JP2014038280A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of removing retention of a toner in a toner conveyance path with a simple configuration.SOLUTION: An image forming apparatus 100 includes a developing unit 3a that can be removably attached to an apparatus body, and a supply pipe 20 that has a toner conveyance path 20a for supplying toner to the developing unit 3a. The supply pipe 20 and the developing unit 3a are provided with a first contact part 20e and a second contact part 30, respectively, which come into contact with each other when the developing unit 3a is attached to the apparatus body; and when the first contact part 20e and the second contact part 30 come into contact with each other, the supply pipe 20 is oscillated.

Description

  The present invention relates to an image forming apparatus, and more particularly to an image forming apparatus provided with a supply pipe having a toner conveyance path for supplying toner to a developing unit.

  In an image forming apparatus using an electrophotographic system such as a copying machine, a printer, or a FAX, a powdered developer (hereinafter referred to as toner) is mainly used, and an electrostatic formed on an image carrier such as a photosensitive drum. In general, the latent image is visualized by toner in the developing unit, and the toner image is transferred onto a recording medium directly or via an intermediate transfer member, and then a fixing process is performed. In an image forming apparatus using toner, a toner transport path is provided to supply toner from a toner container (replenishment unit) to a developing unit.

  However, depending on the shape of the toner conveyance path, the fluidity of the toner, and the like, toner accumulation may occur in the toner conveyance path. In particular, when the toner conveyance path is bent (not straight), or when the toner conveyance path includes a portion for conveying the toner in the horizontal direction, toner accumulation tends to occur in the toner conveyance path.

  Therefore, Japanese Patent Laid-Open No. 2004-26883 discloses an image forming apparatus that includes a toner transport member (replenishment pipe) having a toner transport path and a rotating body that vibrates the toner transport member, and eliminates toner accumulation by vibrating the toner transport member. Is disclosed. In this image forming apparatus, the rotating body is configured to rotate in response to the rotational driving force of the stirring and conveying member that conveys the toner while stirring.

JP 2006-267945 A

  However, in the said patent document 1, in order to transmit the rotational drive force of a stirring conveyance member to a rotary body, a gear train is required. For this reason, there is a problem that the structure becomes complicated. In addition, although the above-mentioned patent document 1 describes that a dedicated drive source (for example, a motor) for driving the rotating body may be provided, in this case, a drive source, a drive circuit, wiring, and the like are separately required. become.

  SUMMARY An advantage of some aspects of the invention is that it provides an image forming apparatus capable of eliminating toner accumulation in a toner conveyance path with a simple configuration. That is.

  In order to achieve the above object, an image forming apparatus according to the present invention includes a developing unit that is detachable from the apparatus main body, and a replenishing pipe that has a toner transport path for supplying toner to the developing unit. The pipe and the development unit are respectively provided with a first contact portion and a second contact portion that come into contact with each other when the development unit is attached or detached, on sliding surfaces that slide when the development unit is attached to or detached from the apparatus main body. The supply pipe vibrates when the first contact portion and the second contact portion come into contact with each other.

  According to the present invention, the supply pipe and the development unit are provided with the first contact portion and the second contact portion that contact each other when the development unit is attached to and detached from the apparatus main body, respectively. When the contact portion and the second contact portion come into contact with each other, the supply pipe vibrates. Thus, the supply pipe can be vibrated when the developing unit is attached / detached, so that toner accumulation in the toner transport path can be eliminated. Further, since only the first contact portion and the second contact portion are provided on the supply pipe and the developing unit, respectively, it is possible to prevent the structure from becoming complicated.

1 is a cross-sectional view schematically showing the structure of an image forming apparatus according to an embodiment of the present invention. It is sectional drawing which showed the structure around the supply pipe of one Embodiment of this invention. It is the perspective view which showed the structure of the supply pipe of one Embodiment of this invention. FIG. 2 is a perspective view illustrating a structure around a supply pipe and a developing unit according to an embodiment of the present invention. FIG. 2 is a perspective view illustrating a structure around a supply pipe and a developing unit according to an embodiment of the present invention. FIG. 5 is a cross-sectional view illustrating a state in which toner accumulation occurs in a toner conveyance path of a supply pipe according to an embodiment of the present invention. It is the side view which showed the structure of the replenishment pipe and image development unit of one Embodiment of this invention. FIG. 6 is a side view illustrating a state where a first contact portion of a supply pipe according to an embodiment of the present invention is in contact with a second contact portion of a developing unit. FIG. 10 is a side view illustrating a state where the first contact portion of the supply pipe according to the embodiment of the present invention is in contact with the second contact portion of the developing unit and the first contact portion is lifted. It is sectional drawing which showed the state which the supply pipe of one Embodiment of this invention rotated in the C2 direction. FIG. 6 is a side view showing a state where a first contact portion of a supply pipe according to an embodiment of the present invention is in contact with a portion on a B direction side of a second contact portion of a developing unit. It is the perspective view which showed the structure of the replenishment pipe and image development unit of one Embodiment of this invention.

  Embodiments of the present invention will be described below with reference to the drawings.

  A structure of an image forming apparatus 100 according to an embodiment of the present invention will be described with reference to FIGS. In the main body of the image forming apparatus 100 (here, a color printer), four image forming portions Pa, Pb, Pc, and Pd are sequentially arranged from the upstream side in the transport direction (right side in FIG. 1). These image forming portions Pa to Pd are provided corresponding to images of four different colors (cyan, magenta, yellow, and black), and cyan, magenta, and yellow are respectively performed by charging, exposure, development, and transfer processes. And a black image are sequentially formed.

  These image forming units Pa to Pd are provided with photosensitive drums (image carriers) 1a, 1b, 1c and 1d for carrying visible images (toner images) of the respective colors, and further, driving means (FIG. 1), an intermediate transfer belt 8 that rotates clockwise in FIG. 1 is provided adjacent to each of the image forming portions Pa to Pd. The toner images formed on the photosensitive drums 1a to 1d are sequentially primary-transferred and superimposed on the intermediate transfer belt 8 that moves while contacting the photosensitive drums 1a to 1d. Thereafter, the toner image primarily transferred onto the intermediate transfer belt 8 is secondarily transferred onto a transfer paper P as an example of a recording medium by the action of the secondary transfer roller 9. Further, the transfer paper P on which the toner image is secondarily transferred is discharged from the main body of the image forming apparatus 100 after the toner image is fixed in the fixing unit 13. An image forming process for each of the photosensitive drums 1a to 1d is executed while rotating the photosensitive drums 1a to 1d counterclockwise in FIG.

  The transfer paper P on which the toner image is secondarily transferred is housed in a paper cassette 16 disposed at the lower part of the main body of the image forming apparatus 100, and is transferred to the secondary transfer roller via the paper feed roller 12a and the registration roller pair 12b. 9 and a nip portion between a later-described intermediate transfer belt 8 and a driving roller 11. A sheet made of dielectric resin is used for the intermediate transfer belt 8, and a (seamless) belt having no seam is mainly used. Further, a blade-like belt cleaner 19 for removing toner remaining on the surface of the intermediate transfer belt 8 is disposed on the downstream side of the secondary transfer roller 9.

  Next, the image forming units Pa to Pd will be described. There are chargers 2a, 2b, 2c, and 2d for charging the photosensitive drums 1a to 1d and image information on the photosensitive drums 1a to 1d around and below the photosensitive drums 1a to 1d that are rotatably arranged. The exposure device 5 for exposing the toner, the developing units 3a, 3b, 3c and 3d for forming toner images on the photosensitive drums 1a to 1d, and the developer (toner) remaining on the photosensitive drums 1a to 1d are removed. Cleaning parts 7a, 7b, 7c and 7d are provided.

  When image data is input from a host device such as a personal computer, first, the surfaces of the photosensitive drums 1a to 1d are uniformly charged by the chargers 2a to 2d, and then light is irradiated according to the image data by the exposure device 5. The electrostatic latent images corresponding to the image data are formed on the respective photosensitive drums 1a to 1d. Each of the developing units 3a to 3d is filled with a predetermined amount of a two-component developer containing toners of cyan, magenta, yellow, and black. In addition, when the ratio of the toner in the two-component developer filled in each of the developing units 3a to 3d falls below a specified value due to the formation of a toner image described later, the toner containers (replenishing units) 4a to 4d will be described later. The toner is supplied to each of the developing units 3a to 3d via the supply pipe 20. The toner in the developer is supplied onto the photosensitive drums 1a to 1d by the developing units 3a to 3d and electrostatically adheres to the electrostatic latent image formed by exposure from the exposure device 5. A toner image is formed.

  The primary transfer rollers 6a to 6d apply an electric field at a predetermined transfer voltage between the primary transfer rollers 6a to 6d and the photosensitive drums 1a to 1d, and cyan, magenta, yellow, and yellow on the photosensitive drums 1a to 1d. A black toner image is primarily transferred onto the intermediate transfer belt 8. These four color images are formed with a predetermined positional relationship predetermined for forming a predetermined full-color image. Thereafter, in preparation for the subsequent formation of a new electrostatic latent image, the toner remaining on the surfaces of the photosensitive drums 1a to 1d after the primary transfer is removed by the cleaning units 7a to 7d.

  The intermediate transfer belt 8 is stretched over an upstream driven roller 10 and a downstream drive roller 11, and the intermediate transfer belt 8 rotates clockwise as the drive roller 11 is rotated by a drive motor (not shown). When the rotation starts, the transfer paper P is conveyed from the registration roller pair 12b to the nip portion (secondary transfer nip portion) between the drive roller 11 and the secondary transfer roller 9 provided adjacent thereto at a predetermined timing. The full color image on the intermediate transfer belt 8 is secondarily transferred onto the transfer paper P. The transfer sheet P on which the toner image is secondarily transferred is conveyed to the fixing unit 13.

  The transfer paper P conveyed to the fixing unit 13 is heated and pressed by the fixing roller pair 13a to fix the toner image on the surface of the transfer paper P, and a predetermined full-color image is formed. The transfer paper P on which the full-color image is formed is distributed in the transport direction by the branching portion 14 that branches in a plurality of directions. When an image is formed on only one side of the transfer paper P, it is discharged as it is onto the discharge tray 17 by the discharge roller pair 15.

  On the other hand, when images are formed on both sides of the transfer paper P, a part of the transfer paper P that has passed through the fixing unit 13 is once protruded from the discharge roller pair 15 to the outside of the apparatus. Then, after the trailing edge of the transfer paper P has passed through the branch portion 14, the discharge roller pair 15 is rotated in the reverse direction and the transport direction of the branch portion 14 is switched. As a result, the transfer paper P is distributed from the rear end to the paper transport path 18 and is transported again to the secondary transfer nip portion with the image surface reversed. Then, the next toner image formed on the intermediate transfer belt 8 is secondarily transferred to the surface of the transfer paper P on which the image is not formed by the secondary transfer roller 9. The transfer paper P onto which the toner image has been secondarily transferred is conveyed to the fixing unit 13 where the toner image is fixed and then discharged onto the discharge tray 17.

  Next, the detailed structure of the replenishment pipe 20 for supplying toner to the developing unit 3a and the developing unit 3a will be described. 2 shows a cross section of the vicinity of the supply pipe 20 from the left side of FIG. Further, in the following description, the developing unit 3a disposed in the image forming unit Pa of FIG. 1 is illustrated, but the configuration of the developing units 3b to 3d disposed in the image forming units Pb to Pd is basically the same. Therefore, explanation is omitted.

  In the vicinity of the developing unit 3a, a supply pipe 20 (FIGS. 2 and 3) provided with a toner transport path 20a for supplying toner to the developing unit 3a is disposed. One replenishment pipe 20 is provided not only for the developing unit 3a but also for each of the developing units 3b to 3d. Further, as will be described later, as shown in FIGS. 4 and 5, the developing unit 3 a can be attached to and detached from the apparatus main body by sliding along the rail portion 41 of the apparatus main body (image forming apparatus 100 main body). It has become.

  In this embodiment, the image forming apparatus 100 is a color machine and is provided with an intermediate transfer belt 8. As shown in FIG. 1, the intermediate transfer belt 8 is disposed immediately above the developing unit 3 a, and the toner container 4 a is disposed above the intermediate transfer belt 8. Therefore, the replenishment pipe 20 for supplying toner from the toner container 4a to the developing unit 3a is connected to the vertical conveyance unit 21 extending in a substantially vertical direction and the vertical conveyance unit 21 as shown in FIGS. It is formed in a substantially L shape including a horizontal conveyance portion 22 extending in a substantially horizontal direction.

  As shown in FIG. 2, the vertical conveyance unit 21 is connected to a supply passage member 40 provided with a toner conveyance path 40a connected to the toner container 4a (see FIG. 1). A transport screw 23 for transporting toner is provided in the horizontal transport unit 22. The conveying screw 23 is connected to a drive source (not shown), and conveys toner from the vertical conveying unit 21 side to the leading end side (A direction) by rotating. Note that when the supply pipe 20 is formed in a substantially L shape including the vertical conveyance unit 21 and the horizontal conveyance unit 22, toner accumulation tends to occur at the inlet portion 20 b of the horizontal conveyance unit 22. This is because, as shown in FIG. 6, the toner T is hollowed only around the conveying screw 23 and may be in a so-called kamakura shape. In particular, this phenomenon is remarkable when the toner T falls in a large amount at once or when the fluidity of the toner T is lowered.

  Further, as shown in FIG. 2, a drop opening 22a for dropping the toner is formed at the front end side (A direction) of the horizontal transport unit 22, and a sliding door that opens and closes the drop opening 22a. 24 is provided.

  The replenishment pipe 20 is configured to vibrate when the developing unit 3a is attached to and detached from the apparatus main body, as will be described later. Specifically, as shown in FIG. 3, the supply pipe 20 is provided with a rotating shaft portion 20c. The rotating shaft portion 20c is rotatably supported by a bearing (not shown) of the apparatus main body. Thereby, the replenishment pipe 20 is rotatable around the rotation shaft portion 20c (rotation shaft O). This rotation shaft portion 20c (rotation shaft O) is located at a portion near the B direction (on the side opposite to the first contact portion 20e described later) on the side surface perpendicular to the rotation shaft O of the vertical transport portion 21. Has been placed. In addition, the rotation shaft portion 20 c (the rotation shaft O) is disposed in a portion closer to the lower side than the central portion of the vertical conveyance portion 21.

  As shown in FIG. 2, a spring member 42 (urging member) that urges the vertical conveyance unit 21 in the A direction is provided on the outer side surface of the vertical conveyance unit 21 on the B direction side. Thereby, the replenishment pipe 20 is applied with a force to rotate in the C1 direction. In addition, the vertical conveyance unit 21 is provided with a regulation unit 20d (see FIG. 3) that regulates the rotation of the supply pipe 20 in the C1 direction. For this reason, while the vertical conveyance part 21 is arrange | positioned so that it may extend in a substantially vertical direction, the horizontal conveyance part 22 is arrange | positioned so that it may extend in a substantially horizontal direction. Note that each of the rotating shaft portion 20c and the regulating portion 20d is provided on both the near side and the far side with respect to the paper surface of FIG.

  Here, as shown in FIG. 7, a first abutting portion 20e is provided at the tip of the horizontal conveying portion 22 of the replenishing pipe 20, and a second side of the developing unit 3a has a second portion. A contact portion 30 is provided. The first contact portion 20e and the second contact portion 30 are respectively provided on sliding surfaces of the supply pipe 20 and the development unit 3a that slide when the development unit 3a is attached to and detached from the apparatus main body. ing. A plurality of (for example, three) second contact portions 30 are arranged along the attaching / detaching direction (A direction, B direction) of the developing unit 3a. The first contact portion 20e and the second contact portion 30 are provided so as to contact each other when the developing unit 3a is attached to and detached from the apparatus main body.

  When the first contact portion 20e contacts the second contact portion 30 as shown in FIG. 8, the first contact portion 20e is lifted upward as shown in FIG. 9, and the supply pipe as shown in FIG. 20 rotates by a few degrees in the C2 direction. When the first contact portion 20e exceeds the second contact portion 30, the supply pipe 20 is rotated (returned) in the C1 direction by the spring member 42. The rotation in the C2 direction and the C1 direction is repeated as many times as the first contact portion 20e and the second contact portion 30 contact each other. That is, the replenishment pipe 20 vibrates by the number of the second contact portions 30.

  Further, the replenishment pipe 20 is formed by resin molding, for example, and the horizontal conveyance unit 22 may warp downward toward the tip. Since the first abutting portion 20e is formed with an inclined surface, in this case, the first abutting portion 20e of the horizontal conveying portion 22 is formed by the second abutting portion 30 of the developing unit 3a as shown in FIG. It abuts against the B direction side and lifts upward. For this reason, it is possible to prevent the developing unit 3a from being attached to the apparatus main body.

  When the developing unit 3a is further moved (inserted) along the rail portion 41 in the B direction, the tip 32 (see FIG. 7) of the developing unit 3a is inserted into the claw portion 24a (see FIG. 7) of the door 24 of the supply pipe 20. ) Abut. As a result, the door 24 slides in the direction B, and the drop opening 22a (see FIG. 2) opens. At substantially the same time, the tip convex portion 20f (see FIG. 7) of the supply pipe 20 comes into contact with the sliding door 33 (see FIG. 7) of the developing unit 3a. Thereby, the door 33 slides and the supply port 34 (refer FIG. 12) opens. Then, the replenishing port 34 of the developing unit 3a is disposed below the drop port 22a (see FIG. 2) of the replenishing pipe 20 with the developing unit 3a mounted on the apparatus main body. At this time, the positioning boss 35 (see FIG. 5) of the developing unit 3a is fitted into the positioning hole 43 (see FIG. 5) on the apparatus main body side, and the developing unit 3a is positioned. The doors 24 and 33 are biased by a spring member or the like (not shown), and the drop port 22a and the supply port 34 are closed when the developing unit 3a is removed from the apparatus main body.

  In the present embodiment, as described above, the supply pipe 20 and the development unit 3a have the first contact portion 20e and the second contact portion 30 that contact each other when the development unit 3a is attached to and detached from the apparatus main body. The replenishment pipe 20 vibrates when the first contact portion 20e and the second contact portion 30 are in contact with each other. As a result, the supply pipe 20 can be vibrated when the developing unit 3a is attached or detached (for example, during maintenance), so that toner accumulation in the toner transport path 20a can be eliminated. Further, since only the first contact portion 20e and the second contact portion 30 are provided in the supply pipe 20 and the developing unit 3a, respectively, it is possible to prevent the structure from becoming complicated.

  Further, as described above, the supply pipe 20 vibrates by rotating about a predetermined rotation shaft portion 20c (rotation shaft O). Thereby, the supply pipe 20 can be vibrated easily.

  Further, as described above, the spring member 42 that biases the supply pipe 20 in the direction opposite to the direction in which the supply pipe 20 rotates when the first contact part 20e and the second contact part 30 contact each other. Is provided. Thereby, the supply pipe 20 can be vibrated easily.

  In addition, as described above, a plurality of the second contact portions 30 are arranged along the attaching / detaching direction (A direction, B direction) of the developing unit 3a. Thereby, the replenishment pipe 20 can be vibrated by the number of the second contact portions 30 when the developing unit 3a is attached or detached.

  Further, as described above, when the replenishment pipe 20 is formed in a substantially L shape including the vertical conveyance portion 21 extending in the substantially vertical direction and the horizontal conveyance portion 22 extending in the substantially horizontal direction, the inside of the toner conveyance path 20a. In particular, toner accumulation tends to occur. For this reason, it is particularly effective to apply the present invention when the supply pipe 20 is formed in an L-shape including the vertical conveyance unit 21 and the horizontal conveyance unit 22.

  Further, as described above, the first contact portion 20 e is provided in the vicinity of the front end portion of the horizontal conveyance portion 22. Accordingly, the first contact portion 20e can be easily brought into contact with the second contact portion 30, and the supply pipe 20 can be rotated with a small force. Further, even when the horizontal conveyance unit 22 is warped downward, the tip of the horizontal conveyance unit 22 can be lifted, and it is possible to prevent the development unit 3a from being attached to the apparatus main body.

  In addition, as described above, the rotation shaft portion 20c (the rotation shaft O) is located on a portion of the side surface perpendicular to the rotation shaft O of the vertical transport portion 21 that is closer to the side opposite to the first contact portion 20e. Has been placed. Accordingly, the rotation shaft portion 20c (the rotation shaft O) can be separated from the portion where the toner accumulation is likely to occur (inlet portion 20b), and thus the movement amount (runout width) of the portion where the toner accumulation is likely to occur (inlet portion 20b). ) Can be reduced.

  Further, as described above, the rotation shaft portion 20 c (the rotation shaft O) is disposed at a portion closer to the lower side than the vertical central portion of the vertical conveyance portion 21. Thereby, when the replenishment pipe 20 rotates, it can suppress that the front-end | tip of the horizontal conveyance part 22 comes out too much to the A direction side.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and further includes all modifications within the meaning and scope equivalent to the scope of claims for patent.

  For example, in the above embodiment, the example in which the present invention is applied to the tandem type color image forming apparatus as shown in FIG. 1 has been described, but the present invention is not limited to this. Needless to say, the present invention can be applied to various image forming apparatuses having a supply pipe for supplying toner, such as rotary color copiers and printers, monochrome copiers, monochrome printers, digital multifunction peripherals, and facsimiles.

  Moreover, although the example which formed the replenishment pipe in the L shape was shown in the said embodiment, the replenishment pipe may be formed in shapes other than L shape (for example, straight shape).

  In the above-described embodiment, an example in which a plurality of second contact portions are arranged along the attaching / detaching direction of the developing unit has been described. However, a plurality of first contact portions may be arranged along the attaching / detaching direction of the developing unit. A plurality of both the first contact portion and the second contact portion may be arranged.

  In the above embodiment, the supply pipe is biased in the A direction (C1 direction) by the spring member, and the supply pipe rotates in the C2 direction when the first contact portion and the second contact portion contact each other. Although an example of the configuration is shown, the present invention is not limited to this. The supply pipe may be urged in the B direction (C2 direction) by the spring member so that the supply pipe rotates in the C1 direction when the first contact portion and the second contact portion contact each other. Good.

  In the above embodiment, an example in which the rotation shaft portion (rotation shaft) is disposed on the lower portion of the vertical conveyance portion has been described. However, the rotation shaft portion (rotation shaft) is disposed on the upper side of the vertical conveyance portion. You may arrange in a part.

  In the above embodiment, the supply pipe vibrates by rotating. However, the supply pipe may vibrate without rotating.

3a to 3d Developing unit 20 Supply pipe 20a Toner transport path 20e First contact portion 21 Vertical transport portion 22 Horizontal transport portion 30 Second contact portion 42 Spring member 100 Image forming apparatus O Rotating shaft

Claims (8)

A development unit detachable from the apparatus main body;
A replenishment pipe having a toner transport path for supplying toner to the developing unit;
With
The replenishment pipe and the developing unit include a first contact portion and a second contact portion that are in contact with each other when the developing unit is attached / detached to a sliding surface that slides when the developing unit is attached / detached to / from the apparatus main body. There are separate contact points,
The image forming apparatus, wherein the supply pipe vibrates when the first contact portion and the second contact portion contact each other.   The image forming apparatus according to claim 1, wherein the supply pipe vibrates by rotating about a predetermined rotation axis.   An urging member for urging the supply pipe is provided in a direction opposite to a direction in which the supply pipe rotates when the first contact part and the second contact part contact each other. The image forming apparatus according to claim 2.   4. The apparatus according to claim 1, wherein at least one of the first contact portion and the second contact portion is arranged in a plurality along the attaching / detaching direction of the developing unit. 5. Image forming apparatus.   The said supply pipe is formed in the substantially L shape containing the vertical conveyance part extended in a substantially vertical direction, and the horizontal conveyance part connected to the said vertical conveyance part, and extended in a substantially horizontal direction. 5. The image forming apparatus according to any one of 4 above.   The image forming apparatus according to claim 5, wherein the first contact portion is provided in a vicinity of a front end portion of the horizontal conveyance portion. The supply pipe vibrates by rotating about a predetermined rotation axis,
The rotation shaft is arranged in a portion of the side surface perpendicular to the rotation shaft of the vertical transport unit that is closer to the side opposite to the first contact portion. The image forming apparatus described in 1. The supply pipe vibrates by rotating about a predetermined rotation axis,
8. The image forming apparatus according to claim 5, wherein the rotation shaft is disposed in a portion closer to a lower side than a central portion in the vertical direction of the vertical conveyance unit.

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