JP2004125924A - Protecting member, development unit and process cartridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a developing unit, a process cartridge and its protecting member in which a good image can be obtained from the start of use. <P>SOLUTION: A protecting member 33 is crimped to be able to be extracted between a developing roller 305 carrying the toner and a developing blade 332 which is brought into a pressurized contact with a developing roller 305 and restricting a toner layer carried on the developing roller 305. A pressure dispersing material 333a to distribute the pressurizing force of the developing blade 332 against the developing roller 305 is provided. Thus, deformation of the developing roller at the use starting time of the developing unit can be prevented and the good image can be obtained. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a developing unit provided in an image forming apparatus, a process cartridge detachable from the image forming apparatus, and a protection member therefor.
[0002]
Here, the image forming apparatus forms an image on a recording medium using an electrophotographic image forming method. Examples of the electrophotographic image forming apparatus include, for example, an electrophotographic copying machine, an electrophotographic printer (such as a laser beam printer and an LED printer), a facsimile machine, and a word processor.
[0003]
The process cartridge refers to a unit having at least a developing unit detachable from the image forming apparatus main body, or a unit having a photosensitive drum and a developing unit.
[0004]
The developing unit is a unit composed of a developing unit for developing a latent image formed on an electrophotographic photosensitive drum and members attached thereto.
[0005]
[Prior art]
2. Description of the Related 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 selectively formed on an electrophotographic photosensitive drum is made to face a developing unit containing a developer to visualize the latent image and transfer the latent image to a recording medium. In the multicolor image forming apparatus, these development and transfer operations are further 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 certain interval is provided between the developing roller and the photosensitive drum, and the like are known. There is also known an image forming apparatus in which the developing unit is detachably mountable to a main assembly of the image forming apparatus so as to reduce maintenance work for a user.
[0007]
Further, in the developing unit or the process cartridge, various auxiliary members have been proposed as means for maintaining the quality from the time of production and shipment until the user starts using the same. 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]
Japanese Patent Application Laid-Open No. 7-31536 [Patent Document 2]
JP 2001-290370 A [Patent Document 3]
USP-5749026 [Patent Document 4]
USP-600287.
[0009]
[Problems to be solved by the invention]
Conventionally, in the case of a contact developing 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 and abrasion caused by rubbing with the photosensitive drum. It is preferable to use a roller having As the elastic body, a solid rubber single layer or a solid rubber layer coated with a resin in consideration of the charging 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 for regulating a toner layer on the developing roller are brought into pressure contact with the developing roller.
[0011]
The developing blade presses against the developing roller to form a thin layer of toner on the outer periphery of the developing roller and imparts electric charge (frictional charging) to the toner. In particular, those provided with a press-contact means to a metal such as phosphor bronze or stainless steel or carbon steel, a thin metal plate having a spring property such as phosphor bronze or stainless steel or carbon steel, or a metal thin plate surface coated with resin. Preferably, each of them has a configuration in which a predetermined contact pressure is secured to the developing roller and the developing roller is always in contact when used.
[0012]
As described above, in the case of the configuration in which the developing blade is pressed against the developing roller having an elastic body, the developing blade is always in contact with the developing roller, so that the developing roller has a width of about 1 mm at the contact portion between the developing roller and the developing blade due to the contact pressure. The deformed state of the roller is maintained.
[0013]
Therefore, due to the effects of various conditions such as a standing time from the time of manufacture and shipment to the start of use by the user, vibration, shock, temperature and humidity environment, etc., about 1 mm formed at the contact portion between the developing blade and the developing roller. The deformation of the width may not be easily restored.
[0014]
In this case, when the user starts use in a state where the deformation is not sufficiently recovered, the developing roller is rotating when the deformed portion passes through the developing blade abutting portion. , Etc., occur. As a result, the toner coat thickness and toner charging characteristics of the deformed portion may change, and horizontal streaks corresponding to the rotation cycle of the developing roller may appear on the image.
[0015]
SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the related art, and an object of the present invention is to provide a developing unit, a process cartridge, and a protective member thereof capable of obtaining a good image from the start of use. It is in.
[0016]
[Means for Solving the Problems]
In order to achieve the above object, in the protective member according to the present invention,
A protection member detachably sandwiched between a developing roller that carries toner and a developing blade that presses against the developing roller and regulates a toner layer carried on the developing roller,
A pressure dispersing material for dispersing the pressing force of the developing blade on the developing roller is provided.
[0017]
In the developing unit according to the present invention,
A developing unit attached to the image forming apparatus,
A developing roller for carrying toner,
A developing blade that presses against the developing roller and regulates a toner layer carried on the developing roller;
A protective member that is detachably sandwiched between the developing roller and the developing blade when the developing unit is not used,
Having a toner supply opening and containing a toner,
The protection member includes a pressure dispersing material for dispersing a pressing force of the developing blade against the developing roller.
[0018]
In the process cartridge according to the present invention,
A process cartridge detachable from the image forming apparatus,
A developing roller for carrying toner,
A developing blade that presses against the developing roller and regulates a toner layer carried on the developing roller;
When the process cartridge is not used, a protective member that is detachably sandwiched between the developing roller and the developing blade,
Having a toner supply opening and containing a toner,
The protection member includes a pressure dispersing material for dispersing a pressing force of the developing blade against the developing roller.
[0019]
According to the above-described configuration, the pressure dispersing material provided on the protective member is sandwiched between the developing blade and the developing roller, so that the contact nip is enlarged and the contact pressure is reduced, thereby reducing the deformation of the developing roller. Thus, good images can be provided from the start of use of the developing unit and the process cartridge.
[0020]
The pressure dispersing material is preferably a foam.
[0021]
It is preferable that a portion of the pressure dispersing material that comes into contact with the developing roller has a shape substantially equal to an outer diameter of the developing roller.
[0022]
It is preferable that a protective cover for protecting the surface of the developing roller exposed to the outside is provided at one end of the auxiliary member provided with the pressure dispersing material.
[0023]
BEST MODE FOR CARRYING OUT THE INVENTION
Preferred embodiments of the present invention will be illustratively 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 thereto unless otherwise specified. Absent. The materials, shapes, and the like of the members once described in the following description are the same as those in the first description unless otherwise specified.
[0024]
In the following description, the “front side of the apparatus” refers to the upstream side of the conveyance of the recording medium from the transfer process to the fixing process (right side in FIG. 1), and “the left and right sides of the apparatus body and the process cartridge” means Left or right when viewed from the front of the device. The “longitudinal direction” is a direction that is parallel to the surface of the recording medium and intersects (substantially orthogonal) to the transport 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 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 a light image based on image information from an exposure unit 3 and statically rotates an image carrier (hereinafter, referred to as a “photosensitive drum”) 1 that rotates counterclockwise. An electrostatic latent image is formed, and a developer image (hereinafter, referred to as “toner image”) is formed at a developing position of the developing cartridge. Then, the recording medium is conveyed by conveyance means including a pickup roller 18, a conveyance roller pair 19, a registration roller pair 7 and the like in synchronization with the formation of the toner image, 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, yellow, magenta, cyan, and black are repeated four times to form the toner images of the four colors on the intermediate transfer member 5a in a superimposed state.
[0028]
Next, the toner image on the intermediate transfer member 5a is transferred onto 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, where the transferred toner image is fixed. 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 direction of the arrow in FIG. 1 (counterclockwise) 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 unit 3 irradiates the charged photosensitive drum 1 surface with image light based on image information of each color, for example, image light based on yellow image information, and forms an electrostatic latent image corresponding to a yellow image on the photosensitive drum 1. To form
[0031]
Exposure 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 generally constituted by a laser diode, a polygon mirror, a scanner motor, an imaging lens, and a reflection mirror.
[0032]
Then, when an image signal is given from an external device or the like, the laser diode emits light in accordance with the image signal and irradiates the polygon mirror with the image light. The polygon mirror is rotated at a high speed by a scanner motor, and the image light reflected by the polygon mirror selectively exposes the surface of the photosensitive drum 1 via an imaging lens and a reflection mirror. Form a latent image.
[0033]
In synchronization with the formation of the electrostatic latent image, the yellow developing cartridge (developing unit) 4Y is rotated to the developing position, a predetermined bias voltage is applied, and yellow toner is adhered to the electrostatic latent image for development. Thereafter, 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 yellow toner image on the photosensitive drum 1 is primarily transferred onto the intermediate transfer belt 5a. You.
[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. The steps of forming, developing and primary transferring the electrostatic latent image as described above are sequentially repeated for each of the colors magenta (M), cyan (C), and black (Bk), so that the intermediate transfer belt 5 a Are superimposed with toner images of four colors.
[0035]
During this time, the secondary transfer roller 11 is at a position not in contact with the intermediate transfer belt 5a, and the cleaning charging roller 5f as a cleaning unit is also at a position not in contact with the intermediate transfer belt 5a.
[0036]
After the four color toner images are formed on the intermediate transfer belt 5a, the secondary transfer roller 11 is pressed against the intermediate transfer belt 5a as shown in FIG. Further, in synchronization with the rotation of the intermediate transfer belt 5a, the recording medium that has been waiting at a predetermined position near the registration roller pair 7, which is a feeding unit, is sent out 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 that detects the leading end of the recording medium, shuts off the rotational driving force of the registration roller pair 7, and waits the recording medium at a predetermined position is provided. .
[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 5a is collectively and secondarily transferred to the surface of the conveyed recording medium.
[0039]
The recording medium on which the toner image has been secondarily transferred in this manner is conveyed to the fixing device 8 via the conveyance belt unit 12, where the fixing of the toner images of a plurality of colors is performed.
[0040]
The recording medium on which the toner image has been fixed is conveyed along a paper discharge guide 15 by a pair of discharge rollers 13 and discharged to a discharge section 10 above the color image forming apparatus A by a pair of discharge rollers 9 to complete image formation.
[0041]
On the other hand, the cleaning charging roller 5f is pressed against the intermediate transfer belt 5a after the completion of the secondary transfer, and a predetermined bias voltage is applied to the residual toner remaining on the intermediate transfer belt 5a to remove the residual charges.
[0042]
The removed residual toner is electrostatically re-transferred from the intermediate transfer belt 5a to the photosensitive drum 1 via the primary transfer nip, and the surface of the intermediate transfer belt 5a is cleaned.
[0043]
The residual toner remaining on the secondary transfer 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 as waste toner, and is collected and accumulated in the waste toner box 16.
[0045]
(Configuration of developing cartridge)
Next, a schematic configuration of the developing cartridge will be described with reference to FIGS. FIG. 2 is a schematic vertical cross-sectional view of the developing cartridge 4Y (4M, 4C, and 4Bk have the same schematic configuration and will not be described), 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 the present embodiment, four developing devices that can develop each color of yellow, magenta, cyan, and black It is composed of cartridges 4Y, 4M, 4C, 4Bk.
[0047]
In this embodiment, the developing cartridge which is a cartridge type developing unit detachable from the image forming apparatus will be described in detail. However, the present invention is not limited to this configuration. However, the present invention can be suitably applied.
[0048]
As shown in FIGS. 2 and 3, the developing cartridge 4Y has a protective cover 360 detachable from the developing cartridge 4Y for the purpose of protecting the developing roller when the developing roller is not inserted into the image forming apparatus main body.
[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. While being held by the rotary unit 301, the rotary unit 301 is rotated around an axis, a predetermined developing cartridge is stopped 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. After that, a visible image is formed corresponding to the electrostatic latent image on the photosensitive drum 1.
[0050]
At the time of forming a color image, 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 4 </ b> Y sends the toner in the developing container 302 constituting the developing frame to the toner supplying roller 304 by the toner stirring member 303, and rotates the toner supplying roller 304 rotating clockwise in FIG. The developing blade 332 pressed against the outer periphery of the roller 305 applies a thin layer of toner to the outer periphery of the developing roller 305 rotating in the clockwise direction in the drawing, and applies electric charge 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 according to 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]
Each developing roller 305 of each developing cartridge is connected to a high-voltage power supply for each color development and a drive (not shown) provided in the printer main body when each developing cartridge is rotated to the developing position. , A voltage is sequentially and selectively applied to the driving device.
[0054]
Here, the developing cartridge according to the present embodiment is a contact developing system in which the photosensitive drum 1 and the developing roller 305 come into contact with each other to perform development. The photosensitive drum 1 is one in which a photosensitive layer is provided on a metal cylinder made of stainless steel, copper, an aluminum alloy, or the like, and the developing roller 305 in contact with the photosensitive layer is formed by forming an elastic roller on a shaft such as a metal rod.
[0055]
As the elastic body, a solid rubber single layer or a solid rubber layer coated with a resin in consideration of the charging property to the toner is used. Further, the developing blade 332 that presses against the developing roller 305 to form a thin layer of toner on the outer periphery of the developing roller 305 and imparts a charge to the toner (friction charging) has a spring property such as phosphor bronze or stainless steel. It is a thin metal plate or a metal coated with resin on its surface, and comes into contact with 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 of this embodiment with the protective member inserted, and FIG. 6 is a cross-sectional view of the developing cartridge without the protective member inserted.
[0057]
As shown in FIG. 4, the pressure dispersing member 333 a having the function of dispersing the contact pressure of the developing blade 332 with the developing roller 305 is in contact with the protective member 333. One end of the auxiliary member 333b integrally joined to the pressure dispersing member 333a contacts the developing blade 332, and is sandwiched between the developing roller 305 and the developing blade 332 together with the pressure distributing member 333a. The other end of the auxiliary member 333b is joined to the protective cover 360 in the region of the joining layer 333c with a double-sided tape or the like.
[0058]
Therefore, the contact pressure of the developing blade 332 on the developing roller 305 can be dispersed from the time of manufacturing the developing cartridge to the start of use by the user, and the 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 pulled out together, so that it is possible to prevent forgetting to remove the protective member 333 when using the process cartridge.
[0059]
Next, specific examples of the present invention will be described in detail.
[0060]
(Mechanism of pressure dispersion)
First, the mechanism of pressure dispersion will be described. As shown in FIG. 7, when the developing blade 332 contacts 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. Is about 1 mm. As a result, the surface pressure applied to the developing roller 305 is about 19.6 × 10 ³ N / m ² ( ² gf / mm ² ).
[0061]
Thus, as shown in FIG. 8, the pressure dispersing material 333a is compressed and deformed by interposing the pressure dispersing material 333a between the developing roller 305 and the developing blade 332, and the contact width is experimentally expanded to about 3 to 5 mm. The surface pressure of the developing blade 332 on the developing roller 305 is substantially reduced, so that the deformation of the developing roller 305 can be suppressed.
[0062]
(Pressure dispersing material)
Next, details of the pressure dispersing material 333a that can be suitably used in this embodiment will be described. The pressure dispersing material 333a sandwiched between the developing roller 305 and the developing blade 332 preferably has the following functions in addition to the pressure dispersing action.
[0063]
(1) Do not chemically attack other components during storage over time.
[0064]
(2) There should be no fluff due to vibration during transportation.
[0065]
(3) Excellent operability.
[0066]
These conditions are satisfied, and it has been experimentally found that the following two types of configurations are preferably employed.
[0067]
First, as shown in FIG. 5, it was found that urethane foam having a thickness of about 0.5 mm to 2 mm can obtain desirable characteristics in terms of chemical attack, generation of fluff, generation of operability, and the like, as well as pressure dispersibility.
[0068]
When the thickness of the same urethane foam is 2 mm or more, the pull-out property is significantly deteriorated. On the contrary, when the thickness is 0.5 mm or less, the pull-out property is experimentally improved, but the pressure dispersing effect is not sufficiently obtained. Was. Further, a fiber member such as cotton pile having a hair length of about 1.2 mm can experimentally secure the pressure dispersibility, but did not solve the fluff problem.
[0069]
In addition, those which had no effect experimentally were paper, polyethylene terephthalate sheet, etc., each of which had substantially no pressure dispersing action. Therefore, a urethane foam having a thickness of 0.5 to 2 mm as a pressure dispersing material 333a having the above-mentioned pressure dispersing property, not causing chemical attack on other components during storage over time, generating no fluff, and being excellent in operability. Is desirable.
[0070]
Further, as a configuration having the same pressure dispersing means as that of the urethane foam, as shown in FIG. 6, the pressure dispersing member 333a is an integrally molded product made of a resin such as polyethylene or polypropylene.
[0071]
In this case, assuming that the radius of curvature R2 of the cross-sectional shape of the pressure dispersing material 333a on the developing roller side is R1 where the radius of curvature of the developing roller is R1, as shown in FIG. The effect was confirmed.
[0072]
This is because the urethane foam follows the outer diameter shape of the developing roller 305 by compressing and deforming due to the contact of the developing blade 332 to obtain a pressure dispersion effect. The same pressure dispersion effect can be obtained by using a resin such as polyethylene or polypropylene.
[0073]
(Auxiliary member)
The pressure dispersing material 333a using a foaming agent such as urethane foam during the actual sandwiching operation during the assembling operation and the extraction operation by the user has sufficient strength that the frictional resistance with the developing roller 305 or the developing blade 332 is large. I haven't. Therefore, the workability of the pressure dispersing material 333a alone is extremely poor, such as being difficult to insert and pull out.
[0074]
In the case of a molding resin, there is a risk that the developing roller 305 may be touched when the pressure dispersing material 333a is inserted or withdrawn, or that the pressure dispersing material 333a may be forgotten.
[0075]
Therefore, as shown in FIGS. 4 and 5, the auxiliary member 333b is integrally formed. As the auxiliary member 333b, a polyethylene terephthalate sheet having a thickness of about 150 μm is experimentally preferable when the developing blade 332 is a thin metal plate having a spring property such as phosphor bronze or stainless steel and the surface thereof is not coated with a resin.
[0076]
In addition, when the surface of the developing blade 332 is coated with a resin, it is experimentally known that the auxiliary member 333b may damage the surface of the developing blade 332 when the protective member 333 is inserted and removed. In this case, the auxiliary member 333b may be provided with a lubricating effect such as Teflon (registered trademark) or a silicon coat on the contact surface of the auxiliary member 333b with the developing blade 332, and it has been experimentally found that release paper is preferable.
[0077]
Further, in any case, it was experimentally found that setting the auxiliary member 333b closer to the developing blade 332 than the developing roller 305 is preferable in terms of insertion and removal properties.
[0078]
(Integrated with protective cover)
Next, for the purpose of ensuring usability when the user pulls out the protection member 333, the other end of the protection member 333 opposite to the sandwiching portion between the developing blade 332 and the developing roller 305 is integrated with the protection cover 360. Thus, the protective member 333 can be reliably removed without requiring special awareness of the user.
[0079]
(Structure of protective member (joining of members))
As described above, the protection member 333 is based on the pressure dispersing member 333a and the auxiliary member 333b. The pressure dispersing member 333a is inserted into the developing roller 305 in the direction in which the auxiliary member 333b contacts the developing blade 332, and the other end is provided with a protective cover. It is a configuration integrated with 360.
[0080]
In this embodiment, a double-sided tape is used as a joining means of the joining layer 333c as a joining means of the pressure dispersing material 333a and the auxiliary member 333b, and a joining means of the auxiliary member 333b and the protective cover 360. 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. Further, the bonding region is not particularly limited provided that it does not peel.
[0081]
Although the specific embodiment of the present invention has been described above, the present invention is not limited to the above-described color image forming apparatus or the above-described embodiment, and at least the dispersion of the contact pressure of the developing blade 332 to the developing roller 305 is described. Needless to say, the present invention can be applied to a configuration in which the protective member 333 having an effect is sandwiched between the developing blade 332 and the developing roller 305. It is clear that the material does not have a function as a sealing material.
[0082]
【The invention's effect】
As described above, according to the present invention, it is possible to distribute the contact pressure of the developing blade to the developing roller from the time of manufacturing the process cartridge or the developing unit to the time of initial use by the user. By suppressing the deformation of the developing roller due to the contact pressure of the blade with the developing roller, it is possible to provide a good image.
[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 exemplary embodiment.
FIG. 3 is an overall perspective view of a developing cartridge according to the exemplary embodiment.
FIG. 4 is a cross-sectional view of the developing cartridge according to the exemplary embodiment in a state where a protective member is inserted.
FIG. 5 is a detailed sectional view of a protective member (pressure dispersing material: urethane foam) of the present embodiment.
FIG. 6 is a detailed sectional view of a protective member (pressure dispersing material: soft resin) of the present embodiment.
FIG. 7 is a detailed sectional view showing a blade contact state when there is no protective member.
FIG. 8 is a detailed cross-sectional view illustrating a blade contact state when a protection member is provided.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Photosensitive drum 2 Charging device 3 Exposure means 4 Developing devices 4Y, 4M, 4C, 4Bk Developing cartridge (developing unit)
5f Cleaning charging roller 5a Intermediate transfer belt (intermediate transfer member)
Reference Signs List 6 Cleaning blade 7 Registration roller pair 8 Fixing device 9 Discharge roller pair 10 Discharge unit 11 Secondary transfer roller 12 Transport belt unit 13 Discharge roller pair 14 Pre-registration sensor 15 Discharge guide 16 Waste toner box 18 Pickup roller 19 Transport 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 Protective member 333a Pressure dispersing material 333b Auxiliary member 333c Joining layer 360 Protective cover A Color image forming apparatus

Claims (12)

A protection member detachably sandwiched between a developing roller that carries toner and a developing blade that presses against the developing roller and regulates a toner layer carried on the developing roller,
A protection member comprising a pressure dispersing material for dispersing a pressing force of the developing blade against the developing roller. The protection member according to claim 1, wherein the pressure dispersion material is a foam. The protection member according to claim 1, wherein a portion of the pressure dispersing material that contacts the developing roller has a shape substantially equal to an outer diameter of the developing roller. 4. The protective member according to claim 1, wherein a protective cover for protecting the surface of the developing roller exposed to the outside is provided at one end of the auxiliary member provided with the pressure dispersing material. A developing unit attached to the image forming apparatus,
A developing roller for carrying toner,
A developing blade that presses against the developing roller and regulates a toner layer carried on the developing roller;
A protective member that is detachably sandwiched between the developing roller and the developing blade when the developing unit is not used,
Having a toner supply opening and containing a toner,
The developing unit, wherein the protection member includes a pressure dispersing material for dispersing a pressing force of the developing blade against the developing roller. The developing unit according to claim 5, wherein the pressure dispersing material is a foam. 7. The developing unit according to claim 5, wherein the pressure dispersing member has a portion that comes into contact with the developing roller and has a shape substantially equal to an outer diameter of the developing roller. 8. The developing unit according to claim 5, wherein a protective cover for protecting the surface of the developing roller exposed to the outside is provided at one end of the auxiliary member provided with the pressure dispersing material. A process cartridge detachable from the image forming apparatus,
A developing roller for carrying toner,
A developing blade that presses against the developing roller and regulates a toner layer carried on the developing roller;
When the developing cartridge is not used, a protective member that is detachably sandwiched between the developing roller and the developing blade,
Having a toner supply opening and containing a toner,
The process cartridge according to claim 1, wherein the protection member includes a pressure dispersing material for dispersing a pressing force of the developing blade against the developing roller. The process cartridge according to claim 9, wherein the pressure dispersion material is a foam. The process cartridge according to claim 9, wherein a portion of the pressure dispersing material that contacts the developing roller has a shape substantially equal to an outer diameter of the developing roller. 12. The process cartridge according to claim 9, wherein a protective cover for protecting the surface of the developing roller exposed to the outside is provided at one end of the auxiliary member provided with the pressure dispersing material.

Images