JP2002268327A - Charging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To uniformly and stably charging a photoreceptor drum 11, rotated at a high speed in a charging device using a cylindrical conductive film 30. SOLUTION: A conductive support body (for example, a feed support roll 40) rotatably supporting the conductive film 30 is rotated at a circumferential speed S45 higher than a circumferential speed S11 of the rotation of the photoreceptor drum 11. In this case, the film 30 drivingly rotates by the drum 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylindrical conductive film which is rotatably supported in contact with a rotating member to be charged, and which is formed between the conductive film and the member to be charged. Contact-type charging device that generates electric discharge in a minute gap, mainly in an image forming apparatus such as a copying machine, a printer, a facsimile, and a multifunction machine using electrophotography, electrostatic recording, and the like. The present invention relates to a charging device suitably used as a charging device for charging a carrier or the like to a desired potential.

[0002]

2. Description of the Related Art In an image forming apparatus utilizing an electrophotographic method or the like, generally, the surface of an image carrier such as a photoreceptor rotating in a fixed direction is uniformly charged to a desired potential by a charging device. An electrostatic latent image formed by exposing the charged surface of the image carrier to light according to image information is developed with a developer to form a toner image, and thereafter, the toner image on the image carrier is converted to a toner image. An image is formed by transferring the image onto a recording medium such as a recording sheet directly or via an intermediate transfer member and finally fixing the image.

In recent years, as a charging device used in such an image forming apparatus, a contact-type charging device using a cylindrical conductive film as a charging member has been proposed. This type of charging device is, for example, as shown in FIG. 9, so that the cylindrical conductive film 110 is rotated while being in contact with the image carrier 120, from the inner peripheral surface side of the conductive film 110. After being rotatably supported by a conductive support 130 such as a roll, a charging voltage is applied from a power supply 140 to the conductive film 110 via the conductive support 130, and the conductive film 110 and the image are charged. The surface of the image carrier 120 is charged to a predetermined potential by generating a discharge in a minute gap formed between the image carrier 120 and the carrier 120. In this case, the cylindrical conductive film 1
In the case of 10, the inner diameter is set to a value larger than the outer diameter of the conductive support 130. In addition, since the conductive support 130 is rotatably supported, no rotational power is applied.

The cylindrical conductive film 11
According to the charging device using 0, for example, compared with a charging device using an elastic roll (for example, a conductive rubber roll) as a charging member, the contact with the image carrier 120 can be made uniform and at a low pressure. This makes it possible to simplify charging, simplify the support structure, and reduce the load on the surface of the image carrier.

[0005]

However, on the other hand,
When the charging device using the cylindrical conductive film 110 attempts to perform the charging process at a higher speed (that is, for example, when charging the image carrier 120 that rotates at a peripheral speed of 300 mm / sec or more), There has been a technical problem that the charging potential (surface potential) of the image carrier 120 fluctuates and it is difficult to perform uniform and stable charging.

More specifically, in the charging device described above, at the initial stage of the charging start, as shown in FIG. 10A, the conductive film 110 is attracted to the image carrier 120 by electrostatic attraction. Image carrier 120
As the conductive film 110 rotates, the conductive support member 130 is also driven to rotate with the rotation of the conductive film 110. As a result, the conductive film 110 has a portion N in contact with the image carrier 120 as a center, on the upstream side (front side of the contact portion N) and on the downstream side (rear side behind the contact portion N) in the rotation direction. It is rotating in a slack state. Then, mainly, a discharge is generated in a minute gap formed between the slack portion 110a of the conductive film 110 which is in front of the contact portion N and the image carrier 120, and the image carrier 120 is charged. .

However, when the image carrier 120 rotates at a high speed, as shown in FIG. 10B, the slack portion 110 on the front side of the contact portion N of the conductive film 110 is used.
a decreases, and the slack portion 110b on the rear side of the passage of the contact portion N increases accordingly. In addition, the slack amount of the slack portion 110a of the conductive film 110 which is in front of the contact portion N may slightly increase or decrease. Due to such a change in the behavior of the conductive film 110, the charging performance also fluctuates.
It is presumed that the charging potential of No. 20 fluctuates.

By the way, such a conductive film 11
In order to eliminate the movement of the zero slack portion, for example, as shown in FIG.
A countermeasure in which regulating members 150 and 151 for regulating the pressure are arranged can be considered. The restricting members 150 and 151 are made of, for example, a metal shaft, and are arranged at a position where the conductive film 110 can be held so as to rotate in a state where the conductive film 110 is always slack (protruding) in front of the contact portion N. It is. Thereby, it is possible to secure a large dischargeable minute gap between the conductive film 110 and the image carrier 120 in front of the contact portion N. However, in this countermeasure, there is a problem that an extra regulating member is required, cost is increased, and assembly and structure of the entire charging device are complicated.

The present invention has been made in view of such circumstances, and a main object of the present invention is to provide a charging device using a cylindrical conductive film as a charging device that rotates at a high speed. Another object of the present invention is to provide a charging device capable of performing uniform and stable charging with a simple configuration.

[0010]

According to the present invention, there is provided a charging device according to the present invention, comprising: a cylindrical conductive film in contact with a rotating member to be charged; A conductive support that satisfactorily supports, and a power supply that applies a voltage to the conductive film through the conductive support, and a minute gap formed between the conductive film and the member to be charged. Wherein the conductive support is rotated at a peripheral speed higher than the peripheral speed of rotation of the member to be charged.

Here, the conductive support is preferably rotated at a peripheral speed that is about 1.2 to 2.5 times the peripheral speed of rotation of the member to be charged. Further, in order to rotate the conductive support with such a peripheral speed difference, for example, the conductive support may be configured to be rotated by a rotation drive unit that is independent of the rotation drive unit of the member to be charged. Alternatively, a configuration may be adopted in which a rotating power is applied to the conductive support from a rotation driving unit of the charged body via a speed increasing type rotation transmission mechanism to rotate the conductive support. Note that the conductive support is supported in a state where the conductive support is in contact with the member to be charged via the conductive film.

In such a charging device, while the cylindrical conductive film is rotatably supported by the conductive support, it is pulled by the electrostatic attraction to the rotating member to be charged and rotates in a state of being in close contact therewith. . At this time, since the conductive support rotates at a peripheral speed higher than the peripheral speed of rotation of the member to be charged, the conductive film supported by the conductive support is separated from the member to be charged by the difference in the peripheral speed. It is in a state of being fed one after another toward the front side of the contact portion. As a result, the conductive film rotates in such a manner that it always slackens in front of the contact portion with the member to be charged. This becomes more remarkable as the member to be charged rotates at a higher speed. As a result, a small gap capable of discharging between the conductive film and the member to be charged is always stably secured on the front side of the contact portion, and uniform and stable charging is possible.

It is preferable that the conductive film and the conductive support are made of materials having the same or similar charging lines arranged in the order of positive and negative charging. As a result, the conductive film and the conductive support are electrostatically charged due to friction generated between the charged body, the conductive film that is driven to rotate, and the conductive support that rotates at a higher peripheral speed than the charged body. It is possible to prevent the unnecessary rotation of the conductive film from becoming unstable due to the generation of unnecessary charges that are attracted to the conductive film. Thereby, a minute gap formed before the contact portion between the conductive film and the member to be charged can be stably obtained.

The conductive support may be, for example, a rotating roll having conductivity. In this case, the conductive film is larger than the outer diameter of the rotating roll (for example, the outer diameter thereof). It is good to have a cylindrical shape having an inner diameter of about 1.07 to 1.5 times the above. In this case, a minute gap capable of discharging can be formed more easily and reliably before the contact portion between the conductive film and the member to be charged. The rotating roll is preferably an elastic roll having an elastic layer formed on a rotating shaft.

Further, the conductive support may be a cylindrical rotating brush having electrical conductivity (a brush roll having a structure in which a brush stands on a rotating shaft).
In this case, the conductive film may have a cylindrical shape having an inner diameter substantially equal to the outer diameter of the rotating brush. In this case, the area and pressure of the contact portion of the rotating brush with the member to be charged via the conductive film can be reduced as compared with the case of the rotating roll. As a result, there is an effect that the contact pressure on the member to be charged can be further reduced.

Although the charging device of the present invention includes a rotating member to be charged, it can be used without any particular limitation as a charging device.
It is effective to use the charging device as a charging device for charging an image carrier that electrostatically carries an image formed of toner. Examples of such an image bearing member include a photosensitive member (drum-shaped or belt-shaped) and an intermediate transfer member in an image forming apparatus such as a printer, a copying machine, and a facsimile using an electrophotographic method, an electrostatic recording method, or the like. The image forming apparatus may be for a monochrome image or a color image. Further, the charging device of the present invention is used for the charging device in the above-described image forming apparatus and the like, and also has a surface potential of the member to be charged of substantially zero.
It can also be used as a static eliminator charged to V.

[0017]

Embodiments of the present invention will be described below with reference to the drawings.

Embodiment 1 FIGS. 1 and 2 show Embodiment 1 of the present invention. FIG. 1 shows a charging device of the present invention, and FIG. 2 shows an image to which the charging device of the present invention is applied. 1 shows a forming apparatus.

As shown in FIG. 2, the image forming apparatus includes a charging device 12 for charging the surface of the photosensitive drum 11 around the photosensitive drum 11 rotating in the direction of arrow A, and a charging device 12 for charging the surface of the charged photosensitive drum 11. A latent image writing device 13 for exposing light corresponding to image information to write an electrostatic latent image;
A developing device 14 for developing the electrostatic latent image written in 1 with a developer (toner); a transfer device 15 for transferring a toner image formed on the photosensitive drum 11 to recording paper P;
6 and so on are provided. Further, in FIG.
Reference numeral 0 denotes a paper feeder that accommodates a plurality of recording papers P and feeds the recording papers P one by one toward a transfer position, 21 denotes a registration roll that feeds the recording papers P between the photosensitive drum 11 and the transfer device 15 at a predetermined timing, A fixing device 25 fixes the unfixed toner image transferred onto the recording paper P.

The photosensitive drum 11 is formed, for example, by laminating a photoconductive layer 1b on a cylindrical conductive base material 11a.
The conductor base 11a is electrically grounded. As the latent image writing device 13, a laser scanning exposure device is used.
The present invention is not limited to this, and may be an LED exposure device or the like. The transfer device 15 includes a transfer roll 15a that rotates in contact with the photosensitive drum 11, and a transfer bias power supply 1 that applies a transfer bias having a polarity opposite to the charging polarity of the toner to the transfer roll 15a.
5b. As the toner in the developing device 14, a spherical toner having good transfer efficiency is used. By the way, this image forming apparatus uses the photosensitive drum 1
A cleaner-less system that does not use a cleaner that removes minute deposits such as toner adhered to 1 is adopted. If necessary, a cleaner (17) is provided as shown by a two-dot chain line in FIG. No problem.

As shown in FIG. 1 and the like, the charging device 12 has a conductive film 30 formed in a cylindrical shape, and the conductive film 30 in contact with the photosensitive drum 11 so as to be rotatable inside the photosensitive drum 11. The main part is constituted by a power supply support roll 40 arranged to support the power supply support roll 40 from above and a power supply device 50 for applying a DC charging bias to the power supply support roll 40.

The conductive film 30 has a cylindrical shape, and conductive particles such as carbon black are mixed and dispersed in a synthetic resin film to have a volume resistivity of 10%.
Prepared to be ³ to 10 ¹⁰ Ω · cm, and the thickness is 30 to
It is formed using a semiconductive film member having a flexibility of about 200 μm. As the synthetic resin film, for example, polyamide, polyester, polyimide, polyethylene, polycarbonate, polyolefin, polyurethane, polyvinylidene fluoride, acrylic and the like are used. The conductive film 30 is formed in a circular shape whose inner diameter R ₃₀ is set to be about 1.07 times larger than the outer diameter R _{40 of} the power supply support roll 40. The relationship is such that there is a gap between them.

The power supply supporting roll 40 includes a conductive rotating shaft 4.
1 has a roll structure in which a conductive elastic layer 42 is formed on the photosensitive drum 11 via the conductive film 30 while the elastic layer 42 is in contact with the photosensitive drum 11. 41 are supported. The elastic layer 42 is formed of, for example, a material such as nylon, polyurethane, or polyamide. The elastic layer 42 is formed on a smooth surface so that its surface has low frictional resistance with respect to the inner peripheral surface of the conductive film 30.

The power supply device 50 is a DC power supply that generates a DC voltage as a charging bias.
Is electrically connected to the rotating shaft 41 of the second motor. As the power supply device 50, a device that applies a voltage in which an AC component is superimposed on a direct current as a charging bias may be used as necessary.

In this charging device, FIG.
As shown in FIG. 7, the power supply support roll 40 receives a predetermined rotational driving force from an electric motor 60 that rotationally drives the photosensitive drum 11 via a speed increasing type rotation transmission mechanism 61 of a gear train type or a belt type. by being transmitted by a speed increasing ratio, and rotates drive at a peripheral speed S ₄₀ to be 1.5 times the peripheral speed S ₁₁ of rotation of the photosensitive drum 11.
Although the photosensitive drum 11 is directly connected to the electric motor 60 in the illustrated example, the photosensitive drum 11 may be connected to the electric motor 61 via a predetermined rotation transmission mechanism. Reference numeral 62 in the figure,
63 denotes a bearing.

Next, an image forming operation of the image forming apparatus using such a charging device 12 will be described.

First, the photosensitive drum 11 rotates at a constant speed (peripheral speed S ₁₁ ) in the direction of arrow A, and the surface of the photosensitive drum 11 is charged by the charging device 12 so as to have a constant potential (V _H ). After that, the optical image is scanned and exposed by the latent image writing device 13 to write an electrostatic latent image, and the latent image is developed with the developer (toner) of the color housed in the developing device 14 so that the photosensitive image is exposed. A toner image is formed on the drum 11.

Next, the toner image on the photosensitive drum 11 is transferred from the photosensitive drum 11 to the transfer device 15 by a paper feeding device 20.
After being electrostatically transferred to the recording sheet P conveyed to the transfer position between the (transfer rolls 15a), the transferred recording sheet P is sent to the fixing device 25 and subjected to a fixing process (for example, heating). The recording paper P is fixed by the pressure. Thus, a basic image is formed on one recording sheet P. On the other hand, the surface of the photosensitive drum 11 after the transfer is neutralized by the neutralization device 16, and the charging device 12 starts the charging process again to perform the next image forming process.

Next, the operation of the charging device 12 will be described in detail.

When the charging device 12 is charged, as shown in FIG. 3A, a DC charging bias is applied to the conductive film 30 from the power supply device 50 via the power supply support roll 40. By applying this voltage, the cylindrical conductive film 30 is brought into close contact with the surface of the photosensitive drum 11 by electrostatic attraction generated between the conductive film 30 and the photosensitive drum 11. When the photosensitive drum 11 rotates in the direction of arrow A,
As shown in FIG. 3B, the power supply support roll 40 rotates and moves in the direction of arrow B while being supported by the power supply support roll 40 in a form bent so as to be pulled in the rotation direction A.

The photosensitive drum 11 is driven by an electric motor 61.
When rotated at the peripheral speed S ₁₁ , the power supply support roll 40 is driven to rotate at the peripheral speed S ₄₀ (> S ₁₁ ) by the rotational power transmitted through the speed increasing type rotation transmission mechanism 61. In addition,
The conductive film 30 rotates (at the same peripheral speed) following the photosensitive drum 11. Thereby, the conductive film 30
Rotates with a slack (30a) always before the contact portion N with the photosensitive drum 11 (FIG. 3).
b). As a result, a dischargeable minute gap is formed between the conductive film 30 and the photosensitive drum 11 on the front side of the contact portion N. The dischargeable area E due to the minute gap increases as the conductive film 30 sags and protrudes to the front of the contact portion N. And
Since the conductive film 30 always rotates in a slack state, the dischargeable region E is stably secured, and uniform and stable charging is performed.

Since the image forming apparatus using the charging device 12 is a cleanerless system as described above, residual toner exists on the photosensitive drum 11 after transfer, and the residual toner reaches the charging device 12. However, there is no problem in practical use. That is, since the contact pressure of the conductive film 30 and the power supply support roll 40 on the photosensitive drum 11 in the charging device 12 is small, deformation of the toner sandwiched between the charging device 12 and the photosensitive drum 11 is less likely to occur. As a result, the adhesion of the toner to the conductive film 30 is reduced, so that the toner is difficult to adhere to the toner.

FIG. 4 shows the results of a test in which charging characteristics of the charging device 12 were measured.

In this test, a 100 μm-thick polyamide film (volume resistivity: 10 ⁶ Ω · cm) formed into a cylindrical shape (tube shape) having an inner diameter of 15 mm was used as the conductive film 30. Power supply support roll 4
As 0, stainless steel shaft 41 (diameter: 8 mm)
(Roll diameter: 14 mm) on which an elastic layer 42 made of a polyamide foam was formed. Then, a DC voltage (−100) is supplied from the power supply 50 to the power supply support roll 40.
0V) and rotating the power supply support roll 40 at a peripheral speed of 240 mm / sec.
The charging of the photosensitive drum (organic photosensitive layer formed was drum) 11 which rotates conducted at a peripheral speed S ₁₁ of 160 mm / sec.
At this time, the surface potential (charge potential V _H ) of the photosensitive drum 11
Was measured by a surface potential sensor.

FIG. 5 shows, for comparison, in the charging device 12 used in the above-described test, the power supply support roll 40 is rotated at the same peripheral speed as the photosensitive drum 11 (the conductive film 3).
This figure shows the results when a charging device (comparative example) was prepared in which the point of rotation (subsequent rotation through 0) was changed and the above-described test was performed in the same manner.

[0036] From the results of FIGS. 4 and 5, the charging device of the comparative example, the maximum fluctuation range of the surface potential V _H of the photosensitive drum 11 delta
While V _H was about 18 V, it was confirmed that the maximum fluctuation width Δ was suppressed to about 10 V in the charging device 12 of this embodiment. Thereby, the charging device 12 of the present embodiment is
According to this, it was confirmed that the photosensitive drum 11 rotating at high speed could be charged uniformly and stably.

Next, the charging characteristics of the charging device 12 when the material of the conductive film 30 and the material of the elastic layer 42 of the power supply support roll 40 were changed from the relationship of the charging sequence were examined.

In this test, the materials having the charging sequence shown in FIG. 6A were used, and the charging characteristics were examined in combinations shown in the table of FIG. 6B. Test sample 1 is an example of the charging device used in the test. Evaluation,
The variation (ΔV _H ) of the surface potential V _H of the photosensitive drum 11 when charging was performed by each charging device using each material was examined, and the result was evaluated according to the following criteria. ：: When ΔV _H is less than 15 V ×: When ΔV _H is 15 V or more

From the results shown in FIG. 6B, it can be seen that the same and close charging columns are used as the material of the conductive film 30 and the material of the elastic layer 42 of the power supply support roll 40 (test samples 1, 3, and 4). In the case of (2), a good charging result was obtained, and the result was bad when a device having a distant charging line was used (test sample 2).

[Second Embodiment] FIG. 7 shows a charging device according to a second embodiment of the present invention. The charging device 12 has the same configuration as the charging device 12 according to the first embodiment except that a rotating power supply support brush (rotating roll brush) 45 is used instead of the power supply support roll 40. Here, the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

The power supply support brush 45 includes a conductive rotating shaft 4.
6 has a structure in which conductive brush bristles 47 are evenly erected, and a free end portion of the brush bristles 47 is in contact with the photosensitive drum 11 via the conductive film 30 so that a bearing frame not shown The rotary shaft 46 is supported on the shaft. As the brush bristles 47, for example, synthetic fibers having flexibility and conductivity (specifically, SA-7 or the like) are used. Further, the brush bristle 47 is processed into a rounded tip shape so that the free tip surface is not sharply applied to the inner peripheral surface of the conductive film 30 to be damaged.

Further, similarly to the power supply support roll 40 in the first embodiment, the power supply support brush 45 is driven to rotate at a peripheral speed S ₄₅ which is about 1.5 times the peripheral speed S ₁₁ of the rotation of the photosensitive drum 11. It is supposed to. Further, the power supply support brush 45 supports the contact portion N with the photosensitive drum 11 such that the width (the length in the rotation direction A) of the contact portion N is about 1 mm.

When the power supply support brush 45 is used, a circular film whose inner diameter R ₃₀ is substantially the same as the outer diameter R _{45 of the} power supply support brush 45 is used as the conductive film 30. Further, the conductive film 30
When a material made of a polyamide film is used as the brush bristles 47 of the power supply support brush 45, for example, polyamide fibers having the same charging line are used.

Even in the charging device 12 using the power supply support brush 45, when charging is performed, a DC charging bias is applied to the conductive film 30 from the power supply device 50 via the power supply support brush 45. . By the application of this voltage, the cylindrical conductive film 30 is moved to the photosensitive drum 1
1 and the photosensitive drum 11
Is brought into close contact with the surface. When the photosensitive drum 11 rotates in the direction of arrow A, the photosensitive drum 11 is bent and pulled in the direction of rotation A, and rotates and moves in the direction of arrow B while being supported by the power supply support brush 45.

When the photosensitive drum 11 rotates at the peripheral speed S ₁₁ , the power supply supporting brush 45 is rotated by the rotational power transmitted via the speed-increasing type rotation transmission mechanism 61 (FIG. 1B) to generate the peripheral speed S ₄₅ (> S). ₁₁ ) Rotation drive. As a result, FIG.
As shown in (1), the conductive film 30 slightly sags on the front side of the contact portion N with the photosensitive drum 11 (30a).
Rotate in a state with As a result, the conductive film 30 and the photosensitive drum 1
1 and a small gap capable of discharging is formed. The dischargeable area E due to the minute gap increases as the conductive film 30 slightly sags and protrudes to the front of the contact portion N. Then, the conductive film 30
Since the rotation is always performed in a loose state, the dischargeable area E is stably secured, and uniform and stable charging is performed.

Further, when the respective tests in Embodiment 1 were similarly performed on the charging device 12, substantially the same results were obtained.

The following test was conducted to check the charging performance of each charging device 12 according to the first and second embodiments. That is, when a DC voltage of 0 V to -2000 V was applied to the power supply support roll 40 and the power supply support brush 45 from the power supply device 50, the surface potential of the photosensitive drum 11 was measured. Also, the surface potential of the photoreceptor drum 11 started to rise sharply from the time when a voltage of about -550 V was applied, and reached a value of about -1450 V when a voltage of -2000 V was applied. During this time, occurrence of abnormal discharge from the conductive film 30 was not observed. As a result, it was verified that the charging device 12 according to the first and second embodiments has a charging performance that can be used as a charging device for the photosensitive drum 11 without practical problems.

[0048]

As described above, according to the charging device of the present invention, in the charging device using the cylindrical conductive film, the conductive support rotatably supporting the conductive film is provided with the charged object. Since the rotation is performed at a peripheral speed higher than the peripheral speed of the rotation, uniform and stable charging can be performed even on the object to be charged rotating at a high speed. That is,
It has excellent suitability for high-speed charging.

[Brief description of the drawings]

FIG. 1 shows a charging device according to a first embodiment,
(A) is the front side schematic diagram, (b) is the side surface schematic diagram.

FIG. 2 is a schematic explanatory view showing an image forming apparatus to which the charging device of FIG. 1 is applied.

3A and 3B are diagrams illustrating a state of a conductive film in the charging device of FIG. 1, wherein FIG. 3A is a schematic explanatory view illustrating a state when a photosensitive drum and a power supply support roll are stopped, and FIG. FIG. 4 is a schematic explanatory view showing a state when a power supply support roll is rotating.

FIG. 4 is a graph showing the results of a charging characteristic test for the charging device of FIG. 1;

FIG. 5 is a graph showing the results of a charging characteristic test on a charging device of a comparative example.

FIGS. 6A and 6B show a charging characteristic test based on material selection and the results thereof. FIG. 6A is an explanatory diagram showing a charging sequence, and FIG. 6B is a chart showing the test conditions and results.

FIG. 7 is a schematic front view showing the charging device according to the second embodiment.

FIG. 8 is a schematic explanatory view showing a state of a conductive film during charging by the charging device of FIG. 7;

FIG. 9 is a conceptual diagram showing a conventional charging device using a conductive film.

10A and 10B show a state of a conductive film in the charging device of FIG. 9, wherein FIG. 10A is a schematic explanatory view showing a state at an initial stage of rotation, and FIG. FIG.

FIG. 11 is a conceptual diagram showing a charging device having a configuration in which a conductive film is regulated by a regulating member.

[Explanation of symbols]

11 photosensitive drum (charged body), 12 charging device, 30
... conductive film, 40 ... power supply support roll (conductive support, rotating roll), 45 ... power supply support brush (conductive support, rotary brush).

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Katsuya Takenouchi, 2274 Hongo, Ebina-shi, Kanagawa Prefecture, within Fuji Xerox Co., Ltd. Terms (reference) 2H200 HA04 HA29 HB12 HB13 HB22 HB23 HB31 HB45 HB46 HB47 MA04 MB01 MC14 NA09 PA11

Claims (4)

[Claims] 1. A cylindrical conductive film which comes into contact with a rotating member to be charged, a conductive support which rotatably supports the conductive film from an inner peripheral surface side thereof, and a conductive support interposed therebetween. A power supply for applying a voltage to the conductive film, and generating a discharge in a minute gap formed between the conductive film and the member to be charged, wherein the conductive support, A charging device characterized in that it is rotated at a peripheral speed higher than the peripheral speed of rotation of the charged body. 2. The charging device according to claim 1, wherein the conductive film and the conductive support are made of materials having the same or similar charging sequence. 3. The charging device according to claim 1, wherein the conductive support is a rotating roll, and the conductive film has a cylindrical shape having an inner diameter larger than an outer diameter of the rotating roll. A charging device characterized by the above-mentioned. 4. The charging device according to claim 1, wherein said conductive support is a cylindrical rotating brush, and said conductive film has an inner diameter substantially equal to an outer diameter of said rotating brush. A charging device, characterized in that: