JP5539018B2 - Development device - Google Patents

Description

  The present invention relates to a developing device used in an image forming apparatus using an electrophotographic process.

  Conventionally, in an image forming apparatus using an electrophotographic process, an electrostatic latent image is formed on a photosensitive member (electrophotographic photosensitive member), and the electrostatic latent image is developed by a developing device using a developer. For example, a developing device that uses a non-magnetic one-component developer as a developer has a developing container that contains toner as a developer. The developing container is provided with a developing roller as a developer carrying member, a toner supply peeling roller as a developer supply peeling member, and a developing blade as a developer regulating member.

  FIG. 7 shows a cross section cut along a plane including the rotation axis of the developing roller 141 and the rotation axis of the toner supply stripping roller 142 in the conventional developing device, and FIG. 8 shows the development cut at the position B1-B1 in FIG. A cross section of the device is shown.

  As shown in FIGS. 7 and 8, the developing container is provided with a seal member for preventing leakage of the developer from the inside thereof. First, the toner leakage prevention sheet 146 as a seal member contacts the developing roller 141 along the longitudinal direction of the developing roller 141 over substantially the entire length of the developing roller 141 to prevent toner from leaking from the inside of the developing container 140. . Further, the end seal member 147 as a seal member contacts the developing roller 141 in an arc shape at the end in the longitudinal direction of the developing roller 141 to prevent the toner from leaking from the inside of the developing container 140.

  Thus, conventionally, an end seal 147 that contacts the outer peripheral surface of the rotating developing roller 41 and prevents toner from leaking from the inside of the developing container 140 is provided at the end in the longitudinal direction of the developing roller 141. . As the end seal 147, for example, a fibrous material having high slipperiness is used (Patent Document 1).

  In addition, a gap is provided between the end surface of the toner supply stripping roller in the longitudinal direction and the inner wall of the developing container, and the toner is allowed to escape through the gap so that the toner powder is near the end of the developing roller in the longitudinal direction. It has been proposed to prevent the pressure from increasing (Patent Document 2). Thereby, it is possible to prevent the end seal from being deformed by the powder pressure of the toner and the toner from leaking from the inside of the developing container.

Japanese Patent Laid-Open No. 5-40402 JP-A-5-35069

  However, in the configuration in which a gap is provided between the end surface of the toner supply peeling roller and the inner wall of the developing container, there is a region where the toner supply peeling roller does not come into contact with the end portion in the longitudinal direction of the developing roller. The toner on the developing roller in this region is not stripped by the toner supply stripping roller. For this reason, in this part of the developing roller, the same toner does not circulate with the toner inside the developing container, but is repeatedly conveyed to a portion (developing area) facing the photoconductor, thereby deteriorating the toner. It becomes easy. In some cases, the toner coat amount in this portion increases, and it becomes impossible to impart sufficient charge to the toner. Therefore, toner that does not have sufficient charge may be generated, and fogging (a phenomenon in which toner adheres to a non-image portion where toner should not adhere) may occur.

  Even when the gap is arranged at a position facing the outside of the developing roller area (image forming area) facing the image formable area on the photoconductor, the toner deteriorated as described above is not removed from the image forming area. A similar problem can occur when moving to.

  Accordingly, an object of the present invention is to provide a developing device capable of preventing the developer from deteriorating due to the provision of a gap between the developer supply stripping member and the inner wall of the developing container. is there.

The above object is achieved by the developing device according to the present invention. In summary, the present invention relates to a rotatable developer carrier that carries and transports a developer and supplies the developer to an electrostatic latent image; and forms a contact region in contact with the developer carrier. A rotatable developer supply stripping member for supplying a developer to the developer carrier and stripping the developer from the developer carrier , the surface layer comprising a foam layer, and the developer carrier A developer supply stripping member that is compressed in contact with the outer periphery and rotates so that the moving direction of the outer peripheral surface in the contact region is opposite to the moving direction of the outer peripheral surface of the developer carrier ; A developer container that supports the developer carrying member and the developer supply stripping member and accommodates the developer; and between the end surface of the end of the developer supply stripping member in the rotation axis direction and the inner wall of the developer container Arranged in the gap, stripping off the developer supply Material of the outer peripheral surface of said developer carrying member is not in contact, in extended area in the rotation axis direction of the contact region and the developer carrying member, always in contact with the developer bearing member rotates, rotates wherein an end portion scraping member stripping the developer from the developer carrying member; have a; the end stripping member is in the gap, the contact between the developer carrier and the end stripping member The developing device is characterized by being arranged so as to partition the upstream side and the downstream side in the moving direction of the outer peripheral surface of the developer supply stripping member with respect to the position .

  According to the present invention, it is possible to prevent the developer from deteriorating due to the provision of a gap between the developer supply stripping member and the inner wall of the developing container.

1 is a longitudinal sectional view of an image forming apparatus according to an embodiment of the present invention. It is a longitudinal cross-sectional view of the process cartridge in one Example of this invention. FIG. 4 is a cross-sectional view taken along a plane including the rotation axis of the developing roller and the rotation axis of the toner supply peeling roller of the developing device according to the embodiment of the present invention. FIG. 4 is a cross-sectional view of the developing device taken along the line A2-A2 in FIG. 3. FIG. 4 is a cross-sectional view of the developing device taken along the line A3-A3 in FIG. 3. FIG. 4 is a cross-sectional view of the developing device taken along the line A4-A4 in FIG. 3. FIG. 6 is a cross-sectional view taken along a plane including a rotation axis of a developing roller and a rotation axis of a toner supply peeling roller in an example of a conventional developing device. FIG. 8 is a cross-sectional view of the developing device taken along the line B1-B1 in FIG. 7.

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

Example 1
1. First, an overall configuration and operation of an image forming apparatus according to an embodiment of the present invention will be described. FIG. 1 shows a longitudinal section of an image forming apparatus 10 of this embodiment. In this embodiment, the image forming apparatus 10 is a tandem type laser beam printer that can form a full-color image using an electrophotographic system.

  The image forming apparatus 10 includes first, second, third, and fourth image forming units PY, PM, PC, and PK as a plurality of image forming units. The first, second, third, and fourth image forming units PY, PM, PC, and PK form yellow (Y), magenta (M), cyan (C), and black (K) images, respectively. To do. In the present embodiment, the configurations and operations of the first, second, third, and fourth image forming units PY, PM, PC, and PK have many common parts. Accordingly, in the following, when there is no need for distinction, the subscripts Y, M, C, and K given to the reference numerals in the drawing will be omitted in order to indicate that they are elements for any color, and the description will be made comprehensively.

  The image forming unit P includes a cylindrical photosensitive member (electrophotographic photosensitive member), that is, a photosensitive drum 1 as an image carrier. The photosensitive drum 1 is rotationally driven in the arrow R1 direction. The photosensitive drum 1 has a photosensitive material layer formed on the surface of a cylindrical substrate. In this embodiment, the cylindrical substrate of the photosensitive drum 1 is made of aluminum, and the photosensitive material layer is an organic photosensitive material layer.

  Around the photosensitive drum 1, the following units are arranged in order along the rotation direction. First, a charging roller 2 as a charging unit. Next, there is a laser beam scanning optical system 3 as exposure means. Next, there is a developing device 4 as a developing unit. Next, a transfer roller 5 as a transfer unit. Next, there is a cleaner 6 as a cleaning means.

  Further, an endless belt-like transport belt 7 as a recording material carrier is disposed so as to face the photosensitive drums 1Y, 1M, 1C, and 1K of the image forming units PY, PM, PC, and PK. The conveyor belt 7 is stretched by a driving roller 71, a driven roller 72, and tension rollers 73 and 74. The conveyance belt 7 rotates (circulates) in the direction of the arrow R <b> 2 when a rotational driving force is transmitted to the driving roller 71. The transfer rollers 5Y, 5M, 5C, and 5K are disposed on the inner peripheral surface side of the conveyor belt 7. Then, the transfer rollers 5Y, 5M, 5C, and 5K are pressed against the photosensitive drums 1Y, 1M, 1C, and 1K via the conveyance belt 7, respectively, so that the transfer rollers 5Y, 5M, 5C, and 5K are conveyed with the photosensitive drums 1Y, 1M, 1C, and 1K. Transfer portions TY, TM, TC, and TK in contact with the belt 7 are formed.

  In this embodiment, the photosensitive drum 1 and the charging roller 2, the developing device 4, and the cleaner 6 as process means acting on the photosensitive drum 1 are integrally formed into a cartridge and attached to and detached from the apparatus main body of the image forming apparatus 10. The process cartridge 8 is possible. FIG. 2 shows a longitudinal section of the process cartridge 8 of the present embodiment.

For example, an image forming operation will be described taking a case of forming a full-color image as an example. First, the photosensitive drum 1 is uniformly charged by the charging roller 2. The charged surface of the photosensitive drum 1 is exposed by the laser beam scanning optical system 3 according to the image information of the color component corresponding to each image forming portion P. Thereby, an electrostatic latent image (electrostatic image) according to the image information of the color component corresponding to each image forming portion P is formed on the photosensitive drum 1. The electrostatic latent image formed on the photosensitive drum 1 is developed as a toner image by the developing device 4 using toner as a developer.

  In this embodiment, the developing device 4 has the same charge polarity (negative polarity in this embodiment) as that of the photosensitive drum 1 on the exposed portion of the surface of the photosensitive drum 1 that has been uniformly charged. The electrostatic latent image is developed by reversal development in which polar toner is attached. Further, as will be described in detail later, in this embodiment, the developing device 4 develops the electrostatic latent image by a contact development method using a toner that is a nonmagnetic one-component developer as a developer.

  On the other hand, the recording material S such as recording paper or OHP sheet is fed from the cassette 11 by the recording material supply roller 12 and the registration roller 13 in synchronism with the formation of the toner image on the photosensitive drum 1 in each image forming portion P. Then, it is conveyed to the conveyor belt 7. The recording material S is electrostatically attracted onto the rotating conveyance belt 7 and is sequentially conveyed to each transfer unit T of each image forming unit P. In the process, the toner image formed on each photosensitive drum 1 of each image forming unit P is sequentially superimposed on the recording material S on the conveyance belt 7 by the action of each transfer roller 5 in each transfer unit T. It will be transcribed. At this time, a transfer bias that is a voltage having a polarity opposite to the normal charging polarity of the toner (positive polarity in this embodiment) is applied to each transfer roller 5.

  The recording material S to which the toner image has been transferred is separated from the conveyance belt 7 and conveyed to a fixing device 9 as a fixing unit. The fixing device 9 includes a fixing roller 91 having a heat source and a pressure roller 92 that is in pressure contact with the fixing roller 91, and the recording material S is sandwiched and conveyed by the pair of rollers to record an unfixed toner image. Fix (fix) to the surface of the material S. The recording material S on which the toner image is fixed is discharged to a tray 14 provided on the upper part of the main body of the image forming apparatus 10.

  The toner (transfer residual toner) remaining on the photosensitive drum 1 after the transfer process is removed from the photosensitive drum 1 by the cleaner 6 and collected. That is, in this embodiment, the cleaner 6 includes a cleaning blade 61 as a cleaning member that contacts the surface of the photosensitive drum 1 and a waste toner container 62. The cleaner 6 scrapes off the transfer residual toner from the surface of the rotating photosensitive drum 1 by the cleaning blade 61 and collects it in the waste toner container 62.

  When forming a monochrome image, a toner image is formed only in the fourth image forming unit PK among the first, second, third, and fourth image forming units PY, PM, PC, and PK. Is transferred to the recording material S and fixed.

2. Next, the developing device 4 of this embodiment will be further described. As shown in FIG. 2, the developing device 4 includes a developing container (frame body) 40 that accommodates toner that is a nonmagnetic one-component developer as a developer. An opening is provided in a portion of the developing container 40 that faces the photosensitive drum 1, and a developer is carried, conveyed, and supplied to the photosensitive drum 1 so as to be partially exposed from the opening. A developing roller 41 as a carrier is provided. The developing roller 41 is in contact with the photosensitive drum 1 and is rotationally driven so that the direction of the arrow R3, that is, the moving direction of the surface at the contact portion with the photosensitive drum 1 is the forward direction with the moving direction of the surface of the photosensitive drum 1. Is done. Both ends of the developing roller 41 in the longitudinal direction (rotational axis direction) are rotatably supported by the developing container 40. In this embodiment, the developing roller 41 is an elastic multi-layer roller having an elastic layer composed of a base layer and a surface layer around a metal core, and urethane rubber is used as the base layer and carbon is used as the surface layer above the base layer. Mixed urethane rubber was used. However, the configuration of the developing roller 41 is not limited to this, and the elastic layer may be a single layer, or may be composed of ether urethane or nylon.

Further, the developer container 40 is provided with a toner supply peeling roller 42 as a developer supply peeling member for supplying the developer to the developing roller 41 and peeling the developer from the developing roller 41. The toner supply / peeling roller 42 contacts the developing roller 41, and the direction of movement of the surface in the direction of arrow R 4, that is, the contact portion with the developing roller 41 is opposite to the direction of movement of the surface of the developing roller 41 (counter Direction). Both ends of the toner supply / peeling roller 42 in the longitudinal direction (rotation axis direction) are rotatably supported by the developing container 40. In this embodiment, the toner supply stripping roller 42 is an elastic roller provided with an elastic foam, particularly a sponge roller in which urethane foam as a foam layer is provided on the outer periphery of a metal cored bar. However, the material of the core metal and the foam layer of the toner supply peeling roller 42 is not limited to this, and it is sufficient that at least the outer peripheral portion in contact with the developing roller 41 is made of sponge. The toner supply peeling roller 42 enters and contacts the developing roller 41 with a predetermined intrusion amount (1 mm in this embodiment), and is compressed at the corresponding contact portion. Thus, between the developing roller 4 1 and the toner supply stripping roller 42, a predetermined width of the surface moving direction of the toner scraping supply roller 42 from the contact start position of the upstream side to the contact end of the downstream side Nip (contact area) (hereinafter referred to as “contact nip”) N is formed.

  The photosensitive drum 1, the developing roller 41, and the toner supply / peeling roller 42 are arranged so that their rotational axes are substantially parallel to each other. A contact nip N between the developing roller 41 and the toner supply peeling roller 42 extends substantially parallel to the rotation axis direction of the developing roller 41 and the toner supply peeling roller 42. As will be described in detail later, in this embodiment, the length of the toner supply stripping roller 42 in the longitudinal direction is shorter than the length of the developing roller 41 in the longitudinal direction, and the developing roller 41 supplies toner in the longitudinal direction. The peeling roller 42 extends outward from both ends.

  Further, the developing container 40 is provided with a developing blade 43 that is a plate-like member formed of an elastic body as a developer regulating member that regulates the amount of developer carried on the developing roller 41. The developing blade 43 is located downstream of the contact portion between the developing roller 41 and the toner supply stripping roller 42 in the surface movement direction of the developing roller 41 and upstream of the contact portion between the developing roller 41 and the photosensitive drum 1. The developing roller 41 is in contact with the developing roller 41. In this embodiment, the developing blade 43 is supported by the developing container 40 so that the free end faces the upstream side in the surface movement direction of the developing roller 41 and one side surface contacts the developing roller 41. The toner on the developing roller 41 is regulated in layer thickness by the developing blade 43 and is charged by friction.

  FIG. 3 shows a cross section (cross section taken along line A1-A1 in FIG. 2) taken along a plane including the rotation axis of the developing roller 41 and the rotation axis of the toner supply peeling roller 42 in the developing device 4 of this embodiment. 4 shows a cross section of the developing device 4 taken along the line A2-A2 in FIG. 3, FIG. 5 shows the line A3-A3 in FIG. 3, and FIG. 6 shows the line A4-A4 in FIG.

  As shown in FIGS. 3 and 6, the developing container 40 is provided with a seal member that prevents leakage of the developer from the inside thereof. First, the toner leakage prevention sheet 46 as a seal member is in contact with the developing roller 41 along the longitudinal direction of the developing roller 41 over substantially the entire longitudinal direction to prevent the toner from leaking from the inside of the developing container 40. . The toner leakage prevention sheet 46 is supported on the edge of the opening of the developing container 40 on the downstream side in the surface movement direction of the developing roller 41. Further, the end seal member 47 as a seal member contacts the developing roller 41 in an arc shape at the longitudinal end of the developing roller 41 to prevent the toner from leaking from the inside of the developing container 40. The end seal 47 is fixed to the arcuate wall surface of the developing container 40 that faces the end of the developing roller 41. The end seals 47 are provided on both end sides in the longitudinal direction of the developing roller 41 and have substantially the same configuration. As described above, the end seal 47 that contacts the outer peripheral surface of the rotating developing roller 41 and prevents the toner from leaking from the inside of the developing container 40 is provided at the end in the longitudinal direction of the developing roller 41. As the end seal 47, in order to prevent the toner from leaking from the inside of the developing container 40 without damaging the developing roller 41, a fibrous material having a high slip property can be suitably used. In this embodiment, as the end seal 47, a felt made of Teflon (registered trademark of Polytetrafluoroethylene DuPont) was used.

  In the present embodiment, the inside of the developing container 40 is partitioned into a toner storage portion 40A and a toner storage portion 40B by a partition wall 40C having an opening 40C1. The developing roller 41, the toner supply stripping roller 42, the developing blade 43, and the like are disposed in the toner storage unit 40A, and a toner transport blade 45 that is rotationally driven as a developer transport unit is disposed in the toner storage unit 40B. Has been.

  At the time of image formation, toner is supplied to the surface of the rotationally driven developing roller 41 by a toner supply and peeling roller 42 that is rotationally driven in the counter direction with respect to the developing roller 41. The toner coat amount on the surface of the developing roller 41 is controlled by the developing blade 43. The developing roller 41 carrying toner contacts the photosensitive drum 1 while rotating. At this time, a predetermined developing bias is applied to the developing roller 41, and an electric field formed between the developing roller 41 and the photosensitive drum 1 causes an electrostatic latent image formed on the photosensitive drum 1. The toner is transferred from the developing roller 41 to the photosensitive drum 1. As a result, a toner image is formed on the photosensitive drum 1.

  Toner remaining on the developing roller 41 without being used to form a toner image passes through the toner leakage prevention sheet 46 and is peeled off by the toner supply peeling roller 42. Further, toner is newly supplied onto the developing roller 41 by a toner supply and peeling roller 42. Thus, the toner supplied to the developing roller 41 circulates while being sequentially replaced with the toner inside the toner storing portion 40A of the developing container 40. As the image forming operation is repeated, the toner in the toner storage unit 40A is consumed.

  The toner conveying means 45 operates constantly or in a timely manner and sends the toner inside the toner storage unit 40B to the toner storage unit 40A. Further, the toner overflowing from the toner storage unit 40A returns to the toner storage unit 40B. As a result, the toner is circulated and stirred inside the developing container 40.

  Next, with reference to FIG. 4, the operation of the toner supply peeling roller 42 will be described in more detail along the movement in the rotation direction. In the present embodiment, as described above, the toner supply stripping roller 42 uses a sponge-like elastic member having a plurality of cells on the outer peripheral portion. When the toner supply peeling roller 42 contacts the developing roller 41 and the outer peripheral cells are crushed, the toner contained in the toner supply peeling roller 42 is discharged, and a part of the discharged toner is discharged. Supplied on the developing roller 41. At this time, a relatively positive pressure region is generated in the vicinity of the inlet of the upstream contact nip N in the surface movement direction of the toner supply peeling roller 42, and the toner flow indicated by the arrow in the drawing is thereby generated. It is formed. Further, the toner supply stripping roller 42 strips off the residual toner on the developing roller 41 at the contact nip N. Then, when the toner supply peeling roller 42 moves away from the developing roller 41, the crushed cell is released and opened, and at that time, air is sucked toward the cell. Thereby, the toner peeled off from the developing roller 41 and the toner around the toner supply peeling roller 42 are sucked toward the toner supply peeling roller 42. Further, the toner supply / peeling roller 42 rotates and conveys the toner inside the toner reservoir 40 </ b> A while being rolled up, and is supplied to the next developing roller 41. At this time, a relatively negative pressure region is generated in the vicinity of the outlet of the contact nip N on the downstream side in the surface movement direction of the toner supply stripping roller 42, and this causes the toner flow indicated by the arrows in the figure. It is formed.

  In this embodiment, as shown in FIG. 3, a predetermined amount of gap is provided between the end surface 42a at the end of the toner supply stripping roller 42 in the longitudinal direction and the inner wall 40a of the developing container 40 facing the end surface 42a. Is provided. In this embodiment, this gap (distance in the longitudinal direction of the developing roller 41) is 1 mm. In this embodiment, the gap is provided at the same position at the opposite positions of both ends in the longitudinal direction of the toner supply peeling roller 42.

  In this embodiment, the gap is arranged at a position facing the outside of the developing roller 41 (image forming area) facing the image forming area on the photosensitive drum 1.

Thus, by providing the gap and allowing the toner to escape through the gap, it is possible to prevent the toner powder pressure from increasing in the vicinity of the end of the developing roller 41 in the longitudinal direction. Accordingly, it is possible to prevent the end seal 47 from being deformed by the powder pressure of the toner and causing the toner to leak from the inside of the developing container 40. Further, by providing the gap, it is possible to prevent the end seal 47 from being caught by rotation of the toner supply peeling roller 42. Particularly, in the case of using the end seal 4 7 fibrous, when it is caught in the take-up roller 42 peeling the toner supply, there is a possibility of causing a defect torn. On the other hand, by providing the gap as in this embodiment, it is possible to prevent the fibers of the end seal 47 from being caught in the toner supply peeling roller 42. It is possible to prevent tearing.

  However, if a gap is provided between the end surface 42 a of the toner supply peeling roller 42 and the inner wall 40 a of the developing container 40, the toner on the developing roller 41 is not peeled off by the toner supply peeling roller 42 at this portion. For this reason, in this part of the developing roller 41, the same toner is not circulated with the toner inside the developing container 40, but is repeatedly conveyed to the portion (developing region) facing the photosensitive drum 1, thereby the toner. Tends to deteriorate. In some cases, the toner coat amount in this portion increases, and it becomes impossible to impart sufficient charge to the toner. Therefore, toner that does not have sufficient charge may be generated, and fogging may occur.

  One of the purposes of this embodiment is to provide a gap between the end surface 42a of the toner supply stripping roller 42 and the inner wall 40a of the developing container 40 while preventing toner leakage and the end seal 47 from being caught. Thus, the toner is prevented from deteriorating. Another object of the present embodiment is to prevent fogging in a region where the toner supply peeling roller 42 is not in contact with the developing roller 41.

  Therefore, in the present embodiment, as shown in FIGS. 3 and 5, the developing roller on the extension line of the contact nip N in the region between the end surface 42 a of the toner supply stripping roller 42 and the inner wall 40 a of the developing container 40. An end stripping member 48 that contacts the surface (outer peripheral surface) of 41 is provided. In this embodiment, end stripping members 48 having the same configuration are provided at both ends in the longitudinal direction of the toner stripping supply roller 42. If desired, the end stripping member 48 may be provided only at one end in the longitudinal direction of the toner supply stripping roller 42.

  In the present embodiment, the end stripping member 48 has a contact portion 48a that contacts the surface (outer peripheral surface) of the developing roller 41 and a support portion 48b that supports the contact portion 48a. In the present embodiment, the contact portion 48a is a plate-like member (blade) formed of an elastic body, and in particular, in this embodiment, is formed of urethane rubber. The abutting portion 48 a has a free end edge on the surface of the developing roller 41 in a region where the abutting nip N is extended in the longitudinal direction of the developing roller 41, and the free end is in the surface moving direction of the developing roller 41. They are arranged in contact with each other so as to face the upstream side. Further, in this embodiment, the support portion 48b includes an annular portion 48b1 fitted to the rotation shaft 42b at the end portion in the longitudinal direction of the toner supply peeling roller 42, and a radial direction of the toner supply peeling roller 42 from the annular portion 48b1. And a mounting portion 48b2 of the abutting portion 48a extending in the direction. The support 48 b is retracted inward from the outer peripheral surface of the toner supply peeling roller 42 in the radial direction of the toner supply peeling roller 42. Except for the portion where the contact portion 48a is in contact with the surface of the developing roller 41, a gap is still provided between the end surface 42a of the toner supply stripping roller 42 and the inner wall 40a of the developing container 40. Yes. That is, above and below the contact portion 48 a, the surface of the developing roller 41 communicates directly with the gap between the end surface 42 a of the toner supply stripping roller 42 and the inner wall 40 a of the developing container 40. Accordingly, the effect of preventing the toner powder pressure from being increased by the gap is not disturbed.

  The toner remaining on the surface of the end portion in the longitudinal direction of the developing roller 41 where the toner supply peeling roller 42 does not contact after passing through the facing portion between the photosensitive drum 1 and the developing roller 41 passes through the toner leakage prevention sheet 46. . Then, the toner is peeled off inside the developing container 40 by the end stripping member 48. In addition, the toner supply and peeling roller 42 is not in contact with this portion, but new toner is supplied by moving from the contact nip N along the peripheral surface of the developing roller 41. Therefore, it is possible to prevent the same toner from being repeatedly conveyed to the facing portion between the photosensitive drum 1 and the developing roller 41.

  Further, the end stripping member 48 is disposed so as to come into contact with the developing roller 41 on the extension line of the contact nip N and strip off the toner. Therefore, the positive pressure region generated by the toner discharging portion from the toner supply peeling roller 42 and the negative pressure region generated by the toner suction portion into the toner supply peeling roller 42 are peeled off at the end. It is partitioned by a member 48. Thus, the toner discharged from the toner supply peeling roller 42 in the positive pressure area is directly sucked in the negative pressure area through the gap between the end surface 42a of the toner supply peeling roller 42 and the inner wall 40a of the developing container 40. It will never be. Further, the toner peeled off from the developing roller 41 by the end stripping member 48 is drawn by the negative pressure generated by the inner toner supply stripping roller 42 in the longitudinal direction of the developing roller 41. The drawn toner is sucked into the toner supply stripping roller 42 and conveyed. As a result, the toner peeled off from the developing roller 41 does not stay near the end of the developing roller 41 in the longitudinal direction. Therefore, the toner at the end in the longitudinal direction of the developing roller 41 can be circulated between the toner in the developing container 40 in the same manner as the toner in the image forming area at the center in the same direction. For this reason, it is possible to prevent the toner from deteriorating due to the same toner being repeatedly conveyed to the facing portion between the photosensitive drum 1 and the developing roller 41.

  In this embodiment, the portion of the end stripping member 48 that contacts the developing roller 41 is made of urethane rubber, but the present invention is not limited to this. For example, the portion of the end stripping member 48 that contacts the developing roller 41 may be made of nylon or other material.

  As described above, due to the effect of the end stripping member 48, the toner deteriorates due to the provision of a gap between the end surface 42a of the toner supply stripping roller 42 and the inner wall 40a of the developing container 40. Can be prevented. In addition, this can prevent fogging in a region where the toner supply peeling roller 42 is not in contact with the developing roller 41.

  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 developing device is described as being detachable from the apparatus main body of the image forming apparatus as a process cartridge. However, the present invention is not limited to this. The unit corresponding to the developing device in the above-described embodiment may be a developing cartridge that can be detachably attached to the main body of the image forming apparatus. The process cartridge is a cartridge in which an electrophotographic photosensitive member and at least one process means acting on the electrophotographic photosensitive member are integrated. Examples of the process means include a charging means, a developing means, and a cleaning means that act on the electrophotographic photosensitive member. In particular, the developing means in the present invention includes a developer carrier, a developer supply stripping member, an end seal member, and an end stripping member.

  In the above-described embodiments, the image forming apparatus is described as a laser beam printer. However, the present invention is not limited to this. Here, the electrophotographic image forming apparatus forms an image on a recording medium using an electrophotographic image forming process. 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.

DESCRIPTION OF SYMBOLS 1 Photosensitive drum 2 Charging roller 4 Developing apparatus 41 Developing roller 42 Toner supply peeling roller 47 End seal member 48 End strip member

Claims (7)

A rotatable developer carrying member carrying and carrying the developer and supplying the developer to the electrostatic latent image;
Wherein a developer supply stripping member rotatable peeling off the developer from the developer carrier with contact with the developer carrying member to form a contact region for supplying the developer to said developer carrying member, The surface layer is composed of a foam layer, and is compressed in contact with the developer carrying member, and the moving direction of the outer peripheral surface in the contact region is opposite to the moving direction of the outer peripheral surface of the developer carrying member. A developer supply stripping member that rotates to be
A developer container for supporting the developer carrying member and the developer supply stripping member and containing the developer;
An outer periphery of the developer carrier that is disposed in a gap between an end surface of the developer supply stripping member in the rotation axis direction and an inner wall of the developer container and is not in contact with the developer supply stripping member surface, in extended area in the rotation axis direction of the contact region and the developer carrying member, wherein always in contact with the developer bearing member rotates, end stripping the developer from said developer carrying member rotates A stripping member;
I have a,
In the gap, the end stripping member is located upstream and downstream in the movement direction of the outer peripheral surface of the developer supply stripping member with respect to the contact position between the end stripping member and the developer carrier. A developing device, wherein the developing device is arranged so as to partition the side .   The end stripping member has a plate-like member formed of an elastic body that is a contact portion that comes into contact with the outer peripheral surface of the developer carrying member, and the plate-like member has a free end at the developer. 2. The developing device according to claim 1, wherein the developing device is in contact with the developer carrying member so as to face an upstream side in a moving direction of an outer peripheral surface of the carrying member. A seal member that contacts an outer peripheral surface of an end portion of the developer carrier in the rotation axis direction and prevents the developer inside the developer container from leaking from the end portion of the developer carrier; The part peeling member is a gap between the inner wall of the developer container inside the seal member in the rotation axis direction of the developer carrier and the end surface of the end of the developer supply peeling member in the rotation axis direction. the developing device according to claim 1 or 2, characterized in that disposed. The end stripping member includes a contact portion that contacts the outer peripheral surface of the developer carrying member, and a support portion that fits the rotation shaft of the developer supply stripping member while supporting the corresponding contact portion. an apparatus according to any one of claims 1-3, characterized in that it has. The developing device according to any one of claims 1-4, characterized in that it is detachably mountable to the apparatus main body of the image forming apparatus. 6. The developing device according to claim 5 , wherein the developing device is integrally formed with a photosensitive member on which the electrostatic latent image is formed, and is detachable from the apparatus main body.   The developing device according to claim 1, wherein the developer is a one-component developer.

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