Image forming device

Abstract

To solve the problem in which mixing of deteriorated toner and new toner may form a portion with high image density and a portion with low image density on a recording material.SOLUTION: A developing device has: a developing roller, a supply roller that supplies a developer to the developing roller; an attachment part to which a replenishment container is removably attached; and a frame body. The frame body has: a storage chamber that stores the developer replenished from the replenishment container; a developing chamber in which the developing roller and the supply roller are arranged; and a wall part that partitions the developing chamber and the storage chamber from each other so that an opening communicating the developing chamber and the storage chamber with each other is formed, wherein the developing roller is movable to a first position where the developing roller develops an electrostatic latent image, and a second position. When the replenishment container is attached to the attachment part, the frame body is located at the second position. For the vertical direction, a height from the lowermost part of the supply roller to an upper end of the wall part is larger when the frame body is at the second position than that when the frame body is at the first position.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an image forming apparatus that uses an electrophotographic recording method, such as a laser printer, a copying machine, or a facsimile, and a developing device used therein. [Background technology]

[0002] In an image forming apparatus that forms an image on a recording material using an electrophotographic image forming method (electrophotographic process), an electrostatic image is formed on an electrophotographic photosensitive member as an image carrier in the image forming process, and the electrostatic image is developed with toner.

[0003] One example of an image forming apparatus is a toner supply system. Patent Document 1 discloses an image forming apparatus equipped with a developing device that includes a developing roller, a supply roller, and a developing blade. Patent Document 1 also discloses a toner supply container that contains toner and is detachable from the developing device. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2020-154299 Summary of the Invention [Problem to be solved by the invention]

[0005] The toner carried on the developing roller is rubbed against the developing blade and the supply roller. This rubbing causes external additives added to the toner to become detached or embedded, causing the toner to deteriorate. As the toner deteriorates, it becomes difficult for the toner to be charged, and the amount of charge on the toner decreases.

[0006] When a replenishment method using a replenishment container is adopted, the toner in the developing device deteriorates and becomes difficult to charge, while new toner replenished from the replenishment container is not deteriorated and is easier to charge than deteriorated toner. When deteriorated toner and new toner are mixed, areas of high and low image density may be formed on the recording material. Specifically, when a halftone image is printed after printing a solid image, areas of high and low image density may be formed on the halftone image, resulting in a so-called ghost image.

[0007] An object of the present invention is to suppress the occurrence of ghost images due to toner replenishment. [Means for solving the problem]

[0008] One of the inventions of the present application is as follows.

[0009] A developing device to which a supply container is removably attached, a developing roller for developing the electrostatic latent image formed on the image carrier; a supply roller that contacts the developing roller and supplies developer to the developing roller; a mounting portion to which the supply container is removably attached; a frame having a storage chamber configured to store the developer replenished from the supply container, a developing chamber in which the developing roller and a supply roller are disposed, and a wall portion extending in a direction intersecting a horizontal direction and separating the developing chamber from the storage chamber so as to form an opening communicating the developing chamber with the storage chamber, the frame being configured to be movable between a first position where the developing roller develops the electrostatic latent image and a second position retracted from the first position; a developing device having a moving member that moves the frame from the first position to the second position; a cover member configured to be movable between a cover position that covers the mounting portion and an exposed position that exposes the mounting portion; and In the vertical direction, the wall portion is located below the opening, and the upper end of the wall portion is located above the lowermost part of the supply roller, When the supply container is attached to the attachment portion, the frame is located at the second position, the wall portion is disposed such that a height from the lowermost portion of the supply roller to the upper end of the wall portion in the vertical direction is higher when the frame body is in the second position than when the frame body is in the first position; an image forming apparatus, characterized in that the moving member moves the frame from the first position to the second position in conjunction with the movement of the cover member from the cover position toward the exposed position; [Effects of the Invention]

[0010] As described above, according to the present invention, it is possible to suppress the occurrence of ghost images due to toner replenishment. [Brief explanation of the drawings]

[0011] [Figure 1]FIG. 2 is a schematic cross-sectional view of the developing device according to the first embodiment. [Figure 2] FIG. 1 is a perspective view of an image forming apparatus. [Figure 3] FIG. 2 is a schematic cross-sectional view of a process unit. [Figure 4] FIG. 2 is a diagram illustrating the internal configuration of the image forming apparatus. [Figure 5] FIG. 2 is a side view of the image forming apparatus for explaining the arrangement of a supply unit. [Figure 6] FIG. [Figure 7] FIG. 1 is a perspective view of an image forming apparatus. [Figure 8] FIG. [Figure 9] FIG. 10 is an explanatory diagram of an image pattern for evaluating the level of a ghost image. [Figure 10] FIG. 1 is a schematic diagram of a developing device according to Comparative Example 1. [Figure 11] FIG. 10 is a schematic configuration diagram of a developing device according to Comparative Example 2. [Figure 12] FIG. 10 is a schematic diagram of a developing device according to a modified example. [Figure 13] 10 is a graph showing the toner charge amount in Experiment 2. DETAILED DESCRIPTION OF THE INVENTION

[0012] The following describes in detail exemplary embodiments of the present invention with reference to the drawings. However, the dimensions, materials, shapes, and relative positions of the components described in the embodiments may be changed as appropriate depending on the configuration of the device to which the invention is applied and various conditions. In other words, the scope of the present invention is not intended to be limited to the following embodiments. Furthermore, in the drawings used in the following description, for the purpose of explanation, some components or parts of the components may be omitted or simplified.

[0013] [Example 1] <Overall structure> The overall configuration of an image forming apparatus 1 in this embodiment will be described. The image forming apparatus 1 in this embodiment is a monochrome laser beam printer that uses an electrophotographic process. The image forming apparatus 1 is capable of performing an image forming operation that forms an image using a developer (toner) on a recording material P in accordance with image information transmitted from an external device such as a personal computer. Examples of the recording material P include recording paper, label paper, overhead projector sheets, and cloth.

[0014] In the following description, the height direction of the image forming apparatus 1 (the direction opposite to the direction of gravity) when the image forming apparatus 1 is installed on a horizontal surface is referred to as the Z direction. The direction that intersects the Z direction and is parallel to the direction of the rotation axis of the photosensitive drum 11 (main scanning direction) described later is referred to as the X direction. The direction that intersects the X direction and the Z direction is referred to as the Y direction. The X, Y, and Z directions preferably intersect perpendicularly to each other. For convenience, the positive side of the X direction is referred to as the right side and the negative side is referred to as the left side; the positive side of the Y direction is referred to as the front side or front side and the negative side is referred to as the rear side or back side; and the positive side of the Z direction is referred to as the upper side and the negative side is referred to as the lower side. In this embodiment, the Z direction is parallel to the vertical direction, and the X and Y directions are parallel to the horizontal direction.

[0015] 2 is a perspective view of the image forming apparatus 1. The image forming apparatus 1 has a feed tray 4 that stores recording materials P, and a discharge tray (opening / closing member, cover member) 14 that stacks discharged recording materials P. The feed tray 4 can be pulled out in the Y direction, allowing the user to replenish recording materials P.

[0016] The recording material P, which has been fed from the feed tray 4 and on which an image has been formed, is discharged from the discharge port 15 in the discharge direction shown in Fig. 2 and is stacked on the discharge tray 14. In this embodiment, the discharge direction is parallel to the Y direction.

[0017] A front cover 70 is provided on a portion of the end face (part of the front face) of the image forming apparatus 1 downstream in the discharge direction, covering a circuit board 100 (described later). An exterior cover 71 is provided on a portion of the front face other than the portion where the front cover 70 is provided, as well as on the side and top faces of the image forming apparatus 1. The front cover 70, the exterior cover 71, and the discharge tray 14 described above together form a housing 72 of the image forming apparatus 1. Here, the housing 72 is a member that covers the entire image forming apparatus 1, and houses process components such as a scanner unit 50 and an image forming section 500 (described later) inside. The discharge port 15 described above is an opening formed in a portion of the housing 72, and the recording material P is discharged to the outside of the image forming apparatus 1 through this opening. The recording material P discharged from the discharge port 15 is stacked on an upper surface (stacking section) provided on the discharge tray 14.

[0018] <Process unit configuration> Next, the overall configuration of the process unit 500 housed in the housing 72 of the image forming apparatus 1 will be described.

[0019] 3 is a schematic cross-sectional (main cross-sectional) view of the process unit 500 as viewed along the longitudinal direction (direction of the rotation axis) of the photosensitive drum 1. The orientation of the process unit 500 in FIG. 3 represents the orientation of the process unit 500 when positioned inside the image forming apparatus 1 folded horizontally. In the following description, descriptions of the positional relationships and directions of the components of the process unit 500 refer to the positional relationships and directions in the orientation shown in FIG. 3. In other words, the up-down direction in FIG. 3 corresponds to the vertical direction, and the left-right direction corresponds to the horizontal direction.

[0020] The process unit 500 is configured by integrating a photosensitive unit 300 including a photosensitive drum 11 as an image carrier and a developing device (developing unit) 230 including a developing roller 12 as a developer carrier.

[0021] The developing device 230 is coupled to the photosensitive unit 300 via a rotation axis Q. The developing device 230 is movable relative to the photosensitive unit 300. More specifically, the developing device 230 is rotatable around the rotation axis Q relative to the photosensitive unit 300.

[0022] The photosensitive drum 11 is a cylindrically shaped photosensitive member. The photosensitive drum 11 of this embodiment has a photosensitive layer formed of a negatively chargeable organic photosensitive member on a drum-shaped substrate made of aluminum. The photosensitive drum 11 is rotated by a motor in a predetermined direction (clockwise in the drawing) at a predetermined process speed.

[0023] The charging roller 17 contacts the photosensitive drum 11 with a predetermined pressure to form a charging portion. A desired charging voltage is applied to the charging roller 17 by a charging high-voltage power supply, thereby uniformly charging the surface of the photosensitive drum 11 to a predetermined potential. In this embodiment, the photosensitive drum 11 is negatively charged by the charging roller 17.

[0024] The charged surface of the photosensitive drum 11 is exposed by a scanner unit 50 serving as an exposure means, which will be described later. The scanner unit 50 scans and exposes the surface of the photosensitive drum 11 by irradiating the photosensitive drum 11 with laser light corresponding to input image information. This exposure forms an electrostatic latent image corresponding to the image information on the surface of the photosensitive drum 11. Note that the exposure means is not limited to a laser scanner device, and for example, an LED exposure device in which a plurality of LEDs (light emitting diodes) are arranged along the longitudinal direction of the photosensitive drum 11 may also be used.

[0025] The developing device 230 has a developing roller 12 that develops the electrostatic latent image formed on the photosensitive drum 11 with toner, and a supply roller (supply member, toner supply roller) 20 that contacts the developing roller 12 and supplies toner to the developing roller 12. The developing device 230 has a conveying member 22 as an agitating member that agitates the toner inside a toner storage chamber 230a. The developing roller 12, the supply roller 20, and the conveying member 22 rotate when a driving force is transmitted from a motor of the image forming apparatus 1.

[0026] The developing device 230 has a developing frame (frame) 30. The developing frame 30 is provided with a toner storage chamber (developer storage chamber, storage chamber) 230a configured to store toner supplied from a supply pack 210 (described later), and a developing chamber 230b in which the developing roller 12 and the supply roller 20 are arranged.

[0027] The developing frame 30 has wall portions 30a and 30b that separate the toner storage chamber 230a and the developing chamber 230b. The toner storage chamber 230a and the developing chamber 230b communicate with each other via an opening (opening) 30c between the wall portions 30a and 30b. In other words, the wall portions 30a and 30b separate the toner storage chamber 230a and the developing chamber 230b so as to form the opening 30c that connects the toner storage chamber 230a and the developing chamber 230b. In the vertical direction, the wall portion 30a is located above the opening 30c, and the wall portion 30b is located below the opening 30c.

[0028] The transport member 22 has an elastic transport body and is housed in the toner storage chamber 230a. The transport member 22 is rotatably supported by the developing frame 30, and transports toner from the toner storage chamber 230a to the developing chamber 230b through the opening 30c as it rotates. Note that the transport member 22 is not limited to a rotating type. For example, it may be a swinging type.

[0029] The toner storage chamber 230a is formed with a receiving portion 230c configured to be able to receive toner supplied from the supply pack 210. The receiving portion 230c is in communication with a supply path 203, which will be described later.

[0030] In the toner storage chamber 230a, the toner may be stirred up by the conveying member 22, or may be statically accumulated. When the toner is statically accumulated, the toner is mainly present in the lower region of the toner storage chamber 230a. In this embodiment, the lowermost part of the toner storage chamber 230a in the vertical direction (the direction of gravity) is located below the upper end of the wall portion 30b.

[0031] The developing frame 30 is movable between a development position (contact position, first position) where the developing roller 12 develops the electrostatic latent image formed on the photosensitive drum 11, and a retracted position (separated position, second position, first retracted position) retracted from the development position.

[0032] In this embodiment, when the developing frame 30 is in the developing position, the developing roller 12 abuts against the photosensitive drum 11. When the developing frame 30 is in the retracted position, the developing roller 12 is separated from the photosensitive drum 11. The developing frame 30 is rotatable about a rotation axis Q relative to the photosensitive drum 11, and is movable between the developing position and the retracted position.

[0033] The movement of the developing frame 30 is synonymous with the movement of the developing device 230. Therefore, in the following description, the developing position of the developing frame 30 can be referred to as the developing position of the developing device 230. The retracted position of the developing frame 30 can be referred to as the retracted position of the developing device 230.

[0034] The developing roller 12 is disposed at the opening of the developing chamber 230b so as to face the photosensitive drum 11. The supply roller 20 is in contact with the developing roller 12. As the supply roller 20 rotates, toner is applied to the surface of the developing roller 20.

[0035] The developing device 230 has a developing blade 32 as a regulating member. The developing blade 32 has an elastic member that contacts the developing roller 12 in a bent state.

[0036] The electrostatic latent image is developed by applying a predetermined developing voltage to the developing roller 12. A DC high voltage power supply was used as the output source of the developing voltage.

[0037] The developing roller 12 rotates in the direction of arrow D (counterclockwise) and the supply roller 20 rotates in the direction of arrow E (counterclockwise). The supply roller 20 is an elastic sponge roller with a foam layer formed on the outer periphery of a conductive core. The supply roller 20 and the developing roller 12 are in contact with each other and rotate in opposite directions at a nip (contact area). This operation removes toner from the developing roller 12 and supplies toner from the supply roller 20 to the developing roller 12.

[0038] The developing device 230 of this embodiment uses a contact development method. That is, a toner layer carried on the developing roller 12 comes into contact with the photosensitive drum 11 in a development section (development area) where the photosensitive drum 11 and the developing roller 12 face each other. A development voltage is applied to the developing roller 12 by a development power supply. Under the development voltage, the toner carried on the developing roller 12 is transferred from the developing roller 31 to the drum surface in accordance with the potential distribution on the surface of the photosensitive drum 11, thereby developing the electrostatic latent image into a toner image. Note that this embodiment employs a reversal development method. That is, the surface of the photosensitive drum 11 is charged and then exposed to light, causing the amount of charge to decay. A toner image is formed by toner adhering to the area where the amount of charge has decayed.

[0039] <Toner> In this embodiment, a toner having a particle size of 6 μm and a normal negative charge polarity is used. As an example of the toner used in this embodiment, a polymerized toner produced by a polymerization method is used. The toner used in this embodiment is a so-called non-magnetic one-component developer that does not contain a magnetic component. A non-magnetic one-component developer is carried on the developing roller 12 mainly by intermolecular forces and electrostatic forces (image forces). In addition to toner particles, a one-component developer may also contain additives (e.g., wax or silica particles) to adjust the fluidity and charging performance of the toner. These additives are sometimes called external additives.

[0040] The toner carried on the developing roller 12 is rubbed against the developing blade 32 and the supply roller 20. This rubbing causes additives to be liberated from the surface of the toner particles or embedded in the toner particles, causing the toner particles to aggregate together (toner deterioration). Regarding the toner cohesion, which will be described later, toner with a high cohesion is generally less likely to be charged than toner with a low cohesion.

[0041] During image formation, the wall portion 30b has the function of receiving the toner that has passed through the opening 30c and spilled from the developing roller 12 or the supply roller 20. Furthermore, the height of the wall portion 30b is preferably set to a height that allows the toner to easily circulate (not easily accumulate) from the toner storage chamber 230a to the developing chamber 230b and from the developing chamber 230b to the toner storage chamber 230a, in order to reduce the chances of the same toner being rubbed against each other and suppress toner deterioration.

[0042] In this embodiment, toner with a cohesion of 30 to 40% in its initial state (new state) is used. To ensure the fluidity of the toner throughout the use period of the process unit 500, it is desirable to use toner with such a cohesion.

[0043] The degree of cohesion of the toner of this embodiment was measured as follows.

[0044] First, a powder tester (manufactured by Hosokawa Micron Co., Ltd.) equipped with a digital vibration meter (DIGITAL VIBLATION METER MODEL 1332 manufactured by SHOWA SOKKI CORPORATION) was used as the measuring device.

[0045] The measurement method involved placing 390-mesh, 200-mesh, and 100-mesh sieves on a vibration table in order of narrowest mesh size. That is, the sieves were stacked in the order 390 mesh, 200 mesh, and 100 mesh, with the 100-mesh sieve at the top. Five grams of accurately weighed sample (toner) was placed on top of the 100-mesh sieve, and the digital vibrometer was adjusted to read a displacement of 0.60 mm (peak-to-peak), followed by vibration for five seconds. The mass of the sample remaining on each sieve was then measured, and the degree of cohesion was calculated using the following formula: Cohesion (%) = (mass of sample remaining on 100-mesh sieve / 5 g) x 100 + (mass of sample remaining on 200-mesh sieve / 5 g) x 60 + (mass of sample remaining on 390-mesh sieve / 5 g) x 20 <Image formation operation> The flow of the image forming operation on the recording material P will be described with reference to Fig. 4. Fig. 4 is a diagram illustrating the internal configuration of the image forming apparatus 1 as viewed from the X direction (the direction of the rotation axis of the photosensitive drum 11).

[0046] The image forming apparatus 1 has a control unit (CPU, arithmetic unit) 199. The control unit 199 controls the operation of the image forming apparatus 1 to perform an image forming operation on a recording material P.

[0047] The image forming apparatus 1 has a circuit board 100. The circuit board 100 is composed of a wiring board 101 made of an insulator and electronic components 111 and 121 soldered to the wiring board 101. Conductor wiring is provided on and inside the wiring board 101 to electrically connect to the electronic components 111 and 121. The circuit board 100 has functions such as converting AC current supplied from outside the image forming apparatus 1 into DC current and converting input voltage to obtain a predetermined voltage required for the image formation process.

[0048] When image information is transmitted to the image forming apparatus 1, the photosensitive drum 11, which is a rotating body, is rotated in the direction of arrow R at a predetermined peripheral speed (process speed) based on a print start signal.

[0049] The image forming apparatus 1 has a scanner unit 50 as an exposure means. The scanner unit 50 irradiates a laser beam onto the photosensitive drum 11 based on input image information. The scanner unit 50 includes a laser oscillator that outputs the laser beam, a polygon mirror and a lens for irradiating the laser beam onto the photosensitive drum 11, a scanner motor for rotating the polygon mirror, and a frame that supports these components.

[0050] The photosensitive drum 11 is pre-charged by the charging roller 17, and when irradiated with laser light, an electrostatic latent image corresponding to the image information is formed on the photosensitive drum 11. Thereafter, the toner contained in the toner container 230a is conveyed to the photosensitive drum 11 by the developing roller 12, whereby the electrostatic latent image is developed and a toner image is formed on the photosensitive drum 11.

[0051] In parallel with the image forming operation described above, recording materials P are fed from the feed tray 4. A pickup roller 3, a feed roller 5a, a separation roller 5b, and a pair of conveying rollers 5c are provided on the conveyance path of the image forming apparatus 1. The pickup roller 3 comes into contact with the uppermost recording material P stored in the feed tray 4 and feeds the recording material P by rotating. The feed roller 5a and the separation roller 5b that is in pressure contact with it form a separation nip. If multiple sheets of recording materials P are fed into the separation nip due to the influence of friction between the recording materials P, the feed roller 5a and the separation roller 5b separate the multiple sheets of recording materials P and feed only the uppermost one downstream.

[0052] The recording material P fed from the feed tray 4 is conveyed by a pair of conveying rollers 5c toward a transfer roller 7. A transfer bias is applied to the transfer roller 7, so that the toner image formed on the photosensitive drum 11 is transferred onto the recording material P. The recording material P onto which the toner image has been transferred by the transfer roller 7 is heated and pressurized by a fixing device 9, so that the toner image is fixed onto the recording material P. The fixing device 9 is composed of a heating roller 9a incorporating a fixing heater, and a pressure roller 9b that is urged toward the heating roller 9a. Then, the recording material P onto which the toner image has been fixed is discharged onto a discharge tray 14 by a pair of discharge rollers 10.

[0053] When forming images on both sides of the recording material P, the pair of discharge rollers 10 switches back the recording material P with the image formed on its first side, thereby guiding the recording material P to the double-sided conveying path 16. The recording material P guided to the double-sided conveying path 16 is conveyed again toward the transfer roller 7 by the pair of double-sided conveying rollers 5d and the pair of conveying rollers 5c. After an image is formed on the second side of the recording material P, which is behind the first side, by the transfer roller 7, the recording material P is discharged to the discharge tray 14 by the pair of discharge rollers 10.

[0054] <Resupply department layout and configuration> A replenishing pack (replenishing container) 210 for replenishing toner can be detachably attached to the image forming apparatus 1. The image forming apparatus 1 and the replenishing pack 210 can be collectively called an image forming system.

[0055] The supply unit 200 and the supply pack 210 will be described with reference to FIGS.

[0056] Figure 5 is a side view of the image forming apparatus 1 illustrating the arrangement of the supply unit 200. Figure 5 is a side view of the image forming apparatus 1 as viewed from the direction of the rotation axis of the photosensitive drum 11. In Figure 5, the exterior cover 71 and at least a part of the left side plate frame 73 are omitted, and the interior of the image forming apparatus 1 is shown.

[0057] The image forming apparatus 1 is provided with a supply unit 200. A supply pack 210 can be attached to the supply unit 200, and toner can be supplied from the supply pack 210 to the toner storage chamber 230a. Therefore, when the amount of toner remaining in the toner storage chamber 230a becomes low, toner can be supplied to the toner storage chamber 230a from outside the image forming apparatus 1 without removing the toner storage chamber 230a and the process unit 500 from the housing 72.

[0058] The supply unit 200 includes an operation unit 201, a cylindrical mounting unit 202, and a supply path 203 that connects the toner storage chamber 230a and the mounting unit 202.

[0059] Of the supply unit 200, the attachment unit 202 and supply path unit 203 are provided in the developing device 230. In this embodiment, the attachment unit 202 and supply path unit 203 are formed integrally with the developing frame 30 and are part of the developing frame 30. The operation unit 201 is provided in the housing 72. The attachment unit 202 and the operation unit 201 are configured to be able to receive a supply pack 210.

[0060] The developing device 230 functions as a receiving unit (support unit, receiving unit) that receives the replenishment pack 210. The replenishment pack 210 is removably attached to the attachment portion 202.

[0061] 6 is a perspective view of supply pack 210. Supply pack 210 includes a container portion (supply toner storage portion, pouch portion) 211 containing the toner to be replenished, and a cylindrical insertion portion 212. An opening 213 is provided on the side of insertion portion 212 as an outlet for discharging the toner stored in pouch portion 211. Supply pack 210 also includes shutter portion 214 that opens and closes opening 213. Shutter portion 214 covers opening 213 in an openable and closable manner. Insertion portion 212 and shutter portion 214 are inserted into attachment portion 202 and operation portion 201 when supply pack 210 is attached to supply port 200.

[0062] It can also be said that the attachment portion 202 and the supply path portion 203 are part of the developing unit frame 30. The developing device 230 and the developing unit frame 30 are configured to be movable with respect to the photosensitive unit 300. In other words, the attachment portion 202, the supply path portion 203, and the toner accommodating chamber 230a are movable with respect to the photosensitive unit 300. In other words, the developing device 230 and the developing unit frame 30 are configured to be movable with respect to the photosensitive drum 11 or the housing 72 while being housed in the housing 72. In other words, it can also be said that the attachment portion 202 and the supply path portion 203 are configured to be movable with respect to the photosensitive drum 11 or the housing 72.

[0063] The operation unit 201 is located on a top surface 240, which will be described later, and has an operation unit opening 204. The toner supplied from the supply pack 210 moves in this order through the attachment unit 202 and the supply path 203, and is finally supplied to the toner storage chamber 230a.

[0064] <Refill container installation procedure> Next, a procedure for replenishing toner using the replenishing pack 210 will be described with reference to FIG.

[0065] FIG. 7 is a perspective view of the image forming apparatus 1, showing a state in which the supply pack 210 is inserted into the supply unit 200. As shown in FIG.

[0066] The discharge tray 14 covers the supply unit 200 and is movable between a closed position (loading position, covered position) where the recording material P discharged from the discharge port 15 can be stacked, and an exposed position (open position) where the supply unit 200 is exposed. When the discharge tray 14 is in the closed position, the discharge tray 14 covers the operation unit 201 and the attachment unit 202 of the supply unit 200. When the discharge tray 14 is in the exposed position, the operation unit 201 and the attachment unit 202 of the supply unit 200 are exposed, allowing the attachment of a supply pack 210.

[0067] When replenishing toner, the recording material P stacked on the discharge tray 14 is removed, and the discharge tray 14 is opened and moved to the open position shown in Fig. 7. When the discharge tray 14 is opened, the supply unit 200, the top surface 240 provided adjacent to the supply unit 200, the operation unit 201 of the supply unit 200, and the attachment unit 202 are exposed.

[0068] 7, the supply pack 210 is inserted into the exposed supply unit 200. In this state, the supply pack 210 is inserted into the operation unit opening 204 of the operation unit 201 and is received in the toner receiving unit 201. When the operation unit 201 is rotated in this state, the shutter 214 covering the opening 213 of the supply pack 210 moves, and the opening 213 is opened. The container unit 211 is deformed, and the toner is discharged from the opening 213. The toner discharged from the opening 213 passes through the attachment unit 202 and the supply path 203 and is replenished to the toner storage chamber 230a.

[0069] After the toner supply is completed, the supply pack 210 is removed from the image forming apparatus 1. The image forming apparatus 1 can perform image forming operations with the supply pack 210 removed.

[0070] <Movement of the developer container when opening and closing the output tray> Next, with reference to FIG. 8, the movement of the developing device 230 when the discharge tray 14 is opened and closed for toner replenishment will be described.

[0071] As described above, the supply pack 210 is received by the attachment portion 202. At this time, a force for attaching the supply pack 210 acts on the attachment portion 202 of the developing device 230. Therefore, when attaching the supply pack 210, the developing device 230 is supported by a support unit 250 (described later), thereby making it possible to suppress movement of the developing device 230.

[0072] When the supply pack 210 is attached to the supply unit 200, the discharge tray 14 is opened. In this embodiment, the developing device 230 is supported by the support unit 250 in conjunction with the opening of the discharge tray 14. As a result, the posture of the developing device 230 can be stabilized when the supply pack 210 is attached.

[0073] Fig. 8 is an explanatory diagram of the support unit 250 according to this embodiment. Fig. 8(a) is a diagram showing the support unit 250 in a retracted state. Fig. 8(b) is a diagram showing the support unit 250 in a support start state. Fig. 8(c) is a diagram showing the support unit 250 in a support state. Figs. 8(a), 8(b), and 8(c) are side views seen along the direction of the rotation axis of the photosensitive drum 11.

[0074] In this embodiment, the support unit 250 includes a tray gear (driving member, drive gear) 231, an idler gear (intermediate member) 232, and a support member (moving member) 233. The tray gear 231 and the idler gear 232 function as a connecting portion (connecting member) that connects the discharge tray 14 and the support member 233 so that the discharge tray 14 and the support member 233 move in conjunction with each other.

[0075] The supply pack 210 is attached to the attachment portion 202 from above in the vertical direction. The support member 233 supports the attachment portion 202 from below in the vertical direction. In this embodiment, the support member 233 is positioned below the attachment portion 202 in the vertical direction.

[0076] The support member 233 includes a first cam portion 233 a and a second cam portion 233 b serving as support portions for supporting the developing device 230 , and a gear portion 233 c that meshes with the idler gear 232 .

[0077] The first cam portion 233a is configured to support the supported portion 202f of the attachment portion 202.

[0078] The tray gear 231 is fixed to the discharge tray 14 and rotates in conjunction with the opening and closing of the discharge tray 14. In this embodiment, the tray gear 231 is engaged with a shaft provided at the rotation center of the discharge tray 14. The support member 233 is connected to the tray gear 231 via an idler gear 232.

[0079] The support member 233 is configured to be movable between a support position where the first cam portion 233a contacts the developing device 230 and supports the developing device 230, and a retracted position (second retracted position) retracted from the support position. The support member 233 moves between the support position and the retracted position in conjunction with the movement of the discharge tray 14. The state in which the support member 233 is in the support position is referred to as the support state of the support member 233 and the support unit 250. The state in which the support member 233 is in the retracted position is referred to as the retracted state of the support member 233 and the support unit 250.

[0080] When the discharge tray 14 is positioned at the exposed position, the support member 233 and the support unit 250 are in the supporting state, and the support member 233 is positioned at the supporting position. When the discharge tray 14 is positioned at the covered position, the support member 233 and the support unit 250 are in the retracted state, and the support member 233 is positioned at the retracted position.

[0081] When the support member 233 is in the support position, the support member 233 can support the developing device 230. In this state, the developing roller 12 is separated from the photosensitive drum 11 in this embodiment.

[0082] When the support member 233 is in the retracted position, in this embodiment, the first cam portion 233a of the support member 233 is separated from the developing device 230. Also, the developing roller 12 is in a position where it can develop the electrostatic latent image formed on the photosensitive drum 11 (in this embodiment, the developing roller 12 is in a position where it abuts against the photosensitive drum 11). Note that, if the electrostatic latent image can be developed by the developing roller 12, the support member 233 and the developing device 230 may be in contact with each other when the support member 233 is in the retracted position.

[0083] As described above, the support member 233 moves from the retracted position to the support position in conjunction with the movement of the discharge tray 14 from the covered position to the exposed position. When the support member 233 moves from the retracted position to the support position, the developing frame 30 moves from the development position to the retracted position (DS direction). When attaching the supply pack 210 to the attachment portion 202, the user moves the discharge tray 14 to the exposed position, so the current additional frame 30 is positioned at the retracted position.

[0084] In conjunction with the movement of the discharge tray 14 from the exposed position toward the covered position, the support member 233 moves from the support position to the retracted position. As the support member 233 moves from the support position to the retracted position, the developing frame 30 moves from the retracted position to the developing position (DC direction).

[0085] As described above, during image formation, the developing device 230 and the developing frame 30 are located at the developing position, and during toner replenishment, the developing device 230 and the developing frame 30 are located at the retracted position.

[0086] Meanwhile, the image forming apparatus 1 has an open / close sensor 239. The open / close sensor 239 is configured to be in an ON state when the discharge tray 14 is open and in an OFF state when the discharge tray 14 is closed. The open / close sensor 239 is switched to an ON state when it comes into contact with a second cam portion (contact portion, detected portion, detection target) 223b provided on the support member 233, and is switched to an OFF state when it separates from the second cam portion 233b.

[0087] When the discharge tray 14 is in the cover position and the support member 233 is in the retracted position, the open / close sensor 239 and the second cam portion 233b are separated. At this time, the signal state of the open / close sensor 239 is in the OFF state (first state). At this time, the control unit 199 allows the image forming operation to be performed.

[0088] When the discharge tray 14 is in the exposed position and the support member 233 is in the support position, the open / close sensor 239 comes into contact with the second cam portion 233b. At this time, the signal state of the open / close sensor 239 is ON (second state). The second state is a state different from the first state. At this time, the control unit 199 restricts the image forming operation from being performed. In other words, the control unit 199 can control the image forming apparatus 1 so that the image forming apparatus 1 does not start the image forming operation when the open / close sensor 239 is ON.

[0089] <Relationship between toner supply and images> As described above, the toner storage chamber 230a of the developing device 230 is replenished with toner from the replenishment pack 210.

[0090] Deteriorated toner, which has a higher degree of cohesion and is less likely to be charged than new toner, remains in the toner storage chamber 230a of the developing device 230. The more frequently image forming operations are performed using the developing device 230 (the longer the developing device 230 is used), the more the toner deteriorates.

[0091] When degraded toner is stored in the storage chamber 230a, new toner is replenished from the supply pack 210, and a solid image is printed, followed by a halftone image, and in some cases, dark and light areas are formed on the halftone image. This image is called a ghost image.

[0092] Ghost images will be explained using Figure 9. Figure 9 is an explanatory diagram of an image pattern for evaluating the level of a ghost image. In this image pattern, a patch is printed as a solid image, and then a halftone image is printed.

[0093] As shown in Figure 9, in the halftone image, the portion corresponding to the portion after the solid white image is printed is designated as region X, and the portion corresponding to the portion after the patch formed by the solid image is designated as region Y. When a ghost image occurs, the image density in region Y, which is one rotation of the developing roller 12 away from the patch, is higher than the image density in region X. In this embodiment, the level of the ghost image is evaluated by visually checking the density difference between region Y and region X.

[0094] The solid white image is formed by, for example, interrupting the exposure operation of the photosensitive drum 11.

[0095] <Refill toner regulations> When toner is replenished from the supply pack 210 to the developing device 230, the new toner is prevented from mixing with the deteriorated toner inside the developing chamber 230b, and the supply of new toner to the supply roller 20 is prevented, thereby preventing the occurrence of ghost images.

[0096] The regulation of toner by the wall portion 30b will be described using Figure 1. Figure 1 is a schematic cross section of the developing device 230 as seen along the longitudinal direction (rotational axis direction) of the developing roller 12. The left side of Figure 1 shows the state during image formation, with the developing device 230 and developing frame 30 in the developing position. The right side of Figure 1 shows the state during replenishment, with the developing device 230 and developing frame 30 in the retracted position. The left and right sides of Figure 1 are drawn so that the positions of the lowest part A of the supply roller 20 are aligned.

[0097] The toner inside the developing chamber 230b is taken in by the supply roller 20 and supplied to the developing roller 12 by the supply roller 20. In order to prevent the occurrence of ghost images, it is preferable to make the height of the upper end B of the wall portion 30b higher than the lowermost portion A of the supply roller 20. As described above, the developing device 230 and the developing frame 30 are located at the developing position during image formation, and are located at the retracted position when the supply pack 210 is attached to the attachment portion 202 and toner is replenished from the supply pack 210.

[0098] During image formation and replenishment, the upper end B of the wall 30b is located above the lowermost portion A of the supply roller 20 in the vertical direction. The wall 30b is located below the opening 30c. The wall 30b extends in a direction intersecting the horizontal direction. The lowermost portion of the storage chamber 230a is located below the upper end B of the wall 30b in the vertical direction.

[0099] The vertical height from the bottom A of the supply roller 20 to the top B of the wall 30b is hereinafter referred to simply as the wall height. The wall height during image formation is referred to as wall height C0, and the wall height during replenishment is referred to as wall height C1.

[0100] In this embodiment, the wall portion 30b is disposed so that the wall height is higher when the developing device frame 30 is at the retracted position than when the developing device frame 30 is at the developing position. In other words, the wall portion 30b is disposed so that the wall height C1 is higher than the wall height C0.

[0101] In this embodiment, the supply roller 20 and the upper end B of the wall portion 30b are located below the rotation axis Q in the vertical direction. When the developing device frame 30 moves from the development position to the retracted position, the upper end B of the wall portion 30b and the supply roller 20 move downward in the vertical direction. At this time, in the direction perpendicular to the rotation axis Q, the distance between the supply roller 20 and the rotation axis Q is longer than the distance between the upper end B of the wall portion 30b and the rotation axis. Therefore, the supply roller 20 moves further in the vertical direction than the upper end B of the wall portion 30b. Specifically, when the developing device 230 moves from the image forming position (development position) to the retracted position, the developing device frame 30 rotates 3.5° clockwise in FIG. 3 around the rotation axis Q. As a result, the wall height C1 during replenishment is higher than the wall height C0 during image formation, as shown in FIG. 1.

[0102] As described above, by raising the upper end B of the wall portion 30b relative to the lowermost portion A of the supply roller 20 during replenishment, it is possible to make it easier for the toner in the supply pack 210 to remain in the storage chamber 230a and for the deteriorated toner to remain in the developing chamber 230b. On the other hand, the height of the upper end B of the wall portion 30b relative to the lowermost portion A of the supply roller 20 is lowered during image formation to make it easier for the toner to circulate between the toner storage chamber and the developing chamber.

[0103] In order to demonstrate the effects of the present invention, Experiments 1 and 2 were conducted using the configuration of this embodiment, a comparative example, and a modified example.

[0104] <Experiment 1> (1-1: Configuration used in the experiment) [Example 1] Replenishment was carried out using the configuration of this example.

[0105] In Example 1, replenishment was performed in a state where the wall height C1 during replenishment was higher than the wall height C0 during image formation (C0>C1).

[0106] [Comparative Example 1] Figure 10 is a schematic cross-sectional view showing the posture of the developing device 230 during replenishment according to Comparative Example 1. The left side of Figure 10 shows a state in which the developing device 230 and the developing frame 30 are in the development position, and the left side of Figure 10 shows a state during image formation in which the developing device 230 and the developing frame 30 are in the development position. The right side of Figure 10 shows a state during replenishment in which the developing device 230 and the developing frame 30 are in the retracted position. The left and right sides of Figure 10 are drawn so that the positions of the lowest parts A of the supply roller 20 are aligned.

[0107] In Comparative Example 1, replenishment was performed in a state where the wall height C1 during replenishment was the same as the wall height C0 during image formation (C0=C1).

[0108] Comparative Example 2 Figure 11 is a schematic cross-sectional view showing the posture of the developing device 230 during replenishment according to Comparative Example 2. The left side of Figure 11 shows a state in which the developing device 230 and the developing frame 30 are in the development position, and the left side of Figure 11 shows a state during image formation in which the developing device 230 and the developing frame 30 are in the development position. The right side of Figure 11 shows a state during replenishment in which the developing device 230 and the developing frame 30 are in the retracted position. The left and right sides of Figure 11 are drawn so that the positions of the lowest parts A of the supply roller 20 are aligned.

[0109] In Comparative Example 2, replenishment was performed in a state where the wall height C1 during replenishment was lower than the wall height C0 during image formation (C0>C1).

[0110] [Variations] Figure 12 is a schematic cross-sectional view showing the attitude of the developing container during replenishment according to a modified example. The left side of Figure 12 shows the state during image formation, with the developing device 230 and developing frame 30 in the development position. The right side of Figure 12 shows the state during replenishment, with the developing device 230 and developing frame 30 in the retracted position. The left and right sides of Figure 12 are drawn so that the positions of the lowest part A of the supply roller 20 are aligned.

[0111] In the modified example, replenishment was performed in a state where the wall height C1 at the time of replenishment was higher than the wall height C0 at the time of image formation (C0>C1). In the modified example, the wall height C1 at the time of replenishment was higher than in Example 1, and the difference between the wall height C0 at the time of image formation and the wall height C1 at the time of replenishment was larger than in Example 1.

[0112] (1-2: Experimental conditions) <Before supply> The developing device 230 containing 50 g of deteriorated toner with a cohesion degree of 80% to 90% and the image forming apparatus 1 were left at 15° C. and 30% RH for one day to acclimate to the environment.

[0113] <Supply Pack> Toner was replenished to the developing device 230 using a replenishment pack 210 filled with 70 g of new toner having a cohesion of 30% to 40%.

[0114] <Supply> Developing device 230 was moved to the wall height C1 shown in Example 1, Comparative Example 1, Comparative Example 2, and Modified Example, respectively, and toner was replenished from replenishment pack 210. After the toner was replenished, stirring member 22 was rotated for 20 seconds while maintaining the same orientation as when the toner was replenished.

[0115] <Image evaluation> After removing the supply pack 210, the developing device 230 was returned to the position it was in when forming the image, and after printing 10 solid white images in succession, the image shown in Figure 9 was output, and the level of density difference in the halftone image (level of ghost image) was visually determined.

[0116] The density difference levels of halftone images (ghost image levels) are as follows: A: The difference in density is barely visible. B: A slight difference in density is visible. C: The difference in density is clearly visible. D: The difference in density is even more clearly visible than in C.

[0117] (1-3:Result) Table 1 below shows the wall height C0, wall height C1, and ghost image evaluation results for each configuration.

[0118] [Table 1]

[0119] First, we will describe the results of Comparative Examples 1 and 2. In the configuration of Comparative Example 1, the wall height C1 during replenishment is the same as the wall height C0 during image formation. In Comparative Example 2, the wall height C1 during replenishment is lower than in Comparative Example 1.

[0120] If toner is circulated within the developing device 230 during replenishment, the new toner replenished from the replenishment pack 210 and the deteriorated toner within the developing device 230 are likely to mix inside the developing chamber 230b. If a mixture of new toner and deteriorated toner is supplied to the developing roller 12 immediately after replenishment, a difference in density occurs between after a solid image is printed (area B in FIG. 9) and after a solid white image is printed (area A in FIG. 9), resulting in the occurrence of ghost images. The results of Comparative Example 1 and Comparative Example 2 show that the lower the wall height C1 during replenishment, the more likely ghost images are to occur.

[0121] Next, the results of Example 1 and the modified examples will be described. By increasing the wall height C1 during replenishment, the replenished toner can be retained in the storage chamber 230a. This suppresses the occurrence of ghost images caused by the replenished new toner mixing with degraded toner in the developing device 230. Furthermore, the results of Example 1 and the modified examples show that the higher the wall height C1 during replenishment, the greater the effect of suppressing the occurrence of ghost images.

[0122] <Experiment 2> In order to verify the effect of mixing the replenished new toner with the deteriorated toner in the developing device 230, the amount of charge of the toner on the developing roller 12 after printing a solid image and a solid white image was measured using the developing device 230 containing different toners.

[0123] Next, the experimental conditions will be explained.

[0124] (2-1: Developing device used in Experiment 2) In Experiment 2, a developing device 230 manufactured under the following conditions (a) to (f) was used.

[0125] (a) Developing device using only degraded toner As the developing device 230 under condition (a), a developing device 230 containing 120 g of deteriorated toner with a cohesion degree of 80% to 90% is used.

[0126] (b) Developing device of Example 1 As the developing device 230 under condition (b), a developing device 230 containing 50 g of toner with a cohesion degree of 80% to 90% was used, and 70 g of new toner with a cohesion degree of 30% to 40% was replenished under the same conditions as in Example 1 above.

[0127] (c) Developing device of Comparative Example 1 As the developing device 230 under condition (c), a developing device 230 containing 50 g of toner with a cohesion degree of 80% to 90% was used, and 70 g of new toner with a cohesion degree of 30% to 40% was replenished under the same conditions as in Comparative Example 1 above.

[0128] (d) Developing device of Comparative Example 2 As the developing device 230 under condition (d), a developing device 230 containing 50 g of toner with a cohesion degree of 80% to 90% was used, to which 70 g of new toner with a cohesion degree of 30% to 40% was replenished under the same conditions as in Comparative Example 2 above.

[0129] (e) Modified developing device As the developing device 230 under condition (e), a developing device 230 containing 50 g of toner with a cohesion degree of 80% to 90% is used, to which 70 g of new toner with a cohesion degree of 30% to 40% is replenished under the same conditions as in the above modified example.

[0130] (f) Developing device with new toner only As the developing device 230 under condition (f), a developing device 230 containing 120 g of new toner with a cohesion degree of 30% to 40% is used.

[0131] (2-2: Amount of toner charge after printing a solid image) Using the developing device 230 prepared under the conditions (a) to (f), the charge amount of the toner on the developing roller 12 after printing a solid image is measured.

[0132] Specifically, a solid image is printed using the developing device 230 manufactured under the conditions (a) to (f). After printing the solid image, the developing roller 12 is rotated once. The toner is collected from the portion of the surface of the developing roller 12 that is again covered with toner, and the charge amount of the collected toner is measured.

[0133] The charge amount per unit mass, Q / M (μC / g), was calculated from the mass M of the collected toner and the total charge amount Q measured directly with a coulomb meter, and was taken as the toner charge amount (Q / M).

[0134] (2-3: Measuring the toner charge amount after printing a solid white image) Using the developing device 230 prepared under the conditions (a) to (f), the charge amount of the toner on the developing roller 12 after printing a solid white image is measured.

[0135] Specifically, a solid image is printed using the developing device 230 manufactured under the conditions (a) to (f). After printing the solid image, the developing roller 12 is rotated 30 times. The toner is repaired from the portion of the surface of the developing roller 12 that was covered with toner again, and the charge amount of the repaired toner is measured.

[0136] (2-4: Image evaluation) Similar to the image evaluation described in Experiment 1, the image shown in Figure 9 was output using the developing device 230 created under conditions (a) and (f), and the level of density difference of the halftone image was visually determined.

[0137] (2-5:Result) Next, the results of Experiment 2 are shown in FIG.

[0138] 13 shows the toner charge amount Q / M after printing a solid white image and after printing a solid image for each of the developing devices 230 created under conditions (a) to (f). Table 2 shows the difference ΔQ / M (μC / g) between the toner charge amount after printing a solid white image and the toner charge amount after printing a solid image, and the level of ghost images.

[0139] [Table 2]

[0140] The results shown in Table 2 reveal that the higher the difference in toner charge amount ΔQ / M, the worse the level of ghost images becomes.

[0141] 13, it is believed that in the developing device 230 (a), due to toner deterioration, the charge amount after printing a solid image and the charge amount after printing a solid white image were both low, and the occurrence of ghost images was suppressed. Furthermore, in the developing device 230 (f), no density difference was visible. In the developing device 230 (f), the charge amount after printing a solid image and the charge amount after printing a solid white image were both high, and it is believed that no ghost images occurred. From these findings, it is believed that the greater the amount of new toner and deteriorated toner mixed during replenishment, the greater the toner charge amount difference ΔQ / M, and the worse the ghost images become.

[0142] As described above, according to the first embodiment and the modified example, by increasing the wall height C1 during toner replenishment, it is possible to suppress mixing of replenished toner and deteriorated toner in the developing chamber 230b. This suppresses the occurrence of ghost images caused by mixing of replenished toner and deteriorated toner, and makes it possible to provide an image forming apparatus 1 with fewer restrictions on toner replenishment at low cost.

[0143] The wall height of the wall portion 30b is preferably high during replenishment, but is preferably high enough to allow toner to circulate between the storage chamber 230a and the developing chamber 230b during image formation. Therefore, by making the wall height higher during replenishment (when the developing frame 30 is in the retracted position) than during image formation (when the developing frame 30 is in the developing position), it is possible to prevent the occurrence of ghost images while allowing toner to circulate during image formation.

[0144] Furthermore, to attach the supply pack 210 to the attachment portion 202, the user must move the discharge tray 14 from the covered position to the exposed position. When the discharge tray 14 is moved to the exposed position, the support member 233 moves the developing device frame 30 to the retracted position. Therefore, toner can be replenished from the supply pack 210 while the developing device frame 30 is in the retracted position and the wall height of the wall portion 30b is maintained higher than during image formation. In other words, the support member 233 restricts the attachment of the supply pack 210 to the attachment portion 202 and the replenishment of toner from the supply pack 210 when the developing device frame 30 is in the development position.

[0145] Furthermore, when attaching the supply pack 210 to the attachment portion 202, the support member 233 supports the existing additional frame body 30, so the user can replenish toner from the supply pack 210 with the wall portion 30b held high.

[0146] Although the image forming apparatus 1 capable of forming monochrome images is exemplified in this embodiment, the present invention can be applied to an image forming apparatus capable of forming color images.

[0147] Furthermore, in this embodiment, a printer is exemplified as the image forming apparatus 1, but the present invention can also be applied to other image forming apparatuses such as a copying machine, a facsimile machine, or a multifunction machine that combines the functions of these.

[0148] The present invention can also be applied to an image forming apparatus that uses a recording material carrier such as a conveyor belt for conveying a recording material P, and transfers toner images of different colors onto the recording material P carried on the recording material carrier in a superimposed manner. The present invention can also be applied to an image forming apparatus that uses a so-called intermediate transfer member. [Explanation of symbols]

[0149] 1. Image forming device 12 Developing roller 20 Supply roller 30 Developing frame 30a, 30b wall 30c opening 210 Supply Pack 230 Developing device 300 Photosensitive unit (drum unit) 500 process units

Claims

1. A developing device to which a supply container is removably attached, a developing roller for developing the electrostatic latent image formed on the image carrier; a supply roller that contacts the developing roller and supplies developer to the developing roller; a mounting portion to which the supply container is removably attached; a frame having a storage chamber configured to store the developer replenished from the supply container, a developing chamber in which the developing roller and a supply roller are disposed, and a wall portion extending in a direction intersecting a horizontal direction and separating the developing chamber from the storage chamber so as to form an opening communicating the developing chamber with the storage chamber, the frame being configured to be movable between a first position where the developing roller develops the electrostatic latent image and a second position retracted from the first position; a developing device having a moving member that moves the frame body from the first position to the second position; a cover member configured to be movable between a cover position that covers the mounting portion and an exposed position that exposes the mounting portion; and In the vertical direction, the wall portion is located below the opening, and the upper end of the wall portion is located above the lowermost part of the supply roller, When the supply container is attached to the attachment portion, the frame is located at the second position, the wall portion is disposed such that a height from the lowermost portion of the supply roller to the upper end of the wall portion in the vertical direction is higher when the frame body is in the second position than when the frame body is in the first position; an image forming apparatus, wherein the moving member moves the frame from the first position to the second position in conjunction with the movement of the cover member from the cover position toward the exposed position;

2. 2. The image forming apparatus according to claim 1, wherein the lowermost portion of the storage chamber is located below the upper end of the wall portion in the vertical direction.

3. the frame is rotatable about a rotation axis to move between the first position and the second position; 3. The image forming apparatus according to claim 1, wherein the distance between the supply roller and the rotation shaft in a direction perpendicular to the rotation shaft is longer than the distance between the upper end of the wall portion and the rotation shaft.

4. the supply roller and the upper end of the wall portion are positioned below the rotation shaft in the vertical direction; 4. The image forming apparatus according to claim 3, wherein when the frame body moves from the first position to the second position, the upper end of the wall portion and the supply roller move downward in the vertical direction.

5. further comprising an agitating member for agitating the developer; 5. The image forming apparatus according to claim 1, wherein the stirring member is accommodated in the accommodation chamber.

Images