JP2015152856A - Powder conveying member, powder conveying device, developing device, process unit, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a powder conveying member that can contribute to size reduction and efficiently convey powder in two directions.SOLUTION: There is provided a powder conveying member conveying powder used for image formation, the powder conveying member including a rotation shaft 77a, and having a first conveying part B having a plurality of conveying surfaces b1 inclined with respect to the rotation shaft 77a and arranged side by side over the shaft direction, and a second conveying part C having a conveying surface c1 parallel to the rotation shaft 77a and arranged continuously over the shaft direction, which are provided in the same shaft direction area and different rotation direction area from each other.

Description

  The present invention relates to a powder conveying member that conveys powder used for image formation, a powder conveying device including the powder conveying member, a developing device, a process unit, and an image forming apparatus.

  2. Description of the Related Art Image forming apparatuses such as copiers, printers, facsimiles, and multi-function machines thereof are provided with a powder conveying member that conveys powder such as toner used for image formation. Examples of the powder conveying member include a conveying screw provided with spiral blades on the outer peripheral surface of the rotating shaft (see Patent Document 1), and a conveying paddle provided with blades parallel to the rotating shaft (see Patent Document 2). ) Etc. are known.

  A conveyance screw mainly provides conveyance force to an axial direction by rotating. On the other hand, the conveyance paddle applies a conveyance force mainly in the rotation direction by rotating. Since these powder conveying members basically generate a conveying force in one of the axial direction and the rotational direction, they are generally used properly according to the conveying direction. Therefore, when it is desired to effectively transport the powder in the axial direction and the rotational direction, it is necessary to provide both a transport screw and a transport paddle. However, when both the conveying members are provided, there is a problem that it is disadvantageous for downsizing of the apparatus.

  Therefore, in view of such circumstances, the present invention can contribute to downsizing and a powder transport member capable of effectively transporting powder in two directions, and a powder transport device including the powder transport member A developing device, a process unit, and an image forming apparatus are provided.

  In order to solve the above-described problems, the present invention provides a powder conveying member that conveys powder used for image formation, and has a rotating shaft, and a plurality of conveying surfaces inclined with respect to the rotating shaft are arranged in the axial direction. In the same axial direction region, the first transport unit disposed so as to be adjacent to each other and the second transport unit in which the transport surface parallel to the rotation axis is continuously disposed in the axial direction, It is characterized by being provided in mutually different rotational direction regions.

  According to the powder transport member of the present invention, by rotating, the powder can be transported in the axial direction by the first transport unit, and the powder is transported in the rotational direction by the second transport unit. It is possible. Thus, the powder can be effectively conveyed in two directions by one powder conveying member, which can contribute to downsizing.

1 is a schematic configuration diagram of an image forming apparatus according to an embodiment of the present invention. It is sectional drawing of the process unit mounted in the said image forming apparatus. It is a figure which shows the structure of the pumping-up member. It is a figure which shows the modification of a scooping member. FIG. 3 is a diagram illustrating a configuration of a toner detection unit. FIG. 6 is a diagram illustrating a state where toner is pumped up by a pumping member. FIG. 6 is a cross-sectional view illustrating a toner circulation path in the developing device. FIG. 6 is a cross-sectional view illustrating a toner circulation path in the developing device. It is a figure which shows the example which made the 1st partition member contact the drawing-up member with respect to the trailing direction. It is a figure which shows the structure of the pumping member which concerns on other embodiment of this invention. It is a figure which shows the structure of the pumping member which concerns on other embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In each of the drawings for explaining the embodiments of the present invention, constituent elements such as members and components having the same function or shape are described once by giving the same reference numerals as much as possible. Then, the explanation is omitted.

  First, an overall configuration of an image forming apparatus according to an embodiment of the present invention will be described with reference to FIG. An image forming apparatus 1 shown in FIG. 1 is a color laser printer, and an intermediate transfer belt 30 is provided at a substantially central portion in the height direction of the apparatus main body. Below the intermediate transfer belt 30, four process units 4Y, 4M, 4C, and 4K are provided. Each process unit 4Y, 4M, 4C, 4K contains developers of different colors of yellow (Y), magenta (M), cyan (C), and black (K) corresponding to the color separation components of the color image. The configuration is the same except that. In the present embodiment, a case where a one-component developer composed only of toner is used as a developer (powder) used for image formation is shown, but a two-component developer composed of toner and carrier can also be used. . The toner may be either a pulverized toner or a polymerized toner. The external additive material for the toner may contain silicon oil-containing silica. For the external addition of silica containing silicon oil, for example, 2 parts by weight of hydrophobic silica RY50 (manufactured by Nippon Aerosil Co., Ltd.) is added to 100 parts by weight of pulverized toner or polymerized toner, and the peripheral speed is 40 m / S with a 20 L Henschel mixer. Mixing was performed for a minute. Thereafter, it is obtained by sieving with a sieve having an opening of 75 μm.

  Each of the process units 4Y, 4M, 4C, and 4K includes a drum-shaped photosensitive member 5 as a latent image carrier, a charging device 6 that charges the surface of the photosensitive member 5, and a development that supplies toner to the surface of the photosensitive member 5. An apparatus 7, a cleaning device 8 that cleans the surface of the photoconductor 5, an exposure device 9 that exposes the surface of the photoconductor 5, and the like are provided. In the present embodiment, an LED unit is used as the exposure device 9.

  A transfer device 3 is disposed above each process unit 4Y, 4M, 4C, 4K. The transfer device 3 includes an intermediate transfer belt 30 as an intermediate transfer member, four primary transfer rollers 31 as primary transfer means, a secondary transfer roller 36 as secondary transfer means, a secondary transfer backup roller 32, A belt cleaning device 35.

  The intermediate transfer belt 30 is an endless belt, and is stretched between a secondary transfer backup roller 32 and a roller 33. Here, when the secondary transfer backup roller 32 is driven to rotate, the intermediate transfer belt 30 runs (rotates) in the direction indicated by the arrow in the figure.

  Each of the four primary transfer rollers 31 sandwiches the intermediate transfer belt 30 with each photoconductor 5 to form a primary transfer nip. Further, a power source (not shown) is connected to each primary transfer roller 31 so that a predetermined DC voltage (DC) and / or AC voltage (AC) is applied to each primary transfer roller 31.

  The secondary transfer roller 36 sandwiches the intermediate transfer belt 30 with the secondary transfer backup roller 32 to form a secondary transfer nip. Similarly to the primary transfer roller 31, a power source (not shown) is also connected to the secondary transfer roller 36, and a predetermined DC voltage (DC) and / or AC voltage (AC) is applied to the secondary transfer roller 36. It has come to be.

  The belt cleaning device 35 includes a cleaning brush and a cleaning blade disposed so as to contact the intermediate transfer belt 30. A waste toner transfer hose (not shown) extending from the belt cleaning device 35 is connected to a waste toner container (not shown).

  Four toner cartridges 2Y, 2M, 2C, and 2K that store new toner for replenishment are detachably mounted on the upper portion of the printer body. A replenishment path (not shown) is provided between the toner cartridges 2Y, 2M, 2C, and 2K and the developing devices 7, and each development from the toner cartridges 2Y, 2M, 2C, and 2K is performed via the replenishment path. New toner is supplied to the apparatus 7.

  A lower part of the printer main body is provided with a paper feed tray 10 that stores paper as a recording medium, a paper feed roller 11 that carries out the paper from the paper feed tray 10, and the like. In addition to plain paper, the recording medium includes cardboard, postcard, envelope, thin paper, coated paper (coated paper, art paper, etc.), tracing paper, OHP sheet, and the like. Although not shown, a manual paper feed mechanism may be provided.

  In the printer main body, a transport path R is provided for discharging paper (not shown) from the paper feed tray 10 through the secondary transfer nip to the outside of the apparatus. In the transport path R, a pair of registration rollers 12 serving as timing rollers for transporting the paper to the secondary transfer nip at the transport timing is disposed upstream of the position of the secondary transfer roller 36 in the paper transport direction. Yes.

  Further, a fixing device 20 for fixing an unfixed image transferred to the paper is disposed downstream of the position of the secondary transfer roller 36 in the paper transport direction. Further, a pair of paper discharge rollers 13 for discharging the paper to the outside of the apparatus is provided downstream of the fixing device 20 in the paper conveyance direction of the conveyance path R. A discharge tray 14 for stocking sheets discharged outside the apparatus is provided on the upper surface of the printer main body.

  Next, the basic operation of the printer will be described with reference to FIG.

  When the image forming operation is started, each photoconductor 5 in each process unit 4Y, 4M, 4C, 4K is rotationally driven clockwise by a driving device (not shown), and the surface of each photoconductor 5 is charged by the charging device 6. It is uniformly charged to a predetermined polarity. The surface of each charged photoconductor 5 is irradiated with laser light from the exposure device 9 to form an electrostatic latent image on the surface of each photoconductor 5. At this time, the image information to be exposed on each photoconductor 5 is single-color image information obtained by separating a desired full-color image into color information of yellow, magenta, cyan, and black. In this way, toner is supplied to each electrostatic latent image formed on each photoconductor 5 by each developing device 7, whereby the electrostatic latent image is visualized (visualized) as a toner image. .

  When the image forming operation is started, the secondary transfer backup roller 32 is driven to rotate counterclockwise in the figure, and the intermediate transfer belt 30 is caused to run in the direction indicated by the arrow in the figure. Further, by applying a constant voltage having a polarity opposite to the toner charging polarity or a voltage controlled by a constant current to each primary transfer roller 31, the primary transfer nip between each primary transfer roller 31 and each photoreceptor 5 is applied. A transfer electric field is formed.

  Thereafter, when each color toner image on the photoconductor 5 reaches the primary transfer nip as each photoconductor 5 rotates, the toner image on each photoconductor 5 is generated by the transfer electric field formed in the primary transfer nip. Are sequentially superimposed and transferred onto the intermediate transfer belt 30. Thus, a full color toner image is carried on the surface of the intermediate transfer belt 30. Further, the toner on each photoconductor 5 that could not be transferred to the intermediate transfer belt 30 is removed by the cleaning device 8. Then, the surface of each photoconductor 5 is neutralized by a neutralizing device (not shown), and the surface potential is initialized.

  In the lower part of the printer, the paper feed roller 11 starts to rotate, and the paper is sent out from the paper feed tray 10 to the transport path R. The sheet sent to the conveyance path R is temporarily stopped by the registration roller 12.

  Thereafter, rotation of the registration roller 12 is started at a predetermined timing, and the sheet is conveyed to the secondary transfer nip in accordance with the timing when the toner image on the intermediate transfer belt 30 reaches the secondary transfer nip. At this time, a transfer voltage having a polarity opposite to the toner charging polarity of the toner image on the intermediate transfer belt 30 is applied to the secondary transfer roller 36, thereby forming a transfer electric field in the secondary transfer nip. . Then, the toner image on the intermediate transfer belt 30 is collectively transferred onto the sheet by the transfer electric field. At this time, the residual toner on the intermediate transfer belt 30 that could not be transferred onto the paper is removed by the belt cleaning device 35, and the removed toner is conveyed to a waste toner container (not shown) and collected.

  Thereafter, the sheet is conveyed to the fixing device 20, and the fixing device 20 fixes the toner image on the sheet to the sheet. Then, the paper is discharged out of the apparatus by the paper discharge roller 13 and stocked on the paper discharge tray 14.

  The above description is an image forming operation when a full-color image is formed on a sheet. A single-color image is formed using any one of the four process units 4Y, 4M, 4C, and 4K. Two or three process units can be used to form a two or three color image.

  In the present embodiment, process units 4Y, 4M, 4C, and 4K are disposed below the intermediate transfer belt 30 that rotates in the direction of the arrow in FIG. In this case, the primary transfer nip (nip between the photosensitive member 5 and the primary transfer roller 31) and the secondary transfer nip (the secondary transfer roller 36 and the secondary transfer roller) are compared with the case where the process unit is disposed above the intermediate transfer belt 30. The distance from the transfer backup roller 32 to the nip is shortened. Thus, the travel distance of the intermediate transfer belt 30 is shortened from the completion of the primary transfer until the secondary transfer is performed, and the time required for the first print (first print time) can be shortened. Further, while the intermediate transfer belt 30 is rotating, the photosensitive member 5 continues to rotate in synchronization with the rotation, and toner is continuously supplied from the photosensitive member 5 to the intermediate transfer belt 30. For this reason, by shortening the travel distance of the intermediate transfer belt 30 as described above, it is possible to suppress the wear amount of the photosensitive member and the toner consumption amount.

  Further, since the belt cleaning device 35 is provided immediately after the secondary transfer nip, it is disposed above the intermediate transfer belt 30 as shown in the figure. If the process units 4Y, 4M, 4C, and 4K are arranged above the intermediate transfer belt 30, the process units 4Y, 4M, 4C, and 4K and the belt cleaning device 35 are arranged side by side in the horizontal direction, and the horizontal direction of the image forming apparatus. The direction width increases. On the other hand, as shown in FIG. 1, the process units 4Y, 4M, 4C, 4K and the belt cleaning device 35 are horizontally arranged by disposing the process units 4Y, 4M, 4C, 4K below the intermediate transfer belt 30. There is no need to arrange them side by side in the direction, and the horizontal width of the image forming apparatus can be suppressed.

  FIG. 2 is a cross-sectional view of the process unit 4 (the alphabets Y, M, C, and K indicating each color are omitted) of the present embodiment. As described above, the process unit 4 includes the photoconductor 5, the charging device 6, the developing device 7, the cleaning device 8, and the exposure device 9. The charging device 6 includes a charging roller 61 as a charging member that contacts and charges the photoreceptor 5. The cleaning device 8 includes a cleaning member 81 that removes the developer (toner) attached to the surface of the photoreceptor 5 and a waste toner transport member 82 that transports the waste toner removed by the cleaning member 81.

  The developing device 7 includes a housing 70 that serves as a housing that accommodates toner, a developing roller 71 that serves as a developer carrier that carries toner, and a supply roller 72 that serves as a developer supply member that supplies toner to the developing roller 71. , A regulating blade 73 as a developer regulating member that regulates the layer thickness of the toner carried on the developing roller 71, and conveyance as a first developer conveying member (first powder conveying member) that conveys toner. A screw 76 and a pumping member 77 as a second developer conveying member (second powder conveying member) are provided. The developer carrying member is not limited to the developing roller 71, and may be, for example, a developing belt. Further, the developer regulating member is not limited to the regulating blade 73 but may be a regulating roller, for example.

  In addition, a first partition member 74 and a holding member 75 that holds the first partition member 74 are provided in the housing 70. By the first partition member 74 and the holding member 75, a mixing chamber S1 that is a first developer accommodating chamber in which the conveying screw 76 and the pumping member 77 are accommodated, and a second developer in which the supply roller 72 is accommodated. A supply room S2 which is a storage room is partitioned. In the illustrated example, a mixing chamber S1 is provided below the supply chamber S2, and the supply chamber S2 and the mixing chamber S1 communicate with each other via an upper communication path Q1 and a lower communication path Q2.

  In addition, the mixing chamber S1 includes an upper first mixing chamber U1 in which the conveying screw 76 is accommodated and a lower side in which the pumping member 77 is accommodated by a second partition member 78 provided integrally with the housing 70. And a second mixing chamber U2. The second partition member 78 extends in the longitudinal direction of the conveying screw 76 and the pumping member 77 (direction orthogonal to the paper surface of FIG. 2), and the first mixing chamber U1 and the first mixing chamber U1 are arranged at both ends in the longitudinal direction. A communication path that communicates with the two mixing chambers U2 is formed.

  The first partition member 74 is made of an elastic member such as a thin plate that is flexible and elastically deformable, and is made of, for example, metal or resin. The first partition member 74 is provided in parallel with the axial direction of the developing roller 71 and the supply roller 72, and has the same axial dimension as the developing roller 71 and the supply roller 72. The first partition member 74 has an upper end fixed to a holding member 75 provided in the vicinity of the supply roller 72 (just below the supply roller 72 in the illustrated example), and extends downward from the fixed portion. Further, the lower end portion of the first partition member 74 is in contact with the pumping member 77 from above over the entire region in the axial direction.

  The conveying screw 76 includes a rotation shaft 76a parallel to the rotation shafts of the developing roller 71 and the supply roller 72, and a spiral blade 76b provided on the outer peripheral surface of the rotation shaft 76a. The conveyance screw 76 conveys toner mainly in the axial direction by rotating. In the present embodiment, the conveying screw 76 is disposed at a position regulated by the regulating blade 73, that is, vertically below a contact position between the developer carried on the developing roller 71 and the regulating blade 73.

  The scooping member 77 includes a rotation shaft 77a parallel to the rotation shafts of the developing roller 71 and the supply roller 72, a first conveyance unit B that conveys toner mainly in the axial direction, and conveys toner mainly in the rotation direction. And a second transport unit C.

FIG. 3 shows a specific configuration of the pumping member 77.
3, (a) is a drawing of the pumping member viewed from the axial direction, (b) is a perspective view of the pumping member, (c) is a drawing of the pumping member viewed from the direction of the arrow X1 shown in (a), (d ) Is a view of the pumping member viewed from the direction of the arrow Y1 shown in (a), and (e) is a view of the pumping member viewed from the direction of the arrow Z1 shown in (a).

  As shown in FIG. 3, a plurality of blades 77b having a conveying surface b1 inclined with respect to the rotating shaft 77a are arranged in the first conveying portion B of the pumping member 77 so as to be adjacent in the axial direction. Yes. In other words, the 1st conveyance part B is a shape which deleted the blade | wing provided spirally in the outer peripheral surface of the rotating shaft by the half circumference of a rotation direction.

  On the other hand, the 2nd conveyance part C is comprised by the square rod-shaped member 77c extended in the axial direction of the rotating shaft 77a. In the example shown in FIG. 3, the second transport unit C is configured by a triangular prismatic rod-shaped member 77c. However, the rectangular rod-shaped member 77c may be a rectangular prism or other polygonal shape as in the example illustrated in FIG. A column or an elliptical column may be formed. Thus, the 2nd conveyance part C comprised by the square rod-shaped member 77c has the conveyance surface c1 parallel to the rotating shaft 77a on the surface continuously over an axial direction. In the example shown in FIG. 3, two conveying surfaces c1 having different directions are provided on the surface of the rectangular bar-shaped member 77c.

  Moreover, the 1st conveyance part B and the 2nd conveyance part C are provided in the rotation direction area | region which mutually differs in the same axial direction area | region. In the present embodiment, the area where the first conveyance unit B and the second conveyance unit C are provided is set to be a half circumference in the rotation direction of the rotation shaft 77a, but the size of the area where both conveyance units B and C are provided. You may change suitably.

The mixing chamber S1 is provided with a toner detection unit as a developer detection unit that detects the amount of toner contained in the mixing chamber S1.
As shown in FIG. 5, the toner detection unit 90 includes a first light guide member 91 and a second light guide member 92 fixed to the housing 70, and a cleaning member 93 fixed to the conveying screw 76. One end of the first light guide member 91 is disposed to face a light emitting element (not shown), and the other end functions as a light emitting surface 91a. One end of the second light guide member 92 is disposed to face the light receiving element (not shown), and the other end functions as a light receiving surface 92a. The light emitting surface 91a of the first light guide member 91 is opposed to the light receiving surface 92a of the second light guide member 92, and is opposed in the axial direction in the illustrated example.

  The cleaning member 93 is formed of a flexible plate-like member, for example, a PET sheet. The cleaning member 93 rotates together with the conveying screw 76. When the cleaning member 93 rotates and the light emitting surface 91a of the first light guide member 91 and the light receiving surface 92a of the second light guide member 92 and the cleaning member 93 slide, the light emitting surface 91a and the light receiving surface 92a are moved. Adhering toner is removed. Further, as the cleaning member 93 rotates, the toner accumulated in the lower portion of the mixing chamber S1 is scraped up by the cleaning member 93, and the scraped toner passes between the light emitting surface 91a and the light receiving surface 92a. At this time, when the toner scraped up by the cleaning member 93 passes between the light emitting surface 91a and the light receiving surface 92a, the light emitted from the light emitting surface 91a does not reach the light receiving surface 92a, and the light receiving element outputs a signal. Not detected. In other cases, the light emitted from the light emitting surface 91a reaches the light receiving surface 92a, and the light receiving element detects the signal. At this time, the amount of toner picked up by the cleaning member 93 varies depending on the amount of toner in the mixing chamber S1, and thus the light reception time by the light receiving element varies. Therefore, the amount of toner in the mixing chamber S1 can be detected by detecting the light receiving time by the light receiving element.

  The toner detection unit 90 may be disposed in the second mixing chamber U2 in which the pumping member 77 is accommodated, and the cleaning member 93 may be provided in the pumping member 77.

Hereinafter, the toner conveying operation in the developing device will be described.
First, the operation of pumping up toner by the pump-up member 77 will be described with reference to FIG.
When the pumping member 77 is rotated in the direction of arrow A by a driving means (not shown), the transport surface c1 of the second transport unit C formed in a square bar shape, the inner surface of the housing 70, and the first partition member 74 cooperate. Then, the toner T in the second mixing chamber U2 is pumped upward, and the toner is pushed into the supply chamber S2 via the communication path Q2 (see FIGS. 6A to 6D). By repeating this, the toner T in the second mixing chamber U2 is sequentially supplied to the supply chamber S2. The pumping member 77 may be always rotated or may be rotated only when a command is given.

  While the pumping member 77 is rotating, the first partition member 74 is in a state in which the lower end is elastically pressed against the pumping member 77 while being slightly curved. Thereby, even when the pumping member 77 rotates, the first partition member 74 always contacts the pumping member 77. Therefore, it is possible to prevent the toner T pumped by the pumping member 77 from returning to the second mixing chamber U2 from the gap between the first partition member 74 and the pumping member 77. Further, if the pumping member 77 is always rotated, the toner is always pushed in from the lowermost part of the second mixing chamber U2, so that the backflow of the toner into the second mixing chamber U2 can be more reliably regulated.

Next, a toner circulation operation performed by the conveying screw 76 and the pumping member 77 will be described with reference to FIG.
As shown in FIG. 7, the first mixing chamber U1 and the second mixing chamber U2 communicate with each other via communication paths J1 and J2 provided at both ends in the longitudinal direction of the second partition member 78. Yes. In the present embodiment, the conveying screw 76 is longer than the pumping member 77 in the axial direction. In addition, the first mixing chamber U <b> 1 that accommodates the conveying screw 76 is also formed longer than the second mixing chamber U <b> 2 that accommodates the pumping member 77. The housing 70 includes a main body 70a that houses the pumping member 77, the developing roller 71, and the like, and a protrusion that protrudes in the axial direction from the main body 70a and covers one end side (the right end side in FIG. 7) of the conveying screw 76. 70b.

  A new toner supply port 79 for supplying new toner from the toner cartridge 2 (the alphabets Y, M, C, and K indicating the respective colors are omitted) is provided above the protruding portion 70b. The new toner supply port 79 is provided with opening / closing means such as a shutter (not shown). Normally, the new toner supply port 79 is closed, but when the toner amount detected by the toner detection unit 90 falls below the reference value, the opening / closing means is opened, whereby the first toner supply port 79 is opened via the new toner supply port 79. New toner is replenished to one mixing chamber U1. The new toner supply port 79 may be provided in the second mixing chamber U2. In this case, the protruding portion 70b is not provided in the housing, and the conveying screw 76 and the pumping member 77 have the same axial dimensions as the developing roller 71 and the like, and are accommodated in the main body portion 70a.

  When the conveyance screw 76 is rotated, the toner is conveyed in the direction of arrow F in FIG. On the other hand, when the pumping member 77 rotates, the toner is transported in the direction of arrow G in FIG. 7 by the blades 77b provided in the first transport unit B. That is, the conveying screw 76 and the pumping member 77 convey toner in opposite directions. Further, the toner conveyed by the conveying screw 76 and the pumping member 77 is pressed against the inner surface of the housing 70 on the downstream side in the conveying direction, respectively, and the second mixing chamber U1 and the second mixing chamber J1 are connected to the second through the communication paths J1 and J2. It is conveyed to the mixing chamber U2 and from the second mixing chamber U2 to the first mixing chamber U1. Thus, the toner is conveyed in the reverse direction by the conveying screw 76 and the pumping member 77, whereby the toner is circulated and conveyed along the circulation path H shown in FIG.

  Further, when new toner is supplied from the toner cartridge 2 to the first mixing chamber U1 through the new toner supply port 79, it is transported along the transport path K shown in FIG. The new toner merges with the non-new toner circulated and conveyed along the circulation path H on the downstream side in the conveyance direction.

Next, the overall flow of the toner conveying operation performed in the developing device 7 will be described.
When the image forming operation is started, as shown in FIG. 8, the photoconductor 5, the developing roller 71, and the supply roller 72 rotate in the arrow direction. At the same time, the conveying screw 76 and the pumping member 77 are rotated. Due to the rotation of the pumping member 77, the toner in the second mixing chamber U2 is pumped into the supply chamber S2 via the communication path Q2 (see FIG. 6), and the toner T accumulates in the supply chamber S2. When the upper surface of the toner T reaches the supply roller 72, the toner is carried on the developing roller 71 via the supply roller 72. At this time, since no supply member such as a screw is provided in the supply chamber S <b> 2, the upper surface of the toner is substantially horizontal in the axial direction, and the toner can be uniformly supplied to the entire axial direction of the developing roller 71. In addition, since the surface of the first partition member 74 that forms the inner wall of the supply chamber S2 and the inner surface of the housing 70 that faces the first partition member 74 are formed as smooth surfaces without unevenness, toner stays on the inner wall of the supply chamber S2. Can be prevented.

  Of the toner carried on the developing roller 71, excess toner is regulated by the regulating blade 73 and accommodated in the first mixing chamber U1. The non-new toner regulated by the regulation blade 73 freely falls on the conveying screw 76 arranged below the regulation position. When the opening / closing means of the new toner supply port 79 is opened, new toner is supplied from the toner cartridge 2 onto the conveying screw 76. Then, the non-new toner and the new toner are agitated and mixed by circulating the toner inside the mixing chamber S1 by the conveying screw 76 and the pumping member 77. Thus, the homogeneous toner sufficiently stirred in the mixing chamber is supplied again to the supply chamber S2 by the pumping member 77.

  As described above, inside the developing device 7, the toner is regulated by the regulation blade 73 and is freely dropped into the first mixing chamber U <b> 1 and collected. Thereby, as shown in FIG. 8, the first mixing chamber U1 → the second mixing chamber U2 → the communication path Q2 → the supply chamber S2 → the supply roller 72 → the developing roller 71 → the communication path Q1 → the first mixing chamber U1. Thus, a toner circulation path M (first circulation path) is formed. Thus, by circulating the toner inside the developing device, local deterioration of the toner can be prevented, and problems such as image fading due to the deteriorated toner can be prevented. In particular, a one-component developer is likely to cause toner deterioration typified by fluidity deterioration and insufficient charging due to toner external additive peeling or toner cracking. However, by circulating toner as described above, Deterioration can be prevented.

  Further, in the mixing chamber S1, the toner is transported along the circulation path H (second circulation path) by the transport screw 76 and the pumping member 77 having different transport directions (see FIG. 7). The toner can be sufficiently stirred and mixed. In particular, by supplying new toner from the new toner supply port 79 in the middle of the circulation path F, the non-new toner and the new toner can be sufficiently stirred and mixed. By supplying the sufficiently mixed homogeneous toner to the supply chamber S2 in this way, a situation in which the non-new toner is supplied again to the developing roller 71 while being unevenly distributed is avoided. Problems such as fading can be prevented.

  In addition, the pumping member 77 includes a first transporting section B that transports toner in the axial direction and a second transporting section C that transports toner in the rotation direction, thereby providing one transporting member (pumping member 77). Thus, the toner can be transported in both the transport direction for mixing the toner in the mixing chamber S1 and the transport direction for pumping the toner into the supply chamber S2. For this reason, it is not necessary to provide two transport members having different transport directions, which can contribute to downsizing and can effectively transport the toner in the direction along the two circulation paths H and M.

  By the way, if there is a gap between the first partition member 74 and the pumping member 77, the toner pumped by the pumping member 77 is not supplied to the supply chamber S2, and the pumping member 77 and the first partitioning member 74 Returning to the second mixing chamber U2 through the gap between the two, there is a possibility that the toner supply efficiency may be reduced. Therefore, as described above, the first partition member 74 is always brought into contact with the pumping member 77 while being elastically deformed, thereby generating a gap between the first partition member 74 and the pumping member 77. Therefore, it becomes possible to supply toner more effectively. Moreover, as the pumping member 77 rotates, a slight vibration is generated in the pumping member 77 due to the abutment of the first partition member 74 that is elastically restored. Therefore, the first transport unit B and the second transport unit are caused by the microvibration. The toner conveyed by C is loosened and the effect of suppressing aggregation is also obtained.

  It is preferable that the toner conveying force to the supply chamber S2 by the pumping member 77 is equal to or greater than the toner conveying force to the second mixing chamber U2 by the conveying screw 76. The toner conveying force of the conveying screw 76 and the pumping member 77 can be adjusted by appropriately changing the dimensional shape, rotation speed, etc. of the conveying screw 76 or the pumping member 77. By setting the relationship of the toner conveying force as described above, the toner can be always present in the vicinity of the supply roller 72 and the developing roller 71, and image quality deterioration due to insufficient toner supply can be prevented. Further, the toner conveying force to the first mixing chamber U1 by the pumping member 77 is made larger than the toner conveying force of the conveying screw 76 to the second mixing chamber U2, so that the lower portion of the second mixing chamber U2 is lowered. It is possible to stir the accumulated toner efficiently.

  Further, as described above, the conveyance screw 76 is arranged vertically below the restriction position by the restriction blade 73, so that the non-new toner separated from the developing roller 71 at the restriction position can be transferred onto the rotating conveyance screw 76. Can be dropped. As a result, the toner dropped from the developing roller 71 is immediately stirred by the conveying screw 76, and mixing with the toner already in the first mixing chamber U1 is started. Further, the new toner is supplied from the new toner supply port 79 to the conveying path by the conveying screw 76, whereby the stirring and mixing of the non-new toner and the new toner is started. Thus, by starting the stirring and mixing of the toner immediately after the restriction position by the restriction blade 73, it is possible to take a longer path from the start of the stirring and mixing until reaching the developing roller 71. It is possible to make it homogeneous.

  Moreover, in the said embodiment, the contact direction of the 1st partition member 74 with respect to the scooping member 77 is the counter direction (The structure which the front-end | tip part of the 1st partition member 74 faces the opposite direction with respect to the rotation direction of the scooping member 77). However, as in the example shown in FIG. 9, the trailing direction (the configuration in which the tip of the first partition member 74 faces the same direction as the rotation direction of the pumping member 77) may be used. Thus, by setting the contact direction of the first partition member 74 to the trailing direction, it is difficult for the first partition member 74 to sag due to the rotation of the pumping member 77.

  The present invention is not limited to the above embodiment. Hereinafter, although other embodiment of this invention is described, the same code | symbol is attached | subjected to the location which has the same function as said embodiment, and duplication description is abbreviate | omitted.

The embodiment shown in FIG. 10 is different from the above embodiment in the configuration of the pumping member 77. A specific configuration of the pumping member 77 will be described with reference to FIG.
11, (a) is a drawing of the pumping member viewed from the axial direction, (b) is a perspective view of the pumping member, (c) is a drawing of the pumping member viewed from the direction of the arrow X2 shown in (a), (d) ) Is a view of the pumping member viewed from the direction of the arrow Y2 shown in (a), and (e) is a view of the pumping member viewed from the direction of the arrow Z2 shown in (a).

  As shown in FIG. 11, in this embodiment, the 2nd conveyance part C is comprised by the several plate-shaped member 77d which protrudes in the radial direction from the rotating shaft 77a. In the example shown in FIG. 11, a total of three plate-like members 77d are provided around the rotation shaft 77a every 90 °, but the angle and the number of the plate-like members 77d may be appropriately changed. Further, the surface of each plate-like member 77d facing the rotation direction is a conveyance surface d1 that is continuous in the axial direction in parallel with the rotation shaft 77a. On the other hand, the 1st conveyance part B becomes the structure which arranged the several blade | wing 77b over the axial direction similarly to the said embodiment.

  In this case, when the pumping member 77 is rotated, the toner is pushed in the rotation direction by each plate-like member 77d, and the inner surface of the housing 70 and the first partition member 74 cooperate to form the second mixing chamber U2. The toner is conveyed to the supply chamber S2 through the communication path Q2. At the same time, the toner is transported in the axial direction by the blades 77b of the first transport section B.

  As described above, also in the embodiment shown in FIGS. 10 and 11, the conveyance direction for mixing the toner in the mixing chamber S1 and the conveyance for pumping the toner into the supply chamber S2 by one conveyance member (pumping member 77). The toner can be conveyed in both directions. Moreover, in this embodiment, the amount of toner retained by the second transport unit C is increased by configuring the second transport unit C with the plate-shaped member 77d. As a result, the amount of toner scraped off by the first partition member 74 increases with the rotation of the pumping member 77, so that the toner pumping ability can be improved.

  The embodiment of the present invention has been described above, but the present invention is not limited to the above-described embodiment, and it is needless to say that various modifications can be made without departing from the gist of the present invention. The image forming apparatus equipped with the developing device according to the present invention is not limited to the printer as shown in FIG. 1, but may be a copier, a facsimile, or a complex machine of these.

  The powder conveying member (pumping member 77) according to the present invention can also be applied to a powder conveying device other than the developing device. For example, the powder conveying member according to the present invention may be provided in a waste toner container that collects waste toner removed by a cleaning device for a photoreceptor or an intermediate transfer belt. As a result, the waste toner can be transported in two directions of the axial direction and the rotational direction by the powder transport member, so that the waste toner can be efficiently stored.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2Y, 2M, 2C, 2K Toner cartridge 3 Transfer apparatus 4Y, 4M, 4C, 4K Process unit 5 Photoconductor (latent image carrier)
6 Charging Device 7 Developing Device 8 Cleaning Device 9 Exposure Device 30 Intermediate Transfer Belt 70 Housing 71 Developing Roller (Developer Carrier)
72 Supply roller (developer supply member)
73 Regulating blade (Developer regulating member)
74 First partition member 76 Conveying screw (first developer conveying member)
77 Pumping member (second developer conveying member)
77a Rotating shaft 77b Blade 77c Square bar member 77d Plate member B First transport portion b1 Transport surface C Second transport portion c1 Transport surface d1 Transport surface S1 Mixing chamber (first developer storage chamber)
S2 supply chamber (second developer storage chamber)
T Toner (Developer)

JP 2010-286552 A JP 2012-159630 A

Claims (10)

A powder conveying member for conveying powder used for image formation,
Having a rotation axis,
A first transport unit disposed so that a plurality of transport surfaces inclined with respect to the rotation axis are adjacent in the axial direction;
A second conveyance unit in which conveyance surfaces parallel to the rotation axis are continuously arranged in the axial direction;
A powder conveying member, wherein the powder conveying member is provided in different rotational direction regions in the same axial direction region.   The powder conveying member according to claim 1, wherein the second conveying unit is configured by a rectangular bar-like member extending in the axial direction of the rotation shaft.   The powder conveying member according to claim 1, wherein the second conveying unit is configured by a plate-like member protruding in a radial direction from the rotation shaft.   The powder conveyance member according to any one of claims 1 to 3, wherein a region in which the first conveyance unit and the second conveyance unit are provided is divided by a half circumference in a rotation direction of the rotation shaft. A powder conveying apparatus comprising a powder conveying member for conveying powder used for image formation, a driving means for driving the powder conveying member, and a casing for accommodating the powder,
5. A powder conveyance device using the powder conveyance member according to claim 1 as the powder conveyance member. A housing for accommodating the developer, a developer carrier for carrying the developer, a developer supply member for supplying the developer to the developer carrier, and an amount of the developer supplied on the developer carrier In a developing device comprising a developer regulating member that regulates the developer and a developer carrying member that carries the developer,
A developing device using the powder conveying member according to any one of claims 1 to 4 as the developer conveying member. The developer carrying member is circulated from the first developer containing chamber by the developer supply member while circulating the developer in the first developer containing chamber containing the developer separated from the developer carrying member. A developing device for transporting a developer to a second developer storage chamber for storing a developer supplied to the body,
The developer is transported in a direction in which the developer is circulated in the first developer storage chamber by the first transport unit, and the developer is transported from the first developer storage chamber by the second transport unit. The developing device according to claim 6, wherein the developing device is configured to be conveyed to a developer storage chamber. A partition member that partitions the first developer accommodating chamber and the second developer accommodating chamber;
The developing device according to claim 7, wherein the partition member is configured by an elastic member that contacts in the axial direction of the developer conveying member and elastically deforms as the developer conveying member rotates. In a process unit comprising at least a latent image carrier that carries a latent image and a developing device that supplies a developer to the latent image on the latent image carrier and develops the latent image,
A process unit comprising the developing device according to claim 6 as the developing device.   An image forming apparatus comprising the powder conveyance device according to claim 5.

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