JPH0695560A - Image carrier and its manufacture, contact charging method and device, process cartridge and image forming device - Google Patents

Abstract

PURPOSE:To provide an image carrier, process cartridge, and an image forming device, with which generation of electric charging sounds can be suppressed. CONSTITUTION:As an image carrier a sensitive drum 3 is provided which undergoes an electric charging processing when contacted by an electric charging roller 4 on which a voltage is impressed, and a rigid or elastic filler 3c is installed inside of this drum 3. When the gap to the filler 3c exceeds 100mum, it is secured to the drum inner surface by a foaming substance or a sealing material. This accomplishes suppression of drum vibrations as the main cause of electric charging sound, and the generation of such sounds can be suppressed even in case the frequency of AC voltage to be impressed on the roller 4 is set high.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image carrier, a method for manufacturing the same, a process cartridge using the image carrier, an image forming apparatus, a charging method for charging the image carrier, and a charging device.

[0002]

2. Description of the Related Art Conventionally, in an image forming apparatus such as a laser beam printer (LBP) or a copying machine utilizing an electrophotographic process or an electrostatic recording process, an image carrier such as an electrophotographic photosensitive member or an electrostatic recording dielectric is used. A non-contact type corona discharge device has been generally adopted as a charging device for charging.

However, recently, since it has advantages such as a low power supply voltage and a very small amount of ozone generated, a roller type or blade type charging member (conductive member) to which a voltage is applied is provided. ) Is being adopted.

FIG. 23 shows a specific example thereof. In FIG. 23, reference numeral 101 denotes, for example, a rotating drum type electrophotographic photosensitive member (hereinafter referred to as a photosensitive drum) as a cylindrical image bearing member. The photosensitive drum 101 includes an organic photosensitive layer 101 on an outer peripheral surface of a drum base 101a made of, for example, aluminum.
b is formed, which is rotationally driven in the direction of the arrow (clockwise direction) at a predetermined peripheral speed (process speed).

Reference numeral 102 denotes a charging roller which is a charging member brought into contact with the photosensitive drum 101 and which is driven to rotate as the photosensitive drum 101 rotates. This charging roller 10
Reference numeral 2 denotes a conductive elastic layer 10 such as urethane rubber containing carbon on the outer peripheral surface of the conductive core metal 102a such as iron or SUS.
2b, the charging roller 102 is pressed against the surface of the photosensitive drum 101 by spring members (not shown) at both ends in the longitudinal direction of the conductive cored bar 102a.

When a voltage having a predetermined polarity and potential is applied to the conductive core metal 102a of the charging roller 102 by the high voltage power source 103, the peripheral surface of the photosensitive drum 101 is contacted by the charging roller 102. It is charged.

In addition to the charging roller 102, necessary image forming process equipment such as an exposing means, a developing means, a transferring means, a cleaning means, a fixing means and a paper feeding means are arranged around and around the photosensitive drum 101. Although the entire image forming apparatus is constructed by the above, they are omitted in the drawing.

By the way, the charging roller 1 as a charging member.
The voltage applied to 02 may be only a DC voltage, but it is preferable to apply an oscillating voltage in which a DC voltage and an AC voltage are superimposed in order to make the charging uniform. It is preferable to apply an oscillating voltage obtained by superposing an AC voltage and a DC voltage having a peak-to-peak voltage that is at least twice the charging start voltage of the image carrier when only the DC voltage is applied to the charging member. (See JP-A-63-149669, etc.). The oscillating voltage referred to here is a voltage whose voltage value periodically changes with time, and may have a peak-to-peak voltage that is at least twice the charging start voltage of the surface of the image carrier when only a DC voltage is applied. Further, the waveform is not limited to the sine wave, and may be a rectangular wave or a triangular wave, but a sine wave containing no harmonic component is preferable from the viewpoint of reducing the charging noise.

[0009]

However, in the case where the oscillating voltage is applied to the charging roller 102 to charge the photosensitive drum 101 as described above, the photosensitive drum 1 is charged.
As the peripheral speed of 01 increases, this photosensitive drum 10
In order to ensure uniform charging of one surface, the charging roller 102
The frequency of the AC voltage applied to the photosensitive drum 10 must be increased, but if the frequency exceeds about 200 Hz, the photosensitive drum 10
1 and the charging roller 102 vibrate, so that a so-called "charging sound" becomes large. Generally, if the peripheral speed of the photosensitive drum is 50 mm / s,
To obtain a uniform image without charging pitch unevenness, 35
A frequency of about 0 to 400 Hz is required.

It has been clarified that the above phenomenon is caused by the following mechanism.

That is, when an AC voltage is applied to the charging roller 102, an attractive force due to an electrostatic force acts between the photosensitive drum 101 and the charging roller 102, and the maximum value portion and the minimum value portion of the AC voltage are mutually affected. The power to attract
The charging roller 102 is elastically deformed and attracted to the photosensitive drum 101, and the mutual attraction force becomes small at the center value of the AC voltage. Due to the elastic deformation recovery force of the charging roller 102, the charging roller 102 and the charging roller 102 are recovered. Try to leave. Therefore, the photosensitive drum 101 and the charging roller 102 vibrate at a frequency twice as high as the applied AC voltage.

Further, the photosensitive drum 101 and the charging roller 10
Although they rotate while moving in friction with each other, the electrostatic force exerts an attractive force to increase the mutual attractive force between the maximum value portion and the minimum value portion of the AC voltage, and the charging roller 102 is elastically deformed. While being attracted to the photosensitive drum 101, the brake is applied to the mutual rotational movement,
Further, the mutual attraction force becomes smaller at the center value of the AC voltage, and the elastic deformation recovery force of the charging roller 102 causes
This brake is relaxed when the photosensitive drum 101 and the charging roller 102 are about to separate from each other. For this reason, vibration due to stick-slip occurs as if the surface of the glass that was wet was rubbed with a finger. This vibration also occurs at a frequency twice as high as the applied AC voltage as described above.

The charging sound is caused by the vibration as described above,
Since this basically occurs at a frequency twice that of the applied AC voltage, for example, when the frequency of the AC voltage is 300 Hz, a sound of 600 Hz is observed. In addition to this, an integral multiple harmonic component, and rarely, a frequency of the applied AC voltage and an integral multiple harmonic component may be observed.

Such a charging sound is directly emitted as a sound from the contact portion between the photosensitive drum 101 and the charging roller 102, and the vibration of the photosensitive drum 101 is transmitted to, for example, a process cartridge or an image forming apparatus, and converted into a sound there. It may be done.

The problem and mechanism of the above-mentioned charging noise is as follows.
The charging member is not limited to a roller type (charging roller), but may be a blade type (charging blade), a pad type, a block type, a rod type, a wire type, or the like.

Therefore, an object of the first invention is to provide an image carrier, a process cartridge and an image forming apparatus capable of suppressing the generation of charging noise.

By the way, when the contact charging device is used as a charging means of an image forming apparatus for forming an electrostatic latent image by line scanning on an image bearing member which is a member to be charged, such as a laser beam printer, it is as follows. There is a problem.

That is, when an image pattern of repeated irradiation and non-irradiation of laser with high density at equal intervals in the sub-scanning direction is output, the frequency of the AC voltage applied to the contact charging member becomes close to the frequency of the image pattern. In this case, moire fringes may occur on the image surface. This problem can be solved by increasing the frequency of the AC voltage sufficiently. However, since the contact charging member and the image carrier are in contact with each other, the oscillating electric field formed between them causes the contact charging member and the image carrier. To facilitate the generation of charging noise.

As one of the means for solving the above problems, there is a method of inserting a filler into the image carrier to increase the weight of the image carrier. This method uses an elastic body as the surface layer of the filling material, press-fits the filling material having an outer diameter slightly larger than the inner diameter of the image bearing body into the image bearing body, and after the press-fitting, uses the elastic deformation of the surface layer to fill. This is a method of fixing an object in the image carrier. still,
The difference between the inner diameter of the image carrier and the outer diameter of the filler (hereinafter referred to as press-fitting margin) is generally set in the range of 0 to 1 mm in consideration of the type of elastic body, hardness, friction coefficient and the like.

However, the above method has the advantage that no means for fixing the filler in the image bearing member by adhesion or the like is required, but in order to perform stable press-fitting, the press-fitting margin and surface characteristics of the elastic body are required. It is necessary to suppress the variation of. In order to suppress the variation in the press-fitting margin of the elastic body, the surface of the elastic body must be polished after molding, and when surface polishing is performed, the surface characteristics of the elastic body such as surface roughness and friction coefficient are caused. Variation will occur.

In order to suppress the variation in the surface characteristics of the elastic body, no polishing may be performed, but the variation in the outer diameter of the filler cannot be suppressed as much as polishing, and in any case, it is necessary for press fitting. A large variation occurs in force (hereinafter, referred to as a pressure input), and in some cases, a large pressure input is required, which causes a problem that the image carrier is deformed.

Therefore, the object of the second invention is that even if the surface characteristics of the elastic body are varied, the pressure input can be made uniform and the filling can be pressed at a low pressure.
An object of the present invention is to provide a method of manufacturing an image carrier that can achieve low noise and high image quality.

By the way, as the waveform of the oscillating voltage applied to the charging member, generally, a sin wave, a rectangular wave, a triangular wave and the like can be mentioned, but a charging sound is generated in any waveform.

Since the above oscillating voltage waveform is a synchronous function,
It is possible to consider a composite wave of waves that are synchronized with each other and have an integer ratio.

That is, the periodic function (oscillating voltage waveform) f (t)
(T is time) is expressed by the following equation.

[0026]

[Equation 1] Here, ω: angular frequency (= 2πf) f: frequency A ₀ : direct current term A ₁ sin (ωt + φ ₁ ): fundamental wave The waveform used in the past can be rewritten into the above-mentioned form, and the amplitude can be changed. Let A be: i) For a square wave:

[0027]

[Equation 2] ii) For triangular waves:

[0028]

[Equation 3] Is represented.

Since the charging sound has a large frequency value which is twice the applied frequency, the amplitudes A ₁ of the fundamental waves of the sin wave, the rectangular wave and the triangular wave are sin waves: A ₁ = A rectangular wave In the case of: A ₁ = 4 / π · A In the case of a triangular wave: A ₁ = 8 / π ² · A, and it can be seen that the amplitude A ₁ of the fundamental wave in the conventionally used waveform is almost equal to A. Therefore, it is considered that the level of the charging noise is not so different.

As a method for suppressing the charging noise to a low level, there are a vibration countermeasure for suppressing the vibration of the body to be charged and a sound insulation countermeasure for preventing the sound from leaking out of the image forming apparatus.

As a method of suppressing the vibration of the body to be charged, when the body to be charged is a drum, there is a method in which a filling material is provided inside the drum, which increases the weight of the drum.
It goes against the current trend toward smaller and lighter equipment. Particularly, in the image forming apparatus in which the member to be charged is integrated in the cartridge, the weight of the cartridge is increased and the cost is increased.

Further, also in the sound insulation measure, there is a problem that the size of the apparatus is increased due to addition of a sound insulation member.

Therefore, the object of the third invention is that the charging noise can be suppressed to a low level without causing an increase in the size and weight of the apparatus, and even in an image forming apparatus with a fast process speed, pitch unevenness occurs in halftone. An object of the present invention is to provide a contact charging method capable of uniform charging without a charge.

By the way, conventionally, in order to suppress the generation of charging noise, it has been proposed to make the inside of the charging member hollow. An example thereof is shown in FIG.

That is, in the example shown in FIG. 24, as the material of the member 4-2 between the surface layer 4-3 of the charging member 4 and the core metal 4-1, a conductive sponge having an air bubble portion 4-4 is used. According to this, the charging noise can be suppressed to a low level.

However, when the charging member 4 is used, the deformation and vibration of the charging member 4 are increased, and the vibration waveform of the charging member 4 is largely deviated by a sine wave accordingly. Therefore, a charging sound including a large amount of higher harmonic components is generated with the charging member 4 and the contact portion between the charging member 4 and the image carrier 3 as a sound source.

D when a charging member 4 shown in FIG. 24 was used and an AC voltage of 450 Hz and 2.0 KV _PP was applied.
The vibration waveform of the charging member 4 on the dots is shown in FIG. Further, FIG. 26 shows frequency characteristics of the charging sound generated near the contact portion between the charging member 4 and the image carrier 3.

Therefore, an object of the fourth invention is to provide a contact charging device capable of suppressing the charging noise generated around the charging member and in the vicinity of the contact portion between the charging member and the image carrier. is there.

[0039]

[Means for Solving the Problems] To achieve the above object,
According to a first aspect of the present invention, a filling material made of a rigid body or an elastic body is internally provided inside an image carrier that is subjected to a charging process by contact with a charging member to which a voltage is applied, and when the gap with the filling material is 100 μm or more, the filling material is Is fixedly held on the inner surface of the image bearing body with a foaming agent or a sealing material.

The first aspect of the present invention includes at least an image carrier,
In a process cartridge that includes a charging member that comes into contact with the image carrier to charge the image carrier and is detachable with respect to the main body of the image forming apparatus, the image carrier is internally provided with a filler made of a rigid body or an elastic body, When the gap between the image carrier and the filling material is 100 μm or more, the filling material is fixed and held on the inner surface of the image bearing body by a foaming agent or a sealing material.

Further, the first invention is an image forming apparatus for executing image formation by applying an image forming process including a step of charging a charging member to an image carrier to charge the image carrier. The present invention is characterized in that a filling material made of a rigid body or an elastic material is internally provided in the carrier, and when the gap between the image carrier and the filler is 100 μm or more, the filler is fixed and held on the inner surface of the image carrier with a foaming agent or a sealing material. And

A second aspect of the invention is characterized in that, when the filling material having an elastic surface layer is press-fitted into the image bearing body, a lubricant is applied to the inner surface of the image bearing body to press-fit the filling material.

A third aspect of the present invention is a contact charging method in which a charging member to which a voltage is applied is brought into contact with a member to be charged to charge the member, and the voltage applied to the charging member is sinusoidal to a DC voltage. It is a voltage that superimposes an AC voltage that does not change,
Moreover, in the AC voltage, the amplitude of the fundamental wave when the voltage waveform is expanded into the Fourier series is 1 / the amplitude of the voltage waveform before expansion.
It is characterized by being 10 or less.

In a fourth aspect of the present invention, in a contact charging device for charging a charged member by applying a voltage-applied charging member to the charged member, a wall covering the periphery of the charging member is provided. .

[0045]

According to the first aspect of the present invention, a filling material composed of a rigid body or an elastic body is provided inside the image bearing member, and when the gap between the filling member and the image bearing member is 100 μm or more, the filling material is filled with a foaming agent or a sealing agent. Since the material is fixedly held on the inner surface of the image carrier, the vibration of the image carrier, which is the main cause of the charging noise, can be suppressed, and the frequency of the AC voltage applied to the charging member is set high. Also, the generation of charging noise can be suppressed.

According to the second aspect of the present invention, when the filling material having the elastic layer as the surface layer is press-fitted into the image bearing member, a lubricant is applied to the inner surface of the image bearing member and the filling material is press-fitted. Even if there are variations in characteristics, there will be no variations in pressure input, and
The filling material can be press-fitted with a low-voltage input, so that noise reduction and high image quality can be achieved.

According to the third aspect of the invention, the charging noise can be suppressed to a low level without increasing the size and weight of the device.
Even in an image forming apparatus having a high process speed, it is possible to uniformly charge with halftone without pitch unevenness.

According to the fourth aspect of the present invention, since the wall covering the periphery of the charging member functions as a soundproof wall, it is possible to suppress the charging noise generated around the charging member and near the contact portion between the charging member and the image carrier. it can.

[0049]

【Example】

[First Invention] An embodiment of the first invention will be described below with reference to the accompanying drawings.

FIG. 1 is a vertical sectional view of an image forming apparatus according to an embodiment of the present invention, and FIG. 2 is a perspective view of the same image forming apparatus when a process cartridge is inserted and removed.

The image forming apparatus according to this embodiment is a process cartridge removable laser beam printer using a transfer type electrophotographic process.

In FIG. 1, reference numeral 3 denotes a rotary drum type electrophotographic photosensitive member as an image bearing member (hereinafter referred to as a photosensitive drum).
Is. A filling material 3c is built in the photosensitive drum 3, and the photosensitive drum 3 is rotationally driven in the direction of the arrow (clockwise direction) at a predetermined peripheral speed (process speed).

Reference numeral 4 denotes a charging roller which is a charging member that is pressed against the photosensitive drum 3 with a predetermined pressing force. The charging roller 4 is composed of a conductive cored bar 4a made of SUS and a conductive elastic layer 4b made of urethane rubber containing carbon formed on the outer periphery thereof, and the outer diameter thereof is 12 mm.
Is set to, and is pressed against the surface of the photosensitive drum 3 by spring members (not shown) at both ends of the conductive cored bar 4a.
It rotates following the rotation of the photosensitive drum 3. Then, a predetermined voltage is applied to the conductive cored bar 4a from a power source device (not shown) so that the peripheral surface of the photosensitive drum 3 is charged by the charging roller 4a.
Thus, uniform charging treatment is performed by a direct method to a predetermined polarity and potential.

Thus, scanning exposure by the laser beam L modulated and output from the laser scanner unit 1 corresponding to the time-series electric digital pixel signal of the target image information is performed on the charged surface of the photosensitive drum 3. Done through mirror 2,
An electrostatic latent image corresponding to the exposure image information is formed on the peripheral surface of the photosensitive drum 3.

The electrostatic latent image is visualized as a toner image by the toner 6 of the developing device 5, and the toner image is fed between the photosensitive drum 3 and the transfer roller 7 at the position of the transfer roller 7. It is sequentially transferred to the surface of the transfer material 14. That is, the toner 6 is transferred to the transfer roller 7 by a power supply device (not shown).
By applying a transfer bias having a polarity opposite to that of the above and applying a charge of the opposite polarity to the back surface of the transfer material 14, the toner image on the photosensitive drum 3 is transferred to the transfer material 14.

Further, reference numeral 12 denotes a paper feed cassette which can be attached to and detached from the main body of the image forming apparatus, and a transfer material 14 in the cassette 12 is provided with a paper feed roller 13 which is driven to rotate based on a paper feed signal. Separation and feeding are performed one by one by a separation pad (not shown) provided so as to face the sheet feeding roller 13, guided along the upper and lower guides, and conveyed to the pair of registration rollers 15. The registration roller 15 is stopped until the transfer material 14 arrives, and the leading end of the transfer material 14 abuts against this, so that the skew of the transfer material 14 is corrected. Next, the registration roller 15 conveys the transfer material 14 to the transfer portion between the photosensitive drum 3 and the transfer roller 7 in synchronization with the front end of the toner image formed on the photosensitive drum 3.

The transfer material 14, which has received the toner image transferred at the transfer portion, is separated from the surface of the photosensitive drum 3 and is conveyed by the conveying guide 16.
Is conveyed to the fixing device 17. The fixing device 17 is
The toner image on the transfer material 14 is melted and fixed on the transfer material 14 by heat and pressure to form a recorded image. After the image is fixed, the transfer material 14 is discharged to the discharge tray 18 or 19 via the conveyance path selected by a flapper (not shown).

The surface of the photosensitive drum 3 after the toner image is transferred onto the transfer material 14 is cleaned by a cleaner 8 to remove adhered contaminants such as transfer residual toner, and is repeatedly subjected to image formation. It

By the way, in the printer according to the present embodiment, the process cartridge 1 which is detachable from the main body.
0 is loaded, and the process cartridge 10 is
The photosensitive drum 3, the charging roller 4, the developing device 5, and the cleaner 8 are housed in a common housing (exterior housing) 9 as a unit.

To attach and detach the process cartridge 10 to and from the printer body, as shown in FIG. 2, the front door 30 of the printer body is opened to open the inside of the printer body, and the guide 11 (see FIG. 1) on the printer body side is attached. This is done by engaging the process cartridge 10 and pushing or pulling it along the guide 11. And
When the process cartridge 10 is pushed sufficiently into the printer body, the process cartridge 10 is mechanically and electrically connected to the printer body side.

The process cartridge 10 may have at least the photosensitive drum 3 as an image carrier and the charging roller 4 as a charging member.

Here, details of the structure of the photosensitive drum 3 are shown in FIG.
And it demonstrates based on FIG. Incidentally, FIG. 3 shows the photosensitive drum 3.
FIG. 4 is an enlarged sectional view taken along line AA of FIG.

The photosensitive drum 3 according to this embodiment has a wall thickness of 1 m.
It is composed of a drum base 3a made of aluminum of m and an organic photosensitive layer 3b formed on the outer peripheral surface of the base 3a, and its outer diameter is 30 mm.

The filling 3c, which is a rigid body or an elastic body, is internally provided in the central portion of the photosensitive drum 3 in the axial direction. The material of the filler 3c may be a metal such as aluminum or brass, a ceramic such as cement or gypsum, or a rubber material such as natural rubber. Among these, productivity, workability, and weight effect, It may be appropriately selected in consideration of cost and the like.

The shape of the filler 3c is a cylinder or a cylinder, and the inner diameter of the photosensitive drum 3 is Φ2, for example.
In the case of 8.5H8, the filler 3c is inserted into the photosensitive drum 3 with its outer diameter reduced by 100 μ or more. Photosensitive drum 3
When the gap D of the filling material 3c and the filling material 3c is larger than at least 100 μ, the adhesion of the filling material 3c to the photosensitive drum 3 is enhanced by using a foam or a sealing material as a means for filling the gap D and a fixing means. Thing 3c
Is held in the photosensitive drum 3 to increase the weight itself and the rigidity of the photosensitive drum 3.

As a foaming means, a foaming sheet may be wound around the filling 3c in advance, and the sheet may be filled in the photosensitive drum 3 and heated at about 100 ° C. for foaming. The foamable substance may be injected after inserting into the photosensitive drum 3. On the other hand, as a sealing means, a sealing material may be injected until the gap D can be filled.

Next, Tables 1 and 2 show the results of experiments by the present inventors regarding charging noise. Table 1 shows the relationship between the weight of the filling and the sound pressure (sound generated by charging), and Table 2 shows the relationship between the photosensitive drum and the gap (gap) when the filling is inserted and the sound pressure.

[0068]

[Table 1] Filling material for photosensitive drum; Aluminum rod L; Filling length (aluminum rod length) (mm) D; Gap amount (μm) ΔdB; Increase in noise level (dB)

[0069]

[Table 2] Here, the relationship between the weight of the filler and the sound pressure (sound generated by charging) shown in Table 1 will be described.

As an experimental method, the background noise is 30 dB (A).
Laser printer "LBP-A404" in the anechoic chamber
The process cartridge containing the charging roller for Canon (manufactured by Canon Inc.) is installed and installed in the idle rotation machine, and the normal sound level meter "NL-0
2 "(manufactured by Rion Co., Ltd.) is installed.

The printer is modified so that only the photosensitive drum can be freely rotationally driven from the outside, and a desired voltage can be applied to the charging roller by an external high voltage power source. Then, when the noise level XdB (A) when the photosensitive drum is simply driven to rotate and the predetermined alternating voltage with the frequency thereof changed is applied to the charging roller in contact with the noise level while rotating the photosensitive drum. The noise level YdB (A) is measured, and the difference Δ = (Y−X) dB (A) between them is calculated and compared as an increase in the noise level due to the charging sound.

At this time, the peripheral speed of the photosensitive drum is 50.
mm / sec, the peak-to-peak voltage of the AC voltage applied to the charging roller was 2000V.

According to Table 1, it is understood that, when an experiment is conducted using a filler of the same material, the effect of reducing the sound pressure is great if the contact length and the weight increase. According to the study by the present inventors, the increase Δ of the noise level due to the charging noise is 4 dB (A).
It has been confirmed that the noise level is practically no problem if it is below.

Next, the relationship between the sound pressure and the gap (gap) at the time of inserting the photosensitive drum and the filler shown in Table 2 will be described.

The experiment method was basically the same as the above experiment, and an adhesive (for example, a cyanoacrylate type or an epoxy resin type) was used as a fixing method for both. From this, it was found that if the gap D is 100 μm or less, there is no problem in practical use even if the adhesive is fixed with the above-mentioned adhesive, but if the gap D is 100 μm or more, the adhesive has no effect. There wasn't.

Therefore, Table 3 shows the experimental results when a foaming agent or a sealing material was used so as to fill the gap D between them.

[0077]

[Table 3] According to the results shown in Table 3, a foaming agent or a sealing material is used as a fixing means to improve the adhesiveness with the photosensitive drum.
As a result, it was found that the effect was remarkably exhibited, and the level could be improved to a level where there was no practical problem. However, the condition for satisfying this result is that the drum weight obtained by the above result is satisfied, and a method of manufacturing such a photosensitive drum is as follows. After the organic photosensitive layer is formed and dried on the outer peripheral surface, the filler may be inserted and adhered. Therefore, for example, when the organic photosensitive layer is formed and the drying process is lengthened as the heat capacity of the photosensitive drum base increases. It does not cause extreme deterioration of productivity.

The shape of the filling material is not limited to the cylindrical system and may be a non-circular shape. Also regarding these, the weight and the like must satisfy the above, and the maximum gap with the photosensitive drum may be 100 μm or more. [Second Invention] An embodiment of the second invention will be described below with reference to the accompanying drawings.

<First Embodiment> As shown in FIG. 5, the diameter is 2
2mm aluminum rod 3f and EPDM rubber (JI
SA hardness 50 °) 3e is integrally molded to have an outer diameter of 28.
A rubber roller 3A having a length of 66 mm, a length of 70 mm and a surface roughness R _Z = 19 μm was produced.

Next, 3 g of a silicone polymer having an average particle diameter of 12 μm is applied to a portion from the inner wall side end portion of the photosensitive member 3 having an outer diameter of 30 mm and an inner diameter of 28.5 mm to 12 mm, which is a filler. The rubber roller 3A was pressed into the photoconductor 3. The pressure input at that time was 55 kgf, and the straightness of the photoconductor 3 was 22 μm.

After that, gear flanges (not shown) are adhered to both ends of the photoconductor 3 and the photoconductor 3 is attached to the position of the photoconductor drum used in the LBP-A404 (page printer manufactured by Canon Inc.), and then an AC voltage of 2 kV is applied as a bias. The vibration sound when a frequency of 500 Hz and a DC voltage of -700 V was applied was measured in an anechoic chamber according to the sixth item of ISO-7779, and the vibration sound was as good as 51 dB.
When the initial image was confirmed, a good image was obtained. Results are shown in FIG.

<Comparative Example 1> The same procedure as in Example 1 was carried out except that the filler was not press-fitted inside the photosensitive member. The initial image was good, but the vibration noise was very large at 71 dB. , There was a problem in practice. The straightness of the photoconductor at this time was 15 μm. Results are shown in FIG.

<Second Embodiment> Instead of an aluminum rod having a diameter of 22 mm and EPDM rubber (JIS A hardness of 50 °), a brass rod having a diameter of 10 mm and a CR rubber (J
ISA hardness 50 °) with an outer diameter of 28.70 mm, a length of 60 mm and a surface roughness R _Z = 9 μm, and an average particle size of 20 μm instead of the silicone polymer.
When the same procedure as in Example 1 was carried out except that PVDF of No. 3 was used, the pressure input was 69 kgf and the straightness was 35 μm.
Met. The vibration sound at this time is as good as 51 dB,
In addition, a good image was obtained by checking the initial image. Results are shown in FIG.

<Comparative Example 2> The procedure of Example 1 was repeated except that the silicone polymer was not applied to the inside of the photoconductor, and the surface roughness R _{Z was} 21 μm and the pressure input was 15.
It was 2 kgf and the straightness was 15 μm.

The vibration sound at this time was as good as 53 dB, but when the initial image was confirmed, it was found that there was partial unevenness in density, which was a problem in practical use. Results are shown in FIG.

<Third Example> The same as the first example except that 70 ° EPDM rubber was used instead of JISA hardness of 50 ° and graphite having a surface particle size of 3 μm was used instead of the silicone polymer. When performed in the same manner, the surface roughness R _Z = 16 μm, the pressure input is 63 kgf, and the straightness is 30 μ.
It was m. The vibration sound at this time was as good as 51 dB, and a good image was obtained by checking the initial image. Results are shown in FIG.

<Fourth Embodiment> An outer diameter of 28.73 mm, a length of 200 mm, and a surface roughness R _Z = 15 which is made of EPDM rubber (JIS A hardness of 50 °) only without using a metal shaft.
The same operation as in Example 1 was carried out except that a rubber roller of μm was used as the filling material, and the pressure input was 80 kg.
f, the straightness was 37 μm. The vibration sound at this time is 5
It was as good as 8 dB, and the initial image was also good. Results are shown in FIG. [Third Invention] An embodiment of the third invention will be described below with reference to the accompanying drawings.

<Embodiment 1> FIG. 8 is a schematic configuration diagram of a main part of an image forming apparatus using a contact charging device according to the present invention.

In the figure, 3 is a photosensitive drum as an image bearing member, which is an OP having a thickness of 25 μm and a dielectric constant of about 3.
The C photosensitive layer 3a is formed on the conductive drum substrate 3b made of A1, which is in the arrow direction (clockwise direction) in the figure.
It is driven to rotate at a predetermined process speed.
In this embodiment, the image carrier is a drum type, but it may be a rotating belt type or the like. In any case, seamless ones can of course be used, and those with seams can also be used if each copying step is performed by obtaining a synchronizing signal.

Reference numeral 2 is a short focus lens array as an exposure means for forming a latent image on the photosensitive drum 3, 5 is a developing device, 7 is a transfer roller as a transfer means, and 15 is a paper feeding unit (not shown). A timing roller (registration roller) for feeding the transfer material 14 conveyed sheet by sheet in synchronism with the rotation of the photosensitive drum 3 and feeding it between the photosensitive drum 3 and the transfer roller 7 (transfer portion); Transfer roller 7
It is a transfer guide disposed between and.

Reference numeral 21 denotes a conveying portion for introducing the transfer material 14 having undergone the image transfer between the photosensitive drum 3 and the transfer roller 7 to a fixing device (not shown), and 8 denotes the residual material on the photosensitive drum 3 after the image transfer. A cleaning device for removing toner and the like, 8a is a cleaning blade, and 4 is a charging roller as a charging member that contacts the photosensitive drum 3 after cleaning to uniformly charge the photosensitive drum 3.

In the image forming apparatus according to this embodiment,
The four process devices including the photosensitive drum 3, the developing device 5, the cleaning device 8, and the charging roller 4 are collectively assembled as a process cartridge 10 having a predetermined positional relationship with each other. The cartridge 10 is an image forming apparatus. It can be installed by inserting it in the main body along a support rail (not shown) in the direction perpendicular to the paper surface of FIG.
On the contrary, it can be freely removed from the device body.

By inserting and mounting the process cartridge 10 in the apparatus main body, the apparatus main body side and the process cartridge 10 side are mechanically and electrically connected to each other, whereby the image forming apparatus becomes operable.

By the way, the charging roller 4 is constructed by bonding a conductive rubber to a metal cored bar, and a voltage is applied from a power source E to the cored bar. Although the roller-shaped member (charging roller 4) is used as the charging member in this embodiment, it is needless to say that a blade-shaped member can be used.

(Experiment) In the image forming apparatus shown in FIG. 8, the noise level of the main body was measured by changing the voltage waveform. The used waveform is shown in FIG. In FIG. 7, the AC voltage waveform y is represented by the following equation.

[0096]

[Equation 4] Here, A: amplitude X: positive number Here, this voltage waveform y is a symmetrical wave and is an odd function, that is, y (θ) = − y (−θ) = − y (θ + π) =
There is a property of y (π−θ). Using this property,
The Fourier series of y (θ) can be expressed as follows.

[0097]

[Equation 5] Since y (θ) is given by the equation (1), the coefficient b _{2m + 1} of the Fourier series of y (θ) is expressed as follows by substituting the equation (1) into the equation (3). .

[0098]

[Equation 6]

[0099]

[Equation 7] 1) When X ≠ 2m + 1:

[0100]

[Equation 8] 2) When X ≠ 2m + 1:

[0101]

[Equation 9] In this experiment, the value of X was three kinds of X = 5, 10, and 20, and the noise level was measured for a total of four kinds of waveforms by adding a sine wave (corresponding to X = 1) as a conventional example. .
The waveforms at this time are y _{X = 5} , y _{X = 10} , y _{X = 20,} and the sin wave of the conventional example is y _{X = 1} .

The amplitude (coefficient) of the fundamental frequency of y _{X = 5} is expressed as b _{1X = 5} , and the amplitude (coefficient) of the triple frequency is expressed as b _{3X = 5} . The value of the coefficient of the Fourier series is calculated for each of the four types of waveforms. The results are shown in Table 1. In Table 1, the fundamental frequency is shown for frequency components of 3 times and 5 times.

[0103]

[Table 1] The conditions for noise measurement are as shown below.

(Bias condition) Frequency: 400H _Z Peak-to-peak voltage: 2KV (A = 2000V) DC voltage: -600V Arbitrary waveform generator, AG1200 (manufactured by Yokogawa Electric Corp.) is used to create a waveform, and an amplifier is used. Amplified 2000 times (Charging roller condition) Outer diameter: φ12 Core metal diameter: φ6 Roller resistance: 5 × 10 ⁶ Ω Roller hardness: 60 ° Pressurizing force: 1kgf on both ends of core metal (Charging sound measurement condition) Measurement position: Front of main body From 1m main body: Non-paper feed, drum rotation (process speed
50 mm / sec) Measuring instrument: Sound level meter (NL-02) manufactured by Rion Co. A characteristic Laeq (integrated value for 1 minute) Dark noise: 40 dB The measurement results are shown in Table 2.

[0105]

[Table 2] As is clear from Table 2, as compared with the noise level of y _{X = 1} (sine wave), that of waveform y _{X = 5} is larger, that of waveform y _{X = 10} is almost the same, that of waveform y _{X = 20} is smaller. Has become.

FIG. 9 shows a graph in which the horizontal axis (logarithmic scale) shows the amplitude of the fundamental frequency in Table 1 and the vertical axis shows the noise level in Table 2.

In FIG. 9, except for y _{X = 1} (sine wave), three waveforms of y _{X = 5} , y _{X = 10} and y _{X = 20} are
It can be seen that the noise level decreases in proportion to the logarithm of the amplitude of the fundamental frequency.

Further, in order to make the noise level smaller than y _{X = 1} (sinusoidal wave), the amplitude of the fundamental frequency is 1 / of the original amplitude.
It turns out that it should be about 10.

Since y _{X = 20 according} to the present embodiment has a fundamental frequency amplitude of 0.064, which is 1/10 or less, it is possible to lower the noise level than y _{X = 1} (sine wave). It was

Although the amplitude of the fundamental frequency at y _{X = 5} is as small as 0.252 times as large as that of y _{X = 1} (sinusoidal wave),
The reason why the noise level is large is that y _{X = 1} (sine wave) has 0 or more frequency components of 3 times or more, while y _{X = 5} has a frequency component of 3 times or more of 0.2 times level. It has amplitude, and it is considered that this higher-order frequency component resulted in raising the noise level.

Further, when the image was evaluated with a waveform of y _{X = 20,} a good halftone image equivalent to the conventional triangular wave and sin wave was obtained without any uneven charging. And
Half-tone pitch has a process speed of 50 mm /
Since in sec, for the frequency 400H _Z, 0.1
The image quality was 25 mm, and the image quality was not noticeable to the naked eye and the image quality was sufficient.

<Embodiments 2, 3, 4> FIG. 10 shows waveforms of another embodiment. The waveform f (θ) is represented by the following equation.

[0113]

[Equation 10] Here, A: amplitude X: positive number Here, this voltage waveform f (θ) is a symmetrical wave, and
Since it is an odd function, the Fourier series of f (θ) can be expressed as follows.

[0114]

[Equation 11] Since f (θ) is given by the equation (4), the coefficient b ′ _{2m + 1} of the Fourier series of f (θ) is expressed by the following equation by substituting the equation (4) into the equation (6). .

[0115]

[Equation 12] In this embodiment, the value of X is 3 of X = 10, 20, 40.
The noise level was measured for a total of four types of waveforms by adding a triangular wave (corresponding to X = 1) as a conventional example. The waveforms at this time are f _{X = 10} , f _{X = 20} , and f _{X = 40, respectively.}
Also, the sin wave of the conventional example is set as f _{X = 1} .

Further, the amplitude (coefficient) of the fundamental frequency of f _{X = 10} is expressed as b ′ _{1X = 10} , and the amplitude (coefficient) of the triple frequency is expressed as b ′ _{3X = 10} . For each of the four types of waveform,
The value of the coefficient of the Fourier series is calculated. The results are shown in Table 3.
Shown in. In Table 3, the fundamental frequency is shown for frequency components of 3 times and 5 times.

[0117]

[Table 3] The conditions for noise measurement are as shown below.

(Bias conditions) Frequency: 400H _Z Peak-to-peak voltage: 2KV (A = 2000V) DC voltage: -600V Arbitrary waveform generator, AG1200 (made by Yokogawa Electric Corp.) was used to create a waveform, and an amplifier was used. Amplified 2000 times (Charging roller condition) Outer diameter: φ12 Core metal diameter: φ6 Roller resistance: 5 × 10 ⁶ Ω Roller hardness: 60 ° Pressurizing force: 1kgf on both ends of core metal (Charging sound measurement condition) Measurement position: Front of main body From 1m main body: Non-paper feed, drum rotation (process speed
50 mm / sec) Measuring instrument: Sound level meter (NL-02) manufactured by Rion Co. A characteristic Laeq (integrated value for 1 minute) Dark noise: 40 dB Table 4 shows the measurement results.

[0119]

[Table 4] As is clear from Table 4, as compared with the noise level of fX _{= 1} (triangular wave), that of the waveform fX _{= 5} is larger, that of the waveform fX _{= 10} is almost the same, that of the waveform fX _{= 20} is smaller. ing.

FIG. 11 is a graph in which the amplitude of the fundamental frequency in Table 3 is plotted on the horizontal axis (logarithmic scale) and the noise level in Table 2 is plotted on the vertical axis.

In FIG. 11, except for f _{X = 1} (ref), three waveforms of f _{X = 10} , f _{X = 20} , and f _{X = 40} are as follows:
It can be seen that the noise level decreases in proportion to the logarithm of the amplitude of the fundamental frequency.

Further, it can be seen that the amplitude of the fundamental frequency may be set to about 1/10 of the original amplitude in order to make the noise level smaller than ref.

Since f _{X = 40} of the second embodiment has a fundamental frequency amplitude of 0.025, which is 1/10 or less, it is possible to lower the noise level than the ref triangular wave. Similarly, since the amplitude is 0.05 for f _{X = 20} of the third embodiment and 0.025 for f _{X = 40} of the fourth embodiment, the noise level is lower than that of the ref triangular wave. It became possible to do.

Further, when image evaluation was performed using the waveforms of f _{X = 10} , f _{X = 20} , and f _{X = 40,} a halftone image equivalent to a conventional triangular wave or sin wave was obtained, and a good image without charge unevenness was obtained. was gotten. In addition, the pitch of the half-tone because the process speed is at 50mm / sec, is 0.125mm with respect to the frequency 400H _Z, to the naked eye was of sufficient quality without noticeable almost. [Fourth Invention] An embodiment of the fourth invention will be described below with reference to the accompanying drawings.

<First Embodiment> FIG. 12 is a block diagram of a contact charging device according to the first embodiment of the present invention.

In the figure, 3 is a photosensitive drum which is an image bearing member, 4 is a charging roller which is a charging member, and the charging roller 4 is an AC bias (2.0K) from an external power source (not shown).
V _PP, 450H _Z) core metal 4-1 for applying a surface layer member 4-3 is composed of a conductive sponge 4-2 provided between the core metal 4-1 and the surface layer member 4-3, A plurality of air bubbles 4-4 are formed on the conductive sponge 4-2.

By the way, in this embodiment, the charging roller 4 is covered with the soundproof wall 31. The soundproof wall 31 is provided over the lengthwise direction of the charging roller 4 (the direction perpendicular to the paper surface of FIG. 12). It covers the periphery of the roller 4.

As the material of the soundproof wall 31, a sound insulating material,
A soundproof material such as a sound absorbing material is most desirable, and the soundproof wall 31
In order to prevent the secondary solid sound from being generated, it is also preferable that the material is a vibration damping material or a vibration damping material. However, it is necessary to select the material of the soundproof wall suitable for the system in consideration of the resonance with the soundproof material due to the frequency of the charging sound and the necessary transmission loss property in the charging system. In this example, a transmission loss of 15 dB was obtained by using a soundproof wall made of a modified polyphenylene oxide resin having a thickness of 1 mm.

The position of the sound barrier is closer to the sound source,
This is desirable because it is possible to suppress an increase in sound pressure due to the reflected sound or the induced secondary solid sound, and the area of the rod sound wall can be small. Therefore, as shown in FIG. 13, the soundproof wall 31 may be shaped so as to cover the entire charging roller 4.

<Second Embodiment> FIG. 14 is a block diagram of a contact charging device according to the second embodiment.

In this embodiment, the ozone filter 32 is provided near the contact portion of the soundproof wall 31 between the charging roller 4 and the photosensitive drum 3.

Since the contact charging method has a lower charging voltage than the conventional corona charging method, the amount of ozone generated is very small. However, when the vicinity of the contact portion between the charging roller 4 and the photosensitive drum 3 is sealed, the ozone is not generated. Accumulation may cause unnecessary images.

Therefore, in this embodiment, the ozone filter 32 is provided to remove the generated ozone.
Although various kinds of ozone filters 32 can be considered, in the present embodiment, the inner surface of the soundproof wall 31 is roughened to increase the surface area, and activated carbon is attached to this surface to adsorb ozone.

If the soundproof wall 11 has a two-stage structure as shown in FIG. 15, the air flow in the vicinity of the contact portion between the photosensitive drum 1 and the charging roller 2 can be made as indicated by arrow e. Therefore, the accumulation of ozone does not occur, and it is possible to block the sound that has a strong straight traveling characteristic.

<Third Embodiment> FIG. 16 is a block diagram of a contact charging device according to the third embodiment.

In the present embodiment, the soundproof wall 31 has the elastic blade 33 over the entire length in the vicinity of the photosensitive drum 3 at the tip thereof, and the elastic blade 33 is provided.
Is in contact with the surface of the photosensitive drum 3. As a result, it is possible to realize complete sealing around the charging roller 4, which is impossible with a rigid soundproof wall. In this embodiment, the elastic blade 33 is made of urethane rubber having a thickness of 2 mm.

Further, as shown in FIG. 17, if the soundproof wall 31 has a double structure by utilizing the curved surface of the photosensitive drum 3, it is possible to virtually completely shut off a sound having a strong straight traveling property.

<Fourth Embodiment> FIG. 18 is a block diagram of a contact charging device according to a fourth embodiment.

In this embodiment, the soundproof wall 31 has a large number of pyramid-shaped protrusions 34 on its inner surface.
As a result, as shown in FIG. 19, the sound F coming toward the soundproof wall 31 is repeatedly reflected and attenuated by the projection 34.
In addition, since the soundproof wall 31 has many protrusions 34,
The soundproof wall 31 is less likely to resonate, and the generation of secondary solid sound can be prevented.

Further, as shown in FIG. 20, by alternately providing the protrusions 34 and the sound absorbing material 35 on the inner surface of the soundproof wall 31, the sound F reflected by the protrusions 34 is absorbed by the sound absorbing material 35 and disappears. Therefore, more effective soundproofing can be performed.

<Fifth Embodiment> FIGS. 21 and 22 are views showing the arrangement of a contact charging device according to the fifth embodiment.

In the example shown in FIG. 21, the charging blade 36 is used as the charging member, and the periphery thereof is covered with the soundproof wall 31. Further, in the example shown in FIG. 22, the charging brush 37 is used as the charging member, and the periphery thereof is covered with the soundproof wall 31.

In any of the above cases, the main sound source of the generated charging sound is not the photosensitive drum 3 but the vicinity of the charging blade 36 or the charging brush 37, which is a charging member,
Therefore, also in the present embodiment, it is possible to suppress the charging noise by covering the charging blade 36 or the charging brush 37 with the soundproof wall 31.

[0144]

As is apparent from the above description, according to the first aspect of the present invention, the image carrier is internally provided with a filler made of a rigid body or an elastic body, and the gap between the filler and the image carrier is 100 μm.
When the value is m or more, the filling is fixedly held on the inner surface of the image carrier with a foaming agent or a sealing material, so that the vibration of the image carrier, which is the main cause of the charging noise, can be suppressed and applied to the charging member. Even when the frequency of the AC voltage is set high, the generation of charging noise can be suppressed.

According to the second aspect of the present invention, when the filling material having the elastic layer as the surface layer is press-fitted into the image bearing member, a lubricant is applied to the inner surface of the image bearing member and the filling material is press-fitted. Even if there are variations in characteristics, there will be no variations in pressure input, and
The filling material can be press-fitted with a low-voltage input, so that noise reduction and high image quality can be achieved.

According to the third aspect of the invention, the charging noise can be suppressed to a low level without increasing the size and weight of the device.
Even in an image forming apparatus having a high process speed, it is possible to uniformly charge with halftone without pitch unevenness.

According to the fourth aspect of the present invention, since the wall covering the periphery of the charging member functions as a soundproof wall, it is possible to suppress the charging noise generated around the charging member and near the contact portion between the charging member and the image carrier. it can.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of an image forming apparatus according to a first invention.

FIG. 2 is a perspective view of the image forming apparatus according to the first aspect of the invention when the process cartridge is inserted and removed.

FIG. 3 is a vertical cross-sectional view of a photosensitive drum of the image forming apparatus according to the first invention.

FIG. 4 is an enlarged sectional view taken along line AA of FIG.

FIG. 5 is a cross-sectional view of a photoconductor manufactured according to a second invention.

FIG. 6 is a diagram showing test results in the second invention.

FIG. 7 is a diagram showing a voltage waveform used in an experiment in the third invention.

FIG. 8 is a schematic configuration diagram of a main part of an image forming apparatus using a contact charging device according to a third invention.

FIG. 9 is a diagram showing the relationship between the amplitude of the fundamental frequency and the noise level.

FIG. 10 is a diagram showing bias waveforms in Examples 2 to 4 of the third invention.

FIG. 11 is a diagram showing the relationship between the amplitude of the fundamental frequency and the noise level in Examples 2 to 4 of the third invention.

FIG. 12 is a configuration diagram of a contact charging device according to a first embodiment of the fourth invention.

FIG. 13 is a configuration diagram showing a modification of the contact charging device according to the first exemplary embodiment of the fourth invention.

FIG. 14 is a configuration diagram of a contact charging device according to a second embodiment of the fourth invention.

FIG. 15 is a configuration diagram showing a modified example of the contact charging device according to the second exemplary embodiment of the fourth invention.

FIG. 16 is a configuration diagram of a contact charging device according to a third embodiment of the fourth invention.

FIG. 17 is a configuration diagram showing a modification of the contact charging device according to the third exemplary embodiment of the fourth invention.

FIG. 18 is a configuration diagram of a contact charging device according to a fourth embodiment of the fourth invention.

FIG. 19 is a diagram showing reflection and attenuation of sound on a soundproof wall (when a protrusion is provided).

FIG. 20 is a view showing reflection and attenuation of sound in the soundproof wall (when protrusions and sound absorbing materials are provided alternately).

FIG. 21 is a configuration diagram of a contact charging device according to a fifth embodiment of the fourth invention.

FIG. 22 is a configuration diagram of a contact charging device according to a fifth embodiment of the fourth invention.

FIG. 23 is a configuration diagram of a conventional contact charging device.

FIG. 24 is a configuration diagram of a conventional contact charging device using a hollow charging member.

FIG. 25 is a diagram showing a vibration waveform of the hollow charging member shown in FIG. 24.

FIG. 26 is a frequency characteristic diagram of a charging sound.

[Explanation of symbols]

 3 Photosensitive Drum, Photoreceptor (Image Carrier) 3c Filler 3g Silicone Polymer (Lubricant) 4 Charging Roller (Charging Member) 10 Process Cartridge 31 Soundproof Wall (Wall) 32 Ozone Filter 33 Elastic Blade (Elastic Body) 34 Projection 36 Charging Blade (Charging Member) 37 Charging Brush (Charging Member)

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Yuji Ishihara 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Hiroshi Koyama 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon (72) Inventor Masahiro Goto 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Manabu Takano 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Reihisa Hoshika, 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) In-house Yasushi Shimizu, 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (14)

[Claims] 1. An image carrier, which is subjected to a charging process by contact with a charging member to which a voltage is applied, and internally has a filling material made of a rigid body or an elastic body, and a gap between the filling material and the filling material is 1
An image carrier characterized in that the filler is fixed and held by a foaming agent or a sealing material when the thickness is 00 μm or more. 2. A process cartridge which includes at least an image carrier and a charging member for contacting the image carrier and charging the image carrier, and the process cartridge being detachable from the main body of the image forming apparatus. Alternatively, the process cartridge is characterized in that a filling material made of an elastic material is internally provided, and when the gap between the image bearing member and the filling material is 100 μm or more, the filling material is fixed and held on the inner surface of the image bearing member by a foaming agent or a sealing material. . 3. An image forming apparatus for performing image formation by applying an image forming process including a step of charging a charging member to an image bearing member to charge the image bearing member. An image forming apparatus characterized in that a filling material made of an elastic material is provided inside, and when the gap between the image bearing member and the filling material is 100 μm or more, the filling material is fixedly held on the inner surface of the image bearing member by a foaming agent or a sealing material. . 4. A method of manufacturing an image carrier, wherein when a filler having an elastic surface layer is press-fitted into the image carrier, a lubricant is applied to the inner surface of the image carrier to press-fit the filler. 5. The method for manufacturing an image bearing member according to claim 4, wherein the lubricant is a siloxane compound. 6. The method of manufacturing an image bearing member according to claim 4, wherein the lubricant is a solid lubricant. 7. The method for producing an image bearing member according to claim 6, wherein the solid lubricant is a fluorine compound. 8. The method of manufacturing an image bearing member according to claim 6, wherein the solid lubricant is a layered lattice structure material. 9. A contact charging method in which a charging member to which a voltage is applied is brought into contact with a member to be charged to charge the member to be charged, and the voltage applied to the charging member is an alternating current that is not a sinusoidal change in a DC voltage. A contact voltage, which is a voltage obtained by superimposing a voltage, and in which the amplitude of the fundamental wave when the voltage waveform is expanded into a Fourier series is 1/10 or less of the amplitude of the voltage waveform before expansion. Charging method. 10. A contact charging device for charging a charged member by bringing a charging member to which a voltage is applied into contact with the charged member, wherein a wall covering the periphery of the charging member is provided. . 11. The contact charging device according to claim 10, wherein an ozone filter is provided on at least a part of the wall. 12. The contact charging device according to claim 10, wherein a ventilation opening is provided on at least a part of the wall. 13. The elastic member is provided on the wall so as to come into contact with the image carrier along the longitudinal direction.
The contact charging device described. 14. The contact charging device according to claim 10, wherein a protrusion is provided on a surface of the wall facing the charging member.