at a frequency equal to a torsional resonance frequency of a torsional vibrator formed of the movable plate and the pair of shaft members to each piezoelectric element. It is preferable that it is comprised.
Thereby, the rotation angle of the movable plate can be increased while suppressing the deformation amount of each first deformation member and each second deformation member and the displacement amount of each piezoelectric element.

In the optical device according to the aspect of the invention, the pair of piezoelectric elements are both arranged so as to be eccentrically located on one side with respect to the rotation center axis, and the driving means is a timing of expansion / contraction of the pair of piezoelectric elements. It is preferable that a voltage is applied to the piezoelectric element so that the two are the same.
Thereby, the structure of the drive circuit which drives a piezoelectric element can be simplified.

The optical scanner of the present invention includes a movable plate having a light reflecting portion having light reflectivity,
A pair of shaft members that rotatably support the movable plate;
Drive means for applying a torsional moment to each shaft member;
An optical scanner configured to scan the light reflected by the light reflecting portion by rotating the movable plate while twisting and deforming each shaft member by the operation of the driving means;
The drive means has a longitudinal shape that is parallel to the plate surface of the movable plate and extends in a direction substantially perpendicular to the rotation center axis of the movable plate, and the rotation center axis is positioned in the vicinity of one end thereof. A pair of drive members that support the shaft members, and a longitudinal shape extending in a direction parallel to the rotation center axis, one end of which is fixed to the support member and the other end of the drive A pair of elastically deformable first deformable members connected to the one end of the member and a longitudinal shape, one end of which is fixed to the support member, and the other end is the one end of the drive member A pair of elastically deformable second deformable members connected to the other end opposite to each other, and joined on the second deformable members, and extend and contract in the longitudinal direction of the second deformable members A pair of piezoelectric elements, and by expanding and contracting each piezoelectric element by energization, The second deformable member is bent and deformed, and the drive member is rotated while twisting and deforming each first deformable member to give a torsional moment to each shaft member, and the movable plate It is comprised so that may be rotated.
Accordingly, it is possible to provide an optical scanner capable of smoothly rotating the movable plate with a large swing angle while achieving cost reduction and downsizing.

An image forming apparatus of the present invention includes a movable plate having a light reflecting portion having light reflectivity,
A pair of shaft members that rotatably support the movable plate;
Drive means for applying a torsional moment to each shaft member;
With the operation of the driving means, the movable plate is rotated while twisting and deforming each shaft member, and the light reflected by the light reflecting portion is subjected to main scanning and / or sub scanning, and an image is formed on the object. An image forming apparatus configured to form
The drive means has a longitudinal shape that is parallel to the plate surface of the movable plate and extends in a direction substantially perpendicular to the rotation center axis of the movable plate, and the rotation center axis is positioned in the vicinity of one end thereof. A pair of drive members that support the shaft members, and a longitudinal shape extending in a direction parallel to the rotation center axis, one end of which is fixed to the support member and the other end of the drive A pair of elastically deformable first deformable members connected to the one end of the member and a longitudinal shape, one end of which is fixed to the support member, and the other end is the one end of the drive member A pair of elastically deformable second deformable members connected to the other end opposite to each other, and joined on the second deformable members, and extend and contract in the longitudinal direction of the second deformable members A pair of piezoelectric elements, and by expanding and contracting each piezoelectric element by energization, The second deformable member is bent and deformed, and the drive member is rotated while twisting and deforming each first deformable member to give a torsional moment to each shaft member, and the movable plate It is comprised so that may be rotated.
As a result, the movable plate can be smoothly driven with a large deflection angle while reducing costs and downsizing. Therefore, the image forming apparatus of the present invention can obtain an excellent image while reducing the size and cost.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of an optical device, an optical scanner, and an image forming apparatus of the invention will be described with reference to the accompanying drawings.
<First Embodiment>
First, a first embodiment of the present invention will be described.
1 is a perspective view showing a first embodiment of the optical device of the present invention, FIG. 2 is a plan view of the optical device shown in FIG. 1, FIG. 3 is a cross-sectional view taken along line AA in FIG. FIG. 2 is a diagram for explaining the operation of the optical device shown in FIG. 1. In the following, for convenience of explanation, the front side of the page in FIG. 2 is referred to as “up”, the back side of the page is referred to as “down”, the right side is referred to as “right”, and the left side is referred to as “left”. The upper side is called “upper”, the lower side is called “lower”, the right side is called “right”, and the left side is called “left”.

As shown in FIGS. 1 to 3, the optical device 1 includes a base 2 having a vibration system, piezoelectric elements 31 and 32 for driving the vibration system of the base 2, and a support 4 that supports the base 2. have. The base body 2 and the support body 4 may be integrally formed, or the support body 4 can be omitted.
In the optical device 1, the piezoelectric elements 31 and 32 are expanded and contracted by energization to generate vibration (rotation) around the rotation center axis X in the vibration system of the base 2.

Hereinafter, each part which comprises the optical device 1 is demonstrated sequentially.
As shown in FIG. 1 and FIG. 2, the base body 2 having the vibration system includes a frame-shaped support member 21, a movable plate 22 provided inside the support member 21, and the movable plate 22 as a rotation center axis. A pair of shaft members 23 and 24 that are supported rotatably around X, a pair of drive members 25 and 26 coupled to the pair of shaft members 23 and 24, respectively, and a pair of drive members And a pair of first deformable members 27 and 28 and a pair of second deformable members 29 and 30 that are connected to correspond to 25 and 26, respectively. In the present embodiment, the base 2 is formed so as to have a symmetrical shape when viewed in plan.

The support member 21 has a frame shape (more specifically, a quadrangular ring shape).
A movable plate 22 is provided inside the support member 21 while being separated from the support member 21.
The movable plate 22 has a plate shape, and a light reflecting portion 221 is provided on the plate surface (upper surface). Thereby, the optical device 1 can be applied to optical devices such as an optical scanner, an optical attenuator, and an optical switch.

In this embodiment, the planar view shape of the movable plate 22 is a circle. That is, the movable plate 22 has a disk shape. Therefore, it is possible to increase the area available for light reflection of the light reflecting portion 221 while suppressing the moment of inertia of the movable plate 22. The planar view shape of the movable plate 22 is determined according to the design of the optical device and the like, and is not limited to the disk shape as described above. For example, a polygonal shape such as a quadrilateral, a pentagon, Alternatively, it may be oval or oval.
Such a movable plate 22 is supported by a pair of shaft members 23 and 24 provided along the rotation center axis X.

Each of the shaft members 23 and 24 has a longitudinal shape along the rotation center axis X and can be twisted and deformed around the rotation center axis X.
Such a shaft member 23 has one end (right end) in the longitudinal direction connected to the movable plate 22 and the other end (left end) connected to the drive member 25. Similarly, the shaft member 24 has one end (left end) in the longitudinal direction connected to the movable plate 22 and the other end connected to the drive member 26.

In other words, the movable plate 22 is supported by the drive member 25 via the shaft member 23 and is also supported by the drive member 26 via the shaft member 24.
Each of the drive members 25 and 26 has a longitudinal shape extending in a direction parallel to the plate surface of the movable plate 22 and perpendicular to the rotation center axis X.
The drive member 25 supports the shaft member 23 described above at a portion (hereinafter referred to as one end portion 251) on the one end 251 (fixed portion) side. Similarly, the drive member 26 supports the shaft member 24 at a portion (hereinafter referred to as one end portion 261) on one end (fixed portion) 261 side. That is, the one end 251 of the drive member 25 and the one end 261 of the drive member 26 are respectively positioned on the rotation center axis X of the movable plate 22.
Thus, the drive member 25 is connected to the shaft member 23 so as to position the rotation center axis X in the vicinity of the one end 251 thereof. Similarly, the drive member 26 is coupled to the shaft member 24 so that the rotation center axis X is positioned in the vicinity of the one end 261 thereof.

Each of the first deformable members 27 and 28 is configured to be mainly twisted and deformed, and has a longitudinal shape extending in a direction substantially parallel to the rotation center axis X.
The first deformation member 27 has one end 271 fixed to the support member 21, a portion on the other end 272 side (hereinafter referred to as the other end 272) connected to the one end 251 of the drive member 25, It is configured to be elastically deformable. Similarly, one end 281 of the first deformation member 28 is fixed to the support member 21, and a portion on the other end 282 side (hereinafter referred to as the other end portion 282) is connected to the one end portion 261 of the drive member 26. It is connected and configured to be elastically deformable.
In particular, in the present embodiment, the first deformation members 27 and 28 are located on the opposite side (that is, the outside) of the movable plate 22 with respect to the corresponding drive members 25 and 26, respectively.

On the other hand, each of the second deformable members 29 and 30 is mainly configured to bend and deform, and has a longitudinal shape extending in a direction substantially parallel to the rotation center axis X.
The second deformable member 29 has one end 291 fixed to the support member 21 and the other end 292 side portion (hereinafter referred to as the other end 292) opposite to the one end 251 of the drive member 25. The other end portion 252 is connected to be elastically deformable. Similarly, one end 301 of the second deformable member 30 is fixed to the support member 21, and a portion on the other end 302 side (hereinafter referred to as the other end portion 302) is connected to the one end portion 261 of the drive member 26. Is connected to the other end 262 on the opposite side, and is configured to be elastically deformable.
In particular, in the present embodiment, the first deformation members 27 and 28 are located on the opposite side (that is, the outside) of the movable plate 22 with respect to the corresponding drive members 25 and 26, respectively. As a result, the second deformable members 29 and 30 are deformed while applying tension to the pair of shaft members 23 and 24, so that it is possible to further suppress the shake of the rotation center axis X of the movable plate 22.

  A piezoelectric element 31 that expands and contracts in the longitudinal direction (extending direction) is bonded onto the second deforming member 29 and expands and contracts in the longitudinal direction (extending direction) on the second deforming member 30. The piezoelectric element 32 is joined. As a result, the second deformable members 29 and 30 are bent and deformed, and accordingly, the drive members 25 and 26 are rotated while the first deformable members 27 and 28 are twisted and deformed. By rotating the drive members 25 and 26 as described above, the movable plate 22 can be rotated while applying a torsional moment to the shaft members 23 and 24 and torsionally deforming the shaft members 23 and 24. The piezoelectric elements 31 and 32 will be described in detail later.

  The movable plate 22 and the pair of shaft members 23 and 24 constitute a first vibration system, and the pair of driving members 25 and 26 and the pair of first deformation members 27 and 28 and the pair of second members. The deformable members 29 and 30 and the pair of piezoelectric elements 31 and 32 constitute a second vibration system, and these vibration systems constitute a two-degree-of-freedom vibration system. Therefore, even if the amplitude of the second vibration system is small, the amplitude of the first vibration system can be increased. That is, even if the displacement amount of each drive member 25, 26 and each piezoelectric element 31, 32 and the bending deformation amount of each deformation member 27, 28, 29, 30 are small, the rotation angle of the movable plate 22 can be increased. it can.

The base 2 as described above is made of, for example, silicon as a main material. The base body 2 includes a support member 21, a movable plate 22, a pair of shaft members 23, 24, a pair of drive members 25, 26, a pair of first deformation members 27, 28, and a pair of second members. The deformation members 29 and 30 are integrally formed.
In particular, in the present embodiment, the substrate 2 is formed by processing one Si layer of the SOI substrate. Further, the first layer 41 of the support 4 described later is formed by processing the other Si layer of the SOI substrate (the Si layer opposite to the one Si layer). Further, a second layer 42 of the support 4 described later is formed by processing the SiO ₂ layer of the SOI substrate.

As described above, the support member 21, the movable plate 22, the pair of shaft members 23, 24, the pair of drive members 25, 26, the pair of first deformation members 27, 28, and the pair of second deformation members. If 29 and 30 are formed by processing the Si layer of the SOI substrate, these can be formed relatively easily and with high accuracy. The support member 21, the movable plate 22, a pair of shaft members 23, 24, a pair of drive members 25, 26, a pair of deformation members 27, 28, and a pair of second deformation members 29, 30 are integrated. Since these are formed of silicon and made of silicon, excellent vibration characteristics can be exhibited.
When the base 2 and the like are manufactured using the SOI substrate in this way, a structure such as the base 2 can be formed easily and with high accuracy. Therefore, the optical device 1 having excellent characteristics can be manufactured at low cost. In addition, the board | substrate and base material used for manufacture of the base | substrate 2 grade | etc., Are not limited to the SOI substrate mentioned above.

A pair of piezoelectric elements 31 and 32 are bonded to the upper surface of the base 2 as described above.
The piezoelectric element 31 is bonded onto the second deformable member 29 and arranged so as to expand and contract in the longitudinal direction. On the other hand, the piezoelectric element 32 is bonded onto the second deformable member 30 and arranged so as to expand and contract in the longitudinal direction.
In particular, the piezoelectric element 31 has one end in the expansion / contraction direction located near the other end 252 of the drive member 25 and the other end located on the support member 21. Similarly, the piezoelectric element 32 has one end in the expansion / contraction direction located near the other end 262 of the drive member 26 and the other end located on the support member 21. Thus, since the piezoelectric elements 31 and 32 are provided over a wide range, the second deformable members 29 and 30 can be greatly bent and deformed.

Each of the piezoelectric elements 31 and 32 includes, for example, a piezoelectric layer composed mainly of a piezoelectric material such as lead zirconate titanate (PZT), and a pair of electrodes that sandwich the piezoelectric layer. It consists of One electrode of the pair of electrodes is bonded to the upper surface of the second deformable member 29 or the second deformable member 30.
Such piezoelectric elements 31 and 32 are connected to a power supply circuit (not shown) so that a periodically changing voltage is applied thereto. Thereby, the piezoelectric elements 31 and 32 can be expanded and contracted.

On the other hand, the support 4 is joined to the lower surface of the support member 21 of the base 2.
The support body 4 is joined to the lower surface of the support member 21 and has an annular shape. When the vibration system of the base body 2 vibrates, that is, when the movable plate 22 rotates (vibrates). An escape portion (space) that prevents contact with the support 4 is formed.
The support 4 includes a first layer 41 and a second layer 42 bonded to the upper surface of the first layer 41, and the upper surface of the first layer 41 is bonded to the lower surface of the support member 21. Yes. The support 4 may be composed of a single layer or three or more layers.
As described above, the first layer 41 is composed of silicon as a main material, and the second layer 42 is composed of SiO ₂ as a main material.

The optical device 1 configured as described above operates as follows. Since the optical device 1 is configured to be bilaterally symmetric as described above, in the following description, the right side portion of the optical device 1 will be described as a representative.
In the operation of the optical device 1, a periodically changing voltage is applied to the piezoelectric element 32. Such a voltage may be, for example, alternating current or intermittent direct current.

  As described above, since the pair of piezoelectric elements 31 and 32 are arranged so as to be unevenly distributed on one side with respect to the rotation center axis X, the timing of expansion / contraction of the pair of piezoelectric elements 31 and 32 is determined. A voltage is applied to each of the piezoelectric elements 31 and 32 so as to be the same as each other. Thereby, the structure of the drive circuit and power supply circuit (not shown) which drive the piezoelectric elements 31 and 32 can be simplified.

  The voltage applied to each piezoelectric element 31 and 32 is a voltage that periodically changes at a frequency equal to the torsional resonance frequency of the torsional vibrator constituted by the movable plate 22 and the pair of shaft members 23 and 24. Is preferred. As a result, the rotational angle of the movable plate 22 is reduced while suppressing the deformation amount of the first deformation members 27 and 28 and the second deformation members 29 and 30 and the displacement amounts of the drive members 25 and 26 and the piezoelectric elements 31 and 32. Can be bigger. That is, the rotation angle of the movable plate 22 can be increased while enabling low voltage driving.

The piezoelectric element 32 to which such a voltage is applied expands and contracts in the longitudinal direction. In other words, the piezoelectric element 32 alternately repeats the stretched state and the contracted state at the period of the voltage.
More specifically, when no voltage is applied, the piezoelectric element 32 is in a contracted state as shown in FIG. 4A, and each of the second deformable members 30 is bent and deformed (bends downward). The first deformation member 28 is not twisted and deformed. On the other hand, when a voltage is applied, the piezoelectric element 32 is in an expanded state as shown in FIG. 4B, and the second deformable member 30 is bent and deformed so as to bend downward. Due to the deformation of the second deformation member 30, the end portion 262 of the drive member 26 is displaced downward. At this time, since the one end 261 of the drive member 26 is supported by the first deformable member 28, the position of the one end 261 hardly changes as shown in FIG. Changes (displaces) to incline. When the piezoelectric element 32 is alternately expanded and contracted in a predetermined cycle alternately, when the voltage is not applied to the piezoelectric element 32, the torsionally deformed first deformable member 28 or the bending deformation is performed. Due to the reaction force of the second deformable member 30, the first deformable member 28 is twisted in the direction opposite to the state shown in the figure, and the second deformable member 30 is bent and deformed so as to bend upward.

When the attitude of the drive member 26 changes in this way, the attitude of the shaft member 24 in the cross section is changed in accordance with the change, and a twisting torque is applied to the shaft member 24.
With such a twisting torque, the movable plate 22 rotates while the shaft member 24 is twisted and deformed.
As described above, the drive member 26, the first deformation member 28, the second deformation member 30, and the piezoelectric element 32 give a torsional moment to the shaft member 24. Similarly, the drive member 25, the first deformation member 27, the second deformation member 29, and the piezoelectric element 31 give a torsional moment to the shaft member 23. In this way, the pair of driving members 25, 26, the pair of first deformable members 27, 28, the pair of second deformable members 29, 30 and the piezoelectric elements 31, 32 are connected to each shaft member 23. , 24 is configured to provide a torsional moment.
By operating the driving means, the movable plate 22 is rotated while twisting and deforming the shaft members 23 and 24, and the light reflected by the light reflecting portion 221 is deflected or scanned.

According to such an optical device 1, the movable plate 22 is rotated by applying a torsional moment to each of the shaft members 23, 24 with one piezoelectric element while suppressing the shake of the rotation center axis X of the movable plate 22. be able to.
In particular, since the rotation center axis X of the movable plate 22 is located in the vicinity of one end (251, 261) of each drive member 25, 26 torsionally deformed, the drive member is relative to the rotation center axis X of the movable plate 22. Even if a driving force is applied only to one side of 25 and 26 (the portion opposite to the fixed portion), the movement of the rotation center axis X of the movable plate 22 can be prevented. Therefore, the number of piezoelectric elements required for the rotation of the movable plate 22 of the piezoelectric elements 31 and 32 is small (in this embodiment, two), so that the cost of the optical device 1 can be reduced. In addition, when the number of piezoelectric elements is small as described above, the movable plate 22 can be easily rotated smoothly without being affected by the displacement of the mounting position of each piezoelectric element and the dimensional error.

Further, when the drive members 25 and 26 are rotated, the first deformation members 27 and 28 are torsionally deformed (mainly torsional deformation), and the second deformation members 29 and 30 are bendably deformed (bending deformation). Therefore, also in this respect, it is possible to prevent blurring of the rotation center axis X of the movable plate 22.
Further, since the first deforming members 27 and 28 are provided in the vicinity of the rotation center axis X, the rotation center axis of the movable plate 22 is simplified while simplifying the shape of the pair of shaft members 23 and 24. X blurring can be suppressed.

  Further, since the expansion / contraction direction of the piezoelectric elements 31 and 32 is a direction parallel to the plate surface of the movable plate 22, the piezoelectric element 31 is prevented from increasing the dimension of the optical device 1 in the thickness direction of the movable plate 22. , 32 can be increased. As a result, the rotation angle of the movable plate 22 can be increased while reducing the size of the optical device 1. In addition, since the expansion and contraction directions of the piezoelectric elements 31 and 32 are parallel to the rotation center axis X of the movable plate 22, the dimensions of the optical device 1 in the direction perpendicular to the rotation center axis X can also be suppressed. .

Further, when the movable plate 22 is viewed in plan, the pair of driving members 25 and 26, the pair of first deformation members 27 and 28, the pair of second deformation members 29 and 30, and the piezoelectric elements 31 and 32. Is arranged so that the arrangement thereof is substantially symmetric with respect to a line segment passing through the center of the movable plate 22 in a direction perpendicular to the rotation center axis X, so that the piezoelectric elements 31 and 32 are attached. While simplifying the position and driving, it is possible to further suppress blurring of the rotation center axis X of the movable plate 22.
As described above, according to the optical device 1, the movable plate 22 can be smoothly rotated with a large swing angle while achieving cost reduction and downsizing.

Second Embodiment
Next, a second embodiment of the optical device of the present invention will be described.
FIG. 5 is a plan view showing a second embodiment of the optical device of the present invention. In the following, for convenience of explanation, the front side with respect to the paper surface in FIG. 5 is referred to as “up”, the back side with respect to the paper surface is referred to as “down”, the right side is referred to as “right”, and the left side is referred to as “left”.
Hereinafter, the optical device of the second embodiment will be described focusing on the differences from the optical device of the first embodiment described above, and the description of the same matters will be omitted.
The optical device 1A of the second embodiment is substantially the same as the optical device 1 of the first embodiment except that the length of the driving member and the arrangement of the first deformation member are different.

An optical device 1A shown in FIG. 5 includes a base 2A having a vibration system. Although not shown, a frame-like support is bonded to the lower surface of the base 2A, and the support is a vibration system of the base 2A. The base 2A is supported from below while allowing the above vibrations to be allowed.
The base body 2A includes a pair of drive members 25A and 26A coupled corresponding to the shaft members 23 and 24, and a pair of first members coupled corresponding to the pair of drive members 25A and 26A, respectively. Deformation members 27A and 28A are provided.
In such an optical device 1A, the drive members 25A and 26A are rotated while the first deformation members 27A and 28A are twisted and deformed by the bending deformation of the second deformation members 29 and 30. By such rotation of the drive members 25A and 26A, the shaft members 23 and 24 are given a torsional moment.

Each drive member 25A, 26A has a longitudinal shape extending in a direction parallel to the plate surface of the movable plate 22 and perpendicular to the rotation center axis X.
The drive member 25A supports the above-described shaft member 23 at a portion on one end 251A (fixed portion) side (hereinafter referred to as one end portion 251A), and a second deformation is formed on the end portion on the other end 252A side. The member 29 is connected. Similarly, the drive member 26A supports the shaft member 24 at a portion on one end (fixed portion) 261A side (hereinafter referred to as one end portion 261A), and a second end on the other end 262A side. The deformation member 30 is connected.

Each of the first deformable members 27A and 28A is mainly configured to be torsionally deformed, and has a longitudinal shape extending in a direction substantially parallel to the rotation center axis X.
The first deformation member 27A has one end 271A fixed to the support member 21, and the other end 272A side portion (hereinafter referred to as the other end 272A) is connected to the one end 251A of the drive member 25A. It is configured to be elastically deformable. Similarly, one end 281A of the first deformation member 28A is fixed to the support member 21, and a portion on the other end 282A side (hereinafter referred to as the other end 282A) is connected to one end 261A of the drive member 26A. It is connected and configured to be elastically deformable.

In particular, in the present embodiment, the first deformation members 27A and 28A are provided on the rotation center axis X. Thereby, it is possible to further suppress the shake of the rotation center axis X of the movable plate 22 while simplifying the shape of the pair of shaft members 23 and 24.
According to the optical device 1A described above, in addition to the same effects as the optical device 1 of the first embodiment described above, the movable plate 22 can be rotated more smoothly.

<Third Embodiment>
Next, a third embodiment of the optical device of the present invention will be described.
FIG. 6 is a plan view showing a third embodiment of the optical device of the present invention. In the following, for convenience of explanation, the front side with respect to the paper surface in FIG. 6 is referred to as “upper”, the rear side with respect to the paper surface is referred to as “lower”, the right side is referred to as “right”, and the left side is referred to as “left”.
Hereinafter, the optical device of the third embodiment will be described focusing on the differences from the optical device of the first embodiment described above, and the description of the same matters will be omitted.
The optical device 1B of the third embodiment is substantially the same as the optical device 1 of the first embodiment except that the arrangement of the second deformation member and the piezoelectric element is different.

An optical device 1B shown in FIG. 6 has a base 2B having a vibration system. Although not shown, a frame-like support is bonded to the lower surface of the base 2B, and the support is a vibration system of the base 2B. The base 2B is supported from the lower side while allowing the vibrations.
The base body 2B includes a pair of second deformation members 29B and 30B provided corresponding to the pair of driving members 25 and 26, respectively, and a pair of piezoelectric elements 31B and 32B provided corresponding thereto. And have.
In such an optical device 1B, the drive members 25 and 26 are rotated while the first deformation members 27 and 28 are twisted and deformed by the bending deformation of the second deformation members 29B and 30B. By such rotation of the drive members 25 and 26, the shaft members 23 and 24 are given a torsional moment.

Each of the second deformable members 29B and 30B has a longitudinal shape extending in a direction substantially perpendicular to the rotation center axis X.
The second deformation member 29B has one end 291B fixed to the support member 21 and the other end 292B connected to the other end 252 of the drive member 25 so as to be elastically deformable. Similarly, the second deformation member 30B has one end 301B fixed to the support member 21 and the other end 302B connected to the other end 262 of the drive member 26 so as to be elastically deformable.

In particular, in the present embodiment, each of the second deformation members 29B and 30B extends in a direction substantially perpendicular to the rotation center axis X. Thereby, the driving members 25 and 26 can be rotated more smoothly, and the rotation of the rotation center axis X of the movable plate 22 can be prevented.
According to the optical device 1A described above, in addition to the same effects as those of the optical device 1 of the first embodiment described above, the drive members 25 and 26 can be rotated more smoothly, and the movable plate 22 can be rotated. The rotation of the rotation center axis X can be prevented.

<Fourth embodiment>
Next, a fourth embodiment of the optical device of the present invention will be described.
FIG. 7 is a plan view showing a fourth embodiment of the optical device of the present invention. In the following, for convenience of explanation, the front side with respect to the paper surface in FIG. 7 is referred to as “up”, the back side with respect to the paper surface is referred to as “down”, the right side is referred to as “right”, and the left side is referred to as “left”.
Hereinafter, the optical device according to the fourth embodiment will be described with a focus on differences from the optical device according to the first embodiment described above, and description of similar matters will be omitted.
The optical device 1C according to the fourth embodiment is substantially the same as the optical device 1 according to the first embodiment, except that the first deformation member, the second deformation member, and the piezoelectric element are different in arrangement.

An optical device 1C shown in FIG. 7 includes a base 2C having a vibration system. Although not shown, a frame-like support is bonded to the lower surface of the base 2C, and the support is a vibration system of the base 2C. The base 2C is supported from the lower side while allowing vibrations of the above.
The base body 2C includes a pair of first deformation members 27C and 28C and a pair of second deformation members 29C and 30C provided corresponding to the pair of drive members 25 and 26, respectively, and a second deformation. It has a pair of piezoelectric elements 31C and 32C provided corresponding to the members 29C and 30C, respectively.
In such an optical device 1C, the second deformable members 29C and 30C are bent and deformed by driving the piezoelectric elements 31C and 32C, and the first deformable members 27C and 28C are twisted and deformed accordingly. Then, the drive members 25 and 26 are rotated. By such rotation of the drive members 25 and 26, the shaft members 23 and 24 are given a torsional moment.

Each of the first deformation members 27C and 28C is mainly configured to be twisted and deformed, and has a longitudinal shape extending in a direction substantially parallel to the rotation center axis X.
The first deformation member 27C has one end 271C fixed to the support member 21C, the other end 272C side portion (hereinafter referred to as the other end 272C) connected to the one end 251 of the drive member 25, It is configured to be elastically deformable. Similarly, one end 281C of the first deformation member 28C is fixed to the support member 21, and a portion on the other end 282C side (hereinafter referred to as the other end portion 282C) is formed on the one end portion 261 of the drive member 26. It is connected and configured to be elastically deformable.

On the other hand, each of the second deformable members 29C, 30C is mainly configured to be torsionally deformed, and has a longitudinal shape extending in a direction substantially parallel to the rotation center axis X.
The second deformation member 29 </ b> C has one end 291 </ b> C fixed to the support member 21 </ b> C, and a portion on the other end 292 </ b> C side (hereinafter referred to as the other end 292 </ b> C) connected to the other end 252 of the drive member 25. It is configured to be elastically deformable. Similarly, one end 301C of the second deformable member 30C is fixed to the support member 21C, and the other end 302C side portion (hereinafter referred to as the other end 302C) is the other end 262 of the drive member 26. And is configured to be elastically deformable.
The first deformation members 27C and 28C and the second deformation members 29C and 30C are positioned on the movable plate 22 side (that is, inside) with respect to the corresponding drive members 25 and 26, respectively. Thereby, the dimension of the optical device 1 in the rotation center axis direction X of the movable plate 22 can be suppressed.

The piezoelectric element 31C is bonded onto the second deformable member 29C and disposed so as to expand and contract in the longitudinal direction. On the other hand, the piezoelectric element 32C is bonded onto the second deformable member 30C and arranged to expand and contract in the longitudinal direction.
According to the optical device 1A described above, in addition to the same effects as those of the optical device 1 of the first embodiment described above, the dimensions of the optical device 1 in the rotation center axis direction X of the movable plate 22 can be suppressed. .

The optical devices 1 to 1C as described above can be applied to, for example, an optical scanner, an optical switch, an optical attenuator, and the like.
When the optical device 1 is used as an optical scanner, the optical device 1 (the optical scanner according to the present invention) scans the light reflected by the light reflecting unit 221.
Such an optical scanner can be suitably applied to an image forming apparatus such as a laser printer, an imaging display, a barcode reader, or a scanning confocal microscope. In this case, the light reflected by the light reflecting portion 221 is subjected to main scanning and / or sub scanning to form an image on the object. The image forming apparatus provided with the optical scanner of the present invention, that is, the image forming apparatus of the present invention can obtain an excellent image while reducing the size and cost.

Hereinafter, a specific example of an image forming apparatus provided with the optical scanner of the present invention will be described.
First, an example in which the present invention is applied to a printer that employs an electrophotographic system will be described.
FIG. 8 is a schematic cross-sectional view of an overall configuration showing an example of an image forming apparatus (printer) including the optical scanner of the present invention, and FIG. 9 is a schematic configuration of an exposure unit provided in the image forming apparatus shown in FIG. FIG.

  An image forming apparatus 110 (printer) shown in FIG. 8 records an image made of toner on a recording medium such as paper or an OHP sheet by a series of image forming processes including exposure, development, transfer, and fixing. As shown in FIG. 8, such an image forming apparatus 110 has a photoconductor 111 that rotates in the direction of the arrow shown in the figure, and sequentially, along the rotation direction, a charging unit 112, an exposure unit 113, a developing unit 114, and a transfer unit. A unit 115 and a cleaning unit 116 are provided. In FIG. 8, the image forming apparatus 110 is provided with a paper feed tray 117 that accommodates a recording medium P such as paper at the bottom, and a fixing device 118 at the top.

In such an image forming apparatus 110, first, in response to a command from a host computer (not shown), the photosensitive member 111, the developing roller (not shown) provided in the developing unit 114, and the intermediate transfer belt 151 rotate. Start. The photosensitive member 111 is sequentially charged by the charging unit 112 while rotating.
The charged region of the photoconductor 111 reaches an exposure position as the photoconductor 111 rotates, and a latent image corresponding to image information of the first color, for example, yellow Y, is formed in the region by the exposure unit 113. .

  The latent image formed on the photoconductor 111 reaches the development position as the photoconductor 111 rotates, and is developed with yellow toner by the developing device 144 for yellow development. As a result, a yellow toner image is formed on the photoreceptor 111. At this time, in the developing unit 114, the developing device 144 selectively faces the photoconductor 111 at the developing position. This selection is performed by changing the respective positions while maintaining the relative positional relationship of the developing devices 141 to 144 by the rotation of the holding body 145 around the axis 146.

  The yellow toner image formed on the photoconductor 111 reaches a primary transfer position (that is, a portion where the photoconductor 111 and the primary transfer roller 152 face each other) as the photoconductor 111 rotates, and is intermediated by the primary transfer roller 152. Transfer (primary transfer) is performed on the transfer belt 151. At this time, a primary transfer voltage (primary transfer bias) having a polarity opposite to the charging polarity of the toner is applied to the primary transfer roller 152. During this time, the secondary transfer roller 155 is separated from the intermediate transfer belt 151.

The same processing as described above is repeatedly executed for the second color, the third color, and the fourth color, so that the toner images of the respective colors corresponding to the respective image signals are transferred onto the intermediate transfer belt 151 in an overlapping manner. The As a result, a full color toner image is formed on the intermediate transfer belt 151.
On the other hand, the recording medium P is conveyed from the paper feed tray 117 to the secondary transfer position (that is, the portion where the secondary transfer roller 155 and the driving roller 154 face each other) by the paper feed roller 171 and the registration roller 172.

The full color toner image formed on the intermediate transfer belt 151 reaches the secondary transfer position as the intermediate transfer belt 151 rotates, and is transferred (secondary transfer) to the recording medium P by the secondary transfer roller 155. At this time, the secondary transfer roller 155 is pressed against the intermediate transfer belt 151 and a secondary transfer voltage (secondary transfer bias) is applied. Further, the intermediate transfer belt 151 rotates while the driving roller 154 is rotated and the primary transfer roller 152 and the driven roller 153 are driven to rotate.
The full-color toner image transferred to the recording medium P is heated and pressurized by the fixing device 118 and fused to the recording medium P. Thereafter, in the case of single-sided printing, the recording medium P is discharged to the outside of the image forming apparatus 110 by the discharge roller pair 173.
On the other hand, after the primary transfer position has elapsed, the toner adhering to the surface of the photoconductor 111 is scraped off by the cleaning blade 161 of the cleaning unit 116 to prepare for charging to form the next latent image. The toner scraped off is collected by a residual toner collecting unit in the cleaning unit 116.

  In the case of double-sided printing, after the recording medium P fixed on one surface by the fixing device 118 is once sandwiched by the paper discharge roller pair 173, the paper discharge roller pair 173 is driven in reverse and the conveyance roller pair 174, 176 is driven, the recording medium P is turned upside down through the transport path 175 and returned to the secondary transfer position, and an image is formed on the other surface of the recording medium P by the same operation as described above.

The exposure unit 113 provided in such an image forming apparatus receives image information from a host computer such as a personal computer (not shown) and selectively applies a laser on the uniformly charged photoreceptor 111 in accordance with the image information. It is an apparatus that forms an electrostatic latent image by irradiation.
More specifically, as shown in FIG. 9, the exposure unit 113 includes the optical device 1 that is an optical scanner, a laser light source 131, a collimator lens 132, and an fθ lens 133.

In the exposure unit 113, the laser light L is irradiated from the laser light source 131 to the optical device 1 (light reflection unit 221) via the collimator lens 132. Then, the laser beam L reflected by the light reflecting portion 221 is irradiated onto the photosensitive member 111 through the fθ lens.
At that time, the light (laser L) reflected by the light reflecting portion 221 by the driving of the optical device 1 (rotation about the rotation center axis X of the movable plate 22) scans in the axial direction of the photoconductor 111 (main scanning). ) On the other hand, the light (laser L) reflected by the light reflecting portion 221 by the rotation of the photosensitive member 111 is scanned (sub-scanned) in the circumferential direction of the photosensitive member 111. Further, the intensity of the laser light L output from the laser light source 131 changes in accordance with image information received from a host computer (not shown).
In this way, the exposure unit 113 selectively exposes the surface of the photoconductor 111 to form an image (drawing).

Next, an example in which the present invention is applied to an imaging display (display device) will be described.
FIG. 10 is a schematic view showing an example of an image forming apparatus (imaging display) of the present invention.
An image forming apparatus 119 shown in FIG. 10 includes an optical device 1 that is an optical scanner, light sources 191, 192, and 193 of three colors of R (red), G (green), and B (blue), and a cross dichroic prism (X Prism 194, galvanometer mirror 195, fixed mirror 196, and screen 197.

In such an image forming apparatus 119, light of each color is emitted from the light sources 191, 192, 193 to the optical device 1 (light reflecting unit 221) via the cross dichroic prism 194. At this time, the red light from the light source 191, the green light from the light source 192, and the blue light from the light source 193 are combined by the cross dichroic prism 194.
Then, the light (three colors of combined light) reflected by the light reflecting portion 221 is reflected by the galvanometer mirror 195, then by the fixed mirror 196, and irradiated on the screen 197.

At this time, the light reflected by the light reflecting portion 221 is scanned in the horizontal direction of the screen 197 (main scanning) by driving the optical device 1 (rotation about the rotation center axis X of the movable plate 22). On the other hand, the light reflected by the light reflecting portion 221 is scanned (sub-scanned) in the vertical direction of the screen 197 by the rotation of the galvano mirror 195 around the axis Y. In addition, the intensity of light output from the light sources 191, 192, and 193 of each color changes according to image information received from a host computer (not shown).
In this way, the image forming apparatus 119 performs image formation (drawing) on the screen 197.

While the optical device, the optical scanner, and the image forming apparatus of the present invention have been described based on the illustrated embodiment, the present invention is not limited to this. For example, in the optical device of the present invention, the configuration of each part can be replaced with any configuration that exhibits the same function, and any configuration can be added.
In the above-described embodiment, the shaft member is linear. However, the shape of the shaft member is arbitrary as long as the movable plate can be rotatably supported. For example, the shaft member may have a portion branched in the middle thereof, a wide portion or a narrow portion, or a portion that is bent. May be.

In the above-described embodiment, the piezoelectric element is bonded only to the upper surface of the substrate. However, the piezoelectric element may be bonded to the lower surface of the substrate.
In the above-described embodiment, the structure in which the optical device has a symmetrical shape has been described.
Further, in the above-described embodiment, the configuration in which the light reflecting portion is provided on the upper surface of the movable plate (the surface on the side opposite to the support) has been described, but for example, the configuration provided on the opposite surface. There may be a configuration provided on both sides.

It is a perspective view which shows 1st Embodiment of the optical device of this invention. It is a top view of the optical device shown in FIG. It is the sectional view on the AA line in FIG. It is a figure for demonstrating operation | movement of the optical device shown in FIG. It is a top view which shows 2nd Embodiment of the optical device of this invention. It is a top view which shows 3rd Embodiment of the optical device of this invention. It is a top view which shows 4th Embodiment of the optical device of this invention. 1 is a schematic cross-sectional view of an overall configuration showing an example of an image forming apparatus (printer) of the present invention. It is a figure which shows schematic structure of the exposure unit with which the image forming apparatus shown in FIG. 6 was equipped. It is the schematic which shows an example of the image forming apparatus (imaging display) of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1-1C ... Optical device 2-2C ... Base | substrate 21, 21C ... Support member 22 ... Movable plate 23, 24 ... Shaft member 25, 25A, 26, 26A ... Drive member 27, 27A, 27C, 28 28A, 28C... First deformable member 29, 29B, 29C, 30, 30B, 30C... Second deformable member 31, 31B, 31C, 32, 32B, 32C... Piezoelectric element 4. ... First layer 42... Second layer 110... Image forming apparatus 111... Photoconductor 112... Charging unit 113 .. Exposure unit 114 .. Development unit 115. ...... Feeding tray 118 ...... Fixing device 119 ...... Image forming device 131 ...... Laser light source 132 ...... Collimator lens 133 ...... fθ recording 141 to 144... Developing device 145... Holding body 146... Shaft 151... Intermediate transfer belt 152... Primary transfer roller 153. Blade 171... Feed roller 172... Registration roller 173... Discharge roller pair 174 and 176... 196... Fixed mirror 197... Screen 221... Light reflection portion 251, 261... 251A, 261A, 271, 271A, 71C, 281,281A, 281C, 291,291B, 291C, 301,301B, 301C ...... one end 252A, 262A, 292B, 302B ...... the other end P ...... recording medium

Claims (11)

A support member;
A movable plate provided with a light reflecting portion having light reflectivity;
A pair of shaft members rotatably supporting the movable plate with respect to the support member;
Drive means for applying a torsional moment to each shaft member;
An optical device configured to deflect or scan the light reflected by the light reflecting portion by rotating the movable plate while twisting and deforming each shaft member by the operation of the driving means,
The drive means has a longitudinal shape that is parallel to the plate surface of the movable plate and extends in a direction substantially perpendicular to the rotation center axis of the movable plate, and the rotation center axis is positioned in the vicinity of one end thereof. A pair of drive members that support the shaft members, and a longitudinal shape extending in a direction parallel to the rotation center axis, one end of which is fixed to the support member and the other end of the drive A pair of elastically deformable first deformable members connected to the one end of the member and a longitudinal shape, one end of which is fixed to the support member, and the other end is the one end of the drive member A pair of elastically deformable second deformable members connected to the other end opposite to each other, and joined on the second deformable members, and extend and contract in the longitudinal direction of the second deformable members A pair of piezoelectric elements, and by expanding and contracting each piezoelectric element by energization, The second deformable member is bent and deformed, and the drive member is rotated while twisting and deforming each first deformable member to give a torsional moment to each shaft member, and the movable plate An optical device characterized in that the optical device is configured to rotate.   The optical device according to claim 1, wherein each of the first deformable members is provided in the vicinity of the rotation center axis.   The optical device according to claim 2, wherein each of the first deformable members is provided on the rotation center axis.   When the movable plate is viewed in plan, the pair of driving members, the pair of first deformation members, the pair of second deformation members, and the pair of piezoelectric elements are arranged in the following manner: 4. The optical device according to claim 1, wherein the optical device is provided so as to be substantially symmetric with respect to a line segment passing through a center of the movable plate in a direction perpendicular to the rotation center axis.   5. The optical device according to claim 1, wherein each of the second deformable members extends in a direction substantially perpendicular to the rotation center axis.   Each of the second deformable members extends in a direction substantially parallel to the rotation center axis, and each of the second deformable members is opposite to the movable plate with respect to the corresponding drive member. The optical device according to claim 1, which is located on a side.   Each of the second deformation members extends in a direction substantially parallel to the rotation center axis, and each of the first deformation members and each of the second deformation members corresponds to the corresponding drive member. The optical device according to claim 1, wherein the optical device is located on the movable plate side.   The driving means is configured to apply a voltage that periodically changes at a frequency equal to a torsional resonance frequency of a torsional vibrator constituted by the movable plate and the pair of shaft members to each piezoelectric element. The optical device according to claim 1.   The pair of piezoelectric elements are both arranged so as to be unevenly distributed on one side with respect to the rotation center axis, and the driving means is configured so that the timing of expansion / contraction of the pair of piezoelectric elements is the same. The optical device according to claim 1, wherein a voltage is applied to the piezoelectric element. A support member;
A movable plate provided with a light reflecting portion having light reflectivity;
A pair of shaft members that rotatably support the movable plate;
Drive means for applying a torsional moment to each shaft member;
An optical scanner configured to scan the light reflected by the light reflecting portion by rotating the movable plate while twisting and deforming each shaft member by the operation of the driving means;
The drive means has a longitudinal shape that is parallel to the plate surface of the movable plate and extends in a direction substantially perpendicular to the rotation center axis of the movable plate, and the rotation center axis is positioned in the vicinity of one end thereof. A pair of drive members that support the shaft members, and a longitudinal shape extending in a direction parallel to the rotation center axis, one end of which is fixed to the support member and the other end of the drive A pair of elastically deformable first deformable members connected to the one end of the member and a longitudinal shape, one end of which is fixed to the support member, and the other end is the one end of the drive member A pair of elastically deformable second deformable members connected to the other end opposite to each other, and joined on the second deformable members, and extend and contract in the longitudinal direction of the second deformable members A pair of piezoelectric elements, and by expanding and contracting each piezoelectric element by energization, The second deformable member is bent and deformed, and the drive member is rotated while twisting and deforming each first deformable member to give a torsional moment to each shaft member, and the movable plate An optical scanner characterized by being configured to rotate. A support member;
A movable plate provided with a light reflecting portion having light reflectivity;
A pair of shaft members that rotatably support the movable plate;
Drive means for applying a torsional moment to each shaft member;
With the operation of the driving means, the movable plate is rotated while twisting and deforming each shaft member, and the light reflected by the light reflecting portion is subjected to main scanning and / or sub scanning, and an image is formed on the object. An image forming apparatus configured to form
The drive means has a longitudinal shape that is parallel to the plate surface of the movable plate and extends in a direction substantially perpendicular to the rotation center axis of the movable plate, and the rotation center axis is positioned in the vicinity of one end thereof. A pair of drive members that support the shaft members, and a longitudinal shape extending in a direction parallel to the rotation center axis, one end of which is fixed to the support member and the other end of the drive A pair of elastically deformable first deformable members connected to the one end of the member and a longitudinal shape, one end of which is fixed to the support member, and the other end is the one end of the drive member A pair of elastically deformable second deformable members connected to the other end opposite to each other, and joined on the second deformable members, and extend and contract in the longitudinal direction of the second deformable members A pair of piezoelectric elements, and by expanding and contracting each piezoelectric element by energization, The second deformable member is bent and deformed, and the drive member is rotated while twisting and deforming each first deformable member to give a torsional moment to each shaft member, and the movable plate An image forming apparatus configured to rotate the image forming apparatus.

Images