JPH07199602A - Image forming device - Google Patents

Abstract

(57) [Summary] [Purpose] The dirt on the surfaces of the charging roller and the transfer roller is removed with a relatively simple structure. Also, a voltage is applied to these rollers in a highly reliable manner. [Structure] The charging roller 2 and the transfer roller 3 are provided with a pressing means 2.
0, 30 presses through the cleaning members 22, 32 to bring them into pressure contact with the photosensitive member 1, and the conductive portions 22a, 32a of the cleaning members 22, 32 have a voltage from the power sources 4, 5 respectively. Is applied. As a result, electrical conduction is made more reliable as compared with a configuration in which a voltage is applied to the cored bar portion serving as the shaft portion of the charging roller 2 and the transfer roller 3. Also, the pressurizing means 2
When the pressures of 0 and 30 are applied, the surfaces of the charging roller 2 and the transfer roller 3 are in contact with the cleaning members 22,
Since it is cleaned by 32, it is possible to prevent uneven charging and uneven transfer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic image forming apparatus such as an electrostatic copying machine, an optical printer, a facsimile, etc., which is equipped with a charging roller and a transfer roller that rotate in contact with the surface of a rotating photoconductor. Regarding the device.

[0002]

2. Description of the Related Art For example, an electrophotographic image forming apparatus such as an electrostatic copying machine, an optical printer, a facsimile or the like is equipped with a device for charging a photoconductor as a member to be charged. The corona charging device has been widely used because it can uniformly charge the surface of the body to be charged. Also in the transfer step, the toner image formed on the surface of the photoconductor has been transferred to the transfer paper by using corona discharge.

However, in the case of charging and transfer using this corona discharge, ozone and nitrogen oxides are generated along with the corona discharge, which are harmful to the human body and adversely affect the environment. In addition, there is a drawback in that image deterioration is apt to be caused by the addition of ozone and nitrogen oxides to the respective parts of the photoconductor, the charger, the optical system and the like.

Therefore, recently, as a charging device and a transfer device having almost no such drawbacks as described above, a roller-shaped or belt-shaped charging member or a transfer member to which a voltage is applied is brought into direct contact with the photosensitive member to charge the photosensitive member. And a direct contact method of transferring the image on the photoreceptor to a transfer paper has been proposed. In such a direct contact type, when the surface of the charging member or the transfer member is soiled with toner or the like, uneven charging or uneven transfer may occur.

Contamination on the surface of the charging member is caused by cleaning leakage due to cleaning of the surface of the photosensitive member performed after the image is transferred onto the transfer paper when the charging member is a charging roller, so that the toner is removed from the photosensitive member. When a trace amount remains on the surface, it is transferred to the rotating charging roller while contacting the surface of the photoconductor.

When the transfer member is a transfer roller, for example, when the transfer member is a transfer roller, the toner of the image portion formed on the surface of the photosensitive member is transferred to the transfer roller at a time when the transfer member is a transfer roller. For example, the toner adhered to the transfer roller or the toner adhered to the so-called background portion of the non-image area of the photoreceptor is transferred and accumulated on the transfer roller.

Further, in the case where the charging roller and the transfer roller are configured so as to be in contact with the photosensitive member under a constant pressure even when the apparatus is not used, the contact portion with the photosensitive member. May be locally deformed or the photoreceptor may be deteriorated. In such a case, charging or transfer may not be performed in a portion corresponding to the contact portion, and thus a white blank portion corresponding to that portion may be formed on the transfer paper.

Therefore, in order to solve these problems,
The charging roller can be brought into and out of contact with the photoconductor by a mechanical method (see, for example, Japanese Patent Laid-Open No. 1-207768), and the transfer roller can be brought into and out of contact with the photoconductor by a mechanical method (see, for example, Japanese Laid-Open Patent Publication No. No. 35276/1993) is proposed.

There is also proposed a cleaning member provided to clean the surface of the charging roller to remove dirt due to toner or the like adhering to the surface (for example, Japanese Patent Laid-Open No. 2-301777). reference).

Further, when a large amount of toner adheres to the transfer roller due to the occurrence of a jam or the like, a voltage having a reverse polarity to that at the time of transfer is applied to electrically return the toner adhered to the transfer roller to the photoconductor. The method described above is also proposed (see, for example, Japanese Patent Application Laid-Open No. 1-292385).

Further, the conventional application of the voltage to the charging roller and the transfer roller has been carried out to the cored bar portion which is the shaft portion of the conventional one (for example, Japanese Patent Laid-Open Nos. 1-204081 and 3-203). 35276).

[0012]

However, in the case of an image forming apparatus in which the charging roller and the transfer roller can be brought into contact with and separated from the photoconductor by a mechanical method, the respective rollers are brought into contact with and separated from each other. For this reason, a contact / separation mechanism using, for example, a cam, a lever, a solenoid, etc. is required, and thus the structure tends to be complicated.

Further, on the surface of the charging roller and the transfer roller,
When each cleaning member is contacted only when it is cleaned so as to remove the toner and the like adhering to the surface of each roller, a mechanism for contacting and separating those cleaning members is required. There is a problem that the number of parts increases, the configuration becomes complicated, and the cost also increases.

Further, the toner attached to the transfer roller is
In the case of the method of electrically returning to the photoconductor by applying a voltage of the opposite polarity to that at the time of transfer, since the movement of the charge is used, the low-charged toner (uncharged toner) existing in the toner adhering to the background portion is used. It was difficult to return even the toner (including toner) and the oppositely charged toner to the photoconductor.

Further, there is a problem that this toner electrical cleaning method cannot be applied to a charging roller. Further, in the conventional image forming apparatus, it is usual to apply the voltage to the charging roller and the transfer roller through each shaft portion (core metal) of those rollers, so that there is concern about electrical conduction. It was

The present invention has been made in view of the above problems, and it is possible to remove dirt due to toner or the like adhering to the surfaces of the charging roller and the transfer roller with a relatively simple structure. In order to obtain a stable and high-quality image for a long period of time. Another object is to enable application of voltage to the charging roller and the transfer roller by highly reliable electrical conduction.

[0017]

In order to achieve the above object, the present invention provides an image forming apparatus as described above,
Each cleaning member in contact with the charging roller and the transfer roller is provided with a conductive portion, and a voltage is applied from the power source to the charging roller and the transfer roller through the conductive portion. A pressurizing unit is provided which presses each of the cleaning members to bring them into pressure contact with the photosensitive member.

In the above image forming apparatus, it is preferable that the charging roller and the transfer roller are arranged at positions symmetrical with respect to the rotation center of the photosensitive member.

[0019]

According to the image forming apparatus having the above-described structure, the charging roller and the transfer roller are pressed by the pressing means through the respective cleaning members so that they are brought into pressure contact with the photoconductors, respectively, and the conductivity of the respective cleaning members is improved. Since a voltage is applied from the power supply to the conductive portion of the charging roller, the electrical voltage applied to the charging roller and the transfer roller is higher than that in the configuration in which the voltage is applied to the core metal portion that is the shaft of the charging roller and the transfer roller. The conduction can be made more reliable.

Further, when the pressing means presses the charging roller and the transfer roller against the photosensitive member through the cleaning members, the surfaces of the charging roller and the transfer roller are cleaned by the cleaning members which are pressed against them. Therefore, charging unevenness and transfer unevenness can be prevented.

Further, by disposing the charging roller and the transfer roller in point symmetry with respect to the center of rotation of the photosensitive member, the photosensitive member is pressed when the charging roller and the transfer roller are pressed against the photosensitive member by the pressing means. Since a symmetrical position with respect to the center is pressed by the charging roller and the transfer roller in a well-balanced manner, a force that moves in a specific direction is applied like when pressing at a position other than the symmetrical position. Since there is no such thing, stable rotation is always possible.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be specifically described below with reference to the drawings. FIG. 1 is a schematic view showing a state around a photoconductor when an electrostatic copying machine which is an image forming apparatus according to an embodiment of the present invention is not copying, and FIG. It is a schematic diagram showing the state near the body.

First, the copy operation by this electrostatic copying machine will be described. In this electrostatic copying machine, a photosensitive member 1 rotating in the direction of arrow A in FIG. 1, a charging roller 2 and a transfer roller 3 rotating in contact with a surface 1a thereof, and a voltage applied to each of the rollers 2 and 3, respectively. The image forming apparatus of the contact charging type is provided with power sources 4 and 5 for applying a voltage and cleaning members 22 and 32 for cleaning the surfaces of the charging roller 2 and the transfer roller 3.

Then, the photosensitive member 1 rotates in the direction of arrow A at a predetermined peripheral speed, and as shown in FIG. To rotate driven.

Around the photoconductor 1, a developing device 6 and a cleaning unit 8 are provided in addition to the charging roller 2 and the transfer roller 3 as shown in FIG.
Light from the exposure device 9 is incident on the surface 1a of the photoconductor 1,
The surface 1a uniformly charged by the charging roller 2 is exposed to form an electrostatic latent image on the surface 1a, which is developed by the toner supplied by the developing sleeve 6a of the developing device 6 to form a toner image (visible image). ).

On the other hand, the transfer paper P in a paper feed cassette (not shown) is sent out one by one by a paper feed roller which rotates at a predetermined timing, and the timing thereof is adjusted to form a toner image on the photoconductor 1. It is conveyed toward the transfer portion provided with the transfer roller 3 at the exact timing of coincidence.

A toner image is transferred onto the upper surface of the transfer paper P in FIG. 1 (the transfer paper P is not conveyed originally because it is in a non-copying state, but it is shown for convenience of description), which is It is separated from the photoconductor 1 and conveyed to a fixing device (not shown), where the toner is fixed and then discharged to a discharge tray or the like outside the device.

After the transfer is completed, the residual toner remaining on the photoconductor 1 and foreign matter such as paper dust are removed by the cleaning blade 8a provided in the cleaning unit 8, and the residual toner left on the photoconductor 1 is removed. The potential is removed by a discharge lamp (not shown) to prepare for the next charging by the charging roller 2.

The charging roller 2 is formed by integrally mounting a conductive rubber roller portion made of, for example, EPDM (a terpolymer of ethylene propylene diene) on the outside of a cored bar made of iron or the like, and both ends of the cored bar. Is rotatably attached to one end of the roller support arm 21 of the pressing means 20 via a bearing (not shown).

Similarly, the transfer roller 3 has an elastic layer formed on the outside of a cored bar (support shaft), and a thin conductive layer and a resistance layer formed on the outside of the cored bar. The roller support arm 31 of the means 30 is rotatably attached to one end of the roller support arm 31 via a bearing (not shown).

The pressurizing means 20 and 30 are similar,
The pressing means 20 presses the charging roller 2 through the cleaning member 22 to bring it into pressure contact with the photoconductor 1, and the pressing means 30 presses the transfer roller 3 through the cleaning member 32 and comes into press contact with the photoreceptor 1. Let

The pressurizing means 20 swings the pressurizing arm 23 whose center is supported by the shaft 11 so that the pressurizing arm 23 is swingable, and one end of the pressurizing arm 23 is engaged with the pressurizing arm 23. It includes a solenoid 24 and a spring 25 for returning the pressure arm 23 to the position shown in FIG. 1 when the solenoid 24 is off.

The shaft 11 supporting the pressure arm 23 is
The other end of the roller support arm 21 that rotatably supports the charging roller 2 at one end is also swingably supported. Also,
A cleaning member 22 for cleaning the surface of the charging roller 2 is attached to a position of the pressure arm 23 corresponding to the charging roller 2.

Similarly, the pressurizing means 30 has a shaft 11 at the substantially center thereof.
The pressure arm 33 that is swingably supported by the pressure arm 33, and the pressure arm 33 that engages with one end of the pressure arm 33.
And a spring 35 that returns the pressure arm 33 to the position shown in FIG. 1 when the solenoid 34 is off.

The shaft 11 that supports the pressure arm 33 is
The other end of the roller support arm 31 that rotatably supports the transfer roller 3 at one end is also swingably supported. Also,
A cleaning member 32 for cleaning the surface of the transfer roller 3 is attached to the position of the pressure arm 33 corresponding to the transfer roller 3.

Each of the cleaning members 22 and 32 includes
The conductive portions 22a and 32a having conductivity and the cleaning portions 22b and 32b having high cleaning property are provided,
The cleaning portions 22b and 32b are provided on the upstream side of the charging roller 2 and the transfer roller 3 in the respective rotation directions, and the conductive portion 22 is provided on the downstream side thereof.
a and 32a are arranged respectively.

Then, a voltage is applied from the power sources 4, 5 to the charging roller 2 and the transfer roller 3 via the respective conductive portions 22a, 32a. In this electrostatic copying machine, when the copying operation is stopped, the solenoids 24 and 34 of the pressurizing means 20 and 30 are both in the OFF state (non-suction state) as shown in FIG. The photoconductor 1 also stops rotating. Further, no voltage is applied from the power sources 4 and 5.

In this state, the pressurizing means 20 and 30 are in a non-pressurized state, and the pressurizing arms 23 and 33 are connected to the spring 2 respectively.
It is in the position shown in FIG. 1 by the urging forces of 5, 35. Therefore, the charging roller 2 and the transfer roller 3 both swing by their own weights around the shaft 11 as a fulcrum, the charging roller 2 is lightly contacted with the surface 1a of the photoconductor 1 as shown in the drawing, and the transfer roller 3 is moved by the photoconductor 1 is separated from the surface 1a.

In this state, when the copy start key is pressed to start the copy operation, the photosensitive member 1 rotates in the direction of arrow A, and the discharging means (not shown) is turned on in synchronization therewith, Each solenoid 2 of the pressurizing means 20, 30
4, 34 are both turned on as shown in FIG.

Then, the pressure arms 23, 33 are actuated by the solenoids 24, 34 against the biasing forces of the springs 25, 35.
Is rotated to the position shown in the figure by the charging roller 2
The transfer roller 3 and the transfer roller 3 are pressed through the cleaning members 22 and 32, and the rollers 2 and 3 are pressed against the photoconductor 1 at the contact pressure T2. Therefore, the charging roller 2 rotates in the direction of arrow B while contacting the photoconductor 1 rotating in the direction of arrow A with the frictional force "T2. [Mu] 2". Note that μ 2 is a friction coefficient between the charging roller 2 and the photoconductor 1.

At this time, on the surface of the charging roller 2,
Since the cleaning member 22 is also in pressure contact, the friction coefficient between the charging roller 2 and the cleaning member 22 is set to μ.
1. When the contact pressure between the cleaning member 22 and the charging roller 2 is T1, the frictional force that gives the resistance to the rotation in the direction of arrow B by the cleaning member 22 on the charging roller 2. "T1 ・ μ1" works.

However, in this embodiment, the above frictional forces are set to T1.mu.1 <T2.mu.2. Therefore, the charging roller 2 rotates in the arrow B direction and the cleaning member 22 causes the frictional force. The surface of the charging roller 2 is rubbed and cleaned by T1.μ1.

Further, in synchronization with the rotation of the charging roller 2, a charging voltage is applied from the power source 4 (FIG. 1) to the charging roller 2 through the conductive portion 22a of the cleaning member 22, and the charging roller 2 is driven by this voltage. Through the surface 1a of the photoconductor 1
Are uniformly charged. On the other hand, the transfer roller 3 pressed against the photoconductor 1 at the same timing as the charging roller 2 rotates in the arrow C direction while contacting with the frictional force “T2 · μ2”.

At this time, since the cleaning member 32 is also pressed against the surface of the transfer roller 3 at the contact pressure T1, when the friction coefficient between the transfer roller 3 and the cleaning member 32 is μ1, the transfer A frictional force "T1 .mu.1" acts on the roller 3 by the cleaning member 32 to give a resistance to the rotation in the arrow C direction.

However, in this embodiment, the frictional forces are set to T1.mu.1 <T2.mu.2, so that the transfer roller 3 rotates in the direction of arrow C and the cleaning member 32 causes the frictional force T1.・ Clean the surface of the transfer roller 3 by rubbing with μ 1. Further, in synchronization with the rotation of the transfer roller 3, a transfer voltage is applied to the transfer roller 3 from the power source 5 (FIG. 1) via the conductive portion 32a of the cleaning member 32.

As described above, the cleaning members 22 and 32 are provided with the cleaning portions 22b and 32b on the upstream side in the respective rotation directions of the charging roller 2 and the transfer roller 3, and the conductive portions 22a and 32a on the downstream side. Since the toner is adhered to the surfaces of the charging roller 2 and the transfer roller 3 because they are provided, the surfaces are cleaned by the cleaning units 22b and 32b, and the toners are removed to clean the surface. Since the conductive portions 22a and 32a are brought into contact with each other and the charging voltage and the transfer voltage are applied thereto, the voltage is surely applied.

The timing at which the transfer voltage is applied to the transfer roller 3 via the conductive portion 32a of the cleaning member 32 is the timing at which the transfer paper is conveyed to the contact portion between the transfer roller 3 and the photosensitive member 1. There is.

As described above, in this electrostatic copying machine, the conductive parts 22a, 3 having the conductivity of the cleaning members 22, 32 are provided.
Since a voltage is applied to 2a, electrical conduction can be made more reliable than a configuration in which a voltage is applied to a core metal that is the shaft portion of the charging roller found in the conventional contact type charging device.

By the way, in this embodiment, the charging roller 2
The transfer roller 3 is arranged at a position which is point-symmetric with respect to the rotation center of the photosensitive member 1. Therefore, the photosensitive member 1 is pressed by the charging roller 2 and the transfer roller 3 in a symmetrical position with respect to the center thereof in a well-balanced manner, so that a position other than the symmetrical position is pressed in a specific direction. Since the force to be moved is not applied, an excessive load is not applied to the bearing portion that rotatably supports it, so that stable rotation can always be performed.

Further, in this embodiment, the pressurizing means 20 and 3 are used.
0 serves both as a mechanism for pressing the charging roller 2 and the transfer roller 3 against the photoconductor 1 and a mechanism for pressing the cleaning members 22 and 32 against the surfaces of the charging roller 2 and the transfer roller 3. The parts can be simplified, the cost can be reduced, and the reliability is improved.

FIG. 3 is a schematic view showing an embodiment of a pressurizing means for driving the charging roller and the transfer roller by one solenoid to pressurize the photoconductor, and the portions corresponding to those in FIG. Is attached. This pressurizing means 50 has a long hole formed at one end of each pressurizing arm 51, 52, a pin 53 is movably fitted in each long hole, and the pin 53 is fixed to the movable shaft of the solenoid 24. is doing.

Therefore, when the solenoid 24 is turned on, the pressurizing arms 51 and 52 are moved to the shafts 11 and 1, respectively.
1 is used as a fulcrum to oscillate in the directions D and E, and the charging roller 2
The transfer roller 3 is pressed against the photoconductor 1 via the cleaning members 22 and 32. By doing so, the number of parts can be further reduced and the configuration can be simplified, so that the cost can be further reduced.

FIG. 4 is a schematic view showing an embodiment of a pressing means capable of keeping both the charging roller and the transfer roller away from the photosensitive member, and the portions corresponding to those in FIG. There is. The pressurizing means 60 and 70 connect the roller support arms 61 and 71 to the shafts 12 and 12 at one end thereof, respectively.
The springs 25 and 35 for urging the charging roller 2 and the transfer roller 3 in a direction of separating the charging roller 2 and the transfer roller 3 from the photoconductor 1 are attached to the other ends thereof.

When the solenoids 24, 34 of the pressure applying means 60, 70 are turned on, the pressure applying arm 6 is pressed.
2, 72 swing around the shaft 11 as a fulcrum, and the charging roller 2 and the transfer roller 3 move to the cleaning members 22 and 3 respectively.
The photoconductor 1 is pressed against each other via 2.

Further, when the solenoids 24 and 34 are turned off, the pressure arms 62 and 72 cause the springs 25 and 3 to move.
Since it is returned by the biasing force of 5, the charging roller 2 and the transfer roller 3 are completely separated from the photoconductor 1. According to this embodiment, since the charging roller 2 and the transfer roller 3 are both completely separated from the photoconductor 1 when the copying operation is not performed, the surfaces of the charging roller 2 and the transfer roller 3 can be made more difficult to be contaminated. it can.

Since the cleaning members 22 and 32 in each of the above embodiments are separated into the conductive portions 22a and 32a and the cleaning portions 22b and 32b, respectively, the reliability of both is improved. In addition, the cleaning member 2
In order to maintain the performance of 2, 32, the conductive portions 22a, 32a
Alternatively, it is convenient because only one of the cleaning units 22b and 32b can be replaced.

By the way, there is a conventional apparatus in which a charging roller made of a rubber material (for example, EPDM) is left for a long time while being pressed against a photosensitive member even when the apparatus is not used for a while. It was In that case, the plasticizer contained in the rubber material oozes out to locally change the surface of the photoconductor to cause abnormal images such as white spots.

However, in each of the embodiments shown in FIGS. 1 to 3, when the copying operation is not performed, the charging roller 2 only comes into light contact with the photosensitive member 1 only by its own weight, so that such an abnormal image may occur. There is no.

Further, since the transfer roller 3 having the elastic portion is separated from the photoconductor 1 by its own weight when the copying operation is not performed, the transfer roller 3 is long-pressed with the photoconductor 1 strongly. When left for a time, the photoconductor 1
There is a case where permanent contact is locally generated in the contact area with, and uneven transfer occurs due to that, and a clear image cannot be obtained, but a high-quality image without such a worry can be obtained. .

Further, the cleaning members 22 and 32
Is a charging roller 2 and a transfer roller 3 during cleaning.
Of the charging roller 2 and the transfer roller 3 which are rotated by being pressed against the surfaces of the charging rollers 20 and 30 (pressing means 50 in the embodiment of FIG. 3) by the frictional force T1.μ1. Since cleaning is performed, the cleaning property is good.

Further, the cleaning members 22 and 32
During the periods other than the charging operation and the transfer operation, the pressing means 20 and 30 are in the non-pressurized state, so that the surfaces of the charging roller 2 and the transfer roller 3 are separated from each other or come into contact with each other by their own weight, and thus rotate. Since no load fluctuation is applied to the photoconductor 1, the photoconductor 1 rotates in a stable state with little speed fluctuation, so that a high-quality image can be obtained.

Further, in each of the above-described embodiments, the charging roller 2 and the transfer roller 3 are in contact with the photoconductor 1 without having its own rotation driving means, and are rotated together by the photoconductor 1 due to the frictional force therebetween. , It's that simple.

[0063]

As described above, according to the present invention, the charging roller and the transfer roller can be brought into pressure contact with the photoconductor by simply pressing the charging roller and the transfer roller through the cleaning member, and in that state. Since both the charging roller and the transfer roller can be cleaned, uneven charging and uneven transfer can be prevented, and a stable image can be obtained for a long period of time.

Moreover, since the pressing means has both a mechanism for pressing the charging roller and the transfer roller against the photosensitive member and a mechanism for pressing each cleaning member against these rollers, the whole is relatively simple. It can be configured in various ways.

Further, since a voltage is applied to the charging roller and the transfer roller from the power source through the conductive portion of each cleaning member, a voltage is applied to the core bar portion which is the conventional shaft portion as compared with the conventional configuration. It is possible to make electrical conduction more reliable when a voltage is applied to the charging roller and the transfer roller, and to improve reliability.

Further, if the charging roller and the transfer roller are arranged point-symmetrically with respect to the center of rotation of the photosensitive member, the photosensitive member is pressed at a position symmetrical with respect to the center by the charging roller and the transfer roller in a well-balanced manner. Therefore, unlike the case where pressure is applied to a position other than the symmetrical position, a force that moves in a specific direction does not act, so that stable rotation can always be performed and a stable image can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic view showing a state near a photoconductor when an electrostatic copying machine which is an image forming apparatus according to an embodiment of the present invention is not copying.

FIG. 2 is a schematic view showing a state in the vicinity of a photoconductor during a copying operation of the electrostatic copying machine.

FIG. 3 is a schematic view showing an embodiment of a pressing unit that drives a charging roller and a transfer roller with a single solenoid to press the photosensitive member.

FIG. 4 is a schematic view showing an embodiment of a pressurizing unit capable of keeping both the charging roller and the transfer roller in a state of being separated from the photosensitive member.

[Explanation of symbols]

 1: Photoconductor 1a: Surface 2: Charging roller 3: Transfer roller 4,5: Power supply 20, 30, 50, 60, 70: Pressurizing means 22, 32: Cleaning member 22a, 32a: Conducting part

Claims (2)

[Claims] 1. A rotating photoconductor, a charging roller and a transfer roller which rotate in contact with the surface thereof, respectively, a power supply for applying a voltage to each roller, and a cleaning member for cleaning the surface of each roller. In an image forming apparatus including: a cleaning member, which is in contact with the charging roller and the transfer roller, is provided with a conductive portion having conductivity.
A voltage is applied from the power source to the charging roller and the transfer roller through the respective conductive portions, and the charging roller and the transfer roller are pressed through the cleaning members so as to be brought into pressure contact with the photoconductor, respectively. An image forming apparatus comprising a pressure unit. 2. The image forming apparatus according to claim 1,
An image forming apparatus, wherein the charging roller and the transfer roller are arranged at positions symmetrical with respect to a rotation center of the photoconductor.