Drive transmission device and image forming apparatus incorporating same

Patent metadata

Field	Value
Publication number	US-9880508-B2
Application number	US-201615180162-A
Country	US
Kind code	B2
Filing date	Jun 13, 2016
Priority date	Jun 26, 2015
Publication date	Jan 30, 2018
Grant date	Jan 30, 2018

Abstract

A drive transmission device includes a first rotary body coupled to a drive source, a second rotary body that receives a drive force transmitted from the drive source, a coupling that couples the first rotary body and the second rotary body, and a spring that presses the coupling toward the second rotary body. Each of the first rotary body and the second rotary body includes a plurality of grooves. The coupling has axially opposed first end and second end coupled to the first rotary body and the second rotary body, respectively. The coupling includes a plurality of couplers on a circumferential surface of each of the first end and the second end. The plurality of couplers are axially movable into and out of the plurality of grooves of each of the first rotary body and the second rotary body. The coupling has a spherical end face at the second end.

First claim

What is claimed is:

1. A drive transmission device comprising:
a first rotary body coupled to a drive source;
a second rotary body configured to receive a drive force transmitted from the drive source, the first rotary body and the second rotary body each including a plurality of grooves;
a coupling, including a first end coupled to the first rotary body and a second end axially opposed to the first end and coupled to the second rotary body, to couple the first rotary body and the second rotary body, the coupling including a plurality of couplers on a circumferential surface of each of the first end and the second end, the plurality of couplers being axially movable into and out of the plurality of grooves of each of the first rotary body and the second rotary body, and a spherical end face at the second end;
a spring configured to press the coupling toward the second rotary body from the first rotary body; and
a coupling releaser including a hole into which the coupling is inserted, to separate the coupling and the second rotary body,
wherein the hole of the coupling releaser is elongated in a longitudinal direction of the coupling releaser and includes an inner wall, and
wherein the coupling releaser is movable so that the inner wall of the hole of the coupling releaser contacts a circumferential surface of the coupling, to press the coupling against a force from the spring and to move the coupling axially toward the first rotary body to separate the coupling and the second rotary body.

2. The drive transmission device according to claim 1 , wherein a radius of the circumferential surface of the first end of the coupling is relatively larger than a radius of the circumferential surface of the second end of the coupling.

3. The drive transmission device according to claim 1 , wherein the circumferential surface of each of the first end and the second end of the coupling is spherical.

4. The drive transmission device according to claim 1 , wherein the inner wall of the hole of the coupling releaser has a gradient equal to or substantially equal to a gradient of a circumferential surface of a truncated cone portion of the coupling.

5. The drive transmission device according to claim 1 , wherein the coupling is hollowed out.

6. The drive transmission device according to claim 1 , wherein the coupling is made of a resin material reinforced by carbon fibers or glass fibers.

7. The drive transmission device according to claim 1 ,
wherein the coupling further includes a truncated cone portion between the first end and the second end, and
wherein the truncated cone portion includes a circumferential surface inclined at an angle of 45 degrees or less with respect to a direction perpendicular to an axis of the truncated cone portion.

8. The drive transmission device according to claim 1 , wherein different couplers of the plurality of couplers are used for different drive transmission depending on a rotational direction of the coupling.

9. The drive transmission device according to claim 8 ,
wherein the plurality of couplers includes four couplers on the circumferential surface of each of the first end and the second end, and
wherein the four couplers are used for drive transmission in a first rotational direction of the coupling and two of the four couplers are additionally used for drive transmission in a second rotational direction of the coupling opposite the first rotational direction.

10. The drive transmission device according to claim 8 , wherein each of couplers of the plurality of couplers used for drive transmission in both a first rotational direction and a second rotational direction, opposite the first rotational direction, of the coupling includes a cross section shaped as a rectangle with rounded corners including a pair of planar portions parallel to each other and a pair of arc portions.

11. An image forming apparatus comprising:
a main body; and
a drive transmission device included in the main body, the drive transmission device including:
a first rotary body coupled to a drive source;
a second rotary body configured to receive a drive force transmitted from the drive source, the first rotary body and second rotary body each including a plurality of grooves;
a coupling, including a first end coupled to the first rotary body and a second end axially opposed to the first end and coupled to the second rotary body, to couple the first rotary body and the second rotary body,
the coupling including a plurality of couplers on a circumferential surface of each of the first end and the second end, the plurality of couplers being axially movable into and out of the plurality of grooves of each of the first rotary body and the second rotary body,
the coupling including a spherical end face at the second end; and
a spring configured to press the coupling toward the second rotary body from the first rotary body, wherein the coupling further includes a truncated cone portion between the first end and the second end, the truncated cone portion including a circumferential surface inclined with respect to an axis of the truncated cone portion, such that a radius of the circumferential surface of the first end of the coupling is relatively larger than a radius of the circumferential surface of the second end of the coupling.

12. The image forming apparatus of claim 11 , wherein the drive transmission device further includes:
a coupling releaser including a hole into which the coupling is inserted, to separate the coupling and the second rotary body,
wherein the hole of the coupling releaser is elongated in a longitudinal direction of the coupling releaser and includes an inner wall, and
wherein the coupling releaser is moved so that the inner wall of the hole of the coupling releaser contacts a circumferential surface of the coupling, to press the coupling against a force from the spring and to move the coupling axially toward the first rotary body to separate the coupling and the second rotary body.

Assignees

• Tomita Kenji
• Uji Kentaro
• Ricoh Co Ltd

Inventors

• Tomita Kenji
• Uji Kentaro

Classifications

• G03G21/1647

  Mechanical connection means · CPC title

• G03G15/757 Primary

  Drive mechanisms for photosensitive medium, e.g. gears · CPC title

• G03G2221/1657

  transmitting mechanical drive power · CPC title

• F16D1/10

  Quick-acting couplings in which the parts are connected by simply bringing them together axially · CPC title

• F16D3/44

  the intermediate member being connected to the coupling parts by ridges, pins, balls, or the like guided in grooves or between cogs · CPC title