JP2017032846A - Conveyance member, developing device, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a conveyance member, developing device, and image forming apparatus that can improve developer stirring performance.SOLUTION: A conveyance member comprises: a plurality of spiral blades that are formed spirally around a rotational shaft and conveys a conveyance target material in a rotational shaft direction through rotation of the rotational shaft; and discontinuous parts that divide the plurality of spiral blades so that the plurality of spiral blades are discontinuous in the shaft direction. The plurality of spiral blades have different diameters from each other on a cross section in a direction orthogonal to the rotational shaft.SELECTED DRAWING: Figure 5

Description

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

  In Patent Literature 1, a spiral is formed around the rotation axis, and the object to be conveyed is conveyed in the direction of the rotation axis by the rotation of the rotation axis, and overlaps in a cross section in a direction perpendicular to the rotation axis. A plurality of spiral blades having locations, and each of the spiral blades is divided into an upstream spiral blade and a downstream spiral blade, and the upstream spiral blade and the downstream spiral blade are rotated. A plurality of discontinuous portions arranged so as to have different phases around the axis, and the passage of the object to be conveyed that flows between the separated upstream spiral blade and the downstream spiral blade in the transport direction A conveying member provided with a regulating unit that regulates the amount is disclosed.

  In Patent Document 2, a plurality of spiral blades having a portion overlapping each other in a cross section in a direction perpendicular to the rotation axis, formed in a spiral shape around the rotation axis, The spiral blade includes a discontinuous portion that is divided into a first spiral blade and a second spiral blade that face each other so that the spiral blade is discontinuous in the extending direction. The spiral blade and the second spiral blade are arranged so that the phases around the rotation axis are different, and the spiral blade extends to at least one surface of the spiral blade adjacent in the circumferential direction of the rotation shaft. A developer stirring and conveying member having an inclined portion whose inclination changes with respect to the present direction is disclosed.

  In Patent Document 3, a multi-strand spiral blade having a plurality of spiral blades spirally wound around a common rotation axis, and the multi-strand spiral blade are discontinuous in the axial direction. A discontinuous portion that divides the spiral blade, and in the discontinuous portion, the upstream end portion and the downstream end portion of the multi-row spiral blade are arranged and formed so that the phases around the rotation axis are different. A developer stirring and conveying member is disclosed.

JP 2014-160162 A JP 2014-134619 A JP 2010-256429 A

  An object of the present invention is to provide a conveying member, a developing device, and an image forming apparatus that can improve the stirring performance of a developer.

  The present invention according to claim 1 is formed in a spiral shape around the rotation axis, and a plurality of spiral blades that convey the object to be conveyed in the rotation axis direction by the rotation of the rotation shaft, and the plurality of spiral blades in the axial direction Discontinuous portions that divide the plurality of spiral blades so as to be discontinuous, and the plurality of spiral blades have different diameters on a cross section in a direction orthogonal to the rotation axis. It is a conveying member.

  The present invention according to claim 2 is arranged such that the phase around the rotation axis of the end portion of the upstream spiral blade is different by 90 ° from the end portion of the upstream spiral blade across the discontinuous portion. It is a conveyance member of Claim 1.

  The present invention according to claim 3 is the conveying member according to claim 1 or 2, wherein the upstream-side spiral blade and the downstream-side spiral blade have the same diameter across the discontinuous portion.

  According to a fourth aspect of the present invention, the plurality of spiral blades are arranged so that phases thereof are different from each other by 180 ° in a cross section in a direction orthogonal to the rotation axis. It is a conveyance member as described in above.

  The present invention according to claim 5 is different from the first spiral blade, wherein the first spiral blade is spirally formed around the rotation axis and conveys the object to be conveyed in the rotation axis direction by the rotation of the rotation shaft. A second spiral blade formed in a spiral shape around the rotation shaft in phase, and transports an object to be transported in the direction of the rotation shaft by the rotation of the rotation shaft; the first spiral blade; and the second spiral blade; Includes a discontinuous portion that divides each of the first spiral blade and the second spiral blade so as to be discontinuous in the axial direction, and the second spiral blade includes the first spiral blade. It is a conveying member having a smaller diameter than the blade.

  According to a sixth aspect of the present invention, there is provided a developer holding body for holding a developer, a developer transported toward the developer holding body, a spiral formed around a rotation axis, and the rotation of the rotation axis. A plurality of spiral blades that convey the developer in the rotation axis direction, and a discontinuous portion that divides the plurality of spiral blades so that the plurality of spiral blades are discontinuous in the axial direction. The spiral blade is a developer replenisher that replenishes a transport member having different diameters on a cross section in a direction perpendicular to the rotation axis and a developer provided upstream of the transport member in the developer transport direction. A developing device.

  According to a seventh aspect of the present invention, there is provided a developer holding body for holding a developer, a developer transported toward the developer holding body, a spiral formed around a rotation axis, and the rotation of the rotation axis. A plurality of spiral blades that convey the developer in the rotation axis direction, and a discontinuous portion that divides the plurality of spiral blades so that the plurality of spiral blades are discontinuous in the axial direction. The spiral blade is a developer replenisher that replenishes a transport member having different diameters on a cross section in a direction perpendicular to the rotation axis and a developer provided upstream of the transport member in the developer transport direction. And an image forming unit that forms an image on a supplied recording medium.

  According to the first to fifth aspects of the present invention, the developer agitation performance can be improved as compared with the case where the plurality of spiral blades have the same diameter.

  According to the sixth aspect of the present invention, it is possible to provide a developing device capable of improving the stirring performance of the circulating developer and the replenished developer as compared with the case where the configuration of the present invention is not provided. it can.

  According to the seventh aspect of the present invention, it is possible to provide an image forming apparatus provided with a developing device with improved developer stirring performance as compared with the case where the configuration of the present invention is not provided.

1 is a cross-sectional view illustrating an image forming apparatus according to an embodiment of the present invention. It is sectional drawing which shows the developing device which concerns on one Embodiment of this invention. It is the sectional view on the AA line in FIG. It is a perspective view which shows the developer stirring conveyance member which concerns on one Embodiment of this invention. FIG. 5 is a schematic diagram for explaining a configuration of a developer stirring and conveying member illustrated in FIG. 4. 5A and 5B are schematic diagrams for explaining the configuration of the developer agitating and conveying member shown in FIG. 4, wherein FIG. 5A is a schematic diagram showing a rotation direction and an angle region of the developer agitating and conveying member, and FIG. It is a schematic diagram which shows the existing angle area | region of a spiral blade. FIG. 5 is a schematic diagram for explaining a mechanism for transporting a developer using the developer stirring and transporting member illustrated in FIG. 4.

Next, an embodiment for carrying out the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view of an image forming apparatus 10 as an embodiment of the present invention.

  The image forming apparatus 10 includes an image forming apparatus main body 12.

The upper surface of the image forming apparatus main body 12 is used as a discharge unit 14 from which a recording medium on which an image is formed is discharged.
In the image forming apparatus main body 12, an image forming unit 16 that forms an image to be transferred to a recording medium, a recording medium supply device 18 that supplies the recording medium to the image forming unit 16, and a supply from the recording medium supply device 18 A conveyance path 20 is provided for conveying the recorded recording medium to the discharge unit 14.

  The image forming unit 16 includes, for example, four developer image forming units 22Y, 22M, 22C, and 22K, an optical writing device 24, and a transfer device 26.

The developer image forming units 22Y, 22M, 22C, and 22K form developer images using Y (yellow), M (magenta), C (cyan), and K (black) developers, respectively.
Hereinafter, Y, M, C, and K corresponding to each color may be omitted and generically referred to as a developer forming unit 22 in some cases. The same applies to other configurations (photosensitive unit 28, developing device 30 and the like) corresponding to each color.

  Each of the developer image forming units 22Y, 22M, 22C, and 22K includes photoreceptor units 28Y, 28M, 28C, and 28K, and developing devices 30Y, 30M, 30C, and 30K.

The photoconductor units 28 are arranged in the order of the photoconductor units 28Y, 28M, 28C, and 28K from the rear side (left side in FIG. 1) of the image forming apparatus main body 12.
Each of the photoreceptor units 28Y, 28M, 28C, and 28K is used as an image forming structure, and each of these includes a photoreceptor drum 32Y, 32M, 32C, and 32K.
The photosensitive drum 32 is used as an image carrier.

  The developing devices 30Y, 30M, 30C, and 30K develop the latent images formed on the corresponding photosensitive drums 32Y, 32M, 32C, and 32K using the Y, M, C, and K developers stored therein, respectively. .

  The optical writing device 24 is used as a latent image forming device and irradiates the photosensitive drum 32 with light to form a latent image on the surface of each of the photosensitive drums 32Y, 32M, 32C, and 32K.

  The transfer device 26 includes an intermediate transfer belt 34 used as a transfer member, primary transfer rolls 36Y, 36M, 36C, and 36K used as primary transfer devices, and a secondary transfer roll 38 used as a secondary transfer device. And a cleaning device 40.

  The intermediate transfer belt 34 is endless, and is supported by, for example, five support rolls 34a, 34b, 34c, 34d, and 34e so that the intermediate transfer belt 34 can rotate in the direction indicated by the arrow in FIG. At least one of the support rolls 34a, 34b, 34c, 34d, and 34e is connected to a motor (not shown). The intermediate transfer belt 34 is rotationally driven by rotating by receiving drive transmission from the motor. Let

  The primary transfer rolls 36Y, 36M, 36C, and 36K respectively transfer the developer images formed on the front surfaces of the photosensitive drums 32Y, 32M, 32C, and 32K by the corresponding developing devices 30Y, 30M, 30C, and 30K. Transfer to the belt 34.

  The secondary transfer roll 38 transfers the Y, M, C, and K developer images transferred to the intermediate transfer belt 34 to a recording medium.

  The cleaning device 40 scrapes off the toner constituting the developer of each color remaining on the surface of the intermediate transfer belt 34 after the developer image of each color is transferred onto the recording medium by the secondary transfer roll 38. 42. The toner scraped off by the scraping member 42 is collected in the main body of the cleaning device 40.

  Further, in the image forming apparatus main body 12, a fixing device 44 that fixes the developer image transferred to the recording medium by the secondary transfer roll 38 to the recording medium is provided.

  The recording medium supply device 18 extracts the recording medium storage container 46 that stores the recording media in a stacked state, and the uppermost recording medium stored in the recording medium storage container 46, and the extracted recording medium is the image forming unit 16. A feed roll 48 that is fed out toward the head, a transport roll 50 that feeds the recording medium sent out from the feed roll 48, and a recording medium that is rolled up and transported in a state where a plurality of recording media are overlapped on the image forming unit 16. And a retard roll 52 for preventing this.

  The conveyance path 20 includes a main conveyance path 54 and a reverse conveyance path 56.

  The main conveyance path 54 conveys the recording medium supplied from the recording medium supply device 18 to the image forming unit 16 and discharges the recording medium on which the image is formed to the discharge unit 14. Along with the main conveyance path 54, in order from the upstream side in the recording medium conveyance direction, a feed roll 48, a conveyance roll 50, a retard roll 52, a registration roll 58, a transfer unit 60, a fixing device 44, and a discharge roll 62 Is arranged.

  The registration roll 58 adjusts the timing (timing) of transporting the recording medium to the transfer unit 60. The registration roll 58 temporarily stops the leading end portion of the recording medium conveyed from the recording medium supply device 18 side, and sends the recording medium toward the transfer unit 60 so as to coincide with the image formation timing.

  The fixing device 44 includes a heating roll 44a and a pressure roll 44b, and heats and pressurizes the recording medium passing between the heating roll 44a and the pressure roll 44b, thereby fixing the developer image on the recording medium. To do.

  The discharge roll 62 discharges the recording medium on which the developer is fixed by the fixing device 44 to the discharge unit 14.

The reversal conveyance path 56 is re-registered so that the developer image is transferred to one surface of the recording medium by the transfer unit 60 and then reversed so that the developer image is transferred to the opposite surface. It is used as a transport path for transporting this recording medium toward the head.
For example, two reverse conveyance rolls 64 a and 64 b are arranged along the reverse conveyance path 56.

  In the case of duplex printing, the recording medium conveyed from the main conveyance path 54 to the discharge roll 62 is reversed by the reverse rotation of the discharge roll 62 with the rear end portion sandwiched between the discharge rolls 62. It is supplied to the conveyance path 56. The recording medium supplied to the reverse conveyance path 56 is conveyed to a position upstream of the registration roll 58 by the reverse conveyance rolls 64a and 64b.

Next, details of the developing device 30 will be described. The developing devices 30Y, 30M, 30C, and 30K have the same configuration although the corresponding colors are different. Therefore, the developing devices 30 will be described below.
2 shows a cross-sectional view of the developing device 30, and FIG. 3 shows a cross-sectional view taken along line AA of FIG.

  The developing device 30 is a two-component developing device that develops a latent image using a two-component developer composed of toner and a carrier, and has a developing device main body 66, and the developer is accommodated in the developing device main body 66. ing.

  A developing roll 68 used as a developer holder is mounted in the developing device main body 66. The developing roll 68 rotates in the direction of the arrow shown in FIG. 2 to supply the developer held on the surface to the photosensitive drum 32 (see FIG. 1), and the latent image formed on the surface of the photosensitive drum 32 is supplied. develop.

The inside of the developing device main body 66 is divided into, for example, two spaces by one partition member 70, and the divided spaces are developer transport paths 72 and 74, respectively. The developer transport paths 72 and 74 are used as paths through which the developer is transported within the developing device main body 66.
In the developer conveyance paths 72 and 74, developer agitating and conveying members 76 and 78 as conveying members for conveying the developer while stirring are mounted, respectively.

Here, the developer agitating / conveying member 76 is a supply auger provided on the developing roll 68 side and having a function of supplying the developer to the developing roll 68 in addition to the function of stirring and mixing toner.
The developer stirring / conveying member 78 is an admix (stirring) auger that stirs and mixes toner supplied to an existing two-component developer.

A developer supply port 79 is opened on the upstream side of the developer conveyance path 74 of the developing device main body 66, and a toner density sensor (not shown) is disposed on the downstream side.
The toner T is supplied from the developer supply section 81 into the developing device main body 66 through the developer supply port 79 and is circulated and conveyed by the developer agitating and conveying members 76 and 78 while agitating and mixing the two-component developer. The

  4 is a perspective view of the developer agitating / conveying member 78. FIG. 5 is a schematic diagram for explaining the configuration of the developer agitating / conveying member 78. FIG. 4 (a) shows the ridge line of the spiral blade as a straight line. It is the figure shown roughly in the shape, Comprising: (b) is a figure which shows the cut surface of the AA sectional view taken on the line (a).

  The developer agitating / conveying member 78 includes a shaft 84 that is a rotation shaft, a first spiral blade 86 a that is formed in a spiral shape around the shaft 84, and has a portion that overlaps with the first spiral blade 86 a and the first spiral blade 86 a. Two spiral blades composed of two spiral blades 86b are provided. The upstream side of the developer agitating / conveying member 78 in the developer conveying direction is formed by a single spiral blade 85. The developer stirring and conveying member 78 conveys the developer in the conveying direction by the rotation of the shaft 84.

  The second spiral blade 86b has a smaller diameter than the first spiral blade 86a.

  The first spiral blade 86a and the second spiral blade 86b are formed at the same pitch with respect to the rotation shaft 84, and are disposed so that the phases around the rotation shaft 84 are different from each other by 180 °.

  In the portion where the first spiral blade 86a and the second spiral blade 86b are provided to overlap each other, discontinuous portions FR in which these spiral blades are discontinuous in the axial direction are periodically formed.

  FIG. 6A is a schematic diagram showing a rotation direction and an angle region of the developer stirring and conveying member 78, and FIG. 6B is a schematic diagram showing an existence angle region of the spiral blade along the axial direction. .

  As schematically shown in FIG. 6A, the rotational directions of the first spiral blade 86a and the second spiral blade 86b according to the present embodiment are counterclockwise as viewed from BB in FIG. The existence area of the first spiral blade 86a and the second spiral blade 86b is set as shown in FIG. 6B. Here, the horizontal axis in FIG. 6 (b) indicates the position in the axial direction, and the vertical axis in FIG. 6 (b) indicates the first spiral blade when the angular region is set as shown in FIG. 6 (a). 86a and the present angular area of the second spiral blade 86b are shown. Of the two spiral blades 86, the thick line in FIG. 6B indicates the first spiral blade 86a, and the thin line indicates the second spiral blade having a 180 ° mounting phase different from that of the first spiral blade 86a. 86b is shown.

  As shown in FIG. 6B, in the discontinuous portion FR (in this example, four locations X (4), X (8), X (12), and X (16) in the figure) The upstream end portions 86au and 86bu and the downstream end portions 86ad and 86bd of the first spiral blade 86a and the second spiral blade 86b facing each other across the continuous portion FR are 90 ° out of phase with each other (90 ° It is arranged so as to shift. For example, in the discontinuous portion FR (4) in X (4), the upstream end 86au of the first spiral blade 86a is disposed at a position of 90 °, whereas the downstream end 86ad is disposed at a position of 180 °, and the mounting phase difference between them is set to 90 °. The upstream end 86bu of the second spiral blade 86b is disposed at a position of 270 °, whereas the downstream end 86bd is at a position of 360 ° (0 °). It is arrange | positioned and it sets so that the attachment phase difference of both may be set to 90 degrees. Similarly, in the other discontinuous portions FR (8), FR (12), and FR (16), the upstream ends 86au and 86bu and the downstream sides of the spiral blades 86a and 86b facing each other with the discontinuous portion FR interposed therebetween. It is set and arranged so that the attachment phase with the end portions 86ad and 86bd differs by 90 °.

  Further, the upstream end portion 84au of the first spiral blade 86a and the downstream end portion 86bd of the second spiral blade 86b facing each other across the discontinuous portion FR are 90 ° out of phase with each other (90 ° shifted). So as to be arranged). For example, in the discontinuous portion FR (4) in X (4), the upstream end 86au of the first spiral blade 86a is disposed at a position of 90 °, whereas the second spiral The downstream end 86bd of the blade 86b is disposed at a position of 0 ° (360 °), and is set so that the mounting phase difference between them is 90 °. The upstream end 86bu of the second spiral blade 86b is disposed at a position of 270 °, while the downstream end 86ad of the first spiral blade 86a is positioned at a position of 180 °. The mounting phase difference between them is set to 90 °. Similarly, in the other discontinuous portions FR (8), FR (12), and FR (16), the upstream end 86au and the downstream end of the spiral blades 86a and 86b that are opposed to each other with the discontinuous portion FR interposed therebetween. 86bd, the upstream end portion 86bu and the downstream end portion 86ad are set and arranged so as to be different from each other by 90 °.

  That is, the spiral blades having the same diameter are set and arranged so as to overlap with each other with a mounting phase of 90 ° across the discontinuous portion FR, and the spiral blades of the same diameter are set and arranged close to each other with the discontinuous portion FR interposed therebetween. .

  That is, the developer agitating / conveying member 78 according to the present embodiment has two spiral blades 86a and 86b that are 180 ° out of phase, and each of the opposing spiral blades 86a and 86b in the discontinuous portion FR. The end portions are set and arranged so that the phases thereof are different by 90 °.

  As compared with the configuration in which a plurality of spiral blades are provided in this manner and a single spiral blade is provided, the transport surface for transporting the developer is doubled in a cross section perpendicular to the axial direction, and the developer transport capability in the axial direction is increased. Is increased.

Next, the conveyance of the developer by the developer stirring and conveying member 78 will be described with reference to FIGS. 6 and 7 described above.
FIG. 7 shows the developer agitating / conveying member 78 transported by spiral blades in the 1/4 rotation, 1/2 rotation, 3/4 rotation, and 1 rotation states in the rotation axis direction of the developer agitating / conveying member 78. It is the figure which showed typically the developed developer.
Here, the developer conveyed by the first spiral blade 86a and the second spiral blade 86b of the developer stirring and conveying member 78 is transferred from the upstream side in the developer conveying direction (right end in FIG. 7, X = 0) to D1. , D2, D3, D4.

(1) 1/4 rotation The developer agitating and conveying member 78 rotates 1/4 and the development conveyed by the upstream side of the first spiral blade 86a on the upstream side of the discontinuous portion FR (4) in the developer conveying direction. The developer D1, the developer D2 transported by the second spiral blade 86b, and the developer D4 transported by the first spiral blade 86a downstream of the discontinuous portion FR (4) in the developer transport direction are 1/4 pitch. It is conveyed for minutes. In the developer D3, a part of the developer conveyed downstream of the first spiral blade 86a on the upstream side in the developer transport direction of the discontinuous portion FR (4) is downstream of the second spiral blade 86b. Although it is delivered to the end portion 86bd and merges with the developer D4, the remaining first spiral blade 86a on the upstream side of the discontinuous portion FR (4) is interrupted at the upstream end portion 86au, and the discontinuous portion FR (4). The developer D3 is not conveyed.

(2) 1/2 rotation When the developer agitating / conveying member 78 is further rotated 1/4, the developer D3 remaining in the discontinuous portion FR (4) is moved to the upstream end of the next second spiral blade 86b. The second spiral blade 86b has a small outer diameter and cannot transport all the developer D3. Therefore, the developer D3 is divided into a developer D3-1 conveyed by the second spiral blade 86b and a developer D3-2 that stays in place. Further, the developer D3-2 staying in place is mixed with the developer D2 conveyed to the second spiral blade 86b to become the developer D5 ((D3-2) + D2 = D5). , The discontinuous portion FR (4) remains unconveyed as developer D5. Developers D1, D3-1, and D4 are respectively conveyed by 1/4 pitch.

(3) 3/4 rotation If the 1/4 rotation is further performed, the second spiral blade 86b on the upstream side of the discontinuous portion FR (4) is interrupted at the upstream end portion 86bu, and becomes the discontinuous portion FR (4). It remains without being conveyed as developer D5. Developers D1, D3-1, and D4 are respectively conveyed by 1/4 pitch.

(4) 1 rotation When the rotation is further rotated 1/4, the developer D5 starts the downstream end 86ad of the first spiral blade 86a on the downstream side of the discontinuous portion FR (4) in the developer transport direction. It is conveyed by 4 pitches. Developers D1 and D3-1 are also conveyed by a quarter pitch. The developer D4 remains without being conveyed as the developer D4 in the discontinuous portion FR (8).

  As described above, there is a partial difference in the time during which the developer D3 once retained at the discontinuous portion is delivered to the downstream spiral blade. As a result, while the developer stirring / conveying member 78 makes one rotation, even if the developer is in the same position, such as developer D3-1 and developer D3-2 (D5), the moving distance is ½ pitch. There is a difference. That is, in the developing device, the developer conveyed by the double spiral blades having different diameters is speed-differed to stir the developer, and the toner distribution in the axial direction is made uniform.

  In the present embodiment, the configuration having two spiral blades has been described. However, the present invention is not limited to this, and the present invention can also be applied to a configuration having a plurality of spiral blades.

DESCRIPTION OF SYMBOLS 10 Image forming apparatus 12 Image forming apparatus main body 16 Image forming part 30 Developing device 76, 78 Developer stirring conveyance member 81 Developer supply part 84 Rotating shaft 86a 1st spiral blade 86b 2nd spiral blade FR Discontinuous part

Claims (7)

A plurality of spiral blades that are formed in a spiral shape around the rotation axis, and that convey the object to be conveyed in the direction of the rotation axis by the rotation of the rotation axis;
The plurality of spiral blades, the discontinuous portion that divides the plurality of spiral blades so as to be discontinuous in the axial direction,
The plurality of spiral blades have different diameters on a cross section in a direction orthogonal to the rotation axis.   The conveying member according to claim 1, wherein a phase around an axis of rotation of an end portion of the spiral blade on the downstream side from an end portion of the spiral blade on the downstream side is arranged so as to be 90 ° different from each other across the discontinuous portion.   The conveying member according to claim 1, wherein the upstream spiral blade and the downstream spiral blade in the axial direction across the discontinuous portion have the same diameter.   The conveying member according to any one of claims 1 to 3, wherein the plurality of spiral blades are arranged so that phases thereof are different from each other by 180 degrees in a cross section in a direction orthogonal to the rotation axis. A first spiral blade that is formed in a spiral shape around the rotation axis, and conveys the object to be conveyed in the direction of the rotation axis by the rotation of the rotation axis;
A second spiral blade formed in a spiral shape around the rotation axis in a phase different from that of the first spiral blade, and transporting an object to be conveyed in the direction of the rotation axis by rotation of the rotation shaft;
A discontinuous portion that divides the first spiral blade and the second spiral blade such that the first spiral blade and the second spiral blade are discontinuous in the axial direction. ,
The second spiral blade has a diameter smaller than that of the first spiral blade. A developer holder for holding the developer;
A plurality of spiral blades that convey the developer toward the developer holder, spirally formed around a rotation axis, and convey the developer in the rotation axis direction by rotation of the rotation shaft; and the plurality of spiral blades A plurality of discontinuous portions that divide the plurality of spiral blades so as to be discontinuous in the axial direction, and the plurality of spiral blades are mutually cross-sectional in a direction perpendicular to the rotation axis. Conveying members having different diameters;
A developer replenishment section for replenishing the developer provided on the upstream side in the developer transport direction of the transport member;
A developing device. A developer holding body that holds the developer, and the developer is conveyed toward the developer holding body, is formed in a spiral shape around the rotation axis, and the developer is conveyed in the rotation axis direction by the rotation of the rotation axis. A plurality of spiral blades, and a discontinuous portion that divides the plurality of spiral blades such that the plurality of spiral blades are discontinuous in the axial direction, and the plurality of spiral blades are A developing device having a conveying member having different diameters on a cross section in a direction orthogonal to each other, and a developer replenishing unit that replenishes the developer provided upstream of the conveying member in the developer conveying direction;
An image forming unit for forming an image on the supplied recording medium;
An image forming apparatus.

Images