JP2016161714A - Developing device, process cartridge, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a developing device that can reduce a collision noise between a sheet member conveying developer from a developer storage chamber to a developing chamber and a developer storage chamber-side wall, the noise generated by rotation of the sheet member.SOLUTION: A developing device comprises: a developer storage chamber 18a that is located below a developing chamber 18b including a developer carrier and includes an opening 18c communicated with the developing chamber 18b to store developer; a developer conveying member 30 that includes a first sheet member 32 and a second sheet member 33; a guide part 18a2 that is provided in the developer storage chamber 18a to be in contact with the conveying member 30 and elastically deforms the first sheet member 32 in association with rotation of the conveying member 30; and a release part P that releases the elastic deformation of the first sheet member 32 in order to cause the developer on the conveying member 30 to fly toward the opening 18c.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a developing device, a process cartridge, and an image forming apparatus. In particular, it is suitable for application to a color electrophotographic image forming apparatus.

  Here, the electrophotographic image forming apparatus forms an image on a recording medium using an electrophotographic image forming system. Examples of the electrophotographic image forming apparatus include an electrophotographic copying machine, an electrophotographic printer (for example, a laser beam printer, an LED printer), a facsimile machine, and a word processor.

  The process cartridge refers to a cartridge having at least an image carrier. Many process cartridges have process means that act on the image carrier. Examples of process means include charging means, developing means, and cleaning means. In the process cartridge, the image carrier and the process means are integrally formed as a cartridge, and the cartridge is detachable from the apparatus main body of the image forming apparatus.

  The developing device is a device having at least developing means for developing. In many developing apparatuses, a developing unit, a developing frame that supports the developing unit, and parts related to the developing unit are integrated, and can be attached to and detached from the apparatus main body of the image forming apparatus.

  Further, the developer container is a container for storing the developer, and includes a stirring means for sending out the stored developer.

  In an image forming apparatus such as a printer using an electrophotographic image forming method (electrophotographic process), an electrophotographic photosensitive member (hereinafter referred to as “photosensitive drum”) as an image carrier is uniformly charged. Next, an electrostatic image is formed on the photosensitive drum by selectively exposing the charged photosensitive drum. Next, the electrostatic image formed on the photosensitive drum is visualized as a toner image with toner as a developer. The toner image formed on the photosensitive drum is transferred to a recording material such as recording paper or a plastic sheet, and the toner image is further transferred to the recording material by applying heat or pressure to the recording material. The image is recorded by fixing it to the surface.

  Such an image forming apparatus generally requires maintenance of various process means. In order to facilitate the maintenance of the various process means, it has been put into practical use that the photosensitive drum, the charging means, the developing means, the cleaning means and the like as described above are put together in a frame to form a cartridge. The process cartridge formed into a cartridge is widely used by being detachable from an image forming apparatus (apparatus main body). According to such a process cartridge system, an image forming apparatus having excellent usability can be provided.

  Such a process cartridge is known to have units such as a cleaning unit having a photosensitive drum, a developing unit having a developing unit, and a toner unit for supplying a developer (Patent Documents 1 and 3).

  Further, in the developing unit, a developing carrier for supplying a developer to the photosensitive drum, a developing chamber provided with a developer supplying member for supplying the developer to the developing carrier, and a developing chamber Some have developer storage chambers for storing the developer supplied to the printer. Furthermore, the developer storage chamber may be located below the developing chamber in the direction of gravity, and it may be necessary to supply the developer against gravity.

  As a method of transporting the developer from the developer storage chamber to the development chamber disposed above, there is a method of attaching a flexible sheet member to a stirring member that stirs the developer in the developer storage chamber by a rotating operation. Proposed. Further, there has been proposed a sheet member that abuts against the side wall of the developer accommodating chamber and elastically deforms the sheet member when the developer is transported from the developer accommodating chamber to the developing chamber. There has been proposed a method of conveying developer by a force generated when the sheet member transitions from a deformed state to a natural (restored) state at a release (restoring) position where the elastic deformation of the sheet member is released (patent). Reference 2).

Japanese Patent No. 5067913 JP 2011-253203 A JP 2008-129152 A

  However, in the prior art, when the force generated when the sheet member shifts from the deformed state to the natural (restored) state is large, there is a possibility that the collision noise when the sheet member collides with the side wall becomes large.

Therefore, the present invention provides
A developing chamber having a developer carrying member for carrying the developer;
A storage chamber located below the developing chamber, having an opening connected to the developing chamber, and storing the developer;
A transport member for transporting the developer, the first sheet member and the second sheet member assembled in an overlapping manner;
A deforming portion that is provided in the storage chamber so as to be in contact with the conveying member, and elastically deforms the first sheet member in accordance with the rotation of the conveying member;
A developing device provided in the storage chamber and having a release portion that releases elastic deformation of the first sheet member in order to cause the developer on the transport member to fly toward the opening.

  The present invention also provides a process cartridge and an image forming apparatus.

  According to the present invention, it is possible to reduce the collision noise between the sheet member and the wall of the storage chamber.

Explanatory drawing of the developer conveyance structure of the process cartridge which is an example of embodiment of this invention 1 is a schematic cross-sectional view of an image forming apparatus that is an example of an embodiment of the present invention. 1 is a schematic perspective view of a process cartridge that is an example of an embodiment of the present invention. Schematic sectional view of a process cartridge which is an example of an embodiment of the present invention The schematic perspective view of the conveyance member which is an example of embodiment of this invention The schematic perspective view of the conveyance member which is an example of embodiment of this invention The schematic perspective view of the conveyance member which is an example of embodiment of this invention

[Example 1]
Exemplary embodiments of the present invention will be described below with reference to the drawings. However, the dimensions, materials, shapes, and relative arrangements of the components described in this embodiment should be appropriately selected depending on the configuration of the apparatus to which the invention is applied and various conditions. However, the present invention is not intended to be limited to the following examples.

[Electrophotographic image forming apparatus]
First, an overall configuration as an example of an embodiment of an electrophotographic image forming apparatus (image forming apparatus) according to the present invention will be described with reference to FIG. FIG. 2 is a schematic cross-sectional view of the image forming apparatus 100 of the present embodiment.

  The left and right sides of the drawing are the horizontal direction, and the upper and lower sides are the vertical direction or the gravity direction.

  The image forming apparatus 100 includes, as a plurality of image forming units, first, second, and third images for forming yellow (Y), magenta (M), cyan (C), and black (K) images, respectively. And fourth image forming units SY, SM, SC, and SK.

  In the present embodiment, the configurations and operations of the first to fourth image forming units are substantially the same except that the colors of the images to be formed are different. Therefore, in the following, when there is no particular need for distinction, Y, M, C, and K will be omitted, and a general description will be given. However, the present invention is not limited to this, and a configuration in which the size of the black image forming unit is larger than other image forming units and the toner capacity is increased may be employed. In this case, the image forming conditions are different between the black image forming unit and the other image forming units.

  In this embodiment, the image forming apparatus 100 includes the photosensitive drums 1 (1Y, 1M, 1C, and 1K) as four image carriers in each image forming unit. The photosensitive drum 1 rotates in the direction of the arrow A (see FIG. 1). Around the photosensitive drum 1, a charging roller 2 and a scanner unit (exposure device) 3 are arranged.

  Here, the charging roller 2 is a charging unit that uniformly charges the surface of the photosensitive drum 1. The scanner unit 3 is an exposure unit that irradiates a laser based on image information to form an electrostatic image (electrostatic latent image) on the photosensitive drum 1. Around the photosensitive drum 1, a developing device (hereinafter referred to as a developing unit) 4 (4Y, 4M, 4C, 4K) and a cleaning blade 6 (6Y, 6M, 6C, 6K) as a cleaning unit are arranged. Yes.

  Further, an intermediate transfer belt 5 as an intermediate transfer body for transferring the toner image on the photosensitive drum 1 to the recording material 12 is disposed opposite to the four photosensitive drums 1.

  In this embodiment, the developing unit 4 uses toner T (TY, TM, TC, TK), which is a non-magnetic one-component developer, as a developer. In this embodiment, the developing unit 4 performs contact development by bringing a developing roller 17 as a developer carrying member into contact with the photosensitive drum 1. However, it is not limited to this, and may be magnetic or two-component depending on the configuration. Further, non-contact development may be used.

  In this embodiment, the photosensitive drum 1, the charging roller 2, the cleaning blade 6, and the removed developer storage unit that stores the remaining transfer residual toner (waste toner) (hereinafter referred to as a waste toner storage unit). The photoconductor unit 13 having 14a is formed.

  Further, in this embodiment, the developing unit 4 and the photosensitive unit 13 are integrally formed into a cartridge to form a process cartridge 7. The process cartridge 7 can be attached to and detached from the image forming apparatus 100 via mounting means such as a mounting guide (not shown) and a positioning member provided in the image forming apparatus 100.

  In this embodiment, the process cartridges 7 for the respective colors all have the same shape, and the process cartridges 7 for the respective colors have yellow (TY), magenta (TM), cyan (TC), and black (TK), respectively. ) Of each color is accommodated.

  The intermediate transfer belt 5 is in contact with all the photosensitive drums 1 and rotates in the direction of arrow B in the figure. The intermediate transfer belt 5 is stretched around a plurality of support members (a driving roller 51, a secondary transfer counter roller 52, and a driven roller 53).

  Four primary transfer rollers 8 (8Y, 8M, 8C, 8K) as primary transfer means are arranged in parallel on the inner peripheral surface side of the intermediate transfer belt 5 so as to face the respective photosensitive drums 1. Yes. A secondary transfer roller 9 as a secondary transfer unit is disposed at a position facing the secondary transfer counter roller 52 on the outer peripheral surface side of the intermediate transfer belt 5.

[Image formation process]
At the time of image formation, first, the surface of the photosensitive drum 1 is uniformly charged by the charging roller 2. Next, the surface of the charged photosensitive drum 1 is scanned and exposed by laser light corresponding to the image information emitted from the scanner unit 3, and an electrostatic latent image according to the image information is formed on the photosensitive drum 1. . Next, the electrostatic latent image formed on the photosensitive drum 1 is developed as a toner image by the developing unit 4. The toner image formed on the photosensitive drum 1 is transferred (primary transfer) onto the intermediate transfer belt 5 by the action of the primary transfer roller 8.

  For example, when forming a full-color image, the above-described process is sequentially performed in the first to fourth image forming units SY, SM, SC, and SK, and the toner images of the respective colors are sequentially superimposed on the intermediate transfer belt 5 to be primary. Transcribed. Thereafter, the recording material 12 is conveyed to the secondary transfer portion in synchronization with the movement of the intermediate transfer belt 5. The four-color toner images on the intermediate transfer belt 5 are collectively transferred onto the recording material 12 by the action of the secondary transfer roller 9 that is in contact with the intermediate transfer belt 5 via the recording material 12. The

  The recording material 12 onto which the toner image has been transferred is conveyed to a fixing device 10 as a fixing unit. The toner image is fixed on the recording material 12 by applying heat and pressure to the recording material 12 in the fixing device 10.

  The primary transfer residual toner remaining on the photosensitive drum 1 after the primary transfer process is removed by the cleaning blade 6. Further, the secondary transfer residual toner remaining on the intermediate transfer belt 5 after the secondary transfer step is removed by the intermediate transfer belt cleaning device 11.

  The removed transfer residual toner (waste toner) is discharged to a waste toner box 80 of the image forming apparatus 100.

  The image forming apparatus 100 can also form a single-color or multi-color image using only one or some (not all) image forming units.

[Process cartridge]
Next, the overall configuration of the process cartridge 7 mounted on the image forming apparatus 100 of the present embodiment will be described with reference to FIGS.

  FIG. 3 is a schematic perspective view of the process cartridge 7.

  FIG. 4 is a schematic sectional view of the process cartridge 7.

  The photoconductor unit 13 has a cleaning frame 14 as a frame that supports various elements in the photoconductor unit 13. The photosensitive drum 1 is rotatably attached to the cleaning frame body 14 in the direction of arrow A shown in FIG. 3 via a bearing member.

  A charging roller bearing 15 is attached to the cleaning frame 14 along a line passing through the rotation center of the charging roller 2 and the rotation center of the photosensitive drum 1. Here, the charging roller bearing 15 is attached so as to be movable in the direction of arrow C shown in FIG. The charging roller 2 is rotatably attached to the charging roller bearing 15. The charging roller bearing 15 is urged toward the photosensitive drum 1 by a charging roller pressing spring 16 as urging means.

  The cleaning blade 6 includes an elastic member 6a for removing transfer residual toner (waste toner) remaining on the surface of the photosensitive drum 1 after the primary transfer, and a support member 6b for supporting the elastic member. Is formed.

  The waste toner removed from the surface of the photosensitive drum 1 by the cleaning blade 6 falls in the direction of gravity in the space formed by the cleaning blade 6 and the cleaning frame 14, and is stored in the waste toner storage portion 14a.

  The developing unit 4 has a developing frame 18 that supports various elements in the developing unit 4. The developing unit 4 is provided with a developing roller 17 as a developer carrying member that contacts the photosensitive drum 1 and rotates in the direction indicated by an arrow D (counterclockwise). The developing roller 17 is supported by the developing frame 18 via bearings at both ends in the longitudinal direction (rotation axis direction).

  Further, the developing unit 4 includes a developer storage chamber (hereinafter, toner storage chamber) 18a and a development chamber 18b in which a developing roller 17 that is a developer carrying member is disposed.

  In the developing chamber 18b, a toner supply roller 20 as a developer supply member that contacts the developing roller 17 and rotates in the direction of arrow E, and a developing blade 21 as a developer regulating member for regulating the toner layer of the developing roller 17 are provided. Is arranged.

  The toner storage chamber 18a of the developing frame 18 is provided with a transport member 30 for stirring the stored toner T and transporting the toner to the toner supply roller 20, and transports the toner on the transport member. .

  The developing unit 4 is coupled to the photosensitive unit 13 so as to be rotatable about a fitting shaft 22 fixedly supported by the cleaning frame 14. The developing unit 4 is urged by a pressure spring (a tension spring) 23. Therefore, when the image is formed on the process cartridge 7, the developing unit 4 rotates around the fitting shaft 22, and the photosensitive drum 1 and the developing roller 17 come into contact with each other.

[Toner transport configuration]
Next, the toner conveying configuration of the developing unit 4 of the process cartridge 7 in the embodiment according to the present invention will be described in detail with reference to FIGS. 1, 5, 6, and 7. FIG.

  The developing unit 4 includes a developing chamber 18b and a toner storage chamber 18a. In the developing chamber 18b, a developing roller 17, a supply roller 20, a developing blade 21, and the like are arranged. The toner storage chamber 18a is provided with a toner conveying member 30 that stores toner supplied to the developing chamber 18b and supplies toner to the developing chamber 18b. The toner storage chamber 18a is disposed vertically below the developing chamber 18b. Therefore, it is necessary to convey the toner against the gravity from the toner storage chamber 18a to the development chamber 18b.

  A side wall 18d having an opening 18c through which the toner passes is provided between the developing chamber 18b and the toner storage chamber 18a. Hereinafter, for convenience, the toner storage chamber 18a will be described as having an opening. Here, the opening 18c is provided above the toner storage chamber 18a. In addition, in the toner storage chamber 18a, the toner conveying member 30 has an elastic first sheet member 32 that can rotate on the conveying shaft (stirring shaft) 31 in the direction of arrow K in order to supply toner to the developing chamber 18b. Supported. The toner conveying member 30 is rotatably supported by the developing device frame 18 forming the toner storage chamber 18a at both ends in the longitudinal direction (rotation axis direction). The toner conveying member 30 is rotationally driven in the direction of arrow K by a driving means (not shown).

  In the toner storage chamber 18a, a guide portion 18a2 serving as a deforming portion that comes into contact with the first sheet member 32 is provided below the opening 18c. The first sheet member 32 comes into contact with the guide portion 18a2 along with the rotation thereof. Thereby, the first sheet member 32 receives a force from the guide portion 18a2. As a result, the first sheet member 32 is deformed against the elastic force of the first sheet member 32. Further, the first sheet member 32 rotates while being in contact with the guide portion 18a2, thereby conveying the toner on the surface on the downstream side in the rotation direction. In the present embodiment, the guide portion 18a2 refers to the inner wall of the toner storage chamber 18a as shown in FIG. 1 up to the point p where the first sheet member 32 is separated. The toner storage chamber 18a is provided with a restoring portion 18a4 including a release portion on the downstream side of the guide portion 18a2 and the upstream side of the opening 18c in the rotation direction of the first sheet member 32. Here, the release portion is a portion for releasing contact between the first sheet member 32 and the inner wall of the toner storage chamber 18a, and is a point P in this embodiment.

  With the rotation of the first sheet member 32, the free end side of the first sheet member 32 (the inner wall side of the toner storage chamber 18a) passes through the guide portion 18a2, and then the toner storage chamber 18a of the first sheet member 32 is moved. The contact with the inner wall is released. Then, the first sheet member 32 is released from the state of being elastically deformed by the guide portion 18a2, and is restored to the natural state (original shape) by its own elastic restoring force. Due to the shape change in the restoring direction of the first sheet member 32, the toner carried and conveyed on the first sheet member 32 flies against the gravity toward the opening 18 c.

  In this embodiment, as shown in FIG. 5, the second sheet member 33 is overlapped and fixed on the same surface as the surface (31 a) of the stirring shaft 31 that fixes the first sheet member 32 to the toner conveying member 30. However, the present invention is not limited to this, and a thin sheet member may be sandwiched between the first sheet member 32 and the second sheet member, and may be attached to the same surface. However, it is preferable that the first sheet member 32 and the second sheet member 33 are overlapped with each other and attached to the stirring shaft that is a part of the conveying member. In this embodiment, as can be seen from FIG. 5, the length of the stirring shaft 31 in the rotation axis direction is the same for the first sheet member and the second sheet member. As a result, the handling is facilitated and the manufacturing process is not complicated.

  For attachment, the protrusion 31c is provided on one surface 31a of the plurality of surfaces (31a, b) of the agitation shaft 31, the hole of the sheet member having the hole is engaged with the protrusion, and the tip of the protrusion is melted and fixed. The method is preferred. However, the present invention is not limited to this, and a structure having a hooking structure on the stirring shaft and hooking and attaching the hole of the sheet member may be used. The second sheet member 33 is disposed on the upstream side of the first sheet member 32 with respect to the rotation direction K, and the sheet leading end is formed short. That is, the stirring shaft 31, the second sheet member 33, and the first sheet member 32 are attached in this order.

  In the present embodiment, the second sheet member 33 and the first sheet member 32 have the sheet surface of the second sheet member in contact with the surface of the first sheet member 32. Assuming that the portion of the first sheet member 32 that is in contact with the second sheet member 33 is a contact portion, the contact portion is reinforced by the second sheet member 33 and is less bent than the first sheet member portion that is not in contact. Become. This is that when the developer on the first sheet member is conveyed while rotating, the free end of the second sheet member rotates with the first sheet member in contact therewith.

  As a result, as shown in FIG. 6, the second sheet member 33 can impart stiffness to the first sheet member 32, and when the amount of toner T is large, even if the first sheet member 32 is thin, it is difficult to bend greatly. Become. Therefore, the first sheet member 32 can be brought into contact with the guide portion 18a and can be elastically restored after passing through the point P, so that the toner transportability is improved.

  As shown in FIG. 1, when the amount of toner in the toner storage chamber 18a is small, the first sheet member 32 is a first sheet member that is in contact with the leading end 33a of the second sheet member 33 or the leading end of the second sheet member. Bend around the part. Thereby, the bending amount of the 1st sheet member 32 whole can be controlled, and the collision sound generated when it collides with side wall 18d which forms opening 18c can be reduced.

  In order to prevent the second sheet member 33 from colliding with the side wall 18d, the following relationship is preferable when viewed from the rotation center of the toner conveying member as shown in FIG. First, the distance to the side wall 18d that forms the opening 18c is L1, and the distance L2 to the deformed portion 18a2. In this case, the length r1 from the assembly position of the second sheet member 33 to the free end is desirably shorter than the distance L1 to the side wall 18d forming the opening 18c and the distance L2 to the deformed portion 18a2.

  In this embodiment, as can be seen from FIG. 7, when the conveying member is rotated, the first sheet member is bent so that the free end of the first sheet is upstream in the rotational direction with respect to the free end of the second sheet. Will be located. That is, the free end of the second sheet is located on the downstream side. If not bent, the position of the first sheet is reversed because the first sheet is downstream in the rotation direction and the second sheet is upstream in the rotation direction.

  The 1st sheet member 32 and the 2nd sheet member 33 can be suitably produced using flexible resin-made sheets, such as a polyester film, a polyphenylene sulfide film, and a polycarbonate film, for example. The thickness of the first sheet member 32 and the second sheet member 33 is preferably 50 μm to 250 μm. Further, it is preferable that the same material is used.

4 Developing Unit 7 Process Cartridge 17 Developing Roller (Developer Carrier)
18 Development frame 18a Storage chamber 18a2 Guide part (deformation part)
18a4 Restoration part including release part 18b Developing chamber 18c Opening 18d Side wall 30 Conveying member 31 Stirring shaft 32 First sheet member 33 Second sheet member 100 Image forming apparatus

Claims (10)

A developing chamber having a developer carrying member for carrying the developer;
A storage chamber located below the developing chamber, having an opening connected to the developing chamber, and storing the developer;
A transport member for transporting the developer, the first sheet member and the second sheet member assembled in an overlapping manner;
A deforming portion that is provided in the storage chamber so as to be in contact with the conveying member, and elastically deforms the first sheet member in accordance with the rotation of the conveying member;
A developing device, comprising: a release portion that is provided in the storage chamber and releases elastic deformation of the first sheet member in order to cause the developer on the conveying member to fly toward the opening.   The developing device according to claim 1, wherein the first sheet member is located downstream of the second sheet member in the rotation direction of the transport member.   The developing device according to claim 1, wherein the first sheet member has a longer length from an assembly position to a free end than the second sheet member.   4. The developing device according to claim 1, wherein the free end of the second sheet member rotates in a state of being in contact with the first sheet member. 5. When the transport member rotates and transports the developer,
5. The free end of the second sheet member is located downstream of the free end of the first sheet member in the rotation direction of the transport member. 6. Development device.   The length from the assembly position of the second sheet member to the free end is shorter than the distance from the rotation center of the transport member to the deformed portion and the distance from the rotation center to the wall having the opening. The developing device according to any one of claims 1 to 5.   The developing device according to claim 1, wherein a length of the first sheet member in a rotation axis direction of the transport member is the same as a length of the second sheet member.   The developing device according to claim 1, wherein the first sheet member and the second sheet member are formed of the same material. An image carrier;
A process cartridge comprising: the developing device according to claim 1.   An image forming apparatus comprising at least one of the developing device according to claim 1 and the process cartridge according to claim 9, and forming an image on a recording material.

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