JP5146221B2 - Developing device and image forming apparatus - Google Patents

Description

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

  As a conventional developing device, there is known a developing device in which the developer is replaced little by little in order to stabilize the amount of developer and charging performance in the developing device (see, for example, Patent Document 1).

The developing device supplies a developer to the photosensitive drum to develop an electrostatic latent image on the photosensitive drum, a supply auger for supplying the developer to the developing roller, and a horizontal surface with respect to the supply auger. A stirring auger that is provided at a position and supplies developer to the supply auger, a developer carrier, a drive auger that rotates the supply auger and the stirring auger in the same direction, and a lower end of the supply auger. And a developer replenishing port provided above the end of the stirring auger.
JP 2001-265098 A

  An object of the present invention is to provide a developing device and an image forming apparatus capable of smoothly supplying a developer.

[1] A developer holding body for holding a developer, first and second rotating shafts arranged on the same axis and rotatably provided independently from each other, and the first rotating shaft. The first conveying blade that conveys the developer to the developer holding body along a predetermined axial direction and the developer formed on the second rotating shaft and replenished from the outside of the apparatus A first conveying member having a first replenishing blade for conveying the developer, and a second conveying member for conveying the developer conveyed by the first replenishing blade to the first conveying blade. A second conveying member having blades and the first rotation shaft so that the first conveying blade moves in the order of the gravity direction downward, the side on which the developer holding member is disposed, and the direction of gravity upward. While rotating, the first supply blade is moved downward in the direction of gravity on the second rotation shaft. Serial second transfer members arranged side developing device and a drive unit for rotating to move in the order of gravity upward.

[2] The developing device according to [1], wherein the driving unit rotationally drives the second transport member in the same direction as the rotation direction of the first rotation shaft.

[3] In the above [1], the first conveyance blade and the first supply blade have different developer conveyance directions at the boundary between the first rotation shaft and the second rotation shaft. Development device.

[4] An image forming apparatus comprising the developing device according to any one of [1] to [3].

  According to the first and fourth aspects of the present invention, compared to the case of using a transport member that does not have two rotation shafts that can rotate independently from each other, the supply of the developer to the developer holding member Thus, it is possible to provide a developing device that is excellent in terms of compatibility with the delivery of the developer to other transport members.

  According to the second aspect of the present invention, it is possible to smoothly circulate the developer from the second conveying member to the first conveying member.

  According to the third aspect of the present invention, the developer can be smoothly supplied.

  A developing device according to an embodiment of the present invention includes a developer holding body for holding a developer, first and second rotating shafts arranged on the same axis and rotatably provided independently of each other, Formed on the first rotating shaft, formed on the second rotating shaft, and a first transport blade that transports the developer so as to be supplied to the developer holding body along a predetermined axial direction. A first conveying member having a first replenishing blade that conveys the developer replenished from the outside of the apparatus, and the developer conveyed by the first replenishing blade to the first conveying blade. A second conveying member having a second conveying blade for conveying toward the first conveying shaft, and a first conveying blade below the first rotating shaft in the direction of gravity, the side on which the developer holding member is disposed, the direction of gravity Rotation drive so as to move in the upper order, and the second rotation shaft to the first replenishment Blade comprises gravity downward, the second conveying member is arranged side and a drive unit for rotating to move in the order of gravity upward.

  The blades of the first and second conveying members may be provided spirally on the rotation shaft, or a plurality of feed plates may be provided inclined on the rotation shaft.

  As the developer, a two-component developer composed of a magnetic carrier and a toner mainly composed of a resin may be used, or a one-component developer composed of a toner mainly composed of a resin may be used. Alternatively, a two-component developer may be used as the developer circulating between the first and second conveying blades, and only the toner may be replenished from the outside.

  In the above configuration, when the developer reaches a high temperature (for example, 40 to 50 ° C.) due to a change in the usage environment of the developing device, the flowability of the developer decreases, and the first supply blade is changed to the second supply blade. In some cases, the developer accumulates on the developer path. Therefore, by rotating the first replenishment blade in the direction opposite to the rotation direction of the first transport blade, even if the developer is accumulated, the pile of accumulated developer can be broken from the side surface direction. Become.

  FIG. 1 is a cross-sectional view taken along the line AA of FIG. 2 showing a main configuration of the developing device according to the embodiment of the present invention. FIG. 2 is a top view of the main configuration of the developing device according to the embodiment of the present invention. It is sectional drawing seen from the direction.

  The developing device 1 includes a housing 2 that stores a developer. The developer 2 is supplied to the photosensitive drum 100, which is an example of an image holding member, in the housing 2, so that the electrostatic latent image on the photosensitive drum 100 is supplied. A developing roller 3 that develops an image; a supply auger 4 that is an example of a first conveying member that supplies developer to the developing roller 3; and a second that agitates the developer and supplies developer to the supply auger 4 A stirring auger 5, which is an example of a conveying member, is disposed in parallel to the photosensitive drum 100.

  As shown in FIG. 2, the developing roller 3, the supply auger 4, and the stirring auger 5 are rotatably supported by the housing 2 by a bearing 7. Further, in FIG. 2 of the developing roller 3, the supply auger 4 and the stirring auger 5, at the right shaft end, there are one idler gear 8D and 8E between the gears 8A to 8C and the gears 8A to 8C, respectively. Each is attached.

Next, an aspect of a supply auger having a first rotating shaft and a second rotating shaft according to the present embodiment will be described.
As shown in FIG. 2, the supply auger 4 is supported by a support portion 6 that supports the shaft end so that the first rotation shaft 40 </ b> A and the second rotation shaft 40 </ b> B can rotate independently of each other on the same axis. The developing roller, the first rotating shaft 40A of the supply auger 4 and the stirring auger 5 are rotated to the right in FIG. 1 by the rotational force from the main motor 9A which is an example of the drive unit, and the second rotating shaft of the supply auger 4 40B is configured to rotate counterclockwise in FIG. 1 by the rotational force from the sub motor 9B which is an example of the drive unit. The detailed configuration of the support portion 6 will be described later. As the motors 9A and 9B, known motors such as a DC motor and a pulse motor can be used. In this embodiment, the main motor 9A and the sub motor 9B are given as an example of the drive unit, and the first rotary shaft 40A and the second rotary shaft 40B of the supply-gar 4 are driven using different motors. However, it is possible to provide a driving force from the stirring auger 5 by providing a gear (not shown) at the left shaft end in FIG. 2, and the first rotation shaft 40A and the second rotation can be received only by the main motor 9A. The shaft 40B may be rotationally driven.

  The developing roller 3 includes a developing sleeve that is rotationally driven while maintaining a predetermined interval between the developing roller 3 and the peripheral surface of the photosensitive drum 100, and a magnet roller that is provided inside the developing sleeve and has a plurality of magnetic poles disposed therein. And a developer adjusted to a certain thickness by a not-illustrated cutting blade is carried on the surface.

(housing)
The housing 2 includes a main housing 2A that is accommodated so that the developer supplied to the developing roller 3 circulates, and a sub-housing 2B that accommodates the developer supplied to the main housing 2A. The main housing 2A is provided with a developing opening 20 so that the developing roller 3 is exposed to the photosensitive drum 100 side. The sub-housing 2B is provided with a replenishing port 21 for replenishing developer into the housing 2 from a developer cartridge (not shown) and a discharge port 22 for discharging excess developer to the outside. A partition wall 23 that partitions the supply auger 4 and the stirring auger 5 is disposed inside the housing 2. The partition wall 23 has a passage port 23a through which the developer is circulated from the supply auger 4 side to the stirring auger 5 side, and a passage through which the developer is circulated from the stirring auger 5 side to the supply auger 4 side. A port 23b and a communication port 23c for supplying the developer supplied from the supply port 21 from the supply auger 4 side to the stirring auger 5 side are provided. The main housing 2A and the sub housing 2B are made of, for example, a resin such as ABS resin, polyacetal resin, polystyrene resin, or a metal such as aluminum.

(Supply auger)
The supply auger 4 has, on the first rotating shaft 40A, a transport blade 41 as an example of the first transport blade in order from the right side in FIG. 2, and a passage port 23a among the developer transported by the transport blade 41. The circulation vane 42 that conveys the developer passing through the circulation port 23 a so as to circulate through the passage port 23 a and the discharge blade that conveys the developer over the circulation blade 42 toward the discharge port 22. 43, and a supply blade 44, which is an example of the first supply blade, is provided on the second rotating shaft 40B. The supply auger 4 is integrally formed from, for example, a resin such as ABS resin, polycarbonate resin, polyacetal resin, or polystyrene resin, or a metal such as aluminum.

The conveying blade 41 is spirally provided in the region of the first rotation shaft 40A facing the developing roller 3, and the axial direction of the first rotation shaft 40A determined in advance by the rotation of the first rotation shaft 40A. The developer is supplied to the developing roller 3 while conveying the developer to F ₁ . By rotating the first rotating shaft 40A so that the conveying blade 41 moves in the order of the gravity direction lower side, the side where the developing roller 3 is disposed, and the upper side of the gravity direction, the developer is moved to the first rotating shaft 40A. In contrast, the toner is conveyed to the side where the developing roller 3 is disposed.

The circulation blade 42 is composed of a blade opposite to the conveyance blade 41, and is provided in a spiral shape on the rotary shaft 40 with a predetermined interval between the circulation blade 42 and a predetermined value. by acting the developer having been conveyed in the axial direction F _1, which is to push back by the rotation of the first rotation shaft 40A, the developer direction F ₂ indicated by the arrow in FIG. _2, i.e. from the supply auger 4 side While circulating to the stirring auger 5 side through the communication port 23a, the excess developer whose developer augment amount on the supply auger 4 side exceeds a certain amount is discharged to the left in FIG.

  The discharge vane 43 is composed of vanes in the same direction as the conveyance vane 41, is lower in height than the conveyance vane 41, is spirally provided on the rotating shaft 40 at a small pitch, and the circulation vane 42 is Excess developer that has been overcome is discharged to the discharge port 22.

  The replenishment blade 44 is formed of a blade opposite in direction to the discharge blade 43 and is spirally provided on the second rotating shaft 40B, and sends the developer replenished from the replenishing port 21 to the stirring auger 5 side. Further, a flat small blade 44 a is provided inside the replenishment blade 44 for smooth feeding.

(Stirring auger)
The stirring auger 5 is disposed below the supply auger 4 at a predetermined angle (10 to 50 degrees, or 20 to 40 degrees, specifically 30 degrees) θ from the horizontal direction. Further, the stirring auger 5 has a rotation shaft 50, and developer is supplied onto the rotation shaft 50 in order from the left side in FIG. Of the developer blade 52 that is received and conveyed toward the supply auger 4, and the developer conveyed by the conveyance blade 52, the developer that has passed through the passage port 23b is circulated through the passage port 23b. Circulating blades 53 are provided to be conveyed. The stirring auger 5 is integrally formed from, for example, a resin such as ABS resin, polycarbonate resin, polyacetal resin, or polystyrene resin, or a metal such as aluminum. In the present embodiment, the agitation auger in which the replenishment blade 51, the transport blade 52, and the circulation blade 53 are integrally formed is used, but the replenishment blade 51 and the transport blade 52 are formed separately. The developer may be supplied to the developing roller 3 using three or more augers.

The replenishment blade 51 is composed of a blade opposite to the conveyance blade 41 of the supply auger 4 and is provided in a spiral shape on the rotating shaft 50. The developer replenished from the replenishing port 21 side is indicated by an arrow in FIG. direction _{F 5} shown, that is conveyed in the conveying vane 52.

The conveying blade 52 is composed of a blade opposite to the conveying blade 41 of the supply auger 4 and is spirally provided in the central region of the rotating shaft 50, and the developer conveyed by the replenishing blade 51, or the developer that has been circulated through the communicating opening 23a from the supply auger 4 side, conveyed in the axial direction F ₁ opposite axial F ₃ which is predetermined by the rotation of the rotary shaft 50. By rotating the rotary shaft 50 so that the conveying blade 52 moves in the order of the gravity direction lower side, the side on which the supply auger 4 is disposed, and the upper side of the gravity direction, the developer is moved relative to the rotary shaft 50 of the stirring auger 5. Then, the feed auger 4 is transported biased toward the side where it is disposed.

Circulation vane 53, the conveying blade 52 is provided spirally on the rotary shaft 50 is composed of a blade in the opposite direction, so as to push back the developer having been conveyed in the axial direction F ₃ by the transfer blade 52 By acting, the developer is circulated in the direction F ₄ indicated by the arrow in FIG. 2, that is, from the stirring auger 5 side to the supply auger 4 side through the communication port 23b.

(Support part)
FIG. 3 is a cross-sectional view showing a detailed configuration of the support portion. The support portion 6 is supported by a bearing 60 so that the shaft end portion 45A of the first rotation shaft 40A and the shaft end portion 45B of the second rotation shaft 40B can rotate independently. As the bearing 60, for example, a ball bearing or the like can be used. The outer ring of the ball bearing is fixed between the sub housing 2B and the partition wall 23, and the inner ring of the ball bearing is fixed to the shaft end portions 45A and 45B by a retaining ring 61 such as an E ring.

(Developer operation)
4A to 4C are main part cross-sectional views showing the developer replenishment operation according to the present embodiment, and FIG. 4D is a main part cross-sectional view showing the developer replenishment operation in the comparative example. It is. The cross-sectional position in FIG. 4 is the AA line in FIG. 2, but illustration of the conveying blades 41 and 52 is omitted. Further, in the figure, the white arrow indicates the movement of the developer, and the normal arrow that is not white indicates the rotation direction of the blade. The operation of the developing device 1 will be described below with reference to FIG.

Conveying blade 41 of the feed auger 4, by the rotation of the first rotation shaft 40A, and supplies the developer to the developing roller 3 while conveying the developer in the axial direction F ₁ indicated by the arrow in FIG. The developing roller 3 supplies a developer to the photosensitive drum 100 to develop the electrostatic latent image on the photosensitive drum 100. Circulation vanes 42 of the feed auger 4, by acting the developer having been conveyed in the axial direction F ₁ as push back by the rotation of the first rotation shaft 40A, stirring augers 5 the developer from the supply auger 4 side 2 and the excess developer whose retained amount of developer on the supply auger 4 side exceeds a certain amount is discharged leftward in FIG. The discharge blade 43 of the supply auger 4 discharges excess developer that has passed over the circulation blade 42 to the discharge port 22.

On the other hand, the conveying blade 52 of the stirring auger 5 conveys the developer circulated from the supply auger 4 side through the communication port 23 a in the axial direction F ₃ by the rotation of the rotating shaft 50. Circulation vane 53 of the stirring auger 5 by acting to push back the developer having been conveyed in the axial direction F ₃ by the transfer blade 52, via the communication port 23b of the developer from the stirring auger 5 side supply Circulate to the auger 4 side.

  When the amount of developer held in the developing device 1 falls below a certain amount, this is detected by a sensor, and the developer is removed from the developer cartridge (not shown) as indicated by the arrow Fa in FIG. Replenished from the supply port 21. The developer supplied from the supply port 21 is sent to the stirring auger 5 side by the action of the supply blades 44 of the supply auger 4 and gravity, as indicated by arrows Fb and Fc in FIG. The replenishment blade 51 of the stirring auger 5 supplies the developer replenished from the replenishment port 21 to the conveyance blade 52.

  When the developer reaches a high temperature (for example, 40 to 60 ° C.) due to changes in the usage environment such as the usage frequency and cooling performance of the developing device 1, the developer is fed into the supply auger 4 and the stirring auger as shown in FIG. 5 and the developer pile 10 may be formed. In the present embodiment, the replenishment blade 44 is rotated counterclockwise in FIGS. 1 and 4, so that the developer sent downward by the replenishment blade 44 as shown in FIG. The peak of the developer 10 is broken from the side surface direction and sent to the stirring auger 5 side.

  On the other hand, as shown in the comparative example of FIG. 4D, when the replenishment blade 44 is rotated clockwise, the crest of the developer 10 accumulated between the supply auger 4 and the stirring auger 5 is not destroyed. In some cases, the peak of the developer 10 gradually increases, and finally, the developer cannot be replenished. However, this embodiment can avoid such a state.

(Modification of supply auger and stirring auger)
5 and 6 show a modification of the supply auger and the stirring auger, FIG. 5A is a cross-sectional view showing a modification of the supply auger and the stirring auger in the rotational direction, and FIG. 5B is a supply auger. It is sectional drawing which shows the modification of the arrangement | positioning relationship of a stirring auger. In addition, the cross-sectional position of FIG. 5 is the AA line of FIG. FIG. 6 is a view showing a modification of the arrangement relationship of the supply auger and the stirring auger with respect to the developing roller.

The modification shown in FIG. 5A is obtained by rotating the stirring auger 5 counterclockwise in FIG. 5A in the present embodiment. In this case, the developer is transported in the directions F ₃ and F ₄ shown in FIG. 2 by setting the replenishment blade 51, the transport blade 52, and the circulation blade 53 of the stirring auger 5 in the opposite directions to those in FIG. 2. be able to.

  In the modification shown in FIG. 5B, the stirring auger 5 is arranged in the horizontal direction with respect to the supply auger 4. Even in such a configuration, when the developer rises to a high temperature and the fluidity decreases, the developer accumulates on the developer path from the supply blade 44 of the supply auger 4 to the supply blade 51 of the stirring auger 5. There is a case. By rotating the supply blade 44 of the supply auger 4 counterclockwise in FIG. 5B as in this modification, the pile of accumulated developer can be broken from the side surface direction and sent to the stirring auger 5 side.

  In the modification shown in FIG. 6, the stirring auger 5 is arranged on the same side as the developing roller 3 with respect to the plane F passing through the rotation axis of the supply auger 4 in the direction of gravity. In this case, the conveyance blade 41 and the replenishment blade 44 are rotated to the right, and the stirring auger 5 is rotated to the left. Also in the configuration shown in the figure, the same operations and effects as described in FIG.

(Modification of support part)
7A to 7C are cross-sectional views showing modifications of the support portion. In addition, a support part is not restricted to above-mentioned FIG.3 and FIG.7 (a)-(c).

  The support portion 6 of the modified example shown in FIG. 7A has a sliding bearing 62 so that the shaft end portion 45A of the first rotating shaft 40A and the shaft end portion 45B of the second rotating shaft 40B can rotate independently. Is supported by the sub-housing 2B. The sliding bearing 62 includes a sintered bearing having a bearing layer 62b in which a solid lubricant is dispersed in a sintered layer on the inner surface of the back metal 62a, and a resin bearing having a bearing layer 62b mainly composed of a resin on the inner surface of the back metal 62a. Etc. can be used. The back metal 62 a of the slide bearing 62 is fixed between the sub housing 2 </ b> B and the partition wall 23.

  The support portion 6 of the modified example shown in FIG. 7B is configured such that the shaft end portion 45A of the first rotation shaft 40A is rotatably fitted in the hole 46 formed in the second rotation shaft 40B. The modification shown in the figure is not a structure in which the first and second rotating shafts 40A and 40B are supported from the sub housing 2B and the partition wall 23 as shown in FIG. 7A, but the first and second rotating shafts. The structure is supported by 40A and 40B.

  The support portion 6 of the modified example shown in FIG. 7C is formed with a large-diameter hole and a small-diameter hole 46 in the first and second rotating shafts 40A and 40B, and the large-diameter hole shown in FIG. The first and second rotating shafts 40A and 40B are rotatably connected by disposing the sliding bearing 65 as described above, and disposing the pin 64 in the opening of the sliding bearing 65 and the small-diameter hole 46. The modification shown in the figure is a structure that is supported by the first and second rotating shafts 40A and 40B as in FIG. 7B.

[Other embodiments]
In addition, this invention is not limited to the said embodiment, A various deformation | transformation is possible within the range which does not change the summary. For example, in the above embodiment, the supply blades 44 and the discharge blades 43 are divided and supported independently to rotate, but the discharge blades 43 and the conveyance blades 41 It is good also as a structure which divides | segments in between or other places, and supports each so that it can rotate independently.

  The present invention is applicable to a developing device of an image forming apparatus such as an electrophotographic copying machine, a facsimile machine, and a printer.

FIG. 1 is a cross-sectional view taken along the line AA of FIG. 2, showing the main configuration of the developing device according to the embodiment of the present invention. FIG. 2 is a cross-sectional view of the main structure of the developing device according to the embodiment of the present invention as viewed from above. FIG. 3 is a cross-sectional view showing a detailed configuration of the support portion. 4A to 4C are main part cross-sectional views showing the developer replenishment operation according to the present embodiment, and FIG. 4D is a main part cross-sectional view showing the developer replenishment operation of the reference example. It is. FIG. 5 shows a modification of the supply auger and the stirring auger, FIG. 5 (a) shows a modification of the rotation direction of the supply auger and the stirring auger, and FIG. 5 (b) shows a modification of the supply auger and the stirring auger. It is a figure which shows the modification of arrangement | positioning relationship. FIG. 6 is a view showing a modification of the arrangement relationship of the supply auger and the stirring auger with respect to the developing roller. 7A to 7C are cross-sectional views showing modifications of the support portion.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Developing device, 2 ... Housing, 2A ... Main housing, 2B ... Sub housing, 3 ... Developing roller, 4 ... Supply auger, 5 ... Agitation auger, 6 ... Supporting part, 7 ... Bearing, 8A-8C ... Gear, 8D , 8E ... idler gear, 9A ... main motor, 9B ... sub motor, 10 ... developer, 20 ... development opening, 21 ... supply port, 22 ... discharge port, 23 ... partition wall, 23a, 23b, 23c ... communication port, 40A ... first rotating shaft, 40B ... second rotating shaft, 41 ... conveying blade, 42 ... circulating blade, 43 ... discharge blade, 44 ... supply blade, 44a ... small blade, 45A, 45B ... shaft end 46, hole, 50, rotating shaft, 51 ... supply blade, 52 ... conveying blade, 53 ... circulating blade, 60 ... bearing, 61 ... retaining ring, 62 ... sliding bearing, 62a ... back metal, 62b ... Bear Ing layer, 64 ... pin 65 ... sliding bearings, 100 ... photosensitive drum

Claims (4)

A developer holder for holding the developer;
The first and second rotating shafts arranged on the coaxial line and rotatably provided independently from each other, and formed on the first rotating shaft, the developer is developed along a predetermined axial direction. A first conveying blade that can be supplied to the agent holder, and a first replenishing blade that is formed on the second rotation shaft and conveys the developer replenished from the outside of the apparatus. A conveying member;
A second transport member having a second transport blade for transporting the developer transported by the first supply blade toward the first transport blade;
The first rotation shaft is driven to rotate so that the first conveying blade moves in the order of the gravity direction downward, the side on which the developer holder is disposed, and the direction of gravity upward, and the second rotation. A developing device comprising: a drive unit that rotationally drives the shaft so that the first replenishing blade moves in the gravity direction lower side, the side on which the second transport member is disposed, and the gravity direction upper side.   The developing device according to claim 1, wherein the driving unit rotationally drives the second transport member in the same direction as a rotation direction of the first rotation shaft.   2. The developing device according to claim 1, wherein the first transport blade and the first supply blade have different developer transport directions at a boundary between the first rotation shaft and the second rotation shaft.   An image forming apparatus comprising the developing device according to claim 1.

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