JP2010054979A - Developing device, process cartridge, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a developing device and process cartridge that suppress image noise, filming, and so on while preventing a developer leak. <P>SOLUTION: The developing device 5 includes: a developer carrier 52 that is rotatable within a developing case 51 and supplies developer to an image carrier 1; a rotatable developer recovery member 53 that recovers developer from the developer carrier 52; a sheet member 2 that is disposed in contact with the developer carrier within the developing case; and an elastic member 54 that elastically brings the sheet member into contact with the developer carrier, opposite a contact face 2A with the developer carrier. One end 2a of the sheet member, which is located further inside the developing case than the contact part A with the developer carrier is disposed further away from the developer carrier than a tangent G of the sheet member 2 and the surface 52a of the developer carrier 52. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a developing device that develops a latent image using a developer, a process cartridge, and an image forming apparatus including these.

  An electrophotographic image forming apparatus develops a latent image formed on an image carrier with a developer in a developing device. There are two types of developing devices, one that is mounted on the image forming apparatus main body alone, and the other that is integrated with the image carrier and is detachably mounted on the image forming apparatus main body as a process cartridge.

  The developing device includes a developer carrying member such as a rotatable developing sleeve for supplying toner to an image carrier such as a photosensitive member, and a developer carrying member in a developing case containing toner as a one-component developer. A rotatable developer collecting member for collecting toner from the toner, and a layer thickness regulating member such as a blade for regulating the layer thickness of the toner supplied to the image carrier. The developing device rotates the developer carrier to supply toner to the image carrier, and rotates the developer recovery member to peel off the remaining toner from the developer carrier without being consumed for development. It is collected by that.

  In the developing device, a sheet member is disposed for the purpose of preventing leakage of the developer from the lower part of the developing case. This sheet member is flexible. For example, in Patent Documents 1 to 3, one end of the sheet member is brought into light pressure contact with the developer carrying member in the developing case, and the other end is fixed to the developing case. The toner remaining on the carrier is allowed to pass and the toner in the developing case is prevented from leaking out from the lower portion of the developing case.

  In Patent Document 4, in order to press the sheet member against the developer carrier, an elastic member is arranged on the opposite side of the sheet member from the contact surface with the developer carrier, and the sheet member is placed against the developer carrier. In elastic contact.

JP-A-5-72884 Japanese Patent Laid-Open No. 11-344859 Japanese Patent Laid-Open No. 11-174816 JP-A-11-219032

  In the case of a configuration in which the sheet member as in Patent Documents 1 to 3 is pressed against the developer carrier alone, the sheet member is pressed against the developer carrier by its bending, and therefore concentrated on one place of the developer carrier. Pressure is applied. For this reason, the toner remaining on the developer carrying member is easily fixed at the contact portion with the sheet member, which causes generation of toner deterioration, toner filming on the surface of the developer carrying member, and the like.

  In the configuration of Patent Document 4, since the bending of the elastic member is used to press the sheet member against the developer carrier, the pressure is dispersed and applied to the whole, so that the contact portion between the developer carrier and the sheet member is applied. Residual toner is hard to stick. However, since the elastic member is crushed and deformed along the outer peripheral surface of the developer carrying member, one end of the sheet member located in the case is also closer to the outer periphery of the developer carrying member than the contact portion between the developer carrying member and the sheet member. It deforms along the surface. Thus, when one end of the sheet member located in the case is deformed along the outer peripheral surface of the developer carrying member, the residual toner that has passed through the contact portion tends to stay on one end side, resulting in poor recovery from the developer carrying member. It becomes a factor. Such poor toner collection causes the undeveloped toner to gradually accumulate on the developer carrier, making it impossible to form a sufficient toner layer, and causes image noise and filming.

  An object of the present invention is to provide a developing device and a process cartridge that suppress the occurrence of image noise and filming while preventing leakage of the developer.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming apparatus capable of obtaining a good image by suppressing the occurrence of image noise and filming in a development system.

  To achieve the above object, according to claim 1, a developer carrier that is rotatable in a developing case and that supplies a developer to an image carrier, and a rotation that collects the developer from the developer carrier. A possible developer recovery member, a sheet member in contact with the developer carrier in the development case, and the sheet member on the opposite side of the contact surface with the developer carrier on the sheet member with respect to the developer carrier In the developing device provided with the elastic member to be elastically contacted, one end of the sheet member positioned in the developing case rather than the contact portion with the developer carrier is more than the tangent line between the sheet member and the developer carrier. It is characterized by being arranged in a direction away from the developer carrying member.

  In the developing device according to the present invention, one end of the sheet member located in the developing case rather than the contact portion with the developer carrier is separated from the developer carrier than the tangent line between the sheet member and the developer carrier. It is characterized by being fixed in the direction.

  The developing device according to the present invention is characterized in that one end of the sheet member located in the developing case rather than the contact portion with the developer carrying member is disposed so as to contact the developer collecting member.

  In the developing device according to the present invention, the other end of the sheet member located on the opposite side to the one end of the sheet member is not fixed.

  In the developing device according to the present invention, the sheet member is conductive.

  In the developing device according to the present invention, the sheet member functions as a charge eliminating member when a voltage is applied thereto.

  In the developing device according to the present invention, the sheet member is applied with the same voltage as the developer carrying member.

  In the developing device according to the present invention, the sheet member is formed of a material that frictionally charges the developer to the positive charging side or a material that frictionally charges the developer to the reverse charging side.

  A process cartridge according to the present invention, which includes at least an image carrier and a developing device and is detachable from the main body of the image forming apparatus, has any of the developing devices described above as a developing device.

  An image forming apparatus according to the present invention includes the developing device or the process cartridge.

  According to the present invention, the elastic member provided on the side opposite to the contact surface with the developer carrier is more elastic than the contact portion with the developer carrier of the sheet member that elastically contacts the developer carrier. Since one end located in the developing case is arranged in a direction away from the developer carrying body with respect to the tangent line between the sheet member and the developer carrying body, the residual toner that has passed through the sheet member is less likely to stay and the developing case It becomes easy to return inside. For this reason, residual toner is not gradually accumulated on the developer carrying member due to poor collection, and a sufficient toner layer can be formed, and image noise and filming can be suppressed.

  According to the present invention, one end of the sheet member positioned in the developing case rather than the contact portion with the developer carrying member is separated from the developer carrying member with respect to the tangent line between the sheet member and the developer carrying member. Since it is fixed, one end is stabilized at a position away from the developer carrying member, and the residual toner that has passed through the sheet member surely falls into the case. For this reason, residual toner is not gradually accumulated on the developer carrying member due to poor collection, and a sufficient toner layer can be formed, and image noise and filming can be further suppressed.

  According to the present invention, since the one end of the sheet member located in the developing case rather than the contact portion with the developer carrying member is disposed so as to contact the developer collecting member, the developer collecting member rotates. Therefore, the residual toner that has passed through the sheet member surely falls into the case. For this reason, residual toner is not gradually accumulated on the developer carrying member due to poor collection, and a sufficient toner layer can be formed, and image noise and filming can be further suppressed.

  According to the present invention, since the other end of the sheet member located on the opposite side to the one end of the sheet member is not fixed, it is difficult to leak from the other end side as compared with the case where the other end is fixed to the developing case.

  According to the present invention, when the sheet member is conductive or the sheet member functions as a charge removal member when a voltage is applied to the sheet member, the residual toner on the developer carrier is adsorbed to the sheet member side. Therefore, the collection efficiency is improved, and image noise and filming can be further suppressed.

  According to the present invention, since the sheet member functions as a charge eliminating member when the same voltage as that applied to the developer carrying member is applied to the sheet member, the residual toner on the developer carrying member is adsorbed to the sheet member side. Recovery efficiency is improved, and image noise and filming can be further suppressed.

  According to the present invention, since the sheet member is composed of a material that frictionally charges the developer to the positive charging side or a material that frictionally charges the developer to the reverse charging side, the sheet member functions as a charge eliminating member. Since the residual toner on the agent carrier is adsorbed to the sheet member side, the recovery efficiency is improved, and image noise and filming can be further suppressed.

  According to the present invention, since the residual toner on the developer carrying member is recovered well, the occurrence of image noise and filming in the development system is suppressed, and a good image can be obtained.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a schematic configuration of an image forming apparatus 100 including a developing device 5 and a process cartridge 50 according to the present invention. The image forming apparatus 100 includes a drum-shaped photoreceptor (hereinafter referred to as “photoreceptor drum”) 1 as an image carrier. Around the photosensitive drum 1, a charging roller 3 as a charging unit, a developing device 5, a transfer roller 6 as a transfer unit, and a cleaning unit 4 are arranged. Among these components, the photosensitive drum 1, the charging roller 3, the cleaning unit 4, and the developing device 5 are housed in a casing 7 and configured as a process cartridge 50. The process cartridge 50 is detachable from the image forming apparatus main body 100a. In this embodiment, in order to form yellow, magenta, cyan, and black toner images, the four process cartridges 50 are arranged in a horizontal row to constitute the image forming unit. The components related to yellow, magenta, cyan, and black are identified by being assigned Y, M, C, and K, respectively. For example, yellow, magenta, cyan, and black process cartridges are indicated as process cartridges 50Y, 50M, 50C, and 50K, respectively, and yellow, magenta, cyan, and black developing devices are indicated as developing devices 5Y, 5M, 5C, and 5K, respectively.

  The configuration of each process cartridge and the developing device is basically the same except that the color of the toner to be used is different. For this reason, the description of Y, M, C, and K is omitted except for cases relating to color image formation.

  Between the charging rollers 3Y, 3M, 3C, and 3K provided in the process cartridges 50Y, 50M, 50C, and 50K and the developing devices 5Y, 5M, 5C, and 5K, each color is supported by the optical scanning device 8 serving as a latent image forming unit. The laser beams 11Y, 11M, 11C, and 11K that form the latent images are irradiated.

  Below the transfer rollers 6Y, 6M, 6C, and 6K, an intermediate transfer unit 9, a fixing unit 10, and a paper feeding device 200 are arranged. The intermediate transfer unit 8 includes a belt-like intermediate transfer medium 91 wound around a plurality of roller members. The intermediate transfer medium 91 is configured to be rotated in the clockwise direction in FIG.

  Next, a series of processes for image formation by the image forming apparatus 100 will be described by taking a negative / positive process as an example. The photosensitive drums 1Y, 1M, 1C, and 1K represented by the photosensitive member (OPC) having the organic photoconductive layer shown in FIG. 1 are neutralized by a neutralizing lamp (not shown) or the like, and are charged by the charging rollers 3Y, 3M, 3C, and 3K. Uniformly negatively charged. When the respective photosensitive drums are charged by the respective charging rollers 3, an appropriate size suitable for charging the respective photosensitive drums 1 to a desired potential from a voltage applying means (not shown) to the respective charging rollers. A voltage or a charging voltage obtained by superimposing an AC voltage thereon, that is, a voltage having an AC component is applied.

  Each charged photosensitive drum 1 forms a latent image with each laser beam 11 irradiated from the latent image forming device 8 (the absolute value of the exposed portion potential is lower than the absolute value of the non-exposed portion potential). Is done. Each laser beam 11 is emitted from a semiconductor laser and scans the surface of the photosensitive drum 1 in the direction of the rotation axis of the photosensitive drum 1 by a polygonal polygonal mirror (polygon) that rotates at high speed.

  The latent image formed on each photosensitive drum 1 in this way is developed from toner particles serving as a developer supplied from each developing device 5 to form a toner image. The process of forming such a toner image is performed corresponding to each color of yellow, magenta, cyan, and black.

  The toner image formed on the photosensitive drum 1 corresponding to each color is sequentially transferred (primary transfer) onto the intermediate transfer medium 91 by each transfer roller 6. At this time, it is preferable that a potential having a polarity opposite to that of toner charging is applied to each transfer roller 6 as a transfer bias. The toner particles remaining on the respective photosensitive drums 1 after the transfer are respectively collected by the cleaning means 4 to the toner collecting portion in the cleaning means 4.

  The toner image transferred onto the intermediate transfer medium 91 is fed from the paper feeding device 200 by a secondary transfer roller 92 that is disposed opposite to the intermediate transfer medium 91 in front of the fixing unit 10 and to which a secondary transfer bias is applied. It is transferred (secondary transfer) all at once onto the transfer medium P such as paper. The transferred transfer medium P is fixed by the fixing unit 10 and discharged to the paper discharge tray 101.

  Although the image forming apparatus 100 according to the present embodiment has been described as an intermediate transfer method, the image forming apparatus 100 is a method in which a plurality of toner images sequentially produced by a plurality of developing devices 5 are directly transferred onto a recording medium P sequentially. Also good. The image forming apparatus is not limited to a color image forming apparatus, and may be an image forming apparatus that forms a monochrome image. Further, the image forming apparatus is not limited to a printer or a copying machine, but may be a facsimile alone or a multifunction machine having a plurality of functions such as a printer and a copying machine. In this embodiment, the developing device 5 is integrally incorporated in the process cartridges 50 of the respective colors. However, the developing device 5 may not be a process cartridge but may be detachably attached to the image forming apparatus main body 100a.

  Next, the configuration of the developing device 5 will be described with reference to FIG.

  The developing device 5 is rotatable in a developing case 51 and supplies a toner T to a developing roller 52 serving as a developer carrying member that supplies toner to the photosensitive drum 1 and a surface 52 a of the developing roller 52. In addition, a roller member 53 serving as a rotatable developer collecting member that collects the residual toner T1 from the surface 52a of the developing roller 52, a sheet member 2 that contacts the developing roller 52 in the developing case 51, and an elastic member 54 In addition, a blade 55 serving as a layer thickness regulating member that regulates the layer thickness of the toner T supplied to the photosensitive drum 1 is provided. It has.

  In FIG. 2, the developing case 51 is vertically divided into two by a partition wall 56, and an upper portion is a toner storage chamber 57 and a lower portion is a toner supply chamber 58. The toner storage chamber 57 is provided with a toner stirring member 59 that rotates clockwise in FIG. 2 and stirs the toner T stored in the toner storage chamber 57. The partition wall 56 is formed with an opening 60 that allows the toner storage chamber 57 and the toner supply chamber 58 to communicate with each other. The toner T in the toner storage chamber 57 is supplied from the opening 60 to the toner supply chamber 58 by the rotating operation of the toner stirring member 59.

  The roller member 53 is connected to the bias applying unit 61 and is configured such that a supply bias having a value offset in the same direction as the charging polarity of the toner T with respect to the developing bias is applied from the bias applying unit 61. ing. The roller member 53 is disposed in the toner supply chamber 58 so as to contact the developing roller 52 with a constant force. At this time, if at least one of the roller member 53 and the developing roller 52 is an elastic body, there is no problem in contact with each other. However, if the developing roller 52 is a non-elastic body, the roller member 53 needs to be an elastic body, and the image carrier needs to be in a non-contact position with the belt or the developing roller 52. In this embodiment, the photosensitive drum 1 and the developing roller 52 are in contact with each other, and the roller member 53 is formed of an elastic body and is in contact with the surface of the roller member 52.

  The supply bias to the roller member 53 acts in a direction in which the toner T preliminarily charged at the contact portion with the developing roller 52 is pressed against the surface 52 a of the developing roller 52. When the roller member 53 is driven to rotate clockwise by a driving unit (not shown), the toner T adhered to the surface 53a is applied and supplied to the surface 52a of the developing roller 52.

  A developing bias for forming an electric field between the developing roller 52 and the surface 1 a of the photosensitive drum 1 is applied by a developing bias applying unit 62. When the developing roller 52 is rotated in a clockwise direction in FIG. 2 by a driving unit (not shown), the developing roller 52 conveys the toner T held on the surface 52 a to a position facing the blade 55 and the photosensitive drum 1.

  The blade 55 is disposed downstream of the contact position between the roller member 53 and the developing roller 62 in the developing roller rotation direction. The blade 55 has its free end 55a side abutted against the surface 52a of the developing roller 52 with a pressing force of 10 to 40 N / m, and the toner T that has passed under the pressing is made thin and frictionally charged. Charge is applied to the toner T. Further, a regulation bias application means 63 applies a regulation bias having a value offset in the same direction as the charging polarity of the toner T with respect to the developing bias in order to assist frictional charging.

  In FIG. 2, the photosensitive drum 1 is rotationally driven in a counterclockwise direction by a driving means (not shown). Therefore, the surface 52 a of the developing roller 52 moves in the same direction as the traveling direction of the surface 1 a of the photosensitive drum at a position facing the photosensitive drum 1.

  The thinned toner T is conveyed to a position facing the photosensitive drum by the rotation of the developing roller 52, and the latent image formed by the developing bias applied to the developing roller 52 and the electrostatic latent image on the photosensitive drum. In accordance with the image electric field, it moves to the surface 1a of the photosensitive drum 1 and develops the electrostatic latent image.

  Between the developing roller 52 and the bottom 58a of the toner supply chamber 58, the sheet member 2 and the elastic member 54 are disposed. This portion is a position where residual toner T1 which is not used for development on the photosensitive drum 1 and remains on the surface 52a of the developing roller 52 can be returned to the toner supply chamber 53 again by the rotation of the developing roller 52.

  The elastic member 54 is fixed to the bottom 58 a of the toner supply chamber 58 located on the opposite side of the contact surface 2 c of the sheet member 2 with the developing roller 52, and the one end 2 a side of the sheet member 2 is connected to the surface of the developing roller 52. It has the function of making it contact elastically with respect to 52a. One end 2 a of the sheet member 2 is located inside the developing case 51, the other end 2 b of the sheet member 2 located on the opposite side is located outside the developing case 51, and the elastic member 54 is placed on the bottom 58 a of the toner supply chamber 58. The toner supply chamber 58 is fixed to the developing case 51 so as to close the end 58a so that the toner supply chamber 58 does not fall. The toner T in the toner supply chamber 58 is sealed by the sheet member 2 so as not to leak out of the developing case 51.

  Therefore, when the developing roller 52 rotates, the residual toner T1 remaining on the surface 52a passes through the contact portion A with the sheet member 2 and is guided into the toner supply chamber 58, and rotates in the clockwise direction. The roller member 53 is peeled off and collected from the surface 52a of the developing roller 52. That is, in this embodiment, the roller member 53 functions as a toner supply member that supplies the toner T to the surface 52 a of the developing roller 52 and a developer recovery member that recovers the residual toner T1 from the surface 52 a of the developing roller 52.

  Here, the residual toner T collected by the roller member 53 is more easily collected as the pressing force of the sheet member 2 pressed against the surface 52a of the developing roller 52 by the elastic member 54 is stronger. This is because the adhesive force of the residual toner T1 to the surface 52a is weakened by the pressing force of the sheet member 2.

  FIG. 3 is a diagram illustrating the characteristics of the toner amount after collection on the surface 52a of the developing roller and the collection performance of the roller member 53. In the figure, a thick solid line indicates the characteristic after passing a blank sheet when there is no sheet member 2, a thin solid line indicates a characteristic after solid image formation when there is no sheet member 2, and a broken line indicates a case where the sheet member 2 is present. The characteristics after passing through the blank paper. From FIG. 3, it is preferable that the recovery efficiency of the roller member 53 is higher in the related art because no developing toner history remains on the developing roller 52 and problems such as filming do not occur. However, the closer to the complete recovery, the more it is necessary to raise the charge level of the toner T supplied from the roller member 53 to the developing roller 52 with the blade 55 at a time. This becomes a problem such as contamination (area B1).

  On the contrary, if the collection performance of the roller member 53 is too low, the residual toner T1 that is not developed on the developing roller 52 is gradually accumulated, so that a sufficient toner layer cannot be formed, and image noise occurs (area B2). .

  A region B3 in FIG. 3 shows a region of appropriate collection performance by the roller member 53. However, if the adhesive force of the residual toner T1 is not reduced in advance by the sheet member 2, a large amount of toner is formed on the developing roller 52 after passing the blank paper. When the amount remains, the collection performance is significantly different from the state after the solid passage (thin solid line). Therefore, a density difference occurs between the portion after the blank sheet and the solid portion, and a positive remaining memory is generated.

Therefore, even when a large amount of residual toner T1 after white paper remains, it is effective to mechanically disperse the residual toner T1 with the sheet member 2 in order to obtain sufficient recovery performance. As shown in a), the residual toner T1 scraped off by the sheet member 2 before being collected by the roller member 53 is accumulated between one end 2A of the sheet member and the surface 52a of the developing roller 52, and filming is performed. It becomes a generation factor. Further, as shown in FIG. 9B, when the bending of the elastic member 54 is used to press the sheet member 2 against the developing roller 52, the elastic member 54 is crushed and deformed along the outer peripheral surface 52 a of the developing roller 52. To do. Therefore, the end 2a of the sheet member 2 located in the developing case 51 is also deformed along the outer peripheral surface 52a of the developing roller 52 and passes through the contact portion A, rather than the contact portion A between the developing roller 52 and the sheet member 2. The residual toner T1 is likely to stay at the one end 2a, causing a recovery failure from the developing roller 52.
(First embodiment)
Therefore, in the first embodiment, as shown in FIGS. 2 and 4, the residual toner T1 written by the sheet member 2 can be returned to the toner supply chamber 58 of the developing case 51 without accumulating in the sheet member 2. Further, the one end 2 a of the sheet member 2 located in the developing case 51 (toner supply chamber 58) is located between the sheet member 2 and the surface 52 a of the developing roller 52, rather than the contact portion A of the sheet member 2 with the developing roller 52. The tangent line G is disposed in a direction away from the surface 52 a of the developing roller 52.

With such a configuration, the residual toner T1 that has passed through the sheet member 2 is less likely to stay on the one end 2a, and can be easily returned to the developing case 51 (toner supply chamber 58). For this reason, the residual toner T1 is not gradually accumulated on the surface 52a of the developing roller 52 due to poor collection, a sufficient toner layer can be formed, and image noise and filming can be suppressed. As described above, when the residual toner T1 on the developing roller 52 is collected well, generation of image noise and filming in the developing system is suppressed, and a good image can be obtained.
(Second Embodiment)
In this embodiment, as shown in FIG. 5, one end 2 a of the sheet member 2 is fixed to the elastic member 54 positioned below the sheet member 2, and the direction away from the surface 52 a of the developing roller 52 from the tangent line G. Arranged.

With such a configuration, the one end 2a is stabilized at a position away from the surface 52a of the developing roller 52, and the residual toner T1 that has passed through the sheet member 2 reliably falls into the case. For this reason, the residual toner T1 is not gradually accumulated on the developing roller 52 due to poor collection, a sufficient toner layer can be formed, image noise and filming can be further suppressed, and good An image can be obtained.
(Third embodiment)
In this embodiment, as shown in FIG. 6, the one end 2 a of the sheet member 2 is disposed so as to contact the surface 53 a of the roller member 53. For this reason, when the roller member 53 rotates, the one end 2a of the sheet member 2 is shaken, so that the residual toner T1 that has passed through the sheet member 2 reliably falls into the developing case 51. Therefore, the residual toner T1 is not gradually accumulated on the developing roller 52 due to poor collection, and a sufficient toner layer can be formed, image noise and filming can be further suppressed, and a good image can be obtained. Can be obtained.
(Fourth embodiment).

In this embodiment, as shown in FIG. 7, the other end 2 b of the sheet member 2 is not fixed and is a free end. As described above, when the other end 2b of the sheet member 2 is a free end, the position of the other end 2b is higher than when the other end 2b is fixed to the developing case 51. For this reason, the toner receiving portion is configured upstream of the contact portion A in the rotation direction of the developing roller 52, and the width of the contact portion A with respect to the rotation direction of the developing roller 52 is widened, so that leakage occurs from the other end side. It becomes difficult.
(Fifth embodiment)
In this embodiment, as shown in FIG. 8, the sheet member 2 is formed of a conductive member, and a voltage is applied to the conductive sheet member 2 by a voltage applying unit 64.

  According to such a configuration, the voltage acts strongly on the residual toner T1 on the developing roller 52 from the sheet member 2 particularly in the vicinity of the contact portion A, and the residual toner T1 is adsorbed on the sheet member 2 side. For this reason, the collection efficiency of the residual toner T1 is improved, image noise and filming can be further suppressed, and a good image can be obtained.

  When the voltage applied to the sheet member 2 is the same polarity as that of the residual toner T1, the residual toner T1 cannot be electrically attracted to the sheet member 2. When the voltage is opposite to the residual toner T1, the residual toner T1 is attracted to the surface of the developing roller 52 There is a possibility that toner spillage may occur due to the excessive peeling force from 52a. For this reason, it is preferable to apply the same voltage as the voltage applied to the developing roller 52 as the voltage applied to the sheet member 2.

  The sheet member 2 may be made of a material that frictionally charges the residual toner T1 to the positive charging side. With such a material, the charge amount of the residual toner T1 is reduced. For this reason, the adhesion force of the residual toner T1 to the surface 52a of the developing roller 52 is weakened, and it is easy to be attracted to the sheet member 2 side, thereby improving the collection efficiency and further suppressing the occurrence of image noise and filming. And a good image can be obtained.

  The material of the sheet member 2 may be a material that frictionally charges the residual toner T1 on the surface 52a of the developing roller 52 to the reverse charging side. Even in this configuration, the amount of charge of the residual toner T1 is reduced, so that the adhesive force of the residual toner T1 to the surface 52a of the developing roller 52 is weakened, and the residual toner T1 is easily attracted to the sheet member 2 side. For this reason, collection efficiency is improved, image noise and filming can be further suppressed, and a good image can be obtained.

1 is a schematic configuration diagram illustrating an example configuration of an image forming apparatus in which a process cartridge including a developing device according to the present invention is detachable. FIG. 3 is an enlarged view showing a configuration example of a developing device according to the present invention. FIG. 6 is a characteristic diagram for explaining the relationship between the amount of toner after recovery from the developer carrying member and the recovery efficiency of the developer recovery member. FIG. 2 is an enlarged view showing a configuration of a main part of the developing device according to the first embodiment of the present invention. It is an enlarged view which shows the structure of the principal part of the developing device which concerns on the 2nd Embodiment of this invention. It is an enlarged view showing a configuration of a main part of a developing device according to a third embodiment of the present invention. It is an enlarged view which shows the structure of the principal part of the developing device which concerns on the 4th Embodiment of this invention. It is an enlarged view which shows the structure of the principal part of the developing device which concerns on the 5th Embodiment of this invention. (A) is an enlarged view for explaining a problem of a developing device using a sheet member alone, and (b) is an enlarged view for explaining a problem of a developing device using a sheet member and an elastic member.

Explanation of symbols

1 (Y, M, C, K) Image carrier 1a Surface of image carrier 2 (Y, M, C, K) Sheet member 2a (Y, M, C, K) one end 2b (Y, M, C, K) K) Other end 2c (Y, M, C, K) contact surface 4 (Y, M, C, K) Cleaning means 50 (Y, M, C, K) Process cartridge 51 (Y, M, C, K) Developing case 52 (Y, M, C, K) developer carrier 53 (Y, M, C, K) developer collecting member 54 (Y, M, C, K) elastic member 100 Image forming apparatus 100a Image forming apparatus Body G Tangent T, T1 Developer

Claims (12)

A developer carrying member which is rotatable in the developing case and supplies the developer to the image carrying member; a rotatable developer collecting member for collecting the developer from the developer carrying member; A sheet member that contacts the developer carrier, and an elasticity that elastically contacts the sheet member to the developer carrier on a side of the sheet member opposite to the contact surface with the developer carrier. In a developing device provided with a member,
A direction in which one end of the sheet member positioned in the developing case with respect to the contact portion with the developer carrier is separated from the developer carrier with respect to a tangent line between the sheet member and the developer carrier. The developing device is arranged in   A direction in which one end of the sheet member positioned in the developing case with respect to the contact portion with the developer carrier is separated from the developer carrier with respect to a tangent line between the sheet member and the developer carrier. The developing device according to claim 1, wherein the developing device is fixedly disposed on the developing device.   2. The sheet member according to claim 1, wherein one end of the sheet member located in the developing case is in contact with the developer collecting member rather than a contact portion with the developer carrying member. Development device.   4. The developing device according to claim 1, wherein the other end of the sheet member positioned opposite to the one end of the sheet member is not fixed. 5.   The developing device according to claim 1, wherein the sheet member is conductive.   6. The developing device according to claim 1, wherein a voltage is applied to the sheet member.   7. The developing device according to claim 1, wherein the same voltage as that applied to the developer carrying member is applied to the sheet member.   The developing device according to claim 1, wherein the sheet member is made of a material that frictionally charges the developer to a positively charged side.   The developing device according to claim 1, wherein the sheet member is made of a material that frictionally charges the developer to a reverse charging side.   An image forming apparatus comprising the developing device according to claim 1. A process cartridge that includes at least an image carrier and a developing device and is detachable from an image forming apparatus main body;
A process cartridge comprising the developing device according to claim 1 as the developing device.   An image forming apparatus comprising the process cartridge according to claim 11.

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