JPH07101325B2 - Process cartridge and image forming apparatus to which the process cartridge is detachable - Google Patents

Description

Detailed Description of the Invention a. OBJECT OF THE INVENTION [Industrial field of use] The present invention relates to a process cartridge and an image forming apparatus to which the process cartridge is detachable.

Here, the image forming apparatus is an electrophotographic copying machine, a laser beam printer, or the like.

[Conventional technology]

In recent years, in an image forming apparatus such as an electrophotographic copying machine or a laser beam printer, a bias is used instead of a conventional corona discharger as a means for applying an electric charge onto a photoconductor as an image carrier to form an electrostatic latent image. A roller charging method has been proposed in which the applied roller is brought into contact with the photoconductor.

Compared with the method using corona discharge, this method requires. It is possible to downsize the device. Does not require as high a high voltage power supply as a corona discharger ,. It has the advantage that there is no contamination on the photoconductor by the corona product.

[Problems to be solved by the invention]

However, even in such a roller charging method,
What is needed is a means for removing dirt on the surface of the charging roller.
That is, the scattering of the developer from the developing unit and the dust from the outside
There is no chance that foreign matter such as dust adheres to the charging roller, and when they adhere to the charging roller, charges are not applied to the photoconductor only at that portion, which may result in a non-uniform image.

On the other hand, in this type of image forming apparatus, in order to improve reliability and facilitate operability and maintenance, the photoconductor and the image forming means around the photoconductor are integrally formed and integrally attached to and detached from the apparatus main body. A free process cartridge system is known.

The use of the above roller charging method as the charging means in such a process cartridge has the above-mentioned merits, and the performance can be greatly improved.

However, the charging roller in this process cartridge also has the above-mentioned problem of foreign matter adhesion, and therefore some sort of cleaning means for the surface of the charging roller is required. However, it is not necessary to incorporate the cleaning means into the process cartridge together with the charging roller. However, there is a problem in that the advantages of roller charging are impaired.

Therefore, the present invention relates to a process cartridge and an image forming apparatus to which the process cartridge is attachable / detachable, when a roller charging unit is used as a charging unit of a photoconductor, the charging roller provided in the process cartridge without increasing the size of the process cartridge. The purpose is to be able to easily clean.

B. Structure of the Invention [Means for Solving Problems] The present invention is a process cartridge having the following structure and an image forming apparatus to which the process cartridge is detachable.

(1) A process cartridge detachably mountable to an image forming apparatus main body, comprising: a photoconductor, a roller charging unit for charging the photoconductor, and a frame body containing these. An opening is provided along the roller longitudinal direction of the device, and the roller charging device is provided by exposing a part of the roller peripheral surface from the opening to the outside of the frame along the roller longitudinal direction, and the roller charging device is provided from outside the frame. A process cartridge characterized in that a roller charging means is directly provided with a dial which is manually rotated.

(2) The process cartridge according to item (1), including a developing device for developing the latent image formed on the photoconductor.

(3) The process cartridge according to item (1), further including a cleaning device that cleans the photoconductor.

(4) The image forming apparatus is an electrophotographic copying machine (1)
The process cartridge according to item.

(5) The process cartridge according to item (1), wherein the image forming apparatus is a laser beam printer.

(6) In an image forming apparatus in which a process cartridge is attachable / detachable and forms an image on a recording medium, a photoconductor, a roller charging unit that charges the photoconductor,
A frame body containing these components, and the frame body is provided with an opening along the roller longitudinal direction of the roller charging means, and the roller charging means is provided with a part of the peripheral surface of the roller along the roller longitudinal direction. And a mounting means to which a process cartridge having a dial for manually rotating the roller charging means from the outside of the frame is directly attached to the roller charging means, is detachable, and the recording medium is conveyed. An image forming apparatus comprising: a conveying unit.

(7) The image forming apparatus is an electrophotographic copying machine (6)
The image forming apparatus according to item.

(8) The image forming apparatus according to item (6), which is a laser beam printer.

[Work] When an image defect or the like occurs due to the dirt on the surface of the roller of the roller charging means, the process cartridge is removed from the image forming apparatus. Since the roller surface is exposed to the outside through the opening, the roller surface can be easily and reliably cleaned by the cleaning member in the roller exposure opening, and the dial is rotated to operate the roller peripheral surface portion. It is possible to easily inspect and clean the entire circumference of the roller by exposing the rollers to the outside through the opening and cleaning them with a cleaning member, and you can always obtain good and stable images with simple maintenance operations. It will be possible.

． Since the manual rotation operation of the roller charging means is performed by directly providing the roller charging means with a dial for manual rotation and rotating the dial, the roller of the roller charging means can be easily operated with a light torque. The smooth manual rotation operation allows quick and efficient cleaning of the entire circumference of the roller.

． Since the roller cleaning means is not incorporated in the process cartridge, the process cartridge can be prevented from becoming complicated and large, and the cost can be prevented from increasing, and the degree of freedom in designing the ultra-small process cartridge can be obtained.

That is, it is possible to easily and easily deal with the occurrence of an image defect due to the surface contamination of the roller without incorporating the roller cleaning means that causes the process cartridge to become complicated and large and to increase the cost.

〔Example〕

In the embodiments described below, the process cartridge frame body is provided with at least a photoconductor and a roller-shaped contact charging means (roller charging means, hereinafter referred to as a charging roller) for charging the surface of the photoconductor, and an image forming apparatus. The process cartridge is detachable from the apparatus main body, and a part of the charging roller is exposed to the outside of the process cartridge frame in order to clean the surface of the charging roller in the process cartridge.

FIG. 1 is a vertical sectional view of an electrophotographic copying apparatus as an image forming apparatus showing an embodiment of the present invention, and FIG. 2 is an external perspective view of a process cartridge.

In the figure, reference numeral 1 is a process cartridge, and a photosensitive drum 2 as an image carrier, a charging roller 3 as a roller charging means, a developing device 4, and a cleaning device 5 are built in the cartridge 1. Reference numeral 4a is a hopper for containing the developer T, and 4b is a rotating body for supplying the developer T to the photosensitive drum 2.

The process cartridge 1 is attachable / detachable to / from the image forming apparatus main body A in the lateral direction (the direction perpendicular to the paper surface in FIG. 1), and when used, it should be inserted into the apparatus main body along the pair of guide rails 6 and 6. Is positioned and held at a predetermined position by. Reference numeral 7 (FIG. 2) is a handle for attaching and detaching the cartridge 1.

In FIG. 1, reference numeral 8 denotes a document table which is made of a transparent member and reciprocates in the direction of arrow a in the figure. The document 0 is placed on the upper surface of the document table with the image surface facing downward and fixed by a document pressure plate 9. Reference numeral 10 is a lamp for illuminating the original 0, and 11 is a short-focus optical element array for exposing the reflected light from the original 0 illuminated by the lamp onto the surface of the photosensitive drum 2.

The photosensitive drum 2 rotates in the direction of an arrow b in the drawing at a predetermined peripheral speed, is uniformly charged to a predetermined polarity by the charging roller 3, and is then sequentially image-exposed by the optical element array 11 to form a drum surface. A latent image corresponding to the original image is formed on. The latent image is developed by the developing device 4 and a developed image to be transferred to the transfer material is formed on the drum surface, and is moved toward the transfer corona discharger 12 as a transfer portion by the subsequent rotation of the drum 2.

On the other hand, the transfer material P is transferred from the paper feed tray 13 to the transfer section by the transfer roller 14 and the timing roller 15, and the developed image is transferred by the transfer corona discharger 12. The transfer material P, which has finished the transfer, is separated from the drum surface by the separator 16, and then sent to the fixing device 18 via the conveying path 17 to be fixed, and is sent onto the discharge tray 20 by the discharge roller 19.
The developer remaining on the surface of the photosensitive drum is cleaned by the cleaning unit 5.
And the image forming process described above is repeatedly performed.

In the present embodiment, the charging roller 3 has a structure in which a conductive shaft 3a made of metal is coated with a conductive rubber 3b such as EPDM, and rotates while being in contact with the photosensitive drum 2. A power source is connected to the charging roller 3 through a contact (not shown) or the like, and a DC voltage or a DC voltage superposed with an AC voltage is applied to the charging roller 3 to contact the photosensitive drum 2 to give an electric charge to the drum. Is.

As described above, the charging roller 3 may hinder the uniform application of electric charges to the photosensitive drum 2 due to the scattering of the developer in the developing device 4 or the adhesion of dust or rubber from the outside. However, since such a case is rare, it is not always necessary to always install a cleaning means, and it is sufficient to clean the surface of the charging roller only when a problem occurs on the image.

So, in this example, in the process cartridge frame,
The charging roller 3 is provided with an opening 21 along the length of the roller,
The charging roller 3 is provided by exposing a part of the roller peripheral surface from the opening portion 21 to the outside of the frame body along the roller longitudinal direction, and the operation dial 22 with a knurl for rotating the charging roller 3 manually. Is provided. Production dial
An opening 24 is integrally fixed to the shaft 3a of the charging roller 3 and has a part of the peripheral surface of the dial 22 formed in the cartridge 24.
It is exposed to the outside from. Reference numeral 23 is a seal member made of a black plastic film or the like for closing the gap between the opening 21 and the charging roller 3, and is provided at the edge of the opening 21.

When an image defect or the like occurs due to the surface contamination of the charging roller 3, the process cartridge 1 is removed from the main body of the image forming apparatus, and a part of the peripheral surface of the charging roller 2 extends along the roller longitudinal direction. The opening 21 of the frame
Since it is exposed from the outside to the outside, the roller surface can be easily and surely cleaned by the cleaning member in the roller exposure opening portion 21, and the dial 22 is rotated to sequentially rotate the roller peripheral surface portion. It is possible to easily inspect and clean the entire circumference of the roller by exposing it from the opening 21 to the outside and cleaning it with a cleaning member, and it is possible to always obtain good and stable images with simple maintenance operations. Becomes

Since the manual rotation operation of the charging roller 3 is carried out by directly providing the charging roller with the dial 22 for manual rotation, and rotating the dial 22, the charging roller 3 can be easily and smoothly operated with a light torque. It is possible to quickly and efficiently clean the entire surface of the roller by manually rotating the roller.

Since the roller cleaning means is not incorporated in the process cartridge, the process cartridge can be prevented from becoming complicated and large, and the cost can be prevented from increasing, and the design flexibility of the ultra-small process cartridge can be increased.

Although the above embodiment has been described by taking the electrophotographic copying machine as an example, it can be applied to various image forming apparatuses such as a laser beam printer.

In the illustrated example, the process cartridge 1 includes the photosensitive drum 2, the charging roller 3, the developing device 4, and the cleaning device 5.
However, the present invention can be applied to a device not including one or both of the developing device 4 and the cleaning device 5, or a device provided with auxiliary exposure means or auxiliary charging means.

C. As described above, according to the present invention, in the process cartridge and the image forming apparatus in which the process cartridge is attachable / detachable, when the roller charging unit is used as the charging unit of the photoconductor, the size of the process cartridge is increased. Without this, the roller charging means provided in the cartridge can be easily cleaned. In other words, the roller cleaning means, which causes the process cartridge to become complicated and large and the cost to rise, is not incorporated, and furthermore, it is possible to easily and easily deal with the occurrence of the image defect due to the surface contamination of the roller. The advantages of the roller charging means can be fully utilized without causing the problem of dirt, and it is possible to always obtain a good and stable image, and it is possible to reduce the size and cost of the process cartridge.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of an image forming apparatus showing an embodiment of the present invention, and FIG. 2 is a perspective view of a process cartridge. 1 is a process cartridge, 2 is a photoconductor (photosensitive drum), 3 is a roller charging means (charging roller), 21 is an opening, and 22 is a dial for manually rotating the charging roller.

Claims (8)

[Claims] 1. A process cartridge attachable to and detachable from a main body of an image forming apparatus, comprising: a photoconductor, roller charging means for charging the photoconductor, and a frame body containing these. The roller charging means is provided with an opening along the length of the roller, and the roller charging means is provided by exposing a part of the roller peripheral surface from the opening to the outside of the frame along the length of the roller. A process cartridge characterized in that a roller charging means is directly provided with a dial that is manually rotated from outside the body. 2. The process cartridge according to claim 1, further comprising a developing device for developing the latent image formed on the photoconductor. 3. The process cartridge according to claim 1, further comprising a cleaning device for cleaning the photoconductor. 4. The process cartridge according to claim 1, wherein the image forming apparatus is an electrophotographic copying machine. 5. The process cartridge according to claim 1, wherein the image forming apparatus is a laser beam printer. 6. An image forming apparatus for forming an image on a recording medium, wherein a process cartridge is attachable / detachable, and a photoconductor, and roller charging means for charging the photoconductor.
A frame body containing these components, and the frame body is provided with an opening along the roller longitudinal direction of the roller charging means, and the roller charging means is provided with a part of the peripheral surface of the roller along the roller longitudinal direction. And a mounting means to which a process cartridge having a dial for manually rotating the roller charging means from the outside of the frame is directly attached to the roller charging means, is detachable, and the recording medium is conveyed. An image forming apparatus comprising: a conveying unit. 7. The image forming apparatus according to claim 6, wherein the image forming apparatus is an electrophotographic copying machine. 8. The image forming apparatus according to claim 6, wherein the image forming apparatus is a laser beam printer.