JP2008268470A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent image irregularity caused by contamination on a charging member 102 in an image forming apparatus that includes an image carrier 101 which can rotate and carries a developer, the charging member 102 which can rotate and charges the image carrier, and a transfer means 106 which transfers the developer from the image carrier to a transfer material P. <P>SOLUTION: The image forming apparatus has an inorganic particle supply means 111 for supplying inorganic particles S having perovskite crystals with an average particle diameter D of 0.03 to 0.50 [μm] to the surface of the image carrier 101, a rubbing means 111 for rubbing the surface of the image carrier after the developer is transferred to a transfer material while the inorganic particles are present, and a rotatable cleaning member 103 to be in contact with the charging member to clean the surface of the charging member. The cleaning member is an elastic member having a surface roughness Rzc in an amount 5 to 500 times the average particle diameter D. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention includes a rotatable image carrier that carries a developer, a rotatable charging member that is disposed to face the image carrier and charges the image carrier, and the image carrier to The present invention relates to an image forming apparatus including a transfer unit that transfers a developer to a transfer target.

  A transfer type electrophotographic image forming apparatus, electrostatic recording image forming apparatus, or the like has a rotatable image carrier such as an electrophotographic photosensitive member or an electrostatic recording dielectric. Then, a charging step of charging the surface of the image carrier to a predetermined polarity and potential by a charging unit is provided. There is an electrostatic image forming step of forming an electrostatic image of image information on the charging surface by information writing means. A developing step of developing the electrostatic image with a developer of a developing unit to visualize the electrostatic image; Then, the image forming apparatus includes a transfer step of transferring the image formed by the developer carried on the image carrier to the transfer target. The image carrier is repeatedly used for image formation.

  As charging means for the image carrier, there are non-contact charging means and contact charging means.

  The non-contact charging means is a corona charger such as a scorotron or corotron, and includes a discharge electrode such as a wire electrode and a shield electrode surrounding the discharge electrode, and is disposed in a non-contact manner with the discharge opening facing the image carrier. Is done. Then, by exposing the surface of the image carrier to a discharge current (corona shower) generated by applying a high voltage to the discharge electrode and the shield electrode, the surface of the image carrier is charged to a predetermined polarity and potential.

  The contact charging means is disposed by contacting a conductive member (electrode member) such as a roller type (charging roller), a fur brush type, a magnetic brush type, or a blade type as a charging member on the surface of the image carrier. A predetermined charging bias is applied to the charging member to charge the surface of the image carrier to a predetermined polarity / potential.

  Here, the charging member is not necessarily in contact with the surface of the image carrier. That is, if a dischargeable area determined by the voltage between the gap and the correction Paschen curve is ensured between the charging member and the image carrier, the charging member has a gap of, for example, several tens of μm from the image carrier. They may be arranged close to each other with no gap. Also in this case, the surface of the image carrier is charged (proximity charging). In the present invention, the contact charging means includes this proximity charging.

  The contact charging unit is used in an image forming apparatus such as a laser beam printer because it can be downsized and the amount of ozone generation can be reduced as compared with a corona charger that is a non-contact charging unit.

  In an image forming apparatus having a contact charging unit, a cleaning method in which a pad, a fur brush, or the like abuts or a spiral cleaning member is driven to remove foreign matter such as toner particles attached to the charging unit. Means are provided (Patent Document 1).

  In order to simplify the cleaning means, it has been proposed that the cleaning member is driven by the charging means (Patent Document 2). Moreover, the cleaning member which consists of open-cell melamine resin foam is proposed (patent documents 3-5). Further, cleaning members made of rubber and having hardness and roughness smaller than that of charging means have been proposed (Patent Documents 6 to 7). In addition, a sponge-like cleaning member that defines the number of cells per unit length has been proposed for the accumulation of cleaned foreign matter (Patent Document 8).

On the other hand, in an image forming apparatus, a technique using fine particles having a diameter of several tens to several hundreds of nanometers has been proposed for cleaning performance and prevention of image flow. There is an example in which fine particles having a diameter of 80 to 300 nm, an abrasive and a lubricant are externally added to toner particles (Patent Document 9). In addition, there is an example in which cerium oxide and lubricating particles are used in combination, and inorganic fine particles having a diameter of 20 to 300 nm are used (Patent Document 10). In addition, there is an example in which a toner having particles having a perovskite crystal whose particle shape is defined and having an average primary particle size of 30 to 300 nm is used (Patent Document 11).
Japanese Patent Laid-Open No. 08-137208 JP 05-297690 A JP 2005-257966 A Japanese Patent Laid-Open No. 2005-221981 JP 2000-122505 A Japanese Patent Laid-Open No. 10-063069 Japanese Patent Application Laid-Open No. 08-095350 JP 09-152760 A JP 2004-037734 A JP 2003-140382 A JP 2005-338750 A

  In a system using these fine particles, not only the above-described toner but also fine particles adhere to the charging member. When a large amount or non-uniform adhesion occurs, the charging of the charging member becomes non-uniform, and it is necessary to clean these particles.

  However, the fine particles have a particle size of several tens to several hundreds of nanometers and are generally smaller than the surface roughness of the charging member. Further, since the particle size is small, the adhesion is strong, and it has been difficult for the conventional cleaning means to uniformly clean these fine particles adhering to the charging member. When the cleaning means is driven in order to increase the cleaning efficiency, not only the mechanism such as the drive system becomes complicated, but also the life of one or both may be reduced due to wear of the charging member or the cleaning means.

  An object of the present invention is to provide an image forming apparatus that solves the above-described problems. Specifically, an object of the present invention is to provide an image forming apparatus capable of maintaining cleaning properties that can satisfactorily remove fine particles adhering to a charging member over a long period of time and maintaining stable image characteristics at a high level.

A typical configuration of the image forming apparatus according to the present invention for achieving the above object is as follows:
A rotatable image carrier that carries the developer, a rotatable charging member that is disposed opposite the image carrier and charges the image carrier, and the developer that is covered by the image carrier. In an image forming apparatus having a transfer means for transferring to a transfer body,
Inorganic particle supply means for supplying inorganic particles having perovskite crystals having an average particle diameter D of 0.03 to 0.50 [μm] to the surface of the image carrier;
Rubbing means for rubbing the surface of the image carrier after the developer is transferred to the transfer body in the presence of the inorganic particles;
A rotatable cleaning member that contacts the charging member and cleans the surface of the charging member;
Have
The cleaning member is an elastic member, and the surface roughness Rzc is 5 to 500 times the average particle diameter D.

  According to the present invention, fine particles adhering to the surface of the charging member can be cleaned well with a light load, and good image quality can be maintained over a long period of time.

  By using fine particles having a prescribed particle size and shape, image defects such as image flow can be prevented, the charging means can be prevented from fouling, and the maintenance load can be reduced.

  Hereinafter, one embodiment of the present invention will be described with reference to the drawings. However, the present invention is not limited to the embodiment and experimental examples described below.

<< Schematic Configuration of Image Forming Apparatus Example >>
FIG. 1 shows a schematic configuration of an example of an image forming apparatus according to the present invention. This image forming apparatus is a transfer type electrophotographic image forming apparatus.

  This image forming apparatus has a drum-type electrophotographic photosensitive member 101 as a rotatable image carrier that carries a developer. The image carrier 101 is driven to rotate in the clockwise direction indicated by the arrow X at a predetermined speed.

  The surface of the rotating image carrier 101 is disposed opposite to the image carrier 101 and is uniformly charged to a predetermined polarity and potential by a rotatable charging member 102 that charges the image carrier 101. . In this example, the charging member 102 is a roller-type contact charging member (hereinafter referred to as a charging roller) disposed in contact with the image carrier 101. The charging roller 102 rotates following the rotation of the image carrier 101, and a predetermined charging bias is applied from a power supply unit (not shown).

  A rotating cleaning member (hereinafter referred to as a charging cleaning member) 103 is disposed in contact with the charging roller 102. The charging cleaning member 103 rotates following the rotation of the charging roller 102 to remove foreign matters such as fine particles (roller contaminants) adhering to the surface of the charging roller 102 and clean the charging roller 103.

  Next, image information is exposed to the charged surface of the image carrier 101 by an image exposure unit 104 as information writing unit, and an electrostatic image corresponding to the image information exposed on the surface of the image carrier 101 is formed. Is done. The image exposure unit 104 is, for example, a laser scanning exposure unit. Other digital exposure apparatuses using a combination of a light source such as an LED array or fluorescent light and a liquid crystal shutter may be used. Analog exposure means such as an image imaging projection optical apparatus may be used.

  In a digital image forming method, there are roughly two types of electrostatic image forming methods depending on the relationship between image information and an exposure unit. One is a background exposure method (back exposure method: BAE, Back Area Exposure) in which a non-image portion (background portion) of image information is exposed on the surface of the charged image carrier 101. The other is an image exposure method (IAE: Image Area Exposure) in which an image portion is exposed on the surface of a charged photoreceptor 101. The BAE method employs a regular development method that develops portions other than the exposed background portion. In contrast, the IAE method employs a reversal development method in which a non-exposed portion is developed.

  Subsequently, the electrostatic image is developed as a developer image (toner image) by the developing means 105. The developing unit 105 may be a regular developing unit or a reversal developing unit. In general, development methods of electrostatic images using toner are roughly classified into four types: a one-component non-contact development method, a one-component contact development method, a two-component contact development method, and a two-component non-contact development method. The In the one-component non-contact developing method, non-magnetic toner is applied onto a developer carrying / conveying member such as a sleeve with a blade or the like, or magnetic toner is applied onto the developer carrying / conveying member by a magnetic force. In this method, the electrostatic image is developed in a non-contact state. The one-component contact development method is a method for developing an electrostatic image by applying the nonmagnetic toner or magnetic toner applied on the developer carrying member as described above in contact with the image carrier. The two-component contact development method is a method of developing an electrostatic image by using a two-component developer in which toner and a magnetic carrier are mixed and conveying the magnetic force and applying it in contact with an image carrier. The two-component non-contact developing method is a method for developing an electrostatic image by applying the above two-component developer to the image carrier in a non-contact state.

  The developer includes at least toner particles and an external additive. The toner particles preferably have a mass average particle diameter of 4 to 12 μm from the viewpoints of high image quality and cleanability. Well-known toner particles and external additives can be used. When the circularity of the toner particles is 0.930 or more and 0.970 or less, the toner particles are diffused by the image carrier surface treatment means 107 described later, and a good cleaning property is obtained. Further, with this diffusion, the uniformity in the longitudinal direction in the vicinity of the contact portion of the cleaning means for the inorganic particles S to be described later is also improved, which is preferable.

  The developer image formed on the photoreceptor 101 is transferred to a transfer material (recording material) P as a transfer target (recording medium) in a transfer portion that is a portion facing the transfer means 106. The transfer material P is fed from a feeding unit (not shown) at a predetermined control timing, and is introduced into the transfer portion by the registration unit 113 at a predetermined control timing. In this example, the transfer unit 106 uses a transfer electric roller, which is a contact transfer member, in contact with the photoreceptor 1. A contact nip portion between the image carrier 101 and the transfer roller 106 is a transfer portion. A predetermined transfer bias (transfer bias having a polarity opposite to the charging polarity of the toner) is applied to the transfer electric roller 106 from a power source (not shown) at a predetermined control timing. As a result, the developer image formed on the image carrier 101 is electrostatically transferred to the transfer material P that is nipped and conveyed by the transfer portion.

  The transfer material P that has passed through the transfer portion is separated from the surface of the image carrier 101 and is introduced into a fixing means (not shown) by the conveying means 109. The fixing unit fixes the unfixed developer image on the transfer material P as a fixed image on the surface of the transfer material P by heat, heat and pressure, or pressure. The transfer material P that has undergone image fixing is output as an image formed product.

  The surface of the image carrier 101 after separation of the transfer material is exposed to the entire surface by a discharging unit 108 such as an eraser lamp and subjected to a discharging process. Further, the surface is processed by the image carrier surface processing means 107 and repeatedly used for image formation.

  The image carrier surface processing means 107 has a cleaning member 110 in the container 114 for removing the transfer residual developer from the surface of the image carrier 101 and cleaning the image carrier surface. In addition, inorganic particle supply / sliding means 111 is provided. In this example, the cleaning member 110 is a cleaning blade in which the image carrier 101 is brought into contact with the counter with respect to the rotation direction of the image carrier. The inorganic particle supplying / sliding means 111 is a roller that is brought into contact with the image carrier 101 on the upstream side in the image carrier rotation direction with respect to the cleaning member 110. The roller 111 is rotationally driven in a direction opposite to the rotation direction of the image carrier 101 at a contact portion with the image carrier 101. The roller 111 is brought into contact with the inorganic particle reservoir portion of the tray 115 in which the inorganic particles S are accommodated.

  The inorganic particles S are particles having perovskite crystals having an average particle diameter D of 0.03 to 0.50 [μm] (30 to 500 nm), and are abrasives (cleaning aids) for the image carrier 101. The inorganic particles S of the tray 115 adhere to the surface of the roller 111 and are carried to the contact portion between the roller 111 and the image carrier 101 by the rotation of the roller 111 and supplied to the surface of the image carrier 101. Then, by the rotation of the roller 111, the surface of the image carrier 101 after the transfer is rubbed in a state where the inorganic particles S are present. By supplying and rubbing the inorganic particles S to the surface of the image carrier 101 by the roller 111, the surface of the image carrier 101 is polished and the charged product adhering to the surface of the image carrier is removed.

  In this example, the roller 111 rubs the inorganic particle supply means for supplying the inorganic particles S to the surface of the image carrier 101 and the surface of the image carrier 101 after the transfer in a state where the inorganic particles S are present. It also functions as both the rubbing means.

  Next, the surface of the image carrier 101 rubbed by the roller 111 is wiped off by the contact edge portion of the cleaning blade which is the cleaning member 110. As a result, residual transfer substances (transfer residual toner) adhering to the surface of the image carrier 101, developer external additives such as silica powder, and residual deposits such as inorganic particles S supplied by the rollers 111 are scraped off. Taken and removed. The cleaning blade 110 is an elastic blade made of polyurethane rubber, for example. The scraped remaining deposit is received by the scooping sheet and sent to a waste toner box (not shown) by a toner feed blade, a brush roller, a screw, or the like.

  The configuration of the image forming apparatus is not limited to that shown in FIG. The image forming apparatus of FIG. 2 has a configuration in which the tray 115 containing the inorganic particles S is omitted from the image carrier surface processing means 107 in the image forming apparatus having the configuration of FIG. A roller 112 as a rubbing means for rubbing the surface of the image carrier 101 after the transfer in the presence of the inorganic particles S is brought into contact with the image carrier 101 on the upstream side in the image carrier rotation direction with respect to the cleaning member 110. Arranged. The roller 112 is rotationally driven in a direction opposite to the rotation direction of the image carrier 101 at a contact portion with the image carrier 101.

  The developer contained in the developing means 105 includes, for example, a small particle size external additive having an average particle size of 0.02 μm or less such as silica powder as a lubricant and other auxiliary agents at a predetermined ratio. Has been. Further, inorganic particles S as an abrasive are externally added to the developer in this example at a predetermined ratio.

  The lubricant and inorganic particles S externally added to the developer adhere to the surface of the image carrier together with the toner when developing the electrostatic image on the surface of the image carrier. In the transfer portion, toner mainly moves to the transfer material P, and most of the lubricant and inorganic particles S remain on the surface of the image carrier and are carried to the image carrier surface processing means 107. Then, the inorganic particles S are supplied to a contact portion between the roller 112 and the image carrier 101, and the surface of the image carrier 101 after the transfer is rubbed by the roller 112 in a state where the inorganic particles S are present.

  Further, the inorganic particle supply means for supplying the inorganic particles S to the surface of the image carrier 101 is not limited to the means configuration shown in FIGS. 1 and 2, and may be a supply means having another means configuration.

  The image forming apparatus of FIG. 3 is the same as the image forming apparatus of FIG. 2 except that the charge removing unit 108 is downstream of the image carrier surface processing unit 107 in the rotation direction of the image carrier and the rotation direction of the image carrier from the charging roller 102. The configuration is arranged on the upstream side. The neutralization unit 108 can be disposed at an appropriate position between the transfer unit 106 and the charging unit 102.

  The image forming apparatus shown in FIG. 4 is the same as the image forming apparatus shown in FIG. 2 except that the charging roller 102 is a proximity charging member. That is, the charging roller 102 is arranged so as to face the image carrier 101 in a non-contact manner with a small gap α. The charging roller 102 receives the rotation of the image carrier 101 via a spacer roller abutted on the image carrier 101, and rotates following the rotation of the image carrier 101.

<Image carrier>
As the image carrier 101, a well-known photosensitive member can be used, but one having a low wear rate is preferable. When the wear rate is low, the surface shape of the image carrier is maintained over a long period of time, and there is a variation in durability in a state in which foreign particles such as inorganic particles S and developer external additives pass through the cleaning member 110 of the image carrier surface processing means 107. Since it decreases, it is preferable.

  As an image carrier having a low wear rate, an amorphous silicon-based (referred to as a-Si) photoreceptor, an organic photoreceptor (referred to as OCL-OPC) having a surface protective layer, or the like can be preferably used.

  Further, one of the reasons why the untransferred developer slips through the cleaning member 110 of the image carrier surface processing means 107 is the surface shape of the image carrier (surface roughness of the image carrier).

  Here, in the following description, the surface roughness Rz (Rzc, Rz) and the surface roughness Sm (Smc, Smd) are Rz (10-point average roughness) and Sm (uneven average distance) defined by JISB0601: 1994. ). Rz is an index relating to the height of the unevenness, and Sm is an index indicating the distance of the unevenness. When Rz is large or Sm is small, the image is rough.

  If the Rzd of the image carrier is too large, the piles of slip-throughs such as inorganic particles S and developer become high, and it becomes difficult to clean the charging roller 102 with the cleaning means 103. On the other hand, if the surface roughness Rzd of the image carrier is too small, chattering of the elastic blade portion that is the cleaning member 110 that removes the transfer residual developer from the surface of the image carrier 101 and cleans the surface of the image carrier occurs. It becomes easy. Therefore, a so-called cleaning failure tendency occurs, and the amount of slip-through is increased, which is also not preferable from the viewpoint of cleaning efficiency by the charging cleaning member 103.

  Further, if the Smd of the image carrier is too small, the interval between the peaks due to the slip-through object becomes too narrow, and the cleaning efficiency of the charging cleaning member 103 may be lowered. On the other hand, if Smd is too large, chatter is likely to occur as in the case where Rzd is small, which is not preferable.

  The surface roughness Rzd of the image carrier 101 is preferably 0.1 to 1.0 μm, and Smd is preferably 5 to 30 μm, although it varies depending on the characteristics of the elastic blade that is the cleaning member 110 of the image carrier 101.

  The surface layer of the a-Si photosensitive member is made of a non-single crystal material containing a hydrogen atom, a halogen atom, a hydrogen atom, or a halogen atom with a surface layer of a silicon atom and a carbon atom or a silicon atom or a carbon atom as a base.

  FIG. 10A is a schematic configuration diagram for explaining an example of a layer configuration of an a-Si photosensitive member. In the photoreceptor 101, a photosensitive layer 101b is provided on a support 101a. The photosensitive layer 101b includes a photoconductive layer 101c, a surface layer 101d, and charge injection blocking layers 101e and 101f provided as necessary. Each layer is a well-known a-Si photosensitive material and plasma CVD. It can be created by a known manufacturing method.

  The surface shape of the a-Si photosensitive member can be controlled by forming the photosensitive layer 101b after the surface shape of the supporting member 101a is adjusted by, for example, cutting the supporting member 101a or processing with a rotating ball mill or the like. .

  Specifically, the surface shape of the support can be controlled by adjusting the type, angle, or cutting pitch of the cutting tool when cutting the support 101a such as an aluminum cylinder. Further, the manufactured a-Si photosensitive member has a surface shape corresponding to the surface shape of the support 101a as shown in FIG. 10B. Furthermore, it is possible to control the surface shape by polishing the surface of the prepared photoreceptor using a polishing tape or the like. Further, it depends on the flow rate of the raw material gas at the time of forming the a-Si photosensitive layer, the film discharge conditions such as the plasma discharge power and the substrate temperature. For example, in the case of manufacturing by plasma CVD, when the source gas flow rate is increased and the discharge power / source gas flow rate ratio is increased, Rz and Ra tend to increase. These methods for controlling the surface shape may be controlled independently or in combination.

<< Charging member 102 >>
As charging means, roller charging means using a charging roller is preferably used. The roller charging unit is provided with a charging roller 102 as a charging member in contact with or close to the image carrier 101. In the case of contact arrangement, the contact charging method is used, and in the case of proximity arrangement, the proximity charging method is used. The charging roller 102 is rotated by the rotation of the image carrier 101 in both the contact charging method and the proximity charging method. It may be positively driven to rotate. A DC bias having a polarity corresponding to the image carrier is applied to the charging roller 102 by a power supply unit (not shown). Further, an AC bias may be superimposed (referred to as AC / DC).

  In the contact charging method, the charging roller 102 is brought into contact with the image carrier 101 with a predetermined pressure, and the image carrier is charged by electric discharge in the contact nip portion and the region near the contact nip. In order to prevent foreign matter on the image carrier from being pressed against the charging roller and firmly attached thereto, the pressure at which the charging roller 102 contacts the image carrier 101 is preferably 30 g / cm or less.

  On the other hand, in the proximity charging method (FIG. 4), the gap interval α between the image carrier 101 and the charging roller 102 is 500 μm or less, preferably 20 to 300 μm, more preferably 100 μm or less at the closest part. Therefore, it is distinguished from corona charging, in which the distance from the image carrier is as large as several millimeters. In the proximity charging method, charging is performed with a bias substantially equal to that of the contact charging method. If the gap α is too large, charging is likely to be unstable. If the gap α is too small, the surface of the charging roller is contaminated when there are abrasive particles remaining on the image carrier. It becomes easy.

  A known member can be used for the charging roller 102, but the surface thereof is preferably highly releasable. In particular, a surface layer obtained by crosslinking and curing polysiloxane containing fluorine atoms with ultraviolet rays or the like has high releasability. Furthermore, since it has a hybrid structure of organic-glass body and is soft unlike so-called normal glass, it can be suitably used as the surface of a charging roller.

  If the surface layer is too thin, so-called bleed out may occur in which the internal material of the charging roller oozes out after long-term use. In addition, the surface shape of the charging roller may be deformed by a local pressing of the cleaning unit 103, or a foreign matter attached to the charging roller may be embedded. Scratches may occur. On the other hand, if it is too thick, the adhesion between the surface layer and the base layer may decrease, the resistance as a charging roller may increase, and the surface layer thickness may be uneven. Therefore, the thickness of the surface layer is preferably 0.1 μm to 1.0 μm.

  In the case of the proximity charging method, a member such as a spacer roller is provided at the end of the charging roller 102 so that the gap α between the charging roller (electrode) 102 as the charging member and the image carrier 101 can be maintained at a predetermined level. You can also do things.

  Although a well-known thing can be used for the material of the proximity charging member, it is generally set to a higher hardness than the contact charging means. Any hardness that can maintain the gap α is acceptable.

  The proximity charging method is good against dirt due to the fact that the charging roller 102 which is a proximity charging member is not in contact with the image carrier 101, and that foreign matter is difficult to press and rub against the charging roller 102. It is a tendency. However, the developer that has passed through the cleaning member 110 of the image carrier 101, in particular, an external additive or the like electrostatically adheres to the charging roller 102 and the roller surface is contaminated.

  Contaminants once adhering to the charging roller 102, in particular, fine particles represented by the above-mentioned inorganic particles S having an average particle diameter D of about 0.03 to 0.50 [μm] have electrostatic adhesion force. Than the non-electrostatic adhesion force such as van der Waals force. Therefore, it is difficult to remove by bias as compared with toner particles having a large particle size of several μm. For the removal of such fine particles, a contact-type cleaning means can be preferably used.

<Charging cleaning member 103>
As described above, the contact cleaning type is preferable as the charging cleaning member 103 for cleaning the charging roller 102.

  As the charging cleaning member 103, a known member such as a fur brush, an elastic member, or a magnetic brush can be used. By providing a rubbing / recovering process separately from the cleaning blade 110, it is possible to reduce the rubbing and polishing load on the surface of the image carrier on the cleaning blade 110, and it is effective in suppressing the wear of the cleaning blade 110.

  A method in which the charging cleaning member 103 is brought into contact with the charging roller 102 and is rotated along with the charging roller 102 is preferable from the viewpoint of simplification of the apparatus configuration and reduction in size and cost.

1) Elastic Cleaning Member As the charging cleaning member 103, a cleaning member made of an elastic member can be used. The hardness Z of the charging cleaning member 103 is preferably 10-60 degrees in terms of Asker C hardness. The surface roughness Rzc of the electrostatic cleaning member 103 is preferably 5 to 500 times the particle size D of the inorganic particles S. The hardness Z is preferably 10 ≦ Z × Rzc ≦ 500 with respect to the particle size D of the inorganic particles S. Furthermore, the Smc of the charging cleaning member 103 is preferably 1E2 to 1E4 times (1 × 10 ² to 1 × 10 ⁴ times) the particle size D.

  In these ranges, the inorganic particles S are scraped off from the charging roller 102, and are suitably blown off without being excessively accumulated in the charging cleaning member itself.

2) Foam cleaning member As the charging cleaning member 103, a cleaning member made of a foam member can be used. It is preferable that the hole density on the surface of the charging cleaning member 103 is 40 to 80%. If the pore density is too low, inorganic particles S may be excessively accumulated on the cleaning member 103 and the cleaning ability may be reduced. In addition, the resin part rubs the inorganic particles S against the charging roller 102 to be strong. May adhere.

  On the other hand, if the pore density is too high, the resin portion becomes brittle, and the ability to scrape the fine particles may decrease, mechanical durability may decrease, and scraping unevenness may occur. The pore diameter Dc is preferably 1E2 to 1E4 times the particle diameter D of the inorganic particles S.

  In these ranges, the inorganic particles S are scraped off from the charging roller 102 to suppress excessive accumulation on the charging cleaning member itself, and it is suitable for flipping off.

  The hole diameter Dc and the hole density are obtained by observing the surface of the cleaning member 103 with a microscope and observing 500 or more holes at random in a plurality of locations in the circumferential direction and the longitudinal direction of the charging cleaning member. It was. Although FIG. 8 shows a case where the holes are circular when observed, the hole diameter Dc is measured for each hole, and the hole density is obtained from the Dc and the number of holes per unit area. It was. Further, when the shape was not circular, the hole density was determined from the average equivalent circle diameter of the same area and the number of the holes.

3) Surface shape of charge cleaning member 103 and surface shape of image carrier 101 FIG. 13 is a schematic diagram of the surface shape of image carrier 101, the slip-through substance adhering to charging roller 102, and the surface shape of charge cleaning member 103. Indicates. For simplification, the surfaces of both the image carrier 101 and the charging cleaning member 103 are schematically shown as jagged, and the intervals between the jagged edges become Smd and Smc, respectively.

  According to the surface shape Rzd and Smd of the image carrier 101, slipping-out substances such as external additives are used. It adheres to the charging roller 102 as shown by a filled triangle in the figure (lower part of 102 in the figure).

  The attached slip-through substance moves to a portion facing the charging cleaning member 103 as the charging roller 102 rotates (upper portion 102 in the figure).

  It is also preferable to set the ratio of Smc to Smd (Smc / Smd) so that it is not an integer. When Smc / Smd is 1, that is, at the same interval, the gap between the slip-through substance and the charging cleaning member 103 matches as shown on the left side in the drawing, and the cleaning efficiency may be reduced. Further, when Smc / Smd is 2, there may be a portion that is satisfactorily cleaned, such as a dashed white mountain as shown on the right side of the drawing, and a portion of a filled mountain that is not sufficiently cleaned. When the difference in cleaning efficiency is large, the charging uniformity of the charging roller 102 at the corresponding portion is lowered, and a streak-like image defect may occur. For this reason, it is preferable that Smc / Smd is not an integer.

4) The outer diameter ratio between the charging cleaning member 103 and the charging roller 102 The outer diameter ratio between the charging roller 102 and the charging cleaning member 103, that is, [the average outer diameter of the charging roller] / [the average outer diameter of the charging cleaning member] is Set not to be an integer. Thereby, even if there is an insufficiently cleaned point, it can be prevented from accumulating in the circumferential direction of the charging roller 102 and growing into ring-shaped dirt.

5) Measurement of surface shape The surface shapes Rzc and Smc of the charging cleaning member 103 and the surface shapes Rzd and Smd of the image carrier 101 are Rz and Sm defined in JIS B0601: 1994. The measurement is performed using a surface roughness measuring instrument (Surfcoder SE-3400: manufactured by Kosaka Laboratories), with a measurement length of 8 mm, a speed of 0.05 mm / sec, a cutoff λc of 0.8 mm, and a JIS 1982 mode. The measurement was performed in the longitudinal direction of the image carrier 101.

  For both the charging cleaning member 103 and the image carrier 101, measurements were made for a total of 40 points, 8 points in the circumferential direction and 5 points in the longitudinal direction, and the average value was used as the value of each surface shape.

6) Manufacture of the charging cleaning member 103 The charging cleaning member 103 can be manufactured, for example, by bonding the cored bar 103-S and the charging cleaning member 103 as shown in FIG. The electrified cleaning member 103 is preferably bonded to the core metal 103-S after being heated and / or compressed in at least the longitudinal direction.

  After compressing the bulk of the original material, a hole for inserting the cored bar 103-S is created, the cored bar 103-S is inserted and bonded, and then the bulk outer shape is formed by cutting or the like. In addition, after the bulk is passed through the core metal 103-S, the compression may be performed to complete the bonding. In this case, a countermeasure such as using a slow-drying adhesive may be used.

  By subjecting the compression process to the longitudinal direction, resistance to twisting and pulling in the longitudinal direction is improved, and durability can be improved without greatly increasing the overall hardness.

  Further, it has been found that particularly when the charging cleaning member 103 is made of a foam member, it is effective to achieve both improvement in cleaning efficiency and high durability, as will be described later.

  Generally, the foam is formed of a space (cell) 2a-1 and a wall (solid) 2a-2 as shown in the schematic diagram of FIG. Therefore, factors affecting the hardness of the foam include the volume ratio of the space (cell) 2a-1 in the unit volume and the hardness of the wall (solid) 2a-2. Therefore, when viewed from the viewpoint of the hardness of the foam, the foam can be made to have a lower hardness as the volume ratio of the space 2a-1 is larger and the wall 2a-2 is lower in hardness.

  To increase the volume ratio of the space 2a-1 in the unit volume, increase the cell diameter and increase the space 2a-1, or increase the cell diameter, or increase the space 2a-1. do it. However, the solid portion 2a-2 having elastic force is reduced, and the durability is lowered, for example, permanent deformation occurs due to a decrease in deformation recovery force. Due to these problems, there is a limit to the increase in cell diameter.

  On the other hand, in order to reduce the hardness of the wall 2a-2, it is necessary to add a large amount of a material having a plasticizing effect, such as a plasticizer and a softening agent. This results in a decrease in durability. It is practically difficult to greatly reduce the hardness when the addition amount is within a range where these phenomena do not occur.

  In view of such a situation, as a result of analyzing conventional foams, it has been found that these phenomena are caused by the cell shape being a perfect circle or close to it. Consider it with reference to FIG.

  That is, if the cross-sectional shape of the cell 2a-1 is a shape close to a perfect circle like a conventional foam, the wall 2a having a thickness distribution in a shape that theoretically follows the shape of the circle even if the cell diameter is increased. -2 is made. Therefore, a thick (L1) place and a thin (L2) place coexist in the wall 2a-2, and it is difficult to make the wall 2a-2 thin uniformly. If the hardness is measured in this state, the influence of the thick part of the wall 2a-2 appears dominantly, so the hardness is not lowered as expected. Further, when stress is applied to the foam, the stress concentrates on the thin portion (L2) of the wall 2a-2, so that a phenomenon that deformation concentrates on the thin portion (L2) is likely to occur.

  In order to dramatically improve such essential problems, it is effective to make the cell shape irregular. By making the cell shape irregular, the wall 2a-2 can have a fairly uniform thickness. When the hardness of the foam is measured, there is no influence of the thick part (L1) of the wall 2a-2, so that the hardness can be reduced. Further, when a load is applied to this foam, there is no influence of the thin part (L2) of the wall 2a-2, so that stress is moderately dispersed throughout the wall without concentrating on a part, and deformation is also applied to the entire wall. Occurs in an averaged form. Thereby, it is possible to reduce both an increase in local deformation and an increase in local stress.

  The charging cleaning member 103 needs to have flexibility such as followability to the charging member surface or scraping property while suppressing permanent deformation and improving durability. Therefore, it is preferable that the cell 2a-1 is non-circular in the longitudinal cross section of the charging cleaning member 103, and circular in the rotational direction (circumferential direction) cross section.

  Moreover, it is preferable that the cell diameter in an arbitrary cross section has a certain distribution. This is because when the cell diameter distribution is appropriate, the cells 2a-1 are likely to be close-packed, and as a result, the cell wall thickness and variations thereof are reduced, and the effects of the present invention are more easily obtained. In addition to this, it is also effective for cleaning defects due to large-diameter holes due to foaming non-uniformity or the like.

  When such a cell 2a-1 is observed from the surface, it becomes a non-circular shape such as an ellipse as shown in FIG. Although it depends on the physical properties of the resin used, the ratio of minor axis La / major axis Lb (minor axis / major axis ratio) is preferably 0.6 to 0.9.

  When the La / Lb ratio exceeds 0.9, the effect of compression cannot be obtained. On the other hand, when it becomes a very long and narrow shape of less than 0.6, when the charging cleaning member 103 comes into contact with the charging roller 102, the cell 2a-1 is blocked or inorganic particles or the like are easily packed in the cell 2a-1. For example, the function as a foam may deteriorate.

  In the compression step, for example, a bulk base material may be put into a cylindrical container 1501 as shown in FIG. 15 and compressed using pressure members 1502 and 1503. At that time, the container 1501 and the pressure members 1502 and 1503 may be heated.

  Thereby, the electrification cleaning member 103 becomes a thing produced through the compression process at least in the longitudinal direction. In the case of the charging cleaning member 103 made of a foam member, the shape of the cell 2a-1 is a product created through a compression process in the longitudinal direction.

<< Inorganic particle S >>
As the inorganic particles which are abrasives for removing the charged product adhering to the surface of the image carrier, inorganic particles having perovskite crystals having an average particle diameter D of 0.03 to 0.50 [μm] are preferable. .

  Examples of the material having a perovskite crystal structure include strontium titanate and calcium titanate. The abrasive particles preferably have an average particle size of 0.03 to 0.50 [μm]. More preferably, it is 0.10 to 0.30 [μm] (100 nm to 300 nm). In this range, sufficient polishing action and further action as a lubricant at the cleaning blade nip portion can effectively prevent image flow and maintain good cleaning performance, and can be used for cleaning blades and image carriers. It is possible to suppress wear and obtain a good image for a long time.

  In the case of a small particle size of 0.03 [μm] (30 nm) or less, the polishing action is reduced. In particular, when a cleaning blade is used as the rubbing member 110, the amount of slipping through the cleaning blade is large. For example, the irradiation of the image carrier 101 may be hindered. In addition, the cohesiveness is increased, the fluidity, that is, the uniform supply to the cleaning blade is lowered, or the secondary particle has a large particle size, and the cleaning blade or the image carrier may be worn. On the other hand, in the case of a large particle size exceeding 0.50 [μm] (500 nm), it becomes difficult to enter the vicinity of the nip between the cleaning blade and the image carrier, particularly the wedge-shaped portion, and further the cleaning blade nip portion. For this reason, the rubbing may be insufficient or the cleaning blade or the image carrier may be worn.

  When the content of aggregates having a particle size of 0.60 [μm] (600 nm) or more is 1% by number or less, good results can be obtained. In the case where particles and aggregates of 0.60 [μm] or more are contained in excess of 1% by number, the electrostatic latent image bearing member even if the primary particle size is less than 0.50 [μm]. In some cases, scratches may occur. However, the combination of BAE and a-Si, or the cleaning is disposed above the image carrier, and the aggregate is easily loosened in the cleaning process, thereby suppressing the number to 1% or less. This makes it easy to do things.

  About the average particle diameter of the inorganic particle S, 100 particle diameters were measured from the photograph image | photographed by the magnification of 50,000 with the electron microscope, and the average was calculated | required. The particle size was determined as (a + b) / 2, where a is the longest side of the primary particles and b is the shortest side.

  Furthermore, when the inorganic particles S are added to the developer (FIGS. 2, 3, and 4), the liberation rate with respect to the toner particles is preferably 20% by volume or less, and more preferably 15% by volume or less.

  Here, the liberation rate is obtained by determining the ratio of perovskite-type crystalline inorganic particles liberated from the toner particles in volume%. That is, a known principle ("Japan Hardcopy 97 Proceedings" pages 65-68 (publisher: Electrophotographic Society, issue date: July 9, 1997)) by a particle analyzer (PT1000: manufactured by Yokogawa Electric Corporation) It was measured by.

  The shape of the inorganic particles S may be indefinite, but if the circularity is 0.930 or less, it is suitable for removing charged organisms.

  It is more preferable that the shape has a ridge line or a corner, for example, a rectangular parallelepiped shape as shown in FIGS. It is preferable that the content of the rectangular parallelepiped particles is 50% by number or more because the charged product can be more efficiently removed.

  FIG. 11 is an electron micrograph (SEM photograph) of an example of a rectangular parallelepiped inorganic particle S. FIG. 12 is a conceptual diagram of a rectangular parallelepiped shape. L1 to L4 are ridge lines or corners.

  The inorganic particles S of perovskite crystals can be produced by a known sintering / pulverization method. In addition, the rectangular inorganic particles S, for example, by adding a strontium hydroxide to a titania sol dispersion obtained by adjusting the pH of a hydrous titanium oxide slurry obtained by hydrolyzing a titanyl sulfate aqueous solution, It can synthesize | combine by heating to reaction temperature. By setting the pH of the hydrous titanium oxide slurry to 0.5 to 1.0, a titania sol having good crystallinity and particle size can be obtained.

  For the purpose of removing ions adsorbed on the titania sol particles, it is preferable to add an alkaline substance such as sodium hydroxide to the titania sol dispersion. At this time, it is preferable that the pH of the slurry is not 7 or higher so that sodium ions and the like are not adsorbed on the surface of the hydrous titanium oxide. The reaction temperature is preferably 60 ° C. to 100 ° C., and in order to obtain a desired particle size distribution, the temperature rising rate is preferably 30 ° C./hour or less, and the reaction time is preferably 3 to 7 hours.

As a method for subjecting the inorganic particles S produced by the above method to surface treatment with a fatty acid or a metal salt thereof, there are the following methods. For example, in an Ar gas or N ₂ gas atmosphere, the inorganic particle slurry can be placed in a fatty acid sodium aqueous solution to precipitate the fatty acid on the perovskite crystal surface. In addition, for example, in an Ar gas or N ₂ gas atmosphere, the inorganic fine particle slurry is placed in a fatty acid sodium aqueous solution, and the desired metal salt aqueous solution is dropped while stirring to precipitate and adsorb the fatty acid metal salt on the perovskite crystal surface. Can be made. For example, if a sodium stearate aqueous solution and aluminum sulfate are used, aluminum stearate can be adsorbed.

"Example"
<Inorganic particle production example>
In the following production example, inorganic particles S, that is, abrasive particles made of strontium titanate were prepared.

The hydrous titanium oxide obtained by hydrolysis by adding aqueous ammonia to the aqueous titanium tetrachloride was washed with pure water, and 0.3% sulfuric acid was added to the hydrous titanium oxide slurry as SO _{3 with} respect to the hydrous titanium oxide. Added.

  Next, hydrochloric acid was added to the hydrous titanium oxide slurry to adjust the pH to 0.6 to obtain a titania sol dispersion. NaOH was added to the titania sol dispersion to adjust the pH of the dispersion to 5.0, and washing was repeated until the electrical conductivity of the supernatant liquid reached 50 μS / cm.

0.97-fold molar amount of Sr (OH) ₂ .8H ₂ O was added to the hydrous titanium oxide, and the mixture was placed in a SUS reaction vessel and purged with nitrogen gas. Furthermore, distilled water was added so as to be 0.6 mol / liter in terms of SrTiO ₃ . The slurry was heated to 60 ° C. at a rate of 10 ° C./hour in a nitrogen atmosphere, and reacted for 7 hours after reaching 60 ° C. After the reaction, the reaction solution was cooled to room temperature, and the supernatant was removed. Then, the washing was repeated with pure water, and then filtered with Nutsche. The obtained cake was dried to obtain strontium titanate fine particles not passing through the sintering step. The strontium titanate fine particles were designated as inorganic particles A.

Further, the production conditions such as the amount of Sr (OH) ₂ · 8H ₂ O, pH, slurry temperature rising conditions were varied to prepare inorganic fine particles B to M and comparative fine particles A to E having different particle sizes and shapes. .
Table 1 shows the physical properties of these fine particles.

<Example of image carrier production>
The surface of the support 101a (FIGS. 10A and 10B) having an outer diameter of 30 mm (described as φ30) was cut using a commercially available cutting lathe.

  In this example, a flat cutting tool is used, a film is formed by a well-known RF-CVD method on a support 101a that has been cut by adjusting the setting angle and pitch of the cutting tool, and the image carrier P01 is a A -Si photoconductor was obtained.

  In general, in an a-Si photoconductor produced by a CVD method such as RF-CVD, the shape of the support 101a generally affects the surface shape of the photoconductor produced as shown in FIG. 10B. That is, the surface shape of the photoconductor can be controlled by controlling the shape of the support 101a.

  Table 2 shows the surface roughnesses Rzd and Smd of the created image carrier P01.

Note) Definition of surface roughness conforms to JISB0601: 1994. Although details are omitted in this example, the surface shape can be controlled by changing the conditions of plasma CVD. For example, when substrates having the same shape are used, Rz increases when the raw material gas flow rate is increased and the discharge power / gas flow rate is increased. In addition, the surface shape can be controlled by adjusting various manufacturing conditions such as control of the substrate temperature.

<Developer production example>
In the following production example, a developer composed of toner particles and various additives was prepared.

Well-known polyester binder resin 100 parts by weight Magnetic iron oxide 100 parts by weight Monoazo iron compound 2 parts by weight Salicylic acid Al compound 1 part by weight Fischer-Tropsch wax 4 parts by weight (DSC peak top temperature = 104 ° C., Mw / Mn = 1.8 )
The mixture was premixed with a Henschel mixer.

  This was melt kneaded with a biaxial extruder heated to 130 ° C., and the cooled kneaded product was coarsely pulverized with a hammer mill to obtain a coarsely pulverized toner product.

  The obtained coarsely pulverized product is adjusted to -15 ° C at the inlet air temperature, 48 ° C at the outlet air temperature, and -5 ° C to cool the cooling rotor and liner, using a mechanical pulverizer turbo mill. And then pulverized by mechanical pulverization.

  The obtained finely pulverized product was subjected to strict classification and removal of fine powder and coarse powder at the same time using a multi-division classifier (elbow jet classifier manufactured by Nittetsu Mining Co., Ltd.) using the Coanda effect.

  Thereafter, toner particles having various degrees of circularity were prepared using a mechanical surface reformer.

To 100 parts by mass of the toner particles, 1.5 parts by mass of hydrophobized silica particles obtained by subjecting dry silica of BET 200 m ² / g to hydrophobization was mixed with a Henschel mixer. Thus, negatively chargeable toners T1 to T9 having a weight average particle diameter X of 6.4 μm and an average circularity a (T) as shown in Table 3 were obtained.

<Evaluation equipment>
As an evaluation apparatus, a Canon copier iR400 was modified to obtain an evaluation machine as shown in FIG. Specifically, an LED having a peak wavelength of 680 nm was used as the static elimination means 108, and was disposed between the transfer process and the cleaning process as shown in FIG.

  The surface speed of the image carrier 101 is 250 mm / sec, and the bias conditions applied to the charging, developing, and transfer means can be changed for regular development of the positively charged a-Si photosensitive member and the negatively charged developer. did. The latent image exposure means 104 was modified to a BAE having a wavelength of 660 nm, a spot diameter of 40 μm, and 600 dpi.

As the charging roller 102 and the charging cleaning member 103 as charging means, iR400 products were used as they were. The charging roller 102 is a roller having an average outer diameter φ16.
Further, the waste toner feed blade of the iR400 cartridge was removed, the inorganic particles S were set in the cartridge, and a fur brush was installed as a member 111 for supplying the inorganic particles S to the image carrier. In FIG. 1, the shaded area is the inorganic particle installation area. The supply member 111 is 70% (−70% of the surface speed of the image carrier) in the counter direction with respect to the surface movement direction of the image carrier 101 at the contact portion with the surface of the image carrier. It was made to rotate at a speed of (noted).

<Experimental example>
Using the image carrier P01 in Table 2 and the developers T1 to T9 in Table 3, the inorganic fine particles A to M and the comparative fine particles A to E in Table 1 were evaluated.

  Using the evaluation apparatus described above, ruled lines (500 μm lines at equal intervals in the sheet passing direction as shown in FIG. 9 were arranged at 10 mm intervals in a (H / H) environment of 30 ° C./80% humidity. An image ratio of 5%) was used as a manuscript and was continuously fed at 20k sheets / day, and various evaluation images were formed. The main switch was turned off and left at night. The next morning, after the evaluation image was formed, the 20 k sheet / day printing durability test was continued in the same manner, and the printing durability test up to 300 k was performed.

  Next, in a (L / L) environment at a temperature of 10 ° C./humidity of 15%, similarly, 100 k sheets, a total of 400 k sheets, was passed.

  In addition, as an image for evaluation, a grid image in which 300 μm lines were crossed at intervals of 5 mm, a halftone image of 1 dot 1 space, 1 dot 2 space, solid black, and a 17 gradation image were formed.

  For “image flow”, the evaluation image was visually evaluated in an H / H environment.

  For “cleaning durability (CLN durability)”, the edge portion of the cleaning member was observed with a microscope before and after the durability, and the wear level was evaluated.

  “Image carrier durability” was evaluated based on the amount of abrasion and scratches on the surface of the image carrier. The amount of wear was measured with a reflection spectroscopic interferometer (trade name: MCPD-2000, manufactured by Otsuka Electronics Co., Ltd.), and was calculated as wear rate [nm / rotation] per rotation. Further, the scratch on the surface of the image carrier was determined by visual observation of the surface of the image carrier and the presence or absence of scratches or streaks on the image.

  The evaluation criteria are as follows.

1) “Image flow” (H / H environment)
Judgment was made from the sample image of the morning after printing. The judgment criteria are as follows.

◎: Very good ・ ・ No blurring of lines and dots in the above evaluation image ○; Good ・ ・ Lattice image cannot be recognized and dot blurring or density drop in some areas of halftone or gradation image Yes. However, it can be recovered within 50 sheets of A4 paper. ●: Practical use ・ Lattice image cannot be recognized and dot blurring or density decrease in halftone or gradation image. 50 to 100 sheets until recovery Δ: Practical use ・ Lattice image cannot be recognized and dot blurring or density decrease in halftone or gradation image. Over 100 sheets until recovery. Or, it is possible to recognize a little flow with the grid image, but within 50 images until the flow recovery of the grid image ×: Other than the above ・ ・ Flow recognition is performed with the grid image 2) “CLN durability”
After the printing durability test, the cut surface and the contact surface of the cleaning blade were observed with a microscope, and cleaning defects such as chipping and scuffing of the cleaning blade, toner slipping, chattering and scoring were evaluated. The judgment criteria are as follows.

A: Very good ・ No blade chipping. No more than 3 spots or chippings below the toner particle size. No slip-through. No turn-over, chatter, or resonance sound. ○: Good. No wrinkles or chipping beyond the toner particle size. No slip-through. No turning, resonance may occur when the image carrier is stopped, or chatter may occur (frequently)
●: Practical use ・ 6-10 spots of wrinkles or chips below the toner particle size. There are wrinkles or chips larger than the toner particle size, but none more than twice the toner particle size. No slip-through. Resonance or chatter may occur (rare)
△: Practical use ・ Trenches or chips below the toner particle size are 10 or more. There are wrinkles or chippings twice or more than the toner particle size, but there is no slipping. Both resonance and chatter may occur (rare)
X: Other than the above--there may be slipping out due to blade wear such as chipping / skinning or mekre. 3) “Image carrier durability”
Film thickness wear of the image carrier before and after the printing durability test was measured. In the measurement of the film thickness of the image carrier, the surface layer thickness of the image carrier was measured at a total of 36 locations, 6 in the circumferential direction and 6 in the long axis direction, and the average value was defined as the average surface layer thickness. The amount of wear was calculated by dividing the difference in the average surface layer thickness before and after the endurance and the number of rotations of the image bearing member as wear rate per 10,000 rotations [nm / 10k rotation (rot)]. The image density was measured as an absolute density, and the above image at the time of each image evaluation was measured using a densitometer “RD-918” (manufactured by Macbeth). The judgment criteria are as follows.

◎: Very good ・ ・ Wear Rate is 1.5 [nm / 10 krot] or less and no uneven wear ○; Good ・ ・ Wear Rate is 1.5 [nm / 10 krot] or less, and there is uneven wear, but 2.0 No measurement points exceeding [nm / 10 krot]. In addition, the difference in image density between the unevenly worn portion and the vicinity thereof is 0.2 or less. X; Other than the above. · There are measurement points where the wear rate exceeds 1.5 [nm / 10 krot] or exceeds 2.0 [nm / 10 krot]. . Alternatively, the difference in image density between the unevenly worn portion and its vicinity exceeded 0.2. All the toners T1 to T9 obtained almost the same results.

  Table 4 shows the evaluation results when using toner T4 (circularity 0.941).

  From Table 4, when the average primary particle diameter D of the inorganic fine particles is 0.03 to 0.50, and more preferably 0.10 to 0.30 [μm], the image flow, the cleaning durability, and the wear of the image carrier are deteriorated. It turns out that it is suitable. Further, a better result was obtained when the circularity was 0.930 or less.

  Further, the method of supplying the inorganic particles S is not limited to this, and for example, the inorganic particles S can be supplied from the developing means. As a developer to be used, 1.5 parts by mass of hydrophobic silica particles are mixed with a Henschel mixer with respect to 100 parts by mass of toner particles prepared in the developer production example. At that time, 1.0 part by mass of inorganic particles was further added. Except for this, toner T10 prepared in the same manner as toner T4 was used.

  On the other hand, the evaluation apparatus removed the tray 115 (FIG. 1) containing the inorganic particles S and the inorganic particle supply member 111 and performed the same evaluation as the original waste toner feed blade. Similar results were obtained.

  Instead of the feed blade, a rotatable rubbing member 112 for rubbing the surface of the image carrier through the inorganic particles S may be provided. As the rubbing member 112, a known member such as an elastic member or a fur brush can be used. Further, if the developer is a magnetic toner, a magnetic material may be used.

  Thereafter, in the examples, unless otherwise specified, toner T10 and fine particles A to M obtained with the above-described good results are used. Further, as the evaluation apparatus, an apparatus provided with the rubbing member 112 as shown in FIG. 2 is used. The rubbing member 112 was a roller made of urethane foam with Asker C hardness of 30 degrees and was driven at a speed of + 40%.

<Method for holding electrified cleaning member>
As shown in FIG. 7, a guide slot is added so that the core metal part 103 -S of the roller-shaped charging cleaning member 103 can move up and down, and further, it contacts the charging roller 102 with a predetermined pressure. A pressurizing means (pressurizing spring) S103 is provided. H103 is a charging cleaning member holder and is movable along the guide slot.

  Further, a driving mechanism (not shown) that rotates the charging cleaning member 103 in synchronization with the driving of the image carrier 101 is provided.

  The contact pressure of the charging cleaning member 103 to the charging roller 102 is performed using the pressurizing unit S103. In order to set the contact pressure below the dead weight of the charging cleaning member 103, the pressurizing means S103 may be attached in the reverse direction (the lower side in FIG. 7).

  The charging roller 102 is also provided with a guide slot so that the mandrel can be moved up and down, and further provided with a pressurizing means (pressurizing spring) S102 so as to come into contact with the image carrier 101 with a predetermined pressure. . H102 is a charging roller holder and is movable along the guide slot.

[Example 1]
<Production Examples DR1 to DR5 of the electrification cleaning member>
As the electrostatic cleaning member 103, an elastic roller made of urethane rubber in which carbons having different particle diameters are dispersed on a core metal having an outer diameter of 7 mm (φ7) and a length of 350 mm was prepared by a known method.

  The elastic roller is formed on a cored bar, and then is cut and polished to form a cylindrical shape having an outer diameter of 12 mm (φ12) and an effective length of 310 mm, and the charging cleaning members DR1 to DR5. Got.

  Thereafter, unless otherwise specified, the cores are made to have the same dimensions as the above-described charging cleaning members DR1 to DR5.

  The surface shapes of the electrostatic cleaning members DR1 to DR5 were controlled by adjusting the particle size of the dispersed carbon black, adjusting the grindstone in the cutting / polishing process, and the like.

  The prepared charging cleaning members DR1 to DR5 were set to have Asker-C hardness (Z) of 20 ± 3 degrees. The surface of each elastic roller DR1-DR5 was irregular uneven | corrugated like the schematic diagram of FIG. Table 5 shows Rzc and Smc of the charging cleaning members DR1 to DR5.

  Table 6 shows the ratio of Rzc of the electrostatic cleaning member DR to the average particle diameter D of the fine particles, and Table 7 shows the ratio of Smc to D.

  These charging cleaning members DR1 to DR5 are brought into contact with the charging means at a linear pressure of 3 g / cm, and a relative speed of 110% in the forward direction with respect to the charging roller 102 at the contact portion with the charging roller 102 ( + 110%).

  Using inorganic fine particles A to M, a printing durability test of 100 k sheets was performed in an H / H environment and an L / L environment. The charging uniformity was evaluated in both environments. Specifically, charging uniformity was evaluated from a normal halftone image and a solid image and a halftone image prepared by adjusting the bias condition of the developing unit in a state where the latent image exposure was not performed. As a comparative control, printing durability and evaluation were similarly performed without a cleaning member.

  When the charging roller 102 comes into contact with the image carrier 101, the contamination of the charging roller 102 is more in the H / H environment, whereas the influence of the contamination of the charging roller 102 on the charging uniformity is in the L / L environment. Was remarkable.

  Therefore, the evaluation was made based on the result of evaluating the charging uniformity of the charging roller that was printed in an H / H environment.

◎; Charge uniformity good ○; Good ●; Normal image is not affected by contamination △; Normal image problem does not occur in printing durability environment ×: Charge nonuniformity due to contamination occurs in normal image Table 8 shows the results .

  When Rz on the surface of the charging cleaning member 103 is 5 to 500 times the average particle diameter D, the charging cleaning member 103 is not contaminated.

[Example 2]
Based on the elastic roller DR3, charged cleaning members DR3-2 to DR3-5 having different Sm were prepared. Table 9 shows the surface shape of the roller, and Table 10 shows the correlation between the Smc of the electrostatic cleaning members DR3 to DR3-5 and the average primary particle diameter D of the inorganic fine particles. Table 11 shows the results of the printing durability test and evaluation similar to those in Example 1.

  From Tables 10 to 11, it is found that when the Smc of the charging cleaning member is 1E2 to 1E4 times the average particle diameter D, it is suitable for suppressing the contamination of the charging roller 102.

[Example 3]
DR3 was used as the charging cleaning member, and inorganic fine particles E were used.

  The same evaluation as in Example 1 was performed by using a spring, a spacer, and the like and shaking the pressure for bringing the charging cleaning member DR3 into contact with the charging roller 102. The results are shown in Table 12 below.

  From Table 12, good results were obtained when the charging cleaning member contacted the charging roller 102 at 2 to 10 g / cm. If the contact pressure is smaller than the above range, the cleaning ability is lowered. On the other hand, if it is too high, the charging cleaning member may sag, the charging roller surface may be worn out, or filming may occur on the charging roller surface.

[Example 4]
The same evaluation as in Example 3 was performed except that the drive system of the charging cleaning member was removed, the charging roller was driven, and the charging cleaning member was driven at a constant speed. The results are shown in Table 13.

  Compared with Table 12, wear of the charging cleaning member and filming of the charging roller are reduced. In particular, the latitude on the high voltage side is widened, and the mechanism of the charging means is simplified and the cost is reduced by removing the drive system. Is advantageous.

  Further, the charging cleaning member may be driven with a peripheral speed difference with respect to the charging roller. The value of the peripheral speed difference can be appropriately selected depending on the charging cleaning member to be used, the contact pressure, and the like.

  In this example, the charging cleaning member uses DR3 as described above, and uses a bearing in which a load is applied to the inner side of the charging cleaning member holder H103 (FIG. 7) (the portion sliding with the charging cleaning member 103). The roller 102 is rotated at a speed of 95 to 98%. Evaluation similar to the above was performed with this configuration. As a result, good results were obtained as shown in Table 14.

[Example 5]
Using various types of urethane rubbers having different hardness Z, various charging cleaning members Rz6 to 9 were prepared by shaking the surface Rz.

  Table 15 shows the results of the same evaluation as in Example 3 using the charging cleaning members DR1, DR3, DR5 and the charging cleaning members DR6-9.

  The description in each column of Table 15 is “dirt resistance” / “wear and tear of the charging cleaning member and charging roller”. From Table 15, when the product of Z × Rz is in the range of 10 to 500, compared with the charging cleaning member DR1 (Z × Rzc = 4) and the charging cleaning member DR9 (Z × Rzc = 580), Dirt resistance and wear of the charging cleaning member and charging roller on the high pressure side were also suppressed. Therefore, very good results were obtained.

[Example 6]
The surface shape of the charging cleaning member DR3 was created using a mold so as to be formed in a polygon as shown in FIG. 6A to obtain a charging cleaning member DR10. That is, the surface of the charging cleaning member is composed of a plurality of polygons.

  Further, as shown in FIG. 6B, the surface of the charging cleaning member was cut non-parallel to the length of the charging cleaning member to obtain a charging cleaning member DR11. That is, the surface of the charging cleaning member is provided with irregularities, and the arrangement of the irregularities is a charging cleaning member that is non-parallel to the moving direction of the surface of the charging roller and the image carrier.

  Table 16 shows the results of the same evaluation as in Example 2 using the above-described charging cleaning members DR10 and DR11. The description in the column conforms to Table 15.

  From Table 16, a more favorable result was obtained with a system having a polygonal surface.

[Example 7]
<Production Examples TR1 to TR5 of Charging Cleaning Member>
As a charging cleaning member, a single-foam foaming roller (single-bubble) with a foaming amount changed on a cored bar having an outer diameter of 7 mm (φ7) and a length of 350 mm as required by a known method such as heat compression and cutting Rollers; TR1-5) were prepared.

  About the created charging cleaning members TR1 to TR5, the surface is observed with a laser microscope, and from the average hole diameter L and the number of holes, the area occupied by the holes in the field of view corresponding to the outer diameter of the charging cleaning member is The pore density was determined.

  The prepared charging cleaning members TR1 to TR5 were set to have an Asker-C hardness (Z) of 20 ± 3 degrees and an average pore diameter of 50 to 100 μm.

  The results of the same evaluation as in Example 3 are shown in Table 17. The description in the column conforms to Table 15.

  From Table 17, good results were obtained when the pore density was 20 to 80%. In TR4 having a low hole density, uneven cleaning may occur, or filming may occur in the charging roller in part. On the other hand, in TR5 having a high hole density, the cleaning member itself may be worn out.

  Further, charging cleaning members TR6 to 10 having hardness Z and hole density equivalent to those of the charging cleaning member TR1 and different hole diameters Dc were prepared. Similarly, charging cleaning members TR11 to TR15 having the same Z as the charging cleaning member TR2 and different Dc in hole density, and charging cleaning members TR16 to TR20 having the same Z as the charging cleaning member TR3 and different Dc from the hole density, respectively. Created.

  As a result of performing the same evaluation using the charging cleaning members TR6 to 20 and the inorganic fine particles A to M, it is good when the average pore diameter Dc is 10 to 300 μm, particularly 1E2 to 1E4 times the average particle diameter D of the inorganic fine particles. Cleanability and durability were obtained.

[Example 8]
As the charge cleaning member, in addition to the charge cleaning members TR1 to TR5, the average hole diameter Dc and the hole density were adjusted, and foamed rollers having different hardness Z were prepared.

  As a result of performing the same evaluation as in Example 5, when the product of Z × Dc is in the range of 10 to 500, dirt resistance on the low pressure side, wear of the charging cleaning member and charging roller on the high pressure side are suppressed, Good results were obtained.

[Example 9]
<Production Examples RR1 to RR5 of the charging cleaning member> (pore density of the foaming roller)
As a charging cleaning member, a single-bubble open-cell roller (RR1) in which the foaming amount is changed on a cored bar having an outer diameter of 7 mm (φ7) and a length of 350 mm by a known method such as heat compression and cutting as necessary. To 5).

  These open cell rollers RP1 to RP5 have open cell cells in which a plurality of (about 1 to 5) cells are connected.

  In the open cell material, the pores continue to the inside of the electrostatic cleaning member, but the pore density of the portion corresponding to the outer diameter of the electrostatic cleaning member was determined in the same manner as the single bubble roller.

  As a result of the same evaluation as in Example 7, when the pore density is 20 to 80%, the average pore diameter Dc is about 10 to 300 μm, particularly 1E2 to 1E4 times the average particle diameter D of the inorganic fine particles. At that time, good cleaning ability and durability were obtained.

[Example 10]
Instead of the surface layer of the charging roller 102 used in Examples 1 to 8, a roller having a surface layer containing a polysiloxane having an alkyl fluoride group and an oxyalkylene group was prepared as the charging roller 102. The surface layer was prepared as follows.

-Glycidoxypropyltriethoxysilane (GPTES) 27.84 g (0.1 mol) as a hydrolyzable silane compound
・ Methyltriethoxysilane (MTES) 17.83 g (0.1 mol)
Tridecafluoro-1,1,2,2-tetrahydrooctyltriethoxysilane (FTS, carbon number 6 of perfluoroalkyl group) 7.68 g (0.0151 mol (equivalent to 7 mol% with respect to the total amount of hydrolyzable silane compound) ))
・ Water 17.43g
-Ethanol 37.88g
And mix.

  And the condensate I of a hydrolysable silane compound was obtained by stirring at room temperature and then performing a heating reflux for 24 hours.

  By adding this condensate I to a mixed solvent of 2-butanol / ethanol, a condensate-containing alcohol solution II having a solid content of 7% by mass was prepared.

  0.35 g of an aromatic sulfonium salt (trade name: Adekaoptomer SP-150, manufactured by Asahi Denka Kogyo Co., Ltd.) as a photocationic polymerization initiator is added to 100 g of this condensate-containing alcohol solution II. Add to Solution II. In this way, a surface layer coating solution III was prepared.

Next, the surface layer coating liquid III is ring-coated on the charging roller without the surface layer, and this is irradiated with ultraviolet light having a wavelength of 254 nm so that the integrated light quantity becomes 9000 mJ / cm ^2. III is cured (cured by crosslinking reaction) and dried. As a result, a surface layer was formed to obtain a charging roller CR-1. When the surface layer thickness of CR-1 was observed by SEM, it was 100 nm.

  Furthermore, by controlling the solvent concentration of the condensate-containing alcohol solution II, the viscosity of the surface layer coating liquid III was adjusted to prepare charging rollers CR-2 to CR-5 having different surface layer thicknesses.

  Other methods for adjusting the surface layer pressure include controlling the wettability to the surface layer coating liquid III by treating the surface of the charging roller before coating with ultraviolet rays, or using spacer particles for controlling the film thickness. There are ways to do it.

  The surface shapes of the created charging rollers CR-1 to CR-5 were the same as those of the charging rollers used in Examples 1-9. The same evaluation as in Example 3 was performed except that the CR-1 to CR-5 were used as the charging roller 102. The results are shown in Table 18. The description in the table is the antifouling / charge cleaning member and the wear of the charging roller. For reference, the results of Example 3 are also shown.

  Cleaning efficiency or durability was improved by the charging rollers CR-1 to CR-5. Particularly in the system using CR-1 to 3 having a surface layer thickness of 0.1 to 1 μm, not only the cleaning efficiency is improved, but also the wear of the charging cleaning member and the charging roller itself is reduced, which is very good. Results were obtained.

[Example 11]
Charged cleaning members TR1 ′ to TR7 ′ prepared by compressing the foamed member foamed under various conditions in the longitudinal direction so that the post-compression hardness, average pore diameter, and pore density are equal to those of the charged cleaning member TR2. It was created.

  In addition, since the vacancies observed from the surface of the charging cleaning members TR1 'to 7' are not circular, the average area of the vacancies was obtained, and the equivalent circle diameter of the vacancies was defined as the vacancy diameter Dc.

  Table 19 shows the results of the same evaluation as in Example 7 using the above-described charging cleaning member. The description in the table conforms to Table 17.

  From Table 19, the same applies to the charge cleaning member compressed in the longitudinal direction, particularly the charge cleaning member (TR3 ′ to 6 ′) having a short diameter La / long diameter Lb ratio of 0.6 to 0.9. Also in terms of hardness, hole diameter, hole density, etc., it has a cleaning capability equal to or higher than that of a non-compressed charged cleaning member (nothing). Therefore, even better durability was obtained.

[Example 12]
A spacer was provided at the end of the charging roller used in Example 1, the gap interval α at the closest part was set to 50 μm, and the proximity charging unit 102 as shown in FIG. 4 was set.

  In addition, the charging roller hardness is changed to an Asker C hardness of 70 degrees, and the charging roller is provided with a driving means (not shown) to rotate in the forward direction at the same peripheral speed as the image carrier 101. I tried to drive.

  These charging rollers were used, and the same evaluation as in Example 1 was performed. Better results than in Example 1 were obtained. In particular, when the roller-shaped charging unit 102 was driven to rotate, very good results were obtained.

  It is considered that the proximity charging method or the drive-type proximity charging generates an air flow in the vicinity of the surface of the image carrier 101 so that the airflow or the like works well.

[Example 13]
For the image carrier P01, a support 101a (FIG. 10) in which the type of the R-shaped tool was changed, and a support 101a in which the setting angle, the penetration amount, and the pitch of the flat tool were controlled were prepared.

  A positively charged a-Si photosensitive member was formed on the support 101a by RF-CVD. The created photoreceptor was polished as it was or with a commercially available wrapping tape or the like to obtain image carriers P02 to P08.

  Table 20 shows the surface shape of the obtained image carrier, and Table 21 shows the ratio of Smd of the image carrier to Smc of the charging cleaning members DR1 to DR5.

  These image carrier and charge cleaning member were used, and inorganic fine particles E were used so that the charge cleaning member was driven by the charging roller and followed at a constant speed. The pressure at which the charging cleaning member abuts on the charging roller was set to 2 g / cm. The other evaluations were the same as in Example 4. Table 22 shows the results of evaluating the anti-smudge property of the charging roller, and Table 23 shows the results of evaluating the wear of the charging cleaning member and the charging roller.

  From Tables 20 to 23, when 0.1 ≦ Rzd ≦ 1.0 μm and 5 ≦ Smd ≦ 30 μm, very good antifouling performance was obtained, and wear was suppressed.

  Even better results were obtained when Smc / Smd was not a natural number. Further, the average outer diameter of the charging cleaning member was prepared in increments of 1 mm from φ4 to φ20 in addition to φ12 of the previous examples, and the same evaluation was performed. As a result, when [average outer diameter of charging roller] / [average outer diameter of charging cleaning member] is not an integer, the growth of dirt adhered on the charging roller in the circumferential direction is suppressed, and good results are obtained. It was.

[Example 14]
The surface roughness Rz (hereinafter Rzd) of the image carrier is 0.1 to 1.0 μm, Sm (hereinafter Smd) is 5 to 30 μm, the ratio of Smd to Dc is not an integer, and charging cleaning is performed. The ratio of the average outer diameter of the member and the average outer diameter of the charging roller is not an integer. For the single-cell and continuous-cell charging cleaning member, the foaming process is controlled, and the average has various average pore diameters Dc [μm]. A cleaning member having an outer diameter of φ12 was prepared. Further, the same average pore diameter and outer diameter of φ4 to φ20 were prepared in 1 mm increments.

  As a result of performing the same evaluation as in Example 13, when 0.1 ≦ Rzd ≦ 1.0 μm and 5 ≦ Smd ≦ 30 μm, very good antifouling performance was obtained and wear was suppressed.

  When Dc / Smd is not a natural number, a better result was obtained. Further, as in Example 13, when [Average outer diameter of charging roller] / [Average outer diameter of charging cleaning member] is not an integer, the growth of dirt attached on the charging roller in the circumferential direction is suppressed, which is good. Results were obtained.

  In each of the above embodiments, an electrophotographic photosensitive member is used as the image carrier, but the image carrier can also be an electrostatic recording dielectric.

  In addition, the developer image formed and supported on the image carrier is primarily transferred to an intermediate transfer member serving as a first transfer member, and then secondarily transferred to a transfer material P serving as a second transfer member. An image forming apparatus configuration can also be used.

  The rotatable charging member can be in the form of a belt as well as a roller.

Schematic configuration diagram of image forming apparatus of embodiment example (1) Schematic configuration diagram of image forming apparatus of embodiment example (2) Schematic configuration diagram of image forming apparatus of embodiment example (No. 3) Schematic configuration diagram of image forming apparatus of embodiment example (4) Schematic diagram of an example of the surface shape of the electrostatic cleaning member Schematic diagram of another example of the surface shape of the electrostatic cleaning member (A: example composed of polygons, B: example provided with irregularities by cutting) Explanatory drawing of each pressing means of charging member and charging cleaning member The figure which shows the concept of the porosity of the surface shape of an electrostatic cleaning member Schematic diagram of the durability chart used for evaluation of the examples Schematic model diagram showing layer structure of a-Si photoconductor -Schematic model showing the relationship between the support shape and surface shape of the Si photoconductor SEM photograph of an example of inorganic particles S Conceptual figure of rectangular parallelepiped shape Model diagram showing the relationship between the surface shape of the image carrier and the charging cleaning member The figure which shows an example of the manufacturing method of an electrostatic cleaning member The figure which shows an example of the compression method of an electrostatic cleaning member Model diagram for explaining the relationship between the cell shape of foam and the hardness and strength of the foam member Model diagram showing an example of the cell shape after the compression process

Explanation of symbols

  DESCRIPTION OF SYMBOLS 101; Image carrier, 102; Charging means, 103; Charge cleaning member, 104; Latent image forming exposure means, 105; Developing means, 106; Transfer means, 107; Cleaning means, 108; DESCRIPTION OF SYMBOLS 110; Cleaning member 111; Inorganic particle supply and rubbing means, 115; Inorganic particle container, 101a; Support, 1002b; Photosensitive layer, 101c; Photoconductive layer, 101d; Surface layer, 101e and 101f; 1501; cylindrical container for compression, 1502 and 1503; pressure member, P: transfer material, X: traveling direction of image carrier, S: inorganic particles

Claims (20)

A rotatable image carrier that carries the developer, a rotatable charging member that is disposed opposite the image carrier and charges the image carrier, and the developer that is covered by the image carrier. In an image forming apparatus having a transfer means for transferring to a transfer body,
Inorganic particle supply means for supplying inorganic particles having perovskite crystals having an average particle diameter D of 0.03 to 0.50 [μm] to the surface of the image carrier;
Rubbing means for rubbing the surface of the image carrier after the developer is transferred to the transfer body in the presence of the inorganic particles;
A rotatable cleaning member that contacts the charging member and cleans the surface of the charging member;
Have
The image forming apparatus, wherein the cleaning member is an elastic member, and the surface roughness Rzc is 5 to 500 times the average particle diameter D.   The image forming apparatus according to claim 1, wherein a surface roughness Smc of the cleaning member is 1E2 to 1E4 times the average particle diameter D. A rotatable image carrier that carries the developer, a rotatable charging member that is disposed opposite the image carrier and charges the image carrier, and the developer that is covered by the image carrier. In an image forming apparatus having a transfer means for transferring to a transfer body,
Inorganic particle supply means for supplying inorganic particles having perovskite crystals having an average particle diameter D of 0.03 to 0.50 [μm] to the surface of the image carrier;
Rubbing means for rubbing the surface of the image carrier after the developer is transferred to the transfer body in the presence of the inorganic particles;
A rotatable cleaning member that contacts the charging member and cleans the surface of the charging member;
Have
The image forming apparatus according to claim 1, wherein the cleaning member is a foamed member and has a surface pore density of 20 to 80%.   The image forming apparatus according to claim 3, wherein an average pore diameter Dc of the cleaning member is 1E2 to 1E4 times the average particle diameter D.   The image forming apparatus according to claim 1, wherein the cleaning member contacts the charging member with a pressure of 2 to 10 g / cm.   When the hardness of the cleaning member is Z, 10 ≦ Z × RD ≦ 500 (RD is surface roughness Rzc when the cleaning member is an elastic member, and average pore diameter Dc when the cleaning member is a foam member). The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus.   7. The image forming apparatus according to claim 1, wherein the image bearing member has a surface roughness Rzd of 0.1 to 1.0 [mu] m and a surface roughness Smd of 5 to 30 [mu] m.   The image forming apparatus according to claim 1, wherein the cleaning member follows the movement of the surface of the charging member.   The image forming apparatus according to claim 1, wherein a surface of the cleaning member includes a plurality of polygons.   The unevenness is provided in the cleaning member, and the array of the unevenness is non-parallel to the moving direction of the surface of the charging member and the image carrier. Image forming apparatus.   The image forming apparatus according to claim 1, wherein an average particle diameter D of the inorganic particles is 0.10 to 0.30 [μm].   The image forming apparatus according to claim 1, wherein the cleaning member has a peripheral speed difference with respect to the charging member.   The image forming apparatus according to claim 1, wherein a pressure at which the charging member is brought into contact with the image carrier is 30 g / cm or less.   The image forming apparatus according to claim 1, wherein the surface layer of the charging member contains polysiloxane having an alkyl fluoride group and an oxyalkylene group.   The image forming apparatus according to claim 14, wherein the surface layer has a thickness of 0.1 to 1 μm.   The image forming apparatus according to any one of claims 1 to 15, wherein the cleaning member is formed by a compression process at least in a longitudinal direction.   The image forming apparatus according to claim 3, wherein the shape of the cell of the cleaning member is a product created through a compression process in the longitudinal direction.   The image forming apparatus according to claim 17, wherein a ratio of a minor axis / major axis of the cell of the cleaning member is 0.6 to 0.9.   The image forming apparatus according to claim 1, wherein the charging member is opposed to the image carrier with a gap.   The image forming apparatus according to claim 1, wherein the inorganic particles have a circularity of 0.930 or less.