JP2853208B2 - Image forming device - Google Patents

Description

The present invention relates to an image forming apparatus such as an electrophotographic copying machine, a laser beam printer, and an electrostatic recording device.

More specifically, the present invention relates to an image forming apparatus for forming an image by an image forming process including a step of charging an image carrier surface such as an electrophotographic photosensitive member or an electrostatic recording dielectric.

(Prior Art) In this type of image forming apparatus, a corona charging device has been widely used as a means for charging a surface of an image carrier such as a photoreceptor. The corona charging device is effective as a means for performing a uniform charging process.

 However, there were the following problems.

In order to set the charging potential of the photoreceptor to, for example, 500 to 800v, 4
A high pressure, such as ~ 8 kv, must be applied.

Most of the discharge current from the discharge wire flows to the shield, and only a few percent of the total discharge current is used to charge the photoreceptor surface to a predetermined potential. That is, power efficiency is poor.

Corona products such as ozone are generated by corona discharge, and oxidation of device components and deterioration of the photoreceptor surface due to ozone are likely to occur. The ozone absorption / decomposition filter and a fan that is a means for generating airflow to the filter are provided. It is necessary to arrange such as.

Image unevenness due to discharge wire contamination is likely to occur.

Therefore, contact charging in which a voltage is applied or a charging member for frictional charging is brought into contact with the surface to be charged to perform a charging process (including a static elimination process) instead of a corona discharge device, as a means for charging the surface of the member to be charged such as a photoconductor Means are attracting attention.

In particular, a charging member (roller type,
A contact charging method (or a direct charging method) in which a web type, a blade type, a rod type, a block type, a pad type, a brush type, etc. are brought into contact with a surface to be charged and charged to a predetermined potential. In addition, the applied voltage required to obtain a desired charging potential can be reduced, and the amount of ozone generated during the charging process is extremely small, eliminating the need for an ozone filter. It has advantages such as simplification of configuration, simplicity of configuration, etc., and many research and development proposals for its practical use have been made (JP-A-57-178267, 56-104351, 58-40566 ・ 58
No. 139156 / 58-150975).

The present applicant also applies a DC voltage and an oscillating voltage of twice or more of the charging start voltage of the member to be charged (a voltage whose voltage value changes periodically with time) to the charging member for the purpose of uniform charging processing without charging unevenness. Various proposals have been made, such as applying a superimposed voltage to the charged member and using a multi-layer structure of the charged member in order to eliminate abnormal discharge and dielectric breakdown from the charged member to the member to be charged (Japanese Patent Application No. Sho 61). −298419 ・ 62−230334).

On the other hand, as one of the configuration forms of the image forming apparatus, there is a process cartridge detachable type. This involves at least some image forming means such as an image carrier such as a photoconductor, generally an image carrier, a charging means for the image carrier, a developing means and a cleaning means for the image carrier. A common cartridge cover (cartridge frame, housing) assembled in such a manner as to maintain a predetermined positional relationship with each other, and these are collectively assembled to the image forming apparatus main body so that even a layman can easily and easily perform detachable and replaceable operations. It is.

The process cartridge detachable type is, in principle, used when a specified number of sheets (for example, 3000 to 5000 sheets) have been used for image formation, and is replaced with a new process cartridge on the assumption that the service life has expired. Maintenance is free, the operability and handling of the image forming apparatus is improved, and multi-color images can be formed by replacing and using several process cartridges with different colors of the stored developer. Since it has advantages, it has been put to practical use as one configuration mode of an image forming apparatus such as a personal type small and simple model.

In such an image forming apparatus of the detachable type with a process cartridge, the above-described voltage is applied or a charging member for frictional charging (hereinafter referred to as a contact member) as a charging means for charging an image carrier such as a photoconductor contained in the process cartridge. If a means for charging by contacting the charging member with the image carrier is adopted, an image forming apparatus of a simpler type than when a corona discharge device is used can be constructed.

In this case, since the contact charging member is a durable and long-life member which can be used repeatedly for a long period of time, this member is not provided on the process cartridge side which is a disposable side, and is used on an image forming side which is a durable use side. It is advantageous to arrange and arrange on the apparatus main body side to simplify the configuration of the process cartridge and to reduce the cost.

(Problems to be Solved by the Invention) One of the problems when the contact charging member is arranged and provided on the image forming apparatus main body side as described above is a problem of cleaning the contact charging member.

That is, although the contact charging member itself is a durable and long-life member which can be used repeatedly for a long period of time as described above, the developer (toner) scattered from the developing section and comes out of the transfer paper during repeated use Since foreign matters such as paper dust and other dust and dirt from the outside adhere and gradually accumulate and become dirty, which causes a charging failure, it is better to provide a cleaning member for the contact charging member. Good.

When the cleaning member is always in contact with the contact charging member and is provided on the image forming apparatus main body side, it is difficult to maintain the cleaning ability of the cleaning member until the life of the contact charging member, that is, the life of the image forming apparatus main body. ,
A simple cleaning member is not sufficient, resulting in poor cleaning.

If the cleaning member is periodically removed from the image forming apparatus body and replaced with a new one, the maintenance-free advantage of this type of image forming apparatus is lost.

Further, in the case of a configuration in which the cleaning member is always in contact with the contact charging member, when the contact charging member is in the form of a rotating body such as a rotating roller or a rotating belt (hereinafter referred to as a charging roller), the charging roller is In the case of a roller in which the configuration of the charging roller is particularly composed of two or more layers, which causes abrasion,
The outermost layer may be provided with a protective layer having a thickness of about 10 μm to several tens of μm. If the amount of wear is large, this layer may not function as a protective layer. Further, in order to obtain uniform charging, it is desirable that the surface roughness of the charging roller is small. Therefore, if the surface is roughened by constant cleaning, there is a disadvantage that uneven charging is likely to occur.

In the case of a contact charging member of a blade type, a pad type, a block type or the like, it is impossible to clean the member while charging the member to be charged by contacting the member.

The present invention rationally solves such a problem of cleaning the image forming apparatus and constitutes a durable, reliable, simple and low-cost type of process cartridge detachable / contact charging type image forming apparatus. This is especially possible.

(Means for Solving the Problems) The present invention is an image forming apparatus that performs image formation by an image forming process unit including a step of performing a charging process on a surface of an image carrier. The carrier is configured as a process cartridge detachable from the main body of the image forming apparatus. The means for charging the surface of the image carrier is provided in the main body of the image forming apparatus, and the process mounted on the main body of the image forming apparatus. A contact charging member that contacts the image carrier surface of the cartridge to charge the image carrier surface, has a cleaning member for the contact charging member, and has contact / separation control means between the contact charging member and the cleaning member. An image forming apparatus characterized in that:

Further, the present invention is characterized in that, in the above-mentioned apparatus, the contact charging means is a rotating body, and the cleaning of the rotating body by contact with the cleaning member is performed at least one rotation while the rotating body is in contact with the cleaning member. Image forming apparatus.

(Operation) By providing a contact charging member and a cleaning member for the member on the image forming apparatus main body side which is a durable use side, it is possible to provide a detachable and replaceable process cartridge for the image forming apparatus main body. Simplified configuration
The size and cost can be reduced.

The cleaning of the contact charging member by the contact between the contact charging member and the cleaning member is not performed by always bringing both members into contact with each other. During the period, the two members are kept in non-contact, so that the cleaning time when the two members are brought into contact is practically short, and the cleaning execution interval can be actually lengthened.

Therefore, damage such as wear and surface roughness due to the contact of the contact charging member with the cleaning member is more reduced than when the contact charging member and the cleaning member are always in contact.
It can greatly reduce the durability (use life) of the contact charging member, and can keep the contact charging member surface clean at all times to maintain stable and good charging performance over a long period of time. Can be.

In addition, since the total time of contacting the cleaning member during the durability period of the contact charging member is short, a simple and low-cost cleaning member can be used for a long period of time.

Even when the charging member is of a blade type, a pad type, a block type or the like, cleaning can be performed by making contact with the cleaning member when the charging member is not in contact with the image carrier.

Thus, the above-mentioned problem of cleaning of the contact charging member is solved, and a durable, reliable, simple, and low-cost image forming apparatus of this type that fully utilizes the advantages of the process cartridge detachable type and the contact charging type. Can be configured.

Example 1 Example 1 (FIGS. 1 and 2) FIG. 1 shows a process cartridge detachable type according to the present invention.
1 shows a schematic configuration of an example of a contact charging type image forming apparatus (electrophotographic copying machine).

Reference numeral 100 denotes a general reference number of the process cartridge, which can be freely attached to and detached from a predetermined storage portion in the copying machine main body by a conventionally known appropriate method. The figure shows a state in which it is mounted.

The cartridge 100 according to the present embodiment includes three devices of an electrophotographic process device, that is, a rotating drum type electrophotographic photosensitive member (hereinafter, referred to as a photosensitive drum) 1 as an image carrier, a developing device 4, and a cleaning device 5. These components are included in a common cartridge frame 12 with a predetermined arrangement relationship with each other, assembled and removably mounted on the copier body at a time.

When the cartridge 100 is mounted in the main body of the copying machine in a predetermined manner, the cartridge 100 is mechanically and electrically coupled to the main body of the copying machine to enable power transmission, power supply, transmission and reception of control signals from the main body of the copying machine, and the like. Become.

2 is a charging roller as a contact charging member, 3 is a short focus imaging element, 15 is a paper feed registration roller, 14 is a transfer roller, 16
Is a paper guide, and these are devices disposed on the copying machine main body side.

When the cartridge 100 is mounted in the copier main body in a predetermined manner, the upper opening 12a of the cartridge 100 is located at a predetermined position corresponding to the portion of the charging roller 2 and the short focus imaging element 3 as shown in FIG. The side opening 12b is the transfer roller 1
The transfer roller 14 comes into contact with the lower surface of the photosensitive drum 1 at a predetermined position corresponding to the portion 4.

The opening 1 on the upper surface side and the lower surface side of the cartridge 100
The shutters 2a and 12b may be provided with an opening / closing shutter member for closing the opening to protect the surface of the photosensitive drum 1 and the inside of the cartridge when the cartridge 100 is removed from the copying machine main body. The shutter member is cartridge 100
It can be configured to open automatically during the mounting and moving process of the copier body, and to automatically close during the removal and moving process, or to be manually opened and closed. it can.

The charging roller 2 of this embodiment has a metal shaft 2c, a medium-resistance rubber layer 2b (for example, EPDM in which carbon is dispersed) of about 105 to ⁷ Ωcm, and a nylon coated on the outer surface thereof. It is composed of a high-resistance thin film layer 2a of 15 μm such as resin.

The charging roller 2 is connected to both ends of the metal shaft 2c by supporting shafts 8a.
The bearing is rotatably held between one arm of a pair of levers 8 on the front side and the back side which are rotatable around the center. Further, conductive bearings 6 are fitted to both ends of the metal shaft 2c, respectively, and a conductive pressure spring 7 is contracted between the conductive bearing 6 and an electrode 13 provided on a stationary member. The lever 8 is constantly urged to rotate about the support shaft 8a in the clockwise direction of the charging roller 2 toward the photosensitive drum 1 by the tension force of 7.

Reference numeral 8b denotes, for example, an electromagnetic solenoid device (hereinafter, referred to as an SL device) as lever swing means. When power is supplied to the SL device 8b, the lever 8 is rotated counterclockwise around the support shaft 8a against the pressure spring 7, so that the charging roller 2 is separated from the surface of the photosensitive drum 1 by a solid line. Shown in the first position. The turning posture state of the lever 8 at this time is set to OFF.

When the power to the SL device 8b is cut off, the counterclockwise rotational urging force on the lever 8 is released, and the lever 8 pivots clockwise around the support shaft 8a by the tension force of the spring 7 to rotate the charging roller. 2
Abuts on the surface of the photosensitive drum 1 with a predetermined pressing force.
It is held at the second position indicated by the dashed line. Lever 8 at this time
Is turned ON.

Reference numeral 9 denotes a charging roller cleaning roller disposed near the charging roller 2, and in this embodiment, a urethane sponge roller. Reference numeral 10 denotes a scraper for scraping dirt and dust from the surface of the cleaning roller 9, and reference numeral 11 denotes a container for storing the dirt and dust scraped off by the scraper 10.

When the lever 8 is turned off and the charging roller 2 is held at a position shown by a solid line separated from the surface of the photosensitive drum 1, the charging roller 2 is brought into contact with the cleaning roller 9 so that the first charging roller 2 contacts the cleaning roller 9. The position and the arrangement position of the cleaning roller 9 are set.

Reference numeral 13a denotes a bias application power source (primary high-voltage bias) for the charging roller 2. In this embodiment, a predetermined superimposed voltage (V _DC + V _AC ) of the DC voltage and the oscillation voltage is supplied from the power source 13a.
But electrode 13 → conductive pressure spring 7 → conductive bearing 6 → metal rod
The voltage is applied to the charging roller 2 via 2c.

Next, the operation of this embodiment will be described with reference to the sequence timing chart of FIG.

. Before the main power switch of the device is turned on and the copy key (copy start key) is turned on, the lever 8 is turned off.
1, the charging roller 2 is separated from the surface of the photosensitive drum 1 as shown by the solid line in FIG.

. When the copy key is turned ON, the charging roller 2 and the cleaning roller 9 are kept in the above-mentioned mutual contact state, and the charging roller 2 is moved clockwise as indicated by an arrow B by driving means (not shown). Are simultaneously and positively driven to rotate in the clockwise direction of the arrow C by driving means (not shown).

As a result, the charging roller 2 and the cleaning roller 9 rub against each other at the mutual contact portion, so that the surface of the charging roller 2 is cleaned by the cleaning roller 9. Dirt, dust and the like adhering from the charging roller 2 side to the cleaning roller 9 side are scraped off from the cleaning roller 9 surface by the scraper 10 and housed in the container 11 to clean the cleaning roller 9.

The above rotation of the roller 2 and the cleaning roller 9 for cleaning the charging roller 2 is carried out for a time t _1. The time t ₁ is charged entire peripheral surface of the roller 2 is a charging roller 2 so that a state of being cleaned to set more than the time required for at least one rotation is desired.

. And the time t ₁ has passed the rotational driving of the charging roller 2 and the cleaning roller 9 becomes OFF, the cleaning period of the charging roller 2 is completed.

. Thereafter, the power to the SL device 8b is cut off, the lever 8 is turned on, and the cleaned charged roller 2 separates from the cleaning roller 9 and comes into contact with the surface of the photosensitive drum 1 as shown by a two-point mirror line in FIG. It is in a state where it is pressed in a predetermined manner by the pressing force of the spring 7.

. Next, the photosensitive drum 1 is rotationally driven at a predetermined frequency in a clockwise direction indicated by an arrow A. The charging roller 2 abutting on the surface of the predetermined drum 1 rotates in a counterclockwise direction indicated by an arrow D as the photosensitive drum 1 rotates.

. Next, a predetermined bias voltage is applied to the charging roller 2 from the power supply 13a. As a result, the peripheral surface of the rotating photosensitive drum 1 is charged (primary charging) to a predetermined surface potential by the charging roller 2.

. Image information exposing means (not shown) and image forming element 3 form target image information L on the charged surface of photosensitive drum 1 to form an electrostatic latent image corresponding to the exposed image on rotating drum 1. It is formed sequentially.

. The formed latent images are sequentially developed as toner images by the developing device 4.

. On the other hand, a transfer material P is fed from a paper feed unit (not shown), and is fed to the transfer unit between the photosensitive drum 1 and the transfer roller 14 by the registration roller pair 15 at an appropriate timing.
The toner image on the photosensitive drum 1 surface side is sequentially transferred to the transfer material P.

. The transfer material P having received the transfer of the toner image is a photosensitive drum 1
After being separated from the surface, it is conveyed to a fixing device (not shown) by a guide 16 and receives an image.

. After the image transfer, the surface of the photosensitive drum 1 is subjected to removal and cleaning of adhered contaminants such as untransferred toner by the cleaning device 5 and then subjected to the charging process of the charging roller 2 again.

. After the completion of the charging step, the bias application to the charging roller is turned off, and thereafter, the power is supplied to the SL device 8b, and the lever 8 is turned off. As a result, the charging roller 2 is separated from the surface of the photosensitive drum 1 and returns to the state shown by the solid line in FIG.

Thereafter, the rotation drive of the photosensitive drum 1 is turned off, the copying operation is completed, and the process stands by until the copy key is turned on next.

As described above, since in the present embodiment apparatus cleaning roller 9 cleans only the charge roller 2 surface of t ₁ during the entire replication process time, compared with that cleans the charging roller 2 always the charging roller 2 Since the time for shaving or roughening the surface is short, the life of the charging roller can be prolonged, and the long-term stability of charging can be realized. Second Embodiment (FIG. 3) In this embodiment, the first embodiment is used. Instead of using the charging roller 2 as the contact charging member in the device (FIG. 1), a charging brush 2A planted in a cylindrical shape was used. Other device configurations are the same. The cleaning sequence of the charging brush 2A may be exactly the same as the cleaning sequence of the charging roller 2 shown in FIG.

However, in the case of the charging brush 2A, it is impossible to follow the rotation by the frictional force with the photosensitive drum 1, so that the charging brush 2A is rotationally driven in the direction of arrow D by a driving unit (not shown) during the charging sequence.

Embodiment 3 (FIG. 4) In this embodiment, the cleaning sequence of the charging roller 2 in the apparatus of the first embodiment (FIG. 1) is different from the sequence of FIG.

That is, the cleaning of the charging roller 2 in FIG. 2 is performed after the copy key is turned on and before the charging step is started. In the case of this example (FIG. 4), the cleaning step is not performed and the charging step is not performed. This is a sequence in which the cleaning step is performed after completion.

In other words, at the end of the entire copying process, after the charging process is completed (after the bias application is turned off), the power is supplied to the SL device 8b, the lever 8 is turned off, and the charging roller 2 is separated from the photosensitive drum 1 surface for cleaning. The roller contacts the roller 9.

Then the cleaning of the charging roller 2 circumferential surface is done by rotating in the C direction of the charging roller 2 of the rotary drive and the cleaning roller 9 in the direction B by a predetermined time t ₁ run.

In this embodiment, the drive of the photosensitive drum 1 is turned off at the beginning of the start of the cleaning process. Rotary drive is OFF elapsed after the charging roller 2 and the cleaning roller 9 time t ₁
And the apparatus is in a standby state until the copy key is turned on next.

In this sequence, the charging roller 2 is separated from the photosensitive drum 1 by turning on the lever before the photosensitive drum drive is turned off.
May be turned on and separated from the photosensitive drum 1.

By providing a cleaning sequence after the charging step as in this embodiment, there is an advantage that copying (first copying) can be started earlier.

The charging roller 2 may become dirty when the process cartridge is inserted into or removed from the copying machine main body. In such a case, the charging process is started only after the cartridge is inserted or removed or only when the main power switch of the apparatus is turned ON. If a cleaning sequence for the charging roller 2 is inserted beforehand, if the cleaning is performed after the completion of the charging process, the charged charging roller 2 having a cleaned surface state can be always used for charging.

Embodiment 4 (FIGS. 5 and 6) The apparatus of this embodiment uses a stationary and fixed cleaning pad 9A in place of the cleaning roller 9 as the cleaning member in the apparatus of FIG. 1 (FIG. 1). is there.

When the lever 8 is OFF, the charging roller 2 is separated from the surface of the photosensitive drum 1 and kept in contact with the cleaning pad 9A as shown by a solid line in FIG. 5, and when the lever 8 is ON, it is shown by a two-dot chain line. As described above, the photosensitive drum 1 is brought into contact with the surface of the photosensitive drum 1 with a predetermined pressing force by a pressure spring, and is separated from the cleaning pad 9A.

FIG. 6 is a timing chart of a cleaning sequence of the charging roller 2 in the apparatus of this embodiment. This example after sequence as well as copy key ON of the aforementioned second illustrated example, for a predetermined time before the start charging step t _1, in a state where the lever 8 is the charging roller 2 is OFF in contact with the cleaning pad 9A When the charging roller 2 is driven to rotate in the direction indicated by the arrow B, the cleaning of the roller 2 is performed.

In the case of the present embodiment, the cleaning pad 9A is a stationary member and does not require a driving means unlike the cleaning roller 9, so that there is an advantage that a simple and inexpensive configuration can be obtained.

Fifth Embodiment (FIGS. 7 and 8) The charging roller 2 of the present embodiment is kept in a state of being constantly in contact with the surface of the photosensitive drum 1 of the cartridge 100 mounted on the apparatus main body by the pressing force of the pressure spring 7, and the photosensitive roller is exposed. The drum 1 rotates following the rotation of the drum 1.

A cleaning pad is attached to the side of the charging roller 2.
9B is provided so as to be freely accessible. That is, 27 is an electromagnetic solenoid device (SL device), and 16 is a lever that can swing freely around a support shaft 16a. The tip of one arm of this lever and the tip of the forward / backward plunger 27a of the SL device 27 are connected. It is rotatably connected by a pin shaft 16b. Also, the tip of the other arm of the lever 16,
A seat member 25a integrally provided at the rear end of the pressure spring 25 and the pin shaft 1
A cleaning pad 9B is integrally provided on the front surface of a seat member 25b which is rotatably connected at 6C and is integrally provided at the tip of the spring 25. The seat member 25b is guided in the forward and backward directions with respect to the side surface of the charging roller 2 along a guide (not shown).

When the SL device 27 is OFF (de-energized), the plunger 27a projects outward of the solenoid by an urging spring (not shown), and the lever 26 is rotated clockwise about the pin shaft 16a to perform cleaning. Pad 9B is charged roller 2 as shown by the solid line.
And is kept out of contact with the roller 2.

When the SL device 27 is ON (energized), the plunger 27a is pulled into the solenoid, whereby the lever 26 is rotated counterclockwise as shown by a two-dot chain line, and the cleaning pad 9B is moved to the side of the charging roller 2. The contact is maintained in a state of contact with a predetermined pressing force by the compression reaction force of the spring 25.

FIG. 8 shows a cleaning sequence of the charging roller 2 in the apparatus of this embodiment. SL device 27 after copy key ON
Is turned on, the cleaning pad 9B comes into pressure contact with the side surface of the charging roller 2, and then the rotation driving of the photosensitive drum 1 is turned on, and the driven rotation of the charging roller 2 occurs, so that the mutual sliding between the roller 2 and the cleaning pad 9B occurs. The cleaning of the roller 2 is started by the rubbing.

The photosensitive rotation drive start of the drum 1, thus the driven rotation starting from a predetermined time of the charging roller 2 t ₁ has elapsed,
When the SL device 27 is turned off and the cleaning pad 9B retreats and separates from the charging roller 2, the cleaning process of the roller 2 is completed.

Next, a bias voltage is applied (ON) to the charging roller 2 by the power supply 13a, and the charging process of the photosensitive drum 1 is started.

In this embodiment, the cleaning sequence is performed before the charging step, but may be performed after the charging step. Also,
In the copy operation, it is not necessary to perform the cleaning sequence each time, and the cleaning sequence may be provided once for a predetermined number of sheets (for example, 100 sheets). This is the same for the apparatuses of the first to fourth embodiments.

Embodiment 6 (FIG. 9) This embodiment uses a blade-type (charging blade) 2B as a contact charging member. Charging blade of this example
2B contacts the photosensitive drum 1 with a predetermined pressing force in the counter direction with respect to the rotation direction of the drum, and a power supply 13a.
Then, a predetermined bias voltage is applied via the blade supporting member 28 to charge the surface of the photosensitive drum 1.

The charging blade 2B cannot be cleaned at the same time as the charging process as compared with other contact charging means such as a charging roller and a charging belt which are rotating bodies. Therefore, even if the cleaning means is provided, it must be released from the charging means. In this embodiment, the charging blade 2B can be moved in the direction indicated by an arrow J in a direction away from the photosensitive drum 1 by moving means (not shown), and is always held at a charging action position indicated by a solid line in contact with the photosensitive drum 1. Have been.

At the time of the cleaning step, the blade is moved to the retracted position indicated by the two-dot chain line, and the blade tip is cleaned by contact with the fur brush 9C as a cleaning member that is rotationally driven.
After the cleaning, the charging blade 2B is returned to the charging operation position shown by the solid line again and moved.

The cleaning sequence is as described in Examples 1 to 5 above.
Are available.

Although the embodiment of the electrophotographic copying machine has been described above, the present invention can be applied to a laser beam scanning exposure type printer, an electrostatic recording apparatus, and other image forming apparatuses utilizing various conventionally known image forming processes.

The image carrier is not limited to the drum type, but may be a belt type, a sheet type,
A traveling web type or the like may be used.

The contact charging member is not limited to a roller type, a brush type, or a blade type, but may be a pad type, a rod type, a block type, or the like. It can also be a contact member for friction charging.

The process cartridge 100 is not limited to the type in which the three process devices of the photosensitive drum 1, the developing device 4, and the cleaning device 5 are included as in the embodiment, and other components including, for example, the photosensitive drum 1 and the cleaning device 5. A desired configuration such as a two-body configuration of the developing device 4 and the developing device 4 can be adopted.

The cleaning member for the contact charging member provided on the image forming apparatus main body side may be provided on the process cartridge side.

(Effect of the Invention) As described above, the process cartridge including at least the image carrier is detachable from the image forming apparatus main body, and the image forming apparatus main body is provided with the contact charging unit and the unit for cleaning the contact charging unit. An image forming apparatus, in which the cleaning means is configured to be releasable from the contact charging means, so that the service life of the contact charging means can be extended.
Stabilization has become feasible, and further downsizing and cost reduction of the process cartridge can be achieved.

[Brief description of the drawings]

FIG. 1 is a schematic view of a device according to a first embodiment. FIG. 2 is an operation timing chart. FIG. 3 is a schematic view of a main part of the second embodiment. FIG. 4 is an operation timing chart of the third embodiment. FIG. 5 is a schematic view of a main part of the device according to the fourth embodiment. FIG. 6 is an operation timing chart. FIG. 7 is a schematic view of a main part of the fifth embodiment. FIG. 8 is an operation timing chart. FIG. 9 is a schematic view of a main part of the device according to the sixth embodiment. 100 is a process cartridge, 1 is a photosensitive drum as an image carrier, 2.2A and 2B are charging rollers, charging brushes and charging blades as contact charging members, 9.9A, 9B and 9C are cleaning rollers as cleaning members. The pad
The same fur brush.

──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Takeo Shoko 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (56) References JP-A-3-15864 (JP, A) JP-A-59 -147376 (JP, A) JP-A-63-292166 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G03G 15/02 G03G 21/10

Claims (2)

(57) [Claims] 1. An image forming apparatus for forming an image by an image forming process means including a step of charging a surface of an image carrier, wherein at least the image carrier in the image forming process means is provided with respect to a main body of the image forming apparatus. The means for charging the surface of the image carrier is provided on the image forming apparatus main body side, and is contacted with the surface of the image carrier on the process cartridge mounted on the image forming apparatus main body. An image forming apparatus, comprising: a contact charging member for charging a surface of an image carrier by charging; a cleaning member for the contact charging member; and means for controlling contact / separation between the contact charging member and the cleaning member. 2. The cleaning device according to claim 1, wherein the contact charging member is a rotating body, and the cleaning of the rotating body surface by contact with the cleaning member is performed at least one rotation while the rotating body is in contact with the cleaning member. The image forming apparatus as described in the above.