JP2001005287A - Developing device, process cartridge, developing unit cartridge and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent developer from being leaked from a rubbing part and to reduce load imposed on a motor by making a sheet-like member covering over a rubbing boundary part between a both-end developer leakage preventing member and a developer carrier project to the center part side in the longitudinal direction of the aperture part of a developing unit housing from the back position of a rubbing surface. SOLUTION: A Teflon(R) felt 113 constituting the uppermost layer of the both-end developer leakage preventing member is attached over the sheet metal 64b of a layer thickness regulating blade 64, a blade side seal on a front side 112, an intermediate layer film 109 and a seal attaching area on a side by using a double coated adhesive tape. The film 109 is attached to the back side of the felt 113, and the end of the film 109 is made to project to the center part side in the longitudinal direction of a case 51. Therefore, even when much toner is supplied to a press-contact part between a supply roller 58 and a developing roller, it is interrupted by the film 109, so that the toner reaching the rubbing surface between the felt 113 and the developing roller is remarkably reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technical field of a developing apparatus, a process cartridge, a developing cartridge, and an image forming apparatus provided with any one of them for developing using a developer which is charged fine particles. Belong to.

[0002]

2. Description of the Related Art In a developing device which uses a toner, which is charged fine particles, as a developer and electrostatically adheres the toner to an electrostatic latent image to perform development, there is a problem that the toner leaks from the developing device. is there. If the toner leaks from the developing device, the inside of the image forming apparatus main body equipped with the developing device becomes dirty, resulting in poor printing, and further, when the developing device is replaced, the hands and clothes of the worker become dirty. There was sometimes.

In particular, a non-magnetic one-component developing a thin layer of toner on a developing roller having a function of carrying and transporting the toner by using a layer thickness regulating blade and facing the electrostatic latent image. In the case of development, toner is likely to leak from around the rotating developing roller.

Conventionally, the above-described toner leakage has been prevented by providing a toner leakage prevention member inside the developing device. For example, in order to prevent toner leakage from both ends of the developing roller around the developing roller, a toner leakage preventing member called a side seal is rubbed against the peripheral surfaces of both ends of the developing roller, In order to prevent toner from leaking from the gap between the developing roller formed below and the opening of the toner container, a toner leak preventing member called a lower film is rubbed against the developing roller below the developing roller. . Further, in order to prevent toner from leaking from the gap between the developing roller formed above the developing roller and the opening of the toner container, the layer thickness regulating blade is pressed against the developing roller, and the layer thickness is reduced. The regulating blade has a function as a toner leakage preventing member.

The side seal has a structure in which a sliding member made of Teflon felt is attached to a urethane sponge. Urethane sponges are required to be sufficiently soft and have low compression set. Teflon felt is used for both securing the pressing force and reducing the rotational torque.

The lower film is made of PET (polyethyle).
ne terephthalate) sheet, urethane rubber or the like is used. Although urethane rubber can be expected to be softly pressed, it is necessary to press it with a sponge or the like from the back because it has no waist. Since the PET sheet is harder than the urethane rubber film, there is no need to press with a sponge or the like from the back, and there is an advantage that the assembling work is easier than the urethane rubber film.

[0007]

However, when this configuration is adopted, if a small amount of toner enters between the developing roller and the side seal, the developing roller and the side seal are damaged by the entered toner. There was a problem. Even if a small amount of toner enters first, the degree of damage increases as printing is repeated due to damage to the side seal, and toner leakage gradually increases.

In particular, when a polymerized toner having a spherical shape and extremely excellent fluidity is used, the toner easily enters between the side seal and the developing roller.
When the side seals and the like are damaged, toner leakage is more remarkable when polymerized toner is used, and there is a problem that the amount of leaked toner is significantly increased.

In order to prevent such toner leakage, it is conceivable to increase the pressure of the side seal against the developing roller. However, in such a case, the rotational torque of the developing roller becomes too high, and the motor is not supplied to the motor. This causes a problem that the load on the device increases.

Further, when a polymerized toner is used, it is difficult to completely prevent toner leakage even if pressure is increased.

In particular, when a system in which the supply roller is rubbed against the development roller is employed in order to improve the supply of the toner to the development roller, a large amount of toner is generated in the vicinity of the pressure contact portion between the supply roller and the development roller. There is a problem that the toner gathers, the toner density increases, and the toner easily enters between the side seal and the developing roller.

Accordingly, the present invention solves such a problem and can reliably prevent toner from leaking from the rubbing portion between the developing roller and the side seal even when the polymerization toner and the supply roller are used. It is an object to provide a developing device, a process cartridge, a developing device cartridge, and an image forming apparatus.

[0013]

According to a first aspect of the present invention, there is provided a developing device, wherein a developer carrier is rotatably disposed in an opening of a developing device housing for accommodating a developer. ,
A developing device for forming a visible image by causing a thin layer of developer formed on the developer carrier to face an electrostatic latent image, wherein the developing device housing has an opening near the longitudinal end of the opening thereof. A developer leakage prevention member at both ends provided to rub against the peripheral surfaces on both ends of the developer carrying member, and a back surface of a sliding surface of the both ends of the developer leakage preventing member against the developer carrying member. A sheet-like member that is provided at a position, and covers a rubbing boundary between the developer leakage preventing member and the developer carrying member and a periphery of the rubbing boundary. It is characterized in that it is provided so as to protrude from the position toward the center in the longitudinal direction of the developing device housing opening.

According to the first aspect of the present invention, the developer carrying member carries and transports the developer while rotating. The developer carrying member is provided near the longitudinal ends of the opening of the developing device housing. Since the developer leakage preventing members are provided so as to rub against the peripheral surfaces of both ends of the developer, the leakage of the developer from both ends is prevented. In addition, a sheet-like member is provided at a rear position of a sliding surface of the developer leakage prevention member with the developer carrying member at both ends, and the sheet-like member is moved from the rear position to a longitudinal direction of the developing device housing opening. It protruded toward the center. Thus, the rubbing boundary between the developer leakage preventing member and the developer carrier at both ends and the periphery of the rubbing boundary are covered by the sheet-shaped member, so that the developer leakage preventing member at both ends and the developing member are developed. The developer density at the rubbing boundary portion with the developer carrier and around the rubbing boundary portion is reduced, and the developer enters the rubbing portion between the developer leakage prevention member at both ends and the developer carrier. There is no. As a result, leakage of the developer from the rubbing portion is reliably prevented.

According to a second aspect of the present invention, in order to solve the above-mentioned problem, in the developing device according to the first aspect, the developer leakage preventing members at both ends are provided on a base portion attached to the developing device housing. And a rubbing portion attached to the base portion and rubbing against the developer carrier, wherein the sheet-like member is sandwiched between the base portion and the rubbing portion. It is characterized by.

According to the second aspect of the present invention, the rubbing portions of the developer leakage preventing members at both ends are pressed by the base portion attached to the developing device housing, and rub against the developer carrier. So it contacts the developer carrier without forming a gap,
Prevents developer leakage. Moreover, since the sheet-like member is sandwiched between the base member and the rubbing part,
The rubbing boundary between the rubbing portion and the developer carrier and the periphery of the rubbing boundary are covered with the sheet-like member.
As a result, the developer density in the rubbing boundary portion and in the vicinity of the rubbing boundary portion decreases, and the developer does not enter between the rubbing portion and the developer carrier, and the developer leaks. Is reliably prevented.

According to a third aspect of the present invention, in order to solve the above-mentioned problem, in the developing device according to the first or second aspect, the developing device is rotatably disposed while rubbing the developer carrier. The image forming apparatus further includes a developer transport supply unit made of a foamed elastic body that transports and supplies the developer to the carrier, and a protruding portion of the sheet-shaped member is provided between the developer carrier and the developer transport supply unit. It is characterized by being pinched.

According to the third aspect of the present invention, the developer transport supply member made of a foamed elastic body rotates while rubbing against the developer carrier while pressing against the developer carrier, and transports the developer to the developer carrier. Supply. Therefore, a large amount of the developer is supplied to the pressure contact portion between the developer transport supply member and the developer carrier, and the developer density at the pressure contact portion increases. However, since the protruding portion of the sheet-shaped member is sandwiched between the developer carrying member and the developer conveying / supplying member, the developer in the press-contact portion exceeds the sheet-shaped member and the developer at both ends thereof The developer is prevented from being conveyed to the rubbing boundary between the leakage prevention member and the developer carrying member and around the rubbing boundary, and the developer density at the rubbing boundary and around the rubbing boundary Decrease. As a result, the developer does not enter the rubbing portion between the developer leakage preventing member and the developer carrying member at both ends, and the leakage of the developer from the rubbing portion is reliably prevented.

According to a fourth aspect of the present invention, in order to solve the above-mentioned problem, in the developing device according to the first aspect, the sheet-like member is formed of a resin. And

According to the fourth aspect of the present invention, since the sheet-shaped member is formed of resin, the sheet-shaped member has appropriate hardness, reliably prevents intrusion of the developer, and is appropriately deformed. It becomes easy to form the shape along the peripheral surface of the developer carrying member.

According to a fifth aspect of the present invention, in order to solve the above-mentioned problem, in the developing device according to the fourth aspect, the sheet-like member is formed of PET.

According to the fifth aspect of the present invention, since the sheet-like member is formed of PET, the sheet-like member has an appropriate hardness, reliably prevents intrusion of the developer, and is appropriately deformed. It becomes easy to form the shape along the peripheral surface of the developer carrying member.

According to a sixth aspect of the present invention, there is provided a developing device according to any one of the first to fifth aspects, wherein the sheet-like member has a longitudinal direction of the developer carrying member. Is provided along the notch.

According to the sixth aspect of the present invention, since the sheet-shaped member is provided with a cut along the longitudinal direction of the developer carrier, even if a load accompanying rotation of the developer carrier is applied. In addition, the sheet-like member itself is not broken.

According to a seventh aspect of the present invention, in order to solve the above-mentioned problems, in the developing device according to the first aspect of the present invention, the sheet-like member includes a developer leakage prevention member at both ends. The length along the longitudinal direction of the portion protruding toward the center in the longitudinal direction of the opening of the developing device housing from the rubbing boundary with the developer carrying member is 1 mm or more and 4 mm or more.
It is characterized by the following.

According to the seventh aspect of the present invention, the sheet-like portion is positioned in the longitudinal direction of the opening of the developing device housing with respect to the sliding boundary between the developer leakage preventing member and the developer carrying member at both ends. Since the protruding portion is made to protrude toward the center and the length of the protruding portion along the longitudinal direction is set to 1 mm or more, the amount of the developer exceeding the protruding portion is reliably reduced to prevent the developer from leaking. In addition, since the length of the protruding portion along the longitudinal direction is 4 mm or less, the convection of the developer is not deteriorated in the vicinity of the tip of the protruding portion, and the toner is prevented from being deteriorated.

According to an eighth aspect of the present invention, in order to solve the above-mentioned problem, in the developing device according to any one of the first to seventh aspects, the developer is a polymerized toner produced by a polymerization method. It is characterized by the following.

According to the developing device of the present invention, since the polymerized toner produced by the polymerization method is used as the developer, the fluidity is high and the developer easily leaks. Since the developer member reduces the developer density at and around the boundary between the developer leakage preventing member and the developer carrier, the toner leakage does not occur.

According to a ninth aspect of the present invention, a process cartridge is provided.
9. A process cartridge detachably formed in an image forming apparatus for solving the above-mentioned problem, comprising: a carrier for the electrostatic latent image; and a developing device according to claim 1. It is characterized by having.

According to the process cartridge of the ninth aspect, the process cartridge detachably formed in the image forming apparatus is provided with the developing device of any one of the first to eighth aspects. Even when the cartridge is attached or detached, the developer is reliably prevented from leaking.

The developing device cartridge according to claim 10 is
In order to solve the above-mentioned problem, a developing device according to any one of claims 1 to 8 is formed so as to be detachable from an image forming apparatus or a process cartridge.

According to the tenth aspect of the present invention, the developing device according to any one of the first to eighth aspects is formed detachably with respect to the image forming apparatus or the process cartridge. The leakage of the developer is surely prevented even during the attachment and detachment.

According to an eleventh aspect of the present invention, there is provided an image forming apparatus according to any one of the first to eighth aspects of the invention, or the process cartridge according to the ninth aspect or the tenth aspect of the present invention. A developing device cartridge is provided.

According to the image forming apparatus of the eleventh aspect,
Since the developing device according to any one of claims 1 to 8, the process cartridge according to claim 9, or the developing device cartridge according to claim 10 is provided, the developer does not leak and the inside of the image forming apparatus main body is not generated. Is not contaminated by the developer.

[0035]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. First, an overview of the entire image forming apparatus according to the present embodiment will be described.

FIG. 1 is a sectional view showing a schematic configuration of a laser beam printer 1 as an embodiment of the image forming apparatus of the present invention. In FIG. 1, the laser beam printer 1 includes a feeder unit for feeding paper (not shown) at the bottom of a main body case 2. The feeder unit includes a paper pressing plate 10 that is pressed by a spring (not shown), a paper feeding roller 11, and a friction separating member 14. The uppermost sheet is separated between the feed roller 11 and the friction separating member 14 by the rotation of the roller, and the sheet is supplied at a predetermined timing.

A pair of registration rollers 12 and 13 are rotatably supported on the downstream side in the sheet transport direction by the rotation of the sheet supply roller 11 rotating in the direction of the arrow in FIG. The sheet is conveyed to a transfer position formed by the transfer roller 21 at a predetermined timing.

The photosensitive drum 20 is made of a positively chargeable material, for example, an organic photoreceptor mainly composed of positively chargeable polycarbonate. More specifically, the photosensitive drum 20 has, for example, a cylindrical aluminum sleeve as a main body, and has a predetermined thickness (for example, about 20 μm) in which a photoconductive resin is dispersed in polycarbonate on an outer peripheral portion thereof. It is composed of a hollow drum on which a conductive layer is formed, and is rotatably supported by the main body case 2 with the cylindrical sleeve grounded. Further, the photosensitive drum 20 is driven to rotate in a direction indicated by an arrow by driving means (not shown).

The charger 30 is composed of a scorotron type charger for positive charging for generating corona discharge from a charging wire made of, for example, tungsten.

The laser scanner unit 40 includes a laser generator (not shown) that generates a laser beam L for forming an electrostatic latent image on the photosensitive drum 20, and a polygon mirror (pentahedral mirror) 41 that is driven to rotate. , A pair of lenses 42 and 4
5 and reflection mirrors 43, 44 and 46.

In the developing device 50, a toner accommodating chamber 52 as a developer chamber is formed in a case 51 as a developing device housing. In the toner accommodating chamber 52, an agitator 53 and a cleaning member 54 are provided with a rotating shaft 55. It is provided rotatable around. The toner accommodating chamber 52 accommodates a positively chargeable nonmagnetic one-component developer having electrical insulation. The rotation shaft 55 of the toner storage chamber 52
Light transmitting windows 56 are provided on the side walls located at both ends of the light emitting element. On the photosensitive drum 20 side of the toner accommodating chamber 52, a developing chamber 57 that communicates with the toner accommodating chamber 52 through the opening A to perform development is formed, and a supply roller 58 and a developing roller 59 as a developer carrier are rotated. Pivot as possible.
The toner on the developing roller 59 is regulated to a predetermined layer thickness by a thin plate-like elastic layer thickness regulating blade 64 and is used for development.

Here, a developing roller 59 as a developer carrying member is a cylindrical metal formed of conductive silicone rubber containing fine particles of conductive carbon on a metal core formed of stainless steel or the like. A base material is provided, and a coat layer of a resin or rubber material containing fluorine is formed on the base material. The base of the developing roller 59 does not necessarily have to be made of conductive silicone rubber, and may be made of conductive urethane rubber.

The supply roller 58 as a developer transport supply member has a cylindrical base made of urethane rubber sponge, which is a conductive elastic foam, formed on a metal core made of stainless steel or the like. The roller is arranged so as to be pressed against the developing roller 59 by the elastic force of the urethane rubber sponge. In addition, as the supply roller 58, an appropriate member such as a conductive silicone rubber foam may be used.

The toner accommodated in the toner accommodating chamber 52 is a positively charged non-magnetic one-component developer, and a styrene-acrylic resin formed into a spherical shape by a suspension polymerization method, such as carbon black or the like. The toner base particles have a particle diameter of 6 μm to 10 μm and an average particle diameter of 8 μm to which a well-known coloring agent and a charge control agent such as nigrosine, triphenylmethane, and quaternary ammonium salt are added. The toner is configured by adding silica as an external additive to the surface of the toner base particles.

The transfer roller 21 is rotatably pivotally supported,
It is made of a conductive foamed elastic body made of silicone rubber or urethane rubber. The transfer roller 21 is configured to reliably transfer the toner image on the photosensitive drum 20 to the paper by the applied voltage.

The fixing unit 70 includes the registration roller 12
The heating roller 71 and the pressing roller 72 are provided on the further downstream side in the sheet conveyance direction from the sheet feeding roller 13 to the pressure contact portion between the photosensitive drum 20 and the transfer roller 21. The toner image transferred to the sheet is heated and pressed while being conveyed by the heating roller 71 and the pressing roller 72 and is fixed on the sheet.

A pair of transport rollers 73 and a paper discharge roller 74 for paper transport are provided on the downstream side of the fixing unit 70 in the transport direction, and a paper output tray 75 is provided on the downstream side of the paper discharge roller 74. Have been.

The above-described photosensitive drum 20, transfer roller 21, charger 30, and developing device 50 are housed in a drum cartridge 2a, which is detachably attached to the laser beam printer 1. Is provided. Further, the developing device 50 is provided detachably with respect to the drum cartridge 2a (process cartridge of claim 10) as a developing device cartridge.

In the laser beam printer 1 of the present embodiment as described above, the surface of the photosensitive drum 20 is
When the laser beam L modulated according to image information is emitted from the laser scanner unit 40, an electrostatic latent image is formed on the surface of the photosensitive drum 20.
This electrostatic latent image is visualized with toner by the developing device 50, and the visible image formed on the photosensitive drum 20 is transported by the photosensitive drum 20 to a transfer position. At the transfer position, the paper is supplied via the paper feed roller 11 and the registration rollers 12 and 13, and the visible image is transferred to the paper by a transfer bias applied by the transfer roller 21. The toner remaining on the photosensitive drum 20 after the transfer is collected in the developing chamber 57 by the developing roller 59.

Next, the sheet is conveyed to the fixing unit 70, and is nipped and conveyed by the heating roller 71 and the pressing roller 72 of the fixing unit 70, and the visible image on the sheet is pressed and heated to be fixed on the sheet. You. Then, the sheet is discharged to the discharge tray 75 above the laser beam printer 1 by the pair of transport rollers 73 and the discharge rollers 74, and the image forming operation is completed.

(Seal Structure in Developing Apparatus) Next, a seal structure using a developer leakage preventing member in the developing apparatus 50 of the present embodiment will be described with reference to FIGS. I do.

FIGS. 2 (A), 3 (A), 4 (A), 5 (A), 6 (A), 7 (A), 8 (A), 1
1 (A), FIG. 12 and FIG.
5 is a partially cutaway perspective view showing a seal portion of a case 51 in FIG. 2 (B), FIG. 3 (C), FIG. 4 (C), FIG. 5 (B), FIG. 6 (B), FIG. 7 (B), FIG.
1 (B) and FIG. 14 (C) are views showing the seal portion viewed from the direction of arrow B shown in each of the partially cutaway perspective views. FIG. 3B is a sectional view taken along line CC of FIG.
FIG. 8B is a diagram showing the seal portion viewed from the direction of arrow A shown in FIG. 4A, FIG. 8B is a diagram showing the seal portion viewed from the direction of arrow A shown in FIG. Is a front view showing a seal portion of the case 51 at a stage where the upper seal is attached, FIG. 10 is a view showing the seal portion viewed from the direction of arrow B shown in FIG. 9, and FIG. 13 (B) is a diagram of the layer thickness regulating blade viewed from the front side, FIG. 13 (C) is a diagram showing a seal portion viewed from the direction of arrow B similarly to FIG. 11 (B), and FIG. (B) is FIG. 14 (A)
FIG. 14 is a diagram showing a seal portion viewed from the direction of arrow A shown in FIG.
(D) is a sectional view taken along line DD of FIG. 14 (C), and FIG.
Is a plan view showing the lower film and its surroundings,
FIG. 15 (B) is a view showing the bonding surface of the lower film, and FIG.
14A is a partially cutaway perspective view showing a seal portion of the case 51 on the opposite side to FIG. 14A, and FIG.
FIG. 5 is a view showing a seal portion viewed from the direction of arrow B as shown in FIG.

First, in FIG. 2A, an area indicated by oblique lines is an area where a seal member described below is attached with a double-sided tape, and a side seal attachment area 100 along the circumferential direction of the developing roller 59 is provided. , Developing roller 5
9 is divided into a lower seal mounting area 101 along the longitudinal direction of the developing roller 59. Side seal mounting area 100 and lower seal mounting area 101
Is subjected to a degreasing treatment in order to enhance the adhesiveness of the double-sided tape.

The developing roller 59 is arranged so that its end face is close to the side face 51a of the developing roller accommodating portion of the case 51 shown in FIG. FIG. 2 (B)
The center point Q shown in FIG. 7 indicates the position of the rotation center axis of the developing roller 59. The supply roller 58 is attached to a supply roller housing provided at a position behind the developing roller housing, as indicated by a two-dot chain line in FIG.

Next, as shown in FIGS. 3A, 3B, and 3C, the end face of the bottom portion 51b of the developing roller accommodating portion following the lower seal mounting region 101 on the side seal mounting region 100 side. 51c, and the side edge seal 102 is attached to the side side seal mounting area 1 with a double-sided tape.
Attach it to 00. The double-sided tape is attached to the bottom of the side edge seal 102, and the side edge seal 10
The end face 2 is pressed against the end face 51c of the bottom surface portion 51b on the side-side seal mounting area 100 side to be brought into close contact therewith. As shown in FIG. 3B, the side seal mounting area 100 has a bottom surface portion 51 in consideration of the thickness of a side seal described later.
b, and a step having an end face 51c is formed between the bottom face 51b and the side seal mounting area 100. Side seal installation area 1
00, the side seal 10 as shown by the dotted line in FIG.
4, the end face 51c is attached to the side seal 10
4 comes into contact with the end face of the side seal 104.
, A urethane sponge having relatively high rigidity among sponges is used, so that the adhesiveness to the resin forming the case 51 is weakened, and the end face 51 c and the side seal 104 are used.
Toner enters the contact portion with the end surface of the toner, and toner leakage occurs. The intrusion of the toner is not limited to the intrusion through the bottom surface 51b, but also from the supply roller housing. Therefore, in the present embodiment, the side edge seal 102 formed of a sponge softer than the urethane sponge is brought into close contact with the end face 51c to reliably prevent such intrusion of the toner.

Next, as shown in FIGS. 4A, 4B and 4C, the film 103 for attaching the upper side seal is formed.
To the case 51 using a double-sided tape. A blade side seal for preventing toner leakage from both end portions is attached to the layer thickness regulating blade 64, and an upper side seal for improving adhesion to the blade side seal is provided on the case 51 side. It is attached. This upper side seal is attached so as to be superimposed on the film 103 shown in FIG. 4B, but if there is no film 103, the bonding area of the upper side seal to the case 51 is indicated by hatching in FIG. 4B. Only the region shown indicates lack of stability. Therefore,
In the present embodiment, the PET film 103 is
1 to secure the bonding area of the upper side seal.

Next, as shown in FIGS. 5A and 5B,
In order to prevent toner from leaking from the end of the developing roller 59, a side seal 104 constituting a base material of a developer leak preventing member at both ends is attached to the side seal attaching area 100 with a double-sided tape. The side seal 104 is formed of a urethane sponge (trade name: Poron, manufactured by Rogers INOAC) having relatively high rigidity among sponges, and is compressed when the developing roller 59 is attached so as to exert a predetermined pressing force. It has a certain thickness. With such a configuration, Teflon felt, which is the uppermost layer of the both-end developer leakage prevention member described below,
The developing roller 59 can be pressed with a predetermined pressing force.

In this embodiment, FIG.
As shown in (1), the side end surface of the supply roller 58 is configured to rub against the side end surface of the side seal 104, so that toner leakage from between the supply roller 58 and the side seal 104 is prevented.

Next, as shown in FIGS. 6A and 6B,
In order to prevent toner leakage from the boundary between the lower seal mounting area 101 and the side seal mounting area 100 and toner leakage from a gap between a movable section of the lower seal and the lower seal mounting area 101, which will be described later. The side seal 105 is attached to the lower seal mounting area 10 with a double-sided tape.
Attach to one end. The lower side seal 105 is formed of a soft urethane sponge, and a double-sided tape is attached to the bottom surface of the lower side seal 105. The end face on the side seal 104 side is attached so as to overlap in a partial area W0 as shown in FIG. 6B, and the lower side seal 105 is brought into close contact with the side seal 104 by pressing.
In the present embodiment, the overlapping area W0 is set to about 2 mm.

Next, as shown in FIGS. 7A and 7B,
Adhesive surface of side seal 104 of case 51 and film 1
The edge seal 106 is attached from the stepped portion E formed between the adhesive surface 03 and the upper surface of the side seal 104. The edge seal 106 is formed of a soft urethane sponge, and is adhered to the step portion E and the upper end surface of the side seal 104 by attaching a double-sided tape to the bottom surface. By providing such an edge seal 106, the lower end face of the upper side seal attached to the film 103 and the blade side seal attached to the layer thickness regulating blade, to which the double-sided tape is not attached, is brought into contact with the edge seal 106. Thus, a contact portion between the sponge and the sponge can be formed to reliably prevent the toner from leaking.

Next, as shown in FIGS. 8 (A), 8 (B) and 8 (C), the upper side seal 107 is attached to the film 103 in order to enhance the adhesion with the blade side seal described later.
And attached to the case 51 with double-sided tape. The upper side seal 107 is also formed of a soft urethane sponge, and is provided at a position in contact with a blade side seal described later. With such a configuration, the contact portion between the upper side seal 107 and the blade side seal becomes a contact portion between the sponge and the sponge, so that toner leakage can be reliably prevented.

Next, as shown in FIGS. 9 and 10, in order to prevent toner from leaking from an upper position behind the mounting portion of the layer thickness regulating blade 64, the layer thickness regulating blade 64 is formed to extend in the longitudinal direction. The mounted upper seal 108 is attached. The upper seal 108 is formed of a soft urethane sponge. With this upper seal 108,
It is possible to reliably prevent toner leakage due to toner spraying in the toner storage chamber or toner leakage when the developing device 50 is turned upside down.

Next, as shown in FIGS. 11A and 11B, an intermediate layer film 109 as a sheet-like member constituting an intermediate layer of a developer leakage prevention member at both ends is mounted on the side seal 104. . The film 109 is formed of PET, and the side seal 104 is made of a double-sided tape.
Pasted in. The intermediate layer film 109 is shown in FIG.
As shown in (A), a protrusion is formed which is wider than the side seal 104 and whose end protrudes toward the center of the case 51. With this configuration, it is possible to reduce the toner density near the pressure contact portion between the Teflon felt attached to the intermediate layer film 109 and the developing roller, as described later, and to reduce the toner pressure on the pressure contact portion. be able to. As a result, toner leakage can be reliably prevented without increasing the pressing force of the side seal 104 against the developing roller 59 more than necessary.

In particular, in this embodiment, as shown in FIG. 11A, the supply roller 58 is shorter than the length of the developing roller 59, and as shown in FIG. 5A or FIG. Since the side end surface of the roller 58 is configured to rub against the side end surface of the side seal 104, unnecessary toner leakage from a contact portion between the side end surface of the supply roller 58 and the side end surface of the side seal 104 is prevented. However, the supply roller 58
A large amount of toner is conveyed to the pressure contact portion between the roller and the developing roller 59 by the toner conveyance function of the supply roller 58, so that the toner density around the pressure contact portion becomes extremely high.
As a result, the side end face of the supply roller 58 and the side seal 10
The toner density also increases around the rubbing portion with the side end surface of No. 4.

However, in the present embodiment, since the end of the intermediate layer film 109 is configured to protrude toward the center of the case 51, the toner around the rubbing portion develops beyond the intermediate layer film 109. Coming to the roller 59 side can be reduced.

As shown in FIG. 11A, a cutout portion 109a is provided at the projecting portion of the intermediate layer film 109 from the center of the case 51 along the longitudinal direction of the developing roller 59. Developing roller 59 and supply roller 5
The intermediate layer film 109 is prevented from being torn by the deformation caused by the load caused by the rotation of the motor 8.

That is, the intermediate layer film 109 was
By being configured to protrude toward the center of the first roller 1, this protruding portion is sandwiched between the developing roller 59 and the supply roller 58. Since Teflon felt is provided on the intermediate layer film 109 as described later, there is a small gap between the developing roller 59 and the intermediate layer film 109 corresponding to the thickness of Teflon felt. However, the supply roller 58 is pressed by the projecting portion of the intermediate layer film 109, so that the intermediate layer film 10
The projecting portion 9 slightly comes into contact with the developing roller 59 as well. Therefore, the projecting portion of the intermediate layer film 109 is sandwiched between the developing roller 59 and the supply roller 58, and is deformed as the developing roller 59 and the supply roller 58 rotate.

However, by providing the cut portion 109a in the intermediate film 109 as in the present embodiment, even if the intermediate film 109 is deformed by the rotation of the developing roller 59 and the supply roller 58, the intermediate film 109 is not broken. .

Next, as shown in FIG. 12, a side edge seal 110 is attached to the upper part of the intermediate layer film 109 using a double-sided tape. This side edge seal 110
Is formed of a sponge, and prevents a gap from being formed between a sheet metal of a layer thickness regulating blade 64 described later and the intermediate layer film 109, thereby preventing toner leakage.

Next, as shown in FIG. 13A, a support portion 64 made of iron or stainless steel of the layer thickness regulating blade 64 is provided.
The back-side blade side seal 111 is attached to the sheet metal 64b made of phosphor bronze or stainless steel attached to c with a double-sided tape. Here, the surface on the side where the pressure contact member 64a is provided is the front surface of the sheet metal 64b, and the opposite surface is the back surface of the sheet metal 64b. Back side blade side seal 1 along the longitudinal direction of layer thickness regulating blade 64
11 is formed to be wider than the distance W2 from the side end of the sheet metal 64b to the side end of the press-contact member 64a, and extends from the side end of the sheet metal 64b to the end of the press-contact member 64a. It covers up to the corresponding position. When the thickness regulating blade 64 is attached to the case 51, the sheet metal 64b receives a pressing force from the upper side seal 107 and the back side blade side seal 111 as shown in FIG. By providing the blade side seal 111 in the above-described region, not only the sheet metal 64b but also the end of the pressing member 64a is pressed, and the sheet metal 64b is not bent. Therefore, toner leakage due to bending of the sheet metal 64b can be prevented. Also,
The longitudinal length H1 of the back side blade side seal 111 along the width direction of the layer thickness regulating blade 64 is the sheet metal 64
b is a length that covers the entire area of the sheet metal 64b in the lateral direction. The double-sided tape is attached to the back surface of the back-side blade side seal 111, and the front surface is pressed against and contacts the upper side seal 107 as shown in FIG. Since the back side blade side seal 111 is formed of a soft urethane sponge, the contact portion between the back side blade side seal 111 and the upper side seal 107 is a sponge-to-sponge contact portion. Also,
The lower end surface of the back side blade side seal 111 is shown in FIG.
As shown in (C), it is in contact with the side edge seal 106. Accordingly, the contact portion between the back side blade side seal 111 and the side edge seal 106 is also a contact portion between sponges. As described above, the boundary portion between the back side blade side seal 111 and other members is a contact portion between the sponge and the sponge except for the adhesive surface with the sheet metal 64b, thereby reliably preventing toner leakage.

On the other hand, on the front side of the sheet metal 64b where the pressure contact member 64a is provided, a front blade side seal 112 as shown in FIG. It is attached by. The front blade side seal 112 is formed of a soft urethane sponge. Teflon felt, which will be described later, is mounted on the front blade side seal 112. The thickness when the front blade side seal 112 and Teflon felt are combined is as shown in FIG.
As shown in FIG. 7, the thickness is made larger than the pressure contact member 64a in consideration of a certain amount of crushing. With this configuration, even when the pressing member 64a is worn, the pressing force of the pressing members 64a at both ends on the developing roller 59 is not changed, and the toner from the pressing member between the pressing member 64a and the developing roller 59 is not changed. Leakage can be reliably prevented.

Next, as shown in FIGS. 14A, 14B and 14C, the Teflon felt 113 constituting the uppermost layer of the developer leakage preventing member at both ends is attached to the sheet metal 64b of the layer thickness regulating blade 64. , Front-side blade side seal 112, intermediate layer film 109, and side-side seal mounting area 100
Using double-sided tape. On the layer thickness regulating blade 64, as shown in FIGS. 14 (B) and 14 (C), the tip of Teflon felt is adhered to the sheet metal 64b, and the subsequent portion covers the front-side blade side seal 112. Make the attachment. With this configuration, the pressing member 6 of the layer thickness regulating blade 64
4a can be reliably prevented from leaking from both ends. Further, since the Teflon felt 113 moves together with the movement of the sheet metal 64b of the layer thickness regulating blade 64, the movement of the sheet metal 64b of the layer thickness regulating blade 64 is not hindered while reliably preventing toner leakage. Also,
Since the Teflon felt 113 has a low frictional resistance to the developing roller 59, the rotational torque of the developing roller 59 can be reduced.

In particular, in the present embodiment, the intermediate film 109 is attached to the back side of the Teflon felt 113, and the end of the intermediate film 109 is protruded toward the center in the longitudinal direction of the case 51. Therefore, even if a large amount of toner is supplied to the pressure contact portion between the supply roller 58 and the developing roller 59 and the toner density increases, the toner is blocked by the intermediate layer film 109 and the Teflon felt 11
The amount of toner that reaches the surface of the third roller rubbed with the developing roller 59 is significantly reduced. Therefore, the toner does not enter between the Teflon felt 113 and the developing roller 59, and the leakage of the toner is reliably prevented.

Next, FIG. 15A, FIG. 16A,
As shown in (B), a lower film 114 as a lower end developer leakage prevention member is attached. Lower film 11
4 is a PET sheet or a urethane rubber film. In this embodiment, a PET sheet is used. The lower film 114 is, as shown by oblique lines in FIG.
A part of the lower seal mounting area 101, a part of the front edge 51 d of the case 51, and a part of the lower side seal 105 are attached using a double-sided tape. in this way,
Since the adhesive surface of the lower film 114 includes not only the lower seal mounting area 101 but also the area of the width W3 and the height H2 of the front edge 51d, it is difficult to peel off. Accordingly, even when the pressing force between the developing roller 59, the lower film 114 and the Teflon felt 113 is increased to some extent, the peeling of the lower film 114 can be reliably prevented. Also, both ends of the lower film 114 are as shown in FIG.
As shown in FIG. 16 (B) and FIG. 16 (A), the user rides on the Teflon felt 113. With this configuration, when the developing roller 59 is mounted, the lower film 114 is pressed toward the Teflon felt 113 by the developing roller 59, and the gap between the Teflon felt 113 and the lower film 114 is eliminated.
It is possible to reliably prevent toner from leaking from the contact portion between the Teflon felt 113 and the lower film 114.

As described above, in the developing device 50 of the present embodiment, toner leakage from the upper portion, both ends, and the lower portion of the developing roller 59 can be reliably prevented.
Particularly, since the intermediate layer film 109 is attached to the back side of the Teflon felt 113 and the end of the intermediate layer film 109 is projected toward the center in the longitudinal direction of the case 51, the Teflon felt 113 of the toner and the developing roller 59
Can be reliably prevented from entering the rubbing portion, and toner leakage from the rubbing portion can be reliably prevented. When a polymerized toner having a fine particle diameter and high fluidity is used as in the present embodiment, it is possible to reliably prevent toner leakage, which is extremely effective.

As a result, the pressing force of the side seal 104 and the Teflon felt 113 against the developing roller 59 does not need to be increased more than necessary, so that the load on the motor can be reduced.

In the present embodiment, the amount of protrusion of the end of the intermediate layer film 109 was changed with reference to the side end surface of the side seal 104, and the difference in the effect of preventing toner leakage was confirmed by experiments. As a result, when the amount of protrusion was less than 1 mm from the side end surface of the side seal 104, the effect of preventing toner leakage was low, and slight toner leakage occurred.
On the other hand, when the protrusion exceeds 4 mm, the convection of the toner is remarkably deteriorated toward the end of the protrusion, the deterioration of the toner is promoted, and print fogging occurs at the end of the sheet. From these results, it was found that the length of the protruding portion of the intermediate layer film 109 is preferably 1 mm or more and 4 mm or less based on the side end surface of the side seal 104. In particular, it was confirmed that 3 mm was optimal.

When the relationship with the maximum print width (paper width) was examined, the protrusion at the end of the intermediate layer film 109 was found to be:
It was found that a length that does not enter the maximum print width (paper width) area is appropriate. When the protruding portion at the end of the intermediate layer film 109 entered the maximum printing width (paper width) region, a printing defect was confirmed.

Further, in this embodiment, an example in which a resin sheet is used as the material of the intermediate layer film 109 has been described. However, since the resin sheet has an appropriate hardness, the rigidity of the resin sheet itself is reduced. Thus, while maintaining the flatness of the toner blocking portion to some extent, an effect is obtained that the toner blocking portion is appropriately deformed and is easily assembled.

In the present invention, the intermediate film 109 is not limited to a resin sheet, but may be a urethane sheet or Teflon felt.

Further, in the above-described embodiment, an example is described in which the developer leakage preventing members at both ends have a two-layer structure of a side seal and Teflon felt, and an intermediate layer film as a sheet-like member is provided on the intermediate layer. However, the present invention is not limited to this.When the developer leakage preventing members on both ends have a single-layer structure in which the side seal is attached to the developing device housing, the developing device housing and the side seal What is necessary is just to provide a sheet-like member between them.

Further, the length of the supply roller is set to such a length that the side end surface of the supply roller rubs against the side end surface of the side seal. However, the present invention is not limited to this. The length may be such that there is a gap between the end face and the side end face of the side seal. Also in this case, the sheet-like member reduces the toner density in the rubbing portion between the Teflon felt and the developing roller and in the vicinity thereof, thereby reliably preventing toner leakage.

In the above description, the developing device 5
0 has been described as an example in which the drum cartridge 2a is detachably attached to the image forming apparatus main body. However, the present invention is not limited to this. The drum cartridge 2a and the developing device 50 may be detachably attached to the image forming apparatus. It may be configured. Further, the developing device 50 does not necessarily need to be detachable from the image forming apparatus, and may be a stationary type. If the present invention is applied to a developing device cartridge or a process cartridge, there is an effect that toner leakage at the time of attachment / detachment can be surely prevented. The effect of not contaminating can be exerted.

As described above, the present invention has been described based on the embodiments. However, the present invention is not limited to the above embodiments, and various improvements and modifications can be made without departing from the spirit of the present invention. Can easily be inferred.

[0085]

According to the first aspect of the present invention, both ends of the developing device housing are developed so as to rub against the peripheral surfaces of both ends of the developer carrier near both ends in the longitudinal direction of the developing device housing. A developer leakage prevention member is provided, and a rubbing between the both ends developer leakage prevention member and the developer carrying member is provided at a rear position of a sliding surface of the both ends developer leakage preventing member and the developer carrying member. Since the sheet-shaped member that covers the boundary and the periphery of the rubbing boundary is provided, and the sheet-shaped member is protruded from the rear surface position toward the center in the longitudinal direction of the developing device housing opening,
The developer density at the rubbing boundary portion and the periphery thereof is reduced, and the intrusion of the developer into the rubbing portion between the developer leakage preventing member and the developer carrier at both ends is prevented, and the developer from the rubbing portion is reduced. Leakage can be reliably prevented. Also, as a result,
Since the pressing force of the developer leakage prevention members at both ends against the developer carrier can be suppressed, the load on the motor can be reduced.

According to the developing device of the present invention, the developer leakage preventing members at both ends are provided with a base member attached to the developing device housing and the developer carrier attached on the base member. Since the sheet-shaped member is sandwiched between the base portion and the rubbing portion,
To reduce the developer density at and around the rubbing boundary of the rubbing portion, to prevent the developer from entering between the rubbing portion and the developer carrying member, and to reliably prevent developer leakage. Can be.

According to a third aspect of the present invention, there is provided a developer made of a foamed elastic material which is rotatably disposed while rubbing against the developer carrier, and conveys and supplies the developer to the developer carrier. The image forming apparatus further includes a transport supply body, and the projecting portion of the sheet-shaped member is sandwiched between the developer carrier and the developer transport supply body. To reduce the developer density at the rubbing boundary portion and the periphery thereof to prevent the developer from entering the rubbing portion between the developer leakage prevention member and the developer carrier at both ends, thereby preventing the developer from entering the rubbing portion. Developer leakage can be reliably prevented.

According to the fourth aspect of the present invention, since the sheet-like member is formed of a resin, the sheet-like member has an appropriate hardness, can reliably prevent the developer from entering, and can appropriately deform. Therefore, it can be easily attached in a shape along the peripheral surface of the developer carrying member.

According to the fifth aspect of the present invention, since the sheet-like member is formed of PET, the sheet-like member has appropriate hardness, can surely prevent the developer from entering, and can appropriately deform. Therefore, it can be easily attached in a shape along the peripheral surface of the developer carrying member.

According to the sixth aspect of the present invention, since the sheet-shaped member is provided with a cut along the longitudinal direction of the developer carrier, even if a load accompanying rotation of the developer carrier is applied. Thus, the sheet-like member itself can be reliably prevented from being broken.

According to the seventh aspect of the present invention, the sheet-like portion is positioned in the longitudinal direction of the opening of the developing device housing with respect to the sliding boundary between the developer leakage preventing member and the developer carrier at both ends. Since the protrusion protrudes toward the center and the length of the protruding portion along the longitudinal direction is 1 mm or more, the amount of developer exceeding the protruding portion can be reduced to prevent developer leakage.
In addition, the length of the protruding portion along the longitudinal direction is 4
mm or less, so near the tip of the protruding portion,
It is possible to prevent toner deterioration without deteriorating the convection of the developer.

According to the developing device of the present invention, since the polymerized toner produced by the polymerization method is used as the developer, the fluidity is high and the developer easily leaks. Since the developer member reduces the developer density at the rubbing boundary between the developer leakage preventing member and the developer carrier at both ends and the periphery thereof, toner leakage can be reliably prevented.

According to the process cartridge of the ninth aspect, the process cartridge detachably formed in the image forming apparatus is provided with the developing device of any one of the first to eighth aspects. Even when the cartridge is attached or detached, the developer can be reliably prevented from leaking. Therefore, an easy-to-use process cartridge can be provided.

According to the tenth aspect of the present invention, the developing device according to any one of the first to eighth aspects is formed detachably with respect to the image forming apparatus or the process cartridge. Also, it is possible to reliably prevent the developer from leaking even when attaching or detaching. Therefore, an easy-to-use developing device cartridge can be provided.

According to the image forming apparatus of the eleventh aspect,
Since the developing device according to any one of claims 1 to 8, the process cartridge according to claim 9, or the developing device cartridge according to claim 10 is provided, the developer does not leak and the inside of the image forming apparatus main body is not generated. Developer contamination can be reliably prevented. Therefore, it is possible to form a high-quality image free from printing stains.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a schematic configuration of an image forming apparatus according to an embodiment of the present invention.

2 (A) is a partially cutaway perspective view showing a seal portion of a developing device case before a seal member is attached, and FIG. 2 (B) is the seal seen from the direction of arrow B shown in FIG. 2 (A). It is a figure which shows a part.

3 (A) is a partially cutaway perspective view showing a seal portion of a developing device case when a side edge seal is attached, and FIG. 3 (B) is a cross-sectional view taken along line CC of FIG. 3 (A). , FIG.
FIG. 4C is a view showing the seal portion viewed from the direction of arrow B shown in FIG.

4 (A) is a partially cutaway perspective view showing a seal portion of a developing device case when an upper side seal attaching film is attached, and FIG. 4 (B) is an arrow A shown in FIG. 4 (A); FIG. 4C is a view showing the seal portion viewed from the direction, and FIG.
It is a figure showing the seal part concerned seen from the arrow B direction shown to (A).

5A is a partially cutaway perspective view showing a seal portion of a developing device case when a side seal is attached, FIG.
FIG. 5B is a diagram showing the seal portion as viewed from the direction of arrow B shown in FIG.

FIG. 6A is a partially broken perspective view showing a seal portion of a developing device case when a lower side seal is attached,
FIG. 6B is a diagram showing the seal portion as viewed from the direction of arrow B shown in FIG. 6A.

7A is a partially cutaway perspective view showing a seal portion of a developing device case when an edge seal is attached, FIG.
FIG. 8B is a diagram showing the seal portion as viewed from the direction of arrow B shown in FIG.

FIG. 8A is a partially broken perspective view showing a seal portion of a developing device case when an upper side seal is attached;
FIG. 8B is a diagram showing the seal portion viewed from the direction of arrow A shown in FIG. 8A, and FIG. 8C is a diagram showing the seal portion viewed from the direction of arrow B shown in FIG. It is.

FIG. 9 is a front view showing a seal portion of the developing device case when an upper seal is attached.

FIG. 10 is a view showing a seal portion viewed from the direction of arrow B shown in FIG. 9;

11 (A) is a partially cutaway perspective view showing a seal portion of a developing device case when an intermediate layer film is attached, and FIG. 11 (B) is viewed from an arrow B direction shown in FIG. 11 (A). FIG. 3 is a diagram showing the seal portion.

FIG. 12 is a partially cutaway perspective view showing a seal portion of the developing device case when a side edge seal is attached.

13 (A) is a diagram of the layer thickness regulating blade viewed from the back side, FIG. 13 (B) is a diagram of the layer thickness regulating blade viewed from the front side, and FIG. 13 (C) is a diagram of FIG. 11 (B). It is a figure showing the seal part seen from the arrow B direction similarly.

14A is a partially cutaway perspective view showing a seal portion of a developing device case when Teflon felt is attached, and FIG. 14B is viewed from the direction of arrow A shown in FIG. 14A. FIG. 14C is a diagram showing the seal portion, and FIG. 14C is a diagram showing the seal portion viewed from the direction of arrow B shown in FIG.
FIG. 14D is a sectional view taken along line DD of FIG.

FIG. 15A is a plan view showing a lower film and the vicinity of a mounting portion thereof, and FIG. 15B is a diagram showing an adhesive surface of the lower film.

16 (A) is a partially cutaway perspective view showing a seal portion of a case 51 on the opposite side to FIG. 14 (A) when a lower film is attached, and FIG. 16 (B) is FIG. 14 (C). FIG. 7 is a view showing the seal portion as viewed from the direction of arrow B as in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Laser beam printer 50 Developing device 51 Case 52 Toner accommodating chamber 59 Developing roller 64 Layer thickness regulating blade 64a Press-contact member 64b Sheet metal 100 Side seal mounting area 101 Lower seal mounting area 102 Side edge seal 103 Upper side seal mounting film 104 Side seal 105 Lower side seal 106 Edge seal 107 Upper side seal 108 Upper seal 109 Intermediate layer film 109a Cut portion 110 Side edge seal 111 Back side blade side seal 112 Front side blade side seal / 113 Teflon felt 114 Lower film

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[Procedure amendment]

[Submission Date] June 25, 1999 (1999.6.2
5)

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] FIG.

[Correction method] Change

[Correction contents]

FIG.

Claims (11)

[Claims] A developer carrier is rotatably disposed in an opening of a developing device housing for accommodating a developer, and a thin layer of the developer formed on the developer carrier is formed into an electrostatic latent image. A developing device that forms a visible image by facing each other, and is provided near both ends in the longitudinal direction of the opening of the developing device housing so as to rub against the peripheral surfaces on both ends of the developer carrier. Both ends developer leakage prevention member, provided at a position on the back side of the rubbing surface of the both ends developer leakage prevention member and the developer carrier, the both ends developer leakage prevention member and the developer carrier And a sheet-like member that covers the periphery of the rubbing boundary, wherein the sheet-like member protrudes from the back position toward the center in the longitudinal direction of the developing device housing opening. A developing device, which is provided. 2. The developing device according to claim 1, wherein the developer leakage preventing member includes a base member attached to the developing device housing, and a rubbing portion mounted on the base member and rubbing the developer carrier. The developing device according to claim 1, wherein the sheet-shaped member is sandwiched between the base portion and the rubbing portion. 3. A developer transport supply member made of a foamed elastic material, which is rotatably disposed while rubbing against the developer carrier, and further supplies the developer to the developer carrier. The developing device according to claim 1, wherein a protruding portion of the member is sandwiched between the developer carrying member and the developer carrying / supplying member. 4. The developing device according to claim 1, wherein said sheet-like member is formed of a resin. 5. The developing device according to claim 4, wherein said sheet-like member is formed of PET. 6. The developing device according to claim 1, wherein the sheet-shaped member is provided with a notch along a longitudinal direction of the developer carrier. 7. The sheet-like member protrudes toward the center in the longitudinal direction of the opening of the housing of the developing device, beyond a rubbing boundary between the developer leakage preventing member and the developer carrying member at both ends. The length of the portion along the longitudinal direction is 1 mm or more and 4 mm
The developing device according to claim 1, wherein: 8. The developing device according to claim 1, wherein the developer is a polymerized toner produced by a polymerization method. 9. A process cartridge detachably formed in an image forming apparatus, comprising: a carrier for the electrostatic latent image; and a developing device according to claim 1. A process cartridge characterized by the above-mentioned. 10. A developing device cartridge, wherein the developing device according to claim 1 is detachably mounted on an image forming apparatus or a process cartridge. 11. An image forming apparatus comprising the developing device according to claim 1, a process cartridge according to claim 9, or a developing device cartridge according to claim 10.