Electro-photographic image formation apparatus and process cartridge

Abstract

To provide an electro-photographic image formation apparatus that can maintain the excellent cleaning performance on the surface of an electro-photographic photoreceptor over a long period of time.SOLUTION: An electro-photographic image formation apparatus includes: an electro-photographic photoreceptor as a charging object; a cleaning member that touches the surface of the electro-photographic photoreceptor; and a plasma actuator. The plasma actuator includes: a dielectric body; a first electrode which is provided on the first surface of the dielectric body; and a second electrode which is arranged with the dielectric body held between the first electrode and itself. The plasma actuator applies the AC voltage between the first electrode and the second electrode to generate an inductive flow from the edge of the first electrode along an exposed part that is not covered by the first electrode of the first surface of the dielectric body. The plasma actuator is arranged so that the inductive flow can be supplied directly to the surface of the electro-photographic photoreceptor, and controls the potential of transfer residual toner on the surface of the electro-photographic photoreceptor.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure is directed to an electrophotographic image forming apparatus and a process cartridge. [Background technology]

[0002] Electrophotographic image forming apparatuses (hereinafter also referred to as "electrophotographic apparatuses") are equipped with various cleaning members to remove toner and external additives remaining on an image carrier after a toner image is transferred from an image carrier such as a photoconductor onto a receiving body such as paper or an intermediate transfer body.

[0003] In recent years, with the trend toward higher image quality in electrophotographic devices, toner particles have become smaller and more spherical, making it more difficult for cleaning members to stop the toner remaining on the image carrier, and so higher cleaning performance is being demanded of various cleaning members. Furthermore, as electrophotographic devices are becoming longer in life, there is a demand for so-called light pressure cleaning technology, in which cleaning members are used with a weak contact pressure in order to suppress wear on the drum and cleaning members due to long-term use and to suppress the load on the photosensitive drum motor.

[0004] As a cleaning member, Patent Document 1 discloses a cleaning blade having a polyurethane elastomer for cleaning residual toner on a photosensitive drum, and Patent Document 2 discloses a cleaning blade having a conductive portion as a cleaning blade that also functions as a charging blade. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2016-014740 A [Patent Document 2] Japanese Patent Application Publication No. 11-202597 Summary of the Invention [Problem to be solved by the invention]

[0006] The present inventors attempted to perform a durability evaluation of the cleaning members according to Patent Documents 1 and 2, which corresponds to long-term use in an electrophotographic process having a light pressure cleaning configuration. In general, in the electrophotographic image forming process, the polarity of the voltage applied to the charging member and the voltage applied to the transfer roller are opposite. The substances to be cleaned, such as the toner that was not transferred to the paper or intermediate transfer body (hereinafter also referred to as "transfer residual toner"), paper powder, and fillers, are discharged by the transfer roller and have a certain amount of charge, and are strongly attached to the photosensitive drum surface by electrostatic attraction, so that it may be difficult to scrape them off with light pressure.

[0007] The cleaning blade according to Patent Document 1 improves cleaning performance by controlling the contact pressure of the cleaning blade against the photosensitive drum by controlling the chemical structure of the urethane elastomer contained in the elastic portion. According to the study by the present inventors, when the cleaning blade according to Patent Document 1 is used for a long period of time and in a light pressure cleaning configuration, the toner and external additives slip through, contaminating the charging member, and the contaminated portion may become apparent as streaks on the image.

[0008] Furthermore, even with the dual-purpose charging cleaning blade having a conductive portion according to Patent Document 2, it was difficult to prevent toner and external additive stains from slipping through over long-term use. If the stains slip through, the toner and external additives may adhere to the conductive portion responsible for charging due to electrostatic attraction, and the relevant portions may prevent discharge, resulting in poor image quality.

[0009] In view of the above, at least one aspect of the present disclosure is directed to providing an electrophotographic image forming apparatus capable of stably exerting excellent cleaning performance for the surface of a photosensitive drum for a long period of time.Further, at least one aspect of the present disclosure is directed to providing a process cartridge capable of exerting excellent cleaning performance for the surface of a photosensitive drum for a long period of time. [Means for solving the problem]

[0010] According to at least one aspect of the present disclosure, there is provided an electrophotographic image forming apparatus including an electrophotographic photosensitive member as a member to be charged, a cleaning member in contact with a surface of the electrophotographic photosensitive member, and a plasma actuator, The plasma actuator comprises: A dielectric material; a first electrode provided on a first surface of the dielectric; a second electrode provided on the first electrode with the dielectric interposed therebetween; By applying an AC voltage between the first electrode and the second electrode, the plasma actuator generates an induced flow from an edge of the first electrode along an exposed portion of the first surface of the dielectric material that is not covered by the first electrode; The plasma actuator is disposed so as to be capable of directly supplying the induced flow to the surface of the electrophotographic photosensitive member, and controls the potential of the transfer residual toner on the surface of the electrophotographic photosensitive member, thereby providing an electrophotographic image forming apparatus.

[0011] According to at least one aspect of the present disclosure, there is provided a process cartridge detachably mountable to an electrophotographic image forming apparatus, comprising: The process cartridge includes an electrophotographic photosensitive member, a cleaning member in contact with the surface of the electrophotographic photosensitive member, and a plasma actuator. The plasma actuator comprises: A dielectric material; a first electrode provided on a first surface of the dielectric; a second electrode 2 provided on the first electrode with the dielectric sandwiched therebetween; By applying an AC voltage between the first electrode and the second electrode, the plasma actuator generates an induced flow from an edge of the first electrode along an exposed portion of the first surface of the dielectric material that is not covered by the first electrode; The plasma actuator is disposed so as to be capable of directly supplying the induced flow to the surface of the electrophotographic photosensitive member, and controls the potential of the transfer residual toner on the surface of the electrophotographic photosensitive member. A process cartridge is provided. Effect of the Invention

[0012] According to at least one aspect of the present disclosure, it is possible to obtain an electrophotographic image forming apparatus capable of stably exerting excellent cleaning performance for the surface of a photosensitive drum for a long period of time. Also, according to at least one aspect of the present disclosure, it is possible to obtain a process cartridge capable of exerting excellent cleaning performance for the surface of a photosensitive drum for a long period of time. [Brief description of the drawings]

[0013] [Figure 1] 1 is a schematic diagram showing a configuration of a plasma actuator and a cleaning member according to an embodiment of the present disclosure. [Diagram 2] FIG. 1 is a schematic diagram showing an example of the configuration of a plasma actuator. [Diagram 3] FIG. 1 is a schematic diagram showing an example of the configuration of a plasma actuator. [Figure 4] FIG. 1 is an explanatory diagram of charging of dirt by induced flow. [Diagram 5] FIG. 4 is an explanatory diagram of overlap between a first electrode and a second electrode. [Figure 6] FIG. 13 is an explanatory diagram of suppression of electric field concentration by overlapping. [Figure 7] FIG. 4 is an explanatory diagram of the uneven shape of the edge of the first electrode. [Figure 8] FIG. 4 is an explanatory diagram regarding the arrangement of a plasma actuator and a cleaning member. [Figure 9] FIG. 2 is a schematic diagram of an electrophotographic process cartridge. [Figure 10] FIG. 1 is a schematic diagram of an electrophotographic apparatus. [Figure 11] An explanatory diagram of how wind speed is measured using PIV. [Figure 12] An example of incorporating a plasma actuator into a cleaning component. [Figure 13] An example in which the induced flow is not directly supplied to the photoconductor drum surface. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, with reference to the drawings, specific examples of the embodiments for carrying out this disclosure will be described. However, the dimensions, materials, shapes, and relative positions of the components described in these embodiments should be appropriately changed depending on the configuration of the member to which the disclosure is applied and various conditions. In other words, it is not intended to limit the scope of this disclosure to the following embodiments.

[0015] In the present disclosure, the description of a numerical range such as "XX or more and YY or less" or "XX to YY" means a numerical range including the lower and upper limits, which are the endpoints, unless otherwise specified. When a numerical range is described in stages, the upper and lower limits of each numerical range can be combined in any combination.

[0016] In electrophotographic devices, the toner and external additives remaining on the photosensitive drum after the transfer process, as well as the paper dust and fillers (hereinafter collectively referred to as "contaminants") contained in the printing paper that has been transferred to the photosensitive drum, become charged by discharge during the transfer process and adhere to the surface of the photosensitive drum due to electrostatic attraction. The inventors recognized that because the surface of the photosensitive drum often retains a surface potential of 100 V or more even after the transfer process, the electrostatic attraction between the dirt and the drum is strong, and that in a light-pressure cleaning system, it is difficult to scrape off the dirt with a cleaning member.

[0017] As a result of their investigations, the inventors have found that by irradiating the residual toner to be scraped off by the cleaning member with an induced flow having a charge and controlling the potential of the residual toner, it is possible to maintain excellent cleaning performance for a long period of time even when the contact pressure of the cleaning member against the electrophotographic photosensitive member is light.

[0018] Specifically, at least one aspect of the present disclosure is an electrophotographic image forming apparatus including an electrophotographic photosensitive member as a member to be charged, a cleaning member in contact with a surface of the electrophotographic photosensitive member, and a plasma actuator, The plasma actuator comprises: A dielectric material; a first electrode provided on a first surface of the dielectric; a second electrode provided on the first electrode with the dielectric interposed therebetween; By applying an AC voltage between the first electrode and the second electrode, the plasma actuator generates an induced flow from an edge of the first electrode along an exposed portion of the first surface of the dielectric material that is not covered by the first electrode; The plasma actuator is disposed so as to be capable of directly supplying the induced flow to the surface of the electrophotographic photosensitive member, and controls the potential of the transfer residual toner on the surface of the electrophotographic photosensitive member, in the electrophotographic image forming apparatus.

[0019] Here, the control of the potential of the transfer residual toner by the plasma actuator includes, for example, at least one selected from the group consisting of the de-electrification of the transfer residual toner by the induced flow, and the charging of the transfer residual toner by the induced flow to the same polarity as the polarity of the surface of the electrophotographic photosensitive member. and charging the polarity of the transfer residual toner by the induced flow to the same polarity as the polarity of the surface of the electrophotographic photosensitive member. At least one selected from the group consisting of this may be simply referred to as "electric de-ionization and / or charging".

[0020] The present inventors believe that the reason why the above electrophotographic apparatus can significantly improve the cleaning performance at light pressure is as follows. The jet-like induced flow generated by the plasma actuator contains a mixture of positive, negative, and neutral charges, so it is possible to cancel out either the positive or negative polarity of the irradiated object and eliminate the charge. The electrophotographic device supplies the induced flow to the dirt, such as the residual toner after transfer, before the dirt enters the contact portion between the cleaning member and the electrophotographic photosensitive member. Therefore, the induced flow reduces the charge amount of the dirt on the photosensitive drum, and the electrostatic attraction between the dirt and the drum can be greatly reduced, so that the adhesion force between the dirt and the photosensitive drum can be suppressed. In addition, since the induced flow of the plasma actuator is also supplied to the photosensitive drum, the photosensitive drum surface is also simultaneously de-electrified, and the electrostatic attraction between the dirt and the photosensitive drum is further reduced.

[0021] Furthermore, by moving and rolling the dirt on the drum with the induced flow, which is a jet flow, it is possible to disperse the dirt on the drum. Also, by physically moving and rolling the dirt with the induced flow, the induced flow can also be applied to the surface of the dirt that was facing the drum surface, making it possible to eliminate static electricity from most of the dirt surface. In addition, as will be described in detail later, depending on the voltage applied to the plasma actuator, the dirt can be charged to a desired polarity. In this case, by supplying an induced flow to the dirt that enters the contact portion, the photosensitive drum surface and the dirt can be charged to the same polarity, and the electrostatic attraction between the photosensitive drum surface and the dirt can be reduced.

[0022] For the above reasons, it is believed that an electrophotographic device equipped with a plasma actuator and a cleaning member can greatly reduce the electrostatic attraction between dirt and the photosensitive drum, and improve the performance of the cleaning member in blocking dirt. As a result, it is believed that it is possible to improve the light pressure cleaning performance over a long period of time.

[0023] 1A to 1C, an electrophotographic apparatus 101 according to one embodiment of the present disclosure will be described below. Figures 1A to 1C are schematic diagrams showing the surface of a photosensitive drum 104 as an electrophotographic photosensitive member, a cleaning member 103, a plasma actuator (plasma generating device) 102, and the like. As shown in Fig. 1A, the electrophotographic apparatus includes a photosensitive drum 104 as a member to be charged, a cleaning member 103 in contact with the surface of the photosensitive drum, and a plasma actuator 102. As shown in Fig. 1B, the cleaning member 103 and the plasma actuator 102 may be integrated together, or as shown in Fig. 1C, the plasma actuator 102 may be incorporated into the cleaning member 103. The rotation direction is the same as that of the photosensitive drum 104.

[0024] 1A to 1C, dirt 10 present on a photosensitive drum 104 penetrates into a contact portion 11 between a cleaning member 103 and the photosensitive drum 104, and is cleaned by the cleaning member 103. Furthermore, the plasma actuator 102 is disposed so as to supply an induced flow 106 containing electric charge to the dirt 10 penetrating into the contact portion 11 before the dirt penetrates. As a result, the cleaning member 103 can eliminate and / or charge the dirt 10 that enters the cleaning member 103, and can also physically roll the dirt 10. As a result, the electrostatic attraction with the photosensitive drum surface can be reduced, and the cleaning performance of the cleaning member 103 can be improved.

[0025] An example of an electrophotographic apparatus is specifically shown in Fig. 2. The electrophotographic apparatus 101 includes a plasma actuator 102 and a photosensitive drum 104. In Fig. 2, reference numeral 10 denotes dirt (residual toner after transfer) remaining on the photosensitive drum surface 104-1, and reference numeral 106 denotes an induced flow.

[0026] <Plasma actuator> 3 shows a cross-sectional structure of one embodiment of plasma actuator 102. Plasma actuator 102 includes a first electrode 203 on one surface (hereinafter also referred to as the "first surface") of dielectric 201. Plasma actuator 102 also includes a second electrode 205 provided on first electrode 203 with dielectric 201 sandwiched therebetween. Plasma actuator 102 may have a configuration in which second electrode 205 is provided on a surface (hereinafter also referred to as the "second surface") opposite to the first surface, for example. Plasma actuator 102 is a so-called dielectric barrier discharge (DBD) plasma actuator (hereinafter may be simply referred to as "DBD-PA").

[0027] 2, reference numeral 206 denotes a dielectric substrate, reference numeral 207 denotes an AC power source, and reference numeral 208 denotes a DC power source. The dielectric substrate 206 is a substrate for embedding the second electrode 205 in the thickness direction of the plasma actuator so as not to generate an induced current from the end face of the second electrode. In other words, it is sufficient that the first electrode 203 and the second electrode 205 are provided with the dielectric 201 therebetween, and for example, the second electrode 205 may be embedded in the dielectric 201.

[0028] In the plasma actuator 102, a first electrode 203 and a second electrode 205 are disposed with a dielectric 201 sandwiched between them, for example, offset from each other diagonally. By applying an AC voltage between these electrodes (between both electrodes), a plasma 202 is generated from the first electrode 203 toward the second electrode 205. Then, an induced flow 106, which is a jet-like flow by the plasma (surface plasma) 202, is induced from the edge 204 of the first electrode 203 along an exposed portion (portion not covered by the first electrode) 201-1 of the first surface of the dielectric 201.

[0029] By disposing the first electrode 203 and the second electrode 205 on either side of the dielectric 201 so as to be offset diagonally from each other, the induced flow 106 can be easily supplied in a desired direction, and cleaning performance can be improved. Even if the first electrode 203 and the second electrode 205 are not disposed diagonally from each other, it is possible to prevent the induced flow from being generated in any direction other than the desired direction by providing a dielectric, for example, as shown in FIG. 12 described later.

[0030] The plasma actuator 102 is disposed on a substrate 107 in FIG. 2 so that the induced flow 106 is supplied to the photosensitive drum surface 104-1. The substrate 107 is not particularly limited, and may be a known material such as ABS (acrylonitrile butadiene styrene copolymer) resin. As shown in FIG. 1B, the plasma actuator 102 may be provided on a cleaning member 103 so that the induced flow 106 is supplied to the photosensitive drum surface 104-1.

[0031] That is, in this embodiment, the induced flow 106 having a charge from the plasma actuator 102 is directly supplied to the surface of the photosensitive drum. As a result, both the surface of the photosensitive drum and any dirt remaining on the surface of the photosensitive drum can be discharged and / or charged.

[0032] The induced flow 106 flows in the direction of a jet-like flow caused by the surface plasma from the edge 204 of the first electrode 203 along the exposed portion 201-1 of the first surface of the dielectric 201, that is, in the direction from the edge 204 of the first electrode 203 along the exposed portion 201-1 of the first surface of the dielectric. This induced flow is a gas flow having a speed of about several m / s to several tens of m / s.

[0033] The velocity of the induced flow at a position 1.0 mm away from the tip of the plasma actuator in the supply direction of the induced flow, as measured by particle image velocimetry, is preferably 0.10 to 1.00 m / sec, more preferably 0.15 to 1.00 m / sec, even more preferably 0.15 to 0.60 m / sec, and even more preferably 0.20 to 0.40 m / sec. The position 1.0 mm away from the end refers to a position 1.0 mm from the tip 701a on the second electrode side in the supply direction of the induced flow on an extension line (line 700) from the edge of the first electrode of the plasma actuator in a direction along exposed portion 201-1 of the first surface of the dielectric, in Fig. 8A. By keeping the speed within the above range, it is possible to supply an induced flow sufficient for removing dirt and charging / discharging the photosensitive drum.

[0034] At the same time that the induced flow 106 is generated, a flow that draws in air is also generated toward the first electrode. Therefore, due to the action of the jet-like flow caused by the surface plasma 202 and the air suction flow, an induced flow 106 containing electric charge is generated from the edge 204 of the first electrode 203 along the surface of the dielectric 201. The plasma actuator 102 is disposed so that the induced flow 106 is supplied directly to the surface 104-1 of the photosensitive drum, and at the same time, is supplied directly to dirt present on the photosensitive drum. The induced flow 106 contains positively and negatively charged particles generated by ionization caused by the discharge of the plasma actuator, as well as electrically neutral particles. As described above, it is believed that the photosensitive drum and dirt can be neutralized by the mixed charges.

[0035] As described above, depending on the voltage applied to the plasma actuator 102 and the photosensitive drum, it is also possible to charge the photosensitive drum 104 and the stain 10 to a desired polarity. For example, a positive or negative DC voltage may be superimposed between the first electrode 203 and the photosensitive drum 104. Due to the electric field formed by the DC voltage, among the positive and negative charges generated by ionization due to discharge, charges of the same polarity as the DC voltage can be preferentially supplied to the photosensitive drum surface 104-1 and the stain 10. That is, by superimposing an AC voltage and a DC voltage, the charge supplied to the photosensitive drum 104 can be controlled to charge the photosensitive drum surface 104-1 and the stains 10 on the photosensitive drum surface. In addition, the higher the applied DC voltage, the more charges of the same polarity as the applied voltage are supplied to the photosensitive drum surface 104-1, improving the charging ability.

[0036] 4, the stain 10, which has been charged by the transfer roller with a polarity opposite to that of the charging bias, is transported by the rotation of the photosensitive drum 104 and receives an induced flow 106 containing a charge. The stain 10-1 that has received the induced flow is charged to the same polarity as the photosensitive drum 104 by the charge contained in the induced flow. By charging the stain 10-1 and the photosensitive drum 104 to the same polarity, the electrostatic attraction between the stain 10-1 and the photosensitive drum 104 can be further reduced, and the cleaning performance of the cleaning member 102 can be further improved.

[0037] As described above, by supplying an induced flow 106 containing an electric charge generated by the plasma actuator 102 to dirt that enters the cleaning member, the dirt is neutralized or charged to the same polarity as the photosensitive drum, and the dirt is physically moved by the induced flow, thereby reducing the electrostatic attraction between the photosensitive drum surface and the dirt, and improving light-pressure cleaning performance.

[0038] In addition, whether or not the transfer residual toner and other contaminants have been discharged or charged to the same polarity as the photosensitive drum can be known by, for example, measuring the surface potential of the transfer residual toner group on the photosensitive drum or measuring the charge amount. Specifically, for example, by using a means for quantifying the charge amount distribution of the transfer residual toner group, which will be described later, it is possible to know that the transfer residual toner has been discharged. More specifically, for example, a method can be used to confirm the proportion of toner particles that have changed to the polarity opposite to polarity A after irradiation of the induced flow, among toner particles that have the same polarity as the polarity of the voltage applied to the transfer member (hereinafter also referred to as polarity A) before irradiation of the induced flow 106 on the transfer residual toner.

[0039] The amount of residual toner after transfer when checking the change in polarity is, for example, measured by the following method under transfer process conditions where the fog value is 5%. The change in the charge polarity of the residual toner due to the transfer can be measured. Specifically, the fog value can be measured, for example, as follows. First, while a solid black image is being printed, the printing operation is stopped, and the residual toner adhering to the photosensitive drum surface between the transfer member contact portion and the charging member contact portion is peeled off with tape (product name: CT18, manufactured by Nichiban Co., Ltd.). Next, the reflectance is measured with a reflection densitometer (product name: TC-6DS / A, manufactured by Tokyo Denshoku Co., Ltd.), and the reflectance of the tape is used as a reference. The amount of decrease (%) in reflectance when the light is turned on is measured and this is taken as the fog value.

[0040] Furthermore, for the transfer residual toner group under the transfer process conditions that result in the above fog value, the number ratio of the toner group that has changed from the same polarity as the polarity of the voltage applied to the transfer member to the opposite polarity before and after irradiation with the plasma actuator is measured. The number ratio is based on the number of toner particles that have the same polarity as the polarity of the voltage applied to the transfer member before irradiation. It is preferable that the change rate Δ after irradiation described below is 50% or more. It is more preferable that the change rate Δ is 80% to 100%. Within this range, the electrostatic attraction with the photosensitive drum can be suppressed, and the cleaning performance can be improved.

[0041] <Electrode placement> The arrangement of the electrodes will be described with reference to FIGS. 5A and 5B. FIG. 5A is a cross-sectional view passing through the dielectric, the first electrode 203, and the second electrode 205. FIG. 5B is a view of the plasma actuator seen through the surface side of the first electrode. When the first electrode 203 and the second electrode 205 arranged diagonally opposite each other are viewed from above in the cross-sectional view, it is preferable that the edge of the first electrode is present in the formation portion of the second electrode with the dielectric sandwiched between them. That is, as shown in FIG. 5B, when the plasma actuator is seen through the surface side of the first electrode, it is preferable that at least a part of the edge of the first electrode has an overlapping portion with the second electrode. In this way, it is preferable that the first electrode and the second electrode are provided so as to overlap with the dielectric sandwiched between them.

[0042] By overlapping the first and second electrodes with a dielectric between them, the distance between the electrodes is minimized and the electric field strength is maximized, which allows a strong induced flow to be generated. In this case, it is preferable to prevent dielectric breakdown when a voltage is applied in the portion where the first and second electrodes overlap with the dielectric between them.

[0043] In addition, if the edge of the second electrode is exposed, plasma may also be generated from the edge of the second electrode, and an induced flow may occur in the opposite direction to the induced flow 106 from the first electrode. It is preferable not to blow the induced flow to areas other than the surface of the charged body. Therefore, it is preferable not to generate an induced flow from the second electrode. Therefore, it is preferable that the second electrode 205 is covered with a dielectric such as a dielectric substrate 206 as shown in Figures 3 and 5A, or embedded in a dielectric 201 to prevent plasma generation from the edge of the second electrode.

[0044] From the viewpoint of uniformly discharging and charging dirt, it is preferable that the induced flow is generated from one side of the first electrode when the plasma actuator is viewed from the first electrode side. For example, it is preferable that the induced flow is generated in one direction toward the photoconductor surface from one side of the first electrode facing the surface of the photoconductor. The other side of the first electrode may be covered with a dielectric so that the induced flow is not generated from the other side of the first electrode. In addition, when the plasma actuator is viewed from the first electrode side, the side adjacent to the side generating the induced flow and the side of the second electrode may be in the same straight line (FIG. 5B).

[0045] <Overlap> 5A and 5B are explanatory diagrams of the overlap between the first electrode 203 and the second electrode 205 of the plasma actuator 102. They are cross-sectional views of the plasma actuator. The length of the overlapping portion between the edge of the first electrode and the edge of the second electrode is length A, and the overlapping portion is length B. The overlapping length is defined as positive. That is, when the plasma actuator is seen through from the surface side of the first electrode (FIG. 6B), the length A between the edge of the first electrode and the edge of the second electrode forming the overlapping portion is preferably 0 to 1000 μm, more preferably 80 to 1000 μm, even more preferably 100 to 1000 μm, and even more preferably 100 to 700 μm. By overlapping the first electrode and the second electrode, the convex shape of the electrode edges (described below) can be used to suppress electric field concentration, thereby making it possible to suppress streaks caused by uneven discharge on the image and uneven dirt adhesion caused by uneven induced flow.

[0046] The convex shape of the edge of the electrodes will now be described. Cross-sectional views and overhead views of the plasma actuator are shown in Figures 6A to 6D. When the two electrodes are separated and do not overlap as in Figure 6A, the electric field concentrates at the apex of the convex shape of the edge of the first electrode, which may cause unevenness in the discharge and the strength of the induced flow in the longitudinal direction (501a). On the other hand, by overlapping the two electrodes as shown in Figures 6B and 6D, the electric field strength formed between the two electrodes is governed by the thickness of the dielectric, and discharge unevenness in the longitudinal direction can be mitigated (501b). Furthermore, since local concentration of the electric field on the convex shape can be suppressed, insulation breakdown can be suppressed even when the distance between the two electrodes is short. Note that when the electrodes have a convex shape, the length A is the length between the edge of the first electrode closest to the second electrode and the edge of the second electrode closest to the first electrode.

[0047] <Electrode thickness> The thickness of the electrodes, both the first electrode and the second electrode, is not particularly limited, but can be 10 μm to 1000 μm. If it is 10 μm or more, the resistance of the electrode itself is low and plasma is easily generated. If it is 1000 μm or less, electric field concentration is likely to occur, making plasma easily generated.

[0048] <Electrode material> The materials constituting the first electrode and the second electrode are not limited as long as they are materials with good electrical conductivity and do not impede the effects of the present disclosure. For example, metals such as copper, aluminum, stainless steel, gold, silver, platinum, and the like, as well as those plated or vapor-deposited thereon, conductive carbon materials such as carbon black, graphite, and carbon nanotubes, and composite materials in which these are mixed with resins, etc., can be used. The materials constituting the first electrode and the second electrode may be the same or different.

[0049] Among these, from the viewpoint of avoiding electrode corrosion and achieving uniform discharge, the material constituting the first electrode is preferably aluminum, stainless steel, or silver, and for the same reason, the material constituting the second electrode is preferably aluminum, stainless steel, or silver.

[0050] <Electrode shape> The shapes of the first electrode and the second electrode can be flat, wire-like, needle-like, etc., as long as they do not impede the effects of the present disclosure. Preferably, the shape of the first electrode is flat. Also, preferably, the shape of the second electrode is flat.

[0051] 7A to 7C are schematic diagrams showing non-limiting examples of electrode shapes. The edge of the first electrode and the edge of the second electrode are preferably linear or approximately linear. Approximately linear does not have to be an exact straight line, and may be linear to the extent that the discharge is uniform and electric field concentration can be suppressed, with some unevenness being acceptable. Specifically, as shown in FIG. 7A, a linear shape without unevenness is preferable. By having linear edges of the electrodes, the discharge is uniform and charge can be supplied uniformly along the longitudinal direction. Since the induced current is also supplied to the surface of the photosensitive drum, if the discharge is uniform in the longitudinal direction, the surface potential on the photosensitive drum is also uniform, making it easier to suppress streaky images. In addition, the non-uniformity in the longitudinal direction of the induced current supplied to the dirt is reduced, and the effects of discharging and dispersing the dirt are also uniform.

[0052] Considering the above reasons, when a convex portion exists at the edge, the electric field is concentrated at the convex portion, forming a place where the discharge is stronger than the surroundings. In order to suppress the electric field concentration, the maximum height of the convex portion at the edge portion of the first electrode and the edge portion of the second electrode (preferably the edge portion of the first electrode) is preferably 0 to 40 μm and the width is preferably 0 to 40 μm. The height is more preferably 0 to 25 μm and the width is more preferably 0 to 25 μm. The height of the convex portion can also be referred to as the length in the length A direction. The width of the convex portion can also be referred to as the length in the direction perpendicular to the length A direction and along the dielectric surface. The shape of the convex portion is not limited to the sawtooth shape as shown in FIG. 7A and FIG. 7B. The convex portion also includes those that are regularly present at the edge portion as shown in FIG. 7B and those that have at least one convex portion at the edge portion as shown in FIG. 7C.

[0053] In order to reduce the maximum height and width of the convex portion to the above range, for example, when forming the electrode while masking it with a liquid such as screen printing or metal vapor deposition, a method of printing using a masking member whose edge shape is polished or cut with a sharp blade so that there are no projections or recesses in the longitudinal direction of the dielectric surface on which the electrode is formed can be mentioned. Also, a metal sheet whose edge shape is polished or cut with a sharp blade so that there are no projections or recesses in the longitudinal direction, a razor, or the like can be used.

[0054] As described above, the electric field concentration caused by the convex part at the edge of the first electrode can be reduced by controlling the overlap amount between the first and second electrodes. At the same time, the electric field concentration on the convex part can be suppressed, which can suppress the dielectric breakdown between the two electrodes, making it easier to obtain a more stable discharge within the above-mentioned range of overlap amount.

[0055] Methods for forming the electrodes include pasting or vapor deposition of a metal plate or metal foil, screen printing, etc. In order to generate a stable discharge and supply a charge uniformly along the length of the body to be charged, it is preferable to use a conductive tape or metal foil with a regular edge shape, or a metal plate with a polished tip like a razor as the electrode.

[0056] The shape of the electrodes can be measured by observing and verifying the plasma actuator from the first electrode side with an optical microscope, laser microscope, electron microscope, digital camera, visual inspection, a magnifying glass, etc. To measure the shape more accurately, it is preferable to use a laser microscope or optical microscope with a dimensional measurement function. Specifically, the height and width of the protrusions on the edge of the first electrode and the edge of the second electrode can be calculated by the following procedure.

[0057] The height and width of the convex portion can be obtained, for example, as follows. First, the step formed by the first electrode and the dielectric layer is photographed using an optical microscope, a laser microscope, a confocal microscope, or the like. Specifically, a laser microscope (product name: Color 3D Laser Microscope VK-8700, manufactured by Keyence Corporation) is used to observe and confirm the step in the longitudinal direction in a field of view of 1000 μm vertical and 1000 μm horizontal. Two-dimensional image data is obtained by scanning the laser on the XY plane within the field of view, and three-dimensional image data is obtained by repeating the scan every 0.2 μm in the height direction in the Z direction. The three-dimensional data is acquired over the entire longitudinal area of ​​the first electrode, and the height and width as shown in Fig. 7B can be calculated for the obtained three-dimensional image group using the length measurement function of the analysis software attached to the laser microscope. Note that, since the height of a protrusion is more sensitive to the electric field intensity than its width, the one with the greatest height among the measured protrusions was taken as the maximum protrusion.

[0058] <Applied voltage> The AC voltage applied between the first electrode 203 and the second electrode 205 of the plasma actuator is not particularly limited as long as it can generate plasma in the plasma actuator. In a preferred embodiment, the AC voltage or pulse voltage is used. Furthermore, the amplitude of the voltage is preferably 1 kV to 100 kV, more preferably 1 kV to 10 kV. Furthermore, the frequency of the voltage is preferably 1 kHz or higher, more preferably 5 kHz to 20 kHz.

[0059] When the voltage is an AC voltage, the waveform of the AC voltage is not particularly limited, and a sine wave, a square wave, a triangular wave, or the like can be adopted, but a square wave is preferable from the viewpoint of the speed of the voltage rise. The duty ratio of the voltage can also be appropriately selected, but a fast voltage rise is preferable. The voltage is preferably applied so that the voltage rise from the bottom to the peak of the wavelength amplitude is 4,000,000 V / sec or more. Note that the value (voltage / film thickness) obtained by dividing the amplitude of the voltage applied between the first electrode 203 and the second electrode 205 by the film thickness of the dielectric 201 is preferably 10 kV / mm or more.

[0060] <DC voltage> By superimposing the DC voltage, it is possible to supply an induced flow having a charge polarity biased toward a component of the opposite polarity to the charge polarity of the dirt. That is, it is preferable that the electrophotographic image forming apparatus applies a DC voltage between the first electrode of the plasma actuator and the electrophotographic photosensitive member. This preferably charges the surface of the electrophotographic photosensitive member and the transfer residual toner to the same polarity. The DC voltage applied between the first electrode 203 of the plasma actuator and the photosensitive drum 104 is not particularly limited as long as it is possible to preferentially supply charges of the same polarity as the DC voltage among the charges contained in the induced current 106 to the photosensitive drum surface 104-1. The DC voltage can be appropriately set to adjust the charge amount of the photosensitive drum 104 and the dirt 105 remaining on the photosensitive drum surface. From the viewpoint of controlling the charge amount of the photosensitive drum and the dirt, the DC voltage is preferably 200V to 1500V or -200V to -1500V. More preferably, it is 400V to 1000V or -400V to -1000V.

[0061] In addition, the higher the applied DC voltage, the stronger the electric field formed between the first electrode and the photosensitive drum, so that more charges are supplied to the photosensitive drum surface. This improves the charging performance for the photosensitive drum and dirt remaining on the photosensitive drum surface. In addition, the DC voltage increases the flow rate of the induced flow, improving the effect of scattering dirt.

[0062] By superimposing a DC voltage, the plasma actuator can also be used as a charging device. That is, the charging device includes at least a plasma actuator and an electrophotographic photosensitive member. Then, a DC voltage is superimposed between a first electrode of the plasma actuator and the electrophotographic photosensitive member. Since such a charging device can also be used as a charging device for an electrophotographic photosensitive member in an electrophotographic process, a charging device such as a contact-type charging roller can be omitted.

[0063] <Dielectric> The dielectric is not particularly limited as long as it is a material having high electrical insulation properties. For example, resins such as polyurethane resin, polyimide, polyester, fluororesin, silicone resin, acrylic resin, and phenol resin, glass, ceramics, and composite materials in which these are mixed with resins, etc. can be used. The dielectric is preferably silicone resin, polyimide, or glass. For example, a material such as silicone resin that has a high volume resistivity, a chemical structure with few uneven biases and crystal grain boundaries, a small charge bias, and a low dielectric constant is used. This is more preferable because it makes it possible to suppress dielectric breakdown between the first electrode and the second electrode.

[0064] In addition, it is also a preferred embodiment that the dielectric is a polyurethane resin. For example, the plasma actuator is embedded in a cleaning blade that includes an elastic member and a support member that supports the elastic member. The plasma actuator is provided so that polyurethane resin can be used as the dielectric by using polyurethane resin for the elastic member. For example, the second electrode may be embedded in the elastic member, and a first electrode may be provided on the outside of the elastic member so that an induced flow can be generated in a desired direction. For example, as shown in FIG. 12, a first electrode 203 may be provided on the outside of an elastic member as the cleaning member 103, and the edge of the first electrode in a direction other than the direction in which the induced flow 106 is generated may be covered with a dielectric 209. Then, an embodiment may be provided in which the sheet metal of the cleaning member 103 is used as the second electrode 205 of the plasma actuator.

[0065] Furthermore, the shorter the shortest distance between the first electrode and the second electrode in the plasma actuator 102, the easier it is to generate plasma. Therefore, the thinner the film thickness of the dielectric is, as long as it does not cause electrical breakdown, and can be 10 μm to 1000 μm, and more preferably 10 μm to 200 μm.

[0066] <Layout of plasma actuator and cleaning member> The plasma actuator supplies an induced flow to the dirt (transfer residual toner) before the dirt (transfer residual toner) enters the contact portion between the cleaning member and the electrophotographic photosensitive member. For example, it is sufficient if an induced flow can be supplied between the fixing member and the cleaning member in the electrophotographic photosensitive member. In order to improve the cleaning performance of the cleaning member, it is preferable to arrange the supply position of the induced flow by the plasma actuator on the upstream side, as close as possible to the cleaning member, with respect to the contact portion of the cleaning member with the photosensitive drum surface. In other words, the plasma actuator supplies an induced flow upstream in the rotation direction of the electrophotographic photosensitive member from the contact portion between the cleaning member and the electrophotographic photosensitive member (FIG. 1B, etc.).

[0067] It is preferable that the plasma actuator is attached to the upstream surface of the cleaning member with respect to the rotation direction of the photosensitive drum surface, or that the plasma actuator is attached to the process cartridge or the main body and installed immediately upstream of the cleaning member. It is preferable that the cleaning member is an electrophotographic cleaning blade, and that the plasma actuator is provided on the upstream side of the electrophotographic cleaning blade with respect to the rotation direction of the photosensitive drum surface (FIGS. 1B and 8A). The cleaning performance can be improved by arranging the cleaning device so that the dirt is cleaned before the electric charge received by the dirt is gradually changed by the induced flow and immediately after the dirt is physically scattered.

[0068] The plasma actuator may be provided downstream of the cleaning member in the rotation direction of the photosensitive drum surface (FIGS. 8B and 8C). In such an embodiment, even if dirt electrostatically adhered to the surface of the photosensitive drum slips through the contact portion between the cleaning member and the photosensitive drum, the dirt can be discharged by irradiating the dirt with an induced flow, and the electrostatic adhesion of the dirt to the surface of the photosensitive drum can be weakened. As a result, when the dirt enters the contact portion between the cleaning member and the photosensitive drum during the next rotation of the photosensitive drum, the dirt can be removed by the cleaning member.

[0069] <Plasma actuator (PA) and photoconductor arrangement (orientation, arrangement relative to substrate)> The plasma actuator 102, which generates an induced flow containing electric charge, is positioned so that the induced flow 106 containing electric charge is supplied directly to the photosensitive drum surface 104-1 in order to increase the charging efficiency of the surface area of ​​the photosensitive drum, which is the charged body. For example, the plasma actuator and the body to be charged may be arranged so that the induced flow 106 carrying the charge is supplied to the surface of the photosensitive drum over the shortest distance.

[0070] Also, for example, it is preferable to arrange the plasma actuator so that the surface 104-1 of the photosensitive drum is included on an extension line extending from the edge of the first electrode of the plasma actuator along the exposed portion 201-1 of the first surface of the dielectric. It is also preferable to arrange the plasma actuator so that a point 701b, which will be described later, exists. The plasma actuator is preferably arranged so that the surface of the photosensitive drum, which is the body to be charged, is included on the extension line of the blowing direction of the induced flow, as shown in Fig. 8A. It is more preferable to arrange the plasma actuator so that the direction of the first electrode from the dielectric body is opposite to the direction from the dielectric body to the surface of the photosensitive drum, which is the body to be charged.

[0071] <Distance between plasma actuator and photosensitive drum> The distance between the plasma actuator and the photosensitive drum may be set appropriately according to the output of the plasma actuator, etc., as long as it is a distance that can charge and discharge dirt. In order to more effectively supply the charge in the induced flow to the surface of the photosensitive drum, it is preferable to shorten the distance between the plasma actuator and the photosensitive drum within a range in which the discharge does not reach the photosensitive drum directly from the first electrode of the plasma actuator. As an example, in FIG. 8A, it is preferable to arrange the distance 701 between the tip 701a on the second electrode side of the plasma actuator 102 and the point 701b where the extension line (line 700) extending from the edge of the first electrode of the plasma actuator in the direction along the exposed portion 201-1 of the first surface of the dielectric intersects with the photosensitive drum surface, so that it is 1 mm to 20 mm (more preferably 1 mm to 10 mm, and even more preferably 1 mm to 5 mm).

[0072] <Orientation of plasma actuator relative to photosensitive drum rotation direction> In the electrophotographic apparatus 101, the outflow direction of the induced flow 106 of the plasma actuator 102 is not particularly limited as long as it faces the photosensitive drum 104, but a preferable configuration for achieving the effects of the present disclosure is shown below.

[0073] 8A, an extension line 700 extending from the edge of the first electrode of the plasma actuator along the exposed portion 201-1 of the first surface of the dielectric intersects with the surface of the photosensitive drum at point 701b. A velocity vector in the rotational direction of the photosensitive drum on the tangent to the surface of the photosensitive drum at point 701b is defined as a tangent vector 702. When the outflow direction vector 106a of the induced flow 106 supplied from the plasma actuator 102 is decomposed, it is preferable that the outflow direction vector 106a has a directional component 106x that is parallel to and opposite to the tangent vector 702 (hereinafter, an arrangement in which the directional component 106x is opposite to the tangent vector 702 will be referred to as counter, and an arrangement in which it is parallel to the same direction will be referred to as with). When the induced flow flows in the above-mentioned direction, the relative speed of the induced flow to the photosensitive drum becomes faster, and a stronger wind can be blown onto the dirt remaining on the photosensitive drum surface. As a result, the dirt can be rolled on the photosensitive drum surface, and the photosensitive drum and the dirt can be more effectively de-electrified and charged.

[0074] Also, when the outflow direction vector 106a is decomposed, the outflow direction vector 106a may have a directional component parallel to and in the same direction as the tangent vector 702 (the With described above). In such a case, the induced flow is less likely to be disturbed by the rotation of the photosensitive drum, and the photosensitive drum surface and dirt can be in contact with the induced flow for a longer period of time. As a result, the photosensitive drum and dirt can be more effectively neutralized and charged.

[0075] <Angle> Residual toner, the main component of dirt, is nearly spherical, and it has been discovered that there is an appropriate angle for more effectively supplying an induced flow to the gap between the photosensitive drum surface and the dirt. By supplying an induced flow to the gap, the dirt on the photosensitive drum surface rolls, making it easier to charge and de-electrify the entire surface of the dirt. In addition, the photosensitive drum surface covered with dirt can also be more easily charged and de-electrified. It becomes easier. That is, the narrow angle θ is defined as the narrow angle that an extension line extending from the edge of the first electrode of the plasma actuator in a direction along exposed portion 201-1 of the first surface of the dielectric makes with respect to tangent vector 702. The narrow angle θ is preferably 0° to 90°, and more preferably 10° to 45°.

[0076] <Cleaning materials> The cleaning member is a member that comes into contact with the surface of the photosensitive drum to remove toner remaining on the photosensitive drum after the transfer process. The cleaning member may be any known member used in electrophotographic devices, and is not particularly limited, but is preferably a brush, a cleaning blade, or a resin sheet.

[0077] Among them, a cleaning blade made of an elastic resin is preferred, which has a high smoothness at the tip end of the contact portion and can suppress the passing of toner and other contaminants even when contacted with a light pressure. That is, the cleaning member is preferably an electrophotographic cleaning blade that has an elastic member and a support member that supports the elastic member and cleans the surface of an electrophotographic photoreceptor.

[0078] Examples of the elastic member include the following materials: polyurethane elastomer, ethylene-propylene-diene copolymer rubber (EPDM), acrylonitrile-butadiene rubber (NBR), chloroprene rubber (CR), natural rubber (NR), isoprene rubber (IR), styrene-butadiene rubber (SBR), fluororubber, silicone rubber, epichlorohydrin rubber, NBR hydride, polysulfide rubber, etc. Polyurethane elastomer is preferred. As the polyurethane elastomer, polyester urethane elastomer, which has excellent wear resistance and viscoelastic properties, is preferred.

[0079] Furthermore, the dielectric of the plasma actuator can be made of the cleaning material, and the second electrode can be embedded in the cleaning material. This configuration makes it possible to further integrate the cleaning material and the plasma actuator, making it possible to miniaturize the device. Furthermore, since the surface of the photosensitive drum can be charged by the plasma actuator, the plasma actuator can also be used as a charging member.

[0080] <Process cartridge> 9 is a schematic cross-sectional view of an electrophotographic process cartridge equipped with a plasma actuator and a cleaning member. For example, the process cartridge is detachably mountable to an electrophotographic image forming apparatus and includes an electrophotographic photosensitive member 104, a cleaning member 103 in contact with the surface of the electrophotographic photosensitive member, and a plasma actuator 102. The process cartridge may further include a developing device and a charging device. The developing device is an integrated device of at least the developing roller 53 and the toner container 56, and may include a toner supply roller 54, a toner 59, a developing blade 58, and an agitating blade 510 as necessary. The charging device may be a known device having a charging roller (not shown), for example.

[0081] Alternatively, the process cartridge may be one in which the developing device and the charging device are integrated and configured to be detachably attached to the main body of the electrophotographic device. In this case, the charging device may be one in which at least the photosensitive drum 104 and the plasma actuator 102 are integrated. The charging device may include a cleaning blade 103 and a waste toner container 57.

[0082] <Electrophotographic device> FIG. 10 is a schematic diagram of an electrophotographic apparatus using a plasma actuator and a cleaning member. This electrophotographic apparatus is composed of an electrophotographic photosensitive member, a charging device for charging the electrophotographic photosensitive member, a latent image forming device for forming an electrostatic latent image by exposing the electrophotographic photosensitive member to light, a developing device for developing the electrostatic latent image as a toner image, a transfer device having a transfer member 64 for transferring the toner image to a transfer material, a cleaning device having a cleaning member for recovering the residual toner on the electrophotographic photosensitive member, and a fixing device for fixing the toner image to the transfer material. For example, as shown in Fig. 10, a plasma actuator 102 is provided on a cleaning member 103. The plasma actuator and the cleaning member can also be used as a charging device for this electrophotographic apparatus.

[0083] The electrophotographic photoreceptor 104 is a rotating drum type having a photosensitive layer on a conductive substrate. The electrophotographic photoreceptor 104 is rotated in the direction of the arrow at a predetermined peripheral speed (process speed). The charging device has a contact-type charging roller 69 arranged in contact with the electrophotographic photoreceptor 104 as a charging member. The charging member charges the electrophotographic photoreceptor 104 to a predetermined potential by applying a predetermined DC voltage from a charging power source. An exposure device such as a laser beam scanner is used as a latent image forming device (not shown) that forms an electrostatic latent image on the electrophotographic photoreceptor 104. An electrostatic latent image is formed by supplying exposure light 67 corresponding to image information to the uniformly charged electrophotographic photoreceptor 104.

[0084] The developing device has a developing sleeve or developing roller 63 arranged in close proximity to or in contact with the electrophotographic photoreceptor 104. The developing device develops the electrostatic latent image by reversal development with toner electrostatically treated to have the same polarity as the charged polarity of the electrophotographic photoreceptor 104 to form a toner image. The transfer device has a contact-type transfer member (transfer roller) 64. The toner image is transferred from the electrophotographic photoreceptor 104 to a transfer material such as plain paper. The transfer material is transported by a paper feed system having a transport member. In the electrophotographic device of FIG. 10, the transfer material is, for example, paper, but if the electrophotographic device is equipped with an intermediate transfer member, the transfer material may be the intermediate transfer member.

[0085] The cleaning device has a cleaning blade 103 and a collection container (not shown), and mechanically scrapes off and collects the residual toner remaining on the electrophotographic photosensitive member 104 after the developed toner image is transferred to the transfer material. A plasma actuator is preferably disposed upstream of the cleaning device in the rotation direction of the photosensitive drum. In FIG. 10, a plasma actuator 102 is provided on the cleaning blade 103, and an induced flow can be supplied to the residual toner before the residual toner enters the cleaning blade 103. The toner image transferred to the transfer material is fixed to the transfer material by passing between a fixing belt 65 heated by a heating device (not shown) and a roller disposed opposite the fixing belt. The electrophotographic photoconductor 104 as the member to be charged is not particularly limited, and any known photoconductor used in electrophotographic devices can be used. The toner is also not particularly limited, and any known toner can be used. EXAMPLES

[0086] The present disclosure will be described in further detail below using examples and comparative examples, but the aspects of the present disclosure are not limited thereto.

[0087] <Example 1> 1. Fabrication of Plasma Actuator A piece of aluminum foil measuring 2.5 mm in length, 300 mm in width and 100 μm in thickness was cut with a sharp razor onto a first surface of silicone resin (5 mm in length, 300 mm in width and 150 μm in thickness) as a dielectric, and attached with adhesive tape to form a first electrode. A piece of aluminum foil measuring 2 mm in length, 300 mm in width and 100 μm in thickness was also attached with adhesive tape to a second surface of the silicone resin, diagonally opposite the aluminum foil attached to the first surface, to form a second electrode. Furthermore, the second surface including the second electrode was covered with polyimide tape. Thus, A plasma actuator was fabricated in which the first electrode and the second electrode were arranged to overlap over a width of 500 μm with a dielectric (silicone resin) sandwiched between them. Lead wires were attached to the first electrode and the second electrode so that a voltage could be applied. The convex portion of the edge of the first electrode was measured over the entire length direction using a laser microscope. The largest protrusion had a height of 21 μm and a width of 23 μm.

[0088] 2. Characterization [Induced flow velocity] Next, the speed of the induced flow generated by the plasma actuator was calculated using particle image velocimetry (PIV). Figure 11 shows a schematic diagram of the PIV measurement. PIV measurement is a technique in which oil mist injected from the upstream of a wind tunnel is visualized using a PIV Laser (Kato Koken Co., Ltd., G450, 450mW) 1201 installed downstream of the measurement section, and then photographed using a USB high-speed camera (Kato Koken Co., Ltd., k4) 1202 installed above the measurement section.

[0089] In the oil mist, a square wave with an amplitude of 4 kVpp and a frequency of 10 kHz was applied between the first and second electrodes of the fabricated plasma actuator 102, and a DC voltage of -800 V was applied between the first electrode and the ground electrode of the electrophotographic device to generate an induced flow 106. The above-mentioned photographing was performed in this state. The laser output was 450 mW, the camera exposure F2.8, and the shutter speed = 1 / 800; FPS = 800. The photographed image was analyzed in PIV analysis software (Flow-Expert64 ver1.3.3) to analyze the speed of the oil mist per unit time, and the flow velocity distribution of the induced flow was obtained.

[0090] Specifically, the induced flow velocity was determined as the average flow velocity of the components parallel to the outflow direction vector 106a of the induced flow 106 among the velocity vectors measured within a range of 0.2 mm x 1.0 mm in an area 1.0 mm away from the tip position of the plasma actuator. In Example 1, the induced flow velocity was 0.29 m / sec.

[0091] <Image evaluation> To confirm the discharge uniformity of the plasma actuator, the following evaluations were carried out. First, an electrophotographic laser printer (product name: HP LaserJet Enterprise Color M555dn, manufactured by Hewlett-Packard) was prepared as an electrophotographic device and modified so that a specified voltage could be applied. A conductor is connected to the first and second electrodes of the plasma actuator, and a voltage is applied to generate an induced flow. Specifically, an AC voltage is applied between the first and second electrodes from an AC power source, and a DC voltage is applied between the first electrode and the ground electrode of the electrophotographic device. Modifications have been made to make this possible. A plasma actuator was attached to the cleaning blade of the process cartridge. Specifically, the polyimide tape covering the second electrode 205 of the plasma actuator 102 was glued and fixed. As shown in FIG. 10, a cleaning blade 103 provided with a plasma actuator 102 was disposed on the upstream side of the charging member 69 in the photoconductor rotation direction. Furthermore, the penetration depth of the cleaning blade was reduced by 50%, the distance between the tip of the plasma actuator and the surface of the photosensitive drum (701 in Figure 8A) was set to 2 mm, and the narrow angle θ (Figure 8A), which is the angle between the extension line along the exposed portion 201-1 of the first surface of the dielectric 201 and the tangent vector 702, was set to 30°.

[0092] Next, in order to acclimate the electrophotographic apparatus and the process cartridge to the evaluation environment, the apparatus was left in an environment of 18° C. / 30% RH for 48 hours. After that, a halftone image (photosensitive An image was output in which horizontal lines of 1 dot width and 2 dot intervals were drawn in the direction perpendicular to the direction of rotation of the main drum. This halftone was visually observed, and vertical streaks were evaluated according to the following criteria. In this example, it was ranked A.

[0093] [Evaluation of vertical lines in halftone images (initial image line evaluation)] Rank A: No vertical streaks are visible on the halftone image even when observed under a microscope. Rank B: No vertical streaks are visible on the halftone image when observed with the naked eye, but they are visible when observed under a microscope. Rank C: Vertical stripes are visible on some parts of the halftone image. Rank D: Vertical stripes are visible across the entire surface of the halftone image.

[0094] [Static electricity removal performance of dirt] The static electricity removal performance of the plasma actuator 1 against dirt was measured. The static electricity removing performance of the plasma actuator against dirt (residual toner) was evaluated by measuring the charge of the residual toner before and after it was hit by the induced flow from the plasma actuator using a charge distribution measuring device according to the following method.

[0095] Specifically, the amount of transfer residual toner was increased by increasing the transfer current using the electrophotographic laser printer equipped with the plasma actuator. Then, the charge distribution of the transfer residual toner was measured after the toner passed through the plasma actuator driven under the same conditions as in the measurement of the induced flow velocity. The number ratio X1 of the transfer residual toner charged to the same polarity as the voltage applied to the transfer member was measured. After that, without driving the plasma actuator, the charge distribution of the transfer residual toner after it passed through the plasma actuator was measured, and the number ratio X2 of the transfer residual toner charged with the same polarity as the voltage applied to the transfer member was measured. Note that when carrying out this measurement, since it was necessary to measure the change in charge distribution due to irradiation by the plasma actuator, the tip of the cleaning member was cut off while maintaining the arrangement of the cleaning member and the plasma actuator, and the measurement was carried out so that all of the transfer residual toner passed through the cleaning member.

[0096] The amount of the transfer residual toner when checking the change in the charge polarity of the transfer residual toner was controlled by adjusting the transfer bias so that the fog value obtained by the following measurement method was 5%. The fog value was specifically measured as follows. First, the printing operation was stopped while printing a solid black image, and the transfer residual toner adhering between the transfer member abutment part and the charging member abutment part on the photosensitive drum surface was peeled off with a tape (product name: CT18, manufactured by Nichiban Co., Ltd.). Next, the reflectance was measured with a reflection densitometer (product name: TC-6DS / A, manufactured by Tokyo Denshoku Co., Ltd.), and the reduction amount (%) of the reflectance based on the reflectance of the tape was measured and used as the fog value.

[0097] The measurement is performed using an E-spart analyzer (manufactured by Hosokawa Micron Corporation). The E-spart analyzer is a device that introduces sample particles into a detection section (measurement section) that simultaneously forms an electric field and an acoustic field, and measures the particle size and charge by measuring the particle movement speed using the laser Doppler method. The air flow rate for aspirating the sample particles was 400 L / min, the voltage applied to the measurement electrode was 100 V, and the count number was 300 particles.

[0098] Then, the proportion of transfer residual toner charged with the same polarity as the polarity (polarity A) applied to the transfer member when the plasma actuator is driven is defined as X1, and the proportion of transfer residual toner charged with the same polarity as polarity A when the plasma actuator is not driven is defined as X2, and the rate of change in the proportion Δ(Δ=((X2-X1) / X2)×100) was calculated. In the embodiment, the ratio X of the number of positively charged residual toner particles was calculated from the charge amount distribution of the residual toner particles obtained by the measurement. The ratio of positively charged residual toner when the plasma actuator was not driven was taken as X1, and the ratio of positively charged residual toner when the plasma actuator was not driven was taken as X2, and the rate of change in ratio Δ (Δ=((X2-X1) / X2)×100) was calculated. The evaluation results are shown in Table 2.

[0099] The number-average particle size of the toner can also be measured using a precision particle size distribution measuring device using the narrow hole electrical resistance method, such as the "Coulter Counter Multisizer 3" (registered trademark product name, manufactured by Beckman Coulter, Inc.), equipped with a 100 μm aperture tube. The measurement conditions can be set and the measurement data can be analyzed using the accompanying dedicated software, "Beckman Coulter Multisizer 3 Version 3.51" (manufactured by Beckman Coulter, Inc.).

[0100] <Evaluation of streak images and stain resistance after durability> After evaluating the vertical streaks in the initial image, a total of 100,000 sheets of images were output continuously under the same conditions. The output image was an alphabet letter "E" of 4 points on A4 size paper with a print rate of 1.0%. After that, a halftone image (an image in which horizontal lines of 1 dot width and 2 dot intervals are drawn in the direction perpendicular to the rotation direction of the photosensitive drum) was output. This halftone was visually observed and evaluated under the same criteria as those for the vertical streaks in the initial image. In Example 1, it was ranked A.

[0101] <Dirt adhesion in grooves> Among the vertical streaks that occurred in the test to evaluate the stain resistance performance, the discharge part of the charged member corresponding to the vertical streak part with the largest density difference from the surroundings was photographed using a laser microscope (product name: Color 3D Laser Microscope VK-8700 manufactured by Keyence Corporation), and the number of stains (toner) attached was counted. Observation was performed in a field of view of 1000 μm vertically and 1000 μm horizontally, and the number of toner particles attached was counted. Since no clear streaks were observed in this example, the number of attached stains was counted at the places where the attachment of stains was observed on the surface of the charged member in the longitudinal direction. The number of attached stains was 10.

[0102] [Dielectric breakdown evaluation] After carrying out the durability evaluation, the first electrode of the plasma actuator 102 was visually observed to confirm whether there were any locations where dielectric breakdown had occurred between the two electrodes, and the number of such locations was counted. Specifically, if "burnt" due to dielectric breakdown was confirmed at the interface between the first electrode and the dielectric, or at the interface between the second electrode and the dielectric, it was determined that dielectric breakdown had occurred. In Example 1, no dielectric breakdown occurred.

[0103] <Example 2> A process cartridge similar to that in Example 1 was prepared and evaluated, except that the cleaning member was changed to a resin sheet (ABS resin sheet, width 300 mm, length 20 mm, thickness 1 mm). The evaluation results are shown in Table 2.

[0104] <Example 3> The cleaning member is a brush (width 300 mm, the length of the part that contacts the photosensitive drum surface is 280 mm, the width in the running direction of the photosensitive drum surface is 4 mm, the brush hairs are 15 mm long, 30 μm thick, made of nylon or rayon resin, density 250,000 pieces / inch 2 A process cartridge similar to that in Example 1 was prepared and evaluated, except that the load was changed to 300 gf (average contact load in the longitudinal direction: 300 gf). The evaluation results are shown in Table 2.

[0105] <Example 4> Instead of attaching the plasma actuator to the cleaning material, an ABS sheet is attached to the cartridge frame so that the plasma actuator can be positioned as shown below. Specifically, as shown in FIG. 1A, the induced flow is irradiated at a position 5 mm upstream of the cleaning blade in the rotation direction of the photosensitive drum. A process cartridge was produced and evaluated in the same manner as in Example 1, except that the plasma actuator was installed so as to have the other arrangements shown in Table 1. The evaluation results are shown in Table 2.

[0106] <Examples 5 to 25> A process cartridge was produced and evaluated in the same manner as in Example 1, except that the overlap amount of the electrodes of the plasma actuator, the height and width of the maximum convex part, the DC voltage, the arrangement angle, and the material of the dielectric were changed as shown in Table 1. The evaluation results are shown in Table 2. In Example 25, a polyimide resin sheet was used as the dielectric. In Examples 9 to 12, the cut aluminum foil was ground with sandpaper to form an uneven shape and convex portions on the edge of the first electrode where discharge occurs.

[0107] <Example 26> As shown in Fig. 12, the second electrode 205 of the plasma actuator was configured as a metal plate that is a support member for a cleaning blade, and further, an insulating ABS sheet 209 was attached onto the first electrode so that an induced flow would not occur on the metal plate side. Except for this, a process cartridge was produced and evaluated in the same manner as in Example 1. The evaluation results are shown in Table 2.

[0108] <Example 27> A process cartridge was produced and evaluated in the same manner as in Example 1, except that the charging member of the process cartridge was removed and the plasma actuator was used as the charging member. The evaluation results are shown in Table 2.

[0109] <Example 28> A process cartridge was produced and evaluated in the same manner as in Example 1, except that the first and second electrodes of the plasma actuator were not overlapped and were spaced apart by 200 μm. The evaluation results are shown in Table 2. In this example, the two electrodes did not overlap, so the induced flow by the plasma actuator was weak, and the effect of discharging and / or charging the residual toner after transfer was relatively weak compared to Example 1. It is believed that this is the reason why streaked images occurred after durability testing. The evaluation results are shown in Table 2.

[0110] <Comparative Example 1> A process cartridge was produced and evaluated in the same manner as in Example 1, except that the plasma actuator was not used. The evaluation results are shown in Table 2. In this comparative example, the plasma actuator did not have the effect of removing static electricity from dirt or dispersing the dirt, so the dirt slipped through the contact area of ​​the cleaning blade, resulting in streaky dirt on the charging member. The evaluation results are shown in Table 2.

[0111] <Comparative Example 2> A conductive portion was provided on the cleaning blade, and the cleaning blade was modified so that it was charged by the conductive portion, and the charging member was removed, and the cleaning blade was evaluated in the same manner as in Example 1. Specifically, the surface of the cleaning blade facing the photosensitive drum was subjected to metal deposition to form a conductive surface, and then a conductor was formed on the conductive surface, and the blade was modified so that a DC voltage (-1000V) could be applied. This produced a configuration that performed cleaning and charging simultaneously. The evaluation results are shown in Table 2. In this comparative example, since the plasma actuator did not have the effect of discharging and dispersing dirt, the dirt slipped through the contact area of ​​the cleaning blade, resulting in streaky dirt on the charging member. The evaluation results are shown in Table 2.

[0112] <Comparative Example 3> As shown in FIG. 13, the plane of the upper section of the first electrode is perpendicular to the diameter direction of the photosensitive drum. A process cartridge was produced and evaluated in the same manner as in Example 1, except that the plasma actuator was arranged so that the angle of the cleaning blade did not change. The plasma actuator was provided on an ABS substrate separately from the cleaning blade, and the angle of the cleaning blade did not change. The evaluation results are shown in Table 2. In this comparative example, the induced flow of the plasma actuator was not directly supplied to the surface of the photosensitive drum. It is believed that this was the reason why the effect of removing electricity and / or charging the residual toner after transfer was not obtained. The evaluation results are shown in Table 2.

[0113] [Table 1] In Examples 19 to 23, the narrow angle θ was changed, but the attachment angle of the plasma actuator was adjusted using an ABS base material so that the angle at which the cleaning blade contacted the surface did not change. In the table, "upstream" in "location" indicates that the plasma actuator is located upstream of the cleaning member in the rotation direction of the photosensitive drum (FIGS. 8A and 8D), while "downstream" indicates that the plasma actuator is located downstream of the cleaning member in the rotation direction of the photosensitive drum (FIGS. 8B and 8C).

[0114] [Table 2]

[0115] The present disclosure relates to the following configurations. (Configuration 1) An electrophotographic image forming apparatus comprising: an electrophotographic photosensitive member as a member to be charged; a cleaning member in contact with a surface of the electrophotographic photosensitive member; and a plasma actuator, The plasma actuator comprises: A dielectric material; a first electrode provided on a first surface of the dielectric; a second electrode provided on the first electrode with the dielectric interposed therebetween; By applying an AC voltage between the first electrode and the second electrode, the plasma actuator generates an induced flow from an edge of the first electrode along an exposed portion of the first surface of the dielectric material that is not covered by the first electrode; the plasma actuator is disposed so as to be capable of directly supplying the induced flow to the surface of the electrophotographic photosensitive member, and controls the potential of transfer residual toner on the surface of the electrophotographic photosensitive member. (Configuration 2) Controlling the potential of the transfer residual toner removing static electricity from the transfer residual toner by the induced flow; and a charge of the transfer residual toner by the induced flow to the same polarity as the polarity of the surface of the electrophotographic photosensitive member, (Configuration 3) 3. The electrophotographic image forming apparatus according to claim 1, wherein the control of the potential of the transfer residual toner is performed before the transfer residual toner enters a contact portion between the cleaning member and the electrophotographic photosensitive member. (Configuration 4) 4. The electrophotographic image forming apparatus according to any one of Configurations 1 to 3, wherein the cleaning member is an electrophotographic cleaning blade having an elastic member and a support member that supports the elastic member, and that cleans the surface of the electrophotographic photoreceptor. (Configuration 5) 5. The electrophotographic image forming apparatus according to any one of Configurations 1 to 4, wherein the plasma actuator is disposed on a surface of the cleaning member. (Configuration 6) When the plasma actuator is seen through from the front surface side of the first electrode, At least a portion of the edge of the first electrode overlaps with the second electrode; 6. The electrophotographic image forming apparatus according to any one of Configurations 1 to 5, wherein a length A between the edge of the first electrode and the edge of the second electrode forming the overlapping portion is 0 to 1000 μm. (Configuration 7) 7. The electrophotographic image forming apparatus according to any one of Configurations 1 to 6, wherein the first electrode and the second electrode are arranged diagonally opposite each other with the dielectric material therebetween. (Configuration 8) 8. The electrophotographic image forming apparatus according to any one of Configurations 1 to 7, wherein the height of the maximum convex portion at the edge of the first electrode is 0 to 40 μm and the width is 0 to 40 μm. (Configuration 9) The electrophotographic image forming apparatus according to any one of Configurations 1 to 8, wherein the plasma actuator directly supplies the induced flow upstream in the rotation direction of the electrophotographic photosensitive member relative to a contact portion between the cleaning member and the electrophotographic photosensitive member. (Configuration 10) a point where an extension line extending from the edge of the first electrode in a direction along the exposed portion of the first surface of the dielectric intersects with the surface of the electrophotographic photosensitive member, and a velocity vector in a rotational direction of the electrophotographic photosensitive member on a tangent to the surface of the electrophotographic photosensitive member at the point is defined as a tangent vector; 10. The electrophotographic image forming apparatus according to any one of configurations 1 to 9, wherein when an outflow direction vector of the induced flow supplied from the plasma actuator is decomposed, the outflow direction vector has a directional component that is parallel to and points in the same direction as the tangent vector. (Configuration 11) a point where an extension line extending from the edge of the first electrode in a direction along the exposed portion of the first surface of the dielectric intersects with the surface of the electrophotographic photosensitive member, and a velocity vector in a rotational direction of the electrophotographic photosensitive member on a tangent to the surface of the electrophotographic photosensitive member at the point is defined as a tangent vector; 10. The electrophotographic image forming apparatus according to any one of configurations 1 to 9, wherein when an outflow direction vector of the induced flow supplied from the plasma actuator is decomposed, the outflow direction vector has a directional component that is parallel to and opposite to the tangent vector. (Configuration 12) In a direction from the edge of the first electrode along the exposed portion of the first surface of the dielectric A point where the extension line intersects with the surface of the electrophotographic photosensitive member is taken, and a velocity vector in the rotation direction of the electrophotographic photosensitive member on a tangent line to the surface of the electrophotographic photosensitive member at the point is taken as a tangent vector. 12. The electrophotographic image forming apparatus according to any one of Structures 1 to 11, wherein when an extension line from the edge of the first electrode in a direction along the exposed portion of the first surface of the dielectric forms an narrow angle θ with respect to the tangent vector, the narrow angle θ is 0° to 90°. (Configuration 13) 13. The electrophotographic image forming apparatus according to Configuration 12, wherein the narrow angle θ is 10° to 45°. (Configuration 14) 5. An electrophotographic imaging apparatus according to configuration 4, wherein the second electrode of the plasma actuator is the support member of the electrophotographic cleaning blade. (Configuration 15) 15. The electrophotographic image forming apparatus according to any one of Configurations 1 to 14, wherein the dielectric material of the plasma actuator is a polyurethane resin. (Configuration 16) 16. The electrophotographic image forming apparatus according to any one of Configurations 1 to 15, wherein the velocity of the induced flow at a position 1.0 mm away from the tip of the plasma actuator in the supply direction of the induced flow, as measured by particle image velocimetry, is 0.15 to 1.00 m / sec. (Configuration 17) 17. The electrophotographic image forming apparatus according to any one of Configurations 1 to 16, wherein a DC voltage is applied between the first electrode of the plasma actuator and the electrophotographic photosensitive member. (Configuration 18) A process cartridge detachably mounted in an electrophotographic image forming apparatus, The process cartridge includes an electrophotographic photosensitive member, a cleaning member in contact with the surface of the electrophotographic photosensitive member, and a plasma actuator. The plasma actuator comprises: A dielectric material; a first electrode provided on a first surface of the dielectric; a second electrode 2 provided on the first electrode with the dielectric sandwiched therebetween; By applying an AC voltage between the first electrode and the second electrode, the plasma actuator generates an induced flow from an edge of the first electrode along an exposed portion of the first surface of the dielectric material that is not covered by the first electrode; The plasma actuator is disposed so as to be capable of directly supplying the induced flow to the surface of the electrophotographic photosensitive member, and controls the potential of the transfer residual toner on the surface of the electrophotographic photosensitive member. (Configuration 19) Controlling the potential of the transfer residual toner removing static electricity from the transfer residual toner by the induced flow; and charging the transfer residual toner by the induced flow to the same polarity as the polarity of the surface of the electrophotographic photosensitive member; 19. The electrophotographic image forming apparatus according to embodiment 18, wherein the at least one selected from the group consisting of: (Configuration 20) 20. The process cartridge according to claim 18 or 19, wherein the first electrode and the second electrode are arranged diagonally opposite each other with the dielectric material therebetween.

Claims

1. An electrophotographic image forming apparatus comprising an electrophotographic photoreceptor as a charged object, a cleaning member in contact with the surface of the electrophotographic photoreceptor, and a plasma actuator, The plasma actuator is Dielectrics and A first electrode provided on the first surface of the dielectric, The device comprises a first electrode and a second electrode provided with the dielectric material in between, By applying an alternating voltage between the first electrode and the second electrode, the plasma actuator generates an induced flow from the edge of the first electrode along the exposed portion of the first surface of the dielectric that is not covered by the first electrode. An electrophotographic image forming apparatus characterized in that the plasma actuator is positioned to directly supply the induced flow to the surface of the electrophotographic photoreceptor and controls the potential of the residual toner on the surface of the electrophotographic photoreceptor.

2. Controlling the potential of the residual toner is The induced flow removes static electricity from the remaining toner, and The electrophotographic image forming apparatus according to claim 1, wherein the polarity of the transfer residue toner due to the induced flow is at least one selected from the group consisting of charging to the same polarity as the surface polarity of the electrophotographic photoreceptor.

3. The electrophotographic image forming apparatus according to claim 1, wherein the potential of the residual toner is controlled before the residual toner enters the contact area between the cleaning member and the electrophotographic photoreceptor.

4. The electrophotographic image forming apparatus according to claim 1, wherein the cleaning member is an electrophotographic cleaning blade having an elastic member and a support member for supporting the elastic member, and for cleaning the surface of the electrophotographic photoreceptor.

5. The electrophotographic image forming apparatus according to claim 1, wherein the plasma actuator is disposed on the surface of the cleaning member.

6. When the plasma actuator is viewed through from the surface side of the first electrode, At least a portion of the edge of the first electrode has an overlapping portion with the second electrode, The electrophotographic image forming apparatus according to claim 1, wherein the length A between the edge of the first electrode and the edge of the second electrode forming the overlapping portion is 0 to 1000 μm.

7. The electrophotographic image forming apparatus according to claim 1, wherein the first electrode and the second electrode are arranged diagonally opposite each other with the dielectric material in between.

8. The electrophotographic image forming apparatus according to claim 1, wherein the height of the largest protrusion at the edge of the first electrode is 0 to 40 μm and the width is 0 to 40 μm.

9. The electrophotographic image forming apparatus according to claim 1, wherein the plasma actuator directly supplies the induced flow upstream of the contact portion between the cleaning member and the electrophotographic photoreceptor in the rotational direction of the electrophotographic photoreceptor.

10. The point where the extension line from the edge of the first electrode along the exposed portion of the first surface of the dielectric intersects the surface of the electrophotographic photoreceptor is taken, and the tangent vector is the velocity vector in the rotational direction of the electrophotographic photoreceptor on the tangent line to the surface of the electrophotographic photoreceptor at that point. The electrophotographic image forming apparatus according to claim 1, wherein when the outflow direction vector of the induced flow supplied from the plasma actuator is decomposed, the outflow direction vector has a directional component that is parallel to and in the same direction as the tangent vector.

11. The point where the extension line from the edge of the first electrode along the exposed portion of the first surface of the dielectric intersects the surface of the electrophotographic photoreceptor is taken, and the tangent vector is the velocity vector in the rotational direction of the electrophotographic photoreceptor on the tangent line to the surface of the electrophotographic photoreceptor at that point. The electrophotographic image forming apparatus according to claim 1, wherein when the outflow direction vector of the induced flow supplied from the plasma actuator is decomposed, the outflow direction vector has a directional component that is parallel to and opposite to the tangent vector.

12. The point where the extension line from the edge of the first electrode along the exposed portion of the first surface of the dielectric intersects the surface of the electrophotographic photoreceptor is taken, and the tangent vector is the velocity vector in the rotational direction of the electrophotographic photoreceptor on the tangent line to the surface of the electrophotographic photoreceptor at that point. The electrophotographic image forming apparatus according to claim 1, wherein when the narrow angle θ is defined as the angle made with the tangent vector by the extension line extending from the edge of the first electrode in the direction along the exposed portion of the first surface of the dielectric, the narrow angle θ is between 0° and 90°.

13. The electrophotographic image forming apparatus according to claim 12, wherein the narrow angle θ is 10° to 45°.

14. The electrophotographic image forming apparatus according to claim 4, wherein the second electrode of the plasma actuator is the support member of the electrophotographic cleaning blade.

15. The electrophotographic image forming apparatus according to claim 1, wherein the dielectric of the plasma actuator is a polyurethane resin.

16. The electrophotographic image forming apparatus according to claim 1, wherein the velocity of the induced flow at a position 1.0 mm away from the leading edge in the supply direction of the induced flow in the plasma actuator, as measured by particle image velocity measurement, is 0.15 to 1.00 m / sec.

17. The electrophotographic image forming apparatus comprises the first electrode of the plasma actuator and the An electrophotographic image forming apparatus according to any one of claims 1 to 16, wherein a DC voltage is applied between electrophotographic photoreceptors.

18. A process cartridge that can be attached to and detached from an electrophotographic image forming apparatus, The process cartridge comprises an electrophotographic photoreceptor, a cleaning member in contact with the surface of the electrophotographic photoreceptor, and a plasma actuator. The plasma actuator is Dielectrics and A first electrode provided on the first surface of the dielectric, The device comprises a first electrode and a second electrode 2 provided with the dielectric material in between, By applying an alternating voltage between the first electrode and the second electrode, the plasma actuator generates an induced flow from the edge of the first electrode along the exposed portion of the first surface of the dielectric that is not covered by the first electrode. A process cartridge characterized in that the plasma actuator is positioned to directly supply the induced flow to the surface of the electrophotographic photoreceptor and controls the potential of the residual toner on the surface of the electrophotographic photoreceptor.

19. Controlling the potential of the residual toner is The induced flow removes static electricity from the remaining toner, and The charge of the polarity of the transfer residue toner due to the induced flow to be the same polarity as the polarity of the surface of the electrophotographic photoreceptor, The process cartridge according to claim 18, which is at least one selected from the group consisting of the following.

20. The process cartridge according to claim 18 or 19, wherein the first electrode and the second electrode are arranged diagonally opposite each other with the dielectric in between.

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