JP3242557B2 - Developing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device used for an image forming apparatus such as a copying machine, a laser beam printer, and a facsimile.

[0002]

2. Description of the Related Art Generally, in an image forming apparatus such as an electrophotographic copying apparatus and an electrostatic information recording apparatus, development for visualizing a latent image on a latent image carrier (hereinafter referred to as "photosensitive drum") is performed. The device is installed. The developing device includes: a developer container containing a developer; a developer carrier that carries the developer toward the latent image carrier while supporting the developer in the developer container; Body (hereinafter referred to as "developing sleeve")
A developer regulating member (hereinafter, referred to as “developing blade”) for regulating the thickness of the coat layer of the developer (hereinafter, referred to as “toner”).

In such a developing device, the prevention of toner leakage at both ends in the axial direction of the developing sleeve at the opening on the side facing the photosensitive drum has conventionally been achieved by preventing the peripheral surface of the developing sleeve from facing the photosensitive drum. A flexible developer leakage preventing member made of a felt flocked material or the like is provided at a portion opposite to a side where the peripheral surface of the developing sleeve is opposed to the photosensitive drum at both ends in the axial direction of the developing blade that is in contact with the developing blade. (Hereinafter referred to as a “developing end seal”) is brought into contact with the peripheral surface of the developing sleeve.

The developing end seal is attached to a wall provided on a part of the frame of the developing device so as to have a certain gap with the peripheral surface of the developing sleeve. Is set smaller than the gap. Therefore, the developing end seal is compressed between the developing sleeve and the wall surface of the developing end seal (the bearing surface to which the developing end seal is attached), thereby preventing leakage of toner.

[0005]

According to the above-mentioned conventional measures for preventing leakage of toner, when the developing blade is a rigid body, the developing end seals are attached to both ends of the developing blade in the axial direction by mounting. A gap between the two can be eliminated.

However, recently, in order to improve the image quality with high accuracy, the developing blade is mainly made of an elastic body having flexibility. When the developing blade is an elastic body, even if the developing end seal is attached to the end of the developing blade while being abutted, the developing blade is elastically deformed and the abutting amount is not constant. In some cases, the abutting pressure of the portion on the developing sleeve changes, resulting in an image defect. In addition, the dimensional accuracy of the components of the developing device such as the developing blade must be increased more than necessary, and there are disadvantages that the mass productivity and manufacturability of the developing device are poor and the price is high. Therefore, although not preferable, at present, a gap is set between both ends of the elastic blade and the developing end seal.

However, recently, from the viewpoint of ecology, it has become necessary to improve the sealing property of the developing device against toner leakage in order to extend the life of the developing device. However, as described above, at present, there is a gap between the developing blade and the developing end seal, and the thickness of the toner coat layer on the developing sleeve in this portion is larger than in other portions. Therefore, the amount of toner entering the gap at the developing end seal increases, and when the developing device is used for a long time, the toner leaks from the gap and adversely affects the image. there were.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a developing device capable of preventing toner from leaking at the end of a developing blade, which is provided in the above-described conventional device.

[0009]

According to the present invention, an object of the present invention is to provide a developing device for developing a latent image on an image carrier.
Is rotatably supported to the frame at least apparatus, a developer carrying member for carrying a developer for developing said latent image to a development zone you close to the image bearing member, the developer carrying member A developer regulating member for regulating the thickness of the developer layer on the peripheral surface of the developer carrying member by contacting the peripheral surface with a region extending in the axial direction of the developer carrying member; developing
The frame and the peripheral surface of the developer carrying member outside the developer regulating member
A first elastic seal member for sealing between
A second resilient seal member for preventing developer leakage from member and the contact with the developer carrying member peripheral surface and the frame developer carrying member circumferential surface between the first elastic sealing member, said second has the a seat surface provided in a part of the frame for attachment to the elastic seal member a predetermined position, and the said seat surface for some of the developer carrying member of the second elastic sealing member This is achieved by forming a convex-shaped portion which is pressed to make contact with a constant contact pressure.

[0010]

According to the present invention, the shaft of the developer regulating member is provided.
First elastic seal members are provided at both ends in the direction to seal the gap between the developer regulating member and the inner wall of the developing device.
A part of the second elastic seal member is brought into contact with the developer carrier at a constant pressure by a convex part formed on a part of the seating surface, so that the toner coat near the inner wall of the developing device is formed. The layer is scraped off, and the intrusion of toner at both ends of the developer regulating member is minimized, the sealing property of the developing device is improved, and the life of the developing device is extended.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to FIGS. 1 to 8 of the accompanying drawings.

First, the overall configuration of the image forming apparatus A and the process cartridge B in FIG. 1 will be described, and then the toner leakage preventing means in the developing device of the process cartridge will be described.

FIG. 1 is an explanatory view of the structure of an image forming apparatus having a process cartridge mounted thereon, FIG. 2 is a perspective view of the image forming apparatus, and FIG. 3 is an explanatory view of the structure of the process cartridge.
FIG. 4 is an explanatory perspective view, and FIGS. 5 and 6 are explanatory views of a mounting configuration of a process cartridge.

As shown in FIGS. 1 and 2, the image forming apparatus A scans light from a laser light source emitted according to image information with a rotating polygon mirror 1a.
It has an optical unit 1 for irradiating through a lens 1b and a reflecting mirror 1c, and irradiates a light image based on image information to a photosensitive drum 7 as an image carrier from the optical unit 1 to form a toner image.

In synchronization with the formation of the toner image, the recording medium 2 is transferred from the cassette 3a to the pickup rollers 3b,
In the image forming section which is reversely conveyed by the conveying means 3 including the conveying roller pairs 3c and 3d, the registration roller pair 3e, and the like, and formed into a cartridge as the process cartridge B, the toner image formed on the photosensitive drum 7 is transferred as the transferring means. The image is transferred to the recording medium 2 by applying a voltage to the transfer roller 4.

Further, a fixing roller 5b having a built-in heater 5a while guiding the recording medium 2 after the transfer of the toner image with a guide member 3f, and a driving roller 5c for pressing the recording medium 2 to the roller 5b to convey it. Conveyed to means 5,
The transfer toner image is fixed on the recording medium 2.

The recording medium 2 is discharged to a discharge roller pair 3
g, 3h, and 3i, and is configured to be discharged to the discharge unit 6 through the reverse transfer path 3j. As for the discharge, the swingable flapper 3k may be operated, and the discharge may be performed linearly by the discharge roller pair 3m without passing through the reverse conveyance path 3j.

On the other hand, as shown in FIGS. 3 and 4, the process cartridge B constituting the image forming section rotates a photosensitive drum 7 having a photosensitive layer and transfers the surface of the photosensitive drum 7 to a charging roller 8 as charging means. Charged uniformly by applying voltage,
The light image from the optical unit 1 is exposed to a photosensitive drum 7 through an exposure unit to form a latent image, and a developing unit 9 serving as a developing device is formed.
It is constituted so that it may develop.

The developing means 9 sends out the toner in the toner container by a toner sending member 9a, rotates a developing sleeve 9b containing a fixed magnet therein,
A toner layer provided with a triboelectric charge by c is formed on the surface of the developing sleeve 9b, and the toner is transferred to the photosensitive drum 7 in accordance with the latent image to form a toner image and visualize the toner image.

After applying a voltage having a polarity opposite to that of the toner image to the transfer roller 4 to transfer the toner image onto the recording medium 2, the photosensitive drum 7 is moved by the cleaning blade 10a.
Scraping off the residual toner and collecting waste toner 1
The residual toner on the photosensitive drum 7 is removed by the cleaning means 10 for collecting the toner on the photosensitive drum 7.

An antenna line 17 for detecting the residual toner at a position separated from the developing sleeve 9b by a predetermined distance.
Is provided. The antenna wire 17 and the developing sleeve 9b
The capacitance between the two varies depending on the amount of toner existing between them, and the change in the capacitance is detected as a change in potential difference, thereby detecting the remaining amount of toner.

The components such as the photosensitive drum 7 are connected to a toner frame 11 for storing toner and a developing frame 12 for holding a developing member such as a developing sleeve 9b. The process cartridge B is housed in a housing formed by connecting a cleaning frame 13 holding the blade 10a and the like to form a cartridge, and the process cartridge B is removably mounted to a cartridge mounting means provided in the apparatus main body 14. .

As means for mounting the cartridge, when the opening / closing member 15 is opened, a cartridge mounting space is provided as shown in FIGS. 5 and 6, and a cartridge mounting guide member G1 is provided on the left and right inner side surfaces of the apparatus main body 14. A guide portion G2 for inserting the process cartridge B is provided facing the left and right guide member G1. The process cartridge B is inserted into the guide portion G2 along the drum centering axis of the process cartridge B, and the opening / closing member 15 is closed to attach the process cartridge B to the image forming apparatus A. Note that the process cartridge B
The cartridge B is provided with a handle recess 16 as shown in FIG.

On the other hand, the developing blade 9c abutting on the developing sleeve 9b is formed by attaching a blade obtained by cutting a flexible material such as polyurethane rubber or silicon rubber into a plate shape to a supporting member 9d such as a sheet metal. developing blade 9c are positioned and fixed by accurately screw 9d ₁ the mounting seat surface of the frame 12 of the developing device the supporting member 9d to rubs the developing sleeve 9b with a predetermined contact pressure.

Next, a configuration for preventing toner leakage of the developing device 9 will be described. As shown in FIG. 8, the developing blade 9c
At both ends of the development end seal S ₁ to form one of the elastic seal member are arranged. In the present example, the elastic seal member is made as a separate member from the side seal to be described later and the development end seal S _1, may be formed as a single member it is not limited to this in the present invention. The development end seal S ₁ is found on the semicircular to the housing of the frame 12 (not shown) as shown in FIG. 7, the developing sleeve 9b
It is configured to cover. This developing end seal S ₁
It is formed from a rectangular plate made of a flocked material such as wool felt or a flexible material such as urethane foam rubber. By compressing this seal by a certain amount (in this embodiment,
A seal member having a thickness of 2.65 mm is crushed to 2.0 mm. ) Sealing property is ensured.

[0026] However, as described above, a gap d is formed between the development end seal S ₁ to the end that is attached to the developing frame body wall of the developing blade 9c, the toner of this part The coat layer becomes thicker than other portions. Therefore, in this state, the developing end seal S ₁
Intrusion amount of the toner becomes much, if you try to use a developing device with longer service life, from the development end seal S _1, toner leaks to the outside from the developing device 9, adversely affected the image.

[0027] Therefore, in this embodiment, by disposing the side seals S ₂ as another member forming the elastic sealing member 8 on the inside of the development end seal S ₁ (axially inner) The gap d is sealed. Also, sticking seat surface of the side seal S _2, as shown in FIG. 7 are convex portion S ₂₁ is provided, the developing sleeve 9b near the tip portion of the side seal S ₂ is pressed by the convex portion S ₂₁ , So that the toner layer on the developing sleeve 9b is scraped off.

By adopting the configuration of the elastic seal member having the side seal S ₂ and the developing end seal S ₁ , it is possible to scrape the toner coat layer in the gap d to the minimum necessary. toner from entering the S ₁ is being depleted.

[0029] Therefore, developing apparatus is characterized by having a sealing structure of this embodiment, since the margin is greatly increased with respect to the toner of the development end seal S ₁ as compared with the conventional developing device, long life Becomes possible.

[0030]

As described above, according to the present invention,
Seal the gap between the peripheral surface of the developer carrier and the frame at the outside in the axial direction
A first elastic seal member , a developer regulating member, and a first elastic member;
The frame contacts the peripheral surface of the developer carrying member between the seal members.
To prevent the developer from leaking from the developer and the peripheral surface of the developer carrier
Elasticity and sealing member is provided, on a seat surface formed on the frame member to form a convex portion said second elastic sealing members of certain
The Rukoto brought into contact with contact pressure, because the amount of intrusion toner by scraping up closer end toner required minimum of the developing blade is greatly reduced, it is possible to extend the life of the developing device, and the Since the protruding portions are easily formed, such a long-life developing device can be provided by an inexpensive method.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram illustrating a configuration of an image forming apparatus equipped with a process cartridge according to an embodiment of the present invention.

FIG. 2 is an explanatory perspective view of the image forming apparatus of FIG. 1;

FIG. 3 is an explanatory diagram of a configuration of the process cartridge of FIG. 1;

FIG. 4 is an explanatory perspective view of the process cartridge of FIG. 3;

FIG. 5 is an explanatory diagram of an inner surface on a non-driving side of the image forming apparatus in which the process cartridge of FIG. 1 is mounted.

FIG. 6 is an explanatory diagram of an inner surface on a driving side of the image forming apparatus in which the process cartridge of FIG. 1 is mounted.

FIG. 7 is a cross-sectional view of the developing device according to the embodiment of the present invention.

8 is a view showing the arrangement of the developing sleeve, the developing blade, the developing end seal, and the side seal in FIG. 7 in the longitudinal direction.

[Explanation of symbols]

9 developing device 9b developer carrying member (developing sleeve) 9c developer regulating member (developing blade) 12 frame (frame) S ₁ elastic sealing member (development end seal) S ₂ elastic sealing member (side seal)

Continuation of the front page (56) References JP-A-3-15876 (JP, A) JP-A-4-249273 (JP, A) JP-A-5-341636 (JP, A) JP-A-2-301784 (JP) , A) Hikaru Hei 2-1759 (JP, U) (58) Fields surveyed (Int. Cl. ⁷ , DB name) G03G 13/08-13/095 G03G 15/08-15/095

Claims (1)

(57) [Claims] 1. A developing device for developing a latent image on an image carrier, wherein the developing device is rotatably supported by at least a frame of the device.
A developer for developing the latent image is brought close to the image carrier.
A developer carrying member for carrying the developing zone you, the developer layer of the developer carrying member peripheral surface in contact with a region extending in the axial direction of the developer carrying member with respect to the peripheral surface of said developer carrying member A developer regulating member for regulating the thickness and an axial direction of the developer carrying member;
The frame and the developer carrying member are provided outside the developer regulating member.
A first elastic sealing member for sealing between the holding member and a peripheral surface thereof;
A second resilient seal member for preventing developer leakage from the contact with the developer carrying member peripheral surface and the frame developer carrying member circumferential surface between the image-regulating member and the first elastic sealing member, the second
Has the a seat surface provided in a part of the frame for attachment to the elastic seal member a predetermined position, and the said seat surface developer part of the second <br/> elastic sealing member A developing device, wherein a convex portion is formed to press the carrier so as to contact the carrier with a constant contact pressure.