JP6213237B2 - Development device - Google Patents

Description

  The present invention relates to a developing device including a seal member disposed between both ends of a developing roller and a frame.

  A developing device used in an image forming apparatus such as a laser printer includes a developing roller, a frame for containing a developer, and a seal member disposed between both ends of the developing roller and the frame. In the developing device of Patent Document 1 (see FIG. 8), the outer end of the seal member extends beyond the end of the developing roller (roller portion) in the rotation axis direction of the developing roller.

JP 2001-154480 A

  By the way, in the configuration in which the end of the seal member extends to the outside of the end of the developing roller, the developing roller is pressed against the seal member, so that a relatively large pressing force is applied to the seal member from the end of the developing roller. The member is crushed. As a result, a force to move outward in the rotational axis direction acts on the seal member. Therefore, when the developing roller rotates in this state, the seal member moves outward in the rotational axis direction to create a gap between the seal member and the frame. The developer may leak from the gap.

  The present invention has been made in view of the above background, and provides a developing device capable of suppressing developer leakage in a configuration in which the end of the seal member extends to the outside of the end of the developing roller. With the goal.

In order to achieve the above-described object, the developing device of the present invention includes a developing roller having a roller body configured to carry a developer, a frame that rotatably supports the developing roller, and both ends of the roller body. And an elastically deformable seal member disposed between the portion and the frame.
In the rotation axis direction of the developing roller, the outer end of the seal member is positioned outside the end of the roller body in the rotation axis direction of the seal member.
The frame includes an installation surface on which the seal member is installed, and an inner contact surface that is located on the inner side of the installation surface in the rotation axis direction and contacts an inner end of the seal member.
The installation surface includes a first surface and a second surface disposed on the outer side in the rotation axis direction than the first surface.
The second surface is provided such that an end of the roller body in the rotation axis direction is located within a width of the second surface in the rotation axis direction.
At least a part of the second surface is disposed on the inner side of the first surface in the radial direction of the developing roller.

  According to such a configuration, the second surface on the outer side in the rotational axis direction is disposed radially inward from the first inner surface, so that the seal member can be inclined and disposed. Since the inner end can be pressed against the inner contact surface in a crushed state, the adhesion between the seal member and the inner contact surface can be improved. In addition, even if the seal member is slightly displaced, the crushed portion returns to the original shape, thereby ensuring the adhesion between the seal member and the inner contact surface. Thereby, developer leakage can be suppressed.

  In the developing device described above, the frame may be configured to have an outer contact surface that is positioned outside the installation surface in the rotation axis direction and contacts an outer end of the seal member.

  According to this, since the seal member is sandwiched between the inner contact surface and the outer contact surface, it is possible to suppress the positional deviation of the seal member and to further suppress the developer leakage. .

  In the developing device described above, the installation surface is an inclined surface that approaches the radially inner side from the inner end of the first surface toward the outer end of the second surface in the rotation axis direction. can do.

  According to this, since the force inward in the rotation axis direction acts on the seal member due to the inclination of the installation surface, particularly on the portion sandwiched between the roller body and the installation surface of the seal member, the seal member and the inner contact Adhesion with the surface can be improved. Thereby, toner leakage can be further suppressed.

  In the developing device described above, the first surface is a surface along the rotation axis direction, and the second surface is directed outward from an outer end of the first surface in the rotation axis direction. It can be set as the structure which is an inclined surface which approaches the said radial inside.

  According to this, the seal member is substantially uniform between the first surface along the rotation axis direction and the roller body while applying a force directed inward in the rotation axis direction due to the inclination of the second surface to the seal member. A pressing force can be applied. Thereby, since the adhesiveness between the seal member and the frame or the developing roller can be improved, the developer leakage can be further suppressed.

  In the developing device described above, the installation surface may have a step between the first surface and the second surface.

  In the developing device described above, the seal member may be bonded to the second surface and not bonded to the first surface.

  According to this, since the seal member is not bonded to the first surface, the portion facing the first surface can be easily deformed. It can be pressed against the surface, and the adhesion between the seal member and the inner contact surface can be further enhanced. Further, since the seal member is bonded to the second surface, it is possible to suppress the displacement of the seal member. As a result, developer leakage can be further suppressed.

  In the developing device described above, the second surface is provided between an upstream portion on the upstream side in the rotation direction of the developing roller, a downstream portion on the downstream side in the rotation direction, and between the upstream portion and the downstream portion, It can be set as the structure which has a recessed part dented in the said radial direction outer side rather than an upstream part and the said downstream part.

  According to this, since a part of the seal member enters the recess, the length of the portion that receives a large pressing force from the end of the developing roller can be shortened, so that it tends to move outward in the rotational axis direction acting on the seal member. Can weaken power. Thereby, since the position shift of the seal member can be suppressed, developer leakage can be further suppressed.

  In the developing device described above, the seal member includes a first portion that faces the first surface and a second portion that faces the second surface, and in the rotation direction of the developing roller, The length of the second part may be shorter than the length of the first part.

  According to this, since the length of contact between the second portion and the end of the developing roller can be shortened, it is possible to weaken the force acting on the seal member to move outward in the rotation axis direction. Thereby, since the position shift of the seal member can be suppressed, developer leakage can be further suppressed.

  In the developing device described above, the seal member may have a slit extending in a rotation direction of the developing roller on a surface that contacts the roller body.

  According to this, even when the portion outside the slit of the seal member tries to move outward when the developing roller rotates, the slit opens slightly, so that the portion inside the slit of the seal member moves outward. It becomes difficult to apply force to try. Thereby, since the adhesiveness of a sealing member and a flame | frame can be ensured, a developer leak can be suppressed more.

  In the developing device described above, the slit may be arranged at the same position as the boundary between the first surface and the second surface or inside the boundary in the rotation axis direction.

  According to this, since the position shift of the portion between the first surface and the roller body of the seal member can be suppressed, the adhesion between the portion and the frame or the roller body can be improved. Leakage can be further suppressed.

  In the developing device described above, the seal member includes a first member supported on the installation surface, and a second member disposed between the first member and the developing roller. The member can be configured to be harder than the second member and disposed between the inner contact surface and the outer contact surface.

  According to this, since the position shift of the seal member can be suppressed, developer leakage can be further suppressed.

  In the developing device described above, the inner contact surface is a flat surface along the radial direction, and the inner end of the seal member is viewed from the radially outer side in a state before contacting the inner contact surface. It can be set as the structure which has a shape which approaches the said rotating shaft direction inner side as it goes inside.

  According to this, since it becomes possible to press the inner end of the seal member against the inner contact surface in a more compressed state, the adhesion between the seal member and the inner contact surface can be further improved. Developer leakage can be further suppressed.

  In the developing device having the inner contact surface and the outer contact surface, the seal member can be configured not to be bonded to the installation surface.

  According to this, for example, the seal member can be easily attached to the frame, and the developing device can be easily assembled, as compared with the configuration in which the seal member is installed after the adhesive is applied to the installation surface. it can. Moreover, the cost of the sealing member can be reduced as compared with the configuration in which the adhesive layer is provided on the sealing member.

  According to the present invention, developer leakage can be suppressed in the configuration in which the end of the seal member extends to the outside of the end of the developing roller.

FIG. 2 is a diagram illustrating a schematic configuration of a laser printer in which a developing cartridge as an example of a developing device is used. It is sectional drawing of a process cartridge. FIG. 3 is an exploded perspective view of a developing cartridge. It is an expansion perspective view of the installation surface and seal member concerning a 1st embodiment. It is a figure which shows the structure of the left end part vicinity of the developing roller which concerns on 1st Embodiment. FIG. 5A is a diagram illustrating a state in which the seal member is assembled to the frame in the developing cartridge according to the first embodiment, FIG. 7B is a diagram illustrating the seal member according to the modification, and a configuration near the end of the developing roller according to the comparative example. FIG. It is an expansion perspective view of the installation surface and seal member which concern on 2nd Embodiment. It is an expansion perspective view of the installation surface and seal member concerning a 3rd embodiment. FIG. 10A is a diagram showing a configuration near the left end of a developing roller according to a fourth embodiment, and FIG. It is the figure (a) which shows the installation surface and seal member which concern on 5th Embodiment, and the figure (b) which shows the state which assembled | attached the developing roller. It is a figure which shows the structure of the left end part vicinity of the developing roller which concerns on 6th Embodiment. It is a figure which shows the structure of the left end part vicinity of the developing roller which concerns on 7th Embodiment. It is a figure which shows the structure of the left end part vicinity of the developing roller which concerns on 8th Embodiment. It is a figure which shows the structure of the left end part vicinity of the developing roller which concerns on a modification.

[First Embodiment]
Next, the first embodiment will be described in detail with reference to the drawings as appropriate. In the following description, first, a schematic configuration of a laser printer in which the developing device according to the embodiment is used will be described, and then a detailed configuration of the developing device will be described. In the following description, the direction will be described with reference to the user who uses the laser printer 1. Specifically, the left side of FIG. 1 as viewed from the user is “front”, the right side of FIG. 1 as viewed from the user is “rear”, and the front side of FIG. 1 is “right”. ”, The left side of the page is“ left ”. Further, the vertical direction in FIG.

<Schematic configuration of laser printer>
As shown in FIG. 1, the laser printer 1 includes a feeder unit 4 for feeding a sheet 3 into a main body casing 2, an image forming unit 5 for forming an image on the sheet 3, and the like.

  The feeder unit 4 includes a paper feed tray 6 that is detachably attached to the bottom of the main body casing 2, a paper pressing plate 7 provided in the paper feed tray 6, and various types that carry the paper 3 and remove paper dust. The roller 11 is mainly provided. In the feeder unit 4, the sheet 3 in the sheet feeding tray 6 is moved upward by the sheet pressing plate 7 and conveyed to the image forming unit 5 by various rollers 11.

  The image forming unit 5 includes a scanner unit 16, a process cartridge 17, a fixing unit 18, and the like.

  The scanner unit 16 is provided at an upper portion in the main body casing 2 and includes a laser light emitting unit (not shown), a polygon mirror 19 that is rotationally driven, lenses 20 and 21, reflecting mirrors 22, 23, and 24. In the scanner unit 16, the laser beam is irradiated on the surface of the photosensitive drum 27 by high-speed scanning through a path indicated by a chain line in the drawing.

  The process cartridge 17 is configured to be detachably attached to the main casing 2 by appropriately opening a front cover 2A provided on the front side of the main casing 2. The process cartridge 17 mainly includes a developing cartridge 28 as an example of a developing device and a drum unit 39.

  The developing cartridge 28 is detachably attached to the main casing 2 while being attached to the drum unit 39. As shown in FIG. 2, the developing cartridge 28 mainly includes a developing roller 31, a layer thickness regulating blade 32, a supply roller 33, and an accommodating portion 34 that accommodates toner as an example of a developer.

  In the developing cartridge 28, the toner in the container 34 is stirred by the rotating agitator 34 </ b> A and then supplied to the developing roller 31 by the supply roller 33. The toner supplied to the developing roller 31 enters between the layer thickness regulating blade 32 and the developing roller 31 as the developing roller 31 rotates, and is carried on the developing roller 31 as a thin layer having a constant thickness. .

  The drum unit 39 mainly includes a photosensitive drum 27, a charger 29, and a transfer roller 30. In the drum unit 39, the surface of the photosensitive drum 27 is uniformly charged by the charger 29 and then exposed by high-speed scanning of the laser beam from the scanner unit 16, whereby image data is formed on the photosensitive drum 27. A based electrostatic latent image is formed.

  Thereafter, the toner carried on the developing roller 31 is supplied to the photosensitive drum 27, whereby a toner image is formed on the photosensitive drum 27. Then, the sheet 3 is conveyed between the photosensitive drum 27 and the transfer roller 30, whereby the toner image on the photosensitive drum 27 is transferred to the sheet 3.

  As shown in FIG. 1, the fixing unit 18 mainly includes a heating roller 41 and a pressure roller 42 that is disposed to face the heating roller 41 and pressurizes the heating roller 41. In the fixing unit 18, the toner transferred onto the paper 3 is thermally fixed while the paper 3 passes between the heating roller 41 and the pressure roller 42. The paper 3 thermally fixed by the fixing unit 18 is discharged onto a paper discharge tray 46 by a paper discharge roller 45.

<Detailed configuration of developing cartridge>
2 and 3, the developing cartridge 28 further includes a lower film 35, a frame 100, and a seal member 200 in addition to the developing roller 31, the layer thickness regulating blade 32, the supply roller 33, and the like. ing.

  In the following description, the rotation axis direction of the developing roller 31 corresponding to the left-right direction is referred to as “rotation axis direction”, the radial direction of the developing roller 31 is referred to as “radial direction”, and the rotation direction of the developing roller 31 ( 2) (refer to the arrow in FIG. 2) is referred to as “rotation direction”.

  The developing roller 31 mainly includes a shaft portion 31A and a roller main body 31B configured to carry toner on the surface thereof. The roller body 31B is formed by covering the surface of the shaft portion 31A with conductive rubber or the like.

  The layer thickness regulating blade 32 contacts the surface of the roller body 31B of the rotating developing roller 31 and scrapes off excess toner adhering to the surface of the roller body 31B, thereby reducing the amount of toner carried on the roller body 31B. A member configured to be regulated. The layer thickness regulating blade 32 mainly includes a plate-like member 32A formed of sheet metal and a contact member 32B formed of rubber and contacting the roller body 31B, and is fixed to the frame 100 by screws 38. ing.

  The lower film 35 is a sheet-like member made of a resin such as polyethylene terephthalate (PET), and is arranged in a state of extending in the rotation axis direction between the developing roller 31 and the frame 100 and in contact with the lower portion of the roller body 31B. ing. By providing such a lower film 35, toner leakage from between the lower portion of the roller body 31B and the frame 100 is suppressed.

  As shown in FIG. 3, the frame 100 is a member that forms the accommodating portion 34 and supports the developing roller 31, the layer thickness regulating blade 32, the supply roller 33, and the like. The frame 100 rotatably supports the developing roller 31, the supply roller 33, and the like. The frame 100 includes an opening 110 that is long in the rotational axis direction for supplying the toner in the container 34 to the developing roller 31 via the supply roller 33, an installation surface 120 formed on each of the left and right sides of the opening 110, and an inner contact It mainly has a contact surface 130 and an outer contact surface 140.

  4 and 5 show a configuration in the vicinity of the left installation surface 120. FIG. In the present embodiment, since the configuration near the installation surface 120 is substantially the same, the configuration near the installation surface 120 on the right side is not shown.

  As shown in FIGS. 4 and 5, the installation surface 120 is a surface on which the seal member 200 is installed facing the seal member 200 in the radial direction (corresponding to the vertical direction in FIG. 5). In the present embodiment, the installation surface 120 includes a first surface 121 and a second surface 122 disposed adjacent to the outer side in the rotation axis direction than the first surface 121. The first surface 121 and the second surface 122 are formed as surfaces that are substantially parallel to the rotation axis direction and long in the rotation direction.

  The second surface 122 is provided so that the end 31E in the rotation axis direction of the roller body 31B of the developing roller 31 is located within the width W2 in the rotation axis direction. The second surface 122 is disposed on the inner side (position closer to the developing roller 31) than the first surface 121 in the radial direction. Specifically, the second surface 122 is formed as a surface that is one step higher than the first surface 121. That is, in the present embodiment, the installation surface 120 has a step 125 between the first surface 121 and the second surface 122.

  The inner contact surface 130 is a surface located inside the installation surface 120 in the rotation axis direction. Specifically, the inner contact surface 130 is a side surface of the film attachment portion 105 that is long in the rotation axis direction to which the lower film 35 is attached, and from the end on the inner side in the rotation axis direction of the installation surface 120 (first surface 121). It is formed as a plane (plane along the radial direction) that extends inward in the radial direction and is substantially parallel to the radial direction. The inner contact surface 130 is in contact with an inner end 201 that is an inner end in the rotation axis direction of a seal member 200 described later.

  The outer contact surface 140 is a surface that is positioned outside the installation surface 120 in the rotation axis direction and faces the inner contact surface 130. Specifically, the outer abutting surface 140 is a surface on the inner side in the rotational axis direction of the protruding portion 102 projecting inward from the inner surface in the rotational axis direction of the side wall 101 of the frame 100, and is the installation surface 120 (second surface). 122) is formed as a plane substantially parallel to the inner contact surface 130 that extends radially inward from the outer end in the rotational axis direction. The outer abutment surface 140 abuts on the outer end 202 which is the outer end of the seal member 200 in the rotation axis direction.

  In this embodiment, the seal member 200 has the inner end 201 in contact with the inner contact surface 130 and the outer end 202 in contact with the outer contact surface 140. It is arranged in a state sandwiched between.

  The seal member 200 is a member for suppressing toner leakage from between both ends of the developing roller 31 and the frame 100, and is disposed between both ends of the developing roller 31 and the frame 100. Specifically, the seal member 200 has the outer end 202 extending outside the end 31E in the rotation axis direction of the roller body 31B in the rotation axis direction, and the inner end 201 side on the end of the roller body 31B and the frame 100. It is arrange | positioned between the installation surfaces 120 of.

  The seal member 200 mainly includes an elastic member 210 and a contact member 220 disposed between the elastic member 210 and the developing roller 31.

  The elastic member 210 is provided for the purpose of bringing the contact member 220 into close contact with the developing roller 31 by a restoring force when being crushed, and is made of an elastically deformable material such as urethane sponge.

  The contact member 220 is a member that contacts the roller body 31B. For the purpose of reducing the sliding resistance with the roller body 31B in order to smoothly rotate the developing roller 31, the contact member 220 is made of, for example, a woven fabric such as a pile fabric, a nonwoven fabric such as a felt, a resin film, It is formed from resin tape.

  The seal member 200 is installed on the installation surface 120 in a state of being bonded to the second surface 122 and not bonded to the first surface 121. In addition, the adhesion method of the sealing member 200 and the 1st surface 121 is not specifically limited, For example, it can adhere | attach using an adhesive agent, a double-sided tape, etc.

Next, the effect of this embodiment comprised as mentioned above is demonstrated.
As shown in FIG. 6C as a comparative example, when the installation surface 920 is a flush surface, the outer end 202 of the seal member 200 extends beyond the end 31E of the roller body 31B of the developing roller 31. When the developing roller 31 is attached to the frame 100 and pressed against the seal member 200, a relatively large pressing force is applied to the outer end portion of the seal member 200 from the end 31E of the roller body 31B. The outer edge of the is crushed.

  Then, when the sealing member 200 pushes the end 31E of the roller body 31B by the restoring force of the sealing member 200, a force is exerted on the sealing member 200 to move outward in the rotation axis direction indicated by an arrow. In this state, when the developing roller 31 rotates, the contact member 220 side of the seal member 200 moves outward in the rotation axis direction, and a gap is formed between the inner end 201 and the inner contact surface 130, and toner leaks from the gap. there is a possibility. Such a possibility becomes conspicuous when the diameter of the end portion of the roller body 31B is larger than the slightly inner portion.

  As shown in FIG. 6A, in the present embodiment, the outer second surface 122 is higher by one step than the inner first surface 121, so that the seal member 200 can be inclined and disposed. At this time, the inner end of the seal member 200 is crushed and pressed against the inner contact surface 130, and the developing roller 31 is assembled as shown in FIG. Adhesion between 200 and the inner contact surface 130 can be improved. Further, even if the seal member 200 is slightly displaced outward when the developing roller 31 rotates, the adhesiveness between the seal member 200 and the inner contact surface 130 is restored by returning the crushed portion to the original shape. Can be secured. Thereby, toner leakage can be suppressed.

  In this embodiment, since the frame 100 has the inner contact surface 130 and the outer contact surface 140, the ends 201 and 202 of the seal member 200 are brought into contact with the inner contact surface 130 and the outer contact surface 140. Thus, the position of the seal member 200 in the rotation axis direction can be determined. Further, in the present embodiment, since the seal member 200 is sandwiched between the inner contact surface 130 and the outer contact surface 140, the positional deviation of the seal member 200 can be further suppressed, and toner leakage can be further reduced. Can be suppressed.

  In the present embodiment, since the seal member 200 is not bonded to the first surface 121, the portion facing the first surface 121 can be easily deformed. Can be pressed against the inner contact surface 130 in a more compressed state, and the adhesion between the seal member 200 and the inner contact surface 130 can be further enhanced. Further, since the seal member 200 is bonded to the second surface 122, the positional deviation itself of the seal member 200 can be suppressed. As a result, toner leakage can be further suppressed.

  As shown in FIG. 6B, the seal member 200 approaches the inner side in the rotational axis direction from the radially outer side toward the inner side in a state before the inner end 201 of the seal member 200 contacts the inner contact surface 130. Such an inclined shape (an inclined shape extending to the left side from the lower side to the upper side in FIG. 6) may be provided. According to such a configuration, the inner end portion of the seal member 200 can be pressed against the inner contact surface 130 in a more compressed state, so that the adhesion between the seal member 200 and the inner contact surface 130 is improved. Can be further increased, and toner leakage can be further suppressed.

[Second Embodiment]
Next, a second embodiment will be described. In the embodiments described below, including this embodiment, components different from those of the first embodiment will be mainly described in detail, and the same components as those described in the above will be denoted by the same reference numerals. The description will be omitted.

As shown in FIG. 7, the second surface 122 is provided between the upstream portion 122A on the upstream side in the rotational direction indicated by the arrow, the downstream portion 122B on the downstream side in the rotational direction, and the upstream portion 122A and the downstream portion 122B. And a recess 122C.
The upstream portion 122 </ b> A and the downstream portion 122 </ b> B, which are part of the second surface 122, are surfaces that are disposed on the inner side of the first surface 121 in the radial direction, specifically, 1 with respect to the first surface 121. It is formed as a surface at a stepped position.

  The concave portion 122C is formed as a surface that is recessed radially outward from the upstream portion 122A and the downstream portion 122B, specifically, a surface that is one step lower than the upstream portion 122A and the downstream portion 122B. Supplementally, in the present embodiment, the recess 122 </ b> C is formed as a surface flush with the first surface 121.

  In this embodiment, when the seal member 200 and the developing roller 31 are assembled to the frame 100 and the seal member 200 receives a pressing force from the end 31E of the roller body 31B, a part of the seal member 200 (hatched) is added. The vicinity of the portion) enters the recess 122C of the second surface 122, so that the length of the portion that receives a large pressing force from the end 31E can be shortened. As a result, the force acting on the seal member 200 to move outward in the rotational axis direction can be weakened, so that the positional deviation of the seal member 200 can be suppressed and toner leakage can be further suppressed.

  In the present embodiment, the recess 122C is flush with the first surface 121. However, the present invention is not limited to this, and the recess is not limited to the first portion as long as it is at a position lower than the upstream portion and the downstream portion. The surface may be a surface at a higher position than the surface, or may be a surface at a lower position than the first surface.

[Third Embodiment]
Next, a third embodiment will be described.
As shown in FIG. 8, the seal member 200 has a first portion 203 that faces the first surface 121 and a second portion 204 that faces the second surface 122.
The first portion 203 is formed to be long in the rotation direction indicated by the arrow corresponding to the first surface 121 extending in the rotation direction of the developing roller 31.

  The entire length (L21 + L22) of the second portion 204 is shorter than the length (L11) of the first portion 203 in the rotation direction. Specifically, the second portion 204 is formed so as to extend from the upstream side portion and the downstream side portion in the rotation direction toward the outer side in the rotation axis direction among the side surfaces on the outer side in the rotation axis direction of the first portion 203. It is not formed in the central part of the direction. As a result, the seal member 200 is formed in a U-shape having a recess that is recessed toward the inside in the rotation axis direction at the center of the second portion 204 in the rotation direction.

  In this embodiment, when the seal member 200 and the developing roller 31 are assembled to the frame 100, the length of contact between the second portion 204 and the end 31E of the roller body 31B can be shortened. As a result, it is possible to weaken the force acting on the seal member 200 to move outward in the rotational axis direction, and to suppress the positional deviation of the seal member 200, so that toner leakage can be further suppressed.

  In the present embodiment, the shape of the seal member is not particularly limited as long as the length of the second portion is shorter than the length of the first portion in the rotation direction. For example, in the form shown in FIG. 8, the second portion 204 is divided into two in the rotation direction, but is not limited to this, and is formed in a comb-teeth shape divided into three or more in the rotation direction. May be. Further, the seal member has a T-shape, specifically, the second portion extends from only the central portion in the rotation direction toward the outside in the rotation axis direction, out of the side surfaces of the first portion in the rotation axis direction outside. And may be formed in a shape that is not formed in the upstream portion and the downstream portion in the rotational direction. Further, the seal member may be formed in an L shape.

[Fourth Embodiment]
Next, a fourth embodiment will be described.
As shown in FIGS. 9A and 9B, the seal member 200 has a slit 240 on the surface that contacts the roller body 31B. The slit 240 is formed by making a cut in the seal member 200. Specifically, the slit 240 is formed with a depth from the surface of the contact member 220 to the middle of the elastic member 210. The slit 240 is formed from the upstream end to the downstream end of the seal member 200 in the rotational direction so as to extend along the rotational direction indicated by the arrow. In addition, the slit 240 is inside the step 125 that is the boundary between the first surface 121 and the second surface 122 in the rotational axis direction, specifically, the step 125 and the center of the portion facing the first surface 121. It is arranged near the step 125 in the range (see the alternate long and short dash line) between the two parts.

  In this embodiment, even when a portion outside the slit 240 of the seal member 200 moves outward when the developing roller 31 rotates, the slit 240 is slightly opened, and thus the slit 240 of the seal member 200 is opened. However, the inner part is less likely to be subjected to a force to move outward. As a result, the adhesion between the inner end 201 and the inner contact surface 130 can be ensured, and toner leakage can be further suppressed.

  Further, in the present embodiment, the slit 240 is arranged on the inner side in the rotation axis direction than the step 125, so that the position shift of the portion of the seal member 200 between the first surface 121 and the roller main body 31B is prevented. Can be suppressed. Thereby, since the adhesiveness of the part facing the 1st surface 121 of the sealing member 200 and the flame | frame 100 or the roller main body 31B can be improved, a toner leak can be suppressed further.

  9A, the slit is located at the same position as the step 125 that is the boundary between the first surface 121 and the second surface 122 in the rotation axis direction (on the one-dot chain line on the right side in the drawing). May be arranged.

[Fifth Embodiment]
Next, a fifth embodiment will be described.
As shown in FIG. 10A, the seal member 200 includes a base member 250 as an example of a first member, and a second member disposed between the base member 250 and the developing roller 31 (specifically, the contact member 220). An elastic member 210 as an example of a member and a contact member 220 are provided.

  The base member 250 is a member that is supported by the installation surface 120, and is formed of a material that is harder than the elastic member 210 and hardly elastically deformed, for example, a resin such as PET. As shown in FIG. 10B, the base member 250 is disposed between the inner contact surface 130 and the outer contact surface 140 when the seal member 200 is installed on the installation surface 120. In the present embodiment, the seal member 200 (base member 250) may or may not be bonded to the installation surface 120.

  According to the present embodiment as described above, the rigid base member 250 is sandwiched between the inner contact surface 130 and the outer contact surface 140, so that the displacement of the seal member 200 can be suppressed. Thereby, toner leakage can be further suppressed.

[Sixth Embodiment]
Next, a sixth embodiment will be described.
As shown in FIG. 11, the installation surface 120 is formed as an inclined surface that approaches the radially inner side from the inner end of the first surface 121 in the rotation axis direction toward the outer end of the second surface 122. . That is, the entire installation surface 120 is formed as an inclined surface that approaches the radially inner side as it goes from the inner side to the outer side in the rotational axis direction.

  The seal member 200 is bonded to the second surface 122. In other words, in this embodiment, the seal member 200 is bonded to the installation surface 120 at a portion facing the end 31E of the roller body 31B, and the surface to which the seal member 200 is bonded becomes the second surface 122, and the second surface 122 The surface to which the seal member 200 on the inner side in the rotation axis direction than the surface 122 is not bonded becomes the first surface 121.

  In this embodiment, a force directed inward in the rotational axis direction due to the inclination of the installation surface 120 acts on the seal member 200 due to the inclination of the installation surface 120, particularly with respect to the portion sandwiched between the roller body 31 </ b> B and the installation surface 120. . As a result, the adhesion between the inner end 201 and the inner contact surface 130 can be enhanced, so that toner leakage can be further suppressed.

[Seventh Embodiment]
Next, a seventh embodiment will be described.
As shown in FIG. 12, the installation surface 120 is formed such that the first surface 121 is a surface substantially parallel to the rotation axis direction (a surface along the rotation axis direction) as in the first embodiment. On the other hand, the second surface 122 is formed as an inclined surface that approaches the radially inner side from the outer end of the first surface 121 in the rotation axis direction toward the outer side.

  In such an embodiment, the seal member 200 is substantially applied to the seal member 200 between the first surface 121 and the roller main body 31B while applying a force toward the inner side in the rotation axis direction due to the inclination of the second surface 122. A uniform pressing force can be applied. As a result, the adhesion between the seal member 200 and the inner contact surface 130 or the roller main body 31B can be enhanced, so that toner leakage can be further suppressed.

[Eighth Embodiment]
Next, an eighth embodiment will be described.
As shown in FIG. 13, the installation surface 120 is formed with a protrusion 127 that protrudes radially inward (upper side in FIG. 13) at a position facing the end 31E of the roller body 31B of the developing roller 31. . The protrusion 127 may be a boss shape or a rib shape extending in the rotation direction.

The first surface 121 is a surface located on the inner side in the rotation axis direction than the protrusion 127.
The second surface 122 is the surface of the protrusion 127, and the end 31 </ b> E is located within the width W <b> 7 in the rotation axis direction, and is arranged radially inward from the first surface 121.

  In this embodiment, since the protrusion 127 (second surface 122) is narrow in the rotational axis direction, the protrusion 127 bites into the seal member 200 when the seal member 200 and the developing roller 31 are assembled to the frame 100. It becomes. Thereby, since the position shift of the seal member 200 is suppressed, toner leakage can be further suppressed.

  Although the embodiment has been described above, the present invention is not limited to the embodiment. About a concrete structure, it can change suitably in the range which does not deviate from the meaning of invention as follows.

  In the embodiment, as shown in FIG. 5, the installation surface 120 having the first surface 121 and the second surface 122 having different radial positions (heights) is formed on the frame 100 in advance. However, the present invention is not limited to this. For example, as illustrated in FIG. 14, the frame 100 has a flush facing surface 103 that faces the seal member 200, and a thick double-sided tape 150 or the like is attached to a portion of the facing surface 103 on the outer side in the rotation axis direction. The installation surface 120 having the first surface 121 and the second surface 122 having different heights may be formed.

  In the embodiment, the seal member 200 is bonded only to the second surface 122. However, the present invention is not limited to this. For example, the seal member is bonded to both the first surface and the second surface. Also good. Further, referring to FIG. 5, in a configuration in which the seal member 200 is disposed between the inner contact surface 130 and the outer contact surface 140, the seal member 200 is installed on the installation surface 120. It does not need to be adhered to the. According to this, for example, the seal member can be easily attached to the frame as compared with the configuration in which the seal member is installed after the adhesive is applied to the installation surface. Can do. Moreover, the cost of the sealing member can be reduced as compared with the configuration in which the adhesive layer is provided on the sealing member.

  In the embodiment, the outer contact surface 140 is a surface on the inner side in the rotation axis direction of the protrusion 102 provided on the side wall 101 of the frame 100, but is not limited thereto. For example, referring to FIG. 4, in a configuration in which the projecting portion 102 is not provided on the frame 100, the outer contact surface may be a surface on the inner side in the rotation axis direction of the side wall 101 of the frame 100. Moreover, in the said embodiment, although the flame | frame 100 had the outer side contact surface 140, it is not limited to this, For example, the structure which does not have an outer side contact surface may be sufficient.

  In the first embodiment and the like, the seal member 200 has a two-layer structure including the elastic member 210 and the contact member 220. However, the present invention is not limited to this. For example, the seal member may have a single-layer structure. A multilayer structure of three or more layers may be used.

  In the embodiment, the developing cartridge 28 is exemplified as the developing device. However, the developing device 28 is not limited to this. For example, the developing device may further include a photosensitive drum, a charger, and the like. Specifically, the developing device may have the same configuration as the process cartridge 17 of the above embodiment. At this time, the developing cartridge and the drum unit may be configured to be detachable or may be configured integrally. In addition, the developing cartridge as the developing device may be configured such that a portion where the developing roller and the layer thickness regulating blade are disposed and a storage portion (toner box) for storing the toner are detachable.

  In the above embodiment, the laser printer 1 capable of forming only a monochrome image is exemplified as an image forming apparatus in which the developing device of the present invention is used. However, the present invention is not limited to this, and for example, a printer capable of forming a color image. There may be. The image forming apparatus is not limited to a printer, and may be, for example, a copier or a multi-function machine including a document reading apparatus such as a flat bed scanner.

28 Developing cartridge 31 Developing roller 31B Roller body 31E End 100 Frame 120 Installation surface 121 First surface 122 Second surface 125 Step 130 Inner contact surface 140 Outer contact surface 200 Seal member 201 Inner end 202 Outer end

Claims (13)

A developing roller having a roller body configured to carry a developer;
A frame that rotatably supports the developing roller;
An elastically deformable seal member disposed between both ends of the roller body and the frame;
The seal member has an outer end of the seal member positioned outside an end of the roller body in the rotation axis direction in the rotation axis direction of the developing roller,
The frame includes an installation surface on which the seal member is installed, and an inner contact surface that is located on the inner side of the installation surface in the rotation axis direction and contacts an inner end of the seal member,
The installation surface includes a first surface and a second surface disposed on the outer side in the rotational axis direction than the first surface,
The second surface is provided such that an end of the roller body in the rotational axis direction is located within a width of the second surface in the rotational axis direction,
At least a part of the second surface is disposed on the inner side of the first surface in the radial direction of the developing roller.   The developing device according to claim 1, wherein the frame has an outer abutting surface that is located outside the installation surface in the rotation axis direction and abuts on an outer end of the seal member.   The installation surface is an inclined surface that approaches the radially inner side from the inner end of the first surface toward the outer end of the second surface in the rotation axis direction. Alternatively, the developing device according to claim 2. The first surface is a surface along the rotation axis direction;
The said 2nd surface is an inclined surface which approaches the said radial inside as it goes to the outer side from the outer end of the said 1st surface in the said rotation axis direction, The Claim 1 or Claim 2 characterized by the above-mentioned. Development device.   The developing device according to claim 1, wherein the installation surface has a step between the first surface and the second surface.   The developing device according to claim 1, wherein the seal member is bonded to the second surface and is not bonded to the first surface.   The second surface is provided between an upstream portion on the upstream side in the rotational direction of the developing roller, a downstream portion on the downstream side in the rotational direction, and the upstream portion and the downstream portion. The developing device according to claim 1, further comprising a concave portion that is recessed outward in the radial direction. The seal member has a first portion facing the first surface, and a second portion facing the second surface,
8. The developing device according to claim 1, wherein a length of the second portion is shorter than a length of the first portion in a rotation direction of the developing roller. 9.   The developing device according to claim 1, wherein the seal member has a slit extending in a rotation direction of the developing roller on a surface that contacts the roller main body.   The developing device according to claim 9, wherein the slit is arranged at the same position as or inward of the boundary between the first surface and the second surface in the rotation axis direction. . The seal member includes a first member supported on the installation surface, and a second member disposed between the first member and the developing roller,
The developing device according to claim 2, wherein the first member is harder than the second member and is disposed between the inner contact surface and the outer contact surface. The inner contact surface is a plane along the radial direction,
The inner end of the seal member has a shape that approaches the inner side in the rotational axis direction from the outer side in the radial direction toward the inner side in a state before coming into contact with the inner abutting surface. The developing device according to any one of claims 1 to 11.   The developing device according to claim 2, wherein the seal member is not bonded to the installation surface.

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