JP6651873B2 - Developing device, process cartridge and image forming device - Google Patents

Description

  The present invention relates to a developing device, a process cartridge, and an image forming apparatus.

An image forming apparatus using an electrophotographic method may include a developing device that uses a two-component developer containing a toner and a carrier in addition to a one-component developer containing only a toner.
A developing device using a two-component developer, for example, uses a developer carrier having a plurality of built-in magnetic poles, makes a magnetic brush of the developer stand on its surface, and transfers the toner in the magnetic brush to the latent image carrier. The visible image processing is performed by transferring the image to the electrostatic latent image formed in the image.

The magnetic brush formed on the surface of the developer carrier may include uncharged toner that does not have a charge amount enough to be electrostatically attached to the carrier. It may float and contaminate peripheral devices and recording media.
As a configuration for collecting the floating uncharged toner, a configuration in which the uncharged toner is taken into the developing tank using a suction airflow generated when the magnetic brush moves along the inner wall of the developing tank (for example, [Patent Document 1] See).

  However, in the developing device, the internal pressure is likely to increase due to the suction airflow described above and the rotation of a blade such as a transport screw incorporated as a transport member. If a blowout occurs outside the developing device due to the increased internal pressure, not only the uncharged toner but also the toner contained in the developing device may leak out of the developing device and contaminate peripheral devices and a recording medium.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a developing device that prevents toner from leaking out of the developing device and prevents contamination of peripheral devices and a recording medium outside the developing device due to the leaked toner.

In order to achieve this object, the present invention comprises a rotatable developer carrier in which developer is raised on the surface by a magnetic force, and a floating toner flows into a developing tank by a peripheral airflow generated when the developer carrier rotates. In the developing device to be collected, the facing distance between the inner wall of the developing tank and the surface of the developer carrying member is longer than the facing distance of the magnetized region where the developer stands in the longitudinal direction of the developer carrying member. the deposition it is rather narrow outer side of the counter interval magnetized region, the opposing distance of the outside of the magnetization region in the longitudinal direction, the provided on the inner wall of the developing tank facing the developing agent carrier spacing In the developing device narrowed by the adjusting member .

  According to the present invention, it is possible to prevent toner from leaking out of the developing device and prevent contamination of peripheral devices and a recording medium outside the developing device due to the leaked toner.

FIG. 1 is a schematic diagram illustrating an example of a developing device according to the present invention. FIG. 2 is a sectional view illustrating details of a developing device illustrated in FIG. 1. FIG. 2 is a schematic diagram for explaining an airflow generated in the developing device illustrated in FIG. 1. FIG. 2 is a diagram for explaining each region in a longitudinal direction of a developer carrier provided in the developing device illustrated in FIG. 1. FIG. 3 is a partially enlarged view of the configuration shown in FIG. 2. FIG. 6 is a perspective view for describing an arrangement of a sealing member corresponding to an arrangement of a gap adjusting member shown in FIG. 5. FIG. 7 is a perspective view illustrating an installation state of a gap adjusting member and a sealing member illustrated in FIG. 6. FIG. 8 is a diagram illustrating a state in which the interval adjusting member and the sealing member illustrated in FIG. 7 are installed, as viewed from the latent image carrier side. FIG. 2 is a schematic diagram illustrating an example of an image forming apparatus using the developing device illustrated in FIG. 1. FIG. 9 is a perspective view for explaining a problem of a conventional process cartridge.

The developing device 1 according to the present invention shown in FIGS. 1 and 2 is collectively equipped and accommodated in a housing of a process cartridge 20 together with a photosensitive drum 10 as a latent image carrier. The process cartridge 20 includes a developing device 1, a photosensitive drum 10, a charging device 11 disposed around the photosensitive drum 10, and a cleaning device 12, and is used for an image forming process.
FIG. 9 shows an image forming apparatus 100 according to the present invention. The process cartridge 20 is provided detachably with respect to the main body of the image forming apparatus 100. As a result, when the members provided therein reach the end of their life, the process cartridge 20 is taken out of the main body of the image forming apparatus 100 as the process cartridge 20, and the members whose life has expired are replaced with new ones. By being able to exchange, the operability of the exchanger is improved.

As shown in FIGS. 1 and 9, the photosensitive drum 10 is uniformly charged by the charging device 11 and is written by the writing device (for convenience, the writing light is indicated by the symbol L) in the process of rotating in the direction of the arrow in the drawing. Latent image formation and visible image processing of the latent image by the developing device 1 are respectively performed.
A visible image formed on the photosensitive drum 10, that is, a so-called toner image, is transferred onto a recording medium S such as recording paper by a transfer device 13 shown in FIGS. In both figures, a device which is disposed adjacent to the transfer device 13 and is indicated by reference numeral 14 is a charger for electrostatically separating the recording medium S from the photosensitive drum 10.

  Note that the image forming apparatus 100 shown in FIG. 9 is a direct transfer type in which the toner image on the photosensitive drum 10 is directly transferred to the recording medium S. However, in the indirect transfer type image forming apparatus, the toner image is The image is transferred from the latent image carrier to an intermediate transfer member, and further transferred to a recording medium. The intermediate transfer member is a member used when, for example, superimposing and transferring toner images of a plurality of colors in an indirect transfer type image forming apparatus such as a color image forming apparatus, and collectively transfers the superimposed images to a recording medium.

The untransferred toner and residual charges remaining on the photosensitive drum 10 after the transfer are removed by the cleaning device 12.
The cleaning device 12 includes a cleaning blade 12A that can collect untransferred toner from the photosensitive drum 10 and a collection screw 12B that is disposed in a collection path that conveys the collected toner toward the developing device 1. If uncollected toner or paper dust is present in such a degree that the collected toner cannot be used for development, the collected toner may be conveyed to a waste tank.

The developing device 1 includes a rotatable developer carrier 2 that is disposed to face the photoconductor drum 10 and supplies toner in the developer that has been spiked on the surface by magnetic force to the photoconductor drum 10. It is provided inside the housing 1A. The specific internal configuration of the developer carrier 2 is the same as that shown in, for example, FIG.
As shown in FIG. 2, the housing 1 </ b> A has a pair of spaces partitioned in a horizontal direction by a partition wall 1 </ b> A <b> 1 provided below the developer carrier 2. Among the pair of spaces, a developer supply screw 3 is provided in a space directly below the developer carrier 2, and a developer recovery screw 4 is provided in a space horizontally adjacent to the space in which the developer supply screw 3 is disposed. , Respectively.

  The pair of spaces are provided when a pair of screws having different functions are arranged, but depending on the type of the developing tank, the space is not limited to the horizontal direction, and may be partitioned in an oblique direction or a vertical direction. .

Of the developer supply screw 3 and the developer recovery screw 4 having different functions, the developer supply screw 3 is a member capable of supplying and transporting the developer in opposition to the developer carrier 2. The collection screw 4 is a member that can transport the developer.
The developer carrier 2, the developer supply screw 3, and the developer recovery screw 4 are provided such that a direction perpendicular to the paper surface of FIG. 2 is an axial direction corresponding to a longitudinal direction.

The partition wall 1A1 has notches at positions corresponding to both longitudinal ends of the developer supply screw 3 and the developer recovery screw 4, and a pair of spaces communicate with each other at the positions of the notches.
The developer supply screw 3 and the developer recovery screw 4 have spiral blades formed on the outer periphery of the shaft. When the forming directions of the spiral blades are the same, the developer supply screw 3 and the developer collecting screw 4 are set in directions in which the rotating directions are opposite to each other, and the forming directions of the spiral blades are opposite to each other. In some cases, the rotation direction is set to the same direction. In the present embodiment, the rotation directions are set to the same direction.
As a result, in the housing 1A, the developer is conveyed in opposite directions along the axial direction in the pair of partitioned spaces, and the developer enters the other space from each notch of the partition wall 1A1. The developer circulates.

  In the developing device 1, when the developing device 1 is operated, that is, when the developer carrier 2 is rotated, the surface of the developer carrier 2 passes through a developing region where the developer carrier 2 and the photosensitive drum 10 face each other. The standing magnetic brush moves along the inner surface of the housing 1A. Due to the peripheral airflow generated at this time, the floating developer which is likely to float due to insufficient charging between the developer carrier 2 and the photosensitive drum 10, particularly on the downstream side of the developing area in the rotation direction of the developer carrier 2. The toner, in particular, the uncharged toner is collected in the housing 1A. The peripheral air current has a function of not only collecting the uncharged toner outside the developing device 1 but also preventing or suppressing the toner accumulated in the developing device 1 from leaking out of the developing device 1 carelessly. .

The peripheral airflow for collecting the uncharged toner in the housing 1A is generated as follows. As shown in FIG. 3, the surrounding air is suctioned by the air generated on the upstream side in the direction in which the magnetic brush of the developer T rising on the surface of the developer carrier 2 moves along the inner wall 1A2 of the housing 1A. The inflow creates a surrounding airflow. In FIG. 3, a state in which the surrounding air flows is indicated by a broken-line arrow, and the broken-line arrow indicates the surrounding airflow Aa generated by the intake of the surrounding air.
When the uncharged toner rides on the peripheral airflow Aa flowing toward the inside of the housing 1A, the uncharged toner is sucked into the housing 1A, and the leakage of the developer to the outside of the developing device 1 is prevented or suppressed. This prevents or suppresses contamination of peripheral devices and recording media caused by the above.

The peripheral airflow Aa shown in FIG. 3 is located outside the magnetized area P1 (see FIG. 4) in the longitudinal direction X of the developer carrier 2 and the magnetized area P1. The strength is different between the rotary support portion having the rotary support shaft of the above. In FIG. 4, reference symbol X indicates a longitudinal direction coinciding with the axial direction of the developer carrier 2. The longitudinal direction X coincides with the direction perpendicular to the paper surface of FIGS. 1 to 3, 5, and 9, and coincides with the longitudinal direction of the developer supply screw 3 and the developer collection screw 4. In FIG. 5, the longitudinal direction X is indicated by a solid black double circle.
In the magnetized region P1 of the developer carrier 2 in the longitudinal direction X, the peripheral airflow flowing into the housing 1A according to the movement of the magnetic brush due to the formation of the magnetic brush, that is, the suction airflow Ab shown in FIG. The air volume is large and the strength (wind pressure) is strong.
On the other hand, in the rotation support portion at the end, the outside air is hardly taken in by the magnetic brush, and when the outside air taken in the magnetized region P1 flows in, the accumulated air is pushed out of the housing 1A. When the air accumulated in the magnetized area P1 in the housing 1A is pushed out to the rotation support portion side, as shown in FIG. 10, there is a possibility of a blown airflow B in which air is blown out of the housing 1A outside the magnetized area P1. Will exist.

In order to prevent air from being blown off at the axial end of the developer carrier 2, the developing device 1 of the present embodiment has an air hole communicating the space at the end in the longitudinal direction X with the outside. It is provided on the housing 1 </ b> A above the recovery screw 4 (see FIG. 4). The air hole is provided with a filter for preventing uncharged toner from leaking outside through the air hole.
Generally, when a filter is provided, if the filter is clogged with time, the flow of air is suppressed. In the developing device 1, similarly to the case shown in FIG. 10, a force for blowing air to the outside of the developing device 1 from the end in the longitudinal direction X of the developer carrier 2, that is, outside the magnetized area P <b> 1. Can occur. When the air blows out of the developing device 1, the toner accumulated in the housing 1A blows out of the developing device 1, and the toner floating outside the developing device 1 is not collected.

In the developing device 1 of FIG. 4, in order to prevent or suppress the generation of an airflow that tends to blow out of the developing device 1 from a region outside the magnetized region P1 in the longitudinal direction X (a region indicated by a symbol P2 in FIG. 4). The following configuration is employed. That is, a configuration is employed in which a reduction in the air intake effect in the region P2 is prevented or suppressed.
Specifically, as shown in FIG. 5, portions of the housing 1 </ b> A facing the developer carrier 2 correspond to both ends in the longitudinal direction X of the developer carrier 2, that is, regions P <b> 2, respectively. The configuration in which the interval adjusting member 5 is provided is employed.
The surface of the gap adjusting member 5 facing the developer carrier 2 is the position of the housing 1A where the space adjusting member 5 is not provided, that is, the surface of the housing 1A facing the developer carrier 2 in the magnetized area P1. An inner wall 1A2 is formed.

Due to the thickness T1 of the gap adjusting member 5, the facing gap G1 between the surface of the developer carrier 2 and the inner wall 1A2 in the area P2 formed by the gap adjusting member 5 is determined by the magnetization of the surface of the developer carrier 2 and the housing 1A. The gap P2 is smaller than the interval G2 between the area P1 and the inner wall 1A2. Specifically, as shown in FIG. 5, G1 <G2 and G2−G1 = T1, and the area P2 shown in FIG. 4 is a narrow gap area.
The facing distance G2 is set to a distance at which a minimum necessary suction airflow intensity is obtained to prevent or suppress the toner inside the housing 1A from leaking out of the developing device 1. The facing gap G1 is set to be greater than or equal to the facing gap G2 so as to obtain the strength of the suction airflow that prevents or suppresses the leakage of the toner inside the housing 1A to the outside of the developing device 1.

In the area P2, unlike the magnetized area P1, air is less likely to be sucked by the movement of the magnetic brush. However, due to the relationship of G1 <G2, the air pushed out of the magnetized area P1 in the housing 1A is prevented or suppressed from blowing out of the developing device 1 from the area P2.
In the area P2, the strength of air suction by the movement of the magnetic brush is weaker than in the magnetized area P1, so that the uncharged toner that has entered the housing 1A easily leaks to the outside again. However, by setting the relationship of G1 <G2 and intensifying the suction airflow (wind speed) due to the rotation of the developer carrier 2 itself in the region P2, a state in which the toner in the housing 1A is hard to leak out of the developing device 1 is obtained. .

More specifically, since the opposing interval G1 is narrower than the opposing interval G2 due to the thickness T1 of the interval adjusting member 5, the opposing interval G1 is set in the longitudinal direction X in the area P2 which is a narrow gap area. The airflow speed (wind speed) increases. Therefore, the suction airflow from the outside of the developing device 1 into the housing 1A due to the rotation of the developer carrier 2 itself is locally increased in the region P2, and the toner in the housing 1A including the uncharged toner once sucked into the housing 1A is removed. Maintain a state where leakage is prevented or suppressed.
As shown in FIG. 4, in the longitudinal direction X, the magnetized area P1 includes the paper passing area P0 and extends to the outside of the paper passing area P0. Therefore, in the paper passing area P0, the suction airflow by the magnetic brush is reliably obtained, and the blowing of the toner to the outside of the developing device 1 is highly suppressed or prevented. Therefore, contamination of the recording medium S due to spraying of the toner on the recording medium S passing through the paper passing area P0 to the outside of the developing device 1 is highly suppressed or prevented.

In the magnetized region P1, the suction airflow is reliably generated by using the magnetic brush. Therefore, unlike the region P2, it is not necessary to increase the airflow by narrowing the facing gap G2. For this reason, the facing distance G2 is set to be larger than the facing distance G1 to such an extent that suction of uncharged toner in the housing 1A and blowing of toner out of the developing device 1 are prevented or suppressed (FIG. 4, FIG. G1 <G2 shown in FIG. 5). Therefore, the pressure of the suction airflow in the magnetized region P1 is weaker than that in the region P2, and the pressure of the air pushed from the magnetized region P1 to the region P2 in the housing 1A also becomes lower. Further, the total amount of air per hour sucked into the housing 1A over the magnetization region P1 and the region P2 is also suppressed. Therefore, the pressure and volume of the air sucked into the housing 1A are suppressed in the entire area in the longitudinal direction X, and the clogging of the filter is suppressed.
As described above, in FIG. 4, the magnetizing region P1 is set to correspond to the setting range of the facing distance G2 shown in FIG. 5, and the region P2 is set to correspond to the setting range of the facing distance G1 shown in FIG.

  The gap adjusting member 5 increases the strength of the suction airflow by narrowing the facing gap G1 as the thickness T1 increases, but the cross-sectional area of the suction airflow decreases. If the cross-sectional area of the suction airflow is small, uncharged toner that cannot enter the housing 1A is generated depending on the amount of uncharged toner that is recovered by multiplying the suction airflow. The uncharged toner that cannot enter the housing 1 </ b> A accumulates outside the developing device 1 around the gap adjusting member 5, and appears as if overflowing from the facing gap G <b> 1 of the gap adjusting member 5.

Therefore, the gap adjusting member 5 is formed of an elastic member that can be elastically deformed in accordance with the pressing force when the uncharged toner passes through the facing gap G1 within a relationship of G1 <G2. The elastic deformation is larger than that of the housing 1A when passing through the facing gap G2.
The gap adjusting member 5 is made of urethane foam, is elastically deformable in accordance with the force pressed by the contacted uncharged toner or developer, and faces when the uncharged toner flows in according to the toner particle size. The interval G1 is enlarged.
The elasticity and hardness of the gap adjusting member 5 may be determined, for example, by experimentation to provide the velocity of the suction airflow determined from the facing gap G1 and the flexibility to cause deformation by passing a predetermined amount of toner due to collision force when the collision occurs. It is desirable to use and set.
The elasticity and hardness of the gap adjusting member 5 can be changed depending on the degree of foaming of the urethane foam.

  When an elastic member is used for the interval adjusting member 5, the opposing interval G1 is widened by the pressing force of the uncharged toner sucked into the housing 1A by multiplying the suction airflow in the area P2, so that the uncharged toner can pass. . As a result, in combination with the local enhancement of the suction airflow in the region P2, the inhibition of the incorporation of the uncharged toner into the housing 1A is suppressed or prevented even when G1 <G2.

The space adjusting member 5 has a surface on which the inner wall 1A2 is formed so as to suppress or prevent the movement of the uncharged toner or developer taken in the housing 1A from being hindered by the contact with the space adjusting member 5. Surface roughness is set. That is, the surface of the gap adjusting member 5 on which the inner wall 1A2 is formed is set to have such a surface roughness that smoothness of the uncharged toner or the developer can be obtained. The surface roughness is set so that smoothness can be obtained from the housing 1A when passing through the gap G2.
The surface roughness of the gap adjusting member 5 is set with the intention that the movement of the uncharged toner passing through the facing gap G1 is hardly hindered, and the smaller the surface roughness, the higher the smoothness. The rubbing resistance between the uncharged toner and the gap adjusting member 5 is reduced. It should be noted that “sliding” means sliding, and “sliding resistance” means resistance generated when rubbing while sliding.

With such setting of the surface roughness, the uncharged toner and the developer that have come into contact with the surface of the gap adjusting member 5 forming the inner wall 1A2 can easily slide. Therefore, even if the contact area between the gap adjusting member 5 and the uncharged toner increases due to the elastic deformation of the gap adjusting member 5, the resistance to the flow of the uncharged toner into the housing 1A is reduced. Therefore, the setting of the surface roughness and the elastic deformation of the gap adjusting member 5 improve the ability to take in the uncharged toner into the housing 1A. Further, since the sliding resistance of the uncharged toner is reduced and the uncharged toner slides smoothly, the deterioration of the surface of the interval adjusting member 5 forming the inner wall 1A2 due to abrasion or the like is suppressed.
In setting the surface roughness of the surface forming the inner wall 1A2 of the gap adjusting member 5, not only the sliding of the uncharged toner is regarded as important, but also other factors, for example, the fluid dynamics of the airflow contacting the surface. It is also possible to determine in consideration of the characteristic. The setting of the facing gap G1 may be performed according to the shape of the housing 1A itself. However, if the facing gap G1 is set using the spacing adjusting member 5 which is a separate member from the housing 1A, the elasticity and / or surface roughness and There is an advantage that the facing distance G1 can be set relatively easily.

As shown in FIGS. 5 to 7, the developing device 1 includes a sealing member 6 that is arranged corresponding to the region P2 and blocks air that may blow out from the region P2 to the outside of the housing 1A that forms the developing tank. Have.
The sealing member 6 is formed of a plate made of PET (polyethylene terephthalate) having flexural rigidity. As shown in FIG. 6, the sealing member 6 includes a pair of end sealing portions 6 </ b> A located on both sides in the longitudinal direction X of the developer carrier 2, and one portion connecting the end sealing portions 6 </ b> A to each other. And a longitudinal sealing portion 6B made of
As shown in FIG. 8, the end sealing portion 6 </ b> A is disposed at a position where a pair of interval adjusting members 5 are provided in the longitudinal direction X of the developer carrier 2. That is, as shown in FIG. 5, the end sealing portion 6 </ b> A covers the outside of the developer carrier 2, specifically, the upper portion of the developer carrier 2 at a position coinciding with the region P <b> 2. Are located.
The end sealing portion 6A is positioned such that the distal end of the end sealing portion 6A on the interval adjusting member 5 side is located above the interval adjusting member 5 so as not to obstruct the flow of the suction airflow Ab (see FIG. 7) in the region P2. They are arranged so as to have an interval (see FIGS. 5 and 7). The end sealing portion 6 </ b> A functions as a sealing portion for sealing the blowing of the air to the outside of the developing device 1 when the air to be blown out from the inside of the developing device 1 collides.
As shown in FIG. 5, the longitudinal sealing portion 6 </ b> B is used as a portion that shields a part of the peripheral surface of the developer carrier 2 from the photosensitive drum 10. As a result, the longitudinal sealing portion 6B seals the flow of air from the developing device 1 side to the photosensitive drum 10 and prevents toner floating from the developing device 1 side from adhering to the photosensitive drum 10. prevent.

  As shown in FIG. 9, the image forming apparatus 100 accommodates the developing device 1 having the above-described configuration in an image forming section substantially at the center in the vertical direction inside the housing 100 </ b> A. 2 is provided. The image forming apparatus 100 includes a single process cartridge 20 so that a monochrome image can be formed. The image forming apparatus 100 includes a paper feeder 101 below the process cartridge 20 and a document scanning unit 102 above the process cartridge 20.

The paper feeding device 101 includes a cassette 101A on which the recording medium S can be loaded, a feeding roller 101B, a feeding roller 101C, and a registration roller 101D disposed in front of the transfer position.
The document scanning unit 102 includes a movable mirror 102B that optically scans a document mounted on a document table 102A, a condenser lens 102C, and a reading element 102D.

  The toner image formed on the photosensitive drum 10 in the process cartridge 20 is transferred onto a recording medium S fed from a paper feeding device 101. After the toner image is transferred onto the recording medium S, the toner image is fixed by the fixing device 103, and then the recording medium S is discharged to a discharge tray 100A1 provided in the housing 100A.

  Although the image forming apparatus according to the present invention is intended for forming a monochrome image, a plurality of process cartridges having the developing device 1 according to the present invention may be provided according to the number of image forming colors. In this case, the toner images formed in the respective process cartridges are sequentially transferred to an intermediate transfer body to form a superimposed image, and then are collectively transferred to a recording medium.

As described above, the preferred embodiments of the present invention have been described. However, the present invention is not limited to such specific embodiments, and unless otherwise specified in the above description, the present invention will be described in the claims. Various modifications and changes are possible within the spirit of the invention.
For example, as the narrow interval region, not only outside the magnetized region but also outside including the end of the magnetized region, the suction airflow may be strengthened in the region where the influence of the magnetic brush becomes unstable. It is possible. Further, as a method of increasing the suction airflow, it is also possible to use a supply of suction air for promoting suction of the uncharged toner into the developing tank on the premise that a narrow interval is set. Further, the interval adjusting member may not be an elastic member, and when the interval adjusting member is an elastic member, the material is not limited to urethane foam, and may be, for example, a plate-shaped member that can be flexibly deformed.
The effects described in the embodiments of the present invention merely enumerate the most preferable effects resulting from the present invention, and the effects of the present invention are limited to those described in the embodiments of the present invention. is not.

1 Developing device 1A Housing (Example of developing tank)
1A2 Inner wall of housing (example of inner wall of developing tank)
2 developer carrier 5 interval adjusting member 6 sealing member 10 photosensitive drum (an example of a latent image carrier)
Reference Signs List 20 Process cartridge 100 Image forming apparatus Aa Peripheral airflow Ab Suction airflow B Blowout airflow G1 Opposing interval outside magnetized area G2 Opposing interval in magnetized area P0 Paper passing area P1 Magnetized area P2 Area outside magnetized area X Longitudinal direction of developer carrier

JP 2004-252193 A

Claims (8)

In a developing device, the developer is provided with a rotatable developer carrier on which the developer is raised on the surface by a magnetic force, and a floating toner is collected in a developing tank by a peripheral airflow generated when the developer carrier is rotated.
The facing distance between the inner wall of the developing tank and the surface of the developer carrier is outside the magnetized area in the longitudinal direction of the developer carrier than the facing distance of the magnetized area where the developer stands. person of the opposite interval of rather narrow,
The developing device , wherein the facing space outside the magnetized region in the longitudinal direction is narrowed by a space adjusting member provided on the inner wall of the developing tank facing the developer carrier .   The developing device according to claim 1, wherein the magnetized area in the longitudinal direction is wider than a paper passing area. The developing device according to claim 1 , wherein the gap adjusting member is an elastic member that elastically deforms . Any one of the preceding claims wherein the developer carrying member and the surface facing in the distance adjusting member, wherein said a inner wall smoothness surface roughness obtained than the developing tank the developing device according to. The developing tank is provided with a sealing member arranged to face the surface of the developer carrier over the outside of the magnetized region in the longitudinal direction,
The sealing member has, at a position corresponding to the installation position of the gap adjusting member in the longitudinal direction, an end sealing portion having a longer length in a direction orthogonal to the longitudinal direction than a portion corresponding to the magnetized region. an apparatus according to any one of claims 1 to 4, wherein a. The developing tank is provided with an opening that exposes a part of the surface of the developer carrier over the outside of the magnetized region in the longitudinal direction,
The end sealing portion faces the surface of the developer carrier that is exposed from the opening, and is disposed so as to cover a part of the surface of the developer carrier,
A tip of the end sealing portion along a rotation direction of the developer carrier on a side facing the surface of the developer carrier is along the rotation direction on a side near the opening of the gap adjusting member. The developing device according to claim 5 , wherein the developing device is arranged at a distance from the front end. A process cartridge capable of housing the developing device according to claim 1,
A process cartridge comprising at least the developing device and a latent image carrier . An image forming apparatus comprising the process cartridge according to claim 7, wherein:
An image forming apparatus , wherein a plurality of the process cartridges are provided in accordance with the number of image forming colors .

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