JP2018163236A - Development apparatus, assembly, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress variations in conveyance amounts of developer in a conveyance direction on a supply path of a development apparatus.SOLUTION: A development apparatus 40 comprises: a casing 70 having an agitation path 72D formed at one side and a supply path 72C formed in parallel with the agitation path 72D at the other side; an agitation member 68 provided on the agitation path 72D; a supply member 66 provided on the supply path 72C; a partition plate 72E provided in the casing 70 for partitioning the agitation path 72D and the supply path 72C, and arranged so as to be sandwiched between an upstream communication path 72K and a downstream communication path 72L for causing the agitation path 72D to communicate with the supply path 72C; and a flow passage 80 provided on the partition plate 72E for causing the supply path 72C to communicate with the agitation path 72D.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a developing device, an assembly, and an image forming apparatus.

  A developing device described in Patent Document 1 is a developing device that includes a stirring member that conveys and stirs a developer, and a developer carrier, a developer supply tank that supplies the developer to the developer tank, and a trickle. A discharge mechanism of the type, and the conveyance path includes an upper conveyance path, a lower conveyance path, a first communication path that connects a downstream side of the upper conveyance path and an upstream side of the lower conveyance path, and a lower conveyance path A second communication path that connects the downstream side and the upstream side of the upper conveyance path, and includes a circulation path through which the developer circulates by the upper conveyance path, the first communication path, the lower conveyance path, and the second communication path. The discharge mechanism is disposed at the downstream end of the upper conveyance path, the bottom surface on the downstream side of the upper conveyance path is positioned above the bottom surface on the upstream side of the lower conveyance path, and the first communication path is in a horizontal plane. On the other hand, it is arranged obliquely downward.

JP 2009-198760 A

  An object of the present invention is to suppress variation in the transport amount in the developer transport direction, compared to a partition in which a partition plate separates a supply path and an agitation path from a lower end to an upper end in a supply path of a developing device. .

  The developing device according to claim 1 of the present invention includes a casing having a stirring path formed on one side, and a supply path formed side by side with the stirring path on the other side, and the stirring path An agitation member provided in the supply path, a supply member provided in the supply path, an upstream communication path provided in the housing, partitioning the agitation path and the supply path, and communicating the agitation path and the supply path And a partition plate disposed between the downstream communication path and a flow path provided above the partition plate and connecting the supply path and the stirring path.

  A developing device according to a second aspect of the present invention is the developing device according to the first aspect, wherein a plurality of the flow paths are arranged at intervals.

  The developing device according to a third aspect of the present invention is the developing device according to the second aspect, wherein the plurality of flow paths open from the upstream side to the downstream side in the developer conveying direction in the stirring path. The area becomes smaller in order.

  A developing device according to a fourth aspect of the present invention is the developing device according to the second or third aspect, wherein the stirring member includes a spiral blade and a plate-like member extending in the axial direction of the stirring member. The plurality of flow paths are arranged so as to partially or entirely face the plate-like member.

  The developing device according to a fifth aspect of the present invention is the developing device according to any one of the first to fourth aspects, wherein the stirring path is formed from a lower side surface of the partition plate. It further has a ridge protruding upward.

  The developing device according to a sixth aspect of the present invention is the developing device according to the fifth aspect, wherein the hook has a base portion connected to the partition plate and a tip portion protruding above the stirring path. The upstream side of the stirrer stirring path is inclined from the base portion toward the tip portion, from the upstream side toward the downstream side in the developer transport direction.

  An assembly according to a seventh aspect of the present invention develops an image carrier on which a latent image is formed and a latent image formed on the outer peripheral surface of the image carrier as a toner image. And the developing device according to any one of the above, and assembled so as to be interchangeable as a unit with respect to the main body of the image forming apparatus.

  According to an eighth aspect of the present invention, there is provided an image forming apparatus, a charging device that charges the outer peripheral surface of the image holding member, and a latent image on the outer peripheral surface of the image holding member that is charged by the charging device. A latent image forming apparatus that forms a latent image, a developing apparatus that develops the latent image as a toner image, and a transfer apparatus that transfers the toner image to a transfer target. , With.

  According to the configuration of the first aspect of the present invention, it is possible to suppress variation in the transport amount in the transport direction of the developer as compared with the partition plate separating the supply path and the stirring path from the lower end to the upper end.

  According to the configuration of the second aspect of the present invention, it is possible to suppress variation in the transport amount in the transport direction of the developer as compared with a single channel.

  According to the configuration of the third aspect of the present invention, it is possible to suppress variations in the transport amount in the transport direction of the developer, compared to a case where the opening areas of the plurality of flow paths are constant.

  According to the configuration of the fourth aspect of the present invention, the flow path has a variation in the transport amount in the developer transport direction as compared to the portion of the stirring member facing the portion where the plate-like member is not disposed. Can be suppressed.

  According to the configuration of the fifth aspect of the present invention, it is possible to suppress variation in the transport amount in the transport direction of the developer as compared with the case where the developer directly flows from the flow path into the stirring path.

  According to the configuration of the sixth aspect of the present invention, it is possible to suppress the variation in the transport amount in the transport direction of the developer as compared with the case where the upstream side of the ridge extends in the width direction of the stirring path.

  According to the configuration of the seventh aspect of the present invention, the unevenness of the toner image on the image holding member can be suppressed as compared with the case where the partition plate of the developing device partitions the supply path and the stirring path from the lower end to the upper end. it can.

  According to the configuration of the eighth aspect of the present invention, image unevenness in the output image can be suppressed as compared with the case where the developing device according to the first to sixth aspects is not used.

FIG. 2 is a plan view showing an overall configuration inside the developing device according to the first embodiment. FIG. 2 is a cross-sectional view taken along the line 2-2 of the developing device and the photoreceptor according to the first embodiment. (A) It is 3A-3A sectional drawing in the image development apparatus concerning 1st Embodiment. (B) It is 3B-3B sectional drawing in the image development apparatus concerning 1st Embodiment. 1 is a front view illustrating a schematic layout of an image forming apparatus using a developing device according to a first embodiment. FIG. 3 is a perspective view illustrating a main part of the developing device according to the first embodiment. It is a side view which shows the structure of the flow path of the partition plate which concerns on 1st Embodiment. It is a perspective view which shows the principal part of the developing device which concerns on 2nd Embodiment. It is a perspective view which shows the principal part of the image development apparatus of a comparative example.

<First Embodiment>
An example of the developing device and the image forming apparatus according to the first embodiment will be described with reference to FIGS. In addition, the arrow H shown in the figure indicates the vertical direction (vertical direction) of the apparatus, the arrow W indicates the width direction (horizontal direction) of the apparatus, and the arrow D indicates the depth direction (horizontal direction) of the apparatus. .

(Overall configuration of image forming apparatus)
As shown in FIG. 4, the image forming apparatus 10 according to the first embodiment includes a storage unit 14 that stores a sheet material P as a recording medium, and a transport that transports the sheet material P stored in the storage unit 14. Part 16 is provided.

  Further, the image forming apparatus 10 includes an image forming unit 20 that forms an image on the sheet material P conveyed by the conveying unit 16 from the storage unit 14 and a control unit 12 that controls each unit.

[Container]
The accommodating portion 14 includes an accommodating member 26 that can be pulled out from the apparatus main body 10 </ b> A of the image forming apparatus 10 toward the front side in the apparatus depth direction, and the sheet material P is stacked on the accommodating member 26.

  Further, the accommodating member 26 is provided with a delivery roll 30 that sends out the sheet material P stacked on the accommodating member 26 to a conveying path 28 that constitutes the conveying unit 16.

[Transport section]
The transport unit 16 includes a plurality of transport rolls (reference numerals omitted) that transport the sheet material P along the transport path 28 along which the sheet material P is transported.

(Image forming part)
The image forming unit 20 includes four image forming units 18Y, 18M, 18C, and 18K of yellow (Y), magenta (M), cyan (C), and black (K). In the following description, Y, M, C, and K may be omitted when there is no need to distinguish between Y, M, C, and K.

  Each color image forming unit 18 is detachable from the apparatus main body 10A. Here, the image forming unit 18 is an example of an assembly.

  Each color image forming unit 18 is provided with a photosensitive drum 36 that rotates in the direction of arrow B in the figure, and a charging member 38 that charges the surface of the photosensitive drum 36.

  Further, the image forming unit 18 develops the electrostatic latent image formed by irradiating the charged photosensitive drum 36 with exposure light and the exposure light and visualizes it as a toner image (development). ) Developing device 40.

  Further, the image forming unit 20 includes an endless endless belt 22 that circulates in the direction of arrow A in the figure, an auxiliary roll 52 around which the endless belt 22 is wound, a tension applying roll 54, and a drive roll 56. It has been.

  Further, the image forming unit 20 includes a primary transfer roll 44 that transfers the toner image formed by the image forming unit 18 of each color to the endless belt 22.

  Further, the image forming unit 20 includes a secondary transfer roll 46 that transfers the toner image transferred to the endless belt 22 to the sheet material P.

  The transfer device 32 includes the endless belt 22, the auxiliary roll 52, the tension applying roll 54, the drive roll 56, and the primary transfer roll 44.

  Further, the image forming unit 20 is provided with a fixing device 50 that heats and pressurizes the sheet material P to which the toner image is transferred, and fixes the toner image to the sheet material P.

(Operation of image forming apparatus)
In the image forming apparatus 10, an image is formed as follows.

  First, the charging member 38 of each color to which a voltage is applied uniformly charges the surface of the photosensitive drum 36 of each color at a predetermined potential.

  Subsequently, based on image data inputted from the outside, the exposure device 42 irradiates the surface of the charged photosensitive drum 36 with exposure light to form an electrostatic latent image.

Thereby, an electrostatic latent image corresponding to the data is formed on the surface of the photosensitive drum 36 of each color. Further, each color developing device 40 develops the electrostatic latent image and visualizes it as a toner image.
In addition, the toner images formed on the surface of the photosensitive drum 36 for each color are sequentially transferred to the endless belt 22 by the primary transfer roll 44. In this way, the endless belt 22 holds the toner image on the outer peripheral surface.

  Therefore, the sheet material P sent out from the accommodating member 26 to the transport path 28 by the sending roll 30 is sent out to the transfer position T where the endless belt 22 and the secondary transfer roll 46 come into contact with each other.

  At the transfer position T, the sheet material P is conveyed between the endless belt 22 and the secondary transfer roll 46, so that the toner image on the outer peripheral surface of the endless belt 22 is transferred to the sheet material P.

  Further, the toner image transferred to the surface of the sheet material P is fixed to the sheet material P by the fixing device 50. Then, the sheet material P on which the toner image is fixed is discharged to the outside of the apparatus main body 10A.

(Main part configuration)
Next, the developing device 40 will be described.

  Here, for terms defining each direction in the developing device, the front side (left side in the figure) of the depth direction of the device is the upstream side of the stirring path or the downstream side of the supply path, and the back side of the apparatus in the depth direction. (Right side in the figure) may be appropriately rephrased as the downstream side of the stirring path or the upstream side of the supply path.

  As shown in FIG. 2, the developing device 40 includes a housing 72, a developing roll 60 disposed to face the photosensitive drum 36, a supply auger 66 that supplies the developer G to the developing roll 60, and a developing And a stirring auger 68 for stirring the agent G.

  Here, the supply auger 66 is an example of a supply member, and the stirring auger 68 is an example of a stirring member.

  The developer G in the present embodiment is a two-component developer composed mainly of toner T and magnetic carrier particles (hereinafter “carrier C”).

[Case]
As shown in FIG. 2, the casing 72 is disposed next to the photosensitive drum 36, and an opening 72 </ b> A that opens the inside of the casing 72 is provided in a portion of the casing 72 that faces the photosensitive drum 36. Is formed extending in the depth direction of the apparatus.

  In the housing 72, on the opposite side of the photosensitive drum 36 across the opening 72A, a delivery path 72B in which the developing roll 60 is disposed extends in the apparatus depth direction.

  Further, in the casing 72, a supply path 72C in which the supply auger 66 is disposed is formed obliquely below the delivery path 72B so as to extend in the apparatus depth direction.

  In the housing 72, on the opposite side of the delivery path 72B across the supply path 72C, a stirring path 72D in which the stirring auger 68 is disposed extends in the apparatus depth direction.

  Further, in the housing 72, a partition plate 72E that partitions the supply path 72C and the stirring path 72D is formed between the supply path 72C and the stirring path 72D.

  In the casing 72, an upstream communication path 72K is formed adjacent to the end of the partition plate 72E in the apparatus depth direction, and is adjacent to the end of the partition plate 72E on the near side in the apparatus depth direction. Thus, a downstream side communication path 72L is formed.

  Further, as shown in FIGS. 1 and 3, in the casing 72, the stirring auger 68 extends from the upstream side (front side in the apparatus depth direction) to the downstream side (back side in the apparatus depth direction) of the stirring path 72D. Is arranged.

  The casing 72 is formed with a replenishment path 72F that is continuous to the upstream side of the agitation path 72D and replenishes the toner T and the carrier C to the agitation path 72D.

  In this configuration, the toner T and the carrier C supplied to the developing device 40 flow from the toner cartridge 48 into the supply path 72F through the supply port 72H.

  The replenishment path 72F extends further from the upstream side of the stirring path 72D to the front side in the apparatus depth direction, and on the side of an extension line (not shown) extending to the downstream side (front side in the apparatus depth direction) of the supply path 72C. It is formed by bending (see FIG. 1).

  The replenishment path 72F, which is bent and changed in the L shape in plan view, has a replenishment port 72H above the replenishment path 72F on the extended line side extending from the supply path 72C.

  The replenishing port 72H is connected to any one of the toner cartridges 48Y, 48M, 48C, and 48K corresponding to each color shown in FIG.

  Further, in the casing 72, a supply auger 66 is arranged from the upstream side (back side in the apparatus depth direction) to the downstream side (front side in the apparatus depth direction) of the supply path 72C with respect to the supply path 72C. Yes.

  Further, a discharge path 72G for discharging the developer G from the developing device 40 is formed continuously from the downstream side of the supply path 72C to the front side in the apparatus depth direction.

  In this configuration, the developer G discharged from the developing device 40 is discharged to the outside of the developing device 40 through the discharge port 72J.

  The discharge path 72G extends to the front of the supply path 72F, and has a discharge port 72J below the discharge path 72G (see FIG. 3B).

−Supply / stirring / partition plate−
The wall surfaces forming the supply path 72C and the stirring path 72D have a U-shaped cross section as shown in FIG.

  Further, the partition plate 72E extends obliquely upward as viewed from the apparatus depth direction, and includes a supply path 72C and a stirring path 72D except for a part on the back side in the apparatus depth direction and a part on the near side in the apparatus depth direction. It rises from the inner surface of the bottom wall 72M of the casing 72 so as to partition.

[Development roll]
As described above, the developing roll 60 is disposed in the delivery path 72B. As shown in FIG. 2, a gap (development gap) for transferring the developer G from the developing roll 60 to the photosensitive drum 36 is formed between the developing roll 60 and the photosensitive drum 36. .

  The developing roll 60 includes a magnet roll 60A having a circular cross section and a rotating sleeve 60B that covers the magnet roll 60A and rotates around the magnet roll 60A.

  The rotating sleeve 60B is rotated in a direction indicated by an arrow C (clockwise) in the drawing when a rotational force is transmitted from a driving source (not shown).

[Supply auger]
As described above, the supply auger 66 is disposed in the supply path 72C and the discharge path 72G (see FIG. 1).

  As shown in FIG. 1, the supply auger 66 includes a supply shaft 66A extending in the apparatus depth direction, a spiral supply blade 66B formed on the outer peripheral surface of the supply shaft 66A, and a spiral circulation blade. 66C and a spiral discharge blade 66D.

  Both ends of the supply shaft 66A are rotatably supported by the wall portion of the casing 72, and a gear (not shown) that transmits a rotational force from a drive source is fixed to one end of the supply shaft 66A. Has been. In the present embodiment, as an example, the outer diameter of the supply shaft 66A is 8 mm.

  The supply blade 66B is formed in a portion of the supply shaft 66A disposed in the supply path 72C.

  Further, the circulation blade 66C is formed in a portion of the supply shaft 66A between the supply path 72C and the discharge path 72G.

  The spiral winding direction of the circulation blade 66C is opposite to the spiral winding direction of the supply blade 66B, and the developer G conveyed through the supply path 72C acts in the direction of clogging on the downstream side of the supply path 72C. And it is made to flow into the downstream communication path 72L side.

  In the present embodiment, as an example, the outer diameter of the supply blade 66B is 16 mm, and the outer diameter of the circulation blade 66C is slightly larger than the outer diameter of the supply blade 66B.

  In this embodiment, the pitch of the supply blades 66B is 28 mm, and the pitch of the circulation blades 66C is smaller than that of the supply blades 66B.

  As shown in FIGS. 1 and 3B, the discharge blade 66D is formed in the portion of the supply shaft 66A disposed in the discharge path 72G.

  Specifically, the discharge blade 66D has a spiral winding direction similar to that of the supply blade 66B. In the present embodiment, as an example, the outer diameter of the spiral blade constituting the discharge blade 66D is 16 mm.

  In this configuration, the rotating supply auger 66 conveys the developer G in the supply path 72C while stirring from the upstream side to the downstream side of the supply path 72C, and supplies the developer G to the developing roll 60. Yes.

  Further, the developer G transported through the supply path 72C through the downstream communication path 72L disposed downstream of the supply path 72C is fed into the stirring path 72D by the supply blade 66B and the circulation blade 66C of the rotating supply auger 66. It is designed to be delivered to the stirring auger 68.

  At this time, at the inlet of the discharge path 72G continuous downstream of the supply path 72C, the excess developer G in the supply path 72C without being transferred to the stirring path 72D resists the clogging action of the circulation blade 66C. Then, it passes through the circulation blade 66C and flows into the discharge path 72G.

  The developer G that has flowed into the discharge path 72G is conveyed through the discharge path 72G by the discharge vanes 66D, and is discharged to the outside of the developing device 40 through the discharge port 72J.

[Stirring auger]
As described above, the stirring auger 68 is disposed in the stirring path 72D and the supply path 72F (see FIG. 1).

  The stirring auger 68 includes a stirring shaft 68A extending in the apparatus depth direction, a spiral stirring blade 68B, a spiral circulation blade 68C, and a spiral replenishment formed on the outer peripheral surface of the stirring shaft 68A. And a blade 68D.

  Here, the stirring blade 68B is an example of a spiral blade.

  Both ends of the stirring shaft 68A are rotatably supported by the wall portion of the casing 72, and a gear (not shown) for transmitting a rotational force from a driving source is fixed to one end of the stirring shaft 68A. Has been. In the present embodiment, as an example, the outer diameter of the stirring shaft 68A is 11 mm.

  The stirring blade 68B is formed at a portion of the stirring shaft 68A disposed in the stirring path 72D.

  The circulation blade 68C is formed so that a part of the circulation blade 68C faces the upstream communication path 72K that communicates with the supply path 72C at the portion of the stirring shaft 68A disposed on the downstream side of the stirring path 72D. The winding direction of the blade 68D is reversed.

  The replenishing blade 68D is formed in the same winding direction as the spiral winding direction of the stirring blade 68B at the portion of the stirring shaft 68A disposed in the replenishing passage 72F that is continuous upstream of the stirring passage 72D.

  The outer diameters of the stirring blade 68B and the replenishing blade 68D are the same.

  Further, the helical pitch of the replenishing blade 68D is smaller than the helical pitch of the stirring blade 68B.

  Further, the outer diameter of the circulation blade 68C is larger than the outer diameter of the stirring blade 68B.

  A part of the portion where the stirring blade 68B is formed is provided with a plurality of stirring auxiliary plates 68E along the axial direction of the stirring shaft 68A of the stirring auger 68. Here, the auxiliary stirring plate 68E is an example of a plate-like member.

  Each of the plurality of auxiliary stirring plates 68E is disposed between a part of the stirring blades 68B, for example, one pitch or two pitches.

  The height of the stirring auxiliary plate 68E from the surface of the stirring shaft 68A is set smaller than the height of the stirring blade 68B from the surface of the stirring shaft 68A, and the height of the stirring shaft 68A is viewed from the axial direction of the stirring shaft 68A. A plurality of auxiliary stirring plates 68E are arranged in the circumferential direction.

  As shown in FIG. 1, in this configuration, the stirring blade 68B of the rotating stirring auger 68 is delivered from the supply auger 66 through the developer G flowing into the stirring path 72D from the replenishment path 72F and the downstream communication path 72L. The developer G is conveyed while stirring.

  Specifically, the stirring blade 68B of the rotating stirring auger 68 conveys the developer G from the upstream side to the downstream side of the stirring path 72D while stirring the developer G.

  Further, the circulating blade 68C of the rotating stirring auger 68 acts to block the developer G conveyed by the stirring blade 68B and passes it to the supply auger 66 through the upstream communication path 72K. Yes.

  In this way, the developer G is circulated between the supply path 72C and the stirring path 72D (see the arrow in the figure).

[Partition plate and flow path]
As described above, the partition plate 72E is formed to rise from the inner surface of the bottom wall 72M of the housing 72 so as to partition the supply path 72C and the stirring path 72D. Here, the flow path, which is a main part, will be described in detail together with the partition plate 72E.

  As shown in FIGS. 1 and 5, the flow path 80 is disposed at the upper end portion 72E1 of the partition plate 72E at a portion sandwiched between the upstream communication path 72K adjacent to the partition plate 72E and the downstream communication path 72L. The upper end is formed in a notch shape having an opening.

  The flow path 80 connects the stirring path 72D and the supply path 72C below the upper end 72E1 of the partition plate 72E.

  In this embodiment, as shown in FIG. 6, the flow path 80 is arrange | positioned in three places at intervals from the upstream of the supply path 72C toward the downstream (arrow E in the figure).

  FIG. 6 is a side view of the partition plate 72E in which the flow path 80 is disposed at three positions, as viewed from the stirring path 72D side.

  The three flow paths 80 are arranged in order from the upstream communication path 72K into which the developer G stirred and conveyed in the stirring path 72D is fed into the supply path 72C in the direction E, in the order of the first flow path 80A and the second flow path. A path 80B and a third flow path 80C are provided.

  Each of the flow paths 80A, 80B, and 80C has a rectangular shape and has an opening area different from each other.

  The first flow path 80A is an opening having dimensions of width w1 and depth d1, the second flow path 80B is an opening having dimensions of width w2 and depth d2, and the third flow path 80C has a width of It is an opening having dimensions of w2 and depth d2.

  These dimensions are set to w1 <w2 <w3 and d1 <d2 <d3.

  That is, the width and depth of the opening of the first flow path 80A are set to be the smallest, and the width and depth of each opening are gradually increased toward the third flow path 80C.

  As shown in FIG. 2, each bottom surface 80b of each flow path 80 is at least above the upper end 66At on the vertical axis VL line passing through the axis of the supply shaft 66A in the supply shaft 66A of the supply auger 66, and , Located in a range below the upper end 72E1 of the partition plate 72E.

  In the present embodiment, as shown in FIG. 1, the first flow path 80 </ b> A does not face the stirring auxiliary plate 68 </ b> E provided on the stirring blade 68 </ b> B of the stirring auger 68.

  Further, the second flow path 80B and the third flow path 80C are arranged to face the stirring auxiliary plate 68E provided on the stirring blade 68B of the stirring auger 68.

  Further, in one channel 80 facing the stirring assisting plate 68E, a part or all of the width of the opening of the channel 80 is arranged to face the stirring assisting plate 68E.

  Specifically, as shown in FIG. 1, like the second flow path 80B and the third flow path 80C, the upstream end of the stirring path 72D of the flow path 80 is the stirring path of the stirring auxiliary plate 68E. It is preferable that it is located upstream from the upstream end of 72D.

  In addition, the downstream end of each flow path 80 in the stirring path 72D is opposite to the downstream end in the stirring path 72D of the stirring auxiliary plate 68E at the same position or slightly shifted upstream or downstream. It may be.

(Effects of main components)
Next, the operation of the developing device 40 will be described.

  Inside the casing 72 of the developing device 40, a rotating supply auger 66 and a rotating stirring auger 68 are provided between the supply path 72C and the stirring path 72D while stirring the developer G, as shown in FIG. Circulate (see arrow in the figure).

  When the developer G is stirred, the toner T in the developer G and the carrier C are rubbed, and the toner T is triboelectrically charged to a predetermined polarity.

  Then, as shown in FIG. 2, the rotating supply auger 66 supplies the developer G to the developing roll 60.

  The developer G supplied to the developing roll 60 is held in a state where a magnetic brush (not shown) is formed on the surface of the developing roll 60 by the magnetic force of the magnet roll 60A.

  The rotating sleeve 60B that rotates rotates conveys the developer G.

  The rotating sleeve 60B that rotates rotates conveys the developer G to a position facing the photosensitive drum 36.

  Then, the toner T contained in the developer G conveyed to a position facing the photosensitive drum 36 adheres to the electrostatic latent image formed on the photosensitive drum 36, and the electrostatic latent image is developed as a toner image. .

  In the developing device 40, the control unit 12 (see FIG. 4) receives information from the detection means (not shown) that the toner T in the developer G circulating between the supply path 72C and the stirring path 72D has decreased.

  The controller 12 causes the toner T contained in the toner cartridge 48 to flow into the supply path 72F through the supply port 72H together with the carrier C.

  The developer G in the developing device 40 is maintained in an amount necessary for development (a standard amount necessary in advance) while the toner T is appropriately replenished.

  However, the amount of the developer G to be replenished is not uniform every time, and the developer G including an excess amount may be replenished.

  Then, the liquid level of the developer G that is conveyed while being stirred in the stirring path 72D and flows into the supply path 72C from the upstream communication path 72K rises.

  Further, in the stirring path 72D, the developer G replenished with the toner T becomes insufficiently stirred, and a part of the developer G may flow into the supply path 72C as a lump (hereinafter referred to as “soft block”). .

As a result, the liquid surface of the developer G on the supply path 72 </ b> C is wavy in part.
The undulation of the liquid level is greater on the upstream communication path 72K side (upstream side of the supply path 72C) than on the downstream side communication path 72L side (downstream side of the supply path 72C).

  In the present embodiment, the opening areas of the first flow path 80A, the second flow path 80B, and the third flow path 80C are sequentially reduced from the upstream side to the downstream side of the stirring path 72D.

  When this is viewed from the supply path 72C side, the opening areas of the first flow path 80A, the second flow path 80B, and the third flow path 80C increase in order from the upstream side to the downstream side of the supply path 72C. Yes.

  That is, the first flow path 80A (width w1, depth d1) having a small opening area is formed in a portion where the corrugation of the developer G is large on the upstream communication path 72K side (upstream side of the supply path 72C) in the partition plate 72E. Has been placed.

  Since the liquid level is high at the portion where the liquid level of the developer G is large, the supply path is provided even if the opening area of the first flow path 80A is smaller than the opening areas of the other second flow path 80B and the third flow path 80C. The developer G on the 72C side can be returned to the stirring path 72D side.

  On the other hand, the third flow path 80C (width w3, depth) having a large opening area is formed in a portion where the undulation of the developer G on the downstream communication path 72L side (downstream of the supply path 72C) in the partition plate 72E is small. d3) is arranged.

  Since the liquid level is low at the portion where the undulation of the liquid level of the developer G is small, the opening area of the third flow path 80C is made larger than the opening areas of the other first flow path 80A and the second flow path 80B. The developer G on the supply path 72C side is returned to the stirring path 72D side.

  In this way, by making the heights of the bottom surfaces 80b of the respective flow paths 80 different from each other, the liquid level of the developer G transported through the supply path 72C changes from the upstream to the downstream of the supply path 72C. Can correspond to height.

  Further, the bottom surface 80b of each flow path 80 is at least above the upper end 66At on the vertical axis VL line passing through the axis of the supply shaft 66A in the supply shaft 66A of the supply auger 66, and the upper end of the partition plate 72E. It is located in the range below 72E1.

Thus, the developer G including not only the developer G conveyed through the supply path 72C but also the developed developer G returned from the surface of the photosensitive drum 36 to the supply path 72C is supplied to the flow path in the partition plate 72E. 80 can be secured in the supply path 72C at a position below the bottom surface 80b.
In other words, as long as the amount of the developer G conveyed through the supply path 72C is within the range of an appropriate amount necessary for development (a predetermined standard amount), the developer G on the supply path 72C side. Therefore, the height of the bottom surface 80b of the flow path 80 is set at a position where it is not returned to the stirring path 72D.

  Here, as shown in FIG. 8, in the developing device 400 according to the comparative example, the partition plate 720E has no flow path.

  Therefore, the developer G fed to the supply path 720C via the upstream communication path 720K on the downstream side (right side of the drawing) of the stirring path 720D is the downstream communication path 720L on the downstream side (left side of the drawing) of the supply path 720C. On the way to, it is transported without being reduced, including the surplus.

  As a result, the amount of the developer G in the entire region of the developing roller (not shown) in the apparatus depth direction remains non-uniform, the transfer amount of the developer G to the photosensitive drum (not shown) becomes unstable, and the sheet material P This causes problems such as unevenness in the formed image.

  As described above, in the comparative example without the flow path 80, the developer G in the supply path 720C has a non-uniform property and amount from the upstream side to the downstream side of the supply path 720C and is held on the developing roll. The amount and the amount transferred to the photosensitive drum vary.

  As a result, uneven development may occur in the image on the sheet material P.

  On the other hand, in the present embodiment, the flow path 80 is a developer whose bulk is increased above the upper end 66At of the supply shaft 66A of the supply auger 66 on the vertical axis VL line passing through the axis of the supply shaft 66A. A part of G is returned to the stirring path 72D in the middle of conveyance toward the downstream side communication path 72L.

  A part of the surplus amount of the developer G on the supply path 72C is returned to the agitation path 72D through the first flow path 80A, thereby reducing the amount of developer G conveyed at the position of the supply path 72C. The liquid level of the developer G is lowered, and the waviness of the liquid level is reduced.

  Thereby, compared with what the partition plate 72E partitions the supply path 72C and the stirring path 72D from a lower end to an upper end, the dispersion | variation in the conveyance amount in the conveyance direction of the developer G can be suppressed.

  Part or all of the excess amount of the developer G in the supply path 72C is returned to the stirring path 72D by the first flow path 80A, and the developer G conveyed through the supply path 72C continues to be in the downstream side communication path 72L. It is conveyed toward.

  The liquid level of the developer G may still remain, and the developer G returns to the stirring path 72D through the second flow path 80B disposed closer to the downstream communication path 72L than the first flow path 80A. Thus, the transport amount of the developer G at this position is reduced.

  Also in the third flow path 80C, if the transport amount of the developer G is larger than a predetermined amount, the surplus amount of the developer G is present in the stirring path 72D as in the first flow path 80A and the second flow path 80B. Returned.

  As a result, the transport amount in the transport direction of the developer G is settled in a certain range as compared with a single flow path 80, and variation in the transport amount in the transport direction of the developer G can be suppressed.

  Further, in the partition plate 72E, the opening areas of the first flow path 80A, the second flow path 80B, and the third flow path 80C are sequentially reduced from the upstream side to the downstream side of the stirring path 72D.

  Since the liquid level is high in the portion where the liquid level of the developer G is large, the supply is performed even if the opening area of the first flow path 80A is smaller than the opening areas of the other second flow path 80B and the third flow path 80C. The developer G on the path 72C side can be returned to the stirring path 72D side.

  On the other hand, since the liquid level is low at the portion where the undulation of the liquid level of the developer G is small, the opening area of the third flow path 80C is larger than the opening areas of the other first flow path 80A and the second flow path 80B. The developer G on the supply path 72C side is returned to the stirring path 72D side.

  Thereby, compared with the thing with the opening area of the some flow path 80 being constant, the dispersion | variation in the conveyance amount in the conveyance direction of the developer G can be suppressed.

  Further, as shown in FIG. 1, a plurality of auxiliary stirring plates 68E are provided along the axial direction of the stirring shaft 68A of the stirring auger 68 at a part of the portion where the stirring blade 68B is formed.

  The second flow path 80B and the third flow path 80C provided in the partition plate 72E are disposed so as to face the stirring auxiliary plate 68E provided in the stirring blade 68B of the stirring auger 68.

  Specifically, as in the second flow path 80B and the third flow path 80C, the upstream ends of the stirring paths 72D of the flow paths 80B and 80C are upstream of the stirring path 72D of the stirring auxiliary plate 68E. It is located on the upstream side of the end of the.

  The auxiliary stirring plate 68E has an action of strongly stirring the developer G conveyed while being stirred in the stirring path 72D in the rotation direction of the stirring shaft 68A, and the occurrence of a soft block of the developer G is suppressed.

  Thereby, compared with what the flow path 80 is facing the part where the stirring auxiliary plate 68E is not arrange | positioned of the stirring member 68, the dispersion | variation in the conveyance amount in the conveyance direction of the developer G can be suppressed. .

  Thus, by returning a part of the developer G on the supply path 72C side to the stirring path 72D, variation in the amount of the developer G conveyed in the region from the upstream side to the downstream side of the supply path 72C is suppressed. The

  Thereby, the amount of the developer G held on the developing roll 60 is stabilized over the entire area of the developing roll 60 in the apparatus depth direction.

  Further, since the developing device 40 and the photosensitive drum 36 constitute the image forming unit 18 as a unit, the developing unit 40 and the photosensitive drum 36 can be replaced as a unit with respect to the apparatus main body 10A of the image forming apparatus.

  The image forming unit 18 can suppress unevenness of the toner image on the image holding member as compared with the case where the partition plate of the developing device partitions the supply path and the stirring path from the lower end to the upper end.

  In the image forming apparatus 10, the amount of the developer G transferred from the developing roll 60 to the photosensitive drum 36 is stable over the entire area of the photosensitive drum 36 in the apparatus depth direction. The print density of the image is stable, and the occurrence of uneven development can be suppressed.

  As a result, it is possible to suppress image unevenness such as color streaks in the output image, as compared with a case where the developing device 40 according to the present embodiment is not used.

  Further, the developer G returned from the supply path 72C to the stirring path 72D promotes the stirring ability of the developer G conveyed while being stirred in the stirring path 72D, and the occurrence of a soft block of the developer G is suppressed. The variation in the properties of the developer G flowing into the supply path 72C is suppressed.

  Further, by suppressing the undulation of the liquid surface of the developer G, cloud contamination in the apparatus is reduced.

  On the other hand, the developing device 40 according to this embodiment has a configuration in which the partition plate 72E includes the flow path 80, thereby suppressing variation in the amount of the developer G conveyed in the supply path 72C.

Second Embodiment
An example of the developing device according to the second embodiment of the present invention will be described mainly with reference to FIG. In addition, about 2nd Embodiment, the same code | symbol is used about the part which is common in 1st Embodiment, and a different part is mainly demonstrated.

  The developing device 40 according to the second embodiment is provided with a ridge 90 corresponding to the flow path 80.

  The eaves 90 is provided so as to protrude on the stirring path 72D from the stirring path 72D side below the flow path 80 in the partition plate 72E.

  The flange 90 includes a base portion 90A, a distal end portion 90B, an upper surface 90D, and a lower surface, and the base portion 90A has a plate shape having a size larger than that of the distal end portion 90B.

  Of the sides connecting the base portion 90A and the distal end portion 90B, the upstream side 90C in the conveyance direction of the developer G in the stirring path 72D is directed from the base portion 90A toward the distal end portion 90B in the width direction of the stirring path 72D. The developer G is inclined downstream in the conveying direction.

  In the present embodiment, the size of the base portion 90A of each ridge 90 corresponds to w1 to w3 that are the width of the opening of the flow path, and the size of the tip portion 90B is w = 0.

  Moreover, the bowl 90 has a length equivalent to the width of the stirring path 72D.

  The upper surface 90D of the gutter 90 is connected to the side surface of the partition plate 72E on the stirring path 72D side in accordance with the height of the bottom surface 80b of the flow path 80.

  Further, the lower surface of the bowl 90 is not in contact with the stirring auger 68 disposed in the stirring path 72D.

[Operation in Second Embodiment]
Next, the operation of the developing device 40 in the second embodiment will be described.
In the developing device 40 according to the second embodiment, the actions of the developer G in the agitation, supply, and flow path are the same as those in the first embodiment.

  As shown in FIG. 7, the gutter 90 is provided so as to protrude on the stirring path 72D from the stirring path 72D side of the flow path 80 in the partition plate 72E.

  The surplus when the level of the developer G transported through the supply path 72C and the amount of replenishment are large is returned from the flow path 80 to the stirring path 72D through the upper surface 90D of the bowl 90.

  At this time, the developer G falls from the upper surface 90D of the bowl 90 to the stirring path 72D.

  As a result, the agitation of the developer G being agitated and conveyed in the agitation path 72D is improved, and the developer G at the time when the developer G is fed into the supply path 72C is suppressed from generating soft blocks, and the waviness of the liquid level is reduced. Is done.

  Thereby, it is possible to suppress variation in the transport amount of the developer G in the transport direction, compared to the case where the developer directly flows from the flow path 80 into the stirring path 72D.

  Further, among the edges connecting the base portion 90A and the distal end portion 90B, the flange 90 has an upstream side 90C in the conveying direction of the developer G in the stirring path 72D so that the developer G is directed from the base portion 90A toward the distal end portion 90B. Inclined from the upstream side to the downstream side in the transport direction.

  Since the side 90C is inclined from the upstream side to the downstream side in the conveyance direction of the developer G, the developer G corresponds to the shape of the side 90C on the upper surface 90D of the flange 90 from the base 90A. It falls in order to the stirring path 72D toward the part 90B.

  That is, the developer G that falls is dispersed and returned onto the developer G that is being stirred and conveyed over the entire width direction of the stirring path 72D.

  Thereby, the agitation property in the entire width direction of the developer G that is being agitated and conveyed in the agitation path 72D is improved, and the developer G at the time when the developer G is fed into the supply path 72C is suppressed from generating a soft block. The waving of is eased.

  As a result, a part of the developer G in the supply path 72C can be returned over the entire region in the width direction of the stirring path 72D while being conveyed toward the downstream side communication path 72L. The variation in the amount of developer G in can be suppressed.

  As a result, it is possible to suppress variation in the transport amount in the developer transport direction, compared to the case where the upstream side of the ridge extends in the width direction of the stirring path.

  Although the present invention has been described in detail with respect to specific embodiments, the present invention is not limited to such embodiments, and various other embodiments are possible within the scope of the present invention. It is clear to the contractor.

  For example, in the above-described embodiment, the flow path 80 is an opening in which the upper end portion 72E1 of the partition plate 72E is cut out, but may be an opening that penetrates the upper portion of the partition plate 72E without cutting out the upper end portion 72E1. .

Further, the bottom surface 80b of the flow path 80 is above the upper end 66At on the vertical axis VL line passing through the axis of the supply shaft 66A of the supply auger 66 and below the upper end portion 72E1 of the partition plate 72E. However, the present invention is not limited to this.
For example, the flow path 80 is appropriately determined in consideration of the type and printing performance of the image forming apparatus (printing resolution, printing speed, etc.), the properties of the developer G, the performance of the developing apparatus depending on the pitch and rotation speed of the auger used, and the like. The position of the bottom surface 80b may be set.

  Moreover, although the flow path 80 is three places, it is good also as one place or two places, and good also as four places or more.

  Further, the opening areas of the first flow path 80A, the second flow path 80B, and the third flow path 80C are made different, but the opening areas may be the same, and the width w of the opening is the same. The depth d may be varied, or the width w may be varied with the same depth d.

  In addition, a plurality of auxiliary stirring plates 68E are provided in a part of the part where the stirring blade 68B of the stirring member 68 is formed, but may be provided in a part corresponding to the entire stirring path 72D.

  Further, although the stirring auxiliary plate 68E is provided along the axial direction of the stirring shaft 68A of the stirring auger 68, the stirring auxiliary plate 68E may be bent, curved or inclined with respect to the axial direction of the stirring shaft 68A. The plate thickness can be arbitrarily set.

  In addition, although the stirring auxiliary plate 68E is described as a linear and rectangular plate-like member in FIGS. 1 and 5 to 7, it is bent or curved with respect to the radial direction of the stirring shaft 68A of the stirring auger 68. Or you may make it incline and the board thickness can be set arbitrarily.

  In addition, each of the plurality of auxiliary stirring plates 68E is arranged between one pitch or two pitches of the stirring blade 68B, but may be provided over three pitches or more of the stirring blade 68B. You may provide so that it may not contact the surface of the stirring blade 68B within 1 pitch.

  The height of the auxiliary stirring plate 68E from the surface of the stirring shaft 68A is set to be smaller than the height of the stirring blade 68B from the surface of the stirring shaft 68A. You may set to the same extent as the height from.

  Further, the plurality of stirring auxiliary plates 68E are arranged in the circumferential direction of the stirring shaft 68A when viewed from the axial direction of the stirring shaft 68A, but may be one.

  Further, the connection position of the flange 90 to the side surface of the partition plate 72E is set so that the height of the upper surface 90D of the flange 90 and the bottom surface 80b of the flow path 80 is matched, but the upper surface 90D is lower than the bottom surface 80b. They may be connected so as to have a step between the bottom surface 80b and the top surface 90D.

  In addition, the size of the base 90A of the ridge 90 is made to correspond to the width w of the flow path 80, but the dimensions do not necessarily have to be the same, and the base 90A of the ridge 90 is larger than the width w of the flow path 80. The dimensions may be large or small.

  Further, the positions of the ridge 90 and the flow path 80 in the transport direction of the developer G may be shifted in the transport direction.

  Moreover, although the protrusion form to the stirring path 72D of the bowl 90 is not particularly mentioned, the protruding form may be horizontal with respect to the stirring path 72D from the base portion 90A to the tip portion, or inclined in the vertical direction. Alternatively, it may be bent or curved.

  Further, although the image forming unit 18 as an assembly is configured to include the photosensitive drum 36, the developing device 40, the charging member 38, and the exposure device 42, the present invention is not limited thereto. The image forming unit 18 only needs to include at least the photosensitive drum 36 and the developing device 40, and may have a configuration different from that of the above embodiment.

  Further, the photosensitive drum 36 and the developing device 40 are not limited to an assembly like the image forming unit 18, and may be independent elements (single items).

  Further, the image forming apparatus 10 is not limited to the one having the image forming unit 18, and the photosensitive drum 36 and the developing device 40 may be independent.

10 Image forming apparatus 18 Image forming unit (an example of an assembly)
36 Photosensitive drum (an example of an image carrier)
40 Developing device 48 Toner cartridge 54 Secondary transfer roll 60 Developing roll (an example of rotating member)
66 Supply auger (an example of a supply member)
66A Supply shaft 66At Upper end 66B Supply blade 66C Circulation blade 66D Discharge blade 68 Stirring auger (an example of a stirring member)
68A Stirring shaft 68B Stirring blade 68C Circulating blade 68D Replenishment blade 68E Stirring auxiliary plate (an example of a plate member)
70 Housing 72C Supply path 72D Agitation path 72E Partition plate 72E1 Upper end 72F Supply path 72G Discharge path 72H Supply port 72J Discharge port 72K Upstream side communication path 72L Downstream side communication path 72M Bottom wall 80 Channel 80A First channel 80B First Two channels 80C Third channel 80b Bottom surface 90 庇 90A Base 90B Tip 90C Side 90D Upper surface w Width of opening (of channel) d Depth of opening of (channel) G Developer T Toner VL Vertical axis

Claims (8)

A housing having a stirring path formed on one side and a supply path formed side by side with the stirring path on the other side;
A stirring member provided in the stirring path;
A supply member provided in the supply path;
A partition plate that is provided in the casing and partitions the stirring path and the supply path, and is disposed between the upstream communication path and the downstream communication path that connect the stirring path and the supply path, and
A flow path provided at an upper portion of the partition plate and connecting the supply path and the stirring path;
A developing device.   The developing device according to claim 1, wherein a plurality of the flow paths are arranged at intervals.   The developing device according to claim 2, wherein the plurality of flow paths have an opening area that decreases in order from an upstream side to a downstream side in the developer conveyance direction in the stirring path. The stirring member has a spiral blade and a plate-like member extending in the axial direction of the stirring member,
The developing device according to claim 2, wherein a part or all of the plurality of flow paths are arranged to face the plate-like member.   5. The developing device according to claim 1, further comprising a ridge protruding above the stirring path from a lower side surface of the partition plate of the flow path.   The scissors have a base connected to the partition plate and a tip protruding above the stirring path, and an upstream side of the stirrer in the stirring path is downstream from the base toward the tip. The developing device according to claim 5, wherein the developing device is inclined to the side. An image carrier on which a latent image is formed;
The developing device according to any one of claims 1 to 6, wherein a latent image formed on an outer peripheral surface of the image carrier is developed as a toner image.
Including
An assembly assembled so as to be interchangeable with the image forming apparatus main body. An image carrier,
A charging device for charging the outer peripheral surface of the image carrier;
A latent image forming device that forms a latent image on the outer peripheral surface of the image carrier charged by the charging device;
The developing device according to any one of claims 1 to 6, wherein the latent image is developed as a toner image.
A transfer device for transferring the toner image to a transfer target;
An image forming apparatus.