JP2017207565A - Rotation driving device and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotation driving device that prevents the occurrence of a trouble that a driving coupling is prevented from moving along the axial direction of a rotation shaft part even after the lapse of time, and an image forming apparatus.SOLUTION: A rotation driving device comprises: an intermediate member 67 that is installed in an inner diameter part of a drive coupling 64 to reduce the area where the drive coupling 64 is in contact with a rotation shaft part 65, and can move along the axial direction of the rotation shaft part 65 together with the drive coupling 64; and a compression spring 66 (urging member) that urges the drive coupling 64 and intermediate member 67 in a direction to approach a driven coupling 13d of a developing roller 13a (rotation target body). The intermediate member 67 is formed of a material having a coefficient of friction smaller than that of the drive coupling 64.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a rotation driving device that rotationally drives a rotating member, and an image forming apparatus such as a copying machine, a printer, a facsimile, or a complex machine or a printing machine including the rotation driving device.

  2. Description of the Related Art Conventionally, in an image forming apparatus such as a copying machine or a printer, a technique for installing a rotation driving device that rotationally drives a rotating body such as a developing roller, a conveying screw, a photosensitive drum, a transfer roller, and a registration roller is known. (For example, refer to Patent Document 1).

Specifically, in Patent Document 1, a process cartridge in which a developing roller (a rotating body) is rotatably installed is configured to be detachable from an image forming apparatus main body in which a rotation driving device is installed.
A driven coupling (cartridge side coupling) is installed on the shaft portion of the developing roller. On the other hand, the rotational drive device is provided with a drive coupling that is fitted to the driven coupling and is rotationally driven by the drive source together with the rotation shaft. The drive coupling is installed so as to be movable in the axial direction with respect to the rotating shaft portion. Further, an urging member (coil spring) for urging the drive coupling toward the driven coupling is wound around the rotating shaft portion.

With such a configuration, when the process cartridge is moved in the axial direction and attached to the image forming apparatus main body, the driven coupling engages with the drive coupling of the rotary drive device, and the rotary drive device Thus, it is possible to transmit the drive from the developing roller to the developing roller.
Here, since the drive coupling is installed so as to be movable in the axial direction while being urged by the urging member with respect to the rotating shaft portion, when the process cartridge is mounted on the image forming apparatus main body, Even if the drive coupling does not fit into the driven coupling and the tips collide with each other, the drive coupling moves so as to escape in the axial direction, and then the drive coupling is driven to rotate. As a result, the posture in the rotational direction is shifted and both couplings are fitted. Thereby, the front-end | tip parts of a drive coupling and a driven coupling collide, and the malfunction which a drive coupling and a driven coupling are damaged is prevented.

  The conventional rotary drive device has a drive coupling that slides over the rotating shaft over time when the drive coupling or rotating shaft is made of a metal material in order to improve its durability and mechanical strength. The sliding resistance may increase. In such a case, if the driving coupling does not fit into the driven coupling and the tips collide with each other, the driving coupling becomes difficult to move along the axial direction of the rotating shaft. There was a possibility that both couplings were damaged.

  The present invention has been made to solve the above-described problems, and the rotational drive device, in which the drive coupling is less likely to move along the axial direction of the rotary shaft portion even over time, and the rotational drive device, An object is to provide an image forming apparatus.

  The rotational drive device according to the present invention is a rotational drive device that rotationally drives a rotated body, wherein the drive coupling is fitted to a driven coupling installed on a shaft portion of the rotated body, and the drive is performed by a drive source. A rotating shaft that is driven to rotate together with the coupling, and an inner diameter portion of the driving coupling so that an area in which the driving coupling contacts the rotating shaft is reduced; An intermediate member configured to be movable along the axial direction of the portion, and a biasing member that biases the drive coupling and the intermediate member in a direction approaching the driven coupling, wherein the intermediate member is These are made of a material having a smaller friction coefficient than that of the drive coupling.

  According to the present invention, it is possible to provide a rotary drive device and an image forming apparatus that are less likely to cause a problem that the drive coupling is difficult to move along the axial direction of the rotary shaft portion over time.

1 is an overall configuration diagram illustrating an image forming apparatus according to an embodiment of the present invention. It is a block diagram which shows an image creation part. (A) The schematic sectional view which looked at the upper part of the developing device in the longitudinal direction, (B) The schematic sectional view which looked at the lower part of the developing device in the longitudinal direction. (A) Schematic showing the state where the driven coupling of the developing roller is fitted to the driving coupling of the rotary drive device, and (B) Schematic showing the state where the claws of the driven coupling and the driving coupling collide with each other. Figure. It is a schematic sectional drawing which shows the state which the driven coupling of the developing roller fitted to the drive coupling of the rotation drive device. It is a perspective view which shows the principal part of a rotation drive device. It is a perspective view which shows the axial part of a developing roller. It is a perspective view which shows the state which the driven coupling of the developing roller was fitted to the drive coupling of the rotation drive device. It is sectional drawing which shows a drive coupling, an intermediate member, and a rotating shaft part.

  Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. In addition, in each figure, the same code | symbol is attached | subjected to the part which is the same or it corresponds, The duplication description is simplified or abbreviate | omitted suitably.

First, the overall configuration and operation of the image forming apparatus will be described with reference to FIG.
In FIG. 1, 1 is a tandem color copier as an image forming apparatus, 2 is a writing unit that emits laser light based on input image information, 3 is a document conveying unit that conveys a document D to a document reading unit 4, and 4 is An original reading unit that reads image information of the original D, 7 is a paper feeding unit that accommodates a recording medium P such as transfer paper, 9 is a registration roller (timing roller) that adjusts the conveyance timing of the recording medium P, 10Y, 10M, Reference numerals 10C and 10BK denote process cartridges (image forming units) on which toner images of respective colors (yellow, magenta, cyan, and black) are formed.

  Reference numeral 17 denotes an intermediate transfer belt onto which a plurality of color toner images are transferred, 18 denotes a secondary transfer roller for transferring the color toner image on the intermediate transfer belt 17 onto the recording medium P, and 19 denotes an intermediate transfer belt. An intermediate transfer belt cleaning unit 20 for cleaning 17; a primary transfer roller 20 for transferring a toner image formed on the photosensitive drum 12 of each of the process cartridges 10Y, 10M, 10C, and 10BK on the intermediate transfer belt 17; Reference numeral 21 denotes a driving roller for driving the intermediate transfer belt 17, 30 a fixing device for fixing an unfixed image on the recording medium P, and 50Y, 50M, 50C, and 50BK each containing toner of each color (yellow, magenta, cyan, black). The toner cartridge (toner container) is shown.

Hereinafter, an operation during normal color image formation in the image forming apparatus will be described.
Note that FIG. 2 can also be referred to for the image forming process performed on the photosensitive drums 12 of the process cartridges 10Y, 10M, 10C, and 10BK.

First, the document D is transported from the document table in the direction of the arrow in the drawing by the transport rollers of the document transport unit 3 and placed on the contact glass 5 of the document reading unit 4. Then, the document reading unit 4 optically reads the image information of the document D placed on the contact glass 5.
Specifically, the document reading unit 4 scans the image of the document D on the contact glass 5 while irradiating light emitted from an illumination lamp. Then, the light reflected by the document D is imaged on the color sensor via the mirror group and the lens. The color image information of the document D is read for each RGB (red, green, blue) color separation light by the color sensor, and then converted into an electrical image signal. Further, color conversion processing, color correction processing, spatial frequency correction processing, and the like are performed by the image processing unit based on the RGB color separation image signals to obtain yellow, magenta, cyan, and black color image information.

  Then, the image information of each color of yellow, magenta, cyan, and black is transmitted to the writing unit 2. The writing unit 2 emits laser light L (see FIG. 2) based on the image information of each color toward the corresponding photosensitive drum 12.

On the other hand, the photosensitive drums 12 of the four process cartridges 10Y, 10M, 10C, and 10BK are rotated counterclockwise in FIG. First, the surface of the photosensitive drum 12 is uniformly charged at a portion facing the charging device 14 (charging roller) (this is a charging process). Thus, a charged potential is formed on the photosensitive drum 12. Thereafter, the surface of the charged photosensitive drum 12 reaches the irradiation position of each laser beam L.
In the writing unit 2, laser light corresponding to the image signal is emitted from the four light sources corresponding to each color. Each laser beam passes through a separate optical path for each of the yellow, magenta, cyan, and black color components (this is an exposure process).

  The laser beam corresponding to the yellow component is applied to the surface of the photosensitive drum 12 of the first process cartridge 10Y from the left side of the drawing. At this time, the yellow component laser light is scanned in the rotation axis direction (main scanning direction) of the photosensitive drum 12 by a polygon mirror that rotates at high speed. Thus, an electrostatic latent image corresponding to the yellow component is formed on the photosensitive drum 12 after being charged by the charging device 14.

  Similarly, the laser beam corresponding to the magenta component is irradiated on the surface of the photosensitive drum 12 of the second process cartridge 10M from the left side of the paper, and an electrostatic latent image corresponding to the magenta component is formed. The cyan component laser light is applied to the surface of the photosensitive drum 12 of the third process cartridge 10C from the left side of the drawing, thereby forming an electrostatic latent image of the cyan component. The black component laser beam is applied to the surface of the photoconductive drum 12 of the fourth process cartridge 10BK from the left side of the drawing to form a black component electrostatic latent image.

Thereafter, the surface of the photosensitive drum 12 on which the electrostatic latent images of the respective colors are formed reaches a position facing the developing device 13 (developing unit). Then, each color toner is supplied from each developing device 13 onto the photosensitive drum 12, and the latent image on the photosensitive drum 12 is developed (this is a developing step).
Thereafter, the surface of the photoconductor drum 12 after the development process reaches a portion facing the intermediate transfer belt 17. Here, a primary transfer roller 20 is installed at each facing portion so as to abut on the inner peripheral surface of the intermediate transfer belt 17. Then, the toner images of the respective colors formed on the photosensitive drums 12 of the process cartridges 10Y, 10M, 10C, and 10BK are sequentially superimposed and transferred onto the intermediate transfer belt 17 at the position of the primary transfer roller 20. (This is a primary transfer step.)

Then, the surface of the photosensitive drum 12 after the primary transfer process reaches a position facing the cleaning blade 15 (cleaning unit). Then, the untransferred toner remaining on the photosensitive drum 12 is collected by the cleaning blade 15 (cleaning process).
Thereafter, the surface of the photoconductive drum 12 passes through the static eliminating unit, and a series of image forming processes on the photoconductive drum 12 is completed.

On the other hand, the intermediate transfer belt 17 on which the toner images of the respective colors on the photosensitive drums 12 of the process cartridges 10Y, 10M, 10C, and 10BK are superimposed (transferred) is stretched. Is rotated clockwise in the figure, and reaches a position facing the secondary transfer roller 18. Then, the color toner image carried on the intermediate transfer belt 17 is transferred onto the recording medium P at a position facing the secondary transfer roller 18 (secondary transfer step).
Thereafter, the surface of the intermediate transfer belt 17 reaches the position of the intermediate transfer belt cleaning unit 19. Then, the untransferred toner adhered on the intermediate transfer belt 17 is collected by the intermediate transfer belt cleaning unit 19, and a series of transfer processes in the intermediate transfer belt 17 is completed.

Here, the recording medium P conveyed between the intermediate transfer belt 17 and the secondary transfer roller 18 (secondary transfer nip) is conveyed from the paper supply unit 7 via the registration roller 9 and the like. Is.
Specifically, the recording medium P fed by the paper feeding roller 8 from the paper feeding unit 7 that stores the recording medium P is guided to the registration roller 9 after passing through the conveyance guide. The recording medium P that has reached the registration roller 9 is conveyed toward the secondary transfer nip at the same timing.

Then, the recording medium P on which the full color image is transferred is guided to the fixing device 30 by the conveyance belt. In the fixing device 30, the color image is fixed on the recording medium P at the nip between the fixing belt and the pressure roller.
Then, the recording medium P after the fixing step is discharged as an output image outside the apparatus main body 1 by a paper discharge roller, and a series of image forming processes is completed.

Next, the process cartridge 10 (image forming unit) will be described in detail with reference to FIGS.
As shown in FIG. 2, the process cartridge 10 includes a photosensitive drum 12 as an image carrier, a charging device 14 (charging roller) for charging the photosensitive drum 12, and a latent image formed on the surface of the photosensitive drum 12. A developing device 13 (developing unit) for developing, a cleaning blade 15 (cleaning unit) for removing untransferred toner on the photosensitive drum 12, and a lubricant supplying device 16 (lubricant supplying) for supplying a lubricant onto the photosensitive drum 12 Part), etc. The process cartridge 10 is configured to be detachable (replaceable) from the apparatus main body 1.
Since the process cartridges of the respective colors have almost the same structure, the process cartridges, the photosensitive drums, and the developing devices in FIG. 2, FIG. 3 and the like are excluded from the alphabets (Y, C, M, BK). Illustrated.

Here, the photosensitive drum 12 as an image bearing member is a negatively charged organic photosensitive member, and a photosensitive layer or the like is provided on a drum-shaped conductive support.
In the photosensitive drum 12, an undercoat layer as an insulating layer, a charge generation layer and a charge transport layer as a photosensitive layer, and a protective layer (surface layer) are sequentially laminated on a conductive support as a base layer. As the conductive support (base layer) of the photosensitive drum 12, a conductive material having a volume resistance of 10 ¹⁰ Ωcm or less can be used.
The photosensitive drum 12 is rotationally driven by a main motor in a predetermined direction (counterclockwise in FIG. 2). In the present embodiment, a charging device 14 (charging roller), a lubricant supply roller 16a, and a conveying screw 15b, which will be described later, are also moved in the directions of the arrows shown in FIG. Driven by rotation.

The charging device 14 is a charging roller (roller member) formed by coating an outer periphery of a conductive metal core (shaft portion) with a medium-resistance elastic layer. The charging drum 14 rotates the photosensitive drum 12 with respect to the lubricant supply device 16. It is disposed so as to contact the photosensitive drum 12 on the downstream side in the direction.
A predetermined voltage (charging bias) is applied to the charging device 14 from a power supply unit installed in the apparatus main body 1, thereby uniformly charging the surface of the opposing photosensitive drum 12.
In the present embodiment, the charging device 14 is in contact with the photosensitive drum 12, but the charging device 14 may be opposed to the photosensitive drum 12 with a small gap therebetween.

The cleaning blade 15 (cleaning unit) is disposed on the downstream side in the rotation direction of the photosensitive drum 12 with respect to the lubricant supply device 16. The cleaning blade 15 is made of a rubber material such as urethane rubber, and is in contact with the surface of the photosensitive drum 12 at a predetermined angle and a predetermined pressure. As a result, deposits such as untransferred toner adhering to the photosensitive drum 12 are mechanically scraped and collected in the process cartridge 10. Then, the toner collected in the process cartridge 10 is directed as a waste toner toward a waste toner collection container (removably installed on the back side in the direction perpendicular to the paper surface of the apparatus main body 1 in FIG. 1) by the transport screw 15b. Be transported.
The cleaning blade 15 in the present embodiment also functions as a thinning blade that thins the lubricant supplied onto the photosensitive drum 12 by the lubricant supply roller 16a.

The lubricant supply device 16 (lubricant supply unit) holds the solid lubricant 16b, the lubricant supply roller 16a (brush-like roller) that is in sliding contact with the photosensitive drum 12 and the solid lubricant 16b, and the solid lubricant 16b. A compression spring 16c that urges the holding member 16e toward the lubricant supply roller 16a together with the member 16e and the solid lubricant 16b is formed.
The lubricant is supplied onto the photosensitive drum 12 by the lubricant supply device 16 configured as described above. Then, the lubricant supplied onto the photosensitive drum 12 is thinned by the cleaning blade 15 disposed on the downstream side of the lubricant supply device 16.

  2 and 3, in the developing device 13, a developing roller 13a as a developer carrying member is opposed to the photosensitive drum 12 with a small gap (about 0.2 to 0.25 mm). A developing region (developing nip portion) where the photosensitive drum 12 and the magnetic brush are in contact with each other is formed at the opposite position (developing gap). A developer G (two-component developer) composed of toner T and carrier C is accommodated in the developing device 13. The developing device 13 develops the electrostatic latent image formed on the photosensitive drum 12 (forms a toner image). The configuration and operation of the developing device 13 will be described in detail later.

Referring to FIG. 1, toner cartridges 50Y, 50M, 50C, and 50BK (toner containers) contain toner T to be supplied into developing device 13 therein. Specifically, toner replenishment is performed based on information on the toner concentration (the ratio of the toner T in the developer G) detected by a magnetic sensor 13h (see FIG. 3) installed in the developing device 13. The toner T is appropriately supplied from the toner supply port 13e from the corresponding toner cartridge of the four toner cartridges 50Y, 50M, 50C, and 50BK into the developing device 13 via the apparatus.
The four toner cartridges 50Y, 50M, 50C, and 50BK are configured to be attachable to and detachable from the apparatus main body from the front side in the vertical direction (the front side in the operation direction) of the apparatus main body 1 in FIG. When the toner in the cartridge runs out, it is replaced with a new one.

Hereinafter, the developing device 13 in the image forming apparatus will be described in detail.
2 and 3, the developing device 13 includes a developing roller 13a (developer carrying member) as a rotated body, conveying screws 13b1 and 13b2 (auger screws) as conveying members, and a developer regulating member. It consists of a doctor blade 13c and the like.
An opening is formed in the developing case 13k of the developing device 13 in order to expose a part of the developing roller 13a to the photosensitive drum 12 side. In the developing roller 13a, a driven coupling 13d is installed on a shaft portion 13a20 of a sleeve 13a2 formed of a nonmagnetic material such as aluminum, stainless steel, brass, or conductive resin in a cylindrical shape. Drive is transmitted to the driven coupling 13d from the rotation driving device 60 (see FIGS. 4A and 5), and the developing roller 13a (sleeve 13a2) rotates in the clockwise direction in FIG. It is configured to be. In the sleeve 13a2 of the developing roller 13a, a magnet 13a1 that forms a plurality of magnetic poles on the peripheral surface of the sleeve 13a2 is fixed non-rotatingly (the magnet shaft is lightly press-fitted into the side plate). The developer G carried on the developing roller 13a is conveyed as the developing roller 13a (sleeve 13a2) rotates in the direction of the arrow, and reaches the position of the doctor blade 13c (developer regulating member). Then, after the developer G on the developing roller 13a is regulated to an appropriate amount (a pumping amount per unit area is about 30 to 38 mg / cm ² ) at this position, the developer G is opposed to the photosensitive drum 12 ( To the development area). The photosensitive drum is developed by an electric field formed in the developing region (a developing electric field that is a difference between the latent image potential formed on the photosensitive drum 12 and the developing bias applied to the developing roller 13a). The toner is adsorbed to the latent image formed on the surface 12.

  The doctor blade 13c as a developer regulating member is a substantially plate-like member made of a nonmagnetic material, and is disposed so as to face the upper side of the developing roller 13a. In the present embodiment, the facing distance (doctor gap) between the doctor blade 13c and the developing roller 13a is set to about 0.2 to 0.3 mm.

The developing roller 13a is rotationally driven in a predetermined direction (clockwise in FIG. 2) by a driving motor 61 as a driving source. That is, both the photosensitive drum 12 and the developing roller 13a are rotationally driven so as to move from the upper side to the lower side at the mutually opposing positions (developing gap).
In the present embodiment, two conveying screws 13b1 and 13b2 to be described later are also rotationally driven in the direction of the arrow shown in FIG. 2 by transmission of driving from the driving motor 61 (rotary driving device 60) via the gear train. .

The two conveying screws 13b1 and 13b2 (conveying members) allow the developer G accommodated in the developing device 13 to move in the longitudinal direction (the vertical direction in FIG. 2 and the left and right direction in FIG. 3), and the developing roller 13a. In the same direction as the rotation axis direction).
The first transport screw 13b1 as the first transport member is disposed at a position facing the developing roller 13a, and transports the developer G horizontally in the longitudinal direction (rotation axis direction) (see FIG. 3A). At the same time, the developer G is supplied onto the developing roller 13a at the position of the pumping magnetic pole (supply in the direction of the white arrow in FIG. 3A).

The second conveying screw 13b2 as the second conveying member is disposed at a position facing the developing roller 13a at a position below the first conveying screw 13b1. The developer G released from the developing roller 13a (the developer G released from the developing roller 13a by the agent separating magnetic pole after the developing process, which is released in the direction of the white arrow in FIG. 3B). Are transported horizontally in the longitudinal direction (the transport in the right direction indicated by the broken line arrow in FIG. 3B).
Then, the second transport screw 13b2 secondly supplies the developer G circulated from the downstream side of the transport path by the first transport screw 13b1 via the first relay portion 13g to the upstream side of the transport path by the first transport screw 13b1. It conveys via the relay part 13f (it is the conveyance shown by the dashed-dotted arrow of FIG. 3).
The two conveying screws 13b1 and 13b2 are arranged so that the rotation axis is substantially horizontal, like the developing roller 13a and the photosensitive drum 12. Moreover, as for the two conveyance screws 13b1 and 13b2, both have a screw part helically wound around the rotating shaft part.

The conveyance path (first conveyance path) by the first conveyance screw 13b1 and the conveyance path (second conveyance path) by the second conveyance screw 13b2 are isolated from each other by a wall portion.
Referring to FIG. 3, the downstream side of the transport path (second transport path) by the second transport screw 13b2 and the upstream side of the transport path (first transport path) by the first transport screw 13b1 are the second relay unit. It communicates via 13f. The developer G that has reached the downstream side of the second conveyance path by the second conveyance screw 13b2 stays in the vicinity of the second relay portion 13f and rises up, and the first conveyance screw 13b1 makes the first through the second relay portion 13f. It is transported (supplied) to the upstream side of the transport path.
In addition, the downstream side of the conveyance path by the first conveyance screw 13b1 and the upstream side of the conveyance path by the second conveyance screw 13b2 communicate with each other via the first relay portion 13g. Then, the developer G that has not been supplied onto the developing roller 13a in the first conveyance path by the first conveyance screw 13b1 falls by its own weight at the first relay portion 13g and reaches the upstream side of the second conveyance path. become.

  With such a configuration, a circulation path for circulating the developer G in the longitudinal direction in the developing device 13 is formed by the two conveying screws 13b1 and 13b2. That is, when the developing device 13 is operated, the developer G accommodated in the device flows in the direction of the broken arrow in FIG. Thus, the developer G supply path to the developing roller 13a (the first transport path by the first transport screw 13b1) and the developer G recovery path (second transport screw) separated from the developing roller 13a. 13b2), the density deviation of the toner image formed on the photosensitive drum 12 can be reduced.

2 and 3A, in the conveyance path by the first conveyance screw 13b1 (below the first conveyance screw 13b1 and at the upstream side of the first conveyance path). A magnetic sensor 13h (toner concentration detecting means) for detecting the toner concentration of the developer circulating in the apparatus is installed. Based on the toner density information detected by the magnetic sensor 13h, the toner cartridge 50 is directed into the developing device 13 through the toner supply port 13e (located in the vicinity of the second relay portion 13f). Then, new toner T is supplied.
Referring to FIG. 3, the toner replenishing port 13e is located above the upstream side of the conveyance path by the first conveyance screw 13b1 and away from the development area (outside the longitudinal range of the development roller 13a). Is).

Hereinafter, the configuration and operation of the rotation drive device 60 (image forming apparatus 1), which is characteristic in the present embodiment, will be described in detail with reference to FIGS.
The rotation driving device 60 in the present embodiment rotates the developing roller 13a as a rotated body, and is installed in the image forming apparatus main body 1.
The developing roller 13a (rotated body) is configured to be attachable to and detachable from the rotation driving device 60 in the axial direction (the horizontal direction in FIGS. 4 and 5). Specifically, the developing roller 13a is rotated and driven in conjunction with an operation in which the process cartridge 10 (developing device 13) on which the developing roller 13a is installed is attached to and detached from the image forming apparatus main body 1 in the direction perpendicular to the paper surface of FIG. It will be attached to and detached from 60.

  With reference to FIG. 4, FIG. 5, etc., in this Embodiment, the rotational drive device 60 is the drive motor 61 as a drive source, the gears 62 and 63, the drive coupling 64, the rotating shaft part 65, the intermediate member 67, A compression spring 66 and a retaining ring 78 as an urging member are configured.

The drive coupling 64 is fitted to a driven coupling 13d installed on the shaft portion 13a20 of the developing roller 13a (rotated body). As described above, the developing roller 13a is configured to be attachable to and detachable from the rotation driving device 60 (image forming apparatus 1), and thus driving transmission using the couplings 13d and 64 is useful.
Specifically, referring to FIGS. 6 to 8 in addition to FIG. 4, the drive coupling 64 and the driven coupling 13 d are respectively spaced apart in the circumferential direction at the outer circumferential portion at the tip portion in the axial direction. A plurality of claw portions 13d1, 64a are formed. Then, as shown in FIG. 4A, the claw portion 64a (convex portion) of the drive coupling 64 and the claw portion 13d1 (concave portion) of the driven coupling 13d are engaged with each other from the drive coupling 64. Drive is efficiently transmitted to the driven coupling 13d.

In the present embodiment, the driving coupling 64 and the driven coupling 13d each have a plurality of claw portions 13d1 and 64a that have tapered ends (tapered at the leading ends). ). As a result, when the developing roller 13a (process cartridge 10) is moved from the left to the right and set in the rotation driving device 60 (image forming apparatus main body 1), as shown in FIG. Even if the claw portion 64a of the coupling 64 and the claw portion 13d1 of the driven coupling 13d are not meshed with each other and the front ends collide with each other, the couplings 13d and 64 are caused by the taper shape of both ends. As shown in FIG. 4 (A), it is easy to be in a completely meshed state by rotating by the amount of play in the rotational direction.
In the present embodiment, the driven coupling 13d is fixed to the tip of the shaft portion 13a20 of the developing roller 13a by press-fitting or the like, as shown in FIG. In particular, the position of the driven coupling 13d in the shaft portion 13a20 is determined so that a part of the inner diameter portion of the driven coupling 13d becomes a space into which the distal end portion 65b of the rotating shaft portion 65 of the rotation driving device 60 is inserted. ing.

  The rotary shaft 65 is rotationally driven in the direction of the arrow in FIG. 4 together with the drive coupling 64 (and the intermediate member 67) by the drive motor 61 (drive source). Specifically, when the drive motor 61 is operated, the drive is transmitted from the first gear 62 installed on the motor shaft to the second gear 63 (installed so as to be rotatable together with the rotary shaft portion 65). The rotating shaft portion 65 is rotationally driven together with the drive coupling 64 (and the intermediate member 67) in a predetermined rotational direction.

Here, with reference to FIG. 5 (and FIGS. 6-8), in this Embodiment, when the rotating shaft part 65 is the state which the drive coupling 64 fitted to the driven coupling 13d, The tip 65b is formed so as to fit into the inner diameter of the driven coupling 13d.
That is, the tip of the rotary shaft portion 65 is interlocked with the operation in which the developing roller 13a (process cartridge 10) is moved from the left side to the right side in FIG. 5 and attached to the rotation driving device 60 (image forming apparatus main body 1). The portion 65b is inserted so as to fit into the inner diameter portion of the driven coupling 13d.
Thus, drive transmission from the rotation driving device 60 to the developing roller 13a is performed in a state where the coaxiality between the rotation shaft portion 65 of the rotation driving device 60 and the shaft portion 13a20 of the developing roller 13a is determined with high accuracy. As a result, the problem that the developing roller 13a rotates eccentrically is reduced.
In the present embodiment, as shown in FIG. 5, the rotary shaft portion 65 has a tip portion 65 b that is tapered (the tip portion 65 b is provided with a taper portion). Further, the inner diameter portion of the driven coupling 13d is formed in a tapered shape on the side facing the drive coupling 64 (provided with a tapered portion). With such a configuration, the distal end portion 65b of the rotating shaft portion 65 is driven in conjunction with the mounting operation of the developing roller 13a (process cartridge 10) to the rotation driving device 60 (image forming apparatus main body 1) as described above. The operation of fitting into the inner diameter portion of the coupling 13d is performed smoothly.

The compression spring 66 as an urging member includes a drive coupling 64 and an intermediate member 67 (installed so as to be fitted to an inner diameter portion of the drive coupling 64 as will be described later). Urging in the direction approaching (leftward in FIGS. 4 and 5).
Specifically, the compression spring (biasing member) is installed such that one end side thereof is in contact with the seat portion of the second gear 63 and the other end side thereof is in contact with the seat portion of the intermediate member 67.

With such a configuration, when the developing roller 13a (process cartridge 10) is moved from the left to the right and set in the rotation driving device 60 (image forming apparatus main body 1), as shown in FIG. Even if the claw portion 64a of the drive coupling 64 and the claw portion 13d1 of the driven coupling 13d are not meshed with each other and the tip ends collide with each other, the drive coupling 64 (and the intermediate member 67) remains. Since it slides (retracts) in the direction of the white arrow (rightward) along the rotation shaft portion 65, it is possible to prevent damage due to the collision of the couplings 13d and 64 (claw portions 13d1 and 64a).
As shown in FIG. 4B, the state in which the couplings 13d and 64 are not fitted is a state in which the drive is not transmitted from the drive coupling 64 to the driven coupling 13d as it is. However, from the state of FIG. 4B, as soon as the drive motor 61 is operated and the rotary shaft portion 65 (drive coupling 64) is driven to rotate, the circumferential direction of the drive coupling 64 (claw portion 64a). Is changed to a posture (position) fitted to the driven coupling 13d (claw portion 13d1), and the drive is transmitted from the drive coupling 64 to the driven coupling 13d (FIG. 4). (A) state).
Further, as shown in FIG. 4A, the compression spring 66 (the biasing member) is not easily released (dropped off) when both the couplings 13d and 64 are fitted. Will work. As a result, drive transmission from the drive coupling 64 to the driven coupling 13d is stably performed.

Referring to FIG. 5, in the present embodiment, the intermediate member 67 and the drive coupling 64 are axially urged by the compression spring 66 in the rotation shaft portion 65 (the movement in the left-right direction in FIG. 5). A retaining ring 68 (for example, an E-ring, a C-ring, or the like) that restricts the range is provided on the rotating shaft portion 65.
As a result, when the developing roller 13a (driven coupling 13d) is not attached to the rotation driving device (driving coupling 64), it is biased by the compression spring 66, and the intermediate member 67 and the driving coupling 64 are Can be prevented from falling off the rotating shaft portion 65.

Here, referring to FIG. 5 and the like, in the present embodiment, an intermediate member 67 is installed on the inner diameter portion of the drive coupling 64 so that the area where the drive coupling 64 contacts the rotating shaft portion 65 is reduced. ing. In particular, in the present embodiment, as shown in FIG. 9A, the intermediate member 67 is installed by press-fitting or the like into the inner diameter portion of the drive coupling 64 so that the drive coupling 64 does not contact the rotating shaft portion 65. Has been.
That is, in the present embodiment, the rotating shaft portion 65 is not directly inserted into the inner diameter portion of the drive coupling 64, but the intermediate member 67 is provided at the inner diameter portion of the drive coupling 64. The rotating shaft portion 65 is inserted into the inner diameter portion of the drive coupling 64 through the intermediate member 67.
The intermediate member 67 is configured to be movable along the drive coupling 64 along the axial direction of the rotating shaft portion 65 (the left-right direction in FIGS. 4 and 5).

Further, the intermediate member 67 is formed of a material having a smaller friction coefficient than that of the drive coupling 64.
Specifically, in the present embodiment, the drive coupling 64 is formed of a sintered metal like the driven coupling 13d, and its durability, mechanical strength, and drive transmission rigidity are enhanced. Moreover, the rotating shaft part 65 is formed with metal materials, such as stainless steel (SUS), and the durability and mechanical strength are improved.
On the other hand, the intermediate member 67 is a substantially cylindrical member having a substantially oval cross section having a seat on the side facing the compression spring 66, and has a small friction coefficient such as POM (polyacetal) and has a surface smoothness. Is made of a high resin material.

  Compared to the case where the inner diameter portion of the drive coupling 64 is brought into contact with the rotating shaft portion 65 without using the intermediate member 67, the above configuration will be described with reference to FIG. As described above, the sliding resistance generated between the drive coupling 64 and the rotary shaft 65 when the drive coupling 64 slides in the axial direction can be stably reduced over time.

In particular, in the present embodiment, the drive coupling 64 and the rotary shaft portion 65 are made of a metal material and are slid directly in order to improve the durability and mechanical strength of the apparatus. When the operation is repeated, the smoothness of the sliding surfaces is gradually lowered, and the sliding resistance of the drive coupling 64 that slides on the rotating shaft portion 65 is likely to increase. In such a case, as shown in FIG. 4B, when the driving coupling 64 does not fit into the driven coupling 13d and the front ends collide with each other, the driving coupling 64 rotates the rotation shaft. It may become difficult to move along the axial direction of the portion 65, and the couplings 13d and 64 may be damaged.
On the other hand, in the present embodiment, an intermediate member 67 made of a resin material having a small friction coefficient is interposed between the drive coupling 64 made of a metal material and the rotary shaft portion 65. The above-described problems are less likely to occur. Specifically, the member that directly contacts and slides on the rotating shaft portion 65 is the intermediate member 67, but even if these sliding operations are repeated, the smoothness of the sliding surfaces of each other decreases. Thus, the problem that the sliding resistance of the intermediate member 67 that slides on the rotating shaft portion 65 increases is less likely to occur. Therefore, as shown in FIG. 4B, when the driving coupling 64 does not fit into the driven coupling 13d and the front end portions collide with each other, the driving coupling 64 is in the axial direction of the rotary shaft portion 65. Therefore, it is difficult to cause a problem that both the couplings 13d and 64 are damaged.

  Further, referring to FIG. 5 and the like, in the present embodiment, one end side of compression spring 66 is configured not to contact the end surface of drive coupling 64 but to contact the seat portion of intermediate member 67. ing. Thereby, compared with the case where the compression spring 66 is brought into contact with the end face of the drive coupling 64, the sliding resistance generated between the compression spring 66 and the compression spring 66 can be reduced. The trouble that abnormal noise is generated by sliding with the spring 66 is reduced.

Here, as shown in FIG. 5 and FIG. 9A, in the present embodiment, the rotary shaft portion 65 has a sliding portion 65a (drive transmission) in which a cross section orthogonal to the axial direction is formed in a substantially oval shape. Part). Specifically, the rotating shaft portion 65 is formed with a parallel milling surface from the tip to a predetermined range so that the distances from the rotation center (axial center) are equal to each other.
Further, the drive coupling 64 is formed so that a cross section perpendicular to the axial direction of the inner diameter portion thereof has a substantially oval shape that is larger than the cross section of the substantially oval sliding portion 65 a in the rotation shaft portion 65. That is, the substantially oval cross-sectional shape of the inner diameter portion of the drive coupling 64 is set to be substantially similar to the substantially oval cross-sectional shape of the sliding portion 65a.
Further, the intermediate member 67 (excluding the above-described seat portion) is installed so as to be interposed between the inner diameter portion of the drive coupling 64 and the sliding portion 65a of the rotating shaft portion 65. . The intermediate member 67 is formed so as to be slidable along the axial direction in a state where the inner peripheral portion thereof is fitted to the sliding portion 65a.
The sliding portion 65a of the rotating shaft portion 65 formed in this way enables the intermediate member 67 (and the drive coupling 64) to move in the axial direction, and also allows the intermediate member 67 (and the drive coupling to move). 64) also functions to rotate together with the rotating shaft portion 65 (function to transmit driving). In particular, the sliding portion 65a (drive transmission portion) formed in a substantially oval shape is driven as compared with the case where the intermediate member (and drive coupling) is fixed to the sliding portion having a circular cross section using a parallel pin. The transmission rigidity can be increased.

In the present embodiment, as shown in FIG. 9A, the cross section of the intermediate member 67 is formed in a substantially annular shape, and the intermediate member 67 is formed over the entire outer peripheral surface of the sliding portion 65a of the rotating shaft portion 65. Configured to contact.
On the other hand, as shown in FIG. 9B, the intermediate member 67 can be formed so as to contact only the four corners of the cross section of the sliding portion 65 a in the rotating shaft portion 65. From the viewpoint of dimensional accuracy of parts, it is considered that a slight gap (backlash) is often generated between the sliding portion 65a and the intermediate member 67. In such a case, the sliding portion having a substantially oval shape is used. The drive transmission from 65a (drive transmission portion) to the intermediate member 67 (and drive coupling 64) is performed centrally at the four corners of the substantially oval sliding portion 65a. Therefore, the intermediate member 67 can be made compact by being configured so that the intermediate member 67 abuts only on the portions corresponding to the four corners of the generally oval sliding portion 65a, and the drive from the sliding portion 65a is possible. Transmission can be performed efficiently.
In the present embodiment, the entire inner diameter portion of the drive coupling 64 is configured not to contact the sliding portion 65a (rotating shaft portion 65). However, as shown in FIG. Only a part of the inner diameter portion of the ring 64 may be configured not to contact the sliding portion 65a (rotating shaft portion 65). Even in this case, the area where the drive coupling 64 contacts the rotary shaft 65 is smaller than when the entire inner diameter portion of the drive coupling 64 contacts the rotary shaft 65. Thus, the effect of reducing the problem that the drive coupling 64 is difficult to smoothly slide and move with time is exhibited.

As described above, the rotary drive device 60 according to the present embodiment is installed on the inner diameter portion of the drive coupling 64 so that the area where the drive coupling 64 contacts the rotary shaft portion 65 is small, and the drive coupling 64 64, the intermediate member 67 configured to be movable along the axial direction of the rotary shaft portion 65, the drive coupling 64, and the intermediate member 67 in a direction approaching the driven coupling 13d of the developing roller 13a (rotated body). A compression spring 66 (biasing member) for biasing is provided. The intermediate member 67 is formed of a material having a smaller friction coefficient than the drive coupling 64.
As a result, it is possible to make it difficult for the drive coupling 64 to move along the axial direction of the rotary shaft portion 65 over time.

In the present embodiment, the present invention is applied to the rotation driving device 60 that rotationally drives the developing roller 13a as the rotated body. However, the application of the present invention is not limited to this, and for example, A rotational drive device that rotationally drives the photosensitive drum 12 as a rotating body, a rotational drive device that rotationally drives the secondary transfer roller 18 as a rotated body, and a rotational drive that rotationally drives a drive roller 21 as a rotated body. Of course, the present invention can also be applied to devices.
Further, in the present embodiment, the rotary drive device 60 is configured so that the drive is indirectly transmitted from the drive motor 61 (drive source) to the rotary shaft portion 65 via the gears 62 and 63, but the drive motor ( The rotary drive device can also be configured so that the drive is directly transmitted from the drive source) to the rotary shaft portion.
And even if it is such a case, the effect similar to the thing of this Embodiment can be acquired.

  It should be noted that the present invention is not limited to the present embodiment, and it is obvious that the present embodiment can be modified as appropriate within the scope of the technical idea of the present invention, other than suggested in the present embodiment. is there. In addition, the number, position, shape, and the like of the constituent members are not limited to the present embodiment, and the number, position, shape, and the like suitable for implementing the present invention can be achieved.

1 image forming apparatus (image forming apparatus main body),
10, 10Y, 10M, 10C, 10BK process cartridge,
12 Photosensitive drum (image carrier),
13 Development device,
13a Development roller (rotated body),
13a20 shaft,
13d driven coupling,
13d1 nail part,
60 rotary drive,
61 Drive motor (drive source),
62 1st gear,
63 Second gear,
64 Drive coupling,
64a nails,
65 rotating shaft,
65a sliding part, 65b tip part,
66 compression spring (biasing member),
67 intermediate member,
68 Retaining ring.

Japanese Patent No. 4884144

Claims (9)

A rotational drive device that rotationally drives a rotated body,
A drive coupling fitted to a driven coupling installed on the shaft of the rotated body;
A rotating shaft that is rotationally driven together with the drive coupling by a drive source;
The drive coupling is installed at an inner diameter portion of the drive coupling so that an area in contact with the rotary shaft portion is small, and is configured to be movable along the axial direction of the rotary shaft portion together with the drive coupling. Intermediate members,
A biasing member that biases the drive coupling and the intermediate member in a direction approaching the driven coupling;
With
The rotary drive device according to claim 1, wherein the intermediate member is made of a material having a smaller coefficient of friction than the drive coupling.   2. The rotary drive device according to claim 1, wherein the intermediate member is installed on the inner diameter portion of the drive coupling so that the drive coupling does not contact the rotary shaft portion. The intermediate member is formed of a resin material,
The rotary drive device according to claim 1, wherein the drive coupling and the rotary shaft portion are each formed of a metal material. The rotating shaft portion includes a sliding portion in which a cross section perpendicular to the axial direction is formed in a substantially oval shape,
The drive coupling is formed so that a cross section perpendicular to the axial direction of the inner diameter portion is substantially oval than a cross section of the sliding portion of the oval shape in the rotating shaft portion,
The intermediate member is installed so as to be interposed between the inner diameter portion of the drive coupling and the sliding portion of the rotating shaft portion, and an inner peripheral portion thereof is fitted to the sliding portion. The rotary drive device according to any one of claims 1 to 3, wherein the rotary drive device is slidable along the axial direction.   The rotary drive device according to claim 4, wherein the intermediate member is formed so as to contact only four corners of a cross section of the sliding portion in the rotary shaft portion. The drive coupling and the driven coupling are respectively
A plurality of claw portions are formed on the outer peripheral portion at the tip portion in the axial direction at intervals in the circumferential direction,
The rotary drive device according to any one of claims 1 to 5, wherein tips of the plurality of claw portions are formed in a tapered shape. The rotating shaft portion is
When the drive coupling is in a state of being fitted to the driven coupling, the drive coupling is formed to be fitted to an inner diameter portion of the driven coupling,
Its tip is formed into a taper,
The rotary drive device according to any one of claims 1 to 6, wherein the inner diameter portion of the driven coupling is formed in a tapered shape on a side facing the drive coupling. The rotating body is configured to be detachable in the axial direction with respect to the rotation driving device,
The biasing member is a compression spring,
2. A retaining ring that restricts an axial range in which the intermediate member and the drive coupling are urged by the compression spring in the rotating shaft portion is provided in the rotating shaft portion. The rotation drive device according to claim 7.   An image forming apparatus comprising the rotation drive device according to claim 1 and the rotated body.

Images