JP2009092812A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus in which at least a male-side coupling or female-side coupling can be easily fitted to a driven shaft or a driving shaft and even if an angle of deviation arises between the driven shaft and the driving shaft, the coupling engaged axially movable relative to the driving shaft or the driven shaft is prevented from disengaged from the shaft. <P>SOLUTION: The female-side coupling 70 is engaged with the coupling mounting part 903 of a developing roller shaft 5a so as to be axially movable relative to a developing roller shaft 5a but immovable in its rotating direction. In addition, The axial length L1 of an engaging part 72 with the coupling mounting part 903 is made greater than the axial clearance L2 between the male-side coupling 80 and the female-side coupling 70 when the developing roller shaft 5a and a developing drive shaft 106 are connected. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an image forming apparatus such as a copying machine, a facsimile, and a printer.

In an image forming apparatus such as a copying machine, a facsimile, or a printer, a rotating body such as a drum-shaped photosensitive member, a developing roller, and a belt driving roller that drives an endless belt is generally used.
Further, a unit including a rotating body such as a process cartridge including a photosensitive member and a developing unit including a developing roller is configured to be detachable from the apparatus main body.

  In order to transmit the rotational driving force to the rotator of these detachable units, the driven shaft and the driving shaft on the apparatus main body side are aligned in a straight line in the axial direction, and the driven shaft and the driving shaft are connected by a shaft coupling. A device that is connected to transmit a rotational driving force from a drive shaft to a driven shaft is known (for example, Patent Document 1).

FIG. 26 is a cross-sectional view showing a shaft coupling having a configuration similar to that of the shaft coupling described in Patent Document 1.
As shown in FIG. 26, the shaft coupling is attached to the female-side coupling 500 attached to the shaft end of the driven shaft 210 extending from the casing (not shown) of the detachable unit, and to the shaft end of the drive shaft 310. And a male side coupling 510.
The female coupling 500 has a cylindrical portion 501 that is open at one end. In the internal space of the cylindrical portion 501, engagement convex portions 502 are formed at two locations in the circumferential direction.

  The shaft end portion of the driven shaft 210 has a mounting portion 201 having an oval cross section, and the female coupling 500 has a cylinder having an oval hole that engages with the mounting portion 201 having an oval cross section. The engaging portion 503 has a shape. Thus, the female coupling 500 is engaged with the driven shaft 210 so as to be movable in the axial direction with respect to the driven shaft 210 and not movable in the rotational direction. With this configuration, the female coupling 500 can be easily attached to the driven shaft 210, and the female coupling 500 can be easily replaced.

  The male side coupling 510 has two engagement protrusions 511 (one is not shown) extending toward the driven shaft 210 side. The male side coupling 510 has a cylindrical insertion portion 512, and the shaft end portion of the drive shaft 310 is inserted into the insertion portion 512. The insertion portion 512 of the male side coupling 510 and the shaft end portion of the drive shaft 310 are provided with through holes, respectively, and the engagement pin 301 is inserted into these through holes, so that the male side coupling. 510 is attached to the drive shaft 310.

  When a unit (not shown) is positioned and mounted on the apparatus main body, the engagement protrusions 511 of the male coupling 510 are alternately positioned with the engagement protrusions 502 in the space of the cylindrical portion 501 of the female coupling 500. And engage with the engaging projection 502. Further, when a unit (not shown) is positioned and mounted on the apparatus main body, and the driven shaft 210 and the driving shaft 310 are connected by the male side coupling 510 and the female side coupling 500, the engaging protrusion 511, the female A clearance A is formed between the bottom surface of the cylindrical portion 501 of the side coupling 500.

  The rotational driving force of the drive shaft 310 is transmitted to the male side coupling 510 via the engagement pin 301, and the driving force transmitted to the male side coupling 510 is transmitted to the female side coupling 500 via the engagement protrusion 511. Is transmitted to. Then, it is transmitted from the female coupling 500 to the driven shaft 210, the driven shaft is rotationally driven, and the rotating body of the unit rotates.

JP-A-6-332285

  In the image forming apparatus provided with the above-described shaft coupling, the unit is tilted with respect to the apparatus main body due to variations in component accuracy of the apparatus main body, or the drive shaft 310 is mounted on the apparatus main body (not shown). If it is attached to be inclined with respect to the side plate, the drive shaft 310 has a declination angle θ with respect to the driven shaft 210 as shown in FIG.

  When the driving force is transmitted in a state in which such a deviation angle θ is generated, the female-side coupling 500 and the driven shaft 210 that are engaged with the driven shaft 210 so as to be movable in the axial direction relative to the driven shaft 210. In the meantime, an axial vibration as shown by an arrow C in FIG. Due to this vibration, the female coupling 500 may move to the drive shaft 310 side. At this time, the engaging portion 503 of the female coupling 500 and the shaft mounting portion of the driven shaft 210 are more than the axial clearance (A shown in FIG. 26) between the male coupling 510 and the female coupling 500. When the axial length with respect to 201 (B shown in FIG. 26) is shorter, as shown in FIG. 27 (b), the engagement between the female coupling 500 and the driven shaft 210 is disengaged, and the driven shaft There is a problem that the driving force is not transmitted to 210.

  The present invention has been made in view of the above problems, and the object thereof is to easily assemble at least one of a male side coupling and a female side coupling to a driven shaft or a driving shaft, Even if a declination occurs between the driven shaft and the driven shaft, the coupling between the driving shaft or the coupling that is movably engaged in the axial direction with respect to the driven shaft and the shaft is not disengaged. A forming apparatus is provided.

In order to achieve the above-mentioned object, the invention of claim 1 includes a unit having a rotating body and detachable from the apparatus main body, and a driven unit provided in the unit for transmitting a driving force to the rotating body. A shaft and a drive shaft that receives a driving force from a drive source provided in the apparatus main body and is attached to one of the shaft ends of the drive shaft, and has a space in which one end is open, and an engagement convex portion in the space. And a male side coupling having a plurality of engaging projections which are attached to the other shaft end portion and are at least partially incorporated into the space of the female side coupling. A coupling, inserting the engaging protrusion of the male coupling into the space of the female coupling, and alternately positioning the engaging protrusion with the engaging protrusion. Engage with each other In the image forming apparatus that couples the driven shaft and the driving shaft, at least one of the male side coupling and the female side coupling has a shaft with respect to the driven shaft or the driving shaft. An engagement portion that engages with the driven shaft or an attachment portion provided at an end portion of the drive shaft so as to be relatively movable in the direction and relatively unmovable in the rotation direction; The axial length of the engagement portion and the engagement portion is longer than the axial clearance between the male side coupling and the female side coupling when the driven shaft and the driving shaft are connected. It is characterized by this.
According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, relative to the driven shaft or the drive shaft, the image forming apparatus is relatively movable in the axial direction and relatively unmovable in the rotational direction. The coupling engaging with the mounting portion is provided with a separation preventing member for preventing separation from the shaft.
According to a third aspect of the present invention, in the image forming apparatus according to the second aspect, when the drive shaft and the driven shaft are connected, the separation preventing member is not connected to the driven shaft or the drive shaft. The detachment preventing member is configured so as to be non-contact with the coupling engaged with the mounting portion so as to be relatively movable in the axial direction but not relatively movable in the rotational direction. It is what.
According to a fourth aspect of the present invention, in the image forming apparatus according to any one of the first to third aspects, the detachable unit is a developing unit.
According to a fifth aspect of the present invention, in the image forming apparatus according to any one of the first to fourth aspects, the detachable unit is a process cartridge.

According to the first to fifth aspects of the present invention, at least one of the male side coupling and the female side coupling is engaged with the shaft so as to be relatively movable in the axial direction with respect to the driven shaft or the driving shaft. Therefore, at least one of the male side coupling and the female side coupling can be attached to and detached from the shaft only by moving in the axial direction with respect to the driven shaft or the driving shaft. Therefore, at least one of the male side coupling and the female side coupling can be easily assembled to the driven shaft or the driving shaft.
In addition, since the axial length of the mounting portion and the engaging portion is longer than the axial clearance between the male side coupling and the female side coupling when the driven shaft and the driving shaft are connected, The following effects can be obtained. That is, a declination angle is generated between the drive shaft and the driven shaft, and vibration is generated between the driven shaft or the coupling engaged with the drive shaft so as to be movable in the axial direction relative to the drive shaft. Even if the coupling moves in a direction in which the engagement with the shaft is disengaged, the female coupling and the male coupling abut before the coupling and the shaft disengage. As a result, the coupling does not move further in the direction in which the engagement with the shaft is disengaged, and the engagement between the coupling and the shaft is not disengaged. Thereby, even if a declination angle is generated between the drive shaft and the driven shaft, the driving force of the drive shaft can be transmitted to the driven shaft.

Hereinafter, as an image forming apparatus to which the present invention is applied, an embodiment of a tandem type color laser copier (hereinafter simply referred to as “copier 600”) in which a plurality of photoconductors are arranged in parallel will be described.
FIG. 1 is a schematic configuration diagram of a copier 600 according to the present embodiment. The copying machine 600 includes a printer unit 100, a paper feeding device 200 on which the printer unit 100 is placed, a scanner 300 fixed on the printer unit 100, and the like. An automatic document feeder 400 fixed on the scanner 300 is also provided.

  The printer unit 100 includes an image forming unit including four sets of process cartridges 18Y, 18M, 18C, and 18K for forming images of each color of yellow (Y), magenta (M), cyan (C), and black (K). 20 is provided. Y, M, C, and K attached to the numbers of the respective symbols indicate members for yellow, cyan, magenta, and black (the same applies hereinafter). In addition to the process cartridges 18Y, 18M, 18C, and 18K, an optical writing unit 21, an intermediate transfer unit 17, a secondary transfer unit 22, a registration roller pair 49, a belt fixing type fixing device 25, and the like are disposed. .

The optical writing unit 21 includes a light source (not shown), a polygon mirror, an f-θ lens, a reflection mirror, and the like, and irradiates laser light onto a surface of a photoconductor described later based on image data.
The process cartridges 18Y, 18M, 18C, and 18K include a drum-shaped photosensitive member 1, a charging unit, a developing unit 4, a drum cleaning unit, a static eliminator, and the like.

Hereinafter, the yellow process cartridge 18 will be described.
The surface of the photoreceptor 1Y is uniformly charged by a charging unit as a charging means. The surface of the photoreceptor 1 </ b> Y that has been subjected to charging processing is irradiated with laser light that has been modulated and deflected by the optical writing unit 21. Thereby, the potential of the surface of the photoreceptor 1Y of the irradiation part (exposure part) is attenuated. Due to the attenuation of the surface potential, an electrostatic latent image for Y is formed on the surface of the photoreceptor 1Y. The formed electrostatic latent image for Y is developed by the developing unit 4Y as developing means to become a Y toner image.
The Y toner image formed on the Y photoconductor 1Y is primarily transferred to an intermediate transfer belt 110 described later. The surface of the photoreceptor 1Y after the primary transfer is cleaned of the transfer residual toner by the drum cleaning unit.
In the Y process cartridge 18Y, the photoconductor 1Y cleaned by the drum cleaning unit is discharged by the charge eliminator. Then, it is uniformly charged by the charging unit and returns to the initial state. The series of processes as described above is the same for the other process cartridges 18M, 18C, and 18K.

Next, the intermediate transfer unit will be described.
The intermediate transfer unit 17 includes an intermediate transfer belt 110, a belt cleaning device 90, and the like. Further, it also includes a tension roller 14, a driving roller 15, a secondary transfer backup roller 16, four primary transfer bias rollers 62Y, M, C, and K.
The intermediate transfer belt 110 is tensioned by a plurality of rollers including the tension roller 14. Then, it is endlessly moved clockwise in the drawing by the rotation of the driving roller 15 driven by a belt driving motor (not shown).
The four primary transfer bias rollers 62Y, 62M, 62C, and 62K are disposed so as to be in contact with the inner peripheral surface side of the intermediate transfer belt 110, respectively, and receive primary transfer bias from a power source (not shown). Further, the intermediate transfer belt 110 is pressed toward the photoreceptors 1Y, 1M, 1C, and 1K from the inner peripheral surface side to form primary transfer nips. In each primary transfer nip, a primary transfer electric field is formed between the photoreceptor 1 and the primary transfer bias roller 62 due to the influence of the primary transfer bias.
The above-described Y toner image formed on the Y photoconductor 1Y is primarily transferred onto the intermediate transfer belt 110 due to the influence of the primary transfer electric field and nip pressure. On the Y toner image, the M, C, K toner images formed on the M, C, K photoconductors 1M, C, K are sequentially superposed and primarily transferred. By this primary transfer of superposition, a four-color superposed toner image (hereinafter referred to as a four-color toner image) that is a multiple toner image is formed on the intermediate transfer belt 110.
The four-color toner image superimposed and transferred onto the intermediate transfer belt 110 is secondarily transferred onto a transfer sheet (not shown) as a recording medium at a secondary transfer nip described later. Transfer residual toner remaining on the surface of the intermediate transfer belt 110 after passing through the secondary transfer nip is cleaned by a belt cleaning device 90 that sandwiches the belt with the driving roller 15 on the left side in the drawing.

Next, the secondary transfer unit 22 will be described.
Below the intermediate transfer unit 17 in the figure, a secondary transfer unit 22 is provided in which a paper conveying belt 24 is stretched by two stretching rollers 23. The paper transport belt 24 is moved endlessly in the counterclockwise direction in the drawing in accordance with the rotational drive of at least one of the stretching rollers 23. One of the two stretching rollers 23 arranged on the right side in the drawing sandwiches the intermediate transfer belt 110 and the paper transport belt 24 between the secondary transfer backup roller 16 of the intermediate transfer unit 17. It is out. By this sandwiching, a secondary transfer nip is formed in which the intermediate transfer belt 110 of the intermediate transfer unit 17 and the paper transport belt 24 of the secondary transfer unit 22 are in contact with each other. A secondary transfer bias having a polarity opposite to that of the toner is applied to the one stretching roller 23 by a power source (not shown). By applying this secondary transfer bias, the four-color toner image on the intermediate transfer belt 110 of the intermediate transfer unit 17 is electrostatically moved from the belt side toward the one stretching roller 23 side in the secondary transfer nip. A next transfer electric field is formed. The transfer paper fed into the secondary transfer nip so as to synchronize with the four-color toner image on the intermediate transfer belt 110 by a registration roller pair 49 to be described later has four colors affected by the secondary transfer electric field and nip pressure. The toner image is secondarily transferred. Instead of the secondary transfer method in which the secondary transfer bias is applied to one of the stretching rollers 23 as described above, a charger for charging the transfer paper in a non-contact manner may be provided.

  In the paper feeding device 200 provided in the lower part of the copying machine 600 main body, a plurality of paper feeding cassettes 44 in which a plurality of transfer sheets can be stacked and stored in a bundle of sheets are arranged so as to overlap each other in the vertical direction. It is installed. Each paper feed cassette 44 presses the paper feed roller 42 against the uppermost transfer paper in the paper bundle. Then, by rotating the paper feed roller 42, the uppermost transfer paper is sent out toward the paper feed path 46.

  The paper feed path 46 that receives the transfer paper delivered from the paper feed cassette 44 includes a plurality of transport roller pairs 47 and a registration roller pair 49 provided near the end in the paper feed path 46. Then, the transfer paper is conveyed toward the registration roller pair 49. The transfer sheet conveyed toward the registration roller pair 49 is sandwiched between the rollers of the registration roller pair 49. On the other hand, in the intermediate transfer unit 17, the four-color toner image formed on the intermediate transfer belt 110 enters the secondary transfer nip as the belt moves endlessly. The registration roller pair 49 sends out the transfer paper sandwiched between the rollers at a timing at which the transfer paper can be brought into close contact with the four-color toner image at the secondary transfer nip. Thereby, in the secondary transfer nip, the four-color toner image on the intermediate transfer belt 110 is in close contact with the transfer paper. Then, it is secondarily transferred onto the transfer paper and becomes a full color image on the white transfer paper. The transfer paper on which the full-color image is formed in this manner exits the secondary transfer nip as the paper transport belt 24 moves endlessly, and then is sent from the paper transport belt 24 to the fixing device 25.

  The fixing device 25 includes a belt unit that moves the fixing belt 26 endlessly while being stretched by two rollers, and a pressure roller 27 that is pressed toward one roller of the belt unit. The fixing belt 26 and the pressure roller 27 are in contact with each other to form a fixing nip, and the transfer paper received from the paper transport belt 24 is sandwiched therebetween. Of the two rollers in the belt unit, the roller that is pressed from the pressure roller 27 has a heat source (not shown) inside, and heats the fixing belt 26 by the generated heat. The heated fixing belt 26 heats the transfer paper sandwiched in the fixing nip. The full color image is fixed on the transfer paper by the influence of the heating and the nip pressure.

  The transfer paper subjected to the fixing process in the fixing device 25 is stacked on the stack portion 57 provided outside the left side plate in the drawing of the printer housing, or forms a toner image on the other surface. To the secondary transfer nip described above.

  When a document (not shown) is copied, for example, a bundle of sheet documents is set on the document table 30 of the automatic document feeder 400. However, when the original is a single-sided original that is closed in a main form, it is set on the contact glass 32. Prior to this setting, the automatic document feeder 400 is opened with respect to the copying machine main body, and the contact glass 32 of the scanner 300 is exposed. Thereafter, the single-bound original is pressed by the closed automatic document feeder 400.

  When a copy start switch (not shown) is pressed after the document is set in this way, the document reading operation by the scanner 300 starts. However, when a sheet document is set on the automatic document feeder 400, the automatic document feeder 400 automatically moves the sheet document to the contact glass 32 prior to the document reading operation. In the document reading operation, first, the first traveling body 33 and the second traveling body 34 start traveling together, and light is emitted from a light source provided in the first traveling body 33. Then, the reflected light from the document surface is reflected by a mirror provided in the second traveling body 34, passes through the imaging lens 35, and then enters the reading sensor 36. The reading sensor 36 constructs image information based on the incident light.

  In parallel with such document reading operation, each device in each of the process cartridges 18Y, 18M, 18C, 18K, the intermediate transfer unit 17, the secondary transfer unit 22, and the fixing device 25 start driving. Based on the image information constructed by the reading sensor 36, the optical writing unit 21 is driven and controlled, and Y, M, C, and K toner images are formed on the respective photoreceptors 1Y, 1M, 1C, and 1K. Is done. These toner images become four-color toner images superimposed and transferred on the intermediate transfer belt 110.

  Further, almost simultaneously with the start of the document reading operation, the paper feeding operation is started in the paper feeding device 200. In this paper feeding operation, one of the paper feeding rollers 42 is selectively rotated, and the transfer paper is sent out from one of the paper feeding cassettes 44 accommodated in the paper bank 43 in multiple stages. The fed transfer sheets are separated one by one by the separation roller 45 and enter the reverse feeding path 46, and then conveyed toward the secondary transfer nip by the conveyance roller pair 47. In some cases, paper feeding from the manual feed tray 51 is performed instead of such paper feeding from the paper feeding cassette 44. In this case, after the manual feed roller 50 is selectively rotated to feed the transfer paper on the manual feed tray 51, the separation roller 52 separates the transfer paper one by one and feeds it to the manual feed path 53 of the printer unit 100. Make paper.

  In the case of forming a multicolor image composed of two or more colors of toner, the copying machine 600 stretches the intermediate transfer belt 110 so that the upper stretched surface is substantially horizontal, Photoconductors 1Y, 1M, 1C, and 1K are brought into contact with each other. On the other hand, when forming a monochrome image consisting of only K toner, the intermediate transfer belt 110 is tilted to the lower left in the drawing by a mechanism (not shown) and the upper stretched surface is set to Y, M, C. The photoconductors 1Y, 1M, and 1C are separated. Of the four photoconductors 1Y, 1M, 1C, and 1K, only the K photoconductor 1K is rotated counterclockwise in the drawing to form only the K toner image. At this time, for Y, M, and C, not only the photosensitive member 1 but also the developing unit 4 is stopped, and unnecessary members of the photosensitive member 1 and the developing unit 4 and the developer in the developing unit are unnecessarily consumed. To prevent.

  The copier 600 includes a control unit (not shown) configured by a CPU that controls each device in the copier 600, and an operation display unit (not shown) configured by a liquid crystal display, various key buttons, and the like. . The operator sends a command to the control unit by a key input operation on the operation display unit, so that one of the three modes is selected from the three-sided print mode, which is a mode for forming an image only on one side of the transfer paper. You can choose one. The three single-sided printing modes include a direct discharge mode, a reverse discharge mode, and a reverse decal discharge mode.

  FIG. 2 is an enlarged configuration diagram showing the developing unit 4 and the photosensitive member 1 included in one of the four process cartridges 18Y, 18M, 18C, and 18K. Since the four process cartridges 18Y, 18M, 18C, and 18K have substantially the same configuration except that the colors of the toners to be handled are different, the subscripts Y, M, C, and K added to “4” in FIG. Is omitted.

The developing unit 4 has a developing roller 5 as a developer carrying member for supplying toner to the latent image on the surface of the photoreceptor 1 while moving the surface in the direction of arrow I in the drawing. The developing roller 5 includes a rotatable developing sleeve, and a magnetic body (not shown) including a plurality of magnetic poles is disposed therein. The magnetic material is necessary for holding the developer on the surface of the developing roller 5.
Further, a supply screw 8 is provided as a supply conveyance member that conveys the developer in the depth direction of FIG. 2 along the axial direction of the development roller 5 while supplying the developer to the development roller 5.
A doctor blade 12 as a developer regulating means for regulating the developer supplied to the developing roller 5 to a thickness suitable for development is provided on the downstream side in the surface movement direction from the portion facing the supply screw 8 of the developing roller 5. ing.
A collection conveyance path 7 that collects the developed developer that has passed through the developing area and separated from the surface of the developing roller 5 on the downstream side in the surface movement direction from the developing area that is the portion of the developing roller 5 facing the photoreceptor 1. Faces the developing roller 5. The collection conveyance path 7 is a collection conveyance member that conveys the collected developer collected in the same direction as the supply screw 8 along the axial direction of the developing roller 5, and a spiral collection screw 6 that is arranged parallel to the axial direction. I have. A supply / conveyance path 9 provided with the supply screw 8 is provided side by side in the lateral direction of the developing roller 5, and a recovery / conveyance path 7 provided with the recovery screw 6 is provided below the developing roller 5.

  The developing unit 4 is provided with a stirring conveyance path 10 in parallel with the collection conveyance path 7 below the supply conveyance path 9. The agitating / conveying path 10 is disposed in parallel to the axial direction as an agitating / conveying member that conveys the developer along the axial direction of the developing roller 5 to the front side in the figure, which is opposite to the supply screw 8 while stirring the developer. A helical stirring screw 11 is provided.

The supply conveyance path 9 and the stirring conveyance path 10 are partitioned by a first partition wall 133 as a partition wall. In the first partition wall 133, the supply conveyance path 9 and the agitation conveyance path 10 are partitioned at both ends on the front side and the back side in the drawing, and the supply conveyance path 9 and the agitation conveyance path 10 communicate with each other. is doing.
The supply conveyance path 9 and the recovery conveyance path 7 are both partitioned by the first partition wall 133, but an opening is provided at a location where the supply conveyance path 9 and the recovery conveyance path 7 of the first partition wall 133 are partitioned. Absent.
In addition, the two developer conveyance paths of the agitation conveyance path 10 and the recovery conveyance path 7 are partitioned by a second partition wall 134 as a partition member. The second partition wall 134 has an opening on the front side in the figure, and the agitation transport path 10 and the collection transport path 7 communicate with each other.

  The developer thinned by the doctor blade 12 made of stainless steel on the developing roller 5 is transported to a developing area which is a portion facing the photosensitive member 1 for development. The developer after the development is collected in the collection conveyance path 7, conveyed to the front side of the cross section in FIG. 2, and to the agitation conveyance path 10 through the opening of the first partition wall 133 provided in the non-image area portion. Developer is transferred. The toner is supplied to the stirring and conveying path 10 from a toner replenishing port 950 (described later) provided on the upper side of the stirring and conveying path 10 near the opening of the first partition wall 133 on the upstream side in the developer conveying direction in the stirring and conveying path 10. Supplied.

FIG. 3 is a perspective view of the developing unit 4 as viewed from the driving side.
As shown in the figure, the shaft end portion of the developing roller shaft 5 a that is a driven shaft for transmitting a driving force to the developing roller 5 that is a rotating body protrudes from the casing of the developing unit 4. The shaft end of the developing roller 5 has an oval coupling attachment portion 903 having a width W and a diameter D as shown in FIG. Further, the shaft end portion of the supply screw 8 also protrudes from the casing of the developing unit 4, and a coupling gear 8a is attached to the shaft end portion. An idler gear (not shown) is engaged with the coupling gear 8a, and a driving force is transmitted from the idler gear to the recovery screw 6 and the stirring screw 11.
A toner supply port 950 for supplying toner from a toner supply device (not shown) is provided on the side opposite to the drive side.

  As shown in FIG. 5, after the development unit 4 is temporarily positioned on the frame of the process cartridge 18, as shown in FIG. 6, the positioning plate is placed on the surface opposite to the drive side of the frame of the process cartridge 18, respectively. 905 is attached and positioned. The photoreceptor 1 and the developing roller 5 are correctly positioned by the positioning plate 905, and the process cartridge 18 in which the photoreceptor 1 and the developing unit 4 are integrated is configured. In addition, the distance between the central axis of the photoreceptor 1 and the central axis of the developing roller 5 is correctly regulated by the positioning plate 905. As a result, when the photosensitive member 1 and the developing roller 5 are arranged to face each other with a minute gap, the gap is correctly maintained, and a high-quality toner image is developed on the photosensitive member 1. be able to. Further, when the photosensitive member 1 and the developing roller 5 are configured to contact each other and face each other, the contact pressure is correctly regulated, and a high-quality toner image is developed on the photosensitive member 1. Can do.

  As shown in FIG. 6, when the positioning plate 905 is attached, the coupling attachment portion 903 provided at the shaft end portion of the developing roller shaft 5 a is located deeper than the positioning plate 905. Then, as shown in FIG. 7, the female coupling 70 is attached to the coupling attachment portion 903.

FIG. 8 is a perspective view of the main body driving apparatus 900.
The main body driving apparatus 900 is attached to a back side plate (not shown) of the apparatus main body.
A cleaning motor 92, a developing motor 91, and a photoconductor motor (not shown) are attached to the first holding plate 95 of the main body driving device 900. A cleaning idler gear 93 is engaged with the motor gear 92 a of the cleaning motor 92, and the cleaning idler gear 93 is fixed to a rotating shaft 93 a supported by the first holding plate 95 and the second holding plate 98. The cleaning idler gear 93 meshes with a cleaning gear 94 fixed to the cleaning drive shaft. The cleaning drive shaft is rotatably supported by the first holding plate 95 and the second holding plate 98 via a bearing 120. The process cartridge side shaft end of the cleaning drive shaft protrudes from the second holding plate 98, and the cleaning coupling 102 is attached to the shaft end so as to be movable in the axial direction. The cleaning coupling 102 is biased toward the process cartridge 18 by a coil spring 101 wound around the cleaning drive shaft.

A developing idler gear 96 is engaged with the motor gear 91a of the developing motor 91. The development idler gear 96 is fixed to a rotating shaft 96 a supported by the first holding plate 95 and the third holding plate 109. The first pulley 107 is fixed to the rotary shaft 96a. A timing belt 97 is wound around the first pulley 107, and the timing belt 97 is fixed to a developing drive shaft 106 that is rotatably supported by a second holding plate 98 via a bearing 103. It is also wound around a third pulley (not shown) fixed to a screw drive shaft rotatably supported by two pulleys 99, first and second holding plates 95, 98 via bearings 104.
A process cartridge side shaft end of the screw drive shaft protrudes from the second holding plate 98, and a screw coupling 105 is attached to the side shaft end so as to be movable in the axial direction. The screw coupling 105 is urged toward the process cartridge by a coil spring 108 wound around the screw drive shaft.
A male side coupling 80 to be described later is fixed to the process cartridge side shaft end portion of the development drive shaft 106.

  A photoconductor shaft (not shown) integral with a photoconductor motor (not shown) passes through the hole 111 provided below the first holding plate 95.

  In the process cartridge 18, a photosensitive member shaft (not shown) is inserted into a through hole provided on the flange of the photosensitive member, and a convex gear (not shown) provided on the photosensitive member shaft is provided on the driving side flange of the photosensitive member. The process cartridge 18 is positioned by meshing with the concave gear (112 shown in FIG. 5). Further, as shown in FIG. 9, when the process cartridge 18 is mounted on the apparatus main body, the cleaning coupling 102 (not shown) is fixed to the drive shaft side end of the rotating shaft of the cleaner recovery screw of the cleaning unit. Engage coupling. As a result, the driving force of the cleaning motor 92 is transmitted to the cleaning idler gear 93, the cleaning gear 94, and the cleaning coupling 102, and the cleaner recovery screw rotates.

  Further, the screw coupling 105 is engaged with the coupling gear 8a attached to the shaft end portion of the supply screw shown in FIG. Thereby, the rotational driving force of the developing motor 91 is transmitted through the screw coupling 8a, and the supply screw 8, the stirring screw 11, and the recovery screw 6 are rotationally driven.

  Further, the male side coupling 80 is engaged with the female side coupling 70 shown in FIG. Thereby, the rotational driving force of the developing motor 91 is transmitted through the male coupling 80, and the developing roller 5 is rotationally driven.

  In the present embodiment, the driving force for rotationally driving the supply screw 8, the recovery screw 6, and the stirring screw 11 and the driving force for rotationally driving the developing roller 5 are transmitted from separate drive shafts. is doing. With such a configuration, the developing roller shaft 5a is geared to the developing roller 5 as compared with the one that transmits the driving force for rotationally driving the supply screw 8, the collecting screw 6, and the stirring screw 11 through the gear. It is possible to suppress the propagation of the vibration of the drive transmission mechanism such as. Thereby, it is possible to suppress the occurrence of image formation abnormalities such as band-like pitch unevenness (banding, jitter), density unevenness, and horizontal stripe-like background stains in the formed image.

Next, features of the present embodiment will be described.
FIG. 10 is a cross-sectional view of the main part showing a state in which the female side coupling 70 and the male side coupling 80 are engaged. 11 is a perspective view of the female side coupling 70 viewed from the engaging portion 72 side, and FIG. 12 is a perspective view of the female side coupling 70 viewed from the opening end 71a side of the cylindrical portion 71. is there. Also, FIG. 4 is a side view of the male side coupling 80. FIG.

  As shown in FIGS. 11 and 12, the female side coupling 70 includes a cylindrical portion 71 into which the male side coupling 80 is inserted from an opening provided on one end side in the axial direction. From the other end side of the cylindrical portion 71, an engagement portion 72 having an oblong hole 72 a having a width W ′ and a diameter D ′, which is a cross-sectional shape cut in a direction orthogonal to the axial direction, is provided. The width W ′ and diameter D ′ of the hole 72a of the engaging portion 72 are set to be equal to or slightly larger than the width W and diameter D of the coupling mounting portion 903 of the developing roller shaft 5a. Accordingly, the female side coupling 70 can be easily moved in the axial direction with respect to the coupling mounting portion 903 of the developing roller shaft 5a, and the female side coupling 70 can be easily coupled without using a tool or the like. It can be detached from the attachment portion 903. In addition, the coupling attachment portion 903 is formed in a non-circular shape with an oval shape, and the hole shape of the engagement portion 72 is also the same shape, so that the coupling attachment portion 903 inserted into the hole 72a of the engagement portion 72 is in the hole. Thus, the rotational driving force of the female coupling 70 is transmitted to the developing roller shaft 5a without idling. In the above description, the cross-sectional shape of the coupling attachment portion 903 and the shape of the hole 72a of the engagement portion 72 are oval shapes, but may be non-circular such as a D-shape or a square shape.

  In the present embodiment, as shown in FIG. 10, the drive shaft side end of the developing roller shaft 5 a is not protruded from the positioning plate 905, and is located deeper than the positioning plate 905. Thus, by positioning the end of the developing roller shaft 5a on the drive shaft side at a position deeper than the positioning plate 905, the process cartridge 18 and the main body drive device 900 when the process cartridge 18 is attached to the main body of the apparatus are arranged. The gap between them can be narrowed, and the copying machine 600 can be downsized in the axial direction.

However, when the driving side shaft end portion of the developing roller shaft 5a is positioned at a position deeper than the positioning plate 905 in this way, the female side coupling 70 is fixed to the developing roller shaft by a fixing means such as a screw as in the prior art. If it is fixed so that it cannot move in the axial direction and the rotational direction with respect to 5a, when replacing the female coupling 70, the positioning plate 905 is removed and the fixing means such as a screw is removed and replaced. Therefore, the workability of replacing the female coupling 70 is deteriorated.
On the other hand, as in this embodiment, the shape of the hole 72a of the coupling attachment portion 903 and the engagement portion 72 is made non-circular, and the female side coupling 70 is movable in the axial direction with respect to the developing roller shaft 5a. By engaging with the rotational direction so as not to move, the female side coupling 70 can be exchanged only by moving the female side coupling in the axial direction without removing the positioning plate 905. Can be improved. Further, since no fixing means such as a screw is used, the number of parts can be reduced and the apparatus can be made inexpensive.

  Further, as shown in FIG. 12, the space 73 of the tubular portion 71 of the female side coupling extends in the axial direction from the bottom 73a and is engaged in the circumferential direction with a phase difference of about 180 [°]. A convex portion 74 is provided. Each engaging convex portion 74 has an inclined surface 74a and a wall surface 74b. Further, a tapered surface 75 whose diameter increases toward the opening end 71a is formed on the opening end 71a side of the cylindrical portion 71.

  As shown in FIG. 13, in the male side coupling 80, the engaging claws 82, which are engaging protrusions protruding from the pedestal portion 85 toward the female side coupling 70, have a phase difference of about 180 [°]. Is formed. One side surface of the engaging claw 82 is a tapered surface 82a, and the other surface is a wall surface 82b. A cylindrical mounting portion 81 is provided on the drive side of the pedestal portion 85, and a through hole 84 is formed in the cylindrical mounting portion 81.

  As shown in FIG. 10, the process cartridge side shaft end portion of the developing drive shaft 106 is inserted into the cylindrical mounting portion 81. Then, the engaging pin 83 is fitted in a state where the through-hole penetrating in the direction orthogonal to the axial direction provided at the shaft end portion of the developing drive shaft 106 and the through-hole 84 of the mounting portion 81 are positioned in a straight line. As a result, the male side coupling 80 is fixed to the developing drive shaft 106.

  As shown in FIG. 10, since the development drive shaft 106 is supported only by the second holding plate 98, the shaft end portion of the development drive shaft 106 is movable in the radial direction.

  In the present embodiment, since the process cartridge 18 is positioned by a photosensitive member shaft (not shown), even if the process cartridge 18 is correctly positioned with respect to the apparatus main body, the axial center of the developing roller shaft 5a is accumulated by the accumulation of tolerances. And the axial center of the development drive shaft 106 may deviate in the radial direction. As described above, when the engaging claw 82 of the male coupling 80 is to be inserted into the cylindrical portion of the female coupling 70 in a state in which the axial misalignment has occurred, the tip of the engaging claw 82 becomes the cylindrical portion 71. It hits against the open end 71a. When the engaging claw 82 is further inserted into the cylindrical portion from the state of being struck in this manner, the developing drive shaft 106 is tilted around the fitting portion with the bearing 103, and the engaging claw 82 is in the cylindrical portion. Can be inserted. At this time, since the tip of the engaging claw 82 is guided by the tapered surface 75 of the opening end 71a, the engaging claw 82 can be inserted into the cylindrical portion more smoothly.

  Further, since the driving force is transmitted to the developing drive shaft 106 via the timing belt 97, even if the developing drive shaft 106 is inclined and the position of the second pulley 99 fluctuates as shown in FIG. The timing belt 97 absorbs the fluctuation. As a result, the driving force can be transmitted to the developing drive shaft 106 well, and damage to the member upstream of the developing drive shaft 106 in the driving transmission direction can be prevented.

  Further, when the engaging claw 82 is inserted into the cylindrical portion, the tip of the engaging claw 82 is engaged with the engaging convex portion 74 if the phases of the engaging claw 82 and the engaging convex portion 74 in the cylindrical portion are matched. In that case, the inclined surface 82 a of the engaging claw 82 is guided by the inclined surface 74 a of the engaging convex portion 74, so that the female side coupling 70 is relative to the male side coupling 80. Rotate to. Accordingly, the engaging claws 82 can be alternately positioned with the engaging convex portions 74, and the developing drive shaft 106 and the developing roller shaft 5a can be connected. When the development drive shaft 106 is driven to rotate, the wall surface 82b of the engagement claw 82 abuts against the wall surface 74b of the engagement projection 74, whereby the female side coupling 70 and the male side coupling 80 are engaged, and development drive is performed. The rotational driving force of the shaft 106 can be transmitted to the developing roller shaft 5a.

  Further, as shown in FIG. 15, the development drive shaft 106 may be rotatably and elastically held on the first holding plate 95 via a bearing 130 and an elastic member 131. As the elastic member 131, a flexible member such as a coil spring, a leaf spring, rubber or sponge can be used. In this case, when there is a misalignment between the developing roller shaft 5a and the developing drive shaft 106, the elastic member 131 is elastically deformed, so that the developing drive shaft 106 is inclined, and the male coupling 80 and the female cup are connected. The ring 70 can be engaged.

By the way, as described above, there is an axial misalignment between the developing roller shaft 5a and the developing drive shaft 106, and the developing drive shaft 106 is inclined so that the male side coupling 80 and the female side coupling 70 are engaged. When the main body driving device 900 is attached to the side plate of the copying machine main body with an inclination, a deviation angle θ is generated between the developing roller shaft 5a and the developing driving shaft 106. When drive transmission is performed in such a state, the female side coupling 70 attached to the developing roller shaft 5a so as to be movable in the axial direction may vibrate in the axial direction with respect to the developing roller shaft 5a. When such vibration occurs, the female side coupling 70 may move toward the developing drive shaft.
In the present embodiment, as shown in FIG. 10, the axial length L1 of the coupling attachment portion 903 and the engagement portion 72 is engaged with the female side coupling 70 and the male side coupling 80. It is longer than the axial clearance L2 between the female coupling 70 and the male coupling 80 when the developing roller shaft 5a and the developing drive shaft 106 are connected. Therefore, as shown in FIG. 16, the female coupling 70 abuts the male coupling 80 before the coupling attachment portion 903 and the engagement portion 72 are disengaged. As a result, since the female side coupling 70 cannot move further to the development drive shaft 106 side, the coupling attachment portion 903 and the engagement portion 72 are not disengaged. Therefore, even if the deviation angle θ occurs between the developing roller shaft 5a and the developing drive shaft 106, the driving force of the developing drive shaft 106 can be transmitted to the developing roller shaft 5a.

  As described above, when there is an angle θ between the developing roller shaft 5 a and the developing drive shaft 106, the engaging claw 82 of the male side coupling 80 is connected to the inside of the cylindrical portion 71 of the female side coupling 70. It strongly contacts the peripheral surface, and the engagement force between the male side coupling 80 and the female side coupling 70 increases. As a result, as shown in FIG. 17, when the process cartridge 18 is removed from the copying machine 600, the female side coupling 70 is engaged with the developing roller shaft 5a and is not taken out from the apparatus main body together with the process cartridge 18; There was a problem that the coupling 70 remained in the apparatus main body.

Therefore, in the present embodiment, as shown in FIG. 18, a separation preventing member 906 that prevents the female coupling 70 from separating from the developing roller shaft 5a is provided on the positioning plate 905 of the process cartridge 18.
The separation preventing member 906 includes an attachment portion 906a for attaching to the positioning plate 905, an arm portion 906b extending in the axial direction, and a pressing portion 906c. The separation preventing member 906 is formed by bending a metal sheet metal to form the attachment portion 906a, the arm portion 906b, and the pressing portion 906c.
A screw hole 906d is formed in the mounting portion 906a. By inserting a screw into the screw hole 906d and screwing the screw into the screw hole for attaching the separation preventing member provided on the positioning plate 905, the screw detachment is achieved. The prevention member 906 is fixed to the positioning plate 905.
The arm portion 906b extends in parallel with a certain gap between the arm portion 906b and the cylindrical portion 71 of the female side coupling 70, thereby making the female side coupling 70 and the arm portion 906b non-contact. Thereby, it is possible to prevent the female side coupling 70 from sliding with the arm portion 906b during driving transmission, and it is possible to prevent generation of abnormal noise and wear of the female side coupling.
The pressing portion 906c is formed by bending the distal end of the developing drive shaft side of the arm portion 906b toward the female coupling 70, and is configured to face only the opening end 71a of the female coupling 70.
Further, as shown in FIG. 19, when the female side coupling 70 moves by vibration and hits the male side coupling 80, between the pressing portion 906 c and the opening end 71 a of the female side coupling 70. The axial length of the arm portion 906b is set so that a gap is formed. Thereby, it is possible to prevent the female side coupling 70 from sliding with the separation preventing member 906 during drive transmission, and it is possible to prevent the generation of abnormal noise and the wear of the female side coupling 70.

  By providing the separation preventing member 906, when the process cartridge 18 is removed from the copying machine 600, the engagement force between the female side coupling 70 and the male side coupling 80 is large, and the female side coupling 70 is coupled with the process cartridge 18. When not moved, the pressing portion 906 c of the separation preventing member 906 comes into contact with the opening end 71 a of the female side coupling 70. Then, the female side coupling 70 is moved in the removal direction by the pressing portion 906c of the separation preventing member 906, and the engagement between the male side coupling 80 and the female side coupling 70 is released, as shown in FIG. The female side coupling 70 can be taken out from the copying machine 600 together with the process cartridge 18 without detaching from the developing roller shaft 5a.

  In the above description, the female-side coupling 70 is attached to the developing roller shaft 5a so as to be movable in the axial direction with respect to the developing roller shaft, but cannot be moved in the rotational direction. The coupling may be a male side coupling 80. In the above description, the male side coupling 80 is attached to the developing drive shaft 106 so as not to rotate and move in the axial direction by using the engaging pin 83. However, the female side coupling 70 and the developing roller shaft 5a are attached. In the same manner as the above, the male coupling 80 may be attached to the developing drive shaft 106 so as to be movable in the axial direction. In this case, since the male side coupling 80 moves in the axial direction and the male side coupling 80 and the development drive shaft 106 may be disengaged, the male side coupling 80 and the development drive shaft 106 Even if the male side coupling 80 moves in the axial direction at the time of driving transmission, the male side cup is formed so that the length in the axial direction of the mounting portion is longer than the clearance between the female side coupling 70 and the male side coupling 80. The engagement between the ring 80 and the development drive shaft 106 is prevented from being disengaged. Further, when the process cartridge 18 is removed, the above-described separation preventing member 906 is attached to the main body driving device in order to prevent the male side coupling 80 from being detached from the developing drive shaft 106 and removed from the main body together with the process cartridge 18. It is attached to the second holding plate 98 of 900. Accordingly, when the male coupling 80 is engaged with the female coupling 70 and is about to be removed from the main body together with the process cartridge 18, the separation preventing member 906 moves the male coupling 80. Can be stopped and can remain in the apparatus body.

In the above description, the connection between the developing roller shaft 5a of the developing unit 4 attached to and detached from the apparatus main body and the developing drive shaft 106 as the process cartridge 18 has been described. However, the developing unit attached and detached from the apparatus main body alone. The present invention can also be applied to the connection between the four developing roller shafts 5a and the developing drive shaft 106.
In this case, as shown in FIG. 21, a guide rail 907a for the process cartridge 18 provided with the cleaning device and the photosensitive member 1 and a guide rail 907b for the developing unit 4 are formed in the apparatus main body, respectively. A guide groove (not shown) of the cartridge 18 is fitted into the process cartridge guide rail 907a, and the process cartridge 18 is inserted into the apparatus main body along the guide rail 907a. Further, a guide groove (not shown) of the developing unit 4 is fitted into the developing unit guide rail 907b, and the developing unit 4 is inserted into the apparatus main body along the guide rail 907b. Further, as shown in FIG. 22, by setting the developing unit 4 and the process cartridge 18 in the drawer unit 908 slidably attached to the apparatus main body, and pushing the drawer unit 908 into the apparatus main body, The process cartridge 18 and the developing unit 4 may be inserted into the apparatus main body.

  In the above description, the example in which the present invention is applied to the connection between the development roller shaft 5a of the development roller 5 of the development unit 4 and the development drive shaft 106 has been described. However, the connection between the screw drive shaft and the supply screw shaft, The present invention can also be applied to the connection between the cleaner recovery screw and the cleaning drive shaft. Further, the present invention can be applied not only to the process cartridge 18 and the developing unit 4 but also to a fixing unit that can be attached to and detached from the apparatus main body, an intermediate transfer unit, and a secondary transfer unit.

The present invention is not limited to an intermediate transfer tandem color image forming apparatus.
For example, as shown in FIG. 23, the present invention can also be applied to a direct transfer tandem color image forming apparatus. Further, as shown in FIG. 24, the present invention is also applied to a color image forming apparatus using a drum-shaped intermediate transfer member 110 ′ instead of the intermediate transfer belt 110 in the electrophotographic color image forming apparatus of the intermediate transfer tandem method. can do. Further, as shown in FIG. 25, one process cartridge 18 as described above is provided, and an image is formed on the photosensitive member 1 of the process cartridge 18, and the image is transferred by a transfer roller 50 to form an image on a recording material. The present invention can also be applied to a direct transfer type monochrome image forming apparatus for recording.

As described above, according to the image forming apparatus of the present embodiment, the developing roller 5 that is a rotating body has a process cartridge 18 that is a unit that can be attached to and detached from the apparatus main body, and the driving force applied to the developing roller 5 provided in the process cartridge 18. A female knife is attached to the shaft end of the developing roller shaft 5a, which is a driven shaft for transmitting the rotation, and has a space in which one end is open, and a plurality of engaging projections 74 are formed in the space at equal intervals in the circumferential direction. The side coupling 70 is attached to a shaft end portion of a development drive shaft 106 that is a drive shaft that is driven to rotate by receiving a driving force from a development motor 91 that is a drive source provided in the apparatus body, and at least a part of the side coupling 70 is a female side coupling And a male side coupling 80 having a plurality of engaging claws 82 which are a plurality of engaging protrusions incorporated in the space 70. Further, the engaging claw 82 of the male coupling 80 is inserted into the space of the female coupling 70, and the engaging claw 82 is alternately positioned with the engaging convex portion 74 to engage with the engaging convex portion 74. By doing so, the development roller shaft 5a and the development drive shaft 106 are connected. The female coupling 70 is provided at the shaft end of the developing roller shaft 5a so that it can move relative to the developing roller shaft 5a in the axial direction but cannot move in the rotational direction. An engagement portion 72 that engages with a coupling attachment portion 903 as an attachment portion is provided.
With this configuration, the female coupling 70 can be attached to and detached from the developing roller shaft 5a only by moving the female coupling 70 in the axial direction with respect to the developing roller shaft 5a. Therefore, the female coupling 70 can be easily assembled to the developing roller shaft 5a.
Further, in the image forming apparatus of the present embodiment, the male side coupling 80 when the developing roller shaft 5a and the developing drive shaft 106 are connected is set to the axial length of the coupling mounting portion 903 and the engaging portion 72. And the axial clearance between the female coupling 70 and the female side coupling 70. With this configuration, a declination angle is generated between the developing drive shaft 106 and the developing roller shaft 5a, and vibration is generated between the female side coupling 70 and the developing roller shaft 5a. Even if the engagement with the developing roller shaft 5a is disengaged, the female coupling 70 and the male coupling 80 abut before the female coupling 70 and the developing roller shaft 5a are disengaged. . As a result, the knife-side coupling 70 does not move further in the direction in which the engagement with the developing roller shaft 5a is released, and the engagement between the knife-side coupling 70 and the developing roller shaft 5a is not released. Thereby, even if a declination is generated between the developing roller shaft 5a and the developing drive shaft 106, the driving force of the developing drive shaft 106 can be transmitted to the developing roller shaft 5a.

  In addition, the image forming apparatus according to the present embodiment has a female side engaged with the coupling mounting portion 903 so as to be relatively movable in the axial direction but not relatively movable in the rotational direction with respect to the developing roller shaft 5a. The coupling 70 includes a separation preventing member 906 that prevents the coupling 70 from separating from the developing roller shaft 5a. This prevents the knife-side coupling from being detached from the developing roller shaft 5a, and prevents the knife-side coupling from being detached from the developing roller shaft and staying in the apparatus main body.

  In addition, when the developing roller shaft 5a and the development driving shaft 106 are connected, the separation preventing member 906 is configured to be in non-contact with the female coupling 70 so that the female side cup is configured. The ring does not slide with the separation preventing member, and it is possible to prevent generation of abnormal noise and wear of the female side coupling.

  In addition, since the developing unit is configured to be detachable from the apparatus main body, the developing unit can be easily replaced.

  Further, by using a process cartridge, the photosensitive member and the developing unit can be replaced as a unit.

1 is a schematic configuration diagram of a copier according to an embodiment. FIG. 2 is a schematic configuration diagram of a developing unit and a photoreceptor. The perspective view which looked at the developing unit from the drive side. FIG. 3 is an enlarged perspective view of a driving side end of a developing roller shaft. FIG. 4 is a diagram illustrating a state where a development unit is temporarily positioned on a process cartridge. The figure which shows the process cartridge which attached the positioning plate. The figure which shows the process cartridge which attached the female side coupling to the developing roller shaft. The perspective view of a main body drive device. FIG. 3 is a diagram showing a state when a process cartridge is mounted on a copying machine. The principal part sectional drawing which shows the engagement state of a female side coupling and a male side coupling. The perspective view which looked at the female side coupling from the engaging part side. The perspective view which looked at the female side coupling from the opening end side. The side view of a male side coupling. The figure explaining a mode that the position of a 2nd drive pulley fluctuates, when a declination angle arises in a development drive shaft. The figure which shows another support form of a development drive shaft. The principal part sectional drawing which shows the engagement state of a female side coupling and a male side coupling when a declination arises in a developing drive shaft and a developing roller. The figure which shows a mode that a female side coupling is left in a main body and a process cartridge is removed from a main body. FIG. 3 is a perspective view of a main part of a process cartridge provided with a separation preventing member. The figure explaining the positional relationship of a female side coupling and a detachment preventing member when a declination occurs between the development drive shaft and the development roller. The figure which shows a mode that the process cartridge provided with the detachment | leave prevention member is removed from a main body. FIG. 3 is a diagram for explaining an example of a configuration of a copying machine for mounting a process cartridge and a developing unit to an apparatus main body. FIG. 6 is a diagram for explaining another example of a configuration of a copying machine for mounting a process cartridge and a developing unit to an apparatus main body. The figure which shows the tandem type color image forming apparatus of a direct transfer system. 1 is a diagram illustrating an intermediate transfer type tandem color image forming apparatus using an intermediate transfer drum. FIG. The figure which shows a monochrome image forming apparatus. Sectional drawing which shows the structure of the conventional shaft coupling. The figure explaining the behavior of a female side coupling when a declination arises in a driven shaft and a drive shaft.

Explanation of symbols

70: Female side coupling 72: Engagement part 74: Engagement convex part 80: Male side coupling 82: Engagement claw 91: Development motor 106: Development drive shaft 600: Copying machine 903: Coupling attachment part 905: Positioning Plate 906: Detachment preventing member 908: Drawer unit

Claims (5)

A unit having a rotating body and detachable from the apparatus body;
Attached to one of the shaft ends of a driven shaft provided in the unit for transmitting a driving force to the rotating body and a driving shaft that rotates by receiving a driving force from a driving source provided in the apparatus main body. A female side coupling having a space where one end is open, and a plurality of engaging projections formed in the space at equal intervals in the circumferential direction;
A male coupling having a plurality of engaging protrusions attached to the other shaft end and at least a part of which is incorporated into the space of the female coupling;
The engagement protrusion of the male coupling is inserted into the space of the female coupling, and the engagement protrusion is alternately positioned with the engagement protrusion to engage with the engagement protrusion. Thus, in the image forming apparatus for connecting the driven shaft and the driving shaft,
The at least one of the male side coupling and the female side coupling can move relative to the driven shaft or the driving shaft in the axial direction and relatively unmovable in the rotational direction. An engaging portion that engages with a driven shaft or a mounting portion provided at a shaft end of the driving shaft;
The axial length of the mounting portion and the engaging portion is greater than the axial clearance between the male coupling and the female coupling when the driven shaft and the driving shaft are connected. An image forming apparatus characterized by being made longer. The image forming apparatus according to claim 1.
A coupling that engages with the mounting portion is disengaged from the shaft, and is movable relative to the driven shaft or the drive shaft in the axial direction but not relatively movable in the rotational direction. An image forming apparatus, comprising: a separation preventing member for preventing the separation. The image forming apparatus according to claim 2.
When the drive shaft and the driven shaft are connected, the separation preventing member can move relative to the driven shaft or the drive shaft in the axial direction and relatively in the rotational direction. An image forming apparatus, wherein the separation preventing member is configured so as to be non-movable and in non-contact with a coupling engaged with the attachment portion. The image forming apparatus according to claim 1,
The image forming apparatus, wherein the detachable unit is a developing unit. The image forming apparatus according to claim 1,
The image forming apparatus, wherein the detachable unit is a process cartridge.

Images