Developing device, process cartridge, and image formation device

Abstract

To provide a sheet-like member so as to separate a developer roller from a developer supply rotor even if a facing distance between the developing roller and the developer supply rotor is short.SOLUTION: A removable sheet-like member 26r is provided that forms a developer pre-accommodation part having developer G accommodated inside of a first conveyance screw 26b1 side (a developer supply rotor) in a developing device 26, separating a developing roller 26a from the first conveyance screw 26b1 such that the developer G accommodated in the developing device 26 does not leak outside. Then, when viewed at a cross section orthogonal to rotating shaft parts of the developing roller 26a or the first conveyance screw 26b1, the sheet-like member 26r is arranged so as to cross at 90±10 degrees with respect to a virtual line S connecting a rotation center of the developing roller 26a and a rotation center of the first conveyance screw 26b1.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a developing device that develops a latent image formed on an image carrier such as a photosensitive drum, and to a process cartridge and an image forming apparatus that include the same. [Background technology]

[0002] Conventionally, in a developing device that is detachably installed in an image forming device such as a copier or printer, a technology has been known in which a sheet-like member (sealing sheet) is detachably provided to isolate the space containing the developer as a closed space so that the developer previously contained inside the new developing device at the time of shipping from the factory does not leak outside the developing device during transportation, etc. (see, for example, Patent Document 1).

[0003] In detail, before the developing device is attached to the image forming apparatus main body and put into use, a sheet-like member is provided to separate the inside of the developing device so as to form a closed space containing the developer, and separate the developing roller from the first conveying screw (developer supply rotor) to prevent the developer pre-stored (preset) inside from leaking to the outside. Before use in the image forming apparatus, the sheet-like member is pulled out in the longitudinal direction (the direction corresponding to the rotational axis of the developing roller), so that the developer is contained entirely inside the developing device, and the developing process (image formation) can be carried out by the developing device. Summary of the Invention [Problem to be solved by the invention]

[0004] In the conventional technology, a sheet-like member is provided to separate the developing roller and the developer supply rotor, so the opposing distance between the developing roller and the developer supply rotor is set relatively large, which results in an increase in the size of the developing device and makes it impossible to reduce the amount of developer for preset.

[0005] This invention has been made to solve the above-mentioned problems, and aims to provide a developing device, a process cartridge, and an image forming apparatus in which a sheet-like member can be provided to separate the developing roller and the developer supply rotor even if the opposing distance between the developing roller and the developer supply rotor is short. [Means for solving the problem]

[0006] The developing device of this invention is a developing device that is detachably installed in the image forming device main body and contains developer inside, and comprises a developing roller that carries developer and develops a latent image formed on the surface of an image carrier, a developer supply rotor that faces the developing roller and rotates in a predetermined direction to supply developer to the developing roller, and a removable sheet-like member that separates the developing roller and the developer supply rotor to prevent the developer contained in the developing device from leaking to the outside, and forms a developer pre-storage section inside the developer supply rotor side of the developing device, and is positioned so that when viewed in a cross section perpendicular to the rotational axis of the developing roller or the developer supply rotor, the sheet-like member intersects at 90±10 degrees with an imaginary line connecting the center of rotation of the developing roller and the center of rotation of the developer supply rotor. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a developing device, a process cartridge, and an image forming apparatus in which a sheet-like member can be provided to separate the developing roller and the developer supply rotor even if the opposing distance between the developing roller and the developer supply rotor is short. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is an overall configuration diagram showing an image forming apparatus according to an embodiment of the present invention; [Figure 2] FIG. [Figure 3] FIG. 2 is a longitudinal view of the developing device. [Figure 4]FIG. 2 is an enlarged view showing a main part of the developing device. [Figure 5] FIG. 2 is a top view showing the base portion of the lower developing case in the longitudinal direction. [Figure 6] FIG. 4 is an enlarged view showing a main part of a developing device as a comparative example. [Figure 7] 10 is a diagram showing the positional relationship between a gear train and a sheet-like member in a developing device according to a first modified example. FIG. [Figure 8] FIG. 10 is an enlarged view showing a main part of a longitudinal end portion of a developing device as a second modified example. [Figure 9] FIG. 11 is an enlarged view showing a main part of a developing device according to a third modified example. [Figure 10] FIG. 10 is an enlarged view showing a main part of a developing device according to a fourth modified example. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In each drawing, the same or corresponding parts are designated by the same reference numerals, and redundant explanations will be appropriately simplified or omitted.

[0010] First, the overall configuration and operation of an image forming apparatus 1 will be described with reference to FIG. The image forming apparatus 1 in this embodiment is a tandem color image forming apparatus in which a plurality of process cartridges 20Y, 20M, 20C, and 20BK are arranged side by side so as to face an intermediate transfer belt 40. In addition, a developing device 26 (see FIG. 2) is installed so as to face the photosensitive drums 21 of the plurality of process cartridges 20Y, 20M, 20C, and 20BK.

[0011] In Figure 1, 1 indicates the main body of a color copier as an image forming device, 2 indicates a document transport unit that transports a document to a document reading unit 3, 3 indicates a document reading unit that reads image information from the document, and 4 indicates a writing unit (exposure unit) that emits laser light based on input image information. Also, 20Y, 20M, 20C, and 20BK indicate process cartridges corresponding to the respective colors (yellow, magenta, cyan, and black), and 40 indicates an intermediate transfer belt onto which toner images of multiple colors are transferred in an overlapping manner. Also, 61 denotes a paper feed device in which sheets P such as paper are stored, 65 denotes a secondary transfer roller that transfers the toner image formed on the intermediate transfer belt 40 to the sheet P, and 66 denotes a fixing device that fixes the unfixed image on the sheet P. Also, 70 denotes a toner container for replenishing toner of each color to each developing device 26 corresponding to the multiple process cartridges 20Y, 20M, 20C, and 20BK, and 80 denotes a waste toner collection container in which untransferred toner collected by the cleaning device 23 (see Figure 2) or the intermediate transfer belt cleaning device 81 is collected as waste toner.

[0012] 2, each of the process cartridges 20Y, 20M, 20C, and 20BK integrates a photosensitive drum 21 as an image carrier, a charging device 22, and a cleaning device 23. When each of the process cartridges 20Y, 20M, 20C, and 20BK reaches the end of its life, it is removed from the image forming apparatus main body 1 and replaced with a new one. Each developing device 26 is disposed opposite the photosensitive drum 21 of each process cartridge 20Y, 20M, 20C, and 20BK. When the developing device 26 reaches the end of its life, it is removed from the image forming apparatus main body 1 and replaced with a new one. The operation of attaching and detaching the developing device 26 to and from the image forming apparatus main body 1 and the operation of attaching and detaching the process cartridges 20Y, 20M, 20C, and 20BK to and from the image forming apparatus main body 1 can be performed separately and independently. A toner image of each color (yellow, magenta, cyan, black) is formed on the photosensitive drum 21 (image carrier) of each of the process cartridges 20Y, 20M, 20C, and 20BK.

[0013] Hereinafter, the operation of the image forming apparatus during normal color image formation will be described. First, the document is transported from the document table by the transport rollers of the document transport unit 2 and placed on the contact glass of the document reading unit 3. Then, the document reading unit 3 optically reads the image information of the document placed on the contact glass. Then, the image information for each color of yellow, magenta, cyan, and black is sent to the writing unit 4. Then, from the writing unit 4, laser light L (exposure light) based on the image information for each color is irradiated onto the surface of the photosensitive drum 21 (see FIG. 2) of the corresponding process cartridge 20Y, 20M, 20C, 20BK.

[0014] Meanwhile, each of the four photosensitive drums 21 rotates clockwise in FIGS. 1 and 2. First, the surface of each photosensitive drum 21 is uniformly charged at a position facing the charging device 22 (charging roller) (charging process). In this way, a charging potential is formed on the photosensitive drum 21. Thereafter, the charged surface of each photosensitive drum 21 reaches a position where a laser beam is irradiated by each writing unit 4, and an electrostatic latent image based on image information is formed at that position (exposure process).

[0015] The laser light corresponding to the yellow component is irradiated onto the surface of the photosensitive drum 21 of the first process cartridge 20Y from the left side of the drawing. At this time, the laser light of the yellow component is scanned in the direction of the rotation axis (main scanning direction) of the photosensitive drum 21 by a polygon mirror rotating at high speed. In this way, an electrostatic latent image corresponding to the yellow component is formed on the photosensitive drum 21 after it has been charged by the charging device 22. Similarly, the cyan laser light is irradiated onto the surface of the photosensitive drum 21 of the process cartridge 20C, which is the second from the left on the paper, and an electrostatic latent image of the cyan component is formed. The magenta laser light is irradiated onto the surface of the photosensitive drum 21 of the process cartridge 20M, which is the third from the left on the paper, and an electrostatic latent image of the magenta component is formed. The black laser light is irradiated onto the surface of the photosensitive drum 21 of the process cartridge 20BK, which is the fourth from the left on the paper, and an electrostatic latent image of the black component is formed.

[0016] Thereafter, the surface of the photosensitive drum 21 on which the electrostatic latent image of each color is formed reaches a position facing the developing device 26. Then, toner of each color is supplied from each developing device 26 onto the photosensitive drum 21, and the latent image on the photosensitive drum 21 is developed (this is the developing process). Thereafter, the surfaces of the photosensitive drums 21 after the development process reach positions facing the intermediate transfer belt 40. Here, primary transfer rollers 24 are installed at each of the facing positions so as to abut against the inner circumferential surface of the intermediate transfer belt 40. Then, at the positions of the primary transfer rollers 24, the toner images of each color formed on the photosensitive drums 21 are transferred onto the intermediate transfer belt 40 in order, superimposed on top of each other (this is the primary transfer process).

[0017] After the primary transfer process, the surfaces of the photosensitive drums 21 reach a position facing the cleaning devices 23. The cleaning devices 23 then collect untransferred toner remaining on the photosensitive drums 21 (this is the cleaning process). The untransferred toner collected by the cleaning devices 23 passes through a waste toner transport path (not shown) and is collected in the waste toner collection container 80. Thereafter, the residual potential on the surface of the photosensitive drum 21 is removed at the position of the charge removal device, and a series of image forming processes on the photosensitive drum 21 is completed.

[0018] Meanwhile, the surface of the intermediate transfer belt 40 onto which the images of each color on the photosensitive drum 21 are transferred and superimposed runs in the direction of the arrow in the figure and reaches the position of the secondary transfer roller 65. Then, at the position of the secondary transfer roller 65, the full-color image on the intermediate transfer belt 40 is secondarily transferred onto the sheet P (secondary transfer process). Thereafter, the surface of the intermediate transfer belt 40 reaches the position of the intermediate transfer belt cleaning device 81. Then, the untransferred toner on the intermediate transfer belt 40 is collected by the intermediate transfer belt cleaning device 81, and the series of transfer processes on the intermediate transfer belt 40 is completed. The untransferred toner collected by the intermediate transfer belt cleaning device 81 passes through a waste toner transport path (not shown) and is collected in a waste toner collection container 80 .

[0019] Here, the sheet P conveyed to the position of the secondary transfer roller 65 is conveyed from the paper feeder 61 via the registration roller 64 and the like. More specifically, a sheet P fed by a paper feed roller 62 from a paper feed device 61 that stores sheets P passes through a conveyance path and is then guided to the position of a registration roller 64. The sheet P that has reached the position of the registration roller 64 is conveyed toward the position of a secondary transfer roller 65 in synchronization with the toner image on the intermediate transfer belt 40.

[0020] Thereafter, the sheet P onto which the full-color image has been transferred is guided to the position of the fixing device 20. Then, in the fixing device 20, the color image is fixed onto the sheet P at the nip between a fixing roller and a pressure roller. After the fixing process, the sheet P is discharged as an output image outside the apparatus main body 1 by a discharge roller 69, and then stacked on the discharge tray 5, completing a series of image forming processes (printing).

[0021] Next, the image forming unit of the image forming apparatus will be described in detail with reference to FIGS. The four image forming units installed in the image forming apparatus main body 1 have almost the same structure except for the color of the toner used in the image forming process, so they are illustrated without the alphabetical symbols (Y, M, C, BK) for components such as process cartridges and developing devices.

[0022] As shown in FIG. 2, the process cartridge 20 mainly includes a photosensitive drum 21 as an image carrier, a charging device 22, and a cleaning device 23 housed integrally in a case. The photosensitive drum 21 is a negatively charged organic photosensitive member, and is formed by providing a photosensitive layer and the like on a drum-shaped conductive support. The charging device 22 is a charging roller made of a conductive core metal and a medium-resistance elastic layer coated on the outer periphery thereof. A predetermined voltage is applied to the charging device 22 (charging roller) from a power supply unit, thereby uniformly charging the surface of the opposing photosensitive drum 21. The cleaning device 23 is equipped with a cleaning blade 25a and a cleaning roller 25b that come into contact with the photosensitive drum 21. The cleaning blade 25a is made of a rubber material such as urethane rubber, and comes into contact with the surface of the photosensitive drum 21 at a predetermined angle and with a predetermined pressure. The cleaning roller 25b is a brush roller with brush bristles arranged around a core metal.

[0023] As shown in Figures 2 and 3, the developing device 26 is mainly composed of a developing roller 26a as a developer carrier, a first transport screw 26b1 (transport screw) as a developer supply rotor facing the developing roller 26a, a second transport screw 26b2 facing the first transport screw 26b1 via a partition member 26e, and a doctor blade 26c as a developer regulating member facing the developing roller 26a below and regulating the amount of developer carried on the developing roller 26a.

[0024] The developing device 26 contains a developer (a two-component developer containing additives and the like) made up of a carrier and a toner. In this embodiment, the average particle size of the toner is set to about 5.2 μm, the average particle size of the carrier is set to about 35 μm, the toner concentration is set to about 7 wt %, and the amount of developer in the developing device 26 is set to about 250 g.

[0025] The developing roller 26a is configured to form a developing area by opposing the photosensitive drum 21 with a small gap (developing gap) therebetween. As shown in Fig. 3, the developing roller 26a is composed of a magnet 26a1 that is fixed inside and forms multiple magnetic poles H1 to H5 (see Fig. 4) on the outer circumferential surface of the roller, and a sleeve 26a2 that rotates around the magnet 26a1.

[0026] 4, the drawing-up magnetic pole H5 (located at a position facing the doctor blade 26c (or near that position)) acts on the carrier as a magnetic body, drawing up the developer G accommodated in the first transport path B1 (see FIG. 2) onto the developing roller 23a. A portion of the developer G carried on the developing roller 23a is scraped off at the position of the doctor blade 26c (see FIG. 2) and returned to the first transport path B1. Meanwhile, at the position of the doctor blade 26c where the magnetic force of the drawing-up magnetic pole H5 acts, the developer G carried on the developing roller 26a passes through the doctor gap between the doctor blade 26c and the developing roller 26a, and stands up at the position of the main magnetic pole H1, becoming a magnetic brush in the development area and sliding against the photosensitive drum 21. In this way, the toner in the developer G carried on the developing roller 26a adheres to the latent image on the photosensitive drum 21. After that, the developer G that has passed the position of the main magnetic pole H1 is transported between the developer upper case 26k and the developer G by multiple transport magnetic poles H2 and H3, and then transported to the position of the developer releasing magnetic pole H4. Then, at the position of the developer releasing magnetic pole H4, a repulsive magnetic field (a magnetic field that acts in a direction away from the developing roller 26a) acts on the carrier, causing the developer G that has been carried on the developing roller 26a after the development process to be detached from the developing roller 26a. The detached developer G falls into the first transport path B1 and is transported downstream of the first transport path B1 by the first transport screw 26b1 (see FIGS. 2 and 3).

[0027] 2 and 3, the first and second transport screws 26b1 and 26b2 transport the developer G contained inside the developing device 26 in the longitudinal direction (direction of the rotation axis) to form a circulation path (the circulation path indicated by the dashed arrow in FIG. 3). That is, a circulation path for the developer is formed by the first transport path B1 formed by the first transport screw 26b1 and the second transport path B2 formed by the second transport screw 26b2. The first transport path B1 and the second transport path B2 are separated by a partition member 26e serving as a wall, and both longitudinal ends of the two transport paths B1 and B2 communicate with each other via communication openings 26f and 26g. Specifically, referring to FIG. 3, the upstream end of the first transport path B1 in the transport direction communicates with the downstream end of the second transport path B2 in the transport direction via the first communication opening 26f. Furthermore, the downstream end of the first transport path B1 in the transport direction communicates with the upstream end of the second transport path B2 in the transport direction via the second communication opening 26g. In other words, the partition member 26e is disposed at a position excluding both longitudinal ends.

[0028] The first transport screw 26b1 (first transport path B1) is disposed so as to face the developing roller 26a diagonally downward, and the second transport screw 26b2 (second transport path B2) is disposed so as to face the first transport screw 26b1 (first transport path B1) via a partition member 26e (wall portion). The first transport screw 26b1 transports the developer in the rotation axis direction (longitudinal direction), while supplying the developer toward the developing roller 26a and recovering the post-development developer that has separated from the developing roller 26a. The second transport screw 26b2 agitates and mixes the post-development developer transported from the first transport path B1 with fresh toner supplied from the supply port 26d while transporting them in the longitudinal direction. In this embodiment, the two conveying screws 26b1 and 26b2 are arranged side by side in the horizontal direction. Each of the two conveying screws 26b1 and 26b2 has a rotation shaft portion 26b11 and a screw portion 26b12 and a screw portion 26b22 wound around the rotation shaft portion 26b11 and a screw portion 26b21 (shaft portion), and is driven to rotate at a rotation speed of about 600 rpm.

[0029] 2, in this embodiment, the developing device 26 is provided with an upper developing case 26k and a lower developing case 26j as a developing case (housing). The lower developing case 26j as a developing case is a casing that serves as the base of the developing device 26, and rotatably holds the developing roller 26a and the first and second conveying screws 26b1 and 26b2, as well as the doctor blade 26c. On the other hand, the upper developer case 26k is disposed above the lower developer case 26j (developing roller 26a). In particular, the upper developer case 26k is disposed so as to cover the lower developer case 26j (developing roller 26a). The upper developer case 26k is configured to be detachable from the lower developer case 26j, which holds the developing roller 26a, the conveying screws 26b1 and 26b2, and the doctor blade 26c, by snapping or screwing.

[0030] The image forming process described above will now be further explained, focusing on the development process. Developing roller 26a rotates in a predetermined rotation direction (counterclockwise direction indicated by the arrow in FIG. 2). As shown in FIG. 3, the developer in developing device 26 is circulated in the longitudinal direction while being stirred and mixed with toner supplied from toner container 70 through toner supply port 26d via the toner supply path by rotation of first transport screw 26b1 and second transport screw 26b2, which are arranged with partition member 26e interposed therebetween (circulation in the direction of the dashed arrow in FIG. 3). The toner, which has been frictionally charged and attracted to the carrier, is then lifted up onto the developing roller 26a together with the carrier by the developer lift-up pole H5 formed on the developing roller 26a. The developer carried on the developing roller 26a is transported in the direction of the arrow in FIG. 2 until it reaches a position facing the doctor blade 26c. The developer on the developing roller 26a is then adjusted to an appropriate amount at this position and then transported to a position facing the photosensitive drum 21 (the development area). The toner is then attracted to the latent image formed on the photosensitive drum 21 by the electric field formed in the development area. The developer remaining on the developing roller 26a then reaches above the first transport path B1 as the sleeve rotates and is detached from the developing roller 26a at this position. The electric field in the development area is formed by a predetermined voltage (development bias) applied to the developing roller 26a by a development power supply and a surface potential (latent image potential) formed on the surface of the photosensitive drum 21 during the charging and exposure processes.

[0031] The toner in the toner container 70 is appropriately replenished into the developing device 26 from the replenishing port 26d via a toner replenishing path (not shown) as the toner in the developing device 26 is consumed. The consumption of the toner in the developing device 26 is detected by a toner concentration sensor (not shown) that magnetically detects the toner concentration of the developer in the developing device 26 (the proportion of toner in the developer). The supply port 26d is provided at one end of the second transport screw 26b2 in the longitudinal direction (the left-right direction in FIG. 3), above the second transport screw 26b2 (second transport path B2).

[0032] The configuration and operation of the developing device 26 (image forming apparatus 1), which is a feature of this embodiment, will be described in detail below. The developing device 26 in this embodiment is installed so as to be detachable (replaceable) from the image forming apparatus main body 1, and is replaced with a new one (including recycled products) at a predetermined replacement cycle. 2 and other figures, the developing device 26 has the developing roller 26a, and the first and second transport screws 26b1 and 26b2 serving as developer supply rotors rotatably mounted in the lower developing case 26j (developing case). In addition, the developing device 26 has the doctor blade 26c mounted in the lower developing case 26j as a developer regulating member that faces the developing roller 26a disposed obliquely above the first transport screw 26b1 (developer supply rotor) below and regulates the amount of developer G carried on the surface of the developing roller 26a.

[0033] Referring now to FIG. 4, the developing device 26 in this embodiment is provided with a sheet-like member 26r (removably configured) that separates the developing roller 26a and the first transport screw 26b1 (developer supply rotor) to form a developer pre-storage section (which is generally a closed space) in which the developer G is stored inside the first transport screw 26b1 side of the developing device 26 (the first and second transport paths B1 and B2) so that the developer G stored in the developing device 26 (which is pre-filled at the time of shipment from the factory) does not leak out until use in the image forming apparatus main body 1 begins.

[0034] Specifically, the sheet-like member 26r is made of a transparent resin material such as an OHP sheet or Mylar having a thickness of about 0.1 to 0.5 mm, and is formed in a substantially rectangular shape so as to extend in the direction of the rotation axis (the direction of the rotation axis of the developing roller 26a and the first and second transport screws 26b1 and 26b2, which is the left-right direction in FIG. 5). The sheet-like member 26r is attached (adhered) to the base portion 26j1 of the lower developing case 26j by double-sided tape, heat fusion, or the like so as to cover an opening 26j10 (see FIG. 5) formed in the base portion 26j1 (see FIG. 5) to communicate between the space in which the developing roller 26a is installed and the space in which the first transport screw 26b1 is installed (first transport path B1). A new developing device 26 (including a recycled product) is shipped from a factory with the sheet-like member 26r installed, as shown in FIGS. 4 and 5. That is, at the factory, after the developer G is filled inside the developing device 26 (the first and second transport paths B1 and B2) in a state where assembly into the developing device lower case 26j is completed, the sheet-like member 26r is attached to the base portion 26j1 of the developing device lower case 26j so as to seal the first and second transport paths B1 and B2 to prevent the developer G from leaking. Finally, the developing device upper case 26k is installed so as to cover the developing device lower case 26j in which the sheet-like member 26r has been set, thereby completing the developing device 26 for shipment with the developer G preset therein. 5, one end of the sheet-like member 26r set in the developing device 26 in its longitudinal direction (the direction perpendicular to the plane of FIG. 4, and the left-right direction in FIG. 5) protrudes from the gap between the upper developing case 26k and the lower developing case 26j (where a sealing material (not shown) made of an elastic material and having a slit is installed) to the outside of the developing device 26. When the user grips the protruding portion and pulls it out in the direction of the white arrow in FIG. 5, the opening 26j10 of the base portion 26j1 is opened, and the developing device 26 becomes usable.

[0035] Developing device 26 configured in this manner is mounted to image forming apparatus main body 1 with developer G contained therein and sealed by sheet-like member 26r, as shown in Fig. 4. Such cases include (1) a case where a new developing device 26 is mounted on a new image forming apparatus main body 1 before shipment, and (2) a case where a new (replacement) developing device 26 is mounted on an image forming apparatus main body 1 that has already been used by a user. In either case described above, before the new developing device 26 is used (developing process) in the image forming apparatus 1, the sealed and sealed sheet-like member 26r is pulled out from the developing device 26. Then, the normal image forming process (developing process) is carried out in the state shown in FIG.

[0036] In this manner, in this embodiment, even when the developing device 26 is transported (carried) alone as a replacement, or even when the developing device 26 is transported attached to the image forming device main body 1 at the time of shipment, the developer G previously contained inside the developing device 26 is sealed by the sheet-like member 26r, thereby preventing the developer G contained inside from leaking outside the developing device 26 due to vibrations that occur during transportation, etc.

[0037] In particular, in this embodiment, the sheet-like member 26r is installed inside the developing device 26 so as to separate the developing roller 26a and the first conveying screw 26b1 to form a developer pre-storage section (which is generally a closed space), as shown in Figure 4. This prevents developer G from being carried on the surface of developing roller 26a during transportation, thereby reliably preventing the user from touching the surface of developing roller 26a and becoming soiled with developer G. Furthermore, even when a new developing device 26 is installed in a new image forming apparatus main body 1 and shipped from the factory, it is possible to prevent the surface of the photosensitive drum from being damaged by developer G carried on the surface of developing roller 26a during transportation.

[0038] 4, in the developing device 26 of the present embodiment, when viewed in a cross section perpendicular to the rotation shaft 26a2x of the developing roller 26a (or the rotation shaft 26b11 of the first transport screw 26b1 (developer supply rotor)), the sheet-like member 26r is arranged so as to intersect at 90±10 degrees with an imaginary line S connecting the rotation center of the developing roller 26a and the rotation center of the first transport screw 26b1. In other words, when viewed in a cross section perpendicular to the above-mentioned rotation shaft 26a2x, the sheet-like member 26r is arranged so as to be perpendicular to the imaginary line S. The term "orthogonal" as used above includes not only completely orthogonal but also substantially orthogonal. Furthermore, the term "cross section orthogonal to the rotation shaft" is defined as being synonymous with "cross section orthogonal to the rotation axis or central axis." That is, in the developing device 26 of this embodiment, the sheet-like member 126r is not installed horizontally as in the developing device 126 shown in Figure 6 as a comparative example, but is arranged diagonally so as to be perpendicular to the imaginary line S between the developing roller 26a and the first transport screw 26b1, in accordance with the fact that the first transport screw 26b1 is arranged diagonally downward relative to the developing roller 26a.

[0039] With this configuration, even if the opposing distance between the developing roller 26a and the first transport screw 26b1 (developer supply rotor) is short, the sheet-like member 26r can be provided to separate the developing roller 26a and the first transport screw 26b1. This allows the developing device 26 to be made smaller and lighter, and further allows the amount of developer G for presetting to be reduced. Specifically, to reduce the size and weight of the developing device 26, it is necessary to ensure that even a small amount of developer G in the first transport path B1 is sufficiently scooped up onto the developing roller 26a. To achieve this, the opposing distance between the developing roller 26a and the first transport screw 26b1 must be reduced. However, as in the comparative example of the developing device 126 shown in FIG. 6, if the sheet-like member 126r and the base portion 126j1 of the developing lower case 126j are arranged horizontally without interfering with the first transport screw 26b1, there is a limit to how short the opposing distance between the developing roller 26a and the first transport screw 26b1 can be. As a result, the developing device 26 becomes larger and heavier, and it becomes impossible to reduce the amount of developer G used for presetting. In contrast, in this embodiment, the sheet-like member 26r is arranged so as to be perpendicular to the imaginary line S connecting the rotation center of the developing roller 26a and the rotation center of the first transport screw 26b1, thereby efficiently dividing the space between the developing roller 26a and the first transport screw 26b1. Therefore, the opposing distance between the developing roller 26a and the first transport screw 26b1 can be set short, making it possible to reduce the size and weight of the developing device 26 and further reduce the amount of developer G for presetting.

[0040] Referring now to Figure 4, the developing device 26 in this embodiment is configured so that, when viewed in a cross section perpendicular to the rotational axis direction (rotational axis portions 26a2x, 26b11), the opposing distance between the developing roller 26a and the sheet-like member 26r is longer than the opposing distance between the first conveying screw 26b1 (developer supply rotor) and the sheet-like member 26r. That is, the sheet-like member 26r is not disposed at an intermediate position (equidistant position) between the developing roller 26a and the first transport screw 26b1, but is disposed at a position closer to the first transport screw 26b1. With this configuration, the preset developer G is less likely to be attracted by the magnetic force of the developing roller 26a, and therefore, the sheet-like member 26r is less likely to peel off from the base portion 26j1 due to pressure from the attracted developer G.

[0041] Furthermore, the sheet-like member 26r is removably installed at a position where it will not come into contact with the developing roller 26a even when it is moved toward the developing roller 26a due to the application of an external force (for example, the pressure of the developer G stored in the developer pre-storage section.) In other words, the sheet-like member 26r is positioned at a distance where it will not come into contact with the developing roller 26a even when it is moved toward the developing roller 26a. With this configuration, it is possible to reduce the problem of the developing roller 26a being damaged by contact with the sheet-like member 26r.

[0042] Referring to FIG. 4, in the developing device 26 according to the present embodiment, when viewed in a cross section perpendicular to the rotational axis direction (rotational shaft portions 26a2x, 26b11), both ends of the sheet-like member 26r are removably attached, and a distance X1 from the intersection point where the sheet-like member 26r intersects with the imaginary line S to a downstream sheet-attaching position 26j11 corresponding to the downstream side in the rotational direction of the developing roller 26a is shorter than a distance X2 from the intersection point to an upstream sheet-attaching position 26j12 corresponding to the upstream side in the rotational direction of the developing roller 26a (X1 <X2)。

[0043] More specifically, as described above, the developing lower case 26j (developing case) in this embodiment rotatably holds the developing roller 26a and the first conveying screw 26b1 (developer supply rotor), and is formed with a base 26j1 to which a sheet-like member 26r is removably attached and which has an opening 26j10 (see FIG. 5) sealed by the sheet-like member 26r. A downstream sheet attachment position 26j11 and an upstream sheet attachment position 26j12 are formed on the base 26j1. 4, the developing device 26 in this embodiment is configured such that, when viewed in a cross section perpendicular to the rotational axis direction (rotational shaft portions 26a2x, 26b11), a distance X1 from the intersection point where the sheet-like member 26r intersects with the imaginary line S to a downstream sheet sticking position 26j11 (a position on the base portion 26j1 corresponding to the downstream side in the rotational direction of the developing roller 26a, and the sticking portion on the right side in FIG. 4) is shorter than a distance X2 from the intersection point to an upstream sheet sticking position 26j12 (a position on the base portion 26j1 corresponding to the upstream side in the rotational direction of the developing roller 26a, and the sticking portion on the left side in FIG. 4) (X1 <X2)。 This is because, when the upstream sheet attachment position 26j12 is close to the developing roller 26a, the movement of the developer G, which is released from the developing roller 26a at the position of the developer release magnetic pole H4 toward the first transport path B1 during the development process, is likely to be hindered by the upstream sheet attachment position 26j12. If this deterioration in developer release of the developer G occurs, abnormal images will be produced. In this embodiment, the upstream sheet attachment position 26j12 is located at a position sufficiently distant from the developing roller 26a, so that such a problem is unlikely to occur.

[0044] As shown in FIG. 4, in this embodiment, the doctor blade 26c (developer regulating member) is disposed below the developing roller 26a, which is disposed obliquely above the first transport screw 26b1. The base portion 26j1 is formed so that the downstream sheet attachment position 26j11 is located at a position lower than the top Z of the first conveying screw 26b1 (developer supply rotor), and the upstream sheet attachment position 26j12 is located at a position higher than the top Z. This configuration makes it easier to arrange the sheet member 26r so that it is perpendicular to the imaginary line S that connects the rotation center of the developing roller 26a and the rotation center of the first conveying screw 26b1.

[0045] Also, as shown in Figure 4, in this embodiment, the doctor blade 26c (developer regulating member) is set so that the position of its tip (upper end) facing the developing roller 26a is higher than the downstream sheet attachment position 26j11 and lower than the upstream sheet attachment position 26j12. With this configuration, it is easy to arrange the sheet member 26r so that it is perpendicular to the imaginary line S connecting the rotation center of the developing roller 26a and the rotation center of the first conveying screw 26b1, while maintaining the function of the doctor blade 26c well.

[0046] Also, as shown in FIG. 5, in the developing device 26 of this embodiment, the widthwise range X4 of the sheet-like member 26r is set so as to be within the widthwise range X3 of the base portion 26j1 and include the widthwise range X5 of the opening 26j10. In other words, when the width of the short side at the outer periphery of the base portion 26j1 is X3, the width of the short side of the opening 26j10 is X5, and the width of the short side of the sheet-like member 26r is X4, the relationship X3>X4>X5 holds. With this configuration, the opening 26j10 is reliably sealed by the sheet-like member 26r, and the sheet-like member 26r can be easily pulled out in the direction of the white arrow when the developing device 26 is first used.

[0047] <Variation 1> 7, the developing device 26 in Modification 1 includes a first gear 91 mounted on a rotation shaft 26a2x (see FIG. 3) of the developing roller 26a, a second gear 92 mounted on a rotation shaft 26b11 (see FIG. 3) of the first transport screw 26b1 (developer supply rotor), a third gear 93 mounted on a rotation shaft 26b21 (see FIG. 3) of the second transport screw 26b2, and an idler gear 94 meshing with the first gear 91, the second gear 92, and the third gear 93, respectively, which are provided at one longitudinal end (drive side) of the developing device 26. A driving force is transmitted from a drive motor (not shown) to any of the first to third gears 91 to 93 and the idler gear 94, causing the developing roller 26a and the first and second transport screws 26b1 and 26b2 to rotate in respective predetermined directions. As shown in Figure 7, when viewed in a cross section perpendicular to the rotational axis direction (rotational shaft portions 26a2x, 26b11), the developing device 26 in variant example 1 has at least a portion of the sheet-like member 26r arranged in the space surrounded by the first gear 91, the second gear 92, and the idler gear 94. By configuring it in this manner, even if the sheet-like member 26r is configured to be pulled out from one longitudinal end side (drive side) of the developing device 26, problems such as the sheet-like member 26r interfering with the first gear 91, the second gear 92, or the idler gear 94 are less likely to occur. In particular, in variant example 1, the outer diameter (tooth tip circle diameter) of the idler gear 94 is configured to be smaller than the outer diameter (tooth tip circle diameter) of the first gear 91 and smaller than the outer diameter (tooth tip circle diameter) of the second gear 92.Therefore, in the space surrounded by the first gear 91, the second gear 92, and the idler gear 94, the width of the sheet-like member 26r in the short direction can be secured relatively wide, and it is also easier to secure the opening width in the short direction of the opening 26j10 in the base portion 26j1.

[0048] <Variation 2> As shown in Figure 8, in the developing device 26 of variant example 2, the base portion 26j1 has a cutout portion 26j15 (or recess) formed at the longitudinal end (the portion where the end seal of the developing roller 26a is installed) that reduces the portion that overlaps with the developing upper case 26k. If the developing device 26 is placed vertically by itself during transportation or storage, the developer G will be packed unevenly at the longitudinal end portion that is located at the bottom. In such a case, if a large area of the sheet-like member 26r is sandwiched between the base portion 26j1 and the developing upper case 26k, the developer G that has entered between the base portion 26j1 and the sheet-like member 26r will push the sheet-like member 26r into the developing upper case 26k, making it difficult to pull out the sheet-like member 26r when the device arrives. In contrast, in the second modification, a notch 26j15 is provided in the overlapping portion of the base portion 26j1 and the upper developing case 26k, reducing the area where the sheet-like member 26r is sandwiched in that portion, making such a problem less likely to occur.

[0049] <Variation 3> As shown in FIG. 9, in the developing device 26 of the third modified example, the opening 26j10 in the base portion 26j1 is formed so that the opening area W perpendicular to the imaginary line S gradually decreases from above to below. In particular, in the base portion 26j1 in Modification 3, the inner wall surface of the opening 26j10 on the upstream sheet sticking position 26J12 side is formed so as not to enter the first conveyance path B1, just like the inner wall surface of the opening 26j10 on the downstream sheet sticking position 26j11 side. That is, when viewed in a cross section perpendicular to the rotation axis direction (rotation axis portions 26a2x, 26b11), the inner wall surface of the opening 26j10 is formed in a substantially V-shape with the imaginary line S as the base. By configuring the developing device in this way, even if the developing device 26 is transported in a state where it is turned upside down from the normal position, when the developing device 26 is returned to the normal position before use, the aggregated preset developer G is likely to break down. Furthermore, in the developing step, the supply of developer from the first conveying screw 26b1 to the developing roller 26a is less likely to be hindered by the downstream sheet sticking position 26j11.

[0050] <Variation 4> As shown in FIG. 10, the developing device 26 in the fourth modified example also has a base portion 26j1 formed on the developing lower case 26j. Here, in the developing device 26 in variant example 4, the base portion 26j1 is not integrally formed as part of the developing lower case 26j, but is attached (glued) to the developing lower case 26j as a separate part via double-sided tape, adhesive, etc. An opening 26j10 is formed in the base 26j, and a sheet-like member 26r is placed on the base 26j so as to cover the opening 26j10. When the developing device 26 starts to be used, the sheet-like member 26r is pulled out from the base 26j1. The base 26j1 continues to function as a part of the developing lower case 26j even after the developing device 26 starts to be used. By configuring the base portion 26j to be installed as a separate part on the lower developing case 26j in this way, it becomes possible to form the base portion 26j1 from a material to which the sealing member 26r can be easily heat-sealed or attached with double-sided tape, for example, when the lower developing case 26j is formed from a material to which the sealing member 26r is difficult to heat-seal or attach with double-sided tape.

[0051] As described above, developing device 26 in this embodiment is a developing device that is detachably installed in image forming apparatus main body 1 and contains developer G, and is provided with developing roller 26a that carries developer G and develops a latent image formed on the surface of photosensitive drum 21 (image carrier), and first transport screw 26b1 (developer supply rotor) that rotates in a predetermined direction opposite developing roller 26a to supply developer G to developing roller 26a. In addition, to prevent developer G contained in developing device 26 from leaking to the outside, a removable sheet-like member 26r is provided that separates developing roller 26a and first transport screw 26b1 and forms a developer pre-container in which developer G is contained inside developing device 26 on the side of first transport screw 26b1. When viewed in a cross section perpendicular to the rotational axis of the developing roller 26a or the first conveying screw 26b1, the sheet-like member 26r is positioned so that it intersects at 90±10 degrees with the imaginary line S connecting the rotational center of the developing roller 26a and the rotational center of the first conveying screw 26b1. This allows the sheet-like member 26r to be provided so as to separate the developing roller 26a and the first transport screw 26b1 even if the opposing distance between the developing roller 26a and the first transport screw 26b1 is short.

[0052] In the present embodiment, the developing device 26 is not a component of the process cartridge 20, but is a unit that can be attached to and detached from the image forming apparatus main body 1 independently. However, the developing device 26 can also be one of the components of the process cartridge 20, and configured to be attached and detached from the image forming apparatus main body 1 as a process cartridge. In such a case, the same effect as that of this embodiment can be obtained. In this application, a "process cartridge" is defined as a unit that integrates at least one of a charging device that charges an image carrier, a developing device that develops a latent image formed on the image carrier, and a cleaning device that cleans the image carrier, with an image carrier, and is configured to be detachable from the image forming apparatus main body.

[0053] In this embodiment, the present invention is applied to a developing device 26 in which two transport screws 26b1 and 26b2 (transport members) are arranged side by side in the horizontal direction and a doctor blade 26c is arranged below a developing roller 26a. However, the configuration of the developing device to which the present invention is applied is not limited to this, and the present invention can also be applied to, for example, a developing device in which three or more transport members are arranged side by side in the horizontal direction, a developing device in which multiple transport members are arranged side by side in the vertical direction, or a developing device in which a doctor blade is arranged above a developing roller. In this embodiment, the present invention is applied to the developing device 26 in which a transport screw (first transport screw 26b1) having a screw portion 26b12 wound around a rotation shaft portion 26b11 is installed as the developer supply rotor. However, the developer supply rotor is not limited to this, and the present invention can also be applied to, for example, a developing device in which a transport paddle having a plurality of blade portions formed radially in the circumferential direction on a rotation shaft portion is installed as the developer supply rotor. In such cases, the same effect as that of this embodiment can be obtained.

[0054] It is clear that the present invention is not limited to the present embodiment, and that within the scope of the technical concept of the present invention, each embodiment may be appropriately modified in addition to what is suggested in each embodiment. Furthermore, the number, position, shape, etc. of the components are not limited to the present embodiment, and the number, position, shape, etc. of the components may be any number, position, shape, etc. that is suitable for implementing the present invention. [Explanation of symbols]

[0055] 1 Image forming apparatus (image forming apparatus main body), 20, 20Y, 20M, 20C, 20BK process cartridges, 21 photosensitive drum (image carrier), 26 developing device, 26a developing roller (developer carrier), 26a2x Rotating shaft, 26b1 first conveying screw (developer supply rotor), 26b11 Rotating shaft part, 26b12 screw section, 26b2 second conveying screw, 26c Doctor blade (developer control member), 26j developing case (developing case), 26j1 base part, 26j10 aperture, 26j11 Downstream sheet attachment position (downstream sheet attachment part), 26j12 Upstream sheet attachment position (upstream sheet attachment part), 26j15 Notch, 26k developing case (developing case), 26r Sheet-shaped member (sealing member), 91 1st gear, 92 2nd gear, 94 idler gear, B1 First transport route (transport route), B2 Second transport route, S virtual line, Z top, G Developer (two-component developer).

[0056] The present invention can also be embodied in a combination of Supplementary Notes 1 to 12, as follows. (Appendix 1) A developing device that is detachably installed in the image forming apparatus main body and contains a developer therein, a developing roller that carries a developer and develops a latent image formed on the surface of the image carrier; a developer supplying rotor that faces the developing roller and rotates in a predetermined direction to supply developer to the developing roller; a removable sheet-like member that separates the developing roller from the developer supply rotor so as to prevent the developer contained in the developing device from leaking to the outside, and forms a developer pre-container section in which the developer is contained inside the developing device on the developer supply rotor side; Equipped with A developing device characterized in that, when viewed in a cross section perpendicular to the rotational axis of the developing roller or the developer supply rotor, the sheet-like member is arranged so as to intersect at 90±10 degrees with respect to an imaginary line connecting the rotational center of the developing roller and the rotational center of the developer supply rotor. (Appendix 2) The developing device described in Appendix 1, characterized in that, when viewed in cross section, the opposing distance between the developing roller and the sheet-like member is longer than the opposing distance between the developer supply rotor and the sheet-like member. (Appendix 3) The developing device according to claim 1 or 2, characterized in that, when viewed in cross section, both ends of the sheet-like member are removably attached, and the distance from the intersection point where the sheet-like member intersects with the virtual line to a downstream sheet attachment position corresponding to the downstream side in the rotation direction of the developing roller is shorter than the distance from the intersection point to an upstream sheet attachment position corresponding to the upstream side in the rotation direction of the developing roller. (Appendix 4) a developing case having a base portion to which the sheet-like member is removably attached and having an opening sealed by the sheet-like member, the developing case rotatably holding the developing roller and the developer supplying rotor, 4. The developing device according to claim 3, wherein the downstream sheet sticking position and the upstream sheet sticking position are formed on the base portion. (Appendix 5) The developing device described in Appendix 4, wherein the widthwise range of the sheet-like member is set within the widthwise range of the base portion and includes the widthwise range of the opening. (Appendix 6) the developing case includes a lower developing case in which the base portion is formed, and an upper developing case disposed above the lower developing case, The developing device according to claim 4 or 5, wherein the base portion has a notch or recess formed at a longitudinal end portion thereof to reduce the portion that overlaps with the upper developing case. (Appendix 7) The developing device described in any one of Appendix 4 to Appendix 6, characterized in that the base portion is formed so that the downstream sheet attachment position is located at a position lower than the top of the developer supply rotating body, and the upstream sheet attachment position is located at a position higher than the top. (Appendix 8) 8. The developing device according to any one of claims 4 to 7, wherein the opening is formed so that the area of the opening perpendicular to the imaginary line gradually decreases from top to bottom. (Appendix 9) a developer regulating member disposed below the developing roller disposed obliquely above the developer supply rotary body and opposing the developing roller to regulate the amount of developer carried on the surface of the developing roller; A developing device described in any one of Appendix 3 to Appendix 8, characterized in that the position of the tip end of the developer regulating member facing the developing roller is higher than the downstream sheet attachment position and lower than the upstream sheet attachment position. (Appendix 10) A developing device described in any one of Appendix 1 to Appendix 9, characterized in that the sheet-like member is removably installed in a position where it will not come into contact with the developing roller even if an external force is applied and it is pushed toward the developing roller. (Appendix 11) a first gear provided on a rotation shaft portion of the developing roller, a second gear provided on a rotation shaft portion of the developer supply rotor, and idler gears meshing with the first gear and the second gear, A developing device as described in any one of Appendix 1 to Appendix 10, characterized in that, when viewed in cross section, at least a portion of the sheet-like member is arranged in a space surrounded by the first gear, the second gear, and the idler gear. (Appendix 12) 12. The developing device according to claim 11, wherein the idler gear has an outer diameter smaller than that of the first gear and smaller than that of the second gear. (Appendix 13) The developer supply rotor is a first transport screw having a screw portion wound around a rotation shaft portion and capable of transporting the developer in the rotation shaft direction, The developing device according to any one of appendixes 1 to 12, further comprising a second transport screw that faces the first transport screw via a wall portion and forms a circulation path for the developer together with the first transport screw. (Appendix 14) a process cartridge detachably installed in the image forming apparatus main body, A process cartridge comprising the developing device according to any one of claims 1 to 13 and the image carrier, the process cartridge being integrally provided with the developing device. (Appendix 15) An image forming apparatus comprising the developing device according to any one of Supplementary Notes 1 to 13. [Prior art documents] [Patent documents]

[0057] [Patent Document 1] Patent No. 4332472

Claims

1. A developing device that is detachably installed in the image forming apparatus main body and contains a developer therein, a developing roller that carries a developer and develops a latent image formed on the surface of the image carrier; a developer supplying rotor that faces the developing roller and rotates in a predetermined direction to supply developer to the developing roller; a removable sheet-like member that separates the developing roller from the developer supply rotor so as to prevent the developer contained in the developing device from leaking to the outside, and forms a developer pre-container section in which the developer is contained inside the developing device on the developer supply rotor side; Equipped with A developing device characterized in that, when viewed in a cross section perpendicular to the rotational axis of the developing roller or the developer supply rotor, the sheet-like member is arranged so that it intersects at 90±10 degrees with respect to an imaginary line connecting the center of rotation of the developing roller and the center of rotation of the developer supply rotor.

2. 2. The developing device according to claim 1, wherein, when viewed in cross section, the opposing distance between the developing roller and the sheet-like member is longer than the opposing distance between the developer supply rotary member and the sheet-like member.

3. A developing device as described in claim 1 or claim 2, characterized in that, when viewed in cross section, both ends of the sheet-like member are removably attached, and the distance from the intersection point where the sheet-like member intersects with the virtual line to a downstream sheet attachment position corresponding to the downstream side in the rotation direction of the developing roller is shorter than the distance from the intersection point to an upstream sheet attachment position corresponding to the upstream side in the rotation direction of the developing roller.

4. a developing case having a base portion to which the sheet-like member is removably attached and having an opening sealed by the sheet-like member, the developing case rotatably holding the developing roller and the developer supplying rotor, 4. The developing device according to claim 3, wherein the downstream sheet adhering position and the upstream sheet adhering position are formed on the base portion.

5. 5. The developing device according to claim 4, wherein the width of the sheet-like member is set so as to be within the width of the base portion and to include the width of the opening.

6. the developing case includes a lower developing case in which the base portion is formed, and an upper developing case disposed above the lower developing case, 5. The developing device according to claim 4, wherein the base portion has a notch or a recess formed at a longitudinal end portion thereof to reduce the portion that overlaps with the upper developing case.

7. 5. The developing device according to claim 4, wherein the base portion is formed so that the downstream sheet attachment position is located at a position lower than the top of the developer supply rotating body, and the upstream sheet attachment position is located at a position higher than the top.

8. 5. The developing device according to claim 4, wherein the opening is formed so that the area of the opening perpendicular to the imaginary line gradually decreases from top to bottom.

9. a developer regulating member disposed below the developing roller disposed obliquely above the developer supply rotary body and opposing the developing roller to regulate the amount of developer carried on the surface of the developing roller; 4. The developing device according to claim 3, wherein the position of the leading end of the developer regulating member facing the developing roller is higher than the downstream sheet adhering position and lower than the upstream sheet adhering position.

10. 3. The developing device according to claim 1, wherein the sheet-like member is detachably installed at a position where it does not come into contact with the developing roller even when an external force is applied and the sheet-like member is moved toward the developing roller.

11. a first gear provided on a rotation shaft portion of the developing roller, a second gear provided on a rotation shaft portion of the developer supply rotor, and idler gears meshing with the first gear and the second gear, 3. The developing device according to claim 1, wherein at least a portion of the sheet-like member is disposed in a space surrounded by the first gear, the second gear, and the idler gear when viewed in cross section.

12. 12. The developing device according to claim 11, wherein the outer diameter of the idler gear is smaller than the outer diameter of the first gear and smaller than the outer diameter of the second gear.

13. the developer supply rotor is a first transport screw having a screw portion wound around a rotation shaft portion and capable of transporting the developer in the rotation shaft direction, 3. The developing device according to claim 1, further comprising a second transport screw that faces the first transport screw via a wall portion and forms a circulation path for the developer together with the first transport screw.

14. a process cartridge detachably installed in the image forming apparatus main body, 3. A process cartridge comprising the developing device according to claim 1 or 2 and the image carrier, the developing device and the image carrier being integrally provided.

15. 3. An image forming apparatus comprising the developing device according to claim 1.

Images