JP4310091B2 - Developing cartridge and process cartridge - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a developing unit provided in an image forming apparatus, a process cartridge detachably attached to the image forming apparatus, and a protection member thereof.
[0002]
Here, the image forming apparatus forms an image on a recording medium using an electrophotographic image forming system. Examples of the electrophotographic image forming apparatus include an electrophotographic copying machine, an electrophotographic printer (laser beam printer, LED printer, etc.), a facsimile machine, a word processor, and the like.
[0003]
The process cartridge refers to a unit having at least developing means that can be attached to and detached from the image forming apparatus main body, or a unit having a photosensitive drum and developing means.
[0004]
The developing unit means a developing unit for developing a latent image formed on the electrophotographic photosensitive drum and a member associated therewith.
[0005]
[Prior art]
Conventionally, the following configuration is known as an image forming apparatus that forms an image on a recording medium by an electrophotographic method. That is, a latent image formed on the electrophotographic photosensitive drum is made to face a developing unit containing a developer so that the latent image is visualized and transferred to a recording medium. In the multicolor image forming apparatus, these development and transfer operations are performed for each color to obtain a multicolor image on a recording medium.
[0006]
Further, as the developing method, a contact developing method in which a developing roller is brought into contact with a photosensitive drum, a jumping developing method in which a constant interval is provided between the developing roller and the photosensitive drum, and the like are known. There is also known a process cartridge configuration in which the developing unit can be attached to and detached from the image forming apparatus main body so as to reduce the maintenance work of the user.
[0007]
Further, in the developing unit or the process cartridge, various auxiliary members have been proposed as means for maintaining quality from manufacture and shipment until the user starts use. For example, Patent Documents 1 to 4 disclose a configuration in which a sheet member is sandwiched between a developing blade and a D roller.
[0008]
[Patent Document 1]
JP-A-7-311536 [Patent Document 2]
JP 2001-290370 A [Patent Document 3]
USP-5749026 specification [Patent Document 4]
USP-6009287 specification.
[0009]
[Problems to be solved by the invention]
Conventionally, in the case of a contact development method in which a non-magnetic toner and an elastic developing roller are brought into contact with a photosensitive drum to form a toner image, the developing roller is made of an elastic body in order to avoid scratches or wear due to rubbing against the photosensitive drum. It is preferable to use a roller having the same. As the elastic body, a solid rubber single layer or a solid rubber layer coated with a resin coating in consideration of charge imparting property to the toner is used.
[0010]
Further, a configuration is known in which a toner supply roller such as a sponge roller and a developing blade that regulates a toner layer on the developing roller are pressed against the developing roller.
[0011]
The developing blade presses the developing roller to form a thin layer of toner on the outer periphery of the developing roller, and applies charge (friction charging) to the toner. In particular, a metal plate such as phosphor bronze, stainless steel or carbon steel provided with a pressure contact means, a metal thin plate having spring properties such as phosphor bronze, stainless steel or carbon steel, or a material coated with a resin on the surface of the metal thin plate. Preferably, both have a configuration in which a predetermined contact pressure is secured to the developing roller and is always in contact during use.
[0012]
As described above, in the case where the developing blade is pressed against the developing roller having an elastic body, the developing blade is always in contact with the developing roller at the time of use. A state where the roller is deformed is maintained.
[0013]
Therefore, approximately 1 mm formed at the contact portion between the developing blade and the developing roller due to the influence of various conditions such as the standing time from the time of manufacture to the start of use by the user, vibration, impact, temperature and humidity environment, etc. The width deformation may be difficult to recover.
[0014]
In this case, when the user starts use without the deformation being sufficiently recovered, the developing roller rotates when the deformed portion passes through the developing blade contact portion, so that the contact pressure by the developing blade is increased. Minor fluctuations occur. As a result, the toner coat thickness, toner charging characteristics, and the like of the deformed portion change, and a horizontal streak corresponding to the rotation cycle of the developing roller may appear in the image.
[0015]
The present invention has been made to solve the above problems of the prior art, it is an object of the developing cartridge which can obtain a good image from the start of use, and, to provide a process cartridge It is in.
[0016]
In order to achieve the above object, in the developing cartridge according to the present invention,
In the developing cartridge detachable from the electrophotographic image forming apparatus main body,
A developing roller for developing the electrostatic latent image formed on the electrophotographic photosensitive member, the developing roller having a roller portion made of an elastic body and a shaft portion supporting the roller portion;
A developer regulating member that contacts the roller unit and regulates the amount of developer on the roller unit;
A protective member that is detachably sandwiched between the developing roller and the developer regulating member, and is formed of urethane foam that is compressed and deformed by being sandwiched between the developing roller and the developer regulating member. And an auxiliary member made of a polyethylene terephthalate sheet that supports the pressure dispersion material, and the auxiliary member is disposed between the roller portion and the developer regulating member together with the pressure dispersion material. A protective member in contact with the auxiliary member, the developer regulating member in contact with the pressure dispersion material, and a roller member in contact with the pressure dispersion material;
It is characterized by having.
[0017]
In the process cartridge that can be attached to and detached from the electrophotographic image forming apparatus main body,
An electrophotographic photoreceptor;
A developing roller for developing an electrostatic latent image formed on the electrophotographic photosensitive member, the developing roller having a roller portion made of an elastic body, and a shaft portion supporting the roller portion;
A developer regulating member that contacts the roller unit and regulates the amount of developer on the roller unit;
A protective member that is detachably sandwiched between the developing roller and the developer regulating member, and is formed of urethane foam that is compressed and deformed by being sandwiched between the developing roller and the developer regulating member. And an auxiliary member made of a polyethylene terephthalate sheet that supports the pressure dispersion material, and the auxiliary member is disposed between the roller portion and the developer regulating member together with the pressure dispersion material. A protective member in contact with the auxiliary member, the developer regulating member in contact with the pressure dispersion material, and a roller member in contact with the pressure dispersion material;
It is characterized by having.
[0019]
According to the above arrangement, the protective member between the developer regulating member and the developing roller by clamping, to suppress the deformation of the developing roller by enlarging the contact nip reduces the contact pressure, developing A good image can be provided from the start of use of the cartridge or the process cartridge.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
Exemplary embodiments of the present invention will be described in detail below with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention only to those unless otherwise specified. Absent. Further, the materials, shapes, etc. of the members once described in the following description are the same as those in the first description unless otherwise described.
[0024]
In the following description, “device front” refers to the upstream surface of the recording medium transported from the transfer process to the fixing process (right side in FIG. 1), and “left and right with respect to the device main body and process cartridge” Left or right when viewed from the front of the device. The “longitudinal direction” is a direction parallel to the surface of the recording medium and intersecting (substantially orthogonal) with the conveyance direction of the recording medium.
[0025]
(Overall configuration of color image forming apparatus and image forming process)
First, the overall configuration of the color image forming apparatus will be schematically described with reference to FIG. FIG. 1 is a longitudinal sectional view showing a schematic configuration of a color laser beam printer in which a developing cartridge, a drum cartridge, and an intermediate transfer body unit are loaded in an image forming apparatus main body, which is an embodiment of a color electrophotographic image forming apparatus according to the present embodiment. It is.
[0026]
As shown in FIG. 1, the main body of the color image forming apparatus irradiates an image carrier (hereinafter referred to as “photosensitive drum”) 1 that rotates counterclockwise by irradiating a light image based on image information from exposure means 3. An electrostatic latent image is formed, and a developer image (hereinafter referred to as “toner image”) is formed at the development position of the developer cartridge. In synchronism with the formation of the toner image, the recording medium is conveyed by a conveying means including a pickup roller 18, a conveying roller pair 19, a registration roller pair 7, and the like, and the toner image formed on the photosensitive drum 1 is transferred to the intermediate transfer member 5a. Transcribed.
[0027]
In the case of multicolor development, the four color toner images are superimposed on the intermediate transfer member 5a by being repeated four times with yellow, magenta, cyan, and black.
[0028]
Next, the toner image on the intermediate transfer member 5a is transferred to a recording medium by the secondary transfer roller 11, and the recording medium is conveyed to a fixing device 8 having a pressure roller and a heating roller to fix the transferred toner image. It is configured to discharge to the discharge unit 10.
[0029]
The image forming process will be described in more detail.
[0030]
The photosensitive drum 1 rotates in the arrow direction (counterclockwise) in FIG. 1 in synchronization with the rotation of the intermediate transfer belt 5a. The charging device 2 uniformly charges the surface of the photosensitive drum 1. The exposure means 3 irradiates the charged photosensitive drum 1 surface with image light based on each color image information, for example, image light based on yellow image information, and the electrostatic latent image corresponding to the yellow image on the photosensitive drum 1. Form.
[0031]
The exposure means is performed through the following steps. The exposure means 3 irradiates the photosensitive drum 1 with light based on image information read from an external device or the like, and is roughly composed of a laser diode, a polygon mirror, a scanner motor, an imaging lens, and a reflection mirror.
[0032]
When an image signal is given from an external device or the like, the laser diode emits light according to the image signal and irradiates the polygon mirror as the image light. The polygon mirror is rotated at a high speed by a scanner motor, and image light reflected by the polygon mirror selectively exposes the surface of the photosensitive drum 1 through an imaging lens and a reflecting mirror, and as a result, electrostatically is applied to the photosensitive drum. A latent image is formed.
[0033]
In synchronism with the formation of the electrostatic latent image, the yellow developing cartridge (developing unit) 4Y is rotated to the developing position, and a predetermined bias voltage is applied to cause yellow toner to adhere to the electrostatic latent image for development. Thereafter, a yellow toner image on the photosensitive drum 1 is primarily transferred onto the intermediate transfer belt 5a by applying a bias voltage having a polarity opposite to that of the toner to the pressing roller (primary transfer roller) 5j of the intermediate transfer belt 5a. The
[0034]
When the primary transfer of the yellow toner image is completed as described above, the next developing cartridge (4M) of the developing device 4 rotates and is positioned at a position facing the photosensitive drum 1. By repeating the steps of forming the electrostatic latent image, developing, and primary transfer as described above for each color of magenta (M), cyan (C), and black (Bk) in sequence, the process is performed on the intermediate transfer belt 5a. Four color toner images are superimposed on each other.
[0035]
Meanwhile, the secondary transfer roller 11 is in a non-contact state with the intermediate transfer belt 5a, and the cleaning charging roller 5f as a cleaning unit is also in a non-contact state with the intermediate transfer belt 5a.
[0036]
As shown in FIG. 1, the secondary transfer roller 11 is pressed against the intermediate transfer belt 5a after four color toner images are formed on the intermediate transfer belt 5a. Further, in synchronization with the rotation of the intermediate transfer belt 5a, the recording medium waiting at a predetermined position in the vicinity of the registration roller pair 7 as the feeding means is sent to the nip portion between the intermediate transfer belt 5a and the secondary transfer roller 11. It is.
[0037]
Here, immediately before the registration roller pair 7, a pre-registration sensor 14 is provided that detects the leading edge of the recording medium, interrupts the rotational driving force of the registration roller pair 7, and waits the recording medium at a predetermined position. .
[0038]
A bias voltage having a polarity opposite to that of the toner is applied to the secondary transfer roller 11, and the toner image on the intermediate transfer belt 5 a is secondarily transferred collectively onto the surface of the conveyed recording medium.
[0039]
The recording medium onto which the toner image has been secondarily transferred in this manner is conveyed to the fixing device 8 via the conveying belt unit 12, where a plurality of color toner images are fixed.
[0040]
The recording medium on which the toner image is fixed is conveyed along the paper discharge guide 15 by the discharge roller pair 13 and is discharged by the discharge roller pair 9 to the discharge unit 10 above the color image forming apparatus A, thereby completing the image formation.
[0041]
On the other hand, the cleaning charging roller 5f is brought into pressure contact with the intermediate transfer belt 5a after the completion of the secondary transfer, and the residual toner remaining on the intermediate transfer belt 5a is applied with a predetermined bias voltage to remove the residual charge.
[0042]
The discharged residual toner is electrostatically retransferred from the intermediate transfer belt 5a to the photosensitive drum 1 through the primary transfer nip portion, and the surface of the intermediate transfer belt 5a is cleaned.
[0043]
The residual toner remaining after the secondary transfer that has been retransferred to the photosensitive drum 1 is removed by the cleaning blade 6 for the photosensitive drum 1 and collected in the cleaning container 20.
[0044]
The collected residual toner follows a conveyance path (not shown) for conveying it as waste toner, and is collected and accumulated in the waste toner box 16.
[0045]
(Developer cartridge configuration)
Next, the schematic configuration of the developing cartridge will be described with reference to FIGS. FIG. 2 is a schematic longitudinal sectional view of the developing cartridge 4Y (4M, 4C, 4Bk has the same schematic configuration and description thereof is omitted), and FIG. 3 is a perspective view thereof.
[0046]
The developing device 4 is for visualizing the electrostatic latent image on the photosensitive drum 1, and in this embodiment, four developments that enable development of each color of yellow, magenta, cyan, and black are possible. It is composed of cartridges 4Y, 4M, 4C, 4Bk.
[0047]
In this embodiment, the developing cartridge, which is a cartridge-type developing unit that is detachable from the image forming apparatus, will be described in detail. Of course, the developing cartridge is not limited to this configuration, but a fixed developing unit fixed to the image forming apparatus. Also, the present invention can be preferably applied.
[0048]
As shown in FIGS. 2 and 3, the developing cartridge 4Y has a protective cover 360 that is detachably attached to the developing cartridge 4Y for the purpose of protecting the developing roller when not inserted into the main body of the image forming apparatus.
[0049]
As shown in FIG. 1, the developing cartridges 4Y, 4M, 4C, and 4Bk are detachably held by mounting means formed on a rotary unit 301 that rotates about an axis, and each developing cartridge is used for image formation. While being held by the rotary unit 301, it rotates around the shaft, the predetermined developing cartridge stops at a position facing the photosensitive drum 1, and a developing roller 305 described later is positioned so as to contact the photosensitive drum 1. Thereafter, a visible image is formed corresponding to the electrostatic latent image on the photosensitive drum 1.
[0050]
At the time of color image formation, the rotary unit 301 rotates every rotation of the intermediate transfer belt 5a, and the developing process is performed in the order of the yellow developing cartridge 4Y, the magenta developing cartridge 4M, the cyan developing cartridge 4C, and then the black developing cartridge 4Bk.
[0051]
As shown in FIG. 2, the developing cartridge 4Y feeds the toner in the developing container 302 constituting the developing frame to the toner supply roller 304 by the toner agitating member 303, and rotates the toner supply roller 304 that rotates in the clockwise direction in the drawing. A thin layer of toner is applied to the outer periphery of the developing roller 305 that rotates in the clockwise direction in the figure by a developing blade 332 that is pressed against the outer periphery of the roller 305, and an electric charge is applied to the toner (friction charging).
[0052]
Then, by applying a developing bias to the developing roller 305 facing the photosensitive drum 1 on which the latent image is formed, toner development is performed on the photosensitive drum 1 in accordance with the latent image. For the magenta developing cartridge 4M, the cyan developing cartridge 4C, and the black developing cartridge 4Bk, toner development is performed by the same mechanism as described above.
[0053]
Further, each developing roller 305 of each developing cartridge is connected to a high-voltage power source and a drive (not shown) for each color development provided in the printer body when each developing cartridge is rotated to the developing position. A voltage is selectively applied sequentially to the driving device.
[0054]
Here, the developing cartridge according to the present embodiment is a contact developing method in which the photosensitive drum 1 and the developing roller 305 are in contact with each other for development. The photosensitive drum 1 has a photosensitive layer provided on a metal cylinder such as stainless steel, copper or aluminum alloy, and the developing roller 305 in contact with the photosensitive drum 1 has an elastic roller formed on a shaft of a metal rod or the like.
[0055]
As this elastic body, a solid rubber single layer or a solid rubber layer coated with a resin coating in consideration of charge imparting property to toner is used. Further, the developing blade 332 that forms a thin layer of toner on the outer periphery of the developing roller 305 by being brought into pressure contact with the developing roller 305 and applies charge (friction charging) to the toner has a spring property such as phosphor bronze or stainless steel. A thin metal plate or a metal surface coated with resin, and abuts against the developing roller 305 while maintaining a predetermined pressure.
[0056]
【Example】
An embodiment of the present invention will be schematically described with reference to FIGS. 4 and 5 are cross-sectional views of the developing cartridge in a state in which the protective member of this embodiment is inserted, and FIG. 6 is a cross-sectional view of the developing cartridge in a state in which the protective member is not inserted.
[0057]
As shown in FIG. 4, the protective member 333 is in contact with a pressure dispersion member 333 a having an action of dispersing the contact pressure of the developing blade 332 against the developing roller 305. One end of the auxiliary member 333b joined integrally with the pressure dispersion material 333a is in contact with the developing blade 332, and is sandwiched between the developing roller 305 and the development blade 332 together with the pressure dispersion material 333a. The other end of the auxiliary member 333b is bonded to the protective cover 360 with a double-sided tape or the like in the region of the bonding layer 333c.
[0058]
Therefore, the contact pressure of the developing blade 332 to the developing roller 305 can be dispersed from the time when the developing cartridge is manufactured until the user starts using it, and deformation of the developing roller 305 can be suppressed. Further, by removing the protective cover 360 at the time of initial use of the process cartridge, the protective member 333 is also extracted together, and it is possible to prevent forgetting to remove the protective member 333 when using the process cartridge.
[0059]
Next, details of specific embodiments of the present invention will be described.
[0060]
(Mechanism of pressure dispersion)
First, the mechanism of pressure dispersion will be described. As shown in FIG. 7, when the developing blade 332 is brought into contact with the developing roller 305 at, for example, a linear pressure of about 1.96 N / m (20 gf / cm), the contact width between the developing roller 305 and the developing blade is experimentally determined. As a result, the surface pressure received by the developing roller 305 is about 19.6 × 10 ³ N / m ² ( ² gf / mm ² ).
[0061]
Therefore, as shown in FIG. 8, the pressure dispersion material 333a is compressed and deformed by interposing the pressure dispersion material 333a between the developing roller 305 and the development blade 332, and the contact width is experimentally expanded to about 3 to 5 mm. Since the surface pressure of the developing blade 332 to the developing roller 305 is substantially reduced, deformation of the developing roller 305 can be suppressed.
[0062]
(Pressure dispersion material)
Next, details of the pressure dispersion material 333a that can be suitably used in the present embodiment will be described. The pressure dispersion member 333a sandwiched between the development roller 305 and the development blade 332 preferably has the following functions in addition to the pressure dispersion action.
[0063]
(1) Do not chemically attack other components during storage over time.
[0064]
(2) There shall be no generation of burns due to vibration during transportation.
[0065]
(3) Excellent operability.
[0066]
It has been found experimentally that the following two types of configurations are preferably employed.
[0067]
First, as shown in FIG. 5, it was found that a urethane foam having a thickness of about 0.5 mm to 2 mm can obtain desirable characteristics in terms of not only pressure dispersibility but also chemical attack with time, generation of fluff, operability, and the like.
[0068]
Even with the same urethane foam, when the thickness is 2 mm or more, the insertion / removability is significantly deteriorated. Conversely, when the thickness is 0.5 mm or less, the insertion / removability is improved experimentally, but the pressure dispersion effect cannot be sufficiently obtained. It was. Further, although fiber members such as cotton piles having a bristle of about 1.2 mm can experimentally ensure pressure dispersibility, they have not solved the problem of fluff.
[0069]
Moreover, as a thing which was not experimentally effective, neither paper nor a polyethylene terephthalate sheet | seat etc. have what has substantially no pressure dispersion effect | action. Therefore, a urethane foam having a thickness of 0.5 to 2 mm as the pressure dispersion material 333a having the above-mentioned pressure dispersibility and not causing chemical attack on other components during storage over time, no generation of injuries, and excellent operability. Is desirable.
[0070]
Moreover, as a structure which has a pressure dispersion means equivalent to the said urethane foam, as shown in FIG. 6, the pressure dispersion material 333a was made into the integrally molded article by resin, such as polyethylene and a polypropylene, for example.
[0071]
In this case, the radius of curvature R2 of the cross-sectional shape of the pressure dispersion member 333a on the developing roller side is experimentally shown in FIG. 6 where the radius of curvature R2 is slightly R2> R1, as shown in FIG. It was confirmed to have an effect.
[0072]
This is because the urethane foam is compressed and deformed by the contact of the developing blade 332 to follow the outer diameter shape of the developing roller 305 and obtain a pressure dispersion effect. By using a resin such as polyethylene or polypropylene, the same pressure dispersion effect is obtained.
[0073]
(Auxiliary member)
The pressure dispersion material 333a using a foaming agent such as urethane foam in the sandwiching operation at the time of actual assembly and the user's extraction operation has a large frictional resistance with the developing roller 305 or the developing blade 332 and sufficient strength. Not done. For this reason, the pressure dispersion member 333a alone is extremely inferior in actual workability such as being difficult to insert and pulling out.
[0074]
In the case of a molded resin, there is a risk of touching the developing roller 305 when the pressure dispersion member 333a is inserted or withdrawn, or forgetting to remove it.
[0075]
Therefore, as shown in FIGS. 4 and 5, the auxiliary member 333b is integrally formed. The auxiliary member 333b is preferably a polyethylene terephthalate sheet having a thickness of about 150 μm experimentally when the developing blade 332 is a thin metal plate having a spring property such as phosphor bronze or stainless steel and the surface is not coated with a resin.
[0076]
Further, when the surface of the developing blade 332 is coated with resin, it has been experimentally found that the auxiliary member 333b may damage the surface of the developing blade 332 when the protective member 333 is inserted or removed. In that case, the contact surface of the auxiliary member 333b with the developing blade 332 should be provided with a lubricating action such as Teflon (registered trademark) or silicon coating, and it was experimentally found that release paper is preferable.
[0077]
In any case, it has been experimentally found that the auxiliary member 333b is set to be closer to the developing blade 332 than the developing roller 305 in terms of insertion / removal.
[0078]
(Integrated with protective cover)
Next, for the purpose of ensuring usability when the user pulls out the protective member 333, the other end of the protective member 333 opposite to the sandwiched portion between the developing blade 332 and the developing roller 305 is integrated with the protective cover 360. Thus, the protective member 333 can be reliably removed without requiring special consciousness for the user.
[0079]
(Configuration of protective member (joining of each member))
As described above, the protective member 333 is basically composed of the pressure dispersion material 333a and the auxiliary member 333b, the pressure dispersion material 333a is inserted into the developing roller 305, the auxiliary member 333b is inserted in the direction in contact with the developing blade 332, and the other end is a protective cover. 360 is integrated.
[0080]
In this embodiment, the pressure dispersion material 333a and the auxiliary member 333b, and the auxiliary member 333b and the protective cover 360 are joined by using a double-sided tape as the joining means of the joining layer 333c. However, there is no problem as long as the material does not chemically attack components such as the developing roller and the photosensitive drum over time and can obtain a sufficient bonding strength. Moreover, about a joining area | region, it is not specifically limited on the conditions that it does not peel.
[0081]
As described above, the specific embodiments of the present invention have been described. However, the present invention is not limited to the above-described color image forming apparatus and the above-described embodiments, and at least the distribution of the contact pressure of the developing blade 332 to the developing roller 305 is distributed. It goes without saying that the protective member 333 having an action can be applied to a configuration in which the protective member 333 is sandwiched between the developing blade 332 and the developing roller 305. Obviously, it does not have a function as a sealing material.
[0082]
【The invention's effect】
As described above, according to the present invention, the deformation of the developing roller caused by the developer regulating member coming into contact with the developing roller from the time of manufacture of the process cartridge or the developing cartridge to the initial use by the user It can be suppressed by the dispersing material, and a good image can be obtained. Further , by setting the auxiliary member that supports the pressure dispersion material on the side in contact with the developer regulating member, it is possible to satisfactorily insert and remove the protective member between the developing roller and the developer regulating member.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of an image forming apparatus according to an embodiment.
FIG. 2 is a schematic longitudinal sectional view of a developing cartridge according to the present embodiment.
FIG. 3 is an overall perspective view of the developing cartridge according to the exemplary embodiment.
FIG. 4 is a cross-sectional view of the developing cartridge in a state where a protective member is inserted according to the present embodiment.
FIG. 5 is a detailed sectional view of a protective member (pressure dispersion material: urethane foam) according to the present embodiment.
FIG. 6 is a detailed cross-sectional view of a protective member (pressure dispersion material: soft resin) of this example.
FIG. 7 is a detailed cross-sectional view showing a blade contact state when there is no protective member.
FIG. 8 is a detailed cross-sectional view showing a blade contact state when there is a protective member.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Photosensitive drum 2 Charging apparatus 3 Exposure means 4 Developing apparatus 4Y, 4M, 4C, 4Bk Developing cartridge (developing unit)
5f Cleaning charging roller 5a Intermediate transfer belt (intermediate transfer member)
6 Cleaning blade 7 Registration roller pair 8 Fixing device 9 Discharge roller pair 10 Discharge unit 11 Secondary transfer roller 12 Conveying belt unit 13 Discharge roller pair 14 Pre-registration sensor 15 Discharge guide 16 Waste toner box 18 Pickup roller 19 Conveying roller pair 20 Cleaning container 301 Rotary unit 302 Developing container 303 Toner stirring member 304 Toner supply roller 305 Developing roller 332 Developing blade 333 Protection member 333a Pressure dispersion material 333b Auxiliary member 333c Bonding layer 360 Protective cover A Color image forming apparatus

Claims (2)

In the developing cartridge detachable from the electrophotographic image forming apparatus main body,
A developing roller for developing the electrostatic latent image formed on the electrophotographic photosensitive member, the developing roller having a roller portion made of an elastic body and a shaft portion supporting the roller portion;
A developer regulating member that contacts the roller unit and regulates the amount of developer on the roller unit;
A protective member that is detachably sandwiched between the developing roller and the developer regulating member, and is formed of urethane foam that is compressed and deformed by being sandwiched between the developing roller and the developer regulating member. And an auxiliary member made of a polyethylene terephthalate sheet that supports the pressure dispersion material, and the auxiliary member is disposed between the roller portion and the developer regulating member together with the pressure dispersion material. A protective member in contact with the auxiliary member, the developer regulating member in contact with the pressure dispersion material, and a roller member in contact with the pressure dispersion material;
A developing cartridge. In a process cartridge that can be attached to and detached from the electrophotographic image forming apparatus main body,
An electrophotographic photoreceptor;
A developing roller for developing an electrostatic latent image formed on the electrophotographic photosensitive member, the developing roller having a roller portion made of an elastic body, and a shaft portion supporting the roller portion;
A developer regulating member that contacts the roller unit and regulates the amount of developer on the roller unit;
A protective member that is detachably sandwiched between the developing roller and the developer regulating member, and is formed of urethane foam that is compressed and deformed by being sandwiched between the developing roller and the developer regulating member. And an auxiliary member made of a polyethylene terephthalate sheet that supports the pressure dispersion material, and the auxiliary member is disposed between the roller portion and the developer regulating member together with the pressure dispersion material. A protective member in contact with the auxiliary member, the developer regulating member in contact with the pressure dispersion material, and a roller member in contact with the pressure dispersion material;
A process cartridge.

Images