JP2012032662A - Developing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a developing device capable of decreasing collision noise caused by collision of a developer agitating and conveying member on an edge of an opening of a partition wall provided between a developing chamber and a developer container of the developing device, without increasing the distance between edges of the opening.SOLUTION: A sheet member 148 of a toner agitating and conveying member 149 is distorted just before passing over an inner end (upstream end) 146c of a toner container 144 at an edge 146a in an upstream side of a toner supply opening 146, and then is brought into contact with an inner end (downstream end) 146b of the toner container 144 at an edge 146b in a downstream side of the toner supply opening 146 immediately after the free end 148a passes the upstream end 146c and the sheet member restores a shape in a natural state. In a rotation radial direction of the toner agitating and conveying member 149, the distance between the downstream end 146b and the rotation axial line 149a of the toner agitating and conveying member 149 is smaller than the distance between the upstream end 146c and the rotation axial line 149a.

Description

  The present invention relates to a developing device used in an image forming apparatus such as a copying machine or a laser beam printer using an electrophotographic system.

  An image forming apparatus using an electrophotographic system is provided with a developing device that develops an electrostatic latent image formed on an electrophotographic photosensitive member (photosensitive member) using a powder developer called toner. . A process cartridge is also widely known in which a photoconductor and process means such as a developing device acting on the photoconductor are integrated so as to be detachable from the image forming apparatus main body.

  FIG. 11 shows a cross section of an example of a conventional process cartridge. In the illustrated process cartridge 207, a cleaning device 206 and a developing device 204 are disposed with a photosensitive drum 201, which is a drum-type photosensitive member, interposed therebetween. A charging device 202 is disposed between the cleaning device 206 and the developing device 204.

  The developing device 204 includes a developing chamber 243 provided with a developing roller 241 as a developer carrying member and a developing blade 242 as a developer regulating member, and a developer container in which toner to be supplied to the developing chamber 243 is stored. And a toner container 244. The developing chamber 243 and the toner container 244 are partitioned by a partition wall 245, and a toner supply opening (opening) 246 is formed in the partition 245. In the toner container 244, a toner stirring and conveying member 249 is provided as a developer stirring and conveying member that stirs the toner T in the toner container 244 and conveys the toner T to the developing chamber 243. The toner stirring and conveying member 249 includes a support member 247 and a flexible sheet member 248 as a stirring blade fixed to the support member 247. The opening 246 is covered with a toner seal member (not shown) after the toner T is filled in the toner container 244. As a result, the toner T is sealed in the toner container 244, and toner leakage during transport of the process cartridge 207 is prevented.

  The toner agitating / conveying member 249 rotates clockwise in the figure as the support member 247 rotates around the rotation center (rotation axis) 249a of the toner agitating / conveying member 249. The free end 248a of the sheet member 248 is once released from bending stress when passing through the upstream edge portion (hereinafter referred to as “upstream edge portion”) 246a of the opening 246 in the rotation direction of the toner stirring and conveying member 249. Is done. Further, the free end 248a of the sheet member 248 is released from the bending stress, so that the downstream edge of the opening 246 in the rotation direction of the toner agitating / conveying member 249 (hereinafter referred to as “downstream edge”) 246b. Clash with. The sheet member 248 conveys the toner T into the developing chamber 243 by the impact force due to the release of the bending stress and the collision with the downstream edge 246b as described above. A toner conveying method using a sheet member is described in Patent Document 1, for example.

JP-A-3-131881

  However, the toner transport method as described above has the following problems.

  That is, when the free end 248a of the sheet member 248 passes through the upstream edge 246a of the opening 246, the bending stress applied to the free end 248a is released. As a result, the free end 248a of the sheet member 248 collides with the downstream edge 246b of the opening 246 to generate a collision sound.

  Since this collision sound is generated every rotation period of the toner agitating / conveying member 249, it can be easily heard. In addition, when the remaining amount of toner in the toner container 244 decreases, there is nothing that hinders the movement of the free end 248a of the sheet member 248, so this collision noise tends to increase.

  If the distance between the upstream edge 246a and the downstream edge 246b of the opening 246 is increased, it is considered that the above-described collision can be avoided. However, this method is not preferable because the following situation may occur. That is, there is a concern about an increase in cost due to an increase in the area of the toner seal member used to close the opening 246. Further, there is a concern that the strength of the frame (housing) of the developing device 204 may be reduced. Furthermore, there is a concern that the rate at which the toner T once transported to the developing chamber 243 flows back into the toner container 244 increases.

  Accordingly, an object of the present invention is to convey the developer agitated to the edge of the opening without increasing the distance between the edges of the opening provided in the partition wall between the developing chamber of the developing device and the developer container. It is an object of the present invention to provide a developing device capable of reducing a collision sound caused by a collision of members.

  The above object is achieved by the developing device according to the present invention. In summary, the present invention provides a developing chamber in which a developer carrying member for carrying a developer is disposed, a developer container in which a developer to be supplied to the developing chamber is stored, the developing chamber, and the developer container. And a partition wall formed with an opening for communicating the developing chamber and the developer container, and disposed inside the developer container for stirring the developer in the developer container A developer agitating / conveying member rotatable to convey the developer from the developer container into the developing chamber through the opening; and the developer agitating / conveying member rotates about a rotation axis. A support member that is possible, and a flexible sheet member that is fixed to the support member and is rotatable about the rotation axis on the outer side in the rotational radial direction of the developer agitating and conveying member than the support member, The rotation axis Each of the first direction and the second direction orthogonal to the first direction has a predetermined width, and one end of the second direction is fixed to the support member and the other end A sheet member having a free end, and the sheet member is an inner edge of the developer container at an upstream edge of the opening in the rotation direction of the developer agitating and conveying member. The free end is bent by coming into contact with the inner wall surface of the developer container until just before passing through an upstream end, and the free end passes through the upstream end to have a natural shape. Immediately after the restoration, the downstream edge of the opening in the rotational direction is in contact with the downstream end which is the inner end of the developer container, and in the rotational radius direction of the developer agitating and conveying member More than the distance between the upstream end and the rotation axis, A developing apparatus is characterized in that the smaller of the distance between the flow-side end portion and the axis of rotation.

  According to the present invention, the developer agitating and conveying member is provided at the edge of the opening without increasing the distance between the edges of the opening provided in the partition wall between the developing chamber of the developing device and the developer container. It is possible to reduce the collision sound caused by the collision.

1 is a schematic cross-sectional view of an image forming apparatus according to an embodiment of the present invention. It is a schematic sectional drawing of the process cartridge which concerns on one Example of this invention. 1 is a schematic sectional view of a developing device according to an embodiment of the present invention. FIG. 3 is a schematic perspective view of the vicinity of an opening in a developing device according to an embodiment of the present invention. FIG. 6 is a schematic cross-sectional view of a developing device according to an embodiment of the present embodiment for explaining a toner conveyance state in a rotation process of a toner stirring and conveying member. FIG. 10 is a schematic diagram illustrating how the sheet member of the toner agitating / conveying member of the developing device according to an embodiment of the present invention bends. It is a schematic diagram which shows the other example of the form of the opening part with which the developing device which concerns on one Example of this invention is provided. It is a schematic perspective view of the vicinity of the opening part in the developing device concerning other examples of the present invention. It is a schematic sectional drawing of the vicinity of the opening part in the image development apparatus concerning the other Example of this invention. FIG. 6 is a schematic cross-sectional view showing another form of the support member of the toner stirring and conveying member. It is a schematic sectional drawing of an example of the conventional process cartridge.

  Hereinafter, the developing device according to the present invention will be described in more detail with reference to the drawings.

Example 1
In the present embodiment, the present invention is applied to a developing device of a process cartridge type laser beam printer using an electrophotographic system.

1. Image Forming Apparatus First, the overall configuration and operation of the image forming apparatus according to the present embodiment will be described. FIG. 1 shows a schematic cross section of an image forming apparatus 100 of the present embodiment.

  The image forming apparatus 100 includes a photosensitive drum 101 that is a drum-type photosensitive member as an image carrier. The following means are arranged around the photosensitive drum 101. First, a charging roller 102 as a charging unit. Next, a laser scanner (exposure device) 103 as an exposure unit. Next, there is a developing device 104 as a developing unit. Next, a transfer roller 105 as a transfer unit. Next, a cleaning device 106 as a cleaning unit. The image forming apparatus 100 also includes a transfer material conveyance mechanism 108 as a transfer material conveyance unit, a heating and pressure fixing unit (fixing unit) 109 as a fixing unit, and the like.

  At the time of image formation, the photosensitive drum 101 is rotationally driven clockwise in the drawing, and the surface thereof is uniformly charged by the charging roller 102. The surface of the charged photosensitive drum 101 is exposed by a laser beam corresponding to image information by the exposure device 103. As a result, an electrostatic latent image (electrostatic image) is formed on the photosensitive drum 101. The electrostatic latent image formed on the photosensitive drum 101 is developed as a toner image with toner as a developer attached by the developing device 104. The toner image formed on the photosensitive drum 101 is electrostatically transferred to the transfer material P in a contact area (transfer nip) N where the photosensitive drum 101 and the transfer roller 105 are in contact with each other. The transfer material P is transferred one by one from the transfer material storage cassette 181 by the transfer material supply roller 182 in the transfer material transport mechanism 108, and then transferred in synchronization with the toner image on the photosensitive drum 101 by the registration roller 183. It is conveyed to the nip N. The transfer material P onto which the toner image has been transferred in the transfer nip N is separated from the surface of the photosensitive drum 101 and conveyed to the fixing device 109. The fixing device 109 fixes the unfixed toner image on the transfer material P by heating and pressurizing the transfer material P carrying the unfixed toner image. The transfer material P on which the toner image is fixed is discharged to the outside of the image forming apparatus 100. Further, toner (transfer residual toner) remaining on the surface of the photosensitive drum 101 after the toner image is transferred to the transfer material P is removed from the photosensitive drum 101 and collected by the cleaning device 106.

  In this embodiment, the charging roller 102 and the exposure device 103 constitute an electrostatic image forming unit that forms an electrostatic image on the photosensitive drum 101.

2. Process Cartridge In this embodiment, the photosensitive drum 101 and the charging roller 102, the developing device 104, and the cleaning device 106 as process means acting on the photosensitive drum 101 are a process cartridge 107 that can be attached to and detached from the main body of the image forming apparatus 100. It is constructed integrally. FIG. 2 shows a schematic cross section of the process cartridge 107 according to the present embodiment.

  The process cartridge 107 is configured by connecting a developing unit 104 with a photosensitive unit 107a in which a photosensitive drum 101, a charging roller 102, and a cleaning device 106 are integrally formed by a frame.

  The cleaning device 106 includes a cleaning blade 161 as a cleaning member disposed in contact with the surface of the photosensitive drum 101, and a waste toner container 162 that stores toner removed from the photosensitive drum 101. The cleaning device 106 scrapes off the transfer residual toner from the surface of the rotating photosensitive drum 101 by the cleaning blade 161 and collects it in the waste toner container 162.

  The developing device 104 includes a developing chamber 143 provided with a developing roller 141 as a developer carrying member and a developing blade 142 as a developer regulating member, and a developer container in which toner to be supplied to the developing chamber 143 is stored. And a toner container 144. The developing chamber 143 and the toner container 144 are partitioned by a partition wall 145, and a toner supply opening (opening) 146 that connects the developing chamber 143 and the toner container 144 is formed in the partition 145. Yes. In this embodiment, the opening 146 is a rectangular through-hole having a long side parallel to the longitudinal direction of the developing device 104 and a short side orthogonal to the long side when viewed from the developing chamber 143 side. Further, in the toner container 144, a rotatable toner stirring and conveying member 149 is provided as a developer stirring and conveying member that stirs the toner T in the toner container 144 and conveys the toner T to the developing chamber 143. The toner stirring / conveying member 149 includes a support member 147 and a flexible sheet member 148 serving as a stirring blade fixed to the support member 147. The opening 146 is covered with a toner seal member (not shown) after the toner T is filled in the toner container 144. As a result, the toner T is sealed in the toner container 144, and toner leakage is prevented from occurring when the process cartridge 107 is transported.

  The developing roller 141 carries the toner in the developing chamber 143 and conveys the toner to a developing unit facing the photosensitive drum 101. The developing blade 142 regulates the amount (layer thickness) of toner carried on the developing roller 141.

3. FIG. 3 shows a schematic cross section of the developing device 104 according to this embodiment. The toner agitating / conveying member 149 rotates clockwise in the figure as the support member 147 rotates about the rotation center (rotation axis) 149a of the toner agitating / conveying member 149. As shown in FIGS. 5A to 5D, the toner stirring and conveying member 149 plays a role of conveying the toner T necessary for the developing operation from the toner container 144 to the developing chamber 143 in the rotation process.

  The support member 147 has a shaft portion 147a extending in the longitudinal direction of the developing device 104 (parallel to the rotation axis of the developing roller 141) with substantially the same cross-sectional shape that is square in this embodiment. The rotation axis 149a is located at the approximate center of the cross section of the shaft portion 147a. Further, the support member 147 has a support portion 147b in which one side surface extending in the longitudinal direction of the shaft portion 147a extends outward in the rotational radial direction of the toner agitating / conveying member 149 along a surface orthogonal to the rotation axis 149a. In this embodiment, the shaft portion 147a and the support portion 147b of the support member 147 are integrally formed.

  In this embodiment, the support member 147 has a configuration in which the shaft portion 147a closer to the rotation axis 149a and the support portion 147b for attaching the sheet member 148 are integrated, but the present invention has such a configuration. It is not limited. For example, as shown in FIG. 10, the support member 147 is not provided with the support portion 147b in this embodiment, and the sheet member 148 is attached to the support member 147 corresponding to the shaft portion 147a in this embodiment. It may be. Further, the cross-sectional shape of the shaft portion 147a is not limited to a quadrangle, and the sheet member 148 may be appropriately attached.

  The sheet member 148 is in a first state parallel to the rotation axis 149a of the toner agitating / conveying member 149 and a second direction orthogonal to the first direction in a natural state (a state where no bending force is applied). It is a flat thin plate member having a predetermined width. In particular, in this embodiment, the sheet member 148 includes the first direction (longitudinal direction) over substantially the entire longitudinal direction of the developing device 104, and the second direction (short direction) perpendicular to the first direction. Are flat rectangular thin plate members each having a predetermined length. That is, the second direction (short direction) of the sheet member 148 is parallel to a plane orthogonal to the rotation axis 149a of the toner stirring and conveying member 149. One end of the sheet member 148 in the short direction is fixed to the support portion 147 b of the support member 147. The other end of the sheet member 148 in the short direction (hereinafter, also simply referred to as “free end”) is parallel to the rotation axis 149 a of the toner stirring and conveying member 149. In the present embodiment, the sheet member 148 has a free end from an end portion (hereinafter also referred to as “fixed end”) 148b (see FIG. 6) of the fixed portion to the support member 147 in the short direction. The portions up to 148a are flexible and elastically deformable. In this embodiment, the fixed end 148b is located at a position corresponding to the end 147c of the support portion 147b of the support member 147. The sheet member 148 rotates (circulates) around the rotation axis 149a of the toner agitating / conveying member 149 outside the support member 147 in the rotational radius direction of the toner agitating / conveying member 149, and agitates and rotates the toner at the corresponding position. Transport.

  More specifically, the toner T, which is a powder, is deposited on the lower side of the toner container 144 by gravity. Therefore, in order to convey the toner T in the toner container 144 to the developing chamber 143 through the opening 146, the toner stirring and conveying member 149 needs to be configured as follows. That is, after at least the free end 148a passes the lowest point of the toner container 144 and reaches the upstream edge 146a of the opening 146, the free end 148a is the inner wall surface (conveying surface) of the toner container 144 in the range. It is necessary to keep in contact with 144a with an intrusion amount. Accordingly, the sheet member 148 can scoop up toner accumulated on the bottom of the toner container 144 in cooperation with the inner wall surface (conveying surface) 144a.

  Further, in order to efficiently convey the toner T deposited on the lower side of the toner container 110, the toner stirring and conveying member 149 needs to be configured as follows. That is, at least the free end 148a is elastic from the shape bent by the inner wall surface (conveying surface) 144a after passing through the upstream edge 146a of the opening 146 to the shape in the natural state (flat thin plate shape). It is necessary to have flexibility that can be restored. When the sheet member 148 is bent by the inner wall surface (conveying surface) 144a, the sheet member 148 has a curved shape so as to protrude toward the downstream side in the rotation direction.

  On the other hand, in order to rotate the toner stirring and conveying member 149 in the toner T, the toner stirring and conveying member 149 needs to be configured as follows. That is, at least the support member 147 in the vicinity of the rotation axis 149 a needs to have a strength sufficient to resist the resistance force of the toner T.

  In the present embodiment, the toner agitating / conveying member 149 includes a support member 147 and a sheet member 148 so as to satisfy such a condition. More specifically, in this embodiment, the support member 147 of the toner stirring and conveying member 149 is made of PS (polystyrene) resin for both the shaft portion 147a and the support portion 147b. In this embodiment, the shaft portion 147a and the support portion 147b of the support member 147 are integrally formed. In this example, the entire sheet member 148 including the free end 148a was made of a sheet of PC (polycarbonate) resin having a thickness of 75 μm. However, the materials of the support member 147 and the sheet member 148 are not limited to those of the present embodiment. For example, the materials used in the present embodiment may be appropriately selected and used from materials similar in strength to those of the present embodiment. Can do. In this embodiment, the toner agitating / conveying member 149 rotates at a rotation speed of 1 rotation / second.

  Here, when the process cartridge 107 is not used, a toner seal member is affixed to the end surface of the opening 146 on the developing chamber 143 side. The toner seal member seals the toner T in the toner container 144, thereby preventing toner leakage when the process cartridge 107 is transported. However, if the width of the opening 146 in the short side direction (that is, the distance between the upstream edge 146a and the downstream edge 146b of the opening 146) is too wide, the area of the toner seal member becomes too large. , Become a factor of cost increase. If the width of the opening 146 in the short side direction is too wide, the strength of the frame (housing) of the developing device 104 is reduced. Furthermore, if the width of the opening 146 in the short side direction is too wide, the ratio of the backflow of the toner T from the developing chamber 143 to the toner container 144 may increase.

  However, when the width of the opening 146 in the short side direction is narrow, the free end 148a of the sheet member 148 collides with the downstream edge 146b of the opening 146, and a collision sound is generated. More specifically, when the free end 148a of the sheet member 148 passes through the upstream edge 146a of the opening 146, the bending stress applied to the free end 148a is released. As a result, the free end 148a that has been bent up to that point is elastically restored to its natural state. At this time, when the width of the opening 146 in the short side direction is narrow, the free end 148a is the downstream edge of the opening 146 only by the movement of the sheet member 148 elastically restored to the shape in the natural state. Collide with 146b. A collision sound is generated by this collision.

  When the free end 148a of the sheet member 148 collides with the downstream edge 146b of the opening 146, the following effects are obtained. In other words, the toner T adhering to the sheet member 148 including the free end 148a has an effect of being peeled off by an impact at the time of collision between the free end 148a and the downstream edge 146b of the opening 146. Therefore, the above-described collision is necessary for the toner agitating / conveying member 149 to perform the toner conveying function.

4). Suppression of collision sound One of the objects of the present embodiment is to reduce the collision sound caused by the collision of the toner agitating / conveying member 149 with the edge of the opening 146. More specifically, when the free end 148a passes through the upstream edge 146a of the opening 146, the bending stress applied to the free end 148a is released, so that the free end 148a and the opening 146 are released. The collision noise caused by the collision with the downstream edge portion 146b is reduced.

  Therefore, in the present embodiment, the developing device 104 is roughly configured as follows. That is, the position where the downstream edge 146b of the opening 146 collides with the sheet member 148 of the toner stirring and conveying member 149 is set as close to the rotation axis 149a side of the toner stirring and conveying member 149 as possible. Accordingly, it is possible to reduce a collision sound when the sheet member 148 of the toner agitating / conveying member 149 collides with the downstream edge 146b of the opening 146. This is because the sheet member 148 can collide with the downstream edge 146b of the opening 146 at a position where the moving speed is slower. However, since the sheet member 148 is more greatly bent when passing through the downstream edge 146b of the opening 146, the toner agitating / conveying member 149 is as much as possible within a range where the sheet member 148 is not permanently deformed. The rotation axis 149a side is preferable.

  In other words, in this embodiment, the toner agitating and conveying member 149 includes a support member 147 and a flexible sheet member 148 having one end fixed to the support member 147 and the other end being a free end. The free end 148a of the sheet member 148 comes into contact with the inner wall of the toner container 144 (the partition 145 between the developing chamber 143 and the toner container 144) before and after passing through the opening 146. More specifically, the inner edge (upstream edge) 146c of the upstream edge 146a of the opening 146 and the inner edge (downstream) of the toner container 144 at the downstream edge 146b. (End part) 146d is contacted respectively. The sheet member 148 is curved by the end portion 146c of the upstream edge portion 146a so as to protrude toward the downstream side in the rotation direction of the toner stirring and conveying member 149 until just before the free end 148a passes therethrough ( FIG. 5B and FIG. 6). Further, the sheet member 148 is also curved by the end portion 146d of the downstream edge portion 146b so as to protrude toward the downstream side in the rotation direction of the toner agitating / conveying member 149 when the free end 148a passes therethrough. (See FIG. 5D). On the other hand, the free end 148a of the sheet member 148 does not contact the inner wall of the toner container 144 (the partition 145 between the developing chamber 143 and the toner container 144) when passing through the opening 146 (FIGS. 4 and 4). 5 (c)). Further, the sheet member 148 contacts the end 146d of the downstream edge 146b immediately after its free end 148a passes through the end 146c of the upstream edge 146a and is almost in its natural state ( Clash). Then, the downstream end 146d and the rotation axis of the toner agitating / conveying member 149 are larger than the distance d1 between the upstream end 146c and the rotation axis 149a of the toner agitating / conveying member 149 in the rotational radius direction of the toner agitating / conveying member 149. The distance d2 between 149a is made smaller.

  FIG. 4 is a perspective view showing the vicinity of the opening 146 of the developing device 104. In FIG. 4, the sheet member 148 of the toner stirring and conveying member 149 is in the opening 146. In the present embodiment, the substantially flat partition wall 145 on the downstream edge 146b side of the opening 146 has a substantially L-shaped cross section that extends to the inside of the toner container 144 so as to extend the downstream edge 146b. An overhang portion 145a is formed. As a result, the end 146d of the downstream edge 146b protrudes toward the rotation axis 149a of the toner agitating / conveying member 149 from the inner wall surface (conveying surface) 144a of the toner container 144. In this embodiment, the shape of the downstream edge 146 b of the opening 146 is the same over substantially the entire area of the developing device 104 in the longitudinal direction.

  Next, the setting for obtaining the maximum effect of the present embodiment will be described in more detail.

  As described above, the free end 148 a of the sheet member 148 needs to have an intrusion amount with respect to the inner wall surface (conveying surface) 144 a of the toner container 144. As the amount of penetration increases, the toner conveying force increases, but the amount of deflection of the free end side of the sheet member 148 also increases. As a result, the collision noise caused by the collision between the sheet member 148 and the downstream edge 146b of the opening 146 also increases.

  FIG. 6 shows how the sheet member 148 of the toner stirring and conveying member 149 is bent. A state of the sheet member 148 immediately before the free end 148a of the sheet member 148 is separated from the end 146c of the upstream edge 146a is represented by a solid line X. The state of the sheet member 148 immediately after the free end 148a of the sheet member 148 is separated from the end 146c of the upstream edge 146a is represented by a broken line Y.

  Here, when it is assumed that the toner stirring and conveying member 149 rotates while the sheet member 148 is in a natural state, the length of each part in the rotation process of the toner stirring and conveying member 149 is defined as follows. The length from the fixed end 148b to the free end 148a (hereinafter also referred to as “free length”) in the short direction of the sheet member 148 is B. The length from the fixed end 148b to the end 146c of the upstream edge 146a along the short direction of the sheet member 148 is C. A length (hereinafter also referred to as a “collision position distance”) from the fixed end 148b to the end 146d of the downstream edge 146b along the short direction of the sheet member 148 is defined as D. The length from the upstream edge 146a to the downstream edge 146b of the opening 146 is h. At this time, as described above, in order for the free end 148a of the sheet member 148 to contact the inner wall surface (conveying surface) 144a of the toner container 144 with an intrusion amount, the relationship of C <B is satisfied. When the value of h satisfies the following expression (1), the sheet member 148 has its free end 148a passing through the end 146c of the upstream edge 146a, and substantially in its natural state (the broken line Y Immediately after becoming (state), it contacts (collises) the end 146d of the downstream edge 146b.

  The above equation (1) is derived from geometric conditions. In order to satisfactorily convey the toner T from the toner container 144 to the developing chamber 143, the value of h is 1.5 mm or more, more preferably 2.0 mm or more.

  Under conditions satisfying the above formula (1), the occurrence of impact noise and permanent deformation (sagging) of the sheet member 148 was examined. The value of B−C, that is, the amount of penetration of the free end 148a of the sheet member 148 into the inner wall surface (conveying surface) 144a of the toner container 144 was fixed to 2 mm. Then, the value of B, that is, the free length of the sheet member 148 is changed to 20 mm, 30 mm, and 40 mm, and for each case, the value of D, that is, the collision position distance of the sheet member 148 is as shown in Table 1 below. Changed to In each case, the value of h was set to the maximum value calculated by the above equation (1). The evaluation items are a collision sound when the sheet member 148 collides with the downstream side edge portion 146b of the opening 146, and permanent deformation of the sheet member 148. Table 1 shows the results.

  The “collision sound” was evaluated in three stages: ○ (good), Δ (no problem in practical use), and x (poor). Further, “permanent deformation” was evaluated as follows. That is, as shown in FIG. 5D, the toner agitating / conveying member 149 is fixed at a position where the sheet member 148 is bent in contact with the end 146d of the downstream edge 146b of the opening 146, and left for one week. did. Thereafter, the toner stirring / conveying member 149 was rotated from the fixed position, and it was observed whether or not the free end 148a of the sheet member 148 was permanently deformed (sagging). The sheet member 148 is deformed so that the contact state with the inner wall surface (conveying surface) 144a of the toner container 144 can no longer be maintained as x (defect). △ (no problem in practical use), and no deformation occurred ◯ (good).

  From the results of Table 1 above, in order to reduce the impact sound as much as possible and prevent the permanent deformation of the sheet member 148 as much as possible, the following equation (2) is satisfied. It turns out that it is preferable.

  The shape of the opening 146 is not limited to that of the present embodiment. For example, the shape as shown in FIGS. 7A to 7C has the same effect as the present embodiment. That is, in the example shown in FIG. 7A, the overhanging portion that extends to the substantially flat partition 145 above the downstream edge 146 b of the opening 146 and extends downward at a substantially right angle after extending to the inner side of the toner container 144. 145b is provided. As a result, the end 146d of the downstream edge 146b of the opening 146 is projected toward the rotation axis 149a. In the example shown in FIG. 7B, the partition wall 145 on the downstream edge 146 b side of the opening 146 is inclined toward the inner side of the toner container 144. As a result, the end 146d of the downstream edge 146b of the opening 146 is projected to the rotation axis 149 side. Further, in the example shown in FIG. 7C, the upper edge of the downstream edge 146b of the opening 146 protrudes to the inner side of the toner container 144 from the partition 145 below the upstream edge 146a of the opening 146. The substantially flat partition wall 145 is provided with an extending portion 145 d that extends to the inside of the developing chamber 143. As a result, the end 146d of the downstream edge 146b of the opening 146 is projected toward the rotation axis 149a.

  As described above, according to the present exemplary embodiment, when the sheet member 148 of the toner agitating / conveying member 149 collides with the downstream edge 146b of the opening 146, the toner can be favorably conveyed into the developing chamber 143. . In addition, according to the present exemplary embodiment, it is possible to reduce a collision sound caused by the sheet member 148 of the toner stirring and conveying member 149 colliding with the downstream edge 146b of the opening 146.

Example 2
Next, another embodiment of the present embodiment will be described. Basic configurations of the image forming apparatus, the developing device, the process cartridge, and the like in this embodiment are the same as those in the first embodiment. Accordingly, elements having the same functions or configurations as those of the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  In Example 1, as shown in FIG. 4, the shape of the downstream edge 146 of the opening 146 is the same over substantially the entire region in the longitudinal direction of the developing device 104. However, the portion of the toner stirring / conveying member 149 that contacts the sheet member 148 at the downstream edge 146 b of the opening 146 may be a part of the developing device 104 in the longitudinal direction.

  FIG. 8 is a perspective view showing the vicinity of the opening 146 of the developing device 104 according to the present embodiment. In FIG. 8, the sheet member 148 of the toner stirring and conveying member 149 is in the opening 146. In this embodiment, the shape of the downstream edge 146b of the opening 146 has a portion where the sheet member 148 of the toner agitating / conveying member 149 collides and a portion where it does not collide. FIG. 9A shows a schematic cross section including the colliding portion, and FIG. 9B shows a schematic cross section including the non-collision portion.

  More specifically, in this embodiment, a plurality of overhanging portions 145e having a substantially L-shaped cross section are formed at intervals in the longitudinal direction of the developing device 104, like the overhanging portion 145a in the first embodiment. As a result, the end 146d of the downstream edge 146b of the opening 146 protrudes toward the rotation axis 149a. An end 146d on the inner side of the toner container 144 at the downstream edge 146b of the overhanging portion 145e contacts the sheet member 148. On the other hand, the end 146f on the inner side of the toner container 144 of the downstream edge 146b between the overhanging portion 145e and the overhanging portion 145e in the longitudinal direction of the developing device 104 does not contact the sheet member 148.

  In this embodiment, overhanging portions 145e, which are portions where the sheet member 148 of the toner agitating / conveying member 149 collides, are provided at three locations in the longitudinal direction of the developing device 104 (both ends and the center in the same direction). However, it is sufficient that there is at least one portion where the sheet member 148 collides. However, when the sheet member 148 of the toner agitating / conveying member 149 collides with the downstream edge 146b of the opening 146, the toner attached on the sheet member of the toner agitating / conveying member 149 is peeled off from the sheet member 148. It is sent to the developing chamber 143. In consideration of this function, it is preferable that the portion where the sheet member 148 collides is disposed symmetrically in the longitudinal direction of the developing device 104.

  As described above, according to the present embodiment, the same effects as those of the first embodiment can be obtained. In addition, in this embodiment, the portion of the downstream edge 146b of the opening 146 that is in contact with the sheet member 148 is a part in the longitudinal direction of the developing device 104, so that the material used can be reduced and the toner container 144 can be formed. Improvement of molding accuracy can be expected.

  As mentioned above, although this invention was demonstrated according to the specific Example, this invention is not limited to the above-mentioned Example. For example, in the above-described embodiment, the process cartridge is a cartridge in which the photosensitive member and the charging unit, the developing unit, and the cleaning unit serving as the process unit acting on the photosensitive unit are integrally formed. It is not limited to. The process cartridge that can be attached to and detached from the main body of the image forming apparatus is a cartridge in which at least one of a charging unit, a developing unit, and a cleaning unit including a developing unit as a process unit that acts on the photosensitive member, and the photosensitive member are integrated into a cartridge. I just need it. The developing device may be a developing cartridge that can be detachably attached to the main body of the image forming apparatus alone, or may not be detachable from the main body of the image forming apparatus.

101 Photosensitive drum 104 Developing device 146 Toner supply opening (opening)
143 Development chamber 144 Toner container 147 Support member 148 Sheet member 149 Toner stirring and conveying member

Claims (4)

A developer chamber in which a developer carrier for supporting a developer is disposed; a developer container in which a developer to be supplied to the developer chamber is stored; and the developer chamber disposed between the developer chamber and the developer container, A partition formed with an opening for communicating the developing chamber and the developer container, and the developer disposed inside the developer container, stirring the developer inside the developer container and passing through the opening. A developing device having a rotatable developer stirring and conveying member that conveys the developer from a container to the developing chamber;
The developer stirring / conveying member includes a support member that can rotate around a rotation axis, and is fixed to the support member and is arranged around the rotation axis on the outer side in the rotation radial direction of the developer stirring / transporting member than the support member. A flexible sheet member that can rotate, and has a predetermined width in each of a first direction parallel to the rotation axis and a second direction orthogonal to the first direction. A sheet member in which one end portion in the direction is fixed to the support member and the other end portion is a free end,
The sheet member has the free end until immediately before passing the upstream end which is the end on the inner side of the developer container at the upstream edge of the opening in the rotation direction of the developer agitating and conveying member. Immediately after the free end passes through the upstream end and is restored to its natural shape, it is bent downstream of the opening in the rotational direction. A downstream edge that is an inner edge of the developer container at a side edge,
The distance between the downstream end and the rotation axis is smaller than the distance between the upstream end and the rotation axis in the radial direction of rotation of the developer agitation transport member. A developing device. When it is assumed that the developer stirring and conveying member rotates while the sheet member remains in its natural state, the free end side of the fixing portion of the sheet member to the support member in the second direction The length from the fixed end that is an end to the free end is B, the length from the fixed end to the upstream end along the second direction is C, and the length along the second direction is When the length from the fixed end to the downstream end is D and the length from the upstream edge to the downstream edge in the opening is h, the relationship C <B is satisfied. And the following formulas (1) and (2),

The developing device according to claim 1, wherein:   A main body of an image forming apparatus, comprising: an image carrier on which an electrostatic image is formed by being supplied with a developer by the developing device, and an electrostatic image forming unit that forms an electrostatic image on the image carrier. The developing device according to claim 1, wherein the developing device is removable.   An electrostatic image forming means for forming an electrostatic image on the image carrier formed in a cartridge integrally with an image carrier on which an electrostatic image to be developed by supplying developer by the developing device is formed. The developing device according to claim 1, wherein the developing device is detachable from a main body of the image forming apparatus.

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