JP6659177B2 - Developing device, developer container, process cartridge and image forming apparatus - Google Patents

Description

  The present invention relates to a developing device, a developer container, and a process cartridge used in an image forming apparatus.

  2. Description of the Related Art An electrophotographic image forming apparatus (hereinafter, referred to as an “image forming apparatus”) forms an image on a recording material using an electrophotographic image forming method. Examples of the image forming apparatus include a copying machine, a facsimile machine, a printer such as a laser beam printer, an LED (Light Emitting Diode) printer, and a multifunction machine (multifunction printer) thereof.

  The developing device develops an electrostatic latent image formed on an electrophotographic photosensitive member (hereinafter, referred to as “photosensitive member”) using a developer in an electrophotographic image forming process to form a visible image. In the process cartridge, at least as an image forming process means acting on the photosensitive member, the developing device is integrally formed as a cartridge, and is detachably mountable to a main body of the image forming device.

  2. Description of the Related Art In an image forming apparatus such as a printer using an electrophotographic image forming process, first, a photoconductor as an image carrier is uniformly charged. Next, an electrostatic latent image is formed on the photoconductor by selectively exposing the photoconductor. Next, a toner serving as a developer is supplied to the electrostatic latent image, developed as a toner image and visualized, and the toner image is transferred to a recording material such as paper or a plastic sheet. Then, the toner image transferred to the recording material is heated and pressed, and is thermally fixed to the recording material to record an image.

  An image forming apparatus using an electrophotographic image forming method generally requires replenishment of a developer and maintenance of various image forming process units. It is necessary to facilitate the work of replenishing the developer and the maintenance of various process means. To this end, a process cartridge (hereinafter, referred to as a “cartridge”) in which a photoconductor, a charging unit, a developing unit, a cleaning unit, and the like are integrally formed as a cartridge is configured to be detachable from the image forming apparatus main body. According to such a process cartridge system, the maintenance of the apparatus can be performed by the user himself in the form of replacing the cartridge. Therefore, operability can be improved.

  Further, a color image forming apparatus that forms a color image using a plurality of color developers has been widely used. As a color image forming apparatus, a photoconductor corresponding to each of the image forming operations using the developers of a plurality of colors is arranged in a line along the surface movement direction of the transfer target body on which the toner image is transferred, so-called, An in-line type image forming apparatus is known. In some in-line type color image forming apparatuses, a plurality of photoconductors are arranged in a line in a direction (for example, a horizontal direction) crossing a vertical direction (gravity direction). The in-line method is preferable in that it can easily meet demands such as an increase in image forming speed and development to a multifunction printer.

  As an in-line type image forming apparatus, as in Patent Document 1, a plurality of photoconductors are arranged below an intermediate transfer member as a transfer target or a recording material carrier that conveys a recording material as a transfer target. There is something. When the photoconductor is disposed below the intermediate transfer body and the recording material carrier, the intermediate transfer body and the recording material carrier are sandwiched between the photoconductor and the fixing device in the image forming apparatus main body. . As a result, the fixing device serving as a heat source and the cartridge can be arranged at positions separated from each other. Therefore, there is an advantage that the cartridge is hardly affected by heat from the fixing device.

  On the other hand, as a developing method of the developing device, generally, a contact developing method in which development is performed in a state where the developer carrier and the photoconductor are in contact with each other, or a predetermined interval is provided between the developer carrier and the photoconductor. There is a non-contact development method in which development is performed in a state where the image is developed. Further, as a method of supplying the developer to the developer carrying member, an opening communicating between the two chambers from a developer accommodating chamber containing the developer to a developing chamber provided with the developer carrying member is provided by using a conveying member. There is a method of supplying the developer through the section.

  When the photoconductor is disposed below the intermediate transfer member or the recording material carrier, it is necessary to transport the developer against the gravity in the developing device. In Patent Document 1, as a means for transporting the developer to a developing chamber disposed above the developer accommodating chamber, a flexible sheet member is provided at the tip of a rotatable stirring member for stirring the developer. A transport member is provided. Further, a receiving member for temporarily storing the developer is disposed below the developer carrier, and a flexible scraper is attached to a tip of the receiving member. The developer is transported to the chamber.

JP-A-2003-173083

  In such a configuration, if the toner supply to the developing chamber can be performed only by a small amount, when a high-density image is output, the toner supply is insufficient, so that the developing chamber needs to be enlarged in advance.

  An object of the present invention is to solve the above-described problems, and an object of the present invention is to provide a developing device and a developer container that can suppress the developer from dropping from a conveying member when conveying the developer against gravity. Is provided.

  A typical configuration according to the present invention for achieving the above object is as follows.

A developing chamber provided with a developer carrier, a housing chamber for housing the developer, and a partition for partitioning the developing chamber and the housing chamber, wherein an opening communicating the developing chamber with the housing chamber is provided. A frame provided with a partition wall, a stirring member for stirring the developer inside the storage chamber, and a shaft member rotatably supported inside the storage chamber, wherein the gravity of the opening is A shaft member having a mounting portion to which the stirring member is attached, and a transport member for transporting the developer inside the storage chamber, wherein the transport member forms the storage chamber. A fixing portion fixed to an inner wall of the frame, and a displacement portion movable with respect to the opening, wherein the fixing portion is fixed to the partition, and the displacement portion is provided between the opening and the shaft member. At the opening, by contacting the stirring member. The gravity direction lower side, and moves toward the opening, wherein Ri is constructed us to convey the developer to the developing chamber through the opening, in the direction perpendicular to the axis of rotation of said shaft member, said rotating A distance between an axis and the attachment portion is shorter than a shortest distance between the attachment portion and the inner wall, and the rotation axis is the displacement portion around a boundary point between the fixed portion and the displacement portion. Is located inside an imaginary circle passing through the tip of the developing device.

Further, a first chamber, a second chamber for storing a developer, and a partition for partitioning the first chamber and the second chamber, wherein an opening communicating the first chamber and the second chamber is provided. A frame provided with a partition wall, a stirring member for stirring the developer inside the second chamber, and a shaft member rotatably supported inside the second chamber, wherein the opening A shaft member having a mounting portion to which the stirring member is attached, and a conveying member for conveying the developer inside the second chamber, wherein the conveying member is provided in the second chamber. A fixed portion fixed to the inner wall of the frame body, and a displacement portion movable with respect to the opening, the fixed portion is fixed to the partition, the displacement portion, the opening and the It is located between the shaft members, and comes into contact with the stirring member, so that the opening is located below the opening in the direction of gravity. The move toward the opening, Made up to convey the developer to the first chamber through the opening, in a direction perpendicular to the rotational axis of the shaft member, the attachment and the axis of rotation The distance between the parts is shorter than the shortest distance between the mounting part and the inner wall, and the rotation axis passes through the tip of the displacement part centering on the boundary point between the fixed part and the displacement part. A developer container, which is located inside a virtual circle.

  ADVANTAGE OF THE INVENTION According to this invention, when a developer is conveyed against gravity, the fall of a developer from a conveyance member can be suppressed.

FIG. 1 is an explanatory cross-sectional view illustrating a configuration of an image forming apparatus according to the present invention. FIG. 2 is an explanatory cross-sectional view illustrating a configuration of a process cartridge according to the present invention. FIG. 3 is an explanatory cross-sectional view illustrating a configuration of a toner conveying member that conveys toner in the developing device according to the present invention. FIG. 4 is an explanatory cross-sectional view illustrating a configuration of a transport sheet having one end fixed to a lower surface of a bottom wall of a developing chamber in a toner storage chamber. FIG. 3 is an explanatory cross-sectional view illustrating a configuration of a transport sheet and a shaft member. FIGS. 3A and 3B are cross-sectional explanatory diagrams illustrating a toner conveying operation in a toner storage chamber. FIGS. 3A and 3B are cross-sectional explanatory diagrams illustrating a toner conveying operation in a toner storage chamber. FIG. 9 is an explanatory cross-sectional view illustrating a configuration of a modified example of the developing device according to the present invention. FIG. 3 is an explanatory cross-sectional view illustrating a configuration of a space for temporarily storing a developer on a transport sheet of the developing device according to the present invention. FIG. 5 is an explanatory cross-sectional view illustrating a toner conveying operation in the toner storage chamber. FIG. 3 is an explanatory cross-sectional view illustrating an example of the arrangement of a transport sheet and a shaft member according to the present invention.

  One embodiment of a developing device, a process cartridge, and an image forming apparatus according to the present invention will be specifically described with reference to the drawings. However, the present invention is not limited to the functions, materials, shapes, relative arrangements, and the like of the components described in the following embodiments.

<Image forming apparatus>
First, the configuration of the image forming apparatus 100 will be described with reference to FIG. FIG. 1 is an explanatory cross-sectional view illustrating a configuration of an image forming apparatus 100 according to the present invention. The image forming apparatus 100 shown in FIG. 1 is an example of an image forming apparatus using an electrophotographic method.

  The image forming apparatus 100 shown in FIG. 1 is configured in an inline system in which photosensitive drums 1Y, 1M, 1C, and 1K of respective colors of yellow Y, magenta M, cyan C, and black K as a plurality of image carriers are arranged in a line. You. Further, it is an example of a full-color laser beam printer employing an intermediate transfer system having an intermediate transfer belt 5 as an intermediate transfer member.

  The image forming apparatus 100 can form a full-color image on a recording material 12 such as paper, a plastic sheet, or cloth using a developer of each color according to image information. The image information is input to the main body of the image forming apparatus 100 from an image reading apparatus connected to the main body of the image forming apparatus 100 or a host device such as a personal computer communicably connected to the main body of the image forming apparatus 100.

  The image forming apparatus 100 includes, as the plurality of image forming units 23, image forming units 23Y, 23M, 23C, and 23K of respective colors of yellow Y, magenta M, cyan C, and black K, respectively. The configuration and operation of the image forming unit 23 for each color are substantially the same except that the color of the image to be formed is different. For convenience of explanation, the image forming units 23Y, 23M, 23C, and 23K may be used as a representative for description. The same applies to each image forming process means. In the present embodiment, the image forming units 23 are arranged in a line in a direction intersecting the vertical direction (the vertical direction in FIG. 1).

  The image forming apparatus 100 has, as a plurality of image carriers, a photosensitive drum 1 composed of four drum-type electrophotographic photosensitive members arranged side by side in a direction intersecting a vertical direction (vertical direction in FIG. 1). Each photosensitive drum 1 is rotationally driven in the direction of arrow A in FIG. 1 by a driving unit (drive source) not shown. Around the photosensitive drum 1, there are provided a charging roller 2 as charging means, a laser scanner unit 3 as exposure means, a developing device 4 as developing means, and a cleaning blade 6 as cleaning means.

  Further, an intermediate transfer belt 5 is provided to face each photosensitive drum 1. The intermediate transfer belt 5 is supported by a driving roller 51, a secondary transfer facing roller 52, and a driven roller 53 so as to be rotatable in the direction of arrow B in FIG. On the inner peripheral surface side of the intermediate transfer belt 5, a primary transfer roller 8 serving as a primary transfer unit facing each photosensitive drum 1 with the intermediate transfer belt 5 interposed is provided.

  The charging roller 2 uniformly charges the surface of the photosensitive drum 1. The uniformly charged surface of the photosensitive drum 1 is irradiated with a laser beam 3a based on image information emitted from the laser scanner unit 3. As a result, an electrostatic latent image is formed on the surface of the photosensitive drum 1.

  Toner 22 (developer) is supplied from the developing device 4 to the electrostatic latent image formed on the surface of the photosensitive drum 1. Thereby, the electrostatic latent image formed on the surface of the photosensitive drum 1 is developed as a toner image. The toner image formed on the surface of the photosensitive drum 1 is primarily transferred onto the outer peripheral surface of the intermediate transfer belt 5 by the primary transfer roller 8. The transfer residual toner remaining on the surface of the photosensitive drum 1 after the primary transfer is scraped off by the cleaning blade 6 and collected in the removed toner chamber 14a.

  The photosensitive drum 1 is provided in the following order in the rotation direction indicated by the arrow A in FIG. The charging position by the charging roller 2, the exposure position by the laser scanner unit 3, the developing position by the developing device 4, the primary transfer position to the intermediate transfer belt 5, and the cleaning position by the cleaning blade 6 are provided in this order.

  The developing device 4 of the present embodiment contains a non-magnetic one-component developer as a developer. The developing device 4 of this embodiment performs reversal development by bringing a developing roller 17 as a developer carrier into contact with the photosensitive drum 1. That is, the developing device 4 of the present embodiment has the same polarity as the charged polarity of the photosensitive drum 1 (in the present embodiment, the negative polarity in the portion where the charge is attenuated by exposing the surface of the photosensitive drum 1 (image portion, exposed portion)). 2), the charged toner 22 is attached. Thereby, the electrostatic latent image on the surface of the photosensitive drum 1 is developed as a toner image.

  The photosensitive drum 1 of the present embodiment, the charging roller 2 as an image forming process unit acting on the photosensitive drum 1, the developing device 4, and the cleaning blade 6 are integrally formed as a cartridge to form a process cartridge 7. The process cartridge 7 is configured to be detachable from the main body of the image forming apparatus 100 via mounting means such as a mounting guide (not shown) and a positioning member provided on the main body of the image forming apparatus 100.

  In the present embodiment, the process cartridges 7 of the respective colors have the same shape, and the toners 22 of the respective colors of yellow Y, magenta M, cyan C, and black K are contained in the developing device 4 of the process cartridge 7 of each color. Is housed. In the present embodiment, an example of a process cartridge 7 in which the photosensitive drum 1 and the developing device 4 are integrally provided will be described. In addition, the present invention can be applied to a case where the developing device 4 is configured as a developing cartridge that is detachable from the main body of the image forming apparatus 100 alone.

  The outer peripheral surface of the intermediate transfer belt 5 formed of an endless belt as an intermediate transfer member contacts the surfaces of all the photosensitive drums 1 and rotates in the direction of arrow B in FIG. The intermediate transfer belt 5 is stretched around a drive roller 51, a secondary transfer opposing roller 52, and a driven roller 53 serving as a plurality of support members.

  On the inner peripheral surface side of the intermediate transfer belt 5, four primary transfer rollers 8 as primary transfer means are arranged side by side so as to face the respective photosensitive drums 1. The primary transfer roller 8 presses the intermediate transfer belt 5 toward the surface of the photosensitive drum 1 by urging means (not shown). As a result, a primary transfer nip portion N1 where the outer peripheral surface of the intermediate transfer belt 5 and the surface of the photosensitive drum 1 are in contact is formed.

  From the primary transfer bias power supply (high-voltage power supply) as a primary transfer bias applying unit (not shown), the polarity (positive in this embodiment) opposite to the normal charging polarity (negative in this embodiment) of the toner 22 is applied to the primary transfer roller 8. Is applied. As a result, the toner images on the surface of each photosensitive drum 1 are sequentially primary-transferred and superimposed on the outer peripheral surface of the intermediate transfer belt 5.

  At a position facing the secondary transfer opposing roller 52 on the outer peripheral surface side of the intermediate transfer belt 5, a secondary transfer roller 9 as secondary transfer means is provided. The secondary transfer roller 9 is pressed against the secondary transfer opposing roller 52 by an urging means (not shown) via the intermediate transfer belt 5. As a result, a secondary transfer nip N2 where the outer peripheral surface of the intermediate transfer belt 5 and the secondary transfer roller 9 are in contact is formed.

  On the other hand, the recording material 12 accommodated in the feeding cassette 24 is fed out by a feeding roller 25, separated by a separating member 26, and fed one by one. After that, the recording material 12 is nipped and conveyed by the conveying roller 27, and the leading end thereof is applied to the nip portion of the registration roller 28 which is stopped, thereby correcting the skew.

  Thereafter, the registration roller 28 is rotated in synchronization with the timing at which the toner image on the outer peripheral surface of the intermediate transfer belt 5 reaches the secondary transfer nip portion N2, and the recording material 12 is nipped and conveyed by the registration roller 28 to form the secondary transfer nip. The sheet is transported to the section N2.

  From the secondary transfer bias power supply (high-voltage power supply) as a secondary transfer bias applying unit (not shown), the polarity (in the present embodiment) of the toner 22 to the secondary transfer roller 9 is opposite to the normal charge polarity (negative in this embodiment). (Positive polarity) secondary transfer bias is applied. As a result, the toner image on the outer peripheral surface of the intermediate transfer belt 5 is secondarily transferred to the recording material 12 at the secondary transfer nip N2. Each primary transfer roller 8 and secondary transfer roller 9 have the same configuration.

  During image formation, first, the surface of the photosensitive drum 1 is uniformly charged by the charging roller 2. Next, the uniformly charged surface of the photosensitive drum 1 is scanned and exposed by a laser beam 3a corresponding to the image information emitted from the laser scanner unit 3, and an electrostatic latent image corresponding to the image information is formed on the surface of the photosensitive drum 1. Is formed.

  Next, the electrostatic latent image formed on the surface of the photosensitive drum 1 is developed by the developing device 4 as a toner image. The toner image formed on the surface of the photosensitive drum 1 is primarily transferred onto the outer peripheral surface of the intermediate transfer belt 5 by the action of the primary transfer roller 8.

  When forming a full-color image, the above-described image forming process is sequentially performed in the image forming units 23 for each color. Then, the toner images of the respective colors are sequentially primary-transferred onto the outer peripheral surface of the intermediate transfer belt 5 and superimposed. Thereafter, the recording material 12 is conveyed to the secondary transfer nip N2 in synchronization with the rotational movement of the intermediate transfer belt 5 in the direction of arrow B in FIG. By the action of the secondary transfer roller 9 which is in contact with the outer peripheral surface of the intermediate transfer belt 5 via the recording material 12, the four color toner images on the outer peripheral surface of the intermediate transfer belt 5 are collectively collected on the recording material 12. Is secondarily transcribed.

  The recording material 12 to which the toner image has been transferred is conveyed to a fixing device 10 as a fixing unit. In the process of being nipped and conveyed by a fixing roller and a pressure roller provided in the fixing device 10, the toner image is heated and pressed to be melted by heat, and is thermally fixed to the recording material 12. Thereafter, the recording material 12 is nipped and conveyed by a discharge roller 29 and discharged onto a discharge tray 33 provided outside the image forming apparatus 100.

  The primary transfer residual toner remaining on the surface of the photosensitive drum 1 after the primary transfer is removed by the cleaning blade 6 and collected in the removed toner chamber 14a. On the other hand, the secondary transfer residual toner remaining on the outer peripheral surface of the intermediate transfer belt 5 after the secondary transfer is scraped and removed by a cleaning blade 11a provided in a cleaning device 11 serving as a cleaning unit. The image forming apparatus 100 can also form a single-color or multi-color image using only the desired single or plural (but not all) image forming units 23.

<Process cartridge>
Next, the configuration of the process cartridge 7 mounted on the image forming apparatus 100 will be described with reference to FIG. FIG. 2 is an explanatory sectional view showing the configuration of the process cartridge 7 according to the present invention. In the present embodiment, the configuration and operation of the process cartridge 7 for each color are substantially the same except for the type (color) of the developer contained. The process cartridge 7 illustrated in FIG. 2 includes a photosensitive unit 13 including the photosensitive drum 1 and the like, and a developing device 4 as a developing unit including the developing roller 17 and the like. In the following description, unless otherwise specified, the cross section refers to a cross section in a direction orthogonal to an axial direction of a shaft member 30 described later. The cross section will be described as viewed from the axial direction of the shaft member 30.

<Photoconductor unit>
The photoconductor unit 13 shown in FIG. 1 has a cleaning frame 14 as a frame for supporting various elements. The photosensitive drum 1 is rotatably provided on the cleaning frame 14 via a bearing (not shown). The photosensitive drum 1 is rotationally driven by a motor as a driving unit (drive source) (not shown), and is rotationally driven in the direction of arrow A in FIG. 2 in accordance with an image forming operation.

  The photoconductor unit 13 is provided with a charging roller 2 and a cleaning blade 6 so as to be in contact with the surface of the photoconductor drum 1. In the cleaning frame 14, there is provided a removed toner chamber 14a for accommodating the transfer residual toner removed from the surface of the photosensitive drum 1 by the cleaning blade 6. The transfer residual toner removed from the surface of the photosensitive drum 1 by the cleaning blade 6 falls and is stored in the removed toner chamber 14a.

  The cleaning frame 14 is provided with a bearing 15 that rotatably supports the charging roller 2. The bearing 15 is provided to be movable in the direction of arrow C in FIG. 2 along a straight line passing through the rotation center of the charging roller 2 and the rotation center of the photosensitive drum 1. The rotating shaft 2 a of the charging roller 2 is rotatably supported by a bearing 15. The bearing 15 is urged toward the photosensitive drum 1 by a pressure spring 16 as urging means.

<Developing device>
The developing device 4 serving as a developing unit has a developing frame 18 as a frame that supports various elements in the developing device 4. In the developing device 4, a developing chamber 18a (first chamber) in which a developing roller 17 (developer carrier) is provided by a developing frame 18 and a housing chamber 18b (second chamber) for storing toner 22 (developer). Are formed. The longitudinal direction of the developing frame 18 is provided along the longitudinal direction of the developing roller 17 and the supply roller 20 (the direction of the rotating shafts 17a and 20a). In the present embodiment, a portion of the developing device 4 including the developing frame 18 and a transport sheet 32, a stirring member 31, and a shaft member 30, which will be described later, is referred to as a developer container.

  FIG. 2 shows a posture in which the process cartridge 7 is mounted on the main body of the image forming apparatus 100. In the posture state shown in FIG. 2, the developing chamber 18a is arranged above the accommodation chamber 18b in the direction of gravity. The developing chamber 18a and the storage chamber 18b are partitioned by a partition wall 19 having a substantially L-shaped cross section.

  The partition wall 19 includes a side wall 19a provided at an angle θ (> 0) with respect to the horizontal line 35 shown in FIG. 3, and a bottom wall 19b forming a bottom surface of the developing chamber 18a. The side wall 19a is provided with an opening 19c formed of a through hole communicating the developing chamber 18a and the storage chamber 18b. The developing frame 18 (frame) includes a developing chamber 18 a (first chamber), a housing chamber 18 b (second chamber), and a partition wall 19.

  A shaft member 30 rotatably supported by the developing frame 18 is provided in the housing chamber 18b (inside the housing chamber or inside the second chamber). As shown in FIG. 2, the shaft member 30 is located below the opening 19c in the direction of gravity. The shaft member 30 is provided with a flexible stirring member 31 for stirring the toner 22 (developer) in the storage chamber 18b (inside the storage chamber). As shown in FIG. 2, the stirring member 31 is attached to the attachment portion 30 a of the shaft member 30. The stirring member 31 rotates in the direction of arrow F in FIG.

<Transportation member>
Below the opening 19c provided in the side wall 19a in the direction of gravity (downward in FIG. 2), a flexible member for transporting the toner 22 (developer) in the storage chamber 18b (in the storage chamber or in the second chamber). A transport sheet 32 serving as a transport member having a property is provided. The conveyance sheet 32 (conveyance member) has a housing chamber formed at one end side in a direction (left-right direction in FIG. 2) orthogonal to the rotation axis direction of the shaft member 30 by a lower surface of a bottom wall 19b serving as a frame forming the housing chamber 18b. It is fixed to the surface 19b2. This portion is referred to as a fixing portion 321. That is, the fixing portion 321 is a portion fixed to the inner wall of the developing frame 18 (frame) that forms the storage chamber 18b.

  In the present embodiment, the bottom wall 19b of the partition wall 19 is a part of the inner wall forming the accommodation room 18b. Note that the transport sheet 32 may be fixed to a portion other than the bottom wall 19b. The transport sheet 32 is configured as a displacement unit 322 that can move on the other end side. The displacement section 322 is movable with respect to the opening 19c. As described above, the transport sheet 32 (transport member) is configured to include the fixed portion 321 and the displacement portion 322.

  As shown in FIGS. 7A and 7B, the transport sheet 32 has a transport surface 32 a opposite to a contact surface 32 b that is in contact with the stirring member 31 and is fixed to the bottom wall 19 b of the partition wall 19. Is done. The displacement portion 322 of the transport sheet 32 (transport member) is located between the opening 19c and the shaft member 30, and can move toward the opening 19c from below the opening 19c in the direction of gravity by abutting on the stirring member 31. It is. The angle formed between the side wall 19a of the partition wall 19 provided with the opening 19c and the horizontal direction shown in the left and right directions in FIGS. 7A and 7B is such that the conveying sheet 32 (conveying member) is moved by the stirring member 31. A positive value in the direction.

  Cooperation between the stirring member 31 that rotates integrally with the shaft member 30 in the direction of arrow F in FIG. 2 and the transport sheet 32 in which the fixing portion 321 is fixedly supported on the storage chamber surface 19b2 formed by the lower surface of the bottom wall 19b. Thus, the toner 22 is transported from the storage chamber 18b into the developing chamber 18a.

  The side wall 19a of the partition wall 19 is provided with an opening 19c which is located above the shaft member 30 in the direction of gravity (upward in FIG. 2) and is formed of a through-hole communicating the developing chamber 18a and the housing chamber 18b. In other words, the shaft member 30 is arranged below the opening 19c in the direction of gravity. The opening 19c is provided above the bottom wall 19b. This can prevent the toner 22 transported from the storage chamber 18b into the developing chamber 18a via the opening 19c from returning to the storage chamber 18b via the opening 19c.

  As shown in FIG. 2, in a posture in which the process cartridge 7 is mounted on the main body of the image forming apparatus 100, an opening 19c for communicating the developing chamber 18a with the storage chamber 18b is provided above the storage chamber 18b in the direction of gravity. ing. The developing chamber 18a is provided with a developing roller 17 as a developer carrier that rotates in the direction of arrow D in FIG. 2 in contact with the surface of the photosensitive drum 1. The developing roller 17 and the photosensitive drum 1 rotate so that their surfaces move in the same direction (in the present embodiment, the direction from the bottom to the top in FIG. 2) at the opposing portion (contact portion).

  This embodiment is an example in which the developing roller 17 is provided in contact with the surface of the photosensitive drum 1. Alternatively, the developing roller 17 may be arranged so as to face the surface of the photosensitive drum 1 and to be closely spaced at a predetermined interval. The developing chamber 18a is provided with a supply roller 20 as a developer supply member that rotates in the direction of arrow E in FIG. The supply roller 20 contacts the surface of the developing roller 17. In the present embodiment, the supply roller 20 and the developing roller 17 rotate so that their surfaces move in opposite directions at opposing portions (contact portions).

  The supply roller 20 supplies the toner 22 in the developing chamber 18 a onto the surface of the developing roller 17. Further, the toner 22 remaining on the surface of the developing roller 17 without being used for development is peeled off from the surface of the developing roller 17 and collected in the developing chamber 18a. The developing roller 17 and the supply roller 20 are rotatably supported at both ends of respective rotating shafts 17a and 20a via bearings (not shown) provided on the developing frame 18, respectively.

  The developing frame 18 of the developing device 4 supports a developing blade 21 as a developer regulating member that regulates the layer thickness of the toner 22 on the surface of the developing roller 17 supplied by the supply roller 20. The developing blade 21 contacts the surface of the developing roller 17.

  A shaft member 30 rotatably supported by the developing frame 18 is provided in the housing chamber 18b. The shaft member 30 is rotated in a direction indicated by an arrow F in FIG. 2 around a rotation center G (rotation axis) by transmitting a rotation driving force of a motor serving as a driving unit (drive source) (not shown) provided in the image forming apparatus 100. Driven.

  The shaft member 30 is provided substantially in parallel with the longitudinal direction (rotation axis direction) of the photosensitive drum 1, the developing roller 17, and the supply roller 20 over the entire longitudinal direction in the storage chamber 18b. One end of a stirring member 31 having flexibility is supported by the shaft member 30. One end of the stirring member 31 in a direction (rotational radius direction, short direction) substantially orthogonal to the longitudinal direction of the shaft member 30 (axial direction of the shaft member 30) is supported by the shaft member 30.

  The stirring member 31 stirs the toner 22 stored in the storage chamber 18b by rotating in the direction of arrow F in FIG. 2 around the shaft member 30. Also, as shown in FIG. 6B, the toner 22 scooped up on the stirring surface 31a of the stirring member 31 is transferred onto the conveying surface 32a of the conveying sheet 32 as shown in FIG. 7A. Further, as shown in FIG. 7B, the rotation of the stirring member 31 causes the stirring member 31 to transfer the transport sheet 32 to a boundary point between the fixed portion 321 and the displacement portion 322, which are fixed to the storage chamber surface 19b2 of the bottom wall 19b. Push around H in the counterclockwise direction in FIG. 7B. As a result, the toner 22 on the transport surface 32a of the transport sheet 32 is transported from the opening 19c into the developing chamber 18a.

  A fixing portion 321 on one end side of the flexible conveying sheet 32 is fixed and supported on a housing chamber surface 19b2 which is a lower surface of the bottom wall 19b of the developing chamber 18a on the housing chamber 18b side. Thereby, the fixing portion 321 on one end side of the transport sheet 32 in a direction (short direction) substantially orthogonal to the longitudinal direction of the side wall 19a is fixed to the housing chamber surface 19b2 serving as the lower surface of the bottom wall 19b of the developing chamber 18a. Further, the displacement portion 322 on the other end side is supported in a cantilever shape by its own rigidity so as to be movable.

  As shown in FIG. 7A, the toner 22 transported by the stirring member 31 is delivered to the transport sheet 32. Thereafter, as shown in FIG. 7B, the stirring member 31 is deformed toward the opening 19c by rotation. Thus, the toner 22 is transported from the opening 19c into the developing chamber 18a.

  As shown in FIG. 2, a pair of developing side plates 60 </ b> R and 60 </ b> L are provided at both ends in the longitudinal direction of the developing frame 18. Holes 60Ra, 60La are provided at one end of the development side plates 60R, 60L. On the other hand, a pair of shafts 61R and 61L are provided at both ends in the longitudinal direction of the cleaning frame 14. The shafts 61R, 61L provided on the cleaning frame 14 are slidably inserted into holes 60Ra, 60La provided on the developing frame 18. As a result, the developing frame 18 is swingably connected around the shafts 61R and 61L provided on the cleaning frame 14.

  During image formation, the developing device 4 is urged by urging means (not shown) to rotate about the shafts 61R and 61L in the direction of arrow J in FIG. As a result, the developing roller 17 provided in the developing device 4 comes into contact with the surface of the photosensitive drum 1 provided in the photosensitive unit 13.

<Transportation member>
Next, the configuration of the transport member in the developing device 4 will be described with reference to FIGS. FIG. 3 is an explanatory cross-sectional view illustrating a configuration of a transport member that transports the toner 22 in the developing device 4 according to the present invention. In the configuration of the developing device 4 or the process cartridge 7 which will be described below as a developing unit, the vertical direction, the vertical direction, and the horizontal direction are different in a normal use state in which the process cartridge 7 is mounted on the image forming apparatus 100 main body. Indicates the direction. The normal use state of the developing device 4 or the process cartridge 7 is a state in which the developing device 4 or the process cartridge 7 is properly mounted on the properly arranged image forming apparatus 100 main body and can be used for an image forming operation.

  As shown in FIG. 3, the developing chamber 18a and the housing chamber 18b formed by the developing frame 18 are separated by a partition wall 19 having a side wall 19a and a bottom wall 19b, and communicate with each other by an opening 19c provided in the side wall 19a. are doing. The opening 19c is desirably opened in the entire lengthwise direction along the rotation axis 17a of the developing roller 17 in the developing device 4. However, the opening 19c in the longitudinal direction of the opening 19c is so long as not to hinder the supply of the toner 22. A pillar (rib) may be provided in the middle.

  The angle θ formed between the side wall 19a provided with the opening 19c and the horizontal line 35 in the horizontal direction (the horizontal direction in FIG. 3) is set as follows. The direction in which the transport sheet 32 (transport member) is deformed by the stirring member 31 is considered. That is, the displacement portion 322 of the transport sheet 32 is pushed up by the stirring member 31 that rotates about the shaft member 30, and the displacement portion 322 is centered on the boundary point H between the fixed portion 321 and the displacement portion 322 of the transport sheet 32 in FIG. Is considered in the counterclockwise direction. A positive value (θ> 0) is set in that direction.

  The angle θ of the side wall 19 a with respect to the horizontal line 35 is configured to be larger than the angle of repose of the toner 22. The angle of repose is an angle of a slope that maintains stability without spontaneous collapse of the toner 22.

  As a result, the toner 22 conveyed from the storage chamber 18b into the developing chamber 18a can move in the direction of the developing roller 17 by its own weight. It is preferable that the angle θ of the side wall 19a with respect to the horizontal line 35 is 30 ° to 150 °. However, the angle θ is not limited to this range, but if the angle is smaller than this, the toner 22 may stagnate on the surface of the side wall 19a on the side of the developing chamber 18a depending on the fluidity of the toner 22. There is.

  The lower part of the side wall 19a is connected to the bottom wall 19b at the connection part P. In order to efficiently supply the toner 22 conveyed into the developing chamber 18 a to the developing roller 17, the bottom wall 19 b is provided over the entire length of the developing roller 17 so as not to return the toner 22 to the housing chamber 18 b. 18 are provided integrally.

  A shaft member 30 rotatably supported by the developing frame 18 is provided in the housing chamber 18b. The shaft member 30 is rotated in a direction indicated by an arrow F in FIG. 3 by transmitting a rotational driving force of a motor serving as a driving unit (drive source) (not shown) provided in the image forming apparatus 100.

  The shaft member 30 is provided over the entire area in the longitudinal direction of the storage chamber 18b substantially in parallel with the longitudinal direction (the rotation axis direction) of the photosensitive drum 1, the developing roller 17, and the supply roller 20. One end of a flexible stirring member 31 is fixedly provided on the shaft member 30. One end of the stirring member 31 in a direction substantially perpendicular to the longitudinal direction of the shaft member 30 (rotational radius direction, short direction) is fixed to the shaft member 30.

  The stirring member 31 conveys the toner between the shaft member 30 and the inner wall of the developing frame 18 forming the storage chamber 18b. Therefore, in order for the stirring member 31 to convey more toner, the distance between the stirring member 31 and the rotation center G (rotation axis) of the shaft member 30 is short, and the shaft member 30 and the storage chamber 18b are formed. The distance between the developing frame 18 and the inner wall of the developing frame 18 is preferably long.

  As shown in FIGS. 2 and 3, in the present embodiment, in the direction orthogonal to the rotation center G (rotation axis) of the shaft member 30, the position between the rotation center G (rotation axis) of the shaft member 30 and the mounting portion 30 a is set. Is considered. The distance L4 is shorter than the shortest distance L5 between the inner wall of the developing frame 18 forming the storage chamber 18b and the mounting portion 30a. The shortest distance L5 is the minimum value of the distance between the inner wall of the developing frame 18 forming the storage chamber 18b and the mounting portion 30a during one rotation of the shaft member 30.

  The distance L4 shown in FIG. 2 indicates the longest distance between the mounting portion 30a formed on one surface of the shaft member 30 having a square cross section and the rotation center G (rotation axis) of the shaft member 30. On the other hand, the shortest distance L5 indicates the shortest distance between the rotation trajectory 30c of the corner of the shaft member 30 and the inner wall of the developing frame 18 forming the storage chamber 18b. Further, the length of the stirring member 31 was set to be longer than the rotation diameter of the attachment portion 30a (the diameter of the rotation locus 30c of the corner of the shaft member 30).

  The stirring member 31 has a stirring surface 31a that is a surface on the downstream side in the rotation direction of the shaft member 30 as indicated by the arrow F in FIG. The stirring member 31 can be manufactured using a flexible resin sheet such as a polyester film, a polyphenylene sulfide film, and a polycarbonate film. The thickness of the stirring member 31 is preferably 50 μm to 250 μm. However, the material and thickness of the stirring member 31 need not be limited to these.

  The length L1 from the rotation center G of the shaft member 30 to the tip 31b of the stirring member 31 is considered. The length L1 corresponds to the maximum value of the radius of rotation of the stirring member 31 in a natural state where the stirring member 31 is not deformed.

  In addition, a linear distance L2 from the rotation center G of the shaft member 30 to the innermost wall 181a of the inner wall 181 of the storage chamber 18b in the direction of gravity is considered. In the present embodiment, the length L1 and the linear distance L2 satisfy a relationship expressed by the following equation (1).

[Equation 1]
L1> L2

  In the accommodation room 18b, one end of a flexible conveyance sheet 32 is fixed to an accommodation room surface 19b2 which is a lower surface of the bottom wall 19b of the developing room 18a. FIG. 4 is a cross-sectional explanatory view illustrating a configuration of the transport sheet 32 in which one end is fixed to a housing chamber surface 19b2 which is a lower surface of the bottom wall 19b of the developing chamber 18a in the housing chamber 18b. As shown in FIG. 4, the bottom wall 19b of the developing chamber 18a has a developing chamber surface 19b1 on the developing chamber 18a side and a housing chamber surface 19b2 on the housing chamber 18b side.

  The transport sheet 32 is provided over substantially the entire area in the longitudinal direction of the developing roller 17 (the direction of the rotation shaft 17a), similarly to the stirring member 31 shown in FIG. The transport sheet 32 has a transport surface 32 a facing the opening 19 c provided in the side wall 19 a shown in FIG. 3 and a contact surface 32 b facing the shaft member 30.

  The transporting sheet 32 has a fixing section 321 provided at one end (the left end in FIG. 4) in a direction substantially perpendicular to the longitudinal direction (the left and right direction in FIG. 4) and serves as a lower surface of the bottom wall 19b of the developing chamber 18a. It is fixed to the surface 19b2. The fixing portion 321 is formed such that the accommodation chamber surface 19b2 of the bottom wall 19b and the conveying surface 32a of the conveying sheet 32 substantially extend from the fixed end portion 32c to the connecting portion P between the side wall 19a and the bottom wall 19b in the longitudinal direction of the bottom wall 19b. It is desirable that the surfaces be adhered to each other.

  In the fixing portion 321 of the present embodiment, the accommodation room surface 19b2, which is the lower surface of the bottom wall 19b, and the fixing portion 321 of the transport sheet 32 are adhered by a double-sided adhesive tape (not shown). Alternatively, an adhesive or heat bonding or welding may be used, and there is no need to be limited to this. As shown in FIG. 4, the surface of the transport sheet 32 opposite to the surface with which the agitating member 31 contacts is fixed to the bottom wall 19b (the accommodation chamber surface 19b2). Accordingly, when the fixing portion 321 is deformed by the stirring member 31, it is possible to suppress a force that separates the fixing portion 321 from the developing frame 18.

  Next, the configuration of the transport sheet 32 and the shaft member 30 will be described with reference to FIG. FIG. 5 is an explanatory cross-sectional view illustrating the configuration of the transport sheet 32 and the shaft member 30 as viewed from the axial direction of the shaft member 30. A side opposite to the fixed end 32c of the transport sheet 32 shown in FIG. 5 is defined as a free end 32d. A region other than the fixed portion 321 including the free end 32d is configured to be movable as the displacement portion 322.

  As shown in FIG. 5, the rotation center G (rotation axis) of the shaft member 30 is defined by a boundary point H between the fixed portion 321 and the displacement portion 322 of the transport sheet 32 corresponding to the connection portion P between the side wall 19a and the bottom wall 19b. Are provided in a region Q of the radius of rotation of the displacement portion 322 (within the region of the radius of rotation). The rotation radius of the displacement portion 322 has a length L3 from the boundary point H to the free end 32d. The above-described region Q of the radius of gyration coincides with the virtual circle q centering on the boundary point H and passing through the tip (free end 32d) of the displacement portion 322. Therefore, the rotation center G (rotation axis) of the shaft member 30 is located inside (inside region) of the virtual circle q passing through the tip of the displacement portion 322 about the boundary point H.

  In a state in which the transport sheet 32 does not receive an external force from another (a state in which the transport sheet 32 does not come into contact with the stirring member 31), the free end portion 32d is located at a boundary point with respect to a vertical line m passing through the rotation center G of the shaft member 30. H is provided on the opposite side. The boundary point H is a boundary between the fixed portion 321 that cannot be deformed when the conveyance sheet 32 receives an external force from another, and the deformable displacement portion 322.

  The transport sheet 32 can be suitably manufactured using a flexible resin sheet such as a polyester film, a polyphenylene sulfide film, and a polycarbonate film. The transport sheet 32 and the stirring member 31 are both made of resin sheets. For this reason, it has the property of being easily bent by the stress due to external force.

  It is desirable that the transport sheet 32 has a property that is more flexible than the stirring member 31. If the same material is used, the thickness of the transport sheet 32 is made smaller than the thickness of the stirring member 31. If different materials are used, it is desirable to set the rigidity of the transport sheet 32 to be lower than the rigidity of the stirring member 31. The transport sheet 32 preferably has a thickness of 50 μm to 250 μm. It is desirable that the conveyance sheet 32 does not slack (the middle part does not slack) due to its own weight or the weight of the toner 22. The transport sheet 32 can be applied to materials other than the resin material.

<Toner transport operation>
Next, the operation of transporting the toner 22 by the stirring member 31 and the transport sheet 32 will be described with reference to FIGS. FIGS. 6, 7, and 10 are cross-sectional views illustrating the toner conveying operation in the storage chamber 18b. The stirring member 31 shown in FIG. 6A satisfies the relationship of the above equation (1). Therefore, the stirring member 31 can abut (contact) with the inner wall of the developing frame 18 inside the storage chamber 18b (inside the second chamber). The shaft member 30 rotates around the rotation center G in the counterclockwise direction in FIG. Accordingly, the stirring member 31 abuts on the inner wall 181 of the storage chamber 18b while rotating integrally with the shaft member 30, and bends with the rotation.

  Then, as shown in FIG. 6B, the stirring member 31 further rotates to scoop up the toner 22 stored in the storage chamber 18b onto the stirring surface 31a of the stirring member 31. Then, as shown in FIG. 10, the stirring surface 31 a contacts the free end 32 d of the transport sheet 32. At this time, the stirring member 31 is in contact with the transport sheet 32 on a free end side (tip side) with respect to a portion supported by the shaft member 30. Next, as shown in FIG. 7A, the rotation of the stirring member 31 causes the stirring surface 31a of the stirring member 31 to contact at least one of the free end 32d of the conveying sheet 32 or the contact surface 32b, A transport space T composed of a closed space is temporarily formed in the accommodation room 18b.

  The transport space T shown in FIG. 7A is formed as a closed space by the inner wall 181 of the developing frame 18, the side wall 19 a, the transport surface 32 a of the transport sheet 32, and the stirring surface 31 a of the stirring member 31. By forming the transport space T in the upper portion of the storage chamber 18b, the toner 22 can be retained above the accumulation surface 221 of the toner 22 stored on the bottom surface 18b1 in the storage chamber 18b.

  Further, the toner 22 scooped up on the stirring surface 31a of the stirring member 31 is prevented from falling into the storage chamber 18b, and the toner 22 can be kept on the stirring surface 31a of the stirring member 31. At this time, the displacement portion 322 of the transport sheet 32 is deformed upward in FIG. 7A while sliding in contact with the stirring surface 31 a of the stirring member 31 that rotates integrally with the shaft member 30. As a result, the toner 22 on the stirring surface 31 a of the stirring member 31 is gradually transferred to the conveying surface 32 a of the conveying sheet 32.

  Further, when the stirring member 31 rotates, as shown in FIG. 7B, the displacement portion 322 of the transport sheet 32 is urged and pushed up by the stirring member 31, and moves toward the opening 19c provided in the side wall 19a. Deform. Due to this deformation, the toner 22 on the conveying surface 32a of the conveying sheet 32 is conveyed toward the opening 19c, and supplied into the developing chamber 18a through the opening 19c. That is, the displacement part 322 is movable with respect to the opening 19c. The displacement portion 322 is located between the opening 19c and the shaft member 30. The displacement portion 322 can move toward the opening 19c from a position below the opening 19c in the direction of gravity by abutting on the stirring member 31.

  As shown in FIG. 7A, a wedge-shaped portion V having a V-shaped cross section is formed between the side wall 19a and the transport surface 32a of the transport sheet 32. As shown in FIG. 7B, the displacement portion 322 of the transport sheet 32 is lifted by the rotation of the stirring member 31 that rotates integrally with the shaft member 30. At this time, the wedge-shaped portion V is deformed in a direction to reduce the width W. As a result, the toner 22 accumulated in the wedge-shaped portion V is extruded upward with the opening 19c of the side wall 19a. As a result, the toner 22 is transported from the opening 19c into the developing chamber 18a.

  Thereafter, the stirring member 31 further rotates around the shaft member 30 in the counterclockwise direction in FIG. 7B. Then, the stirring member 31 passes through the connection portion P between the side wall 19a and the bottom wall 19b, comes into a non-contact state with the transport sheet 32, and returns to the state shown in FIG. The toner 22 in the storage chamber 18b can be stably supplied into the developing chamber 18a by repeating the operation of transporting the toner 22 shown in FIGS.

  In the present embodiment, as shown in FIG. 5, the rotation center G of the shaft member 30 is defined as a radius of the length L3 of the displacement portion 322 about the boundary point H between the fixed portion 321 and the displacement portion 322 of the conveyance sheet 32. It is arranged in the area Q of the radius of gyration (inside the virtual circle q described above). In the present embodiment, the distance between the stirring member 31 and the rotation center G (rotation axis) of the shaft member 30 is short because the stirring member 31 conveys more toner 22. At this time, if the distance between the stirring member 31 and the rotation center G (rotation axis) of the shaft member 30 is long, the toner 22 drops from the stirring member 31 before being transferred from the stirring member 31 to the transport sheet 32. The amount of toner may increase.

  On the other hand, by arranging the rotation center G of the shaft member 30 as in the present embodiment, the case where the rotation center G of the shaft member 30 is outside the region Q of the rotation radius (outside the above-described virtual circle q) is described. In comparison, the conveying sheet 32 and the agitating member 31 abut early. That is, the configuration of the present embodiment can reduce the time from when the stirring member 31 starts scooping the toner 22 to when the conveying sheet 32 and the stirring member 31 come into contact with each other. That is, the amount of toner 22 falling from the gap between the transport sheet 32 and the shaft member 30 can be reduced. Therefore, it is possible to transfer more toner 22 while increasing the transport space T and suppressing the toner 22 from dropping.

  Further, by arranging the rotation center G of the shaft member 30 as in the present embodiment, the stirring member 31 that rotates in the direction indicated by the arrow F in FIG. The displacement portion 322 can be reliably contacted and pushed upward. Therefore, it is possible to prevent the toner 22 scooped up on the stirring surface 31a of the stirring member 31 from falling. Thereby, the toner 22 scooped up on the stirring surface 31a of the stirring member 31 rotating in the direction of arrow F in FIG. 5 around the rotation center G of the shaft member 30 can be stably delivered to the conveying surface 32a of the conveying sheet 32. Can be.

  As shown in FIG. 7, in the present embodiment, in the direction orthogonal to the rotation center G (rotation axis) of the shaft member 30, the rotation center G (rotation axis) of the shaft member 30 (Conveying member). Further, in a direction orthogonal to the rotation center G (rotation axis) of the shaft member 30, while the conveyance sheet 32 (conveyance member) is in contact (contact) with the stirring member 31, the mounting portion 30 a is in the opening 19 c. On the other hand, it is located on the leading end side of the transport sheet 32. In this way, the stirring member 31 can easily move the transport sheet 32 to the vicinity of the opening 19c.

  Here, consider a case where the rotation center G of the shaft member 30 is outside the region Q of the rotation radius (outside the above-described virtual circle q). In this case, depending on the position of the leading end of the transport sheet 32 and the contact state of the stirring member 31, the transport sheet 32 may be pushed down by the stirring member 31. That is, if the direction in which the transport sheet 32 is pushed up to supply the toner 22 from the opening 19c is set as the supply direction, the sheet may be pushed down in a direction opposite to the supply direction and turned up.

  On the other hand, in the configuration of the present embodiment, the displacement portion 322 of the transport sheet 32 can be moved in the above-described supply direction, and the occurrence of turning over can be suppressed. Further, even when the transport sheet 32 is lowered in the downward direction due to the weight of the toner 22 or the like, it can be received by the shaft member 30, so that the occurrence of the above-described turning can be suppressed.

  Here, another arrangement of the transport sheet 32 and the shaft member 30 will be described with reference to FIG. FIG. 11 is an explanatory cross-sectional view showing an example of the arrangement of the transport sheet 32 and the shaft member 30 according to the present invention.

  In the configuration illustrated in FIG. 5, the rotation center G of the shaft member 30 is a region having a rotation radius with the length L3 of the displacement portion 322 as a radius around the boundary point H between the fixed portion 321 and the displacement portion 322 of the transport sheet 32. Q (the inside of the virtual circle q described above). On the other hand, in the configuration shown in FIG. 11, the entire shaft member 30 is arranged in the region Q of the radius of rotation (inside the above-described virtual circle q). By doing so, the displacement portion 322 of the transport sheet 32 can be pushed up more reliably.

  6 and 7 can stably carry out the operation of transporting the toner 22, so that it is possible to increase the amount of toner that supplies the toner 22 in the storage chamber 18b into the developing chamber 18a per rotation of the stirring member 31. it can. Thus, the volume of the developing chamber 18a can be reduced, and the size of the developing device 4 can be reduced.

  In the present embodiment, first, as shown in FIG. 6B, the stirring member 31 rotates integrally with the shaft member 30 in the counterclockwise direction in FIG. 6B around the rotation center G of the shaft member 30. By doing so, the toner 22 in the storage chamber 18b is scooped up and stored on the stirring surface 31a. Thereafter, as shown in FIG. 7A, the stirring surface 31a of the stirring member 31 abuts on the lower surface of the displacement portion 322 of the conveying sheet 32 to form a conveying space T composed of a closed space. The toner 22 on the transfer sheet 32 is transferred to the transfer surface 32a of the transfer sheet 32.

  Thereby, the toner 22 is prevented from dropping into the storage chamber 18b while the toner 22 is being transported in the transport space T by the cooperation of the stirring member 31 and the transport sheet 32, and the toner 22 is transported stably. Can be. When the toner 22 in the storage chamber 18b is transported upward against the gravity, the path in which the toner 22 being transported falls by its own weight and returns to the storage chamber 18b is closed. As a result, the toner 22 in the storage chamber 18b can be stably transported upward against gravity.

<Modification>
FIG. 8 is an explanatory cross-sectional view illustrating a configuration of a modification of the developing device 114 according to the invention. As in the developing device 114 of the modified example shown in FIG. 8, a case is considered in which the tip end portion 31 b of the stirring member 31 has a rotation phase below the rotation center G of the shaft member 30. At this time, the transport sheet 132 is located below the opening 19c provided in the side wall 19a in the direction of gravity (downward in FIG. 8). The transport sheet 132 serving as a flexible transport member that transports the toner 22 (developer) can be brought into contact with the shaft member 30 or the stirring member 31 by at least one of its own restoring force or its own weight. It is good also as composition.

  According to the configuration of the developing device 114 of the modified example shown in FIG. 8, the toner 22 scooped up by the stirring surface 31a of the stirring member 31 rotating in the direction of arrow F in FIG. On the transport surface 132a. Before that, the transfer space T composed of a closed space can be formed.

  As a result, as shown in FIG. 6B, the toner 22 scooped up by the stirring surface 31 a of the stirring member 31 rotating counterclockwise in FIG. On the transfer surface 32a. Before that, the fall of the toner 22 into the storage chamber 18b can be further suppressed as compared with the case where the gap 34 is formed between the displacement portion 322 of the transport sheet 32 and the shaft member 30 or the stirring member 31. it can. This further increases the amount of toner that supplies the toner 22 in the storage chamber 18b into the developing chamber 18a per rotation of the stirring member 31.

  FIG. 9 is a cross-sectional explanatory view showing a configuration of a space 40 for temporarily storing the toner 22 (developer) on the transport sheet 32 of the developing device 4 according to the present invention. In the developing device 4 shown in FIG. 9, the fixing portion 321 of the transport sheet 32 is fixed to the storage chamber surface 19b2 of the bottom wall 19b provided below the opening 19c provided in the side wall 19a. On the other hand, the displacement portion 322 of the transport sheet 32 is provided so as to be movable toward the inside of the storage chamber 18b. The transport sheet 32 is made of a flexible resin sheet. Therefore, the rigidity of the transport sheet 32 can be set high by appropriately selecting the thickness and the material of the transport sheet 32.

  The transport sheet 32 (transport member) of the present embodiment forms a space 40 for temporarily storing the toner 22 (developer) between the transport sheet 32 and the side wall 19a (partition wall) provided with the opening 19c. A space 40 indicated by a grid line portion in FIG. 9 where the toner 22 can be temporarily deposited is formed on the conveying surface 32a of the conveying sheet 32. As shown in FIG. 7B, the displacement part 322 of the transport sheet 32 is pushed up by the stirring member 31 which rotates integrally with the shaft member 30 in the counterclockwise direction in FIG. 7B. Thereafter, the toner 22 on the transport surface 32a of the transport sheet 32 is transported toward the opening 19c provided in the side wall 19a.

  When the toner 22 is abundant in the developing chamber 18a, all of the toner 22 on the stirring surface 31a of the stirring member 31 and the conveying surface 32a of the conveying sheet 32 is not conveyed into the developing chamber 18a. As shown in FIG. 6A, the stirring member 31 rotating counterclockwise in FIG. 7B integrally with the shaft member 30 passes through the connecting portion P between the side wall 19a and the bottom wall 19b. The member 31 is not in contact with the transport sheet 32. Thereafter, a certain amount of the toner 22 falls from the conveying surface 32a of the conveying sheet 32 by its own weight and returns to the storage chamber 18b.

  At this time, the toner 22 can be temporarily deposited in the space 40 provided on the transport surface 32a of the transport sheet 32. Thus, the toner 22 can be temporarily accumulated in the space 40 provided above the accumulation surface 221 of the toner 22 accommodated in the accommodation chamber 18b.

  At this time, the toner 22 deposited in the space 40 exists above the toner 22 stored in the storage chamber 18b in the direction of gravity. Thereby, the toner 22 deposited in the space 40 is in a state of high potential energy. Thus, the mechanical energy required to lift the toner 22 accumulated on the bottom surface 18b1 in the storage chamber 18b to the opening 19c provided in the side wall 19a can be reduced by one step.

  Thus, the toner 22 can be transported upward with a small force. Accordingly, the rigidity of the stirring member 31 can be reduced, and a striking sound generated when the stirring member 31 rotating integrally with the shaft member 30 comes into contact with the developing frame 18 and the stirring member 31 It is possible to suppress the rubbing noise generated at the time of sliding contact with the contact member 18.

  Note that the displacement portion 322 of the transport sheet 132 contacts the shaft member 30 or the stirring member 31 as in the above-described modification shown in FIG. Even in such a configuration, a similar effect can be obtained by forming a space 40 indicated by a grid line portion in FIG. 9 in which the toner 22 can be temporarily deposited on the transport surface 132a of the transport sheet 132.

  As shown in FIG. 9, a wedge-shaped portion V is formed between the side wall 19a and the transport surface 32a of the transport sheet 32. The same effect can be obtained even when the toner amount of the toner 22 stored in the storage chamber 18b is sufficiently large or when the toner amount of the toner 22 stored in the storage chamber 18b is small.

  Note that the present invention is not limited to the various embodiments described above. The transport sheet 32 only needs to be disposed on the storage chamber 18b side of the partition wall 19 separating the developing chamber 18a and the storage chamber 18b, and the fixing portion 321 of the transport sheet 32 is fixed to the storage chamber surface 19b2 of the bottom wall 19b. Various fixed positions other than the above are applicable.

  The developing device 4 of this embodiment is provided integrally with the process cartridge 7 and is detachable from the main body of the image forming apparatus 100. Alternatively, the developing device 4 may be fixed to the image forming apparatus 100, or the developing device 4 may be formed as a single cartridge and detachable from the main body of the image forming apparatus 100. .

  The image forming apparatus 100 of this embodiment is of an intermediate transfer type having an intermediate transfer belt 5 serving as an intermediate transfer body. In addition, the present invention can be applied to an image forming apparatus having a transport belt formed of an endless belt serving as a recording material carrier for carrying and transporting the recording material 12. In such an image forming apparatus, the toner image formed on the surface of the photosensitive drum 1 is directly transferred onto a recording material 12 carried on a transport belt. In such an image forming apparatus, a transport belt is disposed instead of the intermediate transfer belt 5, and an image forming unit 23 including the process cartridge 7 is disposed below the transport belt. In this case, in the developing device 4, the toner 22 may need to be conveyed against the gravity, and even in such a case, the present invention works effectively.

  According to the present embodiment, when the toner 22 (developer) is conveyed against gravity, the drop of the toner 22 (developer) on the conveyance sheets 32 and 132 can be suppressed. Thus, the toner 22 (developer) can be stably conveyed by the cooperation of the stirring member 31 and the conveying sheets 32 and 132, and the size of the developing device 4 can be reduced.

G: Center of rotation of shaft member 30 (rotation axis)
H: Boundary point between the fixed portion 321 and the displacement portion 322 of the transport sheet 32 L4: Distance between the rotation center G (rotation axis) and the mounting portion 30a L5: Between the mounting portion 30a and the inner wall of the developing frame 18 Q: an imaginary circle passing through the tip (free end 32d) of the displacement portion 322 centered on the boundary point H between the fixed portion 321 and the displacement portion 322 of the conveying sheet 32 18: developing frame (frame)
18a: developing room (first room)
18b ... accommodation room (second room)
19c: Opening 22: Toner (developer)
Reference numeral 30: shaft member 30a: mounting portion 31: stirring member 32: conveying sheet (conveying member)
321: fixed part 322: displacement part

Claims (22)

A developing chamber provided with a developer carrier,
A storage chamber for storing the developer,
A partition partitioning the developing chamber and the storage chamber, the partition provided with an opening that communicates the development chamber and the storage chamber,
A frame body comprising
A stirring member for stirring the developer inside the storage chamber;
A shaft member rotatably supported inside the storage chamber, the shaft member being provided below the opening in the direction of gravity, and having a mounting portion to which the stirring member is mounted;
A transport member that transports the developer inside the storage chamber,
The transport member,
A fixing portion fixed to an inner wall of the frame body forming the storage chamber;
A displacement portion movable with respect to the opening,
With
The fixing portion is fixed to the partition ,
The displacement portion is located between the opening and the shaft member, and moves toward the opening from below the opening in the direction of gravity by being in contact with the stirring member, and moves through the opening to the developing chamber. Ri wherein being configured to convey the developer in contact to,
In a direction orthogonal to the rotation axis of the shaft member, the distance between the rotation axis and the mounting portion is shorter than the shortest distance between the mounting portion and the inner wall, and the rotation axis is connected to the fixed portion. A developing device, wherein the developing device is located inside an imaginary circle passing through a tip of the displacement portion with a boundary point between the displacement portion and the center as a center. A developing chamber provided with a developer carrier ,
A storage chamber for storing the developer ,
A partition partitioning the developing chamber and the storage chamber, the partition provided with an opening that communicates the development chamber and the storage chamber ,
A frame body comprising
A stirring member for stirring the developer inside the storage chamber ;
A shaft member rotatably supported inside the storage chamber, the shaft member being provided below the opening in the direction of gravity, and having a mounting portion to which the stirring member is mounted ;
A transport member that transports the developer inside the storage chamber ,
The transport member ,
A fixing portion fixed to the inner wall of the frame body forming the housing chamber ;
A flexible, movable displacement portion with respect to the opening ,
With
The displacement portion is located between the opening and the shaft member, and is deformed by contacting the stirring member, from below the opening in the direction of gravity, toward the opening, and through the opening. It is configured to transport the developer to the developing chamber ,
In a direction orthogonal to the rotation axis of the shaft member, the distance between the rotation axis and the mounting portion is shorter than the shortest distance between the mounting portion and the inner wall, and the rotation axis is connected to the fixed portion. A developing device, wherein the developing device is located inside an imaginary circle passing through a tip of the displacement portion with a center point at a boundary point with the displacement portion . The stirring member of the developing apparatus according to claim 1 or claim 2, characterized in that it is capable of contacting with the inner wall. In a direction perpendicular to the rotation axis, at least part of the displacement unit, according to any one of claims 1 to 3, characterized in that located between the shaft rotational axis as the opening of the member Developing device. In a direction orthogonal to the rotation axis , at least a part of the displacement portion is located between the attachment portion and the opening while the transport member and the stirring member are in contact with each other. The developing device according to any one of items 1 to 4 . The conveying member, a developing device according to any one of claims 1 to 5, characterized in that at least one of the restoring force or self-weight of the conveying member is contactable to said shaft member or the agitating member . The conveying member, a developing device according to any one of claims 1 6, characterized in that to form a space for storing the developer temporary between the partition wall in which the opening is provided. And the partition wall in which the opening is provided, the angle between the horizontal direction, any one of claims 1, wherein the conveying member is a positive value in the direction to be moved by the stirring member 7 1 Item 6. The developing device according to item 1. The conveying member, the surface opposite the agitating member is the surface contacting the developing device according to any one of claims 1 to 8, characterized in that fixed to the partition wall. The developing device according to claim 1, wherein the stirring member is a member different from the shaft member . The first room,
A second chamber for containing the developer,
A partition partitioning the first chamber and the second chamber, a partition provided with an opening communicating the first chamber and the second chamber,
A frame body comprising
A stirring member for stirring the developer inside the second chamber,
A shaft member rotatably supported inside the second chamber, the shaft member being provided below the opening in the direction of gravity, and having a mounting portion to which the stirring member is mounted;
A transport member that transports the developer inside the second chamber,
The transport member,
A fixing portion fixed to an inner wall of the frame forming the second chamber;
A displacement portion movable with respect to the opening,
With
The fixing portion is fixed to the partition ,
The displacement portion is located between the opening and the shaft member, and moves toward the opening from below the opening in the direction of gravity by contacting the agitating member . Ri is constructed us to convey the developer in the chamber,
In a direction orthogonal to the rotation axis of the shaft member, the distance between the rotation axis and the mounting portion is shorter than the shortest distance between the mounting portion and the inner wall, and the rotation axis is connected to the fixed portion. A developer container, wherein the developer container is located inside an imaginary circle passing through a tip of the displacement part with a boundary point with the displacement part as a center. The first room ,
A second chamber for containing the developer ,
A partition partitioning the first chamber and the second chamber, a partition provided with an opening communicating the first chamber and the second chamber ,
A frame body comprising
A stirring member for stirring the developer inside the second chamber ,
A shaft member rotatably supported inside the second chamber, the shaft member being provided below the opening in the direction of gravity, and having a mounting portion to which the stirring member is mounted ;
A transport member that transports the developer inside the second chamber ,
The transport member ,
A fixing portion fixed to an inner wall of the frame forming the second chamber ;
A flexible, movable displacement portion with respect to the opening ,
With
The displacement portion is located between the opening and the shaft member, and is deformed by contacting the stirring member, from below the opening in the direction of gravity, toward the opening, and through the opening. It is configured to transport the developer to the first chamber ,
In a direction orthogonal to the rotation axis of the shaft member, the distance between the rotation axis and the mounting portion is shorter than the shortest distance between the mounting portion and the inner wall, and the rotation axis is connected to the fixed portion. A developer container, wherein the developer container is located inside an imaginary circle passing through a tip of the displacement part with a boundary point with the displacement part as a center . The developer container according to claim 11, wherein the stirring member is capable of contacting the inner wall. 14. The device according to claim 11 , wherein at least a part of the displacement portion is located between a rotation axis of the shaft member and the opening in a direction orthogonal to the rotation axis. Developer container. In a direction orthogonal to the rotation axis , at least a part of the displacement portion is located between the attachment portion and the opening while the transport member and the stirring member are in contact with each other. developer container according to any one of 11 from 1 4. The conveying member is developed according to any one of claims 11 to 1 5, characterized in that at least one of the restoring force or self-weight of the conveying member is contactable to said shaft member or the agitating member Agent container. The developer container according to any one of claims 11 to 16 , wherein the transport member forms a space for temporarily storing the developer between the partition wall and the partition provided with the opening. And the partition wall in which the opening is provided, the angle between the horizontal direction, claim 11 1-7, wherein the conveying member is a positive value in the direction to be moved by the agitation member 2. The developer container according to claim 1. The developer container according to any one of claims 11 to 18 , wherein a surface of the transport member opposite to a surface with which the stirring member contacts is fixed to the partition. The developer container according to any one of claims 11 to 19, wherein the stirring member is a member different from the shaft member . A developing device according to any one of claims 1 to 10 , or a developer container according to any one of claims 11 to 20 ,
An image carrier on which an electrostatic latent image is formed;
A process cartridge comprising: A developing device comprising the developing device according to any one of claims 1 to 10 , the developer container according to any one of claims 11 to 20 , or the process cartridge according to claim 21 , An image forming apparatus for forming an image on a recording material by using an agent.

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