JP2003043808A - Developing device, process cartridge and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent toner from being leaked and scattered from the end of a developing roller 12 in a longitudinal direction in a developing device which can be attached to/detached from an electrophotographic image forming device. SOLUTION: This developing device is provided with the developing roller 12 carrying and feeding the toner for developing an electrostatic latent image on an image carrier, a developing blade 16 regulating the layer thickness of the toner on the roller 12, and end sealing members 32a and 32b preventing the toner from being leaked from the end of the roller 12 in the longitudinal direction. The edge 102b3 of the blade 16 on the side of the developing roller abutting part is formed in obliquely cut shape in an area where the blade 16 is pressed to the roller 12 by the members 32a and 32b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser printer,
The present invention relates to an electrophotographic image forming apparatus such as a copying machine or a facsimile machine, and more particularly to a developing device used in the image forming apparatus, and a process cartridge including the developing device.

[0002]

2. Description of the Related Art Conventionally, in an image forming apparatus using an electrophotographic image forming process, a photosensitive drum, which is one form of an electrophotographic photosensitive member as an image carrier, and a process means acting on the photosensitive drum. A process cartridge system is adopted in which the cartridges are integrated into a cartridge and the cartridge can be attached to and detached from the main body of the image forming apparatus. According to the process cartridge system, the maintenance of the apparatus can be performed by the user himself without resorting to a serviceman, so that the operability can be markedly improved. Therefore, the process cartridge is widely used in image forming apparatuses.

When the life of the photosensitive drum is extended and the number of printable sheets is increased, the developing means for limiting the toner (developer) supply capacity is an independent unit and the latent image on the photosensitive drum is developed. Cartridge (developing device) in which a toner frame containing toner and toner are integrated
And a process cartridge that integrates a photosensitive drum, a charging unit, and a cleaning unit into one unit, which facilitates attachment / detachment to / from the main body of the apparatus and maintenance, and can be used according to the life of each main component. Is coming.

In the developing cartridge, a developing roller as a developer carrying member carrying toner and developing the toner on the photosensitive drum, and a developing blade as a developer regulating member for regulating the thickness of the toner coated on the developing roller. And a toner applying roller for applying toner to the developing roller, and the developing frame supporting the above and the toner frame are combined to form a cartridge frame (developing container), thereby reducing the size of the developing cartridge. .

Some of the developing blades are made of rectangular thin sheet metal or the like, and contact the developing roller at the edge or surface on the free end side to uniformly regulate the thickness of the toner coated on the developing roller.

Further, at the end of the opening of the cartridge frame, in order to prevent the toner from leaking out from the gaps respectively formed between the cartridge frame and the developing blade and the developing roller, a foamed elastic body, felt, velvet, etc. An end seal member composed of is disposed. further,
Conventionally, the developing blade and the end seal member were arranged with a slight gap, but with the decrease in the toner diameter, leakage from this gap cannot be ignored, and the developing blade is arranged at a position overlapping the end seal member. It became so. The end seal member is arranged on the rear side of the developing blade and the developing roller so as to cover the opening of the developing frame, and is pressed against the rear surfaces of the developing roller and the developing blade.

[0007]

However, the above-mentioned conventional techniques have the following problems. Since the end seal member presses the end portion of the developing blade against the developing roller, the abutting position of the developing blade on the developing roller changes in the vicinity thereof, and the toner layer on the developing roller in the area changes to other parts. It becomes thicker than the part. For this reason,
The toner in the thick toner layer at the end portion of the developing roller is not easily held on the developing roller, and is likely to leak or scatter due to centrifugal force or the like accompanying the rotation of the developing roller.

An object of the present invention is to prevent leakage and scattering from the end portion of the developing roller with a simple structure so that the developing device, the process cartridge, and the image forming apparatus can keep the image at the same time without polluting the apparatus. Is to provide.

[0009]

A first structure for achieving the object of the present application is a developing container having an opening facing an image carrier and containing a developer, and an opening of the developing container. And a developing agent carrier which is rotatably supported by a carrier and which carries and conveys a developing agent for developing an electrostatic latent image on the image carrier, and the developing agent contacting the peripheral surface of the developing agent carrier, A developer regulating member for regulating the layer thickness of the developer on the developer carrying member, and a rear surface of the developer carrying member and the developer regulating member at the end of the opening of the developing container so as to cover the opening. Placed on the side,
An end portion that is pressed against the back surfaces of the developer bearing member and the developer regulating member to prevent the developer from leaking from the gaps respectively formed between the developer container and the developer bearing member and the developer regulating member. A seal member, and in the vicinity of a longitudinal end of the developer regulating member on the side of the developer bearing member abutting side, an edge of the developer regulating member on the developer bearing body side is separated from the developer bearing body. The developing device is configured to retract in a direction away from the developing device.

A second structure for achieving the object of the present application is to provide an edge of the developer regulating member on the side of the developer bearing member in the vicinity of an end portion of the developer regulating member on the contact side of the developer bearing member. The developing device according to the first configuration is characterized in that the developing device is gradually retracted toward the end in a direction away from the developer carrying member.

A third structure for achieving the object of the present application is the developing device according to the first or second structure, an image carrier developed by the developing device, and the image carrier is cleaned. A process cartridge comprising: a cleaning unit; and a charging unit that charges the image carrier.

A fourth configuration for achieving the object of the present application is an image forming apparatus including the developing device according to the first or second configuration.

A fifth configuration for achieving the object of the present application is an image forming apparatus including the process cartridge according to the third aspect.

[0014]

DETAILED DESCRIPTION OF THE INVENTION A developing device, a process cartridge and an image forming apparatus using the same according to the embodiments of the present invention will be described in detail below with reference to the drawings. The examples in the present embodiment do not limit the present invention.

(Embodiment 1) As a form of an image forming apparatus equipped with a developing device according to Embodiment 1, a color laser beam printer for forming a color image by an electrophotographic system is referred to FIGS. 1 to 6. And explain.
In addition, the same code | symbol is described in the member common to each figure.

[Overall Configuration of Image Forming Apparatus] The overall configuration of the color laser beam printer will be described below with reference to the longitudinal sectional view of the color laser beam printer shown in FIG.

In the color laser beam printer, the surface of the photosensitive drum 1 as an image bearing member which rotates counterclockwise in the drawing at a constant speed is uniformly charged by a charging roller 2 as a charging unit, and the exposing unit is exposed. Laser light corresponding to image information is irradiated from 3 to form a latent image on the photosensitive drum 1. Then, the latent image is developed for each color by four developing cartridges (developing devices) Dm, Dc, Dy, Db (collectively referred to as D) to form a developed image, and the developed image is formed on the photosensitive drum 1 in a belt form. Intermediate transfer unit 4
And transferred to form a color image. Then, this color image is transferred by the transfer roller 6 to the recording medium P (for example, recording paper, OHP sheet, etc.) conveyed by the conveying means 5 from the paper feeding cassette 5a, and the recording medium P is transferred.
Is conveyed to the fixing unit 7 to fix the color image, and the color image is discharged to the discharging unit 8 on the upper surface of the apparatus.

[Structure of Developing Cartridge] The overall structure of the developing cartridge D will be described below.

The four developing cartridges D are yellow,
A yellow developing cartridge Dy capable of developing magenta, cyan, and black colors, a magenta developing cartridge Dm, a cyan developing cartridge Dc, and a black developing cartridge Db form a full-color image.

The four developing cartridges D are shown in FIG.
As shown in FIG. 3, the rotary units 11 are detachably mounted to each other, and at the time of image formation, the rotary units 11 rotate about the rotary shaft 10 and face the photoconductor drums 1 with each developing cartridge D mounted. After the predetermined developing cartridge D is positioned at the predetermined position, a visible image is formed corresponding to the latent image on the photosensitive drum 1.

At the time of color image formation, 1 of the intermediate transfer member 4 is used.
The rotary unit 11 rotates once for each rotation, and the developing process is sequentially performed.

Next, the developing cartridge D will be described in detail with reference to FIGS. 2 and 3. 2 is a vertical cross-sectional view of the developing cartridge according to the first embodiment, and FIG. 3 is a perspective view of the developing cartridge according to the first embodiment with the shutter open.

2 and 3, the developing cartridge D
Is a developing member supporting frame 63A for supporting the developing member.
A toner frame 63B for containing toner, a cover frame 63C, side covers 63D and 63E, and a coupling frame 63F. These plural frames are combined to form a cartridge frame (developing container) 63. Further, an opening 63b is formed on the surface of the cartridge frame 63 facing the photosensitive drum 1, and the opening 63b is formed.
A shutter 64 for freely opening and closing b is provided.

FIG. 2 shows a state in which the developing cartridge D (for example, the yellow developing cartridge Dy) is positioned and stationary at a position facing the photosensitive drum 1. The developing cartridge D includes a developing roller 12 as a developer carrying member that supplies toner to the photosensitive drum 1, and a toner storage unit 6 that stores toner to be supplied to the developing roller 12.
3a. The developing roller 12 is supported by the cartridge frame 63 through the opening 63a. Further, a toner feeding member 15 is provided in the toner storage portion 63a.

Here, the toner feeding member 15 is rotated by receiving a driving force from the apparatus main body 30, and the toner in the toner storage portion 63a is fed to the developing roller 12. Developing roller 12
For example, a rubber layer 12b which is an elastic member is wound around a metal shaft 12a, and a developing blade 16 as a developer regulating member is pressed against the peripheral surface of the developing roller 12. Further, the developing member supporting frame 63A is the developing roller 1
A coating roller having a peripheral surface which is pressed against the peripheral surface of the developing roller 12 and moves in a direction opposite to the peripheral surface of the developing roller 12 is also rotatably provided. Therefore, when the developing roller 12 rotates in the clockwise direction in FIG. 4, a thin layer of toner is applied to the peripheral surface of the developing roller 12.

Then, the photosensitive drum 1 on which the latent image is formed.
By applying the developing bias supplied from the apparatus main body 30 to the developing roller 12 opposite to the above, toner development is performed on the photosensitive drum 1 according to the latent image.

Further, at the end of the opening 63b of the cartridge frame 63, in order to prevent the toner from leaking out from the gaps respectively generated between the cartridge frame 63 and the developing blade 16 and the developing roller 12, foaming elasticity is provided. An end seal member 32 composed of a body, felt, pile, velvet or the like is arranged, and the end seal member 32 is arranged on the back side of the developing blade and the developing roller 12 so as to cover the opening 63b. , Are pressed against the back surfaces of the developing roller 12 and the developing blade 16.

The magenta developing cartridge Dm, the cyan developing cartridge Dc, and the black developing cartridge Db are also subjected to toner development by the same mechanism as that of the yellow developing cartridge Dy. Further, the developing rollers 12 of the developing cartridges D are provided in the apparatus main body 30 when the developing cartridges D are rotationally moved to the developing position.
Is connected to a high-voltage power source for each color development (not shown) and a driving source (not shown), and a voltage is sequentially and selectively applied to each color developing cartridge D to connect the drive.

[Structure of Developing Blade] The structure of the developing blade 16 included in the developing cartridge D will be described below with reference to FIG. FIG. 4 is an exploded perspective view showing the structure of the developing blade 16 according to the first embodiment.

In FIG. 4, the developing blade 16 is a blade supporting sheet metal 1 comprising a supporting plate 101 and a pressing plate 103.
6a and an elastic blade 102 sandwiched and supported by the blade supporting sheet metal 16a. That is, the developing blade 16 has a three-layer structure, and is the support plate 101, the elastic blade 102, and the pressing plate 103 from the side closer to the developing member support frame 63A.

Positioning seat surfaces 63A1 and 63A2 for mounting the developing blade 16 are provided at both longitudinal ends of the developing member supporting frame 63A. A female screw 63A3 for fixing the developing blade 16 to the developing member supporting frame 63A is provided on the positioning seat surfaces 63A1 and 63A2.
Are provided respectively. On the seating surface 63A1 at one end in the longitudinal direction, a square dowel 63A4 having a square cross section stands upright with respect to the seating surface 63A1 outside the female screw 63A3 in the longitudinal direction.
On the seating surface 63A2 at the other end in the longitudinal direction, a round dowel 63A6 stands upright with respect to the seating surface 63A2, outside the female screw 63A3 in the longitudinal direction.

Support plate 10 which constitutes the developing blade 16
1, the elastic blade 102, one end of the pressing plate 103, so as to match the female screw 63A3 of the seat surface 63A2,
Holes for the machine screw 105 (holes into which the machine screw is loosely fitted and inserted; the same applies hereinafter) 101c, 102c, 103c are provided respectively, and at the other end, the small size is formed so as to match the female thread 63A3 of the seat surface 63A1. Holes 101d, 102 for screws 106
d and 103d are provided respectively.

The support plate 101 of the developing blade 16, the elastic blade 102, and the pressing plate 103 have holes 101c, 102c, 103c for the machine screw 105 and holes 101d, 102d, 103d for the machine screw 106 at both ends. At the same position on the outer side in the longitudinal direction, round dowels 101e and 101f are formed on the support plate 101, and round holes 102e are formed on the elastic blade 102, into which the round dowels 101e and 101f are fitted, respectively.
102f and the circular dowels 101e, 1
Round holes 103e and 103f into which 01f is fitted are provided.

Holes 101g and 103g to be fitted into the round dowels 63A6 provided on the seat surface 63A2 of the developing member supporting frame 63A are provided at one ends of the supporting plate 101 and the pressing plate 103, respectively. The hole 101g of the support plate 101 is a long hole that is long in the lateral direction that is perpendicular to the longitudinal direction.
The hole 103g is a round hole that fits exactly into the round dowel 63A6.

At the other ends of the supporting plate 101 and the pressing plate 103, the bearing surface 63A1 of the developing member supporting frame 63A is provided.
Square notch 1 that fits in the square dowel 63A4
01h and 103h are provided respectively. Support plate 101
The width of the notch 101h in the lateral direction is larger than the width of the square dowel 63A4 in the lateral direction, and
The width of 03h is a width just fitted in the square dowel 63A4.

In the above, the supporting plate 101 and the pressing plate 1
Reference numeral 03 is a metal plate having a plate thickness of about 1 to 2 mm. Since development problems occur when rust or the like occurs in these sheet metals, stainless steel is adopted or nickel or the like is plated. The elastic blade 102 is composed of a thin spring sheet metal 102a having a thickness of about 0.1 mm. The developing roller contact portion 102b on the free end side of the elastic blade 102 is
The spring force generated by the thin spring sheet metal 102a causes the developing roller 12 to abut with a certain amount of abutting force.

Details of the first embodiment will be described with reference to FIGS. 5 and 6. FIG. 5 is a front view of the developing cartridge according to the first exemplary embodiment with the developing roller removed, and FIG. 6 is a detailed front view of the developing cartridge according to the first exemplary embodiment with the developing roller removed.

As shown in FIGS. 5 and 6, in the first embodiment, both longitudinal end portions 102b1 and 102b2 of the developing roller abutting portion 102b of the elastic blade 102 with respect to the developing roller abutting portion side edge 102b3. The developing roller 12 of the elastic blade 102 is formed in an oblique shape having an inclination of about 8 °.
The side edge is retracted in the direction away from the developing roller 12.

Particularly, this slanted shape has an end seal member 32.
a, 32b, starting from the inside in the longitudinal direction towards the longitudinal end of the elastic blade 102.
02 in the width direction is shortened, and the elastic blade 102
Reduces the area of contact with the developing roller at the end in the longitudinal direction. At this time, the elastic blade 102 is
Even if 2b1 and 102b2 have an oblique shape, no gap is formed between the developing roller 12 and the developing roller 12.

According to the above construction, the elastic blade 10
The regions in which both longitudinal end portions of 2 are pressed against the developing roller 12 by the end seal members 32a and 32b are reduced, and the deviation of the contact position of the elastic blade 102 to the developing roller 12 is suppressed. It is possible to reduce the thickness of the toner coat on a part of the developing roller 12.
It is possible to prevent the toner from leaking and scattering from the ends.

(Second Embodiment) The second embodiment is characterized in that a process cartridge having a developing device according to the present invention is applied to an image forming apparatus. The process cartridge is a cartridge in which a charging unit or a cleaning unit, a developing unit, and a photosensitive drum are integrated into a cartridge,
This cartridge can be attached to and detached from the main body of the image forming apparatus.

Hereinafter, a laser beam printer as one form of the image forming apparatus according to the second embodiment will be described with reference to the sectional view of the laser beam printer having the process cartridge B shown in FIG. The members common to those in the above figures are designated by the same reference numerals, and the portions that are not particularly described have the same configuration as that of the first embodiment.

In FIG. 7, the process cartridge B
Around the photosensitive drum 1 rotating clockwise in the figure, the charging roller 2, the developing means DA, and the cleaning means 9
And each of the components are connected to the process cartridge frame 6
The cartridge 5 is integrally formed into a cartridge and is detachably mounted on the apparatus main body 30.

The laser beam L modulated by the exposure means 3 in response to the time-series electric pixel signal of the target image is output from a semiconductor laser light source (not shown) to the polygon mirror 3a, and passes through the lens 3c and the reflection mirror 3d. And the photosensitive drum 1 which has been uniformly charged by the charging means 2 in advance.
The top is exposed to form a latent image corresponding to the target image. Then, the latent image is given a toner by the developing device DA to become a toner image, and moves to a portion facing the transfer roller 6.

Next, this toner image is transferred to the paper feed cassette 5
It is transferred from a by the pickup roller 5b and transferred by the transfer roller 6 onto the recording medium P sent by the transporting means 5, fixed by the fixing means 7, and discharged to the discharging portion 8.

Here, the developing means DA has the same structure as the developing cartridge D of the first embodiment, the developing blade 16 is in pressure contact with the generatrix of the developing roller 12, and the end seal members 32a are provided at both longitudinal ends of the developing roller 12. , 32b are provided. The developing blade described in Embodiment 1 may be used as the developing blade 16.

As a result, also in the second embodiment described above, the same effect as in the first embodiment can be obtained.

[0048]

As described above, according to the present invention,
In a developing device and a process cartridge which are detachable from the main body of the electrophotographic image forming apparatus and for developing a latent image formed on an electrophotographic photosensitive member as an image carrier, a developing roller as a developer carrier, A developing blade as a developer regulating member that comes into contact with the developing roller and regulates the thickness of toner on the developing roller, and an end portion of the developing blade abutting portion side edge of the developing blade is separated from the developing roller. By retreating in the direction away from the developing roller, the area where the developing blade abuts the developing roller at the end in the longitudinal direction is reduced, so that the thickness of the toner coat at the end of the developing roller can be made thinner. It is possible to prevent leakage and scattering.

Further, in the vicinity of the end portion of the developing blade, the same effect can be obtained even if the edge of the developing blade contacting the developing roller is gradually retracted toward the end in the direction away from the developing roller. Obtainable.

As a result, a developing device capable of reducing stains in the image forming apparatus and maintaining a high quality image,
A process cartridge and an image forming apparatus can be provided.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of an electrophotographic image forming apparatus (color laser beam printer) according to a first embodiment of the present invention.

FIG. 2 is a vertical sectional view of the developing cartridge according to the first embodiment of the present invention.

FIG. 3 is a perspective view of the developing cartridge with the shutter opened according to the first embodiment of the present invention.

FIG. 4 is an exploded perspective view showing the structure of the developing blade according to the first embodiment of the invention.

FIG. 5 is a front view of the developing cartridge according to the first exemplary embodiment of the present invention with the developing roller removed.

FIG. 6 is a detailed front view of the developing cartridge according to the first exemplary embodiment of the present invention with the developing roller removed.

FIG. 7 is a vertical sectional view of an electrophotographic image forming apparatus (laser beam printer) equipped with a process cartridge according to a second embodiment of the present invention.

[Explanation of symbols]

B ... Process cartridges D, Dy, Dm, Dc, Db ... Developing cartridge (developing device) DA ... Developing means P ... Recording medium L ... Laser beam 1 ... Photosensitive drum 2 ... Charging roller 3 ... Scanner section 3a ... Polygon mirror 3c ... Lens 3d ... Reflection mirror 4 ... Intermediate transfer body 5 ... Conveying means 5a ... Paper feeding cassette 5b ... Pickup roller 6 ... Transfer roller 7 ... Fixing means 8 ... Ejection section 9 ... Cleaning means 10 ... Rotary shaft 11 ... Rotary unit 12 ... Developing roller 12a ... Metal shaft 12b ... Rubber layer 15 ... Toner feeding member 16 ... Developing blade 16a ... Blade supporting sheet metal 19 ... Coating roller 30 ... Device main body 32a, 32b ... End seal member 63 ... Cartridge frame 63a ... Toner storage portion 63b ... Aperture 63A ... Developing member support frames 63A1, 63A2 ... Positioning seat surface 63A3 ... Female thread 63A4 ... Square dowel 63A6 ... Round dowel 63B ... Toner frame 63C ... Cover frame 63D, 63E ... Side cover 63F ... Coupling frame 64 ... Shutter 65 ... Process cartridge frame 101 ... Support plate 101c, 101
d ... Holes 101e and 101f for small screws ... Round dowels 101g ... Holes 101h ... Notches 102 ... Elastic blades 102a ... Thin sheet metal springs 102b ... Developing roller abutting portions 102b1, 102b2 ... Developing roller abutting portion ends 102b3 ... Developing Roller contact edge 102c, 102d ... Small screw hole 102e, 102f ... Round hole 103 ... Pressing plate 103c, 103d ... Small screw hole 103e, 103
f ... Round hole 103g ... Hole 103h ... Notch 105 ... Machine screw 106 ... Machine screw

Claims (5)

[Claims] 1. A developing container having an opening facing the image carrier and containing a developer, and an electrostatic latent image on the image carrier rotatably supported by the opening of the developing container. A developer carrying member carrying and carrying a developer for developing; and a developer regulating member for contacting a peripheral surface of the developer carrying member to regulate the layer thickness of the developer on the developer carrying body. A rear surface of the developer carrying member and the developer regulating member, the rear surface of the developer carrying member and the developer regulating member being arranged at the end of the developing container so as to cover the opening. Is pressed against
An end seal member for preventing the developer from leaking through the gaps respectively formed between the developer container, the developer carrying member, and the developer regulating member, and the developer of the developer regulating member. A developing device characterized in that, in the vicinity of a longitudinal end portion on the side of contact with a carrier, the edge of the developer regulating member on the side of the developer carrier is retracted in a direction away from the developer carrier. 2. The developer carrying member edge of the developer restricting member is gradually moved toward the end in the vicinity of the end of the developer restricting member on the side of contact with the developer carrying member. The developing device according to claim 1, wherein the developing device is retracted in a direction away from the developing device. 3. The developing device according to claim 1, an image bearing member developed by the developing device, a cleaning unit for cleaning the image bearing member, and a charging unit for charging the image bearing member. A process cartridge comprising: 4. An image forming apparatus comprising the developing device according to claim 1. 5. An image forming apparatus comprising the process cartridge according to claim 3.