JPH0876668A - Process cartridge and image forming apparatus - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To provide a process cartridge and an image forming apparatus capable of reliably preventing developer leakage even when subjected to thermal change, impact, or the like. In a process cartridge detachable from an image forming apparatus main body, an image carrier, at least one process unit acting on the image carrier, and a gap in which a first wall surface and a second wall surface made of different materials face each other. A flexible sheet member for sealing a portion, and
It is characterized in that the wall surface and the second wall surface are brought into contact with each other, and at least one of the contacting surfaces is adhered to the wall surface.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a process cartridge and an image forming apparatus for forming an image using a developer.

[0002]

2. Description of the Related Art In an image forming apparatus such as a printer, a latent image is formed by selectively exposing an image carrier uniformly charged by a charger, and the latent image is developed by a developer by a developer. At the same time as forming an image, the image formed by the developer is transferred to a recording medium to record an image. Then, the developer remaining on the image carrier after the image transfer is removed by a cleaning blade and stored in the waste toner reservoir, and the next development is performed by the image carrier having a clean surface.

In recent years, the image carrier, the charging device, the developing device, the cleaning unit and the like have been integrally formed into a cartridge so that the user can mount the cartridge in the apparatus main body to replenish the developer. It has been put into practical use that the parts of the image bearing member that have reached the end of their life can be replaced and the maintenance is easy.

In such an image forming apparatus or process cartridge, the developer stored in the cleaning container has a very small particle size of several μm, and it is necessary to prevent the developer from leaking from the container. . At this time, a cleaning container made of a synthetic resin and a container lid made of the same material can be welded together to prevent the developer from leaking between the two. However, for example, in the cleaning means, as shown in FIG.
Although 50 is made of synthetic resin, since the supporting member 52 that supports the squeeze sheet 51 is made of metal such as sheet metal, they cannot be welded to each other, and even if they are attempted to be bonded, the container 50 and the supporting member Since the coefficient of thermal expansion of 52 is different, the adhesive is peeled off due to the difference in thermal deformation.

Therefore, conventionally, as shown in FIG. 9, a magnet sheet 53 is sandwiched between the two so that the magnetic developer attempting to leak from the gap is adsorbed by the magnet sheet 53, or the magnet sheet 53 Instead, a malt plane is interposed between the two, and the container 50 and the supporting member are provided.
The developer was kept from leaking between 52.

[0006]

However, in the structure in which the magnet sheet 53 is sandwiched, the sheet is
Since 53 is not adhered to the contact surface, the developer may leak against the magnetic force when the cleaning container receives a strong impact (for example, in the case of a process cartridge, it drops).

In addition, in the structure in which the malt plane is interposed, since the malt plane is compressed and interposed between the cleaning container 50 and the supporting member 52, the repulsive force loads the metallic supporting member 52. Therefore, the supporting member 52 may be bent and may be bent.

As a result, there is a possibility that the developer may leak from the cleaning container 50 to stain the surroundings, or the developer may leak onto the recording medium to stain an image.

The present invention is to solve the above-mentioned conventional problems, and an object of the present invention is to provide a process cartridge and an image capable of surely preventing developer leakage even when a thermal change or impact is applied. It is intended to provide a forming device.

[0010]

A typical configuration according to the present invention for achieving the above object is to provide a process cartridge detachable from an image forming apparatus main body with an image carrier.
The flexible sheet member includes at least one process unit that acts on the image carrier, and a flexible sheet member that seals a gap portion where the first wall surface and the second wall surface of different materials face each other. Is brought into contact with the first wall surface and the second wall surface, and at least one of the abutting surfaces is bonded to the wall surface.

In an image forming apparatus for forming an image on a recording medium, an image carrier, developing means for forming a developed image on the image carrier, and transfer for transferring the developed image to the recording medium. Means and a cleaning means for removing the developer remaining on the image carrier after the transfer of the developed image,
A transporting means for transporting the recording medium, and a first different material
A flexible sheet member for sealing a gap portion where the wall surface and the second wall surface face each other, and the flexible sheet member is brought into contact with the first wall surface and the second wall surface, and at least the contact is made. One of the features is that one is bonded to the wall surface.

[0012]

In the above structure, since the sheet member is in contact with the gap between the first wall surface and the second wall surface, the developer does not leak from the gap portion.

Further, even if a thermal deformation deviation occurs between the first wall surface and the second wall surface, this deviation is absorbed by the flexible sheet member, and the developer is prevented from leaking from the gap between both wall surfaces. To do.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a process cartridge and an image forming apparatus according to the present invention will be specifically described with reference to the drawings.

[First Embodiment] A first embodiment will be described with reference to FIGS. 1 to 4. FIG. 1 is an explanatory view of the seal configuration of the cleaning container, FIG. 2 is an explanatory view of the configuration of the image forming apparatus in which the process cartridge is mounted, FIG. 3 is an explanatory view of the configuration of the process cartridge, and FIG. FIG.

As an order of description, the overall structure of the process cartridge and the image forming apparatus will be described first with reference to FIGS. 2 to 4, and then the sealing structure of the cleaning container will be described with reference to FIG.

{Overall Configuration} This image forming apparatus A is shown in FIG.
As shown in, the laser beam L based on the image information is irradiated from the optical system 1 to form an image of a developer (hereinafter referred to as “toner”) on the photosensitive drum which is an image carrier. Then, in synchronization with the formation of the toner image, the recording medium 2 is loaded into the cassette 3a.
From pickup roller 3b and registration roller pair 3c
In the image forming portion which is conveyed by the conveying unit 3 including the above, and which is formed into a cartridge as the process cartridge B, the toner image formed on the photosensitive drum is applied with voltage to the transfer roller 4 serving as the transfer unit to thereby form the recording medium 2. Then, the recording medium 2 is guided by the guide plate 3d and conveyed to the fixing unit 5.

The fixing means 5 comprises a fixing roller 5c having a driving roller 5a and a heater 5b built therein, and applies heat and pressure to the recording medium 2 passing therethrough to fix the transferred toner image. Then, the recording medium 2 is conveyed by the discharge roller pair 3e and discharged to the discharge section 6.

On the other hand, in the process cartridge B constituting the image forming section, as shown in FIGS. 2 and 3, the photosensitive drum 7 having a photosensitive layer is rotated, and the surface thereof is transferred to a charging roller 8 which is a charging means. Is uniformly charged by the application of the voltage, and the optical image from the optical system 1 is exposed to the photosensitive drum 7 through the exposure unit 9 to form a latent image, and the latent image is developed by the developing means 10. There is.

In the developing means 10, the toner in the toner reservoir 10a is fed by the toner feeding member 10b, the developing roller 10d containing the fixed magnet 10c is rotated, and the toner layer to which the triboelectric charge is applied by the developing blade 10e is formed. A toner image is formed on the surface of the developing roller 10d and transferred to the photosensitive drum 7 according to the latent image to form a toner image and visualize it.

Then, after a voltage having a polarity opposite to that of the toner image is applied to the transfer roller 4 to transfer the toner image to the recording medium 2, the cleaning means 11 removes the toner remaining on the photosensitive drum 7. I am configuring. That is, the cleaning blade 11a contacting the photoconductor drum 7 scrapes off the toner on the photoconductor drum 7 and stores it in the waste toner reservoir 11b. At this time, the squeeze sheet 11c is in weak contact with the photosensitive drum 7 so that the toner does not leak from the waste toner reservoir 11b.

The parts such as the photosensitive drum 7 are composed of a toner container 12a forming a toner reservoir 10a and a developing roller.
A developing frame body 12b for holding 10d and the like, a cleaning container 12c for providing the photosensitive drum 7, the charging roller 8 and the cleaning means 11 and a shutter member 12d for protecting the photosensitive drum 7 from exposure are combined. The cartridge is housed in a synthetic resin housing and formed into a cartridge, which is detachably attached to a cartridge attaching means provided in the apparatus main body 13.

The mounting of the cartridge B is performed by opening the front unit 14 of the apparatus main body 13 as shown in FIG. That is, a front unit 14 which can be opened and closed by a hinge 14a is attached to the front portion of the apparatus body 13, and when the front unit 14 is opened, a cartridge mounting means 15 is provided in the apparatus body 13.

The construction of the cartridge mounting means is shown in FIG.
As shown in, the drum pin 15 that pivotally supports the photosensitive drum 7
a, a guide portion 15b, and a click spring 15 having elasticity
c are provided on both sides of the cartridge B. On the other hand, a guide hole portion for guiding the guide portion 15b is provided on the device body 13 side.
A click recess 15e into which the 15d and the click spring 15c are inserted and a positioning portion 15f for positioning the photosensitive drum 7 are formed on both side surfaces of the cartridge mounting space. When the process cartridge B is attached to the apparatus main body 13, a drum gear (not shown) attached to the end of the photoconductor drum 7 meshes with the drive gear 15g of the apparatus main body 13 to transmit the drive to the photoconductor drum 7. Be seen.

The shutter member 12d is opened and closed centering around the shaft 12d1 by the attachment / detachment of the process cartridge B by an opening / closing mechanism (not shown). When the cartridge B is mounted in the image forming apparatus A, the shutter member 12d is opened and the cartridge B is imaged. It is configured to close when removed from the forming apparatus A.

{Seal Configuration of Cleaning Container} Next, the seal configuration of the cleaning container 12c will be described with reference to FIG. In the cleaning means 11 of the present embodiment, polyethylene terephthalate, which is a flexible sheet, is used as the scooping sheet 11c. In order to maintain the angle between the scooping sheet 11c and the photosensitive drum 7 stable, the scooping sheet 11c is made of sheet metal. Double-sided tape on the supporting member 11d
The support member 11d is attached by means of 16 and is attached to the cleaning container 12c. The cleaning container 12c is made of synthetic resin, and the supporting member 11d is made of metal. Since both of them are in the vicinity of the fixing means 5 which generates heat and have different coefficients of thermal expansion, they are peeled off even if they are directly bonded. There is a risk. Therefore, although the support member 11d is attached by screws or fitting, the surface of the support member 11d (first wall surface)
The toner may leak from the gap between the surface of the cleaning container 12c and the surface (second wall surface) of the cleaning container 12c. Therefore, in this embodiment, the flexible sheet member 17 is attached to the gap to prevent the toner leakage.

As the flexible sheet member 17, a sheet of polyethylene terephthalate having a thickness of about 50 μm, which is thinner than the gap portion, is used. One side in the width direction is adhered to the supporting member 11d by the double-sided tape 18 and the other side in the width direction. Is also adhered to the cleaning container 12c by the double-sided tape 18. At this time, the portion where the flexible sheet member 17 contacts the support member 11d and the cleaning container 12c (the portion adhered by the double-sided tape 18 in this embodiment) is not arranged at the same cross-sectional position. . This is the same as when the support member 11d and the cleaning container 12c are directly adhered to each other with the flexible sheet member 17 sandwiched when they are located at the same cross section, and they may be separated due to the difference in thermal expansion coefficient between the two. Because there is.

On the other hand, by preventing the bonding positions from being at the same cross-sectional position as in the present embodiment, even if the supporting member 11d or the like is thermally deformed due to the temperature change of the process cartridge B, the deformation amount thereof. Accordingly, the sheet member 17 itself extends due to the flexibility of the sheet member 17, and the double-faced tape 18 does not peel off. Therefore, the support member 11d
The toner does not leak from the gap between the cleaning container 12c and the cleaning container 12c.

Further, since the flexible sheet member 17 is thinner than the gap portion, the sheet member 17 itself does not apply a load to the supporting member 11d by thermal deformation of the sheet member 17, and the supporting member 11d is made of sheet metal. There is also no possibility of bending a certain support member 11d.

Therefore, it is possible to reliably prevent the toner leakage from the waste toner reservoir 11b and obtain a high quality image.

[Second Embodiment] Next, a cleaning container 12c
A second embodiment of the seal structure of FIG. 5 will be described with reference to FIG. The members having the same functions as those of the first embodiment described above are designated by the same reference numerals, and the duplicated description will be omitted.

The seal structure according to this embodiment is different from that of the first embodiment in that a flexible sheet thinner than 1/2 of the gap between the synthetic resin cleaning container 12c and the metal supporting member 11d. By using the member 17, the sheet member 17 is folded back so that the sheet member 17 has a bag shape, and the double-faced tape 18 adheres the sheet member 17 to the support member 11d and the cleaning container 12c. In this embodiment, the support member 11d
Although the adhesion position to the cleaning container 12c is set to the same cross-sectional position, the flexible sheet member 17 is folded back so that it is not peeled off even if the support member 11d or the like is thermally deformed.

Even with this structure, it is possible to reliably prevent toner leakage as in the first embodiment. In addition, in this embodiment, by folding back the flexible sheet member 17, it is possible to reduce the use area of the sheet member 17.

[Third Embodiment] Next, the cleaning container 12c.
A third embodiment of the seal structure of FIG. 6 will be described with reference to FIG. In this case as well, members having the same functions as those in the first embodiment described above are designated by the same reference numerals, and duplicate explanations are omitted.

In this embodiment, as the flexible sheet member 17, the support member 11d and the cleaning container are used as in the second embodiment.
A sheet that is thinner than 1/2 of the gap of the gap 12c is used, and the sheet member 17 is folded back to form a bag. However, unlike the second embodiment, the sheet member 17 has the double-sided tape 18 only on the cleaning container 12c side.
And the support member 11d side is not adhered. Thus, even if the sheet member 17 is not adhered to the support member 11d, the sheet member 17 is folded back and abuts the support member 11d at a predetermined angle with a force that does not warp the support member 11d.

By folding back the sheet member 17 in this way, even if the pressure in the waste toner reservoir 11b becomes high and the waste toner is about to be blown out, the sheet member 17 functions as a check valve and the toner is not discharged. It prevents the toner from leaking from the waste toner reservoir 11b.

Therefore, even with this structure, it is possible to reliably prevent toner leakage without warping the support member 11d as in the first and second embodiments. Furthermore,
With this configuration, the number of bonded portions is smaller than that in the second embodiment, and therefore the assembling property is also improved.

[Fourth Embodiment] Next, the cleaning container 12c.
A fourth embodiment of the seal structure of FIG. 7 will be described with reference to FIG. In this case as well, members having the same functions as those in the first embodiment described above are designated by the same reference numerals, and duplicate explanations are omitted.

In the above-mentioned first to third embodiments,
Although the flexible sheet member 17 is used to seal the gap between the support member 11d and the cleaning container 12c, in this embodiment, the flexible sheet is formed integrally with the squi sheet 11c. That is, as shown in FIG. 7, one end of the squi sheet 11c is adhered to the cleaning container 12c with the double-sided tape 18, and the squi sheet 11c is adhered to the lower surface of the support member 11d with the double-sided tape 18 so as to wind the support member 11d. In addition, the tip is configured to contact the photoconductor drum 7.

With this structure, the squeeze sheet 11c, which is a flexible sheet member, seals the gap between the support member 11d and the cleaning container 12c into a bag shape, which is substantially the same as that of the second embodiment. Therefore, even if the support member 11d, which is a sheet metal, is thermally deformed, the deformation is caused by the squeeze sheet 11c.
The toner does not leak from the gap portion, and the supporting member 11d is not bent.

Further, in this structure, since the flexible sheet member which is the seal member and the squishy sheet are integrally formed, the number of parts can be reduced.

[Fifth Embodiment] Next, the cleaning container 12c
A fifth embodiment of the seal structure of FIG. 8 will be described with reference to FIG. In this case as well, members having the same functions as those in the first embodiment described above are designated by the same reference numerals, and duplicate explanations are omitted.

In this embodiment, a flexible sheet member for sealing the gap is used as a squishy sheet as in the fourth embodiment.
This squishy sheet is integrated with 11c.
11c is folded back into a bag in the gap and double-sided tape
One side is adhered to the cleaning container 12c by 18 and the other side is adhered to the upper surface of the support member 11d, and the tip end thereof is brought into contact with the photosensitive drum 7. Even with this structure, the same effect as that of the fourth embodiment can be obtained.

[Other Embodiments] In the above-described embodiments, the squeegee sheet supporting member 11d of the cleaning means and the cleaning container 12c are used as the portions to be sealed by the flexible sheet member.
Although the gap portion is illustrated as an example, the present invention is not limited to this. In addition, the gap portion between the cleaning container 12c and a supporting member made of a metal plate or the like for supporting the cleaning blade 11a, or the developing means 10 may be used. The same can be applied to the case of sealing the gap between the toner container and the supporting member made of sheet metal or the like that supports the developing blade 10d.

Further, although polyethylene terephthalate is exemplified as the material of the flexible sheet member 17 in the above-mentioned embodiment, it is not necessary to limit to the above material as long as it is a flexible sheet capable of maintaining the sealing property.

Further, the process cartridge B according to the present invention
Not only when forming a single color image as described above,
By providing a plurality of developing means, a multi-color image (for example, a two-color image,
It can also be suitably applied to a cartridge that forms a three-color image or full-color image.

Further, the image bearing member is not limited to the above-mentioned photosensitive drum, but includes, for example, the following. First, a photoconductor is used as the photoconductor, and as the photoconductor, for example, amorphous silicon, amorphous selenium,
Zinc oxide, titanium oxide, organic photoconductor (OPC) and the like are included. The shape on which the photoconductor is mounted includes, for example, a drum-shaped, belt-shaped rotating body, a sheet-shaped body, and the like. Generally, a drum-shaped or belt-shaped one is used. For example, in the case of a drum type photoconductor, a photoconductor is vapor-deposited or coated on a cylinder of aluminum alloy or the like. Is.

As the developing method, it is possible to use various developing methods such as a known two-component magnetic brush developing method, cascade developing method, touch-down developing method, cloud developing method and the like.

As for the structure of the charging means, the so-called contact charging method was used in the above-described first embodiment, but a tungsten wire which has been conventionally used as another structure is provided with a metal shield such as aluminum around three sides. It goes without saying that a configuration may be used in which positive or negative ions generated by applying a high voltage to the tungsten wire are moved to the surface of the photosensitive drum to uniformly charge the surface of the drum.

The charging means may be of a blade type (charging blade), a pad type, a block type, a rod type, a wire type or the like, other than the roller type.

Further, as a method for cleaning the toner remaining on the photosensitive drum, the cleaning means may be constituted by using a blade, a fur brush, a magnetic brush or the like.

The process cartridge described above is
For example, an electrophotographic photosensitive member as an image carrier and at least one process means are provided. Therefore, as the mode of the process cartridge, in addition to the embodiment described above, for example, the image carrier and the charging means are integrally made into a cartridge, which can be attached to and detached from the apparatus main body. The image carrier and the developing means are integrally formed into a cartridge, which can be attached to and detached from the main body of the apparatus. The image carrier and the cleaning means are integrally made into a cartridge so that it can be attached to and detached from the apparatus main body. Further, there is one in which an image carrier and two or more of the above-mentioned process means are combined into an integrated cartridge, which can be attached to and detached from the apparatus main body.

That is, the above-mentioned process cartridge is one in which the charging means, the developing means or the cleaning means and the electrophotographic photosensitive member are integrally made into a cartridge, and the cartridge can be attached to and detached from the main body of the image forming apparatus. . Further, at least one of the charging means, the developing means, and the cleaning means and the electrophotographic photosensitive member are integrally made into a cartridge so that it can be attached to and detached from the main body of the image forming apparatus. Further, it means that at least the developing means and the electrophotographic photosensitive member are integrally made into a cartridge so as to be attachable to and detachable from the apparatus main body.

Further, in the above-described embodiment, the photosensitive drum and the developing roller are made into a cartridge, and the apparatus for forming the image by mounting this process cartridge is exemplified. However, these photosensitive drum and the developing roller are not made into a cartridge, The present invention can be similarly applied to an image forming apparatus directly attached to the apparatus main body. That is, an image carrier photoconductor drum, a developing device for forming a toner image on the photoconductor drum, a transfer device for transferring the toner image onto a recording medium, and a photoconductor drum after the toner image transfer. Cleaning means for removing the toner remaining on the
When the gap between the supporting member, which has a conveying means for conveying the recording medium and which supports the cleaning sheet of the cleaning means, and the gap between the waste toner container and the waste toner container is sealed, the above-described first to third embodiments are used. The same effect can be obtained by using the structure shown in the fifth embodiment.

Further, although the laser beam printer is exemplified as the image forming apparatus in the above-mentioned embodiments, the present invention is not limited to this, and other image forming apparatus such as an electrophotographic copying machine, a facsimile machine, a word processor, etc. It is also possible to use for.

[0056]

As described above, according to the present invention, when sealing the gap where the first wall surface and the second wall surface made of different materials face each other, the flexible sheet member is formed on the first wall surface and the second wall surface. Since the first wall surface made of metal and the second wall surface made of synthetic resin are contacted with each other and at least one of them is adhered to the wall surface, a difference in thermal expansion coefficient causes a deviation due to thermal deformation. Also, even if a deviation due to impact occurs, the deviation can be absorbed by the flexible sheet member, and the developer can be prevented from leaking from the gap between both wall surfaces.

Therefore, if the process cartridge or the toner container of the image forming apparatus is sealed with the above-mentioned sealing structure, a high-quality image can be obtained without causing toner leakage.

By forming the flexible seal member integrally with the squishy sheet, it is possible to effectively prevent toner leakage without increasing the number of parts.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a seal configuration of a cleaning container according to a first embodiment.

FIG. 2 is a configuration explanatory diagram of an image forming apparatus in which a process cartridge is mounted.

FIG. 3 is a configuration explanatory view of a process cartridge.

FIG. 4 is a diagram illustrating the mounting of the process cartridge.

FIG. 5 is an explanatory diagram of a seal configuration of the cleaning container according to the second embodiment.

FIG. 6 is an explanatory diagram of a seal configuration of a cleaning container according to a third embodiment.

FIG. 7 is an explanatory diagram of a seal configuration of a cleaning container according to a fourth embodiment.

FIG. 8 is an explanatory diagram of a seal structure of a cleaning container according to a fifth embodiment.

FIG. 9 is an explanatory diagram of a conventional technique.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Optical system, 2 ... Recording medium, 3 ... Conveying means, 4 ... Transfer roller, 5 ... Fixing means, 6 ... Ejecting section, 7 ... Photosensitive drum,
8 ... Charging roller, 9 ... Exposure part, 10 ... Developing means, 11 ... Cleaning means, 11a ... Cleaning blade, 11b ... Waste toner reservoir, 11c ... Squeeze sheet, 11d ... Support member, 12
a ... toner container, 12b ... development frame, 12c ... cleaning container, 12d ... shutter member, 13 ... apparatus body, 14 ... front unit, 15 ... mounting means, 16 ... double-sided tape, 17 ... flexible sheet member, 18 …Double-sided tape

Claims (11)

[Claims] 1. A process cartridge attachable to and detachable from a main body of an image forming apparatus, wherein an image carrier, at least one process unit acting on the image carrier, and a first wall surface and a second wall surface made of different materials face each other. A flexible sheet member that seals the existing gap, and the flexible sheet member is brought into contact with the first wall surface and the second wall surface, and at least one of the contact surfaces is bonded to the wall surface. Characteristic process cartridge. 2. The abutting portion of the flexible sheet member that abuts the first wall surface and the second wall surface does not have the same cross-sectional position, and one abutting portion of the flexible sheet member is formed. The process cartridge according to claim 1, wherein the process cartridge is adhered to the first wall surface and the other contact portion is adhered to the second wall surface. 3. The process cartridge according to claim 1, wherein the flexible sheet member is folded back between the gap portions. 4. The process cartridge according to claim 1, wherein the first wall surface is a support member made of metal for supporting the squi sheet, and the second wall surface is a frame body made of synthetic resin. 5. The process cartridge according to claim 1, wherein the flexible sheet member is configured integrally with the squishy sheet. 6. An image forming apparatus, wherein a process cartridge is attachable / detachable and forms an image on a recording medium, an image carrier, at least one process unit acting on the image carrier, and a first member made of a different material. A flexible sheet member for sealing a gap portion where the wall surface and the second wall surface face each other, and the flexible sheet member is brought into contact with the first wall surface and the second wall surface, and at least the contact is made. Mounting means for mounting the process cartridge by bonding one to the wall surface, transfer means for transferring the image formed on the image carrier to a recording medium, and conveying means for conveying the recording medium. An image forming apparatus comprising: 7. An image forming apparatus for forming an image on a recording medium, an image carrier, a developing unit for forming a developed image on the image carrier, and a transfer for transferring the developed image to the recording medium. Means, a cleaning means for removing the developer remaining on the image carrier after the transfer of the developed image, a conveying means for conveying the recording medium, and a first wall surface and a second wall surface made of different materials face each other. A flexible sheet member for sealing the gap portion, and the flexible sheet member is brought into contact with the first wall surface and the second wall surface, and at least one of the contacting surfaces is bonded to the wall surface. An image forming apparatus characterized by. 8. The abutting portion of the flexible sheet member that abuts against the first wall surface and the second wall surface does not have the same cross-sectional position, and one abutting portion of the flexible sheet member is formed. The image forming apparatus according to claim 7, wherein the first contact surface is adhered to the first wall surface and the other contact portion is adhered to the second wall surface. 9. The image forming apparatus according to claim 7, wherein the flexible sheet member is folded back between the gap portions. 10. The image forming apparatus according to claim 7, wherein the first wall surface is a metal support member for supporting the squi sheet, and the second wall surface is a frame body made of synthetic resin. . 11. The image forming apparatus according to claim 7, wherein the flexible sheet member is formed integrally with the squishy sheet.