JPH07168460A - Color image forming device - Google Patents

Abstract

PURPOSE:To provide a color image forming device capable of preventing the transfer from being defectively executed caused by the fluctuation of a resistance occurring in accordance with the change of the thickness of a transfer material or the change of an environment and obtaining an excellent image. CONSTITUTION:An attraction bias power source 101 is grounded through a pseudo transfer bias power source 103 and the current detection resistance 104. Then, both ends of the resistance 104 are connected to a transfer material judgement circuit 106 through an A/D converter 105. By the judgement circuit 106, the impedance of the transfer material is calculated based on the value of the resistance 104 and the output of a transfer bias power source is changed. Thus, the transfer is appropriately executed and the excellent image is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic or electrostatic recording type image forming apparatus such as a copying machine, a page printer, etc. The present invention relates to a color image forming apparatus that obtains a color image.

[0002]

2. Description of the Related Art Conventionally, color image forming apparatuses are
Electrostatic recording methods using electrophotography are often used. As shown in FIG. 6, these color image forming apparatuses include color developers such as yellow (Y), magenta (M), cyan (C), and black (BK), and the image carrier 1
The developing device 6 for developing the electrostatic latent image formed thereon, and the supplied transfer material 9 are held by a transfer material holding means (not shown) such as electrostatic adsorption or a gripper, and the transfer material 9 is held by an image carrier. 1
A transfer body 2 for transferring the above image, an electrostatic latent image written by an optical signal emitted from an exposure device 8 having a light source such as a laser, and a visible image developed by the developing device 6 are both carried. Image carrier 1, a primary charger 7 that uniformly charges the surface of the image carrier 1, a cleaner 3 that cleans the developer remaining on the image carrier 1 after the image is transferred to the transfer material 9, and a transfer material 9. The color visible image transferred onto the transfer material 9 is fixed on the transfer material 9.

As shown in FIG. 7, the transfer body 2 in the above apparatus has a hollow drum casing 22 side surface notched only in the transfer region, and in the notched portion, polyethylene terephthalate (PET), polyvinylidene fluoride (PVdF), and fluorine are used. Sheet 21 typified by poly (ethylene propylene) copolymer (FEP), polycarbonate, polyurethane, etc.
The structure is stretched. As shown in FIG. 6, a suction roller 10 as a means for electrostatically attracting the transfer material 9 to the flexible sheet 21 is provided inside and outside the transfer body 2 and faces the suction roller 10. And flexible sheet 21
Adsorption charger 11 for charging the toner, and transfer charger 1 as a means for transferring the image formed on the image carrier 1.
2, a separation charger 13 for separating the transfer material 9 electrostatically attracted to the flexible sheet 21, a separation claw 15 for assisting the separation and guiding the separated transfer material 9 to the fixing device 5, and A sheet discharging charger 14 for initializing the flexible sheet 21 and a transfer body cleaner 4 are arranged.

The image forming process of the color image forming apparatus having the above-described apparatus will be described. First, the first color formed on the image carrier 1 by exposure based on the image signal of the first color from the exposure device 8. The electrostatic latent image of is visualized by the developing device 6 containing a yellow (Y) developer, for example. In parallel with this step, the transfer body 2 holds the front end of the supplied transfer material 9 by a gripper or the like as a transfer material holding means, and then rotates to transfer the transfer material 9 to the transfer body 2.
Wrap it around the surface. At this time, the transfer material 9 is sandwiched between the suction roller 10 and the flexible sheet 21 forming the surface of the transfer body 2, and at the same time, the flexible sheet 2 is held by the suction charger 11.
1 is held on the front surface of the transfer body 2 by the electric charge applied to the back surface.

Subsequently, the transfer material 9 is conveyed by the rotation of the transfer body 2 to an image transfer portion located at a position facing the image carrier 1, and the image formed on the image carrier 1 is transferred to the image carrier 1. The image is transferred by the transfer charger 12 which is arranged so as to oppose to. After that, the residual developer remaining on the image carrier 1 is removed by the cleaner 3, and the image carrier 1 is exposed again.
Thus, an electrostatic latent image based on the image signal of the second color is formed on the image carrier 1. This electrostatic latent image is developed by the developing device 6 that contains, for example, a magenta (M) developer corresponding to the image signal of the second color, and becomes a visible image. The visible image of the second color is transferred by the transfer charger 12 again to the transfer material 9 on the transfer body 2 to which the visible image of the first color has been transferred. With the above process as the third color, cyan (C), 4
A visible image of the third color and the fourth color is formed on the image carrier 1 by using a developer such as black (BK) as the color, and is transferred to the transfer material on the transfer body 2 in the same manner as the visible image of the second color. Overprint.

The transfer material 9 to which the color visible images of each color are transferred as described above is conveyed by the rotation of the transfer body 2 to the separation charger 13 arranged inside and outside the transfer body 2 so as to face the separation charger 13. The electrostatic attraction force between the transfer material 9 and the flexible sheet 21 is removed by the charger 13, and the transfer material 9 and the flexible sheet 21 are separated via the separation claws 15. The separated transfer material 9 is guided to the fixing device 5,
The visible image transferred by the fixing device 5 is fixed. The transfer body 2 after the transfer material is separated is neutralized by the sheet charge-eliminating charger 14 to be electrically initialized, and the developer attached to the surface of the transfer body 2 is removed by the transfer body cleaner 4.

As described above, the transfer member 2 having a cutout structure has been described as a typical example of the transfer member used in the case of forming a color image by the multiple transfer method. However, as shown in FIG. Elastic drum casing 22 'is coated with an elastic member 23 such as urethane foam or silicone rubber foam,
Further, by the method of applying a bias to the transfer body 2'having a structure in which the surface thereof is covered with the flexible sheet 21 'as described above, the multiple transfer similar to that of the cutout drum can be performed.

In this type of transfer body 2 ', since the inside can be simplified as compared with the transfer body 2 having the cutout structure described above, the cost can be reduced and the flexible sheet 21' is supported from the inside. There is an advantage that the deformation and damage of the sheet, which is a problem of the transfer body 2 having the cutout structure, can be reduced.
Therefore, the conductive drum 2 which does not currently have the above-mentioned cutout portion is used.
A color image forming apparatus using 2 '(hereinafter referred to as a bias drum) has been receiving attention. The image forming method of the color image forming apparatus using the bias drum is very similar to the same apparatus using the cutout drum described above.

Image formation of a color image forming apparatus using the above bias drum will be described below with reference to FIG. 9, but among the image forming means shown in FIG.
The same symbols and numerals are given to those having the same arrangement and function as those of the color image forming apparatus, and detailed description thereof will be omitted.

First, the transfer material 9 supplied from the conveying path is
Adsorption roller 11 as an adsorption charger that comes in contact with and separates from the transfer body 2.
It is sandwiched between the transfer body 2 and the suction roller 11. At the same time, a suction and transfer bias is applied to the drum housing 22 'and the suction roller 11, and the transfer material 9 is electrostatically held on the transfer body 2 by the electric charges induced by the bias. Then, the transfer material 9 held by the transfer body 2 is conveyed to the image transfer portion by the rotation of the transfer body 2, and the first color visible image formed on the image carrier 1 is transferred.

Next, when transferring the visible image of the second color, the above-mentioned transfer bias value is varied so that the potential dropped by the transfer material 9 on the transfer body 2 transferring the visible image of the first color. to correct. Such correction is similarly performed at the time of transferring the third color and the fourth color, and the visible image formed on the image carrier 1 is superposed on the transfer material 9 on the transfer body 2. The transfer material 9 that has completed the transfer process is neutralized by the separation charger 13 and transferred to the transfer body 2.
After the electrostatic attraction force between and is removed, they are separated via the separation claws 15.

The transfer material 9 onto which the visible image has been transferred is conveyed to the fixing device 5 and fixed by the fixing device 5 to form a permanent image.

The transfer process in the color image forming apparatus using the bias drum has been described above. The developing process in the color image forming apparatus is the same as the developing process in the color image forming apparatus using the cutout drum described above. Is.

[0014]

The transfer bias control in the color image forming apparatus described above uses constant current control in a color image forming apparatus using a cutout drum, whereas in the color image forming apparatus using a bias drum. In the apparatus, the transfer bias is controlled by constant voltage control for the following reasons. FIG. 10 shows an example of a bias power supply configuration used for a transfer body of a bias drum. Further, FIG. 11 shows a sequence diagram of the color image forming apparatus. As can be understood from FIGS. 10 and 11, a transfer body 2 using a bias drum is used.
In this case, since the attraction roller 11 and the static elimination roller 14 as the static elimination charger are in contact with each other during one image formation, there are a plurality of counter electrodes seen from the transfer body 2 and they change during the image formation. . Therefore, even if the current is detected by A or B in the figure and the constant current is controlled, the current also flows through the attraction roller 11 and the charge eliminating roller 14, so that the transfer current value between the transfer body 2 and the image carrier 1 is kept constant. You can't control it. On the contrary, the image carrier 1 to GN, which is the counter electrode in FIG.
When the value of the current flowing in D is fed back, the sum of the charging current from the primary charger 7 and the developing current from the developing device 6 and the transfer current Itr to be actually controlled is detected as the current detected in C in the figure. Therefore, it is difficult to control the transfer current value.

As described briefly above, in the transfer body 2 using the bias drum, the transfer current Itr flowing during the image transfer to the image carrier 1 and the transfer body 2 cannot be directly controlled, so that the image carrier is formed. The transfer current value is controlled to be constant by applying a constant voltage according to the impedance between the transfer member 1 and the transfer member 2.

However, as can be understood from the equivalent circuit shown in FIG. 12, the impedance between the image carrier 1 and the transfer member 2 is the electrostatic capacitance Cp and the resistance value Rp of the transfer material 9.
Changes significantly with the change in the transfer current Itr
The transfer voltage Vtr when the current flows also largely depends on the impedance of the transfer material 9. Therefore, for example, even if the transfer voltage Vtr is set so that an appropriate transfer current Itr flows in the transfer material 9 having a thickness of about 60 μm, the transfer current Itr is insufficient for the transfer material 9 having a thickness of 100 μm, resulting in poor transfer. Occurs. On the other hand, in the opposite case, the transfer voltage Vtr is too strong and abnormal discharge occurs at the transfer portion, which disturbs the transferred image. Furthermore, even in the case of the same transfer material 9, the resistance value Rp changes depending on the environment, so that a transfer failure occurs similarly to the change of the electrostatic capacitance Cp. In particular, the resistance change due to the moisture absorption of the transfer material 9 has a time lag between the temperature change and the humidity change of the atmosphere, which is difficult to predict from the temperature change of the atmosphere.

Therefore, an object of the present invention is to make it possible to apply a transfer bias corresponding to the fluctuation of the impedance of the transfer material to the transfer drum, and prevent the transfer failure due to the resistance fluctuation due to the change of the thickness of the transfer material or the environment, It is an object of the present invention to provide a color image forming apparatus capable of obtaining a good image.

[0018]

The above object can be achieved by a color image forming apparatus according to the present invention. In summary, the present invention comprises an image carrier having a photoconductive photosensitive layer on a conductive substrate, and a dielectric layer on the surface, and a visible image on the image carrier is formed on the back surface of the dielectric layer. A transfer body that transfers a plurality of times to a transfer material held by a transfer bias applied from a certain back electrode, an attraction charger that electrostatically attracts the transfer material to the transfer body by an attraction bias, and an amount of current flowing into the attraction charger. In a color image forming apparatus having a current detecting means for detecting a transfer bias, an output of a transfer bias power source for applying a transfer bias to a transfer body in response to a change in an adsorption current flowing into the adsorption charger in the process of adsorbing a transfer material. Is a variable color image forming apparatus.

According to another aspect of the present invention, an image carrier having a photosensitive layer on a conductive substrate and a dielectric layer on the surface are provided.
A transfer body that transfers a visible image on the image carrier to a transfer material held multiple times by a transfer bias applied from a back electrode on the back surface of the dielectric layer, and an electrostatic bias of the transfer material to the transfer material by an attraction bias. In a color image forming apparatus having an adsorption charging device for adsorbing and a voltage detecting means for detecting a voltage output from the adsorption charging device, a change in the voltage output from the adsorption charging device in the process of adsorbing a transfer material is dealt with. Then, the output of the transfer bias power source for applying the transfer bias to the transfer body is made variable, and the color image forming apparatus is provided.

An adsorption bias power source section having an adsorption bias power source for outputting an adsorption bias to the adsorption charger and a pseudo transfer bias power source for outputting the same bias in conjunction with the transfer bias power source is provided, and the current detection means is provided. Is preferably provided between the reference potential of the pseudo transfer bias power source and the ground of the casing of the apparatus main body.

A reference potential of an attraction bias power source for outputting an attraction bias to the attraction charger is connected to an output end of the transfer bias power source, and the current detecting means is provided between the attraction charger and the attraction bias power source. It is preferable that the reference potential is interposed between the reference potential and the connection end connected to the output end of the transfer bias power supply.

The reference potential of the attraction bias power supply for outputting the attraction bias to the attraction charger is connected to the output end of the transfer bias power supply, and a pseudo load is provided between the output end of the attraction bias power supply and the chassis ground. It is preferable to provide the current detection means.

Preferably, the adsorption charger is a brush charger using a conductive brush.

[0024] Preferably, the adsorption charger is a blade charger using a conductive blade.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a color image forming apparatus according to the present invention will be described below in more detail with reference to the drawings. In the embodiments described below, the present invention will be described as being embodied in the color image forming apparatus shown in FIG.

Embodiment 1 A first embodiment of the color image forming apparatus according to the present invention will be described with reference to FIGS.

In FIG. 1 schematically showing the bias power source of the color image forming apparatus, the attraction bias power source 101 constituted by a constant voltage power source outputs an output equivalent to that of the transfer bias power source 102 in synchronization with the transfer output timing. It is configured on the pseudo transfer bias power source 103. The pseudo transfer bias power source 103 is grounded via a current detection resistor 104 as a current detection means, and the current detection resistor 1
Both ends of 04 are connected to the transfer material judgment circuit 106 via the A / D converter 105. The transfer material judgment circuit 106
The impedance of the transfer material is calculated based on the value of the current detection resistor 104, and the output of the transfer bias power supply 102 is changed so that proper transfer can be performed at that impedance.

When the attracting current Iab at the time of attracting the transfer materials 9 having different physical property values and the attracting current Iab at which the transfer current Itr of about 5 μA capable of optimal transfer to the transfer material 9 attracted to the transfer body 2 flows. The relationship of the transfer bias voltage Vtr is shown in the graph of FIG. The graph shows process speed 1
This is the relationship obtained when PVDF having a thickness of 06 mm / sec and a thickness of 75 μm was used as the flexible sheet.

Based on the above three relationships shown in the graph of FIG. 2, if an appropriate transfer bias voltage Vtr is applied to the transfer body 2 by the transfer material judgment circuit 106 from the value of the attracting current flowing through the current detecting resistor 104 at the time of attracting. A proper transfer current Itr flows from the transfer body 2 to the image carrier 2. Here, the three relationships shown in the graph of FIG. 2 are the transfer bias of the first color, but the transfer biases of the second and subsequent colors have the same relationship with the impedance of the transfer material 9 as the transfer bias of the first color. Therefore, it is decided based on the relationship.

An example of calculating the transfer bias voltage Vtr from the attracting current Iab has been described above. However, the optimum transfer current value has a certain allowable range, and the graph of FIG. 2 has a certain degree as shown in the graph of FIG. Vtr-Z with the area of
A curve can be shown. Therefore, even if the transfer voltage Vtr is not finely changed with respect to the change in the impedance of the transfer material 9, for example, the impedance of the transfer material 9 is set to high, medium,
The transfer bias voltage Vtr is classified as V
It may be tr1, Vtr2, or Vtr3.

As the timing for detecting the attraction current Iab, the current is detected within the time from the attraction start time T1 to the transfer start time T2 in the sequence diagram of the color image forming apparatus shown in FIG. Calculate the value,
You can control it. In addition, this control is preferably performed for each printing, because when the different transfer materials 9 are used, the same transfer material 9 may have different moisture absorption states.

As described above, in the present embodiment, the impedance of the transfer material 9 is obtained by measuring the current value of the adsorption bias power source 101 whose constant voltage is controlled. However, the adsorption bias power source 101 is composed of a constant current circuit, and its output voltage is Needless to say, the impedance of the transfer material 9 can be measured even if the voltage is detected, and the conventionally used high voltage measuring means may be used as the voltage detecting means.

Although the roller charger is used as the attraction charger 11 in this embodiment, the attraction charger 11 can be brought into contact with or separated from the transfer body 12, and comes into contact with the transfer material 9 to regulate the conveyance. Therefore, a contact charging method such as a brush charger using a conductive brush or a blade charger using a conductive blade may be used.

Second Embodiment Next, a second embodiment of the color image forming apparatus according to the present invention will be described with reference to FIG.

The attraction bias power source 101 composed of the constant voltage power source shown in FIG. 4 obtains the reference potential from the output end of the transfer bias power source 102, and the attraction bias power source 10
A current detection resistor 104 that measures the attraction current Iab is connected between the transfer bias power supply 102 and the transfer bias power supply 102. Unlike the first embodiment, both ends of the current detection resistor 104 are connected to the transfer material detection resistor 106 via the photo coupler 107 and the A / D converter 105, and the transfer material determination circuit 10 is further connected.
Reference numeral 6 is connected to the transfer bias power source 102.

In the case of this embodiment, unlike the first embodiment,
Since the pseudo transfer bias power supply 103 does not have to be used, the bias circuit is simplified, and the number of costly components such as a transformer can be reduced, which has the advantage of cost reduction. Further, it is needless to say that the same action and effect as those of the first embodiment can be obtained.

Third Embodiment Next, a third embodiment of the color image forming apparatus according to the present invention will be described with reference to FIG.

The attraction bias power source 101 composed of the constant voltage power source shown in FIG. 5 obtains the reference potential from the output end of the transfer bias power source 102 as in the second embodiment. However, unlike the second embodiment, the current detection resistor 104 is connected to the output end of the attraction bias power supply 101 via a pull-up resistor 108 that is approximately equal to the smallest impedance of the transfer material 9 that can be used in this color image forming apparatus. Is arranged between the output end of the adsorption bias power supply 101 and GND.
A switching contact 109 is provided between the pull-up resistor 108 and the current detection resistor 104, and the current detection resistor 1
A pseudo resistor 110 for GND is provided on the opposite side of the terminal to which 04 is connected.

The pull-up resistor 108 used in this embodiment
For this, a resistor of several thousand K to several hundred MΩ was used in consideration of the impedance of the entire bias circuit. In the case of this embodiment,
At the time of detecting the transfer current, the switching contact 109 described above is connected to the current detection resistor 104 side, and the impedance of the transfer material is the current detected by the current detection resistor 104 in the form of comparison with the pull-up resistor 108. The value is indirectly obtained by utilizing the correlation between the value and the impedance of the transfer material 9.

In the present embodiment, the switching contact 109 is switched to use the current detection resistor 104 only when the adsorption current is measured, and the switching contact 109 is connected to the pseudo resistor 110 side by the time of image transfer when the transfer bias power source 102 operates. Has been done. The pseudo resistor 110 used in this embodiment is so large that the impedance between the transfer body 2 and the image carrier 1 can be ignored as compared with the impedance between the transfer body and the image carrier at the time of image formation including the transfer material. If there is no problem. Further, since the attraction bias power supply 101 outputs the bias under constant voltage control, the potential of the bias supplied to the attraction roller 11 does not change even by the switching contact 109. Therefore, switching of the switching contact 109 during the suction process does not affect the suction process.

[0041]

As is apparent from the above description, in the color image forming apparatus according to the present invention, the transfer bias is applied to the transfer member in response to the change in the adsorption current flowing into the adsorption charger in the process of adsorbing the transfer material. The output of the transfer bias power supply that applies the voltage is variable, so the transfer bias can be applied to the transfer body according to the change in the impedance of the transfer material, and the transfer due to the resistance change due to the change of the transfer material thickness or environment. Defects can be prevented, and thus a good image can be obtained.

According to another aspect, the output of the transfer bias power source for applying the transfer bias to the transfer member is made variable in response to the change in the voltage output from the adsorption charger during the process of adsorbing the transfer material. With such a configuration, the same operation and effect as above can be obtained.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a bias power supply in a first embodiment of a color image forming apparatus according to the present invention.

FIG. 2 is a graph showing a relationship between an attraction current, a transfer current, and a transfer bias voltage when attracting transfer materials having different physical property values.

FIG. 3 is a graph showing a Vtr-Z curve when an allowable range is given to the optimum transfer current value in the graph of FIG. 2.

FIG. 4 is an explanatory diagram showing a bias power supply of a second embodiment.

FIG. 5 is an explanatory diagram showing a bias power supply of a third embodiment.

FIG. 6 is a configuration diagram of a conventional color image forming apparatus including a transfer body having a cutout structure.

FIG. 7 is a schematic perspective view showing a transfer body having a notch structure.

FIG. 8 is a schematic perspective view showing a transfer body of a bias drum.

FIG. 9 is a configuration diagram of a conventional color image forming apparatus including a transfer body of a bias drum.

FIG. 10 is an explanatory diagram showing a bias power supply of the color image forming apparatus of FIG.

11 is a timing chart showing an image forming sequence of the color image forming apparatus of FIG.

FIG. 12 is an equivalent circuit between the image carrier, the transfer material, and the flexible sheet.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Image carrier 2 Transfer drum (transfer body) 11 Adsorption charging device 14 Electrification charging device 101 Adsorption bias power supply 102 Transfer bias power supply 103 Pseudo transfer bias power supply 104 Current detection resistance (current detection means)

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Moto Kato 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Nobuaki Kamiya, 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Incorporated (72) Inventor Takehiko Suzuki 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (7)

[Claims] 1. A back electrode which comprises an image carrier having a photoconductive photosensitive layer on a conductive substrate, and a dielectric layer on the surface thereof, and a visible image on the image carrier is provided on the back surface of the dielectric layer. A transfer body that transfers a plurality of times to a transfer material held by a transfer bias applied from a device, an adsorption charger that electrostatically adsorbs the transfer material to the transfer body by an adsorption bias, and the amount of current flowing into the adsorption charger is detected. In a color image forming apparatus having a current detecting means, the output of a transfer bias power source for applying a transfer bias to a transfer member is variable in response to a change in an adsorption current flowing into the adsorption charger in the process of adsorbing a transfer material. A color image forming apparatus comprising: 2. An image carrier having a photosensitive layer on a conductive substrate, and a dielectric layer on the surface, and a visible image on the image carrier is applied from a back electrode on the back surface of the dielectric layer. A transfer body that transfers a plurality of times to a transfer material held by a transfer bias, an adsorption charging device that electrostatically adsorbs the transfer material to the transfer material by an adsorption bias, and a voltage detection unit that detects the voltage output by the adsorption charging device. In the color image forming apparatus having the above, it is possible to change the output of the transfer bias power source that applies the transfer bias to the transfer body in response to the change in the voltage output from the adsorption charger in the process of adsorbing the transfer material. Characteristic color image forming apparatus. 3. An adsorption bias power supply unit having an adsorption bias power supply for outputting an adsorption bias to the adsorption charger and a pseudo transfer bias power supply for outputting the same bias in association with the transfer bias power supply, and the current 2. The color image forming apparatus according to claim 1, wherein the detecting means is provided between the reference potential of the pseudo transfer bias power source and the ground of the casing of the apparatus main body. 4. A reference potential of an attraction bias power source for outputting an attraction bias to the attraction charger, is connected to an output end of the transfer bias power source, and the current detection unit is configured to detect the attraction charger and the attraction bias. 2. The color image forming apparatus according to claim 1, wherein the reference potential of the power supply is interposed between the reference potential of the power supply and the connection end connected to the output end of the transfer bias power supply. 5. A reference potential of an attraction bias power supply for outputting an attraction bias to the attraction charger is connected to an output end of the transfer bias power supply, and the output end of the attraction bias power supply is connected to the housing ground of the apparatus main body. 2. The color image forming apparatus according to claim 1, wherein the current detecting means is provided in the sheet through a pseudo load. 6. The charging device according to claim 1, wherein the adsorption charging device is a brush charging device using a conductive brush.
One of the color image forming devices. 7. The color image forming apparatus according to claim 1, wherein the adsorption charger is a blade charger using a conductive blade.