JP6646246B2 - Developing device, process cartridge, and image forming device - Google Patents

Description

  The present invention relates to a developing device for developing a latent image formed on an image carrier, and a process cartridge and an image forming apparatus provided with the same, and particularly, faces a developing roller downstream or upstream of a developing area. The present invention relates to a developing device, a process cartridge, and an image forming apparatus provided with a casing member as described above.

  2. Description of the Related Art Conventionally, in a developing device installed in an electrophotographic image forming apparatus such as a copying machine, a printer, a facsimile, or a multifunction peripheral thereof, a developing roller is provided so as to face a photosensitive drum (image carrier). A casing member (upper case) and a developing roller installed to cover the developing roller on the downstream side of the developing area for the purpose of reducing toner scattering from the opening where a part of the (developer carrier) is exposed. A technique is known in which a gap (casing gap) is set to a desired value (for example, see Patent Document 1).

The conventional developing device covers a part of the outer peripheral surface of the developing roller with respect to a first casing member (lower case) that holds components such as a developing roller so that a desired casing gap is formed. The position of the formed second casing member (upper case) was adjusted, and the second casing member was fixed to the first casing member at the adjusted position by screwing.
Therefore, it takes time and effort to assemble the developing device, and the casing gap varies depending on the operator.

  SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problem, and a second casing member that covers a part of an outer peripheral surface of a developing roller is fixed to a first casing member that holds a developing roller. When a casing gap is formed between the developing roller and the second casing member, the assemblability of the second casing member to the first casing member is relatively good, and the casing gap is less likely to be varied by an operator. It is an object of the present invention to provide a developing device, a process cartridge, and an image forming apparatus in which a casing gap is formed stably and with high precision.

According to a first aspect of the present invention, there is provided a developing device for developing a latent image formed on a surface of an image carrier traveling in a predetermined direction, wherein a developing area is opposed to the image carrier. Forming a developing roller that carries the developer and rotates in a predetermined direction, a first casing member that rotatably holds the developing roller, and a downstream side in the rotation direction of the developing roller with respect to the developing area. A second casing member that covers a part of the outer peripheral surface of the developing roller so as to face the outer peripheral surface of the developing roller with a gap on at least one side of the upstream side in the rotation direction, and the first casing member, protrusion protruding toward the second casing member is formed, the second casing member, the while fitting the projecting portion, the second I abutting on the projecting portion Case Comprises a recess grayed member is restricted from displacement in a side of the developing roller, the both ends in the longitudinal direction corresponding to the rotation axis direction of the developing roller and the projecting portion and the recess, wherein the developing roller Inclined portions that are inclined in a predetermined direction with respect to the rotating direction are respectively formed , provided so that the boundary between the protruding portion and the concave portion is exposed at a position where the developer carried on the developing roller contacts, The inclined portion is provided at the exposed boundary .

  According to the invention, the second casing member that covers a part of the outer peripheral surface of the developing roller is fixed to the first casing member that holds the developing roller, and the casing is provided between the developing roller and the second casing member. When forming the gap, the assemblability of the second casing member to the first casing member is relatively good, the casing gap is hardly varied by the operator, and the desired casing gap is formed stably and with high precision. , A developing device, a process cartridge, and an image forming apparatus.

1 is an overall configuration diagram illustrating an image forming apparatus according to an embodiment of the present invention. FIG. 3 is a configuration diagram illustrating a part of an image forming unit in an enlarged manner. FIG. 2 is a schematic perspective view illustrating a developing device. 3A is a cross-sectional view showing a central portion in the longitudinal direction, and FIG. 3B is a cross-sectional view showing an end portion in the longitudinal direction, on the downstream side of the developing region in the developing device. It is a top view which shows the part which a 2nd casing member fits in a 1st casing member in a longitudinal direction. (A) A schematic perspective view showing a state immediately before the recess of the second casing member is fitted to the projection of the first casing member, and (B) a recess of the second casing member at the projection of the first casing member. FIG. 2 is a schematic perspective view showing a fitted state. (A) An enlarged front view showing a state in which a concave portion of a second casing member is fitted to a projecting portion of a first casing member, and (B) a second casing member at a projecting portion of a first casing member as a comparative example. And FIG. 4 is an enlarged front view showing a state in which the concave portions are fitted. FIG. 9 is a configuration diagram illustrating a part of an image forming unit as a modification example in an enlarged manner.

Embodiment.
Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. In each of the drawings, the same or corresponding portions are denoted by the same reference characters, and a repeated description thereof will be appropriately simplified or omitted.

First, the overall configuration and operation of the image forming apparatus will be described with reference to FIGS.
In FIG. 1, reference numeral 100 denotes a printer as an image forming apparatus, 6 denotes a process cartridge (image forming unit) for forming a toner image (image) on the photosensitive drum 1, and 7 denotes image information input from an input device such as a personal computer. An exposure unit (writing unit) for irradiating the photosensitive drum 1 with exposure light L based on the above, an electrostatic elimination light source (static elimination means) 8 for eliminating the surface potential of the photosensitive drum 1, and a carrier 9 carried on the photosensitive drum 1 A transfer roller (transfer member) for transferring the applied toner image to a recording medium P conveyed to a transfer position; 12, a paper supply unit (paper cassette) containing a recording medium P such as transfer paper; A fixing device for fixing the unfixed image on the P, a fixing roller 21 provided in the fixing device 20, a pressure roller 22 provided in the fixing device 20, and a photosensitive drum 1 and the transfer roller 9 corresponding to 45. Transfer position (transfer Tsu registration rollers for conveying the recording medium P toward the flop) (timing rollers), showing the.

  Here, referring to FIGS. 1 and 2, the process cartridge 6 includes a photosensitive drum 1 as an image carrier, a charging unit 4 (charging roller), a developing device 5 (developing unit), and a cleaning unit 2. The (cleaning device) and the recycled toner paths 3 and 29 are integrally configured as a unit. The process cartridge 6 is detachably (exchangeably) installed in the image forming apparatus main body 100.

More specifically, the photoreceptor drum 1 as an image carrier is a negatively charged organic photoreceptor having a photosensitive layer or the like provided on a drum-shaped conductive support. Although not shown, the photosensitive drum 1 has a conductive support as a base layer, in which an undercoat layer as an insulating layer, a charge generation layer as a photosensitive layer, and a charge transport layer are sequentially laminated. The photosensitive drum 1 is rotated (runs) in the counterclockwise direction in FIG. 1 by rotational driving by a drive motor (not shown).
The charging unit 4 is a charging roller in which a conductive core is coated with an elastic layer having a medium resistance around the outer periphery thereof, and is in contact with the photosensitive drum 1. A predetermined voltage (charging bias) is applied to the charging unit 4 from a power supply unit (not shown), thereby uniformly charging the surface of the opposing photosensitive drum 1.

The developing device 5 (developing unit) mainly includes a developing roller 51 (developer carrying member) facing the photosensitive drum 1, two conveying screws 53 (conveying member) arranged in parallel via a partition member, and a developing roller. And a doctor blade 52 (developer regulating member) opposing to 51.
The developing roller 51 includes a magnet that is fixed inside and forms a magnetic pole on the roller peripheral surface, and a sleeve that rotates around the magnet. A plurality of magnetic poles are formed on the developing roller 51 (sleeve) by the magnet, and the developer is carried on the developing roller 51.
The transport screw 53 has a screw portion spirally wound around a rotating shaft portion, and the developer accommodated in the developing device 5 is arranged in the longitudinal direction (the direction perpendicular to the paper surface of FIGS. 1 and 2). ) To form a circulation path for the developer.
The developing device 5 contains a two-component developer composed of a carrier and a toner. Although not shown, a toner container (containing new toner) detachably installed separately from the process cartridge 6 is connected above the developing device 5.

The developing device 5 configured as described above operates as follows.
The sleeve of the developing roller 51 is rotating in a predetermined direction (clockwise direction in FIG. 1). The developer carried on the developing roller 51 by the magnetic field formed by the magnet moves on the developing roller 51 as the sleeve rotates. Here, the developer in the developing device 5 is adjusted so that the ratio (toner concentration) of the toner in the developer is within a predetermined range (appropriately through a toner supply port (not shown) from the toner container). Toner is supplied).
Thereafter, the toner replenished into the developer accommodating portion is circulated through the two developer accommodating portions separated by the partition member except for both ends in the longitudinal direction while being mixed and stirred with the developer by the two conveying screws 53. (This is the movement in the direction perpendicular to the paper surface of FIGS. 1 and 2). The toner in the developer is attracted to the carrier by frictional charging with the carrier, and is carried on the developing roller 51 together with the carrier by a magnetic force formed on the developing roller 51.

The developer carried on the developing roller 51 is conveyed clockwise in FIG. 1 and reaches the position of the doctor blade 52. Then, the developer on the developing roller 51 is transported to a position facing the photosensitive drum 1 (a development area) after the developer amount is adjusted to an appropriate amount at this position. Then, the electric field is formed on the photosensitive drum 1 by an electric field formed in the developing area (the electric field formed by the developing bias applied to the developing roller 51 and the potential of the latent image on the photosensitive drum 1). The toner is attracted to the latent image thus formed. Thereafter, the developer remaining on the developing roller 51 reaches above the developer accommodating portion with the rotation of the sleeve, and is separated from the developing roller 51 at this position.
The developing roller 51 and the transport screw 53 in the developing device 5 receive a driving force from a developing drive motor (not shown) and are driven to rotate.

  Referring to FIGS. 1 and 2, untransferred toner (paper dust and untransferred toner generated from recording medium P) that abuts on photosensitive drum 1 and adheres to the surface of photosensitive drum 1 is attached to cleaning unit 2. The cleaning blade 2a that removes agglomerated matter (aggregated toner), discharge products generated on the photosensitive drum 1 at the time of discharging by the charging unit 4, and additives such as additives added to the toner. The stirring member 2c that stirs and conveys the untransferred toner removed and collected by the cleaning unit 2 and the untransferred toner removed and collected by the cleaning unit 2 in the longitudinal direction (widthwise direction, FIGS. 1 and 2). , A cleaning transport screw 2b for transporting the cleaning screw 2b.

The cleaning blade 2a has a plate-shaped blade body made of a rubber material such as urethane rubber, hydrin rubber, silicone rubber, or fluoro rubber, which is held by a holding plate. In contact. As a result, untransferred toner adhering to the photosensitive drum 1 is mechanically scraped off and collected in the cleaning unit 2. In the present embodiment, the cleaning blade 2a is in contact with the photosensitive drum 1 in a counter direction with respect to the traveling direction (rotation direction) of the photosensitive drum 1.
The stirring member 2c has a stirring portion provided on a rotating shaft portion, and rotates in a predetermined direction by receiving a driving force from a driving motor (not shown).
The cleaning and transporting screw 2b has a screw portion spirally wound around a rotating shaft portion, and rotates in a predetermined direction by receiving a driving force from a driving motor (not shown).

Then, the untransferred toner collected by the cleaning unit 2 is supplied to the developing device 5 as recycled toner via the recycled toner paths 3 and 29.
Specifically, the recycled toner path includes a transport path section 29 (horizontal transport section) provided above the cleaning section 2 (process cartridge 6) and including the transport screw 2b therein, the transport path section 29, and the developing device 5 And a fall path section 3 for relaying the same. The untransferred toner collected inside the cleaning unit 2 flows from an inflow port formed at one end of the transport path unit 29 in the longitudinal direction (perpendicular to the paper surface of FIGS. 1 and 2). Then, the toner is conveyed in the longitudinal direction by the cleaning conveyance screw 2b in the conveyance path portion 29 and flows out from the outlet at the other end in the width direction toward the falling path portion 3. Then, the untransferred toner that has flowed into the falling path unit 3 falls by its own weight on the falling path unit 3, is supplied from the supply port into the developing device 5, and is used as recycled toner in the developing device 5.

With reference to FIGS. 1 and 2, an operation of the image forming apparatus 100 during normal image formation will be described.
First, when image information is transmitted from an input device such as a personal computer to the exposure unit 7 of the image forming apparatus 1, exposure light L (laser light) based on the image information is emitted from the exposure unit 7 onto the photosensitive drum 1. Fired at. In this embodiment, the exposure unit 7 using a known LD light source (laser diode) is used. Specifically, the exposure unit 7 reflects the exposure light L emitted from the LD light source based on the image information on a polygon mirror that rotates at a high speed and scans the exposure light L in the main scanning direction (width direction). Is to form an electrostatic latent image on the surface of the substrate.
On the other hand, the photosensitive drum 1 is rotating in the direction of the arrow (counterclockwise). Then, first, the surface of the photoconductor drum 1 is uniformly charged in a portion facing the charging unit 4 (charging step). Thus, a charging potential (about -900 V) is formed on the photosensitive drum 1. Thereafter, the charged surface of the photosensitive drum 1 reaches the irradiation position of each exposure light L. Then, the potential of the portion irradiated with the exposure light L becomes the latent image potential (about 0 to -100 V), and an electrostatic latent image is formed on the surface of the photosensitive drum 1 (this is an exposure step). .). That is, on the surface of the photosensitive drum 1, a portion irradiated with the exposure light L is formed with a latent image potential (image portion potential) as an image portion (electrostatic latent image), and other portions are formed with a non-image portion ( The charged potential (non-image potential) is maintained as the background portion.

Thereafter, the surface of the photosensitive drum 1 on which the electrostatic latent image is formed reaches a position facing the developing device 5 (developing roller 51). Then, toner is supplied from the developing device 5 onto the photosensitive drum 1, and the latent image on the photosensitive drum 1 is developed to form a toner image (a developing step).
Thereafter, the surface of the photosensitive drum 1 after the developing process reaches a transfer nip (transfer position) with the transfer roller 9. Then, at a transfer nip with the transfer roller 9, the transfer bias applied to the transfer roller 9 (a bias having a polarity different from the polarity of the toner) is applied to the recording medium P conveyed by the registration roller 45. The toner image formed on the body drum 1 is transferred (this is a transfer step).

Then, the surface of the photosensitive drum 1 after the transfer step reaches a position facing the cleaning unit 2. Then, at this position, the untransferred toner (including other attached matter such as paper dust and agglomerated toner) remaining on the photosensitive drum 1 is mechanically removed by the cleaning blade 2a, and the cleaning unit 2 is removed. (This is a cleaning step.)
Then, the surface potential of the photosensitive drum 1 after the cleaning process is reduced by the charge elimination by the charge elimination light K emitted from the charge elimination light source 8, and the surface potential is reset to almost 0V. In the present embodiment, a known LED (LED array) is used as the static elimination light source 8.
Thus, a series of image forming processes on the photosensitive drum 1 is completed.

On the other hand, the recording medium P conveyed to the transfer nip (transfer position) between the photosensitive drum 1 and the transfer roller 9 operates as follows.
First, the uppermost sheet of the recording medium P stored in the sheet feeding unit 12 is fed by a sheet feeding roller 41 toward a transport path.
Thereafter, the recording medium P reaches the position of the registration roller 45. Then, the recording medium P that has reached the position of the registration roller 45 is conveyed toward the transfer nip (transfer roller 9) at a proper timing to align the image with the image formed on the photosensitive drum 1. .

Then, the recording medium P after the transfer step passes through the position of the transfer nip (transfer roller 9), and then reaches the fixing device 20 via a transfer path formed by a transfer guide plate and a fixing guide plate. The recording medium P that has reached the fixing device 20 is fed between the fixing roller 21 and the pressure roller 22, and the image is fixed by the heat received from the fixing roller 21 and the pressure received from both members 21 and 22. You. The recording medium P on which the image has been fixed is sent out from between the fixing roller 21 and the pressure roller 22 (the fixing nip portion), and then discharged from the image forming apparatus main body 100.
Thus, a series of image forming processes is completed.

Hereinafter, the configuration and operation of the developing device 5 that is characteristic in the present embodiment will be described in detail.
As described above, the developing device 5 forms a developing region in opposition to the photosensitive drum 1 (image carrier) with a predetermined gap (developing gap), and carries a predetermined amount of developer. A developing roller 51 that rotates in the direction (clockwise in FIG. 2) is provided.
Here, with reference to FIG. 2 and FIG. 3, the developing device 5 in the present embodiment has two casing members (a first casing member 54 and a second casing member 55) as its exterior (casing). .) Are provided so as to be separable (detachable). That is, the first casing member 54 and the second casing member 55 are connected to form an exterior of the developing device 5.
In the present embodiment, both the first casing member 54 and the second casing member 55 are formed of a resin material such as PC resin or ABS resin having excellent workability and high mechanical strength. The first casing member 54 is formed in a substantially box shape, and the second casing member 55 is formed in a substantially lid shape.

The first casing member 54 rotatably holds the developing roller 51 and the transport screw 53, and fixedly holds the doctor blade 52. The first casing member 54 is a state in which the developing device 5 (the state shown in FIG. ) Is formed as a lower case so as to cover the lower side of the lower case.
More specifically, the shaft portions at both ends in the longitudinal direction of the developing roller 51 and the transport screw 53 are supported on both side portions of the first casing member 54 via bearings. Further, the doctor blade 52 is fixed and held by screwing so as to be placed on the upper part of the partition member of the first casing member 54. Then, the doctor blade 52 forms a minute gap (doctor gap) with the developing roller 51.

  The second casing member 55 is at least one of a downstream side in the rotational direction of the developing roller 51 and an upstream side in the rotational direction of the developing roller 51 with respect to a developing area (an area where the developing roller 51 and the photosensitive drum 1 face each other). , A part of the outer peripheral surface of the developing roller 51 is covered so as to face the outer peripheral surface of the developing roller 51 with a gap (casing gap) therebetween. In the present embodiment, the second casing member 55 has a desired casing gap with respect to the outer peripheral surface of the developing roller 51 on each of the downstream side and the upstream side in the rotation direction of the development roller 51 with respect to the development area. Are formed so as to face each other. Specifically, the second casing member 55 forms a desired downstream casing gap G between the developing roller 51 and the developing region at a position downstream of the developing region in the rotation direction of the developing roller 51, and the second casing member 55 defines a desired downstream casing gap G with respect to the developing region. A desired upstream casing gap is formed between the developing roller 51 and a position upstream of the developing roller 51 in the rotation direction.

More specifically, referring to FIGS. 2 and 3, second casing member 55 is a developing device 5 installed in image forming apparatus main body 100 (shown in FIGS. 2 and 3). An opening X that exposes a part of the developing roller 51 is formed at a position above. The opening X is formed to make the developing roller 51 installed inside the developing device 5 face the photosensitive drum 1 installed outside the developing device 5.
The second casing member 55 is formed so as to cover above the developing device 5 installed in the image forming apparatus main body 100, and functions as an upper case.
Further, in the present embodiment, a sheet-shaped inlet seal 56 made of a flexible material such as polyurethane foam is provided on the upstream side of the developing region in the second casing member 55 so as to slidably contact the surface of the photosensitive drum 1. To prevent the generation of a suction airflow from the opening X toward the inside of the developing device 5.
In the vicinity of the downstream casing gap G, the portion where the first casing member 54 and the second casing member 55 are fitted is preferably formed so as to minimize a step.

  Here, the second casing member 55 is fitted and positioned with respect to the first casing member 54 on at least one of the rotation direction downstream side and the rotation direction upstream side of the developing roller 51 with respect to the developing area. And is fixed by non-fastening. In the present embodiment, the second casing member 55 is fitted and positioned with respect to the first casing member 54 on the downstream side in the rotation direction of the developing roller 51 with respect to the developing area, and is fixed without being fastened. It is configured.

4 to 6 and the like, the first casing member 54 has a projection 54a (abutting portion), two bosses 54b (engaging portion), a wall portion 54c (a regulating portion), Etc. are formed.
The protruding portion 54a is a central portion in the longitudinal direction corresponding to the rotation axis direction of the developing roller 51, as shown in FIGS. 4A (FIG. 3 illustrates the cross section M in FIG. 3), FIGS. Is formed so as to protrude toward the second casing member 55 (upward).
The two boss portions 54b are provided in the longitudinal direction corresponding to the rotation axis direction of the developing roller 51, as shown in FIG. 4B (a cross section N in FIG. 3), and FIGS. Both end portions are formed so as to protrude toward the second casing member 55 (upward).
4 to 6, the wall portion 54c is opposed to the facing surface 55c of the second casing member 55 in the longitudinal direction so that the second casing member 55 is not displaced (moved) away from the developing roller 51. Is regulated.

On the other hand, with reference to FIGS. 4 to 6 and the like, the second casing member 55 includes a concave portion 55a (a portion to be abutted), a hole 55b (a portion to be engaged), an opposing surface 55c (a regulated portion), and the like. Is formed.
The concave portion 55a is fitted to the projecting portion 54a of the first casing member 54, and is regulated such that the second casing member 55 is not displaced (moved) toward the developing roller 51 by hitting the projecting portion 54a. .
The two holes 55b are fitted into the two bosses 54b of the first casing member 54, respectively.
The facing surface 55c faces the wall portion 54c of the first casing member 54, and is regulated so that the second casing member 55 is not displaced (moved) away from the developing roller 51.

Then, the second casing member 55 is detachably installed by being vertically moved with respect to the first casing member 54 in the state shown in FIG. 3, and is disposed on the downstream side in the rotation direction of the developing roller 51 with respect to the developing area. The first casing member 54 is fitted and positioned and fixed without being fastened. That is, in the vicinity where the downstream casing gap G is formed, the second casing member 55 is fitted and positioned and fixed to the first casing member 54 without being screwed.
Therefore, an operation of adjusting the position of the second casing member 55 with respect to the first casing member 54 in order to form the desired downstream casing gap G becomes unnecessary. Therefore, the assemblability of the second casing member 55 with respect to the first casing member 54 is relatively good, and it is difficult for the operator to vary the casing gap G, and the desired casing gap G is formed stably and with high precision. become.

  In the present embodiment, the downstream casing gap G is too large, so that a large suction airflow is generated from the position along the rotation of the developing roller 51 and the toner is not scattered due to an increase in the internal pressure of the developing device 5. Further, the downstream casing gap G is so small that the developer carried by the developing roller 51 at that position is not pressed against the inner wall of the second casing member 55 with a strong force so that the downstream casing gap G is too small. It is set to about 0.3 to 1.0 mm. Since the aimed downstream casing gap G is formed stably and with high precision, the problem of toner scattering from the inside of the developing device 5 to the outside is stably reduced, and the second casing member 55 The problem that the developer adheres to the inner wall of the substrate can be stably reduced.

  In particular, in the present embodiment, the second casing member 55 is basically positioned relative to the first casing member 54 by engagement of the boss portions 54b and the hole portions 55b at both ends in the longitudinal direction, and the second casing member 55 Even if the casing member 55 approaches the developing roller 51 so as to bend in the longitudinal direction and is likely to bend, the bending is limited by the recess 55a abutting against the protruding portion 54a at the center in the longitudinal direction. become. Therefore, the disadvantage that the second casing member 55 is bent and the downstream casing gap G does not become uniform in the longitudinal direction but becomes smaller than the target value at the central portion in the longitudinal direction can be reliably reduced.

  Furthermore, even if the second casing member 55 is likely to bend away from the developing roller 51 so as to bend in the longitudinal direction, the first casing member 54 is sandwiched between the second casing member 55 and the protrusion 54a. Since the wall portion 54c is formed in the longitudinal direction, when the opposing surface 55c abuts on the wall portion 54c, the bending thereof is limited. Therefore, the disadvantage that the second casing member 55 is bent and the downstream casing gap G does not become uniform in the longitudinal direction but becomes larger than the target value at the central portion in the longitudinal direction can be reliably reduced. Note that, in order to improve the detachability of the second casing member 55 with respect to the first casing member 54, the wall portion 54c and the wall portion 54c are kept within an upper limit value of the downstream casing gap G (a limit at which toner scattering does not occur). It can be set so that a minute gap is formed with the facing surface 55c.

  In the present embodiment, the second casing member 55 is fixed to the first casing member 54 without using screw fastening in the vicinity of the portion where the downstream casing gap G is formed. On the other hand, although illustration is omitted, portions other than the portion where the downstream casing gap G is formed (for example, the partition member and the left end wall portion of the first casing member 54 in FIG. , Abut on each other.) In the same manner, the second casing member 55 can be fixed to the first casing member 54 without using screw fastening, or by using patching or screw fastening. Can also be fixed.

Here, as shown in FIGS. 6 and 7A, in the present embodiment, the direction (vertical direction) in which the projecting portion 54a of the first casing member 54 projects toward the second casing member 55 is high. It is formed in a substantially trapezoidal shape so as to be in the vertical direction. The concave portion 55a of the second casing member 55 is formed in a substantially trapezoidal shape so as to match the shape of the projecting portion 54a.
That is, the inclined portion 54a1 inclined at a predetermined angle θ with respect to the direction in which the developing roller 51 rotates (the direction in which the developer carried by the developing roller 51 moves, which is the direction of the arrow in FIG. 7). , 55a1 are formed at both longitudinal ends of the projection 54a and the recess 55a, respectively.

With such a configuration, as shown in FIG. 7B, when the longitudinal ends 540a1 and 550a1 of the protruding portion 540a and the concave portion 550a are formed in parallel to the direction in which the developing roller 51 rotates, respectively. In comparison, it is possible to reduce the problem that the developer moving along with the rotation of the developing roller 51 stays at both ends in the longitudinal direction (the inclined portions 54a1 and 55a1). That is, in the case where the inclined portions 54a1 and 55a1 are formed as shown in FIG. 7A, even if the groove is formed with a gap in that portion as compared with the one shown in FIG. Since the time in which the developer carried by the roller 51 and moving is in contact with the groove can be shortened, the developer hardly enters the groove. Therefore, the disadvantage that the developer entering the groove is fixed and narrows the downstream casing gap G can be reliably reduced.
In the present embodiment, the inclination angle θ of the inclined portions 54a1 and 55a1 is set to about 60 degrees.

In the present embodiment, the second casing member 55 is fixed to the first casing member 54 without using screw fastening in the vicinity of the portion where the downstream casing gap G is formed.
On the other hand, as shown in FIG. 8, in the vicinity of the portion where the upstream casing gap is formed (the portion surrounded by a broken line S ′ in FIG. 8), the second casing member 54 and the second casing member 54 are separated from each other. The casing member 55 can be fixed without using screw fastening. That is, the second casing member 55 faces the outer peripheral surface of the developing roller 51 with a gap on at least one of the downstream side and the upstream side in the rotation direction of the development roller 51 with respect to the development area. As long as it is formed so as to cover a part of the outer peripheral surface of the developing roller 51, at least one of the downstream side in the rotational direction and the upstream side in the rotational direction of the developing roller 51 with respect to the developing area, The first casing member 54 can be configured so as to be fitted and positioned and fixed without being fastened.
Specifically, in the example of FIG. 8, the vicinity of the portion where the downstream casing gap G is formed (the portion surrounded by the broken line S in FIG. 8 and a portion configured in the same manner as that of the present embodiment). In the same manner as in the present embodiment, in the vicinity of the portion where the upstream-side casing gap is formed (the portion surrounded by the broken line S ′ in FIG. The second casing member 55 is fixed to the first casing member 54 without providing a portion or the like and using screw fastening.
In such a case, the operation of adjusting the position of the second casing member 55 with respect to the first casing member 54 in order to form a desired upstream casing gap becomes unnecessary. The assemblability of the second casing member 55 with respect to 54 is relatively good, and it is difficult for the operator to vary the upstream casing gap, and a desired upstream casing gap is formed stably and with high precision. Such a configuration is particularly useful when the accuracy of the upstream casing gap greatly affects quality such as toner scattering and toner adhesion.

As described above, in the developing device 5 according to the present embodiment, the second casing member 55 is provided on at least one of the downstream side and the upstream side in the rotation direction of the developing roller 51 with respect to the development area. The first casing member 54 is fitted and positioned with respect to the first casing member 54 and is fixed without being fastened.
As a result, the second casing member 55 that covers a part of the outer peripheral surface of the developing roller 51 is fixed to the first casing member 54 that holds the developing roller 51, so that the developing roller 51 and the second casing member 55 When the casing gap G is formed between the first casing member 54 and the first casing member 54, the assemblability of the second casing member 55 is relatively good. It can be formed accurately and accurately.

In the present embodiment, the process cartridge 6 is integrated with the photosensitive drum 1 (image carrier), the charging unit 4, the developing device 5, the cleaning unit 2, and the recycled toner paths 3, 29. However, the developing device 5 may be configured as a single unit that is detachable (replaceable) from the image forming apparatus main body without using the developing device 5 as a constituent member of the process cartridge 6.
The “process cartridge” includes a charging unit that charges the image carrier, a developing device (developing unit) that develops a latent image formed on the image carrier, and a cleaning unit (a cleaning unit that cleans the image carrier). And at least one of the cleaning devices) and the image carrier are defined as a unit that is integrated and detachably installed in the image forming apparatus main body.

Further, in the present embodiment, both the downstream side and the upstream side in the rotation direction of the developing roller 51 with respect to the developing area are opposed to the outer peripheral surface of the developing roller 51 with a gap. The present invention is applied to the developing device 5 in which the formed second casing member 55 is installed. On the other hand, on either one of the downstream side and the upstream side in the rotational direction of the developing roller with respect to the developing region, the developing roller is formed to face the outer peripheral surface of the developing roller with a gap. The present invention can be applied to a developing device provided with a second casing member.
Further, the present invention is applied to the developing device 5 in which the first casing member 54 and the second casing member 55 are arranged in the vertical direction. On the other hand, the present invention is also applicable to a developing device in which the first casing member and the second casing member are arranged in a direction different from the vertical direction (for example, a horizontal direction). Can be applied.
In such cases, substantially the same effects as those of the present embodiment can be obtained.

In the present embodiment, the present invention is applied to a developing device 5 using a two-component developer including a toner and a carrier. On the other hand, the present invention can be applied to a developing device using a one-component developer including only toner (including external additives and the like).
In the present embodiment, the present invention is applied to the developing device 5 in which the untransferred toner collected by the cleaning unit 2 is supplied as recycled toner. Naturally, the present invention can also be applied to a developing device that is not supplied as.
In such cases, substantially the same effects as those of the present embodiment can be obtained.

  It is to be noted that the present invention is not limited to the present embodiment, and it is apparent that the present embodiment can be appropriately modified within the scope of the technical idea of the present invention, in addition to the suggestions in the present embodiment. is there. Further, the number, position, shape, and the like of the constituent members are not limited to the present embodiment, but can be set to a number, position, shape, and the like suitable for carrying out the present invention.

1 photosensitive drum (image carrier),
5 developing device (developing section),
6 process cartridge (imaging unit)
51 developing roller (developer carrier),
52 Doctor blade (developer regulating member)
53 transport screw (transport member),
54 first casing member (lower case),
54a protrusion,
54a1 slope,
54b boss part,
54c wall,
55 second casing member (upper case),
55a recess,
55a1 slope,
55b hole,
55c facing surface,
56 inlet seal,
G casing gap (downstream casing gap),
X Opening.

Japanese Patent No. 4535852

Claims (7)

A developing device for developing a latent image formed on a surface of an image carrier that travels in a predetermined direction,
A developing roller that forms a developing region facing the image carrier, carries a developer, and rotates in a predetermined direction;
A first casing member that rotatably holds the developing roller;
An outer peripheral surface of the developing roller such that at least one of a downstream side in the rotational direction and an upstream side in the rotational direction of the developing roller with respect to the developing region is opposed to the outer peripheral surface of the developing roller with a gap therebetween; A second casing member covering a portion of the second casing member;
With
The first casing member has a protrusion formed to project toward the second casing member,
Said second casing member, the while fitting the projecting portion, provided with a recess in which the is the second casing member I abutting the protrusion is restricted so as not to displace the side of the developing roller,
At both ends in the longitudinal direction corresponding to the rotation axis direction of the developing roller of the projecting portion and the concave portion, an inclined portion inclined in a predetermined direction with respect to the direction in which the developing roller rotates is formed ,
A developing device provided so that a boundary between the protrusion and the recess is exposed at a position where the developer carried by the developing roller contacts, and the inclined portion is provided at the exposed boundary. .   The developing device according to claim 1, wherein the projecting portion and the concave portion are formed at positions facing the developing roller. The projecting portion is formed in a substantially trapezoidal shape such that a direction projecting toward the second casing member is a height direction,
The developing device according to claim 1, wherein the concave portion is formed in a substantially trapezoidal shape so as to match a shape of the projecting portion.   The said 1st casing member was equipped with the wall part which opposes the said 2nd casing member over the said longitudinal direction, and regulates so that the said 2nd casing member may not be displaced to the side away from the said developing roller. The developing device according to claim 1. The first casing member is formed so as to cover a lower part of the developing device installed in the image forming apparatus main body,
The second casing member has an opening that exposes a part of the developing roller at a position above the developing device in a state where the second casing member is installed in the image forming apparatus main body, and is installed in the image forming apparatus main body. The developing device is formed so as to cover the upper part of the developing device in a state where the developing device is moved upward and downward with respect to the first casing member. The developing device according to any one of claims 1 to 4, wherein the developing device is positioned and fitted to the first casing member on a downstream side and is fixed by non-fastening. A process cartridge detachably mounted to the image forming apparatus main body,
6. A process cartridge comprising the developing device according to claim 1 and the image carrier integrally.   An image forming apparatus comprising: the developing device according to claim 1; and the image carrier.

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