Developing device and image forming apparatus

Abstract

To provide a developing device whose manufacturing cost is reduced.SOLUTION: A storage chamber in which a developer containing a toner is stored; a developer bearing member which bears the developer on a surface thereof and rotates in a predetermined direction; a supply member which is arranged below the developer bearing member and supplies the developer to the surface of the developer bearing member; A layer regulating member including a columnar portion configured to regulate a layer thickness of the developer supplied onto the developer carrier, the developer carrier, the supply member, and the layer regulating member being accommodated in the accommodation chamber, a connection partition wall including a guide portion configured to guide the developer being formed between the supply member and the layer regulating member, wherein the guide portion is formed such that a virtual extension line connecting a first position which is an end portion on the supply member side and a second position which is an end portion on the regulating member side passes below a center line of the columnar portion of the regulating member.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present disclosure relates to a developing device and an image forming apparatus. [Background technology]

[0002] A developing device that suppresses adhesion of toner to a layer regulating member over time and accurately regulates the layer thickness of a developer is known (see, for example, Patent Document 1). The developing device described in Patent Document 1 includes a developer carrier that holds developer, a developer supply member that supplies the developer to the developer carrier, a layer regulating member that regulates the layer thickness of the developer held on the developer carrier, and a blocking member that is provided between the layer regulating member and the developer supply member and blocks the path of the developer supplied from the developer supply member toward the layer regulating member. The blocking member includes a guide portion that guides the developer toward the developer carrier. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-192021 Summary of the Invention [Problem to be solved by the invention]

[0004] In the developing device described in Patent Document 1, the damming member having a guide portion that guides the developer is configured as a separate body from the developing container that contains the developer, which increases the manufacturing cost of the developing device.

[0005] An object of one aspect of the present invention is to provide a developing device and an image forming apparatus that can reduce manufacturing costs. [Means for solving the problem]

[0006] A developing device according to one aspect of the present disclosure comprises a storage chamber for storing developer including toner, a developer carrier that carries the developer on its surface and rotates in a predetermined direction, a supply member that is disposed below the developer carrier and supplies the developer to the surface of the developer carrier, and a layer regulating member that is disposed downstream of the supply member in the rotation direction of the developer carrier and has a cylindrical portion that regulates the layer thickness of the developer supplied onto the developer carrier, wherein the storage chamber contains the developer carrier, the supply member, and the layer regulating member, and a connecting partition wall that has a guide portion formed thereon to guide the developer is formed between the supply member and the regulating member, and the guide portion is formed so that a virtual extension line connecting a first position that is the end on the supply member side and a second position that is the end on the regulating member side passes below the center line of the cylindrical portion of the regulating member. [Effects of the Invention]

[0007] According to the developing device according to one aspect of the present disclosure, the manufacturing cost can be reduced. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic cross-sectional view showing an image forming apparatus according to an embodiment. [Figure 2] FIG. 2 is a perspective view of a developing unit and a process unit according to the embodiment. [Figure 3] FIG. 2 is a cross-sectional view of a developing unit and a process unit according to the embodiment. [Figure 4] FIG. 2 is a perspective view of the inside of a developing unit according to the embodiment. [Figure 5] FIG. 2 is a partial enlarged view of a developing unit according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments will be described with reference to the drawings. In the drawings, the same or equivalent elements are designated by the same reference numerals, and redundant description will be omitted.

[0010] 1 is a schematic cross-sectional view showing an image forming apparatus according to an embodiment of the present invention. The image forming apparatus 1 is, for example, a multifunction peripheral having a copying function, a printer function, a scanner function, a facsimile function, and the like.

[0011] The image forming apparatus 1 includes a printing device 10, an image reading device 20, and a document transport device 30. The image forming apparatus 1 transmits image data read by the image reading device 20 to an external device, and forms an image on the document in a single color or multiple colors using the image data of the read document or image data received from an external device.

[0012] The printing device 10 includes a paper feed unit 110, a pair of conveying rollers 120, a pair of registration rollers 130, an image forming unit 140, a pair of discharge rollers 150, and a discharge tray 160. Inside the printing device 10, a conveying path S1 is formed for sending paper fed from the paper feed unit 110 to the discharge tray 160 via the pair of conveying rollers 120, the pair of registration rollers 130, the image forming unit 140, and the pair of discharge rollers 150.

[0013] The paper feed unit 110 is disposed below the image forming unit 140 and includes a paper feed tray 111 that stores paper, a pickup roller 113 provided above one end of the paper feed tray 111, a paper feed roller 114 that is disposed downstream of the pickup roller 113 in the paper transport direction, and a separation roller 115 that is pressed against the paper feed roller 114. Furthermore, multiple paper feed units 110 may be provided.

[0014] The paper feed tray 111 further includes a rotary inner tray 112 for bringing the stacked paper sheets into contact with a pickup roller 113 .

[0015] In the paper feed unit 110, the internal tray 112 is rotated (raised) to bring the stored paper into contact with the pickup roller 113, and the contacted paper is then picked up by the pickup roller 113 and guided to the paper feed roller 114. The paper picked up by the pickup roller 113 is separated into individual sheets as it passes between the paper feed roller 114 and the separation roller 115, and the paper is transported to the transport path S1 by the transport roller pair 120 and sent to the registration roller pair 130.

[0016] The pair of registration rollers 130 temporarily stops the paper and aligns the leading edge of the paper, and then sends the stopped paper toward the nip area between an intermediate transfer belt 146a (fixing belt) and a transfer roller 147, which will be described later, in accordance with the timing when a toner image is formed in the image forming unit 40.

[0017] The image forming section 140 includes a photosensitive drum 141, a charger 142, an exposure unit 143, a developing unit (developing device) 144, a cleaning blade 145, an intermediate transfer belt unit 146, a transfer roller 147, and a fixing device 60. The photosensitive drum 141, the charger 142, and the cleaning blade 145 are unitized, and these constitute a process unit 148.

[0018] The image data handled by the image forming unit 140 corresponds to color images of four colors: black (K), cyan (C), magenta (M), and yellow (Y). For this reason, four image forming stations for forming toner images, each consisting of a process unit 148 including a photosensitive drum 141, a charger 142, and a cleaning blade 145, and a corresponding developing unit 144, are provided to form four types of images corresponding to each color. Four toner cartridges 149 are provided so that the toner corresponding to each image forming station can be supplied.

[0019] The photosensitive drum 141 has a cylindrical conductive substrate and a photosensitive layer formed on the surface of the substrate that is insulating in the dark and becomes conductive when irradiated with light. The charger 142 charges the surface of the photosensitive drum 141 to a predetermined potential. The exposure unit 143 is a laser scanning unit equipped with a laser emitter, a reflecting mirror, and the like. The exposure unit 143 exposes the surface of the photosensitive drum 141, which is charged to a predetermined potential, to light, thereby forming an electrostatic latent image on the surface of the photosensitive drum 141 according to image data. The development unit 144 develops the electrostatic latent image formed on the surface of the photosensitive drum 141 with toner, making it visible and forming a toner image on the surface of the photosensitive drum 141. The cleaning blade 145 removes and collects toner remaining on the surface of the photosensitive drum 141 after the toner image has been intermediately transferred to an intermediate transfer belt unit 146 (described later).

[0020] The intermediate transfer belt unit 146 includes an intermediate transfer belt 146a, a drive roller 146b, a driven roller 146c, and four intermediate transfer rollers 146d. The intermediate transfer belt unit 146 is disposed above the photosensitive drums 141. The intermediate transfer belt 146a is stretched across the drive roller 146b and the driven roller 146c, and rotates in a movement direction F1 when the drive roller 146b is rotated by a drive source (not shown). The intermediate transfer belt 146a is also disposed so as to contact each photosensitive drum 141 via intermediate transfer rollers 146d provided corresponding to each photosensitive drum 141, and the toner images of each color formed on each photosensitive drum 141 are sequentially intermediately transferred onto the intermediate transfer belt 146a, which is rotated by the drive roller 136b.

[0021] The transfer roller 147 is disposed opposite the drive roller 146b so as to contact the intermediate transfer belt 146a. The toner images sequentially transferred onto the intermediate transfer belt 146a are transferred onto the paper fed from the registration roller pair 130 when the paper passes through the transfer nip area, which is the contact area between the transfer roller 147 and the intermediate transfer belt 146a.

[0022] The paper with the transferred toner image is transported to fixing device 60. Fixing device 60 has fixing roller 61 with heat source 66 inside, pressure roller 62 with a heat-resistant elastic layer on its surface and provided so as to abut against fixing roller 61, and temperature sensor 67 that detects the surface temperature of fixing roller 61, and the surface of fixing roller 61 is heated to a predetermined temperature based on the detection result of temperature sensor 67. The toner transferred to the paper is fixed to the paper by heat and pressure as it passes through the fixing nip area, which is the abutting area between fixing roller 61 and pressure roller 62.

[0023] The paper on which the toner image has been fixed by the fixing device 60 is conveyed to a discharge tray 160 by a pair of discharge rollers 150 .

[0024] Furthermore, when an image is to be formed on the back side of the paper in addition to the front side, the paper is switched back by the discharge roller pair 150 and conveyed to the reverse path S2. The paper conveyed on the reverse path S2 is reversed by the reverse roller pair 170 while being conveyed on the reverse path S2, and is conveyed to the registration roller pair 130. Thereafter, the paper, on whose back side an image has been formed in the same manner as on the front side, is conveyed to the discharge tray 160.

[0025] The image reading device 20 reads an image to be printed by the printing device 10 and generates image data. An original document table 22 made of a transparent member on which an original document is placed face down is provided on the top surface of the image reading device 20. An original document transport device 30 (described later) is provided above the original document table 22 so as to be movable via a hinge between a closed position where the original document table 22 is closed and an open position where the original document table 22 is exposed. When the original document transport device 30 is in the open position, an original document can be placed manually on the original document table 22.

[0026] An optical reading unit 24 having a light source is provided below the document placing table 22. The optical reading unit 24 moves in the scanning direction (the direction of the arrow F2 in FIG. 1) while transmitting reflected light from a document placed on the document placing table 22 to an imaging means 25 to convert the reflected light into electronic data. The image reading device 20 also has a transported document reading unit 21 made of a transparent member on the opposite side of the document placing table 22 from the scanning direction, which is a reading unit that reads a document transported from a document transport device 30 (described later).

[0027] An operation panel (not shown) is provided on the front side of the image reading device 20. The operation panel displays various information and accepts input from the user. The operation panel is an example of a display operation unit, and includes a display panel, a touch panel, hard keys, etc.

[0028] The document transport device 30 includes a paper feed tray 31, a paper feed unit 32, a pair of transport rollers 33, a pair of discharge rollers 34, a discharge tray 35, and a document transport path S3.

[0029] The paper feed tray 31 is a tray on which multiple documents can be placed. The paper feed unit 32 transports the multiple documents placed on the paper feed tray 31 one by one toward the document transport path S3. The document transport path S3 is provided with a pair of transport rollers 33, a transported document reading unit 21, and a discharge roller pair 34. The documents sent one by one to the document transport path S3 are imaged by the imaging means 25 via the optical reading unit 24 in the transported document reading unit 21 and converted into electronic data. The documents read by the transported document reading unit 21 are discharged to the discharge tray 35 by the discharge roller pair 33. The discharge tray 35 is a tray on which multiple documents can be placed in a stack.

[0030] FIG. 2 is a perspective view of one image forming station (developing unit and process unit) according to an embodiment. FIG. 3 is a cross-sectional view of one image forming station according to an embodiment. FIG. 4 is a perspective view of the inside of a developing unit included in an image forming station according to an embodiment. In FIG. 4, upper housing 211 is not shown in order to explain the inside of developing unit 144. Developing unit 144 is mounted inside image forming apparatus 1 so that the direction indicated by the arrow pointing to the upper left in FIGS. 2 and 4 is the direction toward the rear side of image forming apparatus 1, and the direction indicated by the arrow pointing to the lower right is the direction toward the front side of image forming apparatus 1.

[0031] 3, the developing unit (developing device) 144 has a storage chamber 221 that stores developer including toner. The developing unit 144 also has a developing roller (developer carrier) 202, a regulating roller (layer regulating member) 203, a first conveying screw 204, and a second conveying screw 205. The first conveying screw 204 is an example of a supplying member.

[0032] The containing chamber 221 contains the developer, as well as the developing roller 202, the regulating roller 203, the first conveying screw 204, and the second conveying screw 205.

[0033] Here, the storage chamber 221 includes a supply chamber 221A that accommodates the developer, the developing roller 202, the regulating roller 203, and the first conveying screw 204, and a stirring chamber 221B that accommodates the developer and the second conveying screw 205. In detail, the supply chamber 221A and the stirring chamber 221B that configure the storage chamber 221 are formed by the developer tank 201 that is configured by the upper housing 211 and the lower housing 212.

[0034] Here, lower housing 212 has a shape that is open at the top and has partition wall 223. Upper housing 211 is a cover member that covers the top of lower housing 212, and when upper housing 211 is attached to lower housing 212, partition wall 223 divides the interior into supply chamber 221A that houses developing roller 202, regulating roller 203 and first conveying screw 203, and stirring chamber 221B that houses the second conveying screw.

[0035] As described above, developer is stored in supply chamber 221A and stirring chamber 221B. The developer used in developing unit 144 of the present disclosure is a developer containing non-magnetic toner and magnetic carrier (two-component developer), but may also be a one-component developer consisting of only toner.

[0036] Supply chamber 221A has an opening 240 that opens toward photosensitive drum 141. In the region of supply chamber 221A corresponding to opening 240, developing roller 202, which carries a portion of the developer stored in supply chamber 221A on its surface and rotates in a predetermined direction R1, is arranged so as to face photosensitive drum 141. Developing roller 202 has a non-magnetic sleeve that can be rotated in the predetermined direction R1 by a drive source (not shown), and a non-rotating magnet roller inside the sleeve, in which magnets having a shape extending in the direction of the rotation axis of the sleeve are arranged in multiple circumferential directions of the sleeve.

[0037] Below the developing roller 202 in the supply chamber 221A, a first conveying screw 204 for supplying developer to the surface of the developing roller 202 (surface of the sleeve) is rotatably provided.

[0038] The first conveying screw 204 has a rotating shaft 214 and a spiral blade 215 formed on the outer side of the rotating shaft 214. The first conveying screw 204 is rotated in a rotation direction R2 by a drive source (not shown). When the first conveying screw 204 is rotating in the rotation direction R2, the spiral blade conveys the developer stored in the supply chamber 221A in the direction of the arrow E1 in FIG. 4, i.e., from the rear side to the front side of the image forming apparatus 1, while stirring the developer. A portion of the developer conveyed in the direction of the arrow E1 by the first conveying screw 204 is supplied to the developing roller 202. In other words, the first conveying screw 204 is disposed below the developing roller 202 and supplies a portion of the developer stored in the supply chamber 221A to the surface of the developing roller 202.

[0039] Partition wall 223 separating supply chamber 221A and stirring chamber 221B has communication openings at both ends in the rotational axis direction of first conveyor screw 204 that communicate with stirring chamber 221B, which houses second conveyor screw 205. Therefore, the developer transported to the front side of the paper in FIG. 3, i.e., the front end of developing unit 144 (of image forming apparatus 1) by the first conveyor screw rotated in rotation direction R2, is sent to stirring chamber 221B through first communication opening 224A provided on the front side of partition wall 223 (see arrow E2 in FIG. 4). As described above, second conveyor screw 205 is housed in stirring chamber 221B. Like the first conveying screw 204, the second conveying screw 205 has a rotating shaft 216 and a spiral blade 217 formed on the outer surface of the rotating shaft 216. When rotated by a drive source (not shown), the second conveying screw 205 conveys the developer sent to the stirring chamber 221B through the first communication port 224A toward the rear side of the image forming apparatus 1 (arrow E3 in FIG. 4). The developer conveyed by the second conveying screw 205 to the rear end of the developing unit 114 (of the image forming apparatus 1) is sent to the supply chamber 221A through the second communication port 224B provided in the partition wall 223 (arrow E4 in FIG. 4). In this way, the developer contained in the containing chamber 211 circulates between the supply chamber 211A and the stirring chamber 211B while being stirred and conveyed by the first conveying screw 204 and the second conveying screw 205. At this time, the toner in the developer is frictionally charged with the carrier to have a predetermined charge.

[0040] A portion of the developer transported within the supply chamber 221A by the first transport screw 204 is drawn up onto the surface of the sleeve by the magnetic roller of the developing roller 202, and when the sleeve is rotated in a predetermined direction R1 by a drive source (not shown), the developer drawn up and carried on the sleeve also moves in the predetermined direction R1.

[0041] The layer thickness of the developer pumped up onto the sleeve is regulated by the regulating roller 203 as it moves in the predetermined direction R1. The regulating roller 203 is located downstream of the first conveying screw 204 in the predetermined direction R1, which is the rotation direction of the developing roller 202, and has a columnar (or cylindrical) portion that regulates the layer thickness of the developer supplied onto the developing roller 202. The regulating roller 203 is disposed in the supply chamber 221A above the first conveying screw 204 and below the developing roller 202, with the central axis of the columnar portion parallel to the developing roller 202. The regulating roller 203 is disposed such that a gap of a predetermined width is formed between the surface of the columnar portion and the surface of the sleeve of the developing roller 202 in order to regulate the layer thickness of the developer carried on the sleeve of the developing roller 202. The developer carried on the sleeve of the developing roller 202 is regulated to a predetermined thickness as it passes through the gap. The regulating roller 203 is supported and housed in the supply chamber 221A so as not to rotate, but it may be rotatable.

[0042] The developer on the sleeve of the developing roller 202, whose layer thickness is regulated by the regulating roller 203, moves in a predetermined direction R1, and at the portion facing the photosensitive drum 141, the toner in the developer is supplied to the electrostatic latent image formed on the photosensitive drum 141.

[0043] For this reason, a developing bias, which is a predetermined voltage, is supplied to the sleeve of the developing roller 202 from a developing power supply (not shown). Due to the potential difference between this developing bias and the electrostatic latent image formed on the photosensitive drum 141, toner charged to a predetermined amount moves to the photosensitive drum 141, and the electrostatic latent image is developed. Note that the toner consumed in development is supplied from the corresponding toner cartridge 149 to the stirring chamber 221B via a toner supply port 222 provided on the front side of the developing unit 144.

[0044] Next, the detailed structure of the developing unit 144 will be described.

[0045] FIG. 5 is a partial enlarged view of the developing unit 114 according to the embodiment.

[0046] Supply chamber (accommodation chamber) 221A has a semi-cylindrical first semi-cylindrical wall 231 that forms a first space in which regulating roller 202 is accommodated, a semi-cylindrical second semi-cylindrical wall 232 that forms a second space in which first conveying screw (supply member) 204 is accommodated, and a connecting partition wall 233 that is provided between the first space and the second space so as to connect the first semi-cylindrical wall 231 and the second semi-cylindrical wall 232. In detail, in lower housing 212 of developing unit 144 that constitutes supply chamber 221A together with upper housing 211, there are formed: semi-cylindrical first semi-cylindrical wall 231 that forms the first space, which is a space in which regulating roller 203 is accommodated; semi-cylindrical second semi-cylindrical wall 232 that forms the second space, which is a space in which first conveying screw (supply member) 204 is accommodated; and a connecting partition wall 233 that is provided between the first space and the second space so as to connect the first semi-cylindrical wall 231 and the second semi-cylindrical wall 232.

[0047] Here, the first semi-cylindrical wall 231 is a recess having a wall formed in a semi-cylindrical shape, and accommodates the regulating roller 203. That is, the first space accommodating the regulating roller 203 has the first semi-cylindrical wall 231 in a semi-cylindrical shape.

[0048] The second semi-cylindrical wall 232 is a recess having a wall formed in a semi-cylindrical shape, and accommodates the first conveying screw 204. That is, the second space accommodating the first conveying screw 204 has the second semi-cylindrical wall 232 in a semi-cylindrical shape.

[0049] The connecting partition wall 233 is provided between the first semi-cylindrical wall 231 and the second semi-cylindrical wall 232, and separates the first semi-cylindrical wall 231 from the second semi-cylindrical wall 232. In other words, the connecting partition wall 233 separates the conveying screw 204 from the regulating roller 203. The upper part of the connecting partition wall 233 is open, and the space on the conveying screw 204 side and the space on the regulating roller 203 side are connected to each other, and the conveying screw 204, the developing roller 202, and the regulating roller 203 are arranged in a common space (supply chamber 221A).

[0050] The connecting partition wall 233 has a guide portion 236 that guides the developer to the developing roller 202. The guide portion 236 is, for example, planar. If the end of the guide portion 236 on the first conveying screw 204 side is defined as a first position 237 and the end of the guide portion 236 on the regulating roller 203 side is defined as a second position 238, the first position 237 is connected to the end of the second semi-cylindrical wall 232 on the regulating roller 203 side, and the second position 238 is connected to the end of the first semi-cylindrical wall 231 on the first conveying screw 204 side. Here, an imaginary extension line L connecting the first position 237 and the second position 238 is configured to pass below the center O (of the cylindrical portion) of the regulating roller 203. That is, in the cross-sectional view of FIG. 5, the guide portion 236 is formed so that the imaginary extension line L extended toward the regulating roller 203 side passes below the regulating roller 203.

[0051] That is, a connecting partition wall having a guide portion 236 for guiding the developer is formed between the first conveying screw 204 and the regulating roller 203 of the supply chamber 221A. The guide portion 236 is formed so that an imaginary extension line L connecting a first position 237, which is the end of the first conveying screw 204 side, and a second position 238, which is the end of the regulating roller 203 side, passes below the center line of the cylindrical portion of the regulating roller 203. By configuring the guide portion 236 in this manner, the layer thickness is regulated by the gap between the cylindrical portion of the regulating roller 204 and the sleeve surface of the developing roller 202. Any developer that slides down the cylindrical portion of the regulating roller 204 and fails to pass through the gap can be received (as if scooped) at the second position 238 and reliably guided to the first conveying screw 204. The second position 238 is positioned below the center line of the regulating roller 203. This configuration can further enhance the above-mentioned effects. (Here, the first position 237 and the second position 238 are provided in a region below the center line of the regulating roller 203 and above the center of the rotation shaft 214 of the first conveying screw 204 in the vertical direction, and it can also be said that the second position 238 is provided above the first position 237.)

[0052] Furthermore, a first side wall 234 and a second side wall 235 having flat surfaces extending upward so as to face each other are provided at an end of first semi-cylindrical wall 231 formed on lower housing 212 opposite connecting partition wall 233, and at an end of second semi-cylindrical wall 232 formed on lower housing 212 opposite connecting partition wall 233. The extending direction of the flat surfaces (the direction of arrow K in FIG. 5) is configured to intersect with imaginary extension line L and the vertical direction (the direction of arrow V in FIG. 5).

[0053] Here, the upper housing 211 and the lower housing 212 that constitute the developing unit 144 have complex shapes and are generally made of resin. Therefore, they are often manufactured by injection molding, in which molten resin is poured into a mold. In this embodiment, the first semi-cylindrical wall 231, the second semi-cylindrical wall 232, the first side wall 234, and the second side wall 235 provided on the lower housing 212 are formed so that the extension direction (upward) of the flat portions of the first side wall 234 and the second side wall 235 is open. Furthermore, a virtual extension line L connecting a first position 237 and a second position 238 of a guide portion 236 formed on a connecting partition wall 233 provided to connect the first semi-cylindrical wall 231 and the second semi-cylindrical wall 232 passes below the center O of the regulating roller 203. Therefore, when molding the lower housing 212, a mold for forming the first semi-cylindrical wall 231, the second semi-cylindrical wall 232, and the guide portion 236 can be pulled in the direction of arrow K. This allows guide portion 236 to be formed integrally with lower housing 212 when molding it. In other words, guide portion 236 can be formed without being provided as a separate member, which makes it possible to reduce the number of parts and manufacturing costs.

[0054] Furthermore, the first position 237 of the guide portion 236 is provided above the first conveying screw 204, more specifically above the center of the rotation shaft 214. Furthermore, the end of the second semi-cylindrical wall 232 on the connecting partition wall 233 side is configured to cover a portion of the first conveying screw 204 in a plan view (when the first conveying screw 204 is viewed from above). With this configuration, it is possible to prevent an excessive amount of developer from being built up from the first conveying screw 204 onto the developing roller 202. Furthermore, it is possible to reliably return the developer that falls without passing through the gap between the regulating roller 202 and the sleeve of the developing roller 202 to the first conveying screw 204.

[0055] As described above, the first conveying screw 204 has a rotating shaft 214 and a helical blade 215 formed on the outer periphery of the rotating shaft 214. The helical blade 215 is configured to convey the developer in a predetermined direction (arrow E1) while pushing the developer upward from a vertically downward direction (the direction of arrow Q indicating the supply direction of the developer) toward the first position when rotated around the rotating shaft 214. In other words, the rotation direction of the rotating shaft 214 and the twist direction of the helical blade 215 are determined so that the side that pushes the developer upward by the helical blade 215 is the side of the regulating roller 203. For example, the rotating shaft 214 rotates in the direction indicated by arrow R2 in FIG. 5. This allows the developer conveyed by the first conveying screw 204 to be guided to the developing roller 202 via the guide portion 236. In particular, by configuring the end of the connecting partition wall side 233 of the second semi-cylindrical wall 232 to cover a portion of the first conveying screw 204 in a planar view, it is possible to effectively prevent an excessive amount of developer being supplied to the developing roller 202, which would otherwise clog the gap between the sleeve surface of the developing roller 202 and the regulating roller 203.

[0056] As described above, according to developing unit 144 of the present embodiment, guide portion 236 can be formed integrally with lower housing 212 that constitutes developing tank 201. This eliminates the need to manufacture guide portion 236 as a separate body, thereby reducing manufacturing costs.

[0057] The present invention is not limited to the above-described embodiments and can be modified, and the above configurations can be replaced with substantially the same configurations, configurations that achieve the same effects, or configurations that can achieve the same purpose. [Explanation of symbols]

[0058] 1. Image forming device 10 Printing device 60 Fixing device 144 Development unit 201 Developer tank 202 developing roller, 203 Regulating roller 204 First conveying screw 205 Second conveying screw 233 Connecting Partition Wall 236 Guide section 237 1st position 238 2nd position L Virtual extension line

Claims

1. a storage chamber for storing a developer containing toner; a developer carrier that carries the developer on its surface and rotates in a predetermined direction; a supply member disposed below the developer carrier and supplying the developer to a surface of the developer carrier; a layer regulating member provided downstream of the supply member in the rotation direction of the developer carrier, the layer regulating member having a cylindrical portion that regulates the layer thickness of the developer supplied onto the developer carrier, the developer carrying member, the supply member, and the layer regulating member are accommodated in the accommodation chamber; a connecting partition wall having a guide portion for guiding the developer formed between the supply member and the regulating member; The developing device is characterized in that the guide portion is formed so that an imaginary extension line connecting a first position, which is the end portion on the supply member side, and a second position, which is the end portion on the regulating member side, passes below the center line of the cylindrical portion of the regulating member.

2. the accommodation chamber has a first semi-cylindrical wall having a semi-cylindrical shape that forms a first space in which the layer regulating member is accommodated, and a second semi-cylindrical wall having a semi-cylindrical shape that forms a second space in which the supply member is accommodated, and the connecting partition wall is provided between the first space and the second space so as to connect the first semi-cylindrical wall and the second semi-cylindrical wall, a first side wall and a second side wall having planar portions extending upward so as to face each other are provided at an end of the first semi-cylindrical wall opposite to the connecting partition wall and an end of the second semi-cylindrical wall opposite to the connecting partition wall, 2. The developing device according to claim 1, wherein the extending direction of said flat surface portion intersects with said imaginary extension line and the vertical direction.

3. the first position of the guide portion is provided above the supply member, 3. The developing device according to claim 2, wherein an end of the second semi-cylindrical wall on the connecting partition wall side is configured to cover a part of the conveying member in a plan view.

4. the supply member has a rotating shaft and a spiral blade formed on the outer periphery of the rotating shaft, 2. The developing device according to claim 1, wherein the spiral blade is configured to transport the developer in a predetermined transport direction while pushing the developer upward from below toward the first position when the supply member is rotated around the rotation axis.

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

Images