JP3320254B2 - Image forming apparatus and process cartridge thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[Object of the invention]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a process cartridge used for image formation and an image forming apparatus equipped with the same.

[0002]

2. Description of the Related Art Usually, an electrostatic latent image is formed on a photosensitive layer on a surface of an image carrier formed in a rotating cylindrical shape, and a toner image formed by applying toner to the latent image is transferred onto paper or the like. In a known image forming apparatus including a step of transferring to a material, it is necessary to sufficiently remove residual toner remaining on the surface of the image carrier every time transfer is performed.

Various means for removing residual toner have been proposed in the past, but a means for scraping and removing residual toner with a cleaning blade made of an elastic material such as rubber has a simple structure and a small size. It is well known that the toner removal function is excellent and is widely used.

FIG. 6 is a schematic side view showing an example of such an image forming apparatus, which will be briefly described below. An electrostatic latent image is formed by an image signal projected from the optical system 1 on an image carrier 7 provided in a process cartridge B detachably mounted in the image forming apparatus main body. When the transfer roller 4 arrives at the transfer site where the transfer roller 4 is disposed to face by the rotation, the transfer material 2 reaches the transfer site at this time from one of the cassettes C1 and C2 via the registration roller 3 in synchronization with the latent image. The supplied latent image on the image carrier is transferred to the transfer material.

Next, it is assumed that the transfer material is conveyed to the fixing device 5 and the toner image is fixed and fixed on the transfer material, and then discharged to the tray 6.

The process cartridge B is shown in FIG.
As shown in FIG. 2, a toner frame 12 for storing toner, a developing frame 13 having a developing sleeve 10 for supplying an appropriate amount of this toner to the image carrier 7, and a uniform surface of the image carrier 7. And a cleaning frame 14 having a cleaning section for removing and storing residual toner remaining on the image carrier.

The cleaning section of the cartridge will be described with reference to FIG. 7. FIG. 7 is a side sectional view showing only the cartridge, and a cleaning frame 14 is provided with a cleaning blade 13a which is in contact with the image carrier 7. This removes the residual toner on the image carrier. A rake sheet 13b is provided upstream of the cleaning blade 13a (as viewed in the running direction of the image carrier).
Is provided to guide the toner scraped off by the blade 13a to the toner storing portion.

In the image forming apparatus having such a configuration, when the transfer material, which has received the toner image from the image carrier at the transfer site, is subsequently conveyed to the fixing site, the cartridge, especially the cleaning frame 14 Since the transfer member proceeds downward, the curl of the transfer material, the electrostatic attraction effect, and the like, the lower surface of the frame 14 contacts the transfer material carrying the unfixed toner image, particularly, the vicinity of the rear end portion, and the toner image is disturbed. There has been a problem that the image quality is deteriorated, and the leading end enters the cleaning frame to cause a jam.

The present invention has been made in order to cope with such a situation, and a transfer material carrying an unfixed toner image and conveyed from a transfer portion to a fixing portion comes into contact with a cartridge or the like during conveyance. It is an object of the present invention to provide a process cartridge free from the above-mentioned drawbacks and an image forming apparatus using the process cartridge.

[0011]

[Object of the invention]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention relates to a process cartridge detachably mountable to an image forming apparatus, comprising at least an image carrier and a cleaning frame. A scooping sheet disposed on the cleaning frame for receiving the collected toner, wherein the scooping sheet is provided at an edge opposite to an abutting edge of the cleaning frame with the image carrier. A process cartridge (1) formed with at least one protrusion protruding from the body toward the transfer material transport path, or an image forming apparatus (2) including the process cartridge according to (1).

With such a configuration, the inconvenience of the transferred transfer material coming into contact with or intrusion of the transferred transfer material particularly into the cleaning device portion such as a process cartridge mounted in the main body of the image forming apparatus can be prevented. It can be avoided suitably.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a side sectional view of a main part showing only a process cartridge mounted on an image forming apparatus as shown in FIG. As described above, when the residual toner remaining on the image carrier 7 that does not contribute to the transfer at the transfer site (not shown) reaches the cleaning site as the image carrier 7 rotates, it is scraped off by the cleaning blade 13a. The toner is picked up by the rake sheet 13b and stored in the toner storage section on the back side.

As shown in FIG. 2, the rake sheet 13b has a projection 13b-1 having a sharp tip on the side opposite to the side in contact with the image carrier 7, as shown in FIG. It is.

With such a configuration, as shown in FIG. 6, when the transfer material separated from the image carrier after the transfer is advanced toward the fixing device 5, the rear end thereof is Even if the portion is bounced due to curl or the like, the protrusion 13b
1 can be effectively prevented from being rubbed against the bottom surface of the cartridge and causing image disturbance.

FIG. 3 shows another embodiment of the present invention, in which only the portion of the cleaning frame 14 of the cartridge b where the rake sheet 13b is disposed is shown. As shown, in this embodiment, a projection 13b-1 protruding in the direction of the transfer material conveying path is formed integrally with the cartridge body.

It will be readily understood that such a configuration provides the same operation and effect as those of the above-described embodiment. Also, since the rake sheet is usually made of a relatively flexible material such as Mylar, if the transfer material is strong, the projections may bend and the transfer material may not be prevented. By adopting the configuration as in the example, the above-described drawbacks can be avoided, and the shape of the rake sheet is simplified, which contributes to cost reduction.

The problem of the transfer material separated and advanced from the image carrier after the transfer, mainly due to the jump of the vicinity of the rear end, has been described. Next, the inconvenience caused by the jump of the front end will be described.

The leading end of the transfer material may enter the cleaning frame from between the surface of the image bearing member and the rake sheet due to curl, poor separation from the image bearing member, or the like, causing a jam. Such a situation is particularly likely to occur when printing the second side of a two-sided print.

FIG. 4 addresses such a situation. As shown, the edge of the rake sheet 13b opposite to the side in contact with the image carrier is bent in a direction approaching the image carrier. It is composed. With such a configuration, it is possible to prevent the leading end of the transfer material from entering the cleaning frame.

FIG. 5 is a perspective view showing an embodiment in which a projection 14-1 is formed at the edge of the frame in order to prevent the transfer material from entering the cleaning frame. In this case, by forming a plurality of pairs of the protrusions at positions suitable for the size of the transfer material as shown in FIG. Intrusion can be prevented. In this case, it is needless to say that a cut is made at a position corresponding to the protrusion on the fresh sheet as needed.

Although not shown, the "FIG. 1"
A protrusion 13b-1 as shown in FIG. 2 and FIG.
It is of course possible to form both the bent portion and the protruding portion as shown in FIG. 5 in one cleaning frame. Although the present invention has been described above with reference to an image forming apparatus using a process cartridge, the present invention is not limited to this, and may be applied to a normal image forming apparatus in which an image forming unit other than an image carrier is fixedly arranged in the apparatus main body. It will be readily apparent that it is applicable.

[0023]

As described above, according to the present invention, it is ensured that the image bearing surface of the transfer material separated from the image bearing member rubs against the bottom surface of the cleaning device to disturb the unfixed toner image. Can be prevented.

[Brief description of the drawings]

FIG. 1 is a side sectional view of a main part of a process cartridge according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a configuration in the vicinity of a rake sheet;

FIG. 3 is a perspective view of a configuration near a rake sheet showing another embodiment.

FIG. 4 is a side sectional view of a main part of a process cartridge showing another embodiment.

FIG. 5 is a perspective view of a configuration near a rake sheet showing another embodiment.

FIG. 6 is a schematic side sectional view of an image forming apparatus suitable for applying the present invention.

FIG. 7 is a side sectional view of the process cartridge used in the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Optical system 2 Transfer material 4 Transfer means 5 Fixing device 6 Discharge tray 7 Image carrier 12 Toner frame 13 Developing frame 14 Cleaning frame B Process cartridge

Continuation of front page (56) References JP-A-6-161173 (JP, A) JP-A-60-104961 (JP, A) JP-A-58-163971 (JP, A) JP-A-60-208782 (JP, A) , A) Japanese Utility Model Hei 2-75679 (JP, U) Japanese Utility Model Showa 63-2955 (JP, U) Japanese Utility Model Showa 62-53463 (JP, U) Japanese Utility Model Showa 63-74642 (JP, U) Japanese Utility Model Showa 61-49373 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 21/16 G03G 15/14 G03G 21/10 G03G 21/18

Claims (2)

(57) [Claims] 1. A process cartridge detachably mountable to an image forming apparatus, comprising: a process cartridge having at least an image carrier and a cleaning frame, receiving a collected toner disposed on the cleaning frame. A rake sheet is provided, and the rake sheet has at least one protrusion protruding more toward the transfer material transport path side than the cleaning frame at an edge opposite to an abutting edge between the rake sheet and the image carrier. Process cartridge formed. 2. An image forming apparatus comprising the process cartridge according to claim 1.