ACTUATOR, OPTICAL SCANNER, AND IMAGE FORMING APPARATUS

• US 20120147445A1
• Filed: 12/06/2011
• Published: 06/14/2012
• Est. Priority Date: 12/08/2010
• Status: Active Grant

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: MIZOGUCHI, Yasushi
• Granted Patent: US 9,186,908 B2
• Time in Patent Office: Days
• US Class Current: 359/212.1
• CPC Class Codes: B41J 2/471 using dot sequential main scanning by means of a light deflector, e.g. a rotating polygonal mirror
• CPC Class Codes: B81B 2201/042 Micromirrors, not used as optical switches
• CPC Class Codes: B81B 3/0062 Devices moving in two or more dimensions, i.e. having special features which allow movement in more than one dimension
• CPC Class Codes: G02B 26/085 the reflecting means being moved or deformed by electromagnetic means
• CPC Class Codes: G02B 26/105 with one or more pivoting mirrors or galvano-mirrors G02B26/101 takes precedence

Abstract

An actuator includes a movable member which rotates around a rotation axis, a plurality of connecting members which extend from the movable member through a shaft and are disposed in the vicinity of the outer circumference of the movable member at equal intervals in the plan view as viewed in a thickness direction of the movable member, and a support unit which supports each of the plurality of connecting members. Each of the plurality of connecting members has a driving portion rotatably connected with the support unit, and the shaft connecting the movable member and the driving portion. A first connecting portion that connects the movable member with the shaft and that is disposed opposite to a corresponding second connecting portion that connects the driving portion with the shaft through the movable member so that the movable member is interposed between the first connecting portion and the second connecting portion.

Claims

1. An actuator comprising:

a movable member which rotates around a rotation axis;

a plurality of connecting members which extend from the movable member through a shaft and are disposed near an outer circumference of the movable member at equal intervals in the plan view as viewed in a thickness direction of the movable member; and

a support unit which supports each of the plurality of connecting members, wherein

each of the plurality of connecting members has a driving portion rotatably connected with the support unit, and the shaft connecting the movable member and the driving portion, and

a first connecting portion that connects the movable member with the shaft and that is disposed opposite to a corresponding second connecting portion that connects the driving portion with the shaft through the movable member so that the movable member is interposed between the first connecting portion and the second connecting portion in a direction perpendicular to the thickness direction.

2. The actuator according to claim 1, wherein the shaft has a bending point at which the shaft starts to bend in a plane perpendicular to the thickness direction of the movable member.

3. The actuator according to claim 2, wherein the shaft has a stress relieving portion disposed at a position different from the bending point to relieve stress acting on the shaft.

4. The actuator according to claim 3, wherein the stress relieving portion is thinner than a remainder of the shaft.

5. The actuator according to claim 3, wherein the stress relieving portion has an elongated part extending in a zigzag shape in a longitudinal direction of the elongated part along the plane perpendicular to the thickness direction of the movable member.

6. The actuator according to claim 3, wherein the stress relieving portion is connected with the movable member.

7. The actuator according to claim 3, wherein the stress relieving portion is disposed between the first connecting portion and the bending point located closest to the first connecting portion.

8. The actuator according to claim 1, wherein

the movable member has a circular shape in the plan view as viewed in the thickness direction of the movable member, and

a center point of the circular shape is located on a segment connecting the first connecting portion and the second connecting portion in the plan view as viewed in the thickness direction of the movable member.

9. The actuator according to claim 1, wherein

the movable member has a circular shape in the plan view as viewed in the thickness direction of the movable member, and

a center point of the circular shape is located spaced apart from a segment connecting the first connecting portion and the second connecting portion in the plan view as viewed in the thickness direction of the movable member.

10. The actuator according to claim 1, further comprising:

a displacement producing unit that rotates the movable member around the rotation axis, wherein

the displacement producing unit has a permanent magnet provided on the driving portion of each of the plurality of connecting members, and a coil generating a magnetic field acting on the permanent magnet.

11. The actuator according to claim 10, wherein

the permanent magnet is provided in a position so that each pole of the permanent magnet is located opposite to each other in the thickness direction of the movable member, and

the coil is adapted to generate the magnetic field in the direction perpendicular to the thickness direction of the movable member.

12. The actuator according to claim 10, wherein

the rotation axis includes a first rotation axis and a second rotation axis perpendicular to the first rotation axis, and

the movable member independently rotates around the first rotation axis and the second rotation axis in accordance with the displacement of the driving portion effected by the displacement producing unit.

13. The actuator according to claim 1, wherein the support unit is a frame surrounding the movable member.

14. The actuator according to claim 13, wherein

the support unit has the same number of cutouts as the number of the plurality of connecting members to provide cutout portions of the frame shape of the support unit, and

the driving portion is disposed at each of the cutouts with one-to-one correspondence.

15. An optical scanner comprising:

a movable member which contains a light reflection portion having light reflectivity and rotates around a rotation axis;

a plurality of connecting members which extend from the movable member through a shaft and are disposed near an outer circumference of the movable member at equal intervals in a plan view as viewed in a thickness direction of the movable member; and

a support unit which supports each of the plurality of connecting members, wherein

each of the plurality of connecting members has a driving portion rotatably connected with the support unit, and the shaft connecting the movable member and the driving portion, and

a first connecting portion that connects the movable member with the shaft and that is disposed opposite to a corresponding second connecting portion that connects the driving portion with the shaft through the movable member so that the movable member is interposed between the first connecting portion and the second connecting portion.

16. An image forming apparatus comprising:

a light emitting unit which emits light; and

an optical scanner which reflects the light received from the light emitting unit to perform light scanning, wherein

the optical scanner includes;

a movable member which contains a light reflection portion having light reflectivity and rotates around a rotation axis;

a plurality of connecting members which extend from the movable member through a shaft and are disposed near an outer circumference of the movable member at equal intervals in a plan view as viewed in a thickness direction of the movable member;

a support unit which supports each of the plurality of connecting members;

each of the plurality of connecting members has a driving portion rotatably connected with the support unit, and the shaft connecting the movable member and the driving portion; and

first connecting portion that connects the movable member with the shaft and that is disposed opposite to a corresponding second connecting portion that connects the driving portion with the shaft through the movable member so that the movable member is interposed between the first connecting portion and the second connecting portion.

17. An actuator comprising:

a movable plate which has light reflectivity;

a support unit which supports the movable plate at a position near an outer circumference of the movable plate; and

a plurality of connecting members that connect the movable plate with the support unit and that are disposed near the outer circumference of the movable plate at equal intervals in a circumferential direction of the movable plate in a plan view of the movable plate, wherein

each of the plurality of connecting members has a driving portion disposed away from the movable plate and rotatable with respect to the support unit, and an elongated shaft which connects the movable plate with the driving portion, and

one end of the shaft corresponds to a movable plate side connecting point connected with the movable plate, while the other end of the shaft corresponds to a driving portion side connecting point connected with the driving portion, the movable plate side connecting point being disposed opposite to the driving portion side connecting point through the movable plate so that the movable plate is interposed between the movable plate side connecting point and the driving portion side connecting point.

18. The actuator according to claim 17, wherein the shaft has at least one bending point where the shaft is bent at an intermediate portion of the shaft in a longitudinal direction of the shaft.

19. The actuator according to claim 18, wherein

the movable plate has a circular shape in the plan view, and

the bending point includes a portion that is bent in a direction to follow a curve of the circumference of the circular shape.

20. The actuator according to claim 18, wherein the shaft has a stress relieving portion disposed at a position different from the bending point to relieve stress.

21. The actuator according to claim 20, wherein the stress relieving portion is thinner than a remainder of the shaft.

22. The actuator according to claim 20, wherein the stress relieving portion has a part extending in a zigzag shape.

23. The actuator according to claim 20, wherein the stress relieving portion is disposed close to the movable plate side connecting point.

24. The actuator according to claim 20, wherein

a plurality of the bending points are provided, and

the stress relieving portion is disposed at a position between the movable plate side connecting point and one of the plurality of bending points located closest to the movable plate side connecting point.

25. The actuator according to claim 17, wherein

the movable plate has a circular shape in the plan view, and

a center point of the circular shape is located on a line connecting the movable plate side connecting point and the driving portion side connecting point in the plan view of the movable plate.

26. The actuator according to claim 17, wherein

the movable plate has a circular shape in the plan view, and

a center point of the circular shape is located away from a line connecting the movable plate side connecting point and the driving portion side connecting point in the plan view of the movable plate.

27. The actuator according to claim 17, further comprising:

a displacement unit that displaces the movable plate with respect to the support unit, wherein

the displacement unit has a permanent magnet provided on the driving portion of each of the plurality of connecting members, and a coil generating a magnetic field acting on the permanent magnet.

28. The actuator according to claim 27, wherein

the permanent magnet is provided in a position so that each pole of the permanent magnet is located opposite to each other in the thickness direction of the movable plate, and

the coil is adapted to generate the magnetic field in the direction perpendicular to the thickness direction of the movable plate.

29. The actuator according to claim 27, wherein the movable plate independently rotates around an X axis and a Y axis as two axes of the movable plate perpendicular to each other in the plan view by forces transmitted via the plurality of connecting members when the displacement unit is operated.

30. The actuator according to claim 17, wherein the support unit is a frame-shaped wall surrounding the movable plate.

31. The actuator according to claim 30, wherein the wall has the same number of cutouts as the number of the plurality of connecting members to provide cutout portions of the wall, and

the driving portion is disposed at each of the cutouts with a one-to-one correspondence.

32. An optical scanner comprising:

a movable plate which has light reflectivity;

a support unit which supports the movable plate at a position near an outer circumference of the movable plate; and

a plurality of connecting members that connects the movable plate with the support unit and that is disposed near the outer circumference of the movable plate at equal intervals in a circumferential direction of the movable plate in a plan view of the movable plate, wherein

each of the plurality of connecting members has a driving portion disposed away from the movable plate and rotatable with respect to the support unit, and an elongated shaft which connects the movable plate with the driving portion, and

one end of the shaft corresponds to a movable plate side connecting point connected with the movable plate, while the other end of the shaft corresponds to a driving portion side connecting point connected with the driving portion, the movable plate side connecting point being disposed opposite to the driving portion side connecting point through the movable plate so that the movable plate is interposed between the movable plate side connecting point and the driving portion side connecting point.

33. An image forming apparatus comprising:

a light emitting unit which emits light; and

an optical scanner which reflects the light received from the light emitting unit to perform light scanning, wherein

the optical scanner includes;

a movable plate which has light reflectivity and reflects the light received from the light emitting unit;

a support unit which supports the movable plate at a position near an outer circumference of the movable plate, and

a plurality of connecting members that connect the movable plate with the support unit and that are disposed near the outer circumference of the movable plate at equal intervals in a circumferential direction of the movable plate in a plan view of the movable plate, wherein

each of the plurality of connecting members has a driving portion disposed away from the movable plate and rotatable with respect to the support unit, and an elongated shaft which connects the movable plate with the driving portion, and

one end of the shaft corresponds to a movable plate side connecting point connected with the movable plate, while the other end of the shaft corresponds to a driving portion side connecting point connected with the driving portion, the movable plate side connecting point being disposed opposite to the driving portion side connecting point through the movable plate so that the movable plate is interposed between the movable plate side connecting point and the driving portion side connecting point.