JPH03294874A - Image forming device - Google Patents

Abstract

PURPOSE:To prevent the exterior surface of a processing cartridge from being soiled by developer by providing a developer filter in an opening part of a cartridge container on the opposite side as an image carrier against developing device side as an image carrier against developing devices and by forming an air flow from the image carrier to a filter via the developing devices through a suction fan provided on the device main body side. CONSTITUTION:The filter 33 is provided in the cartridge container 31 of a processing cartridge 30, and the air flow is formed from the image carrier 10 to the filter 33 via the developing device 13 inside the cartridge container. Therefore, even when splattered developer is generated by developing operation of a multiple number of developing devices 13 around a photosensitive drum 10 where the developing devices 13 are installed, this developer is not stuck on the exterior surface of the processing cartridge 31 but gathered at the filter 33. Thus, the exterior surface of the processing cartridge 30 is not soiled by the developer.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an image forming apparatus such as a copying machine or a laser beam printer that employs electrophotography. The present invention relates to a forming device.

(Prior art) In addition to the photosensitive tram, which is an image carrier, a negative charger, a developing device,
2. Description of the Related Art Image forming apparatuses employing process cartridges in which process equipment such as a cleaning device is held in a cartridge container and these equipment are integrally attached to and removed from the main body of the apparatus are widely known.

When the toner in the developing device is used up, the cleaning device is full of waste toner, or the photosensitive drum or developing device itself has reached the end of its lifespan, the entire process cartridge can be replaced.
This is intended to facilitate maintenance.

On the other hand, in recent years, images have become more multicolored, and full-color images are increasingly being formed by multiple copying by arranging a plurality of developing devices with different toner colors around a photosensitive drum.

For this reason, the emergence of process cartridges having a plurality of developing devices has come to be expected.

(Problem to be solved by the invention) However, in an apparatus capable of forming full-color images, it is generally necessary to have four developing units (one for each toner color: yellow, magenta, cyan, and black) around the photosensitive drum. However, since toner and carrier scatter from these developing devices during the development process, even if these developing devices are placed inside the process cartridge, the scattered toner and carrier may stain the outer surface of the process cartridge. There was a problem that it was not easy to replace the process cartridge.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an image forming apparatus in which the outer surface of the process cartridge does not become contaminated with developer even when a plurality of developing units are housed in the process cartridge. It is on offer.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a process cartridge having at least a plurality of developing devices in addition to an image bearing member in a cartridge container, which is detachably attached to an apparatus main body. In an image forming apparatus capable of forming a color image, a developer filter is provided at the opening of the cartridge container on the side opposite to the image carrier with respect to the developing device, and a developer filter is provided at the opening of the cartridge container on the opposite side of the image carrier to the developing device. It is characterized by forming an air flow from the image carrier to the filter via the developing device.

Further, the present invention provides an image carrier in addition to the image carrier in the cartridge container.
In an image forming apparatus capable of forming a color image, in which a process cartridge having at least a plurality of developing devices is removably disposed in an apparatus main body, an electrode is disposed near the image carrier side of the developing device, and the electrode is disposed near the image carrier side of the developing device. A voltage having the same polarity as that of the developer is applied to the developer.

(Function) According to the present invention, a filter is provided in the cartridge container of the process cartridge, and an air flow is formed from the image bearing member to the filter via the developing device within the cartridge container. Even if scattered developer is generated around the installed photosensitive drum due to development operations using a plurality of developing devices, this developer is collected in the filter without adhering to the outer surface of the process cartridge. Therefore, the outer surface of the process cartridge is not contaminated with developer.

Further, according to the second aspect of the present invention, since the electrode to which a voltage of the same polarity as the developer is applied is disposed near the image bearing member of the developing device, the photosensitive drum to which the developing device is attached during the developing operation is arranged. Even if some developer is scattered around, the developer is attracted to the photosensitive drum by the action of the electrodes. Therefore, the outer surface of the process cartridge is not contaminated with developer.

(Example) Embodiments of the present invention will be described below based on the accompanying drawings.

First, a first embodiment of the present invention will be described with reference to FIG.

FIG. 1 shows a cross-sectional view of an image forming apparatus capable of forming full-color images by multiple copying. , - charger 12, yellow developer 13A, magenta developer 13B, cyan developer 13C
, and a black developing device 13D. Here, the yellow, magenta, cyan, and black developing units 13A, 13B, 13C, and 13D contain developer (toner) of each color of yellow, magenta, cyan, and black, respectively.
is movable in the direction of the arrow shown in the figure, and only a predetermined developing device 13 is moved to a developing position on the side of the photosensitive drum IO.

Further, a transfer tram 15 is provided below the photosensitive tram 10, which rotates while holding the transfer paper P by suction.

A paper feed cassette 16, a paper feed roller 17, a registration roller 18, etc. are arranged on the upstream side of the transfer tram 15 and the photosensitive tram IO, and a separation claw 19, a fixing device 20, a paper ejection roller 21, and an ejection roller are arranged on the downstream side. A paper tray 22 is also provided.

Furthermore, above the photosensitive drum 1O, etc., there is a laser diode 23, a polygon mirror 24, etc. An image light scanning unit consisting of a high speed motor 25, a lens 26, a folding mirror 27, etc. is provided, and a laser diode 23 irradiates a polygon mirror 24 rotated by the high speed motor 25 with a predetermined laser light to form an image light. , the image light is transmitted to the lens 26,
The light is exposed onto the photosensitive drum 1O via the folding mirror 27.

That is, when the photosensitive drum 10 uniformly charged by the charger 12 is exposed by the scanning unit to image light conveying information of a yellow image, an electrostatic latent image of the yellow image is formed on the photosensitive drum 10. It is formed. The electrostatic latent image is developed by the yellow developing device 13A, which is moving to the developing position of the photosensitive drum IO, and is visualized as a yellow toner image. The toner image is transferred onto the transfer paper P on the transfer tram error, and the image surface of the photosensitive drum 10 after the transfer is cleaned of residual toner by the cleaning device 11 and uniformly charged again by the primary charger 12. be done. Thereafter, magenta, cyan, and black toner images are formed on the photosensitive drum in the same manner, and these toner images are sequentially multi-transferred onto the transfer paper P onto which the yellow toner image has been transferred.

On the other hand, the transfer paper P in the paper feed cassette 16 is transferred to the paper feed roller 17.
After the sheets are taken out one by one, they are sent to the registration rollers 18, and transferred to the transfer tram 15 by the registration rollers 18.
transported upwards. The transfer paper P on the transfer drum 15 is attracted to the outer peripheral surface of the transfer tram 15 by electrical action or the like.
When a toner image is formed on the photosensitive tram lO, this transfer paper P is directed toward the photosensitive tram 10 by the rotation of the transfer tram 15, and is transferred to the photosensitive tram 1o via the bias voltage from TF, the source 28, or the transfer tram 15. As the toner image is applied toward the transfer paper P, the toner image is transferred onto the transfer paper P. After the necessary toner images of each color have been transferred, the transfer paper P is separated from the transfer tram 15 via the separation claw 19 and sent toward the fixing device 2°. And this transfer paper P
After the toner image is fixed by this fixing device 20,
t! onto the paper ejection tray 22 via the paper ejection roller 21! I#1
．． be done.

By the above operations, full-color image formation by multiple copying on the transfer paper P is completed.

Now, the photosensitive tram 1o, which is frequently replaced, the cleaning device 11, the charger 12, yellow, magenta, cyan,
Fluff developing devices 13A and 13B.

For process equipment such as 13C113D, cartridge container 3
1, and is disposed as a process cartridge 30 in the apparatus main body 1 so that it can be easily attached and detached. In the process cartridge 3o, the toner in the developing device 13 is used up, the cleaning device 11 is full of waste toner, or the life of the photosensitive drum 10 or the developing device 13 has reached the end.

This is intended to facilitate maintenance by replacing the entire flosser cartridge holder 30.

Here, above yellow, magenta, cyan, flash')
Ilfj'X l 3 A, 13 B, 13C11
When forming a full-color image using 3D, if the developing device 14 itself or the outer surface of the cartridge container 31 of the process cartridge 30 becomes dirty with toner or carrier scattered during the developing operation of the developing device 13, the process cartridge It becomes difficult to attach and detach the 3o.

Therefore, in this embodiment, the internal process equipment is housed in the cartridge container 31 so as to be wrapped therein, and an opening 32 is provided in the cartridge container 31 on the side opposite to the photosensitive tram 1o with respect to the developing device 13. A filter 33 for developer such as toner was attached to 'tl132. Further, a suction fan 34 is attached near the outer wall of the apparatus main body 1, and the suction fan 34 and the filter 33 are connected through a duct 35.

By using the yellow, magenta, cyan, and black developing devices 13A, 13B, 13C, and 13D to form full-color images, it is possible to prevent toner and carrier of each color from scattering around the photosensitive drum 10. Even if the duct 32 and filter 3 are
3, the air inside the process cartridge 30 is suctioned, and within the process cartridge 30, an air flow F flows from the photosensitive drum 10 to the filter 33 via the developing device 13.
As a result, the scattered toner and the like are sucked into the cartridge container 31 and are all absorbed by the filter 33.

Therefore, since toner and the like are not scattered outside the process cartridge 30, the process cartridge 30
The process cartridge 30 is not contaminated with toner, etc., and the process cartridge 30 can be easily attached and detached.

Note that the suction fan 34 is located outside the main body 1 of the apparatus near the filter 33. It is most preferable if it is placed near the 4th wall,
The filter 33 may be placed anywhere on the device body 1 as long as it is near the outer wall of the device body 1.
A sufficient duct 32 is required between the duct and the suction fan 34.

Furthermore, if a sealing lid 36 is disposed between the upper surface of the yellow developing device 13A, which is the uppermost one of the developing devices 13, and the inner surface of the cartridge container 31, toner, etc. around the filter 33 may be removed due to vibrations when the process cartridge 30 is attached or detached. It does not scatter to the outside from the image exposure window 37 or the like.

Next, a second embodiment of the present invention will be described with reference to FIGS. 2 and 3. Components having the same functions as those in the first embodiment are designated by the same reference numerals, and their explanations will be omitted.

In this embodiment, four developing devices 13A and 1 according to the first embodiment are used.
Among 3B, 13c, and 13D, only the black developing device 130, which uses a particularly large amount of toner, is used as the process cartridge 30.
A case will be described in which the black developing device 13D is separately attached to and detached from the apparatus main body 1.

In this case, as shown in FIG.
It is also possible to make the upper surface of D also serve as a part of the bottom wall 31a of the cartridge container 31, but in this case, the air flow F flowing from the photosensitive tram 1O to the filter 33 via the developing device 13 Since it passes between the cyan developing device 13C and the black developing device 13D, the outer surface of the black developing device 13D becomes dirty with toner T, etc., making it difficult to attach and detach the black developing device 13D from the apparatus main body l. In addition, in this case, when installing and removing the process cartridge 30, the bottom surface of the cyan developer 13C dirty with toner is exposed.
It also becomes difficult to attach and detach the process cartridge 30.

Therefore, as shown in FIG. 2, the bottom wall 31a of the cartridge container 31 of the process cartridge 30 is extended to the vicinity of the outer surface of the photosensitive drum 10, and a span plate is attached to the outer wall end of the black developing unit 13D near the photosensitive drum 10. 40
was attached so that the spanning plate 40 was brought into contact with the end of the bottom wall 31a of the cartridge container 31.

Therefore, even if an air flow F is generated in the process cartridge 30 from the photosensitive drum 10 via the developing device 13 to the filter 33, this air flow F is not connected to the black developing device 1.
Since there is no leakage to 3D, black developer 13
Since the black printer 13D and the process cartridge 30 are not contaminated with toner, and the outer surface of the process cartridge 30 itself is not contaminated with toner, it is easy to attach and detach the black printer 13D and the process cartridge 30 from the main body 1. In addition, since there is a spanning plate 40, toner etc. scattered from the vicinity of the black developing device 13D around the photosensitive drum 10 is also moved toward the filter 33 by the air iF in the process cartridge 30, so that the toner in the black developing device 13D Contamination caused by such things is further reduced.

Next, a third embodiment of the present invention will be described with reference to FIG. In addition, 1st. Components having the same functions as those according to the second embodiment are given the same reference numerals and their explanations will be omitted.

In this embodiment, an electrode 4 is provided around the photosensitive tram 10 of the developing device 13.
1 is disposed, and the electrode 41 electrically prevents scattered toner and the like from adhering to the outer surface of the process cartridge 30 and the like.

For example, an electrode 41 is provided on the photosensitive drum 10 side of the span plate 40 provided between the end of the bottom wall 31a of the process cartridge 30 of the second embodiment and the outer wall end of the black developing device 13D, and the electrode 41 is provided with the toner. Apply a voltage with the same polarity as the carrier. In this way, even if toner or the like is once scattered around the photosensitive drum 10 during the developing operation, the scattered toner or the like will adhere to the photosensitive drum IO due to the influence of the electrode 41 and will not be scattered to the outside. Therefore, the outer surfaces of the process cartridge 30 and the black developing device 13D are not contaminated by scattered toner and the like, and the same effects as in the first and second embodiments can be obtained. Note that since the amount of scattered toner is small, even if it adheres to the photosensitive drum 10, it will not disturb the image on the photosensitive drum 10.

The magnitude of the voltage applied to the electrode 41 is
It depends on the distance between the photosensitive tram 10 and the distance 11.
The value of IKV is reasonable from the number +V per 1 mm, and in the case of this example (the distance is 2-1 and the toner is negatively charged) -6
Good results were obtained by applying a voltage of 00V.

Note that the above electrode 41 is connected to the photosensitive drum 10 between each developing device 13.
If the process cartridge 30 is located close to the
The filter 33 and the suction fan 34 on the device main body l side become unnecessary.

(Effects of the Invention) As is clear from the above description, according to the present invention, even if scattered developer is generated around the photosensitive drum due to development work using a plurality of developing devices, the developer passes through the process cartridge and filters. The outer surface of the process cartridge is not contaminated by this developer, and therefore, the process cartridge can be easily attached to and removed from the main body of the apparatus.

Further, according to the present invention, an electrode is disposed near the image bearing member of the developing device, and the scattered developer generated during the developing operation is electrically attracted to the photosensitive drum by the electrode, so that the process cartridge The outer surface is not contaminated by this developer, and the process cartridge can be easily attached to and detached from the apparatus main body.

[Brief explanation of drawings]

FIG. 1 is a side sectional view of an image forming apparatus according to a first embodiment, FIG. 2 is an explanatory diagram of the lower part of the process cartridge of an image forming apparatus according to a second or third embodiment, and FIG. 3 is a side sectional view of an image forming apparatus according to a second embodiment. FIG. 3 is an explanatory diagram of the lower part of the process cartridge for explaining an example. l...Device main body, 10...Image carrier (photosensitive drum)
, 13, 13A, 13B, 13C, 13D--Developer, 30, process cartridge, 31, cartridge container, 32, opening, 33, filter, 41, electrode, F -Airflow. Figure 2 Figure 3

Claims (3)

[Claims] (1) In an image forming apparatus capable of forming a color image, in which a process cartridge having at least a plurality of developing devices in addition to an image carrier in a cartridge container is removably attached to the main body of the apparatus, A developer filter is provided at the opening of the cartridge container on the opposite side of the image carrier, and an air flow is created from the image carrier, via the developer, and to the filter via a suction fan provided on the main body of the device. An image forming apparatus characterized by: (2) In an image forming apparatus capable of forming a color image, in which a process cartridge having at least a plurality of developing devices in addition to an image carrier in a cartridge container is removably installed in the apparatus main body, the developing device An image forming apparatus characterized in that an electrode is disposed near the image carrier side, and a voltage of the same polarity as that of the developer is applied to the electrode. (3) The image forming apparatus according to claim 1 or 2, wherein at least one of the developing devices is independently attached to and removed from the apparatus main body separately from the process cartridge.