JP3737824B2 - Developing device and image forming apparatus - Google Patents

Description

  The present invention relates to various image forming apparatuses such as a copying machine, a facsimile apparatus, and a printer, and a developing device applied to the image forming apparatus.

  Conventionally, a developing device as described in Patent Document 1 is known. The developing device is applied to an image forming apparatus such as a copying machine or a facsimile machine. The developing device main body supplies toner to a photosensitive drum of the image forming device, and is detachably attached to the developing device main body. And a toner cartridge for supplying toner. A toner discharge port that can be opened and closed is provided at the bottom of the toner cartridge, while a toner receiving port corresponding to the toner discharge port is provided in the developing device main body, and the toner cartridge is attached to the developing device main body. By opening the toner discharge port, the toner in the toner cartridge is supplied to a predetermined circulation conveyance path formed in the main body of the developing device.

  The circulation conveyance path is formed in a groove shape with an open top surface extending in parallel with the axis of the photosensitive drum. The circulation conveyance path includes an outward conveyance path corresponding to the toner receiving port and a return conveyance path corresponding to the developing roller, and a spiral feeder in which spiral fins are provided around the fin axis is provided in each conveyance path. The toner is respectively mounted, and the toner is circulated and conveyed between the forward conveyance path and the backward conveyance path by rotation of the spiral feeder around the feeder axis.

  Then, the toner received from the toner cartridge through the toner receiving port to the forward conveyance path is moved by rotation around the feeder shaft of the spiral feeder, and is sent to the backward conveyance path at the downstream end of the forward conveyance path. The developer transferred to the return path is transported in the direction opposite to the forward path by the drive of the spiral feeder, and only the toner therein is supplied to the peripheral surface of the developing roller, and the remaining part is returned to the forward path at the downstream end. It is supposed to be.

In the developing device of Patent Document 1 having such a basic configuration, the conveyance capability is configured such that the conveyance capability is locally reduced downstream from the toner receiving port of the spiral feeder provided in the forward conveyance path. Is provided. This conveyance capability suppression part implement | achieves reduction of conveyance capability by making the diameter dimension of a spiral fin smaller than another part. Further, by providing such a conveyance capability suppression unit, toner stays on the upstream side of the conveyance capability suppression unit. Since the toner stays between the conveyance capacity suppressing portion and the toner receiving port, if there is sufficient toner in the developing device, the toner stays blocking the toner receiving port and the toner stays in the toner cartridge. Supply is limited. On the other hand, when the toner in the developing device is consumed and the amount of toner decreases, the retention of the toner also decreases, thereby creating a space between the toner retention portion and the toner receiving port. Therefore, the toner falls from the toner cartridge and is supplied into the developing device. When a sufficient amount of toner is supplied into the developing device, the toner stays again to block the toner receiving port, and the toner supply is restricted. Thus, the amount of toner supplied from the toner cartridge to the developing device is automatically adjusted according to the amount of toner in the developing device.
JP 2001-235933 A

However, in the developing device described in Patent Document 1, the above-described conveyance capability suppression unit is provided to retain the toner, thereby restricting the replenishment of the toner from the cartridge. In addition, when the toner is hardly consumed as in the case where the low density printing is continued for a long time, the shelf hanging may be a problem.

  The present invention has been made in view of such a situation, and is intended for a developing device including a conveyance capability suppressing unit, and is effective in causing a shelf hanging phenomenon in the vicinity of a toner receiving port in a developer circulation conveyance path. It is an object of the present invention to provide a developing device and an image forming apparatus that can be prevented.

The invention according to claim 1 is an apparatus main body that supplies the developer to the peripheral surface of the image carrier while conveying the circulation path while stirring the developer, and a developer that supplies the developer into the apparatus main body. And a developer receiving port for receiving the developer from the developer supplying unit provided on the apparatus main body, and the developer receiving port disposed in the circulation path. In the developing device comprising a conveying unit that conveys the developer received from the image forming unit and a developing roller disposed opposite to the image carrier, the circulation path is a front conveying path formed along the developing roller. And a rear conveyance path formed in parallel to the front conveyance path at a position where the developer is supplied from the developer receiving port, and the conveyance means conveys the developer by rotating around an axis. Also transported in the direction The front conveying path is equipped with a front conveying means and the rear conveying path is fitted with a rear conveying means, respectively, and the rear conveying means is configured to suppress the conveying ability locally. The developer receiving port is on the developer circulation path, and when the developer is introduced into the developing device through the developer receiving port, the developer receiving port is on the circulation path of the developer. The developer is provided at a position where the developer is lifted upward by the rotation of the rear conveying means .

According to such a configuration, the developer introduced into the developing device main body from the developer supply unit via the developer receiving port of the developing device main body has the developer receiving port that passes through the developer receiving port. When the developer is introduced into the developing device, the developer is disposed at a position where the developer is lifted upward by the rotation of the rear conveying means, so that it is always conveyed in the axial direction by the conveying means immediately below the developer receiving port. Therefore, there is no inconvenience that a shelf is formed.

  According to a second aspect of the present invention, in the first aspect of the present invention, the conveying capacity suppressing portion is formed by attaching a rib member to the rear conveying means.

  According to such a configuration, the conveyance capability of the rear conveyance unit is reduced due to the presence of the rib member in the conveyance capability suppression unit.

  According to a third aspect of the present invention, in the invention according to the first or second aspect, the conveyance capacity suppressing portion is configured such that the diameter dimension of the rear conveyance means is set smaller than the diameter dimension of the rear conveyance means of the other part. It is characterized by being formed.

  According to such a configuration, if the diameter dimension of the rear conveying means is small, the propulsive force is reduced by that amount, so that the conveying force of the rear conveying means is reduced in the conveying capacity suppressing portion.

According to a fourth aspect of the present invention, in the first aspect of the invention, the rear conveying means includes a feeder shaft and a spiral fin formed in a spiral shape around the feeder shaft. The developer comprises a spiral feeder that conveys the developer in a predetermined conveyance direction by integral rotation around the feeder shaft, and the developer receiving port is on the developer circulation path and is developed through the developer receiving port. When the developer is introduced into the developing device, the developer is provided at a position where the developer is lifted upward by rotation of the spiral fin.

The image forming apparatus according to claim 5, an apparatus main body that supplies the developer to the peripheral surface of the image carrier while conveying the circulation path while stirring the developer, and supplies the developer into the apparatus main body. A developer supply unit, and a developer receiving port for receiving the developer from the developer supply unit provided in the upper portion of the apparatus main body, and the developer disposed in the circulation path. A conveying unit configured to convey the developer received from the receiving port; and a developing roller disposed to face the image carrier. The circulation path includes a front conveying path formed along the developing roller; A rear conveyance path formed in parallel to the front conveyance path at a position where the developer is supplied from the developer receiving port, and the conveyance means rotates in the conveyance direction by rotating around the axis. To be transported towards The front conveying path is equipped with a front conveying means, and the rear conveying path is equipped with a rear conveying means, and the rear conveying means is configured to locally suppress the conveying capacity. The developer receiving port is provided on the circulation path of the developer, and when the developer is introduced into the developing device through the developer receiving port, the rear conveying unit is provided The developing device is provided at a position where the developer is lifted upward by the rotation, and a drive mechanism for driving the conveying means.

According to the first aspect of the present invention, the developer introduced into the developing device main body from the developer supply unit via the developer receiving port of the developing device main body has the developer receiving port. When the developer is introduced into the developing device through the position , the developer is always lifted up by the rotation of the rear conveying means, so that the shaft is always provided by the conveying means immediately below the developer receiving port. Since it is conveyed in the direction of the heart, it is possible to reliably prevent the occurrence of inconvenience such as the formation of a shelf.

  According to the second aspect of the present invention, since the conveyance capability suppressing portion is formed by attaching the rib member to the rear conveyance unit, the conveyance capability of the rear conveyance unit is reliably reduced while having a simple structure. This can contribute to the reduction of the device cost.

  According to the third aspect of the present invention, the conveyance capacity suppressing portion is formed by setting the diameter dimension of the rear conveyance means to be smaller than the diameter dimension of the rear conveyance means of the other part. The propulsive force is reduced by the smaller diameter dimension, which can reliably reduce the conveying force of the conveying capacity suppressing unit.

  According to the fourth aspect of the present invention, since the developer receiving port is provided at a position where the developer is lifted upward by the rotation of the spiral fin, the developer can hardly be suspended. .

  According to the fifth aspect of the present invention, it is possible to provide an image forming apparatus equipped with a developing device capable of effectively preventing the shelf hanging phenomenon.

  FIG. 1 is an exploded perspective view showing an embodiment of a developing device according to the present invention. 2 and 3 are side sectional views of the developing device shown in FIG. 1, FIG. 2 shows a state in which the toner cartridge is removed from the developing device main body, and FIG. 3 shows the toner cartridge in the developing device main body. Each of the attached states is shown. FIG. 4 is a cross-sectional view in plan view of the housing of the developing device main body. In these drawings, the XX direction is referred to as the width direction, and the YY direction is referred to as the front-rear direction. In particular, the -X direction is referred to as the left, the + X direction is referred to as the right, the -Y direction is referred to as the front, and the + Y direction is referred to as the rear. .

  First, as shown in FIG. 1, the developing device 10 includes a developing device adjacent to the photosensitive drum D to supply toner to the peripheral surface of the photosensitive drum (image carrier) D (FIGS. 2 and 3). The apparatus has a basic configuration including an apparatus body (apparatus body section) 20 and a toner cartridge (developer supply section) 70 that is detachably attached to the developing apparatus body 20 and replenishes toner.

  The developing device body 20 includes a housing 30 provided with a circulation conveyance path (circulation path) 301 for circulating and moving toner (developer) therein, a lid body 40 for closing an upper surface opening of the housing 30, and the lid body. A lid body side shutter member 50 attached to the lid body 40 so as to open and close a toner reception port (developer reception port) 44 formed on the lid body 40, and the lid body to which the lid body side shutter member 50 is attached. The developing device main body 20 is formed by fixing 40 to the housing 30.

  The housing 30 includes a pair of side plates 31 in the width direction, each of which has a substantially rhombus shape that is configured to be lowered toward the front, a front plate 32 laid between the front edge portions of the side plates 31, and the rear edge portion. A rear plate 33, and a lower edge portion of each side plate 31 and a transport portion 35 (FIG. 2) laid on the lower edge portion of the rear plate 33. A circulation conveyance path 301 that circulates and conveys toner is formed in a space surrounded by the side plates 31, the front plate 32, the rear plate 33, and the bottom plate 35, and a pair of spiral feeders (conveyance) is formed in the circulation conveyance path 301. Means) 60 is mounted.

  The circulation conveyance path 301 includes a front conveyance path 302 that is long in the width direction formed in the front, and a rear conveyance path 303 that is formed behind the front conveyance path 302 in parallel with the front conveyance path 302. In addition, the spiral feeder 60 includes a front spiral feeder 61 mounted on the front transport path 302 and a rear spiral feeder 62 mounted on the rear transport path 303. As shown in FIG. 2, the bottom 35 of the circulation conveyance path 301 has an arcuate front conveyance path-side bottom plate 351 in a cross-sectional view corresponding to the front conveyance path 302 and an arc-shaped in a cross-sectional view corresponding to the rear conveyance path 303. A rear conveyance path side bottom plate 352 is provided.

  The front and rear spiral feeders 61 and 62 include a feeder shaft 63 installed between the pair of side plates 31 in the circulation conveyance path 301 and spiral fins 64 formed in a spiral shape around the feeder shaft 63. Thus, the toner loaded in the circulation conveyance path 301 can be circulated and conveyed by the integral rotation of the spiral fin 64 around the feeder shaft 63.

In the present embodiment, the spiral fins 64 of the front spiral feeder 61 form a so-called counterclockwise spiral that moves forward by turning counterclockwise when viewed from the end face of the feeder shaft 63, whereas The spiral fins 64 of the spiral feeder 62 form a so-called clockwise spiral that moves forward by turning clockwise when viewed from the end face of the feeder shaft 63. Therefore, when the front spiral feeder 61 rotates counterclockwise around the feeder shaft 63, the toner positioned in the front conveyance path 302 is conveyed to the left, whereas the rear spiral feeder 62 counteracts around the feeder shaft 63. When you rotate clockwise,
The toner in the rear conveyance path 303 is conveyed to the right.

  Further, a partition wall 34 is provided between the front and rear transport paths 302 and 303, and the left and right end portions of the partition wall 34 are formed by cutting out the left and right ends. A communication passage 304 that connects the passages 302 and 303 is provided. Therefore, when the front and rear spiral feeders 61 and 62 rotate counterclockwise around the feeder shaft 63, the toner in the circulation conveyance path 301 is conveyed to the front conveyance path 302 and the rear conveyance path via the left and right communication paths 304. It is circulated and conveyed counterclockwise with the path 303.

  As shown in FIGS. 2 and 3, a roller shaft 65 is installed between the pair of side plates 31 at a position in front of the front conveyance path 302, and the developing roller can rotate integrally around the roller shaft 65. 66 is pivotally supported. The front conveyance path 302 and the portion where the developing roller 66 is provided are in communication with each other over substantially the entire length in the width direction, and the developing roller 66 has a circumferential surface of the front photosensitive drum D. The installation position is set so as to face the peripheral surface. Therefore, the toner being conveyed through the front conveyance path 302 is supplied to the circumferential surface of the photosensitive drum D via the developing roller 66, thereby forming a toner image on the circumferential surface of the photosensitive drum D. .

  The lid body 40 includes a flat lid body 41 and a standing wall 42 extending in the width direction and erected at the center position in the front-rear direction of the lid body 41. The lid body 41 is set to have a plan dimension slightly larger than the opening of the upper surface of the housing 30, so that the upper surface of the circulation conveyance path 301 is closed in a state where the lid body 41 is placed on the upper surface of the housing 30. It is like that. A shutter mounting portion 43 for mounting the lid-side shutter member 50 is provided at a substantially central portion in the width direction behind the standing wall 42 in the lid body 41. The shutter mounting portion 43 is provided with a toner receiving port 44 for loading toner from the toner cartridge 70 into the housing 30. The lid-side shutter member 50 is for opening and closing the toner receiving port 44.

  As shown in FIGS. 2 and 3, the toner receiving port 44 is provided so as to face the upstream side in the rotational direction of the rear spiral feeder 62 in a state where the lid 40 is mounted on the housing 30. In the present embodiment, the rear spiral feeder 62 rotates counterclockwise around the feeder shaft 63, and thus a toner receiving port 44 is provided on the upstream side in the rotational direction.

  Therefore, the toner supplied into the rear conveyance path 303 through the toner receiving port 44 is first guided by the rotation of the spiral fin 64 and moves upward from the rear to the front of the spiral fin 64. Thereafter, the toner is guided toward the counterclockwise rotation around the feeder shaft 63 of the spiral fin 64 and is conveyed toward the right side (the back side of the paper surface in FIGS. 2 and 3).

  The lid-side shutter member 50 includes a shutter plate 51 corresponding to the toner receiving port 44 of the lid 40 and a pair of protrusions 52 provided on both sides in the width direction of the shutter plate 51 and extending in the front-rear direction. It is configured. The shutter plate 51 has a planar dimension sufficient to block the toner receiving port 44. Further, the rear end edges of the pair of protrusions 52 are each provided with an inclined surface 53 set to be lowered toward the rear. These inclined surfaces 53 are for moving the lid-side shutter member 50 forward by interference with the bottom of the toner cartridge 70 when the toner cartridge 70 is mounted on the developing device main body 20. The toner receiving port 44 is opened by the forward movement of the plate 51.

  Incidentally, as shown in FIG. 3, the toner cartridge 70 is pressed rearward by a coil spring 45 that is a biasing means in a state where the toner cartridge 70 is mounted on the developing device main body 20, thereby mounting the toner cartridge 70 on the developing device main body 20. Is made to be stable.

  The lid-side shutter member 50 is urged rearward by an urging force of an urging means such as a coil spring (not shown). Accordingly, when the toner cartridge 70 is not attached to the developing device main body 20, the toner receiving port 44 is closed by the shutter plate 51, while when the toner cartridge 70 is attached to the developing device main body 20, the lid The body-side shutter member 50 moves forward against the urging force of the urging means when the inclined surface 53 is pressed against the lower portion of the toner cartridge 70, thereby opening the toner receiving port 44. .

  As shown in FIG. 1, the toner cartridge 70 includes a cartridge main body 71 in which toner is loaded, and a cover body 78 that closes the upper surface opening of the cartridge main body 71. On the upper edge of the cartridge main body 71, an annular main body side flange portion 710 projecting outward is provided. On the cover body 78, the lid side corresponding to the main body side flange portion 710 is provided. A flange portion 780 is provided, and the flange portions 710 and 780 are fixed to each other by a welding process in a state where the toner is loaded in the cartridge main body 71, so that the toner cartridge 70 loaded with toner is finished. It has become.

  The cartridge body 71 has a left-right width dimension set slightly shorter than an inner dimension between the pair of side plates 31 in the housing 30 of the developing device body 20, and a front-rear width dimension of the cartridge body 71 and the lid 30 of the housing 30. It is set slightly shorter than the inner dimension between the body 40 and the standing wall 42, so that it is above the circulating conveyance path 301 in the housing 30 and is surrounded by the side plate 31, the rear plate 33 and the standing wall 42. The cartridge mounting space 305 is removable.

  As shown in FIG. 2, the cartridge main body 71 has a bottom plate 72 formed in a double-hump shape in a side view. That is, the bottom plate 72 includes a front arc bottom plate 721 corresponding to the shutter mounting portion 43 of the lid 40 and a rear arc bottom plate 722 formed behind the front arc bottom plate 721.

  At the lowermost position of the front arc bottom plate 721, a toner discharge port 73 formed so as to face the toner receiving port 44 of the lid 40 is provided, and the toner cartridge 70 is mounted in the housing 30 (see FIG. 3), the toner in the toner cartridge 70 is supplied into the housing 30 through the toner discharge port 73 and the toner receiving port 44 of the lid 40.

  Above the rear arc bottom plate 722, a stirring member 75 provided between the pair of side plates 74 is provided along the center of curvature of the rear arc bottom plate 722. The stirring member 75 includes a shaft member 751 that is rotatably installed between the pair of side plates 74 so as to be rotatable around an axis, and stirring fins 752 that project radially from the peripheral surface of the shaft member 751. Yes. The agitation fin 752 is made of a synthetic resin sheet, and the agitation member 75 rotates around the axis in the clockwise direction in FIG. 3 by driving a drive motor (not shown), so that the toner on the rear arc bottom plate 722 is removed. It scrapes off and supplies it toward the front circular arc bottom plate 721.

Above the front arc bottom plate 721, a spiral rod 76 laid between a pair of side plates 74 along the center of curvature of the front arc bottom plate 721, and a cartridge-side shutter member externally fitted to the spiral rod 76 77. The spiral rod 76 rotates in synchronization with the stirring member 75, so that the toner fed from the rear arc bottom plate 722 to the front arc bottom plate 721 is transported toward the toner discharge port 73, and the spiral setting direction and rotation are performed. Direction is set.

  The cartridge-side shutter member 77 is formed by a cylindrical body that is rotatably fitted around the spiral rod 76, and has an arc shutter portion 771 that closes the toner discharge port 73, and a counterclockwise side of the arc shutter portion 771. A long hole 772 that is long in the left-right width direction (direction perpendicular to the paper surface of FIG. 2) corresponding to the toner discharge port 73 that is provided adjacent to the edge of the toner is provided adjacent to the long hole 772 in the counterclockwise direction. And a circular arc wall 773. An opening 774 for supplying the toner fed by the stirring member 75 to the spiral rod 76 is formed between the circumferential edge portions of the arc shutter portion 771 and the arc wall 773 in the circumferential direction.

  The cartridge-side shutter member 77 can be changed in posture between the toner discharge port closing posture shown in FIG. 2 and the toner discharge port opening posture shown in FIG. Is provided with a posture changing operation member 80 for performing a posture changing operation on the cartridge side shutter member 77.

  As shown in FIG. 2, the posture changing operation member 80 includes an operation disk 81 mounted on the outer side of the side plate 31 so as to be rotatable around a substantially center of curvature of the arc bottom plate 36 of the cartridge mounting space 305, and the operation circle. A posture changing member 82 that changes the posture of the cartridge side shutter member 77 between the toner discharge port closing posture and the opening posture linked to the rotation around the rotation center of the plate 81 is configured. The operation disc 81 is provided with an operating rod 811 that protrudes radially outward from the outer peripheral surface, and meshing teeth 812 are provided on the peripheral surface substantially opposite to the operating rod 811. ing.

  The posture changing member 82 includes a semicircular portion 821 whose lower portion is formed in a semicircular shape, and a rectangular portion 822 that is integrally formed on the upper portion of the semicircular portion 821 but is rectangular. The posture changing member 82 is pivotally supported on the inner side of the right side plate 31 of the housing 30 so that the center of curvature of the semicircular portion 821 is concentric with the spiral rod 76 so as to be rotatable around an unillustrated axis. Is attached to the housing 30.

  In such a posture changing member 82, the spiral rod 76 is recessed on the inner surface side from the edge of the rectangular portion 822 facing the semicircular portion 821 toward the center of curvature of the semicircular portion 821. A fitting groove 83 into which the right end portion is fitted is provided. At the center of curvature of the fitting groove 83, a locking projection 831 is provided projecting radially outward from the center of curvature. On the right end of the cartridge-side shutter member 77, A not-illustrated locking groove that fits around the locking protrusion 831 is provided.

  As shown in FIG. 2, the toner cartridge 70 with the cartridge-side shutter member 77 set in the toner discharge port closing posture is set in the housing 30 with the posture change member 82 set in the standing posture as shown in FIG. 2. By mounting the cartridge in the cartridge mounting space 305, the locking groove is fitted on the locking projection 831.

  In this state, if the operation disc 81 is rotated counterclockwise by the operation of the operation rod 811 (see the operation rod 811 indicated by a two-dot chain line in FIG. 2), this rotation is changed in posture through the meshing teeth 812. When the posture changing member 82 is transmitted to the member 82 and rotated in the clockwise direction around the center of curvature of the posture changing member 82 by this, the posture changing member 82 changes its posture to a recumbent posture as shown by a two-dot chain line in FIG. By rotating the cartridge side shutter member 77 in the clockwise direction via the locking protrusion 831, the cartridge side shutter member 77 has a toner discharge port in which the long hole 772 faces the toner discharge port 73 as shown in FIG. 3. The posture is set to the open posture.

  In the present invention, as shown in FIG. 4, the rear spiral feeder 62 is provided with a conveyance capacity suppressing portion 67 on the downstream side of the toner receiving port 44. FIG. 5 is a perspective view showing an embodiment of the conveyance capacity suppressing unit 67. As shown in FIG. 5, the conveyance capability suppressing portion 67 is configured to include a plurality of circumferentially suppressing rods (rib members) 671 attached in parallel to the feeder shaft 63 at the peripheral edge of the spiral fin 64. In the present embodiment, four suppression rods 671 are provided at an equal pitch in the circumferential direction. However, the number of suppression rods 671 is not limited to four, and may be three or less. It may be 5 or more.

  By providing such a conveyance capacity suppressing portion 67 on the downstream side of the toner receiving port 44 in the rear spiral feeder 62, the spiral fin 64 rotates the counterclockwise direction around the axis of the feeder shaft 63 (see FIG. 5). When the toner conveyed to the right) reaches the conveyance capacity suppression unit 67, it becomes difficult to move forward because it is obstructed by the suppression rod 671, so that the toner stays on the upstream side of the conveyance capacity suppression unit 67. . Therefore, when the toner is replenished and the toner amount is increased, the staying toner acts so as to block the toner receiving port 44, and further toner replenishment is suppressed. When the toner is consumed and the amount of staying toner decreases, a gap is formed between the toner staying portion and the toner receiving port 44, and the toner is replenished in this gap.

  As described above in detail, the developing device 10 of the present invention includes the developing device main body 20 that supplies toner to the peripheral surface of the photosensitive drum D while transporting the circulating transport path 301 while stirring the toner, and the developing device main body. The toner cartridge 70 is detachably mounted on the developing device main body 20 to supply toner into the toner cartridge 20. The toner cartridge 70 has a toner discharge port 73 for discharging the toner to a front arc bottom plate 721. On the other hand, the developing device main body 20 is provided with a toner receiving port 44 corresponding to the toner discharge port 73 at the upper portion thereof and following the circulation conveyance path 301. The toner reception port 44 is provided in the circulation conveyance path 301. A rear spiral feeder 62 is provided as a transport means for transporting toner including toner received from the rear spiral feeder 62. The toner receiving port 44 is configured to have a transport capability suppressing portion 67 configured to locally decrease the transport capability downstream of the receiving port 44, and the toner receiving port 44 is upstream of the rotational direction of the rear spiral feeder 62. Therefore, the toner introduced into the developing device main body from the toner cartridge 70 through the toner discharge port 73 and the toner receiving port 44 of the developing device main body is lifted upward by the spiral fin 64. become. Further, since the toner receiving port 44 is provided on the upstream side in the rotation direction of the rear spiral feeder 62, the staying toner is conveyed in the axial direction via the upstream wall (rear plate 33). It is difficult to be in a suspended state.

  On the other hand, when the toner receiving port 44 is provided on the downstream side in the rotation direction of the spiral feeder 60 (conventional technology), since the movement of the staying toner is small, the toner is compressed. However, there is a problem that a shelf is easily suspended when a high temperature environment in which toner fluidity deteriorates or low density printing with extremely low toner consumption is continued for a long time.

  In the above-described embodiment, since the conveyance capacity suppressing portion 67 is formed by attaching the suppression rod 671 to the spiral fin 64, the conveyance capacity of the spiral feeder 60 is ensured while having a simple structure. Therefore, it is possible to reduce the cost of the apparatus.

  The present invention is not limited to the above embodiment, and includes the following contents.

(1) In the above embodiment, a spiral fin 64 having a counterclockwise spiral is used as the front spiral feeder 61, while a spiral fin 64 having a clockwise spiral is adopted as the rear spiral feeder 62, thereby By rotating both the rear spiral feeders 61 and 62 in the same direction, the toner is circulated and conveyed along the circulation conveyance path 301. Instead of this, the front and rear spiral feeders 61 and 62 are rotated. The spiral fins 64 may be spirals in the same direction, and their rotational directions may be reversed. By doing so, the toner can be circulated and conveyed in the circulation conveyance path 301.

  (2) In the above embodiment, since the rotation direction of the rear spiral feeder 62 is counterclockwise in FIG. 3, the toner receiving port 44 is provided on the rear side of the rear conveyance path 303. The toner receiving port 44 is not limited to be provided on the rear side of the rear conveyance path 303. When the rotation direction of the rear spiral feeder 62 is clockwise, the toner reception port 44 is connected to the rear conveyance path 303. Provided on the front side. Thus, the toner receiving port 44 is provided on the upstream side in the rotational direction of the rear spiral feeder 62.

  (3) In the above embodiment, the conveyance capacity suppressing portion 67 is formed by attaching the suppression rod 671 to the peripheral edge of the spiral fin 64 in parallel with the feeder shaft 63. The suppressing portion 67 is not limited to the one formed by attaching the suppressing rod 671 to the spiral fin 64. For example, the diameter of the spiral fin 64 is made smaller than that of the other portion, and the toner is conveyed. Various measures can be adopted as long as they are troublesome.

  In order to confirm the effect of the present invention, for the acceleration test, a running process with a printing rate of 0% (a process in which the paper is passed through the photosensitive drum D in a state where no printing is performed) is continued for 2 hours. After the toner circulation state is stabilized, a running process for transferring the sheet to the paper with an image density of 5% is continued for 2 hours, and the amount of toner in the developing device main body 20 changes during the two hours. The effect confirmation test which measures was carried out. The model of the image forming apparatus used in this test was “FS-1010” manufactured by Kyocera Mita Corporation.

  Further, as a comparative example, when the spiral direction of the rear spiral feeder 62 is formed in the reverse direction and the rotation direction around the feeder shaft 63 is opposite to that of the embodiment (clockwise rotation) (that is, the toner receiving port 44 is rearward). The transition of the toner amount was measured when the spiral feeder 62 was set to be downstream in the rotation direction.

The test results are as shown in FIGS. FIG. 6 is a transition graph in which time (min) is set on the horizontal axis and the cumulative toner amount (g) supplied into the developing device body 20 is plotted on the vertical axis. FIG. 7 is a transition graph of FIG. 6 is a graph showing a transition of the toner amount (g) in the developing device main body 20 calculated based on the graph. 6 and 7, “♦” is an example and “■” is a comparative example. Also, the dotted line in FIG. 6 is a toner consumption cumulative line assuming that the toner is supplied as calculated.

  As shown in FIGS. 6 and 7, in the embodiment, the amount of toner in the developing device main body 20 changes substantially constant, whereby the toner is supplied from the developing device 10 to the photosensitive drum D in a stable state. You can see that. On the other hand, in the comparative example, the amount of toner in the developing device main body 20 varies greatly. This is considered to be caused by the fact that the toner shelves occur near the toner receiving port 44 in the rear spiral feeder 62.

1 is an exploded perspective view illustrating an embodiment of a developing device according to the present invention. FIG. 2 is a cross-sectional view of the developing device shown in FIG. 1 in a side view, showing a state in which the toner cartridge is removed from the developing device main body. FIG. 2 is a cross-sectional view of the developing device shown in FIG. 1 in a side view, showing a state in which a toner cartridge is mounted on the developing device main body. It is sectional drawing of the planar view of the housing of a developing device main body. It is a perspective view which shows one Embodiment of a conveyance capability suppression part. 6 is a graph showing a transition of an accumulated toner amount supplied to a developing device. 5 is a graph showing a change in toner amount in the developing device.

Explanation of symbols

10 Developing Device 20 Developing Device Body (Device Body)
30 Housing 301 Circulation conveyance path (circulation path)
302 Front conveyance path 303 Rear conveyance path 304 Communication path 305 Cartridge mounting space 31 Side plate 32 Front plate 33 Rear plate 34 Partition wall 40 Lid 41 Lid main body 42 Standing wall 43 Shutter mounting part 44 Toner inlet (developer inlet) )
45 Coil spring 50 Cover-side shutter member 51 Shutter plate 52 Projection 53 Inclined surface 60 Spiral feeder (conveying means)
61 Front Spiral Feeder 62 Rear Spiral Feeder 63 Feeder Shaft 64 Spiral Fin 65 Roller Shaft 66 Developing Roller 67 Conveyance Capacity Suppression Unit 671 Suppression Rod (Rib Member)
70 Toner cartridge (developer supply unit)
71 Cartridge body 710 Body side flange portion 72 Bottom plate 721 Front arc bottom plate 722 Back arc bottom plate 73 Toner discharge port 74 Side plate 75 Stirring member 751 Shaft member 752 Stirring fin 76 Spiral rod 77 Cartridge side shutter member 771 Arc shutter portion 772 Long hole 773 Arc Wall 774 Opening part 78 Cover body 780 Lid side flange part 80 Attitude change operation member 81 Operation disk 811 Operation rod 812 Engagement tooth 82 Attitude change member 821 Semicircular part 822 Rectangular part 83 Insertion groove 831 Locking protrusion D Photoconductor drum (Image carrier)

Claims (5)

An apparatus main body that supplies the developer to the circumferential surface of the image carrier while conveying the circulation path while stirring the developer, and a developer supply that supplies the developer into the apparatus main body. ,
In the apparatus main body, a developer receiving port that receives developer from the developer supply unit provided on the upper portion of the apparatus main body, and a transport that transports the developer that is arranged in the circulation path and is received from the developer receiving port And a developing device comprising a developing roller disposed opposite to the image carrier,
The circulation path includes a front conveyance path formed along the developing roller, and a rear conveyance path formed in parallel with the front conveyance path at a position where the developer is supplied from the developer receiving port.
The conveying means conveys the developer in the conveying direction by rotating around an axis, and a front conveying means is provided in the front conveying path, and a rear conveying means is provided in the rear conveying path, respectively. Being attached,
The rear conveying means is provided with a conveying capacity suppressing unit configured to suppress the conveying capacity locally,
The developer receiving port is on the developer circulation path, and when the developer is introduced into the developing device through the developer receiving port, the developer is moved upward by the rotation of the rear conveying unit. A developing device, wherein the developing device is provided at a lifted position .   The developing device according to claim 1, wherein the conveyance capacity suppressing unit is formed by attaching a rib member to the rear conveyance unit.   3. The developing device according to claim 1, wherein the conveyance capacity suppression unit is formed by setting a diameter dimension of the rear conveyance unit to be smaller than a diameter dimension of the rear conveyance unit of another portion. . The rear conveying means includes a feeder shaft and a spiral fin formed in a spiral shape around the feeder shaft, and the developer is rotated in a predetermined conveying direction by integral rotation of the spiral fin around the feeder shaft. It consists of a spiral feeder that conveys toward the
The developer receiving port is on the developer circulation path, and when the developer is introduced into the developing device through the developer receiving port, the developer is lifted upward by the rotation of the spiral fin. The developing device according to claim 1, wherein the developing device is provided at a predetermined position. An apparatus main body that supplies the developer to the circumferential surface of the image carrier while conveying the circulation path while stirring the developer, and a developer supply that supplies the developer into the apparatus main body. The apparatus main body is transported with a developer receiving port for receiving the developer from the developer supply unit provided on the apparatus main body, and a developer disposed in the circulation path and received from the developer receiving port. And a developing roller disposed opposite to the image carrier. The circulation path includes a front conveying path formed along the developing roller and a developer receiving port from the developer receiving port. A rear conveyance path formed in parallel with the front conveyance path at a position to receive supply, and the conveyance means conveys the developer in the conveyance direction by rotating around an axis, Forward transport in the front transport path A stage is provided with a rear conveying means on the rear conveying path, respectively, and the rear conveying means is provided with a conveying capacity suppressing portion configured to locally suppress the conveying capacity, The developer receiving port is on the developer circulation path, and when the developer is introduced into the developing device through the developer receiving port, the developer is moved upward by the rotation of the rear conveying unit. A developing device provided at a position to be lifted ;
An image forming apparatus comprising: a driving mechanism that drives the conveying unit.

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