Image forming apparatus

Abstract

A constant velocity joint includes a first rotation body and a second rotation body. The first rotation body includes a cup unit, a shaft, and ribs that project from the cup unit and connect the cup unit to the shaft. One of the first rotation body and the second rotation body transmits a rotational driving force to other one of the first rotation body and the second rotation body through balls. The first rotation body is so formed that the cup unit and the shaft are formed into one piece using resin material. Moreover, the rib is so formed into one piece with the cup unit and the shaft using resin material.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view for explaining a printer according to a first embodiment of the present invention;

FIG. 2 is an enlarged view for explaining a processing unit for Y of the printer according to the first embodiment;

FIG. 3A is a longitudinal cross section of the processing unit for Y and its surrounding structure;

FIG. 3B is a longitudinal cross section of the processing unit for Y in the course of being detached from the printer and its surrounding structure;

FIG. 4 is a cross section of a constant velocity joint of the printer and its surrounding structure;

FIG. 5 is a perspective view of a cup unit of a female joint unit of the constant velocity joint;

FIG. 6 is a lateral cross section of the cup unit;

FIG. 7 is a lateral cross section of a ball holder of a male joint unit of the constant velocity joint;

FIG. 8 is a lateral cross section of the cup unit and the ball holder inserted into an annular space of the cup unit;

FIG. 9 is a longitudinal cross section of the cup unit and the ball holder inserted into the annular space of the cup unit;

FIG. 10A is a longitudinal cross section of a processing unit for Y and its surrounding structure according to a second embodiment of the present invention;

FIG. 10B is a longitudinal cross section of the processing unit for Y in the course of being detached from the printer and its surrounding structure according to the second embodiment;

FIG. 11 is a cross section of the constant velocity joint of the printer and its surrounding structure according to the second embodiment;

FIG. 12 is a lateral cross section of the cup unit of the female joint unit of the constant velocity joint;

FIG. 13 is a lateral cross section of the ball holder of the male joint unit of the constant velocity joint;

FIG. 14 is a lateral cross section of the cup unit and the ball holder inserted into the annular space of the cup unit; and

FIG. 15 is a lateral cross section of the cup unit and the ball holder inserted into the annular space of the cup unit.

Claims

1. A constant velocity joint comprising: a first rotation body including a cup-shaped cup unit formed by opening one end in an axis direction of an annular space created between an outer ring and an inner ring inside the outer ring while closing other end thereof;a plurality of grooves provided on at least one of an inner surface of the outer ring and an outer surface of the inner ring so as to be aligned in a circumferential direction while extending in the axis direction; anda shaft that projects from the other end of the cup unit and extends on a central axis line of the cup unit; anda second rotation body including a ball holder that holds a ball in each of a plurality of through holes, the through holes being provided on a cylindrical peripheral wall so as to be aligned in a peripheral direction thereof, whereinone of the first rotation body and the second rotation body transmits a rotational driving force to other one of the first rotation body and the second rotation body through the balls while the ball holder is inserted into the annular space and the balls held by the ball holder are engaged in the grooves within the annular space, andthe first rotation body is so formed that the cup unit and the shaft are formed into one piece using resin material, and at least one rib, that projects from other end of the cup unit and connects the cup unit with the shaft, is so formed that the rib is formed into one piece with the cup unit and the shaft using resin material.

2. The constant velocity joint according to claim 1, wherein a plurality of ribs is aligned in a rotational direction of the shaft at predetermined pitches.

3. The constant velocity joint according to claim 1, wherein the rib is provided on an extended line of the grooves.

4. The constant velocity joint according to claim 1, wherein the ball holder is formed of resin material.

5. The constant velocity joint according to claim 1, wherein the resin material that forms the cup unit, the shaft, and the rib is one used in the injection molding process.

6. An image forming apparatus comprising: a latent image carrier that caries a latent image on a surface that is movable endlessly;a latent image forming unit that forms the latent image on the surface;a developing member that develops the latent image on the latent image carrier by using a developing agent into a visible image;a transfer unit that transfers the visible image to any one of another surface of the surface endless mover and a recording member held by the surface endless mover;a drive transmission mechanism that transmits a driving force from a driving source to at least one of the latent carrier, the developing member, and the surface endless mover; anda constant velocity joint provided within the drive transmission mechanism, the constant velocity joint including a first rotation body including a cup-shaped cup unit formed by opening one end in an axis direction of an annular space created between an outer ring and an inner ring inside the outer ring while closing other end thereof;a plurality of grooves provided on at least one of an inner surface of the outer ring and an outer surface of the inner ring so as to be aligned in a circumferential direction while extending in the axis direction; anda shaft that projects from the other end of the cup unit and extends on a central axis line of the cup unit; anda second rotation body including a ball holder that holds a ball in each of a plurality of through holes, the through holes being provided on a cylindrical peripheral wall so as to be aligned in a peripheral direction thereof, whereinone of the first rotation body and the second rotation body transmits a rotational driving force to other one of the first rotation body and the second rotation body through the balls while the ball holder is inserted into the annular space and the balls held by the ball holder are engaged in the grooves within the annular space, andthe first rotation body is so formed that the cup unit and the shaft are formed into one piece using resin material, and at least one rib, that projects from the other end of the cup unit and connects the cup unit with the shaft, is so formed that the rib is formed into one piece with the cup unit and the shaft using resin material.

7. The image forming apparatus according to claim 6, wherein the constant velocity joint includes a plurality of ribs that are aligned in a rotational direction of the shaft at predetermined pitches.

8. The image forming apparatus according to claim 6, wherein each of the rib is provided on an extending line of a corresponding one of the groove.

9. The image forming apparatus according to claim 6, wherein the ball holder is formed of resin material.

10. The image forming apparatus according to claim 6, wherein the constant velocity joint includes the cup unit, the shaft, and the ribs that are formed of resin material, the resin material being one used in an injection molding process.

11. The image forming apparatus according to claim 6, wherein a driving motor having a rotational driving shaft is used as a driving source and a photo conductor that rotates around a rotational driven shaft is used as a latent image carrier as well, and the rotational driving shaft and the rotational driven shaft are coupled to each other through the constant velocity joint.

12. The image forming apparatus according to claim 11, wherein the photo conductor has such a structure that the rotational driven shaft pierce fits into a central hole provided in an axis direction of the photo conductor.

13. The image forming apparatus according to claim 11, wherein any one of the first rotation body or the second rotation body, and the rotational driving shaft of the driving motor are press fit into the other one in the axis direction to connect therebetween in the axis direction.

14. The image forming apparatus according to claim 12, wherein the rotational driven shaft is rotatably supported by a shaft bearing secured to an apparatus body, and the rotational driven shaft is inserted into a cylindrical member having a diameter larger than that of the rotational driven shaft to place the cylindrical member at a position between the first rotation body or the second rotation body and the shaft bearing.

15. A constant velocity joint comprising: a first rotation body including a cup-shaped cup unit formed by opening one end in an axis direction of an annular space created between an outer ring and an inner ring inside the outer ring while closing other end thereof;a plurality of grooves provided on at least one of an inner surface of the outer ring and an outer surface of the inner ring so as to be aligned in a circumferential direction while extending in the axis direction; anda second rotation body including a ball holder that holds a ball in each of a plurality of through holes, the through holes being provided on a cylindrical peripheral wall so as to be aligned in a peripheral direction thereof, whereina rotational driving force of one of the first rotation body and the second rotation body is transmitted to the other one of the first rotation body and the second rotation body through the plurality of balls while the ball holder is inserted into the annular space and the balls held by the ball holder are engaged in the grooves within the annular space, andthe outer ring has a multi-layered structure including an innermost layer that is formed of resin material and that defines the inner surface and a metal layer that is formed of metal material and that is positioned outside the innermost layer.

16. The constant velocity joint according to claim 15, wherein the outer ring has a two-layered structure including the innermost layer formed of the resin material and the outermost layer formed of the metal material.

17. The constant velocity joint according to claim 15, wherein the cup unit includes a cup base body that is so formed that the innermost layer and the inner ring are formed into one piece using same resin material, the cup base body fitting into a cylindrical metal body composing the outermost layer.

18. The constant velocity joint according to claim 15, wherein the cylindrical metal body is so formed that a shaft extending on a central axis of the metal body is formed into one piece with the cylindrical metal body using the same metal material as the cylindrical metal body.

19. The constant velocity joint according to claim 15, wherein the ball holder is formed of resin material.

20. The constant velocity joint according to claim 15, wherein the resin material is one used in the injection molding process.