JP2005250185A - Process cartridge and image forming apparatus using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a process cartridge in which the accuracy of a blade attached to the process cartridge for cleaning is improved and distortion or deflection of the blade on attaching is suppressed, and to provide an image forming apparatus using the cartridge. <P>SOLUTION: The process cartridge 200 is detachable and attachable to an image forming apparatus 100 and includes a photoreceptor 10, a cleaning blade 22 to remove transfer residual toner on the photoreceptor 10, a holding plate 21 to hold the cleaning blade 22 and to bring the cleaning blade 22 into contact with the photoreceptor 10, and side plates 220, 250 to support either end of the photoreceptor. The side plates 220, 250 have face contact portions 221, 251, respectively, to hold either end of the holding plate 21. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a process cartridge used for image formation by an electrostatic copying process such as a copying machine, a facsimile machine, and a printer, and also relates to an image forming apparatus using the process cartridge.

By adopting a process cartridge that performs a process necessary for image formation with a photoreceptor, for example, integrally supporting process means such as a charging means, a developing means, and a cleaning means, and detachable from the image forming apparatus main body. The image forming apparatus can be continuously used by replacing the process cartridge itself when it is necessary to repair each process means or when the service life is reached. In addition, since only the replacement work is required, the service person can shorten the work time under the user, and in some cases, the user can easily replace the service person without going to the service person. .
In order to form a high-quality image with this image forming apparatus, any process means constituting the process cartridge must be assembled with high accuracy and without distortion in each process main stage. In particular, if the light rubber blade, which is a cleaning means, is not brought into contact with the photoconductor so as not to be distorted, for example, the cleaning will be poor during image formation running, and the black solid portion or the halftone portion will be white on the image. An abnormal image with speckles or rough graininess may occur.

  Therefore, in Patent Document 1, a guide portion for the process cartridge and a guide surface for guiding the rotation determining dowel are provided, respectively, and the protrusion coaxial with the guide portion is sandwiched between the main body engaging member and the abutting portion of the movable body, and the center position is reached. Is determined. The process cartridge is disclosed in which the dowel enters the end of the guide surface against the spring, and the spring and the click and the process cartridge are urged backward with respect to the movable body and the end is urged. In Patent Document 2, an electrophotographic photosensitive drum, process means acting on the electrophotographic photosensitive drum, and a cartridge that is positioned in contact with a positioning portion of the image forming apparatus main body when mounted on the image forming apparatus main body. A detecting portion for operating cartridge detecting means for detecting the mounting of the process cartridge included in the image forming apparatus main body when the process cartridge is mounted at the mounting position with respect to the image forming apparatus main body. A process cartridge having the cartridge side positioning portion or the vicinity thereof is disclosed.

In Patent Document 3, the positioning part of the photosensitive drum and the positioning part of the cartridge frame are separated and arranged coaxially. The positioning portion of the photosensitive drum is made into a hole, the main body drive shaft is fitted, and this fitting backlash is set to 30 μm or less. A process cartridge is disclosed in which a positioning unit is fitted into a main body positioning unit, and a driving system of a photosensitive drum is separated from another driving system having a large load fluctuation, whereby high-precision driving control can be performed.
In Patent Document 4, a bearing member that rotatably supports the developing roller is provided in the vicinity of one end in the axial direction of the developing roller of the developing frame, and a positioning portion that defines the relative position of the magnet roller to the developing roller is provided on the bearing member. A substantially cylindrical projection that is concentric with the developing roller, and a positioning portion for defining the relative position of the developing roller and the photosensitive drum, and the developing roller on the photosensitive drum. A process cartridge is disclosed that provides a receiving surface for pressurization.

In Patent Document 5, an electrophotographic photosensitive member, process means acting on the electrophotographic photosensitive member, a drum flange having a gear portion fixed to an end portion of the electrophotographic photosensitive member, and the drum flange are fixed. A cleaning frame that rotatably supports the electrophotographic photosensitive member, and a process cartridge in which a side surface, an upper surface, and a front surface and a lower surface of the gear portion of the drum flange as viewed from the mounting direction of the process cartridge are covered with a cover member. It is disclosed.
Further, in Patent Document 6, by performing resin bonding, the side cover and the developing device unit are fixed in a state in which a gap in the longitudinal direction before the bonding is maintained, and the photosensitive unit and the developing device unit are twisted or side cover. A process cartridge is disclosed that can eliminate torque increase and rotational unevenness due to deformation.
Patent Document 7 discloses a process cartridge in which the cleaning device is supported by the side plate of the process cartridge, and the positional accuracy can be improved as compared with the conventional art.

JP 2000-132058 A JP 2000-147960 A JP 2001-249604 A JP 2001-201999 A JP-A-10-74031 JP 2003-241619 A Japanese Patent Laid-Open No. 5-134484

However, Patent Documents 1 and 2 improve the accuracy when the process cartridge is mounted on the image forming apparatus, and do not consider the distortion of the process means.
In Patent Document 3, the positioning accuracy of the photosensitive member of the process cartridge with respect to the image forming apparatus is improved, and the process means is not considered so as not to be distorted.
In Patent Document 4, the positioning accuracy of the developing means such as the developing roller of the process cartridge with respect to the image forming apparatus is improved, and the process means is not considered so as not to be distorted.
In Patent Document 5, the positioning accuracy of the process cartridge in the image forming apparatus main body is improved by increasing the rigidity of the side wall of the cleaning frame, and is not considered so as not to cause distortion in the process means. .
Further, Patent Document 6 is a coupling method in which a plurality of resin frame bodies are provided to eliminate torsion caused by fixing between the frame bodies, and is not considered so that distortion does not enter the process means.
In Patent Document 7, the accuracy is improved by supporting the cleaning device by the side plate, but the holding position of each cleaning means (cleaning blade, magnet roller) is not focused, and the configuration is more accurate. Is desired.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a process cartridge and an image forming apparatus using the process cartridge that prevent the process means mounted on the process cartridge from being distorted. It is. A further object of the present invention is to provide a process cartridge that suppresses the occurrence of twisting and bending when the cleaning means is mounted and an image forming apparatus using the process cartridge.

The features of the present invention, which is a means for solving the above problems, are listed below.
1. The process cartridge according to the present invention is a process cartridge that is detachable from the image forming apparatus, includes an image carrier, a cleaning unit that removes transfer residual toner on the image carrier, and the cleaning unit. A first side plate provided with a holding plate for contacting means to the image carrier, a bearing for supporting one shaft of the image carrier, and a first contact surface for contacting the holding plate; And a second side plate provided with a bearing that supports the other shaft of the image carrier and a second contact surface that contacts the holding plate.
2. The process cartridge according to the present invention is further characterized in that the cleaning means is a cleaning blade.
3. The process cartridge according to the present invention is further characterized in that the contact portion is provided in the vicinity of the inner width of the bearing.
4). The process cartridge of the present invention is further characterized in that another process means is attached after the holding plate is attached to the first side plate and the second side plate.

5). Moreover, the process cartridge of the present invention is further characterized in that the process cartridge further comprises an application means for applying a powder lubricant.
6). The process cartridge according to the present invention is further characterized in that the side plate includes a process cartridge frame, and the process cartridge includes a storage portion for storing a powder lubricant in the process cartridge frame.
7). The process cartridge according to the present invention is further characterized in that the coating means includes an elastomer blade in contact with the image carrier.
8). The process cartridge according to the present invention further includes a charging unit that charges the fixed image carrier.

9. An image forming apparatus of the present invention is an image forming apparatus that visualizes an electrostatic latent image formed on an image carrier with toner, and includes an process cartridge that is detachable from the image forming apparatus. An image carrier, a cleaning unit that removes transfer residual toner on the image carrier, a holding plate that holds the cleaning unit and contacts the cleaning unit with the image carrier, and one of the image carriers. A first side plate provided with a bearing that supports the shaft, a first contact surface that contacts the holding plate, a bearing that supports the other shaft of the image carrier, and a first side plate that contacts the holding plate. And a second side plate provided with two contact surfaces.
10. The image forming apparatus of the present invention further includes the process cartridge described in any one of 2 to 8 above.
11. Further, in the image forming apparatus of the present invention, the toner used in the developing unit has a volume average particle diameter of 3 to 8 μm and a ratio (Dv) of the volume average particle diameter (Dv) to the number average particle diameter (Dn). / Dn) is in the range of 1.00 to 1.40.
12 The image forming apparatus of the present invention is further characterized in that the toner used in the developing means has a shape factor SF-1 in the range of 100 to 180 and a shape factor SF-2 in the range of 100 to 180. And

The process cartridge of the present invention can provide a process cartridge in which the cleaning means can be accurately attached to the image carrier by the means for solving the above problem, and by preventing the cleaning blade from being twisted, This is advantageous in that it is possible to suppress the occurrence of defective cleaning during the image forming operation.
In the image forming apparatus of the present invention, the use of this process cartridge can improve the mounting accuracy of other process modules, and can provide an effect that a high-quality image can be obtained over a long period of time.

The best mode for carrying out the present invention will be described below with reference to the drawings. The following description is the best mode of the present invention and does not limit the scope of the claims.
FIG. 1 is a cross-sectional view illustrating an example of an image forming apparatus that forms a full-color image. The image forming apparatus 100 shown here includes four process cartridges 200 (Y, C, M, K) arranged in parallel in the main body, an endless intermediate transfer belt 62, a secondary transfer roller 65 (in FIG. 1). Add the figure number), and each color toner bottle 59 for supplying toner to the process cartridge. The process cartridge 200 includes an image carrier 10, a cleaning module 20 as a cleaning unit, a charging module 30 as a charging unit, a developing module 50 as a developing unit, and the like.
The intermediate transfer belt 62 is positioned above the photoconductor 10 as each image carrier, and the lower running side of the intermediate transfer belt 62 is in contact with the circumferential surface of each photoconductor 10. The intermediate transfer belt 62 constitutes an example of a transfer material onto which toner images of different colors formed on the surface of each photoconductor 10 are transferred in a superimposed manner.
The configuration in which a toner image is formed on each photoconductor 10 and the toner image is transferred to the intermediate transfer belt 62 is substantially the same except that the color of the toner image is different.
The photoconductor 10 is rotated in the clockwise direction in FIG. 2, and at this time, the photoconductor 10 is charged to a predetermined polarity by a charging module 30 which is a charging unit to which a charging voltage is applied. The photoconductor 10 after charging is irradiated with a light-modulated laser beam L emitted from the optical writing device 40 shown in FIG. 1, whereby an electrostatic latent image is formed on the photoconductor 10. The electrostatic latent image is visualized as a toner image of each color by the developing module 50 as developing means.
A primary transfer roller 61 is disposed on the opposite side of the photoconductor 10 with the intermediate transfer belt 62 interposed therebetween. When a transfer voltage is applied to the primary transfer roller 61, the toner image on the photoconductor 10 is rotated in the middle. Primary transfer is performed on the transfer belt 62. The transfer residual toner adhering to the photoreceptor 10 after the toner image transfer is removed by a cleaning module 20 which is a cleaning unit. On the downstream side of the cleaning means, there is provided a lubricant applying means 70 for applying a lubricant on the photoreceptor 10 to reduce wear on the surface of the photoreceptor 10 and to improve the cleaning performance.
As shown in FIG. 1, a paper feeding device 130 having a paper feeding cassette containing a recording medium made of transfer paper, for example, is disposed in the lower part of the image forming apparatus main body 100, and the intermediate transfer belt 62 is placed at a predetermined timing. The sheet is fed between the portion and the secondary transfer roller 65 opposed to the portion. At this time, a predetermined transfer voltage is applied to the secondary transfer roller 65 from a power source (not shown), whereby the composite toner image on the intermediate transfer belt 62 is secondarily transferred to the recording medium.
The recording medium onto which the composite toner image has been secondarily transferred is further conveyed upward and passes through the fixing device 90. At this time, the toner image on the recording medium is fixed by the action of heat and pressure. The recording medium that has passed through the fixing device 90 is discharged to a paper discharge unit at the top of the image forming apparatus main body 100 by a paper discharge roller pair.

  As in this embodiment, each process means such as a cleaning means, a charging means, and a developing means is modularized so that each process module can be replaced in a module unit with the process cartridge removed from the image forming apparatus main body. The waste of resources due to the disposal of the process means that can still be used with the life of the process cartridge can be prevented. According to the present embodiment, the user or service person can exchange the process cartridge unit or the process module unit, which is very convenient.

  FIG. 2 is a schematic cross-sectional view showing a configuration of a process cartridge according to an embodiment of the present invention. As shown in FIG. 2, the process cartridge 200 includes at least a photosensitive member 10 as an image carrier and a cleaning blade 22 as a cleaning unit in a process cartridge frame (hereinafter, sometimes referred to as “frame”) 210. And. The cleaning blade 22 is integrated with a holding plate 21, an entrance seal 23, a housing 26, and the like, which will be described later, and is configured as a cleaning module 20.

FIG. 3 is a schematic view showing the structure of the process cartridge frame.
The process cartridge frame 210 is integrally provided in the longitudinal direction of the photosensitive member 10 from the side plate 220 (first side plate) on the front side in the figure, and includes a positioning plate 211 to which the charging module 30 is attached, the coating means 70 and the powder. It is comprised with the lubricant storage part 270 which stores a lubricant. The first side plate 220 includes a bearing 222244 for supporting the rotating shaft 14 of the photosensitive member protruding from the flange 13 of the photosensitive member 10, a guide groove 223 for mounting the developing module 50, a fixing hole 225 for fixing the developing module 50, 226 is provided. In addition, a temporary placement portion 232 for temporarily placing the photoconductor 10 when the rotating shaft 14 of the photoconductor 10 is assembled to the side plate 250 is provided on the back side. Further, the first side plate 220 is provided with a first abutting surface abutting portion 221 as an abutting portion for abutting a holding plate 21 of a cleaning unit described later.

  FIG. 4 is a schematic view showing a side plate 250 (second side plate) attached to the back side of the process cartridge frame 210. The second side plate 250 includes a second abutting surface abutting portion 251 as an abutting portion for abutting the holding plate 21 of the cleaning module 20, a bearing 256 through which the rotating shaft 14 of the photoreceptor 10 passes, and this bearing 256. A bearing hole 252 for providing, a shaft support 253 into which the shaft 511 of the developing sleeve 51 is inserted, and a guide groove 255 for guiding the supply roller 54 are formed. The fixed hole hole 254 protrudes from the lubricant accommodating portion 270 of the process cartridge frame 210 and protrudes from the powder lubricant supply port 290. The first contact surface contact portion 221 of the side plate 220 and the second contact surface contact portion 251 of the second side plate 250 described above contact the holding plate 21 of the cleaning module 20 to the photosensitive member 10. The angle is determined.

FIG. 5 is a schematic view showing the front side of the photoconductor 10 arranged in the process cartridge 200.
As shown in FIG. 5, the photoreceptor 10, which is a cylindrical image carrier, is provided with flanges 13 and 15 at both ends inside the cylinder, and a rotating shaft 14 that penetrates both flanges.

  FIG. 6 is a schematic view showing the structure of the photosensitive layer of the photoreceptor. As shown in FIG. 6, the photoreceptor 10 is provided with a photosensitive layer 12 on a cylindrical aluminum substrate 11. The substrate 11 of the photoreceptor 10 is subjected to surface treatment such as cutting, superfinishing, and polishing after extruding a metal such as aluminum, copper, iron, or an alloy thereof, and processing such as drawing to form a cylindrical blank. It is formed in a cylindrical drum. The structure of the photosensitive layer 12 includes a charge generation layer 121 that is a layer mainly composed of a charge generation material and a charge transport layer 122 that transports the generated charges to the surface of the photoreceptor or the substrate 11. In the charge generation layer 121, a charge generation material is dispersed in a suitable solvent together with a binder resin as necessary using a ball mill, an attritor, a sand mill, an ultrasonic wave, etc., and this is applied onto a conductive support. It is formed by drying. A known charge generation material can be used for the charge generation layer 121, and representative examples thereof include monoazo pigments, disazo pigments, trisazo pigments, perylene pigments, perinone pigments, quinacridone pigments, and quinone condensation polymers. Examples thereof include ring compounds, squalic acid dyes, phthalocyanine pigments, naphthalocyanine pigments, and azulenium salt dyes. Of these, azo pigments and / or phthalocyanine pigments are effectively used.

  The charge transport layer 122 can be formed by dissolving or dispersing a charge transport material and a binder resin in a suitable solvent, and applying and drying the solution on the charge generation layer. Moreover, a plasticizer, a leveling agent, antioxidant, etc. can also be added as needed. Charge transport materials include hole transport materials and electron transport materials. Examples of the charge transporting material include chloroanil, bromineyl, tetracyanoethylene, and examples of the hole transporting material include poly-N-vinylcarbazole and derivatives thereof, poly-γ-carbazolylethyl glutamate and derivatives thereof, and pyrene-formaldehyde condensates. And derivatives thereof, polyvinylpyrene, and polyvinylphenanthrene. In addition, a protective layer 123 may be provided on the photosensitive layer 12 in order to protect the photosensitive layer 12. In addition, a filler can be added to the protective layer 123 for the purpose of improving the wear resistance. In particular, it is advantageous to use an inorganic material among them from the viewpoint of the hardness of the filler. In particular, silica, titanium oxide, and alumina can be used effectively.

7A and 7B are schematic perspective views of the cleaning module 20 used in the process cartridge of the present invention. FIG. 7A is an external perspective view, and FIG. 7B is a cross-sectional view.
As shown in FIG. 7, the cleaning module 20 includes a cleaning blade 22 that is a cleaning means, a holding plate 21 that holds the cleaning blade, an entrance seal 23 that seals the inside of the housing 26 so that the toner collected from the photosensitive member is not scattered, and is collected. A housing 26 for storing the toner and a transport auger 25 for transporting the toner collected in the housing 26 into the main body of the image forming apparatus 100 are provided. The holding plate 21 has a housing 26 fixed thereto with screws 27 at a substantially intermediate position in the longitudinal direction.
Further, on both sides of the holding plate 21, as positioning guides 28, there are provided hole portions 281 corresponding to positioning bar-shaped protrusions provided on the contact surface contact portions 221, 251 and holes 282 for fixing screws. . Note that the positioning is not limited to this, and for example, an elastic member may be pressed against a hole or a recessed portion. Further, the fixing is not limited to the screw, and an E-ring or the like may be used for the rod-shaped protrusion.

  FIG. 8 is a schematic view schematically showing the arrangement state of the cleaning blade of the present invention. In the present invention, the cleaning blade 22 is fixed to the holding plate 21 as shown in (A), with respect to the holding plate 21 that holds the cleaning blade 22, the contact surface contact portion 221 that contacts the holding plate 21, 251 are arranged in the same direction. However, as shown in (B), the contact surface abutting portions 221 and 251 that abut the holding plate 21 may be disposed in the opposite direction to the holding plate 21 that holds the cleaning blade 22. However, in this embodiment, by adopting the fixing direction of the cleaning blade 22 shown in (A), the thickness of the adhesive or the like for fixing the cleaning blade, the thickness of the holding plate 21, and the thickness of the cleaning blade 22 itself are set. Due to the fluctuation, the fluctuation of the state of the cleaning blade 22 in contact with the photosensitive member 10 can be ignored, so that the distortion of the contact state of the cleaning blade 22 can be eliminated, and the occurrence of defective cleaning can be suppressed.

The cleaning blade 22 is made of an elastomer including fluorine rubber, silicone rubber, urethane rubber, or the like. In particular, urethane elastomer is preferable from the viewpoints of wear resistance, ozone resistance, and contamination resistance. Further, the holding plate 21 has an L-shaped cross section in order to suppress bending caused by pressing the cleaning blade 22 onto the photosensitive member and reduce distortion.
The material is made of a SUS steel plate having a thickness of 2.0 mm and has strength. The holding plate 21 may be a copper plate such as an iron plate, an aluminum plate, or phosphor bronze.
In addition, the cleaning blade 22 is fixed to the holding plate 21 by applying an adhesive to the holding portion 21 and bonding it by heating or pressing. However, fixing with a double-sided tape or an adhesive can also be employed for convenience.

FIG. 9 is a schematic diagram showing contact conditions of the cleaning blade. The contact method of the cleaning blade 22 of this embodiment employs a counter method in which the blade contacts the counter with respect to the rotation direction of the photosensitive member, but is a trailing method in which the blade contacts in the forward direction with respect to the rotation direction. There may be. In particular, the counter system is preferable. Even if the contact pressure against the photoconductor 10 is small, the cleaning property is high. In addition, the photoconductor 10 is less worn.
The cleaning blade 22 preferably has a hardness (JIS-A) in the range of 6560 to 85 °. If the hardness is less than 6560 °, the cleaning blade 22 is greatly deformed and it becomes difficult to clean the toner or the like. If the hardness exceeds 85 °, the photoconductor 10 is abraded and the life of the image forming apparatus is shortened. Further, the contact pressure of the cleaning blade 22 is preferably in the range of 10 to 60 gf / cm. If the contact pressure is less than 10 gf / cm, it is difficult to clean the toner having a particle size of less than 2 μm. If the contact pressure exceeds 60 gf / cm, the tip of the cleaning blade 22 is likely to be turned up or bound, resulting in poor cleaning such as chatter. It becomes easy and the cleaning property decreases. The elastic modulus of the cleaning blade is 4.5 to 10 MPa, the free length of the cleaning blade 22 is 5 to 12 mm, the thickness of the cleaning blade 22 is 1 to 2 mm, the contact angle is 5 to 25 degrees, and the biting amount is 0.1 to 2.0 mm is preferred. The contact angle of the cleaning blade 22 is preferably in the range of 5 to 25 ° or less from the tangent line of the contact position. If the contact angle is less than 5 °, cleaning failure due to toner slippage tends to occur, and if it exceeds 25 °, the blade may be turned up during cleaning. The amount of biting of the cleaning blade 22 into the photoreceptor 10 is preferably in the range of 0.1 to 2.0 mm. If the thickness is less than 0.1 mm, the contact area between the cleaning blade 22 and the photosensitive member 10 is small, resulting in poor cleaning through which the toner slips. If the thickness exceeds 2.0 mm, the frictional force with the photosensitive member 10 increases and the blade is turned or bounded. It becomes easy. In addition, cleaning defects such as squeal and chatter due to blade vibration occur.

  FIG. 10 is a schematic view showing the developing module. A cross-sectional view thereof is shown in FIG. As shown in FIG. 2, in the developing module 50, a developing sleeve 51 that is a developer carrying member disposed so as to be close to the photosensitive member 10, a toner bottle provided outside the process cartridge 200, and a supply unit A replenishment port (not shown) for replenishing toner to the developing module 50 containing the developer, a mixing screw 53 for mixing and stirring the replenished toner with the magnetic carrier, and 54 for supplying the mixed developer to the developing sleeve A regulating member 55 that regulates the amount of developer supplied to the roller 54 and the developing sleeve 51 is disposed. As shown in FIG. 10, the developing module 50 includes a rotating shaft 511 for rotating the developing sleeve 51, a guide 521 provided in a protruding shape on the top and bottom of the developing module main body for positioning when mounted on the process cartridge 200, 522, a partition plate 561 that prevents leakage of the developer during conveyance to the outside, and a developer storage unit 56 that stores the developer by partitioning with the partition plate 561 are provided. By sealing with a partition plate 561 provided in the developer storage portion 56 for storing the developer, leakage of the developer at the time of transport is prevented, and the partition plate 561 is pulled and removed at the first use to open the container. Then, the developer is supplied from the developer container 56 to the mixing / stirring screw 53.

In the developing sleeve 51, a developing sleeve formed of a non-magnetic material such as aluminum, brass, stainless steel, or conductive resin in a cylindrical shape is rotated by a rotation driving mechanism, so that the developer is conveyed by a magnetic pole provided inside. It has come to be. The height of the developer chain spike, that is, the amount of developer on the developing sleeve 51 is regulated by a regulating member 55 arranged in the upstream portion of the developing area in the developer transport direction.
In addition to the two-component developer using a magnetic carrier and toner, a magnetic one-component developer and a non-magnetic one-component developer can be appropriately selected and used as the developer. In this case, the specifications of the developing sleeve are changed. It can respond.

FIG. 11 is a schematic view showing a face plate for positioning and fixing the developing module to the process cartridge.
The face plate 240 is fitted to the outer periphery of a bearing 222244 that supports the rotating shaft 14 of the photoconductor 10, and a hole 241 positioned with respect to the shaft of the photoconductor and the shaft 511 of the developing sleeve 51 of the developing module 50 are inserted. A screw hole 243 for fixing the insertion portion 242 and the face plate 240 to the side plate 220 of the process cartridge frame 210 is provided.
FIG. 12 is a diagram showing a state when the developing module is positioned by the face plate with respect to the side plate on the front side of the process cartridge frame. As shown in FIG. 12, the rotating shaft 14 of the photosensitive member 10 is positioned by passing through a bearing 222244 provided on the side plate 220 of the process cartridge frame 210. In the face plate 240, the positioning hole 241 is fitted to the outer periphery of the bearing 244, and the insertion portion 242 is inserted into the shaft 511 of the developing sleeve 51, whereby the position of the rotating shaft 14 of the photosensitive member 10 and the developing sleeve 51 is changed. It is determined. After such positioning, the guides 521 and 522 of the developing module 50 are fixed from the fixing holes 225 and 226, respectively, and the developing module 50 is fixed to the frame.

FIG. 13 is an assembly diagram of a process cartridge according to an embodiment of the present invention. The process cartridge 200 according to the present invention is an assembly in which the photosensitive member and the cleaning blade 22 are assembled to at least the process cartridge frame 210 by using the side plate 250 attached to the process cartridge frame 210. 26 can be assembled at the same time.
As shown in FIG. 13, the shaft 14 of the photoconductor 10 is inserted into the bearing 222244 provided on the side plate 220 in the process cartridge frame 210, and the shaft 14 of the photoconductor 10 is inserted into the bearing 256 of the second side plate 250. Then, the process cartridge frame 210 is fixed to the side plate 230. Further, the guide portion 28 provided on the holding plate 21 that holds the cleaning blade 22 is positioned on the first contact portion 221 and the second contact portion 251 provided on the side plate 220 and the second side plate 250 of the process cartridge frame 210, respectively. And attach. This enables highly accurate positioning, twisting, and flexure mounting with fewer parts, and prevents distortion from entering the process cartridge frame 210, so that each module during image formation maintains high accuracy. It can be operated as it is.
Hereinafter, the mounting of each module and part will be described in detail.

  FIG. 14 is a diagram showing a state in which the photoconductor is mounted on the second side plate and attached to the inner side of the frame. After the rotating shaft 14 of the photoconductor 10 is inserted and positioned in the bearing 256 of the second side plate 250, the coupling 141 is attached to the end of the rotating shaft 14. When the process cartridge 200 is mounted, the coupling 141 is engaged with a driving unit (not shown) provided on the main body side of the image forming apparatus 100, and the photosensitive member 10 is rotationally driven. In the cleaning module 20, the holding plate 21 is brought into contact with the contact surface contact portion 251 of the side plate 250, guided by the guide 281 as described above, and fixed by the fixing hole 282. Further, it is fixed to the side plate 250 by the fixing means 257. At this time, a supply port 290 for supplying powder lubricant protrudes from the hole 254. Further, in the developing module 50, the shaft 511 of the developing sleeve 51 is inserted from the shaft support portion 253, and the supply roller 54 is guided by the guide groove 255 to be fixed to the side plate 250.

  As described above, the first contact surface contact portion 221 provided on the first side plate 220 and the second contact surface contact portion 251 provided on the second side plate 250 include the holding plate of the cleaning module 20. In order to fix 21, a positioning projection and a screw hole are provided. Accordingly, since the holding plate 21 can be supported at both ends of the process cartridge, that is, as long as possible in the longitudinal direction, the holding plate 21 can be stably held, and the cleaning blade 22 attached to the holding plate 21 and the photosensitive member 10 can be supported. The contact state can be attached with high accuracy. The bearings 244 and 254 that support the rotating shaft 14 of the photoconductor 10 are both the first contact surface contact portion 221 and the second contact surface contact portion 251, respectively. The holding plate 21 is fixed toward the bearings 222 and 256 within the width of the bearings 222 and 256 that support the bearings and in the vicinity thereof. Accordingly, the distance and angle accuracy with respect to the rotation axis of the photosensitive member supported by the holding plate 21 and the bearing can be increased. As a result, the contact between the cleaning blade 22 held by the holding plate 21 and the photosensitive member 10 can be improved. The contact state can be attached with high accuracy and the occurrence of distortion can be suppressed. Further, as described above, the use of a high-strength material (a steel plate having a thickness of 2.0 mm in the present embodiment) for the holding plate 21 prevents the generation of strain.

The holding plate 21 is preferably made of metal to increase the rigidity. Accordingly, the distortion generated when the holding plate 21 of the cleaning blade 22 is fixed at both ends can be regulated from the size of the first side plate 220, the second side plate 250, the process cartridge frame 210, and the like. Further, as in the present embodiment, it is preferable that the first side plate 220 and the second side plate 250 that support the holding plate 21 are separate members. By using a separate member, it is possible to reduce the influence of the strain from the molding that occurs when the two members are integrated, and the positions of the side plates 220 and 250 are based on the holding plate 21 that is higher in rigidity than the frame. Decrease the distortion of the process cartridge itself. It can be assembled with high accuracy. In addition, if the developing module 50 and the charging module 30 are attached after the cleaning module 20 is attached to the process cartridge 200 by the highly rigid holding plate 21, the influence of distortion due to the attachment of the cleaning module 20 is reduced. Therefore, as a result, it is possible to prevent the occurrence of distortion in the mounting of the developing module 50 and the charging module 30 and to perform with high accuracy.
Further, when the cleaning module 20 is mounted on the process cartridge frame 210, even if the cleaning blade 22 and the photosensitive member 10 are brought into contact with high accuracy, a force that rotates around the holding plate 21 acts. For this reason, in order to suppress the rotation of the cleaning module 20, a fixing member 257 for fixing the process module 200 or the face plates 240 and 250 to the cleaning module 20 is further provided. The fixing member 257 may be fixed with a screw, a pin, or the like.

FIG. 15 is a schematic cross-sectional view showing a lubricant application device. As shown in FIGS. 2 and 15, the lubricant application device 70 is provided separately from the cleaning module 20, and forms a film forming member 71 for thinning the lubricant on the photoreceptor 10, and uses the lubricant as the photoreceptor. 10, a supply member 722 including a supply roller 722 that is driven to rotate forward in the rotation direction of the photoconductor 10 and supplies a lubricant onto the photoconductor, and a process cartridge frame 210. It comprises a lubricant storage part 270 for storing a lubricant. In addition, the supply member 722 is not limited to the configuration, and can be conveniently employed by providing a brush on the surface of the metal roller. The film 721 is selected from polyester resin, fluororesin, styrene resin, and acrylic resin. For the brush, a polyamide resin such as nylon that is strong against abrasion and high in strength can be used in addition to the same resin. In order to prevent frictional charging, the conductive powder may include carbon black such as acetylene black and furnace black, graphite, or conductive powder of metal powder such as copper and silver. Specifically, the electrical resistance is preferably in the range of 10 ² to 10 ⁸ Ω · cm. The film forming member 71 includes a coating blade 711 and a blade support member 712. The coating blade 711 uses a fluorine resin, urethane resin, or silicone resin elastomer in a blade shape. In particular, a urethane resin having high elasticity and being hard to be worn is preferable. The blade support member 712 is provided with a foam that supports the coating blade 711, and a foam made of silicone resin, fluorine resin, or urethane resin is used. In particular, urethane foam is preferable. As a result, it is possible to suppress wear caused by excessively pressing the photoreceptor 10 and to form a uniform film of lubricant.

Regarding the contact condition of the coating blade 711, the method of contacting the photoconductor 10 may be a counter method or a trailing method. There is little generation of curling by the blade, and the lubricant can be uniformly thinned. The contact pressure is 5 to 30 N / m, and the contact angle is 10 to 30 °. Other conditions such as the amount of biting can be appropriately determined depending on the elastic modulus of the blade. However, the lubricant having low hardness is thinned, and the contact pressure or the like is made lower than the contact condition of the cleaning blade 22 in cleaning.
In the coating device 70, the supply member 72 puts the lubricant in the lubricant storage portion 270 on the film 721 of the supply roller member 722, supplies the lubricant to the photoconductor 10, and is applied in contact with the photoconductor 10. The lubricant is thinned with a blade 711 and applied. As a result, the coefficient of friction of the photoconductor 10 can be lowered, the toner transfer rate can be improved, and the amount of toner to be discarded can be reduced.
Further, by reducing the coefficient of friction of the surface of the photoconductor 10, even spherical toner that is difficult to clean can be cleaned. Further, by forming the thin layer of the lubricant with the coating blade 711, unnecessary lubricant is blocked by the coating blade 711, and the film having the minimum thickness is formed by reducing the amount of the thin film formed on the photoreceptor 10 as much as possible. Can be formed. At this time, the lubricant that has not become a thin layer spills from the application blade 711 and returns to the lubricant storage portion 270, so that the lubricant can be used for a long time.

Examples of the lubricant include fatty acid metals such as lead oleate, zinc oleate, copper oleate, zinc stearate, cobalt stearate, iron stearate, copper stearate, zinc palmitate, copper palmitate and zinc linolenate. Fluorine such as salts, polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinylidene fluoride, polytrifluorochloroethylene, dichlorodifluoroethylene, tetrafluoroethylene-ethylene copolymer, tetrafluoroethylene-oxafluoropropylene copolymer Based resins. In particular, fatty acid metal salts having a large effect of reducing the friction of the photoconductor 10, and stearic acid as a fatty acid, zinc stearate using calcium or calcium as a metal, and calcium stearate are more preferable.
The lubricant used is in the form of powder and has a volume average particle size in the range of 0.1 to 3.0 mm. The molded lubricant must be rubbed strongly with a brush and scraped into a powder form to be supplied to the photoconductor 10. This shortens the life of the brush and increases the strength of the shaft and gear for driving. It is difficult to reduce manufacturing costs. By using a powdery lubricant, the service life of the supply member 72 can be extended and the use period of the coating apparatus 70 can be extended. Further, by reducing the volume average particle diameter of the powdery lubricant, it is possible to facilitate the thinning with the coating blade 711. If it is less than 0.1 mm, the coating blade 711 passes through without being thinned. If it exceeds 3.0 mm, it is cleaned by the coating blade 711 and cannot be thinned.

16A and 16B are schematic views showing the configuration of the charging module, where FIG. 16A is an external perspective view, and FIG. 16B is an external side view.
As shown in FIG. 16, the charging module 30 is configured to vibrate the charging member 31 disposed facing the photoconductor 10, the gear 37 (not shown) fixed to the end of the charging member 31, and the charging member 31. The spring material 32 to prevent, the charging cleaning roller 33 to remove the dirt of the charging member 31, the bearing 37 of the cleaning roller 33, the spring material 38 to press the charging cleaning roller 33 so as to contact the charging member 31, and the gap between the photosensitive member 10. And a support member 35 for supporting the charging member 31 on the housing of the charging module 30 and a housing 39 for storing them. The gear 37 of the charging member 31 is rotationally driven by a driving mechanism described later, and the charging cleaning roller 33 is rotatably supported so as to rotate with the charging member 31. The support member 35 is pressed by the spring material 32 in a direction away from the housing 39 (a direction toward the drum shaft of the photosensitive member), and movement of the support member 35 is restricted by a restriction member formed on the housing 39. With this configuration, when the charging module 30 is mounted on the process cartridge 200, the charging member 31 maintains an appropriate distance from the photoconductor 10 by the spacer member 34, and prevents the charging member 31 from vibrating. Further, when the charging module 30 is removed, the charging module 30 itself can be handled.
Further, although the charging member 31 is driven by the driving mechanism, the charging member 31 may be configured to be driven by driving of the photoconductor 10.

  FIG. 17 is a schematic diagram showing the biasing position of the spring material of the charging module before being attached to the process cartridge. As shown in the drawing, the charging cleaning roller 33 is biased by the spring material 38 in the direction in which the charging member 31 is biased by the spring material 32 and restricted in the housing by a distance X from the rotation center of the charging member 31. It's off. Therefore, deformation due to the charging cleaning roller 33 being pressed against the charging member 31 before the charging module 30 is attached is reduced. In addition, after the charging module 30 is attached, the charging member 31 is pressed against the photosensitive member 10 and the spring member 32 is contracted, so that the charging cleaning roller 33 is urged toward the rotation center of the charging member 31. . Accordingly, the charging cleaning roller 33 and the charging member 31 are appropriately brought into contact with each other, and the cleaning property is improved.

FIG. 1821 is a schematic view showing the structure of the charging member. FIG. 18 is a schematic view showing the structure of the charging member. In the charging module 30, the charging member 31 can be configured in an appropriate form, but a roller shape is preferable. The charging roller 31 has a structure including a main body portion 312 having a shaft portion 311 made of a metal core at the center, an intermediate resistance layer 313 on the outer side, and a surface layer 314 on the outermost layer. The shaft portion 311 is made of, for example, stainless steel having a diameter of 8 to 20 mm, aluminum having high rigidity and conductivity, or 1 × 10 ³ Ω · cm or less, preferably 1 × 10 ² Ω · cm or less. It is made of conductive resin having high rigidity. The middle resistance layer 313 preferably has a volume resistivity of 1 × 10 ⁵ Ω · cm to 1 × 10 ⁹ Ω · cm and a thickness of about 1 to 2 mm. The surface layer 314 has a volume resistivity of 1 × 10 ⁶ Ω · cm to 1 × 10 ¹² Ω · cm, and preferably has a thickness of about 10 μm. The volume resistivity of the surface layer 314 is preferably higher than the electrical resistivity of the medium resistance layer 313. Here, the main body 312 is shown as a two-layer structure of the intermediate resistance layer 313 and the surface layer 31, but is not particularly limited to this structure, and may be a single layer or three layers.
The charging cleaning roller 33 employs a resin foam such as melamine foam, but may be cleaned with a brush or roller.

  The gap between the charging roller 31 and the photoreceptor 10 is set to 100 μm or less, particularly 20 to 50 μm, by the spacer member 34. Thereby, formation of an abnormal image at the time of the operation of the charging module 30 can be suppressed. The gap may be adjusted by providing a fitting portion in the process cartridge frame 210 that fixes the process cartridge 200 and the charging module 30. The charging roller 31 is pressed toward the surface of the photoreceptor 10 by a spring material 32 provided on a bearing made of a resin having a low friction coefficient. As a result, a constant gap can be formed even if there is mechanical vibration or deviation of the cored bar.

FIG. 19 is a schematic view showing a gear train provided inside the side plate. As described above, the photoconductor 10 is rotationally driven from the apparatus main body. The rotation of the photoconductor gear 10a provided on the rotation shaft 14 of the photoconductor 10 is transmitted by the transfer auger gears 25a, 25b, and 25c to rotate the transfer auger 25. The transport auger 25 is driven to rotate to transport the collected toner collected in the housing 26 of the cleaning module 20 to the outside of the process cartridge. Further, the rotation of the photoconductor gear 10a is transmitted by the supply members 72a, 72b, and 72c, and the supply member 72 is rotationally driven to supply the lubricant to the surface of the photoconductor 10. Further, the rotation of the photoconductor gear 10a is transmitted by the charging member gears 37a and 37b, and the charging member 37 is rotationally driven to uniformly charge the surface of the photoconductor 10.
In this embodiment, the rotation speed of the supply member 72 that supplies the lubricant is set to be faster than the rotation speed of the photoconductor 10. Therefore, the amount of lubricant applied to the surface of the photoreceptor 10 is not insufficient. However, by adjusting the gear ratio, the rotational speed of the photoreceptor and the rotational speed of the supply member can be adjusted, and the lubricant application amount can be set appropriately.

  In addition, the process cartridge 200 includes a temperature / humidity sensor for detecting the temperature and humidity in the process cartridge 200, a potential sensor for detecting the potential of the photoconductor 10, and the developed photoconductor 10 as detection means. A toner density sensor for detecting the amount of toner developed above can be provided. Further, for example, a pre-transfer static eliminator and a pre-cleaning static eliminator may be provided.

The process cartridge 200 of the present invention is a process cartridge 200 that can be attached to and detached from the image forming apparatus 100 with at least the photosensitive member 10 and a cleaning blade 21 as a cleaning unit integrally supported. In the process cartridge 200, the mounting accuracy of the cleaning blade 21 can be increased, the cleaning performance can be improved, and the occurrence of cleaning failure can be delayed. Further, by increasing the mounting accuracy of the cleaning blade 21 and reducing distortion, the accuracy in mounting other process modules can be increased. The mounting of the developing module 50, the photosensitive member 10, the developing module 50, and the like. The accuracy of the gap can be increased, and a high-quality image can be obtained. Further, by increasing the accuracy of the gap between the photoconductor 10 and the charging module 30, it is possible to extend the life of the photoconductor 10 by suppressing the generation of ozone and discharge products. Further, by preventing distortion when the cleaning blade 21 is mounted, it is possible to suppress the occurrence of abnormal noise such as turning of the blade and chatter during image formation.
Further, in the image forming apparatus 100 of the present invention, by using such a process cartridge 200, a high-quality image can be stably supplied over a long period of time.

  Next, toner that is preferably used in the image forming apparatus 100 of the present invention will be described. In order to reproduce minute dots of 600 dpi or more, the toner preferably has a volume average particle diameter of 3 to 8 μm. The ratio (Dv / Dn) of the volume average particle diameter (Dv) to the number average particle diameter (Dn) is preferably in the range of 1.00 to 1.40. The closer (Dv / Dn) is to 1.00, the sharper the particle size distribution. With such a toner having a small particle size and a narrow particle size distribution, the toner charge amount distribution is uniform, a high-quality image with little background fogging can be obtained, and the electrostatic transfer method has a high transfer rate. can do.

The toner shape factor SF-1 is preferably in the range of 100 to 180, and the shape factor SF-2 is preferably in the range of 100 to 180. FIG. 20 is a diagram schematically showing the shape of the toner in order to explain the shape factor SF-1 and the shape factor SF-2. The shape factor SF-1 indicates the ratio of the roundness of the toner shape and is represented by the following formula (1). This is a value obtained by dividing the square of the maximum length MXLNG of the shape formed by projecting the toner on a two-dimensional plane by the figure area AREA and multiplying by 100π / 4.
SF-1 = {(MXLNG) 2 / AREA} × (100π / 4) Formula (1)
When the value of SF-1 is 100, the shape of the toner becomes a true sphere, and becomes larger as the value of SF-1 increases.
The shape factor SF-2 indicates the ratio of the unevenness of the toner shape, and is represented by the following formula (2). A value obtained by dividing the square of the perimeter PERI of the figure formed by projecting the toner onto the two-dimensional plane by the figure area AREA and multiplying by 100 / 4π.
SF-2 = {(PERI) 2 / AREA} × (100 / 4π) (2)
When the value of SF-2 is 100, there is no unevenness on the toner surface, and as the value of SF-2 increases, the unevenness of the toner surface becomes more prominent.
Specifically, the shape factor is measured by taking a photograph of the toner with a scanning electron microscope (S-800: manufactured by Hitachi, Ltd.), introducing it into an image analyzer (LUSEX 3: manufactured by Nireco) and analyzing it. Calculated.
When the shape of the toner is close to a spherical shape, the contact state between the toner and the toner or the toner and the photoconductor becomes a point contact, so that the adsorbing force between the toners becomes weak and the fluidity increases, and the toner and the photoconductor The attraction force becomes weaker and the transfer rate becomes higher. If either of the shape factors SF-1 and SF-2 exceeds 180, the transfer rate is lowered, which is not preferable.

1 is a schematic diagram illustrating a configuration of an image forming apparatus according to an embodiment of the present invention. It is a schematic sectional drawing which shows the structure of the process cartridge which is one Embodiment of this invention. It is the schematic which shows the structure of a process cartridge frame. It is the schematic which shows the structure of the back face plate used for the process cartridge of this invention. FIG. 2 is a schematic view showing a front side of a photoreceptor arranged in the process cartridge. It is the schematic which shows the structure of the photosensitive layer of a photoreceptor. It is the schematic which shows the structure of the cleaning module used for the process cartridge of this invention, (A) is an external appearance perspective view, (B) is sectional drawing. It is the schematic which shows typically the arrangement | positioning state of the cleaning blade of this invention. It is the schematic which shows the contact conditions of a cleaning blade. It is the schematic which shows a image development module. FIG. 3 is a schematic view showing a face plate for positioning and fixing a developing module to a process cartridge. It is a figure which shows a state when the developing module is positioned by the face plate with respect to the side plate on the frame body front side. It is an assembly drawing of the process cartridge which is one Embodiment of this invention. It is a figure which shows the state which attached the photoconductor to the side plate and attached to the frame body back side. It is a schematic sectional drawing which shows the coating device of a lubricant. It is the schematic which shows the structure of a charging module, (A) is an external appearance perspective view, (B) is an external appearance side view. FIG. 6 is a schematic diagram illustrating a biasing position of a spring material of the charging module before being attached to a process cartridge. It is the schematic which shows the structure of a charging member. It is the schematic which shows the gear train provided inside the side plate. FIG. 6 is a diagram schematically illustrating the shape of a toner in order to explain the shape factor SF-1 and the shape factor SF-2.

Explanation of symbols

10 Image carrier (photoreceptor)
11 Aluminum substrate 12 Photosensitive layer 121 Charge generation layer 122 Charge transport layer 123 Protective layer 13 Front flange 14 Back flange 141 Coupling 15 Shaft 16 Coupling 17 Gear 20 Cleaning module 21 Holding plate 22 Cleaning blade 23 Film 24 Residual toner storage unit 25 Transport auger 26 Case 27 Screw 28 Positioning guide 281 Guide 282 Fixing hole

30 Charging module 31 Charging member (charging roller)
32 Spring material 33 Charge cleaning roller 34 Spacer member 35 Spring support member 36 Bearing 39 Housing 40 Exposure device 50 Development module 51 Development sleeve 511 Rotating shaft 521, 522 Guide 53 Mixing roller 54 Supply roller 55 Restriction member 56 Developer storage unit 561 Partition Plate 60 Transfer device 61 First transfer roller 62 Intermediate transfer belt 62, 63, 64 Rotating roller
65 Tension roller 70 Coating device 71 Film forming member 711 Thinning blade 712 Support member 72 Supply member 721 Film 90 Fixing device 100 Image forming device 110 Reading unit 120 Image forming unit 130 Paper feeding unit 200 Process cartridge 210 Process cartridge frame 211 Reinforcing plate 220 First side plate 221 First contact portion 222 Bearing 225, 226 Fixing hole 230 Side plate 240 Face plate 241 First contact portion 242 Insertion portion 244 Bearing 250 Second side plate 251 Second contact portion 252 Bearing hole hole portion 253 Shaft support portion 254 Fixing hole portion 255 Guide groove 256 Bearing 257 Fixing means 270 Lubricant storage portion

Claims (12)

In a process cartridge that is detachable from an image forming apparatus,
An image carrier;
Cleaning means for removing transfer residual toner on the image carrier;
A holding plate for holding the cleaning means and abutting the cleaning means against the image carrier;
A first side plate provided with a bearing that supports one shaft of the image carrier and a first contact surface that contacts the holding plate;
A process cartridge comprising: a bearing that supports the other shaft of the image carrier; and a second side plate provided with a second contact surface that contacts the holding plate. The process cartridge according to claim 1,
The process cartridge is a cleaning blade. The process cartridge according to claim 2, wherein
The process cartridge, wherein the contact surface contact portion is provided in the vicinity of the width of the bearing. The process cartridge according to any one of claims 1 to 3,
After the holding plate is attached to the first side plate and the second side plate, another process means is attached. Process cartridge. The process cartridge according to any one of claims 1 to 4,
The process cartridge includes application means for applying a powder lubricant. The process cartridge according to claim 5,
The side plate includes a process cartridge frame,
The process cartridge includes a storage portion for storing a powder lubricant in a process cartridge frame. The process cartridge according to claim 5 or 6,
The process cartridge includes an elastomer blade in contact with the image carrier. The process cartridge according to any one of claims 1 to 7,
The process cartridge includes a charging unit that charges the fixed image carrier. An image forming apparatus for visualizing an electrostatic latent image formed on an image carrier with toner, the image forming apparatus including a process cartridge that is detachable from the image forming apparatus.
The image forming apparatus includes: an image carrier; a cleaning unit that removes transfer residual toner on the image carrier; a holding plate that holds the cleaning unit and contacts the cleaning unit with the image carrier; A bearing that supports one shaft of the image carrier, a first side plate provided with a first contact surface that contacts the holding plate, a bearing that supports the other shaft of the image carrier, and An image forming apparatus comprising: a process cartridge including: a second side plate provided with a second contact surface that contacts the holding plate. The image forming apparatus according to claim 9.
An image forming apparatus comprising the process cartridge according to claim 2. 11. The image forming apparatus according to claim 9, wherein the toner used in the developing unit has a volume average particle diameter of 3 to 8 μm and a ratio of the volume average particle diameter (Dv) to the number average particle diameter (Dn) ( Dv / Dn) is in the range of 1.00 to 1.40. 12. The image forming apparatus according to claim 9, wherein the toner used in the developing unit has a shape factor SF-1 in the range of 100 to 180 and a shape factor SF-2 in the range of 100 to 180. An image forming apparatus.

Images