JP2003280324A - Color image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the usability and to miniaturize an image forming apparatus. <P>SOLUTION: In a process cartridge, a Bk developing device, an electrifying means, a photoreceptor drum and a cleaning means are integrated. Color developing devices are loaded on a rotary. Furthermore, the rotary and the color developing devices are also integrated into a process cartridge. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plurality of process cartridges used for image formation of an electrophotographic recording system such as a laser printer, a copying machine and a facsimile, and an image forming apparatus for mounting these process cartridges to form a color image. is there.

[0002]

2. Description of the Related Art Various color image forming apparatuses for forming a color image on a transfer material by utilizing an electrophotographic recording system have been devised, and some of them have been put into practical use.

As a typical example thereof, a developing device containing toner, which is a developer of each color, is provided for a photosensitive member, which is an electrostatic latent image bearing member, so as to be sequentially developed. For example, yellow, magenta, and A rotary developing device equipped with a developing device for four colors of cyan and black visualizes the electrostatic latent image of each color formed on a common photoconductor as a toner image at the developing position by each developing device. There is a so-called rotary type image forming apparatus that forms a multicolor toner image by repeating the step of transferring onto a sheet-shaped recording medium (transfer material) such as paper each time an image is obtained.

Further, a plurality of photoconductors are used to separately form toner images of respective colors by developing devices of respective colors, and the transfer materials are conveyed while transferring the multicolor toners from the respective photoconductors in sequence. There is an in-line type image forming apparatus that forms an image.

Here, a type in which a multicolor toner image is formed by sequentially superposing toner images of respective colors on an intermediate transfer member (transfer material), not directly on the recording medium, and then collectively transferred to the recording medium There is also.

Each of the typical methods of the color image forming apparatus using the electrophotographic recording method has advantages and disadvantages. In particular, the rotary method described above forms a color image using one photoconductor. Therefore, it is advantageous from the viewpoint of color registration adjustment, product miniaturization and cost reduction, and there are some products that have been put to practical use by this method.

FIG. 4 is a block diagram for explaining a conventional image forming apparatus adopting the rotary system, and an outline of image formation will be described below.

An image forming apparatus such as a color laser printer as shown in FIG. 4 is connected to a host such as a personal computer or a workstation (not shown), and a video interface is used in response to a print request from the host. Receive image data. 4 of yellow Y, cyan C, magenta M, and black K based on this image data
Toner images of respective colors are sequentially formed from the image data separated into colors, and the toner images are superposed on the intermediate transfer member and collectively transferred to a transfer material such as paper to obtain a full-color image.

In FIG. 4, reference numeral 40 denotes a photosensitive drum as an electrostatic image carrier, which is rotationally driven in the direction of arrow A at a predetermined peripheral speed. First, the surface of the photoconductor is uniformly charged by applying a predetermined bias to the core of the charging roller 41 as a charging means. Next, the exposure means 5 whose ON / OFF is controlled according to the image data of the first color
By 0, scanning exposure is performed at a predetermined resolution to form a first electrostatic latent image.

The electrostatic latent image formed in this manner is developed and visualized by a developing device 43 which can be attached to and removed from the rotary 42. The developing device 43 contains, for example, Y toner as the first color toner. The first developing device 33a, the second developing device 43b containing M toner as the second color toner, the third developing device 43c containing C toner as the third color toner, and the fourth color developing device 43c. K as toner
The fourth developing device 43d contains toner, and is located at the position facing the photosensitive drum (arrow B when forming an image of each color).
The sleeve carrying the toner regulated to a prescribed layer thickness by a toner layer regulation means (not shown) is rotationally driven, and a prescribed bias is applied to the core metal of the sleeve. To develop.

First, the first electrostatic latent image is developed and visualized by the first developing device 43a, and the visualized toner image of the first color is an intermediate transfer member 44 as a second image carrier. A predetermined transfer bias is applied at the first transfer portion 45a, which is a nip portion between the and, to electrostatically transfer (primarily transfer) the surface of the intermediate transfer member 44. 1
The toner remaining on the surface of the photosensitive drum 40 after the next transfer is removed by the cleaning device 46 to prepare for the next latent image formation.

Subsequently, the same steps are repeated, each time the toner image of the second color developed by the M toner, C,
A third color toner image developed with toner and a fourth color toner image developed with K toner are sequentially transferred and laminated on the surface of the intermediate transfer member 44 to form a color toner image.

Thereafter, the transfer belt 47, which is in a state of being separated from the surface of the intermediate transfer member 44, is pressed against the surface of the intermediate transfer member 44 with a predetermined pressing force, is driven and rotated, and a predetermined transfer bias is applied. Second transcription site 45b
At this time, the color toner images laminated on the surface of the intermediate transfer member 44 are collectively transferred (secondary transfer) to the surface of the transfer material P conveyed at a predetermined timing, and the transfer material P is transferred to the fixing device 48. After being conveyed and fixed as a permanent image, it is discharged out of the apparatus to obtain a desired color print image.

The intermediate transfer member 44 after the secondary transfer is completed.
The toner remaining on the surface is removed at a predetermined timing by the intermediate transfer member cleaning device 49 that comes into contact with the surface of the intermediate transfer member 44, and is prepared for the next image forming step.

In a recent laser printer, it is not necessary for a user to replace consumable parts such as a photoconductor and a developer which are difficult for a user to replace, and it is not necessary to perform maintenance such as processing of waste toner. Many adopt a different process cartridge system.

In the above example, the developing means 43 for Y, M, C and K in which the container containing the toner and the developing means are integrated.
Each of a, 43b, 43c, and 43d is one developing cartridge. Normally, it has a means to detect the remaining amount of toner, and when the toner of a cartridge of a certain color runs out and the life is reached, the user can simply replace the cartridge and continue to use it. There is.

Further, there has been proposed a drum cartridge in which the photoconductor 40, the charging means 41 and the cleaning means 46 are integrated. Normally, in this drum cartridge, when the surface layer of the photoconductor is scraped by a predetermined amount due to repeated image forming operations, when the photoconductor exceeds a predetermined rotation speed, or the cleaner of the cleaning means is full of transfer residual toner. When it reaches the end of its life,
The user can replace the cartridge and continue to use it.

The life of these process cartridges is notified by detecting the degree of wear of each of them, and the user can replace them separately. In addition, because it is designed to optimize for each life, it is possible to always obtain a good image with no defects until the life of the cartridge, and at the end of the life of the cartridge. There is an advantage that the user can easily perform the exchange.

[0019]

However, in the conventional image forming apparatus adopting the rotary system as shown in FIG. 4, when the user replaces the developing cartridge of a certain color which has reached the end of life, the operation button is pressed. After replacing the cartridge by pushing the cartridge etc. to the take-out position, the replacement work will be performed. Further, in a device of a type in which each color cartridge is sequentially rotated to the take-out position by pressing the operation button, there is a problem that the cartridge of the replaced color cannot be taken out unless the operation button is pressed four times at worst.

If the developing cartridge for each color is inserted by mistake, it is difficult to detect this. Even if the image forming apparatus detects an erroneous insertion by some means (such as storing color information in a memory in advance),
It is difficult for the user to replace it. Although it may be considered that the shapes and the like are mechanically incompatible, there arises a problem that the user breaks the main body by forcibly inserting it.

Further, in the monochrome image forming apparatus for the purpose of cost reduction, there is a developing cartridge in the market which does not detect the remaining toner amount as described above, and the user finds that the image is blank. The life is judged by and the cartridge is replaced. In the color image forming apparatus as shown in FIG. 4, in the case where the developing cartridge is configured so that the detection of the remaining toner amount is omitted, even if the user can confirm the white spot of the color image, the development of any color can be performed. There is also a problem that it is difficult to determine whether to replace the cartridge.

On the contrary, in order to inform the user of which color of the developing cartridge should be replaced, at least the above-mentioned life detecting means for detecting the remaining amount of toner and the liquid crystal for notifying which color has reached the end of life. It is necessary to provide a display means including the above, and the cost will be increased accordingly.

On the other hand, black (Bk) which is generally used frequently
If the capacity of the developing device containing the toner is to be made larger than that of the toner of the other color, it is necessary to increase the outer diameter of the rotary, and there is also a problem that the entire apparatus becomes large. The present invention is to solve the above problems,
It is intended to improve maintenance workability in a color image forming apparatus, prevent erroneous insertion of a developing device, and improve usability.

In addition to increasing the capacity of the developing device containing black (Bk) toner, which is frequently used, to reduce the frequency of exchanging consumables and to reduce the running cost especially for monochrome printing, It is intended to achieve downsizing of an image forming apparatus.

[0025]

In order to achieve the above object, according to the first invention of the present application, a rotatable image carrier, a charging means for charging the image carrier, and the image carrier after charging. A latent image forming means for forming an electrostatic latent image on the body, a plurality of developing means for visualizing the electrostatic latent image on the image carrier, and the visualized developer image are transferred to a transfer material. In a color image forming apparatus having a transfer means and a cleaning means for removing a developer remaining on the image carrier after the transfer, at least one developing means among the plurality of developing means is fixedly arranged, and the fixedly arranged developing means. Means, the image carrier, the charging means,
The cleaning means is a process cartridge detachably mountable to the color image forming apparatus, and the other developing means are mounted on a rotatable developing means holder.

According to a second invention of the present application, in the first invention, the rotatable developing means holder and the developing means mounted on the developing means holder are integrated to provide the color image forming apparatus. It is a detachable process cartridge.

A third invention according to the present application is characterized in that, in the first and second inventions, at least the developer carrier of the fixedly arranged developing means is not in contact with the image carrier. .

A fourth invention according to the present application is characterized in that, in the first to third inventions, the developing means fixedly arranged is a developing means containing a black developer.

A fifth invention according to the present application is characterized in that, in the first to fourth inventions, the developer contained in the fixedly arranged developing means is a magnetic one-component developer.

According to a sixth invention of the present application, in the first to fifth inventions, the cleaning means stores a cleaning member for removing the developer remaining on the image carrier and the removed developer. And a storage member for storing the storage member.

In the seventh invention according to the present application, the material to be transferred is an intermediate transfer member for transferring the developer images of respective colors to the transfer material in a batch after sequentially performing multiple transfer.

By adopting the above-mentioned structure, there are the following effects.

According to the first aspect of the invention, since the image carrier, the developing means, the charging means, and the cleaning means are process cartridges, maintenance work such as replacement of the developing means and replacement of the image carrier which has reached the end of its life are carried out. The user's work related to is reduced, and stable output images can be obtained by a simple operation.

According to the second aspect of the invention, it is not necessary to attach and detach the developing means rotation holder and the developing means which occur when the developing means built in the developing means rotation holder is replaced.
Eliminates damage to the image forming device due to incorrect insertion of developing means,
The user can easily replace the developing means.

According to the third aspect of the invention, since the developing means fixedly arranged is not in contact with the image carrier, the developer contained in the developing means incorporated in the rotary holder for the developing means is fixedly arranged. It is possible to prevent color mixture of the developer contained in the developing means, and obtain a good image.

According to the fourth aspect of the invention, the developing means which normally contains the black developer, which is the most frequently used color, can have a large capacity of the developer and the number of times of replacement can be reduced. And the running cost of the device can be reduced.

According to the fifth aspect of the invention, since the magnetic one-component developer is used, the developer carrier can hold the developer by the magnetic force, so that the developer falls from the developer carrier (hereinafter It is possible to provide a color image forming apparatus which is excellent in environmental stability and durability stability.

According to the sixth aspect of the present invention, the user can simultaneously treat the developer removed from the image bearing member during the life of the developing means or the image bearing member, thus reducing the labor of the user. It is possible to reduce.

According to the seventh aspect of the invention, by using the intermediate transfer member as the transferred material, the influence of the paper dust of the recording paper on the image bearing member can be achieved without the recording paper and the image bearing member contacting each other. It is possible to obtain a stable image over a long period of time.

[0040]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [First Embodiment] FIG. 1 shows a schematic structure of a color image forming apparatus embodying the present invention.

FIG. 1 is a sectional view of a color laser printer which is one form of a color image forming apparatus. The color laser printer includes a photosensitive drum 1 as an image carrier that rotates at a constant speed, and a charging roller as a charging means. 2. A cleaning device 6 and a black developing device 5 for removing waste toner adhering to the surface of the photosensitive drum 1 in the process of image formation described later.
B is integrated with the photosensitive drum cartridge 7, three color developing device cartridges 3 (yellow developing device 3Y, which are housed in the rotary 4 as a rotatable developing device holder)
An image forming unit including a magenta developing device 3M and a cyan developing device 3C), an exposure unit 8, an intermediate transfer member 9, a primary transfer roller 10, a secondary transfer roller 11, a conveyance guide 12, and a fixing device 13 are main components. It

The color developing devices 3Y, 3M, 3C housed in the rotary 4 and the photosensitive drum cartridge 7 are detachably attached to the main body of the image forming apparatus. The surface of the photosensitive drum 1 as an image carrier uniformly charged by the charging roller 2 is irradiated with a laser beam modulated according to image data from a host such as a personal computer from the exposure means 8 and desired for each color. An electrostatic latent image of is obtained. The electrostatic latent image is reversely developed at the developing portion by developing devices 2B, 4Y, 4M, and 4C, which are disposed opposite to the electrostatic latent image, and are developing means containing toner of each color, and are visualized as a toner image. . During the image forming operation, the black developing device 3B integrated with the photosensitive drum 1 is always arranged to face the photosensitive drum 1 at the developing position 2a. On the other hand, the color developing device housed in the rotary 4 is controlled so as to sequentially face the photosensitive drum 1 at the developing position 4a as the rotary 4 rotates.

The toner images of the respective colors sequentially visualized as described above are applied to the intermediate transfer member 9 which is rotationally driven at the first transfer portion T1 by a voltage (primary transfer) having a polarity opposite to the charging polarity of the toner. (Bias) is applied to the primary transfer roller 10 to electrostatically transfer (primary transfer) to the surface of the intermediate transfer body 9.
To be done. The intermediate transfer member 9 has a peripheral length slightly longer than the length of the transfer material, and while being pressed against the photosensitive drum 1 with a predetermined pressing force, a peripheral speed substantially equal to the peripheral speed of the photosensitive drum 1. Thus, the photosensitive drum 1 is rotationally driven in the forward direction with respect to the rotational direction.

A small amount of waste toner remaining on the surface of the photosensitive drum 1 after the primary transfer is removed by the cleaning device 6. On the other hand, the toner image of each color is transferred and laminated on the surface of the intermediate transfer member 9 by repeating the above process three times.

Next, the secondary transfer roller 11, which is in a state of being separated from the surface of the intermediate transfer body 9, is rotationally driven while being pressed against the surface of the intermediate transfer body 9 with a predetermined pressing force. A voltage (secondary transfer bias) having a polarity opposite to the charging polarity of the toner is applied to the secondary transfer roller 11 from a high voltage power source (not shown), so that the toner image formed on the surface of the intermediate transfer body 9 is formed. , Is collectively transferred (secondary transfer) onto the surface of the transfer material P that is conveyed to the second transfer portion T2 at a predetermined timing. The transfer material P is conveyed to the fixing device 13, fixed as a permanent image, and then ejected to the outside of the apparatus.

The toner remaining on the surface of the intermediate transfer body 9 after the secondary transfer is completed is brought into contact with or separated from the surface of the intermediate transfer body 9 at a predetermined timing by an intermediate transfer body cleaning device (not shown). To be removed. Next, the photosensitive drum cartridge 7 used in this embodiment will be specifically described. The photosensitive drum is a negative polarity OPC photosensitive member having a diameter of 50 mm. Further, the charging roller 2 is formed by forming a rubber layer such as EPDM, urethane, NBR, or epichlorohydrin rubber in a single layer or a plurality of layers on a conductive base shaft such as a nickel-plated steel rod, and the rubber layer is a photosensitive drum. It is preferable to provide a protective layer in order to prevent contamination of the. A material such as water-soluble nylon can be used for the protective layer. In this example,
Foamed EPDM with a thickness of 2.5 mm is formed on a φ6 mm nickel-plated steel rod, and a NB with a thickness of 500 μm is formed on it.
An AC bias and a DC bias were superposed on the charging roller 2 using R and a fluorine resin as a protective layer by a high voltage power source (not shown). Further, the cleaning device 6 includes a cleaning blade 6a and a waste toner storage portion 6b.

In this embodiment, the charging roller 2 is used as the charging means, but the charging means is not particularly limited, and it is possible to use other charging methods such as a fur brush and a corona charger. In addition, the cleaning device 6
Uses a cleaning blade, but it is also possible to use other cleaning means such as a brush roller.

Further, the bias applied to the charging means is not particularly limited and may be only DC bias.
Next, the black developing device cartridge 5B is a reversal developing device using a non-magnetic one-component toner (negative toner) as a developer (hereinafter, the developer is referred to as toner). The black developing device cartridge 5B supplies the non-magnetic toner to the developing roller 5a which contacts the photosensitive drum 1 and rotates while rotating in the direction of the arrow in FIG. A supply roller 5b as a toner supply means, a developing blade 5c as a toner regulating means for regulating the toner application amount and a charging amount on the developing roller 5a, a toner is supplied to the supply roller 5b, and a non-magnetic one-component toner is agitated. The stirring member 5d and the like.

In the present embodiment, the developing roller 5a preferably has elasticity because the developing is carried out by contacting the photosensitive drum 1 which is a rigid body. Although silicone rubber was used as the elastic layer, as the rubber used for the elastic layer, other NBR rubber (NBR: nitrile rubber), butyl rubber, natural rubber, acrylic rubber, hydrin rubber, urethane rubber, etc. are generally used. Rubber can be used. Usually, by increasing the oil impregnation amount of the rubber material, the hardness can be reduced. When the developing roller 5a has a single layer, urethane rubber, silicone rubber, NBR rubber, etc. are preferably used from the viewpoint of chargeability to the toner when negatively chargeable toner is used. If a positively chargeable toner is used, fluororubber or the like is preferably used.

Further, when a coat layer is provided on the outer periphery of the elastic layer in consideration of charging of the toner, polyamide resin, urethane resin, silicone resin, acrylic resin, fluororesin, or a mixture thereof is preferably used. Used. The developing blade 5c is the developing roller 5a.
It is possible to use a known toner regulating member whose contact portion with is made of metal or rubber and a resin member. In this embodiment, about 2 m from the tip of the stainless steel thin plate (about 0.1 mmt)
The one in which the position of m was bent in the direction opposite to the developing roller, and the bent portion was in contact with the developing roller 5a in a state of slightly biting in, was used.

The toner agitated by the agitating member 5d is supplied onto the developing roller 5a by sliding friction between the rotating developing roller 5a and the supplying roller 5b rotating in the direction of the arrow. The toner on the developing roller 5a is provided with a desired charge amount by the developing blade 5c, the toner amount is regulated, and the toner is appropriately carried on the developing roller 5a. When the toner carried on the developing roller 5c reaches a portion in contact with the photosensitive drum 1, that is, a developing portion a, a developing bias is applied to the developing roller 5a from a power source (not shown), so that the peripheral surface of the photosensitive drum 1 is covered. The electrostatic latent image carried by the toner is reverse-developed with the toner carried on the surface of the developing roller 5a to be visualized as a toner image.

Since the color developing device cartridge 3 has the same structure as the black developing device 5B, its explanation is omitted.
Further, the color developing device cartridge 3, the black developing device 5
In B, a 4k image (A4, 4% printing) printable toner was filled. At this time, the rotary 4 which holds the color developing device cartridge 3 has an outer diameter of 130 mm. In this embodiment, the contact developing method is used for all developing means, but the developing method is not particularly limited,
Alternatively, a jumping developing method, a two-component developing method, or the like can be used. In addition, each cartridge has
Each of them is provided with a means for detecting the life as described below.

Photosensitive drum cartridge 7 ... Black toner remaining amount detecting means, drum life detecting means, waste toner full amount detecting means Color developing device cartridge 3 ... Color toner remaining amount detecting means The life detection information emitted from the life detection means is transmitted to a control unit (not shown) of the image forming apparatus body, and the control unit displays a cartridge (not shown) to the user which cartridge needs to be replaced. Control to display on. That is, the photosensitive drum cartridge 7 includes the black developing device 5B, the photosensitive drum 1, and the cleaning device 6.
Is integrally formed, when any one of the black toner remaining amount detecting unit, the drum life detecting unit, and the waste toner full amount detecting unit is detected, a display prompting the user to replace is displayed. Further, the color developing device cartridge 3 displays a message prompting the user to replace the developing device cartridge of the color detected by the toner remaining amount detecting means.

The display means includes, for example, a liquid crystal panel for displaying the name of the cartridge which has come to be replaced, and an LE which is assigned in advance to each cartridge.
It can be simplified by using a means such as indicating the cartridge to be replaced by lighting D. Therefore, as described above, the user can appropriately replace the consumable item of the image forming apparatus by replacing the cartridge shown in the display unit of the image forming apparatus, and always obtain a stable and high-quality image. It has become possible.

As described above, in the color image forming apparatus of the present embodiment, when the photosensitive drum 1 which is a consumable item is replaced or the toner of each color is replenished, the photosensitive drum cartridge 7 or the three types of color developing devices 3 ( (Yellow, magenta, cyan) will be replaced as needed. (There are four types of cartridges that need to be replaced.) Therefore, in addition to the cartridge containing at least the photosensitive drum 1, an image forming apparatus having a configuration in which four color developing devices of black, yellow, magenta, and cyan are used as respective cartridges. It is possible to more easily replace the cartridge, which tends to be complicated, as compared with the above.

[Second Embodiment] The second embodiment will be described below. The color image forming apparatus and the image forming operation applied in this embodiment are the same as those in the first embodiment, and thus the description thereof is omitted.

In this embodiment, the developing means containing the black toner is a photosensitive drum cartridge provided with a charging means, a cleaning means and a photosensitive drum, and the rotary and the developing means mounted on the rotary are integrally formed. The process cartridge is detachable from the color image forming apparatus.

A detailed description will be given below with reference to FIG. The color process cartridge 20 shown in FIG. 2 is composed of a color developing device containing magenta, cyan, and yellow toners, and is integrally formed with the rotary 21. Further, the shutter 26 of the color cartridge is fixed to the outer peripheral surface of the rotary 21, has an opening only at a position facing the photosensitive drum 1, and the developing roller 22 comes into contact with the photosensitive drum 1 at the opening A, so that the color cartridge 20 When putting on and taking off
At the position where the developing roller 22 is not exposed at the opening, the rotary 2
Stop 1 Further, the color cartridge 20 has a structure in which a gear (not shown) is provided at the end of the rotary 21, the drive is transmitted from the color image forming apparatus, the rotary 21 is rotated, and colors are switched at the time of image formation.

Here, the black developing device mounted on the photosensitive drum cartridge has the same configuration as that of the first embodiment, and the toner filling amount is set to a printable amount of 5k image (when printing A4 4%). Each developing device of the color process cartridge is filled with a toner amount capable of printing a 1k image (when printing A4 4%) in order to further reduce the outer diameter of the rotary 21. At this time, the rotary 4 holding the color developing device cartridge has an outer diameter of φ10.
It is 0 mm.

Further, the color image forming apparatus according to the present embodiment is configured without the toner remaining amount detecting means, the drum life detecting means, and the waste toner full amount detecting means. The toner remaining amount detecting means is omitted because the user can determine whether there is toner or not due to blank toner. this is,
Since the color developing device cartridge is integrated for each color,
This is because the user only needs to identify black or other colors when there is no toner, such as white spots, and it is not necessary to distinguish between magenta, cyan, and yellow, so that it is possible to easily determine that there is no toner.

Further, since the drum life detecting means makes the drum life sufficiently long with respect to the capacity of the toner cartridge, it can be omitted because the toner is exhausted first. Specifically, in the present embodiment, the drum life is 15
It is set as k image. Further, the waste toner full amount detecting means is set so that the amount of waste toner stored in the waste toner container 6b is not filled earlier than the life of the photosensitive drum. Therefore, since the toner is exhausted first and the cartridge is replaced, it can be omitted.

As described above, in the color image forming apparatus according to this embodiment, when the photosensitive drum 1 which is a consumable item is replaced or the toner of each color is replenished, the photosensitive drum cartridge 7 or one type of color developing device cartridge is used. 21
(Yellow, magenta, cyan) will be replaced as needed. (There are two types of cartridges that need to be replaced.) Therefore, in addition to the cartridge including at least the photosensitive drum 1, an image forming apparatus in which four color developing devices of black, yellow, magenta, and cyan are used as respective cartridges Compared with, it was possible to more easily replace the cartridge, which tends to be complicated. Further, since it is not necessary to attach / detach the rotary and the color developing device cartridge, which occurs when the color developing device cartridge is replaced,
Erroneous insertion of the color developing device for each color is eliminated, and the user can easily replace the developing means.

Further, in the color image forming apparatus according to the present embodiment, since the black developing device 2B is not mounted on the rotary 4, the amount of black toner filled in the black developing device 3B is increased so that the black developing device 3B is Even if the size is increased, the outer diameter of the rotary 4 can be suppressed to be small, and the image forming apparatus can be downsized. Further, since the life of the black developing device 3B can be easily extended, the number of times of exchanging the black developing device 3B, which is frequently used, can be reduced, and the labor of the user for the replacement work can be reduced. .

Further, since the remaining toner amount detecting means, the drum life detecting means, and the waste toner full amount detecting means are not provided, the various detecting means are not provided, so that it is not necessary to provide the display means and the like, and the cost increase is suppressed. It became possible to do.

[Third Embodiment] The third embodiment will be described below. The color image forming apparatus and the image forming operation applied in this embodiment are the same as those in the first embodiment, and thus the description thereof is omitted. In the present embodiment, the developing means containing the black toner is a photosensitive drum cartridge including a charging means, a cleaning means, and a photosensitive drum. The rotary and the developing means mounted on the rotary are integrally formed, and The process cartridge is detachable from the image forming apparatus, and the developing means contained in the photosensitive drum cartridge is a non-contact developing means.

A concrete description will be given with reference to FIG. The photosensitive drum cartridge 7 includes a black developing device 30, a charging unit 2, a photosensitive drum 1, and a cleaning device 6,
Since the charging unit 2, the photosensitive drum 1, and the cleaning device 6 are the same as those in the first and second embodiments, their description will be omitted. The black developing device 30 includes a non-magnetic developing sleeve 30a as a developer carrying member formed of an aluminum or stainless steel pipe and a magnet 3 arranged in the developing sleeve.
0b, an agitating member 30d, 30e which is mainly composed of an elastic blade 30c formed of, for example, urethane rubber or silicone rubber, which is attached to a sheet metal as a toner regulating member, and assists in sending the toner to the vicinity of the developing sleeve 30a. have.

Further, in this embodiment, the black developing device 3
No. 0 contains a one-component magnetic toner, and the developing step is performed by a well-known jumping developing method which is a non-contact developing method. Specifically, in the non-magnetic developing sleeve 30a, the photosensitive drums 1 are arranged to face each other in a close state, and the toner attached to the developing sleeve 30a in a thin layer is supplied from an AC bias power source (not shown) to the developing sleeve. A predetermined AC bias voltage (not shown) of, for example, several KHz applied to 30a.
(Usually, a voltage obtained by superimposing a DC voltage on an AC voltage) flies from the developing sleeve 30a and adheres to the photosensitive drum 1 to develop the electrostatic latent image formed thereon.

Since the black developing device 30 contained in the photosensitive drum cartridge 7 uses a jumping developing method which is a non-contact developing method with the photosensitive drum 1, black developing is performed during the developing operation in the color developing device cartridge 20. Bowl 3
Color mixture due to transfer of toner from 0 to the photosensitive drum 1 can be prevented. Further, since the magnetic toner is used, it is held by the magnetic force of the magnet 30b in the developing sleeve 30a. Therefore, even if the amount of charge held by the toner changes due to the environment and long-term use, the toner will be retained in the developing sleeve 30.
It is possible to prevent image defects due to stains in the color image forming apparatus and the intermediate transfer member 9 without causing fluffing from a.

The color developing device cartridge 20 has the same structure as that of the second embodiment, and the toner filling amount of each cartridge is the same as that of the second embodiment. Also in this embodiment, the toner remaining amount detecting means, the drum life detecting means,
The configuration is such that no means for detecting the full amount of waste toner is provided.
As described above, in the color image forming apparatus according to the present embodiment, when the photosensitive drum 1 which is a consumable item is replaced and the toner of each color is replenished, the photosensitive drum cartridge 7 or one type of color developing device cartridge 21 (yellow) is used. , Magenta, and cyan) will be exchanged as needed (two types of cartridges need to be exchanged).

Therefore, in addition to the cartridge containing at least the photosensitive drum 1, black, yellow, magenta,
Compared to an image forming apparatus in which each of four cyan color developing devices is used as a cartridge, it is possible to more easily replace the cartridge, which tends to be complicated. In addition, since it is not necessary to attach and detach the rotary and the color developing device cartridge that occur when the color developing device cartridge is replaced, erroneous insertion of each color developing device is eliminated, and the user can easily replace the developing means. Is now possible.

Further, in the color image forming apparatus according to this embodiment, since the black developing device 2B is not mounted on the rotary 4, the amount of black toner filled in the black developing device 3B is increased so that the black developing device 3B is Even if the size is increased, the outer diameter of the rotary 4 can be suppressed to be small, and the image forming apparatus can be downsized. Further, since the life of the black developing device 3B can be easily extended, the number of times of exchanging the black developing device 3B, which is frequently used, can be reduced, and the labor of the user for the replacement work can be reduced. .

Further, since the remaining toner amount detecting means, the drum life detecting means, and the waste toner full amount detecting means are not provided and the various detecting means are not provided, it is not necessary to provide the display means and the like, and the cost increase is suppressed. It became possible to do. In addition, the toner of the developing means contained in the photosensitive drum cartridge 7 prevents the image defect due to color mixture in other color cartridges and the dropping of the fluff, and a color image forming apparatus excellent in environmental stability and durability stability is provided. I was able to provide it.

[0073]

As described above, according to the present invention, at least one developing means among the plurality of developing means is fixedly arranged, and the developing means fixedly arranged, the image carrier, the charging means, and the The cleaning means is a process cartridge that can be attached to and detached from the color image forming apparatus, and the other developing means is mounted on a rotatable developing means holder, so that the developing cartridge can be separated from the cartridge including at least the photosensitive drum 1. As compared with an image forming apparatus in which four color, black, yellow, magenta, and cyan developing units are used as cartridges, it becomes possible to more easily replace the cartridge, which tends to be complicated.

Further, the rotatable developing means holder and the developing means mounted on the developing means holder are process cartridges that can be attached to and detached from the color image forming apparatus. Even if the amount of the developer charged in the developing means is increased and the developing means fixedly arranged is upsized, the outer diameter of the developing means rotation holder can be kept small, and the image forming apparatus can be downsized. Further, since the life of the fixedly arranged developing means can be easily extended, the number of times of exchanging the fixedly arranged developing means, which is particularly frequently used, is reduced, and the labor of the user for the exchange work is reduced. It becomes possible.

[Brief description of drawings]

FIG. 1 is a diagram illustrating a first embodiment.

FIG. 2 is a diagram illustrating a second embodiment.

FIG. 3 is a diagram illustrating a third embodiment.

FIG. 4 is a diagram illustrating a conventional color image forming apparatus.

[Explanation of symbols]

1 ... Photosensitive drum 2 ... Charging roller 5B, 30 ... Black developing device 4, 21 ... Rotary 3, 20 ... Color developer cartridge 6 ... Cleaning device 7 ... Photosensitive drum cartridge

Continued front page    (72) Inventor Jun Suzuki             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation (72) Inventor Katsuhiro Sakazawa             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation F term (reference) 2H077 AD06 AD13 BA09 BA10 EA13                       EA15 EA16 GA04 GA13                 2H134 GA01 GB02 HD01 JB01 KF05                       KJ02                 2H171 FA02 FA03 FA09 FA10 FA11                       FA13 FA14 FA17 GA12 GA14                       JA06 JA23 JA27 JA29 JA31                       KA05 QA02 QA08 QA18 QA24                       QA27 QA28 QB34 QB35 QB41                       QB42 QB47 QB49 QB50 QB52                       QB60 QC12 QC22 QC26 TB02                       TB03 UA03 UA12 VA06 WA07                       WA10                 2H200 FA12 GA23 GA47 GB12 HA02                       HA28 HB12 HB22 HB45 HB48                       JA02 JC03 JC09 LA01 LA38                       MA03 NA06                 2H300 EA01 EA05 EA06 EA13 EA14                       EA17 EB02 EB08 EB12 EB24                       EC02 EC05 EF03 EF08 EG02                       EH16 EJ09 EJ12 EJ15 EJ20                       EJ27 EJ31 EJ33 EJ35 EJ44                       EJ45 EJ47 EJ55 EJ56 EJ60                       EK03 EL04 EL07 GG33 GG34                       GG35 HH16 KK02 KK03 NN03                       NN04 PP02 PP06 RR21 RR22                       RR24

Claims (7)

[Claims] 1. A rotatable image carrier, charging means for charging the image carrier, latent image forming means for forming an electrostatic latent image on the image carrier after charging, and a static image on the image carrier. A plurality of developing means for making the latent image visible, a transferring means for transferring the visualized developer image to a transfer material, and a cleaning means for removing the developer remaining after the transfer on the image carrier. In the color image forming apparatus, at least one developing means of the plurality of developing means is fixedly arranged, and the fixedly arranged developing means, the image carrier, the charging means, and the cleaning means are provided in the color image forming apparatus. A color image forming apparatus comprising a detachable process cartridge and other developing means mounted on a rotatable developing means holder. 2. The process cartridge detachably mountable to the color image forming apparatus, wherein the rotatable developing means holder and the developing means mounted on the developing means holder are integrated. 1. The color image forming apparatus described in 1. 3. The color image forming apparatus according to claim 1, wherein at least the developer carrier of the fixedly arranged developing means is not in contact with the image carrier. 4. The color image forming apparatus according to claim 1, wherein the fixed developing unit is a developing unit containing a black developer. 5. The color image forming apparatus according to claim 1, wherein the developer contained in the fixedly arranged developing means is a magnetic one-component developer. 6. The cleaning unit according to claim 1, further comprising a cleaning member for removing the developer remaining on the image carrier and a storage member for storing the removed developer. The color image forming apparatus according to any one of items. 7. The transfer material is an intermediate transfer member that sequentially transfers multiple color developer images to a transfer material after multiple transfer, and the transfer material is an intermediate transfer member. Color image forming apparatus.