DRIVE TRANSMITTING DEVICE, AND IMAGE FORMING APPARATUS

Abstract

In a driving motor that rotates and drives a rotor by a magnetic force generated between a rotor and a stator, a constant velocity joint that transmits a rotation driving force between a driving-side rotating member and a driven-side rotating member. The driving-side rotating member and the driven-side rotating member align in an axial direction and engage with each other. The driving-side rotating member is directly connected to the rotor to function as a driving shaft.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic side view of a printer according to an embodiment of the present invention;

FIG. 2 is an enlarged schematic of a Y process unit for shown in FIG. 1;

FIG. 3A is a vertical cross section of the Y process unit set in the printer and its surroundings;

FIG. 3B is another vertical cross section of the Y process unit removed from the printer and its surroundings;

FIG. 4 is a side view of a constant velocity joint shown in FIGS. 3A and 3B and its surroundings;

FIG. 5 is a cross section of the constant velocity joint and its surroundings;

FIG. 6 is a lateral cross section of a cup of a driving-side rotating member shown in FIG. 5;

FIG. 7 is a lateral cross section of a ball holding member of a driven-side rotating member shown in FIG. 5;

FIG. 8 is a lateral cross section of the cup and the ball holding member engaged in a cylindrical space thereof;

FIG. 9 is a side view of a photoconductor shaft that is to be pressed into a bearing fixed on a rear board of the printer;

FIG. 10 is a side view of the photoconductor shaft positioned in an axial direction;

FIG. 11 is a side view of the photoconductor shaft and a retaining member into which the photoconductor shaft is to be inserted;

FIG. 12 is a side view of the photoconductor shaft, the retaining member, and the driven-side rotating member to be inserted into a shaft hole of the photoconductor shaft;

FIG. 13 is a side view of the photoconduCtor shaft, the retaining member and the driven-side rotating member, into which a male-screw member is to be inserted;

FIG. 14 is a side view of a driving motor to be fixed to a bracket while the ball holding member is engaged into the cup;

FIG. 15 is a cross section of a modified example of the driving motor;

FIG. 16 is an enlarged cross section of an engaged portion of the constant velocity joint of a printer according to a first embodiment of the present invention;

FIG. 17 is a side view of the photoconductor shaft and the driven-side rotating member, into which the photoconductor shaft is to be inserted, of a printer according to a second embodiment of the present invention;

FIG. 18 is a side view of the photoconductor shaft inserted into the driven-side rotating member; and

FIG. 19 is an enlarged elevation view of the constant velocity joint viewed from the driven side of a printer according to a third embodiment of the present invention.

Claims

1. A drive transmitting device comprising: a constant velocity joint that transmits a rotation driving force between a driving-side rotating member and a driven-side rotating member that align in an axial direction and engage each other; anda driving motor that is connected to the driving-side rotating member, whereina rotation driving force of the driving motor is transmitted to a driven member through the constant velocity joint,any one of the driving-side rotating member and the driven-side rotating member includes an outer ring;an inner ring that is located inside the outer ring;a cylindrical space between the outer ring and the inner ring; anda plurality of grooves that extend in an axial direction of the cylindrical space and are located on at least one of the inner peripheral surface of the outer ring and the outer peripheral surface of the inner ring to align in the circular direction,the other one of the driving-side rotating member and the driven-side rotating member includes a ball holding member that holds a plurality of balls in a plurality of through-holes in a cylindrical peripheral wall that align in a circumferential direction,the constant velocity joint transmits the rotation driving force between the driving-side rotating member and the driven-side rotating member via the balls when the ball holding member is arranged in the cylindrical space and the balls are engaged in the grooves, andthe driving-side rotating member is directly connected to a rotor as a driving shaft of the driving motor.

2. The drive transmitting device according to claim 1, wherein at least one of the grooves includes any one of a protrusion that protrudes from a bottom surface of the groove and a protrusion that protrudes in a height direction of the groove from the bottom surface at an end of the groove in an axial direction.

3. The drive transmitting device according to claim 1 further comprising a connecting shaft that is connected to a driven-side end of the driven-side rotating member and is driven and rotates.

4. The drive transmitting device according to claim 3, wherein the driven-side rotating member includes a first through-hole that penetrates in a direction perpendicular to the axial direction at a driven-side end,the connecting shaft includes a shaft hole in which the driven-side end of the driven-side rotating member is arranged in the axial direction;a second through-hole that penetrates in a direction perpendicular to the axial direction and crosses the shaft hole; andtwo slits opposed to each other that extend in the axial direction and divide the shaft hole into two sections,the driven-side end of the driven-side rotating member is arranged in the shaft hole, and the first through-hole and the second through-hole are aligned in a line to screw a male-screw member into the first through-hole and the second through-hole.

5. The drive transmitting device according to claim 3, wherein the connecting shaft includes a first through-hole that penetrates in a direction perpendicular to the axial direction at a driving-side end,the driven-side rotating member includes a shaft hole in which the driving-side end of the connecting shaft is arranged in the axial direction;a second through-hole that penetrates in a direction perpendicular to the axial direction and crosses the shaft hole; andtwo slits opposed to each other that extend in the axial direction and divide the shaft hole into two sections,the driving-side end of the connecting shaft is arranged in the shaft hole, and the first through-hole and the second through-hole are aligned in a line to screw a male-screw member into the first through-hole and the second through-hole.

6. The drive transmitting device according to claim 3 further comprising a bearing that rotatably supports the connecting shaft, wherein the driven-side rotating member includes a shaft hole in which the driving-side end of the connecting shaft is arranged in the axial direction, andthe driven-side end of the driven-side rotating member contacts the driving-side end of the bearing when the driving-side end of the connecting shaft is arranged in the shaft hole.

7. The drive transmitting device according to claim 1, wherein the driving-side rotating member and the driven-side rotating member include a mark at a predetermined position in a rotation direction.

8. An image forming apparatus comprising: an image carrying member that carries a visible image on an endless moving surface;a visible-image forming member that forms a visible image on the endless moving surface; anda drive transmitting device that transmits a driving force to the image carrying member, and includesa constant velocity joint that transmits a rotation driving force between a driving-side rotating member and a driven-side rotating member that align in an axial direction and engage each other; anda driving motor that is connected to the driving-side rotating member, whereina rotation driving force of the driving motor is transmitted to a driven member through the constant velocity joint,any one of the driving-side rotating member and the driven-side rotating member includes an outer ring;an inner ring that is located inside the outer ring;a cylindrical space between the outer ring and the inner ring; anda plurality of grooves that extend in an axial direction of the cylindrical space and are located on at least one of the inner peripheral surface of the outer ring and the outer peripheral surface of the inner ring to align in the circular direction,the other one of the driving-side rotating member and the driven-side rotating member includes a ball holding member that holds a plurality of balls in a plurality of through-holes in a cylindrical peripheral wall that align in a circumferential direction,the constant velocity joint transmits the rotation driving force between the driving-side rotating member and the driven-side rotating member via the balls when the ball holding member is arranged in the cylindrical space and the balls are engaged in the grooves, andthe driving-side rotating member is directly connected to a rotor as a driving shaft of the driving motor.

9. The image forming apparatus according to claim 8, wherein the image carrying member and the drive transmitting device align in a line, and the rotation driving force of the driving motor is transmitted to the image carrying member not through a gear.

10. An image forming apparatus comprising: a latent image carrying member that carries a latent image on an endless moving surface;a developing member that develops the latent image on the latent image carrying member by a developer carried on the endless moving surface; anda drive transmitting device that transmits a driving force to any one of the latent image carrying member and the developing member, and includesa constant velocity joint that transmits a rotation driving force between a driving-side rotating member and a driven-side rotating member that align in an axial direction and engage each other; anda driving motor that is connected to the driving-side rotating member, whereina rotation driving force of the driving motor is transmitted to a driven member through the constant velocity jointsany one of the driving-side rotating member and the driven-side rotating member includes an outer ring;an inner ring that is located inside the outer ring;a cylindrical space between the outer ring and the inner ring; anda plurality of grooves that extend in an axial direction of the cylindrical space and are located on at least one of the inner peripheral surface of the outer ring and the outer peripheral surface of the inner ring to align in the circular direction,the other one of the driving-side rotating member and the driven-side rotating member includes a ball holding member that holds a plurality of balls in a plurality of through-holes in a cylindrical peripheral wall that align in a circumferential direction,the constant velocity joint transmits the rotation driving force between the driving-side rotating member and the driven-side rotating member via the balls when the ball holding member is arranged in the cylindrical space and the balls are engaged in the grooves, andthe driving-side rotating member is directly connected to a rotor as a driving shaft of the driving motor.

11. The image forming apparatus according to claim 10, wherein any one of the latent image carrying member and the developing member and the drive transmitting device align in a line, and the rotation driving force of the driving motor is transmitted to any one of the latent image carrying member and the developing member not through a gear.