JPH0895351A - Image forming device - Google Patents

Abstract

(57) [Abstract] [Purpose] While suppressing the cost increase associated with cleaning the contact charging means, simplifying the cleaning work when an abnormality occurs. [Structure] A charging roller of the housing portion 9 of the cartridge.
An opening 6 for cleaning is provided at a position facing the roller 3, and the charging roller 3 is movably supported at a charging position in contact with the photosensitive drum 2 and a cleaning position apart from the charging position. A transparent cover 10 is installed in the opening. The guide hole for supporting the shaft 3a is formed in an inverted L shape to realize the holding at the cleaning position. Stopper mechanism 11
Is provided to prevent the charging roller 3 from dropping and colliding.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus,
In particular, the present invention relates to an image forming apparatus provided with a charging roller for contacting and charging a photoconductor in a small cartridge.

[0002]

2. Description of the Related Art A photosensitive layer on the surface of an image bearing member is uniformly charged by a charging means, optical image information is applied to the photosensitive layer to form an electrostatic latent image, and usually powdery toner is supplied to the electrostatic latent image. An image forming apparatus that repeats the process of electrostatically transferring the toner image onto a sheet-like transfer paper after visualizing the latent image has been widely used as a copying machine, a facsimile, a printer, etc. It is well known that this is done.

In the image forming process using the photoconductor as described above, as a means for charging the photoconductor, a charger in which a metal wire is spread is generally used, and a direct current of about 5 to 8 KV is applied to the metal wire. In many cases, the photoreceptor is charged by corona discharge generated by applying a high voltage. However, this type of means generates ozone and nitrogen oxides associated with corona discharge, which may damage the photoconductor itself or adhere to the ozone and cause deterioration of image quality. As for the flow itself, there is a problem that the amount of flow in the direction of the photoconductor is as small as 5 to 30% and the efficiency is low.

In order to avoid such a drawback, a direct charging system has been proposed in which a charging member is brought into direct contact with a photosensitive member. As the direct charging method, a technique has been proposed in which a charging roller, a belt, or the like is brought into contact with a photoconductor and a DC voltage or a voltage obtained by superimposing an AC on a DC is applied to these charging members.

However, in this type of system, since the charging member is in direct contact with the photosensitive member, toner, paper dust, etc. are likely to adhere, resulting in poor image quality (charging potential corresponding to the adhesion position). There is a possibility that white spots, etc.) may occur due to deterioration of

Therefore, for example, in Japanese Patent Laid-Open No. 2-301777, it is proposed to clean the contact charging member (charging belt made of medium resistance conductive rubber) with a cleaning means (roller, pad) made of felt material. .

By the way, in a recent relatively small-sized image forming apparatus, a cartridge having a main element of an image forming process, for example, a photoconductor, a charger, a developing unit, a cleaning unit, etc., is formed, In many cases, it is configured to be attachable to and detachable from the apparatus body.

For example, in Japanese Patent Laid-Open No. 3-130787, a photoreceptor and the like are built in a cartridge. Also,
The contact charging means is installed on the main body side of the apparatus, and the contact charging means is configured to be contactable with and separated from the photoconductor. Further, means for cleaning the contact charging means is also provided.

[0009]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
The apparatus of Japanese Patent Publication No. 7 is provided with a cleaning means for cleaning the contact charging member, but if this kind of cleaning means is provided, it is inevitable that the apparatus cost will increase. Further, if a contacting / separating mechanism for separating the contact charging means from the surface of the photosensitive member is installed, the cost further increases.

In the case of a low CV machine, the degree of soiling of the contact charging member is relatively small, and it takes a considerable time for ordinary soiling during machine use to accumulate and appear as a defect on an image. Therefore, the merit of mounting the cleaning means at high cost cannot be obtained.

However, if an abnormality occurs in the photosensitive member cleaning section, such as when the cleaning blade is caught with paper dust, the contact charging means may be significantly soiled. When the contact charging means becomes dirty,
If there is no means for cleaning it, there is no cleaning method other than disassembling and cleaning the apparatus, and especially when the contact charging means is incorporated in the cartridge, disassembly is extremely difficult. It takes a lot of work.

Therefore, according to the present invention, the main components for image formation are built in the cartridge, and the cost is low and the CV is low.
In an image forming apparatus of a machine, it is an object to suppress an increase in cost associated with cleaning of a contact charging unit and to simplify a cleaning operation when an abnormality occurs.

[0013]

In order to solve the above problems, according to the present invention, at least an image carrier (2) and a contact charging member (3) for contacting the surface of the image carrier and performing a charging process.
In an image forming apparatus in which a cartridge (1) integrally configured with the cartridge is detachably installed in a main body of the apparatus, a contact charging member is provided at a position of the housing portion (9) of the cartridge facing the contact charging member. A support means (7) provided with a cleaning opening (6) for movably supporting the contact charging member at a charging position in contact with the image carrier and a cleaning position away from the image carrier.
To provide.

According to the second aspect of the present invention, a cover member (10) that can be opened and closed is installed in the opening (6) for cleaning the contact charging member.

Further, in the invention of claim 3, at least a part of the cover member (10) which can be opened and closed is formed of a light-transmissive material.

Further, in the invention of claim 4, a position holding mechanism (7Ba) for holding the contact charging member at the cleaning position is provided.

Further, according to the invention of claim 5, a stopper mechanism (11, 12, 13) for preventing a collision between the image carrier and the contact charging member is engaged with a supporting portion of the contact charging member. To install.

The symbols shown in parentheses are reference numerals of corresponding elements in the embodiments described later, but each constituent element of the present invention is a specific element in the embodiments. It is not limited to only.

[0019]

In the present invention, the contact charging member can be moved to the cleaning position away from the image carrier,
Further, since the opening (6) is formed in the housing portion (9) at a position facing the contact charging member, it is not necessary to disassemble the cartridge even if the contact charging member becomes dirty, and the opening (6) is formed. The contact charging member can be easily cleaned by, for example, manually.

In the second aspect, since the opening (6) for cleaning the contact charging member has the cover member (10) which can be opened and closed, the cover member is closed when the opening (6) is not used. Therefore, it is possible to prevent the charging member from being contaminated due to the intrusion of foreign matter such as toner from the opening.

Further, in the present invention, since at least a part of the cover member (10) which can be opened and closed is made of a light-transmissive material, the surface condition (dirt) of the contact charging member can be maintained even when the cover member is closed. The condition) can be visually confirmed.

Further, in the present invention, since the position holding mechanism (7Ba) for holding the contact charging member at the cleaning position is installed, the contact charging member is manually operated when cleaning the contact charging member. You do n’t have to keep it
Cleaning work becomes easier.

Further, in the present invention, the stopper mechanism (11, 1) is provided at a position where it engages with the support portion of the contact charging member.
2) and 13) are installed, the stopper mechanism prevents the contact charging member from dropping even if the contact charging member comes off the hand when the contact charging member is lifted by hand and cleaned. This prevents the image carrier from colliding with the contact charging member. Therefore, there is no fear of damaging the image carrier and the contact charging member.

[0024]

FIG. 1 shows a vertical cross section of an image forming cartridge 1 of an image forming apparatus according to an embodiment. The image forming cartridge 1 is configured to be attachable / detachable to / from a main body of an image forming apparatus (not shown), and the image forming cartridge 1 includes all main components of the image forming process. That is, inside the image forming cartridge 1, there are installed a photosensitive drum as an image carrier, a charging roller 3 as a contact charging member, a developing device 4, and a cleaning device 5.

The photosensitive drum 2 is rotationally driven in the direction of the arrow at a predetermined peripheral speed, and an image is formed on the surface thereof. The charging roller 3 is pressed against the surface of the photoconductor drum 2 with a predetermined pressing force by the force of the pressure spring 8 shown in FIG. 2, and rotates around with the rotation of the photoconductor drum. A voltage is applied to the charging roller 3 by a power source (not shown), and the surface of the photoconductor drum 2 is uniformly charged to a predetermined high potential by contact with the charging roller 3.

The surface of the charged photosensitive drum 2 is irradiated with light corresponding to an image, whereby a potential distribution corresponding to the image, that is, an electrostatic latent image is formed. This electrostatic latent image is visualized by adhesion of a toner as it passes through the developing device 4, and this toner image is transferred to a predetermined recording sheet.

After the toner image is transferred, foreign matters such as toner and paper dust remaining on the surface of the photosensitive drum 2 are captured and removed by the cleaning device 5, so that the toner is usually placed at the position of the charging roller 3. Does not reach and the charging roller 3 is not soiled. However, in rare cases, foreign matter such as toner or paper dust may pass through the cleaning device 5, reach the position of the charging roller 3, and adhere to the surface thereof.

As shown in FIG. 2, the charging roller 3 is usually used.
Are pressed against the photoconductor drum 2 by the force of the pressure spring 8 and are rotated around as the photoconductor drum 2 rotates. For this reason, the surface of the charging roller 3 is gradually soiled, and the charging ability of the charging roller 3 gradually decreases. Further, if an abnormality occurs such that the blade of the cleaning device 5 bites the paper dust, the surface of the charging roller 3 becomes dirty in a relatively short period of time. Contamination of the charging roller 3 leads to deterioration of image quality. Therefore, when the charging roller 3 is contaminated, it is necessary to clean it.

In this embodiment, both ends of the shaft 3a of the charging roller 3 are rotatably supported by guide holes 7 provided in the housing 9 of the cartridge 1. Further, since the guide hole 7 is formed in the shape of an elongated hole, the charging roller 3 can move in the vertical direction. That is, the charging roller 3 can be lifted by holding both ends of its shaft 3a by hand, and the charging roller 3 is in contact with the photosensitive drum 2 along the guide hole 7 (charging position: solid line). (State shown)
And a position away from the photosensitive drum 2 (cleaning position: a state shown by a virtual line).

In the housing 9 of the cartridge 1, a position facing the charging roller 3 (above the charging roller).
The opening 6 is formed in the. Therefore, the charging roller 3
Is lifted and moved to the cleaning position, a part of the charging roller 3 is exposed from the opening 6, so that the surface of the charging roller 3 can be cleaned in this state. After cleaning, slowly charge roller 3
If you lower the photoconductor drum 2 along the guide hole 7,
Move to the position where it is pressed. Then, the charging roller 3
Returns to the state of charging the photosensitive drum.

FIG. 3 shows the configuration of a modified embodiment corresponding to FIG. Referring to FIG. 3, in this embodiment, an opening 6 provided in the housing 9 of the image forming cartridge 1 is provided with a cover 10 that can be opened and closed. Normally, the cover 10 is closed to prevent foreign matter such as floating toner from entering through the opening 6. When cleaning the charging roller 3, the cover 10 can be opened and the cleaning operation can be performed as described above.
The foreign matter is prevented from entering again by closing. In this embodiment, since the cover 10 is made of a light-transmissive material, it is possible to visually check the degree of dirt on the surface of the charging roller 3 even when the cover 10 is closed. Can be easily determined.

The configuration of another modified embodiment is shown in FIG. In this embodiment, the guide holes 7B supporting both ends of the charging roller 3 are formed in an inverted L shape, and the engaging portion 7Ba extending laterally from the upper portion of the guide hole 7B is the shaft 3a of the charging roller 3. Can be engaged with. That is, when the charging roller 3 is lifted and the shaft 3a is moved to the engaging portion 7Ba in order to clean the charging roller 3, the shaft 3a is engaged with and held by the engaging portion 7Ba, so that a person is charged. The charging roller 3 is held at a predetermined cleaning position (the position indicated by the solid line in FIG. 4) even without holding the. Therefore, the cleaning work becomes easier.

FIG. 5 shows the configuration of yet another modified embodiment. In this embodiment, a stopper mechanism 11 is provided to prevent the charging roller 3 from dropping and colliding with the photosensitive drum. The stopper mechanism 11 is assembled to the image forming cartridge 1 by fastening means (not shown), and includes a stopper shaft 12 and a stopper pressing spring 13. As shown in FIG. 5A, when the charging roller 3 is in the position of contacting the photosensitive drum 2, the front surface of the tip portion 12a of the stopper shaft 12 contacts the shaft 3a of the charging roller 3 and the stopper shaft 12 Is pushed by the shaft 3a and retracted to the left side in the figure.

Then, when the charging roller 3 is lifted to the cleaning position in order to perform the cleaning, as shown in FIG.
As shown in (b), the front surface of the tip portion 12a of the stopper shaft 12 no longer contacts the shaft 3a of the charging roller 3, so that the stopper shaft 12 is pushed to the right side in the figure by the force of the stopper pressing spring 13. In that state, the tip end portion 12a of the stopper shaft 12 is connected to the charging roller 3
Since the shaft 3a is disposed below the shaft 3a, the shaft 3a does not move below the stopper shaft 12. Therefore, the charging roller 3
Even if you inadvertently release the charging roller 3 while lifting it by hand and cleaning it, the charging roller 3
Stops at the position of the stopper shaft 12, so see Fig. 5 (a).
The charging roller 3 does not fall to the state shown as
Since no collision occurs with the photosensitive drum 2, it is possible to prevent both (or one) from being damaged. After the cleaning operation is completed, if the stopper shaft 12 is manually grasped and retracted, the state shown in FIG. 5A can be restored.

[0035]

According to the present invention, the contact charging member can be moved to a cleaning position away from the image carrier, and the opening (6) is formed in the housing portion (9) facing the contact charging member. ) Is formed, it is not necessary to disassemble the cartridge even if the contact charging member becomes dirty, and the contact charging member can be easily cleaned through the opening (6), for example, manually. .

In the second aspect, since the opening (6) for cleaning the contact charging member has the cover member (10) which can be opened and closed, the cover member is closed when the opening (6) is not used. Therefore, it is possible to prevent the charging member from being contaminated due to the intrusion of foreign matter such as toner from the opening.

In the third aspect, since at least a part of the cover member (10) which can be opened and closed is formed of a light-transmissive material, the surface state (dirt) of the contact charging member can be maintained even when the cover member is closed. The condition) can be visually confirmed.

Further, in the present invention, since the position holding mechanism (7Ba) for holding the contact charging member at the cleaning position is installed, the contact charging member is manually operated when cleaning the contact charging member. You do n’t have to keep it
Cleaning work becomes easier.

According to a fifth aspect of the present invention, the stopper mechanism (11, 1) is provided at a position where it engages with the support portion of the contact charging member.
2) and 13) are installed, the stopper mechanism prevents the contact charging member from dropping even if the contact charging member comes off the hand when the contact charging member is lifted by hand and cleaned. This prevents the image carrier from colliding with the contact charging member. Therefore, there is no fear of damaging the image carrier and the contact charging member.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing an image forming cartridge 1 of an apparatus of an embodiment.

FIG. 2 is an enlarged cross-sectional view showing a part of FIG.

FIG. 3 is a sectional view of a portion corresponding to FIG. 2 of the first modified example.

FIG. 4 is a sectional view of a portion corresponding to FIG. 2 of the second modified example.

FIG. 5 is a sectional view of a portion corresponding to FIG. 2 of the third modified embodiment.

[Explanation of symbols]

1: Image forming cartridge 2: Image carrier 3: Charging roller 3a: Shaft 4: Developing device 5: Cleaning device 6: Opening 7,7B: Guide hole 8: Pressure spring 9: Housing 10: Cover 11: Stopper mechanism 12: Stopper shaft 13: Stopper pressure spring

Claims (5)

[Claims] 1. An image forming apparatus in which a cartridge integrally including at least an image carrier and a contact charging member for contacting a surface of the image carrier to perform a charging process is detachably mounted on a main body of the apparatus. In the housing portion of the cartridge, an opening for cleaning the contact charging member is provided at a position facing the contact charging member, and the contact charging member is in contact with the image carrier, and a charging position; At the cleaning position away from the carrier,
An image forming apparatus comprising: a supporting unit that movably supports the image forming apparatus. 2. The cover member that can be opened and closed is installed in the opening for cleaning the contact charging member.
The image forming apparatus described. 3. The image forming apparatus according to claim 2, wherein at least a part of the cover member that can be opened and closed is formed of a light transmissive material. 4. The image forming apparatus according to claim 1, further comprising a position holding mechanism for holding the contact charging member at the cleaning position. 5. The image forming apparatus according to claim 1, wherein a stopper mechanism for preventing a collision between the image carrier and the contact charging member is installed at a position where the stopper mechanism is engaged with a support portion of the contact charging member. .