JPH06282147A - Electrofying member and image forming device - Google Patents

Abstract

PURPOSE:To obtain an electrifying member having uniform resistance and stable resistance without influenced by environmental changes by incorporating electron conductive particles and ion conductive particles into the material. CONSTITUTION:When the voltage applied from the power source 3 to a conductive elastic roller 1 is changed and the current in the conductive elastic roller 1 is measured with an ammeter, it is found that the current in the roller has dependance on the voltage applied and that the resistance of the roller changes depending on the voltage applied. Then, ion conductive particles and electron conductive particles are incorporated into the conductive elastic roller. As for the electron conductive particles, carbon, tin oxide, indium tin, antimony tin, etc., are used. The ion conductive particles are lithium compds. such as LiO2, LiF, Li2CO3 or mixture of these, or ionic crystals such as beta-Al2O3, phosphorus tungstic acid, phophomolybdic acid, uranyl hydrogenphosphate, (CH3)4NOH.5H2O (TMAH5), and NaHSO4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charging member and an image forming apparatus equipped with this charging member.

[0002]

2. Description of the Related Art Conventionally, as a charging device used in an electrophotographic image forming apparatus, a corona charging device which applies a high voltage to a metal wire and charges the generated corona is often used. However, the corona charging method requires a high voltage power source of 5 to 8 kV DC, which is highly dangerous. Also it generates harmful ozone and NO _X, etc. on the human body during corona generating, wire these corona products -
However, there is a problem that image defects occur due to stains on the surface of the photoconductor and degeneration of the surface of the photoconductor.

On the other hand, the contact charging device has a merit that the voltage to be applied is lower than that of the corona charging device and the generation of ozone harmful to the human body is low. As a method by contact charging, a method using a roller, a blade, a brush, a brush roller in which the brush is roller-shaped, a web, a wire, etc. is known (Japanese Patent Laid-Open No. 147756/1985). JP-A-3-174562).

Among these contact charging systems, rollers and blades have a structure in which a conductive elastic body is formed around a conductive substrate and are installed in contact with the surface of the body to be charged. Since the body to be charged rotates, the charging member needs to have elasticity so as not to damage the surface of the body to be charged, and the charging member itself is required to have abrasion resistance.

As can be seen from the phenomenon of light emission on the surface of the charging member and the generation of a small amount of ozone, the member to be charged is charged by discharge. Therefore, one of the characteristics required of the charging member is the stability of the electric resistance value of the charging member. That is,
The voltage drop from the conductive substrate to which a high voltage is applied to the surface of the conductive elastic body that contacts the charged body is affected by the resistance value of the elastic body in the thickness direction. Also, when the resistance value of the elastic body changes depending on the environment, the potential characteristic of the surface of the charging member changes, and as a result, the surface charging potential of the charged body changes.

Further, if the resistance value from the conductive substrate to the conductive elastic body is low, a high electric field is applied to the photosensitive member, which is the member to be charged, and the photosensitive member is destroyed. On the contrary, if the resistance value from the conductive substrate to the conductive elastic body is high, a higher applied voltage is required at the start of discharge, and sufficient charging cannot be performed.

As described above, the charging member composed of rollers and blades has elasticity, is resistant to abrasion, has a uniform and optimum electric resistance value, and is affected by the environment. And must be stable.

In order to obtain a charging member having an optimum resistance value,
It is necessary to disperse a large amount of conductive particles such as carbon in an elastic body such as rubber, which increases rubber hardness. When the rubber hardness is high, there is a problem that the charged body is damaged.

As the conductive elastic body, urethane rubber or silicone rubber in which a conductive filler is dispersed is conventionally known. Carbon, graphite, metal powder and the like are known as the conductive fillers used, but there is a problem that it is difficult to make the dispersibility uniform and reduce the variation in the resistance value.

On the other hand, in a charging member using a brush made of fibers in which conductive particles are dispersed, it is difficult to improve the uniformity of the resistance value in the fibers more than a roller or blade. If the resistance value in the fiber is not uniform, there is a problem that vertical stripes due to uneven charging occur as image defects.

[0011]

As described above, conductive fillers such as carbon, graphite, and metal powder have been conventionally used as elastic bodies such as urethane rubber and silicone rubber, and fibers such as polyester and rayon. However, it is difficult to uniformly disperse the conductive filler, and therefore it is difficult to obtain a conductive charging member having a uniform resistance value. there were.

The present invention has been made to eliminate the above drawbacks, and provides a charging member and an image forming apparatus which have a uniform resistance value and are stable without changing the resistance value due to the environment. To aim.

[0013]

SUMMARY OF THE INVENTION The present invention is a charging member that is placed in contact with or in proximity to a member to be charged and charges the member to be charged, and comprises ion conductive particles and electron conductive particles. Provided is a charging member characterized by containing.

Further, the present invention comprises a charging member for charging the image bearing member, a means for exposing the charged image bearing member to form an electrostatic latent image, and the latent image forming means. Developing means for developing the electrostatic latent image, transfer means for transferring the developer image developed by the developing means onto the image forming medium, and the developer image transferred by the transferring means for receiving the image. An image forming apparatus is provided, which comprises: a unit for fixing onto a forming medium, wherein the charging member contains ion conductive particles and electron conductive particles.

[0015]

The charging member of the present invention contains ion conductive particles and electron conductive particles in order to impart conductivity. A charging member in which electron conductive particles are dispersed is conventionally known,
Electron conductive particles such as carbon have poor dispersibility and cannot obtain uniform resistance, which causes a problem that uneven charging occurs.

On the other hand, it is possible to disperse ion conductive particles having a smaller particle size and good dispersibility than the electron conductive particles instead of the electron conductive particles. However, there is a problem that the resistance value of the charging member is greatly affected by the environment and changes with the environment such as temperature and humidity. It is considered that this is because, for example, the degree of contraction of the elastic body (the degree of entanglement of molecular chains) changes due to a change in temperature, and the mobility of ions also changes.

Therefore, in the present invention, the electron conductive particles are dispersed in order to obtain a stable predetermined resistance value irrespective of environmental changes, and in order to obtain a uniform resistance, the ion conductive particles are combined with the ion conductive particles. By dispersing the conductive particles, the problems of the ion conductive particles and the electron conductive particles are mutually complemented, and it becomes possible to provide a charging member having uniform and stable resistance.

[0018]

EXAMPLES First, the image forming apparatus of the present invention will be described. (Example 1)

The copying machine shown in FIG. 1 is constructed as follows. That is, a drum-shaped photosensitive member 103 is provided as an image carrier rotatably in a direction indicated by an arrow a in the center of a copying machine main body 101 (hereinafter referred to as the main body 101). The photoconductor 103 has a photoconductive layer on its surface.
The following devices are fixed around the photoconductor 103 along the rotation direction thereof.

That is, the charging device 105 having the charging member of the present invention for uniformly charging the surface of the photoconductor 103, and the charged photoconductor 103 above the photoconductor 103 in the rotational direction of the charging device 105. A slit glass 107 for slit exposure using the original image as a light source is provided above. Further, the photoconductor 1 is provided on the downstream side of the slit glass 107.
A developing device 109 for developing a toner by adhering a toner to the electrostatic latent image on 03 is installed, and the developing device 109 accommodates a toner 110 mixed with a carrier as a developer. The toner 110 will be described in detail later.

Further, in the developing device 109, a stirring roller 20 for stirring and frictionally charging the developer by rotating the roller 20.
1 and a supply roller 202 for supplying the developer stirred by the stirring roller 201 to a magnet roller 203 described below. Further, in the developing device 109, a magnet roller 203, in which S poles and N poles are alternately arranged along the rotation direction of the roller, is rotated in the direction of arrow l in the drawing in a state of approaching the photoconductor 103. It is possible.

A transfer device 111 and a peeling device 113 are provided on the downstream side of the developing device 109. The transfer device 111 is a device that transfers the toner image formed by the developing device 109 onto a copy sheet (hereinafter referred to as a sheet), and the peeling device 113 uses the transfer device 111 to transfer the toner image to the photoreceptor 10.
3 is a device for peeling the paper adsorbed on the surface from the surface of the photoconductor 103.

Downstream of the peeling device, among the toners 110 attached to the surface of the photoconductor 103, the toners remaining on the photoconductor 103 after being transferred by the transfer device 111.
A cleaning device 115 for removing 110 is provided. Cleaning device 115 and charging charger 10
A static eliminator 117 for lowering the potential of the photoconductor 103 is fixedly installed between 5 and 5.

Further, the main body 101 has an original glass 119 on which an original is placed and an optical system 121 which irradiates the original on the original glass 119 with light and guides the reflected light onto the surface of the photoconductor 103. . The optical system 121 includes a lamp 123 as a light source and mirrors 124, 125, 127, 129, 131, 13 for reflecting light emitted from the light source.
3 and a lens unit 135 for forming an image of reflected light
have.

The lamp 123 and the mirror-124 are constructed so as to be movable under the original glass 119, and in order to always keep the optical path length constant, the mirror-125 and the mirror-127 are half of the lamp 123. It is configured to move at speed. The reflected light from the mirror-133 is configured to pass through the slit glass 107 and be guided to the surface of the photoconductor 103.

A manual feed tray 141 for accommodating sheets is provided in the middle of the right side of the main body 101 in a removable manner, and the main body 1 has a paper tray accommodated in the manual feed tray 141 above the tip of the manual feed tray 141. A pickup roller 143 for pulling out is provided.

On the left side of the main body 101, there is provided a paper discharge tray 171 for discharging copied paper.
Between the manual feed tray 141 and the paper discharge tray 171,
A sheet conveying path, that is, a conveying path 142 is formed, and the conveying path 142 is shown by a dotted line in FIG.

Two roller pairs, a first roller pair and a second roller pair, are attached to the main body 101 upstream of the conveying path 142. First
The pair of rollers is adjacent to the manual feed tray 141, and is connected to the paper feed roller.
It is composed of two rollers, a roller 145 and a separation roller 147. The paper feed roller 145 is a roller that can rotate in the direction of the arrow b in the figure, and is a roller for sending the paper pulled out by the pickup roller 143 to the second roller pair by the rotation of the roller. is there. The separating roller 147 is provided below the paper feeding roller 145 so as to be in contact therewith, and when the number of papers sent from the pickup roller 143 is two or more, the paper feeding roller 145 is rotated. Rotate in the opposite direction,
The excess paper is pulled back to the manual feed tray 141. Separation
When the number of sheets sent from the pickup roller 143 is one, the roller 147 is rotated by the rotation of the sheet feeding roller 145. The second pair of rollers is an upper roller and a lower roller.
It is a registration roller 149 composed of a la. The registration roller 149 abuts against the leading edge of the paper sent from the paper feed roller 145 to align the paper, and then the paper is placed between the photoconductor 103 and the transfer device 111. Send it so that it overlaps with the upper toner image.

The transfer device 1 is provided in the middle of the transport path 142.
11 and a peeling device 113 are arranged, and a belt-shaped belt for transporting paper, that is, a transport belt 15 is provided at the tip thereof.
1 is provided. Further, on the downstream side of the transport path 142, heating and pressurizing the toner 110, the toner 11 is discharged.
A fixing device 153 for fixing 0 on paper is installed. The fixing device 153 includes a heat roller 157 and a pressure roller 1 which are rotatable in directions c and d in the drawing.
Have 59. The heat roller 157 has a built-in heat lamp 155, which is a heating body, and is partially pressure-bonded to the pressure roller 159. The surface of the heat roller 157 is made of a metal member having good thermal conductivity, and the surface of the pressure roller 159 is made of an elastic rubber member so that it can be easily pressure-bonded to the heat roller 157. There is. Further, a discharge roller 161 for discharging the paper loaded with the copying machine to a discharge tray 171 is provided downstream of the transport path 142. The copying process by the copying machine described above is as follows.

First, the surface of the photoconductor 103 is the charging device 10.
5 is uniformly charged. Next, the lamp 123 in the optical system 121 scans under the original glass 119 on which the original is placed, and the original is irradiated with light. When scanning is performed by the lamp 123, the light emitted from the lamp 123 is reflected, and the reflected light is guided to the lens unit 135. The reflected light is inverted by the lens unit 135 and is exposed on the charged photoconductor 103 through the slit glass 107. When the light is exposed, the charge on the surface of the photoconductor 103 is lost and an electrostatic latent image is formed.

In the developing device 109, the stirring roller 201
The toner 110 and the carrier that are agitated and friction-charged are sent to the magnet roller 203 by the supply roller 202. Tona-1 sent to the magnet roller 203
10 and the carrier are S in the magnet roller 203.
A magnetic brush is formed by the magnetic force lines formed between the poles and the N poles. The carrier is always magnetically attracted to the magnet roller 203, and the toner 110 is electrically attracted to the carrier.

Then, when the magnet roller 203 and the photosensitive member 103 rotate and the magnetic brush and the electrostatic latent image on the photosensitive member 103 come close to each other, the toner attracts due to the stronger electrostatic attraction of the electrostatic latent image. 110 separates from the carrier and adheres to the electrostatic latent image. The toner 110 attached to the electrostatic latent image forms a toner image. During development, the developing bias is applied to the magnet roller 203 and the photoconductor 10 by a voltage device (not shown).
The unnecessary toner 110 is prevented from adhering to the photoconductor 103 over the period of 3.

On the other hand, the paper stored in the paper feed cassette 141 is pulled out by the pickup roller 143,
Among the pulled-out sheets, only one sheet is sent to the registration roller 149 by the rotation of the sheet feeding roller 145 and the separation roller 147. The registration roller 149 aligns the leading edge of the sheet and then sends the sheet between the photoconductor 103 and the transfer device 111 to superimpose it on the electrostatic latent image on the photoconductor 103. On the back side of this fed paper,
The toner image is transferred onto the paper by the operation of the transfer device 111. The sheet on which the toner image is formed in this manner is peeled from the surface of the photoconductor 103 by the peeling device 113, is conveyed on the conveyor belt 151, and reaches the fixing device 153.

In the fixing device 153, the heat roller 15 heated by a heat lamp 155 incorporated in advance is used.
7 and the pressure roller 159 rotate in their respective viewpoint directions while partially pressure-bonding. Heat roller 157 and pressure roller
When the roller 159 is rotated, the toner image is fixed onto the paper by passing the paper so that the toner image is on the heater-roller side through the pressure-bonded portions of these two rollers. That is, the heat of the heat roller 157 melts the toner 110, the pressure of the pressure roller 159 enhances the heat conduction efficiency, and the toner is soaked between the fibers of the paper. The paper on which the copy image is formed through the above process is
The sheet is discharged to the sheet discharge tray 171 via the sheet discharge roller 161. Next, various embodiments of the charging member of the present invention applied to the charging device 105 of the copying machine described above will be described with reference to the drawings.

Molten urethane rubber was injected around a 6 mm diameter stainless steel roller cored metal housed in a molding die to produce a conductive elastic roller having a diameter of 12 mm. The molten urethane rubber was composed of 30% by weight of carbon powder (particle diameter 60 μm) as electron conductive particles, and a lithium compound particle mixture (LiO ₂ , LiF, Li) as ion conductive particles.
₂ CO ₃ ) is dispersed and mixed at 10% by weight.

A surface layer made of urethane was coated on the surface of the conductive elastic roller in a film thickness of 10 μm in consideration of the residual toner releasability and the releasability from the photoreceptor. The rubber hardness of the obtained conductive elastic roller is 45 degrees (JIS-
S).

As shown in FIG. 2, the conductive elastic roller 1 obtained as described above is applied to an aluminum base tube 2 having a diameter of 30 mm and having the same diameter as the photosensitive drum as an actual member to be charged. The pressure was applied under a pressure of 1 kg, and the resistance value was measured by the method shown below in an environment of a temperature of 21 ° C. and a humidity of 50%.

First, the voltage applied to the conductive elastic roller 1 from the power source 3 was changed and the current flowing through the conductive elastic roller 1 was measured by the ammeter 4 to obtain the result shown in FIG. . It can be seen from the graph shown in FIG. 3 that the roller inflow current depends on the applied voltage, and therefore the resistance value changes depending on the applied voltage. Since the photoconductor inflow current when actually charging the photoconductor is about several tens of μA, the resistance value when the roller inflow current is 20 μA was used as a standard. Therefore,
A resistance value was obtained by applying a voltage to the roller 1 by constant current control with a roller inflow current of 20 μA. As a result, when the roller inflow current is 20 μA and the applied voltage is 24 V, the resistance value of the roller 1 is 1.2 × 10 ⁶ It was Ω.

Since the surface potential of the roller influences the surface potential of the body to be charged, the resistance value of the roller 1 is not the specific resistivity of the elastic body, but a value obtained by multiplying the layer thickness, that is, per nip area. It is preferable to specify the resistance value of Therefore, when the specific resistivity is ρ, the roller applied voltage is V, the roller inflow current is I, the roller thickness is d, and the nip area is S, the following formula is established. ρ = (V / d) / (I / S) = R · (S / d) ρ × d = R / S (Ω · cm ² )

From these equations, when the length of the roller 1 in the longitudinal direction is 27 cm and the contact nip with the aluminum tube 2 is 1 mm, the resistance value per nip area of the roller 1 is obtained. The spot 1.2 × 10 ⁶ × 27 × 0.1 =
3.2 x 10 ⁶ Ω · cm ² Met. Hereinafter, the resistance value per nip area will be used as the roller resistance value.

Next, the environmental dependence of the resistance value of this roller was investigated. That is, temperature 10 ° C humidity 20% RH, temperature 21 ° C humidity 50% RH, and temperature 30 ° C humidity 85% RH
When the resistance value of the roller was measured under these three environments, the results shown in FIG. 4 were obtained. It can be seen from the graph shown in FIG. 4 that the roller according to this example exhibits a stable resistance value over the entire environment. Further, a DC constant voltage of -1100 V is applied to the charging device 105 of the image forming apparatus described above,
When the screen image was output, a good image was obtained. Comparative Example 1

A conductive elastic roller was manufactured in the same manner as in Example 1 except that only 40% by weight of carbon was dispersed in urethane rubber. The resistance value per nip area between the roller and the member to be charged was calculated to be 2.8.
× 10 ⁶ Ω · cm ² Met. A DC constant voltage of -1100 V was applied to the charging device in the same manner as in Example 1, and a halftone image was output. As a result, uneven density occurred due to uneven charging potential. This is caused by the non-uniformity of the resistance caused by the non-uniformity of the dispersibility resulting from the variation in the particle size of the carbon particles. Comparative example 2

A conductive elastic roller was manufactured in the same manner as in Example 1 except that only 20% by weight of a mixture of lithium compound particles (LiO ₂ , LiF, Li ₂ CO ₃ ) was dispersed in urethane rubber. did. This conductive elastic roller had very good resistance value uniformity, and therefore good charging uniformity. As in Example 1, a half-temperature under normal temperature and pressure.
A good image was obtained when the image was output.

However, as a result of investigating the environmental dependence of the resistance value of this roller, as shown in FIG. 4, the resistance value of this roller greatly changes depending on the environment, especially at 10 ° C. and 20 ° C.
%, The resistance increased significantly at low temperature and low humidity, and the charging potential decreased. In addition, uneven density occurred in the halftone image. Example 2

10% by weight of carbon powder and 5% of a mixture of lithium compound particles (LiO ₂ , LiF, Li ₂ CO ₃ ) were added.
A conductive elastic roller was manufactured in the same manner as in Example 1 except that the dispersion was performed by weight. This conductive elastic roll
When the resistance value per nip area of La was measured by the same resistance measurement method as in Example 1, it was 5.4 × 10 ^7. Ω ・
cm ² Met.

When a high voltage of -1100 V was applied to charge the photoconductor in the same manner as in Example 1, uniform and stable charging regardless of environment was obtained as in Example 1. However, a sufficient charging potential was not obtained. Since the roller resistance is high, discharge is unlikely to occur, and the charging potential of the photoconductor is lowered.

From Examples 1 and 2, the conductive elastic material of the present invention
The optimum resistance value of the roller is 10⁶ Ω · cm² It is
I understand. The resistance value of the conductive elastic roller is 10⁶ Ω ・ c
m² When the voltage exceeds the threshold, the voltage drop in the roller layer is large and the discharge
Is less likely to occur and the required charging potential cannot be obtained. one
However, if the resistance value is too low, a high electric field will be applied to the photoreceptor and
Therefore, defects such as pinholes are likely to occur.

In the above charging member, carbon, tin oxide, indium tin, antimony tin or the like can be used as the electron conductive particles. Carbon is particularly preferable.

As the ion conductive particles, LiO ₂ , L
iF, lithium compounds such as Li ₂ CO ₃ , or a mixture thereof, β-Al ₂ O ₃ , phosphotungstic acid, phosphomolybdophosphoric acid, uranyl hydrogen phosphate, (CH ₃ ) ₄ NOH
・ 5H ₂ O (TMAH5), (CH ₃ ) ₄ NOH ・ 6H
₂ O (TMAH6) and other proton conductors, stabilized zirconia-based electrolytes and other oxygen ion conductors, Ag ions, Cu
Metal conductors such as ions, PbClF, AlNa (S
Ionic crystals such as O ₄ ) ₂ , KMgCl ₃ and NaHSO ₄ can be mentioned.

The compounding ratio of the electron conductive particles and the ion conductive particles dispersed in the charging member of the present invention is usually more in the electron conductive particles, and for example, the weight ratio is preferably 1: 1 to 4: 1. .

As the elastic body used in the charging member of the present invention, there are natural rubber, synthetic rubber, elastomer and the like, specifically, silicone rubber, ethylene propylene rubber, styrene butadiene rubber, acrylic rubber, butadiene rubber and the like. And synthetic rubbers, elastomers such as pyristyrene, polypropylene, polyester and polyamide, and foam rubbers such as urethane foam. Next, various structural examples of the conductive elastic roller will be described.

That is, the conductive elastic roller of the present invention is shown in FIG.
Not only having the single-layer conductive elastic layer 5 as shown in FIG. 6, but also having the protective layer 6 formed on the surface as shown in FIG.
As shown in FIG. 7, it may have a three-layer structure in which a resistance layer 8 is provided on the conductive layer 7 and a surface layer 9 is further provided thereon.

The charging member of the present invention is not limited to the conductive elastic roller 5 as shown in FIG. 8, but may be a blade-shaped member 15 as shown in FIG. It may be a brush-like member 25 as shown in FIG. Note that reference numeral 10 indicates a photoconductor that is a body to be charged.

The bias applied to the charging member is not limited to the DC voltage controlled by the constant voltage, but may be the DC voltage controlled by the constant current, or the bias in which the AC is superimposed on the DC.

[0055]

As described above, according to the present invention,
By containing the electron conductive particles and the ion conductive particles, the problems of both are complemented each other, and a charging member having a uniform resistance and a stable resistance value regardless of environmental changes is obtained. It is possible to obtain a uniform and stable charging potential.

[Brief description of drawings]

FIG. 1 is a diagram showing an image forming apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram showing a method for measuring the resistance value of the charging member of the present invention.

FIG. 3 is a graph showing the relationship between the voltage applied to the charging member and the inflow current.

FIG. 4 is a graph showing a change in resistance value depending on the environment of the charging member.

FIG. 5 is a sectional view showing a conductive elastic roller having a single-layer structure.

FIG. 6 is a cross-sectional view showing a conductive elastic roller having a two-layer structure.

FIG. 7 is a cross-sectional view showing a conductive elastic roller having a three-layer structure.

FIG. 8 is a view showing a roller-shaped charging member.

FIG. 9 is a view showing a blade-shaped charging member.

FIG. 10 is a diagram showing a brush-shaped charging member.

[Explanation of symbols]

 1, 5 ... Roller-shaped charging member 2 ... Aluminum tube 3 ... Power source 4 ... Ammeter 10 ... Photosensitive member 15 ... Blade-shaped charging member 25 ... Brush-shaped charging member 101 ... Copier body 103 ... Photosensitive member 105 Charger 107, slit glass 109, developing device 110, toner 111, transfer device 115, cleaning device 117, static eliminator 119, original glass 121, optical system 201, stirring roller 202, supply roller -La 203 ... Magnet roller

Continuation of the front page (72) Inventor Takeshi Watanabe 70 Yanagicho, Saiwai-ku, Kawasaki-shi, Kanagawa Toshiba Yanagimachi factory

Claims (3)

[Claims] 1. A charging member, which is disposed in contact with or close to a member to be charged and charges the member to be charged,
A charging member comprising ion conductive particles and electron conductive particles. 2. The charging member according to claim 1, wherein the ion conductive particles are made of a lithium compound, and the electron conductive particles are made of carbon. 3. A charging member for charging the image carrier,
A means for exposing the charged image bearing member to form an electrostatic latent image, a developing means for developing the electrostatic latent image formed by the latent image forming means, and a developing means for developing the electrostatic latent image. Transfer means for transferring the developer image onto the image forming medium,
A means for fixing the developer image transferred by the transfer means onto an image forming medium, wherein the charging member contains ion conductive particles and electron conductive particles. apparatus.