JP4640308B2 - Development device - Google Patents

Description

  The present invention relates to a developing device, and more particularly to a doctor blade that regulates the thickness of a developing layer of a developer adhered to an outer peripheral surface of a developing sleeve.

  2. Description of the Related Art Conventionally, in an image recording apparatus using an electrophotographic method such as a facsimile, a developer is stored in a developing device, and the developer is adhered in a layered manner to the outer peripheral surface of a developing sleeve of the developing device. The developer is transferred to the photosensitive drum of the drum unit (see, for example, Patent Document 1).

For example, as shown in FIG. 7, in a two-component developing device in which the developer 22 is composed of toner and carrier, the developing layer thickness of the developer 22 formed on the outer peripheral surface of the developing sleeve 51 is set to a predetermined thickness. In order to regulate, a doctor blade (regulating blade) 52 is provided. The doctor blade 52 is formed of a plate-like member, and a corner portion 53 having a small R is formed at the tip of the plate-like member and upstream of the developer in the moving direction on the developing sleeve. ing. The doctor blade 52 is provided so that the corner portion 53 is brought close to the outer peripheral surface of the developing sleeve 51 so as to secure a separation distance of about 0.3 mm. When the adhered developer 22 moves on the outer peripheral surface of the developing sleeve 51, an excess portion of the developer 22 is removed by coming into contact with the corner portion 53.
JP 2002-214904 A

  By the way, the conventional doctor blade 52 is formed of a plate-like member. When the doctor blade 52 is thin, a part of the developer 22 removed at the corner 53 of the doctor blade 52 is shown in FIG. Like 22a, it may wrap around the back side of the doctor blade 52 and accumulate. When the doctor blade 52 is vibrated, the accumulated developer 22a is peeled off, and the developer 22a adheres to the outer surface of the developing sleeve 51, thereby degrading the image quality.

  Therefore, in order to prevent the removed developer 22 from going around and depositing on the back side of the doctor blade 52, a portion along the circumferential direction of the developing sleeve 51 is increased by increasing the plate thickness as shown in FIG. A longer doctor blade 52 has been developed. However, when the thickness of the entire doctor blade 52 is increased, there is a problem that the dimensional accuracy of the cut surface of the end portion is lowered when processed by a processing apparatus such as a punching press machine. There arises a problem that the accuracy of the developing layer thickness of the developer 22 to be formed is lowered. Further, when the plate thickness of the doctor blade 52 is increased as a whole, the thickness of the portion 54 irrelevant to the regulation of the thickness of the developing layer also increases, and there is a problem that the cost of the doctor blade 52 is increased due to an increase in the waste portion. is there.

  Therefore, as shown in FIG. 9, by making the cross-sectional shape of the doctor blade 52 substantially L-shaped, the portion along the circumferential direction of the developing sleeve 51 is lengthened, and the removed developer 22 is removed from the doctor blade 52. There has also been developed a doctor blade 52 that prevents an increase in cost by preventing an increase in useless portions that are irrelevant to the regulation of the developing layer thickness of the developer 22 while preventing the deposition from going around to the back side. However, when the doctor blade 52 having a substantially L-shaped cross section is formed by a processing machine such as a bending machine, the rigidity of the doctor blade 52 is secured if the plate thickness is increased, but the bending portion R that becomes the corner portion 53 has a large R. Thus, there arises a problem that the accuracy of the developing layer thickness of the developer 22 is lowered.

  On the other hand, if the plate thickness is reduced, the corner portion 53 of the bent portion 53 can be formed with a small R, but the rigidity of the doctor blade 52 is not ensured, so that the separation distance between the doctor blade 52 and the outer surface of the developing sleeve 51 is maintained. The problem of being unable to do so arises. In addition, when the doctor blade 52 having a substantially L-shaped cross section is formed by a drawing apparatus, the thickness can be increased to increase the rigidity, and the doctor blade 52 can be formed with a small R at the corner 53, There is a problem that the cost of the drawing process is high and the cost of the doctor blade 52 is increased.

  The present invention has been made in view of the above problems, and the doctor blade has high rigidity, can reduce the corner R, can increase the accuracy of the developing layer thickness of the developer, and can be removed. An object of the present invention is to provide a developing device including a doctor blade that can prevent the developer from flowing around and depositing on the back side of the doctor blade.

  The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described.

That is, in the invention according to claim 1, in a developing device comprising a developing sleeve in which a developer composed of toner and a carrier moves on an outer surface, and a doctor blade disposed to face the developing sleeve.
The doctor blade is
A main body of a blade having a corner portion formed by bending a thin metal plate into a substantially L-shaped cross section to form a support portion and a developer wraparound prevention portion, and having a small R on the dominant angle side of the bent portion. When,
A reinforcing member attached to the minor angle side of the blade main body and reinforcing the blade main body,
The doctor blade is disposed on the upstream side in the moving direction of the developing sleeve of the developing agent, and is arranged to close in a state where the corner portion has secured the distance against the outer surface of the developing sleeve In addition, the developing device is characterized in that the wraparound prevention portion is disposed so as to extend downstream in the moving direction of the developer along the tangential direction of the developing sleeve at the corner portion.

  In invention of Claim 2, in the invention of Claim 1, R of the corner | angular part of the said metal plate shall be 0.1 mm or more and 0.2 mm or less.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the reinforcing member includes a plurality of reinforcing members arranged at predetermined intervals in the central axis direction of the developing sleeve. It was decided to be a rib.

In a fourth aspect of the present invention, in the developing device, comprising: a developing sleeve in which a developer composed of toner and a carrier moves on the outer surface; and a doctor blade disposed to face the developing sleeve.
The doctor blade is
A blade main body in which a thin metal plate is bent into a substantially L-shaped cross section to form a support portion and a developer wraparound prevention portion;
A reinforcing member attached to the dominant angle side of the supporting portion of the blade main body,
The reinforcing member has a corner portion formed with a small R at at least one end portion, the corner portion is located upstream of the blade main body in the moving direction of the developer on the developing sleeve, and The end is attached so as to be continuous with the wraparound prevention part,
The doctor blade is disposed on the upstream side in the moving direction of the developing sleeve of the developing agent, and is arranged to close in a state where the corner portion has secured the distance against the outer surface of the developing sleeve In addition, the developing device is characterized in that the wraparound prevention portion is disposed so as to extend downstream in the moving direction of the developer along the tangential direction of the developing sleeve at the corner portion.

  In the invention according to claim 5, in the invention according to claim 4, R of the corner portion formed in the reinforcing member is 0.1 mm or more and 0.2 mm or less.

  According to a sixth aspect of the present invention, in the invention according to any one of the first to fifth aspects, a sheet-like member is attached to the wraparound prevention portion, and the leading end of the sheet-like member is a wraparound prevention portion. It protrudes from the end of the developer to the downstream side in the developer moving direction.

  According to a seventh aspect of the present invention, in the sixth aspect of the invention, a wall body having a shape along the outer periphery of the developing sleeve is formed inside the casing in which the developing sleeve is accommodated, and is attached to the doctor blade. The obtained sheet-like member is in contact with the wall body in an elastically deformed state.

  As effects of the present invention, the following effects can be obtained.

  According to the first aspect of the present invention, since the blade main body of the doctor blade can form the dominant angle side of the bent portion as a corner portion having a small R by reducing the thickness of the metal plate, the developer The accuracy of the developing layer thickness can be increased. In addition, since the reinforcing member is provided on the minor angle side of the blade main body, the rigidity of the doctor blade can be increased, and the separation distance between the doctor blade and the outer peripheral surface of the developing sleeve can be maintained. Further, since the blade main body is formed with a wraparound prevention portion by being bent into a substantially L-shaped cross section, it is possible to prevent the removed developer from wrapping around the back side of the doctor blade.

  According to invention of Claim 2, the precision of the developing layer thickness of a developer can be made higher by forming R of a corner part into 0.1-0.2 mm.

  According to a third aspect of the present invention, a plurality of reinforcing members that are attached to the under-angle side of the blade main body and reinforce the blade main body are arranged at predetermined intervals in the central axis direction of the developing sleeve. The ribs of the book can increase the rigidity of the doctor blade, maintain the distance between the doctor blade and the developing sleeve surface, and reduce the weight of the doctor blade.

  According to the invention described in claim 4, since the wraparound prevention portion and the corner portion are formed in separate members, the reinforcing member formed with the corner portion is a member having a thin plate thickness and rigidity. Can be used. For this reason, even if the reinforcing member is processed by a processing apparatus such as a punching press, the corner R can be formed small, and the accuracy of the developer layer thickness of the developer can be increased. In addition, since the reinforcing member is provided on the dominant angle side of the supporting portion of the blade main body, the rigidity of the doctor blade can be increased, and the separation distance between the doctor blade and the outer peripheral surface of the developing sleeve can be maintained. it can. Further, since the wraparound prevention part is formed on the blade main body, it is possible to prevent the removed developer from wrapping around and depositing on the back side of the doctor blade.

  According to the fifth aspect of the present invention, by forming the corner R to 0.1 to 0.2 mm, the accuracy of the developing layer thickness of the developer can be further increased.

  According to the sixth aspect of the present invention, since the sheet-like member is attached to the wraparound prevention portion, the removed developer is prevented from wrapping around the back side of the doctor blade beyond the wraparound prevention portion. can do.

  According to the seventh aspect of the present invention, the sheet-like member is attached to the wraparound prevention portion, and the sheet-like member is in contact with the wall body inside the casing in an elastically deformed state. It is possible to reliably prevent the agent from flowing around and depositing on the back side of the doctor blade.

  Next, embodiments of the invention will be described with reference to the drawings.

  A developing device 10 according to Embodiment 1 of the present invention will be described with reference to FIGS.

  First, the overall configuration of the image forming apparatus 31 including the developing device 10 of the present embodiment will be described. As shown in FIG. 1, the image forming apparatus 31 is disposed above the paper feed cassette 32, and from the paper feed cassette 32. The recording paper on which the image information is visualized is transferred onto the fed recording paper, and the recording paper on which the toner image is fixed passes through a main transport path 34 to a paper discharge tray 33 provided on the upper part of the image forming apparatus 31. It is configured to be discharged. Further, a reversing path 35 for duplex printing is formed outside the main transport path 34, and the reversing path 35 is configured to branch and merge with the main transport path 34. A photosensitive drum unit 36, an exposure device 37, a developing device 10, a fixing device unit 38, and the like are arranged along the main transport path 34.

  As shown in FIG. 1, the photosensitive drum unit 36 includes a photosensitive drum 39, a charger 40 that charges the surface of the photosensitive drum 39, a cleaning device 41 that cleans the surface of the photosensitive drum 39, and the like. Yes. An electrostatic latent image is formed on the surface of the photosensitive drum 39 of the photosensitive drum unit 36.

  As shown in FIG. 1, the exposure device 37 is disposed obliquely below the photosensitive drum 39. In this embodiment, a fixed scanning type using an LED head is provided as an exposure device. The LED head performs image exposure based on the digitized image information on the outer peripheral surface of the photosensitive drum 39 charged by the charger 40, whereby an electrostatic latent image is formed on the outer peripheral surface of the photosensitive drum 39. The

  As shown in FIG. 1, the developing device 10 includes a casing 11, a stirring chamber 12, a developing sleeve 14, a doctor blade 15, and a transport paddle 13. In the developing device 10, the two-component developer 22 is adsorbed and supported on the outer peripheral surface of the developing sleeve 14 by the magnetic force of the developing sleeve 14 to form a brush-like developing layer. The developer 22 is supplied to the developing sleeve 14 by the transport paddle 13. The developing sleeve 14 is rotated clockwise in FIG. 1, and the developing layer of the brush-like developer 22 carried on the outer peripheral surface of the developing sleeve 14 is moved between the developing sleeve 14 and the photosensitive drum 39. Then, the toner in the developer 22 adhering to the outer peripheral surface of the developing sleeve 14 is electrostatically latent on the photosensitive drum 39 by an electric field formed between the developing sleeve 14 and the electrostatic latent image on the photosensitive drum 39. The toner is developed by moving in the direction of the image.

  As shown in FIG. 1, the fixing unit 38 includes a heat roller 42, a press roller 43 disposed with the main conveyance path 34 interposed therebetween so as to be in pressure contact with the outer peripheral surface of the heat roller 42. It is configured as a unit body. In the fixing unit 38, the recording paper on which toner is transferred is sent to the nip portion between the heat roller 42 and the press roller 43, and is heated and pressurized to fix the toner image on the recording paper.

  Next, the doctor blade 15 will be described. As shown in FIG. 2, the doctor blade 15 regulates the developing layer thickness of the developer 22 formed on the outer peripheral surface of the developing sleeve 14 to a predetermined thickness, and the blade main body 16 and the reinforcing member 20 are connected to each other. Have. In the following description, at the position facing the doctor blade 15, the starting end side of the arrow indicating the moving direction of the developer on the developing sleeve is described as upstream, and the end side is described as downstream.

  As shown in FIG. 3, the blade main body 16 is formed by bending a thin metal plate into a substantially L-shaped cross section, and is formed with a support portion 17, a wraparound prevention portion 18, and a corner portion 19. Yes. The support portion 17 is a portion for fixing the doctor blade 15 to the developing device 10. The corner portion 19 is a portion for removing excess developer 22 out of the developer 22 attached to the outer peripheral surface of the developing sleeve 14. R on the dominant angle side of the corner portion 19 is formed to be small enough to remove the excess developer 22 when the excess developer 22 out of the developer 22 abuts. Is preferably about 0.1 to 0.2 mm. The wraparound prevention part 18 is a part that prevents the developer 22 removed at the corner part 19 from wrapping around the back side (downstream side) of the doctor blade 15.

  As the metal material of the blade main body 16, brass or the like can be used, and the thickness of the metal plate is a bending outer radius of the bent portion that becomes the corner portion 19 by performing a bending process using a processing machine such as a bending machine. It is preferable to set it as the plate | board thickness which can form in 0.1-0.2 mm. Therefore, it is preferable to use a thin metal plate having a thickness of about 0.1 to 0.2 mm.

  As a means for forming the blade main body 16, for example, first, a metal plate is formed so as to have a substantially band shape by a processing device such as a punching press machine. The length in the longitudinal direction is substantially equal to the length of the developing sleeve 14. Then, the substantially strip-shaped metal plate is bent into a substantially L-shaped cross section by a processing machine such as a bending machine along the longitudinal direction, and the long side of the bent portion is used as the support portion 17 and the short side is prevented from wrapping around. 18 In addition, the dominant angle side of the bent portion is a corner portion 19. The bending outer radius of the corner portion 19 is preferably formed in a range of 0.1 to 0.2 mm, and the bending outer radius is preferably formed to have substantially the same dimension over the entire length of the corner portion 19.

  A reinforcing member 20 is provided on the inferior angle side of the blade main body 16. The reinforcing member 20 is a member that reinforces the support portion 17 of the blade main body 16 formed of a thin metal plate and ensures the rigidity of the doctor blade 15. The reinforcing member 20 is formed of a metal plate and is fixed to the support portion 17 of the blade main body 16 with bolts and nuts. You may fix the reinforcement member 20 and the support part 17 using fixing means, such as welding. The reinforcing member 20 is not limited to a metal plate, and for example, a reinforcing member 20 formed of a synthetic resin material may be used. When the reinforcing member 20 is a synthetic resin material, the reinforcing member 20 may be fixed to the blade main body 16 using fixing means such as adhesion.

  The doctor blade 15 composed of the blade main body 16 and the reinforcing member 20 is, as shown in FIGS. 2 and 3, fixed means such as a screw on the upstream side in the moving direction of the developer on the developing sleeve 14. Is attached to the attachment portion 21 of the developing device 10, and the wraparound prevention portion 18 is disposed so as to extend downstream in the moving direction of the developer along the tangential direction of the developing sleeve 14 at the corner portion 19. Has been. Further, the corner portion 19 is disposed so as to be close to the outer surface of the developing sleeve 14, and the corner portion 19 has a separation distance of about 0.3 mm with respect to the outer peripheral surface of the developing sleeve 14. It is provided to become. When the developer 22 attached to the outer peripheral surface of the developing sleeve 14 moves, the excess developer 22 out of the developer 22 attached to the outer peripheral surface is removed by coming into contact with the corner portion 19.

  According to the developing device 10 according to the first embodiment described above, the blade main body 16 of the doctor blade 15 has the corner portion 19 formed at the bent portion by reducing the thickness of the metal plate. Since R of the part 19 can be formed as small as 0.1 to 0.2 mm, the accuracy of the developing layer thickness of the developer can be increased.

  Further, since the reinforcing member 20 is provided on the inferior angle side of the blade main body 16, the rigidity of the doctor blade 15 can be increased, and the separation distance between the doctor blade 15 and the outer peripheral surface of the developing sleeve 14 is maintained. can do.

  Further, since the blade main body 16 is formed with a wraparound prevention part 18 by being bent into a substantially L-shaped cross section, it is possible to prevent the removed developer 22 from wrapping around the doctor blade 15 and accumulating. Can do.

  Next, the developing device 10 according to Embodiment 2 of the present invention will be described. The second embodiment is greatly different from the developing device 10 according to the first embodiment in that the reinforcing member 20 of the doctor blade 15 is provided on the dominant angle side of the blade main body 16. The same parts as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 4, the doctor blade 15 of the developing device 10 according to the second embodiment includes a blade main body 16 and a reinforcing member 20.

  The blade main body 16 is formed by bending a thin metal plate, and a support portion 17 and a wraparound prevention portion 18 are formed. In the case of the doctor blade 15 described in the first embodiment, the corner 19 is formed in the blade main body 16, but the corner 19 is not formed in the blade main body 16 of the doctor blade 15 in this embodiment. In Example 1, the thickness of the metal plate is such that the outer radius of the bent portion that becomes the corner portion 19 can be formed to 0.1 to 0.2 mm. Since the portion 19 is not formed, the plate thickness may be the same as or thicker than that of the first embodiment. The planar shape of the metal plate before being bent is substantially a band, and the length in the longitudinal direction is substantially the same as the length of the developing sleeve 14. Then, the metal plate is bent along a longitudinal direction by a processing device such as a bending machine into a substantially L-shaped cross section, and the long side of the bent portion is used as a support portion 17 and the short side is used as a wraparound prevention portion 18.

  A reinforcing member 20 is provided on the dominant angle side of the support portion 17 of the blade main body 16. The reinforcing member 20 is a member that reinforces the support portion 17 of the blade main body 16 formed of a thin metal plate to ensure the rigidity of the doctor blade 15 and is provided with a corner portion 19 at the end. The R of the corner 19 is formed to be small enough to remove the excess developer 22 when the excess developer 22 out of the developer 22 abuts, and the R of the corner 19 is 0.1. It is preferable that the thickness is about 0.2 mm. Moreover, it is preferable to form R of the corner | angular part 19 in substantially the same dimension over the full length.

  It is advantageous in terms of cost to use a processing device such as a punching press machine for processing the reinforcing member 20, but when the punching is performed as the plate thickness of the reinforcing member 20 increases, the corner 19 Since the dimensional accuracy of R is lowered, it is preferable that the thickness of the reinforcing member 20 is a relatively thin plate thickness that can ensure the dimensional accuracy even if processing is performed using a processing apparatus such as a punching press. . In the reinforcing member 20 formed as described above, the corner portion 19 is located upstream of the blade main body in the moving direction of the developer on the developing sleeve 14 and the end portion on which the corner portion 19 is formed. It is attached so that the part is flush with the wraparound prevention part 18 and is continuous. The reinforcing member 20 is fixed to the support portion 17 of the blade main body 16 with bolts and nuts. You may fix the reinforcement member 20 and the support part 17 using fixing means, such as welding.

  The doctor blade 15 comprising the blade main body 16 and the reinforcing member 20 is developed by a fixing means such as a screw on the upstream side in the moving direction of the developer on the developing sleeve 14 as in the first embodiment. The wraparound prevention portion 18 is attached to the attachment portion 21 of the apparatus 10 so as to extend downstream in the developer moving direction along the tangential direction of the developing sleeve 14 at the corner portion 19. Yes. Further, the corner portion 19 is disposed so as to be close to the outer surface of the developing sleeve 14, and the corner portion 19 has a separation distance of about 0.3 mm with respect to the outer peripheral surface of the developing sleeve 14. It is provided to become. When the developing sleeve 14 having the developer 22 attached to the outer peripheral surface rotates, excess developer 22 out of the developer 22 attached to the outer peripheral surface is removed by coming into contact with the corner portion 19.

  According to the developing device 10 according to the second embodiment described above, the wraparound prevention portion 18 and the corner portion 19 are formed of different members. Therefore, the reinforcing member 20 on which the corner portion 19 is formed includes a plate. A member having a small thickness and rigidity can be used. For this reason, even if the reinforcing member 20 is processed by a processing apparatus such as a punching press machine, the corner 19 can be formed with a small R, and the accuracy of the developing layer thickness of the developer 22 can be increased.

  Further, since the reinforcing member 20 is provided on the dominant angle side of the blade main body 16, the rigidity of the doctor blade 15 can be increased, and the separation distance between the doctor blade 15 and the outer peripheral surface of the developing sleeve 14 is maintained. can do.

  Further, since the blade main body 16 is formed with a wraparound prevention part 18 by being bent into a substantially L-shaped cross section, it is possible to prevent the removed developer 22 from wrapping around the doctor blade 15 and accumulating. Can do.

  Next, the developing device 10 according to Embodiment 3 of the present invention will be described. The third embodiment is greatly different from the developing device 10 according to the second embodiment in that the doctor blade 15 is provided with a sheet-like member 23. The same parts as those in the second embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  As illustrated in FIG. 5, a sheet-like member 23 is provided in the wraparound prevention unit 18 of the doctor blade 15 of the developing device 10 according to the third embodiment. The sheet-like member 23 is for preventing the removed developer 22 from going around the back side of the doctor blade 15 beyond the roundabout prevention unit 18. The sheet-like member 23 is formed of a sheet-like synthetic resin material having elasticity, and the length in the longitudinal direction is substantially the same as the length in the longitudinal direction of the wraparound prevention portion 18. One end side of the sheet-like member 23 is stuck along the dominant side of the support portion 17 of the blade main body 16 and the wraparound prevention portion 18, and the other end side is developed more than the end portion of the wraparound prevention portion 18. The agent 22 protrudes downstream in the moving direction. A wall 11a having a shape along the outer periphery of the developing sleeve 14 is formed inside the casing 11 in which the developing sleeve 14 is accommodated, and the sheet-like member 23 attached to the doctor blade 15 is elastically deformed. In contact with the wall 11a. By bringing the sheet-like member 23 into contact with the wall 11a in an elastically deformed state, the space behind the doctor blade 15 is shielded from the space where the developing sleeve 14 is provided.

  According to the developing device 10 according to the third embodiment described above, the sheet-like member 23 is attached to the wraparound prevention unit 18, and the sheet-like member 23 abuts against the wall 11a inside the casing 11 in an elastically deformed state. Since the space on the back side of the doctor blade 15 is shielded from the space in which the developing sleeve 14 is provided, the removed developer 22 is surely prevented from flowing around and depositing on the back side of the doctor blade 15. be able to.

  Next, a developing device 10 according to Embodiment 4 of the present invention will be described. The fourth embodiment is greatly different from the developing device 10 according to another embodiment in that the reinforcing member 20 has a rib shape. The same parts as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 6, the doctor blade 15 in the fourth embodiment is provided with a reinforcing member 20 on the inferior angle side of the blade main body 16. The reinforcing member 20 is a plurality of ribs formed of a thin metal plate or the like. The ribs as the reinforcing member 20 are arranged at a predetermined interval in the central axis direction of the developing sleeve 14 and are provided so as to connect the support portion 17 of the blade main body 16 and the wraparound prevention portion 18. The rigidity of the member 20 is improved. The rib-shaped reinforcing member 20 is formed of a metal material or a synthetic resin material. When the reinforcing member 20 is formed of a thin metal plate, the rib-shaped reinforcing member 20 is attached to the blade main body 16 by welding means or the like. When it is formed of a material, it is attached to the blade main body 16 using an adhesive means or the like.

  According to the developing device 10 according to the fourth embodiment described above, the reinforcing member 20 that is attached to the inferior angle side of the blade main body 16 and reinforces the blade main body 16 has a predetermined direction in the central axis direction of the developing sleeve 14. By being a plurality of ribs arranged at intervals, the rigidity of the doctor blade 15 can be increased, and the separation distance between the doctor blade 15 and the outer surface of the developing sleeve 14 can be maintained, The doctor blade can be reduced in weight.

  The technical scope of the present invention described above is not limited to the above embodiment, and is not limited to the shape of the above embodiment. The technical scope of the present invention broadly covers the entire scope of technical ideas that the present invention truly intends, as will be apparent from the matters described in the present specification and drawings.

FIG. 2 is a cross-sectional view illustrating an overall configuration of an image forming apparatus 31 including the developing device 10 according to the first exemplary embodiment. FIG. 3 is a cross-sectional view of the vicinity of the developing sleeve 14 of the developing device 10. FIG. 3 is an enlarged cross-sectional view of a developing sleeve 14 and a doctor blade 15. FIG. 4 is an enlarged cross-sectional view of a developing sleeve 14 and a doctor blade 15 of a developing device 10 according to a second embodiment. FIG. 9 is an enlarged cross-sectional view of a developing sleeve 14 and a doctor blade 15 of a developing device 10 according to a third embodiment. 9 is an enlarged cross-sectional view of a developing sleeve 14 and a doctor blade 15 of a developing device 10 according to Embodiment 4. FIG. FIG. 3 is an enlarged cross-sectional view of a developing sleeve 51 and a doctor blade 52 of a conventional developing device 10. FIG. 3 is an enlarged cross-sectional view of a developing sleeve 51 and a doctor blade 52 of a conventional developing device 10. FIG. 3 is an enlarged cross-sectional view of a developing sleeve 51 and a doctor blade 52 of a conventional developing device 10.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Developing apparatus 11 Casing 11a Wall body 12 Stirring chamber 13 Conveying paddle 14 Developing sleeve 15 Doctor blade 16 Blade main body 17 Supporting part 18 Rounding prevention part 19 Corner | angular part 20 Reinforcement member 21 Attachment part 22 Developer 23 Sheet-like member 31 Image forming apparatus 32 Paper feeding cassette 33 Paper discharge tray 34 Main transport path 35 Reverse path 36 Photosensitive drum unit 37 Exposure unit 38 Fixing unit 39 Photosensitive drum 40 Charger 41 Cleaning device 42 Heat roller 43 Press roller 51 Development sleeve 52 Doctor blade 53 Corner

Claims (7)

In a developing device comprising a developing sleeve in which a developer composed of toner and a carrier moves on an outer surface, and a doctor blade disposed to face the developing sleeve,
The doctor blade is
A main body of a blade having a corner portion formed by bending a thin metal plate into a substantially L-shaped cross section to form a support portion and a developer wraparound prevention portion, and having a small R on the dominant angle side of the bent portion. When,
A reinforcing member attached to the minor angle side of the blade main body and reinforcing the blade main body,
The doctor blade is disposed on the upstream side in the moving direction of the developing sleeve of the developing agent, and is arranged to close in a state where the corner portion has secured the distance against the outer surface of the developing sleeve In addition, the developing device is characterized in that the wraparound prevention portion is disposed so as to extend downstream in the moving direction of the developer along a tangential direction of the developing sleeve at the corner portion.   2. The developing device according to claim 1, wherein R of a corner portion of the metal plate is 0.1 mm or more and 0.2 mm or less.   The developing device according to claim 1, wherein the reinforcing member is a plurality of ribs arranged at a predetermined interval in a central axis direction of the developing sleeve. In a developing device comprising a developing sleeve in which a developer composed of toner and a carrier moves on an outer surface, and a doctor blade disposed to face the developing sleeve,
The doctor blade is
A blade main body in which a thin metal plate is bent into a substantially L-shaped cross section to form a support portion and a developer wraparound prevention portion;
A reinforcing member attached to the dominant angle side of the supporting portion of the blade main body,
The reinforcing member has a corner portion formed with a small R at at least one end portion, the corner portion is located upstream of the blade main body in the moving direction of the developer on the developing sleeve, and The end is attached so as to be continuous with the wraparound prevention part,
The doctor blade is disposed on the upstream side in the moving direction of the developing sleeve of the developing agent, and is arranged to close in a state where the corner portion has secured the distance against the outer surface of the developing sleeve In addition, the developing device is characterized in that the wraparound prevention portion is disposed so as to extend downstream in the moving direction of the developer along a tangential direction of the developing sleeve at the corner portion.   The developing device according to claim 4, wherein R of a corner portion formed on the reinforcing member is 0.1 mm or more and 0.2 mm or less.   2. A sheet-like member is attached to the wraparound prevention portion, and a leading end portion of the sheet-like member protrudes downstream in the developer moving direction from an end portion of the wraparound prevention portion. 6. The developing device according to any one of items 1 to 5.   A wall body having a shape along the outer periphery of the developing sleeve is formed inside the casing in which the developing sleeve is accommodated, and the sheet-like member attached to the doctor blade comes into contact with the wall body in an elastically deformed state. The developing device according to claim 6, wherein:

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