JP2022030009A - Rotation mechanism, transfer device, and image forming apparatus - Google Patents

Abstract

To allow a rotation member to easily relatively move in an axial direction with respect to the support shaft even when the outer diameter of the support shaft is not uniform over the axial direction.SOLUTION: A rotation mechanism comprises: a support shaft 81; and a rotation member 82 that is provided with a hole part 82a into which the support shaft 81 is inserted and rotatable around the support shaft 81. The support shaft 81 is formed such that, with its outer peripheral surface as shaft side projections 81a, shaft side recesses 81b depressed in a direction approaching a rotation center with respect to the outer peripheral surface extend in an axial direction. The hole part 82a of the rotation member 82 is formed such that, with its inner peripheral surface as hole side projections 82a1, hole side recesses 82a2 depressed in a direction going away from the rotation center with respect to the inner peripheral surface extend in the axial direction. In a state in which the shaft side projections 81a are opposite to the hole side recesses 82a2 within a range in a circumferential direction of the hole side recesses 82a2, the rotation member 82 is relatively moved in the axial direction with respect to the support shaft 81.SELECTED DRAWING: Figure 7

Description

The present invention relates to a rotation mechanism provided with a rotating member that can rotate about a support shaft, and a transfer device and an image forming device provided with the rotation mechanism.

Conventionally, in an image forming apparatus such as a copying machine or a printer, a rotating mechanism provided with a rotating member that can rotate about a support shaft has been installed (see, for example, Patent Document 1). ..
Specifically, in Patent Document 1, the holding lever (rotating member) rotatably holds the primary transfer roller (roller member) that abuts on the intermediate transfer belt (image carrier). Further, the holding lever is held in the device housing so as to be rotatable around a support shaft installed in the device housing. Then, by rotating the holding lever around the support shaft, the primary transfer roller is brought into contact with and detached from the intermediate transfer belt.

On the other hand, Patent Document 2 describes a technique for forming a convex portion on the inner peripheral surface of a bearing member that pivotally supports the shaft portion of the photoconductor drum for the purpose of accurately and firmly determining the axial position of the photoconductor drum. Is disclosed.

In the conventional rotation mechanism, it is difficult to move the rotating member in the axial direction with respect to the support shaft when the outer diameter of the support shaft is not uniform in the axial direction.

The present invention has been made to solve the above-mentioned problems, and even when the outer diameter of the support shaft is not uniform in the axial direction, the rotating member is axially relative to the support shaft. It is an object of the present invention to provide a rotation mechanism, a transfer device, and an image forming device, which are easy to move to.

The rotation mechanism in the present invention includes a support shaft and a rotating member that is provided with a hole into which the support shaft is inserted and is rotatable around the support shaft, and the support shaft is the support shaft thereof. With the outer peripheral surface as the axial convex portion, the axial concave portion recessed in the direction closer to the rotation center with respect to the outer peripheral surface is formed so as to extend in the axial direction, and the hole portion of the rotating member is the inner circumference thereof. With the surface as the hole-side convex portion, the hole-side concave portion recessed in the direction away from the rotation center with respect to the inner peripheral surface is formed so as to extend in the axial direction, and the hole-side concave portion is formed within the circumferential direction of the hole-side concave portion. The rotating member is relatively moved in the axial direction with respect to the support shaft in a state where the shaft-side convex portion faces the hole-side concave portion.

According to the present invention, a rotation mechanism, a transfer device, and a transfer device, which can easily move a rotating member in the axial direction with respect to a support shaft even when the outer diameter of the support shaft is not uniform in the axial direction. , An image forming apparatus, can be provided.

It is an overall block diagram which shows the image forming apparatus in embodiment of this invention. It is sectional drawing which shows the image formation part. It is a block diagram which shows the intermediate transfer belt apparatus. It is a top view which shows a part of the intermediate transfer belt apparatus. It is a figure which shows the contacting and separating operation of an intermediate transfer belt apparatus. It is a perspective view which shows the rotation mechanism. It is a figure which shows the operation of a rotation mechanism. It is a figure which shows the state which the primary transfer roller is removed from the intermediate transfer belt apparatus. It is a schematic enlarged view which shows a part of the rotation mechanism. It is an enlarged sectional view which shows a part of the conventional rotation mechanism. It is an enlarged sectional view which shows a part of the rotation mechanism as a modification 1. FIG. FIG. 3 is an enlarged cross-sectional view showing a part of a rotation mechanism as a modification 2.

Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. In each figure, the same or corresponding parts are designated by the same reference numerals, and the duplicated description thereof will be appropriately simplified or omitted.

First, FIGS. 1 and 2 will explain the overall configuration and operation of the image forming apparatus 100.
FIG. 1 is a configuration diagram showing a printer as an image forming apparatus, and FIG. 2 is an enlarged view showing a part of an image forming portion thereof.
As shown in FIG. 1, an intermediate transfer belt device 15 as a transfer device is installed in the center of the image forming apparatus main body 100. Further, image forming portions 6Y, 6M, 6C, and 6K corresponding to each color (yellow, magenta, cyan, and black) are arranged side by side so as to face the intermediate transfer belt 8 (image carrier) of the intermediate transfer belt device 15. ing.

With reference to FIG. 2, the image forming unit 6Y corresponding to yellow includes a photoconductor drum 1Y, a charging device 4Y arranged around the photoconductor drum 1Y (photoreceptor), a developing device 5Y, and a cleaning device 2Y. It is composed of a lubricant supply device 3 and a static elimination device (not shown). Then, an image forming process (charging step, exposure step, developing step, transfer step, cleaning step, static elimination step) is performed on the photoconductor drum 1Y to form a yellow image on the surface of the photoconductor drum 1Y. become.

The other three image-forming units 6M, 6C, and 6K also have almost the same configuration as the image-forming unit 6Y corresponding to yellow, except that the toner colors used are different. The corresponding image is formed. Hereinafter, the description of the other three image forming units 6M, 6C, and 6K will be omitted as appropriate, and only the image forming unit 6Y corresponding to yellow will be described.

With reference to FIG. 2, the photoconductor drum 1Y is rotationally driven counterclockwise by the main motor. On the other hand, a charging bias is applied to the charging device 4Y by a power source. As a result, the surface of the photoconductor drum 1Y is uniformly charged at the position of the charging device 4Y (the charging step).
After that, the surface of the photoconductor drum 1Y reaches the irradiation position of the laser beam L emitted from the exposure apparatus 7, and the width direction at this position (the direction perpendicular to the paper surface of FIGS. 1 and 2 and the main scanning direction). An electrostatic latent image (exposure potential) corresponding to yellow is formed by the exposure scan (exposure step).

After that, the surface of the photoconductor drum 1Y reaches a position facing the developing device 5Y, and the electrostatic latent image is developed at this position to form a yellow toner image (a developing step).
After that, the surface of the photoconductor drum 1Y reaches the facing positions of the intermediate transfer belt 8 and the primary transfer roller 9Y, and the toner image formed on the surface of the photoconductor drum 1 at this position is on the surface of the intermediate transfer belt 8. Primary transfer is performed (it is a primary transfer step). At this time, a small amount of untransferred toner remains on the photoconductor drum 1Y.

After that, the surface of the photoconductor drum 1Y reaches a position facing the cleaning device 2Y, and the untransferred toner remaining on the photoconductor drum 1Y at this position is collected in the cleaning device 2Y by the cleaning blade 2a (cleaning). It is a process.).
Here, inside the cleaning device 2Y, a lubricant supply device 3 (lubricant supply device for a photoconductor) including a lubricant supply roller 3a, a solid lubricant 3b, a compression spring 3c, and the like is installed internally. Then, the lubricant supply roller 3a rotating clockwise in FIG. 2 scrapes the lubricant little by little from the solid lubricant 3b, and the lubricant supply roller 3a supplies the lubricant to the surface of the photoconductor drum 1Y. It will be.
Finally, the surface of the photoconductor drum 1Y reaches a position facing the static elimination device (not shown), and the residual potential on the photoconductor drum 1 is removed at this position.
In this way, a series of image forming processes performed on the photoconductor drum 1Y is completed.

The above-mentioned image forming process is performed in the other image forming sections 6M, 6C, and 6K in the same manner as in the yellow image forming section 6Y. That is, the laser beam L based on the image information is irradiated from the exposure apparatus 7 arranged above the image forming unit toward the photoconductor drums 1M, 1C, and 1K of the image forming units 6M, 6C, and 6K. Will be done. Specifically, the exposure apparatus 7 emits a laser beam L from a light source, scans the laser beam L with a rotation-driven polygon mirror, and irradiates the photoconductor drum via a plurality of optical elements. As the exposure apparatus 7, a plurality of LEDs arranged side by side in the width direction may be used.
After that, the toner images of each color formed on the photoconductor drums 1M, 1C, and 1K through the developing steps by the developing devices 5M, 5C, and 5K are superposed on the intermediate transfer belt 8 and primary transfer is performed. In this way, a color image is formed on the intermediate transfer belt 8.

Here, the intermediate transfer belt 8 as the image carrier is stretched and supported by a plurality of roller members 16 to 20, and is endlessly moved in the arrow direction in FIG. 3 by the rotational drive of the drive roller 16 by the drive motor. To.
The primary transfer rollers 9Y, 9M, 9C, and 9K (transfer rollers) as the four roller members each sandwich the intermediate transfer belt 8 between the photoconductor drums 1Y, 1M, 1C, and 1K, and are the primary transfer nip. Is forming. Then, a transfer voltage (primary transfer bias) having a polarity opposite to that of the toner is applied to the primary transfer rollers 9Y, 9M, 9C, and 9K.
Then, the intermediate transfer belt 8 travels in the direction of the arrow and sequentially passes through the primary transfer nips of the primary transfer rollers 9Y, 9M, 9C, and 9K. In this way, the toner images of the respective colors on the photoconductor drums 1Y, 1M, 1C, and 1K are superimposed on the surface of the intermediate transfer belt 8 and primaryly transferred (the primary transfer step).

After that, the intermediate transfer belt 8 (image carrier) on which the toner images of each color are superimposed and primary transferred reaches the position facing the secondary transfer roller 40. At this position, the secondary transfer facing roller 19 sandwiches the intermediate transfer belt 8 with the secondary transfer roller 74 to form a secondary transfer nip. Then, the four-color toner images formed on the intermediate transfer belt 8 are secondarily transferred onto the sheet P of the paper or the like conveyed to the position of the secondary transfer nip (this is the secondary transfer step). .. At this time, untransferred toner that has not been transferred to the sheet P remains on the intermediate transfer belt 8.

After that, the intermediate transfer belt 8 reaches the position of the intermediate transfer cleaning device 10. Then, at this position, deposits such as untransferred toner adhering to the surface of the intermediate transfer belt 8 are removed.
In this way, a series of transfer processes performed on the intermediate transfer belt 8 is completed.

Here, referring to FIG. 1, the sheet P conveyed to the position of the secondary transfer nip is from the paper feed device 26 arranged below the device main body 100 to the paper feed roller 27, the resist roller pair 28, and the like. It is transported via.
Specifically, in the paper feed device 26, a plurality of sheets P such as paper are stacked and stored. Then, when the paper feed roller 27 is rotationally driven in the counterclockwise direction in FIG. 1, the top sheet P is fed to the rollers of the resist roller vs. 28 via the transport path.

The sheet P conveyed to the resist roller pair 28 (timing roller pair) temporarily stops at the position of the roller nip of the resist roller pair 28 that has stopped the rotational drive. Then, the resist roller pair 28 is rotationally driven in time with the color image on the intermediate transfer belt 8, and the sheet P is conveyed toward the secondary transfer nip. In this way, the desired color image is transferred onto the sheet P.

After that, the sheet P on which the color image is transferred at the position of the secondary transfer nip is transferred to the position of the fixing portion 50 by the transfer belt 60. Then, at this position, the color image transferred to the surface is fixed on the sheet P by the heat and pressure of the fixing belt and the pressure roller (the fixing step).
After that, the sheet P is discharged to the outside of the device by the paper discharge roller pair via the transport path. The sheets P discharged to the outside of the device by the paper ejection roller pair are sequentially stacked on the stack portion as an output image.
In this way, a series of image forming operations (printing) in the image forming apparatus is completed.

Next, with reference to FIG. 2, the configuration and operation of the developing device 5Y (developing device) in the image forming unit will be described in more detail.
The developing apparatus 5Y includes a developing roller 51Y facing the photoconductor drum 1Y, a doctor blade 52Y facing the developing roller 51Y, two transport screws 55Y disposed in the developing agent accommodating portion, and a toner concentration in the developing agent. It is composed of a concentration detection sensor 56Y that detects the above, and the like. The developing roller 51Y is composed of a magnet fixed inside, a sleeve rotating around the magnet, and the like. A two-component developer G composed of a carrier and toner is housed in the developer accommodating portion.

The developing device 5Y configured in this way operates as follows.
The sleeve of the developing roller 51Y is rotated in the direction of the arrow in FIG. Then, the developer G supported on the developing roller 51Y by the magnetic field formed by the magnet moves on the developing roller 51Y as the sleeve rotates. Here, the developer G in the developing device 5Y is adjusted so that the ratio of the toner (toner concentration) in the developing agent G is within a predetermined range. Specifically, when a low toner concentration is detected by the toner concentration sensor installed in the developing device 5Y, new toner is discharged from the toner container 58 into the developing device 5Y so that the toner concentration is within a predetermined range. Be replenished.
After that, the toner replenished from the toner container 58 into the developer accommodating portion circulates in the two isolated developer accommodating portions while being mixed and stirred together with the developer G by the two transport screws 55Y (FIG. 2). It is a movement in the vertical direction of the paper.) Then, the toner in the developer G is adsorbed on the carrier by triboelectric charging with the carrier, and is supported on the developing roller 51Y together with the carrier by the magnetic force formed on the developing roller 51Y.

The developer G supported on the developing roller 51Y is conveyed in the direction of the arrow in FIG. 2 and reaches the position of the doctor blade 52Y. Then, the developer G on the developing roller 51Y is conveyed to a position facing the photoconductor drum 1Y (a developing region) after the amount of the developer is adjusted to an appropriate amount at this position. Then, the toner is adsorbed on the latent image formed on the photoconductor drum 1Y by the electric field formed in the developing region. After that, the developer G remaining on the developing roller 51Y reaches the upper part of the developing agent accommodating portion as the sleeve rotates, and is separated from the developing roller 51Y at this position. The electric field formed in the developing region is formed by the potential difference between the developing bias applied to the developing roller 51Y by the developing power supply 91 and the exposure potential on the photoconductor drum 1Y.
The toner container 58 is detachably installed (replaceable) with respect to the developing device 5Y (image forming device 100). When the new toner contained therein is emptied, the toner container 58 is removed from the developing device 5Y (image forming device 100) and replaced with a new one.

Hereinafter, the intermediate transfer belt device 15 (transfer device) in the present embodiment will be described with reference to FIG. 3 and the like.
As shown in FIG. 3, the intermediate transfer belt device 15 as a transfer device includes an intermediate transfer belt 8 as an image carrier, primary transfer rollers 9Y, 9M, 9C, 9K, and drive rollers 16 as four transfer rollers. It is composed of a driven roller 17, a pre-transfer roller 18, a secondary transfer facing roller 19, a tension roller 20, an intermediate transfer cleaning device 10, a rotation mechanism 80 (see FIG. 4), and the like.

The intermediate transfer belt 8 (image carrier) abuts on four photoconductor drums 1Y, 1M, 1C, and 1K carrying toner images of each color to form a primary transfer nip. The intermediate transfer belt 8 is stretched and supported by a plurality of roller members (driving roller 16, driven roller 17, pre-transfer roller 18, secondary transfer opposed roller 19, tension roller 20, and the like).

In the present embodiment, the intermediate transfer belt 8 has PVDF (vinylidene fluoride), ETFE (ethylene-ethylene tetrafluoride copolymer), PI (polyimide), PC (polycarbonate), etc. in a single layer or a plurality of layers. It is configured to disperse a conductive material such as carbon black. The intermediate transfer belt 8 is adjusted so that the volume resistivity is in the range of ¹⁰⁷ to 10 ¹² Ωcm and the surface resistivity of the back surface side of the belt is in the range of 10 ⁸ to 10 ¹² Ωcm. Further, the intermediate transfer belt 8 is set so that the thickness is in the range of 80 to 100 μm. In this embodiment, the thickness of the intermediate transfer belt 8 is set to 90 μm.
If necessary, the surface of the intermediate transfer belt 8 can be coated with a release layer. At that time, as the material used for the coating, ETFE (ethylene-tetrafluoroethylene copolymer), PTFE (polytetrafluorinated ethylene), PVDF (vinyl fluoride den), PEA (perfluoroalkoxyfluororesin), FEP (four). Fluororesin such as ethylene fluoride-propylene hexafluoride copolymer), PVF (vinyl fluoride) and the like can be used, but the present invention is not limited thereto.
Further, as a method for manufacturing the intermediate transfer belt 8, there are a casting method, a centrifugal molding method, and the like, and a step of polishing the surface thereof is performed as necessary.

The primary transfer rollers 9Y, 9M, 9C, and 9K as transfer rollers are roller members that abut on the corresponding photoconductor drums 1Y, 1M, 1C, and 1K via the intermediate transfer belt 8, respectively. Specifically, the transfer roller 9Y for yellow abuts on the photoconductor drum 1Y for yellow via the intermediate transfer belt 8, and the transfer roller 9M for magenta abuts on the photoconductor drum 1M for magenta via the intermediate transfer belt 8. The transfer roller 9C for cyan is in contact with the photoconductor drum 1C for cyan via the intermediate transfer belt 8, and the transfer roller 9K for black (for black) is black via the intermediate transfer belt 8. It is in contact with the photoconductor drum 1K for use (for black). The primary transfer rollers 9Y, 9M, 9C, and 9K are elastic rollers in which a conductive sponge layer is formed on a core metal, respectively, and have a volume resistance of 10 ⁶ to 10 ¹² Ω (preferably 10 ⁷ to 10). It is adjusted to be in the range of ⁹ Ω).

The drive roller 16 is located on the downstream side of the traveling direction of the intermediate transfer belt with respect to the four photoconductor drums, and the inner circumference of the intermediate transfer belt 8 is wound with the intermediate transfer belt 8 wound at a winding angle of about 120 degrees. It is arranged so as to abut on the surface. The drive roller 16 is rotationally driven clockwise in FIG. 3 by a drive motor controlled by a control unit. As a result, the intermediate transfer belt 8 moves in a predetermined movement direction (clockwise in FIG. 3).

The driven roller 17 is inside the intermediate transfer belt 8 in a state where the intermediate transfer belt 8 is wound at a winding angle of about 180 degrees at a position upstream of the traveling direction of the intermediate transfer belt 8 with respect to the four photoconductor drums. It is arranged so as to abut on the peripheral surface. The driven roller 17 rotates in the clockwise direction of FIG. 3 as the intermediate transfer belt 8 moves (runs).

The tension roller 20 is in contact with the outer peripheral surface of the intermediate transfer belt 8. The pre-transfer roller 18 and the secondary transfer opposed roller 19 are in contact with the inner peripheral surface of the intermediate transfer belt 8.
All of the roller members 17 to 20 except the drive roller 16 rotate in a driven manner as the intermediate transfer belt 8 moves (runs).
An intermediate transfer cleaning device 10 is installed at a position between the secondary transfer facing roller 19 and the tension roller 20. A cleaning blade is installed in the intermediate transfer cleaning device 10.

With reference to FIG. 3, the secondary transfer facing roller 19 is in contact with the secondary transfer roller 40 via the intermediate transfer belt 8. The secondary transfer facing roller 19 is an NBR having a volume resistance of about ¹⁰⁷ to ¹⁰⁸ Ω and a hardness (JIS-A hardness) of about 48 to 58 degrees on the outer peripheral surface of a cylindrical core metal made of stainless steel or the like. An elastic layer made of rubber (the layer thickness is about 5 mm) is formed.

Further, in the present embodiment, the secondary transfer facing roller 19 is electrically connected to the power supply unit, and a secondary transfer bias having a high voltage of about −5 kV is applied from the power supply unit. The secondary transfer bias applied to the secondary transfer facing roller 19 is for secondary transfer of the toner image primary transfer to the surface of the intermediate transfer belt 8 to the sheet P conveyed to the secondary transfer nip. This is a repulsive transfer of a secondary transfer bias (DC voltage) having the same polarity as the polarity of the toner (which is a negative polarity in the present embodiment). As a result, the toner supported on the toner supporting surface (outer peripheral surface) of the intermediate transfer belt 8 is electrostatically moved from the secondary transfer facing roller 40 side to the secondary transfer belt device 69 side by the secondary transfer electric field. become.
The secondary transfer bias may be a tatami mat of an AC voltage as a DC voltage, or may be an attractive transfer applied to the secondary transfer roller 40.

Hereinafter, in the present embodiment, the rotation mechanism 80 installed in the intermediate transfer belt device 15 (transfer device) will be described in detail.
With reference to FIGS. 4, 5 and the like, the rotation mechanism 80 in the present embodiment includes primary transfer rollers 9Y, 9M, 9C, 9K as roller members (transfer rollers), and an intermediate transfer belt 8 (toner image). It is a mechanism for making it possible to attach and detach to an image carrier that carries.).
The rotation mechanism 80 is installed at both ends of each of the four primary transfer rollers 9Y, 9M, 9C, and 9K in the axial direction (vertical direction in FIG. 4 and vertical direction on the paper surface in FIG. 5). Has been done.
The rotation mechanism 80 in which the four primary transfer rollers 9Y, 9M, 9C, and 9K are installed is configured and operates in almost the same manner, and the rotation mechanism 80 installed on both sides in the axial direction is Since they are configured and operate in almost the same manner except for the point of being a target shape, only the one-sided rotation mechanism 80 corresponding to the black primary transfer roller 9K will be described below as appropriate.

As shown in FIGS. 4 to 6 and the like, the rotation mechanism 80 is mainly composed of a support shaft 81 and a rotation member 82.
The support shaft 81 is fixedly installed on the device housing 90 of the intermediate transfer belt device 15 (a housing that rotatably holds a plurality of roller members 16 to 20). In the present embodiment, the support shaft 81 and the device housing 90 are made of a resin material in order to reduce the weight and cost. In particular, in the present embodiment, the support shaft 81 is integrally formed by injection molding as one component together with the device housing 90.
The rotating member 82 is formed with a hole 82a (see FIGS. 6, 9 and the like) into which the support shaft 81 is inserted, and is configured to be rotatable around the support shaft 81. Specifically, the rotating member 82 is configured to be rotatable around the support shaft 81. Further, the rotating member 82 rotatably holds the primary transfer roller 9K (roller member). Specifically, the shaft portion of the primary transfer roller 9K is inserted into the second hole portion 82a (see FIG. 9) of the rotating member 82.

The rotation mechanism 80 configured in this way causes the primary transfer rollers 9Y, 9M, 9C, and 9K to be brought into contact with and separated from the intermediate transfer belt 8.
Specifically, the image forming apparatus 100 in the present embodiment has a "full color mode" in which printing is performed using all four colors (yellow, magenta, cyan, and black), and three colors excluding black among the four colors. It is configured to be able to switch between a "color mode" in which printing is performed using and a "monochrome mode" in which printing is performed using only black among the four colors.
Then, when the "full color mode" is selected by the user, as shown in FIG. 5A, all four primary transfer rollers 9Y, 9M, 9C, and 9K abut on the intermediate transfer belt 8 and 1 Each rotation mechanism 80 is rotation-controlled so as to form a next transfer nip.
On the other hand, when the "color mode" is selected by the user, as shown in FIG. 5 (B), only the primary transfer roller 9K for black is separated from the intermediate transfer belt 8 and the primary transfer is performed. Each rotation mechanism 80 is rotation-controlled so that a nip is not formed.
Further, when the "monochrome mode" is selected by the user, as shown in FIG. 5C, only the primary transfer roller 9K for black abuts on the intermediate transfer belt 8 and the other three 1's are in contact with each other. The rotation of each of the rotation mechanisms 80 is controlled so that the secondary transfer rollers 9Y, 9M, and 9C are separated from the intermediate transfer belt 8 so that the primary transfer nip is not formed.
By performing such contact / detachment operation, the primary transfer nip of the unused color is not formed in each mode, so that the mechanical wear of the photoconductor drum and the primary transfer roller of the unused color is reduced. can do.

Here, as shown in FIGS. 6 and 7, in the rotation mechanism 80 of the present embodiment, neither the support shaft 81 nor the hole portion 82a of the rotation member 82 has a circular cross section. Therefore, a recess is formed in the cross section.
That is, both the support shaft 81 and the hole portion 82a are formed in an uneven shape.

With reference to FIGS. 6 and 7, the support shaft 81 is centered on rotation with respect to the outer peripheral surface (shaft-side convex portion 81a) with its outer peripheral surface as the axial-side convex portion 81a (shown by a alternate long and short-dashed line in FIG. 6). The shaft-side recess 81b, which is recessed in the direction approaching the center of the shaft, is formed so as to extend in the axial direction.
Specifically, the support shaft 81 is formed with a plurality of shaft-side convex portions 81a and shaft-side concave portions 81b alternately formed in the circumferential direction. More specifically, in the present embodiment, three axial-side convex portions 81a having substantially the same circumferential length (arc length) are arranged substantially evenly in the circumferential direction with the axial-side concave portion 81b interposed therebetween. There is. Further, the three shaft-side recesses 81b are formed to have substantially the same length in the circumferential direction and substantially the same depth in the radial direction thereof.

With reference to FIGS. 6 and 7, the hole portion 82a of the rotating member 82 has an inner peripheral surface as a hole-side convex portion 82a1 and a rotation center with respect to the inner peripheral surface (hole-side convex portion 82a1) (FIG. 6). The hole-side recess 82a2, which is recessed in the direction away from the axial center shown by the alternate long and short dash line in No. 6, is formed so as to extend in the axial direction.
Specifically, in the hole portion 82a, a plurality of hole-side convex portions 82a1 and a plurality of hole-side concave portions 82a2 are alternately formed in the circumferential direction according to the number and position of the plurality of shaft-side convex portions 81a and the shaft-side concave portions 81b. There is. More specifically, in the present embodiment, three hole-side convex portions 82a1 having substantially the same circumferential length (arc length) are arranged substantially evenly in the circumferential direction with the hole-side concave portion 82a2 interposed therebetween. There is. Further, the three hole-side recesses 82a2 are formed to have substantially the same length in the circumferential direction and substantially the same depth in the radial direction thereof.

In the rotating mechanism 80 in which the support shaft 81 and the hole 82a are configured in this way, the shaft-side convex portion 81a faces the hole-side recess 82a2 within the circumferential direction of the hole-side concave portion 82a2 (FIG. 7). In the state (C)), the rotating member 82 is moved relative to the support shaft 81 in the axial direction (the direction indicated by the arrow in FIGS. 6 and 8 or the opposite direction). It is configured to move.
That is, in the present embodiment, when the rotating member 82 is relatively moved in the axial direction with respect to the support shaft 81, the shaft side convex portion 81a (outer peripheral surface) becomes the hole side convex portion 82a1 (inner peripheral surface). It is not performed in a state of facing (contacting) the shaft side convex portion 81a (outer peripheral surface), but in a state of facing the hole side concave portion 82a2.

The manual operation of moving the rotating member 82 in the axial direction (thrust direction) with respect to the support shaft 81 in this way is assembling the intermediate transfer belt device 15 by a worker in a manufacturing factory or by a serviceman in the market. This is performed when the primary transfer roller 9K is attached to and detached from the intermediate transfer belt device 15 for parts replacement or maintenance of the transfer roller 9K.
For details, refer to FIG. 8, when removing the primary transfer roller 9K from the intermediate transfer belt device 15, first, the intermediate transfer belt 8 and the like are removed to expose the primary transfer roller 9K and the rotation mechanism 80. Put it in the state of Then, the rotating member 82 of the rotating mechanism 80 is slidably moved in the arrow direction on the support shaft 81 (movement from the position indicated by the broken line to the position indicated by the solid line) to be primary with respect to the rotating member 82. The fitting of the transfer roller 9K is released. Then, the primary transfer roller 9K is removed from the intermediate transfer belt device 15.
When the primary transfer roller 9K is attached to the intermediate transfer belt device 15, the operation is performed in the reverse procedure to the above-mentioned removal procedure.

As described above, the rotating mechanism 80 in the present embodiment moves the rotating member 82 relative to the support shaft 81 in the axial direction (shifts the position in the axial direction), thereby moving the rotating member 82 to the rotating member 82. On the other hand, a primary transfer roller 9K (a roller member rotatably held by the rotating member 82) is attached and detached.
Then, such an attachment / detachment operation is performed in a state where the shaft-side convex portion 81a faces the hole-side convex portion 82a1 (the states of FIGS. 6, 7 (A), (B), and 9 (A)). It is not performed, but is performed in a state where the convex portion 81a on the shaft side faces the concave portion 82a2 on the hole side (the state shown in FIGS. 7 (C) and 9 (B)).
That is, in a state where the shaft-side convex portion 81a faces the hole-side concave portion 82a2 (the states of FIGS. 7C and 9B), the rotating member 82 is placed at the base of the support shaft 81 (main body casing). It is a portion held by the body 90) and slid to release the fitting of the primary transfer roller 9K to the rotating member 82, or the rotating member 82 is moved to the tip portion (root portion) of the support shaft 81. The primary transfer roller 9K is fitted to the rotating member 82 by sliding and moving in the direction of).

As a result, even when the outer diameter of the support shaft 81 is not uniform over the axial direction, it becomes easy to move the rotating member 82 relative to the support shaft 81 in the axial direction.
In particular, as shown in FIG. 9, the support shaft 81 in the present embodiment has an outer diameter that becomes smaller (gradually decreases) from the root portion (the portion held by the main body housing 90) to the tip portion. It is formed. As described above, the support shaft 81 is formed of a resin material by injection molding together with the device housing 90, and is formed to facilitate the draft on the molding (the molded product can be easily taken out from the mold). This is due to the influence of). As described above, since the outer diameter of the support shaft 81 in the present embodiment is not uniform in the axial direction, the support shaft 81 and the hole portion 82a are formed in an uneven shape as in the present embodiment. Will be useful.

Specifically, as in the rotation mechanism 180 shown in FIG. 10, when both the support shaft 181 and the hole portion 182a of the rotation member 182 have a circular cross section, the outer diameter gradually increases from the tip portion to the root portion. When the rotating member 182 is moved toward the root portion with respect to the support shaft 181 formed in the above, the hole portion 182a is in a state of being bitten by the support shaft 181 as shown by the broken line. Therefore, the axial movement of the rotating member 182 is restricted, and there is a possibility that the primary transfer roller 9K cannot be removed from the rotating member.
In order to solve such a problem at the time of attachment / detachment, the rotating member 182 is positioned at the position at the time of use (the position shown by the solid line in FIG. 10) in consideration of the draft of the support shaft 181. It is also conceivable to set a large difference between the outer diameter of the support shaft 181 and the inner diameter of the hole 182a in the present state. However, in that case, the rotating member 182 is held in a state of rattling with respect to the support shaft 181 during use. In such a case, the primary transfer nip is not stable, and a good primary transfer step is not performed, resulting in transfer failure.
That is, the rotation mechanism 180 shown in FIG. 10 has the mobility to move the rotation member 182 in the axial direction with respect to the support shaft 181 at the time of attachment / detachment, and the rotation member 182 does not rattle on the support shaft 181 at the time of use. It is difficult to achieve both the holding property and the holding property, and its use is limited.

On the other hand, the rotation mechanism 80 in the present embodiment moves the rotating member 82 toward the root portion with respect to the support shaft 81 formed so that the outer diameter gradually increases from the tip portion to the root portion. The posture of the rotating member 82 in the rotation direction (FIG. 9) so that the hole-side concave portion 82a2 faces the shaft-side convex portion 81a (the state shown in FIG. 9B). 7 (C) is the posture shown in (C).) Therefore, unlike the rotating member 82 shown by the broken line in FIG. 9B, the hole portion 82a is less likely to be in a state of being bitten by the support shaft 81. Therefore, the movement of the rotating member 82 in the axial direction is not restricted, and the primary transfer roller 9K can be easily removed from the rotating member.
As described above, in the present embodiment, a sufficient gap (a gap surrounded by a broken line in FIG. 9B) is formed between the support shaft 81 and the hole portion 82a at the time of attachment / detachment. That is, when the shaft-side convex portion 81a faces the hole-side concave portion 82a2, the support shaft 81 and the hole portion 82a are not in contact with each other.

Further, in the rotation mechanism 80 in the present embodiment, the shaft side convex portion 81a is convex on the hole side when it is used (when it is not during attachment / detachment and when normal printing operation or the like is performed). The posture in the rotation direction of the rotating member 82 (the posture shown in FIGS. 6, 7A and 7B) is determined so as to face the portion 82a1. Therefore, as shown in FIG. 9A, it is difficult for a gap to be formed between the support shaft 81 and the hole portion 82a, and the rotating member 82 is held without rattling with respect to the support shaft 81. Therefore, the primary transfer nip is stable and a good primary transfer step is performed.
That is, the rotation mechanism 80 in the present embodiment has the mobility to move the rotation member 82 in the axial direction with respect to the support shaft 81 at the time of attachment / detachment, and the rotation member 82 rattles at the support shaft 81 at the time of use. It is possible to achieve both retention and retention.

Here, in the rotation mechanism 80 of the present embodiment, the shaft-side convex portion 81a is in contact with the hole-side convex portion 82a1 (FIGS. 6, 7 (A), (B), and 9 (A)). In this state, the rotating member 82 is required to perform the contact / detachment operation of the primary transfer roller described above with reference to FIG. 5 in a predetermined rotation range around the support shaft 81. It is configured to be rotatable within the rotation range.).
Specifically, the rotating mechanism 80 may move the rotating member 82 in the axial direction with respect to the support shaft 81 in a state where the shaft-side convex portion 81a is in contact with the hole-side convex portion 82a1. The rotating member 82 is configured to be rotatable around the support shaft 81 within a predetermined rotation range.
As shown in FIGS. 5A and 5C, when the primary transfer roller 9K is brought into contact with the intermediate transfer belt 8, the posture of the rotating member 82 in the rotational direction is as shown in FIG. 7A. Become. On the other hand, as shown in FIG. 5 (B), when the primary transfer roller 9K is separated from the intermediate transfer belt 8, the posture of the rotating member 82 in the rotation direction is as shown in FIG. 7 (B). Become. Then, when the rotating member 82 rotates between the rotation position shown in FIG. 7 (A) and the rotation position shown in FIG. 7 (B) (rotation range), the hole-side convex portion 82a1 and the shaft side It is always in contact with the convex portion 81a. Then, in such a state, even if the rotating member 82 is to be slid to the side of the root portion of the support shaft 81, as shown in FIG. 9A, the rotating member 82 is slid to move due to the draft of the support shaft 81. Will not be possible. In this embodiment, in order to determine the axial position of the rotating member 82 with respect to the support shaft 81 during use, the tip side of the rotating member 82 (on the right side of FIG. 9A). It is preferable to detachably install a restricting member such as a retaining ring that restricts the movement of the support shaft 81 on the support shaft 81.

Then, the rotation mechanism 80 in the present embodiment rotates from the state where the shaft side convex portion 81a is in contact with the hole side convex portion 82a1 (the state of FIGS. 7A and 7B). The member 82 is rotated around the support shaft 81 outside the above-mentioned rotation range, and the shaft-side convex portion 81a faces the hole-side concave portion 82a2 (in the state of FIG. 7C). Become.
That is, when the rotating member 82 rotates between the rotation position shown in FIG. 7 (A) and the rotation position shown in FIG. 7 (B) (rotation range), the hole-side convex portion 82a1 and the shaft side The convex portion 81a is always in contact with the convex portion 81a, but when the rotating member 82 is rotated beyond the rotation range, the hole-side convex portion 82a1 and the shaft-side convex portion 81a face each other. (The contact between the hole-side convex portion 82a1 and the shaft-side convex portion 81a is released). This makes it possible to slide the rotating member 82 to the root side (the left side of FIG. 9B) of the support shaft 81.

Here, the rotation mechanism 80 in the present embodiment is configured such that the outer diameter R1 of the shaft-side convex portion 81a is smaller than the inner diameter R2 of the hole-side concave portion 82a2. Regarding R1 and R2, FIG. 7A can be referred to, and the relationship R1 <R2 is established.
With this configuration, the support shaft 81 and the hole 82a are less likely to come into contact with each other during attachment / detachment (when the shaft side convex portion 81a faces the hole side concave portion 82a2), and the support shaft 81 The sliding movement of the rotating member 82 with respect to the relative is facilitated.

In addition, referring to FIG. 7A, in the present specification and the like, the “outer diameter of the convex portion on the shaft side” is the rotation center of the support shaft 81 (the shaft center shown by the alternate long and short dash line in FIG. 6). ) Is defined as the distance R1 (radius) in the direction orthogonal to the center of rotation from the convex portion 81a on the axial side to the outer peripheral surface.
Similarly, with reference to FIG. 7A, in the present specification and the like, the “inner diameter of the hole-side recess” is the hole-side recess 82a2 from the center of the hole (the center of rotation of the support shaft 81). It is defined as the distance R2 (radius) in the direction orthogonal to the center of rotation to the inner peripheral surface of.

Further, in the rotation mechanism 80 of the present embodiment, the circumferential length H1 (arc length) of the shaft-side convex portion 81a is shorter than the circumferential length H2 (arc length) of the hole-side concave portion 82a2. It is configured as follows. Regarding the lengths H1 and H2 in the circumferential direction, FIG. 7A can be referred to, and the relationship H1 <H2 is established.
With this configuration, the support shaft 81 and the hole 82a are less likely to come into contact with each other during attachment / detachment (when the shaft side convex portion 81a faces the hole side concave portion 82a2), and the support shaft 81 The sliding movement of the rotating member 82 with respect to the relative is facilitated.

Further, the rotation mechanism 80 in the present embodiment is configured such that the outer diameter R1 of the shaft-side convex portion 81a is substantially the same as the inner diameter R3 of the hole-side convex portion 82a1 (R1≈R3). ..
With this configuration, when in use (when the shaft-side convex portion 81a faces the hole-side convex portion 82a1), the support shaft 81 and the hole portion 82a do not play and the rotating member 82 does not play. Allows for smooth rotation.

<Modification 1>
As shown in FIG. 11, also in the rotation mechanism 80 in the first modification, the support shaft 81 is formed so that the outer diameter of the tip portion is smaller than the outer diameter of the root portion. Specifically, the support shaft 1 in the modified example 1 is formed in a tapered shape so that the outer diameter gradually decreases from the root portion to the tip portion due to the draft, as in the case of FIG.
Then, in the hole portion 82a of the rotating member 82 in the first modification, the inner diameter on the side corresponding to the root portion is larger than the inner diameter on the side corresponding to the tip portion according to the shape of the outer peripheral surface of the support shaft 81. It is formed. Specifically, unlike the one in FIG. 9, the hole portion 82a in the first modification is formed in a tapered shape so that the inner diameter gradually decreases from the root portion to the tip portion according to the shape of the support shaft 81.
Further, also in the first modification, the support shaft 81 is provided with the shaft-side convex portion 81a and the shaft-side concave portion 81b, and the hole-side convex portion 82a1 and the hole-side concave portion 82a2 are provided in the hole portion 82a. Similarly, as shown in FIG. 11A, the rotating member 82 is rotated during use, and as shown in FIG. 11B, the rotating member 82 is slid and moved during attachment / detachment. There is.
Even in this configuration, the rotating member 82 can be easily moved in the axial direction with respect to the support shaft 81.

<Modification 2>
As shown in FIG. 12, also in the rotation mechanism 80 in the second modification, the support shaft 81 is formed so that the outer diameter of the tip portion is smaller than the outer diameter of the root portion. However, unlike the support shafts 1 in FIGS. 9 and 11, the outer diameter from the root portion to the predetermined position is uniformly large, and the outer diameter from the predetermined position to the tip portion is uniformly small. It is formed in a stepped manner.
Then, in the hole portion 82a of the rotating member 82 in the second modification, the inner diameter on the side corresponding to the root portion is larger than the inner diameter on the side corresponding to the tip portion according to the shape of the outer peripheral surface of the support shaft 81. It is formed in steps.
Further, also in the second modification, the support shaft 81 is provided with the shaft-side convex portion 81a and the shaft-side concave portion 81b, and the hole-side convex portion 82a1 and the hole-side concave portion 82a2 are provided in the hole portion 82a. Similarly, as shown in FIG. 12 (A), the rotating member 82 is rotated during use, and as shown in FIG. 12 (B), the rotating member 82 is slid and moved during attachment / detachment. There is.
Even in this configuration, the rotating member 82 can be easily moved in the axial direction with respect to the support shaft 81.

As described above, the rotation mechanism 80 in the present embodiment includes the support shaft 81 and the hole portion 82a into which the support shaft 81 is inserted, and is a rotating member 82 that can rotate around the support shaft 81. And are provided. The support shaft 81 is formed so that the outer peripheral surface thereof is used as the axial convex portion 81a, and the axial concave portion 81b recessed in the direction closer to the rotation center with respect to the outer peripheral surface extends in the axial direction. Further, the hole portion 82a of the rotating member 82 has an inner peripheral surface as a hole-side convex portion 82a1 so that the hole-side concave portion 82a2 recessed in a direction away from the rotation center with respect to the inner peripheral surface extends in the axial direction. It is formed. Then, the rotating member 82 is relatively moved in the axial direction with respect to the support shaft 81 in a state where the shaft-side convex portion 81a faces the hole-side recess 82a2 within the circumferential range of the hole-side recess 82a2. ..
Thereby, even if the outer diameter of the support shaft 81 is not uniform in the axial direction, the rotating member 82 can be easily moved in the axial direction with respect to the support shaft 81.

In the present embodiment, the rotation mechanism 80 installed in the intermediate transfer belt device 15 as the transfer device provided with the primary transfer roller 9K that is brought into contact with and separated from the intermediate transfer belt 8 as the image carrier. The present invention has been applied. However, the application of the present invention is not limited to this, and the present invention is also applied to, for example, a rotation mechanism installed in a transfer device provided with a transfer roller that is brought into contact with and detached from a photoconductor drum as an image carrier. The present invention can be applied. Further, the present invention also relates to a rotation mechanism for bringing an object other than the transfer roller (for example, a cleaning blade 2a, etc.) into contact with a contacted body (for example, a photoconductor drum 1Y). The invention can be applied. Further, the application of the present invention is not limited to the rotation mechanism installed in the image forming apparatus, and all of them are used as long as there is an application for moving the rotating member in the axial direction with respect to the support shaft. The present invention can be applied to the above.
Further, in the present embodiment, the support shaft 81 is made of a resin material, but the material of the support shaft 81 is not limited to this, and for example, the support shaft 81 can be made of a metal material.
And even in such a case, the same effect as that of this embodiment can be obtained.

Further, it is clear that the present invention is not limited to the present embodiment, and within the scope of the technical idea of the present invention, the present embodiment may be appropriately modified in addition to the suggestions in the present embodiment. be. Further, 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 carrying out the present invention can be used.

1Y, 1M, 1C, 1K Photoreceptor Drum,
8 Intermediate transfer belt (image carrier),
15 Intermediate transfer belt device (transfer device),
9Y, 9M, 9C, 9K primary transfer roller (roller member, transfer roller),
80 rotation mechanism,
81 Support shaft,
81a Shaft side convex part (outer peripheral surface),
81b Shaft side recess,
82 Rotating member,
82a hole,
82a1 Hole side convex part (inner peripheral surface),
82a2 hole side recess,
100 Image forming apparatus (image forming apparatus main body).

Japanese Unexamined Patent Publication No. 2014-178510 Japanese Unexamined Patent Publication No. 2012-113214

Claims (12)

Support axis and
A rotating member that is provided with a hole into which the support shaft is inserted and that can rotate around the support shaft.
Equipped with
The support shaft is formed so that the outer peripheral surface thereof is a convex portion on the axial side and the concave portion on the axial side recessed in the direction closer to the center of rotation with respect to the outer peripheral surface extends in the axial direction.
The hole portion of the rotating member is formed so that the inner peripheral surface thereof is a hole-side convex portion and the hole-side concave portion recessed in the direction away from the rotation center with respect to the inner peripheral surface extends in the axial direction. ,
It is characterized in that the rotating member is relatively moved in the axial direction with respect to the support shaft in a state where the shaft-side convex portion faces the hole-side recess within the range in the circumferential direction of the hole-side concave portion. Rotating mechanism. Claim 1 is characterized in that the rotating member can rotate around the support shaft within a predetermined rotation range in a state where the shaft-side convex portion is in contact with the hole-side convex portion. The rotation mechanism described in 1. From the state where the shaft-side convex portion is in contact with the hole-side convex portion, the rotating member is rotated around the support shaft to the outside of the rotation range, and the shaft-side convex portion is said. The rotation mechanism according to claim 2, wherein the rotation mechanism faces the recess on the hole side. The invention according to any one of claims 1 to 3, wherein when the shaft-side convex portion faces the hole-side concave portion, the support shaft and the hole portion are not in contact with each other. Rotation mechanism. In the support shaft, a plurality of shaft-side convex portions and the shaft-side concave portions are alternately formed in the circumferential direction.
The hole portion is characterized in that a plurality of the hole-side convex portion and the hole-side concave portion are alternately formed in the circumferential direction according to the number and position of the plurality of the shaft-side convex portion and the shaft-side concave portion. The rotation mechanism according to any one of claims 1 to 4. The rotation mechanism according to any one of claims 1 to 5, wherein the outer diameter of the shaft-side convex portion is smaller than the inner diameter of the hole-side concave portion. The rotation mechanism according to any one of claims 1 to 6, wherein the axial length of the shaft-side convex portion is shorter than the circumferential length of the hole-side concave portion. The rotation mechanism according to any one of claims 1 to 7, wherein the support shaft is formed so that the outer diameter becomes smaller from the root portion to the tip portion. The support shaft is formed so that the outer diameter of the tip portion is smaller than the outer diameter of the root portion.
The hole portion is according to any one of claims 1 to 8, wherein the hole portion is formed so that the inner diameter of the side corresponding to the root portion is larger than the inner diameter of the side corresponding to the tip portion. The rotating mechanism described. The rotating member holds the roller member rotatably and holds it rotatably.
One of claims 1 to 9, wherein the roller member is attached to and detached from the rotating member by moving the rotating member relative to the supporting shaft in the axial direction. The rotation mechanism described in 1. A transfer device provided with a transfer roller that can be brought into contact with and detached from an image carrier that supports a toner image.
The rotation mechanism according to any one of claims 1 to 10 is provided.
The rotating member is a transfer device characterized by holding the transfer roller rotatably. An image forming apparatus comprising the rotation mechanism according to any one of claims 1 to 10 or the transfer device according to claim 12.

Images